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guestfs(3) [debian man page]

guestfs(3)						      Virtualization Support							guestfs(3)

NAME
guestfs - Library for accessing and modifying virtual machine images SYNOPSIS
#include <guestfs.h> guestfs_h *g = guestfs_create (); guestfs_add_drive (g, "guest.img"); guestfs_launch (g); guestfs_mount (g, "/dev/sda1", "/"); guestfs_touch (g, "/hello"); guestfs_umount (g, "/"); guestfs_close (g); cc prog.c -o prog -lguestfs or: cc prog.c -o prog `pkg-config libguestfs --cflags --libs` DESCRIPTION
Libguestfs is a library for accessing and modifying disk images and virtual machines. This manual page documents the C API. If you are looking for an introduction to libguestfs, see the web site: <http://libguestfs.org/> Each virt tool has its own man page (for a full list, go to "SEE ALSO" at the end of this file). The libguestfs FAQ contains many useful answers: guestfs-faq(1). For examples of using the API from C, see guestfs-examples(3). For examples in other languages, see "USING LIBGUESTFS WITH OTHER PROGRAMMING LANGUAGES" below. API OVERVIEW
This section provides a gentler overview of the libguestfs API. We also try to group API calls together, where that may not be obvious from reading about the individual calls in the main section of this manual. HANDLES Before you can use libguestfs calls, you have to create a handle. Then you must add at least one disk image to the handle, followed by launching the handle, then performing whatever operations you want, and finally closing the handle. By convention we use the single letter "g" for the name of the handle variable, although of course you can use any name you want. The general structure of all libguestfs-using programs looks like this: guestfs_h *g = guestfs_create (); /* Call guestfs_add_drive additional times if there are * multiple disk images. */ guestfs_add_drive (g, "guest.img"); /* Most manipulation calls won't work until you've launched * the handle 'g'. You have to do this _after_ adding drives * and _before_ other commands. */ guestfs_launch (g); /* Now you can examine what partitions, LVs etc are available. */ char **partitions = guestfs_list_partitions (g); char **logvols = guestfs_lvs (g); /* To access a filesystem in the image, you must mount it. */ guestfs_mount (g, "/dev/sda1", "/"); /* Now you can perform filesystem actions on the guest * disk image. */ guestfs_touch (g, "/hello"); /* This is only needed for libguestfs < 1.5.24. Since then * it is done automatically when you close the handle. See * discussion of autosync in this page. */ guestfs_sync (g); /* Close the handle 'g'. */ guestfs_close (g); The code above doesn't include any error checking. In real code you should check return values carefully for errors. In general all functions that return integers return "-1" on error, and all functions that return pointers return "NULL" on error. See section "ERROR HANDLING" below for how to handle errors, and consult the documentation for each function call below to see precisely how they return error indications. See guestfs-examples(3) for fully worked examples. DISK IMAGES The image filename ("guest.img" in the example above) could be a disk image from a virtual machine, a dd(1) copy of a physical hard disk, an actual block device, or simply an empty file of zeroes that you have created through posix_fallocate(3). Libguestfs lets you do useful things to all of these. The call you should use in modern code for adding drives is "guestfs_add_drive_opts". To add a disk image, allowing writes, and specifying that the format is raw, do: guestfs_add_drive_opts (g, filename, GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw", -1); You can add a disk read-only using: guestfs_add_drive_opts (g, filename, GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw", GUESTFS_ADD_DRIVE_OPTS_READONLY, 1, -1); or by calling the older function "guestfs_add_drive_ro". In either case libguestfs won't modify the file. Be extremely cautious if the disk image is in use, eg. if it is being used by a virtual machine. Adding it read-write will almost certainly cause disk corruption, but adding it read-only is safe. You must add at least one disk image, and you may add multiple disk images. In the API, the disk images are usually referred to as "/dev/sda" (for the first one you added), "/dev/sdb" (for the second one you added), etc. Once "guestfs_launch" has been called you cannot add any more images. You can call "guestfs_list_devices" to get a list of the device names, in the order that you added them. See also "BLOCK DEVICE NAMING" below. MOUNTING Before you can read or write files, create directories and so on in a disk image that contains filesystems, you have to mount those filesystems using "guestfs_mount_options" or "guestfs_mount_ro". If you already know that a disk image contains (for example) one partition with a filesystem on that partition, then you can mount it directly: guestfs_mount_options (g, "", "/dev/sda1", "/"); where "/dev/sda1" means literally the first partition (1) of the first disk image that we added ("/dev/sda"). If the disk contains Linux LVM2 logical volumes you could refer to those instead (eg. "/dev/VG/LV"). Note that these are libguestfs virtual devices, and are nothing to do with host devices. If you are given a disk image and you don't know what it contains then you have to find out. Libguestfs can do that too: use "guestfs_list_partitions" and "guestfs_lvs" to list possible partitions and LVs, and either try mounting each to see what is mountable, or else examine them with "guestfs_vfs_type" or "guestfs_file". To list just filesystems, use "guestfs_list_filesystems". Libguestfs also has a set of APIs for inspection of unknown disk images (see "INSPECTION" below). But you might find it easier to look at higher level programs built on top of libguestfs, in particular virt-inspector(1). To mount a filesystem read-only, use "guestfs_mount_ro". There are several other variations of the "guestfs_mount_*" call. FILESYSTEM ACCESS AND MODIFICATION The majority of the libguestfs API consists of fairly low-level calls for accessing and modifying the files, directories, symlinks etc on mounted filesystems. There are over a hundred such calls which you can find listed in detail below in this man page, and we don't even pretend to cover them all in this overview. Specify filenames as full paths, starting with "/" and including the mount point. For example, if you mounted a filesystem at "/" and you want to read the file called "etc/passwd" then you could do: char *data = guestfs_cat (g, "/etc/passwd"); This would return "data" as a newly allocated buffer containing the full content of that file (with some conditions: see also "DOWNLOADING" below), or "NULL" if there was an error. As another example, to create a top-level directory on that filesystem called "var" you would do: guestfs_mkdir (g, "/var"); To create a symlink you could do: guestfs_ln_s (g, "/etc/init.d/portmap", "/etc/rc3.d/S30portmap"); Libguestfs will reject attempts to use relative paths and there is no concept of a current working directory. Libguestfs can return errors in many situations: for example if the filesystem isn't writable, or if a file or directory that you requested doesn't exist. If you are using the C API (documented here) you have to check for those error conditions after each call. (Other language bindings turn these errors into exceptions). File writes are affected by the per-handle umask, set by calling "guestfs_umask" and defaulting to 022. See "UMASK". Since libguestfs 1.18, it is possible to mount the libguestfs filesystem on a local directory, subject to some restrictions. See "MOUNT LOCAL" below. PARTITIONING Libguestfs contains API calls to read, create and modify partition tables on disk images. In the common case where you want to create a single partition covering the whole disk, you should use the "guestfs_part_disk" call: const char *parttype = "mbr"; if (disk_is_larger_than_2TB) parttype = "gpt"; guestfs_part_disk (g, "/dev/sda", parttype); Obviously this effectively wipes anything that was on that disk image before. LVM2 Libguestfs provides access to a large part of the LVM2 API, such as "guestfs_lvcreate" and "guestfs_vgremove". It won't make much sense unless you familiarize yourself with the concepts of physical volumes, volume groups and logical volumes. This author strongly recommends reading the LVM HOWTO, online at http://tldp.org/HOWTO/LVM-HOWTO/ <http://tldp.org/HOWTO/LVM-HOWTO/>. DOWNLOADING Use "guestfs_cat" to download small, text only files. This call is limited to files which are less than 2 MB and which cannot contain any ASCII NUL ("") characters. However the API is very simple to use. "guestfs_read_file" can be used to read files which contain arbitrary 8 bit data, since it returns a (pointer, size) pair. However it is still limited to "small" files, less than 2 MB. "guestfs_download" can be used to download any file, with no limits on content or size (even files larger than 4 GB). To download multiple files, see "guestfs_tar_out" and "guestfs_tgz_out". UPLOADING It's often the case that you want to write a file or files to the disk image. To write a small file with fixed content, use "guestfs_write". To create a file of all zeroes, use "guestfs_truncate_size" (sparse) or "guestfs_fallocate64" (with all disk blocks allocated). There are a variety of other functions for creating test files, for example "guestfs_fill" and "guestfs_fill_pattern". To upload a single file, use "guestfs_upload". This call has no limits on file content or size (even files larger than 4 GB). To upload multiple files, see "guestfs_tar_in" and "guestfs_tgz_in". However the fastest way to upload large numbers of arbitrary files is to turn them into a squashfs or CD ISO (see mksquashfs(8) and mkisofs(8)), then attach this using "guestfs_add_drive_ro". If you add the drive in a predictable way (eg. adding it last after all other drives) then you can get the device name from "guestfs_list_devices" and mount it directly using "guestfs_mount_ro". Note that squashfs images are sometimes non-portable between kernel versions, and they don't support labels or UUIDs. If you want to pre-build an image or you need to mount it using a label or UUID, use an ISO image instead. COPYING There are various different commands for copying between files and devices and in and out of the guest filesystem. These are summarised in the table below. file to file Use "guestfs_cp" to copy a single file, or "guestfs_cp_a" to copy directories recursively. To copy part of a file (offset and size) use "guestfs_copy_file_to_file". file to device device to file device to device Use "guestfs_copy_file_to_device", "guestfs_copy_device_to_file", or "guestfs_copy_device_to_device". Example: duplicate the contents of an LV: guestfs_copy_device_to_device (g, "/dev/VG/Original", "/dev/VG/Copy", /* -1 marks the end of the list of optional parameters */ -1); The destination ("/dev/VG/Copy") must be at least as large as the source ("/dev/VG/Original"). To copy less than the whole source device, use the optional "size" parameter: guestfs_copy_device_to_device (g, "/dev/VG/Original", "/dev/VG/Copy", GUESTFS_COPY_DEVICE_TO_DEVICE_SIZE, 10000, -1); file on the host to file or device Use "guestfs_upload". See "UPLOADING" above. file or device to file on the host Use "guestfs_download". See "DOWNLOADING" above. UPLOADING AND DOWNLOADING TO PIPES AND FILE DESCRIPTORS Calls like "guestfs_upload", "guestfs_download", "guestfs_tar_in", "guestfs_tar_out" etc appear to only take filenames as arguments, so it appears you can only upload and download to files. However many Un*x-like hosts let you use the special device files "/dev/stdin", "/dev/stdout", "/dev/stderr" and "/dev/fd/N" to read and write from stdin, stdout, stderr, and arbitrary file descriptor N. For example, virt-cat(1) writes its output to stdout by doing: guestfs_download (g, filename, "/dev/stdout"); and you can write tar output to a file descriptor "fd" by doing: char devfd[64]; snprintf (devfd, sizeof devfd, "/dev/fd/%d", fd); guestfs_tar_out (g, "/", devfd); LISTING FILES "guestfs_ll" is just designed for humans to read (mainly when using the guestfish(1)-equivalent command "ll"). "guestfs_ls" is a quick way to get a list of files in a directory from programs, as a flat list of strings. "guestfs_readdir" is a programmatic way to get a list of files in a directory, plus additional information about each one. It is more equivalent to using the readdir(3) call on a local filesystem. "guestfs_find" and "guestfs_find0" can be used to recursively list files. RUNNING COMMANDS Although libguestfs is primarily an API for manipulating files inside guest images, we also provide some limited facilities for running commands inside guests. There are many limitations to this: o The kernel version that the command runs under will be different from what it expects. o If the command needs to communicate with daemons, then most likely they won't be running. o The command will be running in limited memory. o The network may not be available unless you enable it (see "guestfs_set_network"). o Only supports Linux guests (not Windows, BSD, etc). o Architecture limitations (eg. won't work for a PPC guest on an X86 host). o For SELinux guests, you may need to enable SELinux and load policy first. See "SELINUX" in this manpage. o Security: It is not safe to run commands from untrusted, possibly malicious guests. These commands may attempt to exploit your program by sending unexpected output. They could also try to exploit the Linux kernel or qemu provided by the libguestfs appliance. They could use the network provided by the libguestfs appliance to bypass ordinary network partitions and firewalls. They could use the elevated privileges or different SELinux context of your program to their advantage. A secure alternative is to use libguestfs to install a "firstboot" script (a script which runs when the guest next boots normally), and to have this script run the commands you want in the normal context of the running guest, network security and so on. For information about other security issues, see "SECURITY". The two main API calls to run commands are "guestfs_command" and "guestfs_sh" (there are also variations). The difference is that "guestfs_sh" runs commands using the shell, so any shell globs, redirections, etc will work. CONFIGURATION FILES To read and write configuration files in Linux guest filesystems, we strongly recommend using Augeas. For example, Augeas understands how to read and write, say, a Linux shadow password file or X.org configuration file, and so avoids you having to write that code. The main Augeas calls are bound through the "guestfs_aug_*" APIs. We don't document Augeas itself here because there is excellent documentation on the <http://augeas.net/> website. If you don't want to use Augeas (you fool!) then try calling "guestfs_read_lines" to get the file as a list of lines which you can iterate over. SELINUX We support SELinux guests. To ensure that labeling happens correctly in SELinux guests, you need to enable SELinux and load the guest's policy: 1. Before launching, do: guestfs_set_selinux (g, 1); 2. After mounting the guest's filesystem(s), load the policy. This is best done by running the load_policy(8) command in the guest itself: guestfs_sh (g, "/usr/sbin/load_policy"); (Older versions of "load_policy" require you to specify the name of the policy file). 3. Optionally, set the security context for the API. The correct security context to use can only be known by inspecting the guest. As an example: guestfs_setcon (g, "unconfined_u:unconfined_r:unconfined_t:s0"); This will work for running commands and editing existing files. When new files are created, you may need to label them explicitly, for example by running the external command "restorecon pathname". UMASK Certain calls are affected by the current file mode creation mask (the "umask"). In particular ones which create files or directories, such as "guestfs_touch", "guestfs_mknod" or "guestfs_mkdir". This affects either the default mode that the file is created with or modifies the mode that you supply. The default umask is 022, so files are created with modes such as 0644 and directories with 0755. There are two ways to avoid being affected by umask. Either set umask to 0 (call "guestfs_umask (g, 0)" early after launching). Or call "guestfs_chmod" after creating each file or directory. For more information about umask, see umask(2). ENCRYPTED DISKS Libguestfs allows you to access Linux guests which have been encrypted using whole disk encryption that conforms to the Linux Unified Key Setup (LUKS) standard. This includes nearly all whole disk encryption systems used by modern Linux guests. Use "guestfs_vfs_type" to identify LUKS-encrypted block devices (it returns the string "crypto_LUKS"). Then open these devices by calling "guestfs_luks_open". Obviously you will require the passphrase! Opening a LUKS device creates a new device mapper device called "/dev/mapper/mapname" (where "mapname" is the string you supply to "guestfs_luks_open"). Reads and writes to this mapper device are decrypted from and encrypted to the underlying block device respectively. LVM volume groups on the device can be made visible by calling "guestfs_vgscan" followed by "guestfs_vg_activate_all". The logical volume(s) can now be mounted in the usual way. Use the reverse process to close a LUKS device. Unmount any logical volumes on it, deactivate the volume groups by caling "guestfs_vg_activate (g, 0, ["/dev/VG"])". Then close the mapper device by calling "guestfs_luks_close" on the "/dev/mapper/mapname" device (not the underlying encrypted block device). MOUNT LOCAL In libguestfs >= 1.18, it is possible to mount the libguestfs filesystem on a local directory and access it using ordinary POSIX calls and programs. Availability of this is subject to a number of restrictions: it requires FUSE (the Filesystem in USErspace), and libfuse must also have been available when libguestfs was compiled. FUSE may require that a kernel module is loaded, and it may be necessary to add the current user to a special "fuse" group. See the documentation for your distribution and <http://fuse.sf.net> for further information. The call to mount the libguestfs filesystem on a local directory is "guestfs_mount_local" (q.v.) followed by "guestfs_mount_local_run". The latter does not return until you unmount the filesystem. The reason is that the call enters the FUSE main loop and processes kernel requests, turning them into libguestfs calls. An alternative design would have been to create a background thread to do this, but libguestfs doesn't require pthreads. This way is also more flexible: for example the user can create another thread for "guestfs_mount_local_run". "guestfs_mount_local" needs a certain amount of time to set up the mountpoint. The mountpoint is not ready to use until the call returns. At this point, accesses to the filesystem will block until the main loop is entered (ie. "guestfs_mount_local_run"). So if you need to start another process to access the filesystem, put the fork between "guestfs_mount_local" and "guestfs_mount_local_run". MOUNT LOCAL COMPATIBILITY Since local mounting was only added in libguestfs 1.18, and may not be available even in these builds, you should consider writing code so that it doesn't depend on this feature, and can fall back to using libguestfs file system calls. If libguestfs was compiled without support for "guestfs_mount_local" then calling it will return an error with errno set to "ENOTSUP" (see "guestfs_last_errno"). MOUNT LOCAL PERFORMANCE Libguestfs on top of FUSE performs quite poorly. For best performance do not use it. Use ordinary libguestfs filesystem calls, upload, download etc. instead. INSPECTION Libguestfs has APIs for inspecting an unknown disk image to find out if it contains operating systems, an install CD or a live CD. (These APIs used to be in a separate Perl-only library called Sys::Guestfs::Lib(3) but since version 1.5.3 the most frequently used part of this library has been rewritten in C and moved into the core code). Add all disks belonging to the unknown virtual machine and call "guestfs_launch" in the usual way. Then call "guestfs_inspect_os". This function uses other libguestfs calls and certain heuristics, and returns a list of operating systems that were found. An empty list means none were found. A single element is the root filesystem of the operating system. For dual- or multi-boot guests, multiple roots can be returned, each one corresponding to a separate operating system. (Multi-boot virtual machines are extremely rare in the world of virtualization, but since this scenario can happen, we have built libguestfs to deal with it.) For each root, you can then call various "guestfs_inspect_get_*" functions to get additional details about that operating system. For example, call "guestfs_inspect_get_type" to return the string "windows" or "linux" for Windows and Linux-based operating systems respectively. Un*x-like and Linux-based operating systems usually consist of several filesystems which are mounted at boot time (for example, a separate boot partition mounted on "/boot"). The inspection rules are able to detect how filesystems correspond to mount points. Call "guestfs_inspect_get_mountpoints" to get this mapping. It might return a hash table like this example: /boot => /dev/sda1 / => /dev/vg_guest/lv_root /usr => /dev/vg_guest/lv_usr The caller can then make calls to "guestfs_mount_options" to mount the filesystems as suggested. Be careful to mount filesystems in the right order (eg. "/" before "/usr"). Sorting the keys of the hash by length, shortest first, should work. Inspection currently only works for some common operating systems. Contributors are welcome to send patches for other operating systems that we currently cannot detect. Encrypted disks must be opened before inspection. See "ENCRYPTED DISKS" for more details. The "guestfs_inspect_os" function just ignores any encrypted devices. A note on the implementation: The call "guestfs_inspect_os" performs inspection and caches the results in the guest handle. Subsequent calls to "guestfs_inspect_get_*" return this cached information, but do not re-read the disks. If you change the content of the guest disks, you can redo inspection by calling "guestfs_inspect_os" again. ("guestfs_inspect_list_applications" works a little differently from the other calls and does read the disks. See documentation for that function for details). INSPECTING INSTALL DISKS Libguestfs (since 1.9.4) can detect some install disks, install CDs, live CDs and more. Call "guestfs_inspect_get_format" to return the format of the operating system, which currently can be "installed" (a regular operating system) or "installer" (some sort of install disk). Further information is available about the operating system that can be installed using the regular inspection APIs like "guestfs_inspect_get_product_name", "guestfs_inspect_get_major_version" etc. Some additional information specific to installer disks is also available from the "guestfs_inspect_is_live", "guestfs_inspect_is_netinst" and "guestfs_inspect_is_multipart" calls. SPECIAL CONSIDERATIONS FOR WINDOWS GUESTS Libguestfs can mount NTFS partitions. It does this using the http://www.ntfs-3g.org/ <http://www.ntfs-3g.org/> driver. DRIVE LETTERS AND PATHS DOS and Windows still use drive letters, and the filesystems are always treated as case insensitive by Windows itself, and therefore you might find a Windows configuration file referring to a path like "c:windowssystem32". When the filesystem is mounted in libguestfs, that directory might be referred to as "/WINDOWS/System32". Drive letter mappings can be found using inspection (see "INSPECTION" and "guestfs_inspect_get_drive_mappings") Dealing with separator characters (backslash vs forward slash) is outside the scope of libguestfs, but usually a simple character replacement will work. To resolve the case insensitivity of paths, call "guestfs_case_sensitive_path". ACCESSING THE WINDOWS REGISTRY Libguestfs also provides some help for decoding Windows Registry "hive" files, through the library "hivex" which is part of the libguestfs project although ships as a separate tarball. You have to locate and download the hive file(s) yourself, and then pass them to "hivex" functions. See also the programs hivexml(1), hivexsh(1), hivexregedit(1) and virt-win-reg(1) for more help on this issue. SYMLINKS ON NTFS-3G FILESYSTEMS Ntfs-3g tries to rewrite "Junction Points" and NTFS "symbolic links" to provide something which looks like a Linux symlink. The way it tries to do the rewriting is described here: http://www.tuxera.com/community/ntfs-3g-advanced/junction-points-and-symbolic-links/ <http://www.tuxera.com/community/ntfs-3g- advanced/junction-points-and-symbolic-links/> The essential problem is that ntfs-3g simply does not have enough information to do a correct job. NTFS links can contain drive letters and references to external device GUIDs that ntfs-3g has no way of resolving. It is almost certainly the case that libguestfs callers should ignore what ntfs-3g does (ie. don't use "guestfs_readlink" on NTFS volumes). Instead if you encounter a symbolic link on an ntfs-3g filesystem, use "guestfs_lgetxattr" to read the "system.ntfs_reparse_data" extended attribute, and read the raw reparse data from that (you can find the format documented in various places around the web). EXTENDED ATTRIBUTES ON NTFS-3G FILESYSTEMS There are other useful extended attributes that can be read from ntfs-3g filesystems (using "guestfs_getxattr"). See: http://www.tuxera.com/community/ntfs-3g-advanced/extended-attributes/ <http://www.tuxera.com/community/ntfs-3g-advanced/extended- attributes/> RESIZE2FS ERRORS The "guestfs_resize2fs", "guestfs_resize2fs_size" and "guestfs_resize2fs_M" calls are used to resize ext2/3/4 filesystems. The underlying program (resize2fs(8)) requires that the filesystem is clean and recently fsck'd before you can resize it. Also, if the resize operation fails for some reason, then you had to call fsck the filesystem again to fix it. In libguestfs "lt" 1.17.14, you usually had to call "guestfs_e2fsck_f" before the resize. However, in "ge" 1.17.14, e2fsck(8) is called automatically before the resize, so you no longer need to do this. The resize2fs(8) program can still fail, in which case it prints an error message similar to: Please run 'e2fsck -fy <device>' to fix the filesystem after the aborted resize operation. You can do this by calling "guestfs_e2fsck" with the "forceall" option. However in the context of disk images, it is usually better to avoid this situation, eg. by rolling back to an earlier snapshot, or by copying and resizing and on failure going back to the original. USING LIBGUESTFS WITH OTHER PROGRAMMING LANGUAGES Although we don't want to discourage you from using the C API, we will mention here that the same API is also available in other languages. The API is broadly identical in all supported languages. This means that the C call "guestfs_add_drive_ro(g,file)" is "$g->add_drive_ro($file)" in Perl, "g.add_drive_ro(file)" in Python, and "g#add_drive_ro file" in OCaml. In other words, a straightforward, predictable isomorphism between each language. Error messages are automatically transformed into exceptions if the language supports it. We don't try to "object orientify" parts of the API in OO languages, although contributors are welcome to write higher level APIs above what we provide in their favourite languages if they wish. C++ You can use the guestfs.h header file from C++ programs. The C++ API is identical to the C API. C++ classes and exceptions are not used. C# The C# bindings are highly experimental. Please read the warnings at the top of "csharp/Libguestfs.cs". Erlang See guestfs-erlang(3). GObject Experimental GObject bindings (with GObject Introspection support) are available. See the "gobject" directory in the source. Haskell This is the only language binding that is working but incomplete. Only calls which return simple integers have been bound in Haskell, and we are looking for help to complete this binding. Java Full documentation is contained in the Javadoc which is distributed with libguestfs. For examples, see guestfs-java(3). OCaml See guestfs-ocaml(3). Perl See guestfs-perl(3) and Sys::Guestfs(3). PHP For documentation see "README-PHP" supplied with libguestfs sources or in the php-libguestfs package for your distribution. The PHP binding only works correctly on 64 bit machines. Python See guestfs-python(3). Ruby See guestfs-ruby(3). For JRuby, use the Java bindings. shell scripts See guestfish(1). LIBGUESTFS GOTCHAS <http://en.wikipedia.org/wiki/Gotcha_(programming)>: "A feature of a system [...] that works in the way it is documented but is counterintuitive and almost invites mistakes." Since we developed libguestfs and the associated tools, there are several things we would have designed differently, but are now stuck with for backwards compatibility or other reasons. If there is ever a libguestfs 2.0 release, you can expect these to change. Beware of them. Autosync / forgetting to sync. Update: Autosync is enabled by default for all API users starting from libguestfs 1.5.24. This section only applies to older versions. When modifying a filesystem from C or another language, you must unmount all filesystems and call "guestfs_sync" explicitly before you close the libguestfs handle. You can also call: guestfs_set_autosync (g, 1); to have the unmount/sync done automatically for you when the handle 'g' is closed. (This feature is called "autosync", "guestfs_set_autosync" q.v.) If you forget to do this, then it is entirely possible that your changes won't be written out, or will be partially written, or (very rarely) that you'll get disk corruption. Note that in guestfish(3) autosync is the default. So quick and dirty guestfish scripts that forget to sync will work just fine, which can make this very puzzling if you are trying to debug a problem. Mount option "-o sync" should not be the default. Update: "guestfs_mount" no longer adds any options starting from libguestfs 1.13.16. This section only applies to older versions. If you use "guestfs_mount", then "-o sync,noatime" are added implicitly. However "-o sync" does not add any reliability benefit, but does have a very large performance impact. The work around is to use "guestfs_mount_options" and set the mount options that you actually want to use. Read-only should be the default. In guestfish(3), --ro should be the default, and you should have to specify --rw if you want to make changes to the image. This would reduce the potential to corrupt live VM images. Note that many filesystems change the disk when you just mount and unmount, even if you didn't perform any writes. You need to use "guestfs_add_drive_ro" to guarantee that the disk is not changed. guestfish command line is hard to use. "guestfish disk.img" doesn't do what people expect (open "disk.img" for examination). It tries to run a guestfish command "disk.img" which doesn't exist, so it fails. In earlier versions of guestfish the error message was also unintuitive, but we have corrected this since. Like the Bourne shell, we should have used "guestfish -c command" to run commands. guestfish megabyte modifiers don't work right on all commands In recent guestfish you can use "1M" to mean 1 megabyte (and similarly for other modifiers). What guestfish actually does is to multiply the number part by the modifier part and pass the result to the C API. However this doesn't work for a few APIs which aren't expecting bytes, but are already expecting some other unit (eg. megabytes). The most common is "guestfs_lvcreate". The guestfish command: lvcreate LV VG 100M does not do what you might expect. Instead because "guestfs_lvcreate" is already expecting megabytes, this tries to create a 100 terabyte (100 megabytes * megabytes) logical volume. The error message you get from this is also a little obscure. This could be fixed in the generator by specially marking parameters and return values which take bytes or other units. Ambiguity between devices and paths There is a subtle ambiguity in the API between a device name (eg. "/dev/sdb2") and a similar pathname. A file might just happen to be called "sdb2" in the directory "/dev" (consider some non-Unix VM image). In the current API we usually resolve this ambiguity by having two separate calls, for example "guestfs_checksum" and "guestfs_checksum_device". Some API calls are ambiguous and (incorrectly) resolve the problem by detecting if the path supplied begins with "/dev/". To avoid both the ambiguity and the need to duplicate some calls, we could make paths/devices into structured names. One way to do this would be to use a notation like grub ("hd(0,0)"), although nobody really likes this aspect of grub. Another way would be to use a structured type, equivalent to this OCaml type: type path = Path of string | Device of int | Partition of int * int which would allow you to pass arguments like: Path "/foo/bar" Device 1 (* /dev/sdb, or perhaps /dev/sda *) Partition (1, 2) (* /dev/sdb2 (or is it /dev/sda2 or /dev/sdb3?) *) Path "/dev/sdb2" (* not a device *) As you can see there are still problems to resolve even with this representation. Also consider how it might work in guestfish. KEYS AND PASSPHRASES Certain libguestfs calls take a parameter that contains sensitive key material, passed in as a C string. In the future we would hope to change the libguestfs implementation so that keys are mlock(2)-ed into physical RAM, and thus can never end up in swap. However this is not done at the moment, because of the complexity of such an implementation. Therefore you should be aware that any key parameter you pass to libguestfs might end up being written out to the swap partition. If this is a concern, scrub the swap partition or don't use libguestfs on encrypted devices. MULTIPLE HANDLES AND MULTIPLE THREADS All high-level libguestfs actions are synchronous. If you want to use libguestfs asynchronously then you must create a thread. Only use the handle from a single thread. Either use the handle exclusively from one thread, or provide your own mutex so that two threads cannot issue calls on the same handle at the same time. See the graphical program guestfs-browser for one possible architecture for multithreaded programs using libvirt and libguestfs. PATH Libguestfs needs a supermin appliance, which it finds by looking along an internal path. By default it looks for these in the directory "$libdir/guestfs" (eg. "/usr/local/lib/guestfs" or "/usr/lib64/guestfs"). Use "guestfs_set_path" or set the environment variable "LIBGUESTFS_PATH" to change the directories that libguestfs will search in. The value is a colon-separated list of paths. The current directory is not searched unless the path contains an empty element or ".". For example "LIBGUESTFS_PATH=:/usr/lib/guestfs" would search the current directory and then "/usr/lib/guestfs". QEMU WRAPPERS If you want to compile your own qemu, run qemu from a non-standard location, or pass extra arguments to qemu, then you can write a shell- script wrapper around qemu. There is one important rule to remember: you must "exec qemu" as the last command in the shell script (so that qemu replaces the shell and becomes the direct child of the libguestfs-using program). If you don't do this, then the qemu process won't be cleaned up correctly. Here is an example of a wrapper, where I have built my own copy of qemu from source: #!/bin/sh - qemudir=/home/rjones/d/qemu exec $qemudir/x86_64-softmmu/qemu-system-x86_64 -L $qemudir/pc-bios "$@" Save this script as "/tmp/qemu.wrapper" (or wherever), "chmod +x", and then use it by setting the LIBGUESTFS_QEMU environment variable. For example: LIBGUESTFS_QEMU=/tmp/qemu.wrapper guestfish Note that libguestfs also calls qemu with the -help and -version options in order to determine features. Wrappers can also be used to edit the options passed to qemu. In the following example, the "-machine ..." option ("-machine" and the following argument) are removed from the command line and replaced with "-machine pc,accel=tcg". The while loop iterates over the options until it finds the right one to remove, putting the remaining options into the "args" array. #!/bin/bash - i=0 while [ $# -gt 0 ]; do case "$1" in -machine) shift 2;; *) args[i]="$1" (( i++ )) shift ;; esac done exec qemu-kvm -machine pc,accel=tcg "${args[@]}" ATTACHING TO RUNNING DAEMONS Note (1): This is highly experimental and has a tendency to eat babies. Use with caution. Note (2): This section explains how to attach to a running daemon from a low level perspective. For most users, simply using virt tools such as guestfish(1) with the --live option will "just work". Using guestfs_set_attach_method By calling "guestfs_set_attach_method" you can change how the library connects to the "guestfsd" daemon in "guestfs_launch" (read "ARCHITECTURE" for some background). The normal attach method is "appliance", where a small appliance is created containing the daemon, and then the library connects to this. Setting attach method to "unix:path" (where path is the path of a Unix domain socket) causes "guestfs_launch" to connect to an existing daemon over the Unix domain socket. The normal use for this is to connect to a running virtual machine that contains a "guestfsd" daemon, and send commands so you can read and write files inside the live virtual machine. Using guestfs_add_domain with live flag "guestfs_add_domain" provides some help for getting the correct attach method. If you pass the "live" option to this function, then (if the virtual machine is running) it will examine the libvirt XML looking for a virtio-serial channel to connect to: <domain> ... <devices> ... <channel type='unix'> <source mode='bind' path='/path/to/socket'/> <target type='virtio' name='org.libguestfs.channel.0'/> </channel> ... </devices> </domain> "guestfs_add_domain" extracts "/path/to/socket" and sets the attach method to "unix:/path/to/socket". Some of the libguestfs tools (including guestfish) support a --live option which is passed through to "guestfs_add_domain" thus allowing you to attach to and modify live virtual machines. The virtual machine needs to have been set up beforehand so that it has the virtio-serial channel and so that guestfsd is running inside it. ABI GUARANTEE We guarantee the libguestfs ABI (binary interface), for public, high-level actions as outlined in this section. Although we will deprecate some actions, for example if they get replaced by newer calls, we will keep the old actions forever. This allows you the developer to program in confidence against the libguestfs API. BLOCK DEVICE NAMING In the kernel there is now quite a profusion of schemata for naming block devices (in this context, by block device I mean a physical or virtual hard drive). The original Linux IDE driver used names starting with "/dev/hd*". SCSI devices have historically used a different naming scheme, "/dev/sd*". When the Linux kernel libata driver became a popular replacement for the old IDE driver (particularly for SATA devices) those devices also used the "/dev/sd*" scheme. Additionally we now have virtual machines with paravirtualized drivers. This has created several different naming systems, such as "/dev/vd*" for virtio disks and "/dev/xvd*" for Xen PV disks. As discussed above, libguestfs uses a qemu appliance running an embedded Linux kernel to access block devices. We can run a variety of appliances based on a variety of Linux kernels. This causes a problem for libguestfs because many API calls use device or partition names. Working scripts and the recipe (example) scripts that we make available over the internet could fail if the naming scheme changes. Therefore libguestfs defines "/dev/sd*" as the standard naming scheme. Internally "/dev/sd*" names are translated, if necessary, to other names as required. For example, under RHEL 5 which uses the "/dev/hd*" scheme, any device parameter "/dev/sda2" is translated to "/dev/hda2" transparently. Note that this only applies to parameters. The "guestfs_list_devices", "guestfs_list_partitions" and similar calls return the true names of the devices and partitions as known to the appliance. ALGORITHM FOR BLOCK DEVICE NAME TRANSLATION Usually this translation is transparent. However in some (very rare) cases you may need to know the exact algorithm. Such cases include where you use "guestfs_config" to add a mixture of virtio and IDE devices to the qemu-based appliance, so have a mixture of "/dev/sd*" and "/dev/vd*" devices. The algorithm is applied only to parameters which are known to be either device or partition names. Return values from functions such as "guestfs_list_devices" are never changed. o Is the string a parameter which is a device or partition name? o Does the string begin with "/dev/sd"? o Does the named device exist? If so, we use that device. However if not then we continue with this algorithm. o Replace initial "/dev/sd" string with "/dev/hd". For example, change "/dev/sda2" to "/dev/hda2". If that named device exists, use it. If not, continue. o Replace initial "/dev/sd" string with "/dev/vd". If that named device exists, use it. If not, return an error. PORTABILITY CONCERNS WITH BLOCK DEVICE NAMING Although the standard naming scheme and automatic translation is useful for simple programs and guestfish scripts, for larger programs it is best not to rely on this mechanism. Where possible for maximum future portability programs using libguestfs should use these future-proof techniques: o Use "guestfs_list_devices" or "guestfs_list_partitions" to list actual device names, and then use those names directly. Since those device names exist by definition, they will never be translated. o Use higher level ways to identify filesystems, such as LVM names, UUIDs and filesystem labels. SECURITY
This section discusses security implications of using libguestfs, particularly with untrusted or malicious guests or disk images. GENERAL SECURITY CONSIDERATIONS Be careful with any files or data that you download from a guest (by "download" we mean not just the "guestfs_download" command but any command that reads files, filenames, directories or anything else from a disk image). An attacker could manipulate the data to fool your program into doing the wrong thing. Consider cases such as: o the data (file etc) not being present o being present but empty o being much larger than normal o containing arbitrary 8 bit data o being in an unexpected character encoding o containing homoglyphs. SECURITY OF MOUNTING FILESYSTEMS When you mount a filesystem under Linux, mistakes in the kernel filesystem (VFS) module can sometimes be escalated into exploits by deliberately creating a malicious, malformed filesystem. These exploits are very severe for two reasons. Firstly there are very many filesystem drivers in the kernel, and many of them are infrequently used and not much developer attention has been paid to the code. Linux userspace helps potential crackers by detecting the filesystem type and automatically choosing the right VFS driver, even if that filesystem type is obscure or unexpected for the administrator. Secondly, a kernel-level exploit is like a local root exploit (worse in some ways), giving immediate and total access to the system right down to the hardware level. That explains why you should never mount a filesystem from an untrusted guest on your host kernel. How about libguestfs? We run a Linux kernel inside a qemu virtual machine, usually running as a non-root user. The attacker would need to write a filesystem which first exploited the kernel, and then exploited either qemu virtualization (eg. a faulty qemu driver) or the libguestfs protocol, and finally to be as serious as the host kernel exploit it would need to escalate its privileges to root. This multi-step escalation, performed by a static piece of data, is thought to be extremely hard to do, although we never say 'never' about security issues. In any case callers can reduce the attack surface by forcing the filesystem type when mounting (use "guestfs_mount_vfs"). PROTOCOL SECURITY The protocol is designed to be secure, being based on RFC 4506 (XDR) with a defined upper message size. However a program that uses libguestfs must also take care - for example you can write a program that downloads a binary from a disk image and executes it locally, and no amount of protocol security will save you from the consequences. INSPECTION SECURITY Parts of the inspection API (see "INSPECTION") return untrusted strings directly from the guest, and these could contain any 8 bit data. Callers should be careful to escape these before printing them to a structured file (for example, use HTML escaping if creating a web page). Guest configuration may be altered in unusual ways by the administrator of the virtual machine, and may not reflect reality (particularly for untrusted or actively malicious guests). For example we parse the hostname from configuration files like "/etc/sysconfig/network" that we find in the guest, but the guest administrator can easily manipulate these files to provide the wrong hostname. The inspection API parses guest configuration using two external libraries: Augeas (Linux configuration) and hivex (Windows Registry). Both are designed to be robust in the face of malicious data, although denial of service attacks are still possible, for example with oversized configuration files. RUNNING UNTRUSTED GUEST COMMANDS Be very cautious about running commands from the guest. By running a command in the guest, you are giving CPU time to a binary that you do not control, under the same user account as the library, albeit wrapped in qemu virtualization. More information and alternatives can be found in the section "RUNNING COMMANDS". CVE-2010-3851 https://bugzilla.redhat.com/642934 This security bug concerns the automatic disk format detection that qemu does on disk images. A raw disk image is just the raw bytes, there is no header. Other disk images like qcow2 contain a special header. Qemu deals with this by looking for one of the known headers, and if none is found then assuming the disk image must be raw. This allows a guest which has been given a raw disk image to write some other header. At next boot (or when the disk image is accessed by libguestfs) qemu would do autodetection and think the disk image format was, say, qcow2 based on the header written by the guest. This in itself would not be a problem, but qcow2 offers many features, one of which is to allow a disk image to refer to another image (called the "backing disk"). It does this by placing the path to the backing disk into the qcow2 header. This path is not validated and could point to any host file (eg. "/etc/passwd"). The backing disk is then exposed through "holes" in the qcow2 disk image, which of course is completely under the control of the attacker. In libguestfs this is rather hard to exploit except under two circumstances: 1. You have enabled the network or have opened the disk in write mode. 2. You are also running untrusted code from the guest (see "RUNNING COMMANDS"). The way to avoid this is to specify the expected disk format when adding disks (the optional "format" option to "guestfs_add_drive_opts"). You should always do this if the disk is raw format, and it's a good idea for other cases too. For disks added from libvirt using calls like "guestfs_add_domain", the format is fetched from libvirt and passed through. For libguestfs tools, use the --format command line parameter as appropriate. CONNECTION MANAGEMENT
guestfs_h * "guestfs_h" is the opaque type representing a connection handle. Create a handle by calling "guestfs_create". Call "guestfs_close" to free the handle and release all resources used. For information on using multiple handles and threads, see the section "MULTIPLE HANDLES AND MULTIPLE THREADS" above. guestfs_create guestfs_h *guestfs_create (void); Create a connection handle. On success this returns a non-NULL pointer to a handle. On error it returns NULL. You have to "configure" the handle after creating it. This includes calling "guestfs_add_drive_opts" (or one of the equivalent calls) on the handle at least once. After configuring the handle, you have to call "guestfs_launch". You may also want to configure error handling for the handle. See the "ERROR HANDLING" section below. guestfs_close void guestfs_close (guestfs_h *g); This closes the connection handle and frees up all resources used. If autosync was set on the handle and the handle was launched, then this implicitly calls various functions to unmount filesystems and sync the disk. See "guestfs_set_autosync" for more details. If a close callback was set on the handle, then it is called. ERROR HANDLING
API functions can return errors. For example, almost all functions that return "int" will return "-1" to indicate an error. Additional information is available for errors: an error message string and optionally an error number (errno) if the thing that failed was a system call. You can get at the additional information about the last error on the handle by calling "guestfs_last_error", "guestfs_last_errno", and/or by setting up an error handler with "guestfs_set_error_handler". When the handle is created, a default error handler is installed which prints the error message string to "stderr". For small short- running command line programs it is sufficient to do: if (guestfs_launch (g) == -1) exit (EXIT_FAILURE); since the default error handler will ensure that an error message has been printed to "stderr" before the program exits. For other programs the caller will almost certainly want to install an alternate error handler or do error handling in-line like this: /* This disables the default behaviour of printing errors on stderr. */ guestfs_set_error_handler (g, NULL, NULL); if (guestfs_launch (g) == -1) { /* Examine the error message and print it etc. */ char *msg = guestfs_last_error (g); int errnum = guestfs_last_errno (g); fprintf (stderr, "%s", msg); if (errnum != 0) fprintf (stderr, ": %s", strerror (errnum)); fprintf (stderr, " "); /* ... */ } Out of memory errors are handled differently. The default action is to call abort(3). If this is undesirable, then you can set a handler using "guestfs_set_out_of_memory_handler". "guestfs_create" returns "NULL" if the handle cannot be created, and because there is no handle if this happens there is no way to get additional error information. However "guestfs_create" is supposed to be a lightweight operation which can only fail because of insufficient memory (it returns NULL in this case). guestfs_last_error const char *guestfs_last_error (guestfs_h *g); This returns the last error message that happened on "g". If there has not been an error since the handle was created, then this returns "NULL". The lifetime of the returned string is until the next error occurs, or "guestfs_close" is called. guestfs_last_errno int guestfs_last_errno (guestfs_h *g); This returns the last error number (errno) that happened on "g". If successful, an errno integer not equal to zero is returned. If no error, this returns 0. This call can return 0 in three situations: 1. There has not been any error on the handle. 2. There has been an error but the errno was meaningless. This corresponds to the case where the error did not come from a failed system call, but for some other reason. 3. There was an error from a failed system call, but for some reason the errno was not captured and returned. This usually indicates a bug in libguestfs. Libguestfs tries to convert the errno from inside the applicance into a corresponding errno for the caller (not entirely trivial: the appliance might be running a completely different operating system from the library and error numbers are not standardized across Un*xen). If this could not be done, then the error is translated to "EINVAL". In practice this should only happen in very rare circumstances. guestfs_set_error_handler typedef void (*guestfs_error_handler_cb) (guestfs_h *g, void *opaque, const char *msg); void guestfs_set_error_handler (guestfs_h *g, guestfs_error_handler_cb cb, void *opaque); The callback "cb" will be called if there is an error. The parameters passed to the callback are an opaque data pointer and the error message string. "errno" is not passed to the callback. To get that the callback must call "guestfs_last_errno". Note that the message string "msg" is freed as soon as the callback function returns, so if you want to stash it somewhere you must make your own copy. The default handler prints messages on "stderr". If you set "cb" to "NULL" then no handler is called. guestfs_get_error_handler guestfs_error_handler_cb guestfs_get_error_handler (guestfs_h *g, void **opaque_rtn); Returns the current error handler callback. guestfs_set_out_of_memory_handler typedef void (*guestfs_abort_cb) (void); void guestfs_set_out_of_memory_handler (guestfs_h *g, guestfs_abort_cb); The callback "cb" will be called if there is an out of memory situation. Note this callback must not return. The default is to call abort(3). You cannot set "cb" to "NULL". You can't ignore out of memory situations. guestfs_get_out_of_memory_handler guestfs_abort_fn guestfs_get_out_of_memory_handler (guestfs_h *g); This returns the current out of memory handler. API CALLS
guestfs_add_cdrom int guestfs_add_cdrom (guestfs_h *g, const char *filename); This function is deprecated. In new code, use the "guestfs_add_drive_opts" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This function adds a virtual CD-ROM disk image to the guest. This is equivalent to the qemu parameter -cdrom filename. Notes: o This call checks for the existence of "filename". This stops you from specifying other types of drive which are supported by qemu such as "nbd:" and "http:" URLs. To specify those, use the general "guestfs_config" call instead. o If you just want to add an ISO file (often you use this as an efficient way to transfer large files into the guest), then you should probably use "guestfs_add_drive_ro" instead. This function returns 0 on success or -1 on error. (Added in 0.3) guestfs_add_domain int guestfs_add_domain (guestfs_h *g, const char *dom, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_ADD_DOMAIN_LIBVIRTURI, const char *libvirturi, GUESTFS_ADD_DOMAIN_READONLY, int readonly, GUESTFS_ADD_DOMAIN_IFACE, const char *iface, GUESTFS_ADD_DOMAIN_LIVE, int live, GUESTFS_ADD_DOMAIN_ALLOWUUID, int allowuuid, GUESTFS_ADD_DOMAIN_READONLYDISK, const char *readonlydisk, This function adds the disk(s) attached to the named libvirt domain "dom". It works by connecting to libvirt, requesting the domain and domain XML from libvirt, parsing it for disks, and calling "guestfs_add_drive_opts" on each one. The number of disks added is returned. This operation is atomic: if an error is returned, then no disks are added. This function does some minimal checks to make sure the libvirt domain is not running (unless "readonly" is true). In a future version we will try to acquire the libvirt lock on each disk. Disks must be accessible locally. This often means that adding disks from a remote libvirt connection (see <http://libvirt.org/remote.html>) will fail unless those disks are accessible via the same device path locally too. The optional "libvirturi" parameter sets the libvirt URI (see <http://libvirt.org/uri.html>). If this is not set then we connect to the default libvirt URI (or one set through an environment variable, see the libvirt documentation for full details). The optional "live" flag controls whether this call will try to connect to a running virtual machine "guestfsd" process if it sees a suitable <channel> element in the libvirt XML definition. The default (if the flag is omitted) is never to try. See "ATTACHING TO RUNNING DAEMONS" in guestfs(3) for more information. If the "allowuuid" flag is true (default is false) then a UUID may be passed instead of the domain name. The "dom" string is treated as a UUID first and looked up, and if that lookup fails then we treat "dom" as a name as usual. The optional "readonlydisk" parameter controls what we do for disks which are marked <readonly/> in the libvirt XML. Possible values are: readonlydisk = "error" If "readonly" is false: The whole call is aborted with an error if any disk with the <readonly/> flag is found. If "readonly" is true: Disks with the <readonly/> flag are added read-only. readonlydisk = "read" If "readonly" is false: Disks with the <readonly/> flag are added read-only. Other disks are added read/write. If "readonly" is true: Disks with the <readonly/> flag are added read-only. readonlydisk = "write" (default) If "readonly" is false: Disks with the <readonly/> flag are added read/write. If "readonly" is true: Disks with the <readonly/> flag are added read-only. readonlydisk = "ignore" If "readonly" is true or false: Disks with the <readonly/> flag are skipped. The other optional parameters are passed directly through to "guestfs_add_drive_opts". On error this function returns -1. (Added in 1.7.4) guestfs_add_domain_va int guestfs_add_domain_va (guestfs_h *g, const char *dom, va_list args); This is the "va_list variant" of "guestfs_add_domain". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_add_domain_argv int guestfs_add_domain_argv (guestfs_h *g, const char *dom, const struct guestfs_add_domain_argv *optargs); This is the "argv variant" of "guestfs_add_domain". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_add_drive int guestfs_add_drive (guestfs_h *g, const char *filename); This function is the equivalent of calling "guestfs_add_drive_opts" with no optional parameters, so the disk is added writable, with the format being detected automatically. Automatic detection of the format opens you up to a potential security hole when dealing with untrusted raw-format images. See CVE-2010-3851 and RHBZ#642934. Specifying the format closes this security hole. Therefore you should think about replacing calls to this function with calls to "guestfs_add_drive_opts", and specifying the format. This function returns 0 on success or -1 on error. (Added in 0.3) guestfs_add_drive_opts int guestfs_add_drive_opts (guestfs_h *g, const char *filename, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_ADD_DRIVE_OPTS_READONLY, int readonly, GUESTFS_ADD_DRIVE_OPTS_FORMAT, const char *format, GUESTFS_ADD_DRIVE_OPTS_IFACE, const char *iface, GUESTFS_ADD_DRIVE_OPTS_NAME, const char *name, This function adds a virtual machine disk image "filename" to libguestfs. The first time you call this function, the disk appears as "/dev/sda", the second time as "/dev/sdb", and so on. You don't necessarily need to be root when using libguestfs. However you obviously do need sufficient permissions to access the filename for whatever operations you want to perform (ie. read access if you just want to read the image or write access if you want to modify the image). This call checks that "filename" exists. The optional arguments are: "readonly" If true then the image is treated as read-only. Writes are still allowed, but they are stored in a temporary snapshot overlay which is discarded at the end. The disk that you add is not modified. "format" This forces the image format. If you omit this (or use "guestfs_add_drive" or "guestfs_add_drive_ro") then the format is automatically detected. Possible formats include "raw" and "qcow2". Automatic detection of the format opens you up to a potential security hole when dealing with untrusted raw-format images. See CVE-2010-3851 and RHBZ#642934. Specifying the format closes this security hole. "iface" This rarely-used option lets you emulate the behaviour of the deprecated "guestfs_add_drive_with_if" call (q.v.) "name" The name the drive had in the original guest, e.g. /dev/sdb. This is used as a hint to the guest inspection process if it is available. This function returns 0 on success or -1 on error. (Added in 1.5.23) guestfs_add_drive_opts_va int guestfs_add_drive_opts_va (guestfs_h *g, const char *filename, va_list args); This is the "va_list variant" of "guestfs_add_drive_opts". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_add_drive_opts_argv int guestfs_add_drive_opts_argv (guestfs_h *g, const char *filename, const struct guestfs_add_drive_opts_argv *optargs); This is the "argv variant" of "guestfs_add_drive_opts". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_add_drive_ro int guestfs_add_drive_ro (guestfs_h *g, const char *filename); This function is the equivalent of calling "guestfs_add_drive_opts" with the optional parameter "GUESTFS_ADD_DRIVE_OPTS_READONLY" set to 1, so the disk is added read-only, with the format being detected automatically. This function returns 0 on success or -1 on error. (Added in 1.0.38) guestfs_add_drive_ro_with_if int guestfs_add_drive_ro_with_if (guestfs_h *g, const char *filename, const char *iface); This function is deprecated. In new code, use the "guestfs_add_drive_opts" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This is the same as "guestfs_add_drive_ro" but it allows you to specify the QEMU interface emulation to use at run time. This function returns 0 on success or -1 on error. (Added in 1.0.84) guestfs_add_drive_with_if int guestfs_add_drive_with_if (guestfs_h *g, const char *filename, const char *iface); This function is deprecated. In new code, use the "guestfs_add_drive_opts" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This is the same as "guestfs_add_drive" but it allows you to specify the QEMU interface emulation to use at run time. This function returns 0 on success or -1 on error. (Added in 1.0.84) guestfs_aug_clear int guestfs_aug_clear (guestfs_h *g, const char *augpath); Set the value associated with "path" to "NULL". This is the same as the augtool(1) "clear" command. This function returns 0 on success or -1 on error. (Added in 1.3.4) guestfs_aug_close int guestfs_aug_close (guestfs_h *g); Close the current Augeas handle and free up any resources used by it. After calling this, you have to call "guestfs_aug_init" again before you can use any other Augeas functions. This function returns 0 on success or -1 on error. (Added in 0.7) guestfs_aug_defnode struct guestfs_int_bool * guestfs_aug_defnode (guestfs_h *g, const char *name, const char *expr, const char *val); Defines a variable "name" whose value is the result of evaluating "expr". If "expr" evaluates to an empty nodeset, a node is created, equivalent to calling "guestfs_aug_set" "expr", "value". "name" will be the nodeset containing that single node. On success this returns a pair containing the number of nodes in the nodeset, and a boolean flag if a node was created. This function returns a "struct guestfs_int_bool *", or NULL if there was an error. The caller must call "guestfs_free_int_bool" after use. (Added in 0.7) guestfs_aug_defvar int guestfs_aug_defvar (guestfs_h *g, const char *name, const char *expr); Defines an Augeas variable "name" whose value is the result of evaluating "expr". If "expr" is NULL, then "name" is undefined. On success this returns the number of nodes in "expr", or 0 if "expr" evaluates to something which is not a nodeset. On error this function returns -1. (Added in 0.7) guestfs_aug_get char * guestfs_aug_get (guestfs_h *g, const char *augpath); Look up the value associated with "path". If "path" matches exactly one node, the "value" is returned. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 0.7) guestfs_aug_init int guestfs_aug_init (guestfs_h *g, const char *root, int flags); Create a new Augeas handle for editing configuration files. If there was any previous Augeas handle associated with this guestfs session, then it is closed. You must call this before using any other "guestfs_aug_*" commands. "root" is the filesystem root. "root" must not be NULL, use "/" instead. The flags are the same as the flags defined in <augeas.h>, the logical or of the following integers: "AUG_SAVE_BACKUP" = 1 Keep the original file with a ".augsave" extension. "AUG_SAVE_NEWFILE" = 2 Save changes into a file with extension ".augnew", and do not overwrite original. Overrides "AUG_SAVE_BACKUP". "AUG_TYPE_CHECK" = 4 Typecheck lenses. This option is only useful when debugging Augeas lenses. Use of this option may require additional memory for the libguestfs appliance. You may need to set the "LIBGUESTFS_MEMSIZE" environment variable or call "guestfs_set_memsize". "AUG_NO_STDINC" = 8 Do not use standard load path for modules. "AUG_SAVE_NOOP" = 16 Make save a no-op, just record what would have been changed. "AUG_NO_LOAD" = 32 Do not load the tree in "guestfs_aug_init". To close the handle, you can call "guestfs_aug_close". To find out more about Augeas, see <http://augeas.net/>. This function returns 0 on success or -1 on error. (Added in 0.7) guestfs_aug_insert int guestfs_aug_insert (guestfs_h *g, const char *augpath, const char *label, int before); Create a new sibling "label" for "path", inserting it into the tree before or after "path" (depending on the boolean flag "before"). "path" must match exactly one existing node in the tree, and "label" must be a label, ie. not contain "/", "*" or end with a bracketed index "[N]". This function returns 0 on success or -1 on error. (Added in 0.7) guestfs_aug_load int guestfs_aug_load (guestfs_h *g); Load files into the tree. See "aug_load" in the Augeas documentation for the full gory details. This function returns 0 on success or -1 on error. (Added in 0.7) guestfs_aug_ls char ** guestfs_aug_ls (guestfs_h *g, const char *augpath); This is just a shortcut for listing "guestfs_aug_match" "path/*" and sorting the resulting nodes into alphabetical order. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 0.8) guestfs_aug_match char ** guestfs_aug_match (guestfs_h *g, const char *augpath); Returns a list of paths which match the path expression "path". The returned paths are sufficiently qualified so that they match exactly one node in the current tree. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 0.7) guestfs_aug_mv int guestfs_aug_mv (guestfs_h *g, const char *src, const char *dest); Move the node "src" to "dest". "src" must match exactly one node. "dest" is overwritten if it exists. This function returns 0 on success or -1 on error. (Added in 0.7) guestfs_aug_rm int guestfs_aug_rm (guestfs_h *g, const char *augpath); Remove "path" and all of its children. On success this returns the number of entries which were removed. On error this function returns -1. (Added in 0.7) guestfs_aug_save int guestfs_aug_save (guestfs_h *g); This writes all pending changes to disk. The flags which were passed to "guestfs_aug_init" affect exactly how files are saved. This function returns 0 on success or -1 on error. (Added in 0.7) guestfs_aug_set int guestfs_aug_set (guestfs_h *g, const char *augpath, const char *val); Set the value associated with "path" to "val". In the Augeas API, it is possible to clear a node by setting the value to NULL. Due to an oversight in the libguestfs API you cannot do that with this call. Instead you must use the "guestfs_aug_clear" call. This function returns 0 on success or -1 on error. (Added in 0.7) guestfs_available int guestfs_available (guestfs_h *g, char *const *groups); This command is used to check the availability of some groups of functionality in the appliance, which not all builds of the libguestfs appliance will be able to provide. The libguestfs groups, and the functions that those groups correspond to, are listed in "AVAILABILITY" in guestfs(3). You can also fetch this list at runtime by calling "guestfs_available_all_groups". The argument "groups" is a list of group names, eg: "["inotify", "augeas"]" would check for the availability of the Linux inotify functions and Augeas (configuration file editing) functions. The command returns no error if all requested groups are available. It fails with an error if one or more of the requested groups is unavailable in the appliance. If an unknown group name is included in the list of groups then an error is always returned. Notes: o You must call "guestfs_launch" before calling this function. The reason is because we don't know what groups are supported by the appliance/daemon until it is running and can be queried. o If a group of functions is available, this does not necessarily mean that they will work. You still have to check for errors when calling individual API functions even if they are available. o It is usually the job of distro packagers to build complete functionality into the libguestfs appliance. Upstream libguestfs, if built from source with all requirements satisfied, will support everything. o This call was added in version 1.0.80. In previous versions of libguestfs all you could do would be to speculatively execute a command to find out if the daemon implemented it. See also "guestfs_version". This function returns 0 on success or -1 on error. (Added in 1.0.80) guestfs_available_all_groups char ** guestfs_available_all_groups (guestfs_h *g); This command returns a list of all optional groups that this daemon knows about. Note this returns both supported and unsupported groups. To find out which ones the daemon can actually support you have to call "guestfs_available" on each member of the returned list. See also "guestfs_available" and "AVAILABILITY" in guestfs(3). This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.3.15) guestfs_base64_in int guestfs_base64_in (guestfs_h *g, const char *base64file, const char *filename); This command uploads base64-encoded data from "base64file" to "filename". This function returns 0 on success or -1 on error. (Added in 1.3.5) guestfs_base64_out int guestfs_base64_out (guestfs_h *g, const char *filename, const char *base64file); This command downloads the contents of "filename", writing it out to local file "base64file" encoded as base64. This function returns 0 on success or -1 on error. (Added in 1.3.5) guestfs_blkid char ** guestfs_blkid (guestfs_h *g, const char *device); This command returns block device attributes for "device". The following fields are usually present in the returned hash. Other fields may also be present. "UUID" The uuid of this device. "LABEL" The label of this device. "VERSION" The version of blkid command. "TYPE" The filesystem type or RAID of this device. "USAGE" The usage of this device, for example "filesystem" or "raid". This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use. (Added in 1.15.9) guestfs_blockdev_flushbufs int guestfs_blockdev_flushbufs (guestfs_h *g, const char *device); This tells the kernel to flush internal buffers associated with "device". This uses the blockdev(8) command. This function returns 0 on success or -1 on error. (Added in 0.9.3) guestfs_blockdev_getbsz int guestfs_blockdev_getbsz (guestfs_h *g, const char *device); This returns the block size of a device. (Note this is different from both size in blocks and filesystem block size). This uses the blockdev(8) command. On error this function returns -1. (Added in 0.9.3) guestfs_blockdev_getro int guestfs_blockdev_getro (guestfs_h *g, const char *device); Returns a boolean indicating if the block device is read-only (true if read-only, false if not). This uses the blockdev(8) command. This function returns a C truth value on success or -1 on error. (Added in 0.9.3) guestfs_blockdev_getsize64 int64_t guestfs_blockdev_getsize64 (guestfs_h *g, const char *device); This returns the size of the device in bytes. See also "guestfs_blockdev_getsz". This uses the blockdev(8) command. On error this function returns -1. (Added in 0.9.3) guestfs_blockdev_getss int guestfs_blockdev_getss (guestfs_h *g, const char *device); This returns the size of sectors on a block device. Usually 512, but can be larger for modern devices. (Note, this is not the size in sectors, use "guestfs_blockdev_getsz" for that). This uses the blockdev(8) command. On error this function returns -1. (Added in 0.9.3) guestfs_blockdev_getsz int64_t guestfs_blockdev_getsz (guestfs_h *g, const char *device); This returns the size of the device in units of 512-byte sectors (even if the sectorsize isn't 512 bytes ... weird). See also "guestfs_blockdev_getss" for the real sector size of the device, and "guestfs_blockdev_getsize64" for the more useful size in bytes. This uses the blockdev(8) command. On error this function returns -1. (Added in 0.9.3) guestfs_blockdev_rereadpt int guestfs_blockdev_rereadpt (guestfs_h *g, const char *device); Reread the partition table on "device". This uses the blockdev(8) command. This function returns 0 on success or -1 on error. (Added in 0.9.3) guestfs_blockdev_setbsz int guestfs_blockdev_setbsz (guestfs_h *g, const char *device, int blocksize); This sets the block size of a device. (Note this is different from both size in blocks and filesystem block size). This uses the blockdev(8) command. This function returns 0 on success or -1 on error. (Added in 0.9.3) guestfs_blockdev_setro int guestfs_blockdev_setro (guestfs_h *g, const char *device); Sets the block device named "device" to read-only. This uses the blockdev(8) command. This function returns 0 on success or -1 on error. (Added in 0.9.3) guestfs_blockdev_setrw int guestfs_blockdev_setrw (guestfs_h *g, const char *device); Sets the block device named "device" to read-write. This uses the blockdev(8) command. This function returns 0 on success or -1 on error. (Added in 0.9.3) guestfs_btrfs_device_add int guestfs_btrfs_device_add (guestfs_h *g, char *const *devices, const char *fs); Add the list of device(s) in "devices" to the btrfs filesystem mounted at "fs". If "devices" is an empty list, this does nothing. This function returns 0 on success or -1 on error. (Added in 1.17.35) guestfs_btrfs_device_delete int guestfs_btrfs_device_delete (guestfs_h *g, char *const *devices, const char *fs); Remove the "devices" from the btrfs filesystem mounted at "fs". If "devices" is an empty list, this does nothing. This function returns 0 on success or -1 on error. (Added in 1.17.35) guestfs_btrfs_filesystem_balance int guestfs_btrfs_filesystem_balance (guestfs_h *g, const char *fs); Balance the chunks in the btrfs filesystem mounted at "fs" across the underlying devices. This function returns 0 on success or -1 on error. (Added in 1.17.35) guestfs_btrfs_filesystem_resize int guestfs_btrfs_filesystem_resize (guestfs_h *g, const char *mountpoint, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_BTRFS_FILESYSTEM_RESIZE_SIZE, int64_t size, This command resizes a btrfs filesystem. Note that unlike other resize calls, the filesystem has to be mounted and the parameter is the mountpoint not the device (this is a requirement of btrfs itself). The optional parameters are: "size" The new size (in bytes) of the filesystem. If omitted, the filesystem is resized to the maximum size. See also btrfs(8). This function returns 0 on success or -1 on error. (Added in 1.11.17) guestfs_btrfs_filesystem_resize_va int guestfs_btrfs_filesystem_resize_va (guestfs_h *g, const char *mountpoint, va_list args); This is the "va_list variant" of "guestfs_btrfs_filesystem_resize". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_btrfs_filesystem_resize_argv int guestfs_btrfs_filesystem_resize_argv (guestfs_h *g, const char *mountpoint, const struct guestfs_btrfs_filesystem_resize_argv *optargs); This is the "argv variant" of "guestfs_btrfs_filesystem_resize". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_btrfs_filesystem_sync int guestfs_btrfs_filesystem_sync (guestfs_h *g, const char *fs); Force sync on the btrfs filesystem mounted at "fs". This function returns 0 on success or -1 on error. (Added in 1.17.35) guestfs_btrfs_fsck int guestfs_btrfs_fsck (guestfs_h *g, const char *device, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_BTRFS_FSCK_SUPERBLOCK, int64_t superblock, GUESTFS_BTRFS_FSCK_REPAIR, int repair, Used to check a btrfs filesystem, "device" is the device file where the filesystem is stored. This function returns 0 on success or -1 on error. (Added in 1.17.43) guestfs_btrfs_fsck_va int guestfs_btrfs_fsck_va (guestfs_h *g, const char *device, va_list args); This is the "va_list variant" of "guestfs_btrfs_fsck". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_btrfs_fsck_argv int guestfs_btrfs_fsck_argv (guestfs_h *g, const char *device, const struct guestfs_btrfs_fsck_argv *optargs); This is the "argv variant" of "guestfs_btrfs_fsck". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_btrfs_set_seeding int guestfs_btrfs_set_seeding (guestfs_h *g, const char *device, int seeding); Enable or disable the seeding feature of a device that contains a btrfs filesystem. This function returns 0 on success or -1 on error. (Added in 1.17.43) guestfs_btrfs_subvolume_create int guestfs_btrfs_subvolume_create (guestfs_h *g, const char *dest); Create a btrfs subvolume. The "dest" argument is the destination directory and the name of the snapshot, in the form "/path/to/dest/name". This function returns 0 on success or -1 on error. (Added in 1.17.35) guestfs_btrfs_subvolume_delete int guestfs_btrfs_subvolume_delete (guestfs_h *g, const char *subvolume); Delete the named btrfs subvolume. This function returns 0 on success or -1 on error. (Added in 1.17.35) guestfs_btrfs_subvolume_list struct guestfs_btrfssubvolume_list * guestfs_btrfs_subvolume_list (guestfs_h *g, const char *fs); List the btrfs snapshots and subvolumes of the btrfs filesystem which is mounted at "fs". This function returns a "struct guestfs_btrfssubvolume_list *", or NULL if there was an error. The caller must call "guestfs_free_btrfssubvolume_list" after use. (Added in 1.17.35) guestfs_btrfs_subvolume_set_default int guestfs_btrfs_subvolume_set_default (guestfs_h *g, int64_t id, const char *fs); Set the subvolume of the btrfs filesystem "fs" which will be mounted by default. See "guestfs_btrfs_subvolume_list" to get a list of subvolumes. This function returns 0 on success or -1 on error. (Added in 1.17.35) guestfs_btrfs_subvolume_snapshot int guestfs_btrfs_subvolume_snapshot (guestfs_h *g, const char *source, const char *dest); Create a writable snapshot of the btrfs subvolume "source". The "dest" argument is the destination directory and the name of the snapshot, in the form "/path/to/dest/name". This function returns 0 on success or -1 on error. (Added in 1.17.35) guestfs_case_sensitive_path char * guestfs_case_sensitive_path (guestfs_h *g, const char *path); This can be used to resolve case insensitive paths on a filesystem which is case sensitive. The use case is to resolve paths which you have read from Windows configuration files or the Windows Registry, to the true path. The command handles a peculiarity of the Linux ntfs-3g filesystem driver (and probably others), which is that although the underlying filesystem is case-insensitive, the driver exports the filesystem to Linux as case-sensitive. One consequence of this is that special directories such as "c:windows" may appear as "/WINDOWS" or "/windows" (or other things) depending on the precise details of how they were created. In Windows itself this would not be a problem. Bug or feature? You decide: http://www.tuxera.com/community/ntfs-3g-faq/#posixfilenames1 <http://www.tuxera.com/community/ntfs-3g- faq/#posixfilenames1> This function resolves the true case of each element in the path and returns the case-sensitive path. Thus "guestfs_case_sensitive_path" ("/Windows/System32") might return "/WINDOWS/system32" (the exact return value would depend on details of how the directories were originally created under Windows). Note: This function does not handle drive names, backslashes etc. See also "guestfs_realpath". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.75) guestfs_cat char * guestfs_cat (guestfs_h *g, const char *path); Return the contents of the file named "path". Note that this function cannot correctly handle binary files (specifically, files containing "" character which is treated as end of string). For those you need to use the "guestfs_read_file" or "guestfs_download" functions which have a more complex interface. This function returns a string, or NULL on error. The caller must free the returned string after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 0.4) guestfs_checksum char * guestfs_checksum (guestfs_h *g, const char *csumtype, const char *path); This call computes the MD5, SHAx or CRC checksum of the file named "path". The type of checksum to compute is given by the "csumtype" parameter which must have one of the following values: "crc" Compute the cyclic redundancy check (CRC) specified by POSIX for the "cksum" command. "md5" Compute the MD5 hash (using the "md5sum" program). "sha1" Compute the SHA1 hash (using the "sha1sum" program). "sha224" Compute the SHA224 hash (using the "sha224sum" program). "sha256" Compute the SHA256 hash (using the "sha256sum" program). "sha384" Compute the SHA384 hash (using the "sha384sum" program). "sha512" Compute the SHA512 hash (using the "sha512sum" program). The checksum is returned as a printable string. To get the checksum for a device, use "guestfs_checksum_device". To get the checksums for many files, use "guestfs_checksums_out". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.2) guestfs_checksum_device char * guestfs_checksum_device (guestfs_h *g, const char *csumtype, const char *device); This call computes the MD5, SHAx or CRC checksum of the contents of the device named "device". For the types of checksums supported see the "guestfs_checksum" command. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.3.2) guestfs_checksums_out int guestfs_checksums_out (guestfs_h *g, const char *csumtype, const char *directory, const char *sumsfile); This command computes the checksums of all regular files in "directory" and then emits a list of those checksums to the local output file "sumsfile". This can be used for verifying the integrity of a virtual machine. However to be properly secure you should pay attention to the output of the checksum command (it uses the ones from GNU coreutils). In particular when the filename is not printable, coreutils uses a special backslash syntax. For more information, see the GNU coreutils info file. This function returns 0 on success or -1 on error. (Added in 1.3.7) guestfs_chmod int guestfs_chmod (guestfs_h *g, int mode, const char *path); Change the mode (permissions) of "path" to "mode". Only numeric modes are supported. Note: When using this command from guestfish, "mode" by default would be decimal, unless you prefix it with 0 to get octal, ie. use 0700 not 700. The mode actually set is affected by the umask. This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_chown int guestfs_chown (guestfs_h *g, int owner, int group, const char *path); Change the file owner to "owner" and group to "group". Only numeric uid and gid are supported. If you want to use names, you will need to locate and parse the password file yourself (Augeas support makes this relatively easy). This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_command char * guestfs_command (guestfs_h *g, char *const *arguments); This call runs a command from the guest filesystem. The filesystem must be mounted, and must contain a compatible operating system (ie. something Linux, with the same or compatible processor architecture). The single parameter is an argv-style list of arguments. The first element is the name of the program to run. Subsequent elements are parameters. The list must be non-empty (ie. must contain a program name). Note that the command runs directly, and is not invoked via the shell (see "guestfs_sh"). The return value is anything printed to stdout by the command. If the command returns a non-zero exit status, then this function returns an error message. The error message string is the content of stderr from the command. The $PATH environment variable will contain at least "/usr/bin" and "/bin". If you require a program from another location, you should provide the full path in the first parameter. Shared libraries and data files required by the program must be available on filesystems which are mounted in the correct places. It is the caller's responsibility to ensure all filesystems that are needed are mounted at the right locations. This function returns a string, or NULL on error. The caller must free the returned string after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 0.9.1) guestfs_command_lines char ** guestfs_command_lines (guestfs_h *g, char *const *arguments); This is the same as "guestfs_command", but splits the result into a list of lines. See also: "guestfs_sh_lines" This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 0.9.1) guestfs_compress_device_out int guestfs_compress_device_out (guestfs_h *g, const char *ctype, const char *device, const char *zdevice, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_COMPRESS_DEVICE_OUT_LEVEL, int level, This command compresses "device" and writes it out to the local file "zdevice". The "ctype" and optional "level" parameters have the same meaning as in "guestfs_compress_out". This function returns 0 on success or -1 on error. (Added in 1.13.15) guestfs_compress_device_out_va int guestfs_compress_device_out_va (guestfs_h *g, const char *ctype, const char *device, const char *zdevice, va_list args); This is the "va_list variant" of "guestfs_compress_device_out". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_compress_device_out_argv int guestfs_compress_device_out_argv (guestfs_h *g, const char *ctype, const char *device, const char *zdevice, const struct guestfs_compress_device_out_argv *optargs); This is the "argv variant" of "guestfs_compress_device_out". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_compress_out int guestfs_compress_out (guestfs_h *g, const char *ctype, const char *file, const char *zfile, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_COMPRESS_OUT_LEVEL, int level, This command compresses "file" and writes it out to the local file "zfile". The compression program used is controlled by the "ctype" parameter. Currently this includes: "compress", "gzip", "bzip2", "xz" or "lzop". Some compression types may not be supported by particular builds of libguestfs, in which case you will get an error containing the substring "not supported". The optional "level" parameter controls compression level. The meaning and default for this parameter depends on the compression program being used. This function returns 0 on success or -1 on error. (Added in 1.13.15) guestfs_compress_out_va int guestfs_compress_out_va (guestfs_h *g, const char *ctype, const char *file, const char *zfile, va_list args); This is the "va_list variant" of "guestfs_compress_out". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_compress_out_argv int guestfs_compress_out_argv (guestfs_h *g, const char *ctype, const char *file, const char *zfile, const struct guestfs_compress_out_argv *optargs); This is the "argv variant" of "guestfs_compress_out". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_config int guestfs_config (guestfs_h *g, const char *qemuparam, const char *qemuvalue); This can be used to add arbitrary qemu command line parameters of the form -param value. Actually it's not quite arbitrary - we prevent you from setting some parameters which would interfere with parameters that we use. The first character of "param" string must be a "-" (dash). "value" can be NULL. This function returns 0 on success or -1 on error. (Added in 0.3) guestfs_copy_device_to_device int guestfs_copy_device_to_device (guestfs_h *g, const char *src, const char *dest, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_COPY_DEVICE_TO_DEVICE_SRCOFFSET, int64_t srcoffset, GUESTFS_COPY_DEVICE_TO_DEVICE_DESTOFFSET, int64_t destoffset, GUESTFS_COPY_DEVICE_TO_DEVICE_SIZE, int64_t size, The four calls "guestfs_copy_device_to_device", "guestfs_copy_device_to_file", "guestfs_copy_file_to_device", and "guestfs_copy_file_to_file" let you copy from a source (device|file) to a destination (device|file). Partial copies can be made since you can specify optionally the source offset, destination offset and size to copy. These values are all specified in bytes. If not given, the offsets both default to zero, and the size defaults to copying as much as possible until we hit the end of the source. The source and destination may be the same object. However overlapping regions may not be copied correctly. If the destination is a file, it is created if required. If the destination file is not large enough, it is extended. This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.13.25) guestfs_copy_device_to_device_va int guestfs_copy_device_to_device_va (guestfs_h *g, const char *src, const char *dest, va_list args); This is the "va_list variant" of "guestfs_copy_device_to_device". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_copy_device_to_device_argv int guestfs_copy_device_to_device_argv (guestfs_h *g, const char *src, const char *dest, const struct guestfs_copy_device_to_device_argv *optargs); This is the "argv variant" of "guestfs_copy_device_to_device". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_copy_device_to_file int guestfs_copy_device_to_file (guestfs_h *g, const char *src, const char *dest, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_COPY_DEVICE_TO_FILE_SRCOFFSET, int64_t srcoffset, GUESTFS_COPY_DEVICE_TO_FILE_DESTOFFSET, int64_t destoffset, GUESTFS_COPY_DEVICE_TO_FILE_SIZE, int64_t size, See "guestfs_copy_device_to_device" for a general overview of this call. This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.13.25) guestfs_copy_device_to_file_va int guestfs_copy_device_to_file_va (guestfs_h *g, const char *src, const char *dest, va_list args); This is the "va_list variant" of "guestfs_copy_device_to_file". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_copy_device_to_file_argv int guestfs_copy_device_to_file_argv (guestfs_h *g, const char *src, const char *dest, const struct guestfs_copy_device_to_file_argv *optargs); This is the "argv variant" of "guestfs_copy_device_to_file". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_copy_file_to_device int guestfs_copy_file_to_device (guestfs_h *g, const char *src, const char *dest, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_COPY_FILE_TO_DEVICE_SRCOFFSET, int64_t srcoffset, GUESTFS_COPY_FILE_TO_DEVICE_DESTOFFSET, int64_t destoffset, GUESTFS_COPY_FILE_TO_DEVICE_SIZE, int64_t size, See "guestfs_copy_device_to_device" for a general overview of this call. This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.13.25) guestfs_copy_file_to_device_va int guestfs_copy_file_to_device_va (guestfs_h *g, const char *src, const char *dest, va_list args); This is the "va_list variant" of "guestfs_copy_file_to_device". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_copy_file_to_device_argv int guestfs_copy_file_to_device_argv (guestfs_h *g, const char *src, const char *dest, const struct guestfs_copy_file_to_device_argv *optargs); This is the "argv variant" of "guestfs_copy_file_to_device". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_copy_file_to_file int guestfs_copy_file_to_file (guestfs_h *g, const char *src, const char *dest, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_COPY_FILE_TO_FILE_SRCOFFSET, int64_t srcoffset, GUESTFS_COPY_FILE_TO_FILE_DESTOFFSET, int64_t destoffset, GUESTFS_COPY_FILE_TO_FILE_SIZE, int64_t size, See "guestfs_copy_device_to_device" for a general overview of this call. This is not the function you want for copying files. This is for copying blocks within existing files. See "guestfs_cp", "guestfs_cp_a" and "guestfs_mv" for general file copying and moving functions. This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.13.25) guestfs_copy_file_to_file_va int guestfs_copy_file_to_file_va (guestfs_h *g, const char *src, const char *dest, va_list args); This is the "va_list variant" of "guestfs_copy_file_to_file". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_copy_file_to_file_argv int guestfs_copy_file_to_file_argv (guestfs_h *g, const char *src, const char *dest, const struct guestfs_copy_file_to_file_argv *optargs); This is the "argv variant" of "guestfs_copy_file_to_file". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_copy_size int guestfs_copy_size (guestfs_h *g, const char *src, const char *dest, int64_t size); This function is deprecated. In new code, use the "guestfs_copy_device_to_device" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This command copies exactly "size" bytes from one source device or file "src" to another destination device or file "dest". Note this will fail if the source is too short or if the destination is not large enough. This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.0.87) guestfs_cp int guestfs_cp (guestfs_h *g, const char *src, const char *dest); This copies a file from "src" to "dest" where "dest" is either a destination filename or destination directory. This function returns 0 on success or -1 on error. (Added in 1.0.18) guestfs_cp_a int guestfs_cp_a (guestfs_h *g, const char *src, const char *dest); This copies a file or directory from "src" to "dest" recursively using the "cp -a" command. This function returns 0 on success or -1 on error. (Added in 1.0.18) guestfs_dd int guestfs_dd (guestfs_h *g, const char *src, const char *dest); This function is deprecated. In new code, use the "guestfs_copy_device_to_device" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This command copies from one source device or file "src" to another destination device or file "dest". Normally you would use this to copy to or from a device or partition, for example to duplicate a filesystem. If the destination is a device, it must be as large or larger than the source file or device, otherwise the copy will fail. This command cannot do partial copies (see "guestfs_copy_device_to_device"). This function returns 0 on success or -1 on error. (Added in 1.0.80) guestfs_df char * guestfs_df (guestfs_h *g); This command runs the "df" command to report disk space used. This command is mostly useful for interactive sessions. It is not intended that you try to parse the output string. Use "guestfs_statvfs" from programs. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.54) guestfs_df_h char * guestfs_df_h (guestfs_h *g); This command runs the "df -h" command to report disk space used in human-readable format. This command is mostly useful for interactive sessions. It is not intended that you try to parse the output string. Use "guestfs_statvfs" from programs. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.54) guestfs_dmesg char * guestfs_dmesg (guestfs_h *g); This returns the kernel messages ("dmesg" output) from the guest kernel. This is sometimes useful for extended debugging of problems. Another way to get the same information is to enable verbose messages with "guestfs_set_verbose" or by setting the environment variable "LIBGUESTFS_DEBUG=1" before running the program. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.18) guestfs_download int guestfs_download (guestfs_h *g, const char *remotefilename, const char *filename); Download file "remotefilename" and save it as "filename" on the local machine. "filename" can also be a named pipe. See also "guestfs_upload", "guestfs_cat". This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.0.2) guestfs_download_offset int guestfs_download_offset (guestfs_h *g, const char *remotefilename, const char *filename, int64_t offset, int64_t size); Download file "remotefilename" and save it as "filename" on the local machine. "remotefilename" is read for "size" bytes starting at "offset" (this region must be within the file or device). Note that there is no limit on the amount of data that can be downloaded with this call, unlike with "guestfs_pread", and this call always reads the full amount unless an error occurs. See also "guestfs_download", "guestfs_pread". This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.5.17) guestfs_drop_caches int guestfs_drop_caches (guestfs_h *g, int whattodrop); This instructs the guest kernel to drop its page cache, and/or dentries and inode caches. The parameter "whattodrop" tells the kernel what precisely to drop, see http://linux-mm.org/Drop_Caches <http://linux-mm.org/Drop_Caches> Setting "whattodrop" to 3 should drop everything. This automatically calls sync(2) before the operation, so that the maximum guest memory is freed. This function returns 0 on success or -1 on error. (Added in 1.0.18) guestfs_du int64_t guestfs_du (guestfs_h *g, const char *path); This command runs the "du -s" command to estimate file space usage for "path". "path" can be a file or a directory. If "path" is a directory then the estimate includes the contents of the directory and all subdirectories (recursively). The result is the estimated size in kilobytes (ie. units of 1024 bytes). On error this function returns -1. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.0.54) guestfs_e2fsck int guestfs_e2fsck (guestfs_h *g, const char *device, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_E2FSCK_CORRECT, int correct, GUESTFS_E2FSCK_FORCEALL, int forceall, This runs the ext2/ext3 filesystem checker on "device". It can take the following optional arguments: "correct" Automatically repair the file system. This option will cause e2fsck to automatically fix any filesystem problems that can be safely fixed without human intervention. This option may not be specified at the same time as the "forceall" option. "forceall" Assume an answer of 'yes' to all questions; allows e2fsck to be used non-interactively. This option may not be specified at the same time as the "correct" option. This function returns 0 on success or -1 on error. (Added in 1.15.17) guestfs_e2fsck_va int guestfs_e2fsck_va (guestfs_h *g, const char *device, va_list args); This is the "va_list variant" of "guestfs_e2fsck". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_e2fsck_argv int guestfs_e2fsck_argv (guestfs_h *g, const char *device, const struct guestfs_e2fsck_argv *optargs); This is the "argv variant" of "guestfs_e2fsck". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_e2fsck_f int guestfs_e2fsck_f (guestfs_h *g, const char *device); This function is deprecated. In new code, use the "guestfs_e2fsck" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This runs "e2fsck -p -f device", ie. runs the ext2/ext3 filesystem checker on "device", noninteractively (-p), even if the filesystem appears to be clean (-f). This function returns 0 on success or -1 on error. (Added in 1.0.29) guestfs_echo_daemon char * guestfs_echo_daemon (guestfs_h *g, char *const *words); This command concatenates the list of "words" passed with single spaces between them and returns the resulting string. You can use this command to test the connection through to the daemon. See also "guestfs_ping_daemon". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.69) guestfs_egrep char ** guestfs_egrep (guestfs_h *g, const char *regex, const char *path); This calls the external "egrep" program and returns the matching lines. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.66) guestfs_egrepi char ** guestfs_egrepi (guestfs_h *g, const char *regex, const char *path); This calls the external "egrep -i" program and returns the matching lines. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.66) guestfs_equal int guestfs_equal (guestfs_h *g, const char *file1, const char *file2); This compares the two files "file1" and "file2" and returns true if their content is exactly equal, or false otherwise. The external cmp(1) program is used for the comparison. This function returns a C truth value on success or -1 on error. (Added in 1.0.18) guestfs_exists int guestfs_exists (guestfs_h *g, const char *path); This returns "true" if and only if there is a file, directory (or anything) with the given "path" name. See also "guestfs_is_file", "guestfs_is_dir", "guestfs_stat". This function returns a C truth value on success or -1 on error. (Added in 0.8) guestfs_fallocate int guestfs_fallocate (guestfs_h *g, const char *path, int len); This function is deprecated. In new code, use the "guestfs_fallocate64" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This command preallocates a file (containing zero bytes) named "path" of size "len" bytes. If the file exists already, it is overwritten. Do not confuse this with the guestfish-specific "alloc" command which allocates a file in the host and attaches it as a device. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_fallocate64 int guestfs_fallocate64 (guestfs_h *g, const char *path, int64_t len); This command preallocates a file (containing zero bytes) named "path" of size "len" bytes. If the file exists already, it is overwritten. Note that this call allocates disk blocks for the file. To create a sparse file use "guestfs_truncate_size" instead. The deprecated call "guestfs_fallocate" does the same, but owing to an oversight it only allowed 30 bit lengths to be specified, effectively limiting the maximum size of files created through that call to 1GB. Do not confuse this with the guestfish-specific "alloc" and "sparse" commands which create a file in the host and attach it as a device. This function returns 0 on success or -1 on error. (Added in 1.3.17) guestfs_fgrep char ** guestfs_fgrep (guestfs_h *g, const char *pattern, const char *path); This calls the external "fgrep" program and returns the matching lines. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.66) guestfs_fgrepi char ** guestfs_fgrepi (guestfs_h *g, const char *pattern, const char *path); This calls the external "fgrep -i" program and returns the matching lines. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.66) guestfs_file char * guestfs_file (guestfs_h *g, const char *path); This call uses the standard file(1) command to determine the type or contents of the file. This call will also transparently look inside various types of compressed file. The exact command which runs is "file -zb path". Note in particular that the filename is not prepended to the output (the -b option). The output depends on the output of the underlying file(1) command and it can change in future in ways beyond our control. In other words, the output is not guaranteed by the ABI. See also: file(1), "guestfs_vfs_type", "guestfs_lstat", "guestfs_is_file", "guestfs_is_blockdev" (etc), "guestfs_is_zero". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 0.9.1) guestfs_file_architecture char * guestfs_file_architecture (guestfs_h *g, const char *filename); This detects the architecture of the binary "filename", and returns it if known. Currently defined architectures are: "i386" This string is returned for all 32 bit i386, i486, i586, i686 binaries irrespective of the precise processor requirements of the binary. "x86_64" 64 bit x86-64. "sparc" 32 bit SPARC. "sparc64" 64 bit SPARC V9 and above. "ia64" Intel Itanium. "ppc" 32 bit Power PC. "ppc64" 64 bit Power PC. Libguestfs may return other architecture strings in future. The function works on at least the following types of files: o many types of Un*x and Linux binary o many types of Un*x and Linux shared library o Windows Win32 and Win64 binaries o Windows Win32 and Win64 DLLs Win32 binaries and DLLs return "i386". Win64 binaries and DLLs return "x86_64". o Linux kernel modules o Linux new-style initrd images o some non-x86 Linux vmlinuz kernels What it can't do currently: o static libraries (libfoo.a) o Linux old-style initrd as compressed ext2 filesystem (RHEL 3) o x86 Linux vmlinuz kernels x86 vmlinuz images (bzImage format) consist of a mix of 16-, 32- and compressed code, and are horribly hard to unpack. If you want to find the architecture of a kernel, use the architecture of the associated initrd or kernel module(s) instead. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.5.3) guestfs_filesize int64_t guestfs_filesize (guestfs_h *g, const char *file); This command returns the size of "file" in bytes. To get other stats about a file, use "guestfs_stat", "guestfs_lstat", "guestfs_is_dir", "guestfs_is_file" etc. To get the size of block devices, use "guestfs_blockdev_getsize64". On error this function returns -1. (Added in 1.0.82) guestfs_fill int guestfs_fill (guestfs_h *g, int c, int len, const char *path); This command creates a new file called "path". The initial content of the file is "len" octets of "c", where "c" must be a number in the range "[0..255]". To fill a file with zero bytes (sparsely), it is much more efficient to use "guestfs_truncate_size". To create a file with a pattern of repeating bytes use "guestfs_fill_pattern". This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.0.79) guestfs_fill_pattern int guestfs_fill_pattern (guestfs_h *g, const char *pattern, int len, const char *path); This function is like "guestfs_fill" except that it creates a new file of length "len" containing the repeating pattern of bytes in "pattern". The pattern is truncated if necessary to ensure the length of the file is exactly "len" bytes. This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.3.12) guestfs_find char ** guestfs_find (guestfs_h *g, const char *directory); This command lists out all files and directories, recursively, starting at "directory". It is essentially equivalent to running the shell command "find directory -print" but some post-processing happens on the output, described below. This returns a list of strings without any prefix. Thus if the directory structure was: /tmp/a /tmp/b /tmp/c/d then the returned list from "guestfs_find" "/tmp" would be 4 elements: a b c c/d If "directory" is not a directory, then this command returns an error. The returned list is sorted. See also "guestfs_find0". This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.27) guestfs_find0 int guestfs_find0 (guestfs_h *g, const char *directory, const char *files); This command lists out all files and directories, recursively, starting at "directory", placing the resulting list in the external file called "files". This command works the same way as "guestfs_find" with the following exceptions: o The resulting list is written to an external file. o Items (filenames) in the result are separated by "" characters. See find(1) option -print0. o This command is not limited in the number of names that it can return. o The result list is not sorted. This function returns 0 on success or -1 on error. (Added in 1.0.74) guestfs_findfs_label char * guestfs_findfs_label (guestfs_h *g, const char *label); This command searches the filesystems and returns the one which has the given label. An error is returned if no such filesystem can be found. To find the label of a filesystem, use "guestfs_vfs_label". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.5.3) guestfs_findfs_uuid char * guestfs_findfs_uuid (guestfs_h *g, const char *uuid); This command searches the filesystems and returns the one which has the given UUID. An error is returned if no such filesystem can be found. To find the UUID of a filesystem, use "guestfs_vfs_uuid". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.5.3) guestfs_fsck int guestfs_fsck (guestfs_h *g, const char *fstype, const char *device); This runs the filesystem checker (fsck) on "device" which should have filesystem type "fstype". The returned integer is the status. See fsck(8) for the list of status codes from "fsck". Notes: o Multiple status codes can be summed together. o A non-zero return code can mean "success", for example if errors have been corrected on the filesystem. o Checking or repairing NTFS volumes is not supported (by linux-ntfs). This command is entirely equivalent to running "fsck -a -t fstype device". On error this function returns -1. (Added in 1.0.16) guestfs_get_append const char * guestfs_get_append (guestfs_h *g); Return the additional kernel options which are added to the guest kernel command line. If "NULL" then no options are added. This function returns a string which may be NULL. There is no way to return an error from this function. The string is owned by the guest handle and must not be freed. (Added in 1.0.26) guestfs_get_attach_method char * guestfs_get_attach_method (guestfs_h *g); Return the current attach method. See "guestfs_set_attach_method". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.9.8) guestfs_get_autosync int guestfs_get_autosync (guestfs_h *g); Get the autosync flag. This function returns a C truth value on success or -1 on error. (Added in 0.3) guestfs_get_direct int guestfs_get_direct (guestfs_h *g); Return the direct appliance mode flag. This function returns a C truth value on success or -1 on error. (Added in 1.0.72) guestfs_get_e2attrs char * guestfs_get_e2attrs (guestfs_h *g, const char *file); This returns the file attributes associated with "file". The attributes are a set of bits associated with each inode which affect the behaviour of the file. The attributes are returned as a string of letters (described below). The string may be empty, indicating that no file attributes are set for this file. These attributes are only present when the file is located on an ext2/3/4 filesystem. Using this call on other filesystem types will result in an error. The characters (file attributes) in the returned string are currently: 'A' When the file is accessed, its atime is not modified. 'a' The file is append-only. 'c' The file is compressed on-disk. 'D' (Directories only.) Changes to this directory are written synchronously to disk. 'd' The file is not a candidate for backup (see dump(8)). 'E' The file has compression errors. 'e' The file is using extents. 'h' The file is storing its blocks in units of the filesystem blocksize instead of sectors. 'I' (Directories only.) The directory is using hashed trees. 'i' The file is immutable. It cannot be modified, deleted or renamed. No link can be created to this file. 'j' The file is data-journaled. 's' When the file is deleted, all its blocks will be zeroed. 'S' Changes to this file are written synchronously to disk. 'T' (Directories only.) This is a hint to the block allocator that subdirectories contained in this directory should be spread across blocks. If not present, the block allocator will try to group subdirectories together. 't' For a file, this disables tail-merging. (Not used by upstream implementations of ext2.) 'u' When the file is deleted, its blocks will be saved, allowing the file to be undeleted. 'X' The raw contents of the compressed file may be accessed. 'Z' The compressed file is dirty. More file attributes may be added to this list later. Not all file attributes may be set for all kinds of files. For detailed information, consult the chattr(1) man page. See also "guestfs_set_e2attrs". Don't confuse these attributes with extended attributes (see "guestfs_getxattr"). This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.17.31) guestfs_get_e2generation int64_t guestfs_get_e2generation (guestfs_h *g, const char *file); This returns the ext2 file generation of a file. The generation (which used to be called the "version") is a number associated with an inode. This is most commonly used by NFS servers. The generation is only present when the file is located on an ext2/3/4 filesystem. Using this call on other filesystem types will result in an error. See "guestfs_set_e2generation". On error this function returns -1. (Added in 1.17.31) guestfs_get_e2label char * guestfs_get_e2label (guestfs_h *g, const char *device); This function is deprecated. In new code, use the "guestfs_vfs_label" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This returns the ext2/3/4 filesystem label of the filesystem on "device". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.15) guestfs_get_e2uuid char * guestfs_get_e2uuid (guestfs_h *g, const char *device); This function is deprecated. In new code, use the "guestfs_vfs_uuid" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This returns the ext2/3/4 filesystem UUID of the filesystem on "device". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.15) guestfs_get_memsize int guestfs_get_memsize (guestfs_h *g); This gets the memory size in megabytes allocated to the qemu subprocess. If "guestfs_set_memsize" was not called on this handle, and if "LIBGUESTFS_MEMSIZE" was not set, then this returns the compiled-in default value for memsize. For more information on the architecture of libguestfs, see guestfs(3). On error this function returns -1. (Added in 1.0.55) guestfs_get_network int guestfs_get_network (guestfs_h *g); This returns the enable network flag. This function returns a C truth value on success or -1 on error. (Added in 1.5.4) guestfs_get_path const char * guestfs_get_path (guestfs_h *g); Return the current search path. This is always non-NULL. If it wasn't set already, then this will return the default path. This function returns a string, or NULL on error. The string is owned by the guest handle and must not be freed. (Added in 0.3) guestfs_get_pgroup int guestfs_get_pgroup (guestfs_h *g); This returns the process group flag. This function returns a C truth value on success or -1 on error. (Added in 1.11.18) guestfs_get_pid int guestfs_get_pid (guestfs_h *g); Return the process ID of the qemu subprocess. If there is no qemu subprocess, then this will return an error. This is an internal call used for debugging and testing. On error this function returns -1. (Added in 1.0.56) guestfs_get_qemu const char * guestfs_get_qemu (guestfs_h *g); Return the current qemu binary. This is always non-NULL. If it wasn't set already, then this will return the default qemu binary name. This function returns a string, or NULL on error. The string is owned by the guest handle and must not be freed. (Added in 1.0.6) guestfs_get_recovery_proc int guestfs_get_recovery_proc (guestfs_h *g); Return the recovery process enabled flag. This function returns a C truth value on success or -1 on error. (Added in 1.0.77) guestfs_get_selinux int guestfs_get_selinux (guestfs_h *g); This returns the current setting of the selinux flag which is passed to the appliance at boot time. See "guestfs_set_selinux". For more information on the architecture of libguestfs, see guestfs(3). This function returns a C truth value on success or -1 on error. (Added in 1.0.67) guestfs_get_smp int guestfs_get_smp (guestfs_h *g); This returns the number of virtual CPUs assigned to the appliance. On error this function returns -1. (Added in 1.13.15) guestfs_get_state int guestfs_get_state (guestfs_h *g); This returns the current state as an opaque integer. This is only useful for printing debug and internal error messages. For more information on states, see guestfs(3). On error this function returns -1. (Added in 1.0.2) guestfs_get_trace int guestfs_get_trace (guestfs_h *g); Return the command trace flag. This function returns a C truth value on success or -1 on error. (Added in 1.0.69) guestfs_get_umask int guestfs_get_umask (guestfs_h *g); Return the current umask. By default the umask is 022 unless it has been set by calling "guestfs_umask". On error this function returns -1. (Added in 1.3.4) guestfs_get_verbose int guestfs_get_verbose (guestfs_h *g); This returns the verbose messages flag. This function returns a C truth value on success or -1 on error. (Added in 0.3) guestfs_getcon char * guestfs_getcon (guestfs_h *g); This gets the SELinux security context of the daemon. See the documentation about SELINUX in guestfs(3), and "guestfs_setcon" This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.67) guestfs_getxattr char * guestfs_getxattr (guestfs_h *g, const char *path, const char *name, size_t *size_r); Get a single extended attribute from file "path" named "name". This call follows symlinks. If you want to lookup an extended attribute for the symlink itself, use "guestfs_lgetxattr". Normally it is better to get all extended attributes from a file in one go by calling "guestfs_getxattrs". However some Linux filesystem implementations are buggy and do not provide a way to list out attributes. For these filesystems (notably ntfs-3g) you have to know the names of the extended attributes you want in advance and call this function. Extended attribute values are blobs of binary data. If there is no extended attribute named "name", this returns an error. See also: "guestfs_getxattrs", "guestfs_lgetxattr", attr(5). This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use. (Added in 1.7.24) guestfs_getxattrs struct guestfs_xattr_list * guestfs_getxattrs (guestfs_h *g, const char *path); This call lists the extended attributes of the file or directory "path". At the system call level, this is a combination of the listxattr(2) and getxattr(2) calls. See also: "guestfs_lgetxattrs", attr(5). This function returns a "struct guestfs_xattr_list *", or NULL if there was an error. The caller must call "guestfs_free_xattr_list" after use. (Added in 1.0.59) guestfs_glob_expand char ** guestfs_glob_expand (guestfs_h *g, const char *pattern); This command searches for all the pathnames matching "pattern" according to the wildcard expansion rules used by the shell. If no paths match, then this returns an empty list (note: not an error). It is just a wrapper around the C glob(3) function with flags "GLOB_MARK|GLOB_BRACE". See that manual page for more details. Notice that there is no equivalent command for expanding a device name (eg. "/dev/sd*"). Use "guestfs_list_devices", "guestfs_list_partitions" etc functions instead. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.0.50) guestfs_grep char ** guestfs_grep (guestfs_h *g, const char *regex, const char *path); This calls the external "grep" program and returns the matching lines. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.66) guestfs_grepi char ** guestfs_grepi (guestfs_h *g, const char *regex, const char *path); This calls the external "grep -i" program and returns the matching lines. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.66) guestfs_grub_install int guestfs_grub_install (guestfs_h *g, const char *root, const char *device); This command installs GRUB 1 (the Grand Unified Bootloader) on "device", with the root directory being "root". Notes: o There is currently no way in the API to install grub2, which is used by most modern Linux guests. It is possible to run the grub2 command from the guest, although see the caveats in "RUNNING COMMANDS" in guestfs(3). o This uses "grub-install" from the host. Unfortunately grub is not always compatible with itself, so this only works in rather narrow circumstances. Careful testing with each guest version is advisable. o If grub-install reports the error "No suitable drive was found in the generated device map." it may be that you need to create a "/boot/grub/device.map" file first that contains the mapping between grub device names and Linux device names. It is usually sufficient to create a file containing: (hd0) /dev/vda replacing "/dev/vda" with the name of the installation device. This function returns 0 on success or -1 on error. (Added in 1.0.17) guestfs_head char ** guestfs_head (guestfs_h *g, const char *path); This command returns up to the first 10 lines of a file as a list of strings. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.54) guestfs_head_n char ** guestfs_head_n (guestfs_h *g, int nrlines, const char *path); If the parameter "nrlines" is a positive number, this returns the first "nrlines" lines of the file "path". If the parameter "nrlines" is a negative number, this returns lines from the file "path", excluding the last "nrlines" lines. If the parameter "nrlines" is zero, this returns an empty list. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.54) guestfs_hexdump char * guestfs_hexdump (guestfs_h *g, const char *path); This runs "hexdump -C" on the given "path". The result is the human-readable, canonical hex dump of the file. This function returns a string, or NULL on error. The caller must free the returned string after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.22) guestfs_initrd_cat char * guestfs_initrd_cat (guestfs_h *g, const char *initrdpath, const char *filename, size_t *size_r); This command unpacks the file "filename" from the initrd file called "initrdpath". The filename must be given without the initial "/" character. For example, in guestfish you could use the following command to examine the boot script (usually called "/init") contained in a Linux initrd or initramfs image: initrd-cat /boot/initrd-<version>.img init See also "guestfs_initrd_list". This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.84) guestfs_initrd_list char ** guestfs_initrd_list (guestfs_h *g, const char *path); This command lists out files contained in an initrd. The files are listed without any initial "/" character. The files are listed in the order they appear (not necessarily alphabetical). Directory names are listed as separate items. Old Linux kernels (2.4 and earlier) used a compressed ext2 filesystem as initrd. We only support the newer initramfs format (compressed cpio files). This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.0.54) guestfs_inotify_add_watch int64_t guestfs_inotify_add_watch (guestfs_h *g, const char *path, int mask); Watch "path" for the events listed in "mask". Note that if "path" is a directory then events within that directory are watched, but this does not happen recursively (in subdirectories). Note for non-C or non-Linux callers: the inotify events are defined by the Linux kernel ABI and are listed in "/usr/include/sys/inotify.h". On error this function returns -1. (Added in 1.0.66) guestfs_inotify_close int guestfs_inotify_close (guestfs_h *g); This closes the inotify handle which was previously opened by inotify_init. It removes all watches, throws away any pending events, and deallocates all resources. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_inotify_files char ** guestfs_inotify_files (guestfs_h *g); This function is a helpful wrapper around "guestfs_inotify_read" which just returns a list of pathnames of objects that were touched. The returned pathnames are sorted and deduplicated. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.0.66) guestfs_inotify_init int guestfs_inotify_init (guestfs_h *g, int maxevents); This command creates a new inotify handle. The inotify subsystem can be used to notify events which happen to objects in the guest filesystem. "maxevents" is the maximum number of events which will be queued up between calls to "guestfs_inotify_read" or "guestfs_inotify_files". If this is passed as 0, then the kernel (or previously set) default is used. For Linux 2.6.29 the default was 16384 events. Beyond this limit, the kernel throws away events, but records the fact that it threw them away by setting a flag "IN_Q_OVERFLOW" in the returned structure list (see "guestfs_inotify_read"). Before any events are generated, you have to add some watches to the internal watch list. See: "guestfs_inotify_add_watch" and "guestfs_inotify_rm_watch". Queued up events should be read periodically by calling "guestfs_inotify_read" (or "guestfs_inotify_files" which is just a helpful wrapper around "guestfs_inotify_read"). If you don't read the events out often enough then you risk the internal queue overflowing. The handle should be closed after use by calling "guestfs_inotify_close". This also removes any watches automatically. See also inotify(7) for an overview of the inotify interface as exposed by the Linux kernel, which is roughly what we expose via libguestfs. Note that there is one global inotify handle per libguestfs instance. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_inotify_read struct guestfs_inotify_event_list * guestfs_inotify_read (guestfs_h *g); Return the complete queue of events that have happened since the previous read call. If no events have happened, this returns an empty list. Note: In order to make sure that all events have been read, you must call this function repeatedly until it returns an empty list. The reason is that the call will read events up to the maximum appliance-to-host message size and leave remaining events in the queue. This function returns a "struct guestfs_inotify_event_list *", or NULL if there was an error. The caller must call "guestfs_free_inotify_event_list" after use. (Added in 1.0.66) guestfs_inotify_rm_watch int guestfs_inotify_rm_watch (guestfs_h *g, int wd); Remove a previously defined inotify watch. See "guestfs_inotify_add_watch". This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_inspect_get_arch char * guestfs_inspect_get_arch (guestfs_h *g, const char *root); This returns the architecture of the inspected operating system. The possible return values are listed under "guestfs_file_architecture". If the architecture could not be determined, then the string "unknown" is returned. Please read "INSPECTION" in guestfs(3) for more details. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.5.3) guestfs_inspect_get_distro char * guestfs_inspect_get_distro (guestfs_h *g, const char *root); This returns the distro (distribution) of the inspected operating system. Currently defined distros are: "archlinux" Arch Linux. "buildroot" Buildroot-derived distro, but not one we specifically recognize. "centos" CentOS. "cirros" Cirros. "debian" Debian. "fedora" Fedora. "freedos" FreeDOS. "gentoo" Gentoo. "linuxmint" Linux Mint. "mageia" Mageia. "mandriva" Mandriva. "meego" MeeGo. "opensuse" OpenSUSE. "pardus" Pardus. "redhat-based" Some Red Hat-derived distro. "rhel" Red Hat Enterprise Linux. "scientificlinux" Scientific Linux. "slackware" Slackware. "ttylinux" ttylinux. "ubuntu" Ubuntu. "unknown" The distro could not be determined. "windows" Windows does not have distributions. This string is returned if the OS type is Windows. Future versions of libguestfs may return other strings here. The caller should be prepared to handle any string. Please read "INSPECTION" in guestfs(3) for more details. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.5.3) guestfs_inspect_get_drive_mappings char ** guestfs_inspect_get_drive_mappings (guestfs_h *g, const char *root); This call is useful for Windows which uses a primitive system of assigning drive letters (like "C:") to partitions. This inspection API examines the Windows Registry to find out how disks/partitions are mapped to drive letters, and returns a hash table as in the example below: C => /dev/vda2 E => /dev/vdb1 F => /dev/vdc1 Note that keys are drive letters. For Windows, the key is case insensitive and just contains the drive letter, without the customary colon separator character. In future we may support other operating systems that also used drive letters, but the keys for those might not be case insensitive and might be longer than 1 character. For example in OS-9, hard drives were named "h0", "h1" etc. For Windows guests, currently only hard drive mappings are returned. Removable disks (eg. DVD-ROMs) are ignored. For guests that do not use drive mappings, or if the drive mappings could not be determined, this returns an empty hash table. Please read "INSPECTION" in guestfs(3) for more details. See also "guestfs_inspect_get_mountpoints", "guestfs_inspect_get_filesystems". This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use. (Added in 1.9.17) guestfs_inspect_get_filesystems char ** guestfs_inspect_get_filesystems (guestfs_h *g, const char *root); This returns a list of all the filesystems that we think are associated with this operating system. This includes the root filesystem, other ordinary filesystems, and non-mounted devices like swap partitions. In the case of a multi-boot virtual machine, it is possible for a filesystem to be shared between operating systems. Please read "INSPECTION" in guestfs(3) for more details. See also "guestfs_inspect_get_mountpoints". This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.5.3) guestfs_inspect_get_format char * guestfs_inspect_get_format (guestfs_h *g, const char *root); This returns the format of the inspected operating system. You can use it to detect install images, live CDs and similar. Currently defined formats are: "installed" This is an installed operating system. "installer" The disk image being inspected is not an installed operating system, but a bootable install disk, live CD, or similar. "unknown" The format of this disk image is not known. Future versions of libguestfs may return other strings here. The caller should be prepared to handle any string. Please read "INSPECTION" in guestfs(3) for more details. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.9.4) guestfs_inspect_get_hostname char * guestfs_inspect_get_hostname (guestfs_h *g, const char *root); This function returns the hostname of the operating system as found by inspection of the guest's configuration files. If the hostname could not be determined, then the string "unknown" is returned. Please read "INSPECTION" in guestfs(3) for more details. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.7.9) guestfs_inspect_get_icon char * guestfs_inspect_get_icon (guestfs_h *g, const char *root, size_t *size_r, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_INSPECT_GET_ICON_FAVICON, int favicon, GUESTFS_INSPECT_GET_ICON_HIGHQUALITY, int highquality, This function returns an icon corresponding to the inspected operating system. The icon is returned as a buffer containing a PNG image (re-encoded to PNG if necessary). If it was not possible to get an icon this function returns a zero-length (non-NULL) buffer. Callers must check for this case. Libguestfs will start by looking for a file called "/etc/favicon.png" or "C:etcfavicon.png" and if it has the correct format, the contents of this file will be returned. You can disable favicons by passing the optional "favicon" boolean as false (default is true). If finding the favicon fails, then we look in other places in the guest for a suitable icon. If the optional "highquality" boolean is true then only high quality icons are returned, which means only icons of high resolution with an alpha channel. The default (false) is to return any icon we can, even if it is of substandard quality. Notes: o Unlike most other inspection API calls, the guest's disks must be mounted up before you call this, since it needs to read information from the guest filesystem during the call. o Security: The icon data comes from the untrusted guest, and should be treated with caution. PNG files have been known to contain exploits. Ensure that libpng (or other relevant libraries) are fully up to date before trying to process or display the icon. o The PNG image returned can be any size. It might not be square. Libguestfs tries to return the largest, highest quality icon available. The application must scale the icon to the required size. o Extracting icons from Windows guests requires the external "wrestool" program from the "icoutils" package, and several programs ("bmptopnm", "pnmtopng", "pamcut") from the "netpbm" package. These must be installed separately. o Operating system icons are usually trademarks. Seek legal advice before using trademarks in applications. This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use. (Added in 1.11.12) guestfs_inspect_get_icon_va char * guestfs_inspect_get_icon_va (guestfs_h *g, const char *root, size_t *size_r, va_list args); This is the "va_list variant" of "guestfs_inspect_get_icon". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_inspect_get_icon_argv char * guestfs_inspect_get_icon_argv (guestfs_h *g, const char *root, size_t *size_r, const struct guestfs_inspect_get_icon_argv *optargs); This is the "argv variant" of "guestfs_inspect_get_icon". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_inspect_get_major_version int guestfs_inspect_get_major_version (guestfs_h *g, const char *root); This returns the major version number of the inspected operating system. Windows uses a consistent versioning scheme which is not reflected in the popular public names used by the operating system. Notably the operating system known as "Windows 7" is really version 6.1 (ie. major = 6, minor = 1). You can find out the real versions corresponding to releases of Windows by consulting Wikipedia or MSDN. If the version could not be determined, then 0 is returned. Please read "INSPECTION" in guestfs(3) for more details. On error this function returns -1. (Added in 1.5.3) guestfs_inspect_get_minor_version int guestfs_inspect_get_minor_version (guestfs_h *g, const char *root); This returns the minor version number of the inspected operating system. If the version could not be determined, then 0 is returned. Please read "INSPECTION" in guestfs(3) for more details. See also "guestfs_inspect_get_major_version". On error this function returns -1. (Added in 1.5.3) guestfs_inspect_get_mountpoints char ** guestfs_inspect_get_mountpoints (guestfs_h *g, const char *root); This returns a hash of where we think the filesystems associated with this operating system should be mounted. Callers should note that this is at best an educated guess made by reading configuration files such as "/etc/fstab". In particular note that this may return filesystems which are non-existent or not mountable and callers should be prepared to handle or ignore failures if they try to mount them. Each element in the returned hashtable has a key which is the path of the mountpoint (eg. "/boot") and a value which is the filesystem that would be mounted there (eg. "/dev/sda1"). Non-mounted devices such as swap devices are not returned in this list. For operating systems like Windows which still use drive letters, this call will only return an entry for the first drive "mounted on" "/". For information about the mapping of drive letters to partitions, see "guestfs_inspect_get_drive_mappings". Please read "INSPECTION" in guestfs(3) for more details. See also "guestfs_inspect_get_filesystems". This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use. (Added in 1.5.3) guestfs_inspect_get_package_format char * guestfs_inspect_get_package_format (guestfs_h *g, const char *root); This function and "guestfs_inspect_get_package_management" return the package format and package management tool used by the inspected operating system. For example for Fedora these functions would return "rpm" (package format) and "yum" (package management). This returns the string "unknown" if we could not determine the package format or if the operating system does not have a real packaging system (eg. Windows). Possible strings include: "rpm", "deb", "ebuild", "pisi", "pacman", "pkgsrc". Future versions of libguestfs may return other strings. Please read "INSPECTION" in guestfs(3) for more details. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.7.5) guestfs_inspect_get_package_management char * guestfs_inspect_get_package_management (guestfs_h *g, const char *root); "guestfs_inspect_get_package_format" and this function return the package format and package management tool used by the inspected operating system. For example for Fedora these functions would return "rpm" (package format) and "yum" (package management). This returns the string "unknown" if we could not determine the package management tool or if the operating system does not have a real packaging system (eg. Windows). Possible strings include: "yum", "up2date", "apt" (for all Debian derivatives), "portage", "pisi", "pacman", "urpmi", "zypper". Future versions of libguestfs may return other strings. Please read "INSPECTION" in guestfs(3) for more details. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.7.5) guestfs_inspect_get_product_name char * guestfs_inspect_get_product_name (guestfs_h *g, const char *root); This returns the product name of the inspected operating system. The product name is generally some freeform string which can be displayed to the user, but should not be parsed by programs. If the product name could not be determined, then the string "unknown" is returned. Please read "INSPECTION" in guestfs(3) for more details. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.5.3) guestfs_inspect_get_product_variant char * guestfs_inspect_get_product_variant (guestfs_h *g, const char *root); This returns the product variant of the inspected operating system. For Windows guests, this returns the contents of the Registry key "HKLMSoftwareMicrosoftWindows NTCurrentVersion" "InstallationType" which is usually a string such as "Client" or "Server" (other values are possible). This can be used to distinguish consumer and enterprise versions of Windows that have the same version number (for example, Windows 7 and Windows 2008 Server are both version 6.1, but the former is "Client" and the latter is "Server"). For enterprise Linux guests, in future we intend this to return the product variant such as "Desktop", "Server" and so on. But this is not implemented at present. If the product variant could not be determined, then the string "unknown" is returned. Please read "INSPECTION" in guestfs(3) for more details. See also "guestfs_inspect_get_product_name", "guestfs_inspect_get_major_version". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.9.13) guestfs_inspect_get_roots char ** guestfs_inspect_get_roots (guestfs_h *g); This function is a convenient way to get the list of root devices, as returned from a previous call to "guestfs_inspect_os", but without redoing the whole inspection process. This returns an empty list if either no root devices were found or the caller has not called "guestfs_inspect_os". Please read "INSPECTION" in guestfs(3) for more details. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.7.3) guestfs_inspect_get_type char * guestfs_inspect_get_type (guestfs_h *g, const char *root); This returns the type of the inspected operating system. Currently defined types are: "linux" Any Linux-based operating system. "windows" Any Microsoft Windows operating system. "freebsd" FreeBSD. "netbsd" NetBSD. "hurd" GNU/Hurd. "dos" MS-DOS, FreeDOS and others. "unknown" The operating system type could not be determined. Future versions of libguestfs may return other strings here. The caller should be prepared to handle any string. Please read "INSPECTION" in guestfs(3) for more details. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.5.3) guestfs_inspect_get_windows_current_control_set char * guestfs_inspect_get_windows_current_control_set (guestfs_h *g, const char *root); This returns the Windows CurrentControlSet of the inspected guest. The CurrentControlSet is a registry key name such as "ControlSet001". This call assumes that the guest is Windows and that the Registry could be examined by inspection. If this is not the case then an error is returned. Please read "INSPECTION" in guestfs(3) for more details. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.9.17) guestfs_inspect_get_windows_systemroot char * guestfs_inspect_get_windows_systemroot (guestfs_h *g, const char *root); This returns the Windows systemroot of the inspected guest. The systemroot is a directory path such as "/WINDOWS". This call assumes that the guest is Windows and that the systemroot could be determined by inspection. If this is not the case then an error is returned. Please read "INSPECTION" in guestfs(3) for more details. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.5.25) guestfs_inspect_is_live int guestfs_inspect_is_live (guestfs_h *g, const char *root); If "guestfs_inspect_get_format" returns "installer" (this is an install disk), then this returns true if a live image was detected on the disk. Please read "INSPECTION" in guestfs(3) for more details. This function returns a C truth value on success or -1 on error. (Added in 1.9.4) guestfs_inspect_is_multipart int guestfs_inspect_is_multipart (guestfs_h *g, const char *root); If "guestfs_inspect_get_format" returns "installer" (this is an install disk), then this returns true if the disk is part of a set. Please read "INSPECTION" in guestfs(3) for more details. This function returns a C truth value on success or -1 on error. (Added in 1.9.4) guestfs_inspect_is_netinst int guestfs_inspect_is_netinst (guestfs_h *g, const char *root); If "guestfs_inspect_get_format" returns "installer" (this is an install disk), then this returns true if the disk is a network installer, ie. not a self-contained install CD but one which is likely to require network access to complete the install. Please read "INSPECTION" in guestfs(3) for more details. This function returns a C truth value on success or -1 on error. (Added in 1.9.4) guestfs_inspect_list_applications struct guestfs_application_list * guestfs_inspect_list_applications (guestfs_h *g, const char *root); Return the list of applications installed in the operating system. Note: This call works differently from other parts of the inspection API. You have to call "guestfs_inspect_os", then "guestfs_inspect_get_mountpoints", then mount up the disks, before calling this. Listing applications is a significantly more difficult operation which requires access to the full filesystem. Also note that unlike the other "guestfs_inspect_get_*" calls which are just returning data cached in the libguestfs handle, this call actually reads parts of the mounted filesystems during the call. This returns an empty list if the inspection code was not able to determine the list of applications. The application structure contains the following fields: "app_name" The name of the application. For Red Hat-derived and Debian-derived Linux guests, this is the package name. "app_display_name" The display name of the application, sometimes localized to the install language of the guest operating system. If unavailable this is returned as an empty string "". Callers needing to display something can use "app_name" instead. "app_epoch" For package managers which use epochs, this contains the epoch of the package (an integer). If unavailable, this is returned as 0. "app_version" The version string of the application or package. If unavailable this is returned as an empty string "". "app_release" The release string of the application or package, for package managers that use this. If unavailable this is returned as an empty string "". "app_install_path" The installation path of the application (on operating systems such as Windows which use installation paths). This path is in the format used by the guest operating system, it is not a libguestfs path. If unavailable this is returned as an empty string "". "app_trans_path" The install path translated into a libguestfs path. If unavailable this is returned as an empty string "". "app_publisher" The name of the publisher of the application, for package managers that use this. If unavailable this is returned as an empty string "". "app_url" The URL (eg. upstream URL) of the application. If unavailable this is returned as an empty string "". "app_source_package" For packaging systems which support this, the name of the source package. If unavailable this is returned as an empty string "". "app_summary" A short (usually one line) description of the application or package. If unavailable this is returned as an empty string "". "app_description" A longer description of the application or package. If unavailable this is returned as an empty string "". Please read "INSPECTION" in guestfs(3) for more details. This function returns a "struct guestfs_application_list *", or NULL if there was an error. The caller must call "guestfs_free_application_list" after use. (Added in 1.7.8) guestfs_inspect_os char ** guestfs_inspect_os (guestfs_h *g); This function uses other libguestfs functions and certain heuristics to inspect the disk(s) (usually disks belonging to a virtual machine), looking for operating systems. The list returned is empty if no operating systems were found. If one operating system was found, then this returns a list with a single element, which is the name of the root filesystem of this operating system. It is also possible for this function to return a list containing more than one element, indicating a dual-boot or multi-boot virtual machine, with each element being the root filesystem of one of the operating systems. You can pass the root string(s) returned to other "guestfs_inspect_get_*" functions in order to query further information about each operating system, such as the name and version. This function uses other libguestfs features such as "guestfs_mount_ro" and "guestfs_umount_all" in order to mount and unmount filesystems and look at the contents. This should be called with no disks currently mounted. The function may also use Augeas, so any existing Augeas handle will be closed. This function cannot decrypt encrypted disks. The caller must do that first (supplying the necessary keys) if the disk is encrypted. Please read "INSPECTION" in guestfs(3) for more details. See also "guestfs_list_filesystems". This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.5.3) guestfs_is_blockdev int guestfs_is_blockdev (guestfs_h *g, const char *path); This returns "true" if and only if there is a block device with the given "path" name. See also "guestfs_stat". This function returns a C truth value on success or -1 on error. (Added in 1.5.10) guestfs_is_chardev int guestfs_is_chardev (guestfs_h *g, const char *path); This returns "true" if and only if there is a character device with the given "path" name. See also "guestfs_stat". This function returns a C truth value on success or -1 on error. (Added in 1.5.10) guestfs_is_config int guestfs_is_config (guestfs_h *g); This returns true iff this handle is being configured (in the "CONFIG" state). For more information on states, see guestfs(3). This function returns a C truth value on success or -1 on error. (Added in 1.0.2) guestfs_is_dir int guestfs_is_dir (guestfs_h *g, const char *path); This returns "true" if and only if there is a directory with the given "path" name. Note that it returns false for other objects like files. See also "guestfs_stat". This function returns a C truth value on success or -1 on error. (Added in 0.8) guestfs_is_fifo int guestfs_is_fifo (guestfs_h *g, const char *path); This returns "true" if and only if there is a FIFO (named pipe) with the given "path" name. See also "guestfs_stat". This function returns a C truth value on success or -1 on error. (Added in 1.5.10) guestfs_is_file int guestfs_is_file (guestfs_h *g, const char *path); This returns "true" if and only if there is a regular file with the given "path" name. Note that it returns false for other objects like directories. See also "guestfs_stat". This function returns a C truth value on success or -1 on error. (Added in 0.8) guestfs_is_launching int guestfs_is_launching (guestfs_h *g); This returns true iff this handle is launching the subprocess (in the "LAUNCHING" state). For more information on states, see guestfs(3). This function returns a C truth value on success or -1 on error. (Added in 1.0.2) guestfs_is_lv int guestfs_is_lv (guestfs_h *g, const char *device); This command tests whether "device" is a logical volume, and returns true iff this is the case. This function returns a C truth value on success or -1 on error. (Added in 1.5.3) guestfs_is_ready int guestfs_is_ready (guestfs_h *g); This returns true iff this handle is ready to accept commands (in the "READY" state). For more information on states, see guestfs(3). This function returns a C truth value on success or -1 on error. (Added in 1.0.2) guestfs_is_socket int guestfs_is_socket (guestfs_h *g, const char *path); This returns "true" if and only if there is a Unix domain socket with the given "path" name. See also "guestfs_stat". This function returns a C truth value on success or -1 on error. (Added in 1.5.10) guestfs_is_symlink int guestfs_is_symlink (guestfs_h *g, const char *path); This returns "true" if and only if there is a symbolic link with the given "path" name. See also "guestfs_stat". This function returns a C truth value on success or -1 on error. (Added in 1.5.10) guestfs_is_zero int guestfs_is_zero (guestfs_h *g, const char *path); This returns true iff the file exists and the file is empty or it contains all zero bytes. This function returns a C truth value on success or -1 on error. (Added in 1.11.8) guestfs_is_zero_device int guestfs_is_zero_device (guestfs_h *g, const char *device); This returns true iff the device exists and contains all zero bytes. Note that for large devices this can take a long time to run. This function returns a C truth value on success or -1 on error. (Added in 1.11.8) guestfs_isoinfo struct guestfs_isoinfo * guestfs_isoinfo (guestfs_h *g, const char *isofile); This is the same as "guestfs_isoinfo_device" except that it works for an ISO file located inside some other mounted filesystem. Note that in the common case where you have added an ISO file as a libguestfs device, you would not call this. Instead you would call "guestfs_isoinfo_device". This function returns a "struct guestfs_isoinfo *", or NULL if there was an error. The caller must call "guestfs_free_isoinfo" after use. (Added in 1.17.19) guestfs_isoinfo_device struct guestfs_isoinfo * guestfs_isoinfo_device (guestfs_h *g, const char *device); "device" is an ISO device. This returns a struct of information read from the primary volume descriptor (the ISO equivalent of the superblock) of the device. Usually it is more efficient to use the isoinfo(1) command with the -d option on the host to analyze ISO files, instead of going through libguestfs. For information on the primary volume descriptor fields, see <http://wiki.osdev.org/ISO_9660#The_Primary_Volume_Descriptor> This function returns a "struct guestfs_isoinfo *", or NULL if there was an error. The caller must call "guestfs_free_isoinfo" after use. (Added in 1.17.19) guestfs_kill_subprocess int guestfs_kill_subprocess (guestfs_h *g); This kills the qemu subprocess. You should never need to call this. This function returns 0 on success or -1 on error. (Added in 0.3) guestfs_launch int guestfs_launch (guestfs_h *g); Internally libguestfs is implemented by running a virtual machine using qemu(1). You should call this after configuring the handle (eg. adding drives) but before performing any actions. This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 0.3) guestfs_lchown int guestfs_lchown (guestfs_h *g, int owner, int group, const char *path); Change the file owner to "owner" and group to "group". This is like "guestfs_chown" but if "path" is a symlink then the link itself is changed, not the target. Only numeric uid and gid are supported. If you want to use names, you will need to locate and parse the password file yourself (Augeas support makes this relatively easy). This function returns 0 on success or -1 on error. (Added in 1.0.77) guestfs_lgetxattr char * guestfs_lgetxattr (guestfs_h *g, const char *path, const char *name, size_t *size_r); Get a single extended attribute from file "path" named "name". If "path" is a symlink, then this call returns an extended attribute from the symlink. Normally it is better to get all extended attributes from a file in one go by calling "guestfs_getxattrs". However some Linux filesystem implementations are buggy and do not provide a way to list out attributes. For these filesystems (notably ntfs-3g) you have to know the names of the extended attributes you want in advance and call this function. Extended attribute values are blobs of binary data. If there is no extended attribute named "name", this returns an error. See also: "guestfs_lgetxattrs", "guestfs_getxattr", attr(5). This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use. (Added in 1.7.24) guestfs_lgetxattrs struct guestfs_xattr_list * guestfs_lgetxattrs (guestfs_h *g, const char *path); This is the same as "guestfs_getxattrs", but if "path" is a symbolic link, then it returns the extended attributes of the link itself. This function returns a "struct guestfs_xattr_list *", or NULL if there was an error. The caller must call "guestfs_free_xattr_list" after use. (Added in 1.0.59) guestfs_list_9p char ** guestfs_list_9p (guestfs_h *g); List all 9p filesystems attached to the guest. A list of mount tags is returned. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.11.12) guestfs_list_devices char ** guestfs_list_devices (guestfs_h *g); List all the block devices. The full block device names are returned, eg. "/dev/sda". See also "guestfs_list_filesystems". This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 0.4) guestfs_list_dm_devices char ** guestfs_list_dm_devices (guestfs_h *g); List all device mapper devices. The returned list contains "/dev/mapper/*" devices, eg. ones created by a previous call to "guestfs_luks_open". Device mapper devices which correspond to logical volumes are not returned in this list. Call "guestfs_lvs" if you want to list logical volumes. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.11.15) guestfs_list_filesystems char ** guestfs_list_filesystems (guestfs_h *g); This inspection command looks for filesystems on partitions, block devices and logical volumes, returning a list of devices containing filesystems and their type. The return value is a hash, where the keys are the devices containing filesystems, and the values are the filesystem types. For example: "/dev/sda1" => "ntfs" "/dev/sda2" => "ext2" "/dev/vg_guest/lv_root" => "ext4" "/dev/vg_guest/lv_swap" => "swap" The value can have the special value "unknown", meaning the content of the device is undetermined or empty. "swap" means a Linux swap partition. This command runs other libguestfs commands, which might include "guestfs_mount" and "guestfs_umount", and therefore you should use this soon after launch and only when nothing is mounted. Not all of the filesystems returned will be mountable. In particular, swap partitions are returned in the list. Also this command does not check that each filesystem found is valid and mountable, and some filesystems might be mountable but require special options. Filesystems may not all belong to a single logical operating system (use "guestfs_inspect_os" to look for OSes). This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use. (Added in 1.5.15) guestfs_list_md_devices char ** guestfs_list_md_devices (guestfs_h *g); List all Linux md devices. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.15.4) guestfs_list_partitions char ** guestfs_list_partitions (guestfs_h *g); List all the partitions detected on all block devices. The full partition device names are returned, eg. "/dev/sda1" This does not return logical volumes. For that you will need to call "guestfs_lvs". See also "guestfs_list_filesystems". This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 0.4) guestfs_ll char * guestfs_ll (guestfs_h *g, const char *directory); List the files in "directory" (relative to the root directory, there is no cwd) in the format of 'ls -la'. This command is mostly useful for interactive sessions. It is not intended that you try to parse the output string. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 0.4) guestfs_llz char * guestfs_llz (guestfs_h *g, const char *directory); List the files in "directory" in the format of 'ls -laZ'. This command is mostly useful for interactive sessions. It is not intended that you try to parse the output string. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.17.6) guestfs_ln int guestfs_ln (guestfs_h *g, const char *target, const char *linkname); This command creates a hard link using the "ln" command. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_ln_f int guestfs_ln_f (guestfs_h *g, const char *target, const char *linkname); This command creates a hard link using the "ln -f" command. The -f option removes the link ("linkname") if it exists already. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_ln_s int guestfs_ln_s (guestfs_h *g, const char *target, const char *linkname); This command creates a symbolic link using the "ln -s" command. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_ln_sf int guestfs_ln_sf (guestfs_h *g, const char *target, const char *linkname); This command creates a symbolic link using the "ln -sf" command, The -f option removes the link ("linkname") if it exists already. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_lremovexattr int guestfs_lremovexattr (guestfs_h *g, const char *xattr, const char *path); This is the same as "guestfs_removexattr", but if "path" is a symbolic link, then it removes an extended attribute of the link itself. This function returns 0 on success or -1 on error. (Added in 1.0.59) guestfs_ls char ** guestfs_ls (guestfs_h *g, const char *directory); List the files in "directory" (relative to the root directory, there is no cwd). The '.' and '..' entries are not returned, but hidden files are shown. This command is mostly useful for interactive sessions. Programs should probably use "guestfs_readdir" instead. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 0.4) guestfs_lsetxattr int guestfs_lsetxattr (guestfs_h *g, const char *xattr, const char *val, int vallen, const char *path); This is the same as "guestfs_setxattr", but if "path" is a symbolic link, then it sets an extended attribute of the link itself. This function returns 0 on success or -1 on error. (Added in 1.0.59) guestfs_lstat struct guestfs_stat * guestfs_lstat (guestfs_h *g, const char *path); Returns file information for the given "path". This is the same as "guestfs_stat" except that if "path" is a symbolic link, then the link is stat-ed, not the file it refers to. This is the same as the lstat(2) system call. This function returns a "struct guestfs_stat *", or NULL if there was an error. The caller must call "guestfs_free_stat" after use. (Added in 0.9.2) guestfs_lstatlist struct guestfs_stat_list * guestfs_lstatlist (guestfs_h *g, const char *path, char *const *names); This call allows you to perform the "guestfs_lstat" operation on multiple files, where all files are in the directory "path". "names" is the list of files from this directory. On return you get a list of stat structs, with a one-to-one correspondence to the "names" list. If any name did not exist or could not be lstat'd, then the "ino" field of that structure is set to "-1". This call is intended for programs that want to efficiently list a directory contents without making many round-trips. See also "guestfs_lxattrlist" for a similarly efficient call for getting extended attributes. Very long directory listings might cause the protocol message size to be exceeded, causing this call to fail. The caller must split up such requests into smaller groups of names. This function returns a "struct guestfs_stat_list *", or NULL if there was an error. The caller must call "guestfs_free_stat_list" after use. (Added in 1.0.77) guestfs_luks_add_key int guestfs_luks_add_key (guestfs_h *g, const char *device, const char *key, const char *newkey, int keyslot); This command adds a new key on LUKS device "device". "key" is any existing key, and is used to access the device. "newkey" is the new key to add. "keyslot" is the key slot that will be replaced. Note that if "keyslot" already contains a key, then this command will fail. You have to use "guestfs_luks_kill_slot" first to remove that key. This function returns 0 on success or -1 on error. This function takes a key or passphrase parameter which could contain sensitive material. Read the section "KEYS AND PASSPHRASES" for more information. (Added in 1.5.2) guestfs_luks_close int guestfs_luks_close (guestfs_h *g, const char *device); This closes a LUKS device that was created earlier by "guestfs_luks_open" or "guestfs_luks_open_ro". The "device" parameter must be the name of the LUKS mapping device (ie. "/dev/mapper/mapname") and not the name of the underlying block device. This function returns 0 on success or -1 on error. (Added in 1.5.1) guestfs_luks_format int guestfs_luks_format (guestfs_h *g, const char *device, const char *key, int keyslot); This command erases existing data on "device" and formats the device as a LUKS encrypted device. "key" is the initial key, which is added to key slot "slot". (LUKS supports 8 key slots, numbered 0-7). This function returns 0 on success or -1 on error. This function takes a key or passphrase parameter which could contain sensitive material. Read the section "KEYS AND PASSPHRASES" for more information. (Added in 1.5.2) guestfs_luks_format_cipher int guestfs_luks_format_cipher (guestfs_h *g, const char *device, const char *key, int keyslot, const char *cipher); This command is the same as "guestfs_luks_format" but it also allows you to set the "cipher" used. This function returns 0 on success or -1 on error. This function takes a key or passphrase parameter which could contain sensitive material. Read the section "KEYS AND PASSPHRASES" for more information. (Added in 1.5.2) guestfs_luks_kill_slot int guestfs_luks_kill_slot (guestfs_h *g, const char *device, const char *key, int keyslot); This command deletes the key in key slot "keyslot" from the encrypted LUKS device "device". "key" must be one of the other keys. This function returns 0 on success or -1 on error. This function takes a key or passphrase parameter which could contain sensitive material. Read the section "KEYS AND PASSPHRASES" for more information. (Added in 1.5.2) guestfs_luks_open int guestfs_luks_open (guestfs_h *g, const char *device, const char *key, const char *mapname); This command opens a block device which has been encrypted according to the Linux Unified Key Setup (LUKS) standard. "device" is the encrypted block device or partition. The caller must supply one of the keys associated with the LUKS block device, in the "key" parameter. This creates a new block device called "/dev/mapper/mapname". Reads and writes to this block device are decrypted from and encrypted to the underlying "device" respectively. If this block device contains LVM volume groups, then calling "guestfs_vgscan" followed by "guestfs_vg_activate_all" will make them visible. Use "guestfs_list_dm_devices" to list all device mapper devices. This function returns 0 on success or -1 on error. This function takes a key or passphrase parameter which could contain sensitive material. Read the section "KEYS AND PASSPHRASES" for more information. (Added in 1.5.1) guestfs_luks_open_ro int guestfs_luks_open_ro (guestfs_h *g, const char *device, const char *key, const char *mapname); This is the same as "guestfs_luks_open" except that a read-only mapping is created. This function returns 0 on success or -1 on error. This function takes a key or passphrase parameter which could contain sensitive material. Read the section "KEYS AND PASSPHRASES" for more information. (Added in 1.5.1) guestfs_lvcreate int guestfs_lvcreate (guestfs_h *g, const char *logvol, const char *volgroup, int mbytes); This creates an LVM logical volume called "logvol" on the volume group "volgroup", with "size" megabytes. This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_lvcreate_free int guestfs_lvcreate_free (guestfs_h *g, const char *logvol, const char *volgroup, int percent); Create an LVM logical volume called "/dev/volgroup/logvol", using approximately "percent" % of the free space remaining in the volume group. Most usefully, when "percent" is 100 this will create the largest possible LV. This function returns 0 on success or -1 on error. (Added in 1.17.18) guestfs_lvm_canonical_lv_name char * guestfs_lvm_canonical_lv_name (guestfs_h *g, const char *lvname); This converts alternative naming schemes for LVs that you might find to the canonical name. For example, "/dev/mapper/VG-LV" is converted to "/dev/VG/LV". This command returns an error if the "lvname" parameter does not refer to a logical volume. See also "guestfs_is_lv". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.5.24) guestfs_lvm_clear_filter int guestfs_lvm_clear_filter (guestfs_h *g); This undoes the effect of "guestfs_lvm_set_filter". LVM will be able to see every block device. This command also clears the LVM cache and performs a volume group scan. This function returns 0 on success or -1 on error. (Added in 1.5.1) guestfs_lvm_remove_all int guestfs_lvm_remove_all (guestfs_h *g); This command removes all LVM logical volumes, volume groups and physical volumes. This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_lvm_set_filter int guestfs_lvm_set_filter (guestfs_h *g, char *const *devices); This sets the LVM device filter so that LVM will only be able to "see" the block devices in the list "devices", and will ignore all other attached block devices. Where disk image(s) contain duplicate PVs or VGs, this command is useful to get LVM to ignore the duplicates, otherwise LVM can get confused. Note also there are two types of duplication possible: either cloned PVs/VGs which have identical UUIDs; or VGs that are not cloned but just happen to have the same name. In normal operation you cannot create this situation, but you can do it outside LVM, eg. by cloning disk images or by bit twiddling inside the LVM metadata. This command also clears the LVM cache and performs a volume group scan. You can filter whole block devices or individual partitions. You cannot use this if any VG is currently in use (eg. contains a mounted filesystem), even if you are not filtering out that VG. This function returns 0 on success or -1 on error. (Added in 1.5.1) guestfs_lvremove int guestfs_lvremove (guestfs_h *g, const char *device); Remove an LVM logical volume "device", where "device" is the path to the LV, such as "/dev/VG/LV". You can also remove all LVs in a volume group by specifying the VG name, "/dev/VG". This function returns 0 on success or -1 on error. (Added in 1.0.13) guestfs_lvrename int guestfs_lvrename (guestfs_h *g, const char *logvol, const char *newlogvol); Rename a logical volume "logvol" with the new name "newlogvol". This function returns 0 on success or -1 on error. (Added in 1.0.83) guestfs_lvresize int guestfs_lvresize (guestfs_h *g, const char *device, int mbytes); This resizes (expands or shrinks) an existing LVM logical volume to "mbytes". When reducing, data in the reduced part is lost. This function returns 0 on success or -1 on error. (Added in 1.0.27) guestfs_lvresize_free int guestfs_lvresize_free (guestfs_h *g, const char *lv, int percent); This expands an existing logical volume "lv" so that it fills "pc"% of the remaining free space in the volume group. Commonly you would call this with pc = 100 which expands the logical volume as much as possible, using all remaining free space in the volume group. This function returns 0 on success or -1 on error. (Added in 1.3.3) guestfs_lvs char ** guestfs_lvs (guestfs_h *g); List all the logical volumes detected. This is the equivalent of the lvs(8) command. This returns a list of the logical volume device names (eg. "/dev/VolGroup00/LogVol00"). See also "guestfs_lvs_full", "guestfs_list_filesystems". This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 0.4) guestfs_lvs_full struct guestfs_lvm_lv_list * guestfs_lvs_full (guestfs_h *g); List all the logical volumes detected. This is the equivalent of the lvs(8) command. The "full" version includes all fields. This function returns a "struct guestfs_lvm_lv_list *", or NULL if there was an error. The caller must call "guestfs_free_lvm_lv_list" after use. (Added in 0.4) guestfs_lvuuid char * guestfs_lvuuid (guestfs_h *g, const char *device); This command returns the UUID of the LVM LV "device". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.87) guestfs_lxattrlist struct guestfs_xattr_list * guestfs_lxattrlist (guestfs_h *g, const char *path, char *const *names); This call allows you to get the extended attributes of multiple files, where all files are in the directory "path". "names" is the list of files from this directory. On return you get a flat list of xattr structs which must be interpreted sequentially. The first xattr struct always has a zero-length "attrname". "attrval" in this struct is zero-length to indicate there was an error doing "lgetxattr" for this file, or is a C string which is a decimal number (the number of following attributes for this file, which could be "0"). Then after the first xattr struct are the zero or more attributes for the first named file. This repeats for the second and subsequent files. This call is intended for programs that want to efficiently list a directory contents without making many round-trips. See also "guestfs_lstatlist" for a similarly efficient call for getting standard stats. Very long directory listings might cause the protocol message size to be exceeded, causing this call to fail. The caller must split up such requests into smaller groups of names. This function returns a "struct guestfs_xattr_list *", or NULL if there was an error. The caller must call "guestfs_free_xattr_list" after use. (Added in 1.0.77) guestfs_md_create int guestfs_md_create (guestfs_h *g, const char *name, char *const *devices, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_MD_CREATE_MISSINGBITMAP, int64_t missingbitmap, GUESTFS_MD_CREATE_NRDEVICES, int nrdevices, GUESTFS_MD_CREATE_SPARE, int spare, GUESTFS_MD_CREATE_CHUNK, int64_t chunk, GUESTFS_MD_CREATE_LEVEL, const char *level, Create a Linux md (RAID) device named "name" on the devices in the list "devices". The optional parameters are: "missingbitmap" A bitmap of missing devices. If a bit is set it means that a missing device is added to the array. The least significant bit corresponds to the first device in the array. As examples: If "devices = ["/dev/sda"]" and "missingbitmap = 0x1" then the resulting array would be "[<missing>, "/dev/sda"]". If "devices = ["/dev/sda"]" and "missingbitmap = 0x2" then the resulting array would be "["/dev/sda", <missing>]". This defaults to 0 (no missing devices). The length of "devices" + the number of bits set in "missingbitmap" must equal "nrdevices" + "spare". "nrdevices" The number of active RAID devices. If not set, this defaults to the length of "devices" plus the number of bits set in "missingbitmap". "spare" The number of spare devices. If not set, this defaults to 0. "chunk" The chunk size in bytes. "level" The RAID level, which can be one of: linear, raid0, 0, stripe, raid1, 1, mirror, raid4, 4, raid5, 5, raid6, 6, raid10, 10. Some of these are synonymous, and more levels may be added in future. If not set, this defaults to "raid1". This function returns 0 on success or -1 on error. (Added in 1.15.6) guestfs_md_create_va int guestfs_md_create_va (guestfs_h *g, const char *name, char *const *devices, va_list args); This is the "va_list variant" of "guestfs_md_create". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_md_create_argv int guestfs_md_create_argv (guestfs_h *g, const char *name, char *const *devices, const struct guestfs_md_create_argv *optargs); This is the "argv variant" of "guestfs_md_create". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_md_detail char ** guestfs_md_detail (guestfs_h *g, const char *md); This command exposes the output of 'mdadm -DY <md>'. The following fields are usually present in the returned hash. Other fields may also be present. "level" The raid level of the MD device. "devices" The number of underlying devices in the MD device. "metadata" The metadata version used. "uuid" The UUID of the MD device. "name" The name of the MD device. This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use. (Added in 1.15.6) guestfs_md_stat struct guestfs_mdstat_list * guestfs_md_stat (guestfs_h *g, const char *md); This call returns a list of the underlying devices which make up the single software RAID array device "md". To get a list of software RAID devices, call "guestfs_list_md_devices". Each structure returned corresponds to one device along with additional status information: "mdstat_device" The name of the underlying device. "mdstat_index" The index of this device within the array. "mdstat_flags" Flags associated with this device. This is a string containing (in no specific order) zero or more of the following flags: "W" write-mostly "F" device is faulty "S" device is a RAID spare "R" replacement This function returns a "struct guestfs_mdstat_list *", or NULL if there was an error. The caller must call "guestfs_free_mdstat_list" after use. (Added in 1.17.21) guestfs_md_stop int guestfs_md_stop (guestfs_h *g, const char *md); This command deactivates the MD array named "md". The device is stopped, but it is not destroyed or zeroed. This function returns 0 on success or -1 on error. (Added in 1.15.6) guestfs_mkdir int guestfs_mkdir (guestfs_h *g, const char *path); Create a directory named "path". This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_mkdir_mode int guestfs_mkdir_mode (guestfs_h *g, const char *path, int mode); This command creates a directory, setting the initial permissions of the directory to "mode". For common Linux filesystems, the actual mode which is set will be "mode & ~umask & 01777". Non-native-Linux filesystems may interpret the mode in other ways. See also "guestfs_mkdir", "guestfs_umask" This function returns 0 on success or -1 on error. (Added in 1.0.77) guestfs_mkdir_p int guestfs_mkdir_p (guestfs_h *g, const char *path); Create a directory named "path", creating any parent directories as necessary. This is like the "mkdir -p" shell command. This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_mkdtemp char * guestfs_mkdtemp (guestfs_h *g, const char *tmpl); This command creates a temporary directory. The "tmpl" parameter should be a full pathname for the temporary directory name with the final six characters being "XXXXXX". For example: "/tmp/myprogXXXXXX" or "/Temp/myprogXXXXXX", the second one being suitable for Windows filesystems. The name of the temporary directory that was created is returned. The temporary directory is created with mode 0700 and is owned by root. The caller is responsible for deleting the temporary directory and its contents after use. See also: mkdtemp(3) This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.54) guestfs_mke2fs_J int guestfs_mke2fs_J (guestfs_h *g, const char *fstype, int blocksize, const char *device, const char *journal); This creates an ext2/3/4 filesystem on "device" with an external journal on "journal". It is equivalent to the command: mke2fs -t fstype -b blocksize -J device=<journal> <device> See also "guestfs_mke2journal". This function returns 0 on success or -1 on error. (Added in 1.0.68) guestfs_mke2fs_JL int guestfs_mke2fs_JL (guestfs_h *g, const char *fstype, int blocksize, const char *device, const char *label); This creates an ext2/3/4 filesystem on "device" with an external journal on the journal labeled "label". See also "guestfs_mke2journal_L". This function returns 0 on success or -1 on error. (Added in 1.0.68) guestfs_mke2fs_JU int guestfs_mke2fs_JU (guestfs_h *g, const char *fstype, int blocksize, const char *device, const char *uuid); This creates an ext2/3/4 filesystem on "device" with an external journal on the journal with UUID "uuid". See also "guestfs_mke2journal_U". This function returns 0 on success or -1 on error. (Added in 1.0.68) guestfs_mke2journal int guestfs_mke2journal (guestfs_h *g, int blocksize, const char *device); This creates an ext2 external journal on "device". It is equivalent to the command: mke2fs -O journal_dev -b blocksize device This function returns 0 on success or -1 on error. (Added in 1.0.68) guestfs_mke2journal_L int guestfs_mke2journal_L (guestfs_h *g, int blocksize, const char *label, const char *device); This creates an ext2 external journal on "device" with label "label". This function returns 0 on success or -1 on error. (Added in 1.0.68) guestfs_mke2journal_U int guestfs_mke2journal_U (guestfs_h *g, int blocksize, const char *uuid, const char *device); This creates an ext2 external journal on "device" with UUID "uuid". This function returns 0 on success or -1 on error. (Added in 1.0.68) guestfs_mkfifo int guestfs_mkfifo (guestfs_h *g, int mode, const char *path); This call creates a FIFO (named pipe) called "path" with mode "mode". It is just a convenient wrapper around "guestfs_mknod". The mode actually set is affected by the umask. This function returns 0 on success or -1 on error. (Added in 1.0.55) guestfs_mkfs int guestfs_mkfs (guestfs_h *g, const char *fstype, const char *device); This creates a filesystem on "device" (usually a partition or LVM logical volume). The filesystem type is "fstype", for example "ext3". This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_mkfs_b int guestfs_mkfs_b (guestfs_h *g, const char *fstype, int blocksize, const char *device); This function is deprecated. In new code, use the "guestfs_mkfs_opts" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This call is similar to "guestfs_mkfs", but it allows you to control the block size of the resulting filesystem. Supported block sizes depend on the filesystem type, but typically they are 1024, 2048 or 4096 only. For VFAT and NTFS the "blocksize" parameter is treated as the requested cluster size. This function returns 0 on success or -1 on error. (Added in 1.0.68) guestfs_mkfs_btrfs int guestfs_mkfs_btrfs (guestfs_h *g, char *const *devices, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_MKFS_BTRFS_ALLOCSTART, int64_t allocstart, GUESTFS_MKFS_BTRFS_BYTECOUNT, int64_t bytecount, GUESTFS_MKFS_BTRFS_DATATYPE, const char *datatype, GUESTFS_MKFS_BTRFS_LEAFSIZE, int leafsize, GUESTFS_MKFS_BTRFS_LABEL, const char *label, GUESTFS_MKFS_BTRFS_METADATA, const char *metadata, GUESTFS_MKFS_BTRFS_NODESIZE, int nodesize, GUESTFS_MKFS_BTRFS_SECTORSIZE, int sectorsize, Create a btrfs filesystem, allowing all configurables to be set. For more information on the optional arguments, see mkfs.btrfs(8). Since btrfs filesystems can span multiple devices, this takes a non-empty list of devices. To create general filesystems, use "guestfs_mkfs_opts". This function returns 0 on success or -1 on error. (Added in 1.17.25) guestfs_mkfs_btrfs_va int guestfs_mkfs_btrfs_va (guestfs_h *g, char *const *devices, va_list args); This is the "va_list variant" of "guestfs_mkfs_btrfs". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_mkfs_btrfs_argv int guestfs_mkfs_btrfs_argv (guestfs_h *g, char *const *devices, const struct guestfs_mkfs_btrfs_argv *optargs); This is the "argv variant" of "guestfs_mkfs_btrfs". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_mkfs_opts int guestfs_mkfs_opts (guestfs_h *g, const char *fstype, const char *device, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_MKFS_OPTS_BLOCKSIZE, int blocksize, GUESTFS_MKFS_OPTS_FEATURES, const char *features, GUESTFS_MKFS_OPTS_INODE, int inode, GUESTFS_MKFS_OPTS_SECTORSIZE, int sectorsize, This function creates a filesystem on "device". The filesystem type is "fstype", for example "ext3". The optional arguments are: "blocksize" The filesystem block size. Supported block sizes depend on the filesystem type, but typically they are 1024, 2048 or 4096 for Linux ext2/3 filesystems. For VFAT and NTFS the "blocksize" parameter is treated as the requested cluster size. For UFS block sizes, please see mkfs.ufs(8). "features" This passes the -O parameter to the external mkfs program. For certain filesystem types, this allows extra filesystem features to be selected. See mke2fs(8) and mkfs.ufs(8) for more details. You cannot use this optional parameter with the "gfs" or "gfs2" filesystem type. "inode" This passes the -I parameter to the external mke2fs(8) program which sets the inode size (only for ext2/3/4 filesystems at present). "sectorsize" This passes the -S parameter to external mkfs.ufs(8) program, which sets sector size for ufs filesystem. This function returns 0 on success or -1 on error. (Added in 1.7.19) guestfs_mkfs_opts_va int guestfs_mkfs_opts_va (guestfs_h *g, const char *fstype, const char *device, va_list args); This is the "va_list variant" of "guestfs_mkfs_opts". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_mkfs_opts_argv int guestfs_mkfs_opts_argv (guestfs_h *g, const char *fstype, const char *device, const struct guestfs_mkfs_opts_argv *optargs); This is the "argv variant" of "guestfs_mkfs_opts". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_mkmountpoint int guestfs_mkmountpoint (guestfs_h *g, const char *exemptpath); "guestfs_mkmountpoint" and "guestfs_rmmountpoint" are specialized calls that can be used to create extra mountpoints before mounting the first filesystem. These calls are only necessary in some very limited circumstances, mainly the case where you want to mount a mix of unrelated and/or read- only filesystems together. For example, live CDs often contain a "Russian doll" nest of filesystems, an ISO outer layer, with a squashfs image inside, with an ext2/3 image inside that. You can unpack this as follows in guestfish: add-ro Fedora-11-i686-Live.iso run mkmountpoint /cd mkmountpoint /sqsh mkmountpoint /ext3fs mount /dev/sda /cd mount-loop /cd/LiveOS/squashfs.img /sqsh mount-loop /sqsh/LiveOS/ext3fs.img /ext3fs The inner filesystem is now unpacked under the /ext3fs mountpoint. "guestfs_mkmountpoint" is not compatible with "guestfs_umount_all". You may get unexpected errors if you try to mix these calls. It is safest to manually unmount filesystems and remove mountpoints after use. "guestfs_umount_all" unmounts filesystems by sorting the paths longest first, so for this to work for manual mountpoints, you must ensure that the innermost mountpoints have the longest pathnames, as in the example code above. For more details see <https://bugzilla.redhat.com/show_bug.cgi?id=599503> Autosync [see "guestfs_set_autosync", this is set by default on handles] can cause "guestfs_umount_all" to be called when the handle is closed which can also trigger these issues. This function returns 0 on success or -1 on error. (Added in 1.0.62) guestfs_mknod int guestfs_mknod (guestfs_h *g, int mode, int devmajor, int devminor, const char *path); This call creates block or character special devices, or named pipes (FIFOs). The "mode" parameter should be the mode, using the standard constants. "devmajor" and "devminor" are the device major and minor numbers, only used when creating block and character special devices. Note that, just like mknod(2), the mode must be bitwise OR'd with S_IFBLK, S_IFCHR, S_IFIFO or S_IFSOCK (otherwise this call just creates a regular file). These constants are available in the standard Linux header files, or you can use "guestfs_mknod_b", "guestfs_mknod_c" or "guestfs_mkfifo" which are wrappers around this command which bitwise OR in the appropriate constant for you. The mode actually set is affected by the umask. This function returns 0 on success or -1 on error. (Added in 1.0.55) guestfs_mknod_b int guestfs_mknod_b (guestfs_h *g, int mode, int devmajor, int devminor, const char *path); This call creates a block device node called "path" with mode "mode" and device major/minor "devmajor" and "devminor". It is just a convenient wrapper around "guestfs_mknod". The mode actually set is affected by the umask. This function returns 0 on success or -1 on error. (Added in 1.0.55) guestfs_mknod_c int guestfs_mknod_c (guestfs_h *g, int mode, int devmajor, int devminor, const char *path); This call creates a char device node called "path" with mode "mode" and device major/minor "devmajor" and "devminor". It is just a convenient wrapper around "guestfs_mknod". The mode actually set is affected by the umask. This function returns 0 on success or -1 on error. (Added in 1.0.55) guestfs_mkswap int guestfs_mkswap (guestfs_h *g, const char *device); Create a swap partition on "device". This function returns 0 on success or -1 on error. (Added in 1.0.55) guestfs_mkswap_L int guestfs_mkswap_L (guestfs_h *g, const char *label, const char *device); Create a swap partition on "device" with label "label". Note that you cannot attach a swap label to a block device (eg. "/dev/sda"), just to a partition. This appears to be a limitation of the kernel or swap tools. This function returns 0 on success or -1 on error. (Added in 1.0.55) guestfs_mkswap_U int guestfs_mkswap_U (guestfs_h *g, const char *uuid, const char *device); Create a swap partition on "device" with UUID "uuid". This function returns 0 on success or -1 on error. (Added in 1.0.55) guestfs_mkswap_file int guestfs_mkswap_file (guestfs_h *g, const char *path); Create a swap file. This command just writes a swap file signature to an existing file. To create the file itself, use something like "guestfs_fallocate". This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_modprobe int guestfs_modprobe (guestfs_h *g, const char *modulename); This loads a kernel module in the appliance. The kernel module must have been whitelisted when libguestfs was built (see "appliance/kmod.whitelist.in" in the source). This function returns 0 on success or -1 on error. (Added in 1.0.68) guestfs_mount int guestfs_mount (guestfs_h *g, const char *device, const char *mountpoint); Mount a guest disk at a position in the filesystem. Block devices are named "/dev/sda", "/dev/sdb" and so on, as they were added to the guest. If those block devices contain partitions, they will have the usual names (eg. "/dev/sda1"). Also LVM "/dev/VG/LV"-style names can be used. The rules are the same as for mount(2): A filesystem must first be mounted on "/" before others can be mounted. Other filesystems can only be mounted on directories which already exist. The mounted filesystem is writable, if we have sufficient permissions on the underlying device. Before libguestfs 1.13.16, this call implicitly added the options "sync" and "noatime". The "sync" option greatly slowed writes and caused many problems for users. If your program might need to work with older versions of libguestfs, use "guestfs_mount_options" instead (using an empty string for the first parameter if you don't want any options). This function returns 0 on success or -1 on error. (Added in 0.3) guestfs_mount_9p int guestfs_mount_9p (guestfs_h *g, const char *mounttag, const char *mountpoint, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_MOUNT_9P_OPTIONS, const char *options, Mount the virtio-9p filesystem with the tag "mounttag" on the directory "mountpoint". If required, "trans=virtio" will be automatically added to the options. Any other options required can be passed in the optional "options" parameter. This function returns 0 on success or -1 on error. (Added in 1.11.12) guestfs_mount_9p_va int guestfs_mount_9p_va (guestfs_h *g, const char *mounttag, const char *mountpoint, va_list args); This is the "va_list variant" of "guestfs_mount_9p". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_mount_9p_argv int guestfs_mount_9p_argv (guestfs_h *g, const char *mounttag, const char *mountpoint, const struct guestfs_mount_9p_argv *optargs); This is the "argv variant" of "guestfs_mount_9p". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_mount_local int guestfs_mount_local (guestfs_h *g, const char *localmountpoint, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_MOUNT_LOCAL_READONLY, int readonly, GUESTFS_MOUNT_LOCAL_OPTIONS, const char *options, GUESTFS_MOUNT_LOCAL_CACHETIMEOUT, int cachetimeout, GUESTFS_MOUNT_LOCAL_DEBUGCALLS, int debugcalls, This call exports the libguestfs-accessible filesystem to a local mountpoint (directory) called "localmountpoint". Ordinary reads and writes to files and directories under "localmountpoint" are redirected through libguestfs. If the optional "readonly" flag is set to true, then writes to the filesystem return error "EROFS". "options" is a comma-separated list of mount options. See guestmount(1) for some useful options. "cachetimeout" sets the timeout (in seconds) for cached directory entries. The default is 60 seconds. See guestmount(1) for further information. If "debugcalls" is set to true, then additional debugging information is generated for every FUSE call. When "guestfs_mount_local" returns, the filesystem is ready, but is not processing requests (access to it will block). You have to call "guestfs_mount_local_run" to run the main loop. See "MOUNT LOCAL" in guestfs(3) for full documentation. This function returns 0 on success or -1 on error. (Added in 1.17.22) guestfs_mount_local_va int guestfs_mount_local_va (guestfs_h *g, const char *localmountpoint, va_list args); This is the "va_list variant" of "guestfs_mount_local". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_mount_local_argv int guestfs_mount_local_argv (guestfs_h *g, const char *localmountpoint, const struct guestfs_mount_local_argv *optargs); This is the "argv variant" of "guestfs_mount_local". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_mount_local_run int guestfs_mount_local_run (guestfs_h *g); Run the main loop which translates kernel calls to libguestfs calls. This should only be called after "guestfs_mount_local" returns successfully. The call will not return until the filesystem is unmounted. Note you must not make concurrent libguestfs calls on the same handle from another thread, with the exception of "guestfs_umount_local". You may call this from a different thread than the one which called "guestfs_mount_local", subject to the usual rules for threads and libguestfs (see "MULTIPLE HANDLES AND MULTIPLE THREADS" in guestfs(3)). See "MOUNT LOCAL" in guestfs(3) for full documentation. This function returns 0 on success or -1 on error. (Added in 1.17.22) guestfs_mount_loop int guestfs_mount_loop (guestfs_h *g, const char *file, const char *mountpoint); This command lets you mount "file" (a filesystem image in a file) on a mount point. It is entirely equivalent to the command "mount -o loop file mountpoint". This function returns 0 on success or -1 on error. (Added in 1.0.54) guestfs_mount_options int guestfs_mount_options (guestfs_h *g, const char *options, const char *device, const char *mountpoint); This is the same as the "guestfs_mount" command, but it allows you to set the mount options as for the mount(8) -o flag. If the "options" parameter is an empty string, then no options are passed (all options default to whatever the filesystem uses). This function returns 0 on success or -1 on error. (Added in 1.0.10) guestfs_mount_ro int guestfs_mount_ro (guestfs_h *g, const char *device, const char *mountpoint); This is the same as the "guestfs_mount" command, but it mounts the filesystem with the read-only (-o ro) flag. This function returns 0 on success or -1 on error. (Added in 1.0.10) guestfs_mount_vfs int guestfs_mount_vfs (guestfs_h *g, const char *options, const char *vfstype, const char *device, const char *mountpoint); This is the same as the "guestfs_mount" command, but it allows you to set both the mount options and the vfstype as for the mount(8) -o and -t flags. This function returns 0 on success or -1 on error. (Added in 1.0.10) guestfs_mountpoints char ** guestfs_mountpoints (guestfs_h *g); This call is similar to "guestfs_mounts". That call returns a list of devices. This one returns a hash table (map) of device name to directory where the device is mounted. This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use. (Added in 1.0.62) guestfs_mounts char ** guestfs_mounts (guestfs_h *g); This returns the list of currently mounted filesystems. It returns the list of devices (eg. "/dev/sda1", "/dev/VG/LV"). Some internal mounts are not shown. See also: "guestfs_mountpoints" This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 0.8) guestfs_mv int guestfs_mv (guestfs_h *g, const char *src, const char *dest); This moves a file from "src" to "dest" where "dest" is either a destination filename or destination directory. This function returns 0 on success or -1 on error. (Added in 1.0.18) guestfs_ntfs_3g_probe int guestfs_ntfs_3g_probe (guestfs_h *g, int rw, const char *device); This command runs the ntfs-3g.probe(8) command which probes an NTFS "device" for mountability. (Not all NTFS volumes can be mounted read- write, and some cannot be mounted at all). "rw" is a boolean flag. Set it to true if you want to test if the volume can be mounted read-write. Set it to false if you want to test if the volume can be mounted read-only. The return value is an integer which 0 if the operation would succeed, or some non-zero value documented in the ntfs-3g.probe(8) manual page. On error this function returns -1. (Added in 1.0.43) guestfs_ntfsclone_in int guestfs_ntfsclone_in (guestfs_h *g, const char *backupfile, const char *device); Restore the "backupfile" (from a previous call to "guestfs_ntfsclone_out") to "device", overwriting any existing contents of this device. This function returns 0 on success or -1 on error. (Added in 1.17.9) guestfs_ntfsclone_out int guestfs_ntfsclone_out (guestfs_h *g, const char *device, const char *backupfile, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_NTFSCLONE_OUT_METADATAONLY, int metadataonly, GUESTFS_NTFSCLONE_OUT_RESCUE, int rescue, GUESTFS_NTFSCLONE_OUT_IGNOREFSCHECK, int ignorefscheck, GUESTFS_NTFSCLONE_OUT_PRESERVETIMESTAMPS, int preservetimestamps, GUESTFS_NTFSCLONE_OUT_FORCE, int force, Stream the NTFS filesystem "device" to the local file "backupfile". The format used for the backup file is a special format used by the ntfsclone(8) tool. If the optional "metadataonly" flag is true, then only the metadata is saved, losing all the user data (this is useful for diagnosing some filesystem problems). The optional "rescue", "ignorefscheck", "preservetimestamps" and "force" flags have precise meanings detailed in the ntfsclone(8) man page. Use "guestfs_ntfsclone_in" to restore the file back to a libguestfs device. This function returns 0 on success or -1 on error. (Added in 1.17.9) guestfs_ntfsclone_out_va int guestfs_ntfsclone_out_va (guestfs_h *g, const char *device, const char *backupfile, va_list args); This is the "va_list variant" of "guestfs_ntfsclone_out". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_ntfsclone_out_argv int guestfs_ntfsclone_out_argv (guestfs_h *g, const char *device, const char *backupfile, const struct guestfs_ntfsclone_out_argv *optargs); This is the "argv variant" of "guestfs_ntfsclone_out". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_ntfsfix int guestfs_ntfsfix (guestfs_h *g, const char *device, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_NTFSFIX_CLEARBADSECTORS, int clearbadsectors, This command repairs some fundamental NTFS inconsistencies, resets the NTFS journal file, and schedules an NTFS consistency check for the first boot into Windows. This is not an equivalent of Windows "chkdsk". It does not scan the filesystem for inconsistencies. The optional "clearbadsectors" flag clears the list of bad sectors. This is useful after cloning a disk with bad sectors to a new disk. This function returns 0 on success or -1 on error. (Added in 1.17.9) guestfs_ntfsfix_va int guestfs_ntfsfix_va (guestfs_h *g, const char *device, va_list args); This is the "va_list variant" of "guestfs_ntfsfix". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_ntfsfix_argv int guestfs_ntfsfix_argv (guestfs_h *g, const char *device, const struct guestfs_ntfsfix_argv *optargs); This is the "argv variant" of "guestfs_ntfsfix". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_ntfsresize int guestfs_ntfsresize (guestfs_h *g, const char *device); This function is deprecated. In new code, use the "guestfs_ntfsresize_opts" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This command resizes an NTFS filesystem, expanding or shrinking it to the size of the underlying device. Note: After the resize operation, the filesystem is marked as requiring a consistency check (for safety). You have to boot into Windows to perform this check and clear this condition. Furthermore, ntfsresize refuses to resize filesystems which have been marked in this way. So in effect it is not possible to call ntfsresize multiple times on a single filesystem without booting into Windows between each resize. See also ntfsresize(8). This function returns 0 on success or -1 on error. (Added in 1.3.2) guestfs_ntfsresize_opts int guestfs_ntfsresize_opts (guestfs_h *g, const char *device, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_NTFSRESIZE_OPTS_SIZE, int64_t size, GUESTFS_NTFSRESIZE_OPTS_FORCE, int force, This command resizes an NTFS filesystem, expanding or shrinking it to the size of the underlying device. The optional parameters are: "size" The new size (in bytes) of the filesystem. If omitted, the filesystem is resized to fit the container (eg. partition). "force" If this option is true, then force the resize of the filesystem even if the filesystem is marked as requiring a consistency check. After the resize operation, the filesystem is always marked as requiring a consistency check (for safety). You have to boot into Windows to perform this check and clear this condition. If you don't set the "force" option then it is not possible to call "guestfs_ntfsresize_opts" multiple times on a single filesystem without booting into Windows between each resize. See also ntfsresize(8). This function returns 0 on success or -1 on error. (Added in 1.11.15) guestfs_ntfsresize_opts_va int guestfs_ntfsresize_opts_va (guestfs_h *g, const char *device, va_list args); This is the "va_list variant" of "guestfs_ntfsresize_opts". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_ntfsresize_opts_argv int guestfs_ntfsresize_opts_argv (guestfs_h *g, const char *device, const struct guestfs_ntfsresize_opts_argv *optargs); This is the "argv variant" of "guestfs_ntfsresize_opts". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_ntfsresize_size int guestfs_ntfsresize_size (guestfs_h *g, const char *device, int64_t size); This function is deprecated. In new code, use the "guestfs_ntfsresize_opts" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This command is the same as "guestfs_ntfsresize" except that it allows you to specify the new size (in bytes) explicitly. This function returns 0 on success or -1 on error. (Added in 1.3.14) guestfs_part_add int guestfs_part_add (guestfs_h *g, const char *device, const char *prlogex, int64_t startsect, int64_t endsect); This command adds a partition to "device". If there is no partition table on the device, call "guestfs_part_init" first. The "prlogex" parameter is the type of partition. Normally you should pass "p" or "primary" here, but MBR partition tables also support "l" (or "logical") and "e" (or "extended") partition types. "startsect" and "endsect" are the start and end of the partition in sectors. "endsect" may be negative, which means it counts backwards from the end of the disk ("-1" is the last sector). Creating a partition which covers the whole disk is not so easy. Use "guestfs_part_disk" to do that. This function returns 0 on success or -1 on error. (Added in 1.0.78) guestfs_part_del int guestfs_part_del (guestfs_h *g, const char *device, int partnum); This command deletes the partition numbered "partnum" on "device". Note that in the case of MBR partitioning, deleting an extended partition also deletes any logical partitions it contains. This function returns 0 on success or -1 on error. (Added in 1.3.2) guestfs_part_disk int guestfs_part_disk (guestfs_h *g, const char *device, const char *parttype); This command is simply a combination of "guestfs_part_init" followed by "guestfs_part_add" to create a single primary partition covering the whole disk. "parttype" is the partition table type, usually "mbr" or "gpt", but other possible values are described in "guestfs_part_init". This function returns 0 on success or -1 on error. (Added in 1.0.78) guestfs_part_get_bootable int guestfs_part_get_bootable (guestfs_h *g, const char *device, int partnum); This command returns true if the partition "partnum" on "device" has the bootable flag set. See also "guestfs_part_set_bootable". This function returns a C truth value on success or -1 on error. (Added in 1.3.2) guestfs_part_get_mbr_id int guestfs_part_get_mbr_id (guestfs_h *g, const char *device, int partnum); Returns the MBR type byte (also known as the ID byte) from the numbered partition "partnum". Note that only MBR (old DOS-style) partitions have type bytes. You will get undefined results for other partition table types (see "guestfs_part_get_parttype"). On error this function returns -1. (Added in 1.3.2) guestfs_part_get_parttype char * guestfs_part_get_parttype (guestfs_h *g, const char *device); This command examines the partition table on "device" and returns the partition table type (format) being used. Common return values include: "msdos" (a DOS/Windows style MBR partition table), "gpt" (a GPT/EFI-style partition table). Other values are possible, although unusual. See "guestfs_part_init" for a full list. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.78) guestfs_part_init int guestfs_part_init (guestfs_h *g, const char *device, const char *parttype); This creates an empty partition table on "device" of one of the partition types listed below. Usually "parttype" should be either "msdos" or "gpt" (for large disks). Initially there are no partitions. Following this, you should call "guestfs_part_add" for each partition required. Possible values for "parttype" are: efi gpt Intel EFI / GPT partition table. This is recommended for >= 2 TB partitions that will be accessed from Linux and Intel-based Mac OS X. It also has limited backwards compatibility with the "mbr" format. mbr msdos The standard PC "Master Boot Record" (MBR) format used by MS-DOS and Windows. This partition type will only work for device sizes up to 2 TB. For large disks we recommend using "gpt". Other partition table types that may work but are not supported include: aix AIX disk labels. amiga rdb Amiga "Rigid Disk Block" format. bsd BSD disk labels. dasd DASD, used on IBM mainframes. dvh MIPS/SGI volumes. mac Old Mac partition format. Modern Macs use "gpt". pc98 NEC PC-98 format, common in Japan apparently. sun Sun disk labels. This function returns 0 on success or -1 on error. (Added in 1.0.78) guestfs_part_list struct guestfs_partition_list * guestfs_part_list (guestfs_h *g, const char *device); This command parses the partition table on "device" and returns the list of partitions found. The fields in the returned structure are: part_num Partition number, counting from 1. part_start Start of the partition in bytes. To get sectors you have to divide by the device's sector size, see "guestfs_blockdev_getss". part_end End of the partition in bytes. part_size Size of the partition in bytes. This function returns a "struct guestfs_partition_list *", or NULL if there was an error. The caller must call "guestfs_free_partition_list" after use. (Added in 1.0.78) guestfs_part_set_bootable int guestfs_part_set_bootable (guestfs_h *g, const char *device, int partnum, int bootable); This sets the bootable flag on partition numbered "partnum" on device "device". Note that partitions are numbered from 1. The bootable flag is used by some operating systems (notably Windows) to determine which partition to boot from. It is by no means universally recognized. This function returns 0 on success or -1 on error. (Added in 1.0.78) guestfs_part_set_mbr_id int guestfs_part_set_mbr_id (guestfs_h *g, const char *device, int partnum, int idbyte); Sets the MBR type byte (also known as the ID byte) of the numbered partition "partnum" to "idbyte". Note that the type bytes quoted in most documentation are in fact hexadecimal numbers, but usually documented without any leading "0x" which might be confusing. Note that only MBR (old DOS-style) partitions have type bytes. You will get undefined results for other partition table types (see "guestfs_part_get_parttype"). This function returns 0 on success or -1 on error. (Added in 1.3.2) guestfs_part_set_name int guestfs_part_set_name (guestfs_h *g, const char *device, int partnum, const char *name); This sets the partition name on partition numbered "partnum" on device "device". Note that partitions are numbered from 1. The partition name can only be set on certain types of partition table. This works on "gpt" but not on "mbr" partitions. This function returns 0 on success or -1 on error. (Added in 1.0.78) guestfs_part_to_dev char * guestfs_part_to_dev (guestfs_h *g, const char *partition); This function takes a partition name (eg. "/dev/sdb1") and removes the partition number, returning the device name (eg. "/dev/sdb"). The named partition must exist, for example as a string returned from "guestfs_list_partitions". See also "guestfs_part_to_partnum". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.5.15) guestfs_part_to_partnum int guestfs_part_to_partnum (guestfs_h *g, const char *partition); This function takes a partition name (eg. "/dev/sdb1") and returns the partition number (eg. 1). The named partition must exist, for example as a string returned from "guestfs_list_partitions". See also "guestfs_part_to_dev". On error this function returns -1. (Added in 1.13.25) guestfs_ping_daemon int guestfs_ping_daemon (guestfs_h *g); This is a test probe into the guestfs daemon running inside the qemu subprocess. Calling this function checks that the daemon responds to the ping message, without affecting the daemon or attached block device(s) in any other way. This function returns 0 on success or -1 on error. (Added in 1.0.18) guestfs_pread char * guestfs_pread (guestfs_h *g, const char *path, int count, int64_t offset, size_t *size_r); This command lets you read part of a file. It reads "count" bytes of the file, starting at "offset", from file "path". This may read fewer bytes than requested. For further details see the pread(2) system call. See also "guestfs_pwrite", "guestfs_pread_device". This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.77) guestfs_pread_device char * guestfs_pread_device (guestfs_h *g, const char *device, int count, int64_t offset, size_t *size_r); This command lets you read part of a file. It reads "count" bytes of "device", starting at "offset". This may read fewer bytes than requested. For further details see the pread(2) system call. See also "guestfs_pread". This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.5.21) guestfs_pvcreate int guestfs_pvcreate (guestfs_h *g, const char *device); This creates an LVM physical volume on the named "device", where "device" should usually be a partition name such as "/dev/sda1". This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_pvremove int guestfs_pvremove (guestfs_h *g, const char *device); This wipes a physical volume "device" so that LVM will no longer recognise it. The implementation uses the "pvremove" command which refuses to wipe physical volumes that contain any volume groups, so you have to remove those first. This function returns 0 on success or -1 on error. (Added in 1.0.13) guestfs_pvresize int guestfs_pvresize (guestfs_h *g, const char *device); This resizes (expands or shrinks) an existing LVM physical volume to match the new size of the underlying device. This function returns 0 on success or -1 on error. (Added in 1.0.26) guestfs_pvresize_size int guestfs_pvresize_size (guestfs_h *g, const char *device, int64_t size); This command is the same as "guestfs_pvresize" except that it allows you to specify the new size (in bytes) explicitly. This function returns 0 on success or -1 on error. (Added in 1.3.14) guestfs_pvs char ** guestfs_pvs (guestfs_h *g); List all the physical volumes detected. This is the equivalent of the pvs(8) command. This returns a list of just the device names that contain PVs (eg. "/dev/sda2"). See also "guestfs_pvs_full". This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 0.4) guestfs_pvs_full struct guestfs_lvm_pv_list * guestfs_pvs_full (guestfs_h *g); List all the physical volumes detected. This is the equivalent of the pvs(8) command. The "full" version includes all fields. This function returns a "struct guestfs_lvm_pv_list *", or NULL if there was an error. The caller must call "guestfs_free_lvm_pv_list" after use. (Added in 0.4) guestfs_pvuuid char * guestfs_pvuuid (guestfs_h *g, const char *device); This command returns the UUID of the LVM PV "device". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.87) guestfs_pwrite int guestfs_pwrite (guestfs_h *g, const char *path, const char *content, size_t content_size, int64_t offset); This command writes to part of a file. It writes the data buffer "content" to the file "path" starting at offset "offset". This command implements the pwrite(2) system call, and like that system call it may not write the full data requested. The return value is the number of bytes that were actually written to the file. This could even be 0, although short writes are unlikely for regular files in ordinary circumstances. See also "guestfs_pread", "guestfs_pwrite_device". On error this function returns -1. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.3.14) guestfs_pwrite_device int guestfs_pwrite_device (guestfs_h *g, const char *device, const char *content, size_t content_size, int64_t offset); This command writes to part of a device. It writes the data buffer "content" to "device" starting at offset "offset". This command implements the pwrite(2) system call, and like that system call it may not write the full data requested (although short writes to disk devices and partitions are probably impossible with standard Linux kernels). See also "guestfs_pwrite". On error this function returns -1. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.5.20) guestfs_read_file char * guestfs_read_file (guestfs_h *g, const char *path, size_t *size_r); This calls returns the contents of the file "path" as a buffer. Unlike "guestfs_cat", this function can correctly handle files that contain embedded ASCII NUL characters. However unlike "guestfs_download", this function is limited in the total size of file that can be handled. This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.63) guestfs_read_lines char ** guestfs_read_lines (guestfs_h *g, const char *path); Return the contents of the file named "path". The file contents are returned as a list of lines. Trailing "LF" and "CRLF" character sequences are not returned. Note that this function cannot correctly handle binary files (specifically, files containing "" character which is treated as end of line). For those you need to use the "guestfs_read_file" function which has a more complex interface. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 0.7) guestfs_readdir struct guestfs_dirent_list * guestfs_readdir (guestfs_h *g, const char *dir); This returns the list of directory entries in directory "dir". All entries in the directory are returned, including "." and "..". The entries are not sorted, but returned in the same order as the underlying filesystem. Also this call returns basic file type information about each file. The "ftyp" field will contain one of the following characters: 'b' Block special 'c' Char special 'd' Directory 'f' FIFO (named pipe) 'l' Symbolic link 'r' Regular file 's' Socket 'u' Unknown file type '?' The readdir(3) call returned a "d_type" field with an unexpected value This function is primarily intended for use by programs. To get a simple list of names, use "guestfs_ls". To get a printable directory for human consumption, use "guestfs_ll". This function returns a "struct guestfs_dirent_list *", or NULL if there was an error. The caller must call "guestfs_free_dirent_list" after use. (Added in 1.0.55) guestfs_readlink char * guestfs_readlink (guestfs_h *g, const char *path); This command reads the target of a symbolic link. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.66) guestfs_readlinklist char ** guestfs_readlinklist (guestfs_h *g, const char *path, char *const *names); This call allows you to do a "readlink" operation on multiple files, where all files are in the directory "path". "names" is the list of files from this directory. On return you get a list of strings, with a one-to-one correspondence to the "names" list. Each string is the value of the symbolic link. If the readlink(2) operation fails on any name, then the corresponding result string is the empty string "". However the whole operation is completed even if there were readlink(2) errors, and so you can call this function with names where you don't know if they are symbolic links already (albeit slightly less efficient). This call is intended for programs that want to efficiently list a directory contents without making many round-trips. Very long directory listings might cause the protocol message size to be exceeded, causing this call to fail. The caller must split up such requests into smaller groups of names. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.0.77) guestfs_realpath char * guestfs_realpath (guestfs_h *g, const char *path); Return the canonicalized absolute pathname of "path". The returned path has no ".", ".." or symbolic link path elements. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.66) guestfs_removexattr int guestfs_removexattr (guestfs_h *g, const char *xattr, const char *path); This call removes the extended attribute named "xattr" of the file "path". See also: "guestfs_lremovexattr", attr(5). This function returns 0 on success or -1 on error. (Added in 1.0.59) guestfs_resize2fs int guestfs_resize2fs (guestfs_h *g, const char *device); This resizes an ext2, ext3 or ext4 filesystem to match the size of the underlying device. See also "RESIZE2FS ERRORS" in guestfs(3). This function returns 0 on success or -1 on error. (Added in 1.0.27) guestfs_resize2fs_M int guestfs_resize2fs_M (guestfs_h *g, const char *device); This command is the same as "guestfs_resize2fs", but the filesystem is resized to its minimum size. This works like the -M option to the "resize2fs" command. To get the resulting size of the filesystem you should call "guestfs_tune2fs_l" and read the "Block size" and "Block count" values. These two numbers, multiplied together, give the resulting size of the minimal filesystem in bytes. See also "RESIZE2FS ERRORS" in guestfs(3). This function returns 0 on success or -1 on error. (Added in 1.9.4) guestfs_resize2fs_size int guestfs_resize2fs_size (guestfs_h *g, const char *device, int64_t size); This command is the same as "guestfs_resize2fs" except that it allows you to specify the new size (in bytes) explicitly. See also "RESIZE2FS ERRORS" in guestfs(3). This function returns 0 on success or -1 on error. (Added in 1.3.14) guestfs_rm int guestfs_rm (guestfs_h *g, const char *path); Remove the single file "path". This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_rm_rf int guestfs_rm_rf (guestfs_h *g, const char *path); Remove the file or directory "path", recursively removing the contents if its a directory. This is like the "rm -rf" shell command. This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_rmdir int guestfs_rmdir (guestfs_h *g, const char *path); Remove the single directory "path". This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_rmmountpoint int guestfs_rmmountpoint (guestfs_h *g, const char *exemptpath); This calls removes a mountpoint that was previously created with "guestfs_mkmountpoint". See "guestfs_mkmountpoint" for full details. This function returns 0 on success or -1 on error. (Added in 1.0.62) guestfs_scrub_device int guestfs_scrub_device (guestfs_h *g, const char *device); This command writes patterns over "device" to make data retrieval more difficult. It is an interface to the scrub(1) program. See that manual page for more details. This function returns 0 on success or -1 on error. (Added in 1.0.52) guestfs_scrub_file int guestfs_scrub_file (guestfs_h *g, const char *file); This command writes patterns over a file to make data retrieval more difficult. The file is removed after scrubbing. It is an interface to the scrub(1) program. See that manual page for more details. This function returns 0 on success or -1 on error. (Added in 1.0.52) guestfs_scrub_freespace int guestfs_scrub_freespace (guestfs_h *g, const char *dir); This command creates the directory "dir" and then fills it with files until the filesystem is full, and scrubs the files as for "guestfs_scrub_file", and deletes them. The intention is to scrub any free space on the partition containing "dir". It is an interface to the scrub(1) program. See that manual page for more details. This function returns 0 on success or -1 on error. (Added in 1.0.52) guestfs_set_append int guestfs_set_append (guestfs_h *g, const char *append); This function is used to add additional options to the guest kernel command line. The default is "NULL" unless overridden by setting "LIBGUESTFS_APPEND" environment variable. Setting "append" to "NULL" means no additional options are passed (libguestfs always adds a few of its own). This function returns 0 on success or -1 on error. (Added in 1.0.26) guestfs_set_attach_method int guestfs_set_attach_method (guestfs_h *g, const char *attachmethod); Set the method that libguestfs uses to connect to the back end guestfsd daemon. Possible methods are: "appliance" Launch an appliance and connect to it. This is the ordinary method and the default. "unix:path" Connect to the Unix domain socket path. This method lets you connect to an existing daemon or (using virtio-serial) to a live guest. For more information, see "ATTACHING TO RUNNING DAEMONS" in guestfs(3). This function returns 0 on success or -1 on error. (Added in 1.9.8) guestfs_set_autosync int guestfs_set_autosync (guestfs_h *g, int autosync); If "autosync" is true, this enables autosync. Libguestfs will make a best effort attempt to make filesystems consistent and synchronized when the handle is closed (also if the program exits without closing handles). This is enabled by default (since libguestfs 1.5.24, previously it was disabled by default). This function returns 0 on success or -1 on error. (Added in 0.3) guestfs_set_direct int guestfs_set_direct (guestfs_h *g, int direct); If the direct appliance mode flag is enabled, then stdin and stdout are passed directly through to the appliance once it is launched. One consequence of this is that log messages aren't caught by the library and handled by "guestfs_set_log_message_callback", but go straight to stdout. You probably don't want to use this unless you know what you are doing. The default is disabled. This function returns 0 on success or -1 on error. (Added in 1.0.72) guestfs_set_e2attrs int guestfs_set_e2attrs (guestfs_h *g, const char *file, const char *attrs, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_SET_E2ATTRS_CLEAR, int clear, This sets or clears the file attributes "attrs" associated with the inode "file". "attrs" is a string of characters representing file attributes. See "guestfs_get_e2attrs" for a list of possible attributes. Not all attributes can be changed. If optional boolean "clear" is not present or false, then the "attrs" listed are set in the inode. If "clear" is true, then the "attrs" listed are cleared in the inode. In both cases, other attributes not present in the "attrs" string are left unchanged. These attributes are only present when the file is located on an ext2/3/4 filesystem. Using this call on other filesystem types will result in an error. This function returns 0 on success or -1 on error. (Added in 1.17.31) guestfs_set_e2attrs_va int guestfs_set_e2attrs_va (guestfs_h *g, const char *file, const char *attrs, va_list args); This is the "va_list variant" of "guestfs_set_e2attrs". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_set_e2attrs_argv int guestfs_set_e2attrs_argv (guestfs_h *g, const char *file, const char *attrs, const struct guestfs_set_e2attrs_argv *optargs); This is the "argv variant" of "guestfs_set_e2attrs". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_set_e2generation int guestfs_set_e2generation (guestfs_h *g, const char *file, int64_t generation); This sets the ext2 file generation of a file. See "guestfs_get_e2generation". This function returns 0 on success or -1 on error. (Added in 1.17.31) guestfs_set_e2label int guestfs_set_e2label (guestfs_h *g, const char *device, const char *label); This function is deprecated. In new code, use the "guestfs_set_label" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This sets the ext2/3/4 filesystem label of the filesystem on "device" to "label". Filesystem labels are limited to 16 characters. You can use either "guestfs_tune2fs_l" or "guestfs_get_e2label" to return the existing label on a filesystem. This function returns 0 on success or -1 on error. (Added in 1.0.15) guestfs_set_e2uuid int guestfs_set_e2uuid (guestfs_h *g, const char *device, const char *uuid); This sets the ext2/3/4 filesystem UUID of the filesystem on "device" to "uuid". The format of the UUID and alternatives such as "clear", "random" and "time" are described in the tune2fs(8) manpage. You can use either "guestfs_tune2fs_l" or "guestfs_get_e2uuid" to return the existing UUID of a filesystem. This function returns 0 on success or -1 on error. (Added in 1.0.15) guestfs_set_label int guestfs_set_label (guestfs_h *g, const char *device, const char *label); Set the filesystem label on "device" to "label". Only some filesystem types support labels, and libguestfs supports setting labels on only a subset of these. On ext2/3/4 filesystems, labels are limited to 16 bytes. On NTFS filesystems, labels are limited to 128 unicode characters. To read the label on a filesystem, call "guestfs_vfs_label". This function returns 0 on success or -1 on error. (Added in 1.17.9) guestfs_set_memsize int guestfs_set_memsize (guestfs_h *g, int memsize); This sets the memory size in megabytes allocated to the qemu subprocess. This only has any effect if called before "guestfs_launch". You can also change this by setting the environment variable "LIBGUESTFS_MEMSIZE" before the handle is created. For more information on the architecture of libguestfs, see guestfs(3). This function returns 0 on success or -1 on error. (Added in 1.0.55) guestfs_set_network int guestfs_set_network (guestfs_h *g, int network); If "network" is true, then the network is enabled in the libguestfs appliance. The default is false. This affects whether commands are able to access the network (see "RUNNING COMMANDS" in guestfs(3)). You must call this before calling "guestfs_launch", otherwise it has no effect. This function returns 0 on success or -1 on error. (Added in 1.5.4) guestfs_set_path int guestfs_set_path (guestfs_h *g, const char *searchpath); Set the path that libguestfs searches for kernel and initrd.img. The default is "$libdir/guestfs" unless overridden by setting "LIBGUESTFS_PATH" environment variable. Setting "path" to "NULL" restores the default path. This function returns 0 on success or -1 on error. (Added in 0.3) guestfs_set_pgroup int guestfs_set_pgroup (guestfs_h *g, int pgroup); If "pgroup" is true, child processes are placed into their own process group. The practical upshot of this is that signals like "SIGINT" (from users pressing "^C") won't be received by the child process. The default for this flag is false, because usually you want "^C" to kill the subprocess. Guestfish sets this flag to true when used interactively, so that "^C" can cancel long-running commands gracefully (see "guestfs_user_cancel"). This function returns 0 on success or -1 on error. (Added in 1.11.18) guestfs_set_qemu int guestfs_set_qemu (guestfs_h *g, const char *qemu); Set the qemu binary that we will use. The default is chosen when the library was compiled by the configure script. You can also override this by setting the "LIBGUESTFS_QEMU" environment variable. Setting "qemu" to "NULL" restores the default qemu binary. Note that you should call this function as early as possible after creating the handle. This is because some pre-launch operations depend on testing qemu features (by running "qemu -help"). If the qemu binary changes, we don't retest features, and so you might see inconsistent results. Using the environment variable "LIBGUESTFS_QEMU" is safest of all since that picks the qemu binary at the same time as the handle is created. This function returns 0 on success or -1 on error. (Added in 1.0.6) guestfs_set_recovery_proc int guestfs_set_recovery_proc (guestfs_h *g, int recoveryproc); If this is called with the parameter "false" then "guestfs_launch" does not create a recovery process. The purpose of the recovery process is to stop runaway qemu processes in the case where the main program aborts abruptly. This only has any effect if called before "guestfs_launch", and the default is true. About the only time when you would want to disable this is if the main process will fork itself into the background ("daemonize" itself). In this case the recovery process thinks that the main program has disappeared and so kills qemu, which is not very helpful. This function returns 0 on success or -1 on error. (Added in 1.0.77) guestfs_set_selinux int guestfs_set_selinux (guestfs_h *g, int selinux); This sets the selinux flag that is passed to the appliance at boot time. The default is "selinux=0" (disabled). Note that if SELinux is enabled, it is always in Permissive mode ("enforcing=0"). For more information on the architecture of libguestfs, see guestfs(3). This function returns 0 on success or -1 on error. (Added in 1.0.67) guestfs_set_smp int guestfs_set_smp (guestfs_h *g, int smp); Change the number of virtual CPUs assigned to the appliance. The default is 1. Increasing this may improve performance, though often it has no effect. This function must be called before "guestfs_launch". This function returns 0 on success or -1 on error. (Added in 1.13.15) guestfs_set_trace int guestfs_set_trace (guestfs_h *g, int trace); If the command trace flag is set to 1, then libguestfs calls, parameters and return values are traced. If you want to trace C API calls into libguestfs (and other libraries) then possibly a better way is to use the external ltrace(1) command. Command traces are disabled unless the environment variable "LIBGUESTFS_TRACE" is defined and set to 1. Trace messages are normally sent to "stderr", unless you register a callback to send them somewhere else (see "guestfs_set_event_callback"). This function returns 0 on success or -1 on error. (Added in 1.0.69) guestfs_set_verbose int guestfs_set_verbose (guestfs_h *g, int verbose); If "verbose" is true, this turns on verbose messages. Verbose messages are disabled unless the environment variable "LIBGUESTFS_DEBUG" is defined and set to 1. Verbose messages are normally sent to "stderr", unless you register a callback to send them somewhere else (see "guestfs_set_event_callback"). This function returns 0 on success or -1 on error. (Added in 0.3) guestfs_setcon int guestfs_setcon (guestfs_h *g, const char *context); This sets the SELinux security context of the daemon to the string "context". See the documentation about SELINUX in guestfs(3). This function returns 0 on success or -1 on error. (Added in 1.0.67) guestfs_setxattr int guestfs_setxattr (guestfs_h *g, const char *xattr, const char *val, int vallen, const char *path); This call sets the extended attribute named "xattr" of the file "path" to the value "val" (of length "vallen"). The value is arbitrary 8 bit data. See also: "guestfs_lsetxattr", attr(5). This function returns 0 on success or -1 on error. (Added in 1.0.59) guestfs_sfdisk int guestfs_sfdisk (guestfs_h *g, const char *device, int cyls, int heads, int sectors, char *const *lines); This function is deprecated. In new code, use the "guestfs_part_add" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This is a direct interface to the sfdisk(8) program for creating partitions on block devices. "device" should be a block device, for example "/dev/sda". "cyls", "heads" and "sectors" are the number of cylinders, heads and sectors on the device, which are passed directly to sfdisk as the -C, -H and -S parameters. If you pass 0 for any of these, then the corresponding parameter is omitted. Usually for 'large' disks, you can just pass 0 for these, but for small (floppy-sized) disks, sfdisk (or rather, the kernel) cannot work out the right geometry and you will need to tell it. "lines" is a list of lines that we feed to "sfdisk". For more information refer to the sfdisk(8) manpage. To create a single partition occupying the whole disk, you would pass "lines" as a single element list, when the single element being the string "," (comma). See also: "guestfs_sfdisk_l", "guestfs_sfdisk_N", "guestfs_part_init" This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_sfdiskM int guestfs_sfdiskM (guestfs_h *g, const char *device, char *const *lines); This function is deprecated. In new code, use the "guestfs_part_add" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This is a simplified interface to the "guestfs_sfdisk" command, where partition sizes are specified in megabytes only (rounded to the nearest cylinder) and you don't need to specify the cyls, heads and sectors parameters which were rarely if ever used anyway. See also: "guestfs_sfdisk", the sfdisk(8) manpage and "guestfs_part_disk" This function returns 0 on success or -1 on error. (Added in 1.0.55) guestfs_sfdisk_N int guestfs_sfdisk_N (guestfs_h *g, const char *device, int partnum, int cyls, int heads, int sectors, const char *line); This function is deprecated. In new code, use the "guestfs_part_add" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This runs sfdisk(8) option to modify just the single partition "n" (note: "n" counts from 1). For other parameters, see "guestfs_sfdisk". You should usually pass 0 for the cyls/heads/sectors parameters. See also: "guestfs_part_add" This function returns 0 on success or -1 on error. (Added in 1.0.26) guestfs_sfdisk_disk_geometry char * guestfs_sfdisk_disk_geometry (guestfs_h *g, const char *device); This displays the disk geometry of "device" read from the partition table. Especially in the case where the underlying block device has been resized, this can be different from the kernel's idea of the geometry (see "guestfs_sfdisk_kernel_geometry"). The result is in human-readable format, and not designed to be parsed. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.26) guestfs_sfdisk_kernel_geometry char * guestfs_sfdisk_kernel_geometry (guestfs_h *g, const char *device); This displays the kernel's idea of the geometry of "device". The result is in human-readable format, and not designed to be parsed. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.26) guestfs_sfdisk_l char * guestfs_sfdisk_l (guestfs_h *g, const char *device); This function is deprecated. In new code, use the "guestfs_part_list" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This displays the partition table on "device", in the human-readable output of the sfdisk(8) command. It is not intended to be parsed. See also: "guestfs_part_list" This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.26) guestfs_sh char * guestfs_sh (guestfs_h *g, const char *command); This call runs a command from the guest filesystem via the guest's "/bin/sh". This is like "guestfs_command", but passes the command to: /bin/sh -c "command" Depending on the guest's shell, this usually results in wildcards being expanded, shell expressions being interpolated and so on. All the provisos about "guestfs_command" apply to this call. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.50) guestfs_sh_lines char ** guestfs_sh_lines (guestfs_h *g, const char *command); This is the same as "guestfs_sh", but splits the result into a list of lines. See also: "guestfs_command_lines" This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.0.50) guestfs_sleep int guestfs_sleep (guestfs_h *g, int secs); Sleep for "secs" seconds. This function returns 0 on success or -1 on error. (Added in 1.0.41) guestfs_stat struct guestfs_stat * guestfs_stat (guestfs_h *g, const char *path); Returns file information for the given "path". This is the same as the stat(2) system call. This function returns a "struct guestfs_stat *", or NULL if there was an error. The caller must call "guestfs_free_stat" after use. (Added in 0.9.2) guestfs_statvfs struct guestfs_statvfs * guestfs_statvfs (guestfs_h *g, const char *path); Returns file system statistics for any mounted file system. "path" should be a file or directory in the mounted file system (typically it is the mount point itself, but it doesn't need to be). This is the same as the statvfs(2) system call. This function returns a "struct guestfs_statvfs *", or NULL if there was an error. The caller must call "guestfs_free_statvfs" after use. (Added in 0.9.2) guestfs_strings char ** guestfs_strings (guestfs_h *g, const char *path); This runs the strings(1) command on a file and returns the list of printable strings found. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.22) guestfs_strings_e char ** guestfs_strings_e (guestfs_h *g, const char *encoding, const char *path); This is like the "guestfs_strings" command, but allows you to specify the encoding of strings that are looked for in the source file "path". Allowed encodings are: s Single 7-bit-byte characters like ASCII and the ASCII-compatible parts of ISO-8859-X (this is what "guestfs_strings" uses). S Single 8-bit-byte characters. b 16-bit big endian strings such as those encoded in UTF-16BE or UCS-2BE. l (lower case letter L) 16-bit little endian such as UTF-16LE and UCS-2LE. This is useful for examining binaries in Windows guests. B 32-bit big endian such as UCS-4BE. L 32-bit little endian such as UCS-4LE. The returned strings are transcoded to UTF-8. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.22) guestfs_swapoff_device int guestfs_swapoff_device (guestfs_h *g, const char *device); This command disables the libguestfs appliance swap device or partition named "device". See "guestfs_swapon_device". This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_swapoff_file int guestfs_swapoff_file (guestfs_h *g, const char *file); This command disables the libguestfs appliance swap on file. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_swapoff_label int guestfs_swapoff_label (guestfs_h *g, const char *label); This command disables the libguestfs appliance swap on labeled swap partition. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_swapoff_uuid int guestfs_swapoff_uuid (guestfs_h *g, const char *uuid); This command disables the libguestfs appliance swap partition with the given UUID. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_swapon_device int guestfs_swapon_device (guestfs_h *g, const char *device); This command enables the libguestfs appliance to use the swap device or partition named "device". The increased memory is made available for all commands, for example those run using "guestfs_command" or "guestfs_sh". Note that you should not swap to existing guest swap partitions unless you know what you are doing. They may contain hibernation information, or other information that the guest doesn't want you to trash. You also risk leaking information about the host to the guest this way. Instead, attach a new host device to the guest and swap on that. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_swapon_file int guestfs_swapon_file (guestfs_h *g, const char *file); This command enables swap to a file. See "guestfs_swapon_device" for other notes. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_swapon_label int guestfs_swapon_label (guestfs_h *g, const char *label); This command enables swap to a labeled swap partition. See "guestfs_swapon_device" for other notes. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_swapon_uuid int guestfs_swapon_uuid (guestfs_h *g, const char *uuid); This command enables swap to a swap partition with the given UUID. See "guestfs_swapon_device" for other notes. This function returns 0 on success or -1 on error. (Added in 1.0.66) guestfs_sync int guestfs_sync (guestfs_h *g); This syncs the disk, so that any writes are flushed through to the underlying disk image. You should always call this if you have modified a disk image, before closing the handle. This function returns 0 on success or -1 on error. (Added in 0.3) guestfs_tail char ** guestfs_tail (guestfs_h *g, const char *path); This command returns up to the last 10 lines of a file as a list of strings. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.54) guestfs_tail_n char ** guestfs_tail_n (guestfs_h *g, int nrlines, const char *path); If the parameter "nrlines" is a positive number, this returns the last "nrlines" lines of the file "path". If the parameter "nrlines" is a negative number, this returns lines from the file "path", starting with the "-nrlines"th line. If the parameter "nrlines" is zero, this returns an empty list. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.54) guestfs_tar_in int guestfs_tar_in (guestfs_h *g, const char *tarfile, const char *directory); This command uploads and unpacks local file "tarfile" (an uncompressed tar file) into "directory". To upload a compressed tarball, use "guestfs_tgz_in" or "guestfs_txz_in". This function returns 0 on success or -1 on error. (Added in 1.0.3) guestfs_tar_out int guestfs_tar_out (guestfs_h *g, const char *directory, const char *tarfile); This command packs the contents of "directory" and downloads it to local file "tarfile". To download a compressed tarball, use "guestfs_tgz_out" or "guestfs_txz_out". This function returns 0 on success or -1 on error. (Added in 1.0.3) guestfs_tgz_in int guestfs_tgz_in (guestfs_h *g, const char *tarball, const char *directory); This command uploads and unpacks local file "tarball" (a gzip compressed tar file) into "directory". To upload an uncompressed tarball, use "guestfs_tar_in". This function returns 0 on success or -1 on error. (Added in 1.0.3) guestfs_tgz_out int guestfs_tgz_out (guestfs_h *g, const char *directory, const char *tarball); This command packs the contents of "directory" and downloads it to local file "tarball". To download an uncompressed tarball, use "guestfs_tar_out". This function returns 0 on success or -1 on error. (Added in 1.0.3) guestfs_touch int guestfs_touch (guestfs_h *g, const char *path); Touch acts like the touch(1) command. It can be used to update the timestamps on a file, or, if the file does not exist, to create a new zero-length file. This command only works on regular files, and will fail on other file types such as directories, symbolic links, block special etc. This function returns 0 on success or -1 on error. (Added in 0.3) guestfs_truncate int guestfs_truncate (guestfs_h *g, const char *path); This command truncates "path" to a zero-length file. The file must exist already. This function returns 0 on success or -1 on error. (Added in 1.0.77) guestfs_truncate_size int guestfs_truncate_size (guestfs_h *g, const char *path, int64_t size); This command truncates "path" to size "size" bytes. The file must exist already. If the current file size is less than "size" then the file is extended to the required size with zero bytes. This creates a sparse file (ie. disk blocks are not allocated for the file until you write to it). To create a non-sparse file of zeroes, use "guestfs_fallocate64" instead. This function returns 0 on success or -1 on error. (Added in 1.0.77) guestfs_tune2fs int guestfs_tune2fs (guestfs_h *g, const char *device, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_TUNE2FS_FORCE, int force, GUESTFS_TUNE2FS_MAXMOUNTCOUNT, int maxmountcount, GUESTFS_TUNE2FS_MOUNTCOUNT, int mountcount, GUESTFS_TUNE2FS_ERRORBEHAVIOR, const char *errorbehavior, GUESTFS_TUNE2FS_GROUP, int64_t group, GUESTFS_TUNE2FS_INTERVALBETWEENCHECKS, int intervalbetweenchecks, GUESTFS_TUNE2FS_RESERVEDBLOCKSPERCENTAGE, int reservedblockspercentage, GUESTFS_TUNE2FS_LASTMOUNTEDDIRECTORY, const char *lastmounteddirectory, GUESTFS_TUNE2FS_RESERVEDBLOCKSCOUNT, int64_t reservedblockscount, GUESTFS_TUNE2FS_USER, int64_t user, This call allows you to adjust various filesystem parameters of an ext2/ext3/ext4 filesystem called "device". The optional parameters are: "force" Force tune2fs to complete the operation even in the face of errors. This is the same as the tune2fs "-f" option. "maxmountcount" Set the number of mounts after which the filesystem is checked by e2fsck(8). If this is 0 then the number of mounts is disregarded. This is the same as the tune2fs "-c" option. "mountcount" Set the number of times the filesystem has been mounted. This is the same as the tune2fs "-C" option. "errorbehavior" Change the behavior of the kernel code when errors are detected. Possible values currently are: "continue", "remount-ro", "panic". In practice these options don't really make any difference, particularly for write errors. This is the same as the tune2fs "-e" option. "group" Set the group which can use reserved filesystem blocks. This is the same as the tune2fs "-g" option except that it can only be specified as a number. "intervalbetweenchecks" Adjust the maximal time between two filesystem checks (in seconds). If the option is passed as 0 then time-dependent checking is disabled. This is the same as the tune2fs "-i" option. "reservedblockspercentage" Set the percentage of the filesystem which may only be allocated by privileged processes. This is the same as the tune2fs "-m" option. "lastmounteddirectory" Set the last mounted directory. This is the same as the tune2fs "-M" option. "reservedblockscount" Set the number of reserved filesystem blocks. This is the same as the tune2fs "-r" option. "user" Set the user who can use the reserved filesystem blocks. This is the same as the tune2fs "-u" option except that it can only be specified as a number. To get the current values of filesystem parameters, see "guestfs_tune2fs_l". For precise details of how tune2fs works, see the tune2fs(8) man page. This function returns 0 on success or -1 on error. (Added in 1.15.4) guestfs_tune2fs_va int guestfs_tune2fs_va (guestfs_h *g, const char *device, va_list args); This is the "va_list variant" of "guestfs_tune2fs". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_tune2fs_argv int guestfs_tune2fs_argv (guestfs_h *g, const char *device, const struct guestfs_tune2fs_argv *optargs); This is the "argv variant" of "guestfs_tune2fs". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_tune2fs_l char ** guestfs_tune2fs_l (guestfs_h *g, const char *device); This returns the contents of the ext2, ext3 or ext4 filesystem superblock on "device". It is the same as running "tune2fs -l device". See tune2fs(8) manpage for more details. The list of fields returned isn't clearly defined, and depends on both the version of "tune2fs" that libguestfs was built against, and the filesystem itself. This function returns a NULL-terminated array of strings, or NULL if there was an error. The array of strings will always have length "2n+1", where "n" keys and values alternate, followed by the trailing NULL entry. The caller must free the strings and the array after use. (Added in 0.9.2) guestfs_txz_in int guestfs_txz_in (guestfs_h *g, const char *tarball, const char *directory); This command uploads and unpacks local file "tarball" (an xz compressed tar file) into "directory". This function returns 0 on success or -1 on error. (Added in 1.3.2) guestfs_txz_out int guestfs_txz_out (guestfs_h *g, const char *directory, const char *tarball); This command packs the contents of "directory" and downloads it to local file "tarball" (as an xz compressed tar archive). This function returns 0 on success or -1 on error. (Added in 1.3.2) guestfs_umask int guestfs_umask (guestfs_h *g, int mask); This function sets the mask used for creating new files and device nodes to "mask & 0777". Typical umask values would be 022 which creates new files with permissions like "-rw-r--r--" or "-rwxr-xr-x", and 002 which creates new files with permissions like "-rw-rw-r--" or "-rwxrwxr-x". The default umask is 022. This is important because it means that directories and device nodes will be created with 0644 or 0755 mode even if you specify 0777. See also "guestfs_get_umask", umask(2), "guestfs_mknod", "guestfs_mkdir". This call returns the previous umask. On error this function returns -1. (Added in 1.0.55) guestfs_umount int guestfs_umount (guestfs_h *g, const char *pathordevice); This unmounts the given filesystem. The filesystem may be specified either by its mountpoint (path) or the device which contains the filesystem. This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_umount_all int guestfs_umount_all (guestfs_h *g); This unmounts all mounted filesystems. Some internal mounts are not unmounted by this call. This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_umount_local int guestfs_umount_local (guestfs_h *g, ...); You may supply a list of optional arguments to this call. Use zero or more of the following pairs of parameters, and terminate the list with "-1" on its own. See "CALLS WITH OPTIONAL ARGUMENTS". GUESTFS_UMOUNT_LOCAL_RETRY, int retry, If libguestfs is exporting the filesystem on a local mountpoint, then this unmounts it. See "MOUNT LOCAL" in guestfs(3) for full documentation. This function returns 0 on success or -1 on error. (Added in 1.17.22) guestfs_umount_local_va int guestfs_umount_local_va (guestfs_h *g, va_list args); This is the "va_list variant" of "guestfs_umount_local". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_umount_local_argv int guestfs_umount_local_argv (guestfs_h *g, const struct guestfs_umount_local_argv *optargs); This is the "argv variant" of "guestfs_umount_local". See "CALLS WITH OPTIONAL ARGUMENTS". guestfs_upload int guestfs_upload (guestfs_h *g, const char *filename, const char *remotefilename); Upload local file "filename" to "remotefilename" on the filesystem. "filename" can also be a named pipe. See also "guestfs_download". This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.0.2) guestfs_upload_offset int guestfs_upload_offset (guestfs_h *g, const char *filename, const char *remotefilename, int64_t offset); Upload local file "filename" to "remotefilename" on the filesystem. "remotefilename" is overwritten starting at the byte "offset" specified. The intention is to overwrite parts of existing files or devices, although if a non-existant file is specified then it is created with a "hole" before "offset". The size of the data written is implicit in the size of the source "filename". Note that there is no limit on the amount of data that can be uploaded with this call, unlike with "guestfs_pwrite", and this call always writes the full amount unless an error occurs. See also "guestfs_upload", "guestfs_pwrite". This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.5.17) guestfs_utimens int guestfs_utimens (guestfs_h *g, const char *path, int64_t atsecs, int64_t atnsecs, int64_t mtsecs, int64_t mtnsecs); This command sets the timestamps of a file with nanosecond precision. "atsecs, atnsecs" are the last access time (atime) in secs and nanoseconds from the epoch. "mtsecs, mtnsecs" are the last modification time (mtime) in secs and nanoseconds from the epoch. If the *nsecs field contains the special value "-1" then the corresponding timestamp is set to the current time. (The *secs field is ignored in this case). If the *nsecs field contains the special value "-2" then the corresponding timestamp is left unchanged. (The *secs field is ignored in this case). This function returns 0 on success or -1 on error. (Added in 1.0.77) guestfs_version struct guestfs_version * guestfs_version (guestfs_h *g); Return the libguestfs version number that the program is linked against. Note that because of dynamic linking this is not necessarily the version of libguestfs that you compiled against. You can compile the program, and then at runtime dynamically link against a completely different "libguestfs.so" library. This call was added in version 1.0.58. In previous versions of libguestfs there was no way to get the version number. From C code you can use dynamic linker functions to find out if this symbol exists (if it doesn't, then it's an earlier version). The call returns a structure with four elements. The first three ("major", "minor" and "release") are numbers and correspond to the usual version triplet. The fourth element ("extra") is a string and is normally empty, but may be used for distro-specific information. To construct the original version string: "$major.$minor.$release$extra" See also: "LIBGUESTFS VERSION NUMBERS" in guestfs(3). Note: Don't use this call to test for availability of features. In enterprise distributions we backport features from later versions into earlier versions, making this an unreliable way to test for features. Use "guestfs_available" instead. This function returns a "struct guestfs_version *", or NULL if there was an error. The caller must call "guestfs_free_version" after use. (Added in 1.0.58) guestfs_vfs_label char * guestfs_vfs_label (guestfs_h *g, const char *device); This returns the filesystem label of the filesystem on "device". If the filesystem is unlabeled, this returns the empty string. To find a filesystem from the label, use "guestfs_findfs_label". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.3.18) guestfs_vfs_type char * guestfs_vfs_type (guestfs_h *g, const char *device); This command gets the filesystem type corresponding to the filesystem on "device". For most filesystems, the result is the name of the Linux VFS module which would be used to mount this filesystem if you mounted it without specifying the filesystem type. For example a string such as "ext3" or "ntfs". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.75) guestfs_vfs_uuid char * guestfs_vfs_uuid (guestfs_h *g, const char *device); This returns the filesystem UUID of the filesystem on "device". If the filesystem does not have a UUID, this returns the empty string. To find a filesystem from the UUID, use "guestfs_findfs_uuid". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.3.18) guestfs_vg_activate int guestfs_vg_activate (guestfs_h *g, int activate, char *const *volgroups); This command activates or (if "activate" is false) deactivates all logical volumes in the listed volume groups "volgroups". This command is the same as running "vgchange -a y|n volgroups..." Note that if "volgroups" is an empty list then all volume groups are activated or deactivated. This function returns 0 on success or -1 on error. (Added in 1.0.26) guestfs_vg_activate_all int guestfs_vg_activate_all (guestfs_h *g, int activate); This command activates or (if "activate" is false) deactivates all logical volumes in all volume groups. This command is the same as running "vgchange -a y|n" This function returns 0 on success or -1 on error. (Added in 1.0.26) guestfs_vgcreate int guestfs_vgcreate (guestfs_h *g, const char *volgroup, char *const *physvols); This creates an LVM volume group called "volgroup" from the non-empty list of physical volumes "physvols". This function returns 0 on success or -1 on error. (Added in 0.8) guestfs_vglvuuids char ** guestfs_vglvuuids (guestfs_h *g, const char *vgname); Given a VG called "vgname", this returns the UUIDs of all the logical volumes created in this volume group. You can use this along with "guestfs_lvs" and "guestfs_lvuuid" calls to associate logical volumes and volume groups. See also "guestfs_vgpvuuids". This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.0.87) guestfs_vgmeta char * guestfs_vgmeta (guestfs_h *g, const char *vgname, size_t *size_r); "vgname" is an LVM volume group. This command examines the volume group and returns its metadata. Note that the metadata is an internal structure used by LVM, subject to change at any time, and is provided for information only. This function returns a buffer, or NULL on error. The size of the returned buffer is written to *size_r. The caller must free the returned buffer after use. (Added in 1.17.20) guestfs_vgpvuuids char ** guestfs_vgpvuuids (guestfs_h *g, const char *vgname); Given a VG called "vgname", this returns the UUIDs of all the physical volumes that this volume group resides on. You can use this along with "guestfs_pvs" and "guestfs_pvuuid" calls to associate physical volumes and volume groups. See also "guestfs_vglvuuids". This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 1.0.87) guestfs_vgremove int guestfs_vgremove (guestfs_h *g, const char *vgname); Remove an LVM volume group "vgname", (for example "VG"). This also forcibly removes all logical volumes in the volume group (if any). This function returns 0 on success or -1 on error. (Added in 1.0.13) guestfs_vgrename int guestfs_vgrename (guestfs_h *g, const char *volgroup, const char *newvolgroup); Rename a volume group "volgroup" with the new name "newvolgroup". This function returns 0 on success or -1 on error. (Added in 1.0.83) guestfs_vgs char ** guestfs_vgs (guestfs_h *g); List all the volumes groups detected. This is the equivalent of the vgs(8) command. This returns a list of just the volume group names that were detected (eg. "VolGroup00"). See also "guestfs_vgs_full". This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. (Added in 0.4) guestfs_vgs_full struct guestfs_lvm_vg_list * guestfs_vgs_full (guestfs_h *g); List all the volumes groups detected. This is the equivalent of the vgs(8) command. The "full" version includes all fields. This function returns a "struct guestfs_lvm_vg_list *", or NULL if there was an error. The caller must call "guestfs_free_lvm_vg_list" after use. (Added in 0.4) guestfs_vgscan int guestfs_vgscan (guestfs_h *g); This rescans all block devices and rebuilds the list of LVM physical volumes, volume groups and logical volumes. This function returns 0 on success or -1 on error. (Added in 1.3.2) guestfs_vguuid char * guestfs_vguuid (guestfs_h *g, const char *vgname); This command returns the UUID of the LVM VG named "vgname". This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.87) guestfs_wait_ready int guestfs_wait_ready (guestfs_h *g); This function is deprecated. In new code, use the "guestfs_launch" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This function is a no op. In versions of the API < 1.0.71 you had to call this function just after calling "guestfs_launch" to wait for the launch to complete. However this is no longer necessary because "guestfs_launch" now does the waiting. If you see any calls to this function in code then you can just remove them, unless you want to retain compatibility with older versions of the API. This function returns 0 on success or -1 on error. (Added in 0.3) guestfs_wc_c int guestfs_wc_c (guestfs_h *g, const char *path); This command counts the characters in a file, using the "wc -c" external command. On error this function returns -1. (Added in 1.0.54) guestfs_wc_l int guestfs_wc_l (guestfs_h *g, const char *path); This command counts the lines in a file, using the "wc -l" external command. On error this function returns -1. (Added in 1.0.54) guestfs_wc_w int guestfs_wc_w (guestfs_h *g, const char *path); This command counts the words in a file, using the "wc -w" external command. On error this function returns -1. (Added in 1.0.54) guestfs_wipefs int guestfs_wipefs (guestfs_h *g, const char *device); This command erases filesystem or RAID signatures from the specified "device" to make the filesystem invisible to libblkid. This does not erase the filesystem itself nor any other data from the "device". Compare with "guestfs_zero" which zeroes the first few blocks of a device. This function returns 0 on success or -1 on error. (Added in 1.17.6) guestfs_write int guestfs_write (guestfs_h *g, const char *path, const char *content, size_t content_size); This call creates a file called "path". The content of the file is the string "content" (which can contain any 8 bit data). See also "guestfs_write_append". This function returns 0 on success or -1 on error. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.3.14) guestfs_write_append int guestfs_write_append (guestfs_h *g, const char *path, const char *content, size_t content_size); This call appends "content" to the end of file "path". If "path" does not exist, then a new file is created. See also "guestfs_write". This function returns 0 on success or -1 on error. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.11.18) guestfs_write_file int guestfs_write_file (guestfs_h *g, const char *path, const char *content, int size); This function is deprecated. In new code, use the "guestfs_write" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This call creates a file called "path". The contents of the file is the string "content" (which can contain any 8 bit data), with length "size". As a special case, if "size" is 0 then the length is calculated using "strlen" (so in this case the content cannot contain embedded ASCII NULs). NB. Owing to a bug, writing content containing ASCII NUL characters does not work, even if the length is specified. This function returns 0 on success or -1 on error. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 0.8) guestfs_zegrep char ** guestfs_zegrep (guestfs_h *g, const char *regex, const char *path); This calls the external "zegrep" program and returns the matching lines. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.66) guestfs_zegrepi char ** guestfs_zegrepi (guestfs_h *g, const char *regex, const char *path); This calls the external "zegrep -i" program and returns the matching lines. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.66) guestfs_zero int guestfs_zero (guestfs_h *g, const char *device); This command writes zeroes over the first few blocks of "device". How many blocks are zeroed isn't specified (but it's not enough to securely wipe the device). It should be sufficient to remove any partition tables, filesystem superblocks and so on. If blocks are already zero, then this command avoids writing zeroes. This prevents the underlying device from becoming non-sparse or growing unnecessarily. See also: "guestfs_zero_device", "guestfs_scrub_device", "guestfs_is_zero_device" This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.0.16) guestfs_zero_device int guestfs_zero_device (guestfs_h *g, const char *device); This command writes zeroes over the entire "device". Compare with "guestfs_zero" which just zeroes the first few blocks of a device. If blocks are already zero, then this command avoids writing zeroes. This prevents the underlying device from becoming non-sparse or growing unnecessarily. This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.3.1) guestfs_zero_free_space int guestfs_zero_free_space (guestfs_h *g, const char *directory); Zero the free space in the filesystem mounted on "directory". The filesystem must be mounted read-write. The filesystem contents are not affected, but any free space in the filesystem is freed. In future (but not currently) these zeroed blocks will be "sparsified" - that is, given back to the host. This function returns 0 on success or -1 on error. This long-running command can generate progress notification messages so that the caller can display a progress bar or indicator. To receive these messages, the caller must register a progress event callback. See "GUESTFS_EVENT_PROGRESS" in guestfs(3). (Added in 1.17.18) guestfs_zerofree int guestfs_zerofree (guestfs_h *g, const char *device); This runs the zerofree program on "device". This program claims to zero unused inodes and disk blocks on an ext2/3 filesystem, thus making it possible to compress the filesystem more effectively. You should not run this program if the filesystem is mounted. It is possible that using this program can damage the filesystem or data on the filesystem. This function returns 0 on success or -1 on error. (Added in 1.0.26) guestfs_zfgrep char ** guestfs_zfgrep (guestfs_h *g, const char *pattern, const char *path); This calls the external "zfgrep" program and returns the matching lines. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.66) guestfs_zfgrepi char ** guestfs_zfgrepi (guestfs_h *g, const char *pattern, const char *path); This calls the external "zfgrep -i" program and returns the matching lines. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.66) guestfs_zfile char * guestfs_zfile (guestfs_h *g, const char *meth, const char *path); This function is deprecated. In new code, use the "guestfs_file" call instead. Deprecated functions will not be removed from the API, but the fact that they are deprecated indicates that there are problems with correct use of these functions. This command runs "file" after first decompressing "path" using "method". "method" must be one of "gzip", "compress" or "bzip2". Since 1.0.63, use "guestfs_file" instead which can now process compressed files. This function returns a string, or NULL on error. The caller must free the returned string after use. (Added in 1.0.59) guestfs_zgrep char ** guestfs_zgrep (guestfs_h *g, const char *regex, const char *path); This calls the external "zgrep" program and returns the matching lines. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.66) guestfs_zgrepi char ** guestfs_zgrepi (guestfs_h *g, const char *regex, const char *path); This calls the external "zgrep -i" program and returns the matching lines. This function returns a NULL-terminated array of strings (like environ(3)), or NULL if there was an error. The caller must free the strings and the array after use. Because of the message protocol, there is a transfer limit of somewhere between 2MB and 4MB. See "PROTOCOL LIMITS" in guestfs(3). (Added in 1.0.66) STRUCTURES
guestfs_int_bool struct guestfs_int_bool { int32_t i; int32_t b; }; struct guestfs_int_bool_list { uint32_t len; /* Number of elements in list. */ struct guestfs_int_bool *val; /* Elements. */ }; void guestfs_free_int_bool (struct guestfs_free_int_bool *); void guestfs_free_int_bool_list (struct guestfs_free_int_bool_list *); guestfs_lvm_pv struct guestfs_lvm_pv { char *pv_name; /* The next field is NOT nul-terminated, be careful when printing it: */ char pv_uuid[32]; char *pv_fmt; uint64_t pv_size; uint64_t dev_size; uint64_t pv_free; uint64_t pv_used; char *pv_attr; int64_t pv_pe_count; int64_t pv_pe_alloc_count; char *pv_tags; uint64_t pe_start; int64_t pv_mda_count; uint64_t pv_mda_free; }; struct guestfs_lvm_pv_list { uint32_t len; /* Number of elements in list. */ struct guestfs_lvm_pv *val; /* Elements. */ }; void guestfs_free_lvm_pv (struct guestfs_free_lvm_pv *); void guestfs_free_lvm_pv_list (struct guestfs_free_lvm_pv_list *); guestfs_lvm_vg struct guestfs_lvm_vg { char *vg_name; /* The next field is NOT nul-terminated, be careful when printing it: */ char vg_uuid[32]; char *vg_fmt; char *vg_attr; uint64_t vg_size; uint64_t vg_free; char *vg_sysid; uint64_t vg_extent_size; int64_t vg_extent_count; int64_t vg_free_count; int64_t max_lv; int64_t max_pv; int64_t pv_count; int64_t lv_count; int64_t snap_count; int64_t vg_seqno; char *vg_tags; int64_t vg_mda_count; uint64_t vg_mda_free; }; struct guestfs_lvm_vg_list { uint32_t len; /* Number of elements in list. */ struct guestfs_lvm_vg *val; /* Elements. */ }; void guestfs_free_lvm_vg (struct guestfs_free_lvm_vg *); void guestfs_free_lvm_vg_list (struct guestfs_free_lvm_vg_list *); guestfs_lvm_lv struct guestfs_lvm_lv { char *lv_name; /* The next field is NOT nul-terminated, be careful when printing it: */ char lv_uuid[32]; char *lv_attr; int64_t lv_major; int64_t lv_minor; int64_t lv_kernel_major; int64_t lv_kernel_minor; uint64_t lv_size; int64_t seg_count; char *origin; /* The next field is [0..100] or -1 meaning 'not present': */ float snap_percent; /* The next field is [0..100] or -1 meaning 'not present': */ float copy_percent; char *move_pv; char *lv_tags; char *mirror_log; char *modules; }; struct guestfs_lvm_lv_list { uint32_t len; /* Number of elements in list. */ struct guestfs_lvm_lv *val; /* Elements. */ }; void guestfs_free_lvm_lv (struct guestfs_free_lvm_lv *); void guestfs_free_lvm_lv_list (struct guestfs_free_lvm_lv_list *); guestfs_stat struct guestfs_stat { int64_t dev; int64_t ino; int64_t mode; int64_t nlink; int64_t uid; int64_t gid; int64_t rdev; int64_t size; int64_t blksize; int64_t blocks; int64_t atime; int64_t mtime; int64_t ctime; }; struct guestfs_stat_list { uint32_t len; /* Number of elements in list. */ struct guestfs_stat *val; /* Elements. */ }; void guestfs_free_stat (struct guestfs_free_stat *); void guestfs_free_stat_list (struct guestfs_free_stat_list *); guestfs_statvfs struct guestfs_statvfs { int64_t bsize; int64_t frsize; int64_t blocks; int64_t bfree; int64_t bavail; int64_t files; int64_t ffree; int64_t favail; int64_t fsid; int64_t flag; int64_t namemax; }; struct guestfs_statvfs_list { uint32_t len; /* Number of elements in list. */ struct guestfs_statvfs *val; /* Elements. */ }; void guestfs_free_statvfs (struct guestfs_free_statvfs *); void guestfs_free_statvfs_list (struct guestfs_free_statvfs_list *); guestfs_dirent struct guestfs_dirent { int64_t ino; char ftyp; char *name; }; struct guestfs_dirent_list { uint32_t len; /* Number of elements in list. */ struct guestfs_dirent *val; /* Elements. */ }; void guestfs_free_dirent (struct guestfs_free_dirent *); void guestfs_free_dirent_list (struct guestfs_free_dirent_list *); guestfs_version struct guestfs_version { int64_t major; int64_t minor; int64_t release; char *extra; }; struct guestfs_version_list { uint32_t len; /* Number of elements in list. */ struct guestfs_version *val; /* Elements. */ }; void guestfs_free_version (struct guestfs_free_version *); void guestfs_free_version_list (struct guestfs_free_version_list *); guestfs_xattr struct guestfs_xattr { char *attrname; /* The next two fields describe a byte array. */ uint32_t attrval_len; char *attrval; }; struct guestfs_xattr_list { uint32_t len; /* Number of elements in list. */ struct guestfs_xattr *val; /* Elements. */ }; void guestfs_free_xattr (struct guestfs_free_xattr *); void guestfs_free_xattr_list (struct guestfs_free_xattr_list *); guestfs_inotify_event struct guestfs_inotify_event { int64_t in_wd; uint32_t in_mask; uint32_t in_cookie; char *in_name; }; struct guestfs_inotify_event_list { uint32_t len; /* Number of elements in list. */ struct guestfs_inotify_event *val; /* Elements. */ }; void guestfs_free_inotify_event (struct guestfs_free_inotify_event *); void guestfs_free_inotify_event_list (struct guestfs_free_inotify_event_list *); guestfs_partition struct guestfs_partition { int32_t part_num; uint64_t part_start; uint64_t part_end; uint64_t part_size; }; struct guestfs_partition_list { uint32_t len; /* Number of elements in list. */ struct guestfs_partition *val; /* Elements. */ }; void guestfs_free_partition (struct guestfs_free_partition *); void guestfs_free_partition_list (struct guestfs_free_partition_list *); guestfs_application struct guestfs_application { char *app_name; char *app_display_name; int32_t app_epoch; char *app_version; char *app_release; char *app_install_path; char *app_trans_path; char *app_publisher; char *app_url; char *app_source_package; char *app_summary; char *app_description; }; struct guestfs_application_list { uint32_t len; /* Number of elements in list. */ struct guestfs_application *val; /* Elements. */ }; void guestfs_free_application (struct guestfs_free_application *); void guestfs_free_application_list (struct guestfs_free_application_list *); guestfs_isoinfo struct guestfs_isoinfo { char *iso_system_id; char *iso_volume_id; uint32_t iso_volume_space_size; uint32_t iso_volume_set_size; uint32_t iso_volume_sequence_number; uint32_t iso_logical_block_size; char *iso_volume_set_id; char *iso_publisher_id; char *iso_data_preparer_id; char *iso_application_id; char *iso_copyright_file_id; char *iso_abstract_file_id; char *iso_bibliographic_file_id; int64_t iso_volume_creation_t; int64_t iso_volume_modification_t; int64_t iso_volume_expiration_t; int64_t iso_volume_effective_t; }; struct guestfs_isoinfo_list { uint32_t len; /* Number of elements in list. */ struct guestfs_isoinfo *val; /* Elements. */ }; void guestfs_free_isoinfo (struct guestfs_free_isoinfo *); void guestfs_free_isoinfo_list (struct guestfs_free_isoinfo_list *); guestfs_mdstat struct guestfs_mdstat { char *mdstat_device; int32_t mdstat_index; char *mdstat_flags; }; struct guestfs_mdstat_list { uint32_t len; /* Number of elements in list. */ struct guestfs_mdstat *val; /* Elements. */ }; void guestfs_free_mdstat (struct guestfs_free_mdstat *); void guestfs_free_mdstat_list (struct guestfs_free_mdstat_list *); guestfs_btrfssubvolume struct guestfs_btrfssubvolume { uint64_t btrfssubvolume_id; uint64_t btrfssubvolume_top_level_id; char *btrfssubvolume_path; }; struct guestfs_btrfssubvolume_list { uint32_t len; /* Number of elements in list. */ struct guestfs_btrfssubvolume *val; /* Elements. */ }; void guestfs_free_btrfssubvolume (struct guestfs_free_btrfssubvolume *); void guestfs_free_btrfssubvolume_list (struct guestfs_free_btrfssubvolume_list *); AVAILABILITY
GROUPS OF FUNCTIONALITY IN THE APPLIANCE Using "guestfs_available" you can test availability of the following groups of functions. This test queries the appliance to see if the appliance you are currently using supports the functionality. augeas The following functions: "guestfs_aug_clear" "guestfs_aug_close" "guestfs_aug_defnode" "guestfs_aug_defvar" "guestfs_aug_get" "guestfs_aug_init" "guestfs_aug_insert" "guestfs_aug_load" "guestfs_aug_ls" "guestfs_aug_match" "guestfs_aug_mv" "guestfs_aug_rm" "guestfs_aug_save" "guestfs_aug_set" btrfs The following functions: "guestfs_btrfs_device_add" "guestfs_btrfs_device_delete" "guestfs_btrfs_filesystem_balance" "guestfs_btrfs_filesystem_resize" "guestfs_btrfs_filesystem_sync" "guestfs_btrfs_fsck" "guestfs_btrfs_set_seeding" "guestfs_btrfs_subvolume_create" "guestfs_btrfs_subvolume_delete" "guestfs_btrfs_subvolume_list" "guestfs_btrfs_subvolume_set_default" "guestfs_btrfs_subvolume_snapshot" "guestfs_mkfs_btrfs" grub The following functions: "guestfs_grub_install" inotify The following functions: "guestfs_inotify_add_watch" "guestfs_inotify_close" "guestfs_inotify_files" "guestfs_inotify_init" "guestfs_inotify_read" "guestfs_inotify_rm_watch" linuxfsuuid The following functions: "guestfs_mke2fs_JU" "guestfs_mke2journal_U" "guestfs_mkswap_U" "guestfs_swapoff_uuid" "guestfs_swapon_uuid" linuxmodules The following functions: "guestfs_modprobe" linuxxattrs The following functions: "guestfs_getxattr" "guestfs_getxattrs" "guestfs_lgetxattr" "guestfs_lgetxattrs" "guestfs_lremovexattr" "guestfs_lsetxattr" "guestfs_lxattrlist" "guestfs_removexattr" "guestfs_setxattr" luks The following functions: "guestfs_luks_add_key" "guestfs_luks_close" "guestfs_luks_format" "guestfs_luks_format_cipher" "guestfs_luks_kill_slot" "guestfs_luks_open" "guestfs_luks_open_ro" lvm2 The following functions: "guestfs_is_lv" "guestfs_lvcreate" "guestfs_lvcreate_free" "guestfs_lvm_remove_all" "guestfs_lvm_set_filter" "guestfs_lvremove" "guestfs_lvresize" "guestfs_lvresize_free" "guestfs_lvs" "guestfs_lvs_full" "guestfs_pvcreate" "guestfs_pvremove" "guestfs_pvresize" "guestfs_pvresize_size" "guestfs_pvs" "guestfs_pvs_full" "guestfs_vg_activate" "guestfs_vg_activate_all" "guestfs_vgcreate" "guestfs_vgmeta" "guestfs_vgremove" "guestfs_vgs" "guestfs_vgs_full" mdadm The following functions: "guestfs_md_create" "guestfs_md_detail" "guestfs_md_stat" "guestfs_md_stop" mknod The following functions: "guestfs_mkfifo" "guestfs_mknod" "guestfs_mknod_b" "guestfs_mknod_c" ntfs3g The following functions: "guestfs_ntfs_3g_probe" "guestfs_ntfsclone_in" "guestfs_ntfsclone_out" "guestfs_ntfsfix" ntfsprogs The following functions: "guestfs_ntfsresize" "guestfs_ntfsresize_opts" "guestfs_ntfsresize_size" realpath The following functions: "guestfs_realpath" scrub The following functions: "guestfs_scrub_device" "guestfs_scrub_file" "guestfs_scrub_freespace" selinux The following functions: "guestfs_getcon" "guestfs_setcon" wipefs The following functions: "guestfs_wipefs" xz The following functions: "guestfs_txz_in" "guestfs_txz_out" zerofree The following functions: "guestfs_zerofree" GUESTFISH supported COMMAND In guestfish(3) there is a handy interactive command "supported" which prints out the available groups and whether they are supported by this build of libguestfs. Note however that you have to do "run" first. SINGLE CALLS AT COMPILE TIME Since version 1.5.8, "<guestfs.h>" defines symbols for each C API function, such as: #define LIBGUESTFS_HAVE_DD 1 if "guestfs_dd" is available. Before version 1.5.8, if you needed to test whether a single libguestfs function is available at compile time, we recommended using build tools such as autoconf or cmake. For example in autotools you could use: AC_CHECK_LIB([guestfs],[guestfs_create]) AC_CHECK_FUNCS([guestfs_dd]) which would result in "HAVE_GUESTFS_DD" being either defined or not defined in your program. SINGLE CALLS AT RUN TIME Testing at compile time doesn't guarantee that a function really exists in the library. The reason is that you might be dynamically linked against a previous libguestfs.so (dynamic library) which doesn't have the call. This situation unfortunately results in a segmentation fault, which is a shortcoming of the C dynamic linking system itself. You can use dlopen(3) to test if a function is available at run time, as in this example program (note that you still need the compile time check as well): #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <dlfcn.h> #include <guestfs.h> main () { #ifdef LIBGUESTFS_HAVE_DD void *dl; int has_function; /* Test if the function guestfs_dd is really available. */ dl = dlopen (NULL, RTLD_LAZY); if (!dl) { fprintf (stderr, "dlopen: %s ", dlerror ()); exit (EXIT_FAILURE); } has_function = dlsym (dl, "guestfs_dd") != NULL; dlclose (dl); if (!has_function) printf ("this libguestfs.so does NOT have guestfs_dd function "); else { printf ("this libguestfs.so has guestfs_dd function "); /* Now it's safe to call guestfs_dd (g, "foo", "bar"); */ } #else printf ("guestfs_dd function was not found at compile time "); #endif } You may think the above is an awful lot of hassle, and it is. There are other ways outside of the C linking system to ensure that this kind of incompatibility never arises, such as using package versioning: Requires: libguestfs >= 1.0.80 CALLS WITH OPTIONAL ARGUMENTS
A recent feature of the API is the introduction of calls which take optional arguments. In C these are declared 3 ways. The main way is as a call which takes variable arguments (ie. "..."), as in this example: int guestfs_add_drive_opts (guestfs_h *g, const char *filename, ...); Call this with a list of optional arguments, terminated by "-1". So to call with no optional arguments specified: guestfs_add_drive_opts (g, filename, -1); With a single optional argument: guestfs_add_drive_opts (g, filename, GUESTFS_ADD_DRIVE_OPTS_FORMAT, "qcow2", -1); With two: guestfs_add_drive_opts (g, filename, GUESTFS_ADD_DRIVE_OPTS_FORMAT, "qcow2", GUESTFS_ADD_DRIVE_OPTS_READONLY, 1, -1); and so forth. Don't forget the terminating "-1" otherwise Bad Things will happen! USING va_list FOR OPTIONAL ARGUMENTS The second variant has the same name with the suffix "_va", which works the same way but takes a "va_list". See the C manual for details. For the example function, this is declared: int guestfs_add_drive_opts_va (guestfs_h *g, const char *filename, va_list args); CONSTRUCTING OPTIONAL ARGUMENTS The third variant is useful where you need to construct these calls. You pass in a structure where you fill in the optional fields. The structure has a bitmask as the first element which you must set to indicate which fields you have filled in. For our example function the structure and call are declared: struct guestfs_add_drive_opts_argv { uint64_t bitmask; int readonly; const char *format; /* ... */ }; int guestfs_add_drive_opts_argv (guestfs_h *g, const char *filename, const struct guestfs_add_drive_opts_argv *optargs); You could call it like this: struct guestfs_add_drive_opts_argv optargs = { .bitmask = GUESTFS_ADD_DRIVE_OPTS_READONLY_BITMASK | GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK, .readonly = 1, .format = "qcow2" }; guestfs_add_drive_opts_argv (g, filename, &optargs); Notes: o The "_BITMASK" suffix on each option name when specifying the bitmask. o You do not need to fill in all fields of the structure. o There must be a one-to-one correspondence between fields of the structure that are filled in, and bits set in the bitmask. OPTIONAL ARGUMENTS IN OTHER LANGUAGES In other languages, optional arguments are expressed in the way that is natural for that language. We refer you to the language-specific documentation for more details on that. For guestfish, see "OPTIONAL ARGUMENTS" in guestfish(1). SETTING CALLBACKS TO HANDLE EVENTS Note: This section documents the generic event mechanism introduced in libguestfs 1.10, which you should use in new code if possible. The old functions "guestfs_set_log_message_callback", "guestfs_set_subprocess_quit_callback", "guestfs_set_launch_done_callback", "guestfs_set_close_callback" and "guestfs_set_progress_callback" are no longer documented in this manual page. Because of the ABI guarantee, the old functions continue to work. Handles generate events when certain things happen, such as log messages being generated, progress messages during long-running operations, or the handle being closed. The API calls described below let you register a callback to be called when events happen. You can register multiple callbacks (for the same, different or overlapping sets of events), and individually remove callbacks. If callbacks are not removed, then they remain in force until the handle is closed. In the current implementation, events are only generated synchronously: that means that events (and hence callbacks) can only happen while you are in the middle of making another libguestfs call. The callback is called in the same thread. Events may contain a payload, usually nothing (void), an array of 64 bit unsigned integers, or a message buffer. Payloads are discussed later on. CLASSES OF EVENTS GUESTFS_EVENT_CLOSE (payload type: void) The callback function will be called while the handle is being closed (synchronously from "guestfs_close"). Note that libguestfs installs an atexit(3) handler to try to clean up handles that are open when the program exits. This means that this callback might be called indirectly from exit(3), which can cause unexpected problems in higher-level languages (eg. if your HLL interpreter has already been cleaned up by the time this is called, and if your callback then jumps into some HLL function). If no callback is registered: the handle is closed without any callback being invoked. GUESTFS_EVENT_SUBPROCESS_QUIT (payload type: void) The callback function will be called when the child process quits, either asynchronously or if killed by "guestfs_kill_subprocess". (This corresponds to a transition from any state to the CONFIG state). If no callback is registered: the event is ignored. GUESTFS_EVENT_LAUNCH_DONE (payload type: void) The callback function will be called when the child process becomes ready first time after it has been launched. (This corresponds to a transition from LAUNCHING to the READY state). If no callback is registered: the event is ignored. GUESTFS_EVENT_PROGRESS (payload type: array of 4 x uint64_t) Some long-running operations can generate progress messages. If this callback is registered, then it will be called each time a progress message is generated (usually two seconds after the operation started, and three times per second thereafter until it completes, although the frequency may change in future versions). The callback receives in the payload four unsigned 64 bit numbers which are (in order): "proc_nr", "serial", "position", "total". The units of "total" are not defined, although for some operations "total" may relate in some way to the amount of data to be transferred (eg. in bytes or megabytes), and "position" may be the portion which has been transferred. The only defined and stable parts of the API are: o The callback can display to the user some type of progress bar or indicator which shows the ratio of "position":"total". o 0 <= "position" <= "total" o If any progress notification is sent during a call, then a final progress notification is always sent when "position" = "total" (unless the call fails with an error). This is to simplify caller code, so callers can easily set the progress indicator to "100%" at the end of the operation, without requiring special code to detect this case. o For some calls we are unable to estimate the progress of the call, but we can still generate progress messages to indicate activity. This is known as "pulse mode", and is directly supported by certain progress bar implementations (eg. GtkProgressBar). For these calls, zero or more progress messages are generated with "position = 0" and "total = 1", followed by a final message with "position = total = 1". As noted above, if the call fails with an error then the final message may not be generated. The callback also receives the procedure number ("proc_nr") and serial number ("serial") of the call. These are only useful for debugging protocol issues, and the callback can normally ignore them. The callback may want to print these numbers in error messages or debugging messages. If no callback is registered: progress messages are discarded. GUESTFS_EVENT_APPLIANCE (payload type: message buffer) The callback function is called whenever a log message is generated by qemu, the appliance kernel, guestfsd (daemon), or utility programs. If the verbose flag ("guestfs_set_verbose") is set before launch ("guestfs_launch") then additional debug messages are generated. If no callback is registered: the messages are discarded unless the verbose flag is set in which case they are sent to stderr. You can override the printing of verbose messages to stderr by setting up a callback. GUESTFS_EVENT_LIBRARY (payload type: message buffer) The callback function is called whenever a log message is generated by the library part of libguestfs. If the verbose flag ("guestfs_set_verbose") is set then additional debug messages are generated. If no callback is registered: the messages are discarded unless the verbose flag is set in which case they are sent to stderr. You can override the printing of verbose messages to stderr by setting up a callback. GUESTFS_EVENT_TRACE (payload type: message buffer) The callback function is called whenever a trace message is generated. This only applies if the trace flag ("guestfs_set_trace") is set. If no callback is registered: the messages are sent to stderr. You can override the printing of trace messages to stderr by setting up a callback. GUESTFS_EVENT_ENTER (payload type: function name) The callback function is called whenever a libguestfs function is entered. The payload is a string which contains the name of the function that we are entering (not including "guestfs_" prefix). Note that libguestfs functions can call themselves, so you may see many events from a single call. A few libguestfs functions do not generate this event. If no callback is registered: the event is ignored. guestfs_set_event_callback int guestfs_set_event_callback (guestfs_h *g, guestfs_event_callback cb, uint64_t event_bitmask, int flags, void *opaque); This function registers a callback ("cb") for all event classes in the "event_bitmask". For example, to register for all log message events, you could call this function with the bitmask "GUESTFS_EVENT_APPLIANCE|GUESTFS_EVENT_LIBRARY". To register a single callback for all possible classes of events, use "GUESTFS_EVENT_ALL". "flags" should always be passed as 0. "opaque" is an opaque pointer which is passed to the callback. You can use it for any purpose. The return value is the event handle (an integer) which you can use to delete the callback (see below). If there is an error, this function returns "-1", and sets the error in the handle in the usual way (see "guestfs_last_error" etc.) Callbacks remain in effect until they are deleted, or until the handle is closed. In the case where multiple callbacks are registered for a particular event class, all of the callbacks are called. The order in which multiple callbacks are called is not defined. guestfs_delete_event_callback void guestfs_delete_event_callback (guestfs_h *g, int event_handle); Delete a callback that was previously registered. "event_handle" should be the integer that was returned by a previous call to "guestfs_set_event_callback" on the same handle. guestfs_event_callback typedef void (*guestfs_event_callback) ( guestfs_h *g, void *opaque, uint64_t event, int event_handle, int flags, const char *buf, size_t buf_len, const uint64_t *array, size_t array_len); This is the type of the event callback function that you have to provide. The basic parameters are: the handle ("g"), the opaque user pointer ("opaque"), the event class (eg. "GUESTFS_EVENT_PROGRESS"), the event handle, and "flags" which in the current API you should ignore. The remaining parameters contain the event payload (if any). Each event may contain a payload, which usually relates to the event class, but for future proofing your code should be written to handle any payload for any event class. "buf" and "buf_len" contain a message buffer (if "buf_len == 0", then there is no message buffer). Note that this message buffer can contain arbitrary 8 bit data, including NUL bytes. "array" and "array_len" is an array of 64 bit unsigned integers. At the moment this is only used for progress messages. EXAMPLE: CAPTURING LOG MESSAGES One motivation for the generic event API was to allow GUI programs to capture debug and other messages. In libguestfs <= 1.8 these were sent unconditionally to "stderr". Events associated with log messages are: "GUESTFS_EVENT_LIBRARY", "GUESTFS_EVENT_APPLIANCE" and "GUESTFS_EVENT_TRACE". (Note that error messages are not events; you must capture error messages separately). Programs have to set up a callback to capture the classes of events of interest: int eh = guestfs_set_event_callback (g, message_callback, GUESTFS_EVENT_LIBRARY|GUESTFS_EVENT_APPLIANCE| GUESTFS_EVENT_TRACE, 0, NULL) == -1) if (eh == -1) { // handle error in the usual way } The callback can then direct messages to the appropriate place. In this example, messages are directed to syslog: static void message_callback ( guestfs_h *g, void *opaque, uint64_t event, int event_handle, int flags, const char *buf, size_t buf_len, const uint64_t *array, size_t array_len) { const int priority = LOG_USER|LOG_INFO; if (buf_len > 0) syslog (priority, "event 0x%lx: %s", event, buf); } CANCELLING LONG TRANSFERS
Some operations can be cancelled by the caller while they are in progress. Currently only operations that involve uploading or downloading data can be cancelled (technically: operations that have "FileIn" or "FileOut" parameters in the generator). guestfs_user_cancel void guestfs_user_cancel (guestfs_h *g); "guestfs_user_cancel" cancels the current upload or download operation. Unlike most other libguestfs calls, this function is signal safe and thread safe. You can call it from a signal handler or from another thread, without needing to do any locking. The transfer that was in progress (if there is one) will stop shortly afterwards, and will return an error. The errno (see "guestfs_last_errno") is set to "EINTR", so you can test for this to find out if the operation was cancelled or failed because of another error. No cleanup is performed: for example, if a file was being uploaded then after cancellation there may be a partially uploaded file. It is the caller's responsibility to clean up if necessary. There are two common places that you might call "guestfs_user_cancel". In an interactive text-based program, you might call it from a "SIGINT" signal handler so that pressing "^C" cancels the current operation. (You also need to call "guestfs_set_pgroup" so that child processes don't receive the "^C" signal). In a graphical program, when the main thread is displaying a progress bar with a cancel button, wire up the cancel button to call this function. PRIVATE DATA AREA
You can attach named pieces of private data to the libguestfs handle, fetch them by name, and walk over them, for the lifetime of the handle. This is called the private data area and is only available from the C API. To attach a named piece of data, use the following call: void guestfs_set_private (guestfs_h *g, const char *key, void *data); "key" is the name to associate with this data, and "data" is an arbitrary pointer (which can be "NULL"). Any previous item with the same key is overwritten. You can use any "key" you want, but your key should not start with an underscore character. Keys beginning with an underscore character are reserved for internal libguestfs purposes (eg. for implementing language bindings). It is recommended that you prefix the key with some unique string to avoid collisions with other users. To retrieve the pointer, use: void *guestfs_get_private (guestfs_h *g, const char *key); This function returns "NULL" if either no data is found associated with "key", or if the user previously set the "key"'s "data" pointer to "NULL". Libguestfs does not try to look at or interpret the "data" pointer in any way. As far as libguestfs is concerned, it need not be a valid pointer at all. In particular, libguestfs does not try to free the data when the handle is closed. If the data must be freed, then the caller must either free it before calling "guestfs_close" or must set up a close callback to do it (see "GUESTFS_EVENT_CLOSE"). To walk over all entries, use these two functions: void *guestfs_first_private (guestfs_h *g, const char **key_rtn); void *guestfs_next_private (guestfs_h *g, const char **key_rtn); "guestfs_first_private" returns the first key, pointer pair ("first" does not have any particular meaning -- keys are not returned in any defined order). A pointer to the key is returned in *key_rtn and the corresponding data pointer is returned from the function. "NULL" is returned if there are no keys stored in the handle. "guestfs_next_private" returns the next key, pointer pair. The return value of this function is also "NULL" is there are no further entries to return. Notes about walking over entries: o You must not call "guestfs_set_private" while walking over the entries. o The handle maintains an internal iterator which is reset when you call "guestfs_first_private". This internal iterator is invalidated when you call "guestfs_set_private". o If you have set the data pointer associated with a key to "NULL", ie: guestfs_set_private (g, key, NULL); then that "key" is not returned when walking. o *key_rtn is only valid until the next call to "guestfs_first_private", "guestfs_next_private" or "guestfs_set_private". The following example code shows how to print all keys and data pointers that are associated with the handle "g": const char *key; void *data = guestfs_first_private (g, &key); while (data != NULL) { printf ("key = %s, data = %p ", key, data); data = guestfs_next_private (g, &key); } More commonly you are only interested in keys that begin with an application-specific prefix "foo_". Modify the loop like so: const char *key; void *data = guestfs_first_private (g, &key); while (data != NULL) { if (strncmp (key, "foo_", strlen ("foo_")) == 0) printf ("key = %s, data = %p ", key, data); data = guestfs_next_private (g, &key); } If you need to modify keys while walking, then you have to jump back to the beginning of the loop. For example, to delete all keys prefixed with "foo_": const char *key; void *data; again: data = guestfs_first_private (g, &key); while (data != NULL) { if (strncmp (key, "foo_", strlen ("foo_")) == 0) { guestfs_set_private (g, key, NULL); /* note that 'key' pointer is now invalid, and so is the internal iterator */ goto again; } data = guestfs_next_private (g, &key); } Note that the above loop is guaranteed to terminate because the keys are being deleted, but other manipulations of keys within the loop might not terminate unless you also maintain an indication of which keys have been visited. SYSTEMTAP
The libguestfs C library can be probed using systemtap or DTrace. This is true of any library, not just libguestfs. However libguestfs also contains static markers to help in probing internal operations. You can list all the static markers by doing: stap -l 'process("/usr/lib*/libguestfs.so.0") .provider("guestfs").mark("*")' Note: These static markers are not part of the stable API and may change in future versions. SYSTEMTAP SCRIPT EXAMPLE This script contains examples of displaying both the static markers and some ordinary C entry points: global last; function display_time () { now = gettimeofday_us (); delta = 0; if (last > 0) delta = now - last; last = now; printf ("%d (+%d):", now, delta); } probe begin { last = 0; printf ("ready "); } /* Display all calls to static markers. */ probe process("/usr/lib*/libguestfs.so.0") .provider("guestfs").mark("*") ? { display_time(); printf (" %s %s ", $$name, $$parms); } /* Display all calls to guestfs_mkfs* functions. */ probe process("/usr/lib*/libguestfs.so.0") .function("guestfs_mkfs*") ? { display_time(); printf (" %s %s ", probefunc(), $$parms); } The script above can be saved to "test.stap" and run using the stap(1) program. Note that you either have to be root, or you have to add yourself to several special stap groups. Consult the systemtap documentation for more information. # stap /tmp/test.stap ready In another terminal, run a guestfish command such as this: guestfish -N fs In the first terminal, stap trace output similar to this is shown: 1318248056692655 (+0): launch_start 1318248056692850 (+195): launch_build_appliance_start 1318248056818285 (+125435): launch_build_appliance_end 1318248056838059 (+19774): launch_run_qemu 1318248061071167 (+4233108): launch_end 1318248061280324 (+209157): guestfs_mkfs g=0x1024ab0 fstype=0x46116f device=0x1024e60 ARCHITECTURE
Internally, libguestfs is implemented by running an appliance (a special type of small virtual machine) using qemu(1). Qemu runs as a child process of the main program. ___________________ / | main program | | | | | child process / appliance | | __________________________ | | / qemu +-------------------+ RPC | +-----------------+ | | libguestfs <--------------------> guestfsd | | | | | +-----------------+ | \___________________/ | | Linux kernel | | | +--^--------------+ | \_________|________________/ | _______v______ / | Device or | | disk image | \______________/ The library, linked to the main program, creates the child process and hence the appliance in the "guestfs_launch" function. Inside the appliance is a Linux kernel and a complete stack of userspace tools (such as LVM and ext2 programs) and a small controlling daemon called "guestfsd". The library talks to "guestfsd" using remote procedure calls (RPC). There is a mostly one-to-one correspondence between libguestfs API calls and RPC calls to the daemon. Lastly the disk image(s) are attached to the qemu process which translates device access by the appliance's Linux kernel into accesses to the image. A common misunderstanding is that the appliance "is" the virtual machine. Although the disk image you are attached to might also be used by some virtual machine, libguestfs doesn't know or care about this. (But you will care if both libguestfs's qemu process and your virtual machine are trying to update the disk image at the same time, since these usually results in massive disk corruption). STATE MACHINE
libguestfs uses a state machine to model the child process: | guestfs_create | | ____V_____ / | CONFIG | \__________/ ^ ^ | guestfs_launch | _\__V______ | / | | LAUNCHING | | \___________/ | / | guestfs_launch | / __|____V / | READY | \________/ The normal transitions are (1) CONFIG (when the handle is created, but there is no child process), (2) LAUNCHING (when the child process is booting up), (3) READY meaning the appliance is up, actions can be issued to, and carried out by, the child process. The guest may be killed by "guestfs_kill_subprocess", or may die asynchronously at any time (eg. due to some internal error), and that causes the state to transition back to CONFIG. Configuration commands for qemu such as "guestfs_add_drive" can only be issued when in the CONFIG state. The API offers one call that goes from CONFIG through LAUNCHING to READY. "guestfs_launch" blocks until the child process is READY to accept commands (or until some failure or timeout). "guestfs_launch" internally moves the state from CONFIG to LAUNCHING while it is running. API actions such as "guestfs_mount" can only be issued when in the READY state. These API calls block waiting for the command to be carried out. There are no non-blocking versions, and no way to issue more than one command per handle at the same time. Finally, the child process sends asynchronous messages back to the main program, such as kernel log messages. You can register a callback to receive these messages. INTERNALS
APPLIANCE BOOT PROCESS This process has evolved and continues to evolve. The description here corresponds only to the current version of libguestfs and is provided for information only. In order to follow the stages involved below, enable libguestfs debugging (set the environment variable "LIBGUESTFS_DEBUG=1"). Create the appliance "febootstrap-supermin-helper" is invoked to create the kernel, a small initrd and the appliance. The appliance is cached in "/var/tmp/.guestfs-<UID>" (or in another directory if "TMPDIR" is set). For a complete description of how the appliance is created and cached, read the febootstrap(8) and febootstrap-supermin-helper(8) man pages. Start qemu and boot the kernel qemu is invoked to boot the kernel. Run the initrd "febootstrap-supermin-helper" builds a small initrd. The initrd is not the appliance. The purpose of the initrd is to load enough kernel modules in order that the appliance itself can be mounted and started. The initrd is a cpio archive called "/var/tmp/.guestfs-<UID>/initrd". When the initrd has started you will see messages showing that kernel modules are being loaded, similar to this: febootstrap: ext2 mini initrd starting up febootstrap: mounting /sys febootstrap: internal insmod libcrc32c.ko febootstrap: internal insmod crc32c-intel.ko Find and mount the appliance device The appliance is a sparse file containing an ext2 filesystem which contains a familiar (although reduced in size) Linux operating system. It would normally be called "/var/tmp/.guestfs-<UID>/root". The regular disks being inspected by libguestfs are the first devices exposed by qemu (eg. as "/dev/vda"). The last disk added to qemu is the appliance itself (eg. "/dev/vdb" if there was only one regular disk). Thus the final job of the initrd is to locate the appliance disk, mount it, and switch root into the appliance, and run "/init" from the appliance. If this works successfully you will see messages such as: febootstrap: picked /sys/block/vdb/dev as root device febootstrap: creating /dev/root as block special 252:16 febootstrap: mounting new root on /root febootstrap: chroot Starting /init script ... Note that "Starting /init script ..." indicates that the appliance's init script is now running. Initialize the appliance The appliance itself now initializes itself. This involves starting certain processes like "udev", possibly printing some debug information, and finally running the daemon ("guestfsd"). The daemon Finally the daemon ("guestfsd") runs inside the appliance. If it runs you should see: verbose daemon enabled The daemon expects to see a named virtio-serial port exposed by qemu and connected on the other end to the library. The daemon connects to this port (and hence to the library) and sends a four byte message "GUESTFS_LAUNCH_FLAG", which initiates the communication protocol (see below). COMMUNICATION PROTOCOL Don't rely on using this protocol directly. This section documents how it currently works, but it may change at any time. The protocol used to talk between the library and the daemon running inside the qemu virtual machine is a simple RPC mechanism built on top of XDR (RFC 1014, RFC 1832, RFC 4506). The detailed format of structures is in "src/guestfs_protocol.x" (note: this file is automatically generated). There are two broad cases, ordinary functions that don't have any "FileIn" and "FileOut" parameters, which are handled with very simple request/reply messages. Then there are functions that have any "FileIn" or "FileOut" parameters, which use the same request and reply messages, but they may also be followed by files sent using a chunked encoding. ORDINARY FUNCTIONS (NO FILEIN/FILEOUT PARAMS) For ordinary functions, the request message is: total length (header + arguments, but not including the length word itself) struct guestfs_message_header (encoded as XDR) struct guestfs_<foo>_args (encoded as XDR) The total length field allows the daemon to allocate a fixed size buffer into which it slurps the rest of the message. As a result, the total length is limited to "GUESTFS_MESSAGE_MAX" bytes (currently 4MB), which means the effective size of any request is limited to somewhere under this size. Note also that many functions don't take any arguments, in which case the "guestfs_foo_args" is completely omitted. The header contains the procedure number ("guestfs_proc") which is how the receiver knows what type of args structure to expect, or none at all. For functions that take optional arguments, the optional arguments are encoded in the "guestfs_foo_args" structure in the same way as ordinary arguments. A bitmask in the header indicates which optional arguments are meaningful. The bitmask is also checked to see if it contains bits set which the daemon does not know about (eg. if more optional arguments were added in a later version of the library), and this causes the call to be rejected. The reply message for ordinary functions is: total length (header + ret, but not including the length word itself) struct guestfs_message_header (encoded as XDR) struct guestfs_<foo>_ret (encoded as XDR) As above the "guestfs_foo_ret" structure may be completely omitted for functions that return no formal return values. As above the total length of the reply is limited to "GUESTFS_MESSAGE_MAX". In the case of an error, a flag is set in the header, and the reply message is slightly changed: total length (header + error, but not including the length word itself) struct guestfs_message_header (encoded as XDR) struct guestfs_message_error (encoded as XDR) The "guestfs_message_error" structure contains the error message as a string. FUNCTIONS THAT HAVE FILEIN PARAMETERS A "FileIn" parameter indicates that we transfer a file into the guest. The normal request message is sent (see above). However this is followed by a sequence of file chunks. total length (header + arguments, but not including the length word itself, and not including the chunks) struct guestfs_message_header (encoded as XDR) struct guestfs_<foo>_args (encoded as XDR) sequence of chunks for FileIn param #0 sequence of chunks for FileIn param #1 etc. The "sequence of chunks" is: length of chunk (not including length word itself) struct guestfs_chunk (encoded as XDR) length of chunk struct guestfs_chunk (encoded as XDR) ... length of chunk struct guestfs_chunk (with data.data_len == 0) The final chunk has the "data_len" field set to zero. Additionally a flag is set in the final chunk to indicate either successful completion or early cancellation. At time of writing there are no functions that have more than one FileIn parameter. However this is (theoretically) supported, by sending the sequence of chunks for each FileIn parameter one after another (from left to right). Both the library (sender) and the daemon (receiver) may cancel the transfer. The library does this by sending a chunk with a special flag set to indicate cancellation. When the daemon sees this, it cancels the whole RPC, does not send any reply, and goes back to reading the next request. The daemon may also cancel. It does this by writing a special word "GUESTFS_CANCEL_FLAG" to the socket. The library listens for this during the transfer, and if it gets it, it will cancel the transfer (it sends a cancel chunk). The special word is chosen so that even if cancellation happens right at the end of the transfer (after the library has finished writing and has started listening for the reply), the "spurious" cancel flag will not be confused with the reply message. This protocol allows the transfer of arbitrary sized files (no 32 bit limit), and also files where the size is not known in advance (eg. from pipes or sockets). However the chunks are rather small ("GUESTFS_MAX_CHUNK_SIZE"), so that neither the library nor the daemon need to keep much in memory. FUNCTIONS THAT HAVE FILEOUT PARAMETERS The protocol for FileOut parameters is exactly the same as for FileIn parameters, but with the roles of daemon and library reversed. total length (header + ret, but not including the length word itself, and not including the chunks) struct guestfs_message_header (encoded as XDR) struct guestfs_<foo>_ret (encoded as XDR) sequence of chunks for FileOut param #0 sequence of chunks for FileOut param #1 etc. INITIAL MESSAGE When the daemon launches it sends an initial word ("GUESTFS_LAUNCH_FLAG") which indicates that the guest and daemon is alive. This is what "guestfs_launch" waits for. PROGRESS NOTIFICATION MESSAGES The daemon may send progress notification messages at any time. These are distinguished by the normal length word being replaced by "GUESTFS_PROGRESS_FLAG", followed by a fixed size progress message. The library turns them into progress callbacks (see "GUESTFS_EVENT_PROGRESS") if there is a callback registered, or discards them if not. The daemon self-limits the frequency of progress messages it sends (see "daemon/proto.c:notify_progress"). Not all calls generate progress messages. LIBGUESTFS VERSION NUMBERS
Since April 2010, libguestfs has started to make separate development and stable releases, along with corresponding branches in our git repository. These separate releases can be identified by version number: even numbers for stable: 1.2.x, 1.4.x, ... .-------- odd numbers for development: 1.3.x, 1.5.x, ... | v 1 . 3 . 5 ^ ^ | | | `-------- sub-version | `------ always '1' because we don't change the ABI Thus "1.3.5" is the 5th update to the development branch "1.3". As time passes we cherry pick fixes from the development branch and backport those into the stable branch, the effect being that the stable branch should get more stable and less buggy over time. So the stable releases are ideal for people who don't need new features but would just like the software to work. Our criteria for backporting changes are: o Documentation changes which don't affect any code are backported unless the documentation refers to a future feature which is not in stable. o Bug fixes which are not controversial, fix obvious problems, and have been well tested are backported. o Simple rearrangements of code which shouldn't affect how it works get backported. This is so that the code in the two branches doesn't get too far out of step, allowing us to backport future fixes more easily. o We don't backport new features, new APIs, new tools etc, except in one exceptional case: the new feature is required in order to implement an important bug fix. A new stable branch starts when we think the new features in development are substantial and compelling enough over the current stable branch to warrant it. When that happens we create new stable and development versions 1.N.0 and 1.(N+1).0 [N is even]. The new dot-oh release won't necessarily be so stable at this point, but by backporting fixes from development, that branch will stabilize over time. EXTENDING LIBGUESTFS
ADDING A NEW API ACTION Large amounts of boilerplate code in libguestfs (RPC, bindings, documentation) are generated, and this makes it easy to extend the libguestfs API. To add a new API action there are two changes: 1. You need to add a description of the call (name, parameters, return type, tests, documentation) to "generator/generator_actions.ml". There are two sorts of API action, depending on whether the call goes through to the daemon in the appliance, or is serviced entirely by the library (see "ARCHITECTURE" above). "guestfs_sync" is an example of the former, since the sync is done in the appliance. "guestfs_set_trace" is an example of the latter, since a trace flag is maintained in the handle and all tracing is done on the library side. Most new actions are of the first type, and get added to the "daemon_functions" list. Each function has a unique procedure number used in the RPC protocol which is assigned to that action when we publish libguestfs and cannot be reused. Take the latest procedure number and increment it. For library-only actions of the second type, add to the "non_daemon_functions" list. Since these functions are serviced by the library and do not travel over the RPC mechanism to the daemon, these functions do not need a procedure number, and so the procedure number is set to "-1". 2. Implement the action (in C): For daemon actions, implement the function "do_<name>" in the "daemon/" directory. For library actions, implement the function "guestfs__<name>" (note: double underscore) in the "src/" directory. In either case, use another function as an example of what to do. After making these changes, use "make" to compile. Note that you don't need to implement the RPC, language bindings, manual pages or anything else. It's all automatically generated from the OCaml description. ADDING TESTS FOR AN API ACTION You can supply zero or as many tests as you want per API call. The tests can either be added as part of the API description ("generator/generator_actions.ml"), or in some rarer cases you may want to drop a script into "tests/*/". Note that adding a script to "tests/*/" is slower, so if possible use the first method. The following describes the test environment used when you add an API test in "generator_actions.ml". The test environment has 4 block devices: "/dev/sda" 500MB General block device for testing. "/dev/sdb" 50MB "/dev/sdb1" is an ext2 filesystem used for testing filesystem write operations. "/dev/sdc" 10MB Used in a few tests where two block devices are needed. "/dev/sdd" ISO with fixed content (see "images/test.iso"). To be able to run the tests in a reasonable amount of time, the libguestfs appliance and block devices are reused between tests. So don't try testing "guestfs_kill_subprocess" :-x Each test starts with an initial scenario, selected using one of the "Init*" expressions, described in "generator/generator_types.ml". These initialize the disks mentioned above in a particular way as documented in "generator_types.ml". You should not assume anything about the previous contents of other disks that are not initialized. You can add a prerequisite clause to any individual test. This is a run-time check, which, if it fails, causes the test to be skipped. Useful if testing a command which might not work on all variations of libguestfs builds. A test that has prerequisite of "Always" means to run unconditionally. In addition, packagers can skip individual tests by setting environment variables before running "make check". SKIP_TEST_<CMD>_<NUM>=1 eg: "SKIP_TEST_COMMAND_3=1" skips test #3 of "guestfs_command". or: SKIP_TEST_<CMD>=1 eg: "SKIP_TEST_ZEROFREE=1" skips all "guestfs_zerofree" tests. Packagers can run only certain tests by setting for example: TEST_ONLY="vfs_type zerofree" See "tests/c-api/tests.c" for more details of how these environment variables work. DEBUGGING NEW API ACTIONS Test new actions work before submitting them. You can use guestfish to try out new commands. Debugging the daemon is a problem because it runs inside a minimal environment. However you can fprintf messages in the daemon to stderr, and they will show up if you use "guestfish -v". FORMATTING CODE AND OTHER CONVENTIONS Our C source code generally adheres to some basic code-formatting conventions. The existing code base is not totally consistent on this front, but we do prefer that contributed code be formatted similarly. In short, use spaces-not-TABs for indentation, use 2 spaces for each indentation level, and other than that, follow the K&R style. If you use Emacs, add the following to one of one of your start-up files (e.g., ~/.emacs), to help ensure that you get indentation right: ;;; In libguestfs, indent with spaces everywhere (not TABs). ;;; Exceptions: Makefile and ChangeLog modes. (add-hook 'find-file-hook '(lambda () (if (and buffer-file-name (string-match "/libguestfs\>" (buffer-file-name)) (not (string-equal mode-name "Change Log")) (not (string-equal mode-name "Makefile"))) (setq indent-tabs-mode nil)))) ;;; When editing C sources in libguestfs, use this style. (defun libguestfs-c-mode () "C mode with adjusted defaults for use with libguestfs." (interactive) (c-set-style "K&R") (setq c-indent-level 2) (setq c-basic-offset 2)) (add-hook 'c-mode-hook '(lambda () (if (string-match "/libguestfs\>" (buffer-file-name)) (libguestfs-c-mode)))) Enable warnings when compiling (and fix any problems this finds): ./configure --enable-gcc-warnings Useful targets are: make syntax-check # checks the syntax of the C code make check # runs the test suite DAEMON CUSTOM PRINTF FORMATTERS In the daemon code we have created custom printf formatters %Q and %R, which are used to do shell quoting. %Q Simple shell quoted string. Any spaces or other shell characters are escaped for you. %R Same as %Q except the string is treated as a path which is prefixed by the sysroot. For example: asprintf (&cmd, "cat %R", path); would produce "cat /sysroot/some path with spaces" Note: Do not use these when you are passing parameters to the "command{,r,v,rv}()" functions. These parameters do NOT need to be quoted because they are not passed via the shell (instead, straight to exec). You probably want to use the "sysroot_path()" function however. SUBMITTING YOUR NEW API ACTIONS Submit patches to the mailing list: <http://www.redhat.com/mailman/listinfo/libguestfs> and CC to rjones@redhat.com. INTERNATIONALIZATION (I18N) SUPPORT We support i18n (gettext anyhow) in the library. However many messages come from the daemon, and we don't translate those at the moment. One reason is that the appliance generally has all locale files removed from it, because they take up a lot of space. So we'd have to readd some of those, as well as copying our PO files into the appliance. Debugging messages are never translated, since they are intended for the programmers. SOURCE CODE SUBDIRECTORIES "align" virt-alignment-scan(1) command and documentation. "appliance" The libguestfs appliance, build scripts and so on. "cat" The virt-cat(1), virt-filesystems(1) and virt-ls(1) commands and documentation. "contrib" Outside contributions, experimental parts. "daemon" The daemon that runs inside the libguestfs appliance and carries out actions. "df" virt-df(1) command and documentation. "edit" virt-edit(1) command and documentation. "examples" C API example code. "fish" guestfish(1), the command-line shell, and various shell scripts built on top such as virt-copy-in(1), virt-copy-out(1), virt-tar-in(1), virt-tar-out(1). "format" virt-format(1) command and documentation. "fuse" guestmount(1), FUSE (userspace filesystem) built on top of libguestfs. "generator" The crucially important generator, used to automatically generate large amounts of boilerplate C code for things like RPC and bindings. "inspector" virt-inspector(1), the virtual machine image inspector. "logo" Logo used on the website. The fish is called Arthur by the way. "m4" M4 macros used by autoconf. "po" Translations of simple gettext strings. "po-docs" The build infrastructure and PO files for translations of manpages and POD files. Eventually this will be combined with the "po" directory, but that is rather complicated. "rescue" virt-rescue(1) command and documentation. "resize" virt-resize(1) command and documentation. "sparsify" virt-sparsify(1) command and documentation. "src" Source code to the C library. "sysprep" virt-sysprep(1) command and documentation. "test-tool" Test tool for end users to test if their qemu/kernel combination will work with libguestfs. "tests" Tests. "tools" Command line tools written in Perl (virt-win-reg(1) and many others). "csharp" "erlang" "gobject" "haskell" "java" "ocaml" "php" "perl" "python" "ruby" Language bindings. MAKING A STABLE RELEASE When we make a stable release, there are several steps documented here. See "LIBGUESTFS VERSION NUMBERS" for general information about the stable branch policy. o Check "make && make check" works on at least Fedora, Debian and Ubuntu. o Finalize RELEASE-NOTES. o Update ROADMAP. o Run "src/api-support/update-from-tarballs.sh". o Push and pull from Transifex. Run: tx push -s to push the latest POT files to Transifex. Then run: ./tx-pull.sh which is a wrapper to pull the latest translated "*.po" files. o Create new stable and development directories under <http://libguestfs.org/download>. o Create the branch in git: git tag -a 1.XX.0 -m "Version 1.XX.0 (stable)" git tag -a 1.YY.0 -m "Version 1.YY.0 (development)" git branch stable-1.XX git push origin tag 1.XX.0 1.YY.0 stable-1.XX LIMITS
PROTOCOL LIMITS Internally libguestfs uses a message-based protocol to pass API calls and their responses to and from a small "appliance" (see "INTERNALS" for plenty more detail about this). The maximum message size used by the protocol is slightly less than 4 MB. For some API calls you may need to be aware of this limit. The API calls which may be affected are individually documented, with a link back to this section of the documentation. A simple call such as "guestfs_cat" returns its result (the file data) in a simple string. Because this string is at some point internally encoded as a message, the maximum size that it can return is slightly under 4 MB. If the requested file is larger than this then you will get an error. In order to transfer large files into and out of the guest filesystem, you need to use particular calls that support this. The sections "UPLOADING" and "DOWNLOADING" document how to do this. You might also consider mounting the disk image using our FUSE filesystem support (guestmount(1)). MAXIMUM NUMBER OF DISKS When using virtio disks (the default) the current limit is 25 disks. Virtio itself consumes 1 virtual PCI slot per disk, and PCI is limited to 31 slots. However febootstrap only understands disks with names "/dev/vda" through "/dev/vdz" (26 letters) and it reserves one disk for its own purposes. We are working to substantially raise this limit in future versions but it requires complex changes to qemu. In future versions of libguestfs it should also be possible to "hot plug" disks (add and remove disks after calling "guestfs_launch"). This also requires changes to qemu. MAXIMUM NUMBER OF PARTITIONS PER DISK Virtio limits the maximum number of partitions per disk to 15. This is because it reserves 4 bits for the minor device number (thus "/dev/vda", and "/dev/vda1" through "/dev/vda15"). If you attach a disk with more than 15 partitions, the extra partitions are ignored by libguestfs. MAXIMUM SIZE OF A DISK Probably the limit is between 2**63-1 and 2**64-1 bytes. We have tested block devices up to 1 exabyte (2**60 or 1,152,921,504,606,846,976 bytes) using sparse files backed by an XFS host filesystem. Although libguestfs probably does not impose any limit, the underlying host storage will. If you store disk images on a host ext4 filesystem, then the maximum size will be limited by the maximum ext4 file size (currently 16 TB). If you store disk images as host logical volumes then you are limited by the maximum size of an LV. For the hugest disk image files, we recommend using XFS on the host for storage. MAXIMUM SIZE OF A PARTITION The MBR (ie. classic MS-DOS) partitioning scheme uses 32 bit sector numbers. Assuming a 512 byte sector size, this means that MBR cannot address a partition located beyond 2 TB on the disk. It is recommended that you use GPT partitions on disks which are larger than this size. GPT uses 64 bit sector numbers and so can address partitions which are theoretically larger than the largest disk we could support. MAXIMUM SIZE OF A FILESYSTEM, FILES, DIRECTORIES This depends on the filesystem type. libguestfs itself does not impose any known limit. Consult Wikipedia or the filesystem documentation to find out what these limits are. MAXIMUM UPLOAD AND DOWNLOAD The API functions "guestfs_upload", "guestfs_download", "guestfs_tar_in", "guestfs_tar_out" and the like allow unlimited sized uploads and downloads. INSPECTION LIMITS The inspection code has several arbitrary limits on things like the size of Windows Registry hive it will read, and the length of product name. These are intended to stop a malicious guest from consuming arbitrary amounts of memory and disk space on the host, and should not be reached in practice. See the source code for more information. ENVIRONMENT VARIABLES
FEBOOTSTRAP_KERNEL FEBOOTSTRAP_MODULES These two environment variables allow the kernel that libguestfs uses in the appliance to be selected. If $FEBOOTSTRAP_KERNEL is not set, then the most recent host kernel is chosen. For more information about kernel selection, see febootstrap-supermin-helper(8). This feature is only available in febootstrap >= 3.8. LIBGUESTFS_APPEND Pass additional options to the guest kernel. LIBGUESTFS_DEBUG Set "LIBGUESTFS_DEBUG=1" to enable verbose messages. This has the same effect as calling "guestfs_set_verbose (g, 1)". LIBGUESTFS_MEMSIZE Set the memory allocated to the qemu process, in megabytes. For example: LIBGUESTFS_MEMSIZE=700 LIBGUESTFS_PATH Set the path that libguestfs uses to search for a supermin appliance. See the discussion of paths in section "PATH" above. LIBGUESTFS_QEMU Set the default qemu binary that libguestfs uses. If not set, then the qemu which was found at compile time by the configure script is used. See also "QEMU WRAPPERS" above. LIBGUESTFS_TRACE Set "LIBGUESTFS_TRACE=1" to enable command traces. This has the same effect as calling "guestfs_set_trace (g, 1)". TMPDIR Location of temporary directory, defaults to "/tmp" except for the cached supermin appliance which defaults to "/var/tmp". If libguestfs was compiled to use the supermin appliance then the real appliance is cached in this directory, shared between all handles belonging to the same EUID. You can use $TMPDIR to configure another directory to use in case "/var/tmp" is not large enough. SEE ALSO
guestfs-examples(3), guestfs-erlang(3), guestfs-java(3), guestfs-ocaml(3), guestfs-perl(3), guestfs-python(3), guestfs-ruby(3), guestfish(1), guestmount(1), virt-alignment-scan(1), virt-cat(1), virt-copy-in(1), virt-copy-out(1), virt-df(1), virt-edit(1), virt-filesystems(1), virt-format(1), virt-inspector(1), virt-list-filesystems(1), virt-list-partitions(1), virt-ls(1), virt-make-fs(1), virt-rescue(1), virt-resize(1), virt-sparsify(1), virt-sysprep(1), virt-tar(1), virt-tar-in(1), virt-tar-out(1), virt-win-reg(1), guestfs-faq(1), guestfs-performance(1), guestfs-testing(1), libguestfs-test-tool(1), libguestfs-make-fixed-appliance(1), febootstrap(1), febootstrap-supermin-helper(8), qemu(1), hivex(3), stap(1), <http://libguestfs.org/>. Tools with a similar purpose: fdisk(8), parted(8), kpartx(8), lvm(8), disktype(1). BUGS
To get a list of bugs against libguestfs use this link: <https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools> To report a new bug against libguestfs use this link: <https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools> When reporting a bug, please check: o That the bug hasn't been reported already. o That you are testing a recent version. o Describe the bug accurately, and give a way to reproduce it. o Run libguestfs-test-tool and paste the complete, unedited output into the bug report. AUTHORS
Richard W.M. Jones ("rjones at redhat dot com") COPYRIGHT
Copyright (C) 2009-2012 Red Hat Inc. <http://libguestfs.org/> This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA libguestfs-1.18.1 2013-12-07 guestfs(3)
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