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getvfsbyname(3) [freebsd man page]

GETVFSBYNAME(3) 					   BSD Library Functions Manual 					   GETVFSBYNAME(3)

NAME
getvfsbyname -- get information about a file system LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <sys/param.h> #include <sys/mount.h> int getvfsbyname(const char *name, struct xvfsconf *vfc); DESCRIPTION
The getvfsbyname() function provides access to information about a file system module that is configured in the kernel. If successful, the requested file system xvfsconf is returned in the location pointed to by vfc. The fields in a ``struct xvfsconf'' are defined as follows: vfc_name the name of the file system vfc_typenum the file system type number assigned by the kernel vfc_refcount the number of active mount points using the file system vfc_flags flag bits, as described below The flags are defined as follows: VFCF_STATIC statically compiled into kernel VFCF_NETWORK may get data over the network VFCF_READONLY writes are not implemented VFCF_SYNTHETIC data does not represent real files VFCF_LOOPBACK aliases some other mounted FS VFCF_UNICODE stores file names as Unicode VFCF_JAIL can be mounted from within a jail if security.jail.mount_allowed sysctl is set to 1 VFCF_DELEGADMIN supports delegated administration if vfs.usermount sysctl is set to 1 RETURN VALUES
The getvfsbyname() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS
The following errors may be reported: [EFAULT] The vfc argument points to an invalid address. [ENOENT] The name argument specifies a file system that is unknown or not configured in the kernel. SEE ALSO
jail(2), mount(2), sysctl(3), jail(8), mount(8), sysctl(8) HISTORY
A variant of the getvfsbyname() function first appeared in FreeBSD 2.0. BSD
April 5, 2007 BSD

Check Out this Related Man Page

VFSCONF(9)						   BSD Kernel Developer's Manual						VFSCONF(9)

NAME
vfsconf -- vfs configuration information SYNOPSIS
#include <sys/param.h> #include <sys/mount.h> int vfs_register(struct vfsconf *vfc); int vfs_unregister(struct vfsconf *vfc); int vfs_modevent(module_t mod, int type, void *data); DESCRIPTION
Each file system type known to the kernel has a vfsconf structure that contains the information required to create a new mount of that file systems type. struct vfsconf { struct vfsops *vfc_vfsops; /* file system operations vector */ char vfc_name[MFSNAMELEN]; /* file system type name */ int vfc_typenum; /* historic file system type number */ int vfc_refcount; /* number mounted of this type */ int vfc_flags; /* permanent flags */ struct vfsconf *vfc_next; /* next in list */ }; When a new file system is mounted, mount(2) does a lookup of the vfsconf structure by its name, and if it is not already registered, attempts to load a kernel module for it. The file system operations for the new mount point are taken from vfc_vfsops, and mnt_vfc in the mount structure is made to point directly at the vfsconf structure for the file system type. The file system type number is taken from vfc_typenum which was assigned in vfs_register(), and the mount flags are taken from a mask of vfc_flags. Each time a file system of a given type is mounted, vfc_refcount is incremented. vfs_register() takes a new vfsconf structure and adds it to the list of existing file systems. If the type has not already been registered, it is initialized by calling the vfs_init() function in the file system operations vector. vfs_register() also updates the oid's of any sysctl nodes for this file system type to be the same as the newly assigned type number. vfs_unregister() unlinks vfc from the list of registered file system types if there are currently no mounted instances. If the vfs_uninit() function in the file systems initialization vector is defined, it is called. vfs_modevent() is registered by VFS_SET() to handle the loading and unloading of file system kernel modules. In the case of MOD_LOAD, vfs_register() is called. In the case of MOD_UNLOAD, vfs_unregister() is called. RETURN VALUES
vfs_register() returns 0 if successful; otherwise, EEXIST is returned indicating that the file system type has already been registered. vfs_unregister() returns 0 if successful. If no vfsconf entry can be found matching the name in vfc, EINVAL is returned. If the reference count of mounted instances of the file system type is not zero, EBUSY is returned. If vfs_uninit() is called, any errors it returns will be returned by vfs_unregister(). vfs_modevent() returns the result of the call to vfs_register() or vfs_unregister(), whatever the case. SEE ALSO
mount(2), vfs_rootmountalloc(9), VFS_SET(9) AUTHORS
This manual page was written by Chad David <davidc@acns.ab.ca>. BSD
June 16, 2013 BSD

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