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RedHat 9 (Linux i386) - man page for mknod (redhat section 2)

MKNOD(2)			    Linux Programmer's Manual				 MKNOD(2)

       mknod - create a special or ordinary file

       #include <sys/types.h>
       #include <sys/stat.h>
       #include <fcntl.h>
       #include <unistd.h>

       int mknod(const char *pathname, mode_t mode, dev_t dev);

       mknod attempts to create a filesystem node (file, device special file or named pipe) named
       pathname, specified by mode and dev.

       mode specifies both the permissions to use and the type of node to be created.

       It should be a combination (using bitwise OR) of one of the file types  listed  below  and
       the permissions for the new node.

       The  permissions  are modified by the process's umask in the usual way: the permissions of
       the created node are (mode & ~umask).

       The file type should be one of S_IFREG, S_IFCHR, S_IFBLK and S_IFIFO to specify	a  normal
       file  (which  will  be  created empty), character special file, block special file or FIFO
       (named pipe), respectively, or zero, which will create a normal file.

       If the file type is S_IFCHR or S_IFBLK then dev specifies the major and minor  numbers  of
       the newly created device special file; otherwise it is ignored.

       If pathname already exists, or is a symlink, this call fails with an EEXIST error.

       The  newly  created node will be owned by the effective uid of the process.  If the direc-
       tory containing the node has the set group id bit set, or if  the  filesystem  is  mounted
       with  BSD  group  semantics, the new node will inherit the group ownership from its parent
       directory; otherwise it will be owned by the effective gid of the process.

       mknod returns zero on success, or -1 if an error occurred (in which  case,  errno  is  set

       EPERM  mode requested creation of something other than a FIFO (named pipe), and the caller
	      is not the superuser; also returned if the filesystem containing pathname does  not
	      support the type of node requested.

       EINVAL mode  requested creation of something other than a normal file, device special file
	      or FIFO.

       EEXIST pathname already exists.

       EFAULT pathname points outside your accessible address space.

       EACCES The parent directory does not allow write permission to the process, or one of  the
	      directories in pathname did not allow search (execute) permission.

	      pathname was too long.

       ENOENT A directory component in pathname does not exist or is a dangling symbolic link.

	      A component used as a directory in pathname is not, in fact, a directory.

       ENOMEM Insufficient kernel memory was available.

       EROFS  pathname refers to a file on a read-only filesystem.

       ELOOP  Too many symbolic links were encountered in resolving pathname.

       ENOSPC The device containing pathname has no room for the new node.

       SVr4  (but  the call requires privilege and is thus not in POSIX), 4.4BSD.  The Linux ver-
       sion differs from the SVr4 version in that it does not require root permission  to  create
       pipes, also in that no EMULTIHOP, ENOLINK, or EINTR error is documented.

       POSIX  1003.1-2001  says:  "The	only  portable use of mknod() is to create a FIFO-special
       file. If mode is not S_IFIFO or dev is not 0, the behavior of mknod() is unspecified."

       Under Linux, this call cannot be used to create directories or socket files, and cannot be
       used  to  create normal files by users other than the superuser.  One should make directo-
       ries with mkdir, and FIFOs with mkfifo.

       There are many infelicities in the protocol underlying NFS.  Some of these affect mknod.

       close(2), fcntl(2), mkdir(2), mount(2), open(2), read(2),  socket(2),  stat(2),	umask(2),
       unlink(2), write(2), fopen(3), mkfifo(3)

Linux 1.0				    1994-03-29					 MKNOD(2)

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