mknod(2) mknod(2)
NAME
mknod - make a directory, or a special or ordinary file
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
int mknod(const char *path, mode_t mode, dev_t dev);
DESCRIPTION
mknod creates a new file named by the path name pointed to by
path. The file type and permissions of the new file are
initialized from mode.
The file type is specified in mode by the S_IFMT bits, which
must be set to one of the following values:
S_IFIFO fifo special
S_IFCHR character special
S_IFDIR directory
S_IFBLK block special
S_IFREG ordinary file
The file access permissions are specified in mode by the
0007777 bits, and may be constructed by an OR of the following
values:
S_ISUID 04000 Set user ID on execution.
S_ISGID 020#0 Set group ID on execution if # is 7, 5, 3, or 1
Enable mandatory file/record locking if # is 6, 4, 2, or 0
S_ISVTX 01000 Save text image after execution.
S_IRWXU 00700 Read, write, execute by owner.
S_IRUSR 00400 Read by owner.
S_IWUSR 00200 Write by owner.
S_IXUSR 00100 Execute (search if a directory) by owner.
S_IRWXG 00070 Read, write, execute by group.
S_IRGRP 00040 Read by group.
S_IWGRP 00020 Write by group.
S_IXGRP 00010 Execute by group.
S_IRWXO 00007 Read, write, execute (search) by others.
S_IROTH 00004 Read by others.
S_IWOTH 00002 Write by others
S_IXOTH 00001 Execute by others.
The owner ID of the file is set to the effective user ID of
the process. The group ID of the file is set to the effective
group ID of the process. However, if the S_ISGID bit is set
in the parent directory, then the group ID of the file is
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mknod(2) mknod(2)
inherited from the parent. If the group ID of the new file
does not match the effective group ID or one of the
supplementary group IDs, the S_ISGID bit is cleared.
The access permission bits of mode are modified by the
process's file mode creation mask: all bits set in the
process's file mode creation mask are cleared [see umask(2)].
If mode indicates a block or character special file, dev is a
configuration-dependent specification of a character or block
I/O device. If mode does not indicate a block special or
character special device, dev is ignored. See makedev(3C).
mknod checks to see if the driver has been installed and
whether or not it is an old-style driver. If the driver is
installed and it is an old-style driver, the minor number is
limited to 255. If it's not an old-style driver, then it must
be a new-style driver or uninstalled, and the minor number is
limited to the current value of the MAXMINOR tunable. Of
course, this tunable is set to 255 by default. If the range
check fails, mknod fails with EINVAL.
mknod may be invoked only by a privileged user for file types
other than FIFO special.
If path is a symbolic link, it is not followed.
Return Values
If mknod succeeds, it returns 0. If mknod fails, it returns
-1 and sets errno to identify the error.
Errors
mknod fails and creates no new file if one or more of the
following are true:
EEXIST The named file exists.
EINVAL dev is invalid.
EFAULT path points outside the allocated address space of the
process.
ELOOP Too many symbolic links were encountered in translating
path.
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mknod(2) mknod(2)
EMULTIHOP
Components of path require hopping to multiple remote
machines and the file system type does not allow it.
ENAMETOOLONG
The length of the path argument exceeds {PATH_MAX}, or
the length of a path component exceeds {NAME_MAX} while
_POSIX_NO_TRUNC is in effect.
ENOTDIR
A component of the path prefix is not a directory.
ENOENT A component of the path prefix does not exist or is a
null pathname.
EPERM The effective user ID of the process is not super-user.
EROFS The directory in which the file is to be created is
located on a read-only file system.
ENOSPC No space is available.
EINTR A signal was caught during the mknod system call.
ENOLINK
path points to a remote machine and the link to that
machine is no longer active.
REFERENCES
chmod(2), exec(2), makedev(3C), mkdir(1), mkfifo(3C), stat(5),
umask(2)
Copyright 1994 Novell, Inc. Page 3