CHOWN(2) OpenBSD Programmer's Manual CHOWN(2)NAME
chown, lchown, fchown - change owner and group of a file or link
SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
int
chown(const char *path, uid_t owner, gid_t group);
int
lchown(const char *path, uid_t owner, gid_t group);
int
fchown(int fd, uid_t owner, gid_t group);
DESCRIPTION
The owner ID and group ID of the file (or link) named by path or
referenced by fd is changed as specified by the arguments owner and
group. The owner of a file may change the group to a group of which he
or she is a member, but the change owner capability is restricted to the
superuser.
By default, chown() clears the set-user-ID and set-group-ID bits on the
file to prevent accidental or mischievous creation of set-user-ID and
set-group-ID programs. This behaviour can be overridden by setting the
sysctl(8) variable fs.posix.setuid to zero.
lchown() operates similarly to how chown() operated on older systems, and
does not follow symbolic links. It allows the owner and group of a
symbolic link to be set.
fchown() is particularly useful when used in conjunction with the file
locking primitives (see flock(2)).
One of the owner or group IDs may be left unchanged by specifying it as
-1.
RETURN VALUES
Zero is returned if the operation was successful; -1 is returned if an
error occurs, with a more specific error code being placed in the global
variable errno.
ERRORSchown() or lchown() will fail and the file or link will be unchanged if:
[ENOTDIR] A component of the path prefix is not a directory.
[ENAMETOOLONG]
A component of a pathname exceeded {NAME_MAX} characters,
or an entire path name exceeded {PATH_MAX} characters.
[ENOENT] The named file does not exist.
[EACCES] Search permission is denied for a component of the path
prefix.
[ELOOP] Too many symbolic links were encountered in translating the
pathname.
[EPERM] The effective user ID is not the superuser.
[EROFS] The named file resides on a read-only file system.
[EFAULT] path points outside the process's allocated address space.
[EIO] An I/O error occurred while reading from or writing to the
file system.
fchown() will fail if:
[EBADF] fd does not refer to a valid descriptor.
[EINVAL] fd refers to a socket, not a file.
[EPERM] The effective user ID is not the superuser.
[EROFS] The named file resides on a read-only file system.
[EIO] An I/O error occurred while reading from or writing to the
file system.
SEE ALSOchgrp(1), chmod(2), flock(2), chown(8)STANDARDS
The chown() function is expected to conform to IEEE Std 1003.1-1988
(``POSIX'').
HISTORY
The fchown() function call appeared in 4.2BSD.
The chown() and fchown() functions were changed to follow symbolic links
in 4.4BSD.
The lchown() function was added to OpenBSD due to the above.
OpenBSD 4.9 May 31, 2007 OpenBSD 4.9
