CHOWN(2) MachTen Programmer’s Manual CHOWN(2)

NAME
chown, fchown - change owner and group of a file

SYNOPSIS
#include <unistd.h>

int
chown(const char *path, uid_t owner, gid_t group)

int
fchown(int fd, uid_t owner, uid_t group)

DESCRIPTION
The owner ID and group ID of the file 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 super-user.

Chown() clears the set-user-id and set-group-id bits on the file to pre-
vent accidental or mischievous creation of set-user-id and set-group-id
programs.

Fchown() is particularly useful when used in conjunction with the file
locking primitives (see flock(2)).

One of the owner or group id’s 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.

ERRORS
Chown() will fail and the file will be unchanged if:

[ENOTDIR] A component of the path prefix is not a directory.

[EINVAL] The pathname contains a character with the high-order bit
set.

[ENAMETOOLONG]
A component of a pathname exceeded 255 characters, or an
entire path name exceeded 1023 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 super-user.

[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 super-user.

[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 ALSO
chown(8), chgrp(1), chmod(2), flock(2)

STANDARDS
Chown() 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.

4th Berkeley Distribution April 19, 1994 2