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Mac OS X / Darwin man pages : chown (2)
chown (2)

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Name

chown, 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
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.

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.

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 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 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

The chown() function is expected to conform to IEEE Std 1003.1-1988 (``POSIX.1'').

History

The fchown() function call appeared in 4.2BSD.

The chown() and fchown() functions were changed to follow symbolic links in 4.4BSD.

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