CHOWN(2) MidnightBSD System Calls Manual CHOWN(2)

NAME

chown, fchown, lchown — change owner and group of a file

LIBRARY

Standard C Library (libc, −lc)

SYNOPSIS

#include <unistd.h>

int

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

int

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

int

lchown(const char *path, uid_t owner, gid_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.

The chown() system call 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 if not executed by the super-user. The chown() system call follows symbolic links to operate on the target of the link rather than the link itself.

The fchown() system call is particularly useful when used in conjunction with the file locking primitives (see flock(2)).

The lchown() system call is similar to chown() but does not follow symbolic links.

One of the owner or group id’s may be left unchanged by specifying it as -1.

RETURN VALUES

Upon successful completion, the value 0 is returned; otherwise the value −1 is returned and the global variable errno is set to indicate the error.

ERRORS

The chown() and lchown() will fail and the file will be unchanged if:

[ENOTDIR]

A component of the path prefix is not a directory.

[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 operation would change the ownership, but the effective user ID is not the super-user.

[EPERM]

The named file has its immutable or append-only flag set, see the chflags(2) manual page for more information.

[EROFS]

The named file resides on a read-only file system.

[EFAULT]

The path argument points outside the process’s allocated address space.

[EIO]

An I/O error occurred while reading from or writing to the file system.

The fchown() system call will fail if:

[EBADF]

The fd argument does not refer to a valid descriptor.

[EINVAL]

The fd argument 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

chgrp(1), chflags(2), chmod(2), flock(2), chown(8)

STANDARDS

The chown() system call is expected to conform to ISO/IEC 9945-1:1990 (‘‘POSIX.1’’).

HISTORY

The chown() function appeared in Version 7 AT&T UNIX. The fchown() system call appeared in 4.2BSD.

The chown() system call was changed to follow symbolic links in 4.4BSD. The lchown() system call was added in FreeBSD 3.0 to compensate for the loss of functionality.

MidnightBSD 0.3 December 9, 2006 MidnightBSD 0.3