chown, fchown, lchown - change ownership of a file
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);
The owner of the file specified by path or by fd is
changed. Only the super-user may change the owner of a
file. The owner of a file may change the group of the
file to any group of which that owner is a member. The
super-user may change the group arbitrarily.
If the owner or group is specified as -1, then that ID is
When the owner or group of an executable file are changed
by a non-super-user, the S_ISUID and S_ISGID mode bits are
cleared. POSIX does not specify whether this also should
happen when root does the chown; the Linux behaviour
depends on the kernel version. In case of a non-group-
executable file (with clear S_IXGRP bit) the S_ISGID bit
indicates mandatory locking, and is not cleared by a
On success, zero is returned. On error, -1 is returned,
and errno is set appropriately.
Depending on the file system, other errors can be
returned. The more general errors for chown are listed
EPERM The effective UID does not match the owner of the
file, and is not zero; or the owner or group were
EROFS The named file resides on a read-only file system.
EFAULT path points outside your accessible address space.
path is too long.
ENOENT The file does not exist.
A component of the path prefix is not a directory.
EACCES Search permission is denied on a component of the
ELOOP Too many symbolic links were encountered in resolv
The general errors for fchown are listed below:
EBADF The descriptor is not valid.
ENOENT See above.
EPERM See above.
EROFS See above.
EIO A low-level I/O error occurred while modifying the
In versions of Linux prior to 2.1.81 (and distinct from
2.1.46), chown did not follow symbolic links. Since Linux
2.1.81, chown does follow symbolic links, and there is a
new system call lchown that does not follow symbolic
links. Since Linux 2.1.86, this new call (that has the
same semantics as the old chown) has got the same syscall
number, and chown got the newly introduced number.
The prototype for fchown is only available if _BSD_SOURCE
The chown call conforms to SVr4, SVID, POSIX, X/OPEN. The
4.4BSD version can only be used by the superuser (that is,
ordinary users cannot give away files). SVr4 documents
EINVAL, EINTR, ENOLINK and EMULTIHOP returns, but no
ENOMEM. POSIX.1 does not document ENOMEM or ELOOP error
The fchown call conforms to 4.4BSD and SVr4. SVr4 docu
ments additional EINVAL, EIO, EINTR, and ENOLINK error
The chown() semantics are deliberately violated on NFS
file systems which have UID mapping enabled. Addition
ally, the semantics of all system calls which access the
file contents are violated, because chown() may cause
ownership have been changed to allow access for a user and
the time where the file can actually be accessed by the
user on other clients.