CHOWN(2)                   Linux Programmer's Manual                  CHOWN(2)
NAME
       chown, fchown, lchown - change ownership of a file

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

DESCRIPTION
       These  system calls change the owner and group of the file specified by
       path or by  fd.   Only  a  privileged  process  (Linux:  one  with  the
       CAP_CHOWN  capability)  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.  A privileged process (Linux: with CAP_CHOWN) may change
       the group arbitrarily.

       If the owner or group is specified as -1, then that ID is not  changed.

       When  the  owner  or  group of an executable file are changed by a non-
       superuser, 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 indi-
       cates mandatory locking, and is not cleared by a chown().

RETURN VALUE
       On success, zero is returned.  On error, -1 is returned, and  errno  is
       set appropriately.

ERRORS
       Depending  on  the file system, other errors can be returned.  The more
       general errors for chown() are listed below.

       EACCES Search permission is denied on a component of the  path  prefix.
              (See also path_resolution(2).)

       EFAULT path points outside your accessible address space.

       ELOOP  Too many symbolic links were encountered in resolving path.

       ENAMETOOLONG
              path is too long.

       ENOENT The file does not exist.

       ENOMEM Insufficient kernel memory was available.

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

       EPERM  The  calling  process did not have the required permissions (see
              above) to change owner and/or group.

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

       The general errors for fchown() are listed below:

       EBADF  The descriptor is not valid.

       EIO    A low-level I/O error occurred while modifying the inode.

       ENOENT See above.

       EPERM  See above.

       EROFS  See above.

NOTES
       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 is defined.

CONFORMING TO
       4.4BSD, SVr4, POSIX.1-2001.

       The 4.4BSD version can only be used by the superuser (that is, ordinary
       users cannot give away files).

RESTRICTIONS
       The  chown()  semantics  are  deliberately violated on NFS file systems
       which have UID mapping enabled.  Additionally,  the  semantics  of  all
       system  calls  which  access  the  file  contents are violated, because
       chown() may cause immediate access revocation on  already  open  files.
       Client  side  caching may lead to a delay between the time where owner-
       ship 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.

SEE ALSO
       chmod(2), fchownat(2), flock(2), path_resolution(2)

Linux 2.6.7                       2004-06-23                          CHOWN(2)