chown(2)							   System Calls 							  chown(2)

NAME

       chown, lchown, fchown, fchownat - change owner and group of a file

SYNOPSIS

       #include <unistd.h>
       #include <sys/types.h>

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

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

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

       int fchownat(int fildes, const char *path, uid_t owner,
	    gid_t group, int flag);

DESCRIPTION

       The chown() function sets the owner ID and group ID of the file specified by path or referenced by the open file descriptor fildes to owner
       and group respectively. If owner or group is specified as -1, chown() does not change the corresponding ID of the file.

       The  lchown() function sets the owner ID and group ID of the named file in the same manner as chown(), unless the named file is a  symbolic
       link.  In  this	case,  lchown() changes the ownership of the symbolic link file itself, while chown() changes the ownership of the file or
       directory to which the symbolic link refers.

       The fchownat() function sets the owner ID and group ID of the named  file  in the same manner as chown(). If, however, the path argument is
       relative,  the  path is resolved relative to the fildes argument rather than the current working directory.  If the fildes argument has the
       special value AT_FDCWD, the path resolution reverts back to current working directory relative.	If the flag argument is set to SYMLNK, the
       function  behaves  like	lchown() with respect to symbolic links. If the path argument is absolute, the fildes argument is ignored.  If the
       path argument is a null pointer, the function behaves like fchown().

       If  chown(), lchown(), fchown(), or fchownat() is invoked by a process that does not have {PRIV_FILE_SETID} asserted in its effective  set,
       the set-user-ID and set-group-ID bits of the file mode, S_ISUID and  S_ISGID respectively, are cleared (see  chmod(2)). Additional restric-
       tions apply when changing the ownership to uid 0.

       The operating system defines several privileges to override restrictions on the chown() family of  functions.  When  the  {PRIV_FILE_CHOWN}
       privilege  is asserted in the effective set of the current process, there are no restrictions except in the special circumstances of chang-
       ing ownership to or from uid 0. When the {PRIV_FILE_CHOWN_SELF} privilege is asserted, ownership changes are restricted	to  the  files	of
       which  the  ownership  matches  the effective user ID of the current process.  If neither privilege is asserted in the effective set of the
       calling process, ownership changes are limited to changes of the group of the file to the list of supplementary group IDs and the effective
       group ID.

       The  operating  system  provides  a  configuration  option, {_POSIX_CHOWN_RESTRICTED}, to control the default behavior of processes and the
       behavior of the NFS server.  If {_POSIX_CHOWN_RESTRICTED} is not in effect, the privilege {PRIV_FILE_CHOWN_SELF} is asserted in the inheri-
       table  set  of  all  processes unless overridden by policy.conf(4) or user_attr(4). To set this configuration option, include the following
       line in /etc/system:

       set rstchown = 1

       To disable this option, include the following line in  /etc/system:

       set rstchown = 0

       See system(4) and  fpathconf(2).

       Upon successful completion, chown(), fchown() and lchown() mark for update the st_ctime field of the file.

RETURN VALUES

       Upon successful completion, 0 is returned. Otherwise, -1 is returned, the owner and group of the named file remain unchanged, and errno	is
       set to indicate the error.

ERRORS

       All of these functions will fail if:

       EPERM	The  effective	user  ID does not match the owner of the file and the {PRIV_FILE_CHOWN} privilege is not asserted in the effective
		set of the calling process, or the {PRIV_FILE_CHOWN_SELF} privilege is not asserted in the effective set of the calling process.

       The chown(), lchown(), and fchownat() functions will fail if:

       EACCES	       Search permission is denied on a component of the path prefix of path.

       EFAULT	       The path argument points to an illegal address and for fchownat(), the file descriptor has the value AT_FDCWD.

       EINTR	       A signal was caught during the execution of the chown() or lchown() function.

       EINVAL	       The group or owner argument is out of range.

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

       ELOOP	       Too many symbolic links were encountered in translating path.

       ENAMETOOLONG    The length of the path  argument  exceeds  {PATH_MAX},  or  the	length	of  a  path  component	exceeds  {NAME_MAX}  while
		       {_POSIX_NO_TRUNC} is in effect.

       ENOLINK	       The path argument points to a remote machine and the link to that machine is no longer active.

       ENOENT	       Either a component of the path prefix or the file referred to by path does not exist or is a null pathname.

       ENOTDIR	       A  component  of  the  path  prefix of path is not a directory, or the path supplied to fchownat() is relative and the file
		       descriptor provided does not refer to a valid directory.

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

       The fchown() and fchownat() functions will fail if:

       EBADF	  For fchown() the fildes argument is not an open file descriptor and.

		  For fchownat(), the path argument is not absolute and the fildes argument is not AT_FDCWD or an open file descriptor.

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

       EINTR	  A signal was caught during execution of the function.

       ENOLINK	  The fildes argument points to a remote machine and the link to that machine is no longer active.

       EINVAL	  The group or owner argument is out of range.

       EROFS	  The named file referred to by fildes resides on a read-only file system.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |See below.		   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |See below.		   |
       +-----------------------------+-----------------------------+

       The chown(), fchown(), and lchown() functions are Standard. The fchownat() function is Evolving.

       The chown() and fchownat() functions are Async-Signal-Safe.

SEE ALSO

       chgrp(1), chown(1), chmod(2), fpathconf(2), system(4), attributes(5), standards(5)

SunOS 5.11							    9 Oct 2008								  chown(2)