.\" Copyright (c) 1980, 1991, 1993, 1994 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)chown.2 8.4 (Berkeley) 4/19/94 .\" .Dd April 19, 1994 .Dt CHOWN 2 .Os .Sh NAME .Nm chown , .Nm fchown , .Nm lchown .Nd change owner and group of a file .Sh SYNOPSIS .In unistd.h .Ft int .Fo chown .Fa "const char *path" .Fa "uid_t owner" .Fa "gid_t group" .Fc .Ft int .Fo fchown .Fa "int fildes" .Fa "uid_t owner" .Fa "gid_t group" .Fc .Ft int .Fo lchown .Fa "const char *path" .Fa "uid_t owner" .Fa "gid_t group" .Fc .Sh DESCRIPTION The owner ID and group ID of the file named by .Fa path or referenced by .Fa fildes is changed as specified by the arguments .Fa owner and .Fa group . The owner of a file may change the .Fa group to a group of which he or she is a member, but the change .Fa owner capability is restricted to the super-user. .Pp The .Fn 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 .Fn chown system call follows symbolic links to operate on the target of the link rather than the link itself. .Pp The .Fn fchown system call is particularly useful when used in conjunction with the file locking primitives (see .Xr flock 2 ) . .Pp The .Fn lchown system call is similar to .Fn chown but does not follow symbolic links. .Pp One of the owner or group id's may be left unchanged by specifying it as -1. .Sh RETURN VALUES .Rv -std .Sh ERRORS .Pp The .Fn chown and .Fn lchown system calls will fail if: .Bl -tag -width Er .\" ========== .It Bq Er EACCES Search permission is denied for a component of the path prefix. .It Bq Er EFAULT The .Fa path argument points outside the process's allocated address space. .\" ========== .It Bq Er ELOOP Too many symbolic links are encountered in translating the pathname. This is taken to be indicative of a looping symbolic link. .\" ========== .It Bq Er ENAMETOOLONG A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters. .\" ========== .It Bq Er ENOENT A component of .Fa path does not exist. .\" ========== .It Bq Er ENOTDIR A component of the path prefix is not a directory. .El .Pp The .Fn fchown system call will fail if: .Bl -tag -width Er .\" ========== .It Bq Er EBADF The .Fa fildes argument does not refer to a valid descriptor. .\" ========== .It Bq Er EINVAL The .Fa fildes argument refers to a socket, not a file. .El .Pp Any of these calls will fail if: .Bl -tag -width Er .\" ========== .It Bq Er EINTR Its execution is interrupted by a signal. .\" ========== .It Bq Er EIO An I/O error occurs while reading from or writing to the file system. .\" ========== .It Bq Er EPERM The effective user ID does not match the owner of the file and the calling process does not have appropriate (i.e., root) privileges. .\" ========== .It Bq Er EROFS The named file resides on a read-only file system. .El .Sh SEE ALSO .Xr chgrp 1 , .Xr chmod 2 , .Xr flock 2 , .Xr chown 8 .Sh STANDARDS The .Fn chown system call is expected to conform to .St -p1003.1-90 . .Sh HISTORY The .Fn chown function appeared in .At v7 . The .Fn fchown system call appeared in .Bx 4.2 . .Pp The .Fn chown and .Fn fchown system calls were changed to follow symbolic links in .Bx 4.4 . The .Fn lchown system call was added in .Fx 3.0 to compensate for the loss of functionality.