1.\" Copyright (c) 1980, 1991, 1993, 1994 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)chown.2 8.4 (Berkeley) 4/19/94 33.\" $FreeBSD: src/lib/libc/sys/chown.2,v 1.12.2.6 2001/12/14 18:34:00 ru Exp $ 34.\" $DragonFly: src/lib/libc/sys/chown.2,v 1.2 2003/06/17 04:26:47 dillon Exp $ 35.\" 36.Dd April 19, 1994 37.Dt CHOWN 2 38.Os 39.Sh NAME 40.Nm chown , 41.Nm fchown , 42.Nm lchown 43.Nd change owner and group of a file 44.Sh LIBRARY 45.Lb libc 46.Sh SYNOPSIS 47.In unistd.h 48.Ft int 49.Fn chown "const char *path" "uid_t owner" "gid_t group" 50.Ft int 51.Fn fchown "int fd" "uid_t owner" "gid_t group" 52.Ft int 53.Fn lchown "const char *path" "uid_t owner" "gid_t group" 54.Sh DESCRIPTION 55The owner ID and group ID of the file 56named by 57.Fa path 58or referenced by 59.Fa fd 60is changed as specified by the arguments 61.Fa owner 62and 63.Fa group . 64The owner of a file may change the 65.Fa group 66to a group of which 67he or she is a member, 68but the change 69.Fa owner 70capability is restricted to the super-user. 71.Pp 72.Fn Chown 73clears the set-user-id and set-group-id bits 74on the file 75to prevent accidental or mischievous creation of 76set-user-id and set-group-id programs if not executed 77by the super-user. 78.Fn chown 79follows symbolic links to operate on the target of the link 80rather than the link itself. 81.Pp 82.Fn Fchown 83is particularly useful when used in conjunction 84with the file locking primitives (see 85.Xr flock 2 ) . 86.Pp 87.Fn Lchown 88is similar to 89.Fn chown 90but does not follow symbolic links. 91.Pp 92One of the owner or group id's 93may be left unchanged by specifying it as -1. 94.Sh RETURN VALUES 95.Rv -std 96.Sh ERRORS 97.Fn Chown 98and 99.Fn lchown 100will fail and the file will be unchanged if: 101.Bl -tag -width Er 102.It Bq Er ENOTDIR 103A component of the path prefix is not a directory. 104.It Bq Er ENAMETOOLONG 105A component of a pathname exceeded 255 characters, 106or an entire path name exceeded 1023 characters. 107.It Bq Er ENOENT 108The named file does not exist. 109.It Bq Er EACCES 110Search permission is denied for a component of the path prefix. 111.It Bq Er ELOOP 112Too many symbolic links were encountered in translating the pathname. 113.It Bq Er EPERM 114The effective user ID is not the super-user. 115.It Bq Er EROFS 116The named file resides on a read-only file system. 117.It Bq Er EFAULT 118.Fa Path 119points outside the process's allocated address space. 120.It Bq Er EIO 121An I/O error occurred while reading from or writing to the file system. 122.El 123.Pp 124.Fn Fchown 125will fail if: 126.Bl -tag -width Er 127.It Bq Er EBADF 128.Fa fd 129does not refer to a valid descriptor. 130.It Bq Er EINVAL 131.Fa fd 132refers to a socket, not a file. 133.It Bq Er EPERM 134The effective user ID is not the super-user. 135.It Bq Er EROFS 136The named file resides on a read-only file system. 137.It Bq Er EIO 138An I/O error occurred while reading from or writing to the file system. 139.El 140.Sh SEE ALSO 141.Xr chgrp 1 , 142.Xr chmod 2 , 143.Xr flock 2 , 144.Xr chown 8 145.Sh STANDARDS 146The 147.Fn chown 148function call is expected to conform to 149.St -p1003.1-90 . 150.Sh HISTORY 151A 152.Fn chown 153function call appeared in 154.At v7 . 155The 156.Fn fchown 157function call 158appeared in 159.Bx 4.2 . 160.Pp 161The 162.Fn chown 163function was changed to follow symbolic links in 164.Bx 4.4 . 165The 166.Fn lchown 167function was added in 168.Fx 3.0 169to compensate for the loss of functionality. 170