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.\" @(#)setregid.2 8.2 (Berkeley) 4/16/94 33.\" $FreeBSD: src/lib/libc/sys/setregid.2,v 1.6.2.4 2001/12/14 18:34:01 ru Exp $ 34.\" $DragonFly: src/lib/libc/sys/setregid.2,v 1.2 2003/06/17 04:26:47 dillon Exp $ 35.\" 36.Dd April 16, 1994 37.Dt SETREGID 2 38.Os 39.Sh NAME 40.Nm setregid 41.Nd set real and effective group ID 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In unistd.h 46.Ft int 47.Fn setregid "gid_t rgid" "gid_t egid" 48.Sh DESCRIPTION 49The real and effective group ID's of the current process 50are set to the arguments. 51Unprivileged users may change the real group 52ID to the effective group ID and vice-versa; only the super-user may 53make other changes. 54.Pp 55Supplying a value of -1 for either the real or effective 56group ID forces the system to substitute the current 57ID in place of the -1 parameter. 58.Pp 59The 60.Fn setregid 61function was intended to allow swapping 62the real and effective group IDs 63in set-group-ID programs to temporarily relinquish the set-group-ID value. 64This function did not work correctly, 65and its purpose is now better served by the use of the 66.Fn setegid 67function (see 68.Xr setuid 2 ) . 69.Pp 70When setting the real and effective group IDs to the same value, 71the standard 72.Fn setgid 73function is preferred. 74.Sh RETURN VALUES 75.Rv -std setregid 76.Sh ERRORS 77.Bl -tag -width Er 78.It Bq Er EPERM 79The current process is not the super-user and a change 80other than changing the effective group-id to the real group-id 81was specified. 82.El 83.Sh SEE ALSO 84.Xr getgid 2 , 85.Xr issetugid 2 , 86.Xr setegid 2 , 87.Xr setgid 2 , 88.Xr setuid 2 89.Sh HISTORY 90The 91.Fn setregid 92system call appeared in 93.Bx 4.2 . 94