/*
 * Copyright (c) 1982, 1986, 1989, 1990, 1991 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.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char *rcsid = "$OpenBSD: setregid.c,v 1.5 2002/10/30 20:15:29 millert Exp $";
#endif /* LIBC_SCCS and not lint */

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

#ifndef NO_WARN_REFERENCES
__warn_references(setregid, "warning: this program uses setregid(), which is deprecated.");
#endif

int
setregid(gid_t rgid, gid_t egid)
{
	int error;
	gid_t sgid, cur_rgid, cur_egid, cur_sgid;

	if (error == (getresgid(&cur_rgid, &cur_egid, &cur_sgid)) != 0)
		return (error);

	/*
	 * The saved gid presents a bit of a dilemma, as it did not
	 * appear in 4.3BSD.  We only set the saved gid when the real
	 * gid is specified and either its value would change, or,
	 * where the saved and effective gids are different.
	 */
	if (rgid != (gid_t)-1 && (rgid != cur_rgid ||
	    cur_sgid != (egid != (gid_t)-1 ? egid : cur_egid)))
		sgid = rgid;
	else
		sgid = (gid_t)-1;

	return (setresgid(rgid, egid, sgid));
}