/*	$NetBSD: initgroups.c,v 1.22 2012/06/25 22:32:43 abs Exp $	*/

/*
 * Copyright (c) 1983, 1993
 *	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. 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.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)initgroups.c	8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: initgroups.c,v 1.22 2012/06/25 22:32:43 abs Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"
#include <sys/param.h>

#include <assert.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>

#ifdef __weak_alias
__weak_alias(initgroups,_initgroups)
#endif

int
initgroups(const char *uname, gid_t agroup)
{
	gid_t groups_list[NGROUPS];
	int ngroups;
	gid_t *groups = groups_list;
	int rval;

	_DIAGASSERT(uname != NULL);

	ngroups = NGROUPS;
	if (getgrouplist(uname, agroup, groups, &ngroups) == -1) {
		int maxgroups = ngroups;
		groups = calloc((size_t)maxgroups, sizeof *groups);
		if (groups == NULL)
			return -1;
		if (getgrouplist(uname, agroup, groups, &ngroups) == -1)
			ngroups = maxgroups;
	}
	rval = setgroups(ngroups, groups);
	if (rval == -1 && errno == EINVAL) {
		int ng = (int)sysconf(_SC_NGROUPS_MAX);
		if (ng > 0 && ng < ngroups)
			rval = setgroups(ng, groups);
	}
	if (groups != groups_list)
		free(groups);
	return rval;
}