xref: /freebsd/lib/libc/gen/initgroups.c (revision dc36d6f9bb1753f3808552f3afd30eda9a7b206a)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1983, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/param.h>
33 
34 #include "namespace.h"
35 #include <err.h>
36 #include "un-namespace.h"
37 #include <errno.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <unistd.h>
41 
42 int
initgroups(const char * uname,gid_t agroup)43 initgroups(const char *uname, gid_t agroup)
44 {
45 	int ngroups, ret;
46 	long ngroups_max;
47 	gid_t *groups;
48 
49 	/*
50 	 * Provide space for one group more than possible to allow
51 	 * setgroups to fail and set errno.
52 	 */
53 	ngroups_max = sysconf(_SC_NGROUPS_MAX) + 2;
54 	if ((groups = malloc(sizeof(*groups) * ngroups_max)) == NULL)
55 		return (ENOMEM);
56 
57 	ngroups = (int)ngroups_max;
58 	getgrouplist(uname, agroup, groups, &ngroups);
59 	ret = setgroups(ngroups, groups);
60 	free(groups);
61 	return (ret);
62 }
63