getgrouplist.c revision 145832 
1/*-
2 * Copyright (c) 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#if defined(LIBC_SCCS) && !defined(lint)
35static char sccsid[] = "@(#)getgrouplist.c	8.2 (Berkeley) 12/8/94";
36#endif /* LIBC_SCCS and not lint */
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD: head/lib/libc/gen/getgrouplist.c 145832 2005-05-03 16:20:03Z delphij $");
39
40/*
41 * get credential
42 */
43#include <sys/types.h>
44
45#include <grp.h>
46#include <string.h>
47#include <unistd.h>
48
49int
50getgrouplist(const char *uname, gid_t agroup, gid_t *groups, int *grpcnt)
51{
52	const struct group *grp;
53	int i, maxgroups, ngroups, ret;
54
55	ret = 0;
56	ngroups = 0;
57	maxgroups = *grpcnt;
58	/*
59	 * When installing primary group, duplicate it;
60	 * the first element of groups is the effective gid
61	 * and will be overwritten when a setgid file is executed.
62	 */
63	groups[ngroups++] = agroup;
64	if (maxgroups > 1)
65		groups[ngroups++] = agroup;
66	/*
67	 * Scan the group file to find additional groups.
68	 */
69	setgrent();
70	while ((grp = getgrent()) != NULL) {
71		for (i = 0; i < ngroups; i++) {
72			if (grp->gr_gid == groups[i])
73				goto skip;
74		}
75		for (i = 0; grp->gr_mem[i]; i++) {
76			if (!strcmp(grp->gr_mem[i], uname)) {
77				if (ngroups >= maxgroups) {
78					ret = -1;
79					break;
80				}
81				groups[ngroups++] = grp->gr_gid;
82				break;
83			}
84		}
85skip:
86		;
87	}
88	endgrent();
89	*grpcnt = ngroups;
90	return (ret);
91}
92