xref: /openbsd-src/lib/libc/gen/getgrouplist.c (revision db3296cf5c1dd9058ceecc3a29fe4aaa0bd26000)
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. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char rcsid[] = "$OpenBSD: getgrouplist.c,v 1.9 2003/06/25 21:16:47 deraadt Exp $";
32 #endif /* LIBC_SCCS and not lint */
33 
34 /*
35  * get credential
36  */
37 #include <sys/types.h>
38 #include <string.h>
39 #include <unistd.h>
40 #include <grp.h>
41 
42 int
43 getgrouplist(uname, agroup, groups, grpcnt)
44 	const char *uname;
45 	gid_t agroup;
46 	register gid_t *groups;
47 	int *grpcnt;
48 {
49 	register struct group *grp;
50 	register int i, ngroups;
51 	int ret, maxgroups;
52 	int bail;
53 
54 	ret = 0;
55 	ngroups = 0;
56 	maxgroups = *grpcnt;
57 
58 	/*
59 	 * install primary group
60 	 */
61 	if (ngroups >= maxgroups) {
62 		*grpcnt = ngroups;
63 		return (-1);
64 	}
65 	groups[ngroups++] = agroup;
66 
67 	/*
68 	 * Scan the group file to find additional groups.
69 	 */
70 	setgrent();
71 	while ((grp = getgrent())) {
72 		if (grp->gr_gid == agroup)
73 			continue;
74 		for (bail = 0, i = 0; bail == 0 && i < ngroups; i++)
75 			if (groups[i] == grp->gr_gid)
76 				bail = 1;
77 		if (bail)
78 			continue;
79 		for (i = 0; grp->gr_mem[i]; i++) {
80 			if (!strcmp(grp->gr_mem[i], uname)) {
81 				if (ngroups >= maxgroups) {
82 					ret = -1;
83 					goto out;
84 				}
85 				groups[ngroups++] = grp->gr_gid;
86 				break;
87 			}
88 		}
89 	}
90 out:
91 	endgrent();
92 	*grpcnt = ngroups;
93 	return (ret);
94 }
95