xref: /freebsd/lib/libc/gen/getgrouplist.c (revision f0adf7f5cdd241db2f2c817683191a6ef64a4e95)
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)
35 static char sccsid[] = "@(#)getgrouplist.c	8.2 (Berkeley) 12/8/94";
36 #endif /* LIBC_SCCS and not lint */
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 /*
41  * get credential
42  */
43 #include <sys/types.h>
44 #include <string.h>
45 #include <grp.h>
46 
47 int
48 getgrouplist(uname, agroup, groups, grpcnt)
49 	const char *uname;
50 	gid_t agroup;
51 	gid_t *groups;
52 	int *grpcnt;
53 {
54 	struct group *grp;
55 	int i, maxgroups, ngroups, ret;
56 
57 	ret = 0;
58 	ngroups = 0;
59 	maxgroups = *grpcnt;
60 	/*
61 	 * When installing primary group, duplicate it;
62 	 * the first element of groups is the effective gid
63 	 * and will be overwritten when a setgid file is executed.
64 	 */
65 	groups[ngroups++] = agroup;
66 	if (maxgroups > 1)
67 		groups[ngroups++] = agroup;
68 	/*
69 	 * Scan the group file to find additional groups.
70 	 */
71 	setgrent();
72 	while ((grp = getgrent()) != NULL) {
73 		for (i = 0; i < ngroups; i++) {
74 			if (grp->gr_gid == groups[i])
75 				goto skip;
76 		}
77 		for (i = 0; grp->gr_mem[i]; i++) {
78 			if (!strcmp(grp->gr_mem[i], uname)) {
79 				if (ngroups >= maxgroups) {
80 					ret = -1;
81 					break;
82 				}
83 				groups[ngroups++] = grp->gr_gid;
84 				break;
85 			}
86 		}
87 skip:
88 		;
89 	}
90 	endgrent();
91 	*grpcnt = ngroups;
92 	return (ret);
93 }
94