xref: /csrg-svn/lib/libc/gen/initgroups.c (revision 38787)
1 /*
2  * Copyright (c) 1983 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  */
17 
18 #if defined(LIBC_SCCS) && !defined(lint)
19 static char sccsid[] = "@(#)initgroups.c	5.5 (Berkeley) 08/26/89";
20 #endif /* LIBC_SCCS and not lint */
21 
22 /*
23  * initgroups
24  */
25 #include <stdio.h>
26 #include <sys/param.h>
27 #include <grp.h>
28 
29 struct group *getgrent();
30 
31 initgroups(uname, agroup)
32 	char *uname;
33 	int agroup;
34 {
35 	int groups[NGROUPS], ngroups = 0;
36 	register struct group *grp;
37 	register int i;
38 
39 	/*
40 	 * If installing primary group, duplicate it;
41 	 * the first element of groups is the effective gid
42 	 * and will be overwritten when a setgid file is executed.
43 	 */
44 	if (agroup >= 0) {
45 		groups[ngroups++] = agroup;
46 		groups[ngroups++] = agroup;
47 	}
48 	setgrent();
49 	while (grp = getgrent()) {
50 		if (grp->gr_gid == agroup)
51 			continue;
52 		for (i = 0; grp->gr_mem[i]; i++)
53 			if (!strcmp(grp->gr_mem[i], uname)) {
54 				if (ngroups == NGROUPS) {
55 fprintf(stderr, "initgroups: %s is in too many groups\n", uname);
56 					goto toomany;
57 				}
58 				groups[ngroups++] = grp->gr_gid;
59 			}
60 	}
61 toomany:
62 	endgrent();
63 	if (setgroups(ngroups, groups) < 0) {
64 		perror("setgroups");
65 		return (-1);
66 	}
67 	return (0);
68 }
69