1 /*
2  * Copyright (C) 2008 The Android Open Source Project
3  * 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  *  * Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  *  * Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in
12  *    the documentation and/or other materials provided with the
13  *    distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 #include <grp.h>
29 #include <unistd.h>
30 #include <stdlib.h>
31 
32 #define  INIT_GROUPS  2
33 
34 int
initgroups(const char * user,gid_t group)35 initgroups (const char *user, gid_t group)
36 {
37     gid_t   groups0[ INIT_GROUPS ];
38     gid_t*  groups    = groups0;
39     int     ret       = -1;
40     int     numgroups = INIT_GROUPS;
41 
42     if (getgrouplist(user, group, groups, &numgroups) < 0) {
43         groups = malloc(numgroups*sizeof(groups[0]));
44         if (groups == NULL)
45             return -1;
46         if (getgrouplist(user,group,groups,&numgroups) < 0) {
47             goto EXIT;
48         }
49     }
50 
51     ret = setgroups(numgroups, groups);
52 
53 EXIT:
54     if (groups != groups0)
55         free(groups);
56 
57     return ret;
58 }
59