1 /* group-member.c -- determine whether group id is in calling user's group list
2 Copyright (C) 1994, 1997, 1998, 2003 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software Foundation,
16 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
22 #include "group-member.h"
26 #include <sys/types.h>
44 free_group_info (struct group_info const *g)
50 get_group_info (struct group_info *gi)
53 int n_group_slots = getgroups (0, NULL);
56 if (n_group_slots < 0)
59 /* Avoid xnmalloc, as it goes awry when SIZE_MAX < n_group_slots. */
60 if (xalloc_oversized (n_group_slots, sizeof *group))
62 group = xmalloc (n_group_slots * sizeof *group);
63 n_groups = getgroups (n_group_slots, group);
65 /* In case of error, the user loses. */
72 gi->n_groups = n_groups;
78 #endif /* not HAVE_GETGROUPS */
80 /* Return non-zero if GID is one that we have in our groups list.
81 If there is no getgroups function, return non-zero if GID matches
82 either of the current or effective group IDs. */
85 group_member (gid_t gid)
87 #ifndef HAVE_GETGROUPS
88 return ((gid == getgid ()) || (gid == getegid ()));
94 if (! get_group_info (&gi))
97 /* Search through the list looking for GID. */
99 for (i = 0; i < gi.n_groups; i++)
101 if (gid == gi.group[i])
108 free_group_info (&gi);
111 #endif /* HAVE_GETGROUPS */
119 main (int argc, char **argv)
123 program_name = argv[0];
125 for (i=1; i<argc; i++)
129 gid = atoi (argv[i]);
130 printf ("%d: %s\n", gid, group_member (gid) ? "yes" : "no");