getgroups.c

   1 /*
   2  * Copyright (C) 2002 by Martin Pool
   3  *
   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 of the License, or
   7  * (at your option) any later version.
   8  *
   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.
  13  *
  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
  16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 /**
  20  * @file getgroups.c
  21  *
  22  * Print out the gids of all groups for the current user.  This is
  23  * like `id -G` on Linux, but it's too hard to find a portable
  24  * equivalent.
  25  **/
  26
  27 #include "rsync.h"
  28
  29 int
  30 main(UNUSED(int argc), UNUSED(char *argv[]))
  31 {
  32         int n, i;
  33         gid_t *list;
  34         gid_t gid = MY_GID();
  35         int gid_in_list = 0;
  36
  37 #ifdef HAVE_GETGROUPS
  38         if ((n = getgroups(0, NULL)) < 0) {
  39                 perror("getgroups");
  40                 return 1;
  41         }
  42 #else
  43         n = 0;
  44 #endif
  45
  46         list = (gid_t*)malloc(sizeof (gid_t) * (n + 1));
  47         if (!list) {
  48                 fprintf(stderr, "out of memory!\n");
  49                 exit(1);
  50         }
  51
  52 #ifdef HAVE_GETGROUPS
  53         if (n > 0)
  54                 n = getgroups(n, list);
  55 #endif
  56
  57         for (i = 0; i < n; i++)  {
  58                 printf("%lu ", (unsigned long)list[i]);
  59                 if (list[i] == gid)
  60                         gid_in_list = 1;
  61         }
  62         /* The default gid might not be in the list on some systems. */
  63         if (!gid_in_list)
  64                 printf("%lu", (unsigned long)gid);
  65         printf("\n");
  66
  67         return 0;
  68 }