getgroups.c

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/*
 * Copyright (C) 2002 by Martin Pool
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/**
 * @file getgroups.c
 *
 * Print out the gids of all groups for the current user.  This is
 * like `id -G` on Linux, but it's too hard to find a portable
 * equivalent.
 **/

#include "rsync.h"

int
main(UNUSED(int argc), UNUSED(char *argv[]))
{
        int n, i;
        gid_t *list;
        gid_t gid = MY_GID();
        int gid_in_list = 0;

#ifdef HAVE_GETGROUPS
        if ((n = getgroups(0, NULL)) < 0) {
                perror("getgroups");
                return 1;
        }
#else
        n = 0;
#endif

        list = (gid_t*)malloc(sizeof (gid_t) * (n + 1));
        if (!list) {
                fprintf(stderr, "out of memory!\n");
                exit(1);
        }

#ifdef HAVE_GETGROUPS
        if (n > 0)
                n = getgroups(n, list);
#endif

        for (i = 0; i < n; i++)  {
                printf("%lu ", (unsigned long)list[i]);
                if (list[i] == gid)
                        gid_in_list = 1;
        }
        /* The default gid might not be in the list on some systems. */
        if (!gid_in_list)
                printf("%lu", (unsigned long)gid);
        printf("\n");
                
        return 0;
}

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