/* `group_member' -- test if process is in a given group.

   Copyright (C) 1995-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <sys/types.h>

#include <unistd.h>

#include <stdlib.h>

#include <limits.h>

#ifndef NGROUPS_MAX

#define NGROUPS_MAX	16	/* First guess.  */

#endif

int

__group_member (gid_t gid)

{

  int n, size;

  gid_t *groups;

  size = NGROUPS_MAX;

  do

    {

      groups = __alloca (size * sizeof *groups);

      n = __getgroups (size, groups);

      size *= 2;

    }

  while (n == size / 2);

  while (n-- > 0)

    if (groups[n] == gid)

      return 1;

  return 0;

}

weak_alias (__group_member, group_member)