/* provide consistent interface to getgroups for systems that don't allow N==0   Copyright (C) 1996, 1999 Free Software Foundation, Inc.   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, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  *//* written by Jim Meyering */#include <config.h>#include <stdio.h>#include <sys/types.h>char *xmalloc ();/* On at least Ultrix 4.3 and NextStep 3.2, getgroups (0, 0) always fails.   On other systems, it returns the number of supplemental groups for the   process.  This function handles that special case and lets the system-   provided function handle all others. */intgetgroups (size_t n, GETGROUPS_T *group){  int n_groups;  GETGROUPS_T *gbuf;#undef getgroups  if (n != 0)    return getgroups (n, group);  n = 20;  gbuf = NULL;  while (1)    {      gbuf = (GETGROUPS_T *) xrealloc (gbuf, n * sizeof (GETGROUPS_T));      n_groups = getgroups (n, gbuf);      if (n_groups < n)	break;      n += 10;    }  free (gbuf);  return n_groups;}