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67 lines
1.9 KiB
C
67 lines
1.9 KiB
C
/* provide consistent interface to getgroups for systems that don't allow N==0
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Copyright (C) 1996, 1999, 2003 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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/* written by Jim Meyering */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <stdio.h>
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#include <sys/types.h>
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#include <errno.h>
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#include <stdlib.h>
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#include "xalloc.h"
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/* On at least Ultrix 4.3 and NextStep 3.2, getgroups (0, 0) always fails.
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On other systems, it returns the number of supplemental groups for the
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process. This function handles that special case and lets the system-
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provided function handle all others. */
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int
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getgroups (int n, GETGROUPS_T *group)
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{
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int n_groups;
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GETGROUPS_T *gbuf;
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int saved_errno;
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#undef getgroups
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if (n != 0)
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return getgroups (n, group);
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n = 20;
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while (1)
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{
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/* No need to worry about address arithmetic overflow here,
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since the ancient systems that we're running on have low
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limits on the number of secondary groups. */
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gbuf = xmalloc (n * sizeof *gbuf);
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n_groups = getgroups (n, gbuf);
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if (n_groups < n)
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break;
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free (gbuf);
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n += 10;
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}
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saved_errno = errno;
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free (gbuf);
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errno = saved_errno;
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return n_groups;
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}
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