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glibc  2.9
geteuids.c
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00001 /* Copyright (C) 1993, 94, 96, 97, 98, 2000 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <hurd.h>
00020 #include <hurd/id.h>
00021 #include <string.h>
00022 
00023 int
00024 geteuids (int n, uid_t *uidset)
00025 {
00026   error_t err;
00027   int nuids;
00028   void *crit;
00029 
00030   crit = _hurd_critical_section_lock ();
00031   __mutex_lock (&_hurd_id.lock);
00032 
00033   if (err = _hurd_check_ids ())
00034     {
00035       __mutex_unlock (&_hurd_id.lock);
00036       _hurd_critical_section_unlock (crit);
00037       return __hurd_fail (err);
00038     }
00039 
00040   nuids = _hurd_id.gen.nuids;
00041 
00042   if (n != 0)
00043     {
00044       /* Copy the uids onto stack storage and then release the idlock.  */
00045       uid_t uids[nuids];
00046       memcpy (uids, _hurd_id.gen.uids, sizeof (uids));
00047       __mutex_unlock (&_hurd_id.lock);
00048       _hurd_critical_section_unlock (crit);
00049 
00050       /* Now that the lock is released, we can safely copy the
00051         uid set into the user's array, which might fault.  */
00052       if (nuids > n)
00053        nuids = n;
00054       memcpy (uidset, uids, nuids * sizeof (uid_t));
00055     }
00056   else
00057     {
00058       __mutex_unlock (&_hurd_id.lock);
00059       _hurd_critical_section_unlock (crit);
00060     }
00061 
00062   return nuids;
00063 }
00064 
00065 /* XXX Remove this alias when we bump the libc soname.  */
00066 
00067 #if defined SHARED && DO_VERSIONING
00068 weak_alias (geteuids, __getuids)
00069 #endif