1  /* Copyright (C) 1993-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <hurd.h>
      19  #include <hurd/id.h>
      20  #include <string.h>
      21  
      22  int
      23  geteuids (int n, uid_t *uidset)
      24  {
      25    error_t err;
      26    int nuids;
      27    void *crit;
      28  
      29  retry:
      30    crit = _hurd_critical_section_lock ();
      31    __mutex_lock (&_hurd_id.lock);
      32  
      33    if (err = _hurd_check_ids ())
      34      {
      35        __mutex_unlock (&_hurd_id.lock);
      36        _hurd_critical_section_unlock (crit);
      37        if (err == EINTR)
      38  	/* Got a signal while inside an RPC of the critical section, retry again */
      39  	goto retry;
      40        return __hurd_fail (err);
      41      }
      42  
      43    nuids = _hurd_id.gen.nuids;
      44  
      45    if (n != 0)
      46      {
      47        /* Copy the uids onto stack storage and then release the idlock.  */
      48        uid_t uids[nuids];
      49        memcpy (uids, _hurd_id.gen.uids, sizeof (uids));
      50        __mutex_unlock (&_hurd_id.lock);
      51        _hurd_critical_section_unlock (crit);
      52  
      53        /* Now that the lock is released, we can safely copy the
      54  	 uid set into the user's array, which might fault.  */
      55        if (nuids > n)
      56  	nuids = n;
      57        memcpy (uidset, uids, nuids * sizeof (uid_t));
      58      }
      59    else
      60      {
      61        __mutex_unlock (&_hurd_id.lock);
      62        _hurd_critical_section_unlock (crit);
      63      }
      64  
      65    return nuids;
      66  }
      67  
      68  /* XXX Remove this alias when we bump the libc soname.  */
      69  
      70  #ifdef SHARED
      71  weak_alias (geteuids, __getuids)
      72  #endif