sysdeps/mach/hurd/htl/pt-mutex-consistent.c

   1 /* pthread_mutex_consistent.  Hurd version.
   2    Copyright (C) 2016-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library;  if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <pthread.h>
  20 #include <stdlib.h>
  21 #include <assert.h>
  22 #include <pt-internal.h>
  23 #include "pt-mutex.h"
  24 #include <hurdlock.h>
  25
  26 int
  27 pthread_mutex_consistent (pthread_mutex_t *mtxp)
  28 {
  29   int ret = EINVAL;
  30   unsigned int val = mtxp->__lock;
  31
  32   if ((mtxp->__flags & PTHREAD_MUTEX_ROBUST) != 0 &&
  33       (val & LLL_DEAD_OWNER) != 0 &&
  34       atomic_compare_and_exchange_bool_acq (&mtxp->__lock,
  35                                             __getpid () | LLL_WAITERS,
  36                                             val) == 0)
  37     {
  38       /* The mutex is now ours, and it's consistent. */
  39       mtxp->__owner_id = _pthread_self ()->thread;
  40       mtxp->__cnt = 1;
  41       ret = 0;
  42     }
  43
  44   return ret;
  45 }
  46
  47 weak_alias (pthread_mutex_consistent, pthread_mutex_consistent_np)