native_client_sdk/src/libraries/third_party/pthreads-win32/pthread_mutex_destroy.c

   1 /*
   2  * pthread_mutex_destroy.c
   3  *
   4  * Description:
   5  * This translation unit implements mutual exclusion (mutex) primitives.
   6  *
   7  * --------------------------------------------------------------------------
   8  *
   9  *      Pthreads-win32 - POSIX Threads Library for Win32
  10  *      Copyright(C) 1998 John E. Bossom
  11  *      Copyright(C) 1999,2005 Pthreads-win32 contributors
  12  *
  13  *      Contact Email: rpj@callisto.canberra.edu.au
  14  *
  15  *      The current list of contributors is contained
  16  *      in the file CONTRIBUTORS included with the source
  17  *      code distribution. The list can also be seen at the
  18  *      following World Wide Web location:
  19  *      http://sources.redhat.com/pthreads-win32/contributors.html
  20  *
  21  *      This library is free software; you can redistribute it and/or
  22  *      modify it under the terms of the GNU Lesser General Public
  23  *      License as published by the Free Software Foundation; either
  24  *      version 2 of the License, or (at your option) any later version.
  25  *
  26  *      This library is distributed in the hope that it will be useful,
  27  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  29  *      Lesser General Public License for more details.
  30  *
  31  *      You should have received a copy of the GNU Lesser General Public
  32  *      License along with this library in the file COPYING.LIB;
  33  *      if not, write to the Free Software Foundation, Inc.,
  34  *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  35  */
  36
  37 #include "pthread.h"
  38 #include "implement.h"
  39
  40
  41 int
  42 pthread_mutex_destroy (pthread_mutex_t * mutex)
  43 {
  44   int result = 0;
  45   pthread_mutex_t mx;
  46
  47   /*
  48    * Let the system deal with invalid pointers.
  49    */
  50
  51   /*
  52    * Check to see if we have something to delete.
  53    */
  54   if (*mutex < PTHREAD_ERRORCHECK_MUTEX_INITIALIZER)
  55     {
  56       mx = *mutex;
  57
  58       result = pthread_mutex_trylock (&mx);
  59
  60       /*
  61        * If trylock succeeded and the mutex is not recursively locked it
  62        * can be destroyed.
  63        */
  64       if (0 == result || ENOTRECOVERABLE == result)
  65         {
  66           if (mx->kind != PTHREAD_MUTEX_RECURSIVE || 1 == mx->recursive_count)
  67             {
  68               /*
  69                * FIXME!!!
  70                * The mutex isn't held by another thread but we could still
  71                * be too late invalidating the mutex below since another thread
  72                * may already have entered mutex_lock and the check for a valid
  73                * *mutex != NULL.
  74                */
  75               *mutex = NULL;
  76
  77               result = (0 == result)?pthread_mutex_unlock(&mx):0;
  78
  79               if (0 == result)
  80                 {
  81                   if (mx->robustNode != NULL)
  82                     {
  83                       free(mx->robustNode);
  84                     }
  85                   if (!CloseHandle (mx->event))
  86                     {
  87                       *mutex = mx;
  88                       result = EINVAL;
  89                     }
  90                   else
  91                     {
  92                       free (mx);
  93                     }
  94                 }
  95               else
  96                 {
  97                   /*
  98                    * Restore the mutex before we return the error.
  99                    */
 100                   *mutex = mx;
 101                 }
 102             }
 103           else                  /* mx->recursive_count > 1 */
 104             {
 105               /*
 106                * The mutex must be recursive and already locked by us (this thread).
 107                */
 108               mx->recursive_count--;    /* Undo effect of pthread_mutex_trylock() above */
 109               result = EBUSY;
 110             }
 111         }
 112     }
 113   else
 114     {
 115       ptw32_mcs_local_node_t node;
 116
 117       /*
 118        * See notes in ptw32_mutex_check_need_init() above also.
 119        */
 120
 121       ptw32_mcs_lock_acquire(&ptw32_mutex_test_init_lock, &node);
 122
 123       /*
 124        * Check again.
 125        */
 126       if (*mutex >= PTHREAD_ERRORCHECK_MUTEX_INITIALIZER)
 127         {
 128           /*
 129            * This is all we need to do to destroy a statically
 130            * initialised mutex that has not yet been used (initialised).
 131            * If we get to here, another thread
 132            * waiting to initialise this mutex will get an EINVAL.
 133            */
 134           *mutex = NULL;
 135         }
 136       else
 137         {
 138           /*
 139            * The mutex has been initialised while we were waiting
 140            * so assume it's in use.
 141            */
 142           result = EBUSY;
 143         }
 144       ptw32_mcs_lock_release(&node);
 145     }
 146
 147   return (result);
 148 }