orte/liborte/rtl/pthread_rwlock_destroy.c

   1 /*
   2  * pthread_rwlock_destroy.c
   3  *
   4  * Description:
   5  * This translation unit implements read/write lock primitives.
   6  *
   7  * --------------------------------------------------------------------------
   8  *
   9  *      Pthreads-win32 - POSIX Threads Library for Win32
  10  *      Copyright(C) 1998 John E. Bossom
  11  *      Copyright(C) 1999,2002 Pthreads-win32 contributors
  12  *
  13  *      Contact Email: rpj@ise.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 <errno.h>
  38 //#include <limits.h>
  39
  40 //#include "pthread.h"
  41 //#include "implement.h"
  42
  43 #include "orte.h"
  44
  45 int
  46 pthread_rwlock_destroy(pthread_rwlock_t *rwlock)
  47 {
  48     pthread_rwlock_t rwl;
  49     int result = 0, result1 = 0, result2 = 0;
  50
  51     if (rwlock == NULL || *rwlock == NULL)
  52       {
  53         return EINVAL;
  54       }
  55
  56     if (*rwlock != PTHREAD_RWLOCK_INITIALIZER)
  57       {
  58         rwl = *rwlock;
  59
  60         if (rwl->nMagic != PTW32_RWLOCK_MAGIC)
  61           {
  62             return EINVAL;
  63           }
  64
  65         if ((result = pthread_mutex_lock(&(rwl->mtxExclusiveAccess))) != 0)
  66           {
  67             return result;
  68           }
  69
  70         if ((result = pthread_mutex_lock(&(rwl->mtxSharedAccessCompleted))) != 0)
  71           {
  72             (void) pthread_mutex_unlock(&(rwl->mtxExclusiveAccess));
  73             return result;
  74           }
  75
  76         /*
  77          * Check whether any threads own/wait for the lock (wait for ex.access);
  78          * report "BUSY" if so.
  79          */
  80         if (rwl->nExclusiveAccessCount > 0
  81             || rwl->nSharedAccessCount > rwl->nCompletedSharedAccessCount)
  82           {
  83             result = pthread_mutex_unlock(&(rwl->mtxSharedAccessCompleted));
  84             result1 = pthread_mutex_unlock(&(rwl->mtxExclusiveAccess));
  85             result2 = EBUSY;
  86           }
  87         else
  88           {
  89             rwl->nMagic = 0;
  90
  91             if ((result = pthread_mutex_unlock(&(rwl->mtxSharedAccessCompleted))) != 0)
  92               {
  93                 pthread_mutex_unlock(&rwl->mtxExclusiveAccess);
  94                 return result;
  95               }
  96
  97             if ((result = pthread_mutex_unlock(&(rwl->mtxExclusiveAccess))) != 0)
  98               {
  99                 return result;
 100               }
 101
 102             *rwlock = NULL; /* Invalidate rwlock before anything else */
 103             result = pthread_cond_destroy(&(rwl->cndSharedAccessCompleted));
 104             result1 = pthread_mutex_destroy(&(rwl->mtxSharedAccessCompleted));
 105             result2 = pthread_mutex_destroy(&(rwl->mtxExclusiveAccess));
 106             (void) free(rwl);
 107           }
 108       }
 109     else
 110       {
 111         /*
 112          * See notes in ptw32_rwlock_check_need_init() above also.
 113          */
 114 //      EnterCriticalSection(&ptw32_rwlock_test_init_lock);
 115
 116         /*
 117          * Check again.
 118          */
 119         if (*rwlock == PTHREAD_RWLOCK_INITIALIZER)
 120           {
 121             /*
 122              * This is all we need to do to destroy a statically
 123              * initialised rwlock that has not yet been used (initialised).
 124              * If we get to here, another thread
 125              * waiting to initialise this rwlock will get an EINVAL.
 126              */
 127             *rwlock = NULL;
 128           }
 129         else
 130           {
 131             /*
 132              * The rwlock has been initialised while we were waiting
 133              * so assume it's in use.
 134              */
 135             result = EBUSY;
 136           }
 137
 138 //      LeaveCriticalSection(&ptw32_rwlock_test_init_lock);
 139       }
 140
 141     return ((result != 0) ? result : ((result1 != 0) ? result1 : result2));
 142 }