orte/liborte/rtl/pthread_rwlock_timedwrlock.c

   1 /*
   2  * pthread_rwlock_timedwrlock.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_timedwrlock(pthread_rwlock_t * rwlock, const struct timespec * abstime)
  47 {
  48     int result;
  49     pthread_rwlock_t rwl;
  50
  51     if (rwlock == NULL || *rwlock == NULL)
  52       {
  53         return EINVAL;
  54       }
  55
  56     /*
  57      * We do a quick check to see if we need to do more work
  58      * to initialise a static rwlock. We check
  59      * again inside the guarded section of ptw32_rwlock_check_need_init()
  60      * to avoid race conditions.
  61      */
  62     if (*rwlock == PTHREAD_RWLOCK_INITIALIZER)
  63       {
  64         result = ptw32_rwlock_check_need_init(rwlock);
  65
  66         if (result != 0 && result != EBUSY)
  67           {
  68             return result;
  69           }
  70       }
  71
  72     rwl = *rwlock;
  73
  74     if (rwl->nMagic != PTW32_RWLOCK_MAGIC)
  75       {
  76         return EINVAL;
  77       }
  78
  79     if ((result = pthread_mutex_timedlock(&(rwl->mtxExclusiveAccess), abstime)) != 0)
  80       {
  81         return result;
  82       }
  83
  84     if ((result = pthread_mutex_timedlock(&(rwl->mtxSharedAccessCompleted), abstime)) != 0)
  85       {
  86         (void) pthread_mutex_unlock(&(rwl->mtxExclusiveAccess));
  87         return result;
  88       }
  89
  90     if (rwl->nExclusiveAccessCount == 0)
  91       {
  92         if (rwl->nCompletedSharedAccessCount > 0)
  93           {
  94             rwl->nSharedAccessCount -= rwl->nCompletedSharedAccessCount;
  95             rwl->nCompletedSharedAccessCount = 0;
  96           }
  97
  98         if (rwl->nSharedAccessCount > 0)
  99           {
 100             rwl->nCompletedSharedAccessCount = -rwl->nSharedAccessCount;
 101
 102             /*
 103              * This routine may be a cancelation point
 104              * according to POSIX 1003.1j section 18.1.2.
 105              */
 106 #ifdef _MSC_VER
 107 #pragma inline_depth(0)
 108 #endif
 109             pthread_cleanup_push(ptw32_rwlock_cancelwrwait, (void*)rwl);
 110
 111             do
 112               {
 113                 result = pthread_cond_timedwait(&(rwl->cndSharedAccessCompleted),
 114                                                 &(rwl->mtxSharedAccessCompleted),
 115                                                 abstime);
 116               }
 117             while (result == 0 && rwl->nCompletedSharedAccessCount < 0);
 118
 119             pthread_cleanup_pop ((result != 0) ? 1 : 0);
 120 #ifdef _MSC_VER
 121 #pragma inline_depth()
 122 #endif
 123
 124             if (result == 0)
 125               {
 126                 rwl->nSharedAccessCount = 0;
 127               }
 128           }
 129       }
 130
 131     if (result == 0)
 132       {
 133         rwl->nExclusiveAccessCount++;
 134       }
 135
 136     return result;
 137 }