service_runtime/nacl_interruptible_condvar.c

   1 /*
   2  * Copyright 2008, Google Inc.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met:
   8  *
   9  *     * Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  *     * Redistributions in binary form must reproduce the above
  12  * copyright notice, this list of conditions and the following disclaimer
  13  * in the documentation and/or other materials provided with the
  14  * distribution.
  15  *     * Neither the name of Google Inc. nor the names of its
  16  * contributors may be used to endorse or promote products derived from
  17  * this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  23  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * NaCl Server Runtime interruptible condvar, based on nacl_sync
  34  * interface.
  35  */
  36
  37 #include "native_client/include/portability.h"
  38 #include "native_client/service_runtime/nacl_interruptible_condvar.h"
  39
  40 #include "native_client/service_runtime/nacl_log.h"
  41 #include "native_client/service_runtime/nacl_sync_checked.h"
  42
  43 int NaClIntrCondVarCtor(struct NaClIntrCondVar  *cp)
  44 {
  45   return NaClCondVarCtor(&cp->cv);
  46 }
  47
  48
  49 void NaClIntrCondVarDtor(struct NaClIntrCondVar *cp)
  50 {
  51   NaClCondVarDtor(&cp->cv);
  52 }
  53
  54 NaClSyncStatus NaClIntrCondVarWait(struct NaClIntrCondVar         *cp,
  55                                    struct NaClIntrMutex           *mp,
  56                                    struct nacl_abi_timespec const *ts)
  57 {
  58   NaClSyncStatus rv = NACL_SYNC_INTERNAL_ERROR;
  59   NaClXMutexLock(&mp->mu);
  60
  61   if (NACL_INTR_LOCK_HELD != mp->lock_state) {
  62     if (NACL_INTR_LOCK_FREE == mp->lock_state) {
  63       /* NACL_INTR_LOCK_FREE - error - you must hold the lock */
  64       rv = NACL_SYNC_MUTEX_PERMISSION;
  65
  66     } else {
  67       /* NACL_INTR_LOCK_INTERRUPTED - just fail the request, we assume
  68        * that all objects are interrupted for the same reason
  69        */
  70       rv = NACL_SYNC_INTERNAL_ERROR;
  71     }
  72
  73     NaClXMutexUnlock(&mp->mu);
  74     return rv;
  75   }
  76
  77   mp->lock_state = NACL_INTR_LOCK_FREE;
  78   NaClXCondVarSignal(&mp->cv);
  79   /* wait on the internal condvar according to the call type */
  80   if (NULL == ts) {
  81     rv = NaClCondVarWait(&cp->cv, &mp->mu);
  82   } else {
  83     rv = NaClCondVarTimedWaitAbsolute(&cp->cv, &mp->mu, ts);
  84   }
  85
  86   /* When we get here we own mp->mu again
  87    * so we need to take mp as in its implementation
  88    */
  89   while ((NACL_SYNC_CONDVAR_TIMEDOUT != rv) &&
  90       (NACL_INTR_LOCK_HELD == mp->lock_state)) {
  91     if (NULL == ts) {
  92        rv = NaClCondVarWait(&mp->cv, &mp->mu);
  93     } else {
  94       rv = NaClCondVarTimedWaitAbsolute(&mp->cv, &mp->mu, ts);
  95     }
  96   }
  97   if (NACL_INTR_LOCK_FREE == mp->lock_state) {
  98     mp->lock_state = NACL_INTR_LOCK_HELD;
  99     rv = NACL_SYNC_OK;
 100   }
 101   NaClXMutexUnlock(&mp->mu);
 102   return rv;
 103 }
 104
 105 NaClSyncStatus NaClIntrCondVarSignal(struct NaClIntrCondVar *cp)
 106 {
 107   return NaClCondVarSignal(&cp->cv);
 108 }
 109
 110 NaClSyncStatus NaClIntrCondVarBroadcast(struct NaClIntrCondVar *cp)
 111 {
 112   return NaClCondVarBroadcast(&cp->cv);
 113 }
 114
 115 void NaClIntrCondVarIntr(struct NaClIntrCondVar *cp)
 116 {
 117   /* NOTE: we assume that mutexes are interrupted first,
 118    * so we will fail to regain ownership of the mutex once
 119    * the wait for cp->cv is completed (see NaClIntrCondVarWait above) */
 120   NaClCondVarBroadcast(&cp->cv);
 121 }
 122
 123 void NaClIntrCondVarReset(struct NaClIntrCondVar *cp)
 124 {
 125   /* nothing to do here - we don't keep status */
 126   return;
 127 }