The Tor Browser / file diff

     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/ipc/glue/CrossProcessMutex_posix.cpp	Wed Dec 31 06:09:35 2014 +0100
     1.3 @@ -0,0 +1,131 @@
     1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
     1.5 + * This Source Code Form is subject to the terms of the Mozilla Public
     1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
     1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
     1.8 +
     1.9 +#include "CrossProcessMutex.h"
    1.10 +#include "mozilla/unused.h"
    1.11 +#include "nsDebug.h"
    1.12 +#include "nsISupportsImpl.h"
    1.13 +
    1.14 +namespace {
    1.15 +
    1.16 +struct MutexData {
    1.17 +  pthread_mutex_t mMutex;
    1.18 +  mozilla::Atomic<int32_t> mCount;
    1.19 +};
    1.20 +
    1.21 +}
    1.22 +
    1.23 +namespace mozilla {
    1.24 +
    1.25 +CrossProcessMutex::CrossProcessMutex(const char*)
    1.26 +    : mSharedBuffer(nullptr)
    1.27 +    , mMutex(nullptr)
    1.28 +    , mCount(nullptr)
    1.29 +{
    1.30 +  mSharedBuffer = new ipc::SharedMemoryBasic;
    1.31 +  if (!mSharedBuffer->Create(sizeof(MutexData))) {
    1.32 +    MOZ_CRASH();
    1.33 +  }
    1.34 +
    1.35 +  if (!mSharedBuffer->Map(sizeof(MutexData))) {
    1.36 +    MOZ_CRASH();
    1.37 +  }
    1.38 +
    1.39 +  MutexData* data = static_cast<MutexData*>(mSharedBuffer->memory());
    1.40 +
    1.41 +  if (!data) {
    1.42 +    MOZ_CRASH();
    1.43 +  }
    1.44 +
    1.45 +  mMutex = &(data->mMutex);
    1.46 +  mCount = &(data->mCount);
    1.47 +
    1.48 +  *mCount = 1;
    1.49 +
    1.50 +  pthread_mutexattr_t mutexAttributes;
    1.51 +  pthread_mutexattr_init(&mutexAttributes);
    1.52 +  // Make the mutex reentrant so it behaves the same as a win32 mutex
    1.53 +  if (pthread_mutexattr_settype(&mutexAttributes, PTHREAD_MUTEX_RECURSIVE)) {
    1.54 +    MOZ_CRASH();
    1.55 +  }
    1.56 +  if (pthread_mutexattr_setpshared(&mutexAttributes, PTHREAD_PROCESS_SHARED)) {
    1.57 +    MOZ_CRASH();
    1.58 +  }
    1.59 +
    1.60 +  if (pthread_mutex_init(mMutex, &mutexAttributes)) {
    1.61 +    MOZ_CRASH();
    1.62 +  }
    1.63 +
    1.64 +  MOZ_COUNT_CTOR(CrossProcessMutex);
    1.65 +}
    1.66 +
    1.67 +CrossProcessMutex::CrossProcessMutex(CrossProcessMutexHandle aHandle)
    1.68 +    : mSharedBuffer(nullptr)
    1.69 +    , mMutex(nullptr)
    1.70 +    , mCount(nullptr)
    1.71 +{
    1.72 +  if (!ipc::SharedMemoryBasic::IsHandleValid(aHandle)) {
    1.73 +    MOZ_CRASH();
    1.74 +  }
    1.75 +
    1.76 +  mSharedBuffer = new ipc::SharedMemoryBasic(aHandle);
    1.77 +
    1.78 +  if (!mSharedBuffer->Map(sizeof(MutexData))) {
    1.79 +    MOZ_CRASH();
    1.80 +  }
    1.81 +
    1.82 +  MutexData* data = static_cast<MutexData*>(mSharedBuffer->memory());
    1.83 +
    1.84 +  if (!data) {
    1.85 +    MOZ_CRASH();
    1.86 +  }
    1.87 +
    1.88 +  mMutex = &(data->mMutex);
    1.89 +  mCount = &(data->mCount);
    1.90 +  (*mCount)++;
    1.91 +
    1.92 +  MOZ_COUNT_CTOR(CrossProcessMutex);
    1.93 +}
    1.94 +
    1.95 +CrossProcessMutex::~CrossProcessMutex()
    1.96 +{
    1.97 +  int32_t count = --(*mCount);
    1.98 +
    1.99 +  if (count == 0) {
   1.100 +    // Nothing can be done if the destroy fails so ignore return code.
   1.101 +    unused << pthread_mutex_destroy(mMutex);
   1.102 +  }
   1.103 +
   1.104 +  delete mSharedBuffer;
   1.105 +  MOZ_COUNT_DTOR(CrossProcessMutex);
   1.106 +}
   1.107 +
   1.108 +void
   1.109 +CrossProcessMutex::Lock()
   1.110 +{
   1.111 +  MOZ_ASSERT(*mCount > 0, "Attempting to lock mutex with zero ref count");
   1.112 +  pthread_mutex_lock(mMutex);
   1.113 +}
   1.114 +
   1.115 +void
   1.116 +CrossProcessMutex::Unlock()
   1.117 +{
   1.118 +  MOZ_ASSERT(*mCount > 0, "Attempting to unlock mutex with zero ref count");
   1.119 +  pthread_mutex_unlock(mMutex);
   1.120 +}
   1.121 +
   1.122 +CrossProcessMutexHandle
   1.123 +CrossProcessMutex::ShareToProcess(base::ProcessHandle aHandle)
   1.124 +{
   1.125 +  CrossProcessMutexHandle result = ipc::SharedMemoryBasic::NULLHandle();
   1.126 +
   1.127 +  if (mSharedBuffer && !mSharedBuffer->ShareToProcess(aHandle, &result)) {
   1.128 +    MOZ_CRASH();
   1.129 +  }
   1.130 +
   1.131 +  return result;
   1.132 +}
   1.133 +
   1.134 +}