зеркало из https://github.com/mozilla/gecko-dev.git
141 строка
3.4 KiB
C++
141 строка
3.4 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
|
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#include "CrossProcessMutex.h"
|
|
#include "mozilla/Unused.h"
|
|
#include "nsDebug.h"
|
|
#include "nsISupportsImpl.h"
|
|
|
|
namespace {
|
|
|
|
struct MutexData {
|
|
pthread_mutex_t mMutex;
|
|
mozilla::Atomic<int32_t> mCount;
|
|
};
|
|
|
|
} // namespace
|
|
|
|
namespace mozilla {
|
|
|
|
static void InitMutex(pthread_mutex_t* mMutex) {
|
|
pthread_mutexattr_t mutexAttributes;
|
|
pthread_mutexattr_init(&mutexAttributes);
|
|
// Make the mutex reentrant so it behaves the same as a win32 mutex
|
|
if (pthread_mutexattr_settype(&mutexAttributes, PTHREAD_MUTEX_RECURSIVE)) {
|
|
MOZ_CRASH();
|
|
}
|
|
if (pthread_mutexattr_setpshared(&mutexAttributes, PTHREAD_PROCESS_SHARED)) {
|
|
MOZ_CRASH();
|
|
}
|
|
|
|
if (pthread_mutex_init(mMutex, &mutexAttributes)) {
|
|
MOZ_CRASH();
|
|
}
|
|
}
|
|
|
|
CrossProcessMutex::CrossProcessMutex(const char*)
|
|
: mMutex(nullptr), mCount(nullptr) {
|
|
#if defined(MOZ_SANDBOX)
|
|
// POSIX mutexes in shared memory aren't guaranteed to be safe - and
|
|
// they specifically are not on Linux.
|
|
MOZ_RELEASE_ASSERT(false);
|
|
#endif
|
|
mSharedBuffer = new ipc::SharedMemoryBasic;
|
|
if (!mSharedBuffer->Create(sizeof(MutexData))) {
|
|
MOZ_CRASH();
|
|
}
|
|
|
|
if (!mSharedBuffer->Map(sizeof(MutexData))) {
|
|
MOZ_CRASH();
|
|
}
|
|
|
|
MutexData* data = static_cast<MutexData*>(mSharedBuffer->memory());
|
|
|
|
if (!data) {
|
|
MOZ_CRASH();
|
|
}
|
|
|
|
mMutex = &(data->mMutex);
|
|
mCount = &(data->mCount);
|
|
|
|
*mCount = 1;
|
|
InitMutex(mMutex);
|
|
|
|
MOZ_COUNT_CTOR(CrossProcessMutex);
|
|
}
|
|
|
|
CrossProcessMutex::CrossProcessMutex(CrossProcessMutexHandle aHandle)
|
|
: mMutex(nullptr), mCount(nullptr) {
|
|
mSharedBuffer = new ipc::SharedMemoryBasic;
|
|
|
|
if (!mSharedBuffer->IsHandleValid(aHandle)) {
|
|
MOZ_CRASH();
|
|
}
|
|
|
|
if (!mSharedBuffer->SetHandle(std::move(aHandle),
|
|
ipc::SharedMemory::RightsReadWrite)) {
|
|
MOZ_CRASH();
|
|
}
|
|
|
|
if (!mSharedBuffer->Map(sizeof(MutexData))) {
|
|
MOZ_CRASH();
|
|
}
|
|
|
|
MutexData* data = static_cast<MutexData*>(mSharedBuffer->memory());
|
|
|
|
if (!data) {
|
|
MOZ_CRASH();
|
|
}
|
|
|
|
mMutex = &(data->mMutex);
|
|
mCount = &(data->mCount);
|
|
int32_t count = (*mCount)++;
|
|
|
|
if (count == 0) {
|
|
// The other side has already let go of their CrossProcessMutex, so now
|
|
// mMutex is garbage. We need to re-initialize it.
|
|
InitMutex(mMutex);
|
|
}
|
|
|
|
MOZ_COUNT_CTOR(CrossProcessMutex);
|
|
}
|
|
|
|
CrossProcessMutex::~CrossProcessMutex() {
|
|
int32_t count = --(*mCount);
|
|
|
|
if (count == 0) {
|
|
// Nothing can be done if the destroy fails so ignore return code.
|
|
Unused << pthread_mutex_destroy(mMutex);
|
|
}
|
|
|
|
MOZ_COUNT_DTOR(CrossProcessMutex);
|
|
}
|
|
|
|
void CrossProcessMutex::Lock() {
|
|
MOZ_ASSERT(*mCount > 0, "Attempting to lock mutex with zero ref count");
|
|
pthread_mutex_lock(mMutex);
|
|
}
|
|
|
|
void CrossProcessMutex::Unlock() {
|
|
MOZ_ASSERT(*mCount > 0, "Attempting to unlock mutex with zero ref count");
|
|
pthread_mutex_unlock(mMutex);
|
|
}
|
|
|
|
CrossProcessMutexHandle CrossProcessMutex::CloneHandle() {
|
|
CrossProcessMutexHandle result = ipc::SharedMemoryBasic::NULLHandle();
|
|
|
|
if (mSharedBuffer) {
|
|
result = mSharedBuffer->CloneHandle();
|
|
if (!result) {
|
|
MOZ_CRASH();
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
} // namespace mozilla
|