2406ce261c
Backed out changeset 8d9053f1c203 (bug 1942129) Backed out changeset 393e3c507c27 (bug 1942129) Backed out changeset 8240d353d224 (bug 1942129) Backed out changeset 8c4cd026b720 (bug 1942129) Backed out changeset 742634b0d6e9 (bug 1942129) Backed out changeset d16857f9812f (bug 1942129) Backed out changeset 7ff7af041ee7 (bug 1942129) Backed out changeset ef41d9e4c7de (bug 1942129)
141 lines
3.3 KiB
C++
141 lines
3.3 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::SharedMemory;
|
|
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::SharedMemory;
|
|
|
|
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::SharedMemory::NULLHandle();
|
|
|
|
if (mSharedBuffer) {
|
|
result = mSharedBuffer->CloneHandle();
|
|
if (!result) {
|
|
MOZ_CRASH();
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
} // namespace mozilla
|