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/* -*- 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,
#include "BackgroundChild.h"
#include "BackgroundParent.h"
#include "BackgroundChildImpl.h"
#include "BackgroundParentImpl.h"
#include "MainThreadUtils.h"
#include "base/process_util.h"
#include "base/task.h"
#include "FileDescriptor.h"
#include "GeckoProfiler.h"
#include "InputStreamUtils.h"
#include "mozilla/Assertions.h"
#include "mozilla/Atomics.h"
#include "mozilla/ClearOnShutdown.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/MozPromise.h"
#include "mozilla/Services.h"
#include "mozilla/SpinEventLoopUntil.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/Unused.h"
#include "mozilla/dom/ContentChild.h"
#include "mozilla/dom/ContentParent.h"
#include "mozilla/dom/File.h"
#include "mozilla/dom/WorkerPrivate.h"
#include "mozilla/dom/WorkerRef.h"
#include "mozilla/ipc/BackgroundStarterChild.h"
#include "mozilla/ipc/BackgroundStarterParent.h"
#include "mozilla/ipc/Endpoint.h"
#include "mozilla/ipc/PBackgroundStarter.h"
#include "mozilla/ipc/ProtocolTypes.h"
#include "nsCOMPtr.h"
#include "nsIEventTarget.h"
#include "nsIObserver.h"
#include "nsIObserverService.h"
#include "nsIRunnable.h"
#include "nsISupportsImpl.h"
#include "nsIThread.h"
#include "nsITimer.h"
#include "nsTArray.h"
#include "nsThreadUtils.h"
#include "nsTraceRefcnt.h"
#include "nsXULAppAPI.h"
#include "nsXPCOMPrivate.h"
#include "prthread.h"
#include <functional>
#ifdef RELEASE_OR_BETA
# define THREADSAFETY_ASSERT MOZ_ASSERT
#else
# define THREADSAFETY_ASSERT MOZ_RELEASE_ASSERT
#endif
#define CRASH_IN_CHILD_PROCESS(_msg) \
do { \
if (XRE_IsParentProcess()) { \
MOZ_ASSERT(false, _msg); \
} else { \
MOZ_CRASH(_msg); \
} \
} while (0)
using namespace mozilla;
using namespace mozilla::dom;
using namespace mozilla::ipc;
using namespace mozilla::net;
namespace {
// This exists so that [Assert]IsOnBackgroundThread() can continue to work
// during shutdown. We can rely on TLS being 0 initialized, so only the
// background thread itself needs to ever set this flag.
static MOZ_THREAD_LOCAL(bool) sTLSIsOnBackgroundThread;
class ChildImpl;
// -----------------------------------------------------------------------------
// Utility Functions
// -----------------------------------------------------------------------------
void AssertIsOnMainThread() { THREADSAFETY_ASSERT(NS_IsMainThread()); }
// -----------------------------------------------------------------------------
// ParentImpl Declaration
// -----------------------------------------------------------------------------
class ParentImpl final : public BackgroundParentImpl {
friend class ChildImpl;
friend class mozilla::ipc::BackgroundParent;
friend class mozilla::ipc::BackgroundStarterParent;
private:
class ShutdownObserver;
struct MOZ_STACK_CLASS TimerCallbackClosure {
nsIThread* mThread;
nsTArray<IToplevelProtocol*>* mLiveActors;
TimerCallbackClosure(nsIThread* aThread,
nsTArray<IToplevelProtocol*>* aLiveActors)
: mThread(aThread), mLiveActors(aLiveActors) {
AssertIsInMainProcess();
AssertIsOnMainThread();
MOZ_ASSERT(aThread);
MOZ_ASSERT(aLiveActors);
}
};
// The length of time we will wait at shutdown for all actors to clean
// themselves up before forcing them to be destroyed.
static const uint32_t kShutdownTimerDelayMS = 10000;
// This is only modified on the main thread. It is null if the thread does not
// exist or is shutting down.
static StaticRefPtr<nsIThread> sBackgroundThread;
// This is created and destroyed on the main thread but only modified on the
// background thread. It is specific to each instance of sBackgroundThread.
static nsTArray<IToplevelProtocol*>* sLiveActorsForBackgroundThread;
// This is only modified on the main thread.
static StaticRefPtr<nsITimer> sShutdownTimer;
// Maintains a count of live actors so that the background thread can be shut
// down when it is no longer needed.
// May be incremented on either the background thread (by an existing actor)
// or on the main thread, but must be decremented on the main thread.
static Atomic<uint64_t> sLiveActorCount;
// This is only modified on the main thread. It is true after the shutdown
// observer is registered and is never unset thereafter.
static bool sShutdownObserverRegistered;
// This is only modified on the main thread. It prevents us from trying to
// create the background thread after application shutdown has started.
static bool sShutdownHasStarted;
// null if this is a same-process actor.
const RefPtr<ThreadsafeContentParentHandle> mContent;
// Set when the actor is opened successfully and used to handle shutdown
// hangs. Only touched on the background thread.
nsTArray<IToplevelProtocol*>* mLiveActorArray;
// Set at construction to indicate whether this parent actor corresponds to a
// child actor in another process or to a child actor from a different thread
// in the same process.
const bool mIsOtherProcessActor;
// Set after ActorDestroy has been called. Only touched on the background
// thread.
bool mActorDestroyed;
public:
static already_AddRefed<nsISerialEventTarget> GetBackgroundThread() {
AssertIsInMainProcess();
THREADSAFETY_ASSERT(NS_IsMainThread() || IsOnBackgroundThread());
return do_AddRef(sBackgroundThread);
}
static bool IsOnBackgroundThread() {
MOZ_ASSERT(sTLSIsOnBackgroundThread.initialized());
return sTLSIsOnBackgroundThread.get();
}
static void AssertIsOnBackgroundThread() {
THREADSAFETY_ASSERT(IsOnBackgroundThread());
}
// `ParentImpl` instances need to be deleted on the main thread, despite IPC
// controlling them on a background thread. Use `_WITH_DELETE_ON_MAIN_THREAD`
// to force destruction to occur on the desired thread.
NS_INLINE_DECL_THREADSAFE_REFCOUNTING_WITH_DELETE_ON_MAIN_THREAD(ParentImpl,
override)
void Destroy();
private:
// Forwarded from BackgroundParent.
static bool IsOtherProcessActor(PBackgroundParent* aBackgroundActor);
// Forwarded from BackgroundParent.
static ThreadsafeContentParentHandle* GetContentParentHandle(
PBackgroundParent* aBackgroundActor);
// Forwarded from BackgroundParent.
static uint64_t GetChildID(PBackgroundParent* aBackgroundActor);
// Forwarded from BackgroundParent.
static void KillHardAsync(PBackgroundParent* aBackgroundActor,
const nsACString& aReason);
// Forwarded from BackgroundParent.
static bool AllocStarter(ContentParent* aContent,
Endpoint<PBackgroundStarterParent>&& aEndpoint,
bool aCrossProcess = true);
static bool CreateBackgroundThread();
static void ShutdownBackgroundThread();
static void ShutdownTimerCallback(nsITimer* aTimer, void* aClosure);
// NOTE: ParentImpl could be used in 2 cases below.
// 1. Within the parent process.
// 2. Between parent process and content process.
// |aContent| should be not null for case 2. For cases 1, it's null.
explicit ParentImpl(ThreadsafeContentParentHandle* aContent,
bool aIsOtherProcessActor)
: mContent(aContent),
mLiveActorArray(nullptr),
mIsOtherProcessActor(aIsOtherProcessActor),
mActorDestroyed(false) {
AssertIsInMainProcess();
MOZ_ASSERT_IF(!aIsOtherProcessActor, XRE_IsParentProcess());
}
~ParentImpl() {
AssertIsInMainProcess();
AssertIsOnMainThread();
}
void MainThreadActorDestroy();
void SetLiveActorArray(nsTArray<IToplevelProtocol*>* aLiveActorArray) {
AssertIsInMainProcess();
AssertIsOnBackgroundThread();
MOZ_ASSERT(aLiveActorArray);
MOZ_ASSERT(!aLiveActorArray->Contains(this));
MOZ_ASSERT(!mLiveActorArray);
MOZ_ASSERT(mIsOtherProcessActor);
mLiveActorArray = aLiveActorArray;
mLiveActorArray->AppendElement(this);
}
// These methods are only called by IPDL.
virtual void ActorDestroy(ActorDestroyReason aWhy) override;
};
// -----------------------------------------------------------------------------
// ChildImpl Declaration
// -----------------------------------------------------------------------------
class ChildImpl final : public BackgroundChildImpl {
friend class mozilla::ipc::BackgroundChild;
friend class mozilla::ipc::BackgroundChildImpl;
friend class mozilla::ipc::BackgroundStarterChild;
typedef base::ProcessId ProcessId;
class ShutdownObserver;
public:
struct ThreadLocalInfo {
ThreadLocalInfo()
#ifdef DEBUG
: mClosed(false)
#endif
{
}
RefPtr<ChildImpl> mActor;
UniquePtr<BackgroundChildImpl::ThreadLocal> mConsumerThreadLocal;
#ifdef DEBUG
bool mClosed;
#endif
};
private:
// A thread-local index that is not valid.
static constexpr unsigned int kBadThreadLocalIndex =
static_cast<unsigned int>(-1);
// ThreadInfoWrapper encapsulates ThreadLocalInfo and ThreadLocalIndex and
// also provides some common functions for creating PBackground IPC actor.
class ThreadInfoWrapper final {
friend class ChildImpl;
public:
using ActorCreateFunc = void (*)(ThreadLocalInfo*, unsigned int,
nsIEventTarget*, ChildImpl**);
ThreadInfoWrapper() = default;
void Startup() {
MOZ_ASSERT(mThreadLocalIndex == kBadThreadLocalIndex,
"ThreadInfoWrapper::Startup() called more than once!");
PRStatus status =
PR_NewThreadPrivateIndex(&mThreadLocalIndex, ThreadLocalDestructor);
MOZ_RELEASE_ASSERT(status == PR_SUCCESS,
"PR_NewThreadPrivateIndex failed!");
MOZ_ASSERT(mThreadLocalIndex != kBadThreadLocalIndex);
}
void Shutdown() {
if (sShutdownHasStarted) {
MOZ_ASSERT_IF(mThreadLocalIndex != kBadThreadLocalIndex,
!PR_GetThreadPrivate(mThreadLocalIndex));
return;
}
if (mThreadLocalIndex == kBadThreadLocalIndex) {
return;
}
RefPtr<BackgroundStarterChild> starter;
{
auto lock = mStarter.Lock();
starter = lock->forget();
}
if (starter) {
CloseStarter(starter);
}
ThreadLocalInfo* threadLocalInfo;
#ifdef DEBUG
threadLocalInfo =
static_cast<ThreadLocalInfo*>(PR_GetThreadPrivate(mThreadLocalIndex));
MOZ_ASSERT(!threadLocalInfo);
#endif
threadLocalInfo = mMainThreadInfo;
if (threadLocalInfo) {
#ifdef DEBUG
MOZ_ASSERT(!threadLocalInfo->mClosed);
threadLocalInfo->mClosed = true;
#endif
ThreadLocalDestructor(threadLocalInfo);
mMainThreadInfo = nullptr;
}
}
template <typename Actor>
void InitStarter(Actor* aActor) {
AssertIsOnMainThread();
// Create a pair of endpoints and send them to the other process.
Endpoint<PBackgroundStarterParent> parent;
Endpoint<PBackgroundStarterChild> child;
MOZ_ALWAYS_SUCCEEDS(PBackgroundStarter::CreateEndpoints(
aActor->OtherEndpointProcInfo(), EndpointProcInfo::Current(), &parent,
&child));
MOZ_ALWAYS_TRUE(aActor->SendInitBackground(std::move(parent)));
InitStarter(std::move(child));
}
void InitStarter(Endpoint<PBackgroundStarterChild>&& aEndpoint) {
AssertIsOnMainThread();
EndpointProcInfo otherProcInfo = aEndpoint.OtherEndpointProcInfo();
nsCOMPtr<nsISerialEventTarget> taskQueue;
MOZ_ALWAYS_SUCCEEDS(NS_CreateBackgroundTaskQueue(
"PBackgroundStarter Queue", getter_AddRefs(taskQueue)));
RefPtr<BackgroundStarterChild> starter =
new BackgroundStarterChild(otherProcInfo, taskQueue);
taskQueue->Dispatch(NS_NewRunnableFunction(
"PBackgroundStarterChild Init",
[starter, endpoint = std::move(aEndpoint)]() mutable {
MOZ_ALWAYS_TRUE(endpoint.Bind(starter));
}));
// Swap in the newly initialized `BackgroundStarterChild`, and close the
// previous one if we're replacing an existing PBackgroundStarterChild
// instance.
RefPtr<BackgroundStarterChild> prevStarter;
{
auto lock = mStarter.Lock();
prevStarter = lock->forget();
*lock = starter.forget();
}
if (prevStarter) {
CloseStarter(prevStarter);
}
}
void CloseForCurrentThread() {
MOZ_ASSERT(!NS_IsMainThread());
if (mThreadLocalIndex == kBadThreadLocalIndex) {
return;
}
auto* threadLocalInfo =
static_cast<ThreadLocalInfo*>(PR_GetThreadPrivate(mThreadLocalIndex));
if (!threadLocalInfo) {
return;
}
#ifdef DEBUG
MOZ_ASSERT(!threadLocalInfo->mClosed);
threadLocalInfo->mClosed = true;
#endif
// Clearing the thread local will synchronously close the actor.
DebugOnly<PRStatus> status =
PR_SetThreadPrivate(mThreadLocalIndex, nullptr);
MOZ_ASSERT(status == PR_SUCCESS);
}
PBackgroundChild* GetOrCreateForCurrentThread() {
// Processes can be told to do final CC's during shutdown even though
// they never finished starting (and thus call this), because they
// hadn't gotten far enough to call Startup() before shutdown began.
if (mThreadLocalIndex == kBadThreadLocalIndex) {
NS_ERROR("BackgroundChild::Startup() was never called");
return nullptr;
}
if (NS_IsMainThread() && ChildImpl::sShutdownHasStarted) {
return nullptr;
}
auto* threadLocalInfo = NS_IsMainThread()
? mMainThreadInfo
: static_cast<ThreadLocalInfo*>(
PR_GetThreadPrivate(mThreadLocalIndex));
if (!threadLocalInfo) {
auto newInfo = MakeUnique<ThreadLocalInfo>();
if (NS_IsMainThread()) {
mMainThreadInfo = newInfo.get();
} else {
if (PR_SetThreadPrivate(mThreadLocalIndex, newInfo.get()) !=
PR_SUCCESS) {
CRASH_IN_CHILD_PROCESS("PR_SetThreadPrivate failed!");
return nullptr;
}
}
threadLocalInfo = newInfo.release();
}
if (threadLocalInfo->mActor) {
return threadLocalInfo->mActor;
}
RefPtr<BackgroundStarterChild> starter;
{
auto lock = mStarter.Lock();
starter = *lock;
}
if (!starter) {
CRASH_IN_CHILD_PROCESS("No BackgroundStarterChild");
return nullptr;
}
Endpoint<PBackgroundParent> parent;
Endpoint<PBackgroundChild> child;
nsresult rv;
rv = PBackground::CreateEndpoints(starter->mOtherProcInfo,
EndpointProcInfo::Current(), &parent,
&child);
if (NS_FAILED(rv)) {
NS_WARNING("Failed to create top level actor!");
return nullptr;
}
RefPtr<ChildImpl> strongActor = new ChildImpl();
if (!child.Bind(strongActor)) {
CRASH_IN_CHILD_PROCESS("Failed to bind ChildImpl!");
return nullptr;
}
strongActor->SetActorAlive();
threadLocalInfo->mActor = strongActor;
// Dispatch to the background task queue to create the relevant actor in
// the remote process.
starter->mTaskQueue->Dispatch(NS_NewRunnableFunction(
"PBackground GetOrCreateForCurrentThread",
[starter, endpoint = std::move(parent)]() mutable {
if (!starter->SendInitBackground(std::move(endpoint))) {
NS_WARNING("Failed to create toplevel actor");
}
}));
return strongActor;
}
private:
static void CloseStarter(BackgroundStarterChild* aStarter) {
aStarter->mTaskQueue->Dispatch(NS_NewRunnableFunction(
"PBackgroundStarterChild Close",
[starter = RefPtr{aStarter}] { starter->Close(); }));
}
// This is only modified on the main thread. It is the thread-local index
// that we use to store the BackgroundChild for each thread.
unsigned int mThreadLocalIndex = kBadThreadLocalIndex;
// On the main thread, we store TLS in this global instead of in
// mThreadLocalIndex. That way, cooperative main threads all share the same
// thread info.
ThreadLocalInfo* mMainThreadInfo = nullptr;
// The starter which will be used to launch PBackground instances of this
// type. Only modified on the main thread, but may be read by any thread
// wanting to start background actors.
StaticDataMutex<StaticRefPtr<BackgroundStarterChild>> mStarter{"mStarter"};
};
// For PBackground between parent and content process.
static ThreadInfoWrapper sParentAndContentProcessThreadInfo;
// This is only modified on the main thread. It prevents us from trying to
// create the background thread after application shutdown has started.
static bool sShutdownHasStarted;
#if defined(DEBUG) || !defined(RELEASE_OR_BETA)
nsISerialEventTarget* mOwningEventTarget;
#endif
#ifdef DEBUG
bool mActorWasAlive;
bool mActorDestroyed;
#endif
public:
static void Shutdown();
void AssertIsOnOwningThread() {
THREADSAFETY_ASSERT(mOwningEventTarget);
#ifdef RELEASE_OR_BETA
DebugOnly<bool> current;
#else
bool current;
#endif
THREADSAFETY_ASSERT(
NS_SUCCEEDED(mOwningEventTarget->IsOnCurrentThread(¤t)));
THREADSAFETY_ASSERT(current);
}
void AssertActorDestroyed() {
MOZ_ASSERT(mActorDestroyed, "ChildImpl::ActorDestroy not called in time");
}
explicit ChildImpl()
#if defined(DEBUG) || !defined(RELEASE_OR_BETA)
: mOwningEventTarget(GetCurrentSerialEventTarget())
#endif
#ifdef DEBUG
,
mActorWasAlive(false),
mActorDestroyed(false)
#endif
{
AssertIsOnOwningThread();
}
void SetActorAlive() {
AssertIsOnOwningThread();
MOZ_ASSERT(!mActorWasAlive);
MOZ_ASSERT(!mActorDestroyed);
#ifdef DEBUG
mActorWasAlive = true;
#endif
}
// This type is threadsafe refcounted as actors managed by it may be destroyed
// after the thread it is bound to dies, and hold a reference to this object.
//
// It is _not_ safe to use this type or any methods on it from off of the
// thread it was created for.
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ChildImpl, override)
private:
// Forwarded from BackgroundChild.
static void Startup();
// Forwarded from BackgroundChild.
static PBackgroundChild* GetForCurrentThread();
// Forwarded from BackgroundChild.
static PBackgroundChild* GetOrCreateForCurrentThread();
static void CloseForCurrentThread();
// Forwarded from BackgroundChildImpl.
static BackgroundChildImpl::ThreadLocal* GetThreadLocalForCurrentThread();
// Forwarded from BackgroundChild.
static void InitContentStarter(mozilla::dom::ContentChild* aContent);
static void ThreadLocalDestructor(void* aThreadLocal);
// This class is reference counted.
~ChildImpl() { MOZ_ASSERT_IF(mActorWasAlive, mActorDestroyed); }
// Only called by IPDL.
virtual void ActorDestroy(ActorDestroyReason aWhy) override;
};
// -----------------------------------------------------------------------------
// ParentImpl Helper Declarations
// -----------------------------------------------------------------------------
class ParentImpl::ShutdownObserver final : public nsIObserver {
public:
ShutdownObserver() { AssertIsOnMainThread(); }
NS_DECL_ISUPPORTS
NS_DECL_NSIOBSERVER
private:
~ShutdownObserver() { AssertIsOnMainThread(); }
};
// -----------------------------------------------------------------------------
// ChildImpl Helper Declarations
// -----------------------------------------------------------------------------
class ChildImpl::ShutdownObserver final : public nsIObserver {
public:
ShutdownObserver() { AssertIsOnMainThread(); }
NS_DECL_ISUPPORTS
NS_DECL_NSIOBSERVER
private:
~ShutdownObserver() { AssertIsOnMainThread(); }
};
} // namespace
namespace mozilla {
namespace ipc {
bool IsOnBackgroundThread() { return ParentImpl::IsOnBackgroundThread(); }
#ifdef DEBUG
void AssertIsOnBackgroundThread() { ParentImpl::AssertIsOnBackgroundThread(); }
#endif // DEBUG
} // namespace ipc
} // namespace mozilla
// -----------------------------------------------------------------------------
// BackgroundParent Public Methods
// -----------------------------------------------------------------------------
// static
already_AddRefed<nsISerialEventTarget> BackgroundParent::GetBackgroundThread() {
return ParentImpl::GetBackgroundThread();
}
// static
bool BackgroundParent::IsOtherProcessActor(
PBackgroundParent* aBackgroundActor) {
return ParentImpl::IsOtherProcessActor(aBackgroundActor);
}
// static
ThreadsafeContentParentHandle* BackgroundParent::GetContentParentHandle(
PBackgroundParent* aBackgroundActor) {
return ParentImpl::GetContentParentHandle(aBackgroundActor);
}
// static
uint64_t BackgroundParent::GetChildID(PBackgroundParent* aBackgroundActor) {
return ParentImpl::GetChildID(aBackgroundActor);
}
// static
void BackgroundParent::KillHardAsync(PBackgroundParent* aBackgroundActor,
const nsACString& aReason) {
ParentImpl::KillHardAsync(aBackgroundActor, aReason);
}
// static
bool BackgroundParent::AllocStarter(
ContentParent* aContent, Endpoint<PBackgroundStarterParent>&& aEndpoint) {
return ParentImpl::AllocStarter(aContent, std::move(aEndpoint));
}
// -----------------------------------------------------------------------------
// BackgroundChild Public Methods
// -----------------------------------------------------------------------------
// static
void BackgroundChild::Startup() { ChildImpl::Startup(); }
// static
PBackgroundChild* BackgroundChild::GetForCurrentThread() {
return ChildImpl::GetForCurrentThread();
}
// static
PBackgroundChild* BackgroundChild::GetOrCreateForCurrentThread() {
return ChildImpl::GetOrCreateForCurrentThread();
}
// static
void BackgroundChild::CloseForCurrentThread() {
ChildImpl::CloseForCurrentThread();
}
// static
void BackgroundChild::InitContentStarter(ContentChild* aContent) {
ChildImpl::InitContentStarter(aContent);
}
// -----------------------------------------------------------------------------
// BackgroundChildImpl Public Methods
// -----------------------------------------------------------------------------
// static
BackgroundChildImpl::ThreadLocal*
BackgroundChildImpl::GetThreadLocalForCurrentThread() {
return ChildImpl::GetThreadLocalForCurrentThread();
}
// -----------------------------------------------------------------------------
// ParentImpl Static Members
// -----------------------------------------------------------------------------
StaticRefPtr<nsIThread> ParentImpl::sBackgroundThread;
nsTArray<IToplevelProtocol*>* ParentImpl::sLiveActorsForBackgroundThread;
StaticRefPtr<nsITimer> ParentImpl::sShutdownTimer;
Atomic<uint64_t> ParentImpl::sLiveActorCount;
bool ParentImpl::sShutdownObserverRegistered = false;
bool ParentImpl::sShutdownHasStarted = false;
// -----------------------------------------------------------------------------
// ChildImpl Static Members
// -----------------------------------------------------------------------------
MOZ_RUNINIT ChildImpl::ThreadInfoWrapper
ChildImpl::sParentAndContentProcessThreadInfo;
bool ChildImpl::sShutdownHasStarted = false;
// -----------------------------------------------------------------------------
// ParentImpl Implementation
// -----------------------------------------------------------------------------
// static
bool ParentImpl::IsOtherProcessActor(PBackgroundParent* aBackgroundActor) {
AssertIsOnBackgroundThread();
MOZ_ASSERT(aBackgroundActor);
return static_cast<ParentImpl*>(aBackgroundActor)->mIsOtherProcessActor;
}
// static
ThreadsafeContentParentHandle* ParentImpl::GetContentParentHandle(
PBackgroundParent* aBackgroundActor) {
AssertIsOnBackgroundThread();
MOZ_ASSERT(aBackgroundActor);
return static_cast<ParentImpl*>(aBackgroundActor)->mContent.get();
}
// static
uint64_t ParentImpl::GetChildID(PBackgroundParent* aBackgroundActor) {
AssertIsOnBackgroundThread();
MOZ_ASSERT(aBackgroundActor);
auto actor = static_cast<ParentImpl*>(aBackgroundActor);
if (actor->mContent) {
return actor->mContent->ChildID();
}
return 0;
}
// static
void ParentImpl::KillHardAsync(PBackgroundParent* aBackgroundActor,
const nsACString& aReason) {
AssertIsInMainProcess();
AssertIsOnBackgroundThread();
MOZ_ASSERT(aBackgroundActor);
MOZ_ASSERT(BackgroundParent::IsOtherProcessActor(aBackgroundActor));
RefPtr<ThreadsafeContentParentHandle> handle =
GetContentParentHandle(aBackgroundActor);
MOZ_ASSERT(handle);
MOZ_ALWAYS_SUCCEEDS(NS_DispatchToMainThread(
NS_NewRunnableFunction(
"ParentImpl::KillHardAsync",
[handle = std::move(handle), reason = nsCString{aReason}]() {
mozilla::AssertIsOnMainThread();
if (RefPtr<ContentParent> contentParent =
handle->GetContentParent()) {
contentParent->KillHard(reason.get());
}
}),
NS_DISPATCH_NORMAL));
// After we've scheduled killing of the remote process, also ensure we induce
// a connection error in the IPC channel to immediately stop all IPC
// communication on this channel.
if (aBackgroundActor->CanSend()) {
aBackgroundActor->GetIPCChannel()->InduceConnectionError();
}
}
// static
bool ParentImpl::AllocStarter(ContentParent* aContent,
Endpoint<PBackgroundStarterParent>&& aEndpoint,
bool aCrossProcess) {
AssertIsInMainProcess();
AssertIsOnMainThread();
MOZ_ASSERT(aEndpoint.IsValid());
if (!sBackgroundThread && !CreateBackgroundThread()) {
NS_WARNING("Failed to create background thread!");
return false;
}
sLiveActorCount++;
RefPtr<BackgroundStarterParent> actor = new BackgroundStarterParent(
aContent ? aContent->ThreadsafeHandle() : nullptr, aCrossProcess);
if (NS_FAILED(sBackgroundThread->Dispatch(NS_NewRunnableFunction(
"BackgroundStarterParent::ConnectActorRunnable",
[actor = std::move(actor), endpoint = std::move(aEndpoint),
liveActorArray = sLiveActorsForBackgroundThread]() mutable {
MOZ_ASSERT(endpoint.IsValid());
MOZ_ALWAYS_TRUE(endpoint.Bind(actor));
actor->SetLiveActorArray(liveActorArray);
})))) {
NS_WARNING("Failed to dispatch connect runnable!");
MOZ_ASSERT(sLiveActorCount);
sLiveActorCount--;
}
return true;
}
// static
bool ParentImpl::CreateBackgroundThread() {
AssertIsInMainProcess();
AssertIsOnMainThread();
MOZ_ASSERT(!sBackgroundThread);
MOZ_ASSERT(!sLiveActorsForBackgroundThread);
if (sShutdownHasStarted) {
NS_WARNING(
"Trying to create background thread after shutdown has "
"already begun!");
return false;
}
nsCOMPtr<nsITimer> newShutdownTimer;
if (!sShutdownTimer) {
newShutdownTimer = NS_NewTimer();
if (!newShutdownTimer) {
return false;
}
}
if (!sShutdownObserverRegistered) {
nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
if (NS_WARN_IF(!obs)) {
return false;
}
nsCOMPtr<nsIObserver> observer = new ShutdownObserver();
nsresult rv = obs->AddObserver(
observer, NS_XPCOM_SHUTDOWN_THREADS_OBSERVER_ID, false);
if (NS_WARN_IF(NS_FAILED(rv))) {
return false;
}
sShutdownObserverRegistered = true;
}
nsCOMPtr<nsIThread> thread;
if (NS_FAILED(NS_NewNamedThread(
"IPDL Background", getter_AddRefs(thread),
NS_NewRunnableFunction(
"Background::ParentImpl::CreateBackgroundThreadRunnable", []() {
MOZ_ASSERT(sTLSIsOnBackgroundThread.initialized());
sTLSIsOnBackgroundThread.set(true);
})))) {
NS_WARNING("NS_NewNamedThread failed!");
return false;
}
sBackgroundThread = thread.forget();
sLiveActorsForBackgroundThread = new nsTArray<IToplevelProtocol*>(1);
if (!sShutdownTimer) {
MOZ_ASSERT(newShutdownTimer);
sShutdownTimer = newShutdownTimer;
}
return true;
}
// static
void ParentImpl::ShutdownBackgroundThread() {
AssertIsInMainProcess();
AssertIsOnMainThread();
MOZ_ASSERT(sShutdownHasStarted);
MOZ_ASSERT_IF(!sBackgroundThread, !sLiveActorCount);
MOZ_ASSERT_IF(sBackgroundThread, sShutdownTimer);
nsCOMPtr<nsITimer> shutdownTimer = sShutdownTimer.get();
sShutdownTimer = nullptr;
if (sBackgroundThread) {
nsCOMPtr<nsIThread> thread = sBackgroundThread.get();
sBackgroundThread = nullptr;
UniquePtr<nsTArray<IToplevelProtocol*>> liveActors(
sLiveActorsForBackgroundThread);
sLiveActorsForBackgroundThread = nullptr;
MOZ_ASSERT_IF(!sShutdownHasStarted, !sLiveActorCount);
if (sLiveActorCount) {
// We need to spin the event loop while we wait for all the actors to be
// cleaned up. We also set a timeout to force-kill any hanging actors.
TimerCallbackClosure closure(thread, liveActors.get());
MOZ_ALWAYS_SUCCEEDS(shutdownTimer->InitWithNamedFuncCallback(
&ShutdownTimerCallback, &closure, kShutdownTimerDelayMS,
nsITimer::TYPE_ONE_SHOT, "ParentImpl::ShutdownTimerCallback"));
SpinEventLoopUntil("ParentImpl::ShutdownBackgroundThread"_ns,
[&]() { return !sLiveActorCount; });
MOZ_ASSERT(liveActors->IsEmpty());
MOZ_ALWAYS_SUCCEEDS(shutdownTimer->Cancel());
}
// Shutdown will process all remaining events.
MOZ_ALWAYS_SUCCEEDS(thread->Shutdown());
}
}
// static
void ParentImpl::ShutdownTimerCallback(nsITimer* aTimer, void* aClosure) {
AssertIsInMainProcess();
AssertIsOnMainThread();
MOZ_ASSERT(sShutdownHasStarted);
MOZ_ASSERT(sLiveActorCount);
auto closure = static_cast<TimerCallbackClosure*>(aClosure);
MOZ_ASSERT(closure);
// Don't let the stack unwind until the ForceCloseBackgroundActorsRunnable has
// finished.
sLiveActorCount++;
InvokeAsync(
closure->mThread, __func__,
[liveActors = closure->mLiveActors]() {
MOZ_ASSERT(liveActors);
if (!liveActors->IsEmpty()) {
// Copy the array since calling Close() could mutate the
// actual array.
nsTArray<IToplevelProtocol*> actorsToClose(liveActors->Clone());
for (IToplevelProtocol* actor : actorsToClose) {
actor->Close();
}
}
return GenericPromise::CreateAndResolve(true, __func__);
})
->Then(GetCurrentSerialEventTarget(), __func__, []() {
MOZ_ASSERT(sLiveActorCount);
sLiveActorCount--;
});
}
void ParentImpl::Destroy() {
// May be called on any thread!
AssertIsInMainProcess();
MOZ_ALWAYS_SUCCEEDS(NS_DispatchToMainThread(
NewNonOwningRunnableMethod("ParentImpl::MainThreadActorDestroy", this,
&ParentImpl::MainThreadActorDestroy)));
}
void ParentImpl::MainThreadActorDestroy() {
AssertIsInMainProcess();
AssertIsOnMainThread();
MOZ_ASSERT_IF(!mIsOtherProcessActor, !mContent);
MOZ_ASSERT(sLiveActorCount);
sLiveActorCount--;
// This may be the last reference!
Release();
}
void ParentImpl::ActorDestroy(ActorDestroyReason aWhy) {
AssertIsInMainProcess();
AssertIsOnBackgroundThread();
MOZ_ASSERT(!mActorDestroyed);
MOZ_ASSERT_IF(mIsOtherProcessActor, mLiveActorArray);
BackgroundParentImpl::ActorDestroy(aWhy);
mActorDestroyed = true;
if (mLiveActorArray) {
MOZ_ALWAYS_TRUE(mLiveActorArray->RemoveElement(this));
mLiveActorArray = nullptr;
}
// This is tricky. We should be able to call Destroy() here directly because
// we're not going to touch 'this' or our MessageChannel any longer on this
// thread. Destroy() dispatches the MainThreadActorDestroy runnable and when
// it runs it will destroy 'this' and our associated MessageChannel. However,
// IPDL is about to call MessageChannel::Clear() on this thread! To avoid
// racing with the main thread we must ensure that the MessageChannel lives
// long enough to be cleared in this call stack.
MOZ_ALWAYS_SUCCEEDS(NS_DispatchToCurrentThread(NewNonOwningRunnableMethod(
"ParentImpl::Destroy", this, &ParentImpl::Destroy)));
}
NS_IMPL_ISUPPORTS(ParentImpl::ShutdownObserver, nsIObserver)
NS_IMETHODIMP
ParentImpl::ShutdownObserver::Observe(nsISupports* aSubject, const char* aTopic,
const char16_t* aData) {
AssertIsInMainProcess();
AssertIsOnMainThread();
MOZ_ASSERT(!sShutdownHasStarted);
MOZ_ASSERT(!strcmp(aTopic, NS_XPCOM_SHUTDOWN_THREADS_OBSERVER_ID));
sShutdownHasStarted = true;
// Do this first before calling (and spinning the event loop in)
// ShutdownBackgroundThread().
ChildImpl::Shutdown();
ShutdownBackgroundThread();
return NS_OK;
}
BackgroundStarterParent::BackgroundStarterParent(
ThreadsafeContentParentHandle* aContent, bool aCrossProcess)
: mCrossProcess(aCrossProcess), mContent(aContent) {
AssertIsOnMainThread();
AssertIsInMainProcess();
MOZ_ASSERT_IF(!mCrossProcess, !mContent);
MOZ_ASSERT_IF(!mCrossProcess, XRE_IsParentProcess());
}
void BackgroundStarterParent::SetLiveActorArray(
nsTArray<IToplevelProtocol*>* aLiveActorArray) {
AssertIsInMainProcess();
AssertIsOnBackgroundThread();
MOZ_ASSERT(aLiveActorArray);
MOZ_ASSERT(!aLiveActorArray->Contains(this));
MOZ_ASSERT(!mLiveActorArray);
MOZ_ASSERT_IF(!mCrossProcess, OtherPid() == base::GetCurrentProcId());
mLiveActorArray = aLiveActorArray;
mLiveActorArray->AppendElement(this);
}
IPCResult BackgroundStarterParent::RecvInitBackground(
Endpoint<PBackgroundParent>&& aEndpoint) {
AssertIsOnBackgroundThread();
if (!aEndpoint.IsValid()) {
return IPC_FAIL(this,
"Cannot initialize PBackground with invalid endpoint");
}
ParentImpl* actor = new ParentImpl(mContent, mCrossProcess);
// Take a reference on this thread. If Open() fails then we will release this
// reference in Destroy.
NS_ADDREF(actor);
ParentImpl::sLiveActorCount++;
if (!aEndpoint.Bind(actor)) {
actor->Destroy();
return IPC_OK();
}
if (mCrossProcess) {
actor->SetLiveActorArray(mLiveActorArray);
}
return IPC_OK();
}
void BackgroundStarterParent::ActorDestroy(ActorDestroyReason aReason) {
AssertIsOnBackgroundThread();
if (mLiveActorArray) {
MOZ_ALWAYS_TRUE(mLiveActorArray->RemoveElement(this));
mLiveActorArray = nullptr;
}
// Make sure to decrement `sLiveActorCount` on the main thread.
MOZ_ALWAYS_SUCCEEDS(NS_DispatchToMainThread(
NS_NewRunnableFunction("BackgroundStarterParent::MainThreadDestroy",
[] { ParentImpl::sLiveActorCount--; })));
}
// -----------------------------------------------------------------------------
// ChildImpl Implementation
// -----------------------------------------------------------------------------
// static
void ChildImpl::Startup() {
// This happens on the main thread but before XPCOM has started so we can't
// assert that we're being called on the main thread here.
sParentAndContentProcessThreadInfo.Startup();
sTLSIsOnBackgroundThread.infallibleInit();
nsCOMPtr<nsIObserverService> observerService = services::GetObserverService();
MOZ_RELEASE_ASSERT(observerService);
nsCOMPtr<nsIObserver> observer = new ShutdownObserver();
nsresult rv = observerService->AddObserver(
observer, NS_XPCOM_SHUTDOWN_THREADS_OBSERVER_ID, false);
MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
// Initialize a starter actor to allow starting PBackground within the parent
// process.
if (XRE_IsParentProcess()) {
Endpoint<PBackgroundStarterParent> parent;
Endpoint<PBackgroundStarterChild> child;
MOZ_ALWAYS_SUCCEEDS(PBackgroundStarter::CreateEndpoints(
EndpointProcInfo::Current(), EndpointProcInfo::Current(), &parent,
&child));
MOZ_ALWAYS_TRUE(ParentImpl::AllocStarter(nullptr, std::move(parent),
/* aCrossProcess */ false));
sParentAndContentProcessThreadInfo.InitStarter(std::move(child));
}
}
// static
void ChildImpl::Shutdown() {
AssertIsOnMainThread();
sParentAndContentProcessThreadInfo.Shutdown();
sShutdownHasStarted = true;
}
// static
PBackgroundChild* ChildImpl::GetForCurrentThread() {
MOZ_ASSERT(sParentAndContentProcessThreadInfo.mThreadLocalIndex !=
kBadThreadLocalIndex);
auto threadLocalInfo =
NS_IsMainThread()
? sParentAndContentProcessThreadInfo.mMainThreadInfo
: static_cast<ThreadLocalInfo*>(PR_GetThreadPrivate(
sParentAndContentProcessThreadInfo.mThreadLocalIndex));
if (!threadLocalInfo) {
return nullptr;
}
return threadLocalInfo->mActor;
}
/* static */
PBackgroundChild* ChildImpl::GetOrCreateForCurrentThread() {
return sParentAndContentProcessThreadInfo.GetOrCreateForCurrentThread();
}
// static
void ChildImpl::CloseForCurrentThread() {
MOZ_ASSERT(!NS_IsMainThread(),
"PBackground for the main thread should be shut down via "
"ChildImpl::Shutdown().");
sParentAndContentProcessThreadInfo.CloseForCurrentThread();
}
// static
BackgroundChildImpl::ThreadLocal* ChildImpl::GetThreadLocalForCurrentThread() {
MOZ_ASSERT(sParentAndContentProcessThreadInfo.mThreadLocalIndex !=
kBadThreadLocalIndex,
"BackgroundChild::Startup() was never called!");
auto threadLocalInfo =
NS_IsMainThread()
? sParentAndContentProcessThreadInfo.mMainThreadInfo
: static_cast<ThreadLocalInfo*>(PR_GetThreadPrivate(
sParentAndContentProcessThreadInfo.mThreadLocalIndex));
if (!threadLocalInfo) {
return nullptr;
}
if (!threadLocalInfo->mConsumerThreadLocal) {
threadLocalInfo->mConsumerThreadLocal =
MakeUnique<BackgroundChildImpl::ThreadLocal>();
}
return threadLocalInfo->mConsumerThreadLocal.get();
}
// static
void ChildImpl::InitContentStarter(mozilla::dom::ContentChild* aContent) {
sParentAndContentProcessThreadInfo.InitStarter(aContent);
}
// static
void ChildImpl::ThreadLocalDestructor(void* aThreadLocal) {
auto threadLocalInfo = static_cast<ThreadLocalInfo*>(aThreadLocal);
if (threadLocalInfo) {
MOZ_ASSERT(threadLocalInfo->mClosed);
if (threadLocalInfo->mActor) {
threadLocalInfo->mActor->Close();
threadLocalInfo->mActor->AssertActorDestroyed();
}
delete threadLocalInfo;
}
}
void ChildImpl::ActorDestroy(ActorDestroyReason aWhy) {
AssertIsOnOwningThread();
#ifdef DEBUG
MOZ_ASSERT(!mActorDestroyed);
mActorDestroyed = true;
#endif
BackgroundChildImpl::ActorDestroy(aWhy);
}
NS_IMPL_ISUPPORTS(ChildImpl::ShutdownObserver, nsIObserver)
NS_IMETHODIMP
ChildImpl::ShutdownObserver::Observe(nsISupports* aSubject, const char* aTopic,
const char16_t* aData) {
AssertIsOnMainThread();
MOZ_ASSERT(!strcmp(aTopic, NS_XPCOM_SHUTDOWN_THREADS_OBSERVER_ID));
ChildImpl::Shutdown();
return NS_OK;
}