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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ipc/ipc_sync_message_filter.h"
#include "base/check.h"
#include "base/functional/bind.h"
#include "base/location.h"
#include "base/memory/ptr_util.h"
#include "base/memory/ref_counted.h"
#include "base/synchronization/waitable_event.h"
#include "base/task/single_thread_task_runner.h"
#include "base/trace_event/trace_event.h"
#include "ipc/ipc_channel.h"
#include "ipc/ipc_sync_message.h"
#include "mojo/public/cpp/bindings/associated_receiver.h"
#include "mojo/public/cpp/bindings/sync_handle_registry.h"
namespace IPC {
namespace {
// A generic callback used when watching handles synchronously. Sets |*signal|
// to true.
void OnEventReady(bool* signal) {
*signal = true;
}
} // namespace
bool SyncMessageFilter::Send(Message* message) {
if (!message->is_sync()) {
{
base::AutoLock auto_lock(lock_);
if (!io_task_runner_.get()) {
pending_messages_.emplace_back(base::WrapUnique(message));
return true;
}
}
io_task_runner_->PostTask(
FROM_HERE,
base::BindOnce(&SyncMessageFilter::SendOnIOThread, this, message));
return true;
}
auto owned_event = std::make_unique<base::WaitableEvent>(
base::WaitableEvent::ResetPolicy::MANUAL,
base::WaitableEvent::InitialState::NOT_SIGNALED);
base::WaitableEvent* done_event = owned_event.get();
PendingSyncMsg pending_message(
SyncMessage::GetMessageId(*message),
static_cast<SyncMessage*>(message)->TakeReplyDeserializer(),
std::move(owned_event));
{
base::AutoLock auto_lock(lock_);
// Can't use this class on the main thread or else it can lead to deadlocks.
// Also by definition, can't use this on IO thread since we're blocking it.
if (base::SingleThreadTaskRunner::HasCurrentDefault()) {
DCHECK(base::SingleThreadTaskRunner::GetCurrentDefault() !=
listener_task_runner_);
DCHECK(base::SingleThreadTaskRunner::GetCurrentDefault() !=
io_task_runner_);
}
pending_sync_messages_.insert(&pending_message);
if (io_task_runner_.get()) {
io_task_runner_->PostTask(
FROM_HERE,
base::BindOnce(&SyncMessageFilter::SendOnIOThread, this, message));
} else {
pending_messages_.emplace_back(base::WrapUnique(message));
}
}
{
bool done = false;
bool shutdown = false;
scoped_refptr<mojo::SyncHandleRegistry> registry =
mojo::SyncHandleRegistry::current();
mojo::SyncHandleRegistry::EventCallbackSubscription shutdown_subscription =
registry->RegisterEvent(shutdown_event_,
base::BindRepeating(&OnEventReady, &shutdown));
mojo::SyncHandleRegistry::EventCallbackSubscription done_subscription =
registry->RegisterEvent(done_event,
base::BindRepeating(&OnEventReady, &done));
const bool* stop_flags[] = {&done, &shutdown};
registry->Wait(stop_flags, 2);
if (done) {
TRACE_EVENT_WITH_FLOW0("toplevel.flow", "SyncMessageFilter::Send",
done_event, TRACE_EVENT_FLAG_FLOW_IN);
}
}
{
base::AutoLock auto_lock(lock_);
pending_sync_messages_.erase(&pending_message);
}
return pending_message.send_result;
}
void SyncMessageFilter::OnFilterAdded(Channel* channel) {
std::vector<std::unique_ptr<Message>> pending_messages;
{
base::AutoLock auto_lock(lock_);
channel_ = channel;
io_task_runner_ = base::SingleThreadTaskRunner::GetCurrentDefault();
std::swap(pending_messages_, pending_messages);
}
for (auto& msg : pending_messages)
SendOnIOThread(msg.release());
}
void SyncMessageFilter::OnChannelError() {
base::AutoLock auto_lock(lock_);
channel_ = nullptr;
SignalAllEvents();
}
void SyncMessageFilter::OnChannelClosing() {
base::AutoLock auto_lock(lock_);
channel_ = nullptr;
SignalAllEvents();
}
bool SyncMessageFilter::OnMessageReceived(const Message& message) {
base::AutoLock auto_lock(lock_);
for (PendingSyncMessages::iterator iter = pending_sync_messages_.begin();
iter != pending_sync_messages_.end(); ++iter) {
if (SyncMessage::IsMessageReplyTo(message, (*iter)->id)) {
if (!message.is_reply_error()) {
(*iter)->send_result =
(*iter)->deserializer->SerializeOutputParameters(message);
}
TRACE_EVENT_WITH_FLOW0(
"toplevel.flow", "SyncMessageFilter::OnMessageReceived",
(*iter)->done_event.get(), TRACE_EVENT_FLAG_FLOW_OUT);
(*iter)->done_event->Signal();
return true;
}
}
return false;
}
SyncMessageFilter::SyncMessageFilter(base::WaitableEvent* shutdown_event)
: channel_(nullptr),
listener_task_runner_(base::SingleThreadTaskRunner::GetCurrentDefault()),
shutdown_event_(shutdown_event) {}
SyncMessageFilter::~SyncMessageFilter() = default;
void SyncMessageFilter::SendOnIOThread(Message* message) {
if (channel_) {
channel_->Send(message);
return;
}
if (message->is_sync()) {
// We don't know which thread sent it, but it doesn't matter, just signal
// them all.
base::AutoLock auto_lock(lock_);
SignalAllEvents();
}
delete message;
}
void SyncMessageFilter::SignalAllEvents() {
lock_.AssertAcquired();
for (PendingSyncMessages::iterator iter = pending_sync_messages_.begin();
iter != pending_sync_messages_.end(); ++iter) {
TRACE_EVENT_WITH_FLOW0(
"toplevel.flow", "SyncMessageFilter::SignalAllEvents",
(*iter)->done_event.get(), TRACE_EVENT_FLAG_FLOW_OUT);
(*iter)->done_event->Signal();
}
}
void SyncMessageFilter::GetRemoteAssociatedInterface(
mojo::GenericPendingAssociatedReceiver receiver) {
base::AutoLock auto_lock(lock_);
DCHECK(io_task_runner_ && io_task_runner_->BelongsToCurrentThread());
if (!channel_) {
// Attach the associated interface to a disconnected pipe, so that the
// associated interface pointer can be used to make calls (which are
// dropped).
mojo::AssociateWithDisconnectedPipe(receiver.PassHandle());
return;
}
Channel::AssociatedInterfaceSupport* support =
channel_->GetAssociatedInterfaceSupport();
support->GetRemoteAssociatedInterface(std::move(receiver));
}
} // namespace IPC
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