mirror of
https://github.com/classilla/tenfourfox.git
synced 2024-09-10 11:54:40 +00:00
2273 lines
73 KiB
C++
2273 lines
73 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* vim: sw=4 ts=4 et :
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*/
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "mozilla/ipc/MessageChannel.h"
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#include "mozilla/ipc/ProtocolUtils.h"
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#include "mozilla/dom/ScriptSettings.h"
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#include "mozilla/Assertions.h"
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#include "mozilla/DebugOnly.h"
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#include "mozilla/Move.h"
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#include "mozilla/SizePrintfMacros.h"
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#include "mozilla/Telemetry.h"
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#include "nsDebug.h"
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#include "nsISupportsImpl.h"
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#include "nsContentUtils.h"
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#include "prprf.h"
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// Undo the damage done by mozzconf.h
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#undef compress
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// Logging seems to be somewhat broken on b2g.
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#ifdef MOZ_B2G
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#define IPC_LOG(...)
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#else
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static LazyLogModule sLogModule("ipc");
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#define IPC_LOG(...) MOZ_LOG(sLogModule, LogLevel::Debug, (__VA_ARGS__))
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#endif
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/*
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* IPC design:
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*
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* There are three kinds of messages: async, sync, and intr. Sync and intr
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* messages are blocking. Only intr and high-priority sync messages can nest.
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*
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* Terminology: To dispatch a message Foo is to run the RecvFoo code for
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* it. This is also called "handling" the message.
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*
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* Sync and async messages have priorities while intr messages always have
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* normal priority. The three possible priorities are normal, high, and urgent.
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* The intended uses of these priorities are:
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* NORMAL - most messages.
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* HIGH - CPOW-related messages, which can go in either direction.
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* URGENT - messages where we don't want to dispatch
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* incoming CPOWs while waiting for the response.
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* Async messages cannot have HIGH priority.
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*
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* To avoid jank, the parent process is not allowed to send sync messages of
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* normal priority. When a process is waiting for a response to a sync message
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* M0, it will dispatch an incoming message M if:
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* 1. M has a higher priority than M0, or
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* 2. if M has the same priority as M0 and we're in the child, or
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* 3. if M has the same priority as M0 and it was sent by the other side
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* while dispatching M0 (nesting).
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* The idea is that higher priority messages should take precendence, and we
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* also want to allow nesting. The purpose of rule 2 is to handle a race where
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* both processes send to each other simultaneously. In this case, we resolve
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* the race in favor of the parent (so the child dispatches first).
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*
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* Messages satisfy the following properties:
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* A. When waiting for a response to a sync message, we won't dispatch any
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* messages of lower priority.
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* B. Messages of the same priority will be dispatched roughly in the
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* order they were sent. The exception is when the parent and child send
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* sync messages to each other simulataneously. In this case, the parent's
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* message is dispatched first. While it is dispatched, the child may send
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* further nested messages, and these messages may be dispatched before the
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* child's original message. We can consider ordering to be preserved here
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* because we pretend that the child's original message wasn't sent until
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* after the parent's message is finished being dispatched.
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*
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* When waiting for a sync message reply, we dispatch an async message only if
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* it has URGENT priority. Normally URGENT async messages are sent only from the
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* child. However, the parent can send URGENT async messages when it is creating
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* a bridged protocol.
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*
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* Intr messages are blocking but not prioritized. While waiting for an intr
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* response, all incoming messages are dispatched until a response is
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* received. Intr messages also can be nested. When two intr messages race with
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* each other, a similar scheme is used to ensure that one side wins. The
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* winning side is chosen based on the message type.
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*
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* Intr messages differ from sync messages in that, while sending an intr
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* message, we may dispatch an async message. This causes some additional
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* complexity. One issue is that replies can be received out of order. It's also
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* more difficult to determine whether one message is nested inside
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* another. Consequently, intr handling uses mOutOfTurnReplies and
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* mRemoteStackDepthGuess, which are not needed for sync messages.
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*/
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using namespace mozilla;
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using namespace std;
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using mozilla::dom::AutoNoJSAPI;
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using mozilla::dom::ScriptSettingsInitialized;
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using mozilla::MonitorAutoLock;
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using mozilla::MonitorAutoUnlock;
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template<>
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struct RunnableMethodTraits<mozilla::ipc::MessageChannel>
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{
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static void RetainCallee(mozilla::ipc::MessageChannel* obj) { }
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static void ReleaseCallee(mozilla::ipc::MessageChannel* obj) { }
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};
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#define IPC_ASSERT(_cond, ...) \
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do { \
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if (!(_cond)) \
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DebugAbort(__FILE__, __LINE__, #_cond,## __VA_ARGS__); \
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} while (0)
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static MessageChannel* gParentProcessBlocker;
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namespace mozilla {
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namespace ipc {
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const int32_t MessageChannel::kNoTimeout = INT32_MIN;
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// static
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bool MessageChannel::sIsPumpingMessages = false;
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enum Direction
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{
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IN_MESSAGE,
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OUT_MESSAGE
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};
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class MessageChannel::InterruptFrame
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{
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private:
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enum Semantics
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{
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INTR_SEMS,
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SYNC_SEMS,
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ASYNC_SEMS
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};
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public:
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InterruptFrame(Direction direction, const Message* msg)
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: mMessageName(strdup(msg->name())),
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mMessageRoutingId(msg->routing_id()),
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mMesageSemantics(msg->is_interrupt() ? INTR_SEMS :
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msg->is_sync() ? SYNC_SEMS :
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ASYNC_SEMS),
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mDirection(direction),
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mMoved(false)
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{
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MOZ_ASSERT(mMessageName);
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}
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InterruptFrame(InterruptFrame&& aOther)
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{
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MOZ_ASSERT(aOther.mMessageName);
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mMessageName = aOther.mMessageName;
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aOther.mMessageName = nullptr;
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aOther.mMoved = true;
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mMessageRoutingId = aOther.mMessageRoutingId;
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mMesageSemantics = aOther.mMesageSemantics;
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mDirection = aOther.mDirection;
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}
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~InterruptFrame()
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{
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MOZ_ASSERT_IF(!mMessageName, mMoved);
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if (mMessageName)
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free(const_cast<char*>(mMessageName));
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}
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InterruptFrame& operator=(InterruptFrame&& aOther)
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{
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MOZ_RELEASE_ASSERT(&aOther != this);
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this->~InterruptFrame();
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new (this) InterruptFrame(mozilla::Move(aOther));
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return *this;
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}
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bool IsInterruptIncall() const
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{
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return INTR_SEMS == mMesageSemantics && IN_MESSAGE == mDirection;
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}
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bool IsInterruptOutcall() const
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{
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return INTR_SEMS == mMesageSemantics && OUT_MESSAGE == mDirection;
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}
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bool IsOutgoingSync() const {
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return (mMesageSemantics == INTR_SEMS || mMesageSemantics == SYNC_SEMS) &&
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mDirection == OUT_MESSAGE;
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}
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void Describe(int32_t* id, const char** dir, const char** sems,
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const char** name) const
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{
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*id = mMessageRoutingId;
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*dir = (IN_MESSAGE == mDirection) ? "in" : "out";
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*sems = (INTR_SEMS == mMesageSemantics) ? "intr" :
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(SYNC_SEMS == mMesageSemantics) ? "sync" :
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"async";
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*name = mMessageName;
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}
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int32_t GetRoutingId() const
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{
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return mMessageRoutingId;
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}
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private:
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const char* mMessageName;
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int32_t mMessageRoutingId;
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Semantics mMesageSemantics;
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Direction mDirection;
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DebugOnly<bool> mMoved;
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// Disable harmful methods.
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InterruptFrame(const InterruptFrame& aOther) = delete;
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InterruptFrame& operator=(const InterruptFrame&) = delete;
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};
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class MOZ_STACK_CLASS MessageChannel::CxxStackFrame
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{
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public:
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CxxStackFrame(MessageChannel& that, Direction direction, const Message* msg)
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: mThat(that)
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{
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mThat.AssertWorkerThread();
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if (mThat.mCxxStackFrames.empty())
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mThat.EnteredCxxStack();
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mThat.mCxxStackFrames.append(InterruptFrame(direction, msg));
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const InterruptFrame& frame = mThat.mCxxStackFrames.back();
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if (frame.IsInterruptIncall())
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mThat.EnteredCall();
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if (frame.IsOutgoingSync())
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mThat.EnteredSyncSend();
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mThat.mSawInterruptOutMsg |= frame.IsInterruptOutcall();
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}
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~CxxStackFrame() {
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mThat.AssertWorkerThread();
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MOZ_ASSERT(!mThat.mCxxStackFrames.empty());
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const InterruptFrame& frame = mThat.mCxxStackFrames.back();
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bool exitingSync = frame.IsOutgoingSync();
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bool exitingCall = frame.IsInterruptIncall();
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mThat.mCxxStackFrames.shrinkBy(1);
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bool exitingStack = mThat.mCxxStackFrames.empty();
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// mListener could have gone away if Close() was called while
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// MessageChannel code was still on the stack
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if (!mThat.mListener)
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return;
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if (exitingCall)
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mThat.ExitedCall();
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if (exitingSync)
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mThat.ExitedSyncSend();
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if (exitingStack)
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mThat.ExitedCxxStack();
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}
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private:
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MessageChannel& mThat;
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// Disable harmful methods.
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CxxStackFrame() = delete;
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CxxStackFrame(const CxxStackFrame&) = delete;
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CxxStackFrame& operator=(const CxxStackFrame&) = delete;
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};
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namespace {
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class MOZ_RAII MaybeScriptBlocker {
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public:
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explicit MaybeScriptBlocker(MessageChannel *aChannel, bool aBlock
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MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
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: mBlocked(aChannel->ShouldBlockScripts() && aBlock)
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{
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MOZ_GUARD_OBJECT_NOTIFIER_INIT;
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if (mBlocked) {
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nsContentUtils::AddScriptBlocker();
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}
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}
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~MaybeScriptBlocker() {
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if (mBlocked) {
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nsContentUtils::RemoveScriptBlocker();
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}
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}
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private:
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MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
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bool mBlocked;
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};
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} // namespace
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MessageChannel::MessageChannel(MessageListener *aListener)
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: mListener(aListener),
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mChannelState(ChannelClosed),
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mSide(UnknownSide),
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mLink(nullptr),
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mWorkerLoop(nullptr),
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mChannelErrorTask(nullptr),
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mWorkerLoopID(-1),
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mTimeoutMs(kNoTimeout),
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mInTimeoutSecondHalf(false),
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mNextSeqno(0),
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mLastSendError(SyncSendError::SendSuccess),
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mAwaitingSyncReply(false),
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mAwaitingSyncReplyPriority(0),
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mDispatchingSyncMessage(false),
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mDispatchingSyncMessagePriority(0),
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mDispatchingAsyncMessage(false),
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mDispatchingAsyncMessagePriority(0),
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mCurrentTransaction(0),
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mPendingSendPriorities(0),
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mTimedOutMessageSeqno(0),
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mTimedOutMessagePriority(0),
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mRecvdErrors(0),
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mRemoteStackDepthGuess(false),
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mSawInterruptOutMsg(false),
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mIsWaitingForIncoming(false),
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mAbortOnError(false),
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mBlockScripts(false),
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mFlags(REQUIRE_DEFAULT),
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mPeerPidSet(false),
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mPeerPid(-1)
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{
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MOZ_COUNT_CTOR(ipc::MessageChannel);
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#ifdef OS_WIN
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mTopFrame = nullptr;
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mIsSyncWaitingOnNonMainThread = false;
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#endif
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mDequeueOneTask = new RefCountedTask(NewRunnableMethod(
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this,
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&MessageChannel::OnMaybeDequeueOne));
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mOnChannelConnectedTask = new RefCountedTask(NewRunnableMethod(
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this,
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&MessageChannel::DispatchOnChannelConnected));
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#ifdef OS_WIN
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mEvent = CreateEventW(nullptr, TRUE, FALSE, nullptr);
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NS_ASSERTION(mEvent, "CreateEvent failed! Nothing is going to work!");
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#endif
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}
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MessageChannel::~MessageChannel()
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{
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MOZ_COUNT_DTOR(ipc::MessageChannel);
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IPC_ASSERT(mCxxStackFrames.empty(), "mismatched CxxStackFrame ctor/dtors");
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#ifdef OS_WIN
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DebugOnly<BOOL> ok = CloseHandle(mEvent);
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MOZ_ASSERT(ok);
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#endif
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Clear();
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}
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static void
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PrintErrorMessage(Side side, const char* channelName, const char* msg)
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{
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const char *from = (side == ChildSide)
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? "Child"
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: ((side == ParentSide) ? "Parent" : "Unknown");
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printf_stderr("\n###!!! [%s][%s] Error: %s\n\n", from, channelName, msg);
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}
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bool
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MessageChannel::Connected() const
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{
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mMonitor->AssertCurrentThreadOwns();
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// The transport layer allows us to send messages before
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// receiving the "connected" ack from the remote side.
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return (ChannelOpening == mChannelState || ChannelConnected == mChannelState);
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}
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bool
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MessageChannel::CanSend() const
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{
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if (!mMonitor) {
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return false;
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}
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MonitorAutoLock lock(*mMonitor);
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return Connected();
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}
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void
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MessageChannel::Clear()
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{
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// Don't clear mWorkerLoopID; we use it in AssertLinkThread() and
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// AssertWorkerThread().
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//
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// Also don't clear mListener. If we clear it, then sending a message
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// through this channel after it's Clear()'ed can cause this process to
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// crash.
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//
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// In practice, mListener owns the channel, so the channel gets deleted
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// before mListener. But just to be safe, mListener is a weak pointer.
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if (gParentProcessBlocker == this) {
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gParentProcessBlocker = nullptr;
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}
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mDequeueOneTask->Cancel();
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mWorkerLoop = nullptr;
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delete mLink;
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mLink = nullptr;
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mOnChannelConnectedTask->Cancel();
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if (mChannelErrorTask) {
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mChannelErrorTask->Cancel();
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mChannelErrorTask = nullptr;
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}
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// Free up any memory used by pending messages.
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mPending.clear();
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mRecvd = nullptr;
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mOutOfTurnReplies.clear();
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while (!mDeferred.empty()) {
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mDeferred.pop();
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}
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}
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bool
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MessageChannel::Open(Transport* aTransport, MessageLoop* aIOLoop, Side aSide)
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{
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NS_PRECONDITION(!mLink, "Open() called > once");
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mMonitor = new RefCountedMonitor();
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mWorkerLoop = MessageLoop::current();
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mWorkerLoopID = mWorkerLoop->id();
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ProcessLink *link = new ProcessLink(this);
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link->Open(aTransport, aIOLoop, aSide); // :TODO: n.b.: sets mChild
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mLink = link;
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return true;
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}
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bool
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MessageChannel::Open(MessageChannel *aTargetChan, MessageLoop *aTargetLoop, Side aSide)
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{
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// Opens a connection to another thread in the same process.
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// This handshake proceeds as follows:
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// - Let A be the thread initiating the process (either child or parent)
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// and B be the other thread.
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// - A spawns thread for B, obtaining B's message loop
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// - A creates ProtocolChild and ProtocolParent instances.
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// Let PA be the one appropriate to A and PB the side for B.
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// - A invokes PA->Open(PB, ...):
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// - set state to mChannelOpening
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// - this will place a work item in B's worker loop (see next bullet)
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// and then spins until PB->mChannelState becomes mChannelConnected
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// - meanwhile, on PB's worker loop, the work item is removed and:
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// - invokes PB->SlaveOpen(PA, ...):
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// - sets its state and that of PA to Connected
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NS_PRECONDITION(aTargetChan, "Need a target channel");
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NS_PRECONDITION(ChannelClosed == mChannelState, "Not currently closed");
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CommonThreadOpenInit(aTargetChan, aSide);
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Side oppSide = UnknownSide;
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switch(aSide) {
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case ChildSide: oppSide = ParentSide; break;
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case ParentSide: oppSide = ChildSide; break;
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case UnknownSide: break;
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}
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mMonitor = new RefCountedMonitor();
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MonitorAutoLock lock(*mMonitor);
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mChannelState = ChannelOpening;
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aTargetLoop->PostTask(
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FROM_HERE,
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NewRunnableMethod(aTargetChan, &MessageChannel::OnOpenAsSlave, this, oppSide));
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while (ChannelOpening == mChannelState)
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mMonitor->Wait();
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NS_ASSERTION(ChannelConnected == mChannelState, "not connected when awoken");
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return (ChannelConnected == mChannelState);
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}
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|
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void
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MessageChannel::OnOpenAsSlave(MessageChannel *aTargetChan, Side aSide)
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{
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// Invoked when the other side has begun the open.
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NS_PRECONDITION(ChannelClosed == mChannelState,
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"Not currently closed");
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NS_PRECONDITION(ChannelOpening == aTargetChan->mChannelState,
|
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"Target channel not in the process of opening");
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CommonThreadOpenInit(aTargetChan, aSide);
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mMonitor = aTargetChan->mMonitor;
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MonitorAutoLock lock(*mMonitor);
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NS_ASSERTION(ChannelOpening == aTargetChan->mChannelState,
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"Target channel not in the process of opening");
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mChannelState = ChannelConnected;
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aTargetChan->mChannelState = ChannelConnected;
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aTargetChan->mMonitor->Notify();
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}
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|
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void
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MessageChannel::CommonThreadOpenInit(MessageChannel *aTargetChan, Side aSide)
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|
{
|
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mWorkerLoop = MessageLoop::current();
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|
mWorkerLoopID = mWorkerLoop->id();
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mLink = new ThreadLink(this, aTargetChan);
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mSide = aSide;
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}
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bool
|
|
MessageChannel::Echo(Message* aMsg)
|
|
{
|
|
nsAutoPtr<Message> msg(aMsg);
|
|
AssertWorkerThread();
|
|
mMonitor->AssertNotCurrentThreadOwns();
|
|
if (MSG_ROUTING_NONE == msg->routing_id()) {
|
|
ReportMessageRouteError("MessageChannel::Echo");
|
|
return false;
|
|
}
|
|
|
|
MonitorAutoLock lock(*mMonitor);
|
|
|
|
if (!Connected()) {
|
|
ReportConnectionError("MessageChannel", msg);
|
|
return false;
|
|
}
|
|
|
|
mLink->EchoMessage(msg.forget());
|
|
return true;
|
|
}
|
|
|
|
bool
|
|
MessageChannel::Send(Message* aMsg)
|
|
{
|
|
CxxStackFrame frame(*this, OUT_MESSAGE, aMsg);
|
|
|
|
nsAutoPtr<Message> msg(aMsg);
|
|
AssertWorkerThread();
|
|
mMonitor->AssertNotCurrentThreadOwns();
|
|
if (MSG_ROUTING_NONE == msg->routing_id()) {
|
|
ReportMessageRouteError("MessageChannel::Send");
|
|
return false;
|
|
}
|
|
|
|
MonitorAutoLock lock(*mMonitor);
|
|
if (!Connected()) {
|
|
ReportConnectionError("MessageChannel", msg);
|
|
return false;
|
|
}
|
|
mLink->SendMessage(msg.forget());
|
|
return true;
|
|
}
|
|
|
|
class CancelMessage : public IPC::Message
|
|
{
|
|
public:
|
|
explicit CancelMessage(int transaction) :
|
|
IPC::Message(MSG_ROUTING_NONE, CANCEL_MESSAGE_TYPE, PRIORITY_NORMAL)
|
|
{
|
|
set_transaction_id(transaction);
|
|
}
|
|
static bool Read(const Message* msg) {
|
|
return true;
|
|
}
|
|
void Log(const std::string& aPrefix, FILE* aOutf) const {
|
|
fputs("(special `Cancel' message)", aOutf);
|
|
}
|
|
};
|
|
|
|
bool
|
|
MessageChannel::MaybeInterceptSpecialIOMessage(const Message& aMsg)
|
|
{
|
|
AssertLinkThread();
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
|
|
if (MSG_ROUTING_NONE == aMsg.routing_id()) {
|
|
if (GOODBYE_MESSAGE_TYPE == aMsg.type()) {
|
|
// :TODO: Sort out Close() on this side racing with Close() on the
|
|
// other side
|
|
mChannelState = ChannelClosing;
|
|
if (LoggingEnabled()) {
|
|
printf("NOTE: %s process received `Goodbye', closing down\n",
|
|
(mSide == ChildSide) ? "child" : "parent");
|
|
}
|
|
return true;
|
|
} else if (CANCEL_MESSAGE_TYPE == aMsg.type()) {
|
|
IPC_LOG("Cancel from message");
|
|
CancelTransaction(aMsg.transaction_id());
|
|
NotifyWorkerThread();
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool
|
|
MessageChannel::ShouldDeferMessage(const Message& aMsg)
|
|
{
|
|
// Never defer messages that have the highest priority, even async
|
|
// ones. This is safe because only the child can send these messages, so
|
|
// they can never nest.
|
|
if (aMsg.priority() == IPC::Message::PRIORITY_URGENT)
|
|
return false;
|
|
|
|
// Unless they're urgent, we always defer async messages.
|
|
if (!aMsg.is_sync()) {
|
|
MOZ_ASSERT(aMsg.priority() == IPC::Message::PRIORITY_NORMAL);
|
|
return true;
|
|
}
|
|
|
|
int msgPrio = aMsg.priority();
|
|
int waitingPrio = AwaitingSyncReplyPriority();
|
|
|
|
// Always defer if the priority of the incoming message is less than the
|
|
// priority of the message we're awaiting.
|
|
if (msgPrio < waitingPrio)
|
|
return true;
|
|
|
|
// Never defer if the message has strictly greater priority.
|
|
if (msgPrio > waitingPrio)
|
|
return false;
|
|
|
|
// When both sides send sync messages of the same priority, we resolve the
|
|
// race by dispatching in the child and deferring the incoming message in
|
|
// the parent. However, the parent still needs to dispatch nested sync
|
|
// messages.
|
|
//
|
|
// Deferring in the parent only sort of breaks message ordering. When the
|
|
// child's message comes in, we can pretend the child hasn't quite
|
|
// finished sending it yet. Since the message is sync, we know that the
|
|
// child hasn't moved on yet.
|
|
return mSide == ParentSide && aMsg.transaction_id() != mCurrentTransaction;
|
|
}
|
|
|
|
// Predicate that is true for messages that should be consolidated if 'compress' is set.
|
|
class MatchingKinds {
|
|
typedef IPC::Message Message;
|
|
Message::msgid_t mType;
|
|
int32_t mRoutingId;
|
|
public:
|
|
MatchingKinds(Message::msgid_t aType, int32_t aRoutingId) :
|
|
mType(aType), mRoutingId(aRoutingId) {}
|
|
bool operator()(const Message &msg) {
|
|
return msg.type() == mType && msg.routing_id() == mRoutingId;
|
|
}
|
|
};
|
|
|
|
void
|
|
MessageChannel::OnMessageReceivedFromLink(const Message& aMsg)
|
|
{
|
|
AssertLinkThread();
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
|
|
if (MaybeInterceptSpecialIOMessage(aMsg))
|
|
return;
|
|
|
|
// Regardless of the Interrupt stack, if we're awaiting a sync reply,
|
|
// we know that it needs to be immediately handled to unblock us.
|
|
if (aMsg.is_sync() && aMsg.is_reply()) {
|
|
IPC_LOG("Received reply seqno=%d xid=%d", aMsg.seqno(), aMsg.transaction_id());
|
|
|
|
if (aMsg.seqno() == mTimedOutMessageSeqno) {
|
|
// Drop the message, but allow future sync messages to be sent.
|
|
IPC_LOG("Received reply to timedout message; igoring; xid=%d", mTimedOutMessageSeqno);
|
|
EndTimeout();
|
|
return;
|
|
}
|
|
|
|
MOZ_ASSERT(aMsg.transaction_id() == mCurrentTransaction);
|
|
MOZ_ASSERT(AwaitingSyncReply());
|
|
MOZ_ASSERT(!mRecvd);
|
|
MOZ_ASSERT(!mTimedOutMessageSeqno);
|
|
|
|
// Rather than storing errors in mRecvd, we mark them in
|
|
// mRecvdErrors. We need a counter because multiple replies can arrive
|
|
// when a timeout happens, as in the following example. Imagine the
|
|
// child is running slowly. The parent sends a sync message P1. It times
|
|
// out. The child eventually sends a sync message C1. While waiting for
|
|
// the C1 response, the child dispatches P1. In doing so, it sends sync
|
|
// message C2. At that point, it's valid for the parent to send error
|
|
// responses for both C1 and C2.
|
|
if (aMsg.is_reply_error()) {
|
|
mRecvdErrors++;
|
|
NotifyWorkerThread();
|
|
return;
|
|
}
|
|
|
|
mRecvd = new Message(aMsg);
|
|
NotifyWorkerThread();
|
|
return;
|
|
}
|
|
|
|
// Prioritized messages cannot be compressed.
|
|
MOZ_ASSERT_IF(aMsg.compress_type() != IPC::Message::COMPRESSION_NONE,
|
|
aMsg.priority() == IPC::Message::PRIORITY_NORMAL);
|
|
|
|
bool compress = false;
|
|
if (aMsg.compress_type() == IPC::Message::COMPRESSION_ENABLED) {
|
|
compress = (!mPending.empty() &&
|
|
mPending.back().type() == aMsg.type() &&
|
|
mPending.back().routing_id() == aMsg.routing_id());
|
|
if (compress) {
|
|
// This message type has compression enabled, and the back of the
|
|
// queue was the same message type and routed to the same destination.
|
|
// Replace it with the newer message.
|
|
MOZ_ASSERT(mPending.back().compress_type() ==
|
|
IPC::Message::COMPRESSION_ENABLED);
|
|
mPending.pop_back();
|
|
}
|
|
} else if (aMsg.compress_type() == IPC::Message::COMPRESSION_ALL) {
|
|
// Check the message queue for another message with this type/destination.
|
|
auto it = std::find_if(mPending.rbegin(), mPending.rend(),
|
|
MatchingKinds(aMsg.type(), aMsg.routing_id()));
|
|
if (it != mPending.rend()) {
|
|
// This message type has compression enabled, and the queue holds
|
|
// a message with the same message type and routed to the same destination.
|
|
// Erase it. Note that, since we always compress these redundancies, There Can
|
|
// Be Only One.
|
|
compress = true;
|
|
MOZ_ASSERT((*it).compress_type() == IPC::Message::COMPRESSION_ALL);
|
|
mPending.erase((++it).base());
|
|
}
|
|
}
|
|
|
|
bool wakeUpSyncSend = AwaitingSyncReply() && !ShouldDeferMessage(aMsg);
|
|
|
|
bool shouldWakeUp = AwaitingInterruptReply() ||
|
|
wakeUpSyncSend ||
|
|
AwaitingIncomingMessage();
|
|
|
|
// Although we usually don't need to post an OnMaybeDequeueOne task if
|
|
// shouldWakeUp is true, it's easier to post anyway than to have to
|
|
// guarantee that every Send call processes everything it's supposed to
|
|
// before returning.
|
|
bool shouldPostTask = !shouldWakeUp || wakeUpSyncSend;
|
|
|
|
IPC_LOG("Receive on link thread; seqno=%d, xid=%d, shouldWakeUp=%d",
|
|
aMsg.seqno(), aMsg.transaction_id(), shouldWakeUp);
|
|
|
|
// There are three cases we're concerned about, relating to the state of the
|
|
// main thread:
|
|
//
|
|
// (1) We are waiting on a sync reply - main thread is blocked on the
|
|
// IPC monitor.
|
|
// - If the message is high priority, we wake up the main thread to
|
|
// deliver the message depending on ShouldDeferMessage. Otherwise, we
|
|
// leave it in the mPending queue, posting a task to the main event
|
|
// loop, where it will be processed once the synchronous reply has been
|
|
// received.
|
|
//
|
|
// (2) We are waiting on an Interrupt reply - main thread is blocked on the
|
|
// IPC monitor.
|
|
// - Always notify and wake up the main thread.
|
|
//
|
|
// (3) We are not waiting on a reply.
|
|
// - We post a task to the main event loop.
|
|
//
|
|
// Note that, we may notify the main thread even though the monitor is not
|
|
// blocked. This is okay, since we always check for pending events before
|
|
// blocking again.
|
|
|
|
mPending.push_back(aMsg);
|
|
|
|
if (shouldWakeUp) {
|
|
NotifyWorkerThread();
|
|
}
|
|
|
|
if (shouldPostTask) {
|
|
if (!compress) {
|
|
// If we compressed away the previous message, we'll re-use
|
|
// its pending task.
|
|
mWorkerLoop->PostTask(FROM_HERE, new DequeueTask(mDequeueOneTask));
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
MessageChannel::ProcessPendingRequests(int seqno, int transaction)
|
|
{
|
|
IPC_LOG("ProcessPendingRequests for seqno=%d, xid=%d", seqno, transaction);
|
|
|
|
// Loop until there aren't any more priority messages to process.
|
|
for (;;) {
|
|
// If we canceled during ProcessPendingRequest, then we need to leave
|
|
// immediately because the results of ShouldDeferMessage will be
|
|
// operating with weird state (as if no Send is in progress). That could
|
|
// cause even normal priority sync messages to be processed (but not
|
|
// normal priority async messages), which would break message ordering.
|
|
if (WasTransactionCanceled(transaction)) {
|
|
return;
|
|
}
|
|
|
|
mozilla::Vector<Message> toProcess;
|
|
|
|
for (MessageQueue::iterator it = mPending.begin(); it != mPending.end(); ) {
|
|
Message &msg = *it;
|
|
|
|
MOZ_ASSERT(mCurrentTransaction == transaction,
|
|
"Calling ShouldDeferMessage when cancelled");
|
|
bool defer = ShouldDeferMessage(msg);
|
|
|
|
// Only log the interesting messages.
|
|
if (msg.is_sync() || msg.priority() == IPC::Message::PRIORITY_URGENT) {
|
|
IPC_LOG("ShouldDeferMessage(seqno=%d) = %d", msg.seqno(), defer);
|
|
}
|
|
|
|
if (!defer) {
|
|
toProcess.append(Move(msg));
|
|
it = mPending.erase(it);
|
|
continue;
|
|
}
|
|
it++;
|
|
}
|
|
|
|
if (toProcess.empty())
|
|
break;
|
|
|
|
// Processing these messages could result in more messages, so we
|
|
// loop around to check for more afterwards.
|
|
|
|
for (auto it = toProcess.begin(); it != toProcess.end(); it++)
|
|
ProcessPendingRequest(*it);
|
|
}
|
|
}
|
|
|
|
bool
|
|
MessageChannel::WasTransactionCanceled(int transaction)
|
|
{
|
|
if (transaction != mCurrentTransaction) {
|
|
// Imagine this scenario:
|
|
// 1. Child sends high prio sync message H1.
|
|
// 2. Parent sends reply to H1.
|
|
// 3. Parent sends high prio sync message H2.
|
|
// 4. Child's link thread receives H1 reply and H2 before worker wakes up.
|
|
// 5. Child dispatches H2 while still waiting for H1 reply.
|
|
// 6. Child cancels H2.
|
|
//
|
|
// In this case H1 will also be considered cancelled. However, its
|
|
// reply is still sitting in mRecvd, which can trip up later Sends. So
|
|
// we null it out here.
|
|
mRecvd = nullptr;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool
|
|
MessageChannel::Send(Message* aMsg, Message* aReply)
|
|
{
|
|
nsAutoPtr<Message> msg(aMsg);
|
|
|
|
// See comment in DispatchSyncMessage.
|
|
MaybeScriptBlocker scriptBlocker(this, true);
|
|
|
|
// Sanity checks.
|
|
AssertWorkerThread();
|
|
mMonitor->AssertNotCurrentThreadOwns();
|
|
|
|
#ifdef OS_WIN
|
|
SyncStackFrame frame(this, false);
|
|
NeuteredWindowRegion neuteredRgn(mFlags & REQUIRE_DEFERRED_MESSAGE_PROTECTION);
|
|
#endif
|
|
|
|
CxxStackFrame f(*this, OUT_MESSAGE, msg);
|
|
|
|
MonitorAutoLock lock(*mMonitor);
|
|
|
|
if (mTimedOutMessageSeqno) {
|
|
// Don't bother sending another sync message if a previous one timed out
|
|
// and we haven't received a reply for it. Once the original timed-out
|
|
// message receives a reply, we'll be able to send more sync messages
|
|
// again.
|
|
IPC_LOG("Send() failed due to previous timeout");
|
|
mLastSendError = SyncSendError::PreviousTimeout;
|
|
return false;
|
|
}
|
|
|
|
if (mCurrentTransaction &&
|
|
DispatchingSyncMessagePriority() == IPC::Message::PRIORITY_NORMAL &&
|
|
msg->priority() > IPC::Message::PRIORITY_NORMAL)
|
|
{
|
|
// Don't allow sending CPOWs while we're dispatching a sync message.
|
|
// If you want to do that, use sendRpcMessage instead.
|
|
IPC_LOG("Prio forbids send");
|
|
mLastSendError = SyncSendError::SendingCPOWWhileDispatchingSync;
|
|
return false;
|
|
}
|
|
|
|
if (mCurrentTransaction &&
|
|
(DispatchingSyncMessagePriority() == IPC::Message::PRIORITY_URGENT ||
|
|
DispatchingAsyncMessagePriority() == IPC::Message::PRIORITY_URGENT))
|
|
{
|
|
// Generally only the parent dispatches urgent messages. And the only
|
|
// sync messages it can send are high-priority. Mainly we want to ensure
|
|
// here that we don't return false for non-CPOW messages.
|
|
MOZ_ASSERT(msg->priority() == IPC::Message::PRIORITY_HIGH);
|
|
IPC_LOG("Sending while dispatching urgent message");
|
|
mLastSendError = SyncSendError::SendingCPOWWhileDispatchingUrgent;
|
|
return false;
|
|
}
|
|
|
|
if (mCurrentTransaction &&
|
|
(msg->priority() < DispatchingSyncMessagePriority() ||
|
|
msg->priority() < AwaitingSyncReplyPriority()))
|
|
{
|
|
MOZ_ASSERT(DispatchingSyncMessage() || DispatchingAsyncMessage());
|
|
IPC_LOG("Cancel from Send");
|
|
CancelMessage *cancel = new CancelMessage(mCurrentTransaction);
|
|
CancelTransaction(mCurrentTransaction);
|
|
mLink->SendMessage(cancel);
|
|
}
|
|
|
|
IPC_ASSERT(msg->is_sync(), "can only Send() sync messages here");
|
|
|
|
if (mCurrentTransaction) {
|
|
IPC_ASSERT(msg->priority() >= DispatchingSyncMessagePriority(),
|
|
"can't send sync message of a lesser priority than what's being dispatched");
|
|
IPC_ASSERT(AwaitingSyncReplyPriority() <= msg->priority(),
|
|
"nested sync message sends must be of increasing priority");
|
|
IPC_ASSERT(DispatchingSyncMessagePriority() != IPC::Message::PRIORITY_URGENT,
|
|
"not allowed to send messages while dispatching urgent messages");
|
|
}
|
|
|
|
IPC_ASSERT(DispatchingAsyncMessagePriority() != IPC::Message::PRIORITY_URGENT,
|
|
"not allowed to send messages while dispatching urgent messages");
|
|
|
|
if (!Connected()) {
|
|
ReportConnectionError("MessageChannel::SendAndWait", msg);
|
|
mLastSendError = SyncSendError::NotConnectedBeforeSend;
|
|
return false;
|
|
}
|
|
|
|
msg->set_seqno(NextSeqno());
|
|
|
|
int32_t seqno = msg->seqno();
|
|
int prio = msg->priority();
|
|
DebugOnly<msgid_t> replyType = msg->type() + 1;
|
|
|
|
AutoSetValue<bool> replies(mAwaitingSyncReply, true);
|
|
AutoSetValue<int> prioSet(mAwaitingSyncReplyPriority, prio);
|
|
AutoEnterTransaction transact(this, seqno);
|
|
|
|
int prios = mPendingSendPriorities | (1 << prio);
|
|
AutoSetValue<int> priosSet(mPendingSendPriorities, prios);
|
|
|
|
int32_t transaction = mCurrentTransaction;
|
|
msg->set_transaction_id(transaction);
|
|
|
|
IPC_LOG("Send seqno=%d, xid=%d, pending=%d", seqno, transaction, prios);
|
|
|
|
bool handleWindowsMessages = mListener->HandleWindowsMessages(*aMsg);
|
|
mLink->SendMessage(msg.forget());
|
|
|
|
while (true) {
|
|
ProcessPendingRequests(seqno, transaction);
|
|
if (WasTransactionCanceled(transaction)) {
|
|
IPC_LOG("Other side canceled seqno=%d, xid=%d", seqno, transaction);
|
|
mLastSendError = SyncSendError::CancelledAfterSend;
|
|
return false;
|
|
}
|
|
if (!Connected()) {
|
|
ReportConnectionError("MessageChannel::Send");
|
|
mLastSendError = SyncSendError::DisconnectedDuringSend;
|
|
return false;
|
|
}
|
|
|
|
// See if we've received a reply.
|
|
if (mRecvdErrors) {
|
|
IPC_LOG("Error: seqno=%d, xid=%d", seqno, transaction);
|
|
mRecvdErrors--;
|
|
mLastSendError = SyncSendError::ReplyError;
|
|
return false;
|
|
}
|
|
|
|
if (mRecvd) {
|
|
IPC_LOG("Got reply: seqno=%d, xid=%d", seqno, transaction);
|
|
break;
|
|
}
|
|
|
|
MOZ_ASSERT(!mTimedOutMessageSeqno);
|
|
|
|
MOZ_ASSERT(mCurrentTransaction == transaction);
|
|
bool maybeTimedOut = !WaitForSyncNotify(handleWindowsMessages);
|
|
|
|
if (!Connected()) {
|
|
ReportConnectionError("MessageChannel::SendAndWait");
|
|
mLastSendError = SyncSendError::DisconnectedDuringSend;
|
|
return false;
|
|
}
|
|
|
|
if (WasTransactionCanceled(transaction)) {
|
|
IPC_LOG("Other side canceled seqno=%d, xid=%d", seqno, transaction);
|
|
mLastSendError = SyncSendError::CancelledAfterSend;
|
|
return false;
|
|
}
|
|
|
|
// We only time out a message if it initiated a new transaction (i.e.,
|
|
// if neither side has any other message Sends on the stack).
|
|
bool canTimeOut = transaction == seqno;
|
|
if (maybeTimedOut && canTimeOut && !ShouldContinueFromTimeout()) {
|
|
// Since ShouldContinueFromTimeout drops the lock, we need to
|
|
// re-check all our conditions here. We shouldn't time out if any of
|
|
// these things happen because there won't be a reply to the timed
|
|
// out message in these cases.
|
|
if (WasTransactionCanceled(transaction)) {
|
|
IPC_LOG("Other side canceled seqno=%d, xid=%d", seqno, transaction);
|
|
mLastSendError = SyncSendError::CancelledAfterSend;
|
|
return false;
|
|
}
|
|
if (mRecvdErrors) {
|
|
mRecvdErrors--;
|
|
mLastSendError = SyncSendError::ReplyError;
|
|
return false;
|
|
}
|
|
if (mRecvd) {
|
|
break;
|
|
}
|
|
|
|
IPC_LOG("Timing out Send: xid=%d", transaction);
|
|
|
|
mTimedOutMessageSeqno = seqno;
|
|
mTimedOutMessagePriority = prio;
|
|
mLastSendError = SyncSendError::TimedOut;
|
|
return false;
|
|
}
|
|
}
|
|
|
|
MOZ_ASSERT(mRecvd);
|
|
MOZ_ASSERT(mRecvd->is_reply(), "expected reply");
|
|
MOZ_ASSERT(!mRecvd->is_reply_error());
|
|
MOZ_ASSERT(mRecvd->type() == replyType, "wrong reply type");
|
|
MOZ_ASSERT(mRecvd->seqno() == seqno);
|
|
MOZ_ASSERT(mRecvd->is_sync());
|
|
|
|
*aReply = Move(*mRecvd);
|
|
mRecvd = nullptr;
|
|
mLastSendError = SyncSendError::SendSuccess;
|
|
return true;
|
|
}
|
|
|
|
bool
|
|
MessageChannel::Call(Message* aMsg, Message* aReply)
|
|
{
|
|
nsAutoPtr<Message> msg(aMsg);
|
|
AssertWorkerThread();
|
|
mMonitor->AssertNotCurrentThreadOwns();
|
|
|
|
#ifdef OS_WIN
|
|
SyncStackFrame frame(this, true);
|
|
#endif
|
|
|
|
// This must come before MonitorAutoLock, as its destructor acquires the
|
|
// monitor lock.
|
|
CxxStackFrame cxxframe(*this, OUT_MESSAGE, msg);
|
|
|
|
MonitorAutoLock lock(*mMonitor);
|
|
if (!Connected()) {
|
|
ReportConnectionError("MessageChannel::Call", msg);
|
|
return false;
|
|
}
|
|
|
|
// Sanity checks.
|
|
IPC_ASSERT(!AwaitingSyncReply(),
|
|
"cannot issue Interrupt call while blocked on sync request");
|
|
IPC_ASSERT(!DispatchingSyncMessage(),
|
|
"violation of sync handler invariant");
|
|
IPC_ASSERT(msg->is_interrupt(), "can only Call() Interrupt messages here");
|
|
|
|
msg->set_seqno(NextSeqno());
|
|
msg->set_interrupt_remote_stack_depth_guess(mRemoteStackDepthGuess);
|
|
msg->set_interrupt_local_stack_depth(1 + InterruptStackDepth());
|
|
mInterruptStack.push(*msg);
|
|
mLink->SendMessage(msg.forget());
|
|
|
|
while (true) {
|
|
// if a handler invoked by *Dispatch*() spun a nested event
|
|
// loop, and the connection was broken during that loop, we
|
|
// might have already processed the OnError event. if so,
|
|
// trying another loop iteration will be futile because
|
|
// channel state will have been cleared
|
|
if (!Connected()) {
|
|
ReportConnectionError("MessageChannel::Call");
|
|
return false;
|
|
}
|
|
|
|
#ifdef OS_WIN
|
|
// We need to limit the scoped of neuteredRgn to this spot in the code.
|
|
// Window neutering can't be enabled during some plugin calls because
|
|
// we then risk the neutered window procedure being subclassed by a
|
|
// plugin.
|
|
{
|
|
NeuteredWindowRegion neuteredRgn(mFlags & REQUIRE_DEFERRED_MESSAGE_PROTECTION);
|
|
/* We should pump messages at this point to ensure that the IPC peer
|
|
does not become deadlocked on a pending inter-thread SendMessage() */
|
|
neuteredRgn.PumpOnce();
|
|
}
|
|
#endif
|
|
|
|
// Now might be the time to process a message deferred because of race
|
|
// resolution.
|
|
MaybeUndeferIncall();
|
|
|
|
// Wait for an event to occur.
|
|
while (!InterruptEventOccurred()) {
|
|
bool maybeTimedOut = !WaitForInterruptNotify();
|
|
|
|
// We might have received a "subtly deferred" message in a nested
|
|
// loop that it's now time to process.
|
|
if (InterruptEventOccurred() ||
|
|
(!maybeTimedOut && (!mDeferred.empty() || !mOutOfTurnReplies.empty())))
|
|
{
|
|
break;
|
|
}
|
|
|
|
if (maybeTimedOut && !ShouldContinueFromTimeout())
|
|
return false;
|
|
}
|
|
|
|
Message recvd;
|
|
MessageMap::iterator it;
|
|
|
|
if ((it = mOutOfTurnReplies.find(mInterruptStack.top().seqno()))
|
|
!= mOutOfTurnReplies.end())
|
|
{
|
|
recvd = Move(it->second);
|
|
mOutOfTurnReplies.erase(it);
|
|
} else if (!mPending.empty()) {
|
|
recvd = Move(mPending.front());
|
|
mPending.pop_front();
|
|
} else {
|
|
// because of subtleties with nested event loops, it's possible
|
|
// that we got here and nothing happened. or, we might have a
|
|
// deferred in-call that needs to be processed. either way, we
|
|
// won't break the inner while loop again until something new
|
|
// happens.
|
|
continue;
|
|
}
|
|
|
|
// If the message is not Interrupt, we can dispatch it as normal.
|
|
if (!recvd.is_interrupt()) {
|
|
DispatchMessage(recvd);
|
|
if (!Connected()) {
|
|
ReportConnectionError("MessageChannel::DispatchMessage");
|
|
return false;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
// If the message is an Interrupt reply, either process it as a reply to our
|
|
// call, or add it to the list of out-of-turn replies we've received.
|
|
if (recvd.is_reply()) {
|
|
IPC_ASSERT(!mInterruptStack.empty(), "invalid Interrupt stack");
|
|
|
|
// If this is not a reply the call we've initiated, add it to our
|
|
// out-of-turn replies and keep polling for events.
|
|
{
|
|
const Message &outcall = mInterruptStack.top();
|
|
|
|
// Note, In the parent, sequence numbers increase from 0, and
|
|
// in the child, they decrease from 0.
|
|
if ((mSide == ChildSide && recvd.seqno() > outcall.seqno()) ||
|
|
(mSide != ChildSide && recvd.seqno() < outcall.seqno()))
|
|
{
|
|
mOutOfTurnReplies[recvd.seqno()] = Move(recvd);
|
|
continue;
|
|
}
|
|
|
|
IPC_ASSERT(recvd.is_reply_error() ||
|
|
(recvd.type() == (outcall.type() + 1) &&
|
|
recvd.seqno() == outcall.seqno()),
|
|
"somebody's misbehavin'", true);
|
|
}
|
|
|
|
// We received a reply to our most recent outstanding call. Pop
|
|
// this frame and return the reply.
|
|
mInterruptStack.pop();
|
|
|
|
bool is_reply_error = recvd.is_reply_error();
|
|
if (!is_reply_error) {
|
|
*aReply = Move(recvd);
|
|
}
|
|
|
|
// If we have no more pending out calls waiting on replies, then
|
|
// the reply queue should be empty.
|
|
IPC_ASSERT(!mInterruptStack.empty() || mOutOfTurnReplies.empty(),
|
|
"still have pending replies with no pending out-calls",
|
|
true);
|
|
|
|
return !is_reply_error;
|
|
}
|
|
|
|
// Dispatch an Interrupt in-call. Snapshot the current stack depth while we
|
|
// own the monitor.
|
|
size_t stackDepth = InterruptStackDepth();
|
|
{
|
|
MonitorAutoUnlock unlock(*mMonitor);
|
|
|
|
CxxStackFrame frame(*this, IN_MESSAGE, &recvd);
|
|
DispatchInterruptMessage(recvd, stackDepth);
|
|
}
|
|
if (!Connected()) {
|
|
ReportConnectionError("MessageChannel::DispatchInterruptMessage");
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
bool
|
|
MessageChannel::WaitForIncomingMessage()
|
|
{
|
|
#ifdef OS_WIN
|
|
SyncStackFrame frame(this, true);
|
|
NeuteredWindowRegion neuteredRgn(mFlags & REQUIRE_DEFERRED_MESSAGE_PROTECTION);
|
|
#endif
|
|
|
|
{ // Scope for lock
|
|
MonitorAutoLock lock(*mMonitor);
|
|
AutoEnterWaitForIncoming waitingForIncoming(*this);
|
|
if (mChannelState != ChannelConnected) {
|
|
return false;
|
|
}
|
|
if (!HasPendingEvents()) {
|
|
return WaitForInterruptNotify();
|
|
}
|
|
}
|
|
|
|
return OnMaybeDequeueOne();
|
|
}
|
|
|
|
bool
|
|
MessageChannel::HasPendingEvents()
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
return Connected() && !mPending.empty();
|
|
}
|
|
|
|
bool
|
|
MessageChannel::InterruptEventOccurred()
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
IPC_ASSERT(InterruptStackDepth() > 0, "not in wait loop");
|
|
|
|
return (!Connected() ||
|
|
!mPending.empty() ||
|
|
(!mOutOfTurnReplies.empty() &&
|
|
mOutOfTurnReplies.find(mInterruptStack.top().seqno()) !=
|
|
mOutOfTurnReplies.end()));
|
|
}
|
|
|
|
bool
|
|
MessageChannel::ProcessPendingRequest(const Message &aUrgent)
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
|
|
// Note that it is possible we could have sent a sync message at
|
|
// the same time the parent process sent an urgent message, and
|
|
// therefore mPendingUrgentRequest is set *and* mRecvd is set as
|
|
// well, because the link thread received both before the worker
|
|
// thread woke up.
|
|
//
|
|
// In this case, we process the urgent message first, but we need
|
|
// to save the reply.
|
|
nsAutoPtr<Message> savedReply(mRecvd.forget());
|
|
|
|
IPC_LOG("Process pending: seqno=%d, xid=%d", aUrgent.seqno(), aUrgent.transaction_id());
|
|
|
|
DispatchMessage(aUrgent);
|
|
if (!Connected()) {
|
|
ReportConnectionError("MessageChannel::ProcessPendingRequest");
|
|
return false;
|
|
}
|
|
|
|
// In between having dispatched our reply to the parent process, and
|
|
// re-acquiring the monitor, the parent process could have already
|
|
// processed that reply and sent the reply to our sync message. If so,
|
|
// our saved reply should be empty.
|
|
IPC_ASSERT(!mRecvd || !savedReply, "unknown reply");
|
|
if (!mRecvd)
|
|
mRecvd = savedReply.forget();
|
|
return true;
|
|
}
|
|
|
|
bool
|
|
MessageChannel::DequeueOne(Message *recvd)
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
|
|
if (!Connected()) {
|
|
ReportConnectionError("OnMaybeDequeueOne");
|
|
return false;
|
|
}
|
|
|
|
if (!mDeferred.empty())
|
|
MaybeUndeferIncall();
|
|
|
|
// If we've timed out a message and we're awaiting the reply to the timed
|
|
// out message, we have to be careful what messages we process. Here's what
|
|
// can go wrong:
|
|
// 1. child sends a normal priority sync message S
|
|
// 2. parent sends a high priority sync message H at the same time
|
|
// 3. parent times out H
|
|
// 4. child starts processing H and sends a high priority message H' nested
|
|
// within the same transaction
|
|
// 5. parent dispatches S and sends reply
|
|
// 6. child asserts because it instead expected a reply to H'.
|
|
//
|
|
// To solve this, we refuse to process S in the parent until we get a reply
|
|
// to H. More generally, let the timed out message be M. We don't process a
|
|
// message unless the child would need the response to that message in order
|
|
// to process M. Those messages are the ones that have a higher priority
|
|
// than M or that are part of the same transaction as M.
|
|
if (mTimedOutMessageSeqno) {
|
|
for (MessageQueue::iterator it = mPending.begin(); it != mPending.end(); it++) {
|
|
Message &msg = *it;
|
|
if (msg.priority() > mTimedOutMessagePriority ||
|
|
(msg.priority() == mTimedOutMessagePriority
|
|
&& msg.transaction_id() == mTimedOutMessageSeqno))
|
|
{
|
|
*recvd = Move(msg);
|
|
mPending.erase(it);
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
if (mPending.empty())
|
|
return false;
|
|
|
|
*recvd = Move(mPending.front());
|
|
mPending.pop_front();
|
|
return true;
|
|
}
|
|
|
|
bool
|
|
MessageChannel::OnMaybeDequeueOne()
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertNotCurrentThreadOwns();
|
|
|
|
Message recvd;
|
|
|
|
MonitorAutoLock lock(*mMonitor);
|
|
if (!DequeueOne(&recvd))
|
|
return false;
|
|
|
|
if (IsOnCxxStack() && recvd.is_interrupt() && recvd.is_reply()) {
|
|
// We probably just received a reply in a nested loop for an
|
|
// Interrupt call sent before entering that loop.
|
|
mOutOfTurnReplies[recvd.seqno()] = Move(recvd);
|
|
return false;
|
|
}
|
|
|
|
// We should not be in a transaction yet if we're not blocked.
|
|
MOZ_ASSERT(mCurrentTransaction == 0);
|
|
DispatchMessage(recvd);
|
|
|
|
return true;
|
|
}
|
|
|
|
void
|
|
MessageChannel::DispatchMessage(const Message &aMsg)
|
|
{
|
|
Maybe<AutoNoJSAPI> nojsapi;
|
|
if (ScriptSettingsInitialized() && NS_IsMainThread())
|
|
nojsapi.emplace();
|
|
|
|
nsAutoPtr<Message> reply;
|
|
|
|
IPC_LOG("DispatchMessage: seqno=%d, xid=%d", aMsg.seqno(), aMsg.transaction_id());
|
|
|
|
{
|
|
AutoEnterTransaction transaction(this, aMsg);
|
|
|
|
int id = aMsg.transaction_id();
|
|
MOZ_ASSERT_IF(aMsg.is_sync(), id == mCurrentTransaction);
|
|
|
|
{
|
|
MonitorAutoUnlock unlock(*mMonitor);
|
|
CxxStackFrame frame(*this, IN_MESSAGE, &aMsg);
|
|
|
|
if (aMsg.is_sync())
|
|
DispatchSyncMessage(aMsg, *getter_Transfers(reply));
|
|
else if (aMsg.is_interrupt())
|
|
DispatchInterruptMessage(aMsg, 0);
|
|
else
|
|
DispatchAsyncMessage(aMsg);
|
|
}
|
|
|
|
if (mCurrentTransaction != id) {
|
|
// The transaction has been canceled. Don't send a reply.
|
|
reply = nullptr;
|
|
}
|
|
}
|
|
|
|
if (reply && ChannelConnected == mChannelState) {
|
|
mLink->SendMessage(reply.forget());
|
|
}
|
|
}
|
|
|
|
void
|
|
MessageChannel::DispatchSyncMessage(const Message& aMsg, Message*& aReply)
|
|
{
|
|
AssertWorkerThread();
|
|
|
|
int prio = aMsg.priority();
|
|
|
|
// We don't want to run any code that might run a nested event loop here, so
|
|
// we avoid running event handlers. Once we've sent the response to the
|
|
// urgent message, it's okay to run event handlers again since the parent is
|
|
// no longer blocked.
|
|
MOZ_ASSERT_IF(prio > IPC::Message::PRIORITY_NORMAL, NS_IsMainThread());
|
|
MaybeScriptBlocker scriptBlocker(this, prio > IPC::Message::PRIORITY_NORMAL);
|
|
|
|
MessageChannel* dummy;
|
|
MessageChannel*& blockingVar = ShouldBlockScripts() ? gParentProcessBlocker : dummy;
|
|
|
|
Result rv;
|
|
{
|
|
AutoSetValue<MessageChannel*> blocked(blockingVar, this);
|
|
AutoSetValue<bool> sync(mDispatchingSyncMessage, true);
|
|
AutoSetValue<int> prioSet(mDispatchingSyncMessagePriority, prio);
|
|
rv = mListener->OnMessageReceived(aMsg, aReply);
|
|
}
|
|
|
|
if (!MaybeHandleError(rv, aMsg, "DispatchSyncMessage")) {
|
|
aReply = new Message();
|
|
aReply->set_sync();
|
|
aReply->set_priority(aMsg.priority());
|
|
aReply->set_reply();
|
|
aReply->set_reply_error();
|
|
}
|
|
aReply->set_seqno(aMsg.seqno());
|
|
aReply->set_transaction_id(aMsg.transaction_id());
|
|
}
|
|
|
|
void
|
|
MessageChannel::DispatchAsyncMessage(const Message& aMsg)
|
|
{
|
|
AssertWorkerThread();
|
|
MOZ_ASSERT(!aMsg.is_interrupt() && !aMsg.is_sync());
|
|
|
|
if (aMsg.routing_id() == MSG_ROUTING_NONE) {
|
|
NS_RUNTIMEABORT("unhandled special message!");
|
|
}
|
|
|
|
Result rv;
|
|
{
|
|
int prio = aMsg.priority();
|
|
AutoSetValue<bool> async(mDispatchingAsyncMessage, true);
|
|
AutoSetValue<int> prioSet(mDispatchingAsyncMessagePriority, prio);
|
|
rv = mListener->OnMessageReceived(aMsg);
|
|
}
|
|
MaybeHandleError(rv, aMsg, "DispatchAsyncMessage");
|
|
}
|
|
|
|
void
|
|
MessageChannel::DispatchInterruptMessage(const Message& aMsg, size_t stackDepth)
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertNotCurrentThreadOwns();
|
|
|
|
IPC_ASSERT(aMsg.is_interrupt() && !aMsg.is_reply(), "wrong message type");
|
|
|
|
// Race detection: see the long comment near mRemoteStackDepthGuess in
|
|
// MessageChannel.h. "Remote" stack depth means our side, and "local" means
|
|
// the other side.
|
|
if (aMsg.interrupt_remote_stack_depth_guess() != RemoteViewOfStackDepth(stackDepth)) {
|
|
// Interrupt in-calls have raced. The winner, if there is one, gets to defer
|
|
// processing of the other side's in-call.
|
|
bool defer;
|
|
const char* winner;
|
|
const Message& parentMsg = (mSide == ChildSide) ? aMsg : mInterruptStack.top();
|
|
const Message& childMsg = (mSide == ChildSide) ? mInterruptStack.top() : aMsg;
|
|
switch (mListener->MediateInterruptRace(parentMsg, childMsg))
|
|
{
|
|
case RIPChildWins:
|
|
winner = "child";
|
|
defer = (mSide == ChildSide);
|
|
break;
|
|
case RIPParentWins:
|
|
winner = "parent";
|
|
defer = (mSide != ChildSide);
|
|
break;
|
|
case RIPError:
|
|
NS_RUNTIMEABORT("NYI: 'Error' Interrupt race policy");
|
|
return;
|
|
default:
|
|
NS_RUNTIMEABORT("not reached");
|
|
return;
|
|
}
|
|
|
|
if (LoggingEnabled()) {
|
|
printf_stderr(" (%s: %s won, so we're%sdeferring)\n",
|
|
(mSide == ChildSide) ? "child" : "parent",
|
|
winner,
|
|
defer ? " " : " not ");
|
|
}
|
|
|
|
if (defer) {
|
|
// We now know the other side's stack has one more frame
|
|
// than we thought.
|
|
++mRemoteStackDepthGuess; // decremented in MaybeProcessDeferred()
|
|
mDeferred.push(aMsg);
|
|
return;
|
|
}
|
|
|
|
// We "lost" and need to process the other side's in-call. Don't need
|
|
// to fix up the mRemoteStackDepthGuess here, because we're just about
|
|
// to increment it in DispatchCall(), which will make it correct again.
|
|
}
|
|
|
|
#ifdef OS_WIN
|
|
SyncStackFrame frame(this, true);
|
|
#endif
|
|
|
|
nsAutoPtr<Message> reply;
|
|
|
|
++mRemoteStackDepthGuess;
|
|
Result rv = mListener->OnCallReceived(aMsg, *getter_Transfers(reply));
|
|
--mRemoteStackDepthGuess;
|
|
|
|
if (!MaybeHandleError(rv, aMsg, "DispatchInterruptMessage")) {
|
|
reply = new Message();
|
|
reply->set_interrupt();
|
|
reply->set_reply();
|
|
reply->set_reply_error();
|
|
}
|
|
reply->set_seqno(aMsg.seqno());
|
|
|
|
MonitorAutoLock lock(*mMonitor);
|
|
if (ChannelConnected == mChannelState) {
|
|
mLink->SendMessage(reply.forget());
|
|
}
|
|
}
|
|
|
|
void
|
|
MessageChannel::MaybeUndeferIncall()
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
|
|
if (mDeferred.empty())
|
|
return;
|
|
|
|
size_t stackDepth = InterruptStackDepth();
|
|
|
|
// the other side can only *under*-estimate our actual stack depth
|
|
IPC_ASSERT(mDeferred.top().interrupt_remote_stack_depth_guess() <= stackDepth,
|
|
"fatal logic error");
|
|
|
|
// maybe time to process this message
|
|
Message call = mDeferred.top();
|
|
mDeferred.pop();
|
|
|
|
// fix up fudge factor we added to account for race
|
|
IPC_ASSERT(0 < mRemoteStackDepthGuess, "fatal logic error");
|
|
--mRemoteStackDepthGuess;
|
|
|
|
MOZ_ASSERT(call.priority() == IPC::Message::PRIORITY_NORMAL);
|
|
mPending.push_back(call);
|
|
}
|
|
|
|
void
|
|
MessageChannel::FlushPendingInterruptQueue()
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertNotCurrentThreadOwns();
|
|
|
|
{
|
|
MonitorAutoLock lock(*mMonitor);
|
|
|
|
if (mDeferred.empty()) {
|
|
if (mPending.empty())
|
|
return;
|
|
|
|
const Message& last = mPending.back();
|
|
if (!last.is_interrupt() || last.is_reply())
|
|
return;
|
|
}
|
|
}
|
|
|
|
while (OnMaybeDequeueOne());
|
|
}
|
|
|
|
void
|
|
MessageChannel::ExitedCxxStack()
|
|
{
|
|
mListener->OnExitedCxxStack();
|
|
if (mSawInterruptOutMsg) {
|
|
MonitorAutoLock lock(*mMonitor);
|
|
// see long comment in OnMaybeDequeueOne()
|
|
EnqueuePendingMessages();
|
|
mSawInterruptOutMsg = false;
|
|
}
|
|
}
|
|
|
|
void
|
|
MessageChannel::EnqueuePendingMessages()
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
|
|
MaybeUndeferIncall();
|
|
|
|
for (size_t i = 0; i < mDeferred.size(); ++i) {
|
|
mWorkerLoop->PostTask(FROM_HERE, new DequeueTask(mDequeueOneTask));
|
|
}
|
|
|
|
// XXX performance tuning knob: could process all or k pending
|
|
// messages here, rather than enqueuing for later processing
|
|
|
|
for (size_t i = 0; i < mPending.size(); ++i) {
|
|
mWorkerLoop->PostTask(FROM_HERE, new DequeueTask(mDequeueOneTask));
|
|
}
|
|
}
|
|
|
|
static inline bool
|
|
IsTimeoutExpired(PRIntervalTime aStart, PRIntervalTime aTimeout)
|
|
{
|
|
return (aTimeout != PR_INTERVAL_NO_TIMEOUT) &&
|
|
(aTimeout <= (PR_IntervalNow() - aStart));
|
|
}
|
|
|
|
bool
|
|
MessageChannel::WaitResponse(bool aWaitTimedOut)
|
|
{
|
|
if (aWaitTimedOut) {
|
|
if (mInTimeoutSecondHalf) {
|
|
// We've really timed out this time.
|
|
return false;
|
|
}
|
|
// Try a second time.
|
|
mInTimeoutSecondHalf = true;
|
|
} else {
|
|
mInTimeoutSecondHalf = false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
#ifndef OS_WIN
|
|
bool
|
|
MessageChannel::WaitForSyncNotify(bool /* aHandleWindowsMessages */)
|
|
{
|
|
PRIntervalTime timeout = (kNoTimeout == mTimeoutMs) ?
|
|
PR_INTERVAL_NO_TIMEOUT :
|
|
PR_MillisecondsToInterval(mTimeoutMs);
|
|
// XXX could optimize away this syscall for "no timeout" case if desired
|
|
PRIntervalTime waitStart = PR_IntervalNow();
|
|
|
|
mMonitor->Wait(timeout);
|
|
|
|
// If the timeout didn't expire, we know we received an event. The
|
|
// converse is not true.
|
|
return WaitResponse(IsTimeoutExpired(waitStart, timeout));
|
|
}
|
|
|
|
bool
|
|
MessageChannel::WaitForInterruptNotify()
|
|
{
|
|
return WaitForSyncNotify(true);
|
|
}
|
|
|
|
void
|
|
MessageChannel::NotifyWorkerThread()
|
|
{
|
|
mMonitor->Notify();
|
|
}
|
|
#endif
|
|
|
|
bool
|
|
MessageChannel::ShouldContinueFromTimeout()
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
|
|
bool cont;
|
|
{
|
|
MonitorAutoUnlock unlock(*mMonitor);
|
|
cont = mListener->OnReplyTimeout();
|
|
}
|
|
|
|
static enum { UNKNOWN, NOT_DEBUGGING, DEBUGGING } sDebuggingChildren = UNKNOWN;
|
|
|
|
if (sDebuggingChildren == UNKNOWN) {
|
|
sDebuggingChildren = getenv("MOZ_DEBUG_CHILD_PROCESS") ? DEBUGGING : NOT_DEBUGGING;
|
|
}
|
|
if (sDebuggingChildren == DEBUGGING) {
|
|
return true;
|
|
}
|
|
|
|
return cont;
|
|
}
|
|
|
|
void
|
|
MessageChannel::SetReplyTimeoutMs(int32_t aTimeoutMs)
|
|
{
|
|
// Set channel timeout value. Since this is broken up into
|
|
// two period, the minimum timeout value is 2ms.
|
|
AssertWorkerThread();
|
|
mTimeoutMs = (aTimeoutMs <= 0)
|
|
? kNoTimeout
|
|
: (int32_t)ceil((double)aTimeoutMs / 2.0);
|
|
}
|
|
|
|
void
|
|
MessageChannel::OnChannelConnected(int32_t peer_id)
|
|
{
|
|
MOZ_ASSERT(!mPeerPidSet);
|
|
mPeerPidSet = true;
|
|
mPeerPid = peer_id;
|
|
mWorkerLoop->PostTask(FROM_HERE, new DequeueTask(mOnChannelConnectedTask));
|
|
}
|
|
|
|
void
|
|
MessageChannel::DispatchOnChannelConnected()
|
|
{
|
|
AssertWorkerThread();
|
|
MOZ_ASSERT(mPeerPidSet);
|
|
if (mListener)
|
|
mListener->OnChannelConnected(mPeerPid);
|
|
}
|
|
|
|
void
|
|
MessageChannel::ReportMessageRouteError(const char* channelName) const
|
|
{
|
|
PrintErrorMessage(mSide, channelName, "Need a route");
|
|
mListener->OnProcessingError(MsgRouteError, "MsgRouteError");
|
|
}
|
|
|
|
void
|
|
MessageChannel::ReportConnectionError(const char* aChannelName, Message* aMsg) const
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
|
|
const char* errorMsg = nullptr;
|
|
switch (mChannelState) {
|
|
case ChannelClosed:
|
|
errorMsg = "Closed channel: cannot send/recv";
|
|
break;
|
|
case ChannelOpening:
|
|
errorMsg = "Opening channel: not yet ready for send/recv";
|
|
break;
|
|
case ChannelTimeout:
|
|
errorMsg = "Channel timeout: cannot send/recv";
|
|
break;
|
|
case ChannelClosing:
|
|
errorMsg = "Channel closing: too late to send/recv, messages will be lost";
|
|
break;
|
|
case ChannelError:
|
|
errorMsg = "Channel error: cannot send/recv";
|
|
break;
|
|
|
|
default:
|
|
NS_RUNTIMEABORT("unreached");
|
|
}
|
|
|
|
if (aMsg) {
|
|
char reason[512];
|
|
PR_snprintf(reason, sizeof(reason),
|
|
"(msgtype=0x%lX,name=%s) %s",
|
|
aMsg->type(), aMsg->name(), errorMsg);
|
|
|
|
PrintErrorMessage(mSide, aChannelName, reason);
|
|
} else {
|
|
PrintErrorMessage(mSide, aChannelName, errorMsg);
|
|
}
|
|
|
|
MonitorAutoUnlock unlock(*mMonitor);
|
|
mListener->OnProcessingError(MsgDropped, errorMsg);
|
|
}
|
|
|
|
bool
|
|
MessageChannel::MaybeHandleError(Result code, const Message& aMsg, const char* channelName)
|
|
{
|
|
if (MsgProcessed == code)
|
|
return true;
|
|
|
|
const char* errorMsg = nullptr;
|
|
switch (code) {
|
|
case MsgNotKnown:
|
|
errorMsg = "Unknown message: not processed";
|
|
break;
|
|
case MsgNotAllowed:
|
|
errorMsg = "Message not allowed: cannot be sent/recvd in this state";
|
|
break;
|
|
case MsgPayloadError:
|
|
errorMsg = "Payload error: message could not be deserialized";
|
|
break;
|
|
case MsgProcessingError:
|
|
errorMsg = "Processing error: message was deserialized, but the handler returned false (indicating failure)";
|
|
break;
|
|
case MsgRouteError:
|
|
errorMsg = "Route error: message sent to unknown actor ID";
|
|
break;
|
|
case MsgValueError:
|
|
errorMsg = "Value error: message was deserialized, but contained an illegal value";
|
|
break;
|
|
|
|
default:
|
|
NS_RUNTIMEABORT("unknown Result code");
|
|
return false;
|
|
}
|
|
|
|
char reason[512];
|
|
PR_snprintf(reason, sizeof(reason),
|
|
"(msgtype=0x%lX,name=%s) %s",
|
|
aMsg.type(), aMsg.name(), errorMsg);
|
|
|
|
PrintErrorMessage(mSide, channelName, reason);
|
|
|
|
mListener->OnProcessingError(code, reason);
|
|
|
|
return false;
|
|
}
|
|
|
|
void
|
|
MessageChannel::OnChannelErrorFromLink()
|
|
{
|
|
AssertLinkThread();
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
|
|
IPC_LOG("OnChannelErrorFromLink");
|
|
|
|
if (InterruptStackDepth() > 0)
|
|
NotifyWorkerThread();
|
|
|
|
if (AwaitingSyncReply() || AwaitingIncomingMessage())
|
|
NotifyWorkerThread();
|
|
|
|
if (ChannelClosing != mChannelState) {
|
|
if (mAbortOnError) {
|
|
NS_RUNTIMEABORT("Aborting on channel error.");
|
|
}
|
|
mChannelState = ChannelError;
|
|
mMonitor->Notify();
|
|
}
|
|
|
|
PostErrorNotifyTask();
|
|
}
|
|
|
|
void
|
|
MessageChannel::NotifyMaybeChannelError()
|
|
{
|
|
mMonitor->AssertNotCurrentThreadOwns();
|
|
|
|
// TODO sort out Close() on this side racing with Close() on the other side
|
|
if (ChannelClosing == mChannelState) {
|
|
// the channel closed, but we received a "Goodbye" message warning us
|
|
// about it. no worries
|
|
mChannelState = ChannelClosed;
|
|
NotifyChannelClosed();
|
|
return;
|
|
}
|
|
|
|
// Oops, error! Let the listener know about it.
|
|
mChannelState = ChannelError;
|
|
mListener->OnChannelError();
|
|
Clear();
|
|
}
|
|
|
|
void
|
|
MessageChannel::OnNotifyMaybeChannelError()
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertNotCurrentThreadOwns();
|
|
|
|
mChannelErrorTask = nullptr;
|
|
|
|
// OnChannelError holds mMonitor when it posts this task and this
|
|
// task cannot be allowed to run until OnChannelError has
|
|
// exited. We enforce that order by grabbing the mutex here which
|
|
// should only continue once OnChannelError has completed.
|
|
{
|
|
MonitorAutoLock lock(*mMonitor);
|
|
// nothing to do here
|
|
}
|
|
|
|
if (IsOnCxxStack()) {
|
|
mChannelErrorTask =
|
|
NewRunnableMethod(this, &MessageChannel::OnNotifyMaybeChannelError);
|
|
// 10 ms delay is completely arbitrary
|
|
mWorkerLoop->PostDelayedTask(FROM_HERE, mChannelErrorTask, 10);
|
|
return;
|
|
}
|
|
|
|
NotifyMaybeChannelError();
|
|
}
|
|
|
|
void
|
|
MessageChannel::PostErrorNotifyTask()
|
|
{
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
|
|
if (mChannelErrorTask)
|
|
return;
|
|
|
|
// This must be the last code that runs on this thread!
|
|
mChannelErrorTask =
|
|
NewRunnableMethod(this, &MessageChannel::OnNotifyMaybeChannelError);
|
|
mWorkerLoop->PostTask(FROM_HERE, mChannelErrorTask);
|
|
}
|
|
|
|
// Special async message.
|
|
class GoodbyeMessage : public IPC::Message
|
|
{
|
|
public:
|
|
GoodbyeMessage() :
|
|
IPC::Message(MSG_ROUTING_NONE, GOODBYE_MESSAGE_TYPE, PRIORITY_NORMAL)
|
|
{
|
|
}
|
|
static bool Read(const Message* msg) {
|
|
return true;
|
|
}
|
|
void Log(const std::string& aPrefix, FILE* aOutf) const {
|
|
fputs("(special `Goodbye' message)", aOutf);
|
|
}
|
|
};
|
|
|
|
void
|
|
MessageChannel::SynchronouslyClose()
|
|
{
|
|
AssertWorkerThread();
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
mLink->SendClose();
|
|
while (ChannelClosed != mChannelState)
|
|
mMonitor->Wait();
|
|
}
|
|
|
|
void
|
|
MessageChannel::CloseWithError()
|
|
{
|
|
AssertWorkerThread();
|
|
|
|
MonitorAutoLock lock(*mMonitor);
|
|
if (ChannelConnected != mChannelState) {
|
|
return;
|
|
}
|
|
SynchronouslyClose();
|
|
mChannelState = ChannelError;
|
|
PostErrorNotifyTask();
|
|
}
|
|
|
|
void
|
|
MessageChannel::CloseWithTimeout()
|
|
{
|
|
AssertWorkerThread();
|
|
|
|
MonitorAutoLock lock(*mMonitor);
|
|
if (ChannelConnected != mChannelState) {
|
|
return;
|
|
}
|
|
SynchronouslyClose();
|
|
mChannelState = ChannelTimeout;
|
|
}
|
|
|
|
void
|
|
MessageChannel::BlockScripts()
|
|
{
|
|
MOZ_ASSERT(NS_IsMainThread());
|
|
mBlockScripts = true;
|
|
}
|
|
|
|
void
|
|
MessageChannel::Close()
|
|
{
|
|
AssertWorkerThread();
|
|
|
|
{
|
|
MonitorAutoLock lock(*mMonitor);
|
|
|
|
if (ChannelError == mChannelState || ChannelTimeout == mChannelState) {
|
|
// See bug 538586: if the listener gets deleted while the
|
|
// IO thread's NotifyChannelError event is still enqueued
|
|
// and subsequently deletes us, then the error event will
|
|
// also be deleted and the listener will never be notified
|
|
// of the channel error.
|
|
if (mListener) {
|
|
MonitorAutoUnlock unlock(*mMonitor);
|
|
NotifyMaybeChannelError();
|
|
}
|
|
return;
|
|
}
|
|
|
|
if (ChannelOpening == mChannelState) {
|
|
// SynchronouslyClose() waits for an ack from the other side, so
|
|
// the opening sequence should complete before this returns.
|
|
SynchronouslyClose();
|
|
mChannelState = ChannelError;
|
|
NotifyMaybeChannelError();
|
|
return;
|
|
}
|
|
|
|
if (ChannelConnected != mChannelState) {
|
|
// XXX be strict about this until there's a compelling reason
|
|
// to relax
|
|
NS_RUNTIMEABORT("Close() called on closed channel!");
|
|
}
|
|
|
|
// notify the other side that we're about to close our socket
|
|
mLink->SendMessage(new GoodbyeMessage());
|
|
SynchronouslyClose();
|
|
}
|
|
|
|
NotifyChannelClosed();
|
|
}
|
|
|
|
void
|
|
MessageChannel::NotifyChannelClosed()
|
|
{
|
|
mMonitor->AssertNotCurrentThreadOwns();
|
|
|
|
if (ChannelClosed != mChannelState)
|
|
NS_RUNTIMEABORT("channel should have been closed!");
|
|
|
|
// OK, the IO thread just closed the channel normally. Let the
|
|
// listener know about it.
|
|
mListener->OnChannelClose();
|
|
|
|
Clear();
|
|
}
|
|
|
|
void
|
|
MessageChannel::DebugAbort(const char* file, int line, const char* cond,
|
|
const char* why,
|
|
bool reply) const
|
|
{
|
|
printf_stderr("###!!! [MessageChannel][%s][%s:%d] "
|
|
"Assertion (%s) failed. %s %s\n",
|
|
mSide == ChildSide ? "Child" : "Parent",
|
|
file, line, cond,
|
|
why,
|
|
reply ? "(reply)" : "");
|
|
// technically we need the mutex for this, but we're dying anyway
|
|
DumpInterruptStack(" ");
|
|
printf_stderr(" remote Interrupt stack guess: %" PRIuSIZE "\n",
|
|
mRemoteStackDepthGuess);
|
|
printf_stderr(" deferred stack size: %" PRIuSIZE "\n",
|
|
mDeferred.size());
|
|
printf_stderr(" out-of-turn Interrupt replies stack size: %" PRIuSIZE "\n",
|
|
mOutOfTurnReplies.size());
|
|
printf_stderr(" Pending queue size: %" PRIuSIZE ", front to back:\n",
|
|
mPending.size());
|
|
|
|
MessageQueue pending = mPending;
|
|
while (!pending.empty()) {
|
|
printf_stderr(" [ %s%s ]\n",
|
|
pending.front().is_interrupt() ? "intr" :
|
|
(pending.front().is_sync() ? "sync" : "async"),
|
|
pending.front().is_reply() ? "reply" : "");
|
|
pending.pop_front();
|
|
}
|
|
|
|
NS_RUNTIMEABORT(why);
|
|
}
|
|
|
|
void
|
|
MessageChannel::DumpInterruptStack(const char* const pfx) const
|
|
{
|
|
NS_WARN_IF_FALSE(MessageLoop::current() != mWorkerLoop,
|
|
"The worker thread had better be paused in a debugger!");
|
|
|
|
printf_stderr("%sMessageChannel 'backtrace':\n", pfx);
|
|
|
|
// print a python-style backtrace, first frame to last
|
|
for (uint32_t i = 0; i < mCxxStackFrames.length(); ++i) {
|
|
int32_t id;
|
|
const char* dir;
|
|
const char* sems;
|
|
const char* name;
|
|
mCxxStackFrames[i].Describe(&id, &dir, &sems, &name);
|
|
|
|
printf_stderr("%s[(%u) %s %s %s(actor=%d) ]\n", pfx,
|
|
i, dir, sems, name, id);
|
|
}
|
|
}
|
|
|
|
int32_t
|
|
MessageChannel::GetTopmostMessageRoutingId() const
|
|
{
|
|
MOZ_ASSERT(MessageLoop::current() == mWorkerLoop);
|
|
if (mCxxStackFrames.empty()) {
|
|
return MSG_ROUTING_NONE;
|
|
}
|
|
const InterruptFrame& frame = mCxxStackFrames.back();
|
|
return frame.GetRoutingId();
|
|
}
|
|
|
|
void
|
|
MessageChannel::EndTimeout()
|
|
{
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
|
|
IPC_LOG("Ending timeout of seqno=%d", mTimedOutMessageSeqno);
|
|
mTimedOutMessageSeqno = 0;
|
|
mTimedOutMessagePriority = 0;
|
|
|
|
for (size_t i = 0; i < mPending.size(); i++) {
|
|
// There may be messages in the queue that we expected to process from
|
|
// OnMaybeDequeueOne. But during the timeout, that function will skip
|
|
// some messages. Now they're ready to be processed, so we enqueue more
|
|
// tasks.
|
|
mWorkerLoop->PostTask(FROM_HERE, new DequeueTask(mDequeueOneTask));
|
|
}
|
|
}
|
|
|
|
void
|
|
MessageChannel::CancelTransaction(int transaction)
|
|
{
|
|
mMonitor->AssertCurrentThreadOwns();
|
|
|
|
// When we cancel a transaction, we need to behave as if there's no longer
|
|
// any IPC on the stack. Anything we were dispatching or sending will get
|
|
// canceled. Consequently, we have to update the state variables below.
|
|
//
|
|
// We also need to ensure that when any IPC functions on the stack return,
|
|
// they don't reset these values using an RAII class like AutoSetValue. To
|
|
// avoid that, these RAII classes check if the variable they set has been
|
|
// tampered with (by us). If so, they don't reset the variable to the old
|
|
// value.
|
|
|
|
IPC_LOG("CancelTransaction: xid=%d prios=%d", transaction, mPendingSendPriorities);
|
|
|
|
if (mPendingSendPriorities & (1 << IPC::Message::PRIORITY_NORMAL)) {
|
|
// This isn't an assert so much as an intentional crash because we're in
|
|
// a situation that we don't know how to recover from: The child is
|
|
// awaiting a reply to a normal-priority sync message. The transaction
|
|
// that this message initiated has now been canceled. That could only
|
|
// happen if a CPOW raced with the sync message and was dispatched by
|
|
// the child while the child was awaiting the sync reply; at some point
|
|
// while dispatching the CPOW, the transaction was canceled.
|
|
//
|
|
// Notes:
|
|
//
|
|
// 1. We don't want to cancel the normal-priority sync message along
|
|
// with the CPOWs because the browser relies on these messages working
|
|
// reliably.
|
|
//
|
|
// 2. Ideally we would like to avoid dispatching CPOWs while awaiting a
|
|
// sync response. This isn't possible though. To avoid deadlock, the
|
|
// parent would have to dispatch the sync message while waiting for the
|
|
// CPOW response. However, it wouldn't have dispatched async messages at
|
|
// that time, so we would have a message ordering bug. Dispatching the
|
|
// async messages first causes other hard-to-handle situations (what if
|
|
// they send CPOWs?).
|
|
//
|
|
// 3. We would like to be able to cancel the CPOWs but not the sync
|
|
// message. However, that would leave both the parent and the child
|
|
// running code at the same time, all while the sync message is still
|
|
// outstanding. That can cause a problem where message replies are
|
|
// received out of order.
|
|
mListener->IntentionalCrash();
|
|
}
|
|
|
|
// An unusual case: We timed out a transaction which the other side then
|
|
// cancelled. In this case we just leave the timedout state and try to
|
|
// forget this ever happened.
|
|
if (transaction == mTimedOutMessageSeqno) {
|
|
IPC_LOG("Cancelled timed out message %d", mTimedOutMessageSeqno);
|
|
EndTimeout();
|
|
|
|
// Normally mCurrentTransaction == 0 here. But it can be non-zero if:
|
|
// 1. Parent sends hi prio message H.
|
|
// 2. Parent times out H.
|
|
// 3. Child dispatches H and sends nested message H' (same transaction).
|
|
// 4. Parent dispatches H' and cancels.
|
|
MOZ_ASSERT_IF(mCurrentTransaction, mCurrentTransaction == transaction);
|
|
mCurrentTransaction = 0;
|
|
|
|
// During a timeout Send should always fail.
|
|
MOZ_ASSERT(!mAwaitingSyncReply);
|
|
} else {
|
|
MOZ_ASSERT(mCurrentTransaction == transaction);
|
|
mCurrentTransaction = 0;
|
|
|
|
mAwaitingSyncReply = false;
|
|
mAwaitingSyncReplyPriority = 0;
|
|
}
|
|
|
|
DebugOnly<bool> foundSync = false;
|
|
for (MessageQueue::iterator it = mPending.begin(); it != mPending.end(); ) {
|
|
Message &msg = *it;
|
|
|
|
// If there was a race between the parent and the child, then we may
|
|
// have a queued sync message. We want to drop this message from the
|
|
// queue since it will get cancelled along with the transaction being
|
|
// cancelled. We don't bother doing this for normal priority messages
|
|
// because the child is just going to crash in that case, and we want to
|
|
// avoid processing messages out of order in the short time before it
|
|
// crashes.
|
|
if (msg.is_sync() && msg.priority() != IPC::Message::PRIORITY_NORMAL) {
|
|
MOZ_ASSERT(!foundSync);
|
|
MOZ_ASSERT(msg.transaction_id() != transaction);
|
|
IPC_LOG("Removing msg from queue seqno=%d xid=%d", msg.seqno(), msg.transaction_id());
|
|
foundSync = true;
|
|
it = mPending.erase(it);
|
|
continue;
|
|
}
|
|
|
|
// There may be messages in the queue that we expected to process from
|
|
// ProcessPendingRequests. However, Send will no longer call that
|
|
// function once it's been canceled. So we may need to process these
|
|
// messages in the normal event loop instead.
|
|
mWorkerLoop->PostTask(FROM_HERE, new DequeueTask(mDequeueOneTask));
|
|
|
|
it++;
|
|
}
|
|
|
|
// We could also zero out mDispatchingSyncMessage here. However, that would
|
|
// cause a race because mDispatchingSyncMessage is a worker-thread-only
|
|
// field and we can be called on the I/O thread. Luckily, we can check to
|
|
// see if mCurrentTransaction is 0 before examining DispatchSyncMessage.
|
|
}
|
|
|
|
void
|
|
MessageChannel::CancelCurrentTransaction()
|
|
{
|
|
MonitorAutoLock lock(*mMonitor);
|
|
if (mCurrentTransaction) {
|
|
if (DispatchingSyncMessagePriority() == IPC::Message::PRIORITY_URGENT ||
|
|
DispatchingAsyncMessagePriority() == IPC::Message::PRIORITY_URGENT)
|
|
{
|
|
mListener->IntentionalCrash();
|
|
}
|
|
|
|
IPC_LOG("Cancel requested: current xid=%d", mCurrentTransaction);
|
|
MOZ_ASSERT(DispatchingSyncMessage());
|
|
CancelMessage *cancel = new CancelMessage(mCurrentTransaction);
|
|
CancelTransaction(mCurrentTransaction);
|
|
mLink->SendMessage(cancel);
|
|
}
|
|
}
|
|
|
|
void
|
|
CancelCPOWs()
|
|
{
|
|
if (gParentProcessBlocker) {
|
|
mozilla::Telemetry::Accumulate(mozilla::Telemetry::IPC_TRANSACTION_CANCEL, true);
|
|
gParentProcessBlocker->CancelCurrentTransaction();
|
|
}
|
|
}
|
|
|
|
} // namespace ipc
|
|
} // namespace mozilla
|