import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

ipc/glue/ProtocolUtils.cpp

@@ -0,0 +1,720 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "base/process_util.h"
+#include "base/task.h"
+
+#ifdef OS_POSIX
+#include <errno.h>
+#endif
+
+#include "mozilla/ipc/ProtocolUtils.h"
+
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/ipc/MessageChannel.h"
+#include "mozilla/ipc/Transport.h"
+#include "mozilla/StaticMutex.h"
+#include "mozilla/Unused.h"
+#include "nsPrintfCString.h"
+
+#if defined(MOZ_SANDBOX) && defined(XP_WIN)
+#define TARGET_SANDBOX_EXPORTS
+#include "mozilla/sandboxTarget.h"
+#endif
+
+#if defined(MOZ_CRASHREPORTER) && defined(XP_WIN)
+#include "aclapi.h"
+#include "sddl.h"
+
+#include "mozilla/TypeTraits.h"
+#endif
+
+#include "nsAutoPtr.h"
+
+using namespace IPC;
+
+using base::GetCurrentProcId;
+using base::ProcessHandle;
+using base::ProcessId;
+
+namespace mozilla {
+
+#if defined(MOZ_CRASHREPORTER) && defined(XP_WIN)
+// Generate RAII classes for LPTSTR and PSECURITY_DESCRIPTOR.
+MOZ_TYPE_SPECIFIC_SCOPED_POINTER_TEMPLATE(ScopedLPTStr, \
+                                          RemovePointer<LPTSTR>::Type, \
+                                          ::LocalFree)
+MOZ_TYPE_SPECIFIC_SCOPED_POINTER_TEMPLATE(ScopedPSecurityDescriptor, \
+                                          RemovePointer<PSECURITY_DESCRIPTOR>::Type, \
+                                          ::LocalFree)
+#endif
+
+namespace ipc {
+
+class ChannelOpened : public IPC::Message
+{
+public:
+  ChannelOpened(TransportDescriptor aDescriptor,
+                ProcessId aOtherProcess,
+                ProtocolId aProtocol,
+                NestedLevel aNestedLevel = NOT_NESTED)
+    : IPC::Message(MSG_ROUTING_CONTROL, // these only go to top-level actors
+                   CHANNEL_OPENED_MESSAGE_TYPE,
+                   aNestedLevel)
+  {
+    IPC::WriteParam(this, aDescriptor);
+    IPC::WriteParam(this, aOtherProcess);
+    IPC::WriteParam(this, static_cast<uint32_t>(aProtocol));
+  }
+
+  static bool Read(const IPC::Message& aMsg,
+                   TransportDescriptor* aDescriptor,
+                   ProcessId* aOtherProcess,
+                   ProtocolId* aProtocol)
+  {
+    PickleIterator iter(aMsg);
+    if (!IPC::ReadParam(&aMsg, &iter, aDescriptor) ||
+        !IPC::ReadParam(&aMsg, &iter, aOtherProcess) ||
+        !IPC::ReadParam(&aMsg, &iter, reinterpret_cast<uint32_t*>(aProtocol))) {
+      return false;
+    }
+    aMsg.EndRead(iter);
+    return true;
+  }
+};
+
+nsresult
+Bridge(const PrivateIPDLInterface&,
+       MessageChannel* aParentChannel, ProcessId aParentPid,
+       MessageChannel* aChildChannel, ProcessId aChildPid,
+       ProtocolId aProtocol, ProtocolId aChildProtocol)
+{
+  if (!aParentPid || !aChildPid) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  TransportDescriptor parentSide, childSide;
+  nsresult rv;
+  if (NS_FAILED(rv = CreateTransport(aParentPid, &parentSide, &childSide))) {
+    return rv;
+  }
+
+  if (!aParentChannel->Send(new ChannelOpened(parentSide,
+                                              aChildPid,
+                                              aProtocol,
+                                              IPC::Message::NESTED_INSIDE_CPOW))) {
+    CloseDescriptor(parentSide);
+    CloseDescriptor(childSide);
+    return NS_ERROR_BRIDGE_OPEN_PARENT;
+  }
+
+  if (!aChildChannel->Send(new ChannelOpened(childSide,
+                                            aParentPid,
+                                            aChildProtocol,
+                                            IPC::Message::NESTED_INSIDE_CPOW))) {
+    CloseDescriptor(parentSide);
+    CloseDescriptor(childSide);
+    return NS_ERROR_BRIDGE_OPEN_CHILD;
+  }
+
+  return NS_OK;
+}
+
+bool
+Open(const PrivateIPDLInterface&,
+     MessageChannel* aOpenerChannel, ProcessId aOtherProcessId,
+     Transport::Mode aOpenerMode,
+     ProtocolId aProtocol, ProtocolId aChildProtocol)
+{
+  bool isParent = (Transport::MODE_SERVER == aOpenerMode);
+  ProcessId thisPid = GetCurrentProcId();
+  ProcessId parentId = isParent ? thisPid : aOtherProcessId;
+  ProcessId childId = !isParent ? thisPid : aOtherProcessId;
+  if (!parentId || !childId) {
+    return false;
+  }
+
+  TransportDescriptor parentSide, childSide;
+  if (NS_FAILED(CreateTransport(parentId, &parentSide, &childSide))) {
+    return false;
+  }
+
+  Message* parentMsg = new ChannelOpened(parentSide, childId, aProtocol);
+  Message* childMsg = new ChannelOpened(childSide, parentId, aChildProtocol);
+  nsAutoPtr<Message> messageForUs(isParent ? parentMsg : childMsg);
+  nsAutoPtr<Message> messageForOtherSide(!isParent ? parentMsg : childMsg);
+  if (!aOpenerChannel->Echo(messageForUs.forget()) ||
+      !aOpenerChannel->Send(messageForOtherSide.forget())) {
+    CloseDescriptor(parentSide);
+    CloseDescriptor(childSide);
+    return false;
+  }
+  return true;
+}
+
+bool
+UnpackChannelOpened(const PrivateIPDLInterface&,
+                    const Message& aMsg,
+                    TransportDescriptor* aTransport,
+                    ProcessId* aOtherProcess,
+                    ProtocolId* aProtocol)
+{
+  return ChannelOpened::Read(aMsg, aTransport, aOtherProcess, aProtocol);
+}
+
+#if defined(XP_WIN)
+bool DuplicateHandle(HANDLE aSourceHandle,
+                     DWORD aTargetProcessId,
+                     HANDLE* aTargetHandle,
+                     DWORD aDesiredAccess,
+                     DWORD aOptions) {
+  // If our process is the target just duplicate the handle.
+  if (aTargetProcessId == base::GetCurrentProcId()) {
+    return !!::DuplicateHandle(::GetCurrentProcess(), aSourceHandle,
+                               ::GetCurrentProcess(), aTargetHandle,
+                               aDesiredAccess, false, aOptions);
+
+  }
+
+#if defined(MOZ_SANDBOX)
+  // Try the broker next (will fail if not sandboxed).
+  if (SandboxTarget::Instance()->BrokerDuplicateHandle(aSourceHandle,
+                                                       aTargetProcessId,
+                                                       aTargetHandle,
+                                                       aDesiredAccess,
+                                                       aOptions)) {
+    return true;
+  }
+#endif
+
+  // Finally, see if we already have access to the process.
+  ScopedProcessHandle targetProcess(OpenProcess(PROCESS_DUP_HANDLE,
+                                                FALSE,
+                                                aTargetProcessId));
+  if (!targetProcess) {
+#ifdef MOZ_CRASHREPORTER
+    CrashReporter::AnnotateCrashReport(
+      NS_LITERAL_CSTRING("IPCTransportFailureReason"),
+      NS_LITERAL_CSTRING("Failed to open target process."));
+#endif
+    return false;
+  }
+
+  return !!::DuplicateHandle(::GetCurrentProcess(), aSourceHandle,
+                              targetProcess, aTargetHandle,
+                              aDesiredAccess, FALSE, aOptions);
+}
+#endif
+
+#ifdef MOZ_CRASHREPORTER
+void
+AnnotateSystemError()
+{
+  int64_t error = 0;
+#if defined(XP_WIN)
+  error = ::GetLastError();
+#elif defined(OS_POSIX)
+  error = errno;
+#endif
+  if (error) {
+    CrashReporter::AnnotateCrashReport(
+      NS_LITERAL_CSTRING("IPCSystemError"),
+      nsPrintfCString("%lld", error));
+  }
+}
+#endif
+
+#if defined(MOZ_CRASHREPORTER) && defined(XP_MACOSX)
+void
+AnnotateCrashReportWithErrno(const char* tag, int error)
+{
+  CrashReporter::AnnotateCrashReport(
+    nsCString(tag),
+    nsPrintfCString("%d", error));
+}
+#endif
+
+void
+LogMessageForProtocol(const char* aTopLevelProtocol, base::ProcessId aOtherPid,
+                      const char* aContextDescription,
+                      uint32_t aMessageId,
+                      MessageDirection aDirection)
+{
+  nsPrintfCString logMessage("[time: %" PRId64 "][%d%s%d] [%s] %s %s\n",
+                             PR_Now(), base::GetCurrentProcId(),
+                             aDirection == MessageDirection::eReceiving ? "<-" : "->",
+                             aOtherPid, aTopLevelProtocol,
+                             aContextDescription,
+                             StringFromIPCMessageType(aMessageId));
+#ifdef ANDROID
+  __android_log_write(ANDROID_LOG_INFO, "GeckoIPC", logMessage.get());
+#endif
+  fputs(logMessage.get(), stderr);
+}
+
+void
+ProtocolErrorBreakpoint(const char* aMsg)
+{
+    // Bugs that generate these error messages can be tough to
+    // reproduce.  Log always in the hope that someone finds the error
+    // message.
+    printf_stderr("IPDL protocol error: %s\n", aMsg);
+}
+
+void
+FatalError(const char* aProtocolName, const char* aMsg, bool aIsParent)
+{
+  ProtocolErrorBreakpoint(aMsg);
+
+  nsAutoCString formattedMessage("IPDL error [");
+  formattedMessage.AppendASCII(aProtocolName);
+  formattedMessage.AppendLiteral("]: \"");
+  formattedMessage.AppendASCII(aMsg);
+  if (aIsParent) {
+#ifdef MOZ_CRASHREPORTER
+    // We're going to crash the parent process because at this time
+    // there's no other really nice way of getting a minidump out of
+    // this process if we're off the main thread.
+    formattedMessage.AppendLiteral("\". Intentionally crashing.");
+    NS_ERROR(formattedMessage.get());
+    CrashReporter::AnnotateCrashReport(NS_LITERAL_CSTRING("IPCFatalErrorProtocol"),
+                                       nsDependentCString(aProtocolName));
+    CrashReporter::AnnotateCrashReport(NS_LITERAL_CSTRING("IPCFatalErrorMsg"),
+                                       nsDependentCString(aMsg));
+    AnnotateSystemError();
+#endif
+    MOZ_CRASH("IPC FatalError in the parent process!");
+  } else {
+    formattedMessage.AppendLiteral("\". abort()ing as a result.");
+    NS_RUNTIMEABORT(formattedMessage.get());
+  }
+}
+
+void
+LogicError(const char* aMsg)
+{
+  NS_RUNTIMEABORT(aMsg);
+}
+
+void
+ActorIdReadError(const char* aActorDescription)
+{
+  nsPrintfCString message("Error deserializing id for %s", aActorDescription);
+  NS_RUNTIMEABORT(message.get());
+}
+
+void
+BadActorIdError(const char* aActorDescription)
+{
+  nsPrintfCString message("bad id for %s", aActorDescription);
+  ProtocolErrorBreakpoint(message.get());
+}
+
+void
+ActorLookupError(const char* aActorDescription)
+{
+  nsPrintfCString message("could not lookup id for %s", aActorDescription);
+  ProtocolErrorBreakpoint(message.get());
+}
+
+void
+MismatchedActorTypeError(const char* aActorDescription)
+{
+  nsPrintfCString message("actor that should be of type %s has different type",
+                          aActorDescription);
+  ProtocolErrorBreakpoint(message.get());
+}
+
+void
+UnionTypeReadError(const char* aUnionName)
+{
+  nsPrintfCString message("error deserializing type of union %s", aUnionName);
+  NS_RUNTIMEABORT(message.get());
+}
+
+void ArrayLengthReadError(const char* aElementName)
+{
+  nsPrintfCString message("error deserializing length of %s[]", aElementName);
+  NS_RUNTIMEABORT(message.get());
+}
+
+void
+TableToArray(const nsTHashtable<nsPtrHashKey<void>>& aTable,
+             nsTArray<void*>& aArray)
+{
+  uint32_t i = 0;
+  void** elements = aArray.AppendElements(aTable.Count());
+  for (auto iter = aTable.ConstIter(); !iter.Done(); iter.Next()) {
+    elements[i] = iter.Get()->GetKey();
+    ++i;
+  }
+}
+
+Maybe<IProtocol*>
+IProtocol::ReadActor(const IPC::Message* aMessage, PickleIterator* aIter, bool aNullable,
+                     const char* aActorDescription, int32_t aProtocolTypeId)
+{
+    int32_t id;
+    if (!IPC::ReadParam(aMessage, aIter, &id)) {
+        ActorIdReadError(aActorDescription);
+        return Nothing();
+    }
+
+    if (id == 1 || (id == 0 && !aNullable)) {
+        BadActorIdError(aActorDescription);
+        return Nothing();
+    }
+
+    if (id == 0) {
+        return Some(static_cast<IProtocol*>(nullptr));
+    }
+
+    IProtocol* listener = this->Lookup(id);
+    if (!listener) {
+        ActorLookupError(aActorDescription);
+        return Nothing();
+    }
+
+    if (listener->GetProtocolTypeId() != aProtocolTypeId) {
+        MismatchedActorTypeError(aActorDescription);
+        return Nothing();
+    }
+
+    return Some(listener);
+}
+
+int32_t
+IProtocol::Register(IProtocol* aRouted)
+{
+  return Manager()->Register(aRouted);
+}
+
+int32_t
+IProtocol::RegisterID(IProtocol* aRouted, int32_t aId)
+{
+  return Manager()->RegisterID(aRouted, aId);
+}
+
+IProtocol*
+IProtocol::Lookup(int32_t aId)
+{
+  return Manager()->Lookup(aId);
+}
+
+void
+IProtocol::Unregister(int32_t aId)
+{
+  Manager()->Unregister(aId);
+}
+
+Shmem::SharedMemory*
+IProtocol::CreateSharedMemory(size_t aSize,
+                              SharedMemory::SharedMemoryType aType,
+                              bool aUnsafe,
+                              int32_t* aId)
+{
+  return Manager()->CreateSharedMemory(aSize, aType, aUnsafe, aId);
+}
+
+Shmem::SharedMemory*
+IProtocol::LookupSharedMemory(int32_t aId)
+{
+  return Manager()->LookupSharedMemory(aId);
+}
+
+bool
+IProtocol::IsTrackingSharedMemory(Shmem::SharedMemory* aSegment)
+{
+  return Manager()->IsTrackingSharedMemory(aSegment);
+}
+
+bool
+IProtocol::DestroySharedMemory(Shmem& aShmem)
+{
+  return Manager()->DestroySharedMemory(aShmem);
+}
+
+ProcessId
+IProtocol::OtherPid() const
+{
+  return Manager()->OtherPid();
+}
+
+void
+IProtocol::FatalError(const char* const aErrorMsg) const
+{
+  HandleFatalError(ProtocolName(), aErrorMsg);
+}
+
+void
+IProtocol::HandleFatalError(const char* aProtocolName, const char* aErrorMsg) const
+{
+  if (IProtocol* manager = Manager()) {
+    manager->HandleFatalError(aProtocolName, aErrorMsg);
+    return;
+  }
+
+  mozilla::ipc::FatalError(aProtocolName, aErrorMsg, mSide == ParentSide);
+}
+
+bool
+IProtocol::AllocShmem(size_t aSize,
+                      Shmem::SharedMemory::SharedMemoryType aType,
+                      Shmem* aOutMem)
+{
+  Shmem::id_t id;
+  Shmem::SharedMemory* rawmem(CreateSharedMemory(aSize, aType, false, &id));
+  if (!rawmem) {
+    return false;
+  }
+
+  *aOutMem = Shmem(Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead(), rawmem, id);
+  return true;
+}
+
+bool
+IProtocol::AllocUnsafeShmem(size_t aSize,
+                            Shmem::SharedMemory::SharedMemoryType aType,
+                            Shmem* aOutMem)
+{
+  Shmem::id_t id;
+  Shmem::SharedMemory* rawmem(CreateSharedMemory(aSize, aType, true, &id));
+  if (!rawmem) {
+    return false;
+  }
+
+  *aOutMem = Shmem(Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead(), rawmem, id);
+  return true;
+}
+
+bool
+IProtocol::DeallocShmem(Shmem& aMem)
+{
+  bool ok = DestroySharedMemory(aMem);
+#ifdef DEBUG
+  if (!ok) {
+    if (mSide == ChildSide) {
+      FatalError("bad Shmem");
+    } else {
+      NS_WARNING("bad Shmem");
+    }
+    return false;
+  }
+#endif // DEBUG
+  aMem.forget(Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead());
+  return ok;
+}
+
+IToplevelProtocol::IToplevelProtocol(ProtocolId aProtoId, Side aSide)
+ : IProtocol(aSide),
+   mProtocolId(aProtoId),
+   mOtherPid(mozilla::ipc::kInvalidProcessId),
+   mLastRouteId(aSide == ParentSide ? 1 : 0),
+   mLastShmemId(aSide == ParentSide ? 1 : 0)
+{
+}
+
+IToplevelProtocol::~IToplevelProtocol()
+{
+  if (mTrans) {
+    RefPtr<DeleteTask<Transport>> task = new DeleteTask<Transport>(mTrans.release());
+    XRE_GetIOMessageLoop()->PostTask(task.forget());
+  }
+}
+
+base::ProcessId
+IToplevelProtocol::OtherPid() const
+{
+  return mOtherPid;
+}
+
+void
+IToplevelProtocol::SetOtherProcessId(base::ProcessId aOtherPid)
+{
+  mOtherPid = aOtherPid;
+}
+
+bool
+IToplevelProtocol::TakeMinidump(nsIFile** aDump, uint32_t* aSequence)
+{
+  MOZ_RELEASE_ASSERT(GetSide() == ParentSide);
+#ifdef MOZ_CRASHREPORTER
+  return XRE_TakeMinidumpForChild(OtherPid(), aDump, aSequence);
+#else
+  return false;
+#endif
+}
+
+bool
+IToplevelProtocol::Open(mozilla::ipc::Transport* aTransport,
+                        base::ProcessId aOtherPid,
+                        MessageLoop* aThread,
+                        mozilla::ipc::Side aSide)
+{
+  SetOtherProcessId(aOtherPid);
+  return GetIPCChannel()->Open(aTransport, aThread, aSide);
+}
+
+bool
+IToplevelProtocol::Open(MessageChannel* aChannel,
+                        MessageLoop* aMessageLoop,
+                        mozilla::ipc::Side aSide)
+{
+  SetOtherProcessId(base::GetCurrentProcId());
+  return GetIPCChannel()->Open(aChannel, aMessageLoop, aSide);
+}
+
+void
+IToplevelProtocol::Close()
+{
+  GetIPCChannel()->Close();
+}
+
+void
+IToplevelProtocol::SetReplyTimeoutMs(int32_t aTimeoutMs)
+{
+  GetIPCChannel()->SetReplyTimeoutMs(aTimeoutMs);
+}
+
+bool
+IToplevelProtocol::IsOnCxxStack() const
+{
+  return GetIPCChannel()->IsOnCxxStack();
+}
+
+int32_t
+IToplevelProtocol::Register(IProtocol* aRouted)
+{
+  int32_t id = GetSide() == ParentSide ? ++mLastRouteId : --mLastRouteId;
+  mActorMap.AddWithID(aRouted, id);
+  return id;
+}
+
+int32_t
+IToplevelProtocol::RegisterID(IProtocol* aRouted,
+                              int32_t aId)
+{
+  mActorMap.AddWithID(aRouted, aId);
+  return aId;
+}
+
+IProtocol*
+IToplevelProtocol::Lookup(int32_t aId)
+{
+  return mActorMap.Lookup(aId);
+}
+
+void
+IToplevelProtocol::Unregister(int32_t aId)
+{
+  return mActorMap.Remove(aId);
+}
+
+Shmem::SharedMemory*
+IToplevelProtocol::CreateSharedMemory(size_t aSize,
+                                      Shmem::SharedMemory::SharedMemoryType aType,
+                                      bool aUnsafe,
+                                      Shmem::id_t* aId)
+{
+  RefPtr<Shmem::SharedMemory> segment(
+    Shmem::Alloc(Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead(), aSize, aType, aUnsafe));
+  if (!segment) {
+    return nullptr;
+  }
+  int32_t id = GetSide() == ParentSide ? ++mLastShmemId : --mLastShmemId;
+  Shmem shmem(
+    Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead(),
+    segment.get(),
+    id);
+  Message* descriptor = shmem.ShareTo(
+    Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead(), OtherPid(), MSG_ROUTING_CONTROL);
+  if (!descriptor) {
+    return nullptr;
+  }
+  Unused << GetIPCChannel()->Send(descriptor);
+
+  *aId = shmem.Id(Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead());
+  Shmem::SharedMemory* rawSegment = segment.get();
+  mShmemMap.AddWithID(segment.forget().take(), *aId);
+  return rawSegment;
+}
+
+Shmem::SharedMemory*
+IToplevelProtocol::LookupSharedMemory(Shmem::id_t aId)
+{
+  return mShmemMap.Lookup(aId);
+}
+
+bool
+IToplevelProtocol::IsTrackingSharedMemory(Shmem::SharedMemory* segment)
+{
+  return mShmemMap.HasData(segment);
+}
+
+bool
+IToplevelProtocol::DestroySharedMemory(Shmem& shmem)
+{
+  Shmem::id_t aId = shmem.Id(Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead());
+  Shmem::SharedMemory* segment = LookupSharedMemory(aId);
+  if (!segment) {
+    return false;
+  }
+
+  Message* descriptor = shmem.UnshareFrom(
+    Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead(), OtherPid(), MSG_ROUTING_CONTROL);
+
+  mShmemMap.Remove(aId);
+  Shmem::Dealloc(Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead(), segment);
+
+  if (!GetIPCChannel()->CanSend()) {
+    delete descriptor;
+    return true;
+  }
+
+  return descriptor && GetIPCChannel()->Send(descriptor);
+}
+
+void
+IToplevelProtocol::DeallocShmems()
+{
+  for (IDMap<SharedMemory>::const_iterator cit = mShmemMap.begin(); cit != mShmemMap.end(); ++cit) {
+    Shmem::Dealloc(Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead(), cit->second);
+  }
+  mShmemMap.Clear();
+}
+
+bool
+IToplevelProtocol::ShmemCreated(const Message& aMsg)
+{
+  Shmem::id_t id;
+  RefPtr<Shmem::SharedMemory> rawmem(Shmem::OpenExisting(Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead(), aMsg, &id, true));
+  if (!rawmem) {
+    return false;
+  }
+  mShmemMap.AddWithID(rawmem.forget().take(), id);
+  return true;
+}
+
+bool
+IToplevelProtocol::ShmemDestroyed(const Message& aMsg)
+{
+  Shmem::id_t id;
+  PickleIterator iter = PickleIterator(aMsg);
+  if (!IPC::ReadParam(&aMsg, &iter, &id)) {
+    return false;
+  }
+  aMsg.EndRead(iter);
+
+  Shmem::SharedMemory* rawmem = LookupSharedMemory(id);
+  if (rawmem) {
+    mShmemMap.Remove(id);
+    Shmem::Dealloc(Shmem::IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead(), rawmem);
+  }
+  return true;
+}
+
+} // namespace ipc
+} // namespace mozilla