gecko-dev/ipc/glue/IPCStreamUtils.cpp

/* -*- 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 "IPCStreamUtils.h"

#include "nsIIPCSerializableInputStream.h"

#include "mozilla/Assertions.h"
#include "mozilla/dom/ContentChild.h"
#include "mozilla/dom/ContentParent.h"
#include "mozilla/dom/File.h"
#include "mozilla/ipc/FileDescriptorSetChild.h"
#include "mozilla/ipc/FileDescriptorSetParent.h"
#include "mozilla/ipc/InputStreamUtils.h"
#include "mozilla/ipc/PBackgroundChild.h"
#include "mozilla/ipc/PBackgroundParent.h"
#include "mozilla/Unused.h"
#include "nsNetCID.h"

using namespace mozilla::dom;

namespace mozilla {
namespace ipc {

namespace {

// These serialization and cleanup functions could be externally exposed.  For
// now, though, keep them private to encourage use of the safer RAII
// AutoIPCStream class.

template <typename M>
bool SerializeInputStreamWithFdsChild(nsIIPCSerializableInputStream* aStream,
                                      IPCStream& aValue, bool aDelayedStart,
                                      M* aManager) {
  MOZ_RELEASE_ASSERT(aStream);
  MOZ_ASSERT(aManager);

  const uint64_t kTooLargeStream = 1024 * 1024;

  uint32_t sizeUsed = 0;
  AutoTArray<FileDescriptor, 4> fds;
  aStream->Serialize(aValue.stream(), fds, aDelayedStart, kTooLargeStream,
                     &sizeUsed, aManager);

  MOZ_ASSERT(sizeUsed <= kTooLargeStream);

  if (aValue.stream().type() == InputStreamParams::T__None) {
    MOZ_CRASH("Serialize failed!");
  }

  if (fds.IsEmpty()) {
    aValue.optionalFds() = void_t();
  } else {
    PFileDescriptorSetChild* fdSet =
        aManager->SendPFileDescriptorSetConstructor(fds[0]);
    for (uint32_t i = 1; i < fds.Length(); ++i) {
      Unused << fdSet->SendAddFileDescriptor(fds[i]);
    }

    aValue.optionalFds() = fdSet;
  }

  return true;
}

template <typename M>
bool SerializeInputStreamWithFdsParent(nsIIPCSerializableInputStream* aStream,
                                       IPCStream& aValue, bool aDelayedStart,
                                       M* aManager) {
  MOZ_RELEASE_ASSERT(aStream);
  MOZ_ASSERT(aManager);

  const uint64_t kTooLargeStream = 1024 * 1024;

  uint32_t sizeUsed = 0;
  AutoTArray<FileDescriptor, 4> fds;
  aStream->Serialize(aValue.stream(), fds, aDelayedStart, kTooLargeStream,
                     &sizeUsed, aManager);

  MOZ_ASSERT(sizeUsed <= kTooLargeStream);

  if (aValue.stream().type() == InputStreamParams::T__None) {
    MOZ_CRASH("Serialize failed!");
  }

  aValue.optionalFds() = void_t();
  if (!fds.IsEmpty()) {
    PFileDescriptorSetParent* fdSet =
        aManager->SendPFileDescriptorSetConstructor(fds[0]);
    for (uint32_t i = 1; i < fds.Length(); ++i) {
      if (NS_WARN_IF(!fdSet->SendAddFileDescriptor(fds[i]))) {
        Unused << PFileDescriptorSetParent::Send__delete__(fdSet);
        fdSet = nullptr;
        break;
      }
    }

    if (fdSet) {
      aValue.optionalFds() = fdSet;
    }
  }

  return true;
}

template <typename M>
bool SerializeInputStream(nsIInputStream* aStream, IPCStream& aValue,
                          M* aManager, bool aDelayedStart) {
  MOZ_ASSERT(aStream);
  MOZ_ASSERT(aManager);

  InputStreamParams params;
  InputStreamHelper::SerializeInputStreamAsPipe(aStream, params, aDelayedStart,
                                                aManager);

  if (params.type() == InputStreamParams::T__None) {
    return false;
  }

  aValue.stream() = params;
  aValue.optionalFds() = void_t();

  return true;
}

template <typename M>
bool SerializeInputStreamChild(nsIInputStream* aStream, M* aManager,
                               IPCStream* aValue,
                               Maybe<IPCStream>* aOptionalValue,
                               bool aDelayedStart) {
  MOZ_ASSERT(aStream);
  MOZ_ASSERT(aManager);
  MOZ_ASSERT(aValue || aOptionalValue);

  nsCOMPtr<nsIIPCSerializableInputStream> serializable =
      do_QueryInterface(aStream);

  if (serializable) {
    if (aValue) {
      return SerializeInputStreamWithFdsChild(serializable, *aValue,
                                              aDelayedStart, aManager);
    }

    return SerializeInputStreamWithFdsChild(serializable, aOptionalValue->ref(),
                                            aDelayedStart, aManager);
  }

  if (aValue) {
    return SerializeInputStream(aStream, *aValue, aManager, aDelayedStart);
  }

  return SerializeInputStream(aStream, aOptionalValue->ref(), aManager,
                              aDelayedStart);
}

template <typename M>
bool SerializeInputStreamParent(nsIInputStream* aStream, M* aManager,
                                IPCStream* aValue,
                                Maybe<IPCStream>* aOptionalValue,
                                bool aDelayedStart) {
  MOZ_ASSERT(aStream);
  MOZ_ASSERT(aManager);
  MOZ_ASSERT(aValue || aOptionalValue);

  nsCOMPtr<nsIIPCSerializableInputStream> serializable =
      do_QueryInterface(aStream);

  if (serializable) {
    if (aValue) {
      return SerializeInputStreamWithFdsParent(serializable, *aValue,
                                               aDelayedStart, aManager);
    }

    return SerializeInputStreamWithFdsParent(
        serializable, aOptionalValue->ref(), aDelayedStart, aManager);
  }

  if (aValue) {
    return SerializeInputStream(aStream, *aValue, aManager, aDelayedStart);
  }

  return SerializeInputStream(aStream, aOptionalValue->ref(), aManager,
                              aDelayedStart);
}

void ActivateAndCleanupIPCStream(IPCStream& aValue, bool aConsumedByIPC,
                                 bool aDelayedStart) {
  // Cleanup file descriptors if necessary
  if (aValue.optionalFds().type() ==
      OptionalFileDescriptorSet::TPFileDescriptorSetChild) {
    AutoTArray<FileDescriptor, 4> fds;

    auto fdSetActor = static_cast<FileDescriptorSetChild*>(
        aValue.optionalFds().get_PFileDescriptorSetChild());
    MOZ_ASSERT(fdSetActor);

    // FileDescriptorSet doesn't clear its fds in its ActorDestroy, so we
    // unconditionally forget them here.  The fds themselves are auto-closed
    // in ~FileDescriptor since they originated in this process.
    fdSetActor->ForgetFileDescriptors(fds);

    if (!aConsumedByIPC) {
      Unused << FileDescriptorSetChild::Send__delete__(fdSetActor);
    }

  } else if (aValue.optionalFds().type() ==
             OptionalFileDescriptorSet::TPFileDescriptorSetParent) {
    AutoTArray<FileDescriptor, 4> fds;

    auto fdSetActor = static_cast<FileDescriptorSetParent*>(
        aValue.optionalFds().get_PFileDescriptorSetParent());
    MOZ_ASSERT(fdSetActor);

    // FileDescriptorSet doesn't clear its fds in its ActorDestroy, so we
    // unconditionally forget them here.  The fds themselves are auto-closed
    // in ~FileDescriptor since they originated in this process.
    fdSetActor->ForgetFileDescriptors(fds);

    if (!aConsumedByIPC) {
      Unused << FileDescriptorSetParent::Send__delete__(fdSetActor);
    }
  }

  // Activate IPCRemoteStreamParams.
  InputStreamHelper::PostSerializationActivation(aValue.stream(),
                                                 aConsumedByIPC, aDelayedStart);
}

void ActivateAndCleanupIPCStream(Maybe<IPCStream>& aValue, bool aConsumedByIPC,
                                 bool aDelayedStart) {
  if (aValue.isNothing()) {
    return;
  }

  ActivateAndCleanupIPCStream(aValue.ref(), aConsumedByIPC, aDelayedStart);
}

// Returns false if the serialization should not proceed. This means that the
// inputStream is null.
bool NormalizeOptionalValue(nsIInputStream* aStream, IPCStream* aValue,
                            Maybe<IPCStream>* aOptionalValue) {
  if (aValue) {
    // if aStream is null, we will crash when serializing.
    return true;
  }

  if (!aStream) {
    aOptionalValue->reset();
    return false;
  }

  aOptionalValue->emplace();
  return true;
}

}  // anonymous namespace

already_AddRefed<nsIInputStream> DeserializeIPCStream(const IPCStream& aValue) {
  // Note, we explicitly do not support deserializing the PChildToParentStream
  // actor on the child side nor the PParentToChildStream actor on the parent
  // side.

  AutoTArray<FileDescriptor, 4> fds;
  if (aValue.optionalFds().type() ==
      OptionalFileDescriptorSet::TPFileDescriptorSetParent) {
    auto fdSetActor = static_cast<FileDescriptorSetParent*>(
        aValue.optionalFds().get_PFileDescriptorSetParent());
    MOZ_ASSERT(fdSetActor);

    fdSetActor->ForgetFileDescriptors(fds);
    MOZ_ASSERT(!fds.IsEmpty());

    if (!FileDescriptorSetParent::Send__delete__(fdSetActor)) {
      // child process is gone, warn and allow actor to clean up normally
      NS_WARNING("Failed to delete fd set actor.");
    }
  } else if (aValue.optionalFds().type() ==
             OptionalFileDescriptorSet::TPFileDescriptorSetChild) {
    auto fdSetActor = static_cast<FileDescriptorSetChild*>(
        aValue.optionalFds().get_PFileDescriptorSetChild());
    MOZ_ASSERT(fdSetActor);

    fdSetActor->ForgetFileDescriptors(fds);
    MOZ_ASSERT(!fds.IsEmpty());

    Unused << FileDescriptorSetChild::Send__delete__(fdSetActor);
  }

  return InputStreamHelper::DeserializeInputStream(aValue.stream(), fds);
}

already_AddRefed<nsIInputStream> DeserializeIPCStream(
    const Maybe<IPCStream>& aValue) {
  if (aValue.isNothing()) {
    return nullptr;
  }

  return DeserializeIPCStream(aValue.ref());
}

AutoIPCStream::AutoIPCStream(bool aDelayedStart)
    : mOptionalValue(&mInlineValue), mDelayedStart(aDelayedStart) {}

AutoIPCStream::AutoIPCStream(IPCStream& aTarget, bool aDelayedStart)
    : mValue(&aTarget), mDelayedStart(aDelayedStart) {}

AutoIPCStream::AutoIPCStream(Maybe<IPCStream>& aTarget, bool aDelayedStart)
    : mOptionalValue(&aTarget), mDelayedStart(aDelayedStart) {
  mOptionalValue->reset();
}

AutoIPCStream::~AutoIPCStream() {
  MOZ_ASSERT(mValue || mOptionalValue);
  if (mValue && IsSet()) {
    ActivateAndCleanupIPCStream(*mValue, mTaken, mDelayedStart);
  } else {
    ActivateAndCleanupIPCStream(*mOptionalValue, mTaken, mDelayedStart);
  }
}

bool AutoIPCStream::Serialize(nsIInputStream* aStream,
                              dom::ContentChild* aManager) {
  MOZ_ASSERT(aStream || !mValue);
  MOZ_ASSERT(aManager);
  MOZ_ASSERT(mValue || mOptionalValue);
  MOZ_ASSERT(!mTaken);
  MOZ_ASSERT(!IsSet());

  // If NormalizeOptionalValue returns false, we don't have to proceed.
  if (!NormalizeOptionalValue(aStream, mValue, mOptionalValue)) {
    return true;
  }

  if (!SerializeInputStreamChild(aStream, aManager, mValue, mOptionalValue,
                                 mDelayedStart)) {
    MOZ_CRASH("IPCStream creation failed!");
  }

  return true;
}

bool AutoIPCStream::Serialize(nsIInputStream* aStream,
                              PBackgroundChild* aManager) {
  MOZ_ASSERT(aStream || !mValue);
  MOZ_ASSERT(aManager);
  MOZ_ASSERT(mValue || mOptionalValue);
  MOZ_ASSERT(!mTaken);
  MOZ_ASSERT(!IsSet());

  // If NormalizeOptionalValue returns false, we don't have to proceed.
  if (!NormalizeOptionalValue(aStream, mValue, mOptionalValue)) {
    return true;
  }

  if (!SerializeInputStreamChild(aStream, aManager, mValue, mOptionalValue,
                                 mDelayedStart)) {
    MOZ_CRASH("IPCStream creation failed!");
  }

  return true;
}

bool AutoIPCStream::Serialize(nsIInputStream* aStream,
                              dom::ContentParent* aManager) {
  MOZ_ASSERT(aStream || !mValue);
  MOZ_ASSERT(aManager);
  MOZ_ASSERT(mValue || mOptionalValue);
  MOZ_ASSERT(!mTaken);
  MOZ_ASSERT(!IsSet());

  // If NormalizeOptionalValue returns false, we don't have to proceed.
  if (!NormalizeOptionalValue(aStream, mValue, mOptionalValue)) {
    return true;
  }

  if (!SerializeInputStreamParent(aStream, aManager, mValue, mOptionalValue,
                                  mDelayedStart)) {
    return false;
  }

  return true;
}

bool AutoIPCStream::Serialize(nsIInputStream* aStream,
                              PBackgroundParent* aManager) {
  MOZ_ASSERT(aStream || !mValue);
  MOZ_ASSERT(aManager);
  MOZ_ASSERT(mValue || mOptionalValue);
  MOZ_ASSERT(!mTaken);
  MOZ_ASSERT(!IsSet());

  // If NormalizeOptionalValue returns false, we don't have to proceed.
  if (!NormalizeOptionalValue(aStream, mValue, mOptionalValue)) {
    return true;
  }

  if (!SerializeInputStreamParent(aStream, aManager, mValue, mOptionalValue,
                                  mDelayedStart)) {
    return false;
  }

  return true;
}

bool AutoIPCStream::IsSet() const {
  MOZ_ASSERT(mValue || mOptionalValue);
  if (mValue) {
    return mValue->stream().type() != InputStreamParams::T__None;
  } else {
    return mOptionalValue->isSome() &&
           mOptionalValue->ref().stream().type() != InputStreamParams::T__None;
  }
}

IPCStream& AutoIPCStream::TakeValue() {
  MOZ_ASSERT(mValue || mOptionalValue);
  MOZ_ASSERT(!mTaken);
  MOZ_ASSERT(IsSet());

  mTaken = true;

  if (mValue) {
    return *mValue;
  }

  IPCStream& value = mOptionalValue->ref();
  return value;
}

Maybe<IPCStream>& AutoIPCStream::TakeOptionalValue() {
  MOZ_ASSERT(!mTaken);
  MOZ_ASSERT(!mValue);
  MOZ_ASSERT(mOptionalValue);
  mTaken = true;
  return *mOptionalValue;
}

void IPDLParamTraits<nsIInputStream*>::Write(IPC::Message* aMsg,
                                             IProtocol* aActor,
                                             nsIInputStream* aParam) {
  mozilla::ipc::AutoIPCStream autoStream;
  bool ok = false;
  bool found = false;

  // We can only serialize our nsIInputStream if it's going to be sent over one
  // of the protocols we support, or a protocol which is managed by one of the
  // protocols we support.
  IProtocol* actor = aActor;
  while (!found && actor) {
    switch (actor->GetProtocolId()) {
      case PContentMsgStart:
        if (actor->GetSide() == mozilla::ipc::ParentSide) {
          ok = autoStream.Serialize(
              aParam, static_cast<mozilla::dom::ContentParent*>(actor));
        } else {
          MOZ_RELEASE_ASSERT(actor->GetSide() == mozilla::ipc::ChildSide);
          ok = autoStream.Serialize(
              aParam, static_cast<mozilla::dom::ContentChild*>(actor));
        }
        found = true;
        break;
      case PBackgroundMsgStart:
        if (actor->GetSide() == mozilla::ipc::ParentSide) {
          ok = autoStream.Serialize(
              aParam, static_cast<mozilla::ipc::PBackgroundParent*>(actor));
        } else {
          MOZ_RELEASE_ASSERT(actor->GetSide() == mozilla::ipc::ChildSide);
          ok = autoStream.Serialize(
              aParam, static_cast<mozilla::ipc::PBackgroundChild*>(actor));
        }
        found = true;
        break;
      default:
        break;
    }

    // Try the actor's manager.
    actor = actor->Manager();
  }

  if (!found) {
    aActor->FatalError(
        "Attempt to send nsIInputStream over an unsupported ipdl protocol");
  }
  MOZ_RELEASE_ASSERT(ok, "Failed to serialize nsIInputStream");

  WriteIPDLParam(aMsg, aActor, autoStream.TakeOptionalValue());
}

bool IPDLParamTraits<nsIInputStream*>::Read(const IPC::Message* aMsg,
                                            PickleIterator* aIter,
                                            IProtocol* aActor,
                                            RefPtr<nsIInputStream>* aResult) {
  mozilla::Maybe<mozilla::ipc::IPCStream> ipcStream;
  if (!ReadIPDLParam(aMsg, aIter, aActor, &ipcStream)) {
    return false;
  }

  *aResult = mozilla::ipc::DeserializeIPCStream(ipcStream);
  return true;
}

}  // namespace ipc
}  // namespace mozilla