예제 #1
0
static already_AddRefed<SharedMemory>
ReadSegment(const IPC::Message& aDescriptor, Shmem::id_t* aId, size_t* aNBytes, size_t aExtraSize)
{
  if (SHMEM_CREATED_MESSAGE_TYPE != aDescriptor.type()) {
    NS_ERROR("expected 'shmem created' message");
    return nullptr;
  }
  SharedMemory::SharedMemoryType type;
  PickleIterator iter(aDescriptor);
  if (!ShmemCreated::ReadInfo(&aDescriptor, &iter, aId, aNBytes, &type)) {
    return nullptr;
  }
  RefPtr<SharedMemory> segment = NewSegment(type);
  if (!segment) {
    return nullptr;
  }
  if (!segment->ReadHandle(&aDescriptor, &iter)) {
    NS_ERROR("trying to open invalid handle");
    return nullptr;
  }
  aDescriptor.EndRead(iter);
  size_t size = SharedMemory::PageAlignedSize(*aNBytes + aExtraSize);
  if (!segment->Map(size)) {
    return nullptr;
  }
  // close the handle to the segment after it is mapped
  segment->CloseHandle();
  return segment.forget();
}
예제 #2
0
// static
already_AddRefed<Shmem::SharedMemory>
Shmem::OpenExisting(IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead,
                    const IPC::Message& aDescriptor,
                    id_t* aId,
                    bool /*unused*/)
{
  if (SHMEM_CREATED_MESSAGE_TYPE != aDescriptor.type()) {
    return nullptr;
  }

  SharedMemory::SharedMemoryType type;
  void* iter = nullptr;
  size_t size;
  if (!ShmemCreated::ReadInfo(&aDescriptor, &iter, aId, &size, &type))
    return nullptr;

  nsRefPtr<SharedMemory> segment;
  size_t segmentSize = SharedMemory::PageAlignedSize(size + sizeof(uint32_t));

  if (SharedMemory::TYPE_BASIC == type) {
    SharedMemoryBasic::Handle handle;
    if (!ShmemCreated::ReadHandle(&aDescriptor, &iter, &handle))
      return nullptr;

    if (!SharedMemoryBasic::IsHandleValid(handle)) {
      return nullptr;
    }

    segment = CreateSegment(segmentSize, handle);
  }
#ifdef MOZ_HAVE_SHAREDMEMORYSYSV
  else if (SharedMemory::TYPE_SYSV == type) {
    SharedMemorySysV::Handle handle;
    if (!ShmemCreated::ReadHandle(&aDescriptor, &iter, &handle))
      return nullptr;

    if (!SharedMemorySysV::IsHandleValid(handle)) {
      return nullptr;
    }
    segment = CreateSegment(segmentSize, handle);
  }
#endif
  else {
    return nullptr;
  }

  if (!segment)
    return nullptr;

  // this is the only validity check done in non-DEBUG builds
  if (size != static_cast<size_t>(*PtrToSize(segment))) {
    return nullptr;
  }

  return segment.forget();
}
예제 #3
0
// static
already_AddRefed<Shmem::SharedMemory>
Shmem::OpenExisting(IHadBetterBeIPDLCodeCallingThis_OtherwiseIAmADoodyhead,
                    const IPC::Message& aDescriptor,
                    id_t* aId,
                    bool aProtect)
{
  if (SHMEM_CREATED_MESSAGE_TYPE != aDescriptor.type()) {
    NS_ERROR("expected 'shmem created' message");
    return nullptr;
  }

  void* iter = nullptr;
  SharedMemory::SharedMemoryType type;
  size_t size;
  if (!ShmemCreated::ReadInfo(&aDescriptor, &iter, aId, &size, &type))
    return nullptr;

  nsRefPtr<SharedMemory> segment;
  size_t pageSize = SharedMemory::SystemPageSize();
  // |2*pageSize| is for the front and back sentinels
  size_t segmentSize = SharedMemory::PageAlignedSize(size + 2*pageSize);

  if (SharedMemory::TYPE_BASIC == type) {
    SharedMemoryBasic::Handle handle;
    if (!ShmemCreated::ReadHandle(&aDescriptor, &iter, &handle))
      return nullptr;

    if (!SharedMemoryBasic::IsHandleValid(handle)) {
      NS_ERROR("trying to open invalid handle");
      return nullptr;
    }
    segment = CreateSegment(segmentSize, handle);
  }
#ifdef MOZ_HAVE_SHAREDMEMORYSYSV
  else if (SharedMemory::TYPE_SYSV == type) {
    SharedMemorySysV::Handle handle;
    if (!ShmemCreated::ReadHandle(&aDescriptor, &iter, &handle))
      return nullptr;

    if (!SharedMemorySysV::IsHandleValid(handle)) {
      NS_ERROR("trying to open invalid handle");
      return nullptr;
    }
    segment = CreateSegment(segmentSize, handle);
  }
#endif
  else {
    NS_ERROR("unknown shmem type");
    return nullptr;
  }

  if (!segment)
    return nullptr;

  Header* header = GetHeader(segment);

  if (size != header->mSize) {
    NS_ERROR("Wrong size for this Shmem!");
    return nullptr;
  }

  // The caller of this function may not know whether the segment is
  // unsafe or not
  if (!header->mUnsafe && aProtect)
    Protect(segment);

  return segment.forget();
}