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// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "mojo/edk/system/broker_host.h"
#include <utility>
#include "base/logging.h"
#include "base/memory/ref_counted.h"
#include "base/message_loop/message_loop.h"
#include "base/threading/thread_task_runner_handle.h"
#include "mojo/edk/embedder/named_platform_channel_pair.h"
#include "mojo/edk/embedder/named_platform_handle.h"
#include "mojo/edk/embedder/platform_handle_vector.h"
#include "mojo/edk/embedder/platform_shared_buffer.h"
#include "mojo/edk/system/broker_messages.h"
namespace mojo {
namespace edk {
BrokerHost::BrokerHost(base::ProcessHandle client_process,
ScopedPlatformHandle platform_handle)
#if defined(OS_WIN)
: client_process_(client_process)
#endif
{
CHECK(platform_handle.is_valid());
base::MessageLoop::current()->AddDestructionObserver(this);
channel_ = Channel::Create(
this, std::move(platform_handle), base::ThreadTaskRunnerHandle::Get());
channel_->Start();
}
BrokerHost::~BrokerHost() {
// We're always destroyed on the creation thread, which is the IO thread.
base::MessageLoop::current()->RemoveDestructionObserver(this);
if (channel_)
channel_->ShutDown();
}
bool BrokerHost::PrepareHandlesForClient(PlatformHandleVector* handles) {
#if defined(OS_WIN)
if (!Channel::Message::RewriteHandles(
base::GetCurrentProcessHandle(), client_process_, handles)) {
// NOTE: We only log an error here. We do not signal a logical error or
// prevent any message from being sent. The client should handle unexpected
// invalid handles appropriately.
DLOG(ERROR) << "Failed to rewrite one or more handles to broker client.";
return false;
}
#endif
return true;
}
bool BrokerHost::SendChannel(ScopedPlatformHandle handle) {
CHECK(handle.is_valid());
CHECK(channel_);
#if defined(OS_WIN)
InitData* data;
Channel::MessagePtr message =
CreateBrokerMessage(BrokerMessageType::INIT, 1, 0, &data);
data->pipe_name_length = 0;
#else
Channel::MessagePtr message =
CreateBrokerMessage(BrokerMessageType::INIT, 1, nullptr);
#endif
ScopedPlatformHandleVectorPtr handles;
handles.reset(new PlatformHandleVector(1));
handles->at(0) = handle.release();
// This may legitimately fail on Windows if the client process is in another
// session, e.g., is an elevated process.
if (!PrepareHandlesForClient(handles.get()))
return false;
message->SetHandles(std::move(handles));
channel_->Write(std::move(message));
return true;
}
#if defined(OS_WIN)
void BrokerHost::SendNamedChannel(const base::StringPiece16& pipe_name) {
InitData* data;
base::char16* name_data;
Channel::MessagePtr message = CreateBrokerMessage(
BrokerMessageType::INIT, 0, sizeof(*name_data) * pipe_name.length(),
&data, reinterpret_cast<void**>(&name_data));
data->pipe_name_length = static_cast<uint32_t>(pipe_name.length());
std::copy(pipe_name.begin(), pipe_name.end(), name_data);
channel_->Write(std::move(message));
}
#endif // defined(OS_WIN)
void BrokerHost::OnBufferRequest(uint32_t num_bytes) {
scoped_refptr<PlatformSharedBuffer> read_only_buffer;
scoped_refptr<PlatformSharedBuffer> buffer =
PlatformSharedBuffer::Create(num_bytes);
if (buffer)
read_only_buffer = buffer->CreateReadOnlyDuplicate();
if (!read_only_buffer)
buffer = nullptr;
Channel::MessagePtr message = CreateBrokerMessage(
BrokerMessageType::BUFFER_RESPONSE, buffer ? 2 : 0, nullptr);
if (buffer) {
ScopedPlatformHandleVectorPtr handles;
handles.reset(new PlatformHandleVector(2));
handles->at(0) = buffer->PassPlatformHandle().release();
handles->at(1) = read_only_buffer->PassPlatformHandle().release();
PrepareHandlesForClient(handles.get());
message->SetHandles(std::move(handles));
}
channel_->Write(std::move(message));
}
void BrokerHost::OnChannelMessage(const void* payload,
size_t payload_size,
ScopedPlatformHandleVectorPtr handles) {
if (payload_size < sizeof(BrokerMessageHeader))
return;
const BrokerMessageHeader* header =
static_cast<const BrokerMessageHeader*>(payload);
switch (header->type) {
case BrokerMessageType::BUFFER_REQUEST:
if (payload_size ==
sizeof(BrokerMessageHeader) + sizeof(BufferRequestData)) {
const BufferRequestData* request =
reinterpret_cast<const BufferRequestData*>(header + 1);
OnBufferRequest(request->size);
}
break;
default:
LOG(ERROR) << "Unexpected broker message type: " << header->type;
break;
}
}
void BrokerHost::OnChannelError() { delete this; }
void BrokerHost::WillDestroyCurrentMessageLoop() { delete this; }
} // namespace edk
} // namespace mojo
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