Add multiplexing of message pipes in the new EDK.

mojo/edk/system/child_broker.cc

Index: mojo/edk/system/child_broker.cc
diff --git a/mojo/edk/system/child_broker.cc b/mojo/edk/system/child_broker.cc
index 7d7b4c664eea16cb1f2e0fcaf811ffab96a8e912..32e4c4703d957ec4f12cc3a11d2a31e01dad6dab 100644
--- a/mojo/edk/system/child_broker.cc
+++ b/mojo/edk/system/child_broker.cc
@@ -4,9 +4,13 @@
 
 #include "mojo/edk/system/child_broker.h"
 
+#include "base/bind.h"
 #include "base/logging.h"
 #include "mojo/edk/embedder/embedder_internal.h"
+#include "mojo/edk/embedder/platform_channel_pair.h"
 #include "mojo/edk/system/broker_messages.h"
+#include "mojo/edk/system/message_pipe_dispatcher.h"
+#include "mojo/edk/system/routed_raw_channel.h"
 
 namespace mojo {
 namespace edk {
@@ -17,23 +21,41 @@ ChildBroker* ChildBroker::GetInstance() {
 }
 
 void ChildBroker::SetChildBrokerHostHandle(ScopedPlatformHandle handle)  {
-  handle_ = handle.Pass();
+  ScopedPlatformHandle parent_async_channel_handle;
+#if defined(OS_POSIX)
+  parent_async_channel_handle = handle.Pass();
+#else
+  // On Windows we have two pipes to the parent. The first is for the token
+  // exchange for creating and passing handles, since the child needs the
+  // parent's help if it is sandboxed. The second is the same as POSIX, which is
+  // used for multiplexing related messages. So on Windows, we send the second
+  // pipe as the first string over the first one.
+  parent_sync_channel_ = handle.Pass();
+
+  HANDLE parent_handle = INVALID_HANDLE_VALUE;
+  DWORD bytes_read = 0;
+  BOOL rv = ReadFile(parent_sync_channel_.get().handle, &parent_handle,
+                     sizeof(parent_handle), &bytes_read, NULL);
+  DCHECK(rv);

[Tom Sepez, 2015/12/04 17:59:43]

Do we want something stronger than a DCHECK here?

[jam, 2015/12/05 00:09:34]

sure, changed it to CHECK so that we know if this fails (which would be
catastrophic)

+  parent_async_channel_handle.reset(PlatformHandle(parent_handle));
+#endif
+
+  parent_async_channel_ =
+      RawChannel::Create(parent_async_channel_handle.Pass());
+  internal::g_io_thread_task_runner->PostTask(
+      FROM_HERE,
+      base::Bind(&RawChannel::Init, base::Unretained(parent_async_channel_),
+                 this));
+
   lock_.Unlock();
 }
 
 #if defined(OS_WIN)
 void ChildBroker::CreatePlatformChannelPair(
     ScopedPlatformHandle* server, ScopedPlatformHandle* client) {
-  BrokerMessage message;
-  message.size = kBrokerMessageHeaderSize;
-  message.id = CREATE_PLATFORM_CHANNEL_PAIR;
-
-  uint32_t response_size = 2 * sizeof(HANDLE);
-  HANDLE handles[2];
-  if (WriteAndReadResponse(&message, handles, response_size)) {
-    server->reset(PlatformHandle(handles[0]));
-    client->reset(PlatformHandle(handles[1]));
-  }
+  lock_.Lock();
+  CreatePlatformChannelPairNoLock(server, client);
+  lock_.Unlock();
 }
 
 void ChildBroker::HandleToToken(const PlatformHandle* platform_handles,
@@ -49,7 +71,9 @@ void ChildBroker::HandleToToken(const PlatformHandle* platform_handles,
     message->handles[i] = platform_handles[i].handle;
 
   uint32_t response_size = static_cast<int>(count) * sizeof(uint64_t);
+  lock_.Lock();
   WriteAndReadResponse(message, tokens, response_size);
+  lock_.Unlock();
 }
 
 void ChildBroker::TokenToHandle(const uint64_t* tokens,
@@ -67,14 +91,85 @@ void ChildBroker::TokenToHandle(const uint64_t* tokens,
   std::vector<HANDLE> handles_temp(count);
   uint32_t response_size =
       static_cast<uint32_t>(handles_temp.size()) * sizeof(HANDLE);
+  lock_.Lock();
   if (WriteAndReadResponse(message, &handles_temp[0], response_size)) {
     for (uint32_t i = 0; i < count; ++i)
       handles[i].handle = handles_temp[i];
+  lock_.Unlock();
   }
 }
 #endif
 
-ChildBroker::ChildBroker() {
+void ChildBroker::ConnectMessagePipe(uint64_t pipe_id,
+                                     MessagePipeDispatcher* message_pipe) {
+  DCHECK(internal::g_io_thread_task_runner->RunsTasksOnCurrentThread());
+  lock_.Lock();
+
+  ConnectMessagePipeMessage data;
+  data.pipe_id = pipe_id;
+  if (pending_connects_.find(pipe_id) != pending_connects_.end()) {
+    // Both ends of the message pipe are in the same process.
+    // First, tell the browser side that to remove its bookkeeping for a pending
+    // connect, since it'll never get the other side.
+
+    data.type = CANCEL_CONNECT_MESSAGE_PIPE;
+    scoped_ptr<MessageInTransit> message(new MessageInTransit(
+        MessageInTransit::Type::MESSAGE, sizeof(data), &data));
+    parent_async_channel_->WriteMessage(message.Pass());
+
+    if (!in_process_pipes_channel1_) {
+      ScopedPlatformHandle server_handle, client_handle;
+#if defined(OS_WIN)
+      CreatePlatformChannelPairNoLock(&server_handle, &client_handle);
+#else
+      PlatformChannelPair channel_pair;
+      server_handle = channel_pair.PassServerHandle();
+      client_handle = channel_pair.PassClientHandle();
+#endif
+      in_process_pipes_channel1_ = new RoutedRawChannel(
+          server_handle.Pass(),
+          base::Bind(&ChildBroker::ChannelDestructed, base::Unretained(this)));
+      in_process_pipes_channel2_ = new RoutedRawChannel(
+          client_handle.Pass(),
+          base::Bind(&ChildBroker::ChannelDestructed, base::Unretained(this)));
+    }
+
+    connected_pipes_[pending_connects_[pipe_id]] = in_process_pipes_channel1_;
+    connected_pipes_[message_pipe] = in_process_pipes_channel2_;
+    in_process_pipes_channel1_->AddRoute(pipe_id, pending_connects_[pipe_id]);
+    in_process_pipes_channel2_->AddRoute(pipe_id, message_pipe);
+    pending_connects_[pipe_id]->GotNonTransferableChannel(
+        in_process_pipes_channel1_->channel());
+    message_pipe->GotNonTransferableChannel(
+        in_process_pipes_channel2_->channel());
+
+    pending_connects_.erase(pipe_id);
+    lock_.Unlock();
+    return;
+  }
+
+  data.type = CONNECT_MESSAGE_PIPE;
+  scoped_ptr<MessageInTransit> message(new MessageInTransit(
+      MessageInTransit::Type::MESSAGE, sizeof(data), &data));
+  pending_connects_[pipe_id] = message_pipe;
+  parent_async_channel_->WriteMessage(message.Pass());
+
+  lock_.Unlock();
+}
+
+void ChildBroker::CloseMessagePipe(
+    uint64_t pipe_id, MessagePipeDispatcher* message_pipe) {
+  DCHECK(internal::g_io_thread_task_runner->RunsTasksOnCurrentThread());
+  lock_.Lock();
+  CHECK(connected_pipes_.find(message_pipe) != connected_pipes_.end());
+  connected_pipes_[message_pipe]->RemoveRoute(pipe_id, message_pipe);
+  connected_pipes_.erase(message_pipe);
+  lock_.Unlock();
+}
+
+ChildBroker::ChildBroker()
+    : in_process_pipes_channel1_(nullptr),
+      in_process_pipes_channel2_(nullptr) {
   DCHECK(!internal::g_broker);
   internal::g_broker = this;
   // Block any threads from calling this until we have a pipe to the parent.
@@ -84,18 +179,76 @@ ChildBroker::ChildBroker() {
 ChildBroker::~ChildBroker() {
 }
 
+void ChildBroker::OnReadMessage(
+    const MessageInTransit::View& message_view,
+    ScopedPlatformHandleVectorPtr platform_handles) {
+  DCHECK(internal::g_io_thread_task_runner->RunsTasksOnCurrentThread());
+  lock_.Lock();
+  MultiplexMessages type =
+      *static_cast<const MultiplexMessages*>(message_view.bytes());
+  if (type == CONNECT_TO_PROCESS) {
+    DCHECK_EQ(platform_handles->size(), 1u);
+    ScopedPlatformHandle handle((*platform_handles.get())[0]);
+    (*platform_handles.get())[0] = PlatformHandle();
+
+    const ConnectToProcessMessage* message =
+        static_cast<const ConnectToProcessMessage*>(message_view.bytes());
+
+    CHECK(channels_.find(message->process_id) == channels_.end());
+    channels_[message->process_id] = new RoutedRawChannel(
+        handle.Pass(),
+        base::Bind(&ChildBroker::ChannelDestructed, base::Unretained(this)));
+  } else if (type == PEER_PIPE_CONNECTED) {
+    DCHECK(!platform_handles);
+    const PeerPipeConnectedMessage* message =
+        static_cast<const PeerPipeConnectedMessage*>(message_view.bytes());
+
+    uint64_t pipe_id = message->pipe_id;
+    uint64_t peer_pid = message->process_id;
+
+    CHECK(channels_.find(peer_pid) != channels_.end());
+    CHECK(pending_connects_.find(pipe_id) != pending_connects_.end());
+    MessagePipeDispatcher* pipe = pending_connects_[pipe_id];
+    pending_connects_.erase(pipe_id);
+    CHECK(connected_pipes_.find(pipe) == connected_pipes_.end());
+    connected_pipes_[pipe] = channels_[peer_pid];
+    channels_[peer_pid]->AddRoute(pipe_id, pipe);
+    pipe->GotNonTransferableChannel(channels_[peer_pid]->channel());
+  } else {
+    NOTREACHED();
+  }
+
+  lock_.Unlock();
+}
+
+void ChildBroker::OnError(Error error) {
+  // The parent process shut down.
+}
+
+void ChildBroker::ChannelDestructed(RoutedRawChannel* channel) {
+  DCHECK(internal::g_io_thread_task_runner->RunsTasksOnCurrentThread());
+  lock_.Lock();
+  for (auto it : channels_) {
+    if (it.second == channel) {
+      channels_.erase(it.first);
+      break;
+    }
+  }
+  lock_.Unlock();
+}
+
+#if defined(OS_WIN)
+
 bool ChildBroker::WriteAndReadResponse(BrokerMessage* message,
                                        void* response,
                                        uint32_t response_size) {
-  lock_.Lock();
-  CHECK(handle_.is_valid());
+  CHECK(parent_sync_channel_.is_valid());
 
   bool result = true;
-#if defined(OS_WIN)
   DWORD bytes_written = 0;
   // This will always write in one chunk per
   // https://msdn.microsoft.com/en-us/library/windows/desktop/aa365150.aspx.
-  BOOL rv = WriteFile(handle_.get().handle, message, message->size,
+  BOOL rv = WriteFile(parent_sync_channel_.get().handle, message, message->size,
                       &bytes_written, NULL);
   if (!rv || bytes_written != message->size) {
     LOG(ERROR) << "Child token serializer couldn't write message.";
@@ -103,8 +256,8 @@ bool ChildBroker::WriteAndReadResponse(BrokerMessage* message,
   } else {
     while (response_size) {
       DWORD bytes_read = 0;
-      rv = ReadFile(handle_.get().handle, response, response_size, &bytes_read,
-                    NULL);
+      rv = ReadFile(parent_sync_channel_.get().handle, response, response_size,
+                    &bytes_read, NULL);
       if (!rv) {
         LOG(ERROR) << "Child token serializer couldn't read result.";
         result = false;
@@ -114,12 +267,25 @@ bool ChildBroker::WriteAndReadResponse(BrokerMessage* message,
       response = static_cast<char*>(response) + bytes_read;
     }
   }
-#endif
-
-  lock_.Unlock();
 
   return result;
 }
 
+void ChildBroker::CreatePlatformChannelPairNoLock(
+    ScopedPlatformHandle* server, ScopedPlatformHandle* client) {
+  BrokerMessage message;
+  message.size = kBrokerMessageHeaderSize;
+  message.id = CREATE_PLATFORM_CHANNEL_PAIR;
+
+  uint32_t response_size = 2 * sizeof(HANDLE);
+  HANDLE handles[2];
+  if (WriteAndReadResponse(&message, handles, response_size)) {
+    server->reset(PlatformHandle(handles[0]));
+    client->reset(PlatformHandle(handles[1]));
+  }
+}
+
+#endif
+
 }  // namespace edk
 }  // namespace mojo