Capability: passing fds over IPC

chrome/common/ipc_channel_posix.h

 // Copyright (c) 2008 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.
 
 #ifndef CHROME_COMMON_IPC_CHANNEL_POSIX_H_
 #define CHROME_COMMON_IPC_CHANNEL_POSIX_H_
 
 #include "chrome/common/ipc_channel.h"
 
+#include <sys/socket.h>  // for CMSG macros
+
 #include <queue>
 #include <string>
+#include <vector>
 
 #include "base/message_loop.h"
+#include "chrome/common/file_descriptor_posix.h"
 
 namespace IPC {
 
 class Channel::ChannelImpl : public MessageLoopForIO::Watcher {
  public:
   // Mirror methods of Channel, see ipc_channel.h for description.
   ChannelImpl(const std::wstring& channel_id, Mode mode, Listener* listener);
   ~ChannelImpl() { Close(); }
   bool Connect();
   void Close();
@@ skipping 37 matching lines @@
   std::string pipe_name_;
 
   Listener* listener_;
 
   // Messages to be sent are queued here.
   std::queue<Message*> output_queue_;
 
   // We read from the pipe into this buffer
   char input_buf_[Channel::kReadBufferSize];
 
+  enum {
+    // We assume a worst case: kReadBufferSize bytes of messages, where each
+    // message has no payload and a full complement of descriptors.
+    MAX_READ_FDS = (Channel::kReadBufferSize / sizeof(IPC::Message::Header)) *
+                   DescriptorSet::MAX_DESCRIPTORS_PER_MESSAGE,
+  };
+
+  // This is a control message buffer large enough to hold kMaxReadFDs
+  char input_cmsg_buf_[CMSG_SPACE(sizeof(int) * MAX_READ_FDS)];
+
   // Large messages that span multiple pipe buffers, get built-up using
   // this buffer.
   std::string input_overflow_buf_;
+  std::vector<int> input_overflow_fds_;
 
   // In server-mode, we have to wait for the client to connect before we
   // can begin reading.  We make use of the input_state_ when performing
   // the connect operation in overlapped mode.
   bool waiting_connect_;
 
   // This flag is set when processing incoming messages.  It is used to
   // avoid recursing through ProcessIncomingMessages, which could cause
   // problems.  TODO(darin): make this unnecessary
   bool processing_incoming_;
 
   ScopedRunnableMethodFactory<ChannelImpl> factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ChannelImpl);
 };
 
 }  // namespace IPC
 
 #endif  // CHROME_COMMON_IPC_CHANNEL_POSIX_H_