Initialize IPC:ChannelHandle from existing HANDLE

ipc/ipc_channel_handle.h

 // Copyright (c) 2011 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 IPC_IPC_CHANNEL_HANDLE_H_
 #define IPC_IPC_CHANNEL_HANDLE_H_
 #pragma once
 
 #include <string>
 
 #include "build/build_config.h"
 
+#if defined(OS_WIN)
+#include "base/win/scoped_handle.h"
+#endif
 #if defined(OS_POSIX)
 #include "base/file_descriptor_posix.h"
 #endif
 
 // On Windows, any process can create an IPC channel and others can fetch
 // it by name.  We pass around the channel names over IPC.
 // On POSIX, we instead pass around handles to channel endpoints via IPC.

[cpu_(ooo_6.6-7.5), 2012/01/19 20:56:05]

With this change we change the behavior significantly, no longer you can pass a
ChannelHandle over ipc to another process and expect that it can open it.

 // When it's time to IPC a new channel endpoint around, we send both the
 // channel name as well as a base::FileDescriptor, which is itself a special
 // type that knows how to copy a socket endpoint over IPC.
 //
 // In sum, when passing a handle to a channel over IPC, use this data structure
 // to work on both Windows and POSIX.
 
 namespace IPC {
 
 struct ChannelHandle {
   // Note that serialization for this object is defined in the ParamTraits
   // template specialization in ipc_message_utils.h.
   ChannelHandle() {}
   // The name that is passed in should be an absolute path for Posix.
   // Otherwise there may be a problem in IPC communication between
   // processes with different working directories.
   ChannelHandle(const std::string& n) : name(n) {}
   ChannelHandle(const char* n) : name(n) {}
+#if defined(OS_WIN)
+  ChannelHandle(HANDLE h) : pipe(h) {}
+  ChannelHandle(const ChannelHandle& other) {
+    Assign(other);
+  }
+  ChannelHandle& operator=(const ChannelHandle& other) {
+    Assign(other);
+    return *this;
+  }
+  void Assign(const ChannelHandle& other) {
+    name = other.name;
+    HANDLE copy = NULL;
+    DuplicateHandle(GetCurrentProcess(), other.pipe, GetCurrentProcess(),
+                    &copy, 0, FALSE, DUPLICATE_SAME_ACCESS);
+    pipe.Set(copy);
+  }
+#endif
 #if defined(OS_POSIX)
   ChannelHandle(const std::string& n, const base::FileDescriptor& s)
       : name(n), socket(s) {}
 #endif  // defined(OS_POSIX)
 
   std::string name;
 #if defined(OS_POSIX)
   base::FileDescriptor socket;
 #endif  // defined(OS_POSIX)
+#if defined(OS_WIN)
+  base::win::ScopedHandle pipe;

[cpu_(ooo_6.6-7.5), 2012/01/19 20:56:05]

so base::FileDescriptor does not close the descriptor on destruction, in other
words is not a scoped handle, so I am thinking that here you should just have
the raw handle so the behavior is the same.

This will also eliminate the duplicatehandle part.

+#endif
 
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_CHANNEL_HANDLE_H_