1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef MOJO_EMBEDDER_PLATFORM_CHANNEL_PAIR_H_ 6 #define MOJO_EMBEDDER_PLATFORM_CHANNEL_PAIR_H_ 7 8 #include "base/macros.h" 9 #include "base/memory/scoped_ptr.h" 10 #include "base/process/launch.h" 11 #include "build/build_config.h" 12 #include "mojo/embedder/scoped_platform_handle.h" 13 #include "mojo/system/system_impl_export.h" 14 15 namespace base { 16 class CommandLine; 17 } 18 19 namespace mojo { 20 namespace embedder { 21 22 // It would be nice to refactor base/process/launch.h to have a more platform- 23 // independent way of representing handles that are passed to child processes. 24 #if defined(OS_WIN) 25 typedef base::HandlesToInheritVector HandlePassingInformation; 26 #elif defined(OS_POSIX) 27 typedef base::FileHandleMappingVector HandlePassingInformation; 28 #else 29 #error "Unsupported." 30 #endif 31 32 // This is used to create a pair of |PlatformHandle|s that are connected by a 33 // suitable (platform-specific) bidirectional "pipe" (e.g., socket on POSIX, 34 // named pipe on Windows). The resulting handles can then be used in the same 35 // process (e.g., in tests) or between processes. (The "server" handle is the 36 // one that will be used in the process that created the pair, whereas the 37 // "client" handle is the one that will be used in a different process.) 38 // 39 // This class provides facilities for passing the client handle to a child 40 // process. The parent should call |PrepareToPassClientHandlelToChildProcess()| 41 // to get the data needed to do this, spawn the child using that data, and then 42 // call |ChildProcessLaunched()|. Note that on Windows this facility (will) only 43 // work on Vista and later (TODO(vtl)). 44 // 45 // Note: |PlatformChannelPair()|, |PassClientHandleFromParentProcess()| and 46 // |PrepareToPassClientHandleToChildProcess()| have platform-specific 47 // implementations. 48 // 49 // Note: On POSIX platforms, to write to the "pipe", use 50 // |PlatformChannel{Write,Writev}()| (from platform_channel_utils_posix.h) 51 // instead of |write()|, |writev()|, etc. Otherwise, you have to worry about 52 // platform differences in suppressing |SIGPIPE|. 53 class MOJO_SYSTEM_IMPL_EXPORT PlatformChannelPair { 54 public: 55 PlatformChannelPair(); 56 ~PlatformChannelPair(); 57 58 ScopedPlatformHandle PassServerHandle(); 59 60 // For in-process use (e.g., in tests or to pass over another channel). 61 ScopedPlatformHandle PassClientHandle(); 62 63 // To be called in the child process, after the parent process called 64 // |PrepareToPassClientHandleToChildProcess()| and launched the child (using 65 // the provided data), to create a client handle connected to the server 66 // handle (in the parent process). 67 static ScopedPlatformHandle PassClientHandleFromParentProcess( 68 const base::CommandLine& command_line); 69 70 // Prepares to pass the client channel to a new child process, to be launched 71 // using |LaunchProcess()| (from base/launch.h). Modifies |*command_line| and 72 // |*handle_passing_info| as needed. 73 // Note: For Windows, this method only works on Vista and later. 74 void PrepareToPassClientHandleToChildProcess( 75 base::CommandLine* command_line, 76 HandlePassingInformation* handle_passing_info) const; 77 78 // To be called once the child process has been successfully launched, to do 79 // any cleanup necessary. 80 void ChildProcessLaunched(); 81 82 private: 83 static const char kMojoPlatformChannelHandleSwitch[]; 84 85 ScopedPlatformHandle server_handle_; 86 ScopedPlatformHandle client_handle_; 87 88 DISALLOW_COPY_AND_ASSIGN(PlatformChannelPair); 89 }; 90 91 } // namespace embedder 92 } // namespace mojo 93 94 #endif // MOJO_EMBEDDER_PLATFORM_CHANNEL_PAIR_H_ 95
