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 #include "mojo/shell/app_child_process.h" 6 7 #include "base/bind.h" 8 #include "base/callback_helpers.h" 9 #include "base/files/file_path.h" 10 #include "base/location.h" 11 #include "base/logging.h" 12 #include "base/macros.h" 13 #include "base/memory/ref_counted.h" 14 #include "base/message_loop/message_loop.h" 15 #include "base/scoped_native_library.h" 16 #include "base/single_thread_task_runner.h" 17 #include "base/synchronization/waitable_event.h" 18 #include "base/threading/thread.h" 19 #include "base/threading/thread_checker.h" 20 #include "mojo/common/message_pump_mojo.h" 21 #include "mojo/embedder/embedder.h" 22 #include "mojo/public/cpp/system/core.h" 23 #include "mojo/shell/app_child_process.mojom.h" 24 25 namespace mojo { 26 namespace shell { 27 28 namespace { 29 30 // Blocker --------------------------------------------------------------------- 31 32 // Blocks a thread until another thread unblocks it, at which point it unblocks 33 // and runs a closure provided by that thread. 34 class Blocker { 35 public: 36 class Unblocker { 37 public: 38 ~Unblocker() {} 39 40 void Unblock(base::Closure run_after) { 41 DCHECK(blocker_); 42 DCHECK(blocker_->run_after_.is_null()); 43 blocker_->run_after_ = run_after; 44 blocker_->event_.Signal(); 45 blocker_ = NULL; 46 } 47 48 private: 49 friend class Blocker; 50 Unblocker(Blocker* blocker) : blocker_(blocker) { 51 DCHECK(blocker_); 52 } 53 54 Blocker* blocker_; 55 56 // Copy and assign allowed. 57 }; 58 59 Blocker() : event_(true, false) {} 60 ~Blocker() {} 61 62 void Block() { 63 DCHECK(run_after_.is_null()); 64 event_.Wait(); 65 run_after_.Run(); 66 } 67 68 Unblocker GetUnblocker() { 69 return Unblocker(this); 70 } 71 72 private: 73 base::WaitableEvent event_; 74 base::Closure run_after_; 75 76 DISALLOW_COPY_AND_ASSIGN(Blocker); 77 }; 78 79 // AppContext ------------------------------------------------------------------ 80 81 class AppChildControllerImpl; 82 83 static void DestroyController(scoped_ptr<AppChildControllerImpl> controller) { 84 } 85 86 // Should be created and initialized on the main thread. 87 class AppContext { 88 public: 89 AppContext() 90 : io_thread_("io_thread"), 91 controller_thread_("controller_thread") {} 92 ~AppContext() {} 93 94 void Init() { 95 // Initialize Mojo before starting any threads. 96 embedder::Init(); 97 98 // Create and start our I/O thread. 99 base::Thread::Options io_thread_options(base::MessageLoop::TYPE_IO, 0); 100 CHECK(io_thread_.StartWithOptions(io_thread_options)); 101 io_runner_ = io_thread_.message_loop_proxy().get(); 102 CHECK(io_runner_); 103 104 // Create and start our controller thread. 105 base::Thread::Options controller_thread_options; 106 controller_thread_options.message_loop_type = 107 base::MessageLoop::TYPE_CUSTOM; 108 controller_thread_options.message_pump_factory = 109 base::Bind(&common::MessagePumpMojo::Create); 110 CHECK(controller_thread_.StartWithOptions(controller_thread_options)); 111 controller_runner_ = controller_thread_.message_loop_proxy().get(); 112 CHECK(controller_runner_); 113 } 114 115 void Shutdown() { 116 controller_runner_->PostTask( 117 FROM_HERE, 118 base::Bind(&DestroyController, base::Passed(&controller_))); 119 } 120 121 base::SingleThreadTaskRunner* io_runner() const { 122 return io_runner_.get(); 123 } 124 125 base::SingleThreadTaskRunner* controller_runner() const { 126 return controller_runner_.get(); 127 } 128 129 AppChildControllerImpl* controller() const { 130 return controller_.get(); 131 } 132 133 void set_controller(scoped_ptr<AppChildControllerImpl> controller) { 134 controller_ = controller.Pass(); 135 } 136 137 private: 138 // Accessed only on the controller thread. 139 // IMPORTANT: This must be BEFORE |controller_thread_|, so that the controller 140 // thread gets joined (and thus |controller_| reset) before |controller_| is 141 // destroyed. 142 scoped_ptr<AppChildControllerImpl> controller_; 143 144 base::Thread io_thread_; 145 scoped_refptr<base::SingleThreadTaskRunner> io_runner_; 146 147 base::Thread controller_thread_; 148 scoped_refptr<base::SingleThreadTaskRunner> controller_runner_; 149 150 DISALLOW_COPY_AND_ASSIGN(AppContext); 151 }; 152 153 // AppChildControllerImpl ------------------------------------------------------ 154 155 class AppChildControllerImpl : public InterfaceImpl<AppChildController> { 156 public: 157 virtual ~AppChildControllerImpl() { 158 DCHECK(thread_checker_.CalledOnValidThread()); 159 160 // TODO(vtl): Pass in the result from |MainMain()|. 161 client()->AppCompleted(MOJO_RESULT_UNIMPLEMENTED); 162 } 163 164 // To be executed on the controller thread. Creates the |AppChildController|, 165 // etc. 166 static void Init( 167 AppContext* app_context, 168 embedder::ScopedPlatformHandle platform_channel, 169 const Blocker::Unblocker& unblocker) { 170 DCHECK(app_context); 171 DCHECK(platform_channel.is_valid()); 172 173 DCHECK(!app_context->controller()); 174 175 scoped_ptr<AppChildControllerImpl> impl( 176 new AppChildControllerImpl(app_context, unblocker)); 177 178 ScopedMessagePipeHandle host_message_pipe(embedder::CreateChannel( 179 platform_channel.Pass(), 180 app_context->io_runner(), 181 base::Bind(&AppChildControllerImpl::DidCreateChannel, 182 base::Unretained(impl.get())), 183 base::MessageLoopProxy::current())); 184 185 BindToPipe(impl.get(), host_message_pipe.Pass()); 186 187 app_context->set_controller(impl.Pass()); 188 } 189 190 virtual void OnConnectionError() OVERRIDE { 191 // TODO(darin): How should we handle a connection error here? 192 } 193 194 // |AppChildController| methods: 195 virtual void StartApp(const String& app_path, 196 ScopedMessagePipeHandle service) OVERRIDE { 197 DVLOG(2) << "AppChildControllerImpl::StartApp(" << app_path << ", ...)"; 198 DCHECK(thread_checker_.CalledOnValidThread()); 199 200 unblocker_.Unblock(base::Bind(&AppChildControllerImpl::StartAppOnMainThread, 201 base::FilePath::FromUTF8Unsafe(app_path), 202 base::Passed(&service))); 203 } 204 205 private: 206 AppChildControllerImpl(AppContext* app_context, 207 const Blocker::Unblocker& unblocker) 208 : app_context_(app_context), 209 unblocker_(unblocker), 210 channel_info_(NULL) { 211 } 212 213 // Callback for |embedder::CreateChannel()|. 214 void DidCreateChannel(embedder::ChannelInfo* channel_info) { 215 DVLOG(2) << "AppChildControllerImpl::DidCreateChannel()"; 216 DCHECK(thread_checker_.CalledOnValidThread()); 217 channel_info_ = channel_info; 218 } 219 220 static void StartAppOnMainThread(const base::FilePath& app_path, 221 ScopedMessagePipeHandle service) { 222 // TODO(vtl): This is copied from in_process_dynamic_service_runner.cc. 223 DVLOG(2) << "Loading/running Mojo app from " << app_path.value() 224 << " out of process"; 225 226 do { 227 base::NativeLibraryLoadError load_error; 228 base::ScopedNativeLibrary app_library( 229 base::LoadNativeLibrary(app_path, &load_error)); 230 if (!app_library.is_valid()) { 231 LOG(ERROR) << "Failed to load library (error: " << load_error.ToString() 232 << ")"; 233 break; 234 } 235 236 typedef MojoResult (*MojoMainFunction)(MojoHandle); 237 MojoMainFunction main_function = reinterpret_cast<MojoMainFunction>( 238 app_library.GetFunctionPointer("MojoMain")); 239 if (!main_function) { 240 LOG(ERROR) << "Entrypoint MojoMain not found"; 241 break; 242 } 243 244 // TODO(vtl): Report the result back to our parent process. 245 // |MojoMain()| takes ownership of the service handle. 246 MojoResult result = main_function(service.release().value()); 247 if (result < MOJO_RESULT_OK) 248 LOG(ERROR) << "MojoMain returned an error: " << result; 249 } while (false); 250 } 251 252 base::ThreadChecker thread_checker_; 253 AppContext* const app_context_; 254 Blocker::Unblocker unblocker_; 255 256 embedder::ChannelInfo* channel_info_; 257 258 DISALLOW_COPY_AND_ASSIGN(AppChildControllerImpl); 259 }; 260 261 } // namespace 262 263 // AppChildProcess ------------------------------------------------------------- 264 265 AppChildProcess::AppChildProcess() { 266 } 267 268 AppChildProcess::~AppChildProcess() { 269 } 270 271 void AppChildProcess::Main() { 272 DVLOG(2) << "AppChildProcess::Main()"; 273 274 AppContext app_context; 275 app_context.Init(); 276 277 Blocker blocker; 278 app_context.controller_runner()->PostTask( 279 FROM_HERE, 280 base::Bind(&AppChildControllerImpl::Init, base::Unretained(&app_context), 281 base::Passed(platform_channel()), blocker.GetUnblocker())); 282 // This will block, then run whatever the controller wants. 283 blocker.Block(); 284 285 app_context.Shutdown(); 286 } 287 288 } // namespace shell 289 } // namespace mojo 290