src/dbus/bus.cc

   1 // Copyright (c) 2012 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 "dbus/bus.h"
   6
   7 #include "base/bind.h"
   8 #include "base/logging.h"
   9 #include "base/message_loop/message_loop.h"
  10 #include "base/message_loop/message_loop_proxy.h"
  11 #include "base/stl_util.h"
  12 #include "base/strings/stringprintf.h"
  13 #include "base/threading/thread.h"
  14 #include "base/threading/thread_restrictions.h"
  15 #include "base/time/time.h"
  16 #include "dbus/exported_object.h"
  17 #include "dbus/message.h"
  18 #include "dbus/object_manager.h"
  19 #include "dbus/object_path.h"
  20 #include "dbus/object_proxy.h"
  21 #include "dbus/scoped_dbus_error.h"
  22
  23 namespace dbus {
  24
  25 namespace {
  26
  27 const char kDisconnectedSignal[] = "Disconnected";
  28 const char kDisconnectedMatchRule[] =
  29     "type='signal', path='/org/freedesktop/DBus/Local',"
  30     "interface='org.freedesktop.DBus.Local', member='Disconnected'";
  31
  32 // The NameOwnerChanged member in org.freedesktop.DBus
  33 const char kNameOwnerChangedSignal[] = "NameOwnerChanged";
  34
  35 // The match rule used to filter for changes to a given service name owner.
  36 const char kServiceNameOwnerChangeMatchRule[] =
  37     "type='signal',interface='org.freedesktop.DBus',"
  38     "member='NameOwnerChanged',path='/org/freedesktop/DBus',"
  39     "sender='org.freedesktop.DBus',arg0='%s'";
  40
  41 // The class is used for watching the file descriptor used for D-Bus
  42 // communication.
  43 class Watch : public base::MessagePumpLibevent::Watcher {
  44  public:
  45   explicit Watch(DBusWatch* watch)
  46       : raw_watch_(watch) {
  47     dbus_watch_set_data(raw_watch_, this, NULL);
  48   }
  49
  50   virtual ~Watch() {
  51     dbus_watch_set_data(raw_watch_, NULL, NULL);
  52   }
  53
  54   // Returns true if the underlying file descriptor is ready to be watched.
  55   bool IsReadyToBeWatched() {
  56     return dbus_watch_get_enabled(raw_watch_);
  57   }
  58
  59   // Starts watching the underlying file descriptor.
  60   void StartWatching() {
  61     const int file_descriptor = dbus_watch_get_unix_fd(raw_watch_);
  62     const int flags = dbus_watch_get_flags(raw_watch_);
  63
  64     base::MessageLoopForIO::Mode mode = base::MessageLoopForIO::WATCH_READ;
  65     if ((flags & DBUS_WATCH_READABLE) && (flags & DBUS_WATCH_WRITABLE))
  66       mode = base::MessageLoopForIO::WATCH_READ_WRITE;
  67     else if (flags & DBUS_WATCH_READABLE)
  68       mode = base::MessageLoopForIO::WATCH_READ;
  69     else if (flags & DBUS_WATCH_WRITABLE)
  70       mode = base::MessageLoopForIO::WATCH_WRITE;
  71     else
  72       NOTREACHED();
  73
  74     const bool persistent = true;  // Watch persistently.
  75     const bool success = base::MessageLoopForIO::current()->WatchFileDescriptor(
  76         file_descriptor, persistent, mode, &file_descriptor_watcher_, this);
  77     CHECK(success) << "Unable to allocate memory";
  78   }
  79
  80   // Stops watching the underlying file descriptor.
  81   void StopWatching() {
  82     file_descriptor_watcher_.StopWatchingFileDescriptor();
  83   }
  84
  85  private:
  86   // Implement MessagePumpLibevent::Watcher.
  87   virtual void OnFileCanReadWithoutBlocking(int file_descriptor) OVERRIDE {
  88     const bool success = dbus_watch_handle(raw_watch_, DBUS_WATCH_READABLE);
  89     CHECK(success) << "Unable to allocate memory";
  90   }
  91
  92   // Implement MessagePumpLibevent::Watcher.
  93   virtual void OnFileCanWriteWithoutBlocking(int file_descriptor) OVERRIDE {
  94     const bool success = dbus_watch_handle(raw_watch_, DBUS_WATCH_WRITABLE);
  95     CHECK(success) << "Unable to allocate memory";
  96   }
  97
  98   DBusWatch* raw_watch_;
  99   base::MessagePumpLibevent::FileDescriptorWatcher file_descriptor_watcher_;
 100 };
 101
 102 // The class is used for monitoring the timeout used for D-Bus method
 103 // calls.
 104 //
 105 // Unlike Watch, Timeout is a ref counted object, to ensure that |this| of
 106 // the object is is alive when HandleTimeout() is called. It's unlikely
 107 // but it may be possible that HandleTimeout() is called after
 108 // Bus::OnRemoveTimeout(). That's why we don't simply delete the object in
 109 // Bus::OnRemoveTimeout().
 110 class Timeout : public base::RefCountedThreadSafe<Timeout> {
 111  public:
 112   explicit Timeout(DBusTimeout* timeout)
 113       : raw_timeout_(timeout),
 114         monitoring_is_active_(false),
 115         is_completed(false) {
 116     dbus_timeout_set_data(raw_timeout_, this, NULL);
 117     AddRef();  // Balanced on Complete().
 118   }
 119
 120   // Returns true if the timeout is ready to be monitored.
 121   bool IsReadyToBeMonitored() {
 122     return dbus_timeout_get_enabled(raw_timeout_);
 123   }
 124
 125   // Starts monitoring the timeout.
 126   void StartMonitoring(Bus* bus) {
 127     bus->GetDBusTaskRunner()->PostDelayedTask(
 128         FROM_HERE,
 129         base::Bind(&Timeout::HandleTimeout, this),
 130         GetInterval());
 131     monitoring_is_active_ = true;
 132   }
 133
 134   // Stops monitoring the timeout.
 135   void StopMonitoring() {
 136     // We cannot take back the delayed task we posted in
 137     // StartMonitoring(), so we just mark the monitoring is inactive now.
 138     monitoring_is_active_ = false;
 139   }
 140
 141   // Returns the interval.
 142   base::TimeDelta GetInterval() {
 143     return base::TimeDelta::FromMilliseconds(
 144         dbus_timeout_get_interval(raw_timeout_));
 145   }
 146
 147   // Cleans up the raw_timeout and marks that timeout is completed.
 148   // See the class comment above for why we are doing this.
 149   void Complete() {
 150     dbus_timeout_set_data(raw_timeout_, NULL, NULL);
 151     is_completed = true;
 152     Release();
 153   }
 154
 155  private:
 156   friend class base::RefCountedThreadSafe<Timeout>;
 157   ~Timeout() {
 158   }
 159
 160   // Handles the timeout.
 161   void HandleTimeout() {
 162     // If the timeout is marked completed, we should do nothing. This can
 163     // occur if this function is called after Bus::OnRemoveTimeout().
 164     if (is_completed)
 165       return;
 166     // Skip if monitoring is canceled.
 167     if (!monitoring_is_active_)
 168       return;
 169
 170     const bool success = dbus_timeout_handle(raw_timeout_);
 171     CHECK(success) << "Unable to allocate memory";
 172   }
 173
 174   DBusTimeout* raw_timeout_;
 175   bool monitoring_is_active_;
 176   bool is_completed;
 177 };
 178
 179 }  // namespace
 180
 181 Bus::Options::Options()
 182   : bus_type(SESSION),
 183     connection_type(PRIVATE) {
 184 }
 185
 186 Bus::Options::~Options() {
 187 }
 188
 189 Bus::Bus(const Options& options)
 190     : bus_type_(options.bus_type),
 191       connection_type_(options.connection_type),
 192       dbus_task_runner_(options.dbus_task_runner),
 193       on_shutdown_(false /* manual_reset */, false /* initially_signaled */),
 194       connection_(NULL),
 195       origin_thread_id_(base::PlatformThread::CurrentId()),
 196       async_operations_set_up_(false),
 197       shutdown_completed_(false),
 198       num_pending_watches_(0),
 199       num_pending_timeouts_(0),
 200       address_(options.address),
 201       on_disconnected_closure_(options.disconnected_callback) {
 202   // This is safe to call multiple times.
 203   dbus_threads_init_default();
 204   // The origin message loop is unnecessary if the client uses synchronous
 205   // functions only.
 206   if (base::MessageLoop::current())
 207     origin_task_runner_ = base::MessageLoop::current()->message_loop_proxy();
 208 }
 209
 210 Bus::~Bus() {
 211   DCHECK(!connection_);
 212   DCHECK(owned_service_names_.empty());
 213   DCHECK(match_rules_added_.empty());
 214   DCHECK(filter_functions_added_.empty());
 215   DCHECK(registered_object_paths_.empty());
 216   DCHECK_EQ(0, num_pending_watches_);
 217   // TODO(satorux): This check fails occasionally in browser_tests for tests
 218   // that run very quickly. Perhaps something does not have time to clean up.
 219   // Despite the check failing, the tests seem to run fine. crosbug.com/23416
 220   // DCHECK_EQ(0, num_pending_timeouts_);
 221 }
 222
 223 ObjectProxy* Bus::GetObjectProxy(const std::string& service_name,
 224                                  const ObjectPath& object_path) {
 225   return GetObjectProxyWithOptions(service_name, object_path,
 226                                    ObjectProxy::DEFAULT_OPTIONS);
 227 }
 228
 229 ObjectProxy* Bus::GetObjectProxyWithOptions(const std::string& service_name,
 230                                             const ObjectPath& object_path,
 231                                             int options) {
 232   AssertOnOriginThread();
 233
 234   // Check if we already have the requested object proxy.
 235   const ObjectProxyTable::key_type key(service_name + object_path.value(),
 236                                        options);
 237   ObjectProxyTable::iterator iter = object_proxy_table_.find(key);
 238   if (iter != object_proxy_table_.end()) {
 239     return iter->second.get();
 240   }
 241
 242   scoped_refptr<ObjectProxy> object_proxy =
 243       new ObjectProxy(this, service_name, object_path, options);
 244   object_proxy_table_[key] = object_proxy;
 245
 246   return object_proxy.get();
 247 }
 248
 249 bool Bus::RemoveObjectProxy(const std::string& service_name,
 250                             const ObjectPath& object_path,
 251                             const base::Closure& callback) {
 252   return RemoveObjectProxyWithOptions(service_name, object_path,
 253                                       ObjectProxy::DEFAULT_OPTIONS,
 254                                       callback);
 255 }
 256
 257 bool Bus::RemoveObjectProxyWithOptions(const std::string& service_name,
 258                                        const ObjectPath& object_path,
 259                                        int options,
 260                                        const base::Closure& callback) {
 261   AssertOnOriginThread();
 262
 263   // Check if we have the requested object proxy.
 264   const ObjectProxyTable::key_type key(service_name + object_path.value(),
 265                                        options);
 266   ObjectProxyTable::iterator iter = object_proxy_table_.find(key);
 267   if (iter != object_proxy_table_.end()) {
 268     scoped_refptr<ObjectProxy> object_proxy = iter->second;
 269     object_proxy_table_.erase(iter);
 270     // Object is present. Remove it now and Detach on the DBus thread.
 271     GetDBusTaskRunner()->PostTask(
 272         FROM_HERE,
 273         base::Bind(&Bus::RemoveObjectProxyInternal,
 274                    this, object_proxy, callback));
 275     return true;
 276   }
 277   return false;
 278 }
 279
 280 void Bus::RemoveObjectProxyInternal(scoped_refptr<ObjectProxy> object_proxy,
 281                                     const base::Closure& callback) {
 282   AssertOnDBusThread();
 283
 284   object_proxy.get()->Detach();
 285
 286   GetOriginTaskRunner()->PostTask(FROM_HERE, callback);
 287 }
 288
 289 ExportedObject* Bus::GetExportedObject(const ObjectPath& object_path) {
 290   AssertOnOriginThread();
 291
 292   // Check if we already have the requested exported object.
 293   ExportedObjectTable::iterator iter = exported_object_table_.find(object_path);
 294   if (iter != exported_object_table_.end()) {
 295     return iter->second.get();
 296   }
 297
 298   scoped_refptr<ExportedObject> exported_object =
 299       new ExportedObject(this, object_path);
 300   exported_object_table_[object_path] = exported_object;
 301
 302   return exported_object.get();
 303 }
 304
 305 void Bus::UnregisterExportedObject(const ObjectPath& object_path) {
 306   AssertOnOriginThread();
 307
 308   // Remove the registered object from the table first, to allow a new
 309   // GetExportedObject() call to return a new object, rather than this one.
 310   ExportedObjectTable::iterator iter = exported_object_table_.find(object_path);
 311   if (iter == exported_object_table_.end())
 312     return;
 313
 314   scoped_refptr<ExportedObject> exported_object = iter->second;
 315   exported_object_table_.erase(iter);
 316
 317   // Post the task to perform the final unregistration to the D-Bus thread.
 318   // Since the registration also happens on the D-Bus thread in
 319   // TryRegisterObjectPath(), and the task runner we post to is a
 320   // SequencedTaskRunner, there is a guarantee that this will happen before any
 321   // future registration call.
 322   GetDBusTaskRunner()->PostTask(
 323       FROM_HERE,
 324       base::Bind(&Bus::UnregisterExportedObjectInternal,
 325                  this, exported_object));
 326 }
 327
 328 void Bus::UnregisterExportedObjectInternal(
 329     scoped_refptr<ExportedObject> exported_object) {
 330   AssertOnDBusThread();
 331
 332   exported_object->Unregister();
 333 }
 334
 335 ObjectManager* Bus::GetObjectManager(const std::string& service_name,
 336                                      const ObjectPath& object_path) {
 337   AssertOnOriginThread();
 338
 339   // Check if we already have the requested object manager.
 340   const ObjectManagerTable::key_type key(service_name + object_path.value());
 341   ObjectManagerTable::iterator iter = object_manager_table_.find(key);
 342   if (iter != object_manager_table_.end()) {
 343     return iter->second.get();
 344   }
 345
 346   scoped_refptr<ObjectManager> object_manager =
 347       new ObjectManager(this, service_name, object_path);
 348   object_manager_table_[key] = object_manager;
 349
 350   return object_manager.get();
 351 }
 352
 353 bool Bus::RemoveObjectManager(const std::string& service_name,
 354                               const ObjectPath& object_path,
 355                               const base::Closure& callback) {
 356   AssertOnOriginThread();
 357   DCHECK(!callback.is_null());
 358
 359   const ObjectManagerTable::key_type key(service_name + object_path.value());
 360   ObjectManagerTable::iterator iter = object_manager_table_.find(key);
 361   if (iter == object_manager_table_.end())
 362     return false;
 363
 364   // ObjectManager is present. Remove it now and CleanUp on the DBus thread.
 365   scoped_refptr<ObjectManager> object_manager = iter->second;
 366   object_manager_table_.erase(iter);
 367
 368   GetDBusTaskRunner()->PostTask(
 369       FROM_HERE,
 370       base::Bind(&Bus::RemoveObjectManagerInternal,
 371                  this, object_manager, callback));
 372
 373   return true;
 374 }
 375
 376 void Bus::RemoveObjectManagerInternal(
 377       scoped_refptr<dbus::ObjectManager> object_manager,
 378       const base::Closure& callback) {
 379   AssertOnDBusThread();
 380   DCHECK(object_manager.get());
 381
 382   object_manager->CleanUp();
 383
 384   // The ObjectManager has to be deleted on the origin thread since it was
 385   // created there.
 386   GetOriginTaskRunner()->PostTask(
 387       FROM_HERE,
 388       base::Bind(&Bus::RemoveObjectManagerInternalHelper,
 389                  this, object_manager, callback));
 390 }
 391
 392 void Bus::RemoveObjectManagerInternalHelper(
 393       scoped_refptr<dbus::ObjectManager> object_manager,
 394       const base::Closure& callback) {
 395   AssertOnOriginThread();
 396   DCHECK(object_manager.get());
 397
 398   // Release the object manager and run the callback.
 399   object_manager = NULL;
 400   callback.Run();
 401 }
 402
 403 void Bus::GetManagedObjects() {
 404   for (ObjectManagerTable::iterator iter = object_manager_table_.begin();
 405        iter != object_manager_table_.end(); ++iter) {
 406     iter->second->GetManagedObjects();
 407   }
 408 }
 409
 410 bool Bus::Connect() {
 411   // dbus_bus_get_private() and dbus_bus_get() are blocking calls.
 412   AssertOnDBusThread();
 413
 414   // Check if it's already initialized.
 415   if (connection_)
 416     return true;
 417
 418   ScopedDBusError error;
 419   if (bus_type_ == CUSTOM_ADDRESS) {
 420     if (connection_type_ == PRIVATE) {
 421       connection_ = dbus_connection_open_private(address_.c_str(), error.get());
 422     } else {
 423       connection_ = dbus_connection_open(address_.c_str(), error.get());
 424     }
 425   } else {
 426     const DBusBusType dbus_bus_type = static_cast<DBusBusType>(bus_type_);
 427     if (connection_type_ == PRIVATE) {
 428       connection_ = dbus_bus_get_private(dbus_bus_type, error.get());
 429     } else {
 430       connection_ = dbus_bus_get(dbus_bus_type, error.get());
 431     }
 432   }
 433   if (!connection_) {
 434     LOG(ERROR) << "Failed to connect to the bus: "
 435                << (error.is_set() ? error.message() : "");
 436     return false;
 437   }
 438
 439   if (bus_type_ == CUSTOM_ADDRESS) {
 440     // We should call dbus_bus_register here, otherwise unique name can not be
 441     // acquired. According to dbus specification, it is responsible to call
 442     // org.freedesktop.DBus.Hello method at the beging of bus connection to
 443     // acquire unique name. In the case of dbus_bus_get, dbus_bus_register is
 444     // called internally.
 445     if (!dbus_bus_register(connection_, error.get())) {
 446       LOG(ERROR) << "Failed to register the bus component: "
 447                  << (error.is_set() ? error.message() : "");
 448       return false;
 449     }
 450   }
 451   // We shouldn't exit on the disconnected signal.
 452   dbus_connection_set_exit_on_disconnect(connection_, false);
 453
 454   // Watch Disconnected signal.
 455   AddFilterFunction(Bus::OnConnectionDisconnectedFilter, this);
 456   AddMatch(kDisconnectedMatchRule, error.get());
 457
 458   return true;
 459 }
 460
 461 void Bus::ClosePrivateConnection() {
 462   // dbus_connection_close is blocking call.
 463   AssertOnDBusThread();
 464   DCHECK_EQ(PRIVATE, connection_type_)
 465       << "non-private connection should not be closed";
 466   dbus_connection_close(connection_);
 467 }
 468
 469 void Bus::ShutdownAndBlock() {
 470   AssertOnDBusThread();
 471
 472   if (shutdown_completed_)
 473     return;  // Already shutdowned, just return.
 474
 475   // Unregister the exported objects.
 476   for (ExportedObjectTable::iterator iter = exported_object_table_.begin();
 477        iter != exported_object_table_.end(); ++iter) {
 478     iter->second->Unregister();
 479   }
 480
 481   // Release all service names.
 482   for (std::set<std::string>::iterator iter = owned_service_names_.begin();
 483        iter != owned_service_names_.end();) {
 484     // This is a bit tricky but we should increment the iter here as
 485     // ReleaseOwnership() may remove |service_name| from the set.
 486     const std::string& service_name = *iter++;
 487     ReleaseOwnership(service_name);
 488   }
 489   if (!owned_service_names_.empty()) {
 490     LOG(ERROR) << "Failed to release all service names. # of services left: "
 491                << owned_service_names_.size();
 492   }
 493
 494   // Detach from the remote objects.
 495   for (ObjectProxyTable::iterator iter = object_proxy_table_.begin();
 496        iter != object_proxy_table_.end(); ++iter) {
 497     iter->second->Detach();
 498   }
 499
 500   // Clean up the object managers.
 501   for (ObjectManagerTable::iterator iter = object_manager_table_.begin();
 502        iter != object_manager_table_.end(); ++iter) {
 503     iter->second->CleanUp();
 504   }
 505
 506   // Release object proxies and exported objects here. We should do this
 507   // here rather than in the destructor to avoid memory leaks due to
 508   // cyclic references.
 509   object_proxy_table_.clear();
 510   exported_object_table_.clear();
 511
 512   // Private connection should be closed.
 513   if (connection_) {
 514     // Remove Disconnected watcher.
 515     ScopedDBusError error;
 516     RemoveFilterFunction(Bus::OnConnectionDisconnectedFilter, this);
 517     RemoveMatch(kDisconnectedMatchRule, error.get());
 518
 519     if (connection_type_ == PRIVATE)
 520       ClosePrivateConnection();
 521     // dbus_connection_close() won't unref.
 522     dbus_connection_unref(connection_);
 523   }
 524
 525   connection_ = NULL;
 526   shutdown_completed_ = true;
 527 }
 528
 529 void Bus::ShutdownOnDBusThreadAndBlock() {
 530   AssertOnOriginThread();
 531   DCHECK(dbus_task_runner_.get());
 532
 533   GetDBusTaskRunner()->PostTask(
 534       FROM_HERE,
 535       base::Bind(&Bus::ShutdownOnDBusThreadAndBlockInternal, this));
 536
 537   // http://crbug.com/125222
 538   base::ThreadRestrictions::ScopedAllowWait allow_wait;
 539
 540   // Wait until the shutdown is complete on the D-Bus thread.
 541   // The shutdown should not hang, but set timeout just in case.
 542   const int kTimeoutSecs = 3;
 543   const base::TimeDelta timeout(base::TimeDelta::FromSeconds(kTimeoutSecs));
 544   const bool signaled = on_shutdown_.TimedWait(timeout);
 545   LOG_IF(ERROR, !signaled) << "Failed to shutdown the bus";
 546 }
 547
 548 void Bus::RequestOwnership(const std::string& service_name,
 549                            ServiceOwnershipOptions options,
 550                            OnOwnershipCallback on_ownership_callback) {
 551   AssertOnOriginThread();
 552
 553   GetDBusTaskRunner()->PostTask(
 554       FROM_HERE,
 555       base::Bind(&Bus::RequestOwnershipInternal,
 556                  this, service_name, options, on_ownership_callback));
 557 }
 558
 559 void Bus::RequestOwnershipInternal(const std::string& service_name,
 560                                    ServiceOwnershipOptions options,
 561                                    OnOwnershipCallback on_ownership_callback) {
 562   AssertOnDBusThread();
 563
 564   bool success = Connect();
 565   if (success)
 566     success = RequestOwnershipAndBlock(service_name, options);
 567
 568   GetOriginTaskRunner()->PostTask(FROM_HERE,
 569                                   base::Bind(on_ownership_callback,
 570                                              service_name,
 571                                              success));
 572 }
 573
 574 bool Bus::RequestOwnershipAndBlock(const std::string& service_name,
 575                                    ServiceOwnershipOptions options) {
 576   DCHECK(connection_);
 577   // dbus_bus_request_name() is a blocking call.
 578   AssertOnDBusThread();
 579
 580   // Check if we already own the service name.
 581   if (owned_service_names_.find(service_name) != owned_service_names_.end()) {
 582     return true;
 583   }
 584
 585   ScopedDBusError error;
 586   const int result = dbus_bus_request_name(connection_,
 587                                            service_name.c_str(),
 588                                            options,
 589                                            error.get());
 590   if (result != DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER) {
 591     LOG(ERROR) << "Failed to get the ownership of " << service_name << ": "
 592                << (error.is_set() ? error.message() : "");
 593     return false;
 594   }
 595   owned_service_names_.insert(service_name);
 596   return true;
 597 }
 598
 599 bool Bus::ReleaseOwnership(const std::string& service_name) {
 600   DCHECK(connection_);
 601   // dbus_bus_request_name() is a blocking call.
 602   AssertOnDBusThread();
 603
 604   // Check if we already own the service name.
 605   std::set<std::string>::iterator found =
 606       owned_service_names_.find(service_name);
 607   if (found == owned_service_names_.end()) {
 608     LOG(ERROR) << service_name << " is not owned by the bus";
 609     return false;
 610   }
 611
 612   ScopedDBusError error;
 613   const int result = dbus_bus_release_name(connection_, service_name.c_str(),
 614                                            error.get());
 615   if (result == DBUS_RELEASE_NAME_REPLY_RELEASED) {
 616     owned_service_names_.erase(found);
 617     return true;
 618   } else {
 619     LOG(ERROR) << "Failed to release the ownership of " << service_name << ": "
 620                << (error.is_set() ? error.message() : "")
 621                << ", result code: " << result;
 622     return false;
 623   }
 624 }
 625
 626 bool Bus::SetUpAsyncOperations() {
 627   DCHECK(connection_);
 628   AssertOnDBusThread();
 629
 630   if (async_operations_set_up_)
 631     return true;
 632
 633   // Process all the incoming data if any, so that OnDispatchStatus() will
 634   // be called when the incoming data is ready.
 635   ProcessAllIncomingDataIfAny();
 636
 637   bool success = dbus_connection_set_watch_functions(connection_,
 638                                                      &Bus::OnAddWatchThunk,
 639                                                      &Bus::OnRemoveWatchThunk,
 640                                                      &Bus::OnToggleWatchThunk,
 641                                                      this,
 642                                                      NULL);
 643   CHECK(success) << "Unable to allocate memory";
 644
 645   success = dbus_connection_set_timeout_functions(connection_,
 646                                                   &Bus::OnAddTimeoutThunk,
 647                                                   &Bus::OnRemoveTimeoutThunk,
 648                                                   &Bus::OnToggleTimeoutThunk,
 649                                                   this,
 650                                                   NULL);
 651   CHECK(success) << "Unable to allocate memory";
 652
 653   dbus_connection_set_dispatch_status_function(
 654       connection_,
 655       &Bus::OnDispatchStatusChangedThunk,
 656       this,
 657       NULL);
 658
 659   async_operations_set_up_ = true;
 660
 661   return true;
 662 }
 663
 664 DBusMessage* Bus::SendWithReplyAndBlock(DBusMessage* request,
 665                                         int timeout_ms,
 666                                         DBusError* error) {
 667   DCHECK(connection_);
 668   AssertOnDBusThread();
 669
 670   return dbus_connection_send_with_reply_and_block(
 671       connection_, request, timeout_ms, error);
 672 }
 673
 674 void Bus::SendWithReply(DBusMessage* request,
 675                         DBusPendingCall** pending_call,
 676                         int timeout_ms) {
 677   DCHECK(connection_);
 678   AssertOnDBusThread();
 679
 680   const bool success = dbus_connection_send_with_reply(
 681       connection_, request, pending_call, timeout_ms);
 682   CHECK(success) << "Unable to allocate memory";
 683 }
 684
 685 void Bus::Send(DBusMessage* request, uint32* serial) {
 686   DCHECK(connection_);
 687   AssertOnDBusThread();
 688
 689   const bool success = dbus_connection_send(connection_, request, serial);
 690   CHECK(success) << "Unable to allocate memory";
 691 }
 692
 693 bool Bus::AddFilterFunction(DBusHandleMessageFunction filter_function,
 694                             void* user_data) {
 695   DCHECK(connection_);
 696   AssertOnDBusThread();
 697
 698   std::pair<DBusHandleMessageFunction, void*> filter_data_pair =
 699       std::make_pair(filter_function, user_data);
 700   if (filter_functions_added_.find(filter_data_pair) !=
 701       filter_functions_added_.end()) {
 702     VLOG(1) << "Filter function already exists: " << filter_function
 703             << " with associated data: " << user_data;
 704     return false;
 705   }
 706
 707   const bool success = dbus_connection_add_filter(
 708       connection_, filter_function, user_data, NULL);
 709   CHECK(success) << "Unable to allocate memory";
 710   filter_functions_added_.insert(filter_data_pair);
 711   return true;
 712 }
 713
 714 bool Bus::RemoveFilterFunction(DBusHandleMessageFunction filter_function,
 715                                void* user_data) {
 716   DCHECK(connection_);
 717   AssertOnDBusThread();
 718
 719   std::pair<DBusHandleMessageFunction, void*> filter_data_pair =
 720       std::make_pair(filter_function, user_data);
 721   if (filter_functions_added_.find(filter_data_pair) ==
 722       filter_functions_added_.end()) {
 723     VLOG(1) << "Requested to remove an unknown filter function: "
 724             << filter_function
 725             << " with associated data: " << user_data;
 726     return false;
 727   }
 728
 729   dbus_connection_remove_filter(connection_, filter_function, user_data);
 730   filter_functions_added_.erase(filter_data_pair);
 731   return true;
 732 }
 733
 734 void Bus::AddMatch(const std::string& match_rule, DBusError* error) {
 735   DCHECK(connection_);
 736   AssertOnDBusThread();
 737
 738   std::map<std::string, int>::iterator iter =
 739       match_rules_added_.find(match_rule);
 740   if (iter != match_rules_added_.end()) {
 741     // The already existing rule's counter is incremented.
 742     iter->second++;
 743
 744     VLOG(1) << "Match rule already exists: " << match_rule;
 745     return;
 746   }
 747
 748   dbus_bus_add_match(connection_, match_rule.c_str(), error);
 749   match_rules_added_[match_rule] = 1;
 750 }
 751
 752 bool Bus::RemoveMatch(const std::string& match_rule, DBusError* error) {
 753   DCHECK(connection_);
 754   AssertOnDBusThread();
 755
 756   std::map<std::string, int>::iterator iter =
 757       match_rules_added_.find(match_rule);
 758   if (iter == match_rules_added_.end()) {
 759     LOG(ERROR) << "Requested to remove an unknown match rule: " << match_rule;
 760     return false;
 761   }
 762
 763   // The rule's counter is decremented and the rule is deleted when reachs 0.
 764   iter->second--;
 765   if (iter->second == 0) {
 766     dbus_bus_remove_match(connection_, match_rule.c_str(), error);
 767     match_rules_added_.erase(match_rule);
 768   }
 769   return true;
 770 }
 771
 772 bool Bus::TryRegisterObjectPath(const ObjectPath& object_path,
 773                                 const DBusObjectPathVTable* vtable,
 774                                 void* user_data,
 775                                 DBusError* error) {
 776   DCHECK(connection_);
 777   AssertOnDBusThread();
 778
 779   if (registered_object_paths_.find(object_path) !=
 780       registered_object_paths_.end()) {
 781     LOG(ERROR) << "Object path already registered: " << object_path.value();
 782     return false;
 783   }
 784
 785   const bool success = dbus_connection_try_register_object_path(
 786       connection_,
 787       object_path.value().c_str(),
 788       vtable,
 789       user_data,
 790       error);
 791   if (success)
 792     registered_object_paths_.insert(object_path);
 793   return success;
 794 }
 795
 796 void Bus::UnregisterObjectPath(const ObjectPath& object_path) {
 797   DCHECK(connection_);
 798   AssertOnDBusThread();
 799
 800   if (registered_object_paths_.find(object_path) ==
 801       registered_object_paths_.end()) {
 802     LOG(ERROR) << "Requested to unregister an unknown object path: "
 803                << object_path.value();
 804     return;
 805   }
 806
 807   const bool success = dbus_connection_unregister_object_path(
 808       connection_,
 809       object_path.value().c_str());
 810   CHECK(success) << "Unable to allocate memory";
 811   registered_object_paths_.erase(object_path);
 812 }
 813
 814 void Bus::ShutdownOnDBusThreadAndBlockInternal() {
 815   AssertOnDBusThread();
 816
 817   ShutdownAndBlock();
 818   on_shutdown_.Signal();
 819 }
 820
 821 void Bus::ProcessAllIncomingDataIfAny() {
 822   AssertOnDBusThread();
 823
 824   // As mentioned at the class comment in .h file, connection_ can be NULL.
 825   if (!connection_)
 826     return;
 827
 828   // It is safe and necessary to call dbus_connection_get_dispatch_status even
 829   // if the connection is lost. Otherwise we will miss "Disconnected" signal.
 830   // (crbug.com/174431)
 831   if (dbus_connection_get_dispatch_status(connection_) ==
 832       DBUS_DISPATCH_DATA_REMAINS) {
 833     while (dbus_connection_dispatch(connection_) ==
 834            DBUS_DISPATCH_DATA_REMAINS) {
 835     }
 836   }
 837 }
 838
 839 base::TaskRunner* Bus::GetDBusTaskRunner() {
 840   if (dbus_task_runner_.get())
 841     return dbus_task_runner_.get();
 842   else
 843     return GetOriginTaskRunner();
 844 }
 845
 846 base::TaskRunner* Bus::GetOriginTaskRunner() {
 847   DCHECK(origin_task_runner_.get());
 848   return origin_task_runner_.get();
 849 }
 850
 851 bool Bus::HasDBusThread() {
 852   return dbus_task_runner_.get() != NULL;
 853 }
 854
 855 void Bus::AssertOnOriginThread() {
 856   DCHECK_EQ(origin_thread_id_, base::PlatformThread::CurrentId());
 857 }
 858
 859 void Bus::AssertOnDBusThread() {
 860   base::ThreadRestrictions::AssertIOAllowed();
 861
 862   if (dbus_task_runner_.get()) {
 863     DCHECK(dbus_task_runner_->RunsTasksOnCurrentThread());
 864   } else {
 865     AssertOnOriginThread();
 866   }
 867 }
 868
 869 std::string Bus::GetServiceOwnerAndBlock(const std::string& service_name,
 870                                          GetServiceOwnerOption options) {
 871   AssertOnDBusThread();
 872
 873   MethodCall get_name_owner_call("org.freedesktop.DBus", "GetNameOwner");
 874   MessageWriter writer(&get_name_owner_call);
 875   writer.AppendString(service_name);
 876   VLOG(1) << "Method call: " << get_name_owner_call.ToString();
 877
 878   const ObjectPath obj_path("/org/freedesktop/DBus");
 879   if (!get_name_owner_call.SetDestination("org.freedesktop.DBus") ||
 880       !get_name_owner_call.SetPath(obj_path)) {
 881     if (options == REPORT_ERRORS)
 882       LOG(ERROR) << "Failed to get name owner.";
 883     return "";
 884   }
 885
 886   ScopedDBusError error;
 887   DBusMessage* response_message =
 888       SendWithReplyAndBlock(get_name_owner_call.raw_message(),
 889                             ObjectProxy::TIMEOUT_USE_DEFAULT,
 890                             error.get());
 891   if (!response_message) {
 892     if (options == REPORT_ERRORS) {
 893       LOG(ERROR) << "Failed to get name owner. Got " << error.name() << ": "
 894                  << error.message();
 895     }
 896     return "";
 897   }
 898
 899   scoped_ptr<Response> response(Response::FromRawMessage(response_message));
 900   MessageReader reader(response.get());
 901
 902   std::string service_owner;
 903   if (!reader.PopString(&service_owner))
 904     service_owner.clear();
 905   return service_owner;
 906 }
 907
 908 void Bus::GetServiceOwner(const std::string& service_name,
 909                           const GetServiceOwnerCallback& callback) {
 910   AssertOnOriginThread();
 911
 912   GetDBusTaskRunner()->PostTask(
 913       FROM_HERE,
 914       base::Bind(&Bus::GetServiceOwnerInternal, this, service_name, callback));
 915 }
 916
 917 void Bus::GetServiceOwnerInternal(const std::string& service_name,
 918                                   const GetServiceOwnerCallback& callback) {
 919   AssertOnDBusThread();
 920
 921   std::string service_owner;
 922   if (Connect())
 923     service_owner = GetServiceOwnerAndBlock(service_name, SUPPRESS_ERRORS);
 924   GetOriginTaskRunner()->PostTask(FROM_HERE,
 925                                   base::Bind(callback, service_owner));
 926 }
 927
 928 void Bus::ListenForServiceOwnerChange(
 929     const std::string& service_name,
 930     const GetServiceOwnerCallback& callback) {
 931   AssertOnOriginThread();
 932   DCHECK(!service_name.empty());
 933   DCHECK(!callback.is_null());
 934
 935   GetDBusTaskRunner()->PostTask(
 936       FROM_HERE,
 937       base::Bind(&Bus::ListenForServiceOwnerChangeInternal,
 938                  this, service_name, callback));
 939 }
 940
 941 void Bus::ListenForServiceOwnerChangeInternal(
 942     const std::string& service_name,
 943     const GetServiceOwnerCallback& callback) {
 944   AssertOnDBusThread();
 945   DCHECK(!service_name.empty());
 946   DCHECK(!callback.is_null());
 947
 948   if (!Connect() || !SetUpAsyncOperations())
 949     return;
 950
 951   if (service_owner_changed_listener_map_.empty()) {
 952     bool filter_added =
 953         AddFilterFunction(Bus::OnServiceOwnerChangedFilter, this);
 954     DCHECK(filter_added);
 955   }
 956
 957   ServiceOwnerChangedListenerMap::iterator it =
 958       service_owner_changed_listener_map_.find(service_name);
 959   if (it == service_owner_changed_listener_map_.end()) {
 960     // Add a match rule for the new service name.
 961     const std::string name_owner_changed_match_rule =
 962         base::StringPrintf(kServiceNameOwnerChangeMatchRule,
 963                            service_name.c_str());
 964     ScopedDBusError error;
 965     AddMatch(name_owner_changed_match_rule, error.get());
 966     if (error.is_set()) {
 967       LOG(ERROR) << "Failed to add match rule for " << service_name
 968                  << ". Got " << error.name() << ": " << error.message();
 969       return;
 970     }
 971
 972     service_owner_changed_listener_map_[service_name].push_back(callback);
 973     return;
 974   }
 975
 976   // Check if the callback has already been added.
 977   std::vector<GetServiceOwnerCallback>& callbacks = it->second;
 978   for (size_t i = 0; i < callbacks.size(); ++i) {
 979     if (callbacks[i].Equals(callback))
 980       return;
 981   }
 982   callbacks.push_back(callback);
 983 }
 984
 985 void Bus::UnlistenForServiceOwnerChange(
 986     const std::string& service_name,
 987     const GetServiceOwnerCallback& callback) {
 988   AssertOnOriginThread();
 989   DCHECK(!service_name.empty());
 990   DCHECK(!callback.is_null());
 991
 992   GetDBusTaskRunner()->PostTask(
 993       FROM_HERE,
 994       base::Bind(&Bus::UnlistenForServiceOwnerChangeInternal,
 995                  this, service_name, callback));
 996 }
 997
 998 void Bus::UnlistenForServiceOwnerChangeInternal(
 999     const std::string& service_name,
1000     const GetServiceOwnerCallback& callback) {
1001   AssertOnDBusThread();
1002   DCHECK(!service_name.empty());
1003   DCHECK(!callback.is_null());
1004
1005   ServiceOwnerChangedListenerMap::iterator it =
1006       service_owner_changed_listener_map_.find(service_name);
1007   if (it == service_owner_changed_listener_map_.end())
1008     return;
1009
1010   std::vector<GetServiceOwnerCallback>& callbacks = it->second;
1011   for (size_t i = 0; i < callbacks.size(); ++i) {
1012     if (callbacks[i].Equals(callback)) {
1013       callbacks.erase(callbacks.begin() + i);
1014       break;  // There can be only one.
1015     }
1016   }
1017   if (!callbacks.empty())
1018     return;
1019
1020   // Last callback for |service_name| has been removed, remove match rule.
1021   const std::string name_owner_changed_match_rule =
1022       base::StringPrintf(kServiceNameOwnerChangeMatchRule,
1023                          service_name.c_str());
1024   ScopedDBusError error;
1025   RemoveMatch(name_owner_changed_match_rule, error.get());
1026   // And remove |service_owner_changed_listener_map_| entry.
1027   service_owner_changed_listener_map_.erase(it);
1028
1029   if (service_owner_changed_listener_map_.empty()) {
1030     bool filter_removed =
1031         RemoveFilterFunction(Bus::OnServiceOwnerChangedFilter, this);
1032     DCHECK(filter_removed);
1033   }
1034 }
1035
1036 dbus_bool_t Bus::OnAddWatch(DBusWatch* raw_watch) {
1037   AssertOnDBusThread();
1038
1039   // watch will be deleted when raw_watch is removed in OnRemoveWatch().
1040   Watch* watch = new Watch(raw_watch);
1041   if (watch->IsReadyToBeWatched()) {
1042     watch->StartWatching();
1043   }
1044   ++num_pending_watches_;
1045   return true;
1046 }
1047
1048 void Bus::OnRemoveWatch(DBusWatch* raw_watch) {
1049   AssertOnDBusThread();
1050
1051   Watch* watch = static_cast<Watch*>(dbus_watch_get_data(raw_watch));
1052   delete watch;
1053   --num_pending_watches_;
1054 }
1055
1056 void Bus::OnToggleWatch(DBusWatch* raw_watch) {
1057   AssertOnDBusThread();
1058
1059   Watch* watch = static_cast<Watch*>(dbus_watch_get_data(raw_watch));
1060   if (watch->IsReadyToBeWatched()) {
1061     watch->StartWatching();
1062   } else {
1063     // It's safe to call this if StartWatching() wasn't called, per
1064     // message_pump_libevent.h.
1065     watch->StopWatching();
1066   }
1067 }
1068
1069 dbus_bool_t Bus::OnAddTimeout(DBusTimeout* raw_timeout) {
1070   AssertOnDBusThread();
1071
1072   // timeout will be deleted when raw_timeout is removed in
1073   // OnRemoveTimeoutThunk().
1074   Timeout* timeout = new Timeout(raw_timeout);
1075   if (timeout->IsReadyToBeMonitored()) {
1076     timeout->StartMonitoring(this);
1077   }
1078   ++num_pending_timeouts_;
1079   return true;
1080 }
1081
1082 void Bus::OnRemoveTimeout(DBusTimeout* raw_timeout) {
1083   AssertOnDBusThread();
1084
1085   Timeout* timeout = static_cast<Timeout*>(dbus_timeout_get_data(raw_timeout));
1086   timeout->Complete();
1087   --num_pending_timeouts_;
1088 }
1089
1090 void Bus::OnToggleTimeout(DBusTimeout* raw_timeout) {
1091   AssertOnDBusThread();
1092
1093   Timeout* timeout = static_cast<Timeout*>(dbus_timeout_get_data(raw_timeout));
1094   if (timeout->IsReadyToBeMonitored()) {
1095     timeout->StartMonitoring(this);
1096   } else {
1097     timeout->StopMonitoring();
1098   }
1099 }
1100
1101 void Bus::OnDispatchStatusChanged(DBusConnection* connection,
1102                                   DBusDispatchStatus status) {
1103   DCHECK_EQ(connection, connection_);
1104   AssertOnDBusThread();
1105
1106   // We cannot call ProcessAllIncomingDataIfAny() here, as calling
1107   // dbus_connection_dispatch() inside DBusDispatchStatusFunction is
1108   // prohibited by the D-Bus library. Hence, we post a task here instead.
1109   // See comments for dbus_connection_set_dispatch_status_function().
1110   GetDBusTaskRunner()->PostTask(FROM_HERE,
1111                                 base::Bind(&Bus::ProcessAllIncomingDataIfAny,
1112                                            this));
1113 }
1114
1115 void Bus::OnConnectionDisconnected(DBusConnection* connection) {
1116   AssertOnDBusThread();
1117
1118   if (!on_disconnected_closure_.is_null())
1119     GetOriginTaskRunner()->PostTask(FROM_HERE, on_disconnected_closure_);
1120
1121   if (!connection)
1122     return;
1123   DCHECK(!dbus_connection_get_is_connected(connection));
1124
1125   ShutdownAndBlock();
1126 }
1127
1128 void Bus::OnServiceOwnerChanged(DBusMessage* message) {
1129   DCHECK(message);
1130   AssertOnDBusThread();
1131
1132   // |message| will be unrefed on exit of the function. Increment the
1133   // reference so we can use it in Signal::FromRawMessage() below.
1134   dbus_message_ref(message);
1135   scoped_ptr<Signal> signal(Signal::FromRawMessage(message));
1136
1137   // Confirm the validity of the NameOwnerChanged signal.
1138   if (signal->GetMember() != kNameOwnerChangedSignal ||
1139       signal->GetInterface() != DBUS_INTERFACE_DBUS ||
1140       signal->GetSender() != DBUS_SERVICE_DBUS) {
1141     return;
1142   }
1143
1144   MessageReader reader(signal.get());
1145   std::string service_name;
1146   std::string old_owner;
1147   std::string new_owner;
1148   if (!reader.PopString(&service_name) ||
1149       !reader.PopString(&old_owner) ||
1150       !reader.PopString(&new_owner)) {
1151     return;
1152   }
1153
1154   ServiceOwnerChangedListenerMap::const_iterator it =
1155       service_owner_changed_listener_map_.find(service_name);
1156   if (it == service_owner_changed_listener_map_.end())
1157     return;
1158
1159   const std::vector<GetServiceOwnerCallback>& callbacks = it->second;
1160   for (size_t i = 0; i < callbacks.size(); ++i) {
1161     GetOriginTaskRunner()->PostTask(FROM_HERE,
1162                                     base::Bind(callbacks[i], new_owner));
1163   }
1164 }
1165
1166 // static
1167 dbus_bool_t Bus::OnAddWatchThunk(DBusWatch* raw_watch, void* data) {
1168   Bus* self = static_cast<Bus*>(data);
1169   return self->OnAddWatch(raw_watch);
1170 }
1171
1172 // static
1173 void Bus::OnRemoveWatchThunk(DBusWatch* raw_watch, void* data) {
1174   Bus* self = static_cast<Bus*>(data);
1175   self->OnRemoveWatch(raw_watch);
1176 }
1177
1178 // static
1179 void Bus::OnToggleWatchThunk(DBusWatch* raw_watch, void* data) {
1180   Bus* self = static_cast<Bus*>(data);
1181   self->OnToggleWatch(raw_watch);
1182 }
1183
1184 // static
1185 dbus_bool_t Bus::OnAddTimeoutThunk(DBusTimeout* raw_timeout, void* data) {
1186   Bus* self = static_cast<Bus*>(data);
1187   return self->OnAddTimeout(raw_timeout);
1188 }
1189
1190 // static
1191 void Bus::OnRemoveTimeoutThunk(DBusTimeout* raw_timeout, void* data) {
1192   Bus* self = static_cast<Bus*>(data);
1193   self->OnRemoveTimeout(raw_timeout);
1194 }
1195
1196 // static
1197 void Bus::OnToggleTimeoutThunk(DBusTimeout* raw_timeout, void* data) {
1198   Bus* self = static_cast<Bus*>(data);
1199   self->OnToggleTimeout(raw_timeout);
1200 }
1201
1202 // static
1203 void Bus::OnDispatchStatusChangedThunk(DBusConnection* connection,
1204                                        DBusDispatchStatus status,
1205                                        void* data) {
1206   Bus* self = static_cast<Bus*>(data);
1207   self->OnDispatchStatusChanged(connection, status);
1208 }
1209
1210 // static
1211 DBusHandlerResult Bus::OnConnectionDisconnectedFilter(
1212     DBusConnection* connection,
1213     DBusMessage* message,
1214     void* data) {
1215   if (dbus_message_is_signal(message,
1216                              DBUS_INTERFACE_LOCAL,
1217                              kDisconnectedSignal)) {
1218     Bus* self = static_cast<Bus*>(data);
1219     self->OnConnectionDisconnected(connection);
1220     return DBUS_HANDLER_RESULT_HANDLED;
1221   }
1222   return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
1223 }
1224
1225 // static
1226 DBusHandlerResult Bus::OnServiceOwnerChangedFilter(
1227     DBusConnection* connection,
1228     DBusMessage* message,
1229     void* data) {
1230   if (dbus_message_is_signal(message,
1231                              DBUS_INTERFACE_DBUS,
1232                              kNameOwnerChangedSignal)) {
1233     Bus* self = static_cast<Bus*>(data);
1234     self->OnServiceOwnerChanged(message);
1235   }
1236   // Always return unhandled to let others, e.g. ObjectProxies, handle the same
1237   // signal.
1238   return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
1239 }
1240
1241 }  // namespace dbus