// Copyright (c) 2012 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. #include "dbus/bus.h" #include "base/bind.h" #include "base/logging.h" #include "base/message_loop/message_loop.h" #include "base/metrics/histogram.h" #include "base/strings/string_piece.h" #include "base/strings/stringprintf.h" #include "base/task_runner_util.h" #include "base/threading/thread.h" #include "base/threading/thread_restrictions.h" #include "dbus/dbus_statistics.h" #include "dbus/message.h" #include "dbus/object_path.h" #include "dbus/object_proxy.h" #include "dbus/scoped_dbus_error.h" #include "dbus/util.h" namespace dbus { namespace { const char kErrorServiceUnknown[] = "org.freedesktop.DBus.Error.ServiceUnknown"; const char kErrorObjectUnknown[] = "org.freedesktop.DBus.Error.UnknownObject"; // Used for success ratio histograms. 1 for success, 0 for failure. const int kSuccessRatioHistogramMaxValue = 2; // The path of D-Bus Object sending NameOwnerChanged signal. const char kDBusSystemObjectPath[] = "/org/freedesktop/DBus"; // The D-Bus Object interface. const char kDBusSystemObjectInterface[] = "org.freedesktop.DBus"; // The D-Bus Object address. const char kDBusSystemObjectAddress[] = "org.freedesktop.DBus"; // The NameOwnerChanged member in |kDBusSystemObjectInterface|. const char kNameOwnerChangedMember[] = "NameOwnerChanged"; // An empty function used for ObjectProxy::EmptyResponseCallback(). void EmptyResponseCallbackBody(Response* /*response*/) { } } // namespace ObjectProxy::ObjectProxy(Bus* bus, const std::string& service_name, const ObjectPath& object_path, int options) : bus_(bus), service_name_(service_name), object_path_(object_path), filter_added_(false), ignore_service_unknown_errors_( options & IGNORE_SERVICE_UNKNOWN_ERRORS) { } ObjectProxy::~ObjectProxy() { } // Originally we tried to make |method_call| a const reference, but we // gave up as dbus_connection_send_with_reply_and_block() takes a // non-const pointer of DBusMessage as the second parameter. scoped_ptr<Response> ObjectProxy::CallMethodAndBlockWithErrorDetails( MethodCall* method_call, int timeout_ms, ScopedDBusError* error) { bus_->AssertOnDBusThread(); if (!bus_->Connect() || !method_call->SetDestination(service_name_) || !method_call->SetPath(object_path_)) return scoped_ptr<Response>(); DBusMessage* request_message = method_call->raw_message(); // Send the message synchronously. const base::TimeTicks start_time = base::TimeTicks::Now(); DBusMessage* response_message = bus_->SendWithReplyAndBlock(request_message, timeout_ms, error->get()); // Record if the method call is successful, or not. 1 if successful. UMA_HISTOGRAM_ENUMERATION("DBus.SyncMethodCallSuccess", response_message ? 1 : 0, kSuccessRatioHistogramMaxValue); statistics::AddBlockingSentMethodCall(service_name_, method_call->GetInterface(), method_call->GetMember()); if (!response_message) { LogMethodCallFailure(method_call->GetInterface(), method_call->GetMember(), error->is_set() ? error->name() : "unknown error type", error->is_set() ? error->message() : ""); return scoped_ptr<Response>(); } // Record time spent for the method call. Don't include failures. UMA_HISTOGRAM_TIMES("DBus.SyncMethodCallTime", base::TimeTicks::Now() - start_time); return Response::FromRawMessage(response_message); } scoped_ptr<Response> ObjectProxy::CallMethodAndBlock(MethodCall* method_call, int timeout_ms) { ScopedDBusError error; return CallMethodAndBlockWithErrorDetails(method_call, timeout_ms, &error); } void ObjectProxy::CallMethod(MethodCall* method_call, int timeout_ms, ResponseCallback callback) { CallMethodWithErrorCallback(method_call, timeout_ms, callback, base::Bind(&ObjectProxy::OnCallMethodError, this, method_call->GetInterface(), method_call->GetMember(), callback)); } void ObjectProxy::CallMethodWithErrorCallback(MethodCall* method_call, int timeout_ms, ResponseCallback callback, ErrorCallback error_callback) { bus_->AssertOnOriginThread(); const base::TimeTicks start_time = base::TimeTicks::Now(); if (!method_call->SetDestination(service_name_) || !method_call->SetPath(object_path_)) { // In case of a failure, run the error callback with NULL. DBusMessage* response_message = NULL; base::Closure task = base::Bind(&ObjectProxy::RunResponseCallback, this, callback, error_callback, start_time, response_message); bus_->GetOriginTaskRunner()->PostTask(FROM_HERE, task); return; } // Increment the reference count so we can safely reference the // underlying request message until the method call is complete. This // will be unref'ed in StartAsyncMethodCall(). DBusMessage* request_message = method_call->raw_message(); dbus_message_ref(request_message); base::Closure task = base::Bind(&ObjectProxy::StartAsyncMethodCall, this, timeout_ms, request_message, callback, error_callback, start_time); statistics::AddSentMethodCall(service_name_, method_call->GetInterface(), method_call->GetMember()); // Wait for the response in the D-Bus thread. bus_->GetDBusTaskRunner()->PostTask(FROM_HERE, task); } void ObjectProxy::ConnectToSignal(const std::string& interface_name, const std::string& signal_name, SignalCallback signal_callback, OnConnectedCallback on_connected_callback) { bus_->AssertOnOriginThread(); base::PostTaskAndReplyWithResult( bus_->GetDBusTaskRunner(), FROM_HERE, base::Bind(&ObjectProxy::ConnectToSignalInternal, this, interface_name, signal_name, signal_callback), base::Bind(on_connected_callback, interface_name, signal_name)); } void ObjectProxy::SetNameOwnerChangedCallback( NameOwnerChangedCallback callback) { bus_->AssertOnOriginThread(); name_owner_changed_callback_ = callback; } void ObjectProxy::WaitForServiceToBeAvailable( WaitForServiceToBeAvailableCallback callback) { bus_->AssertOnOriginThread(); wait_for_service_to_be_available_callbacks_.push_back(callback); bus_->GetDBusTaskRunner()->PostTask( FROM_HERE, base::Bind(&ObjectProxy::WaitForServiceToBeAvailableInternal, this)); } void ObjectProxy::Detach() { bus_->AssertOnDBusThread(); if (filter_added_) { if (!bus_->RemoveFilterFunction(&ObjectProxy::HandleMessageThunk, this)) { LOG(ERROR) << "Failed to remove filter function"; } } for (std::set<std::string>::iterator iter = match_rules_.begin(); iter != match_rules_.end(); ++iter) { ScopedDBusError error; bus_->RemoveMatch(*iter, error.get()); if (error.is_set()) { // There is nothing we can do to recover, so just print the error. LOG(ERROR) << "Failed to remove match rule: " << *iter; } } match_rules_.clear(); } // static ObjectProxy::ResponseCallback ObjectProxy::EmptyResponseCallback() { return base::Bind(&EmptyResponseCallbackBody); } ObjectProxy::OnPendingCallIsCompleteData::OnPendingCallIsCompleteData( ObjectProxy* in_object_proxy, ResponseCallback in_response_callback, ErrorCallback in_error_callback, base::TimeTicks in_start_time) : object_proxy(in_object_proxy), response_callback(in_response_callback), error_callback(in_error_callback), start_time(in_start_time) { } ObjectProxy::OnPendingCallIsCompleteData::~OnPendingCallIsCompleteData() { } void ObjectProxy::StartAsyncMethodCall(int timeout_ms, DBusMessage* request_message, ResponseCallback response_callback, ErrorCallback error_callback, base::TimeTicks start_time) { bus_->AssertOnDBusThread(); if (!bus_->Connect() || !bus_->SetUpAsyncOperations()) { // In case of a failure, run the error callback with NULL. DBusMessage* response_message = NULL; base::Closure task = base::Bind(&ObjectProxy::RunResponseCallback, this, response_callback, error_callback, start_time, response_message); bus_->GetOriginTaskRunner()->PostTask(FROM_HERE, task); dbus_message_unref(request_message); return; } DBusPendingCall* pending_call = NULL; bus_->SendWithReply(request_message, &pending_call, timeout_ms); // Prepare the data we'll be passing to OnPendingCallIsCompleteThunk(). // The data will be deleted in OnPendingCallIsCompleteThunk(). OnPendingCallIsCompleteData* data = new OnPendingCallIsCompleteData(this, response_callback, error_callback, start_time); // This returns false only when unable to allocate memory. const bool success = dbus_pending_call_set_notify( pending_call, &ObjectProxy::OnPendingCallIsCompleteThunk, data, NULL); CHECK(success) << "Unable to allocate memory"; dbus_pending_call_unref(pending_call); // It's now safe to unref the request message. dbus_message_unref(request_message); } void ObjectProxy::OnPendingCallIsComplete(DBusPendingCall* pending_call, ResponseCallback response_callback, ErrorCallback error_callback, base::TimeTicks start_time) { bus_->AssertOnDBusThread(); DBusMessage* response_message = dbus_pending_call_steal_reply(pending_call); base::Closure task = base::Bind(&ObjectProxy::RunResponseCallback, this, response_callback, error_callback, start_time, response_message); bus_->GetOriginTaskRunner()->PostTask(FROM_HERE, task); } void ObjectProxy::RunResponseCallback(ResponseCallback response_callback, ErrorCallback error_callback, base::TimeTicks start_time, DBusMessage* response_message) { bus_->AssertOnOriginThread(); bool method_call_successful = false; if (!response_message) { // The response is not received. error_callback.Run(NULL); } else if (dbus_message_get_type(response_message) == DBUS_MESSAGE_TYPE_ERROR) { // This will take |response_message| and release (unref) it. scoped_ptr<ErrorResponse> error_response( ErrorResponse::FromRawMessage(response_message)); error_callback.Run(error_response.get()); // Delete the message on the D-Bus thread. See below for why. bus_->GetDBusTaskRunner()->PostTask( FROM_HERE, base::Bind(&base::DeletePointer<ErrorResponse>, error_response.release())); } else { // This will take |response_message| and release (unref) it. scoped_ptr<Response> response(Response::FromRawMessage(response_message)); // The response is successfully received. response_callback.Run(response.get()); // The message should be deleted on the D-Bus thread for a complicated // reason: // // libdbus keeps track of the number of bytes in the incoming message // queue to ensure that the data size in the queue is manageable. The // bookkeeping is partly done via dbus_message_unref(), and immediately // asks the client code (Chrome) to stop monitoring the underlying // socket, if the number of bytes exceeds a certian number, which is set // to 63MB, per dbus-transport.cc: // // /* Try to default to something that won't totally hose the system, // * but doesn't impose too much of a limitation. // */ // transport->max_live_messages_size = _DBUS_ONE_MEGABYTE * 63; // // The monitoring of the socket is done on the D-Bus thread (see Watch // class in bus.cc), hence we should stop the monitoring from D-Bus // thread, not from the current thread here, which is likely UI thread. bus_->GetDBusTaskRunner()->PostTask( FROM_HERE, base::Bind(&base::DeletePointer<Response>, response.release())); method_call_successful = true; // Record time spent for the method call. Don't include failures. UMA_HISTOGRAM_TIMES("DBus.AsyncMethodCallTime", base::TimeTicks::Now() - start_time); } // Record if the method call is successful, or not. 1 if successful. UMA_HISTOGRAM_ENUMERATION("DBus.AsyncMethodCallSuccess", method_call_successful, kSuccessRatioHistogramMaxValue); } void ObjectProxy::OnPendingCallIsCompleteThunk(DBusPendingCall* pending_call, void* user_data) { OnPendingCallIsCompleteData* data = reinterpret_cast<OnPendingCallIsCompleteData*>(user_data); ObjectProxy* self = data->object_proxy; self->OnPendingCallIsComplete(pending_call, data->response_callback, data->error_callback, data->start_time); delete data; } bool ObjectProxy::ConnectToNameOwnerChangedSignal() { bus_->AssertOnDBusThread(); if (!bus_->Connect() || !bus_->SetUpAsyncOperations()) return false; // We should add the filter only once. Otherwise, HandleMessage() will // be called more than once. if (!filter_added_) { if (bus_->AddFilterFunction(&ObjectProxy::HandleMessageThunk, this)) { filter_added_ = true; } else { LOG(ERROR) << "Failed to add filter function"; } } // Add a match_rule listening NameOwnerChanged for the well-known name // |service_name_|. const std::string name_owner_changed_match_rule = base::StringPrintf( "type='signal',interface='org.freedesktop.DBus'," "member='NameOwnerChanged',path='/org/freedesktop/DBus'," "sender='org.freedesktop.DBus',arg0='%s'", service_name_.c_str()); const bool success = AddMatchRuleWithoutCallback(name_owner_changed_match_rule, "org.freedesktop.DBus.NameOwnerChanged"); // Try getting the current name owner. It's not guaranteed that we can get // the name owner at this moment, as the service may not yet be started. If // that's the case, we'll get the name owner via NameOwnerChanged signal, // as soon as the service is started. UpdateNameOwnerAndBlock(); return success; } bool ObjectProxy::ConnectToSignalInternal(const std::string& interface_name, const std::string& signal_name, SignalCallback signal_callback) { bus_->AssertOnDBusThread(); if (!ConnectToNameOwnerChangedSignal()) return false; const std::string absolute_signal_name = GetAbsoluteMemberName(interface_name, signal_name); // Add a match rule so the signal goes through HandleMessage(). const std::string match_rule = base::StringPrintf("type='signal', interface='%s', path='%s'", interface_name.c_str(), object_path_.value().c_str()); return AddMatchRuleWithCallback(match_rule, absolute_signal_name, signal_callback); } void ObjectProxy::WaitForServiceToBeAvailableInternal() { bus_->AssertOnDBusThread(); if (!ConnectToNameOwnerChangedSignal()) { // Failed to connect to the signal. const bool service_is_ready = false; bus_->GetOriginTaskRunner()->PostTask( FROM_HERE, base::Bind(&ObjectProxy::RunWaitForServiceToBeAvailableCallbacks, this, service_is_ready)); return; } const bool service_is_available = !service_name_owner_.empty(); if (service_is_available) { // Service is already available. bus_->GetOriginTaskRunner()->PostTask( FROM_HERE, base::Bind(&ObjectProxy::RunWaitForServiceToBeAvailableCallbacks, this, service_is_available)); return; } } DBusHandlerResult ObjectProxy::HandleMessage( DBusConnection* connection, DBusMessage* raw_message) { bus_->AssertOnDBusThread(); if (dbus_message_get_type(raw_message) != DBUS_MESSAGE_TYPE_SIGNAL) return DBUS_HANDLER_RESULT_NOT_YET_HANDLED; // raw_message will be unrefed on exit of the function. Increment the // reference so we can use it in Signal. dbus_message_ref(raw_message); scoped_ptr<Signal> signal( Signal::FromRawMessage(raw_message)); // Verify the signal comes from the object we're proxying for, this is // our last chance to return DBUS_HANDLER_RESULT_NOT_YET_HANDLED and // allow other object proxies to handle instead. const ObjectPath path = signal->GetPath(); if (path != object_path_) { if (path.value() == kDBusSystemObjectPath && signal->GetMember() == kNameOwnerChangedMember) { // Handle NameOwnerChanged separately return HandleNameOwnerChanged(signal.Pass()); } return DBUS_HANDLER_RESULT_NOT_YET_HANDLED; } const std::string interface = signal->GetInterface(); const std::string member = signal->GetMember(); statistics::AddReceivedSignal(service_name_, interface, member); // Check if we know about the signal. const std::string absolute_signal_name = GetAbsoluteMemberName( interface, member); MethodTable::const_iterator iter = method_table_.find(absolute_signal_name); if (iter == method_table_.end()) { // Don't know about the signal. return DBUS_HANDLER_RESULT_NOT_YET_HANDLED; } VLOG(1) << "Signal received: " << signal->ToString(); std::string sender = signal->GetSender(); if (service_name_owner_ != sender) { LOG(ERROR) << "Rejecting a message from a wrong sender."; UMA_HISTOGRAM_COUNTS("DBus.RejectedSignalCount", 1); return DBUS_HANDLER_RESULT_NOT_YET_HANDLED; } const base::TimeTicks start_time = base::TimeTicks::Now(); if (bus_->HasDBusThread()) { // Post a task to run the method in the origin thread. // Transfer the ownership of |signal| to RunMethod(). // |released_signal| will be deleted in RunMethod(). Signal* released_signal = signal.release(); bus_->GetOriginTaskRunner()->PostTask(FROM_HERE, base::Bind(&ObjectProxy::RunMethod, this, start_time, iter->second, released_signal)); } else { const base::TimeTicks start_time = base::TimeTicks::Now(); // If the D-Bus thread is not used, just call the callback on the // current thread. Transfer the ownership of |signal| to RunMethod(). Signal* released_signal = signal.release(); RunMethod(start_time, iter->second, released_signal); } // We don't return DBUS_HANDLER_RESULT_HANDLED for signals because other // objects may be interested in them. (e.g. Signals from org.freedesktop.DBus) return DBUS_HANDLER_RESULT_NOT_YET_HANDLED; } void ObjectProxy::RunMethod(base::TimeTicks start_time, std::vector<SignalCallback> signal_callbacks, Signal* signal) { bus_->AssertOnOriginThread(); for (std::vector<SignalCallback>::iterator iter = signal_callbacks.begin(); iter != signal_callbacks.end(); ++iter) iter->Run(signal); // Delete the message on the D-Bus thread. See comments in // RunResponseCallback(). bus_->GetDBusTaskRunner()->PostTask( FROM_HERE, base::Bind(&base::DeletePointer<Signal>, signal)); // Record time spent for handling the signal. UMA_HISTOGRAM_TIMES("DBus.SignalHandleTime", base::TimeTicks::Now() - start_time); } DBusHandlerResult ObjectProxy::HandleMessageThunk( DBusConnection* connection, DBusMessage* raw_message, void* user_data) { ObjectProxy* self = reinterpret_cast<ObjectProxy*>(user_data); return self->HandleMessage(connection, raw_message); } void ObjectProxy::LogMethodCallFailure( const base::StringPiece& interface_name, const base::StringPiece& method_name, const base::StringPiece& error_name, const base::StringPiece& error_message) const { if (ignore_service_unknown_errors_ && (error_name == kErrorServiceUnknown || error_name == kErrorObjectUnknown)) return; logging::LogSeverity severity = logging::LOG_ERROR; // "UnknownObject" indicates that an object or service is no longer available, // e.g. a Shill network service has gone out of range. Treat these as warnings // not errors. if (error_name == kErrorObjectUnknown) severity = logging::LOG_WARNING; std::ostringstream msg; msg << "Failed to call method: " << interface_name << "." << method_name << ": object_path= " << object_path_.value() << ": " << error_name << ": " << error_message; logging::LogAtLevel(severity, msg.str()); } void ObjectProxy::OnCallMethodError(const std::string& interface_name, const std::string& method_name, ResponseCallback response_callback, ErrorResponse* error_response) { if (error_response) { // Error message may contain the error message as string. MessageReader reader(error_response); std::string error_message; reader.PopString(&error_message); LogMethodCallFailure(interface_name, method_name, error_response->GetErrorName(), error_message); } response_callback.Run(NULL); } bool ObjectProxy::AddMatchRuleWithCallback( const std::string& match_rule, const std::string& absolute_signal_name, SignalCallback signal_callback) { DCHECK(!match_rule.empty()); DCHECK(!absolute_signal_name.empty()); bus_->AssertOnDBusThread(); if (match_rules_.find(match_rule) == match_rules_.end()) { ScopedDBusError error; bus_->AddMatch(match_rule, error.get()); if (error.is_set()) { LOG(ERROR) << "Failed to add match rule \"" << match_rule << "\". Got " << error.name() << ": " << error.message(); return false; } else { // Store the match rule, so that we can remove this in Detach(). match_rules_.insert(match_rule); // Add the signal callback to the method table. method_table_[absolute_signal_name].push_back(signal_callback); return true; } } else { // We already have the match rule. method_table_[absolute_signal_name].push_back(signal_callback); return true; } } bool ObjectProxy::AddMatchRuleWithoutCallback( const std::string& match_rule, const std::string& absolute_signal_name) { DCHECK(!match_rule.empty()); DCHECK(!absolute_signal_name.empty()); bus_->AssertOnDBusThread(); if (match_rules_.find(match_rule) != match_rules_.end()) return true; ScopedDBusError error; bus_->AddMatch(match_rule, error.get()); if (error.is_set()) { LOG(ERROR) << "Failed to add match rule \"" << match_rule << "\". Got " << error.name() << ": " << error.message(); return false; } // Store the match rule, so that we can remove this in Detach(). match_rules_.insert(match_rule); return true; } void ObjectProxy::UpdateNameOwnerAndBlock() { bus_->AssertOnDBusThread(); // Errors should be suppressed here, as the service may not be yet running // when connecting to signals of the service, which is just fine. // The ObjectProxy will be notified when the service is launched via // NameOwnerChanged signal. See also comments in ConnectToSignalInternal(). service_name_owner_ = bus_->GetServiceOwnerAndBlock(service_name_, Bus::SUPPRESS_ERRORS); } DBusHandlerResult ObjectProxy::HandleNameOwnerChanged( scoped_ptr<Signal> signal) { DCHECK(signal); bus_->AssertOnDBusThread(); // Confirm the validity of the NameOwnerChanged signal. if (signal->GetMember() == kNameOwnerChangedMember && signal->GetInterface() == kDBusSystemObjectInterface && signal->GetSender() == kDBusSystemObjectAddress) { MessageReader reader(signal.get()); std::string name, old_owner, new_owner; if (reader.PopString(&name) && reader.PopString(&old_owner) && reader.PopString(&new_owner) && name == service_name_) { service_name_owner_ = new_owner; bus_->GetOriginTaskRunner()->PostTask( FROM_HERE, base::Bind(&ObjectProxy::RunNameOwnerChangedCallback, this, old_owner, new_owner)); const bool service_is_available = !service_name_owner_.empty(); if (service_is_available) { bus_->GetOriginTaskRunner()->PostTask( FROM_HERE, base::Bind(&ObjectProxy::RunWaitForServiceToBeAvailableCallbacks, this, service_is_available)); } } } // Always return unhandled to let other object proxies handle the same // signal. return DBUS_HANDLER_RESULT_NOT_YET_HANDLED; } void ObjectProxy::RunNameOwnerChangedCallback(const std::string& old_owner, const std::string& new_owner) { bus_->AssertOnOriginThread(); if (!name_owner_changed_callback_.is_null()) name_owner_changed_callback_.Run(old_owner, new_owner); } void ObjectProxy::RunWaitForServiceToBeAvailableCallbacks( bool service_is_available) { bus_->AssertOnOriginThread(); std::vector<WaitForServiceToBeAvailableCallback> callbacks; callbacks.swap(wait_for_service_to_be_available_callbacks_); for (size_t i = 0; i < callbacks.size(); ++i) callbacks[i].Run(service_is_available); } } // namespace dbus