chromeos/dbus/session_manager_client.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 "chromeos/dbus/session_manager_client.h"
   6
   7 #include <sys/socket.h>
   8
   9 #include "base/bind.h"
  10 #include "base/callback.h"
  11 #include "base/files/file_path.h"
  12 #include "base/files/file_util.h"
  13 #include "base/location.h"
  14 #include "base/path_service.h"
  15 #include "base/strings/string_number_conversions.h"
  16 #include "base/strings/string_util.h"
  17 #include "base/task_runner_util.h"
  18 #include "base/threading/worker_pool.h"
  19 #include "chromeos/chromeos_paths.h"
  20 #include "chromeos/dbus/blocking_method_caller.h"
  21 #include "chromeos/dbus/cryptohome_client.h"
  22 #include "crypto/sha2.h"
  23 #include "dbus/bus.h"
  24 #include "dbus/message.h"
  25 #include "dbus/object_path.h"
  26 #include "dbus/object_proxy.h"
  27 #include "policy/proto/device_management_backend.pb.h"
  28 #include "third_party/cros_system_api/dbus/service_constants.h"
  29
  30 namespace chromeos {
  31
  32 namespace {
  33
  34 // Returns a location for |file| that is specific to the given |username|.
  35 // These paths will be relative to DIR_USER_POLICY_KEYS, and can be used only
  36 // to store stub files.
  37 base::FilePath GetUserFilePath(const std::string& username, const char* file) {
  38   base::FilePath keys_path;
  39   if (!PathService::Get(chromeos::DIR_USER_POLICY_KEYS, &keys_path))
  40     return base::FilePath();
  41   const std::string sanitized =
  42       CryptohomeClient::GetStubSanitizedUsername(username);
  43   return keys_path.AppendASCII(sanitized).AppendASCII(file);
  44 }
  45
  46 // Helper to asynchronously retrieve a file's content.
  47 std::string GetFileContent(const base::FilePath& path) {
  48   std::string result;
  49   if (!path.empty())
  50     base::ReadFileToString(path, &result);
  51   return result;
  52 }
  53
  54 // Helper to write a file in a background thread.
  55 void StoreFile(const base::FilePath& path, const std::string& data) {
  56   const int size = static_cast<int>(data.size());
  57   if (path.empty() ||
  58       !base::CreateDirectory(path.DirName()) ||
  59       base::WriteFile(path, data.data(), size) != size) {
  60     LOG(WARNING) << "Failed to write to " << path.value();
  61   }
  62 }
  63
  64 // Creates a pair of file descriptors that form a conduit for trustworthy
  65 // transfer of credentials between Chrome and the session_manager
  66 void CreateValidCredConduit(dbus::FileDescriptor* local_auth_fd,
  67                             dbus::FileDescriptor* remote_auth_fd) {
  68   int sockets[2] = {-1, -1};
  69   if (socketpair(AF_UNIX, SOCK_STREAM, 0, sockets) < 0) {
  70     PLOG(ERROR) << "Failed to create a unix domain socketpair";
  71     return;
  72   }
  73
  74   local_auth_fd->PutValue(sockets[0]);
  75   local_auth_fd->CheckValidity();
  76
  77   remote_auth_fd->PutValue(sockets[1]);
  78   remote_auth_fd->CheckValidity();
  79 }
  80
  81 }  // namespace
  82
  83 // The SessionManagerClient implementation used in production.
  84 class SessionManagerClientImpl : public SessionManagerClient {
  85  public:
  86   SessionManagerClientImpl()
  87       : session_manager_proxy_(NULL),
  88         screen_is_locked_(false),
  89         weak_ptr_factory_(this) {}
  90
  91   ~SessionManagerClientImpl() override {}
  92
  93   // SessionManagerClient overrides:
  94   void SetStubDelegate(StubDelegate* delegate) override {
  95     // Do nothing; this isn't a stub implementation.
  96   }
  97
  98   void AddObserver(Observer* observer) override {
  99     observers_.AddObserver(observer);
 100   }
 101
 102   void RemoveObserver(Observer* observer) override {
 103     observers_.RemoveObserver(observer);
 104   }
 105
 106   bool HasObserver(const Observer* observer) const override {
 107     return observers_.HasObserver(observer);
 108   }
 109
 110   bool IsScreenLocked() const override { return screen_is_locked_; }
 111
 112   void EmitLoginPromptVisible() override {
 113     SimpleMethodCallToSessionManager(
 114         login_manager::kSessionManagerEmitLoginPromptVisible);
 115     FOR_EACH_OBSERVER(Observer, observers_, EmitLoginPromptVisibleCalled());
 116   }
 117
 118   void RestartJob(int pid, const std::string& command_line) override {
 119     dbus::ScopedFileDescriptor local_auth_fd(new dbus::FileDescriptor);
 120     dbus::ScopedFileDescriptor remote_auth_fd(new dbus::FileDescriptor);
 121
 122     // The session_manager provides a new method to replace RestartJob, called
 123     // RestartJobWithAuth, that is able to be used correctly within a PID
 124     // namespace. To use it, the caller must create a unix domain socket pair
 125     // and pass one end over dbus while holding the local end open for the
 126     // duration of the call.
 127     // Here, we call CreateValidCredConduit() to create the socket pair,
 128     // and then pass both ends along to CallRestartJobWithValidFd(), which
 129     // takes care of them from there.
 130     // NB: PostTaskAndReply ensures that the second callback (which owns the
 131     //     ScopedFileDescriptor objects) outlives the first, so passing the
 132     //     bare pointers to CreateValidCredConduit is safe...
 133     //     -- BUT --
 134     //     you have to grab pointers to the contents of {local,remote}_auth_fd
 135     //     _before_ they're acted on by base::Passed() below. Passing ownership
 136     //     of the ScopedFileDescriptor objects to the callback actually nulls
 137     //     out the storage inside the local instances. Since there are
 138     //     no guarantees about the order of evaluation of arguments in a
 139     //     function call, merely having them appear earlier among the args
 140     //     to PostTaskAndReply() is not enough. Relying on this crashed on
 141     //     some platforms.
 142     base::Closure create_credentials_conduit_closure = base::Bind(
 143         &CreateValidCredConduit, local_auth_fd.get(), remote_auth_fd.get());
 144
 145     base::WorkerPool::PostTaskAndReply(
 146         FROM_HERE, create_credentials_conduit_closure,
 147         base::Bind(&SessionManagerClientImpl::CallRestartJobWithValidFd,
 148                    weak_ptr_factory_.GetWeakPtr(), base::Passed(&local_auth_fd),
 149                    base::Passed(&remote_auth_fd), command_line),
 150         false);
 151   }
 152
 153   void StartSession(const std::string& user_email) override {
 154     dbus::MethodCall method_call(login_manager::kSessionManagerInterface,
 155                                  login_manager::kSessionManagerStartSession);
 156     dbus::MessageWriter writer(&method_call);
 157     writer.AppendString(user_email);
 158     writer.AppendString("");  // Unique ID is deprecated
 159     session_manager_proxy_->CallMethod(
 160         &method_call,
 161         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
 162         base::Bind(&SessionManagerClientImpl::OnStartSession,
 163                    weak_ptr_factory_.GetWeakPtr()));
 164   }
 165
 166   void StopSession() override {
 167     dbus::MethodCall method_call(login_manager::kSessionManagerInterface,
 168                                  login_manager::kSessionManagerStopSession);
 169     dbus::MessageWriter writer(&method_call);
 170     writer.AppendString("");  // Unique ID is deprecated
 171     session_manager_proxy_->CallMethod(
 172         &method_call,
 173         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
 174         base::Bind(&SessionManagerClientImpl::OnStopSession,
 175                    weak_ptr_factory_.GetWeakPtr()));
 176   }
 177
 178   void StartDeviceWipe() override {
 179     dbus::MethodCall method_call(login_manager::kSessionManagerInterface,
 180                                  login_manager::kSessionManagerStartDeviceWipe);
 181     session_manager_proxy_->CallMethod(
 182         &method_call,
 183         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
 184         base::Bind(&SessionManagerClientImpl::OnDeviceWipe,
 185                    weak_ptr_factory_.GetWeakPtr()));
 186   }
 187
 188   void RequestLockScreen() override {
 189     SimpleMethodCallToSessionManager(login_manager::kSessionManagerLockScreen);
 190   }
 191
 192   void NotifyLockScreenShown() override {
 193     SimpleMethodCallToSessionManager(
 194         login_manager::kSessionManagerHandleLockScreenShown);
 195   }
 196
 197   void NotifyLockScreenDismissed() override {
 198     SimpleMethodCallToSessionManager(
 199         login_manager::kSessionManagerHandleLockScreenDismissed);
 200   }
 201
 202   void NotifySupervisedUserCreationStarted() override {
 203     SimpleMethodCallToSessionManager(
 204         login_manager::kSessionManagerHandleSupervisedUserCreationStarting);
 205   }
 206
 207   void NotifySupervisedUserCreationFinished() override {
 208     SimpleMethodCallToSessionManager(
 209         login_manager::kSessionManagerHandleSupervisedUserCreationFinished);
 210   }
 211
 212   void RetrieveActiveSessions(const ActiveSessionsCallback& callback) override {
 213     dbus::MethodCall method_call(
 214         login_manager::kSessionManagerInterface,
 215         login_manager::kSessionManagerRetrieveActiveSessions);
 216
 217     session_manager_proxy_->CallMethod(
 218         &method_call,
 219         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
 220         base::Bind(&SessionManagerClientImpl::OnRetrieveActiveSessions,
 221                    weak_ptr_factory_.GetWeakPtr(),
 222                    login_manager::kSessionManagerRetrieveActiveSessions,
 223                    callback));
 224   }
 225
 226   void RetrieveDevicePolicy(const RetrievePolicyCallback& callback) override {
 227     dbus::MethodCall method_call(login_manager::kSessionManagerInterface,
 228                                  login_manager::kSessionManagerRetrievePolicy);
 229     session_manager_proxy_->CallMethod(
 230         &method_call,
 231         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
 232         base::Bind(&SessionManagerClientImpl::OnRetrievePolicy,
 233                    weak_ptr_factory_.GetWeakPtr(),
 234                    login_manager::kSessionManagerRetrievePolicy,
 235                    callback));
 236   }
 237
 238   void RetrievePolicyForUser(const std::string& username,
 239                              const RetrievePolicyCallback& callback) override {
 240     CallRetrievePolicyByUsername(
 241         login_manager::kSessionManagerRetrievePolicyForUser,
 242         username,
 243         callback);
 244   }
 245
 246   std::string BlockingRetrievePolicyForUser(
 247       const std::string& username) override {
 248     dbus::MethodCall method_call(
 249         login_manager::kSessionManagerInterface,
 250         login_manager::kSessionManagerRetrievePolicyForUser);
 251     dbus::MessageWriter writer(&method_call);
 252     writer.AppendString(username);
 253     scoped_ptr<dbus::Response> response =
 254         blocking_method_caller_->CallMethodAndBlock(&method_call);
 255     std::string policy;
 256     ExtractString(login_manager::kSessionManagerRetrievePolicyForUser,
 257                   response.get(),
 258                   &policy);
 259     return policy;
 260   }
 261
 262   void RetrieveDeviceLocalAccountPolicy(
 263       const std::string& account_name,
 264       const RetrievePolicyCallback& callback) override {
 265     CallRetrievePolicyByUsername(
 266         login_manager::kSessionManagerRetrieveDeviceLocalAccountPolicy,
 267         account_name,
 268         callback);
 269   }
 270
 271   void StoreDevicePolicy(const std::string& policy_blob,
 272                          const StorePolicyCallback& callback) override {
 273     dbus::MethodCall method_call(login_manager::kSessionManagerInterface,
 274                                  login_manager::kSessionManagerStorePolicy);
 275     dbus::MessageWriter writer(&method_call);
 276     // static_cast does not work due to signedness.
 277     writer.AppendArrayOfBytes(
 278         reinterpret_cast<const uint8*>(policy_blob.data()), policy_blob.size());
 279     session_manager_proxy_->CallMethod(
 280         &method_call,
 281         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
 282         base::Bind(&SessionManagerClientImpl::OnStorePolicy,
 283                    weak_ptr_factory_.GetWeakPtr(),
 284                    login_manager::kSessionManagerStorePolicy,
 285                    callback));
 286   }
 287
 288   void StorePolicyForUser(const std::string& username,
 289                           const std::string& policy_blob,
 290                           const StorePolicyCallback& callback) override {
 291     CallStorePolicyByUsername(login_manager::kSessionManagerStorePolicyForUser,
 292                               username,
 293                               policy_blob,
 294                               callback);
 295   }
 296
 297   void StoreDeviceLocalAccountPolicy(
 298       const std::string& account_name,
 299       const std::string& policy_blob,
 300       const StorePolicyCallback& callback) override {
 301     CallStorePolicyByUsername(
 302         login_manager::kSessionManagerStoreDeviceLocalAccountPolicy,
 303         account_name,
 304         policy_blob,
 305         callback);
 306   }
 307
 308   void SetFlagsForUser(const std::string& username,
 309                        const std::vector<std::string>& flags) override {
 310     dbus::MethodCall method_call(login_manager::kSessionManagerInterface,
 311                                  login_manager::kSessionManagerSetFlagsForUser);
 312     dbus::MessageWriter writer(&method_call);
 313     writer.AppendString(username);
 314     writer.AppendArrayOfStrings(flags);
 315     session_manager_proxy_->CallMethod(
 316         &method_call,
 317         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
 318         dbus::ObjectProxy::EmptyResponseCallback());
 319   }
 320
 321   void GetServerBackedStateKeys(const StateKeysCallback& callback) override {
 322     dbus::MethodCall method_call(
 323         login_manager::kSessionManagerInterface,
 324         login_manager::kSessionManagerGetServerBackedStateKeys);
 325
 326     session_manager_proxy_->CallMethod(
 327         &method_call,
 328         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
 329         base::Bind(&SessionManagerClientImpl::OnGetServerBackedStateKeys,
 330                    weak_ptr_factory_.GetWeakPtr(),
 331                    callback));
 332   }
 333
 334  protected:
 335   void Init(dbus::Bus* bus) override {
 336     session_manager_proxy_ = bus->GetObjectProxy(
 337         login_manager::kSessionManagerServiceName,
 338         dbus::ObjectPath(login_manager::kSessionManagerServicePath));
 339     blocking_method_caller_.reset(
 340         new BlockingMethodCaller(bus, session_manager_proxy_));
 341
 342     // Signals emitted on the session manager's interface.
 343     session_manager_proxy_->ConnectToSignal(
 344         login_manager::kSessionManagerInterface,
 345         login_manager::kOwnerKeySetSignal,
 346         base::Bind(&SessionManagerClientImpl::OwnerKeySetReceived,
 347                    weak_ptr_factory_.GetWeakPtr()),
 348         base::Bind(&SessionManagerClientImpl::SignalConnected,
 349                    weak_ptr_factory_.GetWeakPtr()));
 350     session_manager_proxy_->ConnectToSignal(
 351         login_manager::kSessionManagerInterface,
 352         login_manager::kPropertyChangeCompleteSignal,
 353         base::Bind(&SessionManagerClientImpl::PropertyChangeCompleteReceived,
 354                    weak_ptr_factory_.GetWeakPtr()),
 355         base::Bind(&SessionManagerClientImpl::SignalConnected,
 356                    weak_ptr_factory_.GetWeakPtr()));
 357     session_manager_proxy_->ConnectToSignal(
 358         login_manager::kSessionManagerInterface,
 359         login_manager::kScreenIsLockedSignal,
 360         base::Bind(&SessionManagerClientImpl::ScreenIsLockedReceived,
 361                    weak_ptr_factory_.GetWeakPtr()),
 362         base::Bind(&SessionManagerClientImpl::SignalConnected,
 363                    weak_ptr_factory_.GetWeakPtr()));
 364     session_manager_proxy_->ConnectToSignal(
 365         login_manager::kSessionManagerInterface,
 366         login_manager::kScreenIsUnlockedSignal,
 367         base::Bind(&SessionManagerClientImpl::ScreenIsUnlockedReceived,
 368                    weak_ptr_factory_.GetWeakPtr()),
 369         base::Bind(&SessionManagerClientImpl::SignalConnected,
 370                    weak_ptr_factory_.GetWeakPtr()));
 371   }
 372
 373  private:
 374   // Makes a method call to the session manager with no arguments and no
 375   // response.
 376   void SimpleMethodCallToSessionManager(const std::string& method_name) {
 377     dbus::MethodCall method_call(login_manager::kSessionManagerInterface,
 378                                  method_name);
 379     session_manager_proxy_->CallMethod(
 380         &method_call,
 381         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
 382         dbus::ObjectProxy::EmptyResponseCallback());
 383   }
 384
 385   // Helper for RetrieveDeviceLocalAccountPolicy and RetrievePolicyForUser.
 386   void CallRetrievePolicyByUsername(const std::string& method_name,
 387                                     const std::string& username,
 388                                     const RetrievePolicyCallback& callback) {
 389     dbus::MethodCall method_call(login_manager::kSessionManagerInterface,
 390                                  method_name);
 391     dbus::MessageWriter writer(&method_call);
 392     writer.AppendString(username);
 393     session_manager_proxy_->CallMethod(
 394         &method_call,
 395         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
 396         base::Bind(
 397             &SessionManagerClientImpl::OnRetrievePolicy,
 398             weak_ptr_factory_.GetWeakPtr(),
 399             method_name,
 400             callback));
 401   }
 402
 403   void CallStorePolicyByUsername(const std::string& method_name,
 404                                  const std::string& username,
 405                                  const std::string& policy_blob,
 406                                  const StorePolicyCallback& callback) {
 407     dbus::MethodCall method_call(login_manager::kSessionManagerInterface,
 408                                  method_name);
 409     dbus::MessageWriter writer(&method_call);
 410     writer.AppendString(username);
 411     // static_cast does not work due to signedness.
 412     writer.AppendArrayOfBytes(
 413         reinterpret_cast<const uint8*>(policy_blob.data()), policy_blob.size());
 414     session_manager_proxy_->CallMethod(
 415         &method_call,
 416         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
 417         base::Bind(
 418             &SessionManagerClientImpl::OnStorePolicy,
 419             weak_ptr_factory_.GetWeakPtr(),
 420             method_name,
 421             callback));
 422   }
 423
 424   // Calls RestartJobWithAuth to tell the session manager to restart the
 425   // browser using the contents of command_line, authorizing the call
 426   // using credentials acquired via remote_auth_fd.
 427   // Ownership of local_auth_fd is held for the duration of the dbus call.
 428   void CallRestartJobWithValidFd(dbus::ScopedFileDescriptor local_auth_fd,
 429                                  dbus::ScopedFileDescriptor remote_auth_fd,
 430                                  const std::string& command_line) {
 431     dbus::MethodCall method_call(
 432         login_manager::kSessionManagerInterface,
 433         login_manager::kSessionManagerRestartJobWithAuth);
 434     dbus::MessageWriter writer(&method_call);
 435     writer.AppendFileDescriptor(*remote_auth_fd);
 436     writer.AppendString(command_line);
 437
 438     // Ownership of local_auth_fd is passed to the callback that is to be
 439     // called on completion of this method call. This keeps the browser end
 440     // of the socket-pair alive for the duration of the RPC.
 441     session_manager_proxy_->CallMethod(
 442         &method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
 443         base::Bind(&SessionManagerClientImpl::OnRestartJob,
 444                    weak_ptr_factory_.GetWeakPtr(),
 445                    base::Passed(&local_auth_fd)));
 446   }
 447
 448   // Called when kSessionManagerRestartJob method is complete.
 449   // Now that the call is complete, local_auth_fd can be closed and discarded,
 450   // which will happen automatically when it goes out of scope.
 451   void OnRestartJob(dbus::ScopedFileDescriptor local_auth_fd,
 452                     dbus::Response* response) {
 453     LOG_IF(ERROR, !response)
 454         << "Failed to call "
 455         << login_manager::kSessionManagerRestartJob;
 456   }
 457
 458   // Called when kSessionManagerStartSession method is complete.
 459   void OnStartSession(dbus::Response* response) {
 460     LOG_IF(ERROR, !response)
 461         << "Failed to call "
 462         << login_manager::kSessionManagerStartSession;
 463   }
 464
 465   // Called when kSessionManagerStopSession method is complete.
 466   void OnStopSession(dbus::Response* response) {
 467     LOG_IF(ERROR, !response)
 468         << "Failed to call "
 469         << login_manager::kSessionManagerStopSession;
 470   }
 471
 472   // Called when kSessionManagerStopSession method is complete.
 473   void OnDeviceWipe(dbus::Response* response) {
 474     LOG_IF(ERROR, !response)
 475         << "Failed to call "
 476         << login_manager::kSessionManagerStartDeviceWipe;
 477   }
 478
 479   // Called when kSessionManagerRetrieveActiveSessions method is complete.
 480   void OnRetrieveActiveSessions(const std::string& method_name,
 481                                 const ActiveSessionsCallback& callback,
 482                                 dbus::Response* response) {
 483     ActiveSessionsMap sessions;
 484     bool success = false;
 485     if (!response) {
 486       LOG(ERROR) << "Failed to call " << method_name;
 487       callback.Run(sessions, success);
 488       return;
 489     }
 490
 491     dbus::MessageReader reader(response);
 492     dbus::MessageReader array_reader(NULL);
 493
 494     if (!reader.PopArray(&array_reader)) {
 495       LOG(ERROR) << method_name << " response is incorrect: "
 496                  << response->ToString();
 497     } else {
 498       while (array_reader.HasMoreData()) {
 499         dbus::MessageReader dict_entry_reader(NULL);
 500         std::string key;
 501         std::string value;
 502         if (!array_reader.PopDictEntry(&dict_entry_reader) ||
 503             !dict_entry_reader.PopString(&key) ||
 504             !dict_entry_reader.PopString(&value)) {
 505           LOG(ERROR) << method_name << " response is incorrect: "
 506                      << response->ToString();
 507         } else {
 508           sessions[key] = value;
 509         }
 510       }
 511       success = true;
 512     }
 513     callback.Run(sessions, success);
 514   }
 515
 516   void ExtractString(const std::string& method_name,
 517                      dbus::Response* response,
 518                      std::string* extracted) {
 519     if (!response) {
 520       LOG(ERROR) << "Failed to call " << method_name;
 521       return;
 522     }
 523     dbus::MessageReader reader(response);
 524     const uint8* values = NULL;
 525     size_t length = 0;
 526     if (!reader.PopArrayOfBytes(&values, &length)) {
 527       LOG(ERROR) << "Invalid response: " << response->ToString();
 528       return;
 529     }
 530     // static_cast does not work due to signedness.
 531     extracted->assign(reinterpret_cast<const char*>(values), length);
 532   }
 533
 534   // Called when kSessionManagerRetrievePolicy or
 535   // kSessionManagerRetrievePolicyForUser method is complete.
 536   void OnRetrievePolicy(const std::string& method_name,
 537                         const RetrievePolicyCallback& callback,
 538                         dbus::Response* response) {
 539     std::string serialized_proto;
 540     ExtractString(method_name, response, &serialized_proto);
 541     callback.Run(serialized_proto);
 542   }
 543
 544   // Called when kSessionManagerStorePolicy or kSessionManagerStorePolicyForUser
 545   // method is complete.
 546   void OnStorePolicy(const std::string& method_name,
 547                      const StorePolicyCallback& callback,
 548                      dbus::Response* response) {
 549     bool success = false;
 550     if (!response) {
 551       LOG(ERROR) << "Failed to call " << method_name;
 552     } else {
 553       dbus::MessageReader reader(response);
 554       if (!reader.PopBool(&success))
 555         LOG(ERROR) << "Invalid response: " << response->ToString();
 556     }
 557     callback.Run(success);
 558   }
 559
 560   // Called when the owner key set signal is received.
 561   void OwnerKeySetReceived(dbus::Signal* signal) {
 562     dbus::MessageReader reader(signal);
 563     std::string result_string;
 564     if (!reader.PopString(&result_string)) {
 565       LOG(ERROR) << "Invalid signal: " << signal->ToString();
 566       return;
 567     }
 568     const bool success = base::StartsWith(result_string, "success",
 569                                           base::CompareCase::INSENSITIVE_ASCII);
 570     FOR_EACH_OBSERVER(Observer, observers_, OwnerKeySet(success));
 571   }
 572
 573   // Called when the property change complete signal is received.
 574   void PropertyChangeCompleteReceived(dbus::Signal* signal) {
 575     dbus::MessageReader reader(signal);
 576     std::string result_string;
 577     if (!reader.PopString(&result_string)) {
 578       LOG(ERROR) << "Invalid signal: " << signal->ToString();
 579       return;
 580     }
 581     const bool success = base::StartsWith(result_string, "success",
 582                                           base::CompareCase::INSENSITIVE_ASCII);
 583     FOR_EACH_OBSERVER(Observer, observers_, PropertyChangeComplete(success));
 584   }
 585
 586   void ScreenIsLockedReceived(dbus::Signal* signal) {
 587     screen_is_locked_ = true;
 588     FOR_EACH_OBSERVER(Observer, observers_, ScreenIsLocked());
 589   }
 590
 591   void ScreenIsUnlockedReceived(dbus::Signal* signal) {
 592     screen_is_locked_ = false;
 593     FOR_EACH_OBSERVER(Observer, observers_, ScreenIsUnlocked());
 594   }
 595
 596   // Called when the object is connected to the signal.
 597   void SignalConnected(const std::string& interface_name,
 598                        const std::string& signal_name,
 599                        bool success) {
 600     LOG_IF(ERROR, !success) << "Failed to connect to " << signal_name;
 601   }
 602
 603   // Called when kSessionManagerGetServerBackedStateKeys method is complete.
 604   void OnGetServerBackedStateKeys(const StateKeysCallback& callback,
 605                                   dbus::Response* response) {
 606     std::vector<std::string> state_keys;
 607     if (!response) {
 608       LOG(ERROR) << "Failed to call "
 609                  << login_manager::kSessionManagerGetServerBackedStateKeys;
 610     } else {
 611       dbus::MessageReader reader(response);
 612       dbus::MessageReader array_reader(NULL);
 613
 614       if (!reader.PopArray(&array_reader)) {
 615         LOG(ERROR) << "Bad response: " << response->ToString();
 616       } else {
 617         while (array_reader.HasMoreData()) {
 618           const uint8* data = NULL;
 619           size_t size = 0;
 620           if (!array_reader.PopArrayOfBytes(&data, &size)) {
 621             LOG(ERROR) << "Bad response: " << response->ToString();
 622             state_keys.clear();
 623             break;
 624           }
 625           state_keys.push_back(
 626               std::string(reinterpret_cast<const char*>(data), size));
 627         }
 628       }
 629     }
 630
 631     if (!callback.is_null())
 632       callback.Run(state_keys);
 633   }
 634
 635
 636   dbus::ObjectProxy* session_manager_proxy_;
 637   scoped_ptr<BlockingMethodCaller> blocking_method_caller_;
 638   base::ObserverList<Observer> observers_;
 639
 640   // Most recent screen-lock state received from session_manager.
 641   bool screen_is_locked_;
 642
 643   // Note: This should remain the last member so it'll be destroyed and
 644   // invalidate its weak pointers before any other members are destroyed.
 645   base::WeakPtrFactory<SessionManagerClientImpl> weak_ptr_factory_;
 646
 647   DISALLOW_COPY_AND_ASSIGN(SessionManagerClientImpl);
 648 };
 649
 650 // The SessionManagerClient implementation used on Linux desktop,
 651 // which does nothing.
 652 class SessionManagerClientStubImpl : public SessionManagerClient {
 653  public:
 654   SessionManagerClientStubImpl() : delegate_(NULL), screen_is_locked_(false) {}
 655   ~SessionManagerClientStubImpl() override {}
 656
 657   // SessionManagerClient overrides
 658   void Init(dbus::Bus* bus) override {}
 659   void SetStubDelegate(StubDelegate* delegate) override {
 660     delegate_ = delegate;
 661   }
 662   void AddObserver(Observer* observer) override {
 663     observers_.AddObserver(observer);
 664   }
 665   void RemoveObserver(Observer* observer) override {
 666     observers_.RemoveObserver(observer);
 667   }
 668   bool HasObserver(const Observer* observer) const override {
 669     return observers_.HasObserver(observer);
 670   }
 671   bool IsScreenLocked() const override { return screen_is_locked_; }
 672   void EmitLoginPromptVisible() override {}
 673   void RestartJob(int pid, const std::string& command_line) override {}
 674   void StartSession(const std::string& user_email) override {}
 675   void StopSession() override {}
 676   void NotifySupervisedUserCreationStarted() override {}
 677   void NotifySupervisedUserCreationFinished() override {}
 678   void StartDeviceWipe() override {}
 679   void RequestLockScreen() override {
 680     if (delegate_)
 681       delegate_->LockScreenForStub();
 682   }
 683   void NotifyLockScreenShown() override {
 684     screen_is_locked_ = true;
 685     FOR_EACH_OBSERVER(Observer, observers_, ScreenIsLocked());
 686   }
 687   void NotifyLockScreenDismissed() override {
 688     screen_is_locked_ = false;
 689     FOR_EACH_OBSERVER(Observer, observers_, ScreenIsUnlocked());
 690   }
 691   void RetrieveActiveSessions(const ActiveSessionsCallback& callback) override {
 692   }
 693   void RetrieveDevicePolicy(const RetrievePolicyCallback& callback) override {
 694     base::FilePath owner_key_path;
 695     if (!PathService::Get(chromeos::FILE_OWNER_KEY, &owner_key_path)) {
 696       callback.Run("");
 697       return;
 698     }
 699     base::FilePath device_policy_path =
 700         owner_key_path.DirName().AppendASCII("stub_device_policy");
 701     base::PostTaskAndReplyWithResult(
 702         base::WorkerPool::GetTaskRunner(false).get(),
 703         FROM_HERE,
 704         base::Bind(&GetFileContent, device_policy_path),
 705         callback);
 706   }
 707   void RetrievePolicyForUser(const std::string& username,
 708                              const RetrievePolicyCallback& callback) override {
 709     base::PostTaskAndReplyWithResult(
 710         base::WorkerPool::GetTaskRunner(false).get(),
 711         FROM_HERE,
 712         base::Bind(&GetFileContent, GetUserFilePath(username, "stub_policy")),
 713         callback);
 714   }
 715   std::string BlockingRetrievePolicyForUser(
 716       const std::string& username) override {
 717     return GetFileContent(GetUserFilePath(username, "stub_policy"));
 718   }
 719   void RetrieveDeviceLocalAccountPolicy(
 720       const std::string& account_name,
 721       const RetrievePolicyCallback& callback) override {
 722     RetrievePolicyForUser(account_name, callback);
 723   }
 724   void StoreDevicePolicy(const std::string& policy_blob,
 725                          const StorePolicyCallback& callback) override {
 726     enterprise_management::PolicyFetchResponse response;
 727     base::FilePath owner_key_path;
 728     if (!response.ParseFromString(policy_blob) ||
 729         !PathService::Get(chromeos::FILE_OWNER_KEY, &owner_key_path)) {
 730       callback.Run(false);
 731       return;
 732     }
 733
 734     if (response.has_new_public_key()) {
 735       base::WorkerPool::PostTask(
 736           FROM_HERE,
 737           base::Bind(&StoreFile, owner_key_path, response.new_public_key()),
 738           false);
 739     }
 740
 741     // Chrome will attempt to retrieve the device policy right after storing
 742     // during enrollment, so make sure it's written before signaling
 743     // completion.
 744     // Note also that the owner key will be written before the device policy,
 745     // if it was present in the blob.
 746     base::FilePath device_policy_path =
 747         owner_key_path.DirName().AppendASCII("stub_device_policy");
 748     base::WorkerPool::PostTaskAndReply(
 749         FROM_HERE,
 750         base::Bind(&StoreFile, device_policy_path, policy_blob),
 751         base::Bind(callback, true),
 752         false);
 753   }
 754   void StorePolicyForUser(const std::string& username,
 755                           const std::string& policy_blob,
 756                           const StorePolicyCallback& callback) override {
 757     // The session manager writes the user policy key to a well-known
 758     // location. Do the same with the stub impl, so that user policy works and
 759     // can be tested on desktop builds.
 760     enterprise_management::PolicyFetchResponse response;
 761     if (!response.ParseFromString(policy_blob)) {
 762       callback.Run(false);
 763       return;
 764     }
 765
 766     if (response.has_new_public_key()) {
 767       base::FilePath key_path = GetUserFilePath(username, "policy.pub");
 768       base::WorkerPool::PostTask(
 769           FROM_HERE,
 770           base::Bind(&StoreFile, key_path, response.new_public_key()),
 771           false);
 772     }
 773
 774     // This file isn't read directly by Chrome, but is used by this class to
 775     // reload the user policy across restarts.
 776     base::FilePath stub_policy_path = GetUserFilePath(username, "stub_policy");
 777     base::WorkerPool::PostTaskAndReply(
 778         FROM_HERE,
 779         base::Bind(&StoreFile, stub_policy_path, policy_blob),
 780         base::Bind(callback, true),
 781         false);
 782   }
 783   void StoreDeviceLocalAccountPolicy(
 784       const std::string& account_name,
 785       const std::string& policy_blob,
 786       const StorePolicyCallback& callback) override {
 787     StorePolicyForUser(account_name, policy_blob, callback);
 788   }
 789   void SetFlagsForUser(const std::string& username,
 790                        const std::vector<std::string>& flags) override {}
 791
 792   void GetServerBackedStateKeys(const StateKeysCallback& callback) override {
 793     std::vector<std::string> state_keys;
 794     for (int i = 0; i < 5; ++i)
 795       state_keys.push_back(crypto::SHA256HashString(base::IntToString(i)));
 796
 797     if (!callback.is_null())
 798       callback.Run(state_keys);
 799   }
 800
 801  private:
 802   StubDelegate* delegate_;  // Weak pointer; may be NULL.
 803   base::ObserverList<Observer> observers_;
 804   std::string device_policy_;
 805   bool screen_is_locked_;
 806
 807   DISALLOW_COPY_AND_ASSIGN(SessionManagerClientStubImpl);
 808 };
 809
 810 SessionManagerClient::SessionManagerClient() {
 811 }
 812
 813 SessionManagerClient::~SessionManagerClient() {
 814 }
 815
 816 SessionManagerClient* SessionManagerClient::Create(
 817     DBusClientImplementationType type) {
 818   if (type == REAL_DBUS_CLIENT_IMPLEMENTATION)
 819     return new SessionManagerClientImpl();
 820   DCHECK_EQ(STUB_DBUS_CLIENT_IMPLEMENTATION, type);
 821   return new SessionManagerClientStubImpl();
 822 }
 823
 824 }  // namespace chromeos