update_engine_client.cc - android_system_update_engine - Gitiles

 //
 // Copyright (C) 2012 The Android Open Source Project
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //      http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 //

 #include <inttypes.h>
 #include <sysexits.h>
 #include <unistd.h>

 #include <string>

 #include <base/bind.h>
 #include <base/command_line.h>
 #include <base/logging.h>
 #include <base/macros.h>
 #include <chromeos/daemons/dbus_daemon.h>
 #include <chromeos/flag_helper.h>
 #include <dbus/bus.h>
 #include <update_engine/dbus-constants.h>
 #include <update_engine/dbus-proxies.h>

 using std::string;
 using update_engine::kAttemptUpdateFlagNonInteractive;
 using update_engine::kUpdateEngineServiceName;

 namespace {

 // Constant to signal that we need to continue running the daemon after
 // initialization.
 const int kContinueRunning = -1;

 class UpdateEngineClient : public chromeos::DBusDaemon {
  public:
   UpdateEngineClient(int argc, char** argv) : argc_(argc), argv_(argv) {}
   ~UpdateEngineClient() override = default;

  protected:
   int OnInit() override {
     int ret = DBusDaemon::OnInit();
     if (ret != EX_OK)
       return ret;
     if (!InitProxy())
       return 1;
     // Wait for the UpdateEngine to be available or timeout.
     proxy_->GetObjectProxy()->WaitForServiceToBeAvailable(
         base::Bind(&UpdateEngineClient::OnServiceAvailable,
                    base::Unretained(this)));
     base::MessageLoop::current()->PostDelayedTask(
         FROM_HERE,
         base::Bind(&UpdateEngineClient::OnServiceAvailableTimeout,
                    base::Unretained(this)),
         base::TimeDelta::FromSeconds(10));
     return EX_OK;
   }

  private:
   bool InitProxy();

   // Callback called when the UpdateEngine service becomes available.
   void OnServiceAvailable(bool service_is_available);

   // Callback called when the UpdateEngine service doesn't become available
   // after a timeout.
   void OnServiceAvailableTimeout();


   // Callback called when a StatusUpdate signal is received.
   void OnStatusUpdateSignal(int64_t last_checked_time,
                             double progress,
                             const string& current_operation,
                             const string& new_version,
                             int64_t new_size);
   // Callback called when the OnStatusUpdateSignal() handler is registered.
   void OnStatusUpdateSignalRegistration(const string& interface,
                                         const string& signal_name,
                                         bool success);

   // Registers a callback that prints on stderr the received StatusUpdate
   // signals.
   // The daemon should continue running for this to work.
   void WatchForUpdates();

   void ResetStatus();

   // Show the status of the update engine in stdout.
   // Blocking call. Exits the program with error 1 in case of an error.
   void ShowStatus();

   // Return the current operation status, such as UPDATE_STATUS_IDLE.
   // Blocking call. Exits the program with error 1 in case of an error.
   string GetCurrentOperation();

   void Rollback(bool rollback);
   string GetRollbackPartition();
   void CheckForUpdates(const string& app_version,
                        const string& omaha_url,
                        bool interactive);

   // Reboot the device if a reboot is needed.
   // Blocking call. Ignores failures.
   void RebootIfNeeded();

   // Getter and setter for the target channel. If |get_current_channel| is true,
   // the current channel instead of the target channel will be returned.
   // Blocking call. Exits the program with error 1 in case of an error.
   void SetTargetChannel(const string& target_channel, bool allow_powerwash);
   string GetChannel(bool get_current_channel);

   // Getter and setter for the updates over cellular connections.
   // Blocking call. Exits the program with error 1 in case of an error.
   void SetUpdateOverCellularPermission(bool allowed);
   bool GetUpdateOverCellularPermission();

   // Getter and setter for the updates from P2P permission.
   // Blocking call. Exits the program with error 1 in case of an error.
   void SetP2PUpdatePermission(bool enabled);
   bool GetP2PUpdatePermission();

   // This is similar to watching for updates but rather than registering
   // a signal watch, actively poll the daemon just in case it stops
   // sending notifications.
   void WaitForUpdateComplete();
   void OnUpdateCompleteCheck(int64_t last_checked_time,
                              double progress,
                              const string& current_operation,
                              const string& new_version,
                              int64_t new_size);

   // Blocking call. Exits the program with error 1 in case of an error.
   void ShowPrevVersion();

   // Returns whether the current status is such that a reboot is needed.
   // Blocking call. Exits the program with error 1 in case of an error.
   bool GetIsRebootNeeded();

   // Blocks until a reboot is needed. If the reboot is needed, exits the program
   // with 0. Otherwise it exits the program with 1 if an error occurs before
   // the reboot is needed.
   void WaitForRebootNeeded();
   void OnRebootNeededCheck(int64_t last_checked_time,
                            double progress,
                            const string& current_operation,
                            const string& new_version,
                            int64_t new_size);
   // Callback called when the OnRebootNeededCheck() handler is registered. This
   // is useful to check at this point if the reboot is needed, without loosing
   // any StatusUpdate signals and avoiding the race condition.
   void OnRebootNeededCheckRegistration(const string& interface,
                                        const string& signal_name,
                                        bool success);

   // Main method that parses and triggers all the actions based on the passed
   // flags.
   int ProcessFlags();

   // DBus Proxy to the update_engine daemon object used for all the calls.
   std::unique_ptr<org::chromium::UpdateEngineInterfaceProxy> proxy_;

   // Copy of argc and argv passed to main().
   int argc_;
   char** argv_;

   // Tell whether the UpdateEngine service is available after startup.
   bool service_is_available_{false};

   DISALLOW_COPY_AND_ASSIGN(UpdateEngineClient);
 };

 bool UpdateEngineClient::InitProxy() {
   proxy_.reset(new org::chromium::UpdateEngineInterfaceProxy(bus_));

   if (!proxy_->GetObjectProxy()) {
     LOG(ERROR) << "Error getting dbus proxy for " << kUpdateEngineServiceName;
     return false;
   }
   return true;
 }

 void UpdateEngineClient::OnServiceAvailable(bool service_is_available) {
   service_is_available_ = service_is_available;
   if (!service_is_available) {
     LOG(ERROR) << "UpdateEngineService not available.";
     QuitWithExitCode(-1);
   }
   int ret = ProcessFlags();
   if (ret != kContinueRunning)
     QuitWithExitCode(ret);
 }

 void UpdateEngineClient::OnServiceAvailableTimeout() {
   if (!service_is_available_) {
     LOG(ERROR) << "Waiting for UpdateEngineService timeout. Is update_engine "
                   "daemon running?";
     QuitWithExitCode(-1);
   }
 }

 void UpdateEngineClient::OnStatusUpdateSignal(
     int64_t last_checked_time,
     double progress,
     const string& current_operation,
     const string& new_version,
     int64_t new_size) {
   LOG(INFO) << "Got status update:";
   LOG(INFO) << "  last_checked_time: " << last_checked_time;
   LOG(INFO) << "  progress: " << progress;
   LOG(INFO) << "  current_operation: " << current_operation;
   LOG(INFO) << "  new_version: " << new_version;
   LOG(INFO) << "  new_size: " << new_size;
 }

 void UpdateEngineClient::OnStatusUpdateSignalRegistration(
     const string& interface,
     const string& signal_name,
     bool success) {
   VLOG(1) << "OnStatusUpdateSignalRegistration(" << interface << ", "
           << signal_name << ", " << success << ");";
   if (!success) {
     LOG(ERROR) << "Couldn't connect to the " << signal_name << " signal.";
     exit(1);
   }
 }

 void UpdateEngineClient::WatchForUpdates() {
   proxy_->RegisterStatusUpdateSignalHandler(
       base::Bind(&UpdateEngineClient::OnStatusUpdateSignal,
                  base::Unretained(this)),
       base::Bind(&UpdateEngineClient::OnStatusUpdateSignalRegistration,
                  base::Unretained(this)));
 }

 void UpdateEngineClient::ResetStatus() {
   bool ret = proxy_->ResetStatus(nullptr);
   CHECK(ret) << "ResetStatus() failed.";
 }

 void UpdateEngineClient::ShowStatus() {
   int64_t last_checked_time = 0;
   double progress = 0.0;
   string current_op;
   string new_version;
   int64_t new_size = 0;

   bool ret = proxy_->GetStatus(
       &last_checked_time, &progress, &current_op, &new_version, &new_size,
       nullptr);
   CHECK(ret) << "GetStatus() failed";
   printf("LAST_CHECKED_TIME=%" PRIi64 "\nPROGRESS=%f\nCURRENT_OP=%s\n"
          "NEW_VERSION=%s\nNEW_SIZE=%" PRIi64 "\n",
          last_checked_time,
          progress,
          current_op.c_str(),
          new_version.c_str(),
          new_size);
 }

 string UpdateEngineClient::GetCurrentOperation() {
   int64_t last_checked_time = 0;
   double progress = 0.0;
   string current_op;
   string new_version;
   int64_t new_size = 0;

   bool ret = proxy_->GetStatus(
       &last_checked_time, &progress, &current_op, &new_version, &new_size,
       nullptr);
   CHECK(ret) << "GetStatus() failed";
   return current_op;
 }

 void UpdateEngineClient::Rollback(bool rollback) {
   bool ret = proxy_->AttemptRollback(rollback, nullptr);
   CHECK(ret) << "Rollback request failed.";
 }

 string UpdateEngineClient::GetRollbackPartition() {
   string rollback_partition;
   bool ret = proxy_->GetRollbackPartition(&rollback_partition, nullptr);
   CHECK(ret) << "Error while querying rollback partition availabilty.";
   return rollback_partition;
 }

 void UpdateEngineClient::CheckForUpdates(const string& app_version,
                                          const string& omaha_url,
                                          bool interactive) {
   int32_t flags = interactive ? 0 : kAttemptUpdateFlagNonInteractive;
   bool ret = proxy_->AttemptUpdateWithFlags(app_version, omaha_url, flags,
                                             nullptr);
   CHECK(ret) << "Error checking for update.";
 }

 void UpdateEngineClient::RebootIfNeeded() {
   bool ret = proxy_->RebootIfNeeded(nullptr);
   if (!ret) {
     // Reboot error code doesn't necessarily mean that a reboot
     // failed. For example, D-Bus may be shutdown before we receive the
     // result.
     LOG(INFO) << "RebootIfNeeded() failure ignored.";
   }
 }

 void UpdateEngineClient::SetTargetChannel(const string& target_channel,
                                           bool allow_powerwash) {
   bool ret = proxy_->SetChannel(target_channel, allow_powerwash, nullptr);
   CHECK(ret) << "Error setting the channel.";
   LOG(INFO) << "Channel permanently set to: " << target_channel;
 }

 string UpdateEngineClient::GetChannel(bool get_current_channel) {
   string channel;
   bool ret = proxy_->GetChannel(get_current_channel, &channel, nullptr);
   CHECK(ret) << "Error getting the channel.";
   return channel;
 }

 void UpdateEngineClient::SetUpdateOverCellularPermission(bool allowed) {
   bool ret = proxy_->SetUpdateOverCellularPermission(allowed, nullptr);
   CHECK(ret) << "Error setting the update over cellular setting.";
 }

 bool UpdateEngineClient::GetUpdateOverCellularPermission() {
   bool allowed;
   bool ret = proxy_->GetUpdateOverCellularPermission(&allowed, nullptr);
   CHECK(ret) << "Error getting the update over cellular setting.";
   return allowed;
 }

 void UpdateEngineClient::SetP2PUpdatePermission(bool enabled) {
   bool ret = proxy_->SetP2PUpdatePermission(enabled, nullptr);
   CHECK(ret) << "Error setting the peer-to-peer update setting.";
 }

 bool UpdateEngineClient::GetP2PUpdatePermission() {
   bool enabled;
   bool ret = proxy_->GetP2PUpdatePermission(&enabled, nullptr);
   CHECK(ret) << "Error getting the peer-to-peer update setting.";
   return enabled;
 }

 void UpdateEngineClient::OnUpdateCompleteCheck(
     int64_t /* last_checked_time */,
     double /* progress */,
     const string& current_operation,
     const string& /* new_version */,
     int64_t /* new_size */) {
   if (current_operation == update_engine::kUpdateStatusIdle) {
     LOG(ERROR) << "Update failed, current operations is " << current_operation;
     exit(1);
   }
   if (current_operation == update_engine::kUpdateStatusUpdatedNeedReboot) {
     LOG(INFO) << "Update succeeded -- reboot needed.";
     exit(0);
   }
 }

 void UpdateEngineClient::WaitForUpdateComplete() {
   proxy_->RegisterStatusUpdateSignalHandler(
       base::Bind(&UpdateEngineClient::OnUpdateCompleteCheck,
                  base::Unretained(this)),
       base::Bind(&UpdateEngineClient::OnStatusUpdateSignalRegistration,
                  base::Unretained(this)));
 }

 void UpdateEngineClient::ShowPrevVersion() {
   string prev_version = nullptr;

   bool ret = proxy_->GetPrevVersion(&prev_version, nullptr);;
   if (!ret) {
     LOG(ERROR) << "Error getting previous version.";
   } else {
     LOG(INFO) << "Previous version = " << prev_version;
   }
 }

 bool UpdateEngineClient::GetIsRebootNeeded() {
   return GetCurrentOperation() == update_engine::kUpdateStatusUpdatedNeedReboot;
 }

 void UpdateEngineClient::OnRebootNeededCheck(
     int64_t /* last_checked_time */,
     double /* progress */,
     const string& current_operation,
     const string& /* new_version */,
     int64_t /* new_size */) {
   if (current_operation == update_engine::kUpdateStatusUpdatedNeedReboot) {
     LOG(INFO) << "Reboot needed.";
     exit(0);
   }
 }

 void UpdateEngineClient::OnRebootNeededCheckRegistration(
     const string& interface,
     const string& signal_name,
     bool success) {
   if (GetIsRebootNeeded())
     exit(0);
   if (!success) {
     LOG(ERROR) << "Couldn't connect to the " << signal_name << " signal.";
     exit(1);
   }
 }

 // Blocks until a reboot is needed. Returns true if waiting succeeded,
 // false if an error occurred.
 void UpdateEngineClient::WaitForRebootNeeded() {
   proxy_->RegisterStatusUpdateSignalHandler(
       base::Bind(&UpdateEngineClient::OnUpdateCompleteCheck,
                  base::Unretained(this)),
       base::Bind(&UpdateEngineClient::OnStatusUpdateSignalRegistration,
                  base::Unretained(this)));
   if (GetIsRebootNeeded())
     exit(0);
 }

 int UpdateEngineClient::ProcessFlags() {
   DEFINE_string(app_version, "", "Force the current app version.");
   DEFINE_string(channel, "",
                 "Set the target channel. The device will be powerwashed if the "
                 "target channel is more stable than the current channel unless "
                 "--nopowerwash is specified.");
   DEFINE_bool(check_for_update, false, "Initiate check for updates.");
   DEFINE_bool(follow, false, "Wait for any update operations to complete."
               "Exit status is 0 if the update succeeded, and 1 otherwise.");
   DEFINE_bool(interactive, true, "Mark the update request as interactive.");
   DEFINE_string(omaha_url, "", "The URL of the Omaha update server.");
   DEFINE_string(p2p_update, "",
                 "Enables (\"yes\") or disables (\"no\") the peer-to-peer update"
                 " sharing.");
   DEFINE_bool(powerwash, true, "When performing rollback or channel change, "
               "do a powerwash or allow it respectively.");
   DEFINE_bool(reboot, false, "Initiate a reboot if needed.");
   DEFINE_bool(is_reboot_needed, false, "Exit status 0 if reboot is needed, "
               "2 if reboot is not needed or 1 if an error occurred.");
   DEFINE_bool(block_until_reboot_is_needed, false, "Blocks until reboot is "
               "needed. Returns non-zero exit status if an error occurred.");
   DEFINE_bool(reset_status, false, "Sets the status in update_engine to idle.");
   DEFINE_bool(rollback, false,
               "Perform a rollback to the previous partition. The device will "
               "be powerwashed unless --nopowerwash is specified.");
   DEFINE_bool(can_rollback, false, "Shows whether rollback partition "
               "is available.");
   DEFINE_bool(show_channel, false, "Show the current and target channels.");
   DEFINE_bool(show_p2p_update, false,
               "Show the current setting for peer-to-peer update sharing.");
   DEFINE_bool(show_update_over_cellular, false,
               "Show the current setting for updates over cellular networks.");
   DEFINE_bool(status, false, "Print the status to stdout.");
   DEFINE_bool(update, false, "Forces an update and waits for it to complete. "
               "Implies --follow.");
   DEFINE_string(update_over_cellular, "",
                 "Enables (\"yes\") or disables (\"no\") the updates over "
                 "cellular networks.");
   DEFINE_bool(watch_for_updates, false,
               "Listen for status updates and print them to the screen.");
   DEFINE_bool(prev_version, false,
               "Show the previous OS version used before the update reboot.");

   // Boilerplate init commands.
   base::CommandLine::Init(argc_, argv_);
   chromeos::FlagHelper::Init(argc_, argv_, "Chromium OS Update Engine Client");

   // Ensure there are no positional arguments.
   const std::vector<string> positional_args =
       base::CommandLine::ForCurrentProcess()->GetArgs();
   if (!positional_args.empty()) {
     LOG(ERROR) << "Found a positional argument '" << positional_args.front()
                << "'. If you want to pass a value to a flag, pass it as "
                   "--flag=value.";
     return 1;
   }

   // Update the status if requested.
   if (FLAGS_reset_status) {
     LOG(INFO) << "Setting Update Engine status to idle ...";
     ResetStatus();
     LOG(INFO) << "ResetStatus succeeded; to undo partition table changes run:\n"
                  "(D=$(rootdev -d) P=$(rootdev -s); cgpt p -i$(($(echo ${P#$D} "
                  "| sed 's/^[^0-9]*//')-1)) $D;)";
   }

   // Changes the current update over cellular network setting.
   if (!FLAGS_update_over_cellular.empty()) {
     bool allowed = FLAGS_update_over_cellular == "yes";
     if (!allowed && FLAGS_update_over_cellular != "no") {
       LOG(ERROR) << "Unknown option: \"" << FLAGS_update_over_cellular
                  << "\". Please specify \"yes\" or \"no\".";
     } else {
       SetUpdateOverCellularPermission(allowed);
     }
   }

   // Show the current update over cellular network setting.
   if (FLAGS_show_update_over_cellular) {
     bool allowed = GetUpdateOverCellularPermission();
     LOG(INFO) << "Current update over cellular network setting: "
               << (allowed ? "ENABLED" : "DISABLED");
   }

   if (!FLAGS_powerwash && !FLAGS_rollback && FLAGS_channel.empty()) {
     LOG(ERROR) << "powerwash flag only makes sense rollback or channel change";
     return 1;
   }

   // Change the P2P enabled setting.
   if (!FLAGS_p2p_update.empty()) {
     bool enabled = FLAGS_p2p_update == "yes";
     if (!enabled && FLAGS_p2p_update != "no") {
       LOG(ERROR) << "Unknown option: \"" << FLAGS_p2p_update
                  << "\". Please specify \"yes\" or \"no\".";
     } else {
       SetP2PUpdatePermission(enabled);
     }
   }

   // Show the rollback availability.
   if (FLAGS_can_rollback) {
     string rollback_partition = GetRollbackPartition();
     bool can_rollback = true;
     if (rollback_partition.empty()) {
       rollback_partition = "UNAVAILABLE";
       can_rollback = false;
     } else {
       rollback_partition = "AVAILABLE: " + rollback_partition;
     }

     LOG(INFO) << "Rollback partition: " << rollback_partition;
     if (!can_rollback) {
       return 1;
     }
   }

   // Show the current P2P enabled setting.
   if (FLAGS_show_p2p_update) {
     bool enabled = GetP2PUpdatePermission();
     LOG(INFO) << "Current update using P2P setting: "
               << (enabled ? "ENABLED" : "DISABLED");
   }

   // First, update the target channel if requested.
   if (!FLAGS_channel.empty())
     SetTargetChannel(FLAGS_channel, FLAGS_powerwash);

   // Show the current and target channels if requested.
   if (FLAGS_show_channel) {
     string current_channel = GetChannel(true);
     LOG(INFO) << "Current Channel: " << current_channel;

     string target_channel = GetChannel(false);
     if (!target_channel.empty())
       LOG(INFO) << "Target Channel (pending update): " << target_channel;
   }

   bool do_update_request = FLAGS_check_for_update | FLAGS_update |
       !FLAGS_app_version.empty() | !FLAGS_omaha_url.empty();
   if (FLAGS_update)
     FLAGS_follow = true;

   if (do_update_request && FLAGS_rollback) {
     LOG(ERROR) << "Incompatible flags specified with rollback."
                << "Rollback should not include update-related flags.";
     return 1;
   }

   if (FLAGS_rollback) {
     LOG(INFO) << "Requesting rollback.";
     Rollback(FLAGS_powerwash);
   }

   // Initiate an update check, if necessary.
   if (do_update_request) {
     LOG_IF(WARNING, FLAGS_reboot) << "-reboot flag ignored.";
     string app_version = FLAGS_app_version;
     if (FLAGS_update && app_version.empty()) {
       app_version = "ForcedUpdate";
       LOG(INFO) << "Forcing an update by setting app_version to ForcedUpdate.";
     }
     LOG(INFO) << "Initiating update check and install.";
     CheckForUpdates(app_version, FLAGS_omaha_url, FLAGS_interactive);
   }

   // These final options are all mutually exclusive with one another.
   if (FLAGS_follow + FLAGS_watch_for_updates + FLAGS_reboot +
       FLAGS_status + FLAGS_is_reboot_needed +
       FLAGS_block_until_reboot_is_needed > 1) {
     LOG(ERROR) << "Multiple exclusive options selected. "
                << "Select only one of --follow, --watch_for_updates, --reboot, "
                << "--is_reboot_needed, --block_until_reboot_is_needed, "
                << "or --status.";
     return 1;
   }

   if (FLAGS_status) {
     LOG(INFO) << "Querying Update Engine status...";
     ShowStatus();
     return 0;
   }

   if (FLAGS_follow) {
     LOG(INFO) << "Waiting for update to complete.";
     WaitForUpdateComplete();
     return kContinueRunning;
   }

   if (FLAGS_watch_for_updates) {
     LOG(INFO) << "Watching for status updates.";
     WatchForUpdates();
     return kContinueRunning;
   }

   if (FLAGS_reboot) {
     LOG(INFO) << "Requesting a reboot...";
     RebootIfNeeded();
     return 0;
   }

   if (FLAGS_prev_version) {
     ShowPrevVersion();
   }

   if (FLAGS_is_reboot_needed) {
     // In case of error GetIsRebootNeeded() will exit with 1.
     if (GetIsRebootNeeded()) {
       return 0;
     } else {
       return 2;
     }
   }

   if (FLAGS_block_until_reboot_is_needed) {
     WaitForRebootNeeded();
     return kContinueRunning;
   }

   return 0;
 }

 }  // namespace

 int main(int argc, char** argv) {
   UpdateEngineClient client(argc, argv);
   return client.Run();
 }
	//
	// Copyright (C) 2012 The Android Open Source Project
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.
	//

	#include <inttypes.h>
	#include <sysexits.h>
	#include <unistd.h>

	#include <string>

	#include <base/bind.h>
	#include <base/command_line.h>
	#include <base/logging.h>
	#include <base/macros.h>
	#include <chromeos/daemons/dbus_daemon.h>
	#include <chromeos/flag_helper.h>
	#include <dbus/bus.h>
	#include <update_engine/dbus-constants.h>
	#include <update_engine/dbus-proxies.h>

	using std::string;
	using update_engine::kAttemptUpdateFlagNonInteractive;
	using update_engine::kUpdateEngineServiceName;

	namespace {

	// Constant to signal that we need to continue running the daemon after
	// initialization.
	const int kContinueRunning = -1;

	class UpdateEngineClient : public chromeos::DBusDaemon {
	public:
	UpdateEngineClient(int argc, char** argv) : argc_(argc), argv_(argv) {}
	~UpdateEngineClient() override = default;

	protected:
	int OnInit() override {
	int ret = DBusDaemon::OnInit();
	if (ret != EX_OK)
	return ret;
	if (!InitProxy())
	return 1;
	// Wait for the UpdateEngine to be available or timeout.
	proxy_->GetObjectProxy()->WaitForServiceToBeAvailable(
	base::Bind(&UpdateEngineClient::OnServiceAvailable,
	base::Unretained(this)));
	base::MessageLoop::current()->PostDelayedTask(
	FROM_HERE,
	base::Bind(&UpdateEngineClient::OnServiceAvailableTimeout,
	base::Unretained(this)),
	base::TimeDelta::FromSeconds(10));
	return EX_OK;
	}

	private:
	bool InitProxy();

	// Callback called when the UpdateEngine service becomes available.
	void OnServiceAvailable(bool service_is_available);

	// Callback called when the UpdateEngine service doesn't become available
	// after a timeout.
	void OnServiceAvailableTimeout();


	// Callback called when a StatusUpdate signal is received.
	void OnStatusUpdateSignal(int64_t last_checked_time,
	double progress,
	const string& current_operation,
	const string& new_version,
	int64_t new_size);
	// Callback called when the OnStatusUpdateSignal() handler is registered.
	void OnStatusUpdateSignalRegistration(const string& interface,
	const string& signal_name,
	bool success);

	// Registers a callback that prints on stderr the received StatusUpdate
	// signals.
	// The daemon should continue running for this to work.
	void WatchForUpdates();

	void ResetStatus();

	// Show the status of the update engine in stdout.
	// Blocking call. Exits the program with error 1 in case of an error.
	void ShowStatus();

	// Return the current operation status, such as UPDATE_STATUS_IDLE.
	// Blocking call. Exits the program with error 1 in case of an error.
	string GetCurrentOperation();

	void Rollback(bool rollback);
	string GetRollbackPartition();
	void CheckForUpdates(const string& app_version,
	const string& omaha_url,
	bool interactive);

	// Reboot the device if a reboot is needed.
	// Blocking call. Ignores failures.
	void RebootIfNeeded();

	// Getter and setter for the target channel. If \|get_current_channel\| is true,
	// the current channel instead of the target channel will be returned.
	// Blocking call. Exits the program with error 1 in case of an error.
	void SetTargetChannel(const string& target_channel, bool allow_powerwash);
	string GetChannel(bool get_current_channel);

	// Getter and setter for the updates over cellular connections.
	// Blocking call. Exits the program with error 1 in case of an error.
	void SetUpdateOverCellularPermission(bool allowed);
	bool GetUpdateOverCellularPermission();

	// Getter and setter for the updates from P2P permission.
	// Blocking call. Exits the program with error 1 in case of an error.
	void SetP2PUpdatePermission(bool enabled);
	bool GetP2PUpdatePermission();

	// This is similar to watching for updates but rather than registering
	// a signal watch, actively poll the daemon just in case it stops
	// sending notifications.
	void WaitForUpdateComplete();
	void OnUpdateCompleteCheck(int64_t last_checked_time,
	double progress,
	const string& current_operation,
	const string& new_version,
	int64_t new_size);

	// Blocking call. Exits the program with error 1 in case of an error.
	void ShowPrevVersion();

	// Returns whether the current status is such that a reboot is needed.
	// Blocking call. Exits the program with error 1 in case of an error.
	bool GetIsRebootNeeded();

	// Blocks until a reboot is needed. If the reboot is needed, exits the program
	// with 0. Otherwise it exits the program with 1 if an error occurs before
	// the reboot is needed.
	void WaitForRebootNeeded();
	void OnRebootNeededCheck(int64_t last_checked_time,
	double progress,
	const string& current_operation,
	const string& new_version,
	int64_t new_size);
	// Callback called when the OnRebootNeededCheck() handler is registered. This
	// is useful to check at this point if the reboot is needed, without loosing
	// any StatusUpdate signals and avoiding the race condition.
	void OnRebootNeededCheckRegistration(const string& interface,
	const string& signal_name,
	bool success);

	// Main method that parses and triggers all the actions based on the passed
	// flags.
	int ProcessFlags();

	// DBus Proxy to the update_engine daemon object used for all the calls.
	std::unique_ptr<org::chromium::UpdateEngineInterfaceProxy> proxy_;

	// Copy of argc and argv passed to main().
	int argc_;
	char** argv_;

	// Tell whether the UpdateEngine service is available after startup.
	bool service_is_available_{false};

	DISALLOW_COPY_AND_ASSIGN(UpdateEngineClient);
	};

	bool UpdateEngineClient::InitProxy() {
	proxy_.reset(new org::chromium::UpdateEngineInterfaceProxy(bus_));

	if (!proxy_->GetObjectProxy()) {
	LOG(ERROR) << "Error getting dbus proxy for " << kUpdateEngineServiceName;
	return false;
	}
	return true;
	}

	void UpdateEngineClient::OnServiceAvailable(bool service_is_available) {
	service_is_available_ = service_is_available;
	if (!service_is_available) {
	LOG(ERROR) << "UpdateEngineService not available.";
	QuitWithExitCode(-1);
	}
	int ret = ProcessFlags();
	if (ret != kContinueRunning)
	QuitWithExitCode(ret);
	}

	void UpdateEngineClient::OnServiceAvailableTimeout() {
	if (!service_is_available_) {
	LOG(ERROR) << "Waiting for UpdateEngineService timeout. Is update_engine "
	"daemon running?";
	QuitWithExitCode(-1);
	}
	}

	void UpdateEngineClient::OnStatusUpdateSignal(
	int64_t last_checked_time,
	double progress,
	const string& current_operation,
	const string& new_version,
	int64_t new_size) {
	LOG(INFO) << "Got status update:";
	LOG(INFO) << " last_checked_time: " << last_checked_time;
	LOG(INFO) << " progress: " << progress;
	LOG(INFO) << " current_operation: " << current_operation;
	LOG(INFO) << " new_version: " << new_version;
	LOG(INFO) << " new_size: " << new_size;
	}

	void UpdateEngineClient::OnStatusUpdateSignalRegistration(
	const string& interface,
	const string& signal_name,
	bool success) {
	VLOG(1) << "OnStatusUpdateSignalRegistration(" << interface << ", "
	<< signal_name << ", " << success << ");";
	if (!success) {
	LOG(ERROR) << "Couldn't connect to the " << signal_name << " signal.";
	exit(1);
	}
	}

	void UpdateEngineClient::WatchForUpdates() {
	proxy_->RegisterStatusUpdateSignalHandler(
	base::Bind(&UpdateEngineClient::OnStatusUpdateSignal,
	base::Unretained(this)),
	base::Bind(&UpdateEngineClient::OnStatusUpdateSignalRegistration,
	base::Unretained(this)));
	}

	void UpdateEngineClient::ResetStatus() {
	bool ret = proxy_->ResetStatus(nullptr);
	CHECK(ret) << "ResetStatus() failed.";
	}

	void UpdateEngineClient::ShowStatus() {
	int64_t last_checked_time = 0;
	double progress = 0.0;
	string current_op;
	string new_version;
	int64_t new_size = 0;

	bool ret = proxy_->GetStatus(
	&last_checked_time, &progress, &current_op, &new_version, &new_size,
	nullptr);
	CHECK(ret) << "GetStatus() failed";
	printf("LAST_CHECKED_TIME=%" PRIi64 "\nPROGRESS=%f\nCURRENT_OP=%s\n"
	"NEW_VERSION=%s\nNEW_SIZE=%" PRIi64 "\n",
	last_checked_time,
	progress,
	current_op.c_str(),
	new_version.c_str(),
	new_size);
	}

	string UpdateEngineClient::GetCurrentOperation() {
	int64_t last_checked_time = 0;
	double progress = 0.0;
	string current_op;
	string new_version;
	int64_t new_size = 0;

	bool ret = proxy_->GetStatus(
	&last_checked_time, &progress, &current_op, &new_version, &new_size,
	nullptr);
	CHECK(ret) << "GetStatus() failed";
	return current_op;
	}

	void UpdateEngineClient::Rollback(bool rollback) {
	bool ret = proxy_->AttemptRollback(rollback, nullptr);
	CHECK(ret) << "Rollback request failed.";
	}

	string UpdateEngineClient::GetRollbackPartition() {
	string rollback_partition;
	bool ret = proxy_->GetRollbackPartition(&rollback_partition, nullptr);
	CHECK(ret) << "Error while querying rollback partition availabilty.";
	return rollback_partition;
	}

	void UpdateEngineClient::CheckForUpdates(const string& app_version,
	const string& omaha_url,
	bool interactive) {
	int32_t flags = interactive ? 0 : kAttemptUpdateFlagNonInteractive;
	bool ret = proxy_->AttemptUpdateWithFlags(app_version, omaha_url, flags,
	nullptr);
	CHECK(ret) << "Error checking for update.";
	}

	void UpdateEngineClient::RebootIfNeeded() {
	bool ret = proxy_->RebootIfNeeded(nullptr);
	if (!ret) {
	// Reboot error code doesn't necessarily mean that a reboot
	// failed. For example, D-Bus may be shutdown before we receive the
	// result.
	LOG(INFO) << "RebootIfNeeded() failure ignored.";
	}
	}

	void UpdateEngineClient::SetTargetChannel(const string& target_channel,
	bool allow_powerwash) {
	bool ret = proxy_->SetChannel(target_channel, allow_powerwash, nullptr);
	CHECK(ret) << "Error setting the channel.";
	LOG(INFO) << "Channel permanently set to: " << target_channel;
	}

	string UpdateEngineClient::GetChannel(bool get_current_channel) {
	string channel;
	bool ret = proxy_->GetChannel(get_current_channel, &channel, nullptr);
	CHECK(ret) << "Error getting the channel.";
	return channel;
	}

	void UpdateEngineClient::SetUpdateOverCellularPermission(bool allowed) {
	bool ret = proxy_->SetUpdateOverCellularPermission(allowed, nullptr);
	CHECK(ret) << "Error setting the update over cellular setting.";
	}

	bool UpdateEngineClient::GetUpdateOverCellularPermission() {
	bool allowed;
	bool ret = proxy_->GetUpdateOverCellularPermission(&allowed, nullptr);
	CHECK(ret) << "Error getting the update over cellular setting.";
	return allowed;
	}

	void UpdateEngineClient::SetP2PUpdatePermission(bool enabled) {
	bool ret = proxy_->SetP2PUpdatePermission(enabled, nullptr);
	CHECK(ret) << "Error setting the peer-to-peer update setting.";
	}

	bool UpdateEngineClient::GetP2PUpdatePermission() {
	bool enabled;
	bool ret = proxy_->GetP2PUpdatePermission(&enabled, nullptr);
	CHECK(ret) << "Error getting the peer-to-peer update setting.";
	return enabled;
	}

	void UpdateEngineClient::OnUpdateCompleteCheck(
	int64_t /* last_checked_time */,
	double /* progress */,
	const string& current_operation,
	const string& /* new_version */,
	int64_t /* new_size */) {
	if (current_operation == update_engine::kUpdateStatusIdle) {
	LOG(ERROR) << "Update failed, current operations is " << current_operation;
	exit(1);
	}
	if (current_operation == update_engine::kUpdateStatusUpdatedNeedReboot) {
	LOG(INFO) << "Update succeeded -- reboot needed.";
	exit(0);
	}
	}

	void UpdateEngineClient::WaitForUpdateComplete() {
	proxy_->RegisterStatusUpdateSignalHandler(
	base::Bind(&UpdateEngineClient::OnUpdateCompleteCheck,
	base::Unretained(this)),
	base::Bind(&UpdateEngineClient::OnStatusUpdateSignalRegistration,
	base::Unretained(this)));
	}

	void UpdateEngineClient::ShowPrevVersion() {
	string prev_version = nullptr;

	bool ret = proxy_->GetPrevVersion(&prev_version, nullptr);;
	if (!ret) {
	LOG(ERROR) << "Error getting previous version.";
	} else {
	LOG(INFO) << "Previous version = " << prev_version;
	}
	}

	bool UpdateEngineClient::GetIsRebootNeeded() {
	return GetCurrentOperation() == update_engine::kUpdateStatusUpdatedNeedReboot;
	}

	void UpdateEngineClient::OnRebootNeededCheck(
	int64_t /* last_checked_time */,
	double /* progress */,
	const string& current_operation,
	const string& /* new_version */,
	int64_t /* new_size */) {
	if (current_operation == update_engine::kUpdateStatusUpdatedNeedReboot) {
	LOG(INFO) << "Reboot needed.";
	exit(0);
	}
	}

	void UpdateEngineClient::OnRebootNeededCheckRegistration(
	const string& interface,
	const string& signal_name,
	bool success) {
	if (GetIsRebootNeeded())
	exit(0);
	if (!success) {
	LOG(ERROR) << "Couldn't connect to the " << signal_name << " signal.";
	exit(1);
	}
	}

	// Blocks until a reboot is needed. Returns true if waiting succeeded,
	// false if an error occurred.
	void UpdateEngineClient::WaitForRebootNeeded() {
	proxy_->RegisterStatusUpdateSignalHandler(
	base::Bind(&UpdateEngineClient::OnUpdateCompleteCheck,
	base::Unretained(this)),
	base::Bind(&UpdateEngineClient::OnStatusUpdateSignalRegistration,
	base::Unretained(this)));
	if (GetIsRebootNeeded())
	exit(0);
	}

	int UpdateEngineClient::ProcessFlags() {
	DEFINE_string(app_version, "", "Force the current app version.");
	DEFINE_string(channel, "",
	"Set the target channel. The device will be powerwashed if the "
	"target channel is more stable than the current channel unless "
	"--nopowerwash is specified.");
	DEFINE_bool(check_for_update, false, "Initiate check for updates.");
	DEFINE_bool(follow, false, "Wait for any update operations to complete."
	"Exit status is 0 if the update succeeded, and 1 otherwise.");
	DEFINE_bool(interactive, true, "Mark the update request as interactive.");
	DEFINE_string(omaha_url, "", "The URL of the Omaha update server.");
	DEFINE_string(p2p_update, "",
	"Enables (\"yes\") or disables (\"no\") the peer-to-peer update"
	" sharing.");
	DEFINE_bool(powerwash, true, "When performing rollback or channel change, "
	"do a powerwash or allow it respectively.");
	DEFINE_bool(reboot, false, "Initiate a reboot if needed.");
	DEFINE_bool(is_reboot_needed, false, "Exit status 0 if reboot is needed, "
	"2 if reboot is not needed or 1 if an error occurred.");
	DEFINE_bool(block_until_reboot_is_needed, false, "Blocks until reboot is "
	"needed. Returns non-zero exit status if an error occurred.");
	DEFINE_bool(reset_status, false, "Sets the status in update_engine to idle.");
	DEFINE_bool(rollback, false,
	"Perform a rollback to the previous partition. The device will "
	"be powerwashed unless --nopowerwash is specified.");
	DEFINE_bool(can_rollback, false, "Shows whether rollback partition "
	"is available.");
	DEFINE_bool(show_channel, false, "Show the current and target channels.");
	DEFINE_bool(show_p2p_update, false,
	"Show the current setting for peer-to-peer update sharing.");
	DEFINE_bool(show_update_over_cellular, false,
	"Show the current setting for updates over cellular networks.");
	DEFINE_bool(status, false, "Print the status to stdout.");
	DEFINE_bool(update, false, "Forces an update and waits for it to complete. "
	"Implies --follow.");
	DEFINE_string(update_over_cellular, "",
	"Enables (\"yes\") or disables (\"no\") the updates over "
	"cellular networks.");
	DEFINE_bool(watch_for_updates, false,
	"Listen for status updates and print them to the screen.");
	DEFINE_bool(prev_version, false,
	"Show the previous OS version used before the update reboot.");

	// Boilerplate init commands.
	base::CommandLine::Init(argc_, argv_);
	chromeos::FlagHelper::Init(argc_, argv_, "Chromium OS Update Engine Client");

	// Ensure there are no positional arguments.
	const std::vector<string> positional_args =
	base::CommandLine::ForCurrentProcess()->GetArgs();
	if (!positional_args.empty()) {
	LOG(ERROR) << "Found a positional argument '" << positional_args.front()
	<< "'. If you want to pass a value to a flag, pass it as "
	"--flag=value.";
	return 1;
	}

	// Update the status if requested.
	if (FLAGS_reset_status) {
	LOG(INFO) << "Setting Update Engine status to idle ...";
	ResetStatus();
	LOG(INFO) << "ResetStatus succeeded; to undo partition table changes run:\n"
	"(D=$(rootdev -d) P=$(rootdev -s); cgpt p -i$(($(echo ${P#$D} "
	"\| sed 's/^[^0-9]*//')-1)) $D;)";
	}

	// Changes the current update over cellular network setting.
	if (!FLAGS_update_over_cellular.empty()) {
	bool allowed = FLAGS_update_over_cellular == "yes";
	if (!allowed && FLAGS_update_over_cellular != "no") {
	LOG(ERROR) << "Unknown option: \"" << FLAGS_update_over_cellular
	<< "\". Please specify \"yes\" or \"no\".";
	} else {
	SetUpdateOverCellularPermission(allowed);
	}
	}

	// Show the current update over cellular network setting.
	if (FLAGS_show_update_over_cellular) {
	bool allowed = GetUpdateOverCellularPermission();
	LOG(INFO) << "Current update over cellular network setting: "
	<< (allowed ? "ENABLED" : "DISABLED");
	}

	if (!FLAGS_powerwash && !FLAGS_rollback && FLAGS_channel.empty()) {
	LOG(ERROR) << "powerwash flag only makes sense rollback or channel change";
	return 1;
	}

	// Change the P2P enabled setting.
	if (!FLAGS_p2p_update.empty()) {
	bool enabled = FLAGS_p2p_update == "yes";
	if (!enabled && FLAGS_p2p_update != "no") {
	LOG(ERROR) << "Unknown option: \"" << FLAGS_p2p_update
	<< "\". Please specify \"yes\" or \"no\".";
	} else {
	SetP2PUpdatePermission(enabled);
	}
	}

	// Show the rollback availability.
	if (FLAGS_can_rollback) {
	string rollback_partition = GetRollbackPartition();
	bool can_rollback = true;
	if (rollback_partition.empty()) {
	rollback_partition = "UNAVAILABLE";
	can_rollback = false;
	} else {
	rollback_partition = "AVAILABLE: " + rollback_partition;
	}

	LOG(INFO) << "Rollback partition: " << rollback_partition;
	if (!can_rollback) {
	return 1;
	}
	}

	// Show the current P2P enabled setting.
	if (FLAGS_show_p2p_update) {
	bool enabled = GetP2PUpdatePermission();
	LOG(INFO) << "Current update using P2P setting: "
	<< (enabled ? "ENABLED" : "DISABLED");
	}

	// First, update the target channel if requested.
	if (!FLAGS_channel.empty())
	SetTargetChannel(FLAGS_channel, FLAGS_powerwash);

	// Show the current and target channels if requested.
	if (FLAGS_show_channel) {
	string current_channel = GetChannel(true);
	LOG(INFO) << "Current Channel: " << current_channel;

	string target_channel = GetChannel(false);
	if (!target_channel.empty())
	LOG(INFO) << "Target Channel (pending update): " << target_channel;
	}

	bool do_update_request = FLAGS_check_for_update \| FLAGS_update \|
	!FLAGS_app_version.empty() \| !FLAGS_omaha_url.empty();
	if (FLAGS_update)
	FLAGS_follow = true;

	if (do_update_request && FLAGS_rollback) {
	LOG(ERROR) << "Incompatible flags specified with rollback."
	<< "Rollback should not include update-related flags.";
	return 1;
	}

	if (FLAGS_rollback) {
	LOG(INFO) << "Requesting rollback.";
	Rollback(FLAGS_powerwash);
	}

	// Initiate an update check, if necessary.
	if (do_update_request) {
	LOG_IF(WARNING, FLAGS_reboot) << "-reboot flag ignored.";
	string app_version = FLAGS_app_version;
	if (FLAGS_update && app_version.empty()) {
	app_version = "ForcedUpdate";
	LOG(INFO) << "Forcing an update by setting app_version to ForcedUpdate.";
	}
	LOG(INFO) << "Initiating update check and install.";
	CheckForUpdates(app_version, FLAGS_omaha_url, FLAGS_interactive);
	}

	// These final options are all mutually exclusive with one another.
	if (FLAGS_follow + FLAGS_watch_for_updates + FLAGS_reboot +
	FLAGS_status + FLAGS_is_reboot_needed +
	FLAGS_block_until_reboot_is_needed > 1) {
	LOG(ERROR) << "Multiple exclusive options selected. "
	<< "Select only one of --follow, --watch_for_updates, --reboot, "
	<< "--is_reboot_needed, --block_until_reboot_is_needed, "
	<< "or --status.";
	return 1;
	}

	if (FLAGS_status) {
	LOG(INFO) << "Querying Update Engine status...";
	ShowStatus();
	return 0;
	}

	if (FLAGS_follow) {
	LOG(INFO) << "Waiting for update to complete.";
	WaitForUpdateComplete();
	return kContinueRunning;
	}

	if (FLAGS_watch_for_updates) {
	LOG(INFO) << "Watching for status updates.";
	WatchForUpdates();
	return kContinueRunning;
	}

	if (FLAGS_reboot) {
	LOG(INFO) << "Requesting a reboot...";
	RebootIfNeeded();
	return 0;
	}

	if (FLAGS_prev_version) {
	ShowPrevVersion();
	}

	if (FLAGS_is_reboot_needed) {
	// In case of error GetIsRebootNeeded() will exit with 1.
	if (GetIsRebootNeeded()) {
	return 0;
	} else {
	return 2;
	}
	}

	if (FLAGS_block_until_reboot_is_needed) {
	WaitForRebootNeeded();
	return kContinueRunning;
	}

	return 0;
	}

	} // namespace

	int main(int argc, char** argv) {
	UpdateEngineClient client(argc, argv);
	return client.Run();
	}