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 <memory>
 #include <string>
 #include <vector>

 #include <base/bind.h>
 #include <base/command_line.h>
 #include <base/logging.h>
 #include <base/macros.h>
 #include <brillo/daemons/daemon.h>
 #include <brillo/flag_helper.h>

 #include "update_engine/client.h"
 #include "update_engine/status_update_handler.h"
 #include "update_engine/update_status.h"
 #include "update_engine/update_status_utils.h"

 using chromeos_update_engine::UpdateStatusToString;
 using std::string;
 using std::unique_ptr;
 using std::vector;
 using update_engine::UpdateStatus;

 namespace {

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

 class UpdateEngineClient : public brillo::Daemon {
  public:
   UpdateEngineClient(int argc, char** argv) : argc_(argc), argv_(argv) {
   }

   ~UpdateEngineClient() override = default;

  protected:
   int OnInit() override {
     int ret = Daemon::OnInit();
     if (ret != EX_OK) return ret;

     client_ = update_engine::UpdateEngineClient::CreateInstance();

     if (!client_) {
       LOG(ERROR) << "UpdateEngineService not available.";
       return 1;
     }

     // We can't call QuitWithExitCode from OnInit(), so we delay the execution
     // of the ProcessFlags method after the Daemon initialization is done.
     base::MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&UpdateEngineClient::ProcessFlagsAndExit,
                    base::Unretained(this)));
     return EX_OK;
   }

  private:
   // Show the status of the update engine in stdout.
   bool ShowStatus();

   // Return whether we need to reboot. 0 if reboot is needed, 1 if an error
   // occurred, 2 if no reboot is needed.
   int GetNeedReboot();

   // Main method that parses and triggers all the actions based on the passed
   // flags. Returns the exit code of the program of kContinueRunning if it
   // should not exit.
   int ProcessFlags();

   // Processes the flags and exits the program accordingly.
   void ProcessFlagsAndExit();

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

   // Library-based client
   unique_ptr<update_engine::UpdateEngineClient> client_;

   // Pointers to handlers for cleanup
   vector<unique_ptr<update_engine::StatusUpdateHandler>> handlers_;

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

   DISALLOW_COPY_AND_ASSIGN(UpdateEngineClient);
 };

 class ExitingStatusUpdateHandler : public update_engine::StatusUpdateHandler {
  public:
   ~ExitingStatusUpdateHandler() override = default;

   void IPCError(const string& error) override;
 };

 void ExitingStatusUpdateHandler::IPCError(const string& error) {
   LOG(ERROR) << error;
   exit(1);
 }

 class WatchingStatusUpdateHandler : public ExitingStatusUpdateHandler {
  public:
   ~WatchingStatusUpdateHandler() override = default;

   void HandleStatusUpdate(int64_t last_checked_time,
                           double progress,
                           UpdateStatus current_operation,
                           const string& new_version,
                           int64_t new_size) override;
 };

 void WatchingStatusUpdateHandler::HandleStatusUpdate(
     int64_t last_checked_time, double progress, UpdateStatus 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: "
             << UpdateStatusToString(current_operation);
   LOG(INFO) << "  new_version: " << new_version;
   LOG(INFO) << "  new_size: " << new_size;
 }

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

   if (!client_->GetStatus(&last_checked_time, &progress, &current_op,
                           &new_version, &new_size)) {
     return false;
   }

   printf("LAST_CHECKED_TIME=%" PRIi64
          "\nPROGRESS=%f\nCURRENT_OP=%s\n"
          "NEW_VERSION=%s\nNEW_SIZE=%" PRIi64 "\n",
          last_checked_time, progress, UpdateStatusToString(current_op),
          new_version.c_str(), new_size);

   return true;
 }

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

   if (!client_->GetStatus(&last_checked_time, &progress, &current_op,
                           &new_version, &new_size)) {
     return 1;
   }

   if (current_op == UpdateStatus::UPDATED_NEED_REBOOT) {
     return 0;
   }

   return 2;
 }

 class UpdateWaitHandler : public ExitingStatusUpdateHandler {
  public:
   explicit UpdateWaitHandler(bool exit_on_error)
       : exit_on_error_(exit_on_error) {}

   ~UpdateWaitHandler() override = default;

   void HandleStatusUpdate(int64_t last_checked_time,
                           double progress,
                           UpdateStatus current_operation,
                           const string& new_version,
                           int64_t new_size) override;

  private:
   bool exit_on_error_;
 };

 void UpdateWaitHandler::HandleStatusUpdate(int64_t /* last_checked_time */,
                                            double /* progress */,
                                            UpdateStatus current_operation,
                                            const string& /* new_version */,
                                            int64_t /* new_size */) {
   if (exit_on_error_ && current_operation == UpdateStatus::IDLE) {
     LOG(ERROR) << "Update failed, current operations is "
                << UpdateStatusToString(current_operation);
     exit(1);
   }
   if (current_operation == UpdateStatus::UPDATED_NEED_REBOOT) {
     LOG(INFO) << "Update succeeded -- reboot needed.";
     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_);
   brillo::FlagHelper::Init(argc_, argv_, "Chromium OS Update Engine Client");

   // Ensure there are no positional arguments.
   const 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 ...";

     if (client_->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;)";
     } else {
       LOG(ERROR) << "ResetStatus failed";
       return 1;
     }
   }

   // 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 {
       if (!client_->SetUpdateOverCellularPermission(allowed)) {
         LOG(ERROR) << "Error setting the update over cellular setting.";
         return 1;
       }
     }
   }

   // Show the current update over cellular network setting.
   if (FLAGS_show_update_over_cellular) {
     bool allowed;

     if (!client_->GetUpdateOverCellularPermission(&allowed)) {
       LOG(ERROR) << "Error getting the update over cellular setting.";
       return 1;
     }

     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 {
       if (!client_->SetP2PUpdatePermission(enabled)) {
         LOG(ERROR) << "Error setting the peer-to-peer update setting.";
         return 1;
       }
     }
   }

   // Show the rollback availability.
   if (FLAGS_can_rollback) {
     string rollback_partition;

     if (!client_->GetRollbackPartition(&rollback_partition)) {
       LOG(ERROR) << "Error while querying rollback partition availabilty.";
       return 1;
     }

     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;

     if (!client_->GetP2PUpdatePermission(&enabled)) {
       LOG(ERROR) << "Error getting the peer-to-peer update setting.";
       return 1;
     }

     LOG(INFO) << "Current update using P2P setting: "
               << (enabled ? "ENABLED" : "DISABLED");
   }

   // First, update the target channel if requested.
   if (!FLAGS_channel.empty()) {
     if (!client_->SetTargetChannel(FLAGS_channel, FLAGS_powerwash)) {
       LOG(ERROR) << "Error setting the channel.";
       return 1;
     }

     LOG(INFO) << "Channel permanently set to: " << FLAGS_channel;
   }

   // Show the current and target channels if requested.
   if (FLAGS_show_channel) {
     string current_channel;
     string target_channel;

     if (!client_->GetChannel(&current_channel)) {
       LOG(ERROR) << "Error getting the current channel.";
       return 1;
     }

     if (!client_->GetTargetChannel(&target_channel)) {
       LOG(ERROR) << "Error getting the target channel.";
       return 1;
     }

     LOG(INFO) << "Current Channel: " << current_channel;

     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.";
     if (!client_->Rollback(FLAGS_powerwash)) {
       LOG(ERROR) << "Rollback request failed.";
       return 1;
     }
   }

   // 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.";
     if (!client_->AttemptUpdate(app_version, FLAGS_omaha_url,
                                 FLAGS_interactive)) {
       LOG(ERROR) << "Error checking for update.";
       return 1;
     }
   }

   // 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...";
     if (!ShowStatus()) {
       LOG(ERROR) << "Failed to query status";
       return 1;
     }
     return 0;
   }

   if (FLAGS_follow) {
     LOG(INFO) << "Waiting for update to complete.";
     auto handler = new UpdateWaitHandler(true);
     handlers_.emplace_back(handler);
     client_->RegisterStatusUpdateHandler(handler);
     return kContinueRunning;
   }

   if (FLAGS_watch_for_updates) {
     LOG(INFO) << "Watching for status updates.";
     auto handler = new WatchingStatusUpdateHandler();
     handlers_.emplace_back(handler);
     client_->RegisterStatusUpdateHandler(handler);
     return kContinueRunning;
   }

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

   if (FLAGS_prev_version) {
     string prev_version;

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

   if (FLAGS_is_reboot_needed) {
     int ret = GetNeedReboot();

     if (ret == 1) {
       LOG(ERROR) << "Could not query the current operation.";
     }

     return ret;
   }

   if (FLAGS_block_until_reboot_is_needed) {
     auto handler = new UpdateWaitHandler(false);
     handlers_.emplace_back(handler);
     client_->RegisterStatusUpdateHandler(handler);
     return kContinueRunning;
   }

   return 0;
 }

 void UpdateEngineClient::ProcessFlagsAndExit() {
   int ret = ProcessFlags();
   if (ret != kContinueRunning)
     QuitWithExitCode(ret);
 }

 }  // 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 <memory>
	#include <string>
	#include <vector>

	#include <base/bind.h>
	#include <base/command_line.h>
	#include <base/logging.h>
	#include <base/macros.h>
	#include <brillo/daemons/daemon.h>
	#include <brillo/flag_helper.h>

	#include "update_engine/client.h"
	#include "update_engine/status_update_handler.h"
	#include "update_engine/update_status.h"
	#include "update_engine/update_status_utils.h"

	using chromeos_update_engine::UpdateStatusToString;
	using std::string;
	using std::unique_ptr;
	using std::vector;
	using update_engine::UpdateStatus;

	namespace {

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

	class UpdateEngineClient : public brillo::Daemon {
	public:
	UpdateEngineClient(int argc, char** argv) : argc_(argc), argv_(argv) {
	}

	~UpdateEngineClient() override = default;

	protected:
	int OnInit() override {
	int ret = Daemon::OnInit();
	if (ret != EX_OK) return ret;

	client_ = update_engine::UpdateEngineClient::CreateInstance();

	if (!client_) {
	LOG(ERROR) << "UpdateEngineService not available.";
	return 1;
	}

	// We can't call QuitWithExitCode from OnInit(), so we delay the execution
	// of the ProcessFlags method after the Daemon initialization is done.
	base::MessageLoop::current()->PostTask(
	FROM_HERE,
	base::Bind(&UpdateEngineClient::ProcessFlagsAndExit,
	base::Unretained(this)));
	return EX_OK;
	}

	private:
	// Show the status of the update engine in stdout.
	bool ShowStatus();

	// Return whether we need to reboot. 0 if reboot is needed, 1 if an error
	// occurred, 2 if no reboot is needed.
	int GetNeedReboot();

	// Main method that parses and triggers all the actions based on the passed
	// flags. Returns the exit code of the program of kContinueRunning if it
	// should not exit.
	int ProcessFlags();

	// Processes the flags and exits the program accordingly.
	void ProcessFlagsAndExit();

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

	// Library-based client
	unique_ptr<update_engine::UpdateEngineClient> client_;

	// Pointers to handlers for cleanup
	vector<unique_ptr<update_engine::StatusUpdateHandler>> handlers_;

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

	DISALLOW_COPY_AND_ASSIGN(UpdateEngineClient);
	};

	class ExitingStatusUpdateHandler : public update_engine::StatusUpdateHandler {
	public:
	~ExitingStatusUpdateHandler() override = default;

	void IPCError(const string& error) override;
	};

	void ExitingStatusUpdateHandler::IPCError(const string& error) {
	LOG(ERROR) << error;
	exit(1);
	}

	class WatchingStatusUpdateHandler : public ExitingStatusUpdateHandler {
	public:
	~WatchingStatusUpdateHandler() override = default;

	void HandleStatusUpdate(int64_t last_checked_time,
	double progress,
	UpdateStatus current_operation,
	const string& new_version,
	int64_t new_size) override;
	};

	void WatchingStatusUpdateHandler::HandleStatusUpdate(
	int64_t last_checked_time, double progress, UpdateStatus 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: "
	<< UpdateStatusToString(current_operation);
	LOG(INFO) << " new_version: " << new_version;
	LOG(INFO) << " new_size: " << new_size;
	}

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

	if (!client_->GetStatus(&last_checked_time, &progress, &current_op,
	&new_version, &new_size)) {
	return false;
	}

	printf("LAST_CHECKED_TIME=%" PRIi64
	"\nPROGRESS=%f\nCURRENT_OP=%s\n"
	"NEW_VERSION=%s\nNEW_SIZE=%" PRIi64 "\n",
	last_checked_time, progress, UpdateStatusToString(current_op),
	new_version.c_str(), new_size);

	return true;
	}

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

	if (!client_->GetStatus(&last_checked_time, &progress, &current_op,
	&new_version, &new_size)) {
	return 1;
	}

	if (current_op == UpdateStatus::UPDATED_NEED_REBOOT) {
	return 0;
	}

	return 2;
	}

	class UpdateWaitHandler : public ExitingStatusUpdateHandler {
	public:
	explicit UpdateWaitHandler(bool exit_on_error)
	: exit_on_error_(exit_on_error) {}

	~UpdateWaitHandler() override = default;

	void HandleStatusUpdate(int64_t last_checked_time,
	double progress,
	UpdateStatus current_operation,
	const string& new_version,
	int64_t new_size) override;

	private:
	bool exit_on_error_;
	};

	void UpdateWaitHandler::HandleStatusUpdate(int64_t /* last_checked_time */,
	double /* progress */,
	UpdateStatus current_operation,
	const string& /* new_version */,
	int64_t /* new_size */) {
	if (exit_on_error_ && current_operation == UpdateStatus::IDLE) {
	LOG(ERROR) << "Update failed, current operations is "
	<< UpdateStatusToString(current_operation);
	exit(1);
	}
	if (current_operation == UpdateStatus::UPDATED_NEED_REBOOT) {
	LOG(INFO) << "Update succeeded -- reboot needed.";
	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_);
	brillo::FlagHelper::Init(argc_, argv_, "Chromium OS Update Engine Client");

	// Ensure there are no positional arguments.
	const 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 ...";

	if (client_->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;)";
	} else {
	LOG(ERROR) << "ResetStatus failed";
	return 1;
	}
	}

	// 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 {
	if (!client_->SetUpdateOverCellularPermission(allowed)) {
	LOG(ERROR) << "Error setting the update over cellular setting.";
	return 1;
	}
	}
	}

	// Show the current update over cellular network setting.
	if (FLAGS_show_update_over_cellular) {
	bool allowed;

	if (!client_->GetUpdateOverCellularPermission(&allowed)) {
	LOG(ERROR) << "Error getting the update over cellular setting.";
	return 1;
	}

	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 {
	if (!client_->SetP2PUpdatePermission(enabled)) {
	LOG(ERROR) << "Error setting the peer-to-peer update setting.";
	return 1;
	}
	}
	}

	// Show the rollback availability.
	if (FLAGS_can_rollback) {
	string rollback_partition;

	if (!client_->GetRollbackPartition(&rollback_partition)) {
	LOG(ERROR) << "Error while querying rollback partition availabilty.";
	return 1;
	}

	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;

	if (!client_->GetP2PUpdatePermission(&enabled)) {
	LOG(ERROR) << "Error getting the peer-to-peer update setting.";
	return 1;
	}

	LOG(INFO) << "Current update using P2P setting: "
	<< (enabled ? "ENABLED" : "DISABLED");
	}

	// First, update the target channel if requested.
	if (!FLAGS_channel.empty()) {
	if (!client_->SetTargetChannel(FLAGS_channel, FLAGS_powerwash)) {
	LOG(ERROR) << "Error setting the channel.";
	return 1;
	}

	LOG(INFO) << "Channel permanently set to: " << FLAGS_channel;
	}

	// Show the current and target channels if requested.
	if (FLAGS_show_channel) {
	string current_channel;
	string target_channel;

	if (!client_->GetChannel(&current_channel)) {
	LOG(ERROR) << "Error getting the current channel.";
	return 1;
	}

	if (!client_->GetTargetChannel(&target_channel)) {
	LOG(ERROR) << "Error getting the target channel.";
	return 1;
	}

	LOG(INFO) << "Current Channel: " << current_channel;

	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.";
	if (!client_->Rollback(FLAGS_powerwash)) {
	LOG(ERROR) << "Rollback request failed.";
	return 1;
	}
	}

	// 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.";
	if (!client_->AttemptUpdate(app_version, FLAGS_omaha_url,
	FLAGS_interactive)) {
	LOG(ERROR) << "Error checking for update.";
	return 1;
	}
	}

	// 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...";
	if (!ShowStatus()) {
	LOG(ERROR) << "Failed to query status";
	return 1;
	}
	return 0;
	}

	if (FLAGS_follow) {
	LOG(INFO) << "Waiting for update to complete.";
	auto handler = new UpdateWaitHandler(true);
	handlers_.emplace_back(handler);
	client_->RegisterStatusUpdateHandler(handler);
	return kContinueRunning;
	}

	if (FLAGS_watch_for_updates) {
	LOG(INFO) << "Watching for status updates.";
	auto handler = new WatchingStatusUpdateHandler();
	handlers_.emplace_back(handler);
	client_->RegisterStatusUpdateHandler(handler);
	return kContinueRunning;
	}

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

	if (FLAGS_prev_version) {
	string prev_version;

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

	if (FLAGS_is_reboot_needed) {
	int ret = GetNeedReboot();

	if (ret == 1) {
	LOG(ERROR) << "Could not query the current operation.";
	}

	return ret;
	}

	if (FLAGS_block_until_reboot_is_needed) {
	auto handler = new UpdateWaitHandler(false);
	handlers_.emplace_back(handler);
	client_->RegisterStatusUpdateHandler(handler);
	return kContinueRunning;
	}

	return 0;
	}

	void UpdateEngineClient::ProcessFlagsAndExit() {
	int ret = ProcessFlags();
	if (ret != kContinueRunning)
	QuitWithExitCode(ret);
	}

	} // namespace

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