common_service.cc - SHIFTPHONES/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 "update_engine/common_service.h"

 #include <set>
 #include <string>

 #include <base/bind.h>
 #include <base/location.h>
 #include <base/logging.h>
 #include <base/strings/stringprintf.h>
 #include <brillo/message_loops/message_loop.h>
 #include <brillo/strings/string_utils.h>
 #include <policy/device_policy.h>

 #include "update_engine/common/clock_interface.h"
 #include "update_engine/common/hardware_interface.h"
 #include "update_engine/common/prefs.h"
 #include "update_engine/common/utils.h"
 #include "update_engine/connection_manager_interface.h"
 #include "update_engine/omaha_request_params.h"
 #include "update_engine/omaha_utils.h"
 #include "update_engine/p2p_manager.h"
 #include "update_engine/payload_state_interface.h"
 #include "update_engine/update_attempter.h"

 using base::StringPrintf;
 using brillo::ErrorPtr;
 using brillo::string_utils::ToString;
 using std::set;
 using std::string;
 using update_engine::UpdateAttemptFlags;
 using update_engine::UpdateEngineStatus;

 namespace chromeos_update_engine {

 namespace {
 // Log and set the error on the passed ErrorPtr.
 void LogAndSetError(ErrorPtr* error,
                     const tracked_objects::Location& location,
                     const string& reason) {
   brillo::Error::AddTo(error,
                        location,
                        UpdateEngineService::kErrorDomain,
                        UpdateEngineService::kErrorFailed,
                        reason);
   LOG(ERROR) << "Sending Update Engine Failure: " << location.ToString() << ": "
              << reason;
 }
 }  // namespace

 const char* const UpdateEngineService::kErrorDomain = "update_engine";
 const char* const UpdateEngineService::kErrorFailed =
     "org.chromium.UpdateEngine.Error.Failed";

 UpdateEngineService::UpdateEngineService(SystemState* system_state)
     : system_state_(system_state) {
 }

 // org::chromium::UpdateEngineInterfaceInterface methods implementation.

 bool UpdateEngineService::SetUpdateAttemptFlags(ErrorPtr* /* error */,
                                                 int32_t in_flags_as_int) {
   auto flags = static_cast<UpdateAttemptFlags>(in_flags_as_int);
   LOG(INFO) << "Setting Update Attempt Flags: "
             << "flags=0x" << std::hex << flags << " "
             << "RestrictDownload="
             << ((flags & UpdateAttemptFlags::kFlagRestrictDownload) ? "yes"
                                                                     : "no");
   system_state_->update_attempter()->SetUpdateAttemptFlags(flags);
   return true;
 }

 bool UpdateEngineService::AttemptUpdate(ErrorPtr* /* error */,
                                         const string& in_app_version,
                                         const string& in_omaha_url,
                                         int32_t in_flags_as_int,
                                         bool* out_result) {
   auto flags = static_cast<UpdateAttemptFlags>(in_flags_as_int);
   bool interactive = !(flags & UpdateAttemptFlags::kFlagNonInteractive);
   bool restrict_downloads = (flags & UpdateAttemptFlags::kFlagRestrictDownload);

   LOG(INFO) << "Attempt update: app_version=\"" << in_app_version << "\" "
             << "omaha_url=\"" << in_omaha_url << "\" "
             << "flags=0x" << std::hex << flags << " "
             << "interactive=" << (interactive ? "yes " : "no ")
             << "RestrictDownload=" << (restrict_downloads ? "yes " : "no ");

   *out_result = system_state_->update_attempter()->CheckForUpdate(
       in_app_version, in_omaha_url, flags);
   return true;
 }

 bool UpdateEngineService::AttemptRollback(ErrorPtr* error, bool in_powerwash) {
   LOG(INFO) << "Attempting rollback to non-active partitions.";

   if (!system_state_->update_attempter()->Rollback(in_powerwash)) {
     // TODO(dgarrett): Give a more specific error code/reason.
     LogAndSetError(error, FROM_HERE, "Rollback attempt failed.");
     return false;
   }
   return true;
 }

 bool UpdateEngineService::CanRollback(ErrorPtr* /* error */,
                                       bool* out_can_rollback) {
   bool can_rollback = system_state_->update_attempter()->CanRollback();
   LOG(INFO) << "Checking to see if we can rollback . Result: " << can_rollback;
   *out_can_rollback = can_rollback;
   return true;
 }

 bool UpdateEngineService::ResetStatus(ErrorPtr* error) {
   if (!system_state_->update_attempter()->ResetStatus()) {
     // TODO(dgarrett): Give a more specific error code/reason.
     LogAndSetError(error, FROM_HERE, "ResetStatus failed.");
     return false;
   }
   return true;
 }

 bool UpdateEngineService::GetStatus(ErrorPtr* error,
                                     UpdateEngineStatus* out_status) {
   if (!system_state_->update_attempter()->GetStatus(out_status)) {
     LogAndSetError(error, FROM_HERE, "GetStatus failed.");
     return false;
   }
   return true;
 }

 bool UpdateEngineService::RebootIfNeeded(ErrorPtr* error) {
   if (!system_state_->update_attempter()->RebootIfNeeded()) {
     // TODO(dgarrett): Give a more specific error code/reason.
     LogAndSetError(error, FROM_HERE, "Reboot not needed, or attempt failed.");
     return false;
   }
   return true;
 }

 bool UpdateEngineService::SetChannel(ErrorPtr* error,
                                      const string& in_target_channel,
                                      bool in_is_powerwash_allowed) {
   const policy::DevicePolicy* device_policy = system_state_->device_policy();

   // The device_policy is loaded in a lazy way before an update check. Load it
   // now from the libbrillo cache if it wasn't already loaded.
   if (!device_policy) {
     UpdateAttempter* update_attempter = system_state_->update_attempter();
     if (update_attempter) {
       update_attempter->RefreshDevicePolicy();
       device_policy = system_state_->device_policy();
     }
   }

   bool delegated = false;
   if (device_policy && device_policy->GetReleaseChannelDelegated(&delegated) &&
       !delegated) {
     LogAndSetError(error,
                    FROM_HERE,
                    "Cannot set target channel explicitly when channel "
                    "policy/settings is not delegated");
     return false;
   }

   LOG(INFO) << "Setting destination channel to: " << in_target_channel;
   string error_message;
   if (!system_state_->request_params()->SetTargetChannel(
           in_target_channel, in_is_powerwash_allowed, &error_message)) {
     LogAndSetError(error, FROM_HERE, error_message);
     return false;
   }
   return true;
 }

 bool UpdateEngineService::GetChannel(ErrorPtr* /* error */,
                                      bool in_get_current_channel,
                                      string* out_channel) {
   OmahaRequestParams* rp = system_state_->request_params();
   *out_channel =
       (in_get_current_channel ? rp->current_channel() : rp->target_channel());
   return true;
 }

 bool UpdateEngineService::SetCohortHint(ErrorPtr* error,
                                         string in_cohort_hint) {
   PrefsInterface* prefs = system_state_->prefs();

   // It is ok to override the cohort hint with an invalid value since it is
   // stored in stateful partition. The code reading it should sanitize it
   // anyway.
   if (!prefs->SetString(kPrefsOmahaCohortHint, in_cohort_hint)) {
     LogAndSetError(
         error,
         FROM_HERE,
         StringPrintf("Error setting the cohort hint value to \"%s\".",
                      in_cohort_hint.c_str()));
     return false;
   }
   return true;
 }

 bool UpdateEngineService::GetCohortHint(ErrorPtr* error,
                                         string* out_cohort_hint) {
   PrefsInterface* prefs = system_state_->prefs();

   *out_cohort_hint = "";
   if (prefs->Exists(kPrefsOmahaCohortHint) &&
       !prefs->GetString(kPrefsOmahaCohortHint, out_cohort_hint)) {
     LogAndSetError(error, FROM_HERE, "Error getting the cohort hint.");
     return false;
   }
   return true;
 }

 bool UpdateEngineService::SetP2PUpdatePermission(ErrorPtr* error,
                                                  bool in_enabled) {
   PrefsInterface* prefs = system_state_->prefs();

   if (!prefs->SetBoolean(kPrefsP2PEnabled, in_enabled)) {
     LogAndSetError(
         error,
         FROM_HERE,
         StringPrintf("Error setting the update via p2p permission to %s.",
                      ToString(in_enabled).c_str()));
     return false;
   }
   return true;
 }

 bool UpdateEngineService::GetP2PUpdatePermission(ErrorPtr* error,
                                                  bool* out_enabled) {
   PrefsInterface* prefs = system_state_->prefs();

   bool p2p_pref = false;  // Default if no setting is present.
   if (prefs->Exists(kPrefsP2PEnabled) &&
       !prefs->GetBoolean(kPrefsP2PEnabled, &p2p_pref)) {
     LogAndSetError(error, FROM_HERE, "Error getting the P2PEnabled setting.");
     return false;
   }

   *out_enabled = p2p_pref;
   return true;
 }

 bool UpdateEngineService::SetUpdateOverCellularPermission(ErrorPtr* error,
                                                           bool in_allowed) {
   set<string> allowed_types;
   const policy::DevicePolicy* device_policy = system_state_->device_policy();

   // The device_policy is loaded in a lazy way before an update check. Load it
   // now from the libbrillo cache if it wasn't already loaded.
   if (!device_policy) {
     UpdateAttempter* update_attempter = system_state_->update_attempter();
     if (update_attempter) {
       update_attempter->RefreshDevicePolicy();
       device_policy = system_state_->device_policy();
     }
   }

   // Check if this setting is allowed by the device policy.
   if (device_policy &&
       device_policy->GetAllowedConnectionTypesForUpdate(&allowed_types)) {
     LogAndSetError(error,
                    FROM_HERE,
                    "Ignoring the update over cellular setting since there's "
                    "a device policy enforcing this setting.");
     return false;
   }

   // If the policy wasn't loaded yet, then it is still OK to change the local
   // setting because the policy will be checked again during the update check.

   PrefsInterface* prefs = system_state_->prefs();

   if (!prefs->SetBoolean(kPrefsUpdateOverCellularPermission, in_allowed)) {
     LogAndSetError(error,
                    FROM_HERE,
                    string("Error setting the update over cellular to ") +
                        (in_allowed ? "true" : "false"));
     return false;
   }
   return true;
 }

 bool UpdateEngineService::GetUpdateOverCellularPermission(ErrorPtr* /* error */,
                                                           bool* out_allowed) {
   ConnectionManagerInterface* cm = system_state_->connection_manager();

   // The device_policy is loaded in a lazy way before an update check and is
   // used to determine if an update is allowed over cellular. Load the device
   // policy now from the libbrillo cache if it wasn't already loaded.
   if (!system_state_->device_policy()) {
     UpdateAttempter* update_attempter = system_state_->update_attempter();
     if (update_attempter)
       update_attempter->RefreshDevicePolicy();
   }

   // Return the current setting based on the same logic used while checking for
   // updates. A log message could be printed as the result of this test.
   LOG(INFO) << "Checking if updates over cellular networks are allowed:";
   *out_allowed = cm->IsUpdateAllowedOver(ConnectionType::kCellular,
                                          ConnectionTethering::kUnknown);
   return true;
 }

 bool UpdateEngineService::GetDurationSinceUpdate(ErrorPtr* error,
                                                  int64_t* out_usec_wallclock) {
   base::Time time;
   if (!system_state_->update_attempter()->GetBootTimeAtUpdate(&time)) {
     LogAndSetError(error, FROM_HERE, "No pending update.");
     return false;
   }

   ClockInterface* clock = system_state_->clock();
   *out_usec_wallclock = (clock->GetBootTime() - time).InMicroseconds();
   return true;
 }

 bool UpdateEngineService::GetPrevVersion(ErrorPtr* /* error */,
                                          string* out_prev_version) {
   *out_prev_version = system_state_->update_attempter()->GetPrevVersion();
   return true;
 }

 bool UpdateEngineService::GetRollbackPartition(
     ErrorPtr* /* error */, string* out_rollback_partition_name) {
   BootControlInterface::Slot rollback_slot =
       system_state_->update_attempter()->GetRollbackSlot();

   if (rollback_slot == BootControlInterface::kInvalidSlot) {
     out_rollback_partition_name->clear();
     return true;
   }

   string name;
   if (!system_state_->boot_control()->GetPartitionDevice(
           "KERNEL", rollback_slot, &name)) {
     LOG(ERROR) << "Invalid rollback device";
     return false;
   }

   LOG(INFO) << "Getting rollback partition name. Result: " << name;
   *out_rollback_partition_name = name;
   return true;
 }

 bool UpdateEngineService::GetLastAttemptError(ErrorPtr* /* error */,
                                               int32_t* out_last_attempt_error) {
   ErrorCode error_code = system_state_->payload_state()->GetAttemptErrorCode();
   *out_last_attempt_error = static_cast<int>(error_code);
   return true;
 }

 bool UpdateEngineService::GetEolStatus(ErrorPtr* error,
                                        int32_t* out_eol_status) {
   PrefsInterface* prefs = system_state_->prefs();

   string str_eol_status;
   if (prefs->Exists(kPrefsOmahaEolStatus) &&
       !prefs->GetString(kPrefsOmahaEolStatus, &str_eol_status)) {
     LogAndSetError(error, FROM_HERE, "Error getting the end-of-life status.");
     return false;
   }

   // StringToEolStatus will return kSupported for invalid values.
   *out_eol_status = static_cast<int32_t>(StringToEolStatus(str_eol_status));
   return true;
 }

 }  // namespace chromeos_update_engine
	//
	// 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 "update_engine/common_service.h"

	#include <set>
	#include <string>

	#include <base/bind.h>
	#include <base/location.h>
	#include <base/logging.h>
	#include <base/strings/stringprintf.h>
	#include <brillo/message_loops/message_loop.h>
	#include <brillo/strings/string_utils.h>
	#include <policy/device_policy.h>

	#include "update_engine/common/clock_interface.h"
	#include "update_engine/common/hardware_interface.h"
	#include "update_engine/common/prefs.h"
	#include "update_engine/common/utils.h"
	#include "update_engine/connection_manager_interface.h"
	#include "update_engine/omaha_request_params.h"
	#include "update_engine/omaha_utils.h"
	#include "update_engine/p2p_manager.h"
	#include "update_engine/payload_state_interface.h"
	#include "update_engine/update_attempter.h"

	using base::StringPrintf;
	using brillo::ErrorPtr;
	using brillo::string_utils::ToString;
	using std::set;
	using std::string;
	using update_engine::UpdateAttemptFlags;
	using update_engine::UpdateEngineStatus;

	namespace chromeos_update_engine {

	namespace {
	// Log and set the error on the passed ErrorPtr.
	void LogAndSetError(ErrorPtr* error,
	const tracked_objects::Location& location,
	const string& reason) {
	brillo::Error::AddTo(error,
	location,
	UpdateEngineService::kErrorDomain,
	UpdateEngineService::kErrorFailed,
	reason);
	LOG(ERROR) << "Sending Update Engine Failure: " << location.ToString() << ": "
	<< reason;
	}
	} // namespace

	const char* const UpdateEngineService::kErrorDomain = "update_engine";
	const char* const UpdateEngineService::kErrorFailed =
	"org.chromium.UpdateEngine.Error.Failed";

	UpdateEngineService::UpdateEngineService(SystemState* system_state)
	: system_state_(system_state) {
	}

	// org::chromium::UpdateEngineInterfaceInterface methods implementation.

	bool UpdateEngineService::SetUpdateAttemptFlags(ErrorPtr* /* error */,
	int32_t in_flags_as_int) {
	auto flags = static_cast<UpdateAttemptFlags>(in_flags_as_int);
	LOG(INFO) << "Setting Update Attempt Flags: "
	<< "flags=0x" << std::hex << flags << " "
	<< "RestrictDownload="
	<< ((flags & UpdateAttemptFlags::kFlagRestrictDownload) ? "yes"
	: "no");
	system_state_->update_attempter()->SetUpdateAttemptFlags(flags);
	return true;
	}

	bool UpdateEngineService::AttemptUpdate(ErrorPtr* /* error */,
	const string& in_app_version,
	const string& in_omaha_url,
	int32_t in_flags_as_int,
	bool* out_result) {
	auto flags = static_cast<UpdateAttemptFlags>(in_flags_as_int);
	bool interactive = !(flags & UpdateAttemptFlags::kFlagNonInteractive);
	bool restrict_downloads = (flags & UpdateAttemptFlags::kFlagRestrictDownload);

	LOG(INFO) << "Attempt update: app_version=\"" << in_app_version << "\" "
	<< "omaha_url=\"" << in_omaha_url << "\" "
	<< "flags=0x" << std::hex << flags << " "
	<< "interactive=" << (interactive ? "yes " : "no ")
	<< "RestrictDownload=" << (restrict_downloads ? "yes " : "no ");

	*out_result = system_state_->update_attempter()->CheckForUpdate(
	in_app_version, in_omaha_url, flags);
	return true;
	}

	bool UpdateEngineService::AttemptRollback(ErrorPtr* error, bool in_powerwash) {
	LOG(INFO) << "Attempting rollback to non-active partitions.";

	if (!system_state_->update_attempter()->Rollback(in_powerwash)) {
	// TODO(dgarrett): Give a more specific error code/reason.
	LogAndSetError(error, FROM_HERE, "Rollback attempt failed.");
	return false;
	}
	return true;
	}

	bool UpdateEngineService::CanRollback(ErrorPtr* /* error */,
	bool* out_can_rollback) {
	bool can_rollback = system_state_->update_attempter()->CanRollback();
	LOG(INFO) << "Checking to see if we can rollback . Result: " << can_rollback;
	*out_can_rollback = can_rollback;
	return true;
	}

	bool UpdateEngineService::ResetStatus(ErrorPtr* error) {
	if (!system_state_->update_attempter()->ResetStatus()) {
	// TODO(dgarrett): Give a more specific error code/reason.
	LogAndSetError(error, FROM_HERE, "ResetStatus failed.");
	return false;
	}
	return true;
	}

	bool UpdateEngineService::GetStatus(ErrorPtr* error,
	UpdateEngineStatus* out_status) {
	if (!system_state_->update_attempter()->GetStatus(out_status)) {
	LogAndSetError(error, FROM_HERE, "GetStatus failed.");
	return false;
	}
	return true;
	}

	bool UpdateEngineService::RebootIfNeeded(ErrorPtr* error) {
	if (!system_state_->update_attempter()->RebootIfNeeded()) {
	// TODO(dgarrett): Give a more specific error code/reason.
	LogAndSetError(error, FROM_HERE, "Reboot not needed, or attempt failed.");
	return false;
	}
	return true;
	}

	bool UpdateEngineService::SetChannel(ErrorPtr* error,
	const string& in_target_channel,
	bool in_is_powerwash_allowed) {
	const policy::DevicePolicy* device_policy = system_state_->device_policy();

	// The device_policy is loaded in a lazy way before an update check. Load it
	// now from the libbrillo cache if it wasn't already loaded.
	if (!device_policy) {
	UpdateAttempter* update_attempter = system_state_->update_attempter();
	if (update_attempter) {
	update_attempter->RefreshDevicePolicy();
	device_policy = system_state_->device_policy();
	}
	}

	bool delegated = false;
	if (device_policy && device_policy->GetReleaseChannelDelegated(&delegated) &&
	!delegated) {
	LogAndSetError(error,
	FROM_HERE,
	"Cannot set target channel explicitly when channel "
	"policy/settings is not delegated");
	return false;
	}

	LOG(INFO) << "Setting destination channel to: " << in_target_channel;
	string error_message;
	if (!system_state_->request_params()->SetTargetChannel(
	in_target_channel, in_is_powerwash_allowed, &error_message)) {
	LogAndSetError(error, FROM_HERE, error_message);
	return false;
	}
	return true;
	}

	bool UpdateEngineService::GetChannel(ErrorPtr* /* error */,
	bool in_get_current_channel,
	string* out_channel) {
	OmahaRequestParams* rp = system_state_->request_params();
	*out_channel =
	(in_get_current_channel ? rp->current_channel() : rp->target_channel());
	return true;
	}

	bool UpdateEngineService::SetCohortHint(ErrorPtr* error,
	string in_cohort_hint) {
	PrefsInterface* prefs = system_state_->prefs();

	// It is ok to override the cohort hint with an invalid value since it is
	// stored in stateful partition. The code reading it should sanitize it
	// anyway.
	if (!prefs->SetString(kPrefsOmahaCohortHint, in_cohort_hint)) {
	LogAndSetError(
	error,
	FROM_HERE,
	StringPrintf("Error setting the cohort hint value to \"%s\".",
	in_cohort_hint.c_str()));
	return false;
	}
	return true;
	}

	bool UpdateEngineService::GetCohortHint(ErrorPtr* error,
	string* out_cohort_hint) {
	PrefsInterface* prefs = system_state_->prefs();

	*out_cohort_hint = "";
	if (prefs->Exists(kPrefsOmahaCohortHint) &&
	!prefs->GetString(kPrefsOmahaCohortHint, out_cohort_hint)) {
	LogAndSetError(error, FROM_HERE, "Error getting the cohort hint.");
	return false;
	}
	return true;
	}

	bool UpdateEngineService::SetP2PUpdatePermission(ErrorPtr* error,
	bool in_enabled) {
	PrefsInterface* prefs = system_state_->prefs();

	if (!prefs->SetBoolean(kPrefsP2PEnabled, in_enabled)) {
	LogAndSetError(
	error,
	FROM_HERE,
	StringPrintf("Error setting the update via p2p permission to %s.",
	ToString(in_enabled).c_str()));
	return false;
	}
	return true;
	}

	bool UpdateEngineService::GetP2PUpdatePermission(ErrorPtr* error,
	bool* out_enabled) {
	PrefsInterface* prefs = system_state_->prefs();

	bool p2p_pref = false; // Default if no setting is present.
	if (prefs->Exists(kPrefsP2PEnabled) &&
	!prefs->GetBoolean(kPrefsP2PEnabled, &p2p_pref)) {
	LogAndSetError(error, FROM_HERE, "Error getting the P2PEnabled setting.");
	return false;
	}

	*out_enabled = p2p_pref;
	return true;
	}

	bool UpdateEngineService::SetUpdateOverCellularPermission(ErrorPtr* error,
	bool in_allowed) {
	set<string> allowed_types;
	const policy::DevicePolicy* device_policy = system_state_->device_policy();

	// The device_policy is loaded in a lazy way before an update check. Load it
	// now from the libbrillo cache if it wasn't already loaded.
	if (!device_policy) {
	UpdateAttempter* update_attempter = system_state_->update_attempter();
	if (update_attempter) {
	update_attempter->RefreshDevicePolicy();
	device_policy = system_state_->device_policy();
	}
	}

	// Check if this setting is allowed by the device policy.
	if (device_policy &&
	device_policy->GetAllowedConnectionTypesForUpdate(&allowed_types)) {
	LogAndSetError(error,
	FROM_HERE,
	"Ignoring the update over cellular setting since there's "
	"a device policy enforcing this setting.");
	return false;
	}

	// If the policy wasn't loaded yet, then it is still OK to change the local
	// setting because the policy will be checked again during the update check.

	PrefsInterface* prefs = system_state_->prefs();

	if (!prefs->SetBoolean(kPrefsUpdateOverCellularPermission, in_allowed)) {
	LogAndSetError(error,
	FROM_HERE,
	string("Error setting the update over cellular to ") +
	(in_allowed ? "true" : "false"));
	return false;
	}
	return true;
	}

	bool UpdateEngineService::GetUpdateOverCellularPermission(ErrorPtr* /* error */,
	bool* out_allowed) {
	ConnectionManagerInterface* cm = system_state_->connection_manager();

	// The device_policy is loaded in a lazy way before an update check and is
	// used to determine if an update is allowed over cellular. Load the device
	// policy now from the libbrillo cache if it wasn't already loaded.
	if (!system_state_->device_policy()) {
	UpdateAttempter* update_attempter = system_state_->update_attempter();
	if (update_attempter)
	update_attempter->RefreshDevicePolicy();
	}

	// Return the current setting based on the same logic used while checking for
	// updates. A log message could be printed as the result of this test.
	LOG(INFO) << "Checking if updates over cellular networks are allowed:";
	*out_allowed = cm->IsUpdateAllowedOver(ConnectionType::kCellular,
	ConnectionTethering::kUnknown);
	return true;
	}

	bool UpdateEngineService::GetDurationSinceUpdate(ErrorPtr* error,
	int64_t* out_usec_wallclock) {
	base::Time time;
	if (!system_state_->update_attempter()->GetBootTimeAtUpdate(&time)) {
	LogAndSetError(error, FROM_HERE, "No pending update.");
	return false;
	}

	ClockInterface* clock = system_state_->clock();
	*out_usec_wallclock = (clock->GetBootTime() - time).InMicroseconds();
	return true;
	}

	bool UpdateEngineService::GetPrevVersion(ErrorPtr* /* error */,
	string* out_prev_version) {
	*out_prev_version = system_state_->update_attempter()->GetPrevVersion();
	return true;
	}

	bool UpdateEngineService::GetRollbackPartition(
	ErrorPtr* /* error /, string out_rollback_partition_name) {
	BootControlInterface::Slot rollback_slot =
	system_state_->update_attempter()->GetRollbackSlot();

	if (rollback_slot == BootControlInterface::kInvalidSlot) {
	out_rollback_partition_name->clear();
	return true;
	}

	string name;
	if (!system_state_->boot_control()->GetPartitionDevice(
	"KERNEL", rollback_slot, &name)) {
	LOG(ERROR) << "Invalid rollback device";
	return false;
	}

	LOG(INFO) << "Getting rollback partition name. Result: " << name;
	*out_rollback_partition_name = name;
	return true;
	}

	bool UpdateEngineService::GetLastAttemptError(ErrorPtr* /* error */,
	int32_t* out_last_attempt_error) {
	ErrorCode error_code = system_state_->payload_state()->GetAttemptErrorCode();
	*out_last_attempt_error = static_cast<int>(error_code);
	return true;
	}

	bool UpdateEngineService::GetEolStatus(ErrorPtr* error,
	int32_t* out_eol_status) {
	PrefsInterface* prefs = system_state_->prefs();

	string str_eol_status;
	if (prefs->Exists(kPrefsOmahaEolStatus) &&
	!prefs->GetString(kPrefsOmahaEolStatus, &str_eol_status)) {
	LogAndSetError(error, FROM_HERE, "Error getting the end-of-life status.");
	return false;
	}

	// StringToEolStatus will return kSupported for invalid values.
	*out_eol_status = static_cast<int32_t>(StringToEolStatus(str_eol_status));
	return true;
	}

	} // namespace chromeos_update_engine