boot_control_android.cc - SHIFTPHONES/android_system_update_engine - Gitiles

 //
 // Copyright (C) 2015 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/boot_control_android.h"

 #include <memory>
 #include <utility>
 #include <vector>

 #include <base/bind.h>
 #include <base/logging.h>
 #include <base/strings/string_util.h>
 #include <bootloader_message/bootloader_message.h>
 #include <brillo/message_loops/message_loop.h>
 #include <fs_mgr.h>
 #include <fs_mgr_overlayfs.h>

 #include "update_engine/common/utils.h"
 #include "update_engine/dynamic_partition_control_android.h"

 using std::string;

 using android::dm::DmDeviceState;
 using android::fs_mgr::Partition;
 using android::hardware::hidl_string;
 using android::hardware::Return;
 using android::hardware::boot::V1_0::BoolResult;
 using android::hardware::boot::V1_0::CommandResult;
 using android::hardware::boot::V1_0::IBootControl;
 using Slot = chromeos_update_engine::BootControlInterface::Slot;
 using PartitionMetadata =
     chromeos_update_engine::BootControlInterface::PartitionMetadata;

 namespace {

 auto StoreResultCallback(CommandResult* dest) {
   return [dest](const CommandResult& result) { *dest = result; };
 }
 }  // namespace

 namespace chromeos_update_engine {

 namespace boot_control {

 // Factory defined in boot_control.h.
 std::unique_ptr<BootControlInterface> CreateBootControl() {
   auto boot_control = std::make_unique<BootControlAndroid>();
   if (!boot_control->Init()) {
     return nullptr;
   }
   return std::move(boot_control);
 }

 }  // namespace boot_control

 bool BootControlAndroid::Init() {
   module_ = IBootControl::getService();
   if (module_ == nullptr) {
     LOG(ERROR) << "Error getting bootctrl HIDL module.";
     return false;
   }

   LOG(INFO) << "Loaded boot control hidl hal.";

   dynamic_control_ = std::make_unique<DynamicPartitionControlAndroid>();

   return true;
 }

 void BootControlAndroid::Cleanup() {
   dynamic_control_->Cleanup();
 }

 unsigned int BootControlAndroid::GetNumSlots() const {
   return module_->getNumberSlots();
 }

 BootControlInterface::Slot BootControlAndroid::GetCurrentSlot() const {
   return module_->getCurrentSlot();
 }

 bool BootControlAndroid::GetSuffix(Slot slot, string* suffix) const {
   auto store_suffix_cb = [&suffix](hidl_string cb_suffix) {
     *suffix = cb_suffix.c_str();
   };
   Return<void> ret = module_->getSuffix(slot, store_suffix_cb);

   if (!ret.isOk()) {
     LOG(ERROR) << "boot_control impl returned no suffix for slot "
                << SlotName(slot);
     return false;
   }
   return true;
 }

 bool BootControlAndroid::IsSuperBlockDevice(
     const base::FilePath& device_dir,
     Slot slot,
     const string& partition_name_suffix) const {
   string source_device =
       device_dir.Append(fs_mgr_get_super_partition_name(slot)).value();
   auto source_metadata = dynamic_control_->LoadMetadataBuilder(
       source_device, slot, BootControlInterface::kInvalidSlot);
   return source_metadata->HasBlockDevice(partition_name_suffix);
 }

 BootControlAndroid::DynamicPartitionDeviceStatus
 BootControlAndroid::GetDynamicPartitionDevice(
     const base::FilePath& device_dir,
     const string& partition_name_suffix,
     Slot slot,
     string* device) const {
   string super_device =
       device_dir.Append(fs_mgr_get_super_partition_name(slot)).value();

   auto builder = dynamic_control_->LoadMetadataBuilder(
       super_device, slot, BootControlInterface::kInvalidSlot);

   if (builder == nullptr) {
     LOG(ERROR) << "No metadata in slot "
                << BootControlInterface::SlotName(slot);
     return DynamicPartitionDeviceStatus::ERROR;
   }

   Slot current_slot = GetCurrentSlot();
   if (builder->FindPartition(partition_name_suffix) == nullptr) {
     LOG(INFO) << partition_name_suffix
               << " is not in super partition metadata.";

     if (IsSuperBlockDevice(device_dir, current_slot, partition_name_suffix)) {
       LOG(ERROR) << "The static partition " << partition_name_suffix
                  << " is a block device for current metadata ("
                  << fs_mgr_get_super_partition_name(current_slot) << ", slot "
                  << BootControlInterface::SlotName(current_slot)
                  << "). It cannot be used as a logical partition.";
       return DynamicPartitionDeviceStatus::ERROR;
     }

     return DynamicPartitionDeviceStatus::TRY_STATIC;
   }

   if (slot == current_slot) {
     if (dynamic_control_->GetState(partition_name_suffix) !=
         DmDeviceState::ACTIVE) {
       LOG(WARNING) << partition_name_suffix << " is at current slot but it is "
                    << "not mapped. Now try to map it.";
     } else {
       if (dynamic_control_->GetDmDevicePathByName(partition_name_suffix,
                                                   device)) {
         LOG(INFO) << partition_name_suffix
                   << " is mapped on device mapper: " << *device;
         return DynamicPartitionDeviceStatus::SUCCESS;
       }
       LOG(ERROR) << partition_name_suffix << "is mapped but path is unknown.";
       return DynamicPartitionDeviceStatus::ERROR;
     }
   }

   bool force_writable = slot != current_slot;
   if (dynamic_control_->MapPartitionOnDeviceMapper(
           super_device, partition_name_suffix, slot, force_writable, device)) {
     return DynamicPartitionDeviceStatus::SUCCESS;
   }
   return DynamicPartitionDeviceStatus::ERROR;
 }

 bool BootControlAndroid::GetPartitionDevice(const string& partition_name,
                                             Slot slot,
                                             string* device) const {
   string suffix;
   if (!GetSuffix(slot, &suffix)) {
     return false;
   }
   const string partition_name_suffix = partition_name + suffix;

   string device_dir_str;
   if (!dynamic_control_->GetDeviceDir(&device_dir_str)) {
     return false;
   }
   base::FilePath device_dir(device_dir_str);

   // When looking up target partition devices, treat them as static if the
   // current payload doesn't encode them as dynamic partitions. This may happen
   // when applying a retrofit update on top of a dynamic-partitions-enabled
   // build.
   if (dynamic_control_->IsDynamicPartitionsEnabled() &&
       (slot == GetCurrentSlot() || is_target_dynamic_)) {
     switch (GetDynamicPartitionDevice(
         device_dir, partition_name_suffix, slot, device)) {
       case DynamicPartitionDeviceStatus::SUCCESS:
         return true;
       case DynamicPartitionDeviceStatus::TRY_STATIC:
         break;
       case DynamicPartitionDeviceStatus::ERROR:  // fallthrough
       default:
         return false;
     }
   }

   base::FilePath path = device_dir.Append(partition_name_suffix);
   if (!dynamic_control_->DeviceExists(path.value())) {
     LOG(ERROR) << "Device file " << path.value() << " does not exist.";
     return false;
   }

   *device = path.value();
   return true;
 }

 bool BootControlAndroid::IsSlotBootable(Slot slot) const {
   Return<BoolResult> ret = module_->isSlotBootable(slot);
   if (!ret.isOk()) {
     LOG(ERROR) << "Unable to determine if slot " << SlotName(slot)
                << " is bootable: " << ret.description();
     return false;
   }
   if (ret == BoolResult::INVALID_SLOT) {
     LOG(ERROR) << "Invalid slot: " << SlotName(slot);
     return false;
   }
   return ret == BoolResult::TRUE;
 }

 bool BootControlAndroid::MarkSlotUnbootable(Slot slot) {
   CommandResult result;
   auto ret = module_->setSlotAsUnbootable(slot, StoreResultCallback(&result));
   if (!ret.isOk()) {
     LOG(ERROR) << "Unable to call MarkSlotUnbootable for slot "
                << SlotName(slot) << ": " << ret.description();
     return false;
   }
   if (!result.success) {
     LOG(ERROR) << "Unable to mark slot " << SlotName(slot)
                << " as unbootable: " << result.errMsg.c_str();
   }
   return result.success;
 }

 bool BootControlAndroid::SetActiveBootSlot(Slot slot) {
   CommandResult result;
   auto ret = module_->setActiveBootSlot(slot, StoreResultCallback(&result));
   if (!ret.isOk()) {
     LOG(ERROR) << "Unable to call SetActiveBootSlot for slot " << SlotName(slot)
                << ": " << ret.description();
     return false;
   }
   if (!result.success) {
     LOG(ERROR) << "Unable to set the active slot to slot " << SlotName(slot)
                << ": " << result.errMsg.c_str();
   }
   return result.success;
 }

 bool BootControlAndroid::MarkBootSuccessfulAsync(
     base::Callback<void(bool)> callback) {
   CommandResult result;
   auto ret = module_->markBootSuccessful(StoreResultCallback(&result));
   if (!ret.isOk()) {
     LOG(ERROR) << "Unable to call MarkBootSuccessful: " << ret.description();
     return false;
   }
   if (!result.success) {
     LOG(ERROR) << "Unable to mark boot successful: " << result.errMsg.c_str();
   }
   return brillo::MessageLoop::current()->PostTask(
              FROM_HERE, base::Bind(callback, result.success)) !=
          brillo::MessageLoop::kTaskIdNull;
 }

 namespace {

 bool UpdatePartitionMetadata(DynamicPartitionControlInterface* dynamic_control,
                              Slot source_slot,
                              Slot target_slot,
                              const string& target_suffix,
                              const PartitionMetadata& partition_metadata) {
   string device_dir_str;
   if (!dynamic_control->GetDeviceDir(&device_dir_str)) {
     return false;
   }
   base::FilePath device_dir(device_dir_str);
   auto source_device =
       device_dir.Append(fs_mgr_get_super_partition_name(source_slot)).value();

   auto builder = dynamic_control->LoadMetadataBuilder(
       source_device, source_slot, target_slot);
   if (builder == nullptr) {
     // TODO(elsk): allow reconstructing metadata from partition_metadata
     // in recovery sideload.
     LOG(ERROR) << "No metadata at "
                << BootControlInterface::SlotName(source_slot);
     return false;
   }

   std::vector<string> groups = builder->ListGroups();
   for (const auto& group_name : groups) {
     if (base::EndsWith(
             group_name, target_suffix, base::CompareCase::SENSITIVE)) {
       LOG(INFO) << "Removing group " << group_name;
       builder->RemoveGroupAndPartitions(group_name);
     }
   }

   uint64_t total_size = 0;
   for (const auto& group : partition_metadata.groups) {
     total_size += group.size;
   }

   string expr;
   uint64_t allocatable_space = builder->AllocatableSpace();
   if (!dynamic_control->IsDynamicPartitionsRetrofit()) {
     allocatable_space /= 2;
     expr = "half of ";
   }
   if (total_size > allocatable_space) {
     LOG(ERROR) << "The maximum size of all groups with suffix " << target_suffix
                << " (" << total_size << ") has exceeded " << expr
                << " allocatable space for dynamic partitions "
                << allocatable_space << ".";
     return false;
   }

   for (const auto& group : partition_metadata.groups) {
     auto group_name_suffix = group.name + target_suffix;
     if (!builder->AddGroup(group_name_suffix, group.size)) {
       LOG(ERROR) << "Cannot add group " << group_name_suffix << " with size "
                  << group.size;
       return false;
     }
     LOG(INFO) << "Added group " << group_name_suffix << " with size "
               << group.size;

     for (const auto& partition : group.partitions) {
       auto partition_name_suffix = partition.name + target_suffix;
       Partition* p = builder->AddPartition(
           partition_name_suffix, group_name_suffix, LP_PARTITION_ATTR_READONLY);
       if (!p) {
         LOG(ERROR) << "Cannot add partition " << partition_name_suffix
                    << " to group " << group_name_suffix;
         return false;
       }
       if (!builder->ResizePartition(p, partition.size)) {
         LOG(ERROR) << "Cannot resize partition " << partition_name_suffix
                    << " to size " << partition.size << ". Not enough space?";
         return false;
       }
       LOG(INFO) << "Added partition " << partition_name_suffix << " to group "
                 << group_name_suffix << " with size " << partition.size;
     }
   }

   auto target_device =
       device_dir.Append(fs_mgr_get_super_partition_name(target_slot)).value();
   return dynamic_control->StoreMetadata(
       target_device, builder.get(), target_slot);
 }

 bool UnmapTargetPartitions(DynamicPartitionControlInterface* dynamic_control,
                            const string& target_suffix,
                            const PartitionMetadata& partition_metadata) {
   for (const auto& group : partition_metadata.groups) {
     for (const auto& partition : group.partitions) {
       if (!dynamic_control->UnmapPartitionOnDeviceMapper(
               partition.name + target_suffix, true /* wait */)) {
         return false;
       }
     }
   }
   return true;
 }

 }  // namespace

 bool BootControlAndroid::InitPartitionMetadata(
     Slot target_slot,
     const PartitionMetadata& partition_metadata,
     bool update_metadata) {
   if (fs_mgr_overlayfs_is_setup()) {
     // Non DAP devices can use overlayfs as well.
     LOG(WARNING)
         << "overlayfs overrides are active and can interfere with our "
            "resources.\n"
         << "run adb enable-verity to deactivate if required and try again.";
   }
   if (!dynamic_control_->IsDynamicPartitionsEnabled()) {
     return true;
   }

   auto source_slot = GetCurrentSlot();
   if (target_slot == source_slot) {
     LOG(ERROR) << "Cannot call InitPartitionMetadata on current slot.";
     return false;
   }

   // Although the current build supports dynamic partitions, the given payload
   // doesn't use it for target partitions. This could happen when applying a
   // retrofit update. Skip updating the partition metadata for the target slot.
   is_target_dynamic_ = !partition_metadata.groups.empty();
   if (!is_target_dynamic_) {
     return true;
   }

   if (!update_metadata) {
     return true;
   }

   string target_suffix;
   if (!GetSuffix(target_slot, &target_suffix)) {
     return false;
   }

   // Unmap all the target dynamic partitions because they would become
   // inconsistent with the new metadata.
   if (!UnmapTargetPartitions(
           dynamic_control_.get(), target_suffix, partition_metadata)) {
     return false;
   }

   return UpdatePartitionMetadata(dynamic_control_.get(),
                                  source_slot,
                                  target_slot,
                                  target_suffix,
                                  partition_metadata);
 }

 }  // namespace chromeos_update_engine
	//
	// Copyright (C) 2015 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/boot_control_android.h"

	#include <memory>
	#include <utility>
	#include <vector>

	#include <base/bind.h>
	#include <base/logging.h>
	#include <base/strings/string_util.h>
	#include <bootloader_message/bootloader_message.h>
	#include <brillo/message_loops/message_loop.h>
	#include <fs_mgr.h>
	#include <fs_mgr_overlayfs.h>

	#include "update_engine/common/utils.h"
	#include "update_engine/dynamic_partition_control_android.h"

	using std::string;

	using android::dm::DmDeviceState;
	using android::fs_mgr::Partition;
	using android::hardware::hidl_string;
	using android::hardware::Return;
	using android::hardware::boot::V1_0::BoolResult;
	using android::hardware::boot::V1_0::CommandResult;
	using android::hardware::boot::V1_0::IBootControl;
	using Slot = chromeos_update_engine::BootControlInterface::Slot;
	using PartitionMetadata =
	chromeos_update_engine::BootControlInterface::PartitionMetadata;

	namespace {

	auto StoreResultCallback(CommandResult* dest) {
	return [dest](const CommandResult& result) { *dest = result; };
	}
	} // namespace

	namespace chromeos_update_engine {

	namespace boot_control {

	// Factory defined in boot_control.h.
	std::unique_ptr<BootControlInterface> CreateBootControl() {
	auto boot_control = std::make_unique<BootControlAndroid>();
	if (!boot_control->Init()) {
	return nullptr;
	}
	return std::move(boot_control);
	}

	} // namespace boot_control

	bool BootControlAndroid::Init() {
	module_ = IBootControl::getService();
	if (module_ == nullptr) {
	LOG(ERROR) << "Error getting bootctrl HIDL module.";
	return false;
	}

	LOG(INFO) << "Loaded boot control hidl hal.";

	dynamic_control_ = std::make_unique<DynamicPartitionControlAndroid>();

	return true;
	}

	void BootControlAndroid::Cleanup() {
	dynamic_control_->Cleanup();
	}

	unsigned int BootControlAndroid::GetNumSlots() const {
	return module_->getNumberSlots();
	}

	BootControlInterface::Slot BootControlAndroid::GetCurrentSlot() const {
	return module_->getCurrentSlot();
	}

	bool BootControlAndroid::GetSuffix(Slot slot, string* suffix) const {
	auto store_suffix_cb = [&suffix](hidl_string cb_suffix) {
	*suffix = cb_suffix.c_str();
	};
	Return<void> ret = module_->getSuffix(slot, store_suffix_cb);

	if (!ret.isOk()) {
	LOG(ERROR) << "boot_control impl returned no suffix for slot "
	<< SlotName(slot);
	return false;
	}
	return true;
	}

	bool BootControlAndroid::IsSuperBlockDevice(
	const base::FilePath& device_dir,
	Slot slot,
	const string& partition_name_suffix) const {
	string source_device =
	device_dir.Append(fs_mgr_get_super_partition_name(slot)).value();
	auto source_metadata = dynamic_control_->LoadMetadataBuilder(
	source_device, slot, BootControlInterface::kInvalidSlot);
	return source_metadata->HasBlockDevice(partition_name_suffix);
	}

	BootControlAndroid::DynamicPartitionDeviceStatus
	BootControlAndroid::GetDynamicPartitionDevice(
	const base::FilePath& device_dir,
	const string& partition_name_suffix,
	Slot slot,
	string* device) const {
	string super_device =
	device_dir.Append(fs_mgr_get_super_partition_name(slot)).value();

	auto builder = dynamic_control_->LoadMetadataBuilder(
	super_device, slot, BootControlInterface::kInvalidSlot);

	if (builder == nullptr) {
	LOG(ERROR) << "No metadata in slot "
	<< BootControlInterface::SlotName(slot);
	return DynamicPartitionDeviceStatus::ERROR;
	}

	Slot current_slot = GetCurrentSlot();
	if (builder->FindPartition(partition_name_suffix) == nullptr) {
	LOG(INFO) << partition_name_suffix
	<< " is not in super partition metadata.";

	if (IsSuperBlockDevice(device_dir, current_slot, partition_name_suffix)) {
	LOG(ERROR) << "The static partition " << partition_name_suffix
	<< " is a block device for current metadata ("
	<< fs_mgr_get_super_partition_name(current_slot) << ", slot "
	<< BootControlInterface::SlotName(current_slot)
	<< "). It cannot be used as a logical partition.";
	return DynamicPartitionDeviceStatus::ERROR;
	}

	return DynamicPartitionDeviceStatus::TRY_STATIC;
	}

	if (slot == current_slot) {
	if (dynamic_control_->GetState(partition_name_suffix) !=
	DmDeviceState::ACTIVE) {
	LOG(WARNING) << partition_name_suffix << " is at current slot but it is "
	<< "not mapped. Now try to map it.";
	} else {
	if (dynamic_control_->GetDmDevicePathByName(partition_name_suffix,
	device)) {
	LOG(INFO) << partition_name_suffix
	<< " is mapped on device mapper: " << *device;
	return DynamicPartitionDeviceStatus::SUCCESS;
	}
	LOG(ERROR) << partition_name_suffix << "is mapped but path is unknown.";
	return DynamicPartitionDeviceStatus::ERROR;
	}
	}

	bool force_writable = slot != current_slot;
	if (dynamic_control_->MapPartitionOnDeviceMapper(
	super_device, partition_name_suffix, slot, force_writable, device)) {
	return DynamicPartitionDeviceStatus::SUCCESS;
	}
	return DynamicPartitionDeviceStatus::ERROR;
	}

	bool BootControlAndroid::GetPartitionDevice(const string& partition_name,
	Slot slot,
	string* device) const {
	string suffix;
	if (!GetSuffix(slot, &suffix)) {
	return false;
	}
	const string partition_name_suffix = partition_name + suffix;

	string device_dir_str;
	if (!dynamic_control_->GetDeviceDir(&device_dir_str)) {
	return false;
	}
	base::FilePath device_dir(device_dir_str);

	// When looking up target partition devices, treat them as static if the
	// current payload doesn't encode them as dynamic partitions. This may happen
	// when applying a retrofit update on top of a dynamic-partitions-enabled
	// build.
	if (dynamic_control_->IsDynamicPartitionsEnabled() &&
	(slot == GetCurrentSlot() \|\| is_target_dynamic_)) {
	switch (GetDynamicPartitionDevice(
	device_dir, partition_name_suffix, slot, device)) {
	case DynamicPartitionDeviceStatus::SUCCESS:
	return true;
	case DynamicPartitionDeviceStatus::TRY_STATIC:
	break;
	case DynamicPartitionDeviceStatus::ERROR: // fallthrough
	default:
	return false;
	}
	}

	base::FilePath path = device_dir.Append(partition_name_suffix);
	if (!dynamic_control_->DeviceExists(path.value())) {
	LOG(ERROR) << "Device file " << path.value() << " does not exist.";
	return false;
	}

	*device = path.value();
	return true;
	}

	bool BootControlAndroid::IsSlotBootable(Slot slot) const {
	Return<BoolResult> ret = module_->isSlotBootable(slot);
	if (!ret.isOk()) {
	LOG(ERROR) << "Unable to determine if slot " << SlotName(slot)
	<< " is bootable: " << ret.description();
	return false;
	}
	if (ret == BoolResult::INVALID_SLOT) {
	LOG(ERROR) << "Invalid slot: " << SlotName(slot);
	return false;
	}
	return ret == BoolResult::TRUE;
	}

	bool BootControlAndroid::MarkSlotUnbootable(Slot slot) {
	CommandResult result;
	auto ret = module_->setSlotAsUnbootable(slot, StoreResultCallback(&result));
	if (!ret.isOk()) {
	LOG(ERROR) << "Unable to call MarkSlotUnbootable for slot "
	<< SlotName(slot) << ": " << ret.description();
	return false;
	}
	if (!result.success) {
	LOG(ERROR) << "Unable to mark slot " << SlotName(slot)
	<< " as unbootable: " << result.errMsg.c_str();
	}
	return result.success;
	}

	bool BootControlAndroid::SetActiveBootSlot(Slot slot) {
	CommandResult result;
	auto ret = module_->setActiveBootSlot(slot, StoreResultCallback(&result));
	if (!ret.isOk()) {
	LOG(ERROR) << "Unable to call SetActiveBootSlot for slot " << SlotName(slot)
	<< ": " << ret.description();
	return false;
	}
	if (!result.success) {
	LOG(ERROR) << "Unable to set the active slot to slot " << SlotName(slot)
	<< ": " << result.errMsg.c_str();
	}
	return result.success;
	}

	bool BootControlAndroid::MarkBootSuccessfulAsync(
	base::Callback<void(bool)> callback) {
	CommandResult result;
	auto ret = module_->markBootSuccessful(StoreResultCallback(&result));
	if (!ret.isOk()) {
	LOG(ERROR) << "Unable to call MarkBootSuccessful: " << ret.description();
	return false;
	}
	if (!result.success) {
	LOG(ERROR) << "Unable to mark boot successful: " << result.errMsg.c_str();
	}
	return brillo::MessageLoop::current()->PostTask(
	FROM_HERE, base::Bind(callback, result.success)) !=
	brillo::MessageLoop::kTaskIdNull;
	}

	namespace {

	bool UpdatePartitionMetadata(DynamicPartitionControlInterface* dynamic_control,
	Slot source_slot,
	Slot target_slot,
	const string& target_suffix,
	const PartitionMetadata& partition_metadata) {
	string device_dir_str;
	if (!dynamic_control->GetDeviceDir(&device_dir_str)) {
	return false;
	}
	base::FilePath device_dir(device_dir_str);
	auto source_device =
	device_dir.Append(fs_mgr_get_super_partition_name(source_slot)).value();

	auto builder = dynamic_control->LoadMetadataBuilder(
	source_device, source_slot, target_slot);
	if (builder == nullptr) {
	// TODO(elsk): allow reconstructing metadata from partition_metadata
	// in recovery sideload.
	LOG(ERROR) << "No metadata at "
	<< BootControlInterface::SlotName(source_slot);
	return false;
	}

	std::vector<string> groups = builder->ListGroups();
	for (const auto& group_name : groups) {
	if (base::EndsWith(
	group_name, target_suffix, base::CompareCase::SENSITIVE)) {
	LOG(INFO) << "Removing group " << group_name;
	builder->RemoveGroupAndPartitions(group_name);
	}
	}

	uint64_t total_size = 0;
	for (const auto& group : partition_metadata.groups) {
	total_size += group.size;
	}

	string expr;
	uint64_t allocatable_space = builder->AllocatableSpace();
	if (!dynamic_control->IsDynamicPartitionsRetrofit()) {
	allocatable_space /= 2;
	expr = "half of ";
	}
	if (total_size > allocatable_space) {
	LOG(ERROR) << "The maximum size of all groups with suffix " << target_suffix
	<< " (" << total_size << ") has exceeded " << expr
	<< " allocatable space for dynamic partitions "
	<< allocatable_space << ".";
	return false;
	}

	for (const auto& group : partition_metadata.groups) {
	auto group_name_suffix = group.name + target_suffix;
	if (!builder->AddGroup(group_name_suffix, group.size)) {
	LOG(ERROR) << "Cannot add group " << group_name_suffix << " with size "
	<< group.size;
	return false;
	}
	LOG(INFO) << "Added group " << group_name_suffix << " with size "
	<< group.size;

	for (const auto& partition : group.partitions) {
	auto partition_name_suffix = partition.name + target_suffix;
	Partition* p = builder->AddPartition(
	partition_name_suffix, group_name_suffix, LP_PARTITION_ATTR_READONLY);
	if (!p) {
	LOG(ERROR) << "Cannot add partition " << partition_name_suffix
	<< " to group " << group_name_suffix;
	return false;
	}
	if (!builder->ResizePartition(p, partition.size)) {
	LOG(ERROR) << "Cannot resize partition " << partition_name_suffix
	<< " to size " << partition.size << ". Not enough space?";
	return false;
	}
	LOG(INFO) << "Added partition " << partition_name_suffix << " to group "
	<< group_name_suffix << " with size " << partition.size;
	}
	}

	auto target_device =
	device_dir.Append(fs_mgr_get_super_partition_name(target_slot)).value();
	return dynamic_control->StoreMetadata(
	target_device, builder.get(), target_slot);
	}

	bool UnmapTargetPartitions(DynamicPartitionControlInterface* dynamic_control,
	const string& target_suffix,
	const PartitionMetadata& partition_metadata) {
	for (const auto& group : partition_metadata.groups) {
	for (const auto& partition : group.partitions) {
	if (!dynamic_control->UnmapPartitionOnDeviceMapper(
	partition.name + target_suffix, true /* wait */)) {
	return false;
	}
	}
	}
	return true;
	}

	} // namespace

	bool BootControlAndroid::InitPartitionMetadata(
	Slot target_slot,
	const PartitionMetadata& partition_metadata,
	bool update_metadata) {
	if (fs_mgr_overlayfs_is_setup()) {
	// Non DAP devices can use overlayfs as well.
	LOG(WARNING)
	<< "overlayfs overrides are active and can interfere with our "
	"resources.\n"
	<< "run adb enable-verity to deactivate if required and try again.";
	}
	if (!dynamic_control_->IsDynamicPartitionsEnabled()) {
	return true;
	}

	auto source_slot = GetCurrentSlot();
	if (target_slot == source_slot) {
	LOG(ERROR) << "Cannot call InitPartitionMetadata on current slot.";
	return false;
	}

	// Although the current build supports dynamic partitions, the given payload
	// doesn't use it for target partitions. This could happen when applying a
	// retrofit update. Skip updating the partition metadata for the target slot.
	is_target_dynamic_ = !partition_metadata.groups.empty();
	if (!is_target_dynamic_) {
	return true;
	}

	if (!update_metadata) {
	return true;
	}

	string target_suffix;
	if (!GetSuffix(target_slot, &target_suffix)) {
	return false;
	}

	// Unmap all the target dynamic partitions because they would become
	// inconsistent with the new metadata.
	if (!UnmapTargetPartitions(
	dynamic_control_.get(), target_suffix, partition_metadata)) {
	return false;
	}

	return UpdatePartitionMetadata(dynamic_control_.get(),
	source_slot,
	target_slot,
	target_suffix,
	partition_metadata);
	}

	} // namespace chromeos_update_engine