init: Factor out first-stage uevent handling into a separate class. (41175597) · Commits · e / os / android_system_core

init/Android.bp

+1 −0

Original line number	Diff line number	Diff line
		@@ -36,6 +36,7 @@ init_common_sources = [
		"util.cpp",
		]
		init_device_sources = [
		"block_dev_initializer.cpp",
		"bootchart.cpp",
		"builtins.cpp",
		"devices.cpp",

init/Android.mk

+1 −0

Original line number	Diff line number	Diff line
		@@ -48,6 +48,7 @@ ifneq ($(BOARD_BUILD_SYSTEM_ROOT_IMAGE),true)
		include $(CLEAR_VARS)
		LOCAL_CPPFLAGS := $(init_cflags)
		LOCAL_SRC_FILES := \
		block_dev_initializer.cpp \
		devices.cpp \
		first_stage_init.cpp \
		first_stage_main.cpp \

init/block_dev_initializer.cpp

0 → 100644

+148 −0

Original line number	Diff line number	Diff line
		// Copyright (C) 2020 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 <chrono>
		#include <string_view>
		#include <vector>

		#include <android-base/chrono_utils.h>
		#include <android-base/logging.h>
		#include <android-base/strings.h>
		#include <fs_mgr.h>

		#include "block_dev_initializer.h"

		namespace android {
		namespace init {

		using android::base::Timer;
		using namespace std::chrono_literals;

		BlockDevInitializer::BlockDevInitializer() : uevent_listener_(16 * 1024 * 1024) {
		auto boot_devices = android::fs_mgr::GetBootDevices();
		device_handler_ = std::make_unique<DeviceHandler>(
		std::vector<Permissions>{}, std::vector<SysfsPermissions>{}, std::vector<Subsystem>{},
		std::move(boot_devices), false);
		}

		bool BlockDevInitializer::InitDeviceMapper() {
		const std::string dm_path = "/devices/virtual/misc/device-mapper";
		bool found = false;
		auto dm_callback = [this, &dm_path, &found](const Uevent& uevent) {
		if (uevent.path == dm_path) {
		device_handler_->HandleUevent(uevent);
		found = true;
		return ListenerAction::kStop;
		}
		return ListenerAction::kContinue;
		};
		uevent_listener_.RegenerateUeventsForPath("/sys" + dm_path, dm_callback);
		if (!found) {
		LOG(INFO) << "device-mapper device not found in /sys, waiting for its uevent";
		Timer t;
		uevent_listener_.Poll(dm_callback, 10s);
		LOG(INFO) << "Wait for device-mapper returned after " << t;
		}
		if (!found) {
		LOG(ERROR) << "device-mapper device not found after polling timeout";
		return false;
		}
		return true;
		}

		ListenerAction BlockDevInitializer::HandleUevent(const Uevent& uevent,
		std::set<std::string>* devices) {
		// Ignore everything that is not a block device.
		if (uevent.subsystem != "block") {
		return ListenerAction::kContinue;
		}

		auto name = uevent.partition_name;
		if (name.empty()) {
		size_t base_idx = uevent.path.rfind('/');
		if (base_idx == std::string::npos) {
		return ListenerAction::kContinue;
		}
		name = uevent.path.substr(base_idx + 1);
		}

		auto iter = devices->find(name);
		if (iter == devices->end()) {
		return ListenerAction::kContinue;
		}

		LOG(VERBOSE) << __PRETTY_FUNCTION__ << ": found partition: " << name;

		devices->erase(iter);
		device_handler_->HandleUevent(uevent);
		return devices->empty() ? ListenerAction::kStop : ListenerAction::kContinue;
		}

		bool BlockDevInitializer::InitDevices(std::set<std::string> devices) {
		auto uevent_callback = [&, this](const Uevent& uevent) -> ListenerAction {
		return HandleUevent(uevent, &devices);
		};
		uevent_listener_.RegenerateUevents(uevent_callback);

		// UeventCallback() will remove found partitions from \|devices\|. So if it
		// isn't empty here, it means some partitions are not found.
		if (!devices.empty()) {
		LOG(INFO) << __PRETTY_FUNCTION__
		<< ": partition(s) not found in /sys, waiting for their uevent(s): "
		<< android::base::Join(devices, ", ");
		Timer t;
		uevent_listener_.Poll(uevent_callback, 10s);
		LOG(INFO) << "Wait for partitions returned after " << t;
		}

		if (!devices.empty()) {
		LOG(ERROR) << __PRETTY_FUNCTION__ << ": partition(s) not found after polling timeout: "
		<< android::base::Join(devices, ", ");
		return false;
		}
		return true;
		}

		// Creates "/dev/block/dm-XX" for dm nodes by running coldboot on /sys/block/dm-XX.
		bool BlockDevInitializer::InitDmDevice(const std::string& device) {
		const std::string device_name(basename(device.c_str()));
		const std::string syspath = "/sys/block/" + device_name;
		bool found = false;

		auto uevent_callback = [&device_name, &device, this, &found](const Uevent& uevent) {
		if (uevent.device_name == device_name) {
		LOG(VERBOSE) << "Creating device-mapper device : " << device;
		device_handler_->HandleUevent(uevent);
		found = true;
		return ListenerAction::kStop;
		}
		return ListenerAction::kContinue;
		};

		uevent_listener_.RegenerateUeventsForPath(syspath, uevent_callback);
		if (!found) {
		LOG(INFO) << "dm device '" << device << "' not found in /sys, waiting for its uevent";
		Timer t;
		uevent_listener_.Poll(uevent_callback, 10s);
		LOG(INFO) << "wait for dm device '" << device << "' returned after " << t;
		}
		if (!found) {
		LOG(ERROR) << "dm device '" << device << "' not found after polling timeout";
		return false;
		}
		return true;
		}

		} // namespace init
		} // namespace android

init/block_dev_initializer.h

0 → 100644

+41 −0

Original line number	Diff line number	Diff line
		// Copyright (C) 2020 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 <memory>
		#include <set>
		#include <string>

		#include "devices.h"
		#include "uevent_listener.h"

		namespace android {
		namespace init {

		class BlockDevInitializer final {
		public:
		BlockDevInitializer();

		bool InitDeviceMapper();
		bool InitDevices(std::set<std::string> devices);
		bool InitDmDevice(const std::string& device);

		private:
		ListenerAction HandleUevent(const Uevent& uevent, std::set<std::string>* devices);

		std::unique_ptr<DeviceHandler> device_handler_;
		UeventListener uevent_listener_;
		};

		} // namespace init
		} // namespace android

init/first_stage_mount.cpp

+11 −139

Original line number	Diff line number	Diff line
		@@ -42,6 +42,7 @@
		#include <liblp/liblp.h>
		#include <libsnapshot/snapshot.h>

		#include "block_dev_initializer.h"
		#include "devices.h"
		#include "switch_root.h"
		#include "uevent.h"
		@@ -84,11 +85,7 @@ class FirstStageMount {
		bool InitDevices();

		protected:
		ListenerAction HandleBlockDevice(const std::string& name, const Uevent&,
		std::set<std::string>* required_devices);
		bool InitRequiredDevices(std::set<std::string> devices);
		bool InitMappedDevice(const std::string& verity_device);
		bool InitDeviceMapper();
		bool CreateLogicalPartitions();
		bool MountPartition(const Fstab::iterator& begin, bool erase_same_mounts,
		Fstab::iterator* end = nullptr);
		@@ -106,8 +103,6 @@ class FirstStageMount {
		// revocation check by DSU installation service.
		void CopyDsuAvbKeys();

		ListenerAction UeventCallback(const Uevent& uevent, std::set<std::string>* required_devices);

		// Pure virtual functions.
		virtual bool GetDmVerityDevices(std::set<std::string>* devices) = 0;
		virtual bool SetUpDmVerity(FstabEntry* fstab_entry) = 0;
		@@ -119,8 +114,7 @@ class FirstStageMount {
		// The super path is only set after InitDevices, and is invalid before.
		std::string super_path_;
		std::string super_partition_name_;
		std::unique_ptr<DeviceHandler> device_handler_;
		UeventListener uevent_listener_;
		BlockDevInitializer block_dev_init_;
		// Reads all AVB keys before chroot into /system, as they might be used
		// later when mounting other partitions, e.g., /vendor and /product.
		std::map<std::string, std::vector<std::string>> preload_avb_key_blobs_;
		@@ -234,13 +228,7 @@ static bool IsStandaloneImageRollback(const AvbHandle& builtin_vbmeta,

		// Class Definitions
		// -----------------
		FirstStageMount::FirstStageMount(Fstab fstab)
		: need_dm_verity_(false), fstab_(std::move(fstab)), uevent_listener_(16 * 1024 * 1024) {
		auto boot_devices = android::fs_mgr::GetBootDevices();
		device_handler_ = std::make_unique<DeviceHandler>(
		std::vector<Permissions>{}, std::vector<SysfsPermissions>{}, std::vector<Subsystem>{},
		std::move(boot_devices), false);

		FirstStageMount::FirstStageMount(Fstab fstab) : need_dm_verity_(false), fstab_(std::move(fstab)) {
		super_partition_name_ = fs_mgr_get_super_partition_name();
		}

		@@ -308,62 +296,13 @@ void FirstStageMount::GetSuperDeviceName(std::set<std::string>* devices) {
		// Found partitions will then be removed from it for the subsequent member
		// function to check which devices are NOT created.
		bool FirstStageMount::InitRequiredDevices(std::set<std::string> devices) {
		if (!InitDeviceMapper()) {
		if (!block_dev_init_.InitDeviceMapper()) {
		return false;
		}

		if (devices.empty()) {
		return true;
		}

		auto uevent_callback = [&, this](const Uevent& uevent) {
		return UeventCallback(uevent, &devices);
		};
		uevent_listener_.RegenerateUevents(uevent_callback);

		// UeventCallback() will remove found partitions from \|devices\|. So if it
		// isn't empty here, it means some partitions are not found.
		if (!devices.empty()) {
		LOG(INFO) << __PRETTY_FUNCTION__
		<< ": partition(s) not found in /sys, waiting for their uevent(s): "
		<< android::base::Join(devices, ", ");
		Timer t;
		uevent_listener_.Poll(uevent_callback, 10s);
		LOG(INFO) << "Wait for partitions returned after " << t;
		}

		if (!devices.empty()) {
		LOG(ERROR) << __PRETTY_FUNCTION__ << ": partition(s) not found after polling timeout: "
		<< android::base::Join(devices, ", ");
		return false;
		}

		return true;
		}

		bool FirstStageMount::InitDeviceMapper() {
		const std::string dm_path = "/devices/virtual/misc/device-mapper";
		bool found = false;
		auto dm_callback = [this, &dm_path, &found](const Uevent& uevent) {
		if (uevent.path == dm_path) {
		device_handler_->HandleUevent(uevent);
		found = true;
		return ListenerAction::kStop;
		}
		return ListenerAction::kContinue;
		};
		uevent_listener_.RegenerateUeventsForPath("/sys" + dm_path, dm_callback);
		if (!found) {
		LOG(INFO) << "device-mapper device not found in /sys, waiting for its uevent";
		Timer t;
		uevent_listener_.Poll(dm_callback, 10s);
		LOG(INFO) << "Wait for device-mapper returned after " << t;
		}
		if (!found) {
		LOG(ERROR) << "device-mapper device not found after polling timeout";
		return false;
		}
		return true;
		return block_dev_init_.InitDevices(std::move(devices));
		}

		bool FirstStageMount::InitDmLinearBackingDevices(const android::fs_mgr::LpMetadata& metadata) {
		@@ -419,75 +358,6 @@ bool FirstStageMount::CreateLogicalPartitions() {
		return android::fs_mgr::CreateLogicalPartitions(*metadata.get(), super_path_);
		}

		ListenerAction FirstStageMount::HandleBlockDevice(const std::string& name, const Uevent& uevent,
		std::set<std::string>* required_devices) {
		// Matches partition name to create device nodes.
		// Both required_devices_partition_names_ and uevent->partition_name have A/B
		// suffix when A/B is used.
		auto iter = required_devices->find(name);
		if (iter != required_devices->end()) {
		LOG(VERBOSE) << __PRETTY_FUNCTION__ << ": found partition: " << *iter;
		required_devices->erase(iter);
		device_handler_->HandleUevent(uevent);
		if (required_devices->empty()) {
		return ListenerAction::kStop;
		} else {
		return ListenerAction::kContinue;
		}
		}
		return ListenerAction::kContinue;
		}

		ListenerAction FirstStageMount::UeventCallback(const Uevent& uevent,
		std::set<std::string>* required_devices) {
		// Ignores everything that is not a block device.
		if (uevent.subsystem != "block") {
		return ListenerAction::kContinue;
		}

		if (!uevent.partition_name.empty()) {
		return HandleBlockDevice(uevent.partition_name, uevent, required_devices);
		} else {
		size_t base_idx = uevent.path.rfind('/');
		if (base_idx != std::string::npos) {
		return HandleBlockDevice(uevent.path.substr(base_idx + 1), uevent, required_devices);
		}
		}
		// Not found a partition or find an unneeded partition, continue to find others.
		return ListenerAction::kContinue;
		}

		// Creates "/dev/block/dm-XX" for dm-verity by running coldboot on /sys/block/dm-XX.
		bool FirstStageMount::InitMappedDevice(const std::string& dm_device) {
		const std::string device_name(basename(dm_device.c_str()));
		const std::string syspath = "/sys/block/" + device_name;
		bool found = false;

		auto verity_callback = [&device_name, &dm_device, this, &found](const Uevent& uevent) {
		if (uevent.device_name == device_name) {
		LOG(VERBOSE) << "Creating device-mapper device : " << dm_device;
		device_handler_->HandleUevent(uevent);
		found = true;
		return ListenerAction::kStop;
		}
		return ListenerAction::kContinue;
		};

		uevent_listener_.RegenerateUeventsForPath(syspath, verity_callback);
		if (!found) {
		LOG(INFO) << "dm device '" << dm_device << "' not found in /sys, waiting for its uevent";
		Timer t;
		uevent_listener_.Poll(verity_callback, 10s);
		LOG(INFO) << "wait for dm device '" << dm_device << "' returned after " << t;
		}
		if (!found) {
		LOG(ERROR) << "dm device '" << dm_device << "' not found after polling timeout";
		return false;
		}

		return true;
		}

		bool FirstStageMount::MountPartition(const Fstab::iterator& begin, bool erase_same_mounts,
		Fstab::iterator* end) {
		// Sets end to begin + 1, so we can just return on failure below.
		@@ -499,7 +369,7 @@ bool FirstStageMount::MountPartition(const Fstab::iterator& begin, bool erase_sa
		if (!fs_mgr_update_logical_partition(&(*begin))) {
		return false;
		}
		if (!InitMappedDevice(begin->blk_device)) {
		if (!block_dev_init_.InitDmDevice(begin->blk_device)) {
		return false;
		}
		}
		@@ -666,7 +536,9 @@ bool FirstStageMount::MountPartitions() {
		auto init_devices = [this](std::set<std::string> devices) -> bool {
		for (auto iter = devices.begin(); iter != devices.end();) {
		if (android::base::StartsWith(*iter, "/dev/block/dm-")) {
		if (!InitMappedDevice(*iter)) return false;
		if (!block_dev_init_.InitDmDevice(*iter)) {
		return false;
		}
		iter = devices.erase(iter);
		} else {
		iter++;
		@@ -782,7 +654,7 @@ bool FirstStageMountVBootV1::SetUpDmVerity(FstabEntry* fstab_entry) {
		// The exact block device name (fstab_rec->blk_device) is changed to
		// "/dev/block/dm-XX". Needs to create it because ueventd isn't started in init
		// first stage.
		return InitMappedDevice(fstab_entry->blk_device);
		return block_dev_init_.InitDmDevice(fstab_entry->blk_device);
		default:
		return false;
		}
		@@ -902,7 +774,7 @@ bool FirstStageMountVBootV2::SetUpDmVerity(FstabEntry* fstab_entry) {
		// The exact block device name (fstab_rec->blk_device) is changed to
		// "/dev/block/dm-XX". Needs to create it because ueventd isn't started in init
		// first stage.
		return InitMappedDevice(fstab_entry->blk_device);
		return block_dev_init_.InitDmDevice(fstab_entry->blk_device);
		default:
		return false;
		}