Merge "init: Allow persistent properties to be written asynchronously." (9b9924b4) · Commits · e / os / android_system_core

init/README.md

+11 −0

Original line number	Original line	Diff line number	Diff line
	@@ -174,6 +174,17 @@ If the property `true` becomes `true` AFTER `boot` was triggered, nothing will
	be executed. The condition `boot && property:true=true` will be evaluated to		be executed. The condition `boot && property:true=true` will be evaluated to
	false because the `boot` trigger is a past event.		false because the `boot` trigger is a past event.

			Note that when `ro.property_service.async_persist_writes` is `true`, there is no
			defined ordering between persistent setprops and non-persistent setprops. For
			example:

			on boot
			setprop a 1
			setprop persist.b 2

			When `ro.property_service.async_persist_writes` is `true`, triggers for these
			two properties may execute in any order.

	Services		Services
	--------		--------
	Services are programs which init launches and (optionally) restarts		Services are programs which init launches and (optionally) restarts

init/property_service.cpp

+165 −61

Original line number	Original line	Diff line number	Diff line
	@@ -98,6 +98,9 @@ using android::sysprop::InitProperties::is_userspace_reboot_supported;

	namespace android {		namespace android {
	namespace init {		namespace init {

			class PersistWriteThread;

	constexpr auto FINGERPRINT_PROP = "ro.build.fingerprint";		constexpr auto FINGERPRINT_PROP = "ro.build.fingerprint";
	constexpr auto LEGACY_FINGERPRINT_PROP = "ro.build.legacy.fingerprint";		constexpr auto LEGACY_FINGERPRINT_PROP = "ro.build.legacy.fingerprint";
	constexpr auto ID_PROP = "ro.build.id";		constexpr auto ID_PROP = "ro.build.id";
	@@ -115,6 +118,8 @@ static bool accept_messages = false;
	static std::mutex accept_messages_lock;		static std::mutex accept_messages_lock;
	static std::thread property_service_thread;		static std::thread property_service_thread;

			static std::unique_ptr<PersistWriteThread> persist_write_thread;

	static PropertyInfoAreaFile property_info_area;		static PropertyInfoAreaFile property_info_area;

	struct PropertyAuditData {		struct PropertyAuditData {
	@@ -177,48 +182,13 @@ static bool CheckMacPerms(const std::string& name, const char* target_context,
	return has_access;		return has_access;
	}		}

	static uint32_t PropertySet(const std::string& name, const std::string& value, std::string* error) {		void NotifyPropertyChange(const std::string& name, const std::string& value) {
	size_t valuelen = value.size();

	if (!IsLegalPropertyName(name)) {
	*error = "Illegal property name";
	return PROP_ERROR_INVALID_NAME;
	}

	if (auto result = IsLegalPropertyValue(name, value); !result.ok()) {
	*error = result.error().message();
	return PROP_ERROR_INVALID_VALUE;
	}

	prop_info* pi = (prop_info*) __system_property_find(name.c_str());
	if (pi != nullptr) {
	// ro.* properties are actually "write-once".
	if (StartsWith(name, "ro.")) {
	*error = "Read-only property was already set";
	return PROP_ERROR_READ_ONLY_PROPERTY;
	}

	__system_property_update(pi, value.c_str(), valuelen);
	} else {
	int rc = __system_property_add(name.c_str(), name.size(), value.c_str(), valuelen);
	if (rc < 0) {
	*error = "__system_property_add failed";
	return PROP_ERROR_SET_FAILED;
	}
	}

	// Don't write properties to disk until after we have read all default
	// properties to prevent them from being overwritten by default values.
	if (persistent_properties_loaded && StartsWith(name, "persist.")) {
	WritePersistentProperty(name, value);
	}
	// If init hasn't started its main loop, then it won't be handling property changed messages		// If init hasn't started its main loop, then it won't be handling property changed messages
	// anyway, so there's no need to try to send them.		// anyway, so there's no need to try to send them.
	auto lock = std::lock_guard{accept_messages_lock};		auto lock = std::lock_guard{accept_messages_lock};
	if (accept_messages) {		if (accept_messages) {
	PropertyChanged(name, value);		PropertyChanged(name, value);
	}		}
	return PROP_SUCCESS;
	}		}

	class AsyncRestorecon {		class AsyncRestorecon {
	@@ -259,7 +229,9 @@ class AsyncRestorecon {

	class SocketConnection {		class SocketConnection {
	public:		public:
			SocketConnection() = default;
	SocketConnection(int socket, const ucred& cred) : socket_(socket), cred_(cred) {}		SocketConnection(int socket, const ucred& cred) : socket_(socket), cred_(cred) {}
			SocketConnection(SocketConnection&&) = default;

	bool RecvUint32(uint32_t* value, uint32_t* timeout_ms) {		bool RecvUint32(uint32_t* value, uint32_t* timeout_ms) {
	return RecvFully(value, sizeof(*value), timeout_ms);		return RecvFully(value, sizeof(*value), timeout_ms);
	@@ -318,6 +290,8 @@ class SocketConnection {

	const ucred& cred() { return cred_; }		const ucred& cred() { return cred_; }

			SocketConnection& operator=(SocketConnection&&) = default;

	private:		private:
	bool PollIn(uint32_t* timeout_ms) {		bool PollIn(uint32_t* timeout_ms) {
	struct pollfd ufd = {		struct pollfd ufd = {
	@@ -388,9 +362,78 @@ class SocketConnection {
	unique_fd socket_;		unique_fd socket_;
	ucred cred_;		ucred cred_;

	DISALLOW_IMPLICIT_CONSTRUCTORS(SocketConnection);		DISALLOW_COPY_AND_ASSIGN(SocketConnection);
	};		};

			class PersistWriteThread {
			public:
			PersistWriteThread();
			void Write(std::string name, std::string value, SocketConnection socket);

			private:
			void Work();

			private:
			std::thread thread_;
			std::mutex mutex_;
			std::condition_variable cv_;
			std::deque<std::tuple<std::string, std::string, SocketConnection>> work_;
			};

			static std::optional<uint32_t> PropertySet(const std::string& name, const std::string& value,
			SocketConnection* socket, std::string* error) {
			size_t valuelen = value.size();

			if (!IsLegalPropertyName(name)) {
			*error = "Illegal property name";
			return {PROP_ERROR_INVALID_NAME};
			}

			if (auto result = IsLegalPropertyValue(name, value); !result.ok()) {
			*error = result.error().message();
			return {PROP_ERROR_INVALID_VALUE};
			}

			prop_info* pi = (prop_info*)__system_property_find(name.c_str());
			if (pi != nullptr) {
			// ro.* properties are actually "write-once".
			if (StartsWith(name, "ro.")) {
			*error = "Read-only property was already set";
			return {PROP_ERROR_READ_ONLY_PROPERTY};
			}

			__system_property_update(pi, value.c_str(), valuelen);
			} else {
			int rc = __system_property_add(name.c_str(), name.size(), value.c_str(), valuelen);
			if (rc < 0) {
			*error = "__system_property_add failed";
			return {PROP_ERROR_SET_FAILED};
			}
			}

			// Don't write properties to disk until after we have read all default
			// properties to prevent them from being overwritten by default values.
			if (socket && persistent_properties_loaded && StartsWith(name, "persist.")) {
			if (persist_write_thread) {
			persist_write_thread->Write(name, value, std::move(*socket));
			return {};
			}
			WritePersistentProperty(name, value);
			}

			NotifyPropertyChange(name, value);
			return {PROP_SUCCESS};
			}

			// Helper for PropertySet, for the case where no socket is used, and therefore an asynchronous
			// return is not possible.
			static uint32_t PropertySetNoSocket(const std::string& name, const std::string& value,
			std::string* error) {
			auto ret = PropertySet(name, value, nullptr, error);
			CHECK(ret.has_value());
			return *ret;
			}

	static uint32_t SendControlMessage(const std::string& msg, const std::string& name, pid_t pid,		static uint32_t SendControlMessage(const std::string& msg, const std::string& name, pid_t pid,
	SocketConnection* socket, std::string* error) {		SocketConnection* socket, std::string* error) {
	auto lock = std::lock_guard{accept_messages_lock};		auto lock = std::lock_guard{accept_messages_lock};
	@@ -481,16 +524,17 @@ uint32_t CheckPermissions(const std::string& name, const std::string& value,
	return PROP_SUCCESS;		return PROP_SUCCESS;
	}		}

	// This returns one of the enum of PROP_SUCCESS or PROP_ERROR*.		// This returns one of the enum of PROP_SUCCESS or PROP_ERROR*, or std::nullopt
	uint32_t HandlePropertySet(const std::string& name, const std::string& value,		// if asynchronous.
			std::optional<uint32_t> HandlePropertySet(const std::string& name, const std::string& value,
	const std::string& source_context, const ucred& cr,		const std::string& source_context, const ucred& cr,
	SocketConnection* socket, std::string* error) {		SocketConnection* socket, std::string* error) {
	if (auto ret = CheckPermissions(name, value, source_context, cr, error); ret != PROP_SUCCESS) {		if (auto ret = CheckPermissions(name, value, source_context, cr, error); ret != PROP_SUCCESS) {
	return ret;		return {ret};
	}		}

	if (StartsWith(name, "ctl.")) {		if (StartsWith(name, "ctl.")) {
	return SendControlMessage(name.c_str() + 4, value, cr.pid, socket, error);		return {SendControlMessage(name.c_str() + 4, value, cr.pid, socket, error)};
	}		}

	// sys.powerctl is a special property that is used to make the device reboot. We want to log		// sys.powerctl is a special property that is used to make the device reboot. We want to log
	@@ -511,7 +555,7 @@ uint32_t HandlePropertySet(const std::string& name, const std::string& value,
	}		}
	if (value == "reboot,userspace" && !is_userspace_reboot_supported().value_or(false)) {		if (value == "reboot,userspace" && !is_userspace_reboot_supported().value_or(false)) {
	*error = "Userspace reboot is not supported by this device";		*error = "Userspace reboot is not supported by this device";
	return PROP_ERROR_INVALID_VALUE;		return {PROP_ERROR_INVALID_VALUE};
	}		}
	}		}

	@@ -522,10 +566,20 @@ uint32_t HandlePropertySet(const std::string& name, const std::string& value,
	if (name == kRestoreconProperty && cr.pid != 1 && !value.empty()) {		if (name == kRestoreconProperty && cr.pid != 1 && !value.empty()) {
	static AsyncRestorecon async_restorecon;		static AsyncRestorecon async_restorecon;
	async_restorecon.TriggerRestorecon(value);		async_restorecon.TriggerRestorecon(value);
	return PROP_SUCCESS;		return {PROP_SUCCESS};
			}

			return PropertySet(name, value, socket, error);
	}		}

	return PropertySet(name, value, error);		// Helper for HandlePropertySet, for the case where no socket is used, and
			// therefore an asynchronous return is not possible.
			uint32_t HandlePropertySetNoSocket(const std::string& name, const std::string& value,
			const std::string& source_context, const ucred& cr,
			std::string* error) {
			auto ret = HandlePropertySet(name, value, source_context, cr, nullptr, error);
			CHECK(ret.has_value());
			return *ret;
	}		}

	static void handle_property_set_fd() {		static void handle_property_set_fd() {
	@@ -576,8 +630,7 @@ static void handle_property_set_fd() {

	const auto& cr = socket.cred();		const auto& cr = socket.cred();
	std::string error;		std::string error;
	uint32_t result =		auto result = HandlePropertySetNoSocket(prop_name, prop_value, source_context, cr, &error);
	HandlePropertySet(prop_name, prop_value, source_context, cr, nullptr, &error);
	if (result != PROP_SUCCESS) {		if (result != PROP_SUCCESS) {
	LOG(ERROR) << "Unable to set property '" << prop_name << "' from uid:" << cr.uid		LOG(ERROR) << "Unable to set property '" << prop_name << "' from uid:" << cr.uid
	<< " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;		<< " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;
	@@ -603,14 +656,19 @@ static void handle_property_set_fd() {
	return;		return;
	}		}

			// HandlePropertySet takes ownership of the socket if the set is handled asynchronously.
	const auto& cr = socket.cred();		const auto& cr = socket.cred();
	std::string error;		std::string error;
	uint32_t result = HandlePropertySet(name, value, source_context, cr, &socket, &error);		auto result = HandlePropertySet(name, value, source_context, cr, &socket, &error);
	if (result != PROP_SUCCESS) {		if (!result) {
			// Result will be sent after completion.
			return;
			}
			if (*result != PROP_SUCCESS) {
	LOG(ERROR) << "Unable to set property '" << name << "' from uid:" << cr.uid		LOG(ERROR) << "Unable to set property '" << name << "' from uid:" << cr.uid
	<< " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;		<< " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;
	}		}
	socket.SendUint32(result);		socket.SendUint32(*result);
	break;		break;
	}		}

	@@ -622,10 +680,9 @@ static void handle_property_set_fd() {
	}		}

	uint32_t InitPropertySet(const std::string& name, const std::string& value) {		uint32_t InitPropertySet(const std::string& name, const std::string& value) {
	uint32_t result = 0;
	ucred cr = {.pid = 1, .uid = 0, .gid = 0};		ucred cr = {.pid = 1, .uid = 0, .gid = 0};
	std::string error;		std::string error;
	result = HandlePropertySet(name, value, kInitContext, cr, nullptr, &error);		auto result = HandlePropertySetNoSocket(name, value, kInitContext, cr, &error);
	if (result != PROP_SUCCESS) {		if (result != PROP_SUCCESS) {
	LOG(ERROR) << "Init cannot set '" << name << "' to '" << value << "': " << error;		LOG(ERROR) << "Init cannot set '" << name << "' to '" << value << "': " << error;
	}		}
	@@ -795,7 +852,7 @@ static void load_override_properties() {
	load_properties_from_file("/data/local.prop", nullptr, &properties);		load_properties_from_file("/data/local.prop", nullptr, &properties);
	for (const auto& [name, value] : properties) {		for (const auto& [name, value] : properties) {
	std::string error;		std::string error;
	if (PropertySet(name, value, &error) != PROP_SUCCESS) {		if (PropertySetNoSocket(name, value, &error) != PROP_SUCCESS) {
	LOG(ERROR) << "Could not set '" << name << "' to '" << value		LOG(ERROR) << "Could not set '" << name << "' to '" << value
	<< "' in /data/local.prop: " << error;		<< "' in /data/local.prop: " << error;
	}		}
	@@ -861,7 +918,7 @@ static void property_initialize_ro_product_props() {
	LOG(INFO) << "Setting product property " << base_prop << " to '" << target_prop_val		LOG(INFO) << "Setting product property " << base_prop << " to '" << target_prop_val
	<< "' (from " << target_prop << ")";		<< "' (from " << target_prop << ")";
	std::string error;		std::string error;
	uint32_t res = PropertySet(base_prop, target_prop_val, &error);		auto res = PropertySetNoSocket(base_prop, target_prop_val, &error);
	if (res != PROP_SUCCESS) {		if (res != PROP_SUCCESS) {
	LOG(ERROR) << "Error setting product property " << base_prop << ": err=" << res		LOG(ERROR) << "Error setting product property " << base_prop << ": err=" << res
	<< " (" << error << ")";		<< " (" << error << ")";
	@@ -890,7 +947,7 @@ static void property_initialize_build_id() {
	}		}

	std::string error;		std::string error;
	auto res = PropertySet(ID_PROP, build_id, &error);		auto res = PropertySetNoSocket(ID_PROP, build_id, &error);
	if (res != PROP_SUCCESS) {		if (res != PROP_SUCCESS) {
	LOG(ERROR) << "Failed to set " << ID_PROP << " to " << build_id;		LOG(ERROR) << "Failed to set " << ID_PROP << " to " << build_id;
	}		}
	@@ -938,7 +995,7 @@ static void property_derive_legacy_build_fingerprint() {
	<< legacy_build_fingerprint << "'";		<< legacy_build_fingerprint << "'";

	std::string error;		std::string error;
	uint32_t res = PropertySet(LEGACY_FINGERPRINT_PROP, legacy_build_fingerprint, &error);		auto res = PropertySetNoSocket(LEGACY_FINGERPRINT_PROP, legacy_build_fingerprint, &error);
	if (res != PROP_SUCCESS) {		if (res != PROP_SUCCESS) {
	LOG(ERROR) << "Error setting property '" << LEGACY_FINGERPRINT_PROP << "': err=" << res		LOG(ERROR) << "Error setting property '" << LEGACY_FINGERPRINT_PROP << "': err=" << res
	<< " (" << error << ")";		<< " (" << error << ")";
	@@ -956,7 +1013,7 @@ static void property_derive_build_fingerprint() {
	LOG(INFO) << "Setting property '" << FINGERPRINT_PROP << "' to '" << build_fingerprint << "'";		LOG(INFO) << "Setting property '" << FINGERPRINT_PROP << "' to '" << build_fingerprint << "'";

	std::string error;		std::string error;
	uint32_t res = PropertySet(FINGERPRINT_PROP, build_fingerprint, &error);		auto res = PropertySetNoSocket(FINGERPRINT_PROP, build_fingerprint, &error);
	if (res != PROP_SUCCESS) {		if (res != PROP_SUCCESS) {
	LOG(ERROR) << "Error setting property '" << FINGERPRINT_PROP << "': err=" << res << " ("		LOG(ERROR) << "Error setting property '" << FINGERPRINT_PROP << "': err=" << res << " ("
	<< error << ")";		<< error << ")";
	@@ -1018,7 +1075,7 @@ static void property_initialize_ro_cpu_abilist() {
	LOG(INFO) << "Setting property '" << prop << "' to '" << prop_val << "'";		LOG(INFO) << "Setting property '" << prop << "' to '" << prop_val << "'";

	std::string error;		std::string error;
	uint32_t res = PropertySet(prop, prop_val, &error);		auto res = PropertySetNoSocket(prop, prop_val, &error);
	if (res != PROP_SUCCESS) {		if (res != PROP_SUCCESS) {
	LOG(ERROR) << "Error setting property '" << prop << "': err=" << res << " (" << error		LOG(ERROR) << "Error setting property '" << prop << "': err=" << res << " (" << error
	<< ")";		<< ")";
	@@ -1052,7 +1109,7 @@ static void property_initialize_ro_vendor_api_level() {
	int api_level = std::min(read_api_level_props(BOARD_API_LEVEL_PROPS),		int api_level = std::min(read_api_level_props(BOARD_API_LEVEL_PROPS),
	read_api_level_props(DEVICE_API_LEVEL_PROPS));		read_api_level_props(DEVICE_API_LEVEL_PROPS));
	std::string error;		std::string error;
	uint32_t res = PropertySet(VENDOR_API_LEVEL_PROP, std::to_string(api_level), &error);		auto res = PropertySetNoSocket(VENDOR_API_LEVEL_PROP, std::to_string(api_level), &error);
	if (res != PROP_SUCCESS) {		if (res != PROP_SUCCESS) {
	LOG(ERROR) << "Failed to set " << VENDOR_API_LEVEL_PROP << " with " << api_level << ": "		LOG(ERROR) << "Failed to set " << VENDOR_API_LEVEL_PROP << " with " << api_level << ": "
	<< error << "(" << res << ")";		<< error << "(" << res << ")";
	@@ -1146,7 +1203,7 @@ void PropertyLoadBootDefaults() {

	for (const auto& [name, value] : properties) {		for (const auto& [name, value] : properties) {
	std::string error;		std::string error;
	if (PropertySet(name, value, &error) != PROP_SUCCESS) {		if (PropertySetNoSocket(name, value, &error) != PROP_SUCCESS) {
	LOG(ERROR) << "Could not set '" << name << "' to '" << value		LOG(ERROR) << "Could not set '" << name << "' to '" << value
	<< "' while loading .prop files" << error;		<< "' while loading .prop files" << error;
	}		}
	@@ -1388,6 +1445,46 @@ static void PropertyServiceThread() {
	}		}
	}		}

			PersistWriteThread::PersistWriteThread() {
			auto new_thread = std::thread([this]() -> void { Work(); });
			thread_.swap(new_thread);
			}

			void PersistWriteThread::Work() {
			while (true) {
			std::tuple<std::string, std::string, SocketConnection> item;

			// Grab the next item within the lock.
			{
			std::unique_lock<std::mutex> lock(mutex_);

			while (work_.empty()) {
			cv_.wait(lock);
			}

			item = std::move(work_.front());
			work_.pop_front();
			}

			std::this_thread::sleep_for(1s);

			// Perform write/fsync outside the lock.
			WritePersistentProperty(std::get<0>(item), std::get<1>(item));
			NotifyPropertyChange(std::get<0>(item), std::get<1>(item));

			SocketConnection& socket = std::get<2>(item);
			socket.SendUint32(PROP_SUCCESS);
			}
			}

			void PersistWriteThread::Write(std::string name, std::string value, SocketConnection socket) {
			{
			std::unique_lock<std::mutex> lock(mutex_);
			work_.emplace_back(std::move(name), std::move(value), std::move(socket));
			}
			cv_.notify_all();
			}

	void StartPropertyService(int* epoll_socket) {		void StartPropertyService(int* epoll_socket) {
	InitPropertySet("ro.property_service.version", "2");		InitPropertySet("ro.property_service.version", "2");

	@@ -1412,6 +1509,13 @@ void StartPropertyService(int* epoll_socket) {

	auto new_thread = std::thread{PropertyServiceThread};		auto new_thread = std::thread{PropertyServiceThread};
	property_service_thread.swap(new_thread);		property_service_thread.swap(new_thread);

			auto async_persist_writes =
			android::base::GetBoolProperty("ro.property_service.async_persist_writes", false);

			if (async_persist_writes) {
			persist_write_thread = std::make_unique<PersistWriteThread>();
			}
	}		}

	} // namespace init		} // namespace init

init/property_service.h

+4 −0

Original line number	Original line	Diff line number	Diff line
	@@ -18,7 +18,11 @@

	#include <sys/socket.h>		#include <sys/socket.h>

			#include <condition_variable>
			#include <deque>
			#include <mutex>
	#include <string>		#include <string>
			#include <thread>

	#include "epoll.h"		#include "epoll.h"