init: move reaping from ServiceManager to signal_handler.cpp (eeee8310) · Commits · e / os / android_system_core

init/reboot.cpp

+3 −2

Original line number	Diff line number	Diff line
		@@ -53,6 +53,7 @@
		#include "init.h"
		#include "property_service.h"
		#include "service.h"
		#include "signal_handler.h"

		using android::base::StringPrintf;
		using android::base::Timer;
		@@ -406,7 +407,7 @@ void DoReboot(unsigned int cmd, const std::string& reason, const std::string& re
		// Only wait up to half of timeout here
		auto termination_wait_timeout = shutdown_timeout / 2;
		while (t.duration() < termination_wait_timeout) {
		ServiceManager::GetInstance().ReapAnyOutstandingChildren();
		ReapAnyOutstandingChildren();

		service_count = 0;
		ServiceManager::GetInstance().ForEachService([&service_count](Service* s) {
		@@ -437,7 +438,7 @@ void DoReboot(unsigned int cmd, const std::string& reason, const std::string& re
		ServiceManager::GetInstance().ForEachServiceShutdownOrder([](Service* s) {
		if (!s->IsShutdownCritical()) s->Stop();
		});
		ServiceManager::GetInstance().ReapAnyOutstandingChildren();
		ReapAnyOutstandingChildren();

		// 3. send volume shutdown to vold
		Service* voldService = ServiceManager::GetInstance().FindServiceByName("vold");

init/service.cpp

+0 −63

Original line number	Diff line number	Diff line
		@@ -1091,69 +1091,6 @@ void ServiceManager::DumpState() const {
		}
		}

		bool ServiceManager::ReapOneProcess() {
		siginfo_t siginfo = {};
		// This returns a zombie pid or informs us that there are no zombies left to be reaped.
		// It does NOT reap the pid; that is done below.
		if (TEMP_FAILURE_RETRY(waitid(P_ALL, 0, &siginfo, WEXITED \| WNOHANG \| WNOWAIT)) != 0) {
		PLOG(ERROR) << "waitid failed";
		return false;
		}

		auto pid = siginfo.si_pid;
		if (pid == 0) return false;

		// At this point we know we have a zombie pid, so we use this scopeguard to reap the pid
		// whenever the function returns from this point forward.
		// We do NOT want to reap the zombie earlier as in Service::Reap(), we kill(-pid, ...) and we
		// want the pid to remain valid throughout that (and potentially future) usages.
		auto reaper = make_scope_guard([pid] { TEMP_FAILURE_RETRY(waitpid(pid, nullptr, WNOHANG)); });

		if (PropertyChildReap(pid)) {
		return true;
		}

		Service* svc = FindServiceByPid(pid);

		std::string name;
		std::string wait_string;
		if (svc) {
		name = StringPrintf("Service '%s' (pid %d)", svc->name().c_str(), pid);
		if (svc->flags() & SVC_EXEC) {
		auto exec_duration = boot_clock::now() - svc->time_started();
		auto exec_duration_ms =
		std::chrono::duration_cast<std::chrono::milliseconds>(exec_duration).count();
		wait_string = StringPrintf(" waiting took %f seconds", exec_duration_ms / 1000.0f);
		}
		} else {
		name = StringPrintf("Untracked pid %d", pid);
		}

		auto status = siginfo.si_status;
		if (WIFEXITED(status)) {
		LOG(INFO) << name << " exited with status " << WEXITSTATUS(status) << wait_string;
		} else if (WIFSIGNALED(status)) {
		LOG(INFO) << name << " killed by signal " << WTERMSIG(status) << wait_string;
		}

		if (!svc) {
		return true;
		}

		svc->Reap();

		if (svc->flags() & SVC_TEMPORARY) {
		RemoveService(*svc);
		}

		return true;
		}

		void ServiceManager::ReapAnyOutstandingChildren() {
		while (ReapOneProcess()) {
		}
		}

		bool ServiceParser::ParseSection(std::vector<std::string>&& args, const std::string& filename,
		int line, std::string* err) {
		if (args.size() < 3) {

init/service.h

+0 −5

Original line number	Diff line number	Diff line
		@@ -221,15 +221,10 @@ class ServiceManager {
		void ForEachServiceShutdownOrder(const std::function<void(Service*)>& callback) const;
		void ForEachServiceInClass(const std::string& classname,
		void (func)(Service svc)) const;
		void ReapAnyOutstandingChildren();
		void RemoveService(const Service& svc);
		void DumpState() const;

		private:
		// Cleans up a child process that exited.
		// Returns true iff a children was cleaned up.
		bool ReapOneProcess();

		std::vector<std::unique_ptr<Service>> services_;
		};

init/signal_handler.cpp

+72 −2

Original line number	Diff line number	Diff line
		@@ -14,29 +14,94 @@
		* limitations under the License.
		*/

		#include "signal_handler.h"

		#include <signal.h>
		#include <string.h>
		#include <sys/socket.h>
		#include <sys/types.h>
		#include <sys/wait.h>
		#include <unistd.h>

		#include <android-base/chrono_utils.h>
		#include <android-base/logging.h>
		#include <android-base/scopeguard.h>
		#include <android-base/stringprintf.h>

		#include "init.h"
		#include "property_service.h"
		#include "service.h"

		using android::base::StringPrintf;
		using android::base::boot_clock;
		using android::base::make_scope_guard;

		namespace android {
		namespace init {

		static int signal_write_fd = -1;
		static int signal_read_fd = -1;

		static bool ReapOneProcess() {
		siginfo_t siginfo = {};
		// This returns a zombie pid or informs us that there are no zombies left to be reaped.
		// It does NOT reap the pid; that is done below.
		if (TEMP_FAILURE_RETRY(waitid(P_ALL, 0, &siginfo, WEXITED \| WNOHANG \| WNOWAIT)) != 0) {
		PLOG(ERROR) << "waitid failed";
		return false;
		}

		auto pid = siginfo.si_pid;
		if (pid == 0) return false;

		// At this point we know we have a zombie pid, so we use this scopeguard to reap the pid
		// whenever the function returns from this point forward.
		// We do NOT want to reap the zombie earlier as in Service::Reap(), we kill(-pid, ...) and we
		// want the pid to remain valid throughout that (and potentially future) usages.
		auto reaper = make_scope_guard([pid] { TEMP_FAILURE_RETRY(waitpid(pid, nullptr, WNOHANG)); });

		if (PropertyChildReap(pid)) return true;

		Service* service = ServiceManager::GetInstance().FindServiceByPid(pid);

		std::string name;
		std::string wait_string;
		if (service) {
		name = StringPrintf("Service '%s' (pid %d)", service->name().c_str(), pid);
		if (service->flags() & SVC_EXEC) {
		auto exec_duration = boot_clock::now() - service->time_started();
		auto exec_duration_ms =
		std::chrono::duration_cast<std::chrono::milliseconds>(exec_duration).count();
		wait_string = StringPrintf(" waiting took %f seconds", exec_duration_ms / 1000.0f);
		}
		} else {
		name = StringPrintf("Untracked pid %d", pid);
		}

		auto status = siginfo.si_status;
		if (WIFEXITED(status)) {
		LOG(INFO) << name << " exited with status " << WEXITSTATUS(status) << wait_string;
		} else if (WIFSIGNALED(status)) {
		LOG(INFO) << name << " killed by signal " << WTERMSIG(status) << wait_string;
		}

		if (!service) return true;

		service->Reap();

		if (service->flags() & SVC_TEMPORARY) {
		ServiceManager::GetInstance().RemoveService(*service);
		}

		return true;
		}

		static void handle_signal() {
		// Clear outstanding requests.
		char buf[32];
		read(signal_read_fd, buf, sizeof(buf));

		ServiceManager::GetInstance().ReapAnyOutstandingChildren();
		ReapAnyOutstandingChildren();
		}

		static void SIGCHLD_handler(int) {
		@@ -45,6 +110,11 @@ static void SIGCHLD_handler(int) {
		}
		}

		void ReapAnyOutstandingChildren() {
		while (ReapOneProcess()) {
		}
		}

		void signal_handler_init() {
		// Create a signalling mechanism for SIGCHLD.
		int s[2];
		@@ -63,7 +133,7 @@ void signal_handler_init() {
		act.sa_flags = SA_NOCLDSTOP;
		sigaction(SIGCHLD, &act, 0);

		ServiceManager::GetInstance().ReapAnyOutstandingChildren();
		ReapAnyOutstandingChildren();

		register_epoll_handler(signal_read_fd, handle_signal);
		}

init/signal_handler.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -20,6 +20,8 @@
		namespace android {
		namespace init {

		void ReapAnyOutstandingChildren();

		void signal_handler_init(void);

		} // namespace init