Merge "Clean up init signal handling a little." (b749be0b) · Commits · e / os / android_system_core

init/init.cpp

+3 −21

Original line number	Diff line number	Diff line
		@@ -848,16 +848,6 @@ static int property_service_init_action(int nargs, char **args)
		return 0;
		}

		static int signal_init_action(int nargs, char **args)
		{
		signal_init();
		if (get_signal_fd() < 0) {
		ERROR("signal_init() failed\n");
		exit(1);
		}
		return 0;
		}

		static int queue_property_triggers_action(int nargs, char **args)
		{
		queue_all_property_triggers();
		@@ -1061,13 +1051,12 @@ int main(int argc, char** argv) {
		restorecon("/dev/__properties__");
		restorecon_recursive("/sys");

		signal_init();

		property_load_boot_defaults();

		init_parse_config_file("/init.rc");

		// Setup signal handler before any exec command or we'll deadlock
		queue_builtin_action(signal_init_action, "signal_init");

		action_for_each_trigger("early-init", action_add_queue_tail);

		queue_builtin_action(wait_for_coldboot_done_action, "wait_for_coldboot_done");
		@@ -1097,8 +1086,8 @@ int main(int argc, char** argv) {
		// TODO: why do we only initialize ufds after execute_one_command and restart_processes?
		size_t fd_count = 0;
		struct pollfd ufds[3];
		ufds[fd_count++] = { .fd = get_signal_fd(), .events = POLLIN, .revents = 0 };
		bool property_set_fd_init = false;
		bool signal_fd_init = false;
		bool keychord_fd_init = false;

		for (;;) {
		@@ -1114,13 +1103,6 @@ int main(int argc, char** argv) {
		fd_count++;
		property_set_fd_init = true;
		}
		if (!signal_fd_init && get_signal_fd() > 0) {
		ufds[fd_count].fd = get_signal_fd();
		ufds[fd_count].events = POLLIN;
		ufds[fd_count].revents = 0;
		fd_count++;
		signal_fd_init = true;
		}
		if (!keychord_fd_init && get_keychord_fd() > 0) {
		ufds[fd_count].fd = get_keychord_fd();
		ufds[fd_count].events = POLLIN;

init/signal_handler.cpp

+43 −29

Original line number	Diff line number	Diff line
		@@ -35,14 +35,10 @@
		#define CRITICAL_CRASH_THRESHOLD 4 /* if we crash >4 times ... */
		#define CRITICAL_CRASH_WINDOW (460) / ... in 4 minutes, goto recovery */

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

		static void sigchld_handler(int s) {
		write(signal_fd, &s, 1);
		}

		std::string DescribeStatus(int status) {
		static std::string DescribeStatus(int status) {
		if (WIFEXITED(status)) {
		return android::base::StringPrintf("exited with status %d", WEXITSTATUS(status));
		} else if (WIFSIGNALED(status)) {
		@@ -54,11 +50,14 @@ std::string DescribeStatus(int status) {
		}
		}

		static int wait_for_one_process() {
		static bool wait_for_one_process() {
		int status;
		pid_t pid = TEMP_FAILURE_RETRY(waitpid(-1, &status, WNOHANG));
		if (pid <= 0) {
		return -1;
		if (pid == 0) {
		return false;
		} else if (pid == -1) {
		ERROR("waitpid failed: %s\n", strerror(errno));
		return false;
		}

		service* svc = service_find_by_pid(pid);
		@@ -73,7 +72,7 @@ static int wait_for_one_process() {
		NOTICE("%s %s\n", name.c_str(), DescribeStatus(status).c_str());

		if (!svc) {
		return 0;
		return true;
		}

		// TODO: all the code from here down should be a member function on service.
		@@ -96,7 +95,7 @@ static int wait_for_one_process() {
		list_remove(&svc->slist);
		free(svc->name);
		free(svc);
		return 0;
		return true;
		}

		svc->pid = 0;
		@@ -111,7 +110,7 @@ static int wait_for_one_process() {
		// Disabled and reset processes do not get restarted automatically.
		if (svc->flags & (SVC_DISABLED \| SVC_RESET)) {
		svc->NotifyStateChange("stopped");
		return 0;
		return true;
		}

		time_t now = gettime();
		@@ -122,7 +121,7 @@ static int wait_for_one_process() {
		"rebooting into recovery mode\n", svc->name,
		CRITICAL_CRASH_THRESHOLD, CRITICAL_CRASH_WINDOW / 60);
		android_reboot(ANDROID_RB_RESTART2, 0, "recovery");
		return 0;
		return true;
		}
		} else {
		svc->time_crashed = now;
		@@ -140,34 +139,49 @@ static int wait_for_one_process() {
		cmd->func(cmd->nargs, cmd->args);
		}
		svc->NotifyStateChange("restarting");
		return 0;
		return true;
		}

		static void reap_any_outstanding_children() {
		while (wait_for_one_process()) {
		}
		}

		void handle_signal() {
		// We got a SIGCHLD - reap and restart as needed.
		char tmp[32];
		read(signal_recv_fd, tmp, sizeof(tmp));
		while (!wait_for_one_process()) {
		// Clear outstanding requests.
		char buf[32];
		read(signal_read_fd, buf, sizeof(buf));

		reap_any_outstanding_children();
		}

		static void SIGCHLD_handler(int) {
		if (TEMP_FAILURE_RETRY(write(signal_write_fd, "1", 1)) == -1) {
		ERROR("write(signal_write_fd) failed: %s\n", strerror(errno));
		}
		}

		void signal_init() {
		// Create a signalling mechanism for SIGCHLD.
		int s[2];
		if (socketpair(AF_UNIX, SOCK_STREAM \| SOCK_NONBLOCK \| SOCK_CLOEXEC, 0, s) == -1) {
		ERROR("socketpair failed: %s\n", strerror(errno));
		exit(1);
		}

		signal_write_fd = s[0];
		signal_read_fd = s[1];

		// Write to signal_write_fd if we catch SIGCHLD.
		struct sigaction act;
		memset(&act, 0, sizeof(act));
		act.sa_handler = sigchld_handler;
		act.sa_handler = SIGCHLD_handler;
		act.sa_flags = SA_NOCLDSTOP;
		sigaction(SIGCHLD, &act, 0);

		// Create a signalling mechanism for the sigchld handler.
		int s[2];
		if (socketpair(AF_UNIX, SOCK_STREAM \| SOCK_NONBLOCK \| SOCK_CLOEXEC, 0, s) == 0) {
		signal_fd = s[0];
		signal_recv_fd = s[1];
		}

		handle_signal();
		reap_any_outstanding_children();
		}

		int get_signal_fd() {
		return signal_recv_fd;
		return signal_read_fd;
		}