Merge "init: fix signal handling and LOG(FATAL) in child processes" (30bf4b75) · Commits · e / os / android_system_core

init/init.cpp

+9 −3

Original line number	Diff line number	Diff line
		@@ -358,7 +358,7 @@ static void set_usb_controller() {
		}
		}

		static void install_reboot_signal_handlers() {
		static void InstallRebootSignalHandlers() {
		// Instead of panic'ing the kernel as is the default behavior when init crashes,
		// we prefer to reboot to bootloader on development builds, as this will prevent
		// boot looping bad configurations and allow both developers and test farms to easily
		@@ -366,7 +366,13 @@ static void install_reboot_signal_handlers() {
		struct sigaction action;
		memset(&action, 0, sizeof(action));
		sigfillset(&action.sa_mask);
		action.sa_handler = [](int) {
		action.sa_handler = [](int signal) {
		// These signal handlers are also caught for processes forked from init, however we do not
		// want them to trigger reboot, so we directly call _exit() for children processes here.
		if (getpid() != 1) {
		_exit(signal);
		}

		// Calling DoReboot() or LOG(FATAL) is not a good option as this is a signal handler.
		// RebootSystem uses syscall() which isn't actually async-signal-safe, but our only option
		// and probably good enough given this is already an error case and only enabled for
		@@ -396,7 +402,7 @@ int main(int argc, char** argv) {
		}

		if (REBOOT_BOOTLOADER_ON_PANIC) {
		install_reboot_signal_handlers();
		InstallRebootSignalHandlers();
		}

		bool is_first_stage = (getenv("INIT_SECOND_STAGE") == nullptr);

+11 −3

Original line number	Diff line number	Diff line
		@@ -19,6 +19,7 @@
		#include <fcntl.h>
		#include <linux/audit.h>
		#include <string.h>
		#include <unistd.h>

		#include <android-base/logging.h>
		#include <cutils/android_reboot.h>
		@@ -29,7 +30,14 @@
		namespace android {
		namespace init {

		static void RebootAborter(const char* abort_message) {
		static void InitAborter(const char* abort_message) {
		// When init forks, it continues to use this aborter for LOG(FATAL), but we want children to
		// simply abort instead of trying to reboot the system.
		if (getpid() != 1) {
		android::base::DefaultAborter(abort_message);
		return;
		}

		// DoReboot() does a lot to try to shutdown the system cleanly. If something happens to call
		// LOG(FATAL) in the shutdown path, we want to catch this and immediately use the syscall to
		// reboot instead of recursing here.
		@@ -49,7 +57,7 @@ void InitKernelLogging(char* argv[]) {
		int fd = open("/sys/fs/selinux/null", O_RDWR);
		if (fd == -1) {
		int saved_errno = errno;
		android::base::InitLogging(argv, &android::base::KernelLogger, RebootAborter);
		android::base::InitLogging(argv, &android::base::KernelLogger, InitAborter);
		errno = saved_errno;
		PLOG(FATAL) << "Couldn't open /sys/fs/selinux/null";
		}
		@@ -58,7 +66,7 @@ void InitKernelLogging(char* argv[]) {
		dup2(fd, 2);
		if (fd > 2) close(fd);

		android::base::InitLogging(argv, &android::base::KernelLogger, RebootAborter);
		android::base::InitLogging(argv, &android::base::KernelLogger, InitAborter);
		}

		int selinux_klog_callback(int type, const char *fmt, ...) {