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Merge "init: fix signal handling and LOG(FATAL) in child processes"

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Tom Cherry 2017-08-28 21:45:38 +00:00 committed by Gerrit Code Review
commit 30bf4b7500
2 changed files with 20 additions and 6 deletions
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12
init/init.cpp
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@ -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);

14
init/log.cpp
View file

@ -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, ...) {