init: fix signal handling and LOG(FATAL) in child processes
Child processes inherit the signal handlers and the 'Aborter' for
logging from their parent process. In the case of init, fork()'ed
processes, will attempt to reboot the system if they receive a fatal
signal or if they call LOG(FATAL). This is not the correct behavior;
these processes should terminate due to the provided signal like other
processes on the system.
This is particularly important as there are multiple LOG(FATAL) calls
in service.cpp for failures after fork() but before execv() when a
service is started.
Note, that pthread_atfork() is not a viable solution since clone() is
used in some cases instead of fork() and atfork handlers are not
called with clone().
Test: LOG(FATAL) from a child process of init and see that it
terminates due to a signal correctly
Test: LOG(FATAL) from init proper and see that it reboots to the
bootloader
Change-Id: I875ebd7a5f6b3f5e3e2c028af3306917c4409db3
diff --git a/init/log.cpp b/init/log.cpp
index 391bc1f..6198fc2 100644
--- a/init/log.cpp
+++ b/init/log.cpp
@@ -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 @@
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 @@
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, ...) {