Invincible mode implemented in magisklogd

native/jni/core/bootstages.c

@@ -662,7 +662,7 @@ void startup() {
 	}
 
 	// Start post-fs-data mode
-	execl("/sbin/magisk", "magisk", "--post-fs-data", NULL);
+	execl("/sbin/magisk.bin", "magisk", "--post-fs-data", NULL);
 }
 
 void post_fs_data(int client) {

native/jni/core/daemon.c

@@ -83,6 +83,9 @@ static void *request_handler(void *args) {
 	case LATE_START:
 		late_start(client);
 		break;
+	case MONITOR:
+		/* Do NOT close the client, make it hold */
+		break;
 	default:
 		close(client);
 		break;
@@ -117,13 +120,6 @@ void main_daemon() {
 	xdup2(fd, STDIN_FILENO);
 	close(fd);
 
-	// Block user signals
-	sigset_t block_set;
-	sigemptyset(&block_set);
-	sigaddset(&block_set, SIGUSR1);
-	sigaddset(&block_set, SIGUSR2);
-	pthread_sigmask(SIG_SETMASK, &block_set, NULL);
-
 	// Start the log monitor
 	monitor_logs();
 
@@ -138,6 +134,19 @@ void main_daemon() {
 	// Change process name
 	strcpy(argv0, "magiskd");
 
+	// Block all user signals
+	sigset_t block_set;
+	sigemptyset(&block_set);
+	sigaddset(&block_set, SIGUSR1);
+	sigaddset(&block_set, SIGUSR2);
+	pthread_sigmask(SIG_SETMASK, &block_set, NULL);
+
+	// Ignore SIGPIPE
+	struct sigaction act;
+	memset(&act, 0, sizeof(act));
+	act.sa_handler = SIG_IGN;
+	sigaction(SIGPIPE, &act, NULL);
+
 	// Loop forever to listen for requests
 	while(1) {
 		int *client = xmalloc(sizeof(int));

native/jni/core/log_monitor.c

@@ -85,6 +85,26 @@ static void *socket_thread(void *args) {
 	}
 }
 
+static void *monitor_thread(void *args) {
+	// Block SIGPIPE to prevent interruption
+	sigset_t block_set;
+	sigemptyset(&block_set);
+	sigaddset(&block_set, SIGPIPE);
+	pthread_sigmask(SIG_SETMASK, &block_set, NULL);
+	// Give the main daemon some time before we monitor it
+	sleep(5);
+	int fd;
+	char b[1];
+	do {
+		fd = connect_daemon();
+		write_int(fd, MONITOR);
+		// This should hold unless the daemon is killed
+		read(fd, b, sizeof(b));
+		// The main daemon crashed, spawn a new one
+		close(fd);
+	} while (1);
+}
+
 void log_daemon() {
 	setsid();
 	strcpy(argv0, "magisklogd");
@@ -96,6 +116,13 @@ void log_daemon() {
 	xlisten(sockfd, 1);
 	LOGI("Magisk v" xstr(MAGISK_VERSION) "(" xstr(MAGISK_VER_CODE) ") logger started\n");
 
+	// Start invincible mode monitor
+	// TODO: Remove this when all crashes are fixed
+	pthread_t t;
+	pthread_create(&t, NULL, monitor_thread, NULL);
+	pthread_detach(t);
+
+	// Set SIGPIPE handler
 	struct sigaction act;
 	memset(&act, 0, sizeof(act));
 	act.sa_handler = sigpipe_handler;

native/jni/include/daemon.h

@@ -25,6 +25,7 @@ enum {
 	ADD_HIDELIST,
 	RM_HIDELIST,
 	LS_HIDELIST,
+	MONITOR,
 	HIDE_CONNECT
 };
 

native/jni/su

@@ -1 +1 @@
-Subproject commit ead8c03a3a6eed6621ffcf4bc2fd12429da3596e
+Subproject commit 69b226b005e3f87c4c872fa3382e05006969118e