From 52a2c6958beb2cb3ef63e8cf532a386413dc78ba Mon Sep 17 00:00:00 2001
From: topjohnwu <topjohnwu@gmail.com>
Date: Tue, 3 Jul 2018 22:25:39 +0800
Subject: [PATCH] Optimize log daemon

---
 native/jni/core/log_monitor.c | 57 +++++++++++++----------------------
 1 file changed, 21 insertions(+), 36 deletions(-)

diff --git a/native/jni/core/log_monitor.c b/native/jni/core/log_monitor.c
index 8f8de7777..fb9971120 100644
--- a/native/jni/core/log_monitor.c
+++ b/native/jni/core/log_monitor.c
@@ -17,7 +17,6 @@
 
 int loggable = 1;
 static int sockfd;
-static pthread_t thread = -1;
 static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
 
 enum {
@@ -38,7 +37,7 @@ static int magisk_log_filter(const char *log) {
 	return !am_proc_start_filter(log);
 }
 
-static struct log_listener log_events[] = {
+static struct log_listener events[] = {
 	{	/* HIDE_EVENT */
 		.fd = -1,
 		.filter = am_proc_start_filter
@@ -48,7 +47,7 @@ static struct log_listener log_events[] = {
 		.filter = magisk_log_filter
 	}
 };
-#define EVENT_NUM (sizeof(log_events) / sizeof(struct log_listener))
+#define EVENT_NUM (sizeof(events) / sizeof(struct log_listener))
 
 static void test_logcat() {
 	int log_fd = -1, log_pid;
@@ -56,28 +55,28 @@ static void test_logcat() {
 	log_pid = exec_command(0, &log_fd, NULL, "logcat", NULL);
 	if (read(log_fd, buf, sizeof(buf)) != sizeof(buf)) {
 		loggable = 0;
-		LOGD("log_monitor: cannot read from logcat, disable logging");
+		LOGD("magisklogd: cannot read from logcat, disable logging");
 	}
 	kill(log_pid, SIGTERM);
 	waitpid(log_pid, NULL, 0);
 }
 
 static void sigpipe_handler(int sig) {
-	close(log_events[HIDE_EVENT].fd);
-	log_events[HIDE_EVENT].fd = -1;
+	close(events[HIDE_EVENT].fd);
+	events[HIDE_EVENT].fd = -1;
 }
 
 static void *socket_thread(void *args) {
 	/* This would block, so separate thread */
 	while(1) {
-		int fd = accept4(sockfd, NULL, NULL, SOCK_CLOEXEC);
+		int fd = xaccept4(sockfd, NULL, NULL, SOCK_CLOEXEC);
 		switch(read_int(fd)) {
 			case HIDE_CONNECT:
 				pthread_mutex_lock(&lock);
-				log_events[HIDE_EVENT].fd = fd;
+				close(events[HIDE_EVENT].fd);
+				events[HIDE_EVENT].fd = fd;
 				pthread_mutex_unlock(&lock);
-				thread = -1;
-				return NULL;
+				break;
 			default:
 				close(fd);
 				break;
@@ -107,20 +106,20 @@ static void *monitor_thread(void *args) {
 
 void log_daemon() {
 	setsid();
-	strcpy(argv0, "magisklogd");
-
 	struct sockaddr_un sun;
 	sockfd = setup_socket(&sun, LOG_DAEMON);
 	if (xbind(sockfd, (struct sockaddr*) &sun, sizeof(sun)))
 		exit(1);
-	xlisten(sockfd, 1);
+	xlisten(sockfd, 10);
 	LOGI("Magisk v" xstr(MAGISK_VERSION) "(" xstr(MAGISK_VER_CODE) ") logger started\n");
+	strcpy(argv0, "magisklogd");
 
-	// Start invincible mode monitor
-	// TODO: Remove this when all crashes are fixed
+	// Start worker threads
 	pthread_t t;
 	pthread_create(&t, NULL, monitor_thread, NULL);
 	pthread_detach(t);
+	xpthread_create(&t, NULL, socket_thread, NULL);
+	pthread_detach(t);
 
 	// Set SIGPIPE handler
 	struct sigaction act;
@@ -130,21 +129,12 @@ void log_daemon() {
 
 	// Setup log dumps
 	rename(LOGFILE, LOGFILE ".bak");
-	log_events[LOG_EVENT].fd = xopen(LOGFILE, O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, 0644);
+	events[LOG_EVENT].fd = xopen(LOGFILE, O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, 0644);
 
 	int log_fd = -1, log_pid;
 	char line[PIPE_BUF];
 
 	while (1) {
-		if (!loggable) {
-			// Disable all services
-			for (int i = 0; i < EVENT_NUM; ++i) {
-				close(log_events[i].fd);
-				log_events[i].fd = -1;
-			}
-			return;
-		}
-
 		// Start logcat
 		log_pid = exec_command(0, &log_fd, NULL,
 							   "/system/bin/logcat",
@@ -159,25 +149,20 @@ void log_daemon() {
 			size_t len = strlen(line);
 			pthread_mutex_lock(&lock);
 			for (int i = 0; i < EVENT_NUM; ++i) {
-				if (log_events[i].fd > 0 && log_events[i].filter(line))
-					write(log_events[i].fd, line, len);
-			}
-			if (thread < 0 && log_events[HIDE_EVENT].fd < 0) {
-				// New thread to handle connection to main daemon
-				xpthread_create(&thread, NULL, socket_thread, NULL);
-				pthread_detach(thread);
+				if (events[i].fd > 0 && events[i].filter(line))
+					write(events[i].fd, line, len);
 			}
 			pthread_mutex_unlock(&lock);
-			if (kill(log_pid, 0))
-				break;
 		}
 
-		// Cleanup
 		fclose(logs);
 		log_fd = -1;
 		kill(log_pid, SIGTERM);
 		waitpid(log_pid, NULL, 0);
-		test_logcat();
+
+		LOGI("magisklogd: logcat output EOF");
+		// Clear buffer
+		exec_command_sync("logcat", "-b", "events", "-b", "main", "-b", "crash", "-c", NULL);
 	}
 }