Optimize magiskhide to work with the log daemon

native/jni/magiskhide/hide_utils.c

@@ -26,21 +26,15 @@ static char *prop_value[] =
 	  "0", "0", "0", "1",
 	  "user", "release-keys", "0", NULL };
 
-static int mocked = 0;
-
 void manage_selinux() {
-	if (mocked) return;
-	char val[1];
+	char val;
 	int fd = xopen(SELINUX_ENFORCE, O_RDONLY);
-	xxread(fd, val, 1);
+	xxread(fd, &val, sizeof(val));
 	close(fd);
 	// Permissive
-	if (val[0] == '0') {
-		LOGI("hide_daemon: Permissive detected, hide the state\n");
-
+	if (val == '0') {
 		chmod(SELINUX_ENFORCE, 0640);
 		chmod(SELINUX_POLICY, 0440);
-		mocked = 1;
 	}
 }
 
@@ -65,6 +59,10 @@ static void rm_magisk_prop(const char *name, const char *value, void *v) {
 	}
 }
 
+static void kill_proc(int pid) {
+	kill(pid, SIGTERM);
+}
+
 void clean_magisk_props() {
 	LOGD("hide_utils: Cleaning magisk props\n");
 	getprop_all(rm_magisk_prop, NULL);

native/jni/magiskhide/magiskhide.c

@@ -22,10 +22,6 @@ int hideEnabled = 0;
 static pthread_t proc_monitor_thread;
 pthread_mutex_t hide_lock, file_lock;
 
-void kill_proc(int pid) {
-	kill(pid, SIGTERM);
-}
-
 static void usage(char *arg0) {
 	fprintf(stderr,
 		"MagiskHide v" xstr(MAGISK_VERSION) "(" xstr(MAGISK_VER_CODE) ") (by topjohnwu) - Hide Magisk!\n\n"

native/jni/magiskhide/magiskhide.h

@@ -5,9 +5,6 @@
 
 #define TERM_THREAD SIGUSR1
 
-// Kill process
-void kill_proc(int pid);
-
 // Process monitor
 void proc_monitor();
 

native/jni/magiskhide/proc_monitor.c

@@ -126,18 +126,16 @@ void proc_monitor() {
 		term_thread(TERM_THREAD);
 	}
 
+	while(1) {
 		// Connect to the log daemon
 		connect_daemon2(LOG_DAEMON, &sockfd);
 		write_int(sockfd, HIDE_CONNECT);
 
-	FILE *logs = fdopen(sockfd, "r");
-	char log[4096], *line;
-	while (1) {
-		/* It might be interrupted */
-		if (fgets(log, sizeof(log), logs) == NULL)
-			continue;
-		char *ss = strchr(log, '[');
-		int pid, ppid, ret, comma = 0;
+		FILE *log_in = fdopen(sockfd, "r");
+		char buf[4096];
+		while (fgets(buf, sizeof(buf), log_in)) {
+			char *ss = strchr(buf, '[');
+			int pid, ppid, num = 0;
 			char *pos = ss, proc[256], ns[32], pns[32];
 
 			while(1) {
@@ -145,28 +143,35 @@ void proc_monitor() {
 				if(pos == NULL)
 					break;
 				pos[0] = ' ';
-			++comma;
+				++num;
 			}
 
-		if (comma == 6)
-			ret = sscanf(ss, "[%*d %d %*d %*d %256s", &pid, proc);
-		else
-			ret = sscanf(ss, "[%*d %d %*d %256s", &pid, proc);
-
-		if(ret != 2)
+			if(sscanf(ss, num == 6 ? "[%*d %d %*d %*d %256s" : "[%*d %d %*d %256s", &pid, proc) != 2)
 				continue;
 
-		ppid = parse_ppid(pid);
+			// Make sure our target is alive
+			if (kill(pid, 0))
+				continue;
 
 			// Allow hiding sub-services of applications
 			char *colon = strchr(proc, ':');
 			if (colon)
 				*colon = '\0';
 
-		// Critical region
+			int hide = 0;
 			pthread_mutex_lock(&hide_lock);
+			char *line;
 			vec_for_each(hide_list, line) {
 				if (strcmp(proc, line) == 0) {
+					hide = 1;
+					break;
+				}
+			}
+			pthread_mutex_unlock(&hide_lock);
+			if (!hide)
+				continue;
+
+			ppid = parse_ppid(pid);
 			read_namespace(ppid, pns, sizeof(pns));
 			do {
 				read_namespace(pid, ns, sizeof(ns));
@@ -184,7 +189,8 @@ void proc_monitor() {
 			if (colon)
 				*colon = ':';
 #ifdef MAGISK_DEBUG
-				LOGI("proc_monitor: %s (PID=[%d] ns=%s)(PPID=[%d] ns=%s)\n", proc, pid, ns + 4, ppid, pns + 4);
+			LOGI("proc_monitor: %s (PID=[%d] ns=%s)(PPID=[%d] ns=%s)\n",
+				 proc, pid, ns + 4, ppid, pns + 4);
 #else
 			LOGI("proc_monitor: %s\n", proc);
 #endif
@@ -195,10 +201,7 @@ void proc_monitor() {
 			 */
 			if (fork_dont_care() == 0)
 				hide_daemon(pid);
-
-				break;
-			}
-		}
-		pthread_mutex_unlock(&hide_lock);
+		}
+		// The other end EOF, restart the connection
 	}
 }

native/jni/utils/misc.c

@@ -170,22 +170,38 @@ void ps(void (*func)(int)) {
 static void (*ps_filter_cb)(int);
 static const char *ps_filter_pattern;
 static void proc_name_filter(int pid) {
-	char buf[64];
-	int fd;
-	snprintf(buf, sizeof(buf), "/proc/%d/cmdline", pid);
-	if (access(buf, R_OK) == -1 || (fd = xopen(buf, O_RDONLY)) == -1)
+	char buf[128];
+	FILE *f;
+	sprintf(buf, "/proc/%d/comm", pid);
+	if ((f = fopen(buf, "r"))) {
+		fgets(buf, sizeof(buf), f);
+		if (strcmp(buf, ps_filter_pattern) == 0)
+			goto run_cb;
+	} else {
+		// The PID is already killed
 		return;
-	if (fdgets(buf, sizeof(buf), fd) == 0) {
-		snprintf(buf, sizeof(buf), "/proc/%d/comm", pid);
-		close(fd);
-		if (access(buf, R_OK) == -1 || (fd = xopen(buf, O_RDONLY)) == -1)
-			return;
-		fdgets(buf, sizeof(buf), fd);
 	}
-	if (strcmp(buf, ps_filter_pattern) == 0) {
+	fclose(f);
+
+	sprintf(buf, "/proc/%d/cmdline", pid);
+	f = fopen(buf, "r");
+	fgets(buf, sizeof(buf), f);
+	if (strcmp(basename(buf), ps_filter_pattern) == 0)
+		goto run_cb;
+	fclose(f);
+
+	sprintf(buf, "/proc/%d/exe", pid);
+	if (access(buf, F_OK) != 0)
+		return;
+	xreadlink(buf, buf, sizeof(buf));
+	if (strcmp(basename(buf), ps_filter_pattern) == 0)
+		goto run_cb;
+
+	return;
+run_cb:
 	ps_filter_cb(pid);
-	}
-	close(fd);
+	fclose(f);
+	return;
 }
 
 /* Call func with process name filtered with pattern */