Remove magisklogd, use threads and BlockingQueue

native/jni/core/logcat.cpp

@@ -0,0 +1,125 @@
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <signal.h>
+#include <vector>
+
+#include <logcat.h>
+#include <utils.h>
+#include <logging.h>
+#include <magisk.h>
+
+static std::vector<const char *> log_cmd, clear_cmd;
+static pthread_mutex_t event_lock = PTHREAD_MUTEX_INITIALIZER;
+bool logcat_started = false;
+
+struct log_listener {
+	bool enable = false;
+	BlockingQueue<std::string> queue;
+	bool (*filter)(const char *);
+};
+
+static struct log_listener events[] = {
+	{	/* HIDE_EVENT */
+		.filter = [](auto log) -> bool { return strstr(log, "am_proc_start") != nullptr; }
+	},
+	{	/* LOG_EVENT */
+		.filter = [](auto log) -> bool { return !strstr(log, "am_proc_start"); }
+	}
+};
+
+static void init_args() {
+	// Construct cmdline
+	log_cmd.push_back(MIRRDIR "/system/bin/logcat");
+	// Test whether these buffers actually works
+	const char *b[] = { "main", "events", "crash" };
+	for (auto &buffer : b) {
+		if (exec_command_sync(MIRRDIR "/system/bin/logcat", "-b", buffer, "-d", "-f", "/dev/null") == 0) {
+			log_cmd.push_back("-b");
+			log_cmd.push_back(buffer);
+		}
+	}
+	chmod("/dev/null", 0666);
+	clear_cmd = log_cmd;
+	log_cmd.insert(log_cmd.end(), { "-v", "threadtime", "-s", "am_proc_start", "Magisk" });
+#ifdef MAGISK_DEBUG
+	log_cmd.push_back("*:F");
+#endif
+	log_cmd.push_back(nullptr);
+
+	clear_cmd.push_back("-c");
+	clear_cmd.push_back(nullptr);
+}
+
+static void *logcat_gobbler(void *) {
+	int log_pid;
+	char line[4096];
+	while (true) {
+		// Start logcat
+		exec_t exec {
+			.fd = -1,
+			.argv = log_cmd.data()
+		};
+		log_pid = exec_command(exec);
+		FILE *logs = fdopen(exec.fd, "r");
+		while (fgets(line, sizeof(line), logs)) {
+			if (line[0] == '-')
+				continue;
+			pthread_mutex_lock(&event_lock);
+			for (auto &event : events) {
+				if (event.enable && event.filter(line))
+					event.queue.emplace_back(line);
+			}
+			pthread_mutex_unlock(&event_lock);
+		}
+
+		fclose(logs);
+		kill(log_pid, SIGTERM);
+		waitpid(log_pid, nullptr, 0);
+
+		LOGI("magisklogd: logcat output EOF");
+		// Clear buffer
+		exec_command_sync(clear_cmd.data());
+	}
+}
+
+static void *log_writer(void *) {
+	rename(LOGFILE, LOGFILE ".bak");
+	FILE *log = xfopen(LOGFILE, "ae");
+	setbuf(log, nullptr);
+	auto &queue = start_logging(LOG_EVENT);
+	while (true) {
+		fprintf(log, "%s", queue.take().c_str());
+	}
+}
+
+BlockingQueue<std::string> &start_logging(logcat_event event) {
+	pthread_mutex_lock(&event_lock);
+	events[event].enable = true;
+	pthread_mutex_unlock(&event_lock);
+	return events[event].queue;
+}
+
+void stop_logging(logcat_event event) {
+	pthread_mutex_lock(&event_lock);
+	events[event].enable = false;
+	events[event].queue.clear();
+	pthread_mutex_unlock(&event_lock);
+}
+
+bool start_logcat() {
+	if (logcat_started)
+		return true;
+	int test = exec_command_sync(MIRRDIR "/system/bin/logcat", "-d", "-f", "/dev/null");
+	chmod("/dev/null", 0666);
+	if (test != 0)
+		return false;
+	init_args();
+	pthread_t t;
+	pthread_create(&t, nullptr, log_writer, nullptr);
+	pthread_detach(t);
+	pthread_create(&t, nullptr, logcat_gobbler, nullptr);
+	pthread_detach(t);
+	logcat_started = true;
+	return true;
+}
+