From 501d3e6c32c3ce9f78b6c741ce420d4388348fdd Mon Sep 17 00:00:00 2001
From: topjohnwu <topjohnwu@gmail.com>
Date: Mon, 18 May 2020 05:18:49 -0700
Subject: [PATCH] Maintain global daemon status

---
 native/jni/core/daemon.cpp    | 127 +++++++++++++++++++---------------
 native/jni/include/daemon.hpp |  11 ++-
 2 files changed, 83 insertions(+), 55 deletions(-)

diff --git a/native/jni/core/daemon.cpp b/native/jni/core/daemon.cpp
index 7818bf76a..b6eb48c06 100644
--- a/native/jni/core/daemon.cpp
+++ b/native/jni/core/daemon.cpp
@@ -20,66 +20,25 @@ using namespace std;
 int SDK_INT = -1;
 bool RECOVERY_MODE = false;
 string MAGISKTMP;
+int daemon_state = STATE_UNKNOWN;
+
 static struct stat self_st;
 
-static void verify_client(int client, pid_t pid) {
+static bool verify_client(int client, pid_t pid) {
 	// Verify caller is the same as server
 	char path[32];
 	sprintf(path, "/proc/%d/exe", pid);
 	struct stat st;
-	if (stat(path, &st) || st.st_dev != self_st.st_dev || st.st_ino != self_st.st_ino) {
-		close(client);
-		pthread_exit(nullptr);
-	}
+	return !(stat(path, &st) || st.st_dev != self_st.st_dev || st.st_ino != self_st.st_ino);
 }
 
-static void *request_handler(void *args) {
-	int client = reinterpret_cast<intptr_t>(args);
-
-	struct ucred credential;
-	get_client_cred(client, &credential);
-	if (credential.uid != 0)
-		verify_client(client, credential.pid);
-
-	int req = read_int(client);
-	switch (req) {
-	case MAGISKHIDE:
-	case POST_FS_DATA:
-	case LATE_START:
-	case BOOT_COMPLETE:
-	case SQLITE_CMD:
-	case GET_PATH:
-		if (credential.uid != 0) {
-			write_int(client, ROOT_REQUIRED);
-			close(client);
-			return nullptr;
-		}
-		break;
-	case REMOVE_MODULES:
-		if (credential.uid != UID_SHELL && credential.uid != UID_ROOT) {
-			write_int(client, 1);
-			close(client);
-			return nullptr;
-		}
-		break;
-	default:
-		break;
-	}
-
-	switch (req) {
+static void request_handler(int client, int req_code, ucred cred) {
+	switch (req_code) {
 	case MAGISKHIDE:
 		magiskhide_handler(client);
 		break;
 	case SUPERUSER:
-		su_daemon_handler(client, &credential);
-		break;
-	case CHECK_VERSION:
-		write_string(client, MAGISK_VERSION ":MAGISK");
-		close(client);
-		break;
-	case CHECK_VERSION_CODE:
-		write_int(client, MAGISK_VER_CODE);
-		close(client);
+		su_daemon_handler(client, &cred);
 		break;
 	case POST_FS_DATA:
 		post_fs_data(client);
@@ -99,15 +58,75 @@ static void *request_handler(void *args) {
 		close(client);
 		reboot();
 		break;
-	case GET_PATH:
-		write_string(client, MAGISKTMP.data());
-		close(client);
-		break;
 	default:
 		close(client);
 		break;
 	}
-	return nullptr;
+}
+
+static void handle_request(int client) {
+	int req_code;
+
+	// Verify client credentials
+	ucred cred;
+	get_client_cred(client, &cred);
+	if (cred.uid != 0 && !verify_client(client, cred.pid))
+		goto shortcut;
+
+	// Check client permissions
+	req_code = read_int(client);
+	switch (req_code) {
+	case MAGISKHIDE:
+	case POST_FS_DATA:
+	case LATE_START:
+	case BOOT_COMPLETE:
+	case SQLITE_CMD:
+	case GET_PATH:
+		if (cred.uid != 0) {
+			write_int(client, ROOT_REQUIRED);
+			goto shortcut;
+		}
+		break;
+	case REMOVE_MODULES:
+		if (cred.uid != UID_SHELL && cred.uid != UID_ROOT) {
+			write_int(client, 1);
+			goto shortcut;
+		}
+		break;
+	}
+
+	switch (req_code) {
+	// In case of init trigger launches, set the corresponding states
+	case POST_FS_DATA:
+		daemon_state = STATE_POST_FS_DATA;
+		break;
+	case LATE_START:
+		daemon_state = STATE_LATE_START;
+		break;
+	case BOOT_COMPLETE:
+		daemon_state = STATE_BOOT_COMPLETE;
+		break;
+
+	// Simple requests to query daemon info
+	case CHECK_VERSION:
+		write_string(client, MAGISK_VERSION ":MAGISK");
+		goto shortcut;
+	case CHECK_VERSION_CODE:
+		write_int(client, MAGISK_VER_CODE);
+		goto shortcut;
+	case GET_PATH:
+		write_string(client, MAGISKTMP.data());
+		goto shortcut;
+	case DO_NOTHING:
+		goto shortcut;
+	}
+
+	// Create new thread to handle complex requests
+	new_daemon_thread(std::bind(&request_handler, client, req_code, cred));
+	return;
+
+shortcut:
+	close(client);
 }
 
 static void android_logging() {
@@ -207,7 +226,7 @@ static void daemon_entry(int ppid) {
 	// Loop forever to listen for requests
 	for (;;) {
 		int client = xaccept4(fd, nullptr, nullptr, SOCK_CLOEXEC);
-		new_daemon_thread(request_handler, reinterpret_cast<void*>(client));
+		handle_request(client);
 	}
 }
 
diff --git a/native/jni/include/daemon.hpp b/native/jni/include/daemon.hpp
index f187cc376..6c29f8629 100644
--- a/native/jni/include/daemon.hpp
+++ b/native/jni/include/daemon.hpp
@@ -6,7 +6,7 @@
 
 #include <socket.hpp>
 
-// Commands require connecting to daemon
+// Daemon command codes
 enum {
 	DO_NOTHING = 0,
 	SUPERUSER,
@@ -29,8 +29,17 @@ enum {
 	DAEMON_LAST
 };
 
+// Daemon state
+enum {
+	STATE_POST_FS_DATA,
+	STATE_LATE_START,
+	STATE_BOOT_COMPLETE,
+	STATE_UNKNOWN
+};
+
 extern int SDK_INT;
 extern bool RECOVERY_MODE;
+extern int daemon_state;
 extern bool pfs_done;
 extern std::vector<std::string> module_list;
 #define APP_DATA_DIR (SDK_INT >= 24 ? "/data/user_de" : "/data/user")