From 308c9999fa6f608fc0add8c9dca85c698531af41 Mon Sep 17 00:00:00 2001
From: topjohnwu <topjohnwu@gmail.com>
Date: Sun, 28 Jan 2024 00:42:43 -0800
Subject: [PATCH] Properly detect package changes

---
 native/src/core/daemon.cpp       |  1 -
 native/src/core/include/core.hpp |  1 -
 native/src/core/package.cpp      | 24 +++++++++++++++---------
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/native/src/core/daemon.cpp b/native/src/core/daemon.cpp
index 6e739995f..a944cebd3 100644
--- a/native/src/core/daemon.cpp
+++ b/native/src/core/daemon.cpp
@@ -157,7 +157,6 @@ static void handle_request_async(int client, int code, const sock_cred &cred) {
         break;
     case +RequestCode::ZYGOTE_RESTART:
         LOGI("** zygote restarted\n");
-        pkg_xml_ino = 0;
         prune_su_access();
         reset_zygisk(false);
         close(client);
diff --git a/native/src/core/include/core.hpp b/native/src/core/include/core.hpp
index 3051c36c2..879d93825 100644
--- a/native/src/core/include/core.hpp
+++ b/native/src/core/include/core.hpp
@@ -62,7 +62,6 @@ void su_daemon_handler(int client, const sock_cred *cred);
 void zygisk_handler(int client, const sock_cred *cred);
 
 // Package
-extern std::atomic<ino_t> pkg_xml_ino;
 void preserve_stub_apk();
 void check_pkg_refresh();
 std::vector<bool> get_app_no_list();
diff --git a/native/src/core/package.cpp b/native/src/core/package.cpp
index 2db1c6f20..70ab7e2d7 100644
--- a/native/src/core/package.cpp
+++ b/native/src/core/package.cpp
@@ -13,12 +13,11 @@ using rust::Vec;
 // so performance is absolutely critical. Most operations should either have its result cached
 // or simply skipped unless necessary.
 
-atomic<ino_t> pkg_xml_ino = 0;
-static atomic_flag skip_mgr_check;
-
 static pthread_mutex_t pkg_lock = PTHREAD_MUTEX_INITIALIZER;
 // pkg_lock protects all following variables
 static int mgr_app_id = -1;
+static bool skip_mgr_check;
+static timespec *app_ts;
 static string *mgr_pkg;
 static Vec<uint8_t> *mgr_cert;
 static int stub_apk_fd = -1;
@@ -29,12 +28,17 @@ static bool operator==(const Vec<uint8_t> &a, const Vec<uint8_t> &b) {
 }
 
 void check_pkg_refresh() {
-    struct stat st{};
-    if (stat("/data/system/packages.xml", &st) == 0 &&
-        pkg_xml_ino.exchange(st.st_ino) != st.st_ino) {
-        skip_mgr_check.clear();
-        skip_pkg_rescan.clear();
+    mutex_guard g(pkg_lock);
+    if (app_ts == nullptr)
+        default_new(app_ts);
+    if (struct stat st{}; stat("/data/app", &st) == 0) {
+        if (memcmp(app_ts, &st.st_mtim, sizeof(timespec)) == 0) {
+            return;
+        }
+        memcpy(app_ts, &st.st_mtim, sizeof(timespec));
     }
+    skip_mgr_check = false;
+    skip_pkg_rescan.clear();
 }
 
 // app_id = app_no + AID_APP_START
@@ -124,7 +128,7 @@ int get_manager(int user_id, string *pkg, bool install) {
         return true;
     };
 
-    if (skip_mgr_check.test_and_set()) {
+    if (skip_mgr_check) {
         if (mgr_app_id >= 0) {
             // Just need to check whether the app is installed in the user
             const char *name = mgr_pkg->empty() ? JAVA_PACKAGE_NAME : mgr_pkg->data();
@@ -144,6 +148,8 @@ int get_manager(int user_id, string *pkg, bool install) {
         // This means that we check all users, not just the requested user.
         // Certificates are also verified to prevent manipulation.
 
+        skip_mgr_check = true;
+
         db_strings str;
         get_db_strings(str, SU_MANAGER);