Install stub if necessary

build.py

@@ -445,8 +445,8 @@ def setup_ndk(args):
 
 def setup_avd(args):
     if not args.skip:
-        build_binary(args)
+        args.release = False
-        build_app(args)
+        build_all(args)
 
     header('* Setting up emulator')
 
@@ -463,8 +463,8 @@ def setup_avd(args):
 
 def patch_avd_ramdisk(args):
     if not args.skip:
-        build_binary(args)
+        args.release = False
-        build_app(args)
+        build_all(args)
 
     header('* Patching emulator ramdisk.img')
 

native/jni/core/bootstages.cpp

@@ -18,7 +18,6 @@
 using namespace std;
 
 static bool safe_mode = false;
-static int stub_fd = -1;
 bool zygisk_enabled = false;
 
 /*********
@@ -123,10 +122,7 @@ static bool magisk_env() {
 
     LOGI("* Initializing Magisk environment\n");
 
-    string stub_path = MAGISKTMP + "/stub.apk";
+    preserve_stub_apk();
-    stub_fd = xopen(stub_path.data(), O_RDONLY | O_CLOEXEC);
-    unlink(stub_path.data());
-
     string pkg;
     get_manager(0, &pkg);
 
@@ -375,18 +371,6 @@ void boot_complete(int client) {
     if (access(SECURE_DIR, F_OK) != 0)
         xmkdir(SECURE_DIR, 0700);
 
-    if (stub_fd > 0) {
+    // Ensure manager exists
-        if (get_manager() < 0) {
+    get_manager(0, nullptr, true);
-            // Install stub
-            struct stat st{};
-            fstat(stub_fd, &st);
-            char apk[] = "/data/stub.apk";
-            int dfd = xopen(apk, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0600);
-            xsendfile(dfd, stub_fd, nullptr, st.st_size);
-            close(dfd);
-            install_apk(apk);
-        }
-        close(stub_fd);
-        stub_fd = -1;
-    }
 }

native/jni/core/package.cpp

@@ -3,6 +3,8 @@
 #include <daemon.hpp>
 #include <db.hpp>
 
+#include "core.hpp"
+
 using namespace std;
 
 // These functions will be called on every single zygote process specialization and su request,
@@ -10,11 +12,13 @@ using namespace std;
 // or simply skipped unless necessary.
 
 static atomic<ino_t> pkg_xml_ino = 0;
+static atomic_flag skip_check;
 
-// pkg_lock protects mgr_app_id and mgr_pkg
 static pthread_mutex_t pkg_lock = PTHREAD_MUTEX_INITIALIZER;
+// pkg_lock protects all following variables
 static int mgr_app_id = -1;
 static string *mgr_pkg;
+static int stub_apk_fd = -1;
 
 bool need_pkg_refresh() {
     struct stat st{};
@@ -24,8 +28,7 @@ bool need_pkg_refresh() {
         // Packages have not changed
         return false;
     } else {
-        mutex_guard g(pkg_lock);
+        skip_check.clear();
-        mgr_app_id = -1;
         return true;
     }
 }
@@ -62,7 +65,27 @@ vector<bool> get_app_no_list() {
     return list;
 }
 
-int get_manager(int user_id, string *pkg) {
+void preserve_stub_apk() {
+    mutex_guard g(pkg_lock);
+    string stub_path = MAGISKTMP + "/stub.apk";
+    stub_apk_fd = xopen(stub_path.data(), O_RDONLY | O_CLOEXEC);
+    unlink(stub_path.data());
+}
+
+static void install_stub() {
+    if (stub_apk_fd < 0)
+        return;
+    struct stat st{};
+    fstat(stub_apk_fd, &st);
+    char apk[] = "/data/stub.apk";
+    int dfd = xopen(apk, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0600);
+    xsendfile(dfd, stub_apk_fd, nullptr, st.st_size);
+    lseek(stub_apk_fd, 0, SEEK_SET);
+    close(dfd);
+    install_apk(apk);
+}
+
+int get_manager(int user_id, string *pkg, bool install) {
     mutex_guard g(pkg_lock);
 
     char app_path[128];
@@ -70,14 +93,16 @@ int get_manager(int user_id, string *pkg) {
     if (mgr_pkg == nullptr)
         default_new(mgr_pkg);
 
-    int app_id = mgr_app_id;
+    if (skip_check.test_and_set()) {
-    if (app_id > 0) {
+        if (mgr_app_id < 0) {
+            goto not_found;
+        }
         // Just need to check whether the app is installed in the user
         const char *name = mgr_pkg->empty() ? JAVA_PACKAGE_NAME : mgr_pkg->data();
         snprintf(app_path, sizeof(app_path), "%s/%d/%s", APP_DATA_DIR, user_id, name);
         if (access(app_path, F_OK) == 0) {
             if (pkg) *pkg = name;
-            return user_id * AID_USER_OFFSET + app_id;
+            return user_id * AID_USER_OFFSET + mgr_app_id;
         } else {
             goto not_found;
         }
@@ -166,6 +191,8 @@ int get_manager(int user_id, string *pkg) {
         // No manager app is found, clear all cached value
         mgr_app_id = -1;
         mgr_pkg->clear();
+        if (install)
+            install_stub();
     }
 
 not_found:

native/jni/include/daemon.hpp

@@ -86,9 +86,10 @@ void su_daemon_handler(int client, const sock_cred *cred);
 void zygisk_handler(int client, const sock_cred *cred);
 
 // Package
+void preserve_stub_apk();
 bool need_pkg_refresh();
 std::vector<bool> get_app_no_list();
-int get_manager(int user_id = 0, std::string *pkg = nullptr);
+int get_manager(int user_id = 0, std::string *pkg = nullptr, bool install = false);
 
 // Denylist
 void initialize_denylist();

native/jni/su/su_daemon.cpp

@@ -82,7 +82,7 @@ void su_info::check_db() {
 
     // We need to check our manager
     if (access.log || access.notify)
-        mgr_uid = get_manager(to_user_id(eval_uid), &mgr_pkg);
+        mgr_uid = get_manager(to_user_id(eval_uid), &mgr_pkg, true);
 }
 
 bool uid_granted_root(int uid) {

scripts/avd_magisk.sh

@@ -139,6 +139,8 @@ ln -s ./magisk $MAGISKTMP/resetprop
 ln -s ./magisk $MAGISKTMP/magiskhide
 ln -s ./magiskpolicy $MAGISKTMP/supolicy
 
+./magiskinit -x manager $MAGISKTMP/stub.apk
+
 mkdir -p $MAGISKTMP/.magisk/mirror
 mkdir $MAGISKTMP/.magisk/block
 touch $MAGISKTMP/.magisk/config