improve: preload modules globally

This commit makes Zygisk modules be preloaded globally in the main Zygote process, so that they don't need to reload all the time. This commit is authored by @nampud, and merged into mainline ReZygisk.

Co-authored-by: nampud

loader/src/injector/hook.cpp

@@ -66,7 +66,6 @@ struct ZygiskContext {
     } args;
 
     const char *process;
-    list<ZygiskModule> modules;
 
     int pid;
     bitset<FLAG_MAX> flags;
@@ -124,6 +123,10 @@ struct ZygiskContext {
 // Global variables
 vector<tuple<dev_t, ino_t, const char *, void **>> *plt_hook_list;
 map<string, vector<JNINativeMethod>> *jni_hook_list;
+
+bool modules_loaded = false;
+list<ZygiskModule> modules;
+
 bool should_unmap_zygisk = false;
 bool enable_unloader = false;
 bool hooked_unloader = false;
@@ -824,15 +827,6 @@ void ZygiskContext::app_specialize_pre() {
         setenv("ZYGISK_ENABLED", "1", 1);
     }
 
-    /* INFO: Because we load directly from the file, we need to do it before we umount
-                the mounts, or else it won't have access to /data/adb anymore.
-    */
-    if (!load_modules_only()) {
-        LOGE("Failed to load modules");
-
-        return;
-    }
-
     /* INFO: Modules only have two "start off" points from Zygisk, preSpecialize and
                 postSpecialize. In preSpecialize, the process still has privileged 
                 permissions, and therefore can execute mount/umount/setns functions.
@@ -908,11 +902,15 @@ void ZygiskContext::nativeForkSystemServer_pre() {
     LOGV("pre forkSystemServer");
     flags[SERVER_FORK_AND_SPECIALIZE] = true;
 
+    if (!modules_loaded) {
+        load_modules_only();
+        modules_loaded = true;
+    }
+
     fork_pre();
     if (!is_child())
       return;
 
-    load_modules_only();
     run_modules_pre();
     rezygiskd_system_server_started();