LibMainLoader

Acts as a proxy libmain.so for Unity code injection via il2cpp on Android.

Specifically stubs out: JNI_OnLoad, JNI_OnUnload

Building

1. Make ndkpath.txt point to your NDK install of at least r25.
2. Run build.ps1, which will configure CMake for you, and make a build directory, then will execute ninja -C build on that directory.

To adjust any build flags, edit CMakeLists.txt directly, or forward the args through the command line.

To build with decreased codesize (although not substantially), define NO_EXCESS_LOGGING.

Usage

After building, which targets AArch64, replace the existing libmain.so in your unity application with the built libmain.so.

Then, place a modloader at: /sdcard/ModData/<application id>/Modloader/*.so.

This binary will walk the

Modloader

Ultimately a modloader must be dlopen-able without any specific dependencies. It should also be okay with being dlopened into the GLOBAL symbol lookup table. After that, it may optionally define the following (extern C) functions, which will be called at various points during the loading process:

Signature	Call point
void modloader_preload(JNIEnv* env, char const* appId, char const* modloaderPath, char const* modloaderSourcePath, char const* filesDir, char const* externalDir) noexcept	Called immediately after dlopen of the modloader. Forwards parameters that may be useful (largely to avoid duplicate JNI calls).
void modloader_load(JNIEnv* env, char const* soDir) noexcept	Called after the JavaVM is found as part of the main loading process, via JNI_OnLoad.
void modloader_accept_unity_handle(JNIEnv* env, void* unityHandle) noexcept	Called after libunity.so is dlopened, but before Unity's JNI_OnLoad is called.
void modloader_unload(JavaVM* vm) noexcept	Called when JNI_OnUnload is called, after the JavaVM is obtained during teardown.

Resources

Updated libmain part from https://github.com/sc2ad/QuestLoader