LSPlant/library/jni/art/runtime/class_linker.hpp

#pragma once

#include "art/runtime/art_method.hpp"
#include "art/mirror/class.hpp"
#include "art/thread.hpp"
#include "common.hpp"

namespace lsplant::art {

class ClassLinker {

private:
    CREATE_MEM_FUNC_SYMBOL_ENTRY(
            void, SetEntryPointsToInterpreter, ClassLinker *thiz, ArtMethod *art_method) {
        if (SetEntryPointsToInterpreterSym) [[likely]] {
            SetEntryPointsToInterpreterSym(thiz, art_method);
        }
    }

    [[gnu::always_inline]]
    static void MaybeDelayHook(mirror::Class *clazz) {
        const auto *class_def = clazz->GetClassDef();
        bool should_intercept = class_def && IsPending(class_def);
        if (should_intercept) [[unlikely]] {
            LOGD("Pending hook for %p (%s)", clazz, clazz->GetDescriptor().c_str());
            OnPending(class_def);
        }
    }

    CREATE_MEM_HOOK_STUB_ENTRY(
            "_ZN3art11ClassLinker22FixupStaticTrampolinesENS_6ObjPtrINS_6mirror5ClassEEE",
            void, FixupStaticTrampolines, (ClassLinker * thiz, mirror::Class * clazz), {
                backup(thiz, clazz);
                MaybeDelayHook(clazz);
            });

    CREATE_MEM_HOOK_STUB_ENTRY(
            "_ZN3art11ClassLinker22FixupStaticTrampolinesEPNS_6ThreadENS_6ObjPtrINS_6mirror5ClassEEE",
            void, FixupStaticTrampolinesWithThread,
            (ClassLinker * thiz, Thread * self, mirror::Class * clazz), {
                backup(thiz, self, clazz);
                MaybeDelayHook(clazz);
            });

    CREATE_MEM_HOOK_STUB_ENTRY(
            "_ZN3art11ClassLinker20MarkClassInitializedEPNS_6ThreadENS_6HandleINS_6mirror5ClassEEE",
            void*, MarkClassInitialized, (ClassLinker * thiz, Thread * self, uint32_t * clazz_ptr),
            {
                void *result = backup(thiz, self, clazz_ptr);
                auto clazz = reinterpret_cast<mirror::Class *>(*clazz_ptr);
                MaybeDelayHook(clazz);
                return result;
            });

    CREATE_HOOK_STUB_ENTRY(
            "_ZN3art11ClassLinker30ShouldUseInterpreterEntrypointEPNS_9ArtMethodEPKv",
            bool, ShouldUseInterpreterEntrypoint, (ArtMethod * art_method, const void *quick_code),
            {
                if (quick_code != nullptr &&
                    (IsHooked(art_method) || IsPending(art_method))) [[unlikely]] {
                    return false;
                }
                return backup(art_method, quick_code);
            });

    CREATE_FUNC_SYMBOL_ENTRY(void, art_quick_to_interpreter_bridge, void*) {}

    CREATE_FUNC_SYMBOL_ENTRY(void, art_quick_generic_jni_trampoline, void*) {}

    CREATE_HOOK_STUB_ENTRY(
            "_ZN3art11interpreter29ShouldStayInSwitchInterpreterEPNS_9ArtMethodE",
            bool, ShouldStayInSwitchInterpreter, (ArtMethod * art_method), {
                if (IsHooked(art_method) || IsPending(art_method)) [[unlikely]] {
                    return false;
                }
                return backup(art_method);
            });

public:
    static bool Init(const HookHandler &handler) {
        int api_level = GetAndroidApiLevel();

        if (!RETRIEVE_MEM_FUNC_SYMBOL(SetEntryPointsToInterpreter,
                                      "_ZNK3art11ClassLinker27SetEntryPointsToInterpreterEPNS_9ArtMethodE")) {
            return false;
        }

        if (!HookSyms(handler, ShouldUseInterpreterEntrypoint, ShouldStayInSwitchInterpreter)) {
            return false;
        }

        if (api_level >= __ANDROID_API_R__) {
            // In android R, FixupStaticTrampolines won't be called unless it's marking it as
            // visiblyInitialized.
            // So we miss some calls between initialized and visiblyInitialized.
            // Therefore we hook the new introduced MarkClassInitialized instead
            // This only happens on non-x86 devices
            if (!HookSyms(handler, MarkClassInitialized) ||
                !HookSyms(handler, FixupStaticTrampolinesWithThread, FixupStaticTrampolines)) {
                return false;
            }
        } else {
            if (!HookSyms(handler, FixupStaticTrampolines)) {
                return false;
            }
        }

        // MakeInitializedClassesVisiblyInitialized will cause deadlock
        // IsQuickToInterpreterBridge is inlined
        // So we use GetSavedEntryPointOfPreCompiledMethod instead

        if (!RETRIEVE_FUNC_SYMBOL(art_quick_to_interpreter_bridge,
                                  "art_quick_to_interpreter_bridge")) {
            return false;
        }
        if (!RETRIEVE_FUNC_SYMBOL(art_quick_generic_jni_trampoline,
                                  "art_quick_generic_jni_trampoline")) {
            return false;
        }

        LOGD("art_quick_to_interpreter_bridge = %p", art_quick_to_interpreter_bridgeSym);
        LOGD("art_quick_generic_jni_trampoline = %p", art_quick_generic_jni_trampolineSym);
        return true;
    }

    [[gnu::always_inline]]
    static bool SetEntryPointsToInterpreter(ArtMethod *art_method) {
        if (art_quick_to_interpreter_bridgeSym && art_quick_generic_jni_trampolineSym) [[likely]] {
            if (art_method->GetAccessFlags() & ArtMethod::kAccNative) [[unlikely]] {
                art_method->SetEntryPoint(
                        reinterpret_cast<void *>(art_quick_generic_jni_trampolineSym));
            } else {
                art_method->SetEntryPoint(
                        reinterpret_cast<void *>(art_quick_to_interpreter_bridgeSym));
            }
            return true;
        }
        if (SetEntryPointsToInterpreterSym) [[likely]] {
            SetEntryPointsToInterpreter(nullptr, art_method);
            return true;
        }
        return false;
    }

};
}