Method InitArtMethod

Bcore/src/main/cpp/jnihook/ArtM.cpp:119–158

}

void ArtM::InitArtMethod(JNIEnv *env, int api_level) {
    registerArtNative(env);
    ArtMethodEnv.api_level = api_level;

    jclass clazz = env->FindClass("top/niunaijun/jnihook/jni/ArtMethod");
    jmethodID nativeOffsetId = env->GetStaticMethodID(clazz, "nativeOffset", "()V");
    jmethodID nativeOffset2Id = env->GetStaticMethodID(clazz, "nativeOffset2", "()V");

    void *nativeOffset = GetArtMethod(env, clazz, nativeOffsetId);
    void *nativeOffset2 = GetArtMethod(env, clazz, nativeOffset2Id);
    ArtMethodEnv.art_method_size = (size_t) nativeOffset2 - (size_t) nativeOffset;

    // calc native offset
    auto artMethod = reinterpret_cast<uintptr_t *>(nativeOffset);
    for (int i = 0; i < ArtMethodEnv.art_method_size; ++i) {
        if (reinterpret_cast<void *>(artMethod[i]) == native_offset) {
            ArtMethodEnv.art_method_native_offset = i;
            break;
        }
    }

    uint32_t flags = 0x0;
    flags = flags | kAccPublic;
    flags = flags | kAccStatic;
    flags = flags | kAccNative;
    flags = flags | kAccFinal;
    if (api_level >= __ANDROID_API_Q__) {
        flags = flags | kAccPublicApi;
    }

    char *start = reinterpret_cast<char *>(artMethod);
    for (int i = 1; i < ArtMethodEnv.art_method_size; ++i) {
        auto value = *(uint32_t * )(start + i * sizeof(uint32_t));
        if (value == flags) {
            ArtMethodEnv.art_method_flags_offset = i * sizeof(uint32_t);
            ArtMethodEnv.art_method_dex_code_item_offset = (i + 1) * sizeof(uint32_t);
            break;
        }
    }
}