安卓逆向_15（三） --- Android NDK 开发【 jni 静态注册、JNI_OnLoad 动态注册】

深碍√TFBOYSˉ_ 2023-03-14 08:22 29阅读 0赞

Android Studio开发JNI示例：[https://blog.csdn.net/wzhseu/article/details/79683045][https_blog.csdn.net_wzhseu_article_details_79683045]

JNI\_动态注册\_静态注册.zip : [https://pan.baidu.com/s/1wpTYA9euSdPqE1Z2bA\_BHA][https_pan.baidu.com_s_1wpTYA9euSdPqE1Z2bA_BHA] 提取码: 7h97

错误:  编码GBK的不可映射字符 ( [https://blog.csdn.net/talenter111/article/details/53418999][https_blog.csdn.net_talenter111_article_details_53418999] )  
解决方法： 应该使用-encoding参数指明编码方式，如：  
javah -jni **-encoding UTF-8** com.example.XXXX.XXXX.MainActivity

# 静态注册、动态注册 示例代码 #

静态注册、动态注册

/**************静态方法**********************/
    extern "C" JNIEXPORT jstring JNICALL
    Java_com_example_calc_MainActivity_stringFromJNI(
            JNIEnv* env,
            jobject /* this */) {
        std::string hello = "Hello from C++";
        return env->NewStringUTF(hello.c_str());
    }
    /*************************************************************/
    
    JNIEXPORT void JNICALL Java_com_example_jni_1demo_MainActivity_javaToC(JNIEnv *env, jobject obj)
    {
        // 获取 类
        jclass fdClass = env->FindClass("com/example/jni_demo/MainActivity");
    
        // 获取 普通方法id
        jmethodID _jmethodID = env->GetMethodID(fdClass, "_method", "()V");
    
        // 获取 静态方法id
        jmethodID _staticjmethodID = env->GetStaticMethodID(fdClass, "_staticMethod", "()V");
    
        // 调用 java中 的 普通方法
        env->CallVoidMethod(obj, _jmethodID);
    
        // 调用 java中 的 静态方法
        env->CallStaticVoidMethod(fdClass, _staticjmethodID);
    }
    
    
    /************************* 动态注册 nativate 方法 ********************************/ 
    JNINativeMethod nativeMethod[] = {  // 方法数组映射
            // 定义数组，用于绑定 java方法 和 C方法的 关系
            {"addMethod", "(FF)F", (void*)my_add},          // java中方法名，方法签名，C++中方法名
            {"subMethod", "(FF)F", (void*)my_sub},
            {"mulMethod", "(FF)F", (void*)my_mul},
            {"divMethod", "(FF)F", (void*)my_div}
    };
    
    
    /************************* 实现 JNI_OnLoad 动态注册方法 *******************************/
    JNIEXPORT jint JNI_OnLoad(JavaVM* vm, void* reserved)
    {
        JNIEnv* env;
        if(vm->GetEnv((void**)&env, JNI_VERSION_1_6) != JNI_OK)
        {
            return JNI_ERR;
        }
    
        // 获取 java native 方法对应的 类
        jclass fdClass = env->FindClass("com/example/calc/MainActivity");
    
        // 注册 java 层 native 方法
        jint retVal = env->RegisterNatives(fdClass, nativeMethod, sizeof(nativeMethod)/sizeof(nativeMethod[0]));
        if(retVal != JNI_OK)
        {
            // 注册失败返回 -1
            return JNI_ERR;
        }
        return JNI_VERSION_1_6; //必须返回一个版本号
    }

图示：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZyZWVraW5nMTAx_size_16_color_FFFFFF_t_70][]

# Android NDK 开发之 jni 静态注册 #

Android NDK 开发之 jni 静态注册 1：[https://www.bilibili.com/video/BV1UE411A7rW?p=42][https_www.bilibili.com_video_BV1UE411A7rW_p_42]

*  Java 层 调用 C/C++ 层 示例

Android NDK 开发之 jni 静态注册 2：[https://www.bilibili.com/video/BV1UE411A7rW?p=43][https_www.bilibili.com_video_BV1UE411A7rW_p_43]

*  Java 层调用 C/C++ 层，然后从 C/C++ 层调用 Java 层的 普通 字段
 *  Java 层调用 C/C++ 层，然后从 C/C++ 层调用 Java 层的 静态 字段
 *  Java 层调用 C/C++ 层，然后从 C/C++ 层调用 Java 层的 普通 方法
 *  Java 层调用 C/C++ 层，然后从 C/C++ 层调用 Java 层的 静态 方法

# Android NDK 开发之 动态注册 JNI\_OnLoad #

Android NDK 开发之 动态注册：[https://www.bilibili.com/video/BV1UE411A7rW?p=44][https_www.bilibili.com_video_BV1UE411A7rW_p_44]

*  动态注册

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZyZWVraW5nMTAx_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZyZWVraW5nMTAx_size_16_color_FFFFFF_t_70 2][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZyZWVraW5nMTAx_size_16_color_FFFFFF_t_70 3][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZyZWVraW5nMTAx_size_16_color_FFFFFF_t_70 4][]

![20200925011619601.png][]

JNI 动态注册和静态注册的详解：[https://blog.csdn.net/bill\_xiao/article/details/89095020][https_blog.csdn.net_bill_xiao_article_details_89095020]

Android：JNI 动态注册和静态注册的详解（附android studio实例）：[https://blog.csdn.net/qq\_37858386/article/details/103765111][https_blog.csdn.net_qq_37858386_article_details_103765111]

Android Studio3.0开发JNI流程------JNI静态注册和动态注册(多个类的native动态注册-经典篇)：[https://blog.csdn.net/cloverjf/article/details/78878814][https_blog.csdn.net_cloverjf_article_details_78878814]

Android JNI 函数注册的两种方式(静态注册/动态注册)：[https://www.jianshu.com/p/1d6ec5068d05][https_www.jianshu.com_p_1d6ec5068d05]

# NDK 开发总结 #

Android NDK 开发总结：[bilibili.com/video/BV1UE411A7rW?p=45][bilibili.com_video_BV1UE411A7rW_p_45]

*  静态注册、动态注册、使用 IDA 反编译简单 so 文件

回顾：[https://www.bilibili.com/video/BV1UE411A7rW?p=46][https_www.bilibili.com_video_BV1UE411A7rW_p_46]

*  jni.h 文件介绍说明

安装完jdk后就可以在安装目录的 include 目录中找到 jni.h 头文件（示例：C:\\Program Files (x86)\\Java\\jdk1.8.0\_261\\include）

jni.h 头文件，其实就是 API 文档，里面有一些方法声明、结构体、等图示：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZyZWVraW5nMTAx_size_16_color_FFFFFF_t_70 5][]

*  静态注册

![20200925150524251.png][]

如果是普通函数，第二个参数是 jobject

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZyZWVraW5nMTAx_size_16_color_FFFFFF_t_70 6][]

如果是静态函数，第二个参数是 jclass

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZyZWVraW5nMTAx_size_16_color_FFFFFF_t_70 7][]

*  动态注册

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZyZWVraW5nMTAx_size_16_color_FFFFFF_t_70 8][]

[https_blog.csdn.net_wzhseu_article_details_79683045]: https://blog.csdn.net/wzhseu/article/details/79683045
[https_pan.baidu.com_s_1wpTYA9euSdPqE1Z2bA_BHA]: https://pan.baidu.com/s/1wpTYA9euSdPqE1Z2bA_BHA
[https_blog.csdn.net_talenter111_article_details_53418999]: https://blog.csdn.net/talenter111/article/details/53418999
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZyZWVraW5nMTAx_size_16_color_FFFFFF_t_70]: /images/20230312/2f020ec6c50e4e36adbbc6e4ae600353.png
[https_www.bilibili.com_video_BV1UE411A7rW_p_42]: https://www.bilibili.com/video/BV1UE411A7rW?p=42
[https_www.bilibili.com_video_BV1UE411A7rW_p_43]: https://www.bilibili.com/video/BV1UE411A7rW?p=43
[https_www.bilibili.com_video_BV1UE411A7rW_p_44]: https://www.bilibili.com/video/BV1UE411A7rW?p=44
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[20200925011619601.png]: /images/20230312/8fdf191ae6c24d31b617d9c116a6bb12.png
[https_blog.csdn.net_bill_xiao_article_details_89095020]: https://blog.csdn.net/bill_xiao/article/details/89095020
[https_blog.csdn.net_qq_37858386_article_details_103765111]: https://blog.csdn.net/qq_37858386/article/details/103765111
[https_blog.csdn.net_cloverjf_article_details_78878814]: https://blog.csdn.net/cloverjf/article/details/78878814
[https_www.jianshu.com_p_1d6ec5068d05]: https://www.jianshu.com/p/1d6ec5068d05
[bilibili.com_video_BV1UE411A7rW_p_45]: http://bilibili.com/video/BV1UE411A7rW?p=45
[https_www.bilibili.com_video_BV1UE411A7rW_p_46]: https://www.bilibili.com/video/BV1UE411A7rW?p=46
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[20200925150524251.png]: /images/20230312/704c17f254104873a3054c258a88bae9.png
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