cookie提取dex文件

有時候在java層能獲取dex文件的cookie，可是在java不能從cookie獲得dex，若是想要獲取只能經過jni在C層實現，具體實現代碼以下(nexus手機4.4系統)

static void dumpDex(JNIEnv *env, jobject object, jint gcookie) {
    int cookie = gcookie;

    DexOrJar *a = (struct DexOrJar *) cookie;

    int len = a->pDexMemory[34] << 16 | a->pDexMemory[33] << 8 | a->pDexMemory[32];

    int fd = open("/data/local/tmp/1.dex", O_RDWR | O_CREAT);
    write(fd, a->pDexMemory, len);
    close(fd);
}