How to cross compile OpenSSL for 64 bit Android on OSX Darwin using NDK 19

I was able to build, link, and run openssl for android arm64 with NDK r19. But I had to use the standalone toolchain generated from android-ndk-r19.

$ cd /path/to/android-ndk-r19 $ ./build/tools/make-standalone-toolchain.sh \ --toolchain=aarch64-linux-android 

this will generate a dir called aarch64-linux-android in your tmp dir, put its bin directory in your path. Also, set your ANDROID_NDK_HOME to this location.

$ export PATH=/path/to/aarch64-linux-android/bin:${PATH} $ export ANDROID_NDK_HOME=/path/to/aarch64-linux-android 

then just run openssl's Configure and make.

$ cd /path/to/openssl1.1.1 $ ./Configure android-arm64 $ make 

./Configure's output was as follows:

$ ./Configure android-arm64 Configuring OpenSSL version 1.1.1b-dev (0x10101020L) for android-arm64 Using os-specific seed configuration Creating configdata.pm Creating Makefile ********************************************************************** *** *** *** OpenSSL has been successfully configured *** *** *** *** If you encounter a problem while building, please open an *** *** issue on GitHub <https://github.com/openssl/openssl/issues> *** *** and include the output from the following command: *** *** *** *** perl configdata.pm --dump *** *** *** *** (If you are new to OpenSSL, you might want to consult the *** *** 'Troubleshooting' section in the INSTALL file first) *** *** *** ********************************************************************** $ 

and finally I created a new Android Studio project, with c++11, exceptions, and rtti support (through the new project wizard), and linked in the output of the build with a CMakeLists.txt slightly modified from the one created by Android Studio:

cmake_minimum_required(VERSION 3.4.1) # Creates and names a library, sets it as either STATIC # or SHARED, and provides the relative paths to its source code. # You can define multiple libraries, and CMake builds them for you. # Gradle automatically packages shared libraries with your APK. add_library( # Sets the name of the library. native-lib # Sets the library as a shared library. SHARED # Provides a relative path to your source file(s). src/main/cpp/native-lib.cpp ) # Searches for a specified prebuilt library and stores the path as a # variable. Because CMake includes system libraries in the search path by # default, you only need to specify the name of the public NDK library # you want to add. CMake verifies that the library exists before # completing its build. find_library( # Sets the name of the path variable. log-lib # Specifies the name of the NDK library that # you want CMake to locate. log ) # HERE ARE THE PARTS I EDITED: # NOTE FOR THE COMMANDS ABOVE, THIS IS JUST THE OPENSSL SOURCE DIR. set (SSL_PATH /path/to/ssl/build/outputs/) include_directories(${SSL_PATH}/include) set (open-ssl-libs ${SSL_PATH}/libssl.a ${SSL_PATH}/libcrypto.a) # Specifies libraries CMake should link to your target library. You # can link multiple libraries, such as libraries you define in this # build script, prebuilt third-party libraries, or system libraries. target_link_libraries( # Specifies the target library. native-lib # LINK SSL AND CRYPTO HERE: ${open-ssl-libs} # Links the target library to the log library # included in the NDK. ${log-lib} ) 

this is enough to show that it links, but I added one small reference to libssl.a in the boilerplate c++ code generated by Android Studio:

#include <jni.h> #include <string> #include <openssl/ssl.h> extern "C" JNIEXPORT jstring JNICALL Java_com_vernier_android_test_1ssl_MainActivity_stringFromJNI( JNIEnv* env, jobject /* this */) { SSL* ssl = SSL_new(nullptr); std::string hello = "Hello from C++"; return env->NewStringUTF(hello.c_str()); } 

and I ran the app successfully.