Android NDK Linker wrong path

Issue

I'm currently working with a NDK Project that uses shared libraries. And I have two shared libraries to integrate: libsatprotocol.so and libsat-tanca.so.

So I added to my Android.mk these libraries so I could make a wrapper. For libsatprotocol everything is working fine. But for libsat-tanca, I get a crash on android:

 java.lang.UnsatisfiedLinkError: dlopen failed: could not load library "/home/lucas/Rockspoon/satlib/Android/app/src/main/obj/local/armeabi/libsat-tanca.so" needed by "libsat-jni.so"; caused by library "/home/lucas/Rockspoon/satlib/Android/app/src/main/obj/local/armeabi/libsat-tanca.so" not found
                                                                              at java.lang.Runtime.loadLibrary(Runtime.java:371)
                                                                              at java.lang.System.loadLibrary(System.java:989)

So the weird thing is that this path in my computer path for the library, and I have no clue from where it is getting it. If I remove the libsat-tanca of the dependencies, it works fine (in libsatprotocol).

Here are my Android.mk:

LOCAL_PATH := $(call my-dir)
#LOCAL_ALLOW_UNDEFINED_SYMBOLS=true

include $(CLEAR_VARS)

LOCAL_MODULE    := sat-tanca
LOCAL_SRC_FILES := tanca/$(TARGET_ARCH_ABI)/libsat-tanca.so

include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)

LOCAL_MODULE    := sat-dimep
LOCAL_SRC_FILES := dimep/$(TARGET_ARCH_ABI)/libsatprotocol.so

include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)

LOCAL_MODULE    := sat-jni
LOCAL_SRC_FILES := satlib.c
LOCAL_LDLIBS    += -L$(SYSROOT)/usr/lib -lz -llog
LOCAL_SHARED_LIBRARIES := sat-tanca sat-dimep

include $(BUILD_SHARED_LIBRARY)

Application.mk

APP_ABI := armeabi #armeabi-v7a mips x86 x86_64
LOCAL_SRC_FILES := $(TARGET_ARCH_ABI)/libsatprotocol.so $(TARGET_ARCH_ABI)/libsat-tanca.so

SATControl.java

static {
  System.loadLibrary("sat-jni");
}

build.gradle (app)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.3"

    defaultConfig {
        applicationId "com.rockspoon.libraries.satlib"
        minSdkVersion 19
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        ndk {
            moduleName "sat-jni"
        }
    }

    sourceSets.main {
        jni.srcDirs = [] // This prevents the auto generation of Android.mk
        jniLibs.srcDir 'src/main/libs' // This is not necessary unless you have precompiled libraries in your project.
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    task buildNative(type: Exec, description: 'Compile JNI source via NDK') {
        def ndkDir = android.ndkDirectory
        commandLine "$ndkDir/ndk-build",
                '-C', file('src/main/jni').absolutePath, // Change src/main/jni the relative path to your jni source
                '-j', Runtime.runtime.availableProcessors(),
                'all',
                'NDK_DEBUG=1'
    }

    task cleanNative(type: Exec, description: 'Clean JNI object files') {
        def ndkDir = android.ndkDirectory
        commandLine "$ndkDir/ndk-build",
                '-C', file('src/main/jni').absolutePath, // Change src/main/jni the relative path to your jni source
                'clean'
    }

    clean.dependsOn 'cleanNative'

    tasks.withType(JavaCompile) {
        compileTask -> compileTask.dependsOn buildNative
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.4.0'
}

Any idea why it is linking just the libsat-tanca.so with my PC path?

Solution

There are two things that look wrong to me here, but I don't know for sure that this is what is causing the link path to be incorrect.

1) The $(SYSROOT) variable in this line points to a path on your machine, right?

LOCAL_LDLIBS    += -L$(SYSROOT)/usr/lib -lz -llog

If linking to zlib and the log libraries is the goal, you can just use the following and the build will do the right thing:

LOCAL_LDLIBS    += -lz -llog

2) Why is the following line in your Application.mk? You shouldn't need this, but I don't think it's likely to cause the link problem.

LOCAL_SRC_FILES := $(TARGET_ARCH_ABI)/libsatprotocol.so $(TARGET_ARCH_ABI)/libsat-tanca.so

Answered By - Francesca Nannizzi