lib/ directory missing after installing 64 bit Android application

Issue

My 32-bit ARM Android apps come with .so files that I dlopen() in my native code. This works just fine, and I can dlopen them at the /data/data/com.domain.app/lib/libX.so location.

If I add 64-bit binaries to my package (arm64-v8a) and install it on a 64 bit Android device, then there will be no /data/data/com.domain.app/lib directory present.

After some investigation, I found that the .so files on a 64-bit Android device end up in a different directory:

/data/app/com.domain.app-1/lib/arm64

And to make matters worse, the '-1' suffix varies, and could be '-2' or something else.

This is a way to check what got installed in the application's home directory:

$ adb shell run-as com.steenriver.biplane '/system/bin/sh -c "pwd"' /data/data/com.steenriver.biplane

$ adb shell run-as com.steenriver.biplane '/system/bin/sh -c "ls -al"' drwxrwx--x u0_a108 u0_a108 2017-01-17 15:04 app_.gpg.classloader drwxrwx--x u0_a108 u0_a108 2017-01-17 15:04 cache drwxrwx--x u0_a108 u0_a108 2017-01-17 15:04 code_cache drwxrwx--x u0_a108 u0_a108 2017-01-17 15:04 files

A 32 bit device will have a lib/ entry listed here.

Is there an Android call I can do (Either in Java or native code) that will tell me where the .so files have ended up, so I can dlopen() them?

Solution

For 64-bit ARM, there is no longer a symbolic link made to the library directory. To find the .so files, you can use the following Java code in onCreate()

import android.content.pm.PackageInfo;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
...
ApplicationInfo ainfo = this.getApplicationContext().getPackageManager().getApplicationInfo
( 
    "com.domain.app",
    PackageManager.GET_SHARED_LIBRARY_FILES
);
Log.v( TAG, "native library dir " + ainfo.nativeLibraryDir );

Compare this with 32-bit ARM, where a symlink is provided:

$ adb shell run-as com.steenriver.littlecrane '/system/bin/sh -c "pwd"'
/data/data/com.steenriver.littlecrane
$ adb shell run-as com.steenriver.littlecrane '/system/bin/sh -c "ls -al"'
drwxrwx--x u0_a109  u0_a109           2017-01-18 11:48 app_.gpg.classloader
drwxrwx--x u0_a109  u0_a109           2017-01-18 11:26 cache
drwxrwx--x u0_a109  u0_a109           2017-01-18 11:48 code_cache
drwxrwx--x u0_a109  u0_a109           2017-01-18 11:47 files
lrwxrwxrwx root     root              2017-01-18 11:48 lib -> /data/app/com.steenriver.littlecrane-2/lib/arm

Answered By - Bram