Unable to load libpython.so from apps (was: Building Dynamic version of library)

[GRRedWings]

I'm probably doing something wrong, but in trying to use this library, I tried with no luck to link it static in my application, but I'm wondering if it's possible to build this as a shared object instead of a static library.

[yan12125]

Could you give some more details?

[GRRedWings]

I'm staying to build the file as an .so not a .a. I have other so files in my project, and was wondering if this is a configuration you have available, or know of a quick way to achieve this.

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--------------------------- Sent from my phone. Please forgive the short nature of the message, if needed I will follow up with more details.

On Thu, Mar 14, 2019, 10:01 PM Chih-Hsuan Yen ***@***.***> wrote: Could you give some more details? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#18 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AEPt12x5o5Q09ndWvRI6MjpcmLfJKvxoks5vWv8JgaJpZM4b1BUT> .

[yan12125]

Do you mean files like libssl.a or libbz2.a? I built them as static libraries to avoid conflicts with vendor-supplied libraries in /system/lib or /system/lib64. If OpenSSL, BZip2 and so on are built as shared libraries (.so), LD_LIBRARY_PATH will be necessary to load them correctly, while setting this environment variable breaks vendor-supplied programs like /system/bin/toybox. I found this issue when I was using Android 6.0. Let me try if this is still an issue on Android 8.0.

If you want to try it out yourself, just remove --disable-shared from pybuild/packages/*.py.

[GRRedWings]

Sorry, I was thinking the python file. Libpython3.8m in particular

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--------------------------- Sent from my phone. Please forgive the short nature of the message, if needed I will follow up with more details.

On Fri, Mar 15, 2019, 7:08 AM Chih-Hsuan Yen ***@***.***> wrote: Do you mean files like libssl.a or libbz2.a? I built them as static libraries to avoid conflicts with vendor-supplied libraries in /system/lib or /system/lib64. If OpenSSL, BZip2 and so on are built as shared libraries (.so), LD_LIBRARY_PATH will be necessary to load them correctly, while setting this environment variable breaks vendor-supplied programs like /system/bin/toybox. I found this issue when I was using Android 6.0. Let me try if this is still an issue on Android 8.0. If you want to try it out yourself, just remove --disable-shared from pybuild/packages/*.py. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#18 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AEPt19S-aOIczLbavHK4G3ftCvxwOUHmks5vW38ZgaJpZM4b1BUT> .

[yan12125]

Wow, good catch! I didn't notice libpython is built as a static library by default. Now fixed.

[GRRedWings]

In trying to use the so file that is produced now, I get an error at runtime from the Android app saying that libpython3.8m.1.0 could not be found. Is there something else that needs to be done, or could it be that I'm grabbing the wrong file? I see that the 1.0 file is being produced, but renaming that does not work either.

[yan12125]

Missing $LD_LIBRARY_PATH? This is what I use to run python3: https://github.com/yan12125/python3-android/blob/master/devscripts/env.sh

[GRRedWings]

I'm not sure I follow. Everything builds, would I be able to get an outputed binary without this path?

[yan12125]

I meant setting the environment variable LD_LIBRARY_PATH to the folder containing libpython3.8m.1.0 before loading it. Seems the story is different if you use System.loadLibrary() from Java, though.

The simplest fix might be checking why the static library can't be linked. Reopening for further discussions - go back to static libraries or not?

[GRRedWings]

For me I would prefer to use the static library and figure out why it's unable to link at this time. But I also understand your hesitation and desire to revert back to what you had before. But yes, we use System.loadLibrary(). Ex. from my java code System.loadLibrary("python3.8m");

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On Wed, Mar 20, 2019 at 12:34 PM Chih-Hsuan Yen ***@***.***> wrote: I meant setting the environment variable LD_LIBRARY_PATH to the folder containing libpython3.8m.1.0 before loading it. Seems the story is different if you use System.loadLibrary() from Java, though. The simplest fix might be checking why the static library can't be linked. Reopening for further discussions - go back to static libraries or not? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#18 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AEPt15t9BfBzPYVqpeBLQ1uFO8JONSgPks5vYmMDgaJpZM4b1BUT> .

[yan12125]

I'm fine with either static libraries or dynamic libraries, as long as it works. Mind to share error messages?

System.loadLibrary("python3.8m");

Have you tried loading this library with absolute full path?

[GRRedWings]

When using the old python3.5m from GRRedwings fork, I never needed to. I can try.

Here is the output of me trying to run the application with python3.8m

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.company.app, PID: 6058
java.lang.UnsatisfiedLinkError: dlopen failed: library "libpython3.8m.so.1.0" not found
at java.lang.Runtime.loadLibrary0(Runtime.java:1071)
at java.lang.Runtime.loadLibrary0(Runtime.java:1007)
at java.lang.System.loadLibrary(System.java:1667)
at com.company.app.activities.MyActivity.initLogger(WelcomeActivity.java:1170)
at com.company.app.activities.MyActivity.onComplete(WelcomeActivity.java:926)
at com.company.app.activities.BaseActivity$19.run(BaseServiceActivity.java:1923)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:209)
at android.app.ActivityThread.main(ActivityThread.java:7021)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:486)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:872)