Handling dynamically loaded libraries with go-appimagetool

[VioletGiraffe]

Hi! I have an issue with deploying libcamera into AppImage. It has some dynamic modules that are loaded at runtime (not listed by ldd). Libcamera looks for them in /usr/local/lib/aarch64-linux-gnu/libcamera/. I have created a folder AppDir/usr/local/lib/aarch64-linux-gnu/libcamera/ and copied the necessary stuff there before running appimagetool, but it's not enough. If, however, I create this system folder /usr/local/lib/aarch64-linux-gnu/libcamera/ and copy the extra libraries there on the clean target system, then the AppImage works. Is there a way to fix this, patch absolute search paths inside binaries or something? On Windows you could hook the CreateFile function and replace its arguments, but I don't know if there's a similar facility on Linux.

P. S. I mentioned the Go appimagetool specifically because I need to get it working on ARM64.

[probonopd]

What happens if you export LD_LIBRARY_PATH and the run appimagetool?

export LD_LIBRARY_PATH=/usr/local/lib/aarch64-linux-gnu/libcamera/
appimagetool [-s] deploy (...)

[VioletGiraffe]

Thanks a lot for responding! Your suggestion seems to have made no difference, the AppDir does not have .so files from /usr/local/lib/aarch64-linux-gnu/libcamera/ in my AppDir/usr/local/lib/aarch64-linux-gnu/libcamera/. And, of course, when this AppImage runs on the clean system, libcamera complains that it can't find its modules.

[probonopd]

Which application are you trying to make an AppImage of?

[probonopd]

It looks like you encoded the absolute paths. I wasn't aware that this was even allowed.

Try encoding the filenames onl without their path. Start with a clean binary (on which patchelf never ran before), and try:

for file in /usr/local/lib/aarch64-linux-gnu/libcamera/*.so; do
   if [ -e "$file" ]; then
       patchelf --add-needed $(dirname "$file") ./AppDir/usr/bin/"$app_name"
   fi
done

[VioletGiraffe]

Thank you, that works in conjunction with export LD_LIBRARY_PATH=/usr/local/lib/aarch64-linux-gnu/libcamera/, in the sense that AppImage is produced and contains these libraries. But when I try running in on a clean system, I still get:

WARN IPAManager ipa_manager.cpp:154 No IPA found in '/usr/local/lib/aarch64-linux-gnu/libcamera'

[probonopd]

You need to check the code that produces the No IPA found message. Which files is it trying to load from which exact paths, and do those files exist at these paths in the AppDir? (Must not be absolute paths inside /usr/local/... because those won't exist on your users' machines)

[VioletGiraffe]

I think I've found the relevant code and a way to specify a different path via an environment variable. But what about a universal solution? AppRun knows /usr/local/lib/... paths should be redirected, is there no way to handle this?

[probonopd]

AppRun does not "redirect" any paths. You need to change the code so that the paths to the files you want to load are calculated relative to the main binary, instead of hardcoding absolute paths.

More information:
https://docs.appimage.org/reference/best-practices.html?highlight=relocatable#binaries-must-not-use-compiled-in-absolute-paths

[VioletGiraffe]

Hi @probonopd, a quick question, if I may, which seems close enough to the original topic. How do I correctly deploy more than one executable with go-appimagetool? Not .so, but a top-level executable that will be called at runtime by the main executable. I can cp it to the AppDir, but how to tell appimagetool to deploy its dependencies?

[probonopd]

Not sure if I had implemented this yet. Usually every application should get its own AppImage. The main exception being auxiliary applications that are invoked by the main application. Possibly this still would need to be implemented, don't quite remember.