use writable overlays?

[stsp]

Hi, have the writable overlays been considered for appimages? I am trying to package the proprietary programs (a DOS programs actually) that are not educated enough to write to tmp dirs or alike. I think fuse has fuse-overlayfs, so such a feature is not going to be difficult to implement?

[probonopd]

Hi @stsp

It's doable by putting fuse-overlayfs into the AppImage, and then invoking it from the AppRun script.
See https://github.com/AppImage/AppImageKit/wiki/Bundling-Windows-applications#3-make-it-possible-to-use-a-read-only-wineprefix-1.

Such functionality goes into the AppImage payload, not into the runtime.

[stsp]

I actually thought your suggestion works... But it appears not. There is some problem, I think in fuse-overlayfs: it makes only the dir writable, but all existing files are still read-only, as strange as it may sound. I filled this ticket: containers/fuse-overlayfs#428
It has a ready-to-use AppImage test-case within.
So if you can help, please join that ticket. :)

[probonopd]

Sounds like a bug to me.

[stsp]

Have you tried my reproducer? Does it reproduce for you as well?

[probonopd]

Sorry, can't try to reproduce right now. Can you reproduce this in a simple test case that does not involve AppImage?

[stsp]

Ok, added a trivial test-case to the aforementioned ticket.

[stsp]

And found the problem: the files are not writable if in the lowerdir they belong to another user.