[sane-devel] Issue 642

Andy Bennett andyjpb at ashurst.eu.org
Sun Jun 18 13:14:42 BST 2023


> since I badly need scanimage as a commandline tool and there seems to be no 
> progress on the issue
> https://gitlab.com/sane-project/backends/-/issues/642
> I would like to try myself to work on a fix. However, I would need some 
> guidance about where to look in the code.
> Could someone give me a hand? Also, every piece information is very welcome!
> I don't know, what endeavour I am embarking on and what my 
> chances will be... 
> What do you think about my chances?

I've just read the issue for the first time and haven't been involved but I 
noticed that you mentioned "Works with all formats (jpeg, tiff, png, pnm) 
and with a resolution of 600. scanimage does not crash, the images are not 
corrupt." and then provide examples where it does crash.

However, you don't say if you can make it crash with a pnm format output.

If you haven't done so, it might be worth trying to make it crash with a 
pnm output.

1) If it never does then it would suggest (to me) that the bug is between 
the scanning code and the format conversion code: perhaps the backend 
provides information that causes the format conversion code to be 
initialised incorrectly for the page size, which causes trouble when data 
aligns (or doesn't align) in certain ways.

2) However, if a pnm is produced but is truncated then you know the problem 
is with the amount of data that the backend is collecting.

3) If it still crashes in the same way then that could eliminate the file 
conversion code and point to a (perhaps) more serious bug in the backend.

Anyway, perhaps this is useful?

Good luck with the debugging.

Best wishes,

andyjpb at ashurst.eu.org

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