[sane-devel] Permission denied on parallel port Epson Expression636

khk@khk.net khk@khk.net
Thu, 3 Oct 2002 14:29:04 -0400 (EDT)


This is a limitation all parallel port scanners have when used with Sane.
You already know the reason for this: Sane uses the IO ports and not
the device file to talk to the scanner.

As long as you trust everybody who's using your computer, you can just
make the frontend(s) you are using setuid root programs. This way, the
program will always run as root, regardless of which user is actually
running it.

Karl Heinz

> Hello,
>
> I got my hands on the Epson Expression636 which comes with both SCSI and
> parallel ports. W/o SCSI on my RedHat8 box, I tried the parallel
> port. Scanning works if I'm root (Yes!!) but not as a regular user. This
> my diagnostics:
[ ... ]
>
> Seeing that /dev/lp0 has rw access by root.lp, I added myself to the lp
> group to no effect. I suspect the Epson backend is using some direct
> write to the binary address bypassing /dev/lp0.
>
> Searching the archive and Google yielded nothing.
>
> Thanks for your help.
>
> Best,
> Petr
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