[sane-devel] Setting up Canon Perfection USB scanner for use in network: questions, problems

[Nigel Ridley]

Niki Kovacs wrote:
> Hi,
> 
> I have a small home LAN consisting of four PC's: one old Pentium III box
> acting as gateway / connection handler / printer server / file server /
> scanner server, and then one desktop and two laptops. I recently
> migrated this LAN from Slackware 10.2 to CentOS 4.3, and everything runs
> rather fine. 
> 
> One thing I have some trouble setting up is my Canon Perfection USB
> scanner for network use, which worked fine with Slackware, because
> things work a bit differently under CentOS.
> 
> The scanner is attached to the "server" box (192.168.1.1) with a minimal
> install of CentOS, no window manager, no X. I installed sane-backends on
> this machine and ran scanimage -L as root, which gave this:
> 
> [root at babasse ~]# scanimage -L
> device `epson:libusb:001:002' is a Epson Perfection610 flatbed scanner
> 
> I read the various docs on sane-project.org, especially this document:
> 
> http://penguin-breeder.org/sane/saned/
> 
> My first problem, and apparently one big difference between CentOS and
> Slackware, is that there is no entry for the scanner in /dev. Now what
> does the above output of scanimage -L exactly mean? That my scanner
> device file is /proc/bus/usb/001/002?
> 
> [root at babasse 001]# ls -l /proc/bus/usb/001/002
> -rw-r--r--  1 root root 50 jun  5 08:57 /proc/bus/usb/001/002
> 
> Now, if that is the case (if not: correct me please), how do I change
> permissions to that device file? So it doesn't belong to root.root, but
> to saned.saned, according to the document linked above. 
> 
> By the way: saned.saned doesn't exist, so I just created this system
> user like this:
> 
> # useradd -d /dev/null -s /bin/false saned
> 
> ... which gives:
> 
> [root at babasse 001]# cat /etc/passwd | grep saned
> saned:x:500:500::/dev/null:/bin/false
> 
> (Did I define this system user in an orthodox way? Or is there a better
> way to do this?)
> 
> Now when I su to that user and try to run scanimage -L as saned, I get a
> "No scanners were found" error, which is most likely a permission
> problem on the device. Now the big question: how do I fix this? I
> googled about "libusb hotplug scanner device permissions" and some
> permutations. The problem is not the lack of information on the subject,
> but the diverging wealth of it.
> 
> Any suggestions?
> 
> Niki Kovacs
> 
> 

I had a similar problem with an Epson Stylus CX3700 all_in_one using 
Kubuntu.

What I did was:
First add all users to the 'scanner' group; then
'sudo chgrp scanner /proc/bus/usb/001/* /proc/bus/usb/002/* -R'

(I changed both directories as I am not sure which one the scanner will 
[always] use).

This is only a temporary solution as it will revert back to root root on 
either a reboot or if you restart the scanner - so I created a 
'Bookmark' in 'Konsole' so instead of having to retype it all again I 
just click on the Bookmark and hit enter (then give my password).
You could create an alias instead though.

If you find a better solution please post it :-)

Blessings,

Nigel

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