[CentOS] USB scanner setup: questions, problems

Mon Jun 5 06:58:38 UTC 2006
Niki Kovacs <contact at kikinovak.net>

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