[CentOS] scanner only works in su mode

Wed Sep 25 17:49:07 UTC 2013
Michael Hennebry <hennebry at web.cs.ndsu.nodak.edu>

On Wed, 25 Sep 2013, Michael Hennebry wrote:

> On Tue, 24 Sep 2013, Frank Cox wrote:
>
>> On Tue, 24 Sep 2013 17:57:12 -0500 (CDT)
>> Michael Hennebry wrote:
>>
>>> What do I change to make it let me use xsane or hp-scan as myself?
>>
>> You need to set the permission on the scanner device to allow your username to
>> use it, since it's apparently now set to allow root only.
>>
>> scanimage -L will tell you where it is.
>
> [root at localhost tmp]# scanimage -L
> device `hpaio:/usb/Photosmart_C3100_series?serial=CN6ARC321S04KV' is a Hewlett-Packard Photosmart_C3100_series all-in-one
>
> That agrees with the output from hp-scan, but it does not seem to help.
> What permissions do I change?
>
> root at localhost tmp]# find /dev -name 'Photo*'
> [root at localhost tmp]# find /usb -name 'Photo*'
> find: `/usb': No such file or directory
> [root at localhost tmp]# locate Photosmart_C3100
> [root at localhost tmp]#

This was done as root:
> I used strace on hp-scan.
> It used every "file" under /dev/bus/usb:
> [root at localhost tmp]# ls -R /dev/bus/usb
> /dev/bus/usb:
> 001  002  003  004  005
>
> /dev/bus/usb/001:
> 001  006
>
> /dev/bus/usb/002:
> 001
>
> /dev/bus/usb/003:
> 001  002
>
> /dev/bus/usb/004:
> 001
>
> /dev/bus/usb/005:
> 001
> [root at localhost tmp]#

I aso strace-d hp-scan as myself and got permission errors:
[hennebry at localhost tmp]$ grep ermission trace2.txt | sort -u | grep usb
open("/dev/bus/usb/001/001", O_RDWR)    = -1 EACCES (Permission denied)
open("/dev/bus/usb/001/006", O_RDWR)    = -1 EACCES (Permission denied)
open("/dev/bus/usb/002/001", O_RDWR)    = -1 EACCES (Permission denied)
open("/dev/bus/usb/003/001", O_RDWR)    = -1 EACCES (Permission denied)
open("/dev/bus/usb/003/002", O_RDWR)    = -1 EACCES (Permission denied)
open("/dev/bus/usb/004/001", O_RDWR)    = -1 EACCES (Permission denied)
open("/dev/bus/usb/005/001", O_RDWR)    = -1 EACCES (Permission denied)
[hennebry at localhost tmp]$

Changing the permissions on all of them seems a clunky thing to do.
Also, I do not know whether such a change would survive a reboot.

> For some reason, hp-scan also opened a lot of sane libraries,
> mostly for brands other than HP.
> hp-scan read "Photosmart C3180\n" a lot.

-- 
Michael   hennebry at web.cs.ndsu.NoDak.edu
"On Monday, I'm gonna have to tell my kindergarten class,
whom I teach not to run with scissors,
that my fiance ran me through with a broadsword."  --  Lily