User on client cannot access scanner connected to server

[Sotir Rangelov]

I installed out of the box Ubuntu 8.04 Server, then install ubuntu-desktop, then I installed LTSP following instructions here:
https://help.ubuntu.com/community/ThinClientHowto

1) The release of Ubuntu:
Ubuntu 8.04

2) The version of the package:

ltsp-server-standalone:
  Installed: 5.0.40~bzr20080212-0ubuntu7
  Candidate: 5.0.40~bzr20080212-0ubuntu7
  Version table:
 *** 5.0.40~bzr20080212-0ubuntu7 0
        500 http://bg.archive.ubuntu.com hardy-updates/main Packages
        100 /var/lib/dpkg/status
     5.0.40~bzr20080212-0ubuntu6 0
        500 http://bg.archive.ubuntu.com hardy/main Packages

3) What I expected to happen:

Connect a scanner to the server. Then log in on the client and use that scanner.

4) What happened instead:

The client cannot find the USB scanner connected to the server, though the scanner works from the server.

I noticed that if I run in terminal (on the client):
scanimage -L

it founds nothing. But if I run:
sudo scanimage -L

the scanner is found. I also can use it but through:
sudo xsane

Please, note that this same user is administrator and if I log in on the server I can see and use the scanner.

5) What I did to solve the issue

I checked ownership and group of scanner and it was:
ls -l /dev/bus/usb/001
total 0
crw-rw-r-- 1 root root 189, 0 2009-01-29 21:54 001
crw-rw-r-+ 1 root root 189, 22 2009-02-01 13:59 023

023 is the scanner

I identified two combinations as a solution:
A. Change group to Scanner, or
B. Change permissions for Others to Read and Write

[Sotir Rangelov (rangelov)]

I noticed that this solution is only temporary. After a restart the permissions are set to root again. I guess it is the way it should be. I will be grateful if someone provides a permanent solution. Thank you.

[Sotir Rangelov (rangelov)]

I made some tests. Here are the results:

1. I installed Ubuntu 8.04 Desktop and ltsp-server-standalone. The scanner is accessible from the server, but not from the client.

2. I installed Ubuntu 7.10 Desktop and ltsp-server-standalone. The scanner is accessible from the server and from the client - as it should be!
Then I upgraded to Ubuntu 8.04 and the scanner is no more accessible.

Any information how to solve this is welcome. Thank you in advance!

[Sotir Rangelov (rangelov)]

Here is a more permanent solution:
Create a udev rule. My /etc/udev/rules.d/42-local.rules contain the following:

--------------
# This rule sets scanner's group to "scanner", allowing LTSP users to use the scanner on the server.

SUBSYSTEM=="usb", ATTR{idVendor}=="04a9", ATTR{idProduct}=="2220", SYMLINK+="%k", GROUP="scanner"
---------------

To find out how to do it, visit:

http://my.oltrans.org/en/ubuntu-faqs/41-customizing/66-ltsp-thin-clients.html

Sotir

P.S. This issue still needs Ubuntu geeks attention :)

[Stéphane Graber (stgraber)]

Is that still the case with more recent LTSP like 9.04 or ideally 9.10 ?
I'd suspect some consolekit issue to change the ACL on these files but would like to have feedback with current LTSP (especially as we now have scanner support on the thin client as well).

[Launchpad Janitor (janitor)]

[Expired for ltsp (Ubuntu) because there has been no activity for 60 days.]