non-root usb scanning

[James Wilkinson]

Peter L. Hurd wrote:
> I'm still trying to get my usb scanner to work for non-root users.

Likewise...
> 
> I've found the device file with the 0644 permissions that is causing
> the problem at /proc/bus/usb/001/002.  I can chmod that file a+rw and
> mortal user scanning works, but that needs to be re-chmodded each time
> I reboot.  I suppose I could add a line to rc.local, but that would be
> tacky, and I suppose may fail when other usb devices move around.
> 
> The solution sounds like either one of:
<snip> 
> 2) muck around with hotplug.  I honestly don't intend on hotplugging
> my scanner and the last time I mucked around with hotplug was to get
> my Axim to hotplug/synce/multisync and the whole thing just left me
> with a rash... 
 
Well, I've been looking at that, too. The first problem that I can see
is that hotplug will get at the scanner before the user gets to log in
(especially if the user leaves the computer on for a while before
logging in). So either the hotplug system or the login system is going
to have to reconfigure scanners when someone logs in.

I'm pretty sure that the hotplug system doesn't run when a new console
user logs in. And getting the login system to do it looks like you're
getting two separate mechanisms for doing the same basic thing.

John Thompson commented:
> This actually sounds like a pam configuration issue to me.  Check your
> /etc/security/console.perms file for a line like this:
> 
> <scanner>=/dev/scanner* /dev/usb/scanner*
> 
> And this:
> 
> <console>  0644 <scanner>    0644 root.users
> 
> Then pam won't change the scanner device permissions when you log in or
> out.  Change "root.users" to whatever "owner.group" you wish these
> devices to be assigned to.

Well, that inspired me to go back and check my settings.

On FC2, with USB scanners, I understand that the device node is under
/proc/bus/usb, and the kernel mode drivers are no longer used. So
/dev/scanner isn't directly used.

But if you make /dev/scanner a symlink to /proc/bus/usb/001/002, pam
will properly chmod /proc/bus/usb/001/002 when a console user logs in.
Which sounds like what Peter Hurd wanted.

Then I tried unplugging and re-plugging the scanner. It got a new device
ID in /proc/bus/usb/001/, correctly chowned and chmodded.
sane-find-scanner picked it up correctly, but scanimage -L doesn't. Ho
hum. Does anyone have a good idea for what to look at next?

James.
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