question on SCSI-scanners

[Kay Sievers]

On Sun, Jan 4, 2009 at 20:08, Dieter Jurzitza
<dieter.jurzitza at t-online.de> wrote:
> imagine I have a SCSI-scanner that is detected and listed by hald, because to
> my current understanding the udev - event of generated device-nodes is being
> passed to hald (?).
>
> Now, what steps would be neccessary to make this device accessible to a
> regular user? Initially the permissions come up with
>
> /dev/sg2  root.root 0660
>
> what clearly excludes anyone except root from accessing this device. If I
> understood correctly an acl-rule would be required?
>
> Is there any good reason to create the device like this (i.e. owner / group
> root.root) in contrast what happens usually to usb-scanners (root.lp /
> root.scanner)?
>
> Could some nice soul provide some hints how to dig into this xml-stuff and to
> understand _what_ needs to happen in order to provide the user access and how
> this is happening?
>
> Any pointer is highly appreciated. Most documentation refers to block devices
> and mounting - but I have a character device here and the only task that
> needs to be accomplished is to provide access to users besides root.
>
> The latest opensuse distribution unfortunately does not provide any access to
> a scsi-scanner but through the net-interface via localhost for non-root
> users - what seems like "from one's back through the chest into the eye" to
> stress a German saying - it is complicated and hard to explain to anyone.
>
> By the way: I have tried to read David Zeuthen's article on hal (Desktop And
> Hardware Configuration) that says pci, usb, block and net devices are handled
> (but I'm talking about a character special device, right?), I've been looking
> into "Making Hardware Just Work" by Havoc(?) and "HAL and device management"
> from www.mythic-beasts.com/~mark/random/hal, but I haven't got a clue so far
> on how to proceed here.
>
> The documentation within the hal-sources is difficult to understand, basically
> I'd have to understand the source code.
>
> Any help, any suggestions are largely appreciated,
> thank you for taking the time to read,

Right, you need an ACL on the device node, and we need to find out
that the SCSI device is a scanner. Let's take a look at the device,
and se what we can match against. What does:
  /sbin/udevadm info --attribute-walk --name=/dev/sg2
print?

Kay