[wellylug] Scanner permissions

[Alastair Porter]

On Mon, 2008-09-15 at 20:40 +1200, Jethro Carr wrote:
> As far as I'm aware, USB scanners do not create a device node - they are
> like ethernet cards in that respect.
I don't think this is strictly true.  Since USB Is a serial protocol
there needs to be *something* to read and write from.  There should be
at the very least something in /dev/bus/usb

> However, reading online it does appear you can configure udev to set the
> permissions for the scanners.
My Ubuntu install doesn't seem to have a permissions.d directory.
However as an example, in /etc/udev/rules.d/55-hpmud.rules:
SYSFS{idVendor}=="03f0", SYSFS{idProduct}=="??11", OWNER="lp",
GROUP="scanner", MODE="0660"

The first 2 sections identify the device, the next 3 specify the
permissions.
You can use the output of `lsusb` for the settings to use, for example:
Bus 002 Device 002: ID 045e:008c Microsoft Corp. Wireless Intellimouse
Explorer 2.0

Here, idVendor = 045e and idProduct = 008c.
There's a good introduction to udev and USB at
http://gentoo-wiki.com/HOWTO_Customizing_UDEV

Alastair

> 
> 
> Looking in the files for my CentOS 4 system:
> 
> /etc/udev/permissions.d/50-udev.permissions
> ---
> # scanner devices
> scanner:root:root:0600
> usb/scanner*:root:root:0600
> ---
> 
> I suspect that changing this should sort your problem out. :-)
> 
> The udev configuration differs from distribution to distribution, so I'm
> not sure exactly what file you need to edit for ubuntu 8.04
> 
> 
> regards,
> jethro
>