[systemd-devel] 70-uaccess.rules: add new ID_SDR_HW?

[Zbigniew Jędrzejewski-Szmek]

On Mon, Jul 14, 2014 at 07:40:10PM +0800, Alick Zhao wrote:
> Hi all,
> 
> I am recently playing with software
> defined radio (SDR) hardwares (USRP, bladeRF, etc.),
> and come across the plugdev group issue. It seems the best way is to
> write a local rule
> saying something like: [1]
> 
>   SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", \
>     ATTRS{idVendor}=="xxxx", ATTRS{idProduct}=="yyyy" \
>     ENV{ID_<some_name>}="zzzz"
> 
> and to rely 70-uaccess.rules [2] to grant the permission.
For logind to grant permissions, *something* has to set the uaccess tag.
This can be done in 70-uaccess.rules, but it could also be done
in rules delivered by a different project.

> However, it seems there is no proper ID for SDR hardware for the
> moment, so I have to
> write TAG+="uaccess" directly in local rule file. AFAIK it is not recommended.
I don't see why that should be bad.

> So is it possible to add ID_SDR_HW in the 70-uaccess.rules file?
It could be done. Whether systemd is the best place to keep the rules
for SDR depends on whether there's a better project, like sane for scanners,
etc.

> You may suggest a better name of course.
Something longer would be better.

> Besides, I see there are inconsistency of ENV{ID_<some_name>} in [2]
> ("*?" vs "?*").
> Do they match different things? Hope you can clarify.
They are equivalent and both match a string with a least one character.

Zbyszek