udev rules

[Loïc Minier]

Hi!

I saw a couple of software pieces that rely on udev rules to work; I guess
these use cases need design to be supported in snaps; I wanted to share
some specifics below.

1) aksusbd is a Gemalto daemon to assert presence of a license USB dongle;
it requires USB access, and also these udev rules that call binaries on
addition/removal of devices and create /dev symlinks:
http://www.feflow.info/download/FEFLOW/linux/dongle-2.41/linux_dinst/hasp.rules

This is a dependency of e.g. Quortus EPC (4G core network). It could be
delivered as a part or more likely as a separate snap since Quortus can
operate in different modes.

2) LimeSDR is SDR hardware that comes in USB and PCI form-factor. It might
be used from desktop apps, e.g. Gqrx is a spectrum exploration tool and
typically a desktop app that runs as non-root. This is the set of udev
rules that upstream recommends installing:
https://github.com/myriadrf/LimeSuite/blob/master/udev-rules/64-limesuite.rules

These two use cases (triggering commands when devices are plugged /
unplugged and granting permissions to desktop users to a new /dev node)
don't seem possible right now. I think the former is probably covered in
hotplugging requirements, not sure about the latter. Perhaps I should add
these to some existing design doc?

Thanks,
- Loïc Minier