[systemd-devel] logind: support of shared devices

[Oleg Samarin]

> > After adding the simple udev rule:
> >
> > ----------------------------------------------
> > KERNEL=="seq", SUBSYSTEM=="sound", TAG+="shared"
> > ----------------------------------------------
> >
> > /dev/snd/seq becomes accessible from all seats.
> >
> > Could you resolve this patch upstream or propose another way of granting
> > access to /dev/snd/seq on activating sessions?
> 
> Why not remove the "uaccess" TAG from the device and set your own
> permissions? Like:
> 
> TAG-="uaccess", MODE=whatever, GROUP=something
> 
> This way, logind will never touch the device and your statically set
> access-rules will be applied. If you now set the group to your
> user-group, only your user will have access to the device, regardless
> of the seat it's on.

1. "uaccess" tag is added by another udev rule, and I do not know, what
will happen if there are two rules in contradiction
2. By default /dev/seq/snd belongs to the "audio" group. Changing it may
be unsafe fore some applcations.
3. Static access rules do not regard on whether the session is active or
not. I want that the access would be granted only to users that have
active sessions.