Re: RFC: Realtime system (audio) group

[Adrian Knoth <adi@drcomp.erfurt.thur.de>]

On 01/25/2012 12:43 PM, Bastian Blank wrote:

> > [background story: pro-audio applications run with POSIX realtime
> > priorities to meet low-latency deadlines. We ship
> > /etc/security/limits.d/audio.conf in the jackd packages to grant rt
> > privileges to the audio group]
>
> Why does jackd not grant _itself_ RT priority? It can grant itself
> CAP_SYS_NICE, which allows arbitrary mangling of priorities.

   # setcap cap_sys_nice,cap_ipc_lock+eip /usr/bin/jackd

Works, but is hardly an improvement. It's either a stability risk (if
not limited) or:

> It could still limit the usage for users with the audio group and just
> drop the capability of the user is not in this group.

Which would still require the user to be part of a special group. The
audio group can't be used for this, as it would again combine "access to
sound card" and "have realtime permissions" as described in #656910.

So we're back at how to name this group. ;)


Cheers