Systemd unit file: Can/Should ExecStart and ExecStop run a script?

Kay Sievers kay.sievers at
Wed Oct 19 21:25:06 UTC 2011

On Wed, Oct 19, 2011 at 22:26, Lennart Poettering <mzerqung at> wrote:
> On Wed, 19.10.11 13:43, Richard Shaw (hobbes1069 at wrote:
>> It looks like I'll be taking over mythtv packaging for RPM Fusion and
>> I noticed it still only uses a sysv init script.
>> In the sysv script it sets some ACL permissions on video and audio
>> devices necessary for the backend service, and then on shutdown
>> changes it back.
>> I don't see any way to accomplish this in a systemd unit file other
>> than running a script.
>> What's the right way to do this? I have a template unit file (not
>> meant to "work" yet):
> You should manage acess control of device nodes from udev rules. That's
> the only reasonably safe way to handle these things. And this should not
> be mentioned at all in systemd unit files.

All video and audio devices have a proper default group ownership.
These groups exist only for system daemons like this.

System groups are not supposed to be used by users. There is no
support for ACLs setups for system services. ACLs are usually used for
logged-in users only.

Just put the user the process runs with in the audio and video group.


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