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

[Richard Shaw]

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):

[Unit]
Description=MythTV backend service
After=mysqld.service

[Service]
Type=forking
PIDFile=/var/run/mythbackend.pid
ExecStart=/bin/sh /usr/libexec/mythtv/startmythbackend.sh
ExecStop=/bin/sh /usr/libexec/mythtv/stopmythbackend.sh

[Install]
WantedBy=multi-user.target

Thanks,
Richard