Activity Light

We would like our LinuxCNC system to control an activity light. This would be a red light on the machine active when the motors are engaged. Does LinuxCNC already have a feature to control such a thing? Where should I look to find the interface?
We are using a Mesa board and a Raspberry Pi. Can I route a control signal through to an output pin on the Mesa board?

Thank you.

Usable hal pins
amplifier-enable
machine-is-on
e-stop-out
x-enable
something like this
x-enable hm2_7i76e.0.7i76.0.0.output-00
Replace board and pins accordingly.

Maybe the hal pin "halui.program.is-running" might be more like what he is after?

Thanks, that's exactly what I'm looking for. We'll be experimenting with it.