[systemd-devel] Howto detect a program/service is started by systemd?

[Stef Bon]

Hi,

it's important for a program to detect it has been started by systemd.
For example it does not have to fork since it has already been forked.

I've written a test script, which calls env, and there are a few
unique environment variables which are an indication it has been
started by systemd: SYSTEMD_EXEC_PID and INVOCATION_ID.

Is it a good way to test these environment vars (to detect started by
systemd) or is there a better way?

S. Bon