Comment 1 for bug 1418474

Devananda rightly pointed out that SIGHUP is not the right to for the job.

The way I see it there are two main options:

1. A trigger that causes the process to shutdown without deregistering itself.
2. A trigger that causes the process to avoid deregistering itself when it is shutdown.

I favour the second approach, as it avoids giving a new purpose to an existing signal.

The mechanism for the trigger could be:

- A signal e.g. SIGUSR1/2.
- The existence of a file, possibly with some particular contents or name to ensure it is intended for that process.
- An API call.

The simplest option is the first, and I think think has some merit. It's main drawback is the lack of available signals, which might be reissued for other purposes in future.