spiped process matching on OpenBSD

["Jared Harper" <jared@hrpr.us>]

I have spiped running on two OpenBSD 7.2 hosts, installed via `pkg_add`,
and it works great.

The port's rc script for spiped, however, is only usable for a single
instance because it sets `pexp="${daemon} .*"`[1], which will match
every running instance of spiped. 

(For those unfamiliar with `pexp`, it is the regex used to identify a
running process via `pgrep`. OpenBSD's rc system relies on this process
matching method and does not support pid files.)

I spent some time trying to configure the pexp to not be so greedy by
using the default `${daemon} ${daemon_flags}`.  This approach is
unsuccessful due to the brackets surrounding the IP address (e.g.,
`[127.0.0.1]`) becoming a regex matching list.

Some options I could use to workaround this limitation:

1) Use hostnames and no brackets; This apparently works but it limits
usefulness.

2) Manually set `pexp`; This does work but requires that I remember to
update it whenever the `daemon_flags` change. Also, across multiple
processes this becomes borderline umaintainable.

(Unfortunately, using the pidfile is a no-go because of how the rc
subroutines use `pexp` in multiple places.)

Since the primary author of spiped is a long-time contributor to
FreeBSD, and FreeBSD supports pidfiles in their rc-system[2], I want to
be clear I'm not saying that spiped does anything wrong, or that OpenBSD
is doing something right. I just want to come up with a solution that I
can contribute to the OpenBSD port so that we don't have to have this
issue.

A potential solution I can see would be to support `setproctitle(3)`[3]
via a flag, such as `--name <name>`, which could result in a process
title like `spiped: myname`.  What's the appetite for this sort of
change?

However, since I'm new to a lot of these technologies, I'm fairly
certain I've missed something obvious or easy (other than "switch to
FreeBSD" ;). Do you have any other ideas? 

Thanks in advance. 

[1]: https://github.com/openbsd/ports/blob/master/security/spiped/pkg/spiped.rc#L9
[2]: https://man.freebsd.org/cgi/man.cgi?rc.subr(8)
[3]: https://man.freebsd.org/cgi/man.cgi?query=setproctitle&sektion=3&format=html

-jh