Re: spiped process matching on OpenBSD

[Graham Percival <gperciva@tarsnap.com>]

Hi Jared,

Sorry if this seems like "too obvious" of a solution, but have you tried
escaping the square brackets with \ ?  i.e.

    pexp="${daemon} -s \[127.0.0.1\] .*"

or something like that?

I'm not familiar with rc files, so it's possible that they use a different
character for escaping, but I'm certain they have that capability somehow.

Cheers,
- Graham

On Sat, Apr 08, 2023 at 03:22:25PM -0700, Jared Harper wrote:
> 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