Re: Should all services in rc.d support a status argument?

On Wed, Feb 19, 2025 at 6:00 PM Dan Mahoney (Ports) <freebsd@gushi.org> wrote:
>
> Hey there all,
>
> I’m in the process of implementing a nagios check at the dayjob that basically ensures that all “enabled” services are running.  (Arguably, the answer to a service that fell over is *not* always to just quietly restart it).
>
> However, not all services support the “status” command.
>
> For example, /usr/local/etc/rc.d/dma_flushq is just a hook to flush the queue on boot — it doesn’t start a process with a long-running pidfile, and since there is no pidfile listes, there’s no useful output to the “status” command, and in fact, this yields an error:
>
> # service dma_flushq status
> /usr/local/etc/rc.d/dma_flushq: unknown directive 'status'.
> Usage: /usr/local/etc/rc.d/dma_flushq [fast|force|one|quiet](start|stop|restart|rcvar|enable|disable|delete|enabled|describe|extracommands)
> # echo $?
> 1
>
> But if we take something like sshguard, then rc.subr is smart enough to look at the pidfile and figure out what I want, even though no special status command has been defined in /usr/local/etc/rc.d/sshguard:
>
> # service sshguard status
> sshguard is running as pid 814.
>
> Now, I could go through each and every service in /usr/local/etc/rc.d, and parse the auto-generated “Usage:" to see what commands they offer…
>
> # /usr/local/etc/rc.d/dma_flushq
> Usage: /usr/local/etc/rc.d/dma_flushq [fast|force|one|quiet](start|stop|restart|rcvar|enable|disable|delete|enabled|describe|extracommands)
>
> And use that to build a list of exceptions, but that’s annoying.
>
> So here’s my fun question:  For scripts that don’t *have* a status defined, should rc.subr simply return 0 with a nicer message, because it’s not a statusable service?
>
> The “practical rc.d scripting in FreeBSD” document mentions that “status” is a standard command, but is silent on this use-case.
>
> -Dan
>
> (Describe is also a valid command, but none of this stuff sets a description, even in the base OS.  I recall I took an action to make more of this stuff pass rclint).

dma_flushq isn't an actual service.  It certainly can be in
/usr/local/etc/rc.d/ to be run upon boot, but a service it is not.

As for “practical rc.d scripting in FreeBSD” document, any piece you
think is missing can always be found in the man pages:

"
If pidfile or procname is set, also support:

                 poll    Wait for the command to exit.
                 status  Show the status of the process.
"

You clearly don't have a pidfile/long standing process/etc.  It's not a service.
An exit of 1 is the appropriate exit value here.  `status` isn't valid
in these instances.
I'm not sure what you're trying to accomplish but targeted checks for
each process you know to be services should be the answer to your
problem.

~Paul
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