rc script: manual stop vs system shutdown

[Konstantin Belousov]

On Mon, Aug 12, 2019 at 10:46:29AM +0300, Andriy Gapon wrote:
> On 01/08/2019 22:51, Ian Lepore wrote:
> > On Thu, 2019-08-01 at 21:14 +0300, Andriy Gapon wrote:
> >> On 01/08/2019 19:12, Warner Losh wrote:
> >>>
> >>>
> >>> On Thu, Aug 1, 2019, 10:53 AM Rodney W. Grimes
> >>> <freebsd-rwg at gndrsh.dnsmgr.net <mailto:freebsd-rwg at gndrsh.dnsmgr.net>>
> >>> wrote:
> >>>
> >>>     >
> >>>     > Is it possible in an rc script to distinguish between a manual stop
> >>>     > (e.g., service foo stop) and a stop during a system shutdown (via
> >>>     > rc.shutdown) ?
> >>>     > Are there any marker variables for that?
> >>>     > Or something in the global system state?
> >>>
> >>>     Not that I can think of, but I like this idea,
> >>>     I am sure that use cases exist.
> >>>
> >>>
> >>> What is the use case that needs to disambiguate the two cases...
> >>
> >> I have one use case in mind and it's a truly special case.
> >> I want rc.d/watchdogd to gracefully stop watchdogd and to disable the
> >> watchdog timer when the stop action is requested manually.  And I want
> >> it to stop watchdogd and set the watchdog timer to a special shutdown
> >> timeout during the shutdown.  If the special timeout is configured, of
> >> course.
> >>
> > 
> > The shutdown timeout is already supported:  you just set '-x <timeout>'
> > in watchdogd_flags in rc.conf; no changes to the rc.d script needed.
> > 
> > I think probably you don't even need the first part of what you want. 
> > The -x arg covers you in the reboot case; most people probably won't
> > use it.  But if you are using it, and you want to truly kill the dog,
> > you would just do "watchdog -t 0" after "service watchdogd stop".  If
> > you really felt the need to cover that with a single service command,
> > then how about using "service watchdogd cancel" where the cancel verb
> > does the -t 0 after killing the daemon?
> 
> I guess that there is more than one way to achieve what I want or
> something similar to that.
> Rather than "expend words" on a theoretical discussion, I decided to do
> this: https://reviews.freebsd.org/D21221
> However, I am still open to the discussion and suggestions.
> One thing that I would prefer, though, is to make the watchdogd service
> as smart as possible -- but not smarter :-) -- that is, I would prefer
> to do without adding any new command verbs to it.

Did you considered exporting kern_shutdown.c:rebooting as a sysctl ?