On Wed, Dec 29, 2021 at 03:07:38AM +0100, Lorenzo wrote:
> I'm going to accept a fix for this issue, but I prefer to not have to
> parse a file and also to not add another flag file only for this, if
> it's possible.
Well, getting the first character from a file and printing it verbatim is
hardly "parsing". :)
> > #!/bin/sh
> > # /etc/runit/3 should update /run/runit.runlevel before starting stop
> > scripts unset CURLEVEL
> > CURLEVEL="$(head -c 1 /run/runit.runlevel 2>/dev/null)"
> > if [ -z "$CURLEVEL" ]; then
> > CURLEVEL=2
> > fi
> > exec printf "N $CURLEVEL"
> >
>
> Because of #1000867 I'm going to create /run/runit.reboot in stage1,
> so can't we just use stat in runlevel script (at least for runlevel 6)?
I thought of that, but I don't think it's quite this foolproof.
kexec can be critical (for example, if you have an HP raid controller in a
non-HP server, recent firmware versions hang during POST depending on BIOS
settings, even before entering the BIOS setup, so kexec may be the only way
to reboot without taking the computer apart first).
You create /run/runit.reboot once at reboot, which could have been years
ago; anything might have befallen that file in the meantime. For example, it
may not exist anymore, and 'init 6' won't create it, just set its mode if it
exists.
So far nothing depended on runit.reboot existing and having a "correct" mode
outside of runit stage 3.
We have no idea what else (other than kexec) depends on the output of
runlevel(8) and how.
I'd argue that introducing stricter requirements on the existence and
correct mode of /run/runit.reboot that apply over the whole uptime of the
system is a more dangerous and invasive change than introducing a new
control file with semantics that are obvious and well defined from the
beginning.
But, it's mostly your show: if that's how you want to do it, you obviously
can. It'll work for me.
> Something like
> #!/bin/sh
> if [ $(stat -c %a /run/runit.reboot) = 100 ]; then
> exec printf 'N 6'
> else
> exec printf 'N 2'
> fi
The problem with this is that runit hasn't so far cared about the mode of
runit.reboot before stage 3, and people may set runit.reboot to mode 100
early, for example out of a desire to make sure a box will reboot instead of
shut down if pid 1 were to receive a CONT signal for any reason.
Like I said, I think making the meaning of the mode bits of runit.reboot
meaningful in a broader context is dangerous.
> Will it work for kexec?
It should. (You'll want a 2>/dev/null on the stat(1) invocation for cases
where the file doesn't exist, /run isn't mounted etc.)
> Also, do we have to cover the 'N 0' shutdown case because of some
> other init scripts that you know of?
I'm not aware of any, but then I didn't know about kexec a week ago, so this
doesn't necessarily mean anything. :)
András
--
What if the lottery was just invented by the government
to capture time travelers?
