How to run a script on system shutdown/reboot

How to run a script on system shutdown/reboot

[Unstable Horse via]

Good day, people. I am browsing the shepherd's info docs, and I can't
seem to find a way to run something right after either reboot, or halt
were invoked.

Something that is usually achieved by sticking a script into /etc/rc0.d
in classical init systems, or /usr/lib/systemd/system-shutdown in
systemd.

Can I somehow configure this from my system-wide config.scm? Or any way
at all, if that's not an option?

My particular use-case is unloading a faulty kernel module, that
prevents powering off the laptop right before shepherd actually tries
to shut it down.

Re: How to run a script on system shutdown/reboot

[James Thomas]

Unstable Horse via wrote:

> Good day, people. I am browsing the shepherd's info docs, and I can't
> seem to find a way to run something right after either reboot, or halt
> were invoked.
>
> Something that is usually achieved by sticking a script into /etc/rc0.d
> in classical init systems, or /usr/lib/systemd/system-shutdown in
> systemd.

What I'd gleaned when I looked into this a while ago:

These functions are in elogind, whose hook directories are:

(PKGSYSCONFDIR = PREFIX/etc/elogind)/system-shutdown
(rootlibexecdir = (rootprefixdir = PREFIX)/lib/elogind)/system-shutdown

As of then both these directories pointed to the store build. I remember
trying to figure out whether to patch the package definition or elogind
itself, before I moved on to other things.

--

Re: How to run a script on system shutdown/reboot

[Unstable Horse]

On Sat, 2023-07-01 at 14:54 +0530, James Thomas wrote:
> What I'd gleaned when I looked into this a while ago:
> 
> These functions are in elogind, whose hook directories are:
> 
> (PKGSYSCONFDIR = PREFIX/etc/elogind)/system-shutdown
> (rootlibexecdir = (rootprefixdir = PREFIX)/lib/elogind)/system-
> shutdown
> 
> As of then both these directories pointed to the store build. I
> remember trying to figure out whether to patch the package definition
> or elogind itself, before I moved on to other things.

Thanks for the reply, I ended up solving my particular problem by
spinning up a python script shepherd service that monitors elogind for
shutdown and sleep events via D-Bus.

I've seen other people solve the same problem by creating a dummy
"sleep infinity" shepherd service, and then adding the code they want
to run on shutdown in the service's destructor (but this doesn't handle
sleep). Like this:
https://gitlab.com/nonguix/nonguix/-/issues/205#note_1253482556