Re: System-critical package management

On Mon, Sep 18, 2023 at 12:24:20PM +0200, Guillem Jover wrote:
> While dpkg on systems using systemd _could_ by default take an
> system inhibitor lock, and could provide a good enough reason like say
> "Packaging system upgrade" or whatever, my concern has been with the
> added dependency chain, and after reading your mail and thinking about
> this now, I have to agree this seems like a higher level policy.
> (Of course dpkg could also do that and grow a new --no-inhibit,
> or --refuse-inhibit or similar option, but still.)
> 
> But then, I recalled I had a git branch adding a dpkg-db-lock command
> with a --wait-lock option, that I could recover and polish to provide
> an example pre-hook script that would call that via a background
> systemd-inhibit if systemd is running and the command is available,
> where an admin that wanted to do that for their system or fleet of
> systems could hook into the dpkg config. I've done that locally, and
> will check whether that's viable and probably merge it for 1.22.1
> or 1.22.2, so that people that want to do it can easily do so.

I'm not sure how that works because you'd need to respawn yourself
with systemd-inhibit, whereas the API essentially gives you a file
descriptor over dbus that you keep open until it is safe to reboot.