systemd questions

Michal Hlavinka mhlavink at redhat.com
Tue May 17 13:42:33 UTC 2011


> > 5) in old initscripts, there was /etc/init.d/halt with section for ups
> > shutdown. With that script gone, was that functionality ported to
> > systemd
> > somehow?
> 
> Well, any such code is just inherently broken. It *cannot* work. A
> number of kernel subsystems hook into the shutdown code of the
> kernel. For example storage code syncs meta data to disk after the
> reboot() syscall is invoked. If you however turn off power before
> reaching reboot(), then this step is omitted which might trigger data
> loss. UPS code like that needs to sit in the kernel itself to properly
> work. Adding userspace kludges which invokes this from userspace is a
> recipe for desaster. The point of UPS is to prevent data loss after all,
> and if you turn off the power before the kernel dealt with reboot() you
> invite data loss. (And no, just adding random sleeps, is not a fix, it
> just delays the problem.)
> 
> (That all said you may drop binaries into /lib/systemd/system-shutdown
> which are executed right before invoking reboot(). But if you package
> anything that drops binaries into that dir 
...

how can automake & friends use this directory?

FOO=$(pkg-config --variable=systemdsystemunitdir systemd)/../system-shutdown
(or FOO=$(dirname $(pkg-config --variable=systemdsystemunitdir systemd) 
)/system-shutdown
 or is there a better way for this?


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