Improving halt package interaction...

[Thomas M Steenholdt]

Hi all...

I'd like to bring up a suggestion that would make it easier for 
packagers to modify the halt process, without resorting to changing 
files owned by other packages.

Currently /etc/init.d/halt provides a hook into the halt process via an 
/sbin/halt.local file. If this file exists and is executable, it will be 
run during the halt process. This makes it possible for system 
administrators to write their own halt modifier (typically needed when 
dealing with UPSes and possibly other types of packages).

I think it would be very valuable to extend this functionality of 
/etc/init.d/halt to support a /etc/halt.d/ directory in addition to the 
halt.local script (Why is halt.local currently not located in /etc along 
with rc.local and such but in /sbin btw?). This would allow a package 
(an UPS software package as an example) to drop a halt modifier script 
in /etc/halt.d/ to take care of prepping the system for halt (rather 
that poweroff) and initiate a delayed UPS poweroff, if a mains powerloss 
condition was detected. Currently the package will have to hack either 
/sbin/halt.local, which could be difficult, or /etc/init.d/halt which 
would be just plain bad. Usually they will simply leave this out and the 
system admin will have to set it up manually, for the UPS to work properly.

The current version of the /etc/init.d/halt script (from 
initscripts-8.60-1) includes UPS handling code for the NUT UPS 
software(i think). NUT could easily be made to use the new /etc/halt.d/ 
infrastructure too, and /etc/init.d/halt could get rid of the 
non-generic UPS handling code, which IMHO should be avoided anyway...

What do you guys think about this?

/Thomas