Tearing down the system

[Scott James Remnant]

For edgy we're going to be attacking the init scripts that perform
something on shutdown (rc0.d) or reboot (rc6.d) that is completely
un-necessary.

The specification for that is:

	http://wiki.ubuntu.com/Teardown


Broadly speaking, if you have a package in Ubuntu with an init script,
you should question whether it really needs to run in these two run
levels.

If your script does nothing more for the "stop" argument than:

 * Send a TERM signal to the process.

 * Wait using sleep (and not any further checking, such as against a
   queue or similar)

 * Send a KILL signal to the process.

Then it should NOT have a symlink in rc0 or rc6.

Currently most scripts only do the first thing, and some don't even do
that and just exit if "stop" is given as the argument.  This is a waste
of time, as this is performed by the sendsigs script anyway.

Also if your script does something that's reasonably pointless given the
machine is about to go away, such as clean up files in /var/run (a
tmpfs), /var/lock (also a tmpfs), etc. it should not have a symlink in
these run levels either.


Changing your package is easy, you're probably calling the following in
your debian/rules:

	dh_installinit
or
	dh_installinit defaults

Change that to

	dh_installinit multiuser


Maybe you're calling update-rc.d in your postinst instead, change:

	update-rc.d foo defaults

to

	update-rc.d foo multiuser


If you're using more complicated arguments, make sure you drop "0" and
"6" from the list of runlevels for "stop", e.g.:

	update-rc.d foo start 35 2 3 4 5 . stop 65 0 1 6 .

becomes

	update-rc.d foo start 35 2 3 4 5 . stop 65 1 .


Be sure to remove up the old symlinks from /etc/rc0.d and /etc/rc6.d in
your postinst if your package is upgraded.

Scott
-- 
Scott James Remnant
scott at ubuntu.com
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