Re: RfD: Policy of .sh boot scripts
According to Martin Schulze:
> Miquel van Smoorenburg wrote:
> > In article <cistron.19981021122618.C23145@kuolema.Infodrom.North.DE>,
> > Martin Schulze <joey@infodrom.north.de> wrote:
> > >So regular *.sh scripts must not contain any "exit" statement.
> > >(which is the case e.g. for keymap.sh)
> >
> > Ah, now I remember. This has been solved quite some time ago.
> > *.sh scripts may contain an "exit" statement, because they are run
> > in a subshell. Fragment from /etc/init.d/rcS
>
> They don't need to be run in a subshell.
Yes they do. You reall want to be able to press Control-C to interrupt
only that fragment without killing of the whole /etc/init.d/rcS script.
For that, you need to disable SIGINT in the rcS script and run the
fragment (.sh file) in a subshell with SIGINT enabled.
That exit then also gives no problems is a nice coincidence ..
> When they would have to run in a subshell I don't see a reason for
> not making them work standalone.
sh script.sh is very different from running it in a subshell with ().
For example, bash doesn't really fork a new invocation - it just
sets up a new internal environment temporarily. It's a speed optimization.
> (Calling the user an idiot and
> preventing him from executing them manually is not a reason.)
There's no need to become abusive, even though this is the policy
mailing list :)
> Btw. when we discuss boot scripts you should not always depend on
> sysvinit owning the one and only method of booting the system.
> Please always keep in mind that there is also file-rc. There might
> be r2d2 in the future as third method.
I'm only taking Solaris as an example, because it works. But I understand
what you mean. BTW, what's r2d2?
> > Now, an exit in a subshell [ in ()] will just exit that subshell. Proof:
>
> Proof for this being not the one and only is one of the latest
> bugs agains kbd.
I bet the user who reported that bug uses an old sysvinit in which
this change wasn't made in /etc/init.d/rcS.
> > So there is no problem with exit in *.sh scripts. You can even press
> Yes there is.
No there isn't.
Mike.
--
"Did I ever tell you about the illusion of free will?"
-- Sheriff Lucas Buck, ultimate BOFH.
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