Subject: Re: ctrl+alt+del
To: NetBSD User's Discussion List <netbsd-users@NetBSD.ORG>
From: Greg A. Woods <email@example.com>
Date: 06/11/2001 15:52:10
[ On Sunday, June 10, 2001 at 23:53:36 (-0400), David Maxwell wrote: ]
> Subject: Re: ctrl+alt+del
> Well, that leaves open a whole discussion about where userland's border
> is, wrt 'init'. :-)
I don't think there's any question there. Init is firmly and solidly a
100% user-land process. (It just happens to be the "first" process but
from the time the "creates" process #1 and sets it up to exec /sbin/init
it never ever again runs in kernel space.)
> That would need to be settable as well. The people arguing for CAD
> to allow convienient shutdown via the remote-hands protocol, may not
> want to open their console to the messing that can be done with DDB. DDB
> may also not be compiled in.
If there's no DDB compiled in then there are a zillion and one other
ways to safely shut down the machine from user-land; and an order of
magnitude more ways to invoke them without having to have the console
driver learn any magic and/or send any signals to init.
Or are you saying instead that there should always be a way to trigger a
kernel sync and reboot from the console without going to userland?
I'm not entirely opposed to having stand-alone kernel-only reboot
trigger support in the console, just so long as it asks me nicely
whether I really mean it or not and will go back to normal operation if
I say "no" (i.e. just like BSD/OS does). I just don't think it's really
that important an option given that 99.999% of the times it's needed it
can be provided by DDB, and I think it would have to be a kernel
compile-time _option_ anyway, even on i386.
Greg A. Woods
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