Re: What to do on ctrl-alt-del?

Miquel van Smoorenburg (miquels@cistron.nl)
15 Jul 1997 22:50:02 +0200

In article <Pine.LNX.3.95.970715194403.875A-100000@Galois.fs100.suse.de>,
Hubert Mantel <mantel@suse.de> wrote:
>Ok, this is the complete output of a typical install:
>
> PID TT STAT TIME COMMAND
> 1 ? SW 0:01 swapper
> 2 ? SW 0:00 kflushd
> 3 ? SW< 0:00 kswapd
> 4 ? SW 0:00 nfsiod
> 5 ? SW 0:00 nfsiod
> 6 ? SW 0:00 nfsiod
> 7 ? SW 0:00 nfsiod
> 8 1 S 0:01 linuxrc
> 17 ? S 0:00 update (bdflush)
> 18 2 S 0:00 bash
> 20 5 S 0:00 bash
> 21 6 S 0:00 bash
> 24 1 S 0:00 /sbin/YaST
> 42 2 R 0:02 ps -ax
>
>Linuxrc has spawned the bashes. Ok, you're right, there _is_ pid 1, but
>it is not init and it is not linuxrc. So if ctrl-alt-del is pressed, the
>machine will reboot. And you have no chance to prevent this.

What is the "swapper" process? I don't see it, neither on 2.0.30 or 2.1.44-3

[checks linux/init/main.c] ah, I see. Swapper is really pid#1, but in
kernel mode. It spawns /linuxrc, and after that exits it executes /sbin/init.
Now it's a bit more clear to me. Probably the kernel needs to be fixed
so that the SIGINT gets sent to linuxrc_pid (a new global variable) if
it is set and otherwise to process#1. That's probably the solution that
makes the most sense. Then linuxrc is free to call ctrlaltdel to setup
"soft" reboot if so required, and it can even catch SIGINT then to do
something reasonable if ctrlaltdel is pressed.

Mike.

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