Re: emergency or init=/bin/sh mode and terminal signals

["linux-os \(Dick Johnson\)" <linux-os@analogic.com>]

On Mon, 19 Jun 2006, Samuel Thibault wrote:

> linux-os (Dick Johnson), le Mon 19 Jun 2006 07:37:02 -0400, a écrit :
>> I don't think this is the correct behavior. You can't allow some
>> terminal input to affect init. It has been the de facto standard
>> in Unix, that the only time one should have a controlling terminal
>> is after somebody logs in and owns something to control. If you want
>> a controlling terminal from your emergency shell, please exec /bin/login.
>
> Ok, but people don't know that: they're given a shell, and wonder why on
> hell ^C doesn't work...
>
> Samuel

Attached is a simple program called shell. You can copy it to /bin/shell
and use it instead of /bin/bash for your emergency shell. It provides
for terminal control, plus it protects against exit because it does
its work from a fork()ed process and if that exits another is fork()ed
forever.

It has been tested and works, however after you do your emergency
stuff, you can't (correctly) exec /sbin/init as you could with
bash alone, because the executing task does not have PID=1. Instead,
you will have to manually unmount any file-systems you mounted, then
reboot using Ctr-Alt-Del.

Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.4 on an i686 machine (5592.88 BogoMips).
New book: http://www.AbominableFirebug.com/
_



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Attachment: shell.tar.gz
Description: shell.tar.gz