linux-kernel - Re: kill -9?

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Message-ID: <9a8748490707052335i4077fec6ofe8b37e2a86e3c8e@mail.gmail.com>
Date:	Fri, 6 Jul 2007 08:35:46 +0200
From:	"Jesper Juhl" <jesper.juhl@...il.com>
To:	"Kaleem Khan" <linuxuser8@...il.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: kill -9?

On 06/07/07, Kaleem Khan <linuxuser8@...il.com> wrote:
> Hello Kernel experts,
>
> I'd like to know whether there's a way to take some action (say
> calling a routine) in
> response to 'kill -9' before the process is terminated. I tend to
> think it's against 'kill -9'
> UNIX/Linux philosophy but still I'd like to confirm.
>
You can't catch/block SIGKILL (9), but you can catch SIGTERM (15 -
what kill sends by default).

A well behaved app should catch SIGTERM and do proper cleanup before
shutdown so that when a user does  kill <pid_of_app>  it shuts down
cleanly.  kill -9 <pid_of_app> shouldn't normally be needed - it is
for emergency termination of the app, which is why you can't catch it.

-- 
Jesper Juhl <jesper.juhl@...il.com>
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