kill -9?

kill -9?

[Kaleem Khan]

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.

Thank you.

Re: kill -9?

[Jesper Juhl]

On 06/07/07, Kaleem Khan <linuxuser8@gmail.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@gmail.com>
Don't top-post  http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please      http://www.expita.com/nomime.html

Re: kill -9?

[Denis Vlasenko]

On Friday 06 July 2007 08:35, Jesper Juhl wrote:
> On 06/07/07, Kaleem Khan <linuxuser8@gmail.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.

Tell that to Oracle. They believe that they are above any rules
and conventions. TERM does not terminate oracle db.

I tried to explain to Oracle DBAs I met how terribly wrong is it.
Quite frustrating experience.
--
vda