From mboxrd@z Thu Jan  1 00:00:00 1970
From: Michal Novotny <minovotn@redhat.com>
Subject: Re: capturing SIGKILL in DomU
Date: Tue, 05 Oct 2010 10:36:44 +0200
Message-ID: <4CAAE39C.1020708@redhat.com>
References: <AANLkTi=0bFWS0zOrD49b5iDaG3y7K_90UBCOJ+RieUvj@mail.gmail.com>
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To: "Srujan D. Kotikela" <ksrujandas@gmail.com>
Cc: xen-devel@lists.xensource.com
List-Id: xen-devel@lists.xenproject.org

Hi Srujan,
what about adding a signal handler to qemu-dm in the tools/ioemu-dir of 
the user-space tools? Using the signal() API? Nevertheless why would you 
like to catch SIGKILL? This one (as can be seen using included program 
source and killing it using kill -9 pid or kill -SIGKILL pid) is not 
being caught at all nevertheless most of the other signals can be caught.

This is the source of the example mentioned:
#include <stdio.h>
#include <signal.h>
#include <stdlib.h>

void sig_handler(int sig) {
     fprintf(stderr, "Signal %d caught.\n", sig);
     exit(sig);
}

int main()
{
     signal(SIGINT, sig_handler);
     signal(SIGKILL, sig_handler);

     sleep(10000);
     return 0;
}

When I did try SIGINT (Ctrl + C or kill -2 pid) it caught the signal 
well but when I did try kill -9 pid (or kill -SIGKILL pid respectively) 
it was not working at all since it killed the process instead of going 
to the signal handler. When you need to catch signals like interruption 
signal (Ctrl + C one) this will work fine.

Michal

On 10/04/2010 09:03 PM, Srujan D. Kotikela wrote:
> Hi,
>
> I am trying to capture SIGKILL through event channel.
>
> On my Dom0, the following process is running (remaining code in 
> attachment).
>
>
>     int main(void){
>
>         int ret, dom, remote_dom;
>
>         //initialize domains
>         dom=0;
>         remote_dom=2;
>
>         //create the event channel
>         ret = create_channel(dom, remote_dom);
>
>
>         if (0 == ret) {
>             printf("\n Event Channel established successfully \n");
>         } else {
>             return -1;    //EVENT_CHANNEL_CREATION_FAILED
>         }
>
>         //wait 20 seconds for an event to occur in DomU
>         wait_for_event(20);
>
>         //close the opened interfaces
>         close_channel();
>
>         return 0;
>
>     }
>
>
> While this process is running; I killed a process in DomU using `*kill 
> SIGKILL pid*`
>
> How can I capture this event (occured in DomU) at the Dom0. I watched 
> /dev/xen/evtchn, but no notification.
>
>
> --
> Srujan D. Kotikela
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>    


-- 
Michal Novotny<minovotn@redhat.com>, RHCE
Virtualization Team (xen userspace), Red Hat