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Date: Fri, 10 May 2013 13:09:43 +0200
Message-ID: <CAJSP0QVcmySJSwcXLLTPdiwFUYR-OLjTJan+V0M3QSn9AAV5iQ@mail.gmail.com>
From: Stefan Hajnoczi <stefanha@gmail.com>
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Subject: Re: [Qemu-devel] kvm process disappears
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To: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
Cc: qemu-devel <qemu-devel@nongnu.org>, "pve-devel@pve.proxmox.com" <pve-devel@pve.proxmox.com>

On Fri, May 10, 2013 at 11:07 AM, Stefan Priebe - Profihost AG
<s.priebe@profihost.ag> wrote:
> Am 10.05.2013 09:42, schrieb Stefan Hajnoczi:
>> On Fri, May 10, 2013 at 08:12:39AM +0200, Stefan Priebe - Profihost AG wrote:
>> 3. Either use gdb or an LD_PRELOAD library that catches exit(3) and
>>    _exit(2) and dumps core using abort(3).  Make sure core dumps are
>>    enabled.
>
> LD_PRELOAD sounds good can you point me to such a lib?

$ cat /tmp/catchexit.c
#include <unistd.h>
#include <stdlib.h>

void exit(int status)
{
    const char msg[] = "*** CAUGHT EXIT, DUMPING CORE ***\n";
    write(2, msg, sizeof msg);
    abort();
}

void _exit(int status) __attribute__((alias("exit")));

$ gcc -o catchexit.so -shared -fPIC -std=gnu99 catchexit.c

$ LD_PRELOAD=/tmp/catchexit.so x86_64-softmmu/qemu-system-x86_64 -m
1024 -enable-kvm -cpu host -vga asdf
Unknown vga type: asdf
*** CAUGHT EXIT, DUMPING CORE ***
Aborted (core dumped)

Make sure to give the absolute path to catchexit.so.  Also keep in
mind that this does not catch a normal return from main() or possibly
other ways of terminating the process.

You can hook more library functions, if necessary.

Stefan