Message-ID: <3AEB2B18.F1EC31DE@kegel.com>
Date: Sat, 28 Apr 2001 13:42:00 -0700
From: Dan Kegel <dank@kegel.com>
MIME-Version: 1.0
To: tmh@nothing-on.tv,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: just-in-time debugging?
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Sender: linux-kernel-owner@vger.kernel.org

 Tony Hoyle (tmh@nothing-on.tv) wrote:
> Is there a way that gdb/ddd could be invoked when a program is about 
> to dump core...?

Yes, I use that to get a symbolic stack dump after a crash,
although I find that the gdb so invoked doesn't accept interactive
commands, and I have to use 'kill -9' afterwards.
Here's the code I use:

void dump_stack(int signum)
{
    (void) signum;
    char s[160];
    // The right command to execute depends on the program.  Adjust to taste.
    system("echo 'info threads\nbt\nthread 3\nbt\nthread 4\nbt\nthread 5\nbt\n' > gdbcmd");
 
    sprintf(s, "gdb -batch -x gdbcmd %s %d", argv0, (int) getpid());
    printf("Crashed!  Starting debugger to get stack dump.  You may need to kill -9 this process afterwards.\n");
    system(s);
    exit(1);
 
} 

main() {
   signal(SIGSEGV, dump_stack);
   signal(SIGBUS, dump_stack);   
...
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