From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gdb-return-29734-listarch-gdb=sources.redhat.com@sourceware.org>
Received: (qmail 24994 invoked by alias); 28 Sep 2007 00:25:41 -0000
Received: (qmail 24970 invoked by uid 22791); 28 Sep 2007 00:25:40 -0000
X-Spam-Check-By: sourceware.org
Received: from fk-out-0910.google.com (HELO fk-out-0910.google.com) (209.85.128.191)     by sourceware.org (qpsmtpd/0.31) with ESMTP; Fri, 28 Sep 2007 00:25:37 +0000
Received: by fk-out-0910.google.com with SMTP id 26so2563694fkx         for <gdb@sourceware.org>; Thu, 27 Sep 2007 17:25:34 -0700 (PDT)
Received: by 10.82.178.11 with SMTP id a11mr5938662buf.1190939133711;         Thu, 27 Sep 2007 17:25:33 -0700 (PDT)
Received: by 10.82.108.11 with HTTP; Thu, 27 Sep 2007 17:25:33 -0700 (PDT)
Message-ID: <4dcb5abd0709271725v73cdf443q46fb43c985474c21@mail.gmail.com>
Date: Fri, 28 Sep 2007 01:23:00 -0000
From: "Carl Shapiro" <carl.shapiro@gmail.com>
To: "Mark Kettenis" <mark.kettenis@xs4all.nl>
Subject: Re: Problems with hook-stop
Cc: gdb@sourceware.org
In-Reply-To: <200709271127.l8RBRMPG017896@brahms.sibelius.xs4all.nl>
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
References: <4dcb5abd0709260133h10aede86wb60a22094c8d9884@mail.gmail.com> 	 <200709271127.l8RBRMPG017896@brahms.sibelius.xs4all.nl>
X-IsSubscribed: yes
Mailing-List: contact gdb-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <gdb.sourceware.org>
List-Subscribe: <mailto:gdb-subscribe@sourceware.org>
List-Archive: <http://sourceware.org/ml/gdb/>
List-Post: <mailto:gdb@sourceware.org>
List-Help: <mailto:gdb-help@sourceware.org>, <http://sourceware.org/ml/#faqs>
Sender: gdb-owner@sourceware.org
X-SW-Source: 2007-09/txt/msg00237.txt.bz2

On 9/27/07, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> Since SIGTRAP has a very special meaning for debugging, it's probably
> unwise to play games like this.

The problem I am having is not specific to SIGTRAP.  You can replace
the interrupt instruction with a kill(2), providing any signal you'd
like as an argument.  The stop hook will fails execute every other
time.

Here's the hook-stop definition to use:

define hook-stop
  signal SIGUSR1
end

Here's the program to run under GDB:

#include <signal.h>
#include <stdio.h>
#include <unistd.h>

void handler(int signum) {
 fprintf(stderr, "handler(signum=%d)\n", signum);
}

int main(int argc, char *argv[]) {
 struct sigaction sa;
 int i;
 sa.sa_handler = handler;
 sigaction(SIGUSR1, &sa, NULL);
 for (i = 0;; ++i) {
   fprintf(stderr, "i=%d\n", i);
   kill(getpid(), SIGUSR1);
 }
 return 0;
}