From owner-freebsd-bugs  Tue Nov  3 16:30:03 1998
Return-Path: <owner-freebsd-bugs@FreeBSD.ORG>
Received: (from majordom@localhost)
          by hub.freebsd.org (8.8.8/8.8.8) id QAA13832
          for freebsd-bugs-outgoing; Tue, 3 Nov 1998 16:30:03 -0800 (PST)
          (envelope-from owner-freebsd-bugs@FreeBSD.ORG)
Received: from freefall.freebsd.org (freefall.FreeBSD.ORG [204.216.27.21])
          by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id QAA13773
          for <freebsd-bugs@FreeBSD.org>; Tue, 3 Nov 1998 16:30:00 -0800 (PST)
          (envelope-from gnats@FreeBSD.org)
Received: (from gnats@localhost)
	by freefall.freebsd.org (8.8.8/8.8.5) id QAA17144;
	Tue, 3 Nov 1998 16:30:01 -0800 (PST)
Received: from whistle.com (s205m131.whistle.com [207.76.205.131])
          by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id QAA12942
          for <FreeBSD-gnats-submit@freebsd.org>; Tue, 3 Nov 1998 16:23:27 -0800 (PST)
          (envelope-from archie@whistle.com)
Received: (from smap@localhost) by whistle.com (8.7.5/8.6.12) id QAA19252 for <FreeBSD-gnats-submit@freebsd.org>; Tue, 3 Nov 1998 16:23:15 -0800 (PST)
Received: from bubba.whistle.com(207.76.205.7) by whistle.com via smap (V1.3)
	id sma019248; Tue Nov  3 16:22:58 1998
Received: (from archie@localhost) by bubba.whistle.com (8.8.7/8.6.12) id QAA16848; Tue, 3 Nov 1998 16:22:57 -0800 (PST)
Message-Id: <199811040022.QAA16848@bubba.whistle.com>
Date: Tue, 3 Nov 1998 16:22:57 -0800 (PST)
From: Archie Cobbs <archie@whistle.com>
Reply-To: archie@whistle.com
To: FreeBSD-gnats-submit@FreeBSD.ORG
X-Send-Pr-Version: 3.2
Subject: bin/8566: mergesort() core dumps if number of elements is zero
Sender: owner-freebsd-bugs@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.org


>Number:         8566
>Category:       bin
>Synopsis:       mergesort() core dumps if number of elements is zero
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:
>Keywords:
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Nov  3 16:30:01 PST 1998
>Last-Modified:
>Originator:     Archie Cobbs
>Organization:
Whistle Communications, Inc.
>Release:        FreeBSD 2.2.6-RELEASE i386
>Environment:

	FreeBSD 2.2-stable AND 3.0-current

>Description:

	If meregsort() is called with number of elements == 0,
	it will still try to compare them (!), causing a core
	dump or worse.

>How-To-Repeat:

    Compile and run this program:

	#include <stdlib.h>
	#include <stdio.h>

	static int
	compare(const void *v1, const void *v2)
	{
	  return(*((int *) v1) - *((int *) v2));  
	}
	   
	int
	main(void)
	{ 
	  int   *array = NULL;
	  
	  if (mergesort(array, 0, 4, compare) < 0)
	    err(1, "mergesort");
	}

>Fix:

NOTE: Please fix this in BOTH 2.2 and 3.0.. thanks!
	
Index: merge.c
===================================================================
RCS file: /cvs/freebsd/src/lib/libc/stdlib/merge.c,v
retrieving revision 1.2
diff -u -r1.2 merge.c
--- merge.c	1995/05/30 05:41:50	1.2
+++ merge.c	1998/11/04 00:19:56
@@ -111,6 +111,9 @@
 		return (-1);
 	}
 
+	if (nmemb == 0)
+		return (0);
+
 	/*
 	 * XXX
 	 * Stupid subtraction for the Cray.
>Audit-Trail:
>Unformatted:

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-bugs" in the body of the message