From owner-freebsd-hackers  Tue Dec  9 15:50:06 1997
Return-Path: <owner-freebsd-hackers>
Received: (from root@localhost)
          by hub.freebsd.org (8.8.7/8.8.7) id PAA18860
          for hackers-outgoing; Tue, 9 Dec 1997 15:50:06 -0800 (PST)
          (envelope-from owner-freebsd-hackers)
Received: from wafu.netgate.net (wafu.netgate.net [204.145.147.80])
          by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id PAA18802
          for <hackers@FreeBSD.ORG>; Tue, 9 Dec 1997 15:49:56 -0800 (PST)
          (envelope-from shigio@wafu.netgate.net)
Received: from chiota.signet.or.jp (INS54.tama.dti.ne.jp [210.159.144.8]) by wafu.netgate.net (8.7.5/8.7.3) with ESMTP id PAA11441; Tue, 9 Dec 1997 15:52:01 GMT
Message-Id: <199712091552.PAA11441@wafu.netgate.net>
Received: from chiota.signet.or.jp (localhost.signet.or.jp [127.0.0.1]) by chiota.signet.or.jp (8.8.5/) with ESMTP id IAA00366; Wed, 10 Dec 1997 08:46:14 +0900 (JST)
To: Andrew Kenneth Milton <akm@mother.sneaker.net.au>
cc: shigio@wafu.netgate.net, hackers@FreeBSD.ORG
Subject: Re: [RFC] path converting functions. 
In-reply-to: Message from Andrew Kenneth Milton <akm@mother.sneaker.net.au>
Sender: owner-freebsd-hackers@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk
	 
  of "Wed, 10 Dec 1997 03:16:04 +1100." <199712091616.DAA20863@mother.sneaker.net.au>
	 
Date: Wed, 10 Dec 1997 08:46:14 +0900
From: Shigio Yamaguchi <shigio@wafu.netgate.net>

> +-----[ John Polstra ]------------------------------
> | 
> | In article <199712032230.WAA28837@wafu.netgate.net>,
> | Shigio Yamaguchi  <shigio@wafu.netgate.net> wrote:
> | 
> | > 
> | > abs2rel - make a relative path name from an absolute path name
> | > 
> | > 	abs2rel(<original path name>, <base directory>, <result>);
> | > 
> | > 	<original path name>	<base directory>	<result>
> | > 	/usr/src		/etc			../usr/src
> | 
> | Since your functions write into the user-supplied buffer "result",
> | you should add an argument that specifies how big it is. 
> 
> And always return an error if they haven't allocated MAXPATHLEN :-)
> That'll teach 'em.

In realpath(3) style, it is user's responsibility to allocate a buffer
capable of storing at least MAXPATHLEN characters.
When generated path name is longer than MAXPATHLEN - 1, abs2rel and rel2abs
returns -1 and set errno = ENAMETOOLONG.
--
Shigio Yamaguchi (Freelance programmer)
	Mail: shigio@wafu.netgate.net, WWW: http://wafu.netgate.net/tama/