From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1bChn0-0004ev-3t for barebox@lists.infradead.org; Tue, 14 Jun 2016 06:25:31 +0000 Date: Tue, 14 Jun 2016 08:25:06 +0200 From: Sascha Hauer Message-ID: <20160614062506.GO31666@pengutronix.de> References: <20160613105152.28770-1-aar@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20160613105152.28770-1-aar@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH RFC] common: env: handle var="" not as var=NULL To: Alexander Aring Cc: barebox@lists.infradead.org On Mon, Jun 13, 2016 at 12:51:52PM +0200, Alexander Aring wrote: > This patch changes the behaviour which I think is used everywhere in > barebox code. Currently var="" and var=NULL will end in the same > behaviour. > > New behaviour is: > > setenv(name, "") -> sets name to "" > \-> getenv(name) -> "" > > setenv(name, NULL) -> deletes env > \-> getenv(name) -> NULL > > It seems that barebox code already wants such behaviour, by run > > $ grep -r "\"\"" | grep setenv > > it finds most all related code sections which use "". > > I detected the issue while commenting #ip="foo" in my env. The code > part: > > net/ifup.c: setenv("ip", ""); > > Sets at first "ip" to "" but will end in the old behaviour as "delete". > The getenv("ip") in ifup.c will not check on the NULL value and has a > general handling for unknown ip env. > > Note: > Also check commit e7ed69d5 ("setenv: be robust against setenv(, > NULL") which says that hush will handle "" and NULL as the same. > > Another check would be: > > $ grep -r "NULL" | grep setenv > > which should show the behaviour in case of deleting env. > > Signed-off-by: Alexander Aring > --- > I test the ip env stuff only that barebox will not crash anymore but I > think it will break some other setenv/getenv behaviour. > > The question is "Shall we keep that "" and NULL ends in same behaviour" > and fix the code which use it wrong, e.g. setenv("ip", ""); getenv("ip"). I'm not sure at the moment if a var="" should delete a variable or just set it to an empty string. In any case we should fix net/ifup.c. getenv() can return NULL and the code should be prepared for that. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox