From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/3350 Path: news.gmane.org!not-for-mail From: "Z. Gilboa" Newsgroups: gmane.linux.lib.musl.general Subject: Re: patch: make the size of errbuf configurable Date: Sun, 19 May 2013 20:09:03 -0400 Message-ID: <5199699F.4050009@eservices.virginia.edu> References: <5199324A.7020805@eservices.virginia.edu> <20130519210341.GG20323@brightrain.aerifal.cx> <51994949.1060305@eservices.virginia.edu> <20130519220941.GJ20323@brightrain.aerifal.cx> <5199517C.8040403@eservices.virginia.edu> <20130519232209.GK20323@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1369008560 10629 80.91.229.3 (20 May 2013 00:09:20 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 20 May 2013 00:09:20 +0000 (UTC) To: Original-X-From: musl-return-3354-gllmg-musl=m.gmane.org@lists.openwall.com Mon May 20 02:09:19 2013 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1UeDfD-0006MK-1j for gllmg-musl@plane.gmane.org; Mon, 20 May 2013 02:09:19 +0200 Original-Received: (qmail 14106 invoked by uid 550); 20 May 2013 00:09:18 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 14095 invoked from network); 20 May 2013 00:09:18 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130510 Thunderbird/17.0.6 In-Reply-To: <20130519232209.GK20323@brightrain.aerifal.cx> X-Originating-IP: [71.206.170.124] Xref: news.gmane.org gmane.linux.lib.musl.general:3350 Archived-At: On 05/19/2013 07:22 PM, Rich Felker wrote: > On Sun, May 19, 2013 at 06:26:04PM -0400, Z. Gilboa wrote: >>>> In my understanding, the current approach of having a fixed buffer >>>> size is by far the superior one. >>> Could you elaborate as to why? Are you concerned about memory usage? >>> Code complexity? Or some other reason? >> A little bit of both, with complexity being the main factor. As far >> as I can tell (from looking at dynlink.c and otherwise), there is >> only one case (do_relocs) where both the library name and symbol >> name are sent to the buffer. So given the case's rarity and >> singularity, I would not introduce "complex" code or memory >> allocation into the function. We should also remember that this is >> not about how the error is being handled, only about how it is being >> presented, meaning that less code is probably better... > From what I can see, complexity can be avoided and maybe even reduced > by refactoring the code so that all the places that set an error > message call a short simple function that wraps snprintf and allocates > a new buffer if needed. The complexity reduction would be if we can > eliminate duplicate logic at each call point, which I haven't checked > yet. > > Rich When moving beyond dynlink.c then yes, I believe, that should be beneficial. I just had a quick look at the places where snprintf is used, and found that the following functions might benefit from the above wrapper: dynlink.c: all functions that call snprintf syslog.c: _vsyslog getnameinfo inet_ntop (unsure) sem_open (unsure: _name_ can be up to 251 characters long (http://man7.org/linux/man-pages/man7/sem_overview.7.html), but is link to _tmp_ which is only up to 64 characters long) Zvi