From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31967 invoked by alias); 7 Mar 2012 20:41:14 -0000 Received: (qmail 31959 invoked by uid 22791); 7 Mar 2012 20:41:14 -0000 X-SWARE-Spam-Status: No, hits=-1.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE X-Spam-Check-By: sourceware.org Received: from mailrelay005.isp.belgacom.be (HELO mailrelay005.isp.belgacom.be) (195.238.6.171) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 07 Mar 2012 20:41:00 +0000 X-Belgacom-Dynamic: yes X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ApMBAEbHV09R9oZK/2dsb2JhbAAMOIU0swIBAQEDASNWECUCJgICVwaIFqdHkiWBL44qgRYEpViCZA Received: from 74.134-246-81.adsl-dyn.isp.belgacom.be (HELO [192.168.1.3]) ([81.246.134.74]) by relay.skynet.be with ESMTP; 07 Mar 2012 21:40:58 +0100 Subject: Documenting E. packet. (was Re: [patch] Fix PR 13392 : check offset of JMP insn) From: Philippe Waroquiers To: Stan Shebs Cc: gdb-patches@sourceware.org In-Reply-To: <4F568602.8040005@earthlink.net> References: <4F561363.4070702@codesourcery.com> <4F56434F.4030107@redhat.com> <1331064879.2209.11.camel@soleil> <4F568602.8040005@earthlink.net> Content-Type: text/plain; charset="UTF-8" Date: Wed, 07 Mar 2012 20:41:00 -0000 Message-ID: <1331152865.2209.46.camel@soleil> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2012-03/txt/msg00247.txt.bz2 On Tue, 2012-03-06 at 13:47 -0800, Stan Shebs wrote: > > Is there somewhere a description of what an E. packet is, > > and when this is allowed ? > > ... > It doesn't look like it's officially described in the manual. The ... > > It's conceivable that one could do something with GDB that interprets > the error reply (whether NN or a string) and does something differently, > but in practice, if the target side is reporting errors, things are > going straight downhill and the user needs to decide what to do about > it. Also, if a particular result is common enough that GDB has code to > cope with it, then maybe it's just another element of the protocol, not > really an error. :-) Effectively, having GDB trying to do something sophisticated depending on the E NN nr or E. string received from the stub looks difficult. There is however already some kind of logic in GDB. E.g. in remote.c, the function trace_error handles differently E., E1? and E2?. There are other places where only E NN is considered as an error. E. is not considered as an error. Example: qRcmd. When I did the Valgrind gdbserver, I had to return a readable error msg to the user but did not find a way to do that in the doc. I found the E. by reading the gdb sources and used it (believing I was doing a nasty thing. But now, I see it is just an officially accepted error packet, just not documented :). => it looks better to document this E. packet. However, it is not clear to me what is exactly expected for this documentation/behaviour. It looks better if at all places where an E NN is accepted by GDB, GDB would also accept an E. packet. But that is not the current behaviour, so either remote.c is changed to consistently accept E NN and E. everywhere, or the protocol doc must match the current behaviour, and indicate for each packet if an E NN and/or an E. error is accepted. Philippe