From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 123816 invoked by alias); 12 Mar 2015 00:40:25 -0000 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 Received: (qmail 123788 invoked by uid 89); 12 Mar 2015 00:40:24 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.3 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.2 X-Spam-User: qpsmtpd, 2 recipients X-HELO: homiemail-a79.g.dreamhost.com Received: from sub5.mail.dreamhost.com (HELO homiemail-a79.g.dreamhost.com) (208.113.200.129) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 12 Mar 2015 00:40:22 +0000 Received: from homiemail-a79.g.dreamhost.com (localhost [127.0.0.1]) by homiemail-a79.g.dreamhost.com (Postfix) with ESMTP id 7390A7D4074; Wed, 11 Mar 2015 17:40:21 -0700 (PDT) Received: from redwood.eagercon.com (c-24-7-16-38.hsd1.ca.comcast.net [24.7.16.38]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: eager@eagerm.com) by homiemail-a79.g.dreamhost.com (Postfix) with ESMTPSA id 575087D406E; Wed, 11 Mar 2015 17:40:21 -0700 (PDT) Message-ID: <5500E074.6070002@eagerm.com> Date: Thu, 12 Mar 2015 00:40:00 -0000 From: Michael Eager User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Jan Kratochvil CC: "gdb-patches@sourceware.org" , binutils Subject: Re: [PATCH] Support gzip compressed exec and core files in gdb References: <54FF77D6.7010400@eagerm.com> <20150311221329.GB11980@host1.jankratochvil.net> In-Reply-To: <20150311221329.GB11980@host1.jankratochvil.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2015-03/txt/msg00330.txt.bz2 On 03/11/15 15:13, Jan Kratochvil wrote: > On Wed, 11 Mar 2015 00:01:42 +0100, Michael Eager wrote: >> Add support to automatically unzip compressed executable and core files. >> Files will be uncompressed into temporary directory (/tmp or $TMPDIR) >> and are deleted when GDB exits. > > Such feature has been requested to support xz-compressed core files as > currently being stored by systemd. But to make it more convenient one should > decompress on-demand only the blocks of file that are really accessed by GDB > - expecting by bfd_iovec. Obviously GDB usually needs to access only small > part of the whole core file. > > I did not check how it is supported by gzip but for xz one needs to use > --block-size, otherwise the file blocks cannot be decompressed independently > in random access way. gzip is not compressed block-by-block. As far as I can tell, you need to decompress starting from the beginning of the file. > ISTM libz-gzip and liblzma-xz compatibility is mutually exclusive. I don't know why they would be incompatible, but support for an on-demand block-compression scheme would be significantly different. Decompressing an xz file by making a copy (as is done for gzip) would be a simple extension to the current patch. -- Michael Eager eager@eagercon.com 1960 Park Blvd., Palo Alto, CA 94306 650-325-8077