From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 109366 invoked by alias); 17 Feb 2016 14:40:59 -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 109354 invoked by uid 89); 17 Feb 2016 14:40:58 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=Hx-languages-length:2111 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Wed, 17 Feb 2016 14:40:57 +0000 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id 8FF95C00EB13; Wed, 17 Feb 2016 14:40:56 +0000 (UTC) Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u1HEes4D021272; Wed, 17 Feb 2016 09:40:55 -0500 Message-ID: <56C48676.8070404@redhat.com> Date: Wed, 17 Feb 2016 14:40:00 -0000 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Gary Benson CC: Luis Machado , gdb-patches@sourceware.org Subject: Re: [PATCH] Remote debugging without a binary (regression) References: <1455200365-5270-1-git-send-email-lgustavo@codesourcery.com> <20160211163510.GA21352@blade.nx> <56BCBF8F.8040601@codesourcery.com> <20160212103144.GB12352@blade.nx> <56BDF92B.50107@redhat.com> <20160217135324.GC24631@blade.nx> In-Reply-To: <20160217135324.GC24631@blade.nx> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-SW-Source: 2016-02/txt/msg00511.txt.bz2 On 02/17/2016 01:53 PM, Gary Benson wrote: > Pedro Alves wrote: >> On 02/12/2016 10:31 AM, Gary Benson wrote: >>> FWIW I tried this (both on the same machine): >>> >>> gdbserver :9999 /bin/ls >>> gdb -q -ex "set sysroot /whatever" -ex "target remote :9999" >>> >>> and got this: >>> >>> Reading symbols from /bin/ls...(no debugging symbols found)...done. >>> >>> which I think is an error: the sysroot is being ignored. >> >> I agree. If you tell gdb about a sysroot, then I can't think why >> you'd want it to try opening an absolute filename on the host, >> outside the sysroot. >> >> (caching and buildid matching aside) > > There isn't any caching or buildid matching, the logic in > exec_file_locate_attach is wrong. Yes, what I meant was -- a valid reason I'd see gdb trying to open a file on the host outside the sysroot would be for smarter buildid matching and local caching of (hunks of) files. But we don't have that. > It might even be the cause > of the exception Luis is seeing so with luck we can avoid a > try-catch in remote_add_inferior. I'm putting together a patch > now. Yes, if GDB ends up not trying to open any file, then it'll mask off the exception Luis is seeing. However, even if the sysroot points at the location with a valid copy of the file, if the file is NOT readable, then we'll still throw and close the connection. Wait, actually, that's actually a good way to add a test to the testsuite to cover Luis's use case, even without separate filesystems: gdbserver: $ ./gdbserver/gdbserver :9999 ~/gdb/tests/threads& $ chmod 000 ~/gdb/tests/threads gdb: (gdb) tar remote :9999 Remote debugging using :9999 Reading /home/pedro/gdb/tests/threads from remote target... warning: File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead. "target:/home/pedro/gdb/tests/threads": could not open as an executable file: Permission denied. (gdb) maint print target-stack The current target stack is: - None (None) (gdb) Above we dropped the connection... Thanks, Pedro Alves