From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.polymtl.ca (smtp.polymtl.ca [132.207.4.11]) by sourceware.org (Postfix) with ESMTPS id 44944385703C for ; Sun, 28 Mar 2021 16:12:31 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 44944385703C Received: from simark.ca (simark.ca [158.69.221.121]) (authenticated bits=0) by smtp.polymtl.ca (8.14.7/8.14.7) with ESMTP id 12SGBMO6030161 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 28 Mar 2021 12:11:28 -0400 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp.polymtl.ca 12SGBMO6030161 Received: from [10.0.0.11] (192-222-157-6.qc.cable.ebox.net [192.222.157.6]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by simark.ca (Postfix) with ESMTPSA id B8EF51E01F; Sun, 28 Mar 2021 12:11:22 -0400 (EDT) Subject: Re: [PATCH v3] [PR gdb/27614] gdb-add-index fails on symlinks. To: Lancelot SIX , gdb-patches@sourceware.org References: <20210327172758.30356-1-lsix@lancelotsix.com> From: Simon Marchi Message-ID: <981b48ee-133a-7f06-9e5d-d1c331f360d1@polymtl.ca> Date: Sun, 28 Mar 2021 12:11:22 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210327172758.30356-1-lsix@lancelotsix.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Poly-FromMTA: (simark.ca [158.69.221.121]) at Sun, 28 Mar 2021 16:11:23 +0000 X-Spam-Status: No, score=-4.3 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_PASS, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 28 Mar 2021 16:12:32 -0000 On 2021-03-27 1:27 p.m., Lancelot SIX via Gdb-patches wrote: > Since V2: > - Use GDB to follow symlink instead of readlink. Unlike > readlink, GDB is guaranteed to be available. > > Since V1: > - Replace '&>/dev/null' with '>/dev/null 2>&1' > > -- > > PR 27614 shows that gdb-add-index fails to generate the index when its > argument is a symlink. > > The following one liner illustrates the reported problem: > > $ echo 'int main(){}'|gcc -g -x c -;ln -s a.out symlink;gdb-add-index symlink > gdb-add-index: No index was created for symlink > gdb-add-index: [Was there no debuginfo? Was there already an index?] > $ ls -l > -rwxr-xr-x 1 25712 Mar 19 23:05 a.out* > -rw------- 1 8277 Mar 19 23:05 a.out.gdb-index > lrwxrwxrwx 1 5 Mar 19 23:05 symlink -> a.out* > > GDB generates the .gdb-index file with a name that matches the name of > the actual program (a.out.gdb-index here), not the symlink that > references it. The remaining of the script is looking for a file named > after the provided argument (would be 'symlink.gdb-index' in our > example). > > The common option to solve such issue would be to use readlink to follow > the symlink. Unfortunately, this command is not available in the POSIX > standard. This commit therefore proposes to use GDB itself to identify > where the symlink points to. This requires some parsing of GDB output. > The added test should be enough to detect regression if GDB where to > change the way it formats its output. I preferred your previous approach, compared to relying on a maintenance command. Relying on a maintenance command is fine in tests, for example, but here somebody could use gdb-add-index from a given GDB version with a GDB of a different version. GDB=/my/newer/gdb gdb-add-index a.out In the previous review, you said: >> Would it work with just `readlink `? > This would fail if $file is a symlink to a symlink. This is what > ldconfig usually does (libfoo.so -> libfoo.so.x -> libfoo.so.x.y). Can't you just call it in a loop then? while file is a symlink: file=readlink $file Simon