From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id Ru/WK98tXmDrSgAAWB0awg (envelope-from ) for ; Fri, 26 Mar 2021 14:54:23 -0400 Received: by simark.ca (Postfix, from userid 112) id A79CF1EF7C; Fri, 26 Mar 2021 14:54:23 -0400 (EDT) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-0.7 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,RDNS_DYNAMIC,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (ip-8-43-85-97.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id E6BD71E789 for ; Fri, 26 Mar 2021 14:54:22 -0400 (EDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 959D73858C27; Fri, 26 Mar 2021 18:54:22 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 959D73858C27 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1616784862; bh=X/yFIw4eH0fUeAqEtn+4lyZRkyTOKh42ZhdUpBbJgmc=; h=Subject:To:References:Date:In-Reply-To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=eEIDq8xVzIkiH7NfNhfisKJdIeTWJKUBLlxCAzcFl587KFHFTfpHt5703nnrVcBLQ uWyHfveUH2Bf4dFR/RFnxcCKRcDIUcdJd1xiW1mvTzXVFa/hyfEX4/4Wv+ABT5i71m Dhbukn5IMVYpQB5rBsSw2a2GheQrXbzIcvnepDBA= Received: from smtp.polymtl.ca (smtp.polymtl.ca [132.207.4.11]) by sourceware.org (Postfix) with ESMTPS id 9C2733858C27 for ; Fri, 26 Mar 2021 18:54:19 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 9C2733858C27 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 12QIrC7p018596 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 26 Mar 2021 14:53:17 -0400 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp.polymtl.ca 12QIrC7p018596 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 CD5891E789; Fri, 26 Mar 2021 14:53:12 -0400 (EDT) Subject: Re: [PATCH v2] [PR gdb/27614] gdb-add-index fails on symlinks. To: Lancelot SIX , gdb-patches@sourceware.org References: <20210326171100.1491-1-lsix@lancelotsix.com> Message-ID: <1b31f1e8-9379-d6f7-afb6-40a6ce7fb379@polymtl.ca> Date: Fri, 26 Mar 2021 14:53:12 -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: <20210326171100.1491-1-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 Fri, 26 Mar 2021 18:53:12 +0000 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: , From: Simon Marchi via Gdb-patches Reply-To: Simon Marchi Errors-To: gdb-patches-bounces@sourceware.org Sender: "Gdb-patches" On 2021-03-26 1:11 p.m., Lancelot SIX via Gdb-patches wrote: > 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). > > To fix this, this commit proposes to use 'readlink' when available. This > command is not part of the standard POSIX tools, so this fix might not > work in all situations. It will at least provide an error message to > the user. > > There are no straightforward solution to go around the problem. The > .gdb-index, .debug_names and .debug_str files could be generated and > then identified by matching *.gdb-index, *.debug_names or *.debug_str. > This would be problematic if other files where to match this pattern. > Generating those index files in a dedicated directory raise the problem > of generating a unique dirname, and mkdtemp is not a standard POSIX > command so we cannot rely on it either. It could also be possible to > use something like "gdb --batch -nx -iex 'set auto-load no' -iex 'file > $file' -iex 'maint info bfds" and parse its output, but I am not sure > how future-proof this is. > > Long story short, I went for the simple option that fixes the reported > issue most of the time instead of trying to come with something > too complicated for limited added-value. I can change that if > required. > > gdb/ChangeLog: > > PR gdb/27614 > * contrib/gdb-add-index.sh: Fix when called with a symlink as an > argument. > > gdb/testsuite/ChangeLog: > > PR gdb/27614 > * gdb.dwarf2/gdb-add-index-symlink.exp: New test. > --- > gdb/contrib/gdb-add-index.sh | 15 +++++- > .../gdb.dwarf2/gdb-add-index-symlink.exp | 47 +++++++++++++++++++ > 2 files changed, 61 insertions(+), 1 deletion(-) > create mode 100644 gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp > > diff --git a/gdb/contrib/gdb-add-index.sh b/gdb/contrib/gdb-add-index.sh > index 60287b97fba..48a85136a4c 100755 > --- a/gdb/contrib/gdb-add-index.sh > +++ b/gdb/contrib/gdb-add-index.sh > @@ -35,7 +35,20 @@ if test $# != 1; then > exit 1 > fi > > -file="$1" > +if test -L "$1"; then > + # This script will most likely fail if the argument is a symlink to a > + # program. In order to avoid that, try to follow the symlink. However, > + # readlink is not a standard POSIX tool so we have to check if it is > + # available. > + if command -v readlink >/dev/null 2>&1; then > + file="$(readlink -e "$1")" BSDs' readlink doesn't have the -e option, so it would probably derail from here (should we also check the exit status of readlink to make sure it worked? did you try with a symlink pointing to a non-existent file / with a non-existent component?). Would it work with just `readlink `? Simon