From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31DC8C2BA19 for ; Tue, 14 Apr 2020 17:04:20 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B0C9320678 for ; Tue, 14 Apr 2020 17:04:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Fv2EqRUJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B0C9320678 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35528 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jOOyu-0002Tm-Qr for qemu-devel@archiver.kernel.org; Tue, 14 Apr 2020 13:04:18 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:32838) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jOOjh-0003Xm-Oz for qemu-devel@nongnu.org; Tue, 14 Apr 2020 12:48:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jOOjd-0001Ql-RT for qemu-devel@nongnu.org; Tue, 14 Apr 2020 12:48:33 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:46355 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jONCe-0005VY-OT for qemu-devel@nongnu.org; Tue, 14 Apr 2020 11:10:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1586877020; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mHjDn7GVjkKmjZF0kyX6Ab2OXXDLE9a22KNo8L8ZMHw=; b=Fv2EqRUJs6HDDQd4NjZEDQz5pZgAvRE6RPd/M2yTnpNr/nWqK1MqrTDgiAWcX3WEW8hQCQ kdLU6H+4FrzPsCjAA3f/1sZ2m8604ri6MGpjJd8AopqgTQmzPopVhxDON5gXXb8iP7MIcT rDibYKYzu/PnaPAtukYt1MsN7MD1XaU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-287-zZlt4Md7NZmk3ug6P-SKmQ-1; Tue, 14 Apr 2020 11:10:18 -0400 X-MC-Unique: zZlt4Md7NZmk3ug6P-SKmQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9A7F613F8; Tue, 14 Apr 2020 15:10:17 +0000 (UTC) Received: from linux.fritz.box (ovpn-114-1.ams2.redhat.com [10.36.114.1]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 366C919C69; Tue, 14 Apr 2020 15:10:16 +0000 (UTC) Date: Tue, 14 Apr 2020 17:10:14 +0200 From: Kevin Wolf To: Markus Armbruster Subject: Re: [PATCH for-5.1 8/8] qemu-option: Move is_valid_option_list() to qemu-img.c and rewrite Message-ID: <20200414151014.GM7747@linux.fritz.box> References: <20200409153041.17576-1-armbru@redhat.com> <20200409153041.17576-9-armbru@redhat.com> <87k12ixxlb.fsf@dusky.pond.sub.org> <87blnup257.fsf@dusky.pond.sub.org> MIME-Version: 1.0 In-Reply-To: <87blnup257.fsf@dusky.pond.sub.org> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 14.04.2020 um 16:34 hat Markus Armbruster geschrieben: > Markus Armbruster writes: >=20 > > Eric Blake writes: > > > >> On 4/9/20 10:30 AM, Markus Armbruster wrote: > >>> is_valid_option_list()'s purpose is ensuring qemu-img.c's can safely > >>> join multiple parameter strings separated by ',' like this: > >>> > >>> g_strdup_printf("%s,%s", params1, params2); > >>> > >>> How it does that is anything but obvious. A close reading of the cod= e > >>> reveals that it fails exactly when its argument starts with ',' or > >>> ends with an odd number of ','. Makes sense, actually, because when > >>> the argument starts with ',', a separating ',' preceding it would get > >>> escaped, and when it ends with an odd number of ',', a separating ',' > >>> following it would get escaped. > >>> > >>> Move it to qemu-img.c and rewrite it the obvious way. > >>> > >>> Signed-off-by: Markus Armbruster > >>> --- > >>> include/qemu/option.h | 1 - > >>> qemu-img.c | 26 ++++++++++++++++++++++++++ > >>> util/qemu-option.c | 22 ---------------------- > >>> 3 files changed, 26 insertions(+), 23 deletions(-) > >>> > >> > >>> +++ b/qemu-img.c > >>> @@ -223,6 +223,32 @@ static bool qemu_img_object_print_help(const cha= r *type, QemuOpts *opts) > >>> return true; > >>> } > >>> +/* > >>> + * Is @optarg safe for accumulate_options()? > >>> + * It is when multiple of them can be joined together separated by '= ,'. > >>> + * To make that work, @optarg must not start with ',' (or else a > >>> + * separating ',' preceding it gets escaped), and it must not end wi= th > >>> + * an odd number of ',' (or else a separating ',' following it gets > >>> + * escaped). > >>> + */ > >>> +static bool is_valid_option_list(const char *optarg) > >>> +{ > >>> + size_t len =3D strlen(optarg); > >>> + size_t i; > >>> + > >>> + if (optarg[0] =3D=3D ',') { > >>> + return false; > >>> + } > >>> + > >>> + for (i =3D len; i > 0 && optarg[i - 1] =3D=3D ','; i--) { > >>> + } > >>> + if ((len - i) % 2) { > >>> + return false; > >>> + } > >>> + > >>> + return true; > >> > >> Okay, that's easy to read. Note that is_valid_option_list("") returns > >> true. > > > > Hmm, that's a bug: > > > > $ qemu-img create -f qcow2 -o backing_file=3Da -o "" -o backing_fmt= =3Draw,size=3D1M new.qcow2 > > qemu-img: warning: Could not verify backing image. This may become = an error in future versions. > > Could not open 'a,backing_fmt=3Draw': No such file or directory > > Formatting 'new.qcow2', fmt=3Dqcow2 size=3D1048576 backing_file=3Da= ,,backing_fmt=3Draw cluster_size=3D65536 lazy_refcounts=3Doff refcount_bits= =3D16 > > $ qemu-img info new.qcow2=20 > > image: new.qcow2 > > file format: qcow2 > > virtual size: 1 MiB (1048576 bytes) > > disk size: 196 KiB > > cluster_size: 65536 > > --> backing file: a,backing_fmt=3Draw > > Format specific information: > > compat: 1.1 > > lazy refcounts: false > > refcount bits: 16 > > corrupt: false > > > > My rewrite preserves this bug. Will fix in v2. >=20 > Kevin, two obvious fixes: >=20 > * Make is_valid_option_list() reject -o "" >=20 > * Make accumulate_options(options, "") return options. >=20 > Got a preference? In other words, the choice is between reporting an error and ignoring it silently. I think reporting an error makes more sense. Kevin