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Tue, 14 Apr 2020 09:42:24 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-113-20.ams2.redhat.com [10.36.113.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 31A639F999; Tue, 14 Apr 2020 09:42:24 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id AB69711385C8; Tue, 14 Apr 2020 11:42:22 +0200 (CEST) From: Markus Armbruster To: Eric Blake Subject: Re: [PATCH for-5.1 2/8] qemu-options: Factor out get_opt_name_value() helper References: <20200409153041.17576-1-armbru@redhat.com> <20200409153041.17576-3-armbru@redhat.com> <5f39e636-f799-55f3-873f-08a3a0f53dca@redhat.com> Date: Tue, 14 Apr 2020 11:42:22 +0200 In-Reply-To: <5f39e636-f799-55f3-873f-08a3a0f53dca@redhat.com> (Eric Blake's message of "Thu, 9 Apr 2020 13:01:59 -0500") Message-ID: <87blnuwght.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] 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: kwolf@redhat.com, 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" Eric Blake writes: > On 4/9/20 10:30 AM, Markus Armbruster wrote: >> The next commits will put it to use. >> >> Signed-off-by: Markus Armbruster >> --- >> util/qemu-option.c | 102 +++++++++++++++++++++++++-------------------- >> 1 file changed, 56 insertions(+), 46 deletions(-) >> > >> +static const char *get_opt_name_value(const char *params, >> + const char *firstname, >> + char **name, char **value) >> +{ >> + const char *p, *pe, *pc; >> + >> + pe =3D strchr(params, '=3D'); >> + pc =3D strchr(params, ','); >> + >> + if (!pe || (pc && pc < pe)) { >> + /* found "foo,more" */ >> + if (firstname) { >> + /* implicitly named first option */ >> + *name =3D g_strdup(firstname); >> + p =3D get_opt_value(params, value); > > Is this correct even when params is "foo,,more"? But... > >> static void opts_do_parse(QemuOpts *opts, const char *params, >> const char *firstname, bool prepend, >> bool *invalidp, Error **errp) >> { >> - char *option =3D NULL; >> - char *value =3D NULL; >> - const char *p,*pe,*pc; >> Error *local_err =3D NULL; >> + char *option, *value; >> + const char *p; >> - for (p =3D params; *p !=3D '\0'; p++) { >> - pe =3D strchr(p, '=3D'); >> - pc =3D strchr(p, ','); >> - if (!pe || (pc && pc < pe)) { >> - /* found "foo,more" */ >> - if (p =3D=3D params && firstname) { >> - /* implicitly named first option */ >> - option =3D g_strdup(firstname); >> - p =3D get_opt_value(p, &value); > > ...in this patch, it is just code motion, so if it is a bug, it's > pre-existing and worth a separate fix. If @p points to "foo,,more", possibly followed by additional characters, then we have pc && pc < pe, and enter this conditional. This means that foo,,more=3D42 gets parsed as two name=3Dvalue, either as name value ----------------------- @firstname "foo,more" "" "42" if @firstname is non-null, or else as name value ----------------- "foo,,more" "on" "" "42" Has always been that way; see commit e27c88fe9e "QemuOpts: framework for storing and parsing options.", v0.12.0. You might expect name value ----------------- "foo,,more" "42" or name value ----------------- "foo,more" "42" instead. Close, but no cigar. A language without syntax errors is bound to surprise. > Reviewed-by: Eric Blake Thanks!