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Mon, 30 Mar 2020 07:18:12 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-112-69.ams2.redhat.com [10.36.112.69]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8E98019756; Mon, 30 Mar 2020 07:18:10 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 87B6F11385E2; Mon, 30 Mar 2020 09:18:08 +0200 (CEST) From: Markus Armbruster To: "Dr. David Alan Gilbert" Subject: Re: [PATCH v2] migration: use "" instead of (null) for tls-authz References: <0a9dc2fcb78da13eb326992384bc4e57de83d9f9.1584797648.git.maozhongyi@cmss.chinamobile.com> <20200324100823.GB2645@work-vm> Date: Mon, 30 Mar 2020 09:18:08 +0200 In-Reply-To: <20200324100823.GB2645@work-vm> (David Alan Gilbert's message of "Tue, 24 Mar 2020 10:08:23 +0000") Message-ID: <875zemz4y7.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 2.84 on 10.5.11.23 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] [fuzzy] X-Received-From: 216.205.24.74 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: berrange@redhat.com, qemu-devel@nongnu.org, Mao Zhongyi , quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" "Dr. David Alan Gilbert" writes: > * Mao Zhongyi (maozhongyi@cmss.chinamobile.com) wrote: >> run: >> (qemu) info migrate_parameters >> announce-initial: 50 ms >> ... >> announce-max: 550 ms >> multifd-compression: none >> xbzrle-cache-size: 4194304 >> max-postcopy-bandwidth: 0 >> tls-authz: '(null)' >>=20 >> Migration parameter 'tls-authz' is used to provide the QOM ID >> of a QAuthZ subclass instance that provides the access control >> check, default is NULL. But the empty string is not a valid >> object ID, so use "" instead of the default. Although it will >> fail when lookup an object with ID "", it is harmless, just >> consistent with tls_creds. > > Yes, it's probably the best we can do given Dan's explanation that > we can't change tls_authz to be non-null. As I explained in Message-ID: <878sjv11xm.fsf@dusky.pond.sub.org>, this is actually a crash bug on some systems. The commit message neglects to mention that. Too late to fix now. Next time :) >> Also fixed the bad indentation on the last line. >>=20 >> Signed-off-by: Mao Zhongyi >> --- >> migration/migration.c | 3 ++- >> monitor/hmp-cmds.c | 2 +- >> 2 files changed, 3 insertions(+), 2 deletions(-) >>=20 >> diff --git a/migration/migration.c b/migration/migration.c >> index c1d88ace7f..b060153ef7 100644 >> --- a/migration/migration.c >> +++ b/migration/migration.c >> @@ -790,7 +790,8 @@ MigrationParameters *qmp_query_migrate_parameters(Er= ror **errp) >> params->has_tls_hostname =3D true; >> params->tls_hostname =3D g_strdup(s->parameters.tls_hostname); >> params->has_tls_authz =3D true; >> - params->tls_authz =3D g_strdup(s->parameters.tls_authz); >> + params->tls_authz =3D s->parameters.tls_authz ? \ >> + g_strdup(s->parameters.tls_authz) : g_strdup(""= ); > > The \ is unneeded; this isn't a macro; it's also a little shorter to do > it as: > params->tls_authz =3D g_strdup(s->parameters.tls_authz ? > s->parameters.tls_authz : ""); Even shorter: params->tls_authz =3D g_strdup(s->parameters.tls_authz ?: ""); ?: is a GNU C extension. We use it all over the place. Just FYI. I'm *not* asking for the code to be changed.