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Tue, 23 Jun 2020 16:05:11 +0000 (UTC) Date: Tue, 23 Jun 2020 17:05:08 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Eric Auger Subject: Re: [PATCH] qom: Allow object_property_add_child() to fail Message-ID: <20200623160508.GK751477@redhat.com> References: <20200623155452.30954-1-eric.auger@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200623155452.30954-1-eric.auger@redhat.com> User-Agent: Mutt/1.14.0 (2020-05-02) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Disposition: inline Received-SPF: pass client-ip=205.139.110.61; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/23 01:55:08 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: pbonzini@redhat.com, armbru@redhat.com, qemu-devel@nongnu.org, ehabkost@redhat.com, eric.auger.pro@gmail.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Jun 23, 2020 at 05:54:52PM +0200, Eric Auger wrote: > object_property_add() does not allow object_property_try_add() > to gracefully fail as &error_abort is passed as an error handle. > > However such failure can easily be triggered from the QMP shell when, > for instance, one attempts to create an object with an id that already > exists: > > For instance, call twice: > object-add qom-type=memory-backend-ram id=mem1 props.size=1073741824 > and QEMU aborts. > > This behavior is undesired as a user/management application mistake > in reusing a property ID shouldn't result in loss of the VM and live > data within. > > This patch introduces two new functions, object_property_add_err() and > object_property_add_child_err() whose prototype features an error handle. > object_property_add_child_err() now gets called from user_creatable_add_type. > This solution was chosen instead of changing the prototype of existing > functions because the number of existing callers is huge. > > The error now is returned gracefully to the QMP client. > > (QEMU) object-add qom-type=memory-backend-ram id=mem2 props.size=4294967296 > {"return": {}} > (QEMU) object-add qom-type=memory-backend-ram id=mem2 props.size=4294967296 > {"error": {"class": "GenericError", "desc": "attempt to add duplicate property > 'mem2' to object (type 'container')"}} > > Signed-off-by: Eric Auger > --- > include/qom/object.h | 24 ++++++++++++++++++++++-- > qom/object.c | 33 ++++++++++++++++++++++++++++----- > qom/object_interfaces.c | 7 +++++-- > 3 files changed, 55 insertions(+), 9 deletions(-) Reviewed-by: Daniel P. Berrangé Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|