On 02/23/2017 03:45 PM, Markus Armbruster wrote: > To enforce capability negotiation before normal operation, > handle_qmp_command() inspects every command before it's handed off to > qmp_dispatch(). This is a bit of a layering violation, and results in > duplicated code. > > Before capability negotiation (!cur_mon->in_command_mode), we fail > commands other than "qmp_capabilities". This is what enforces > capability negotiation. > > Afterwards, we fail command "qmp_capabilities". > > Clean this up as follows. > > The obvious place to fail a command is the command itself, so move the > "afterwards" check to qmp_qmp_capabilities(). > > We do the "before" check in every other command, but that would be > bothersome. Instead, start without all the other commands, by > registering only qmp_qmp_capabilities(). Register the others in > qmp_qmp_capabilities(). > > Additionally, replace the generic human-readable error message for > CommandNotFound by one that reminds the user to run qmp_capabilities. > Without that, we'd regress commit 2d5a834. > > Signed-off-by: Markus Armbruster <arm...@redhat.com> > --- > monitor.c | 70 > ++++++++++++++++++++++++++++++++++++--------------------------- > 1 file changed, 40 insertions(+), 30 deletions(-) >
> @@ -3781,12 +3782,21 @@ static void handle_qmp_command(JSONMessageParser
> *parser, GQueue *tokens)
> cmd_name = qdict_get_str(qdict, "execute");
> trace_handle_qmp_command(mon, cmd_name);
>
> - if (invalid_qmp_mode(mon, cmd_name, &err)) {
> - goto err_out;
> - }
> -
> rsp = qmp_dispatch(req);
>
> + qdict = qdict_get_qdict(qobject_to_qdict(rsp), "error");
> + if (qdict) {
> + if (!mon->qmp.in_command_mode
> + && !strcmp(qdict_get_try_str(qdict, "class"),
Ouch - this can call strcmp(NULL, ...) if the error is ill-formed. Is
that a problem? Can we assert that "class" will always exist as a string?
> +
> QapiErrorClass_lookup[ERROR_CLASS_COMMAND_NOT_FOUND])) {
> + /* Provide a more useful error message */
> + qdict_del(qdict, "desc");
> + qdict_put(qdict, "desc",
> + qstring_from_str("Expecting capabilities negotiation"
> + " with 'qmp_capabilities'"));
> + }
> + }
> +
Otherwise, I like it.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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