qmp: support out-of-band (oob) execution

Having "allow-oob":true for a command does not mean that this command
will always be run in out-of-band mode.  The out-of-band quick path will
only be executed if we specify the extra "run-oob" flag when sending the
QMP request:

    { "execute":   "command-that-allows-oob",
      "arguments": { ... },
      "control":   { "run-oob": true } }

The "control" key is introduced to store this extra flag.  "control"
field is used to store arguments that are shared by all the commands,
rather than command specific arguments.  Let "run-oob" be the first.

Note that in the patch I exported qmp_dispatch_check_obj() to be used to
check the request earlier, and at the same time allowed "id" field to be
there since actually we always allow that.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180309090006.10018-19-peterx@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: rebase to qobject_to(), spelling fix]
Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/qapi/qmp/dispatch.h b/include/qapi/qmp/dispatch.h
index 26eb13ff41..ffb4652f71 100644
--- a/include/qapi/qmp/dispatch.h
+++ b/include/qapi/qmp/dispatch.h
@@ -48,6 +48,8 @@ bool qmp_command_is_enabled(const QmpCommand *cmd);
 const char *qmp_command_name(const QmpCommand *cmd);
 bool qmp_has_success_response(const QmpCommand *cmd);
 QObject *qmp_build_error_object(Error *err);
+QDict *qmp_dispatch_check_obj(const QObject *request, Error **errp);
+bool qmp_is_oob(QDict *dict);
 
 typedef void (*qmp_cmd_callback_fn)(QmpCommand *cmd, void *opaque);