qapi: introduce new cmd option "allow-oob"

Here "oob" stands for "Out-Of-Band".  When "allow-oob" is set, it means
the command allows out-of-band execution.

The "oob" idea is proposed by Markus Armbruster in following thread:

  https://lists.gnu.org/archive/html/qemu-devel/2017-09/msg02057.html

This new "allow-oob" boolean will be exposed by "query-qmp-schema" as
well for command entries, so that QMP clients can know which commands
can be used in out-of-band calls. For example the command "migrate"
originally looks like:

  {"name": "migrate", "ret-type": "17", "meta-type": "command",
   "arg-type": "86"}

And it'll be changed into:

  {"name": "migrate", "ret-type": "17", "allow-oob": false,
   "meta-type": "command", "arg-type": "86"}

This patch only provides the QMP interface level changes.  It does not
contain the real out-of-band execution implementation yet.

Suggested-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180309090006.10018-18-peterx@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: rebase on introspection done by qlit]
Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 13 insertions, 5 deletions

diff --git a/scripts/qapi/commands.py b/scripts/qapi/commands.py
index 21a7e0dbe6..0c5da3a54d 100644
--- a/scripts/qapi/commands.py
+++ b/scripts/qapi/commands.py
@@ -193,10 +193,18 @@ out:
     return ret
 
 
-def gen_register_command(name, success_response):
-    options = 'QCO_NO_OPTIONS'
+def gen_register_command(name, success_response, allow_oob):
+    options = []
+
     if not success_response:
-        options = 'QCO_NO_SUCCESS_RESP'
+        options += ['QCO_NO_SUCCESS_RESP']
+    if allow_oob:
+        options += ['QCO_ALLOW_OOB']
+
+    if not options:
+        options = ['QCO_NO_OPTIONS']
+
+    options = " | ".join(options)
 
     ret = mcgen('''
     qmp_register_command(cmds, "%(name)s",
@@ -268,7 +276,7 @@ void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds);
         genc.add(gen_registry(self._regy, self._prefix))
 
     def visit_command(self, name, info, arg_type, ret_type,
-                      gen, success_response, boxed):
+                      gen, success_response, boxed, allow_oob):
         if not gen:
             return
         self._genh.add(gen_command_decl(name, arg_type, boxed, ret_type))
@@ -277,7 +285,7 @@ void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds);
             self._genc.add(gen_marshal_output(ret_type))
         self._genh.add(gen_marshal_decl(name))
         self._genc.add(gen_marshal(name, arg_type, boxed, ret_type))
-        self._regy += gen_register_command(name, success_response)
+        self._regy += gen_register_command(name, success_response, allow_oob)
 
 
 def gen_commands(schema, output_dir, prefix):