[Qemu-devel] [PATCH 12/12] RFC: qmp: rework 'id' handling

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

Let qmp_dispatch() copy the 'id' field. That way any qmp client will
conform to the specification, including QGA. Furthermore, it
simplifies the work for qemu monitor.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 monitor.c           | 31 ++++++++++++-------------------
 qapi/qmp-dispatch.c | 10 ++++++++--
 tests/test-qga.c    | 13 +++++--------
 3 files changed, 25 insertions(+), 29 deletions(-)

diff --git a/monitor.c b/monitor.c
index a3efe96d1d..bf192697e4 100644
--- a/monitor.c
+++ b/monitor.c
@@ -249,8 +249,6 @@ QEMUBH *qmp_dispatcher_bh;
 struct QMPRequest {
     /* Owner of the request */
     Monitor *mon;
-    /* "id" field of the request */
-    QObject *id;
     /*
      * Request object to be handled or Error to be reported
      * (exactly one of them is non-null)
@@ -351,7 +349,6 @@ int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
 
 static void qmp_request_free(QMPRequest *req)
 {
-    qobject_unref(req->id);
     qobject_unref(req->req);
     error_free(req->err);
     g_free(req);
@@ -3991,18 +3988,14 @@ static int monitor_can_read(void *opaque)
  * Null @rsp can only happen for commands with QCO_NO_SUCCESS_RESP.
  * Nothing is emitted then.
  */
-static void monitor_qmp_respond(Monitor *mon, QDict *rsp, QObject *id)
+static void monitor_qmp_respond(Monitor *mon, QDict *rsp)
 {
     if (rsp) {
-        if (id) {
-            qdict_put_obj(rsp, "id", qobject_ref(id));
-        }
-
         qmp_send_response(mon, rsp);
     }
 }
 
-static void monitor_qmp_dispatch(Monitor *mon, QObject *req, QObject *id)
+static void monitor_qmp_dispatch(Monitor *mon, QObject *req)
 {
     Monitor *old_mon;
     QDict *rsp;
@@ -4027,7 +4020,7 @@ static void monitor_qmp_dispatch(Monitor *mon, QObject *req, QObject *id)
         }
     }
 
-    monitor_qmp_respond(mon, rsp, id);
+    monitor_qmp_respond(mon, rsp);
     qobject_unref(rsp);
 }
 
@@ -4081,12 +4074,15 @@ static void monitor_qmp_bh_dispatcher(void *data)
 
     need_resume = !qmp_oob_enabled(req_obj->mon);
     if (req_obj->req) {
-        trace_monitor_qmp_cmd_in_band(qobject_get_try_str(req_obj->id) ?: "");
-        monitor_qmp_dispatch(req_obj->mon, req_obj->req, req_obj->id);
+        QDict *qdict = qobject_to(QDict, req_obj->req);
+        QObject *id = qdict ? qdict_get(qdict, "id") : NULL;
+        trace_monitor_qmp_cmd_in_band(qobject_get_try_str(id) ?: "");
+        monitor_qmp_dispatch(req_obj->mon, req_obj->req);
     } else {
         assert(req_obj->err);
         rsp = qmp_error_response(req_obj->err);
-        monitor_qmp_respond(req_obj->mon, rsp, NULL);
+        req_obj->err = NULL;
+        monitor_qmp_respond(req_obj->mon, rsp);
         qobject_unref(rsp);
     }
 
@@ -4115,8 +4111,7 @@ static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens)
 
     qdict = qobject_to(QDict, req);
     if (qdict) {
-        id = qobject_ref(qdict_get(qdict, "id"));
-        qdict_del(qdict, "id");
+        id = qdict_get(qdict, "id");
     } /* else will fail qmp_dispatch() */
 
     if (trace_event_get_state_backends(TRACE_HANDLE_QMP_COMMAND)) {
@@ -4127,15 +4122,13 @@ static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens)
 
     if (qdict && qmp_is_oob(qdict)) {
         /* OOB commands are executed immediately */
-        trace_monitor_qmp_cmd_out_of_band(qobject_get_try_str(id)
-                                          ?: "");
-        monitor_qmp_dispatch(mon, req, id);
+        trace_monitor_qmp_cmd_out_of_band(qobject_get_try_str(id) ?: "");
+        monitor_qmp_dispatch(mon, req);
         return;
     }
 
     req_obj = g_new0(QMPRequest, 1);
     req_obj->mon = mon;
-    req_obj->id = id;
     req_obj->req = req;
     req_obj->err = err;
 
diff --git a/qapi/qmp-dispatch.c b/qapi/qmp-dispatch.c
index 90ba5e3074..acea0fcfcd 100644
--- a/qapi/qmp-dispatch.c
+++ b/qapi/qmp-dispatch.c
@@ -59,6 +59,8 @@ static QDict *qmp_dispatch_check_obj(const QObject *request, bool allow_oob,
                            "QMP input member 'arguments' must be an object");
                 return NULL;
             }
+        } else if (!strcmp(arg_name, "id")) {
+            continue;
         } else {
             error_setg(errp, "QMP input member '%s' is unexpected",
                        arg_name);
@@ -166,8 +168,8 @@ QDict *qmp_dispatch(QmpCommandList *cmds, QObject *request,
                     bool allow_oob)
 {
     Error *err = NULL;
-    QObject *ret;
-    QDict *rsp;
+    QDict *rsp, *dict = qobject_to(QDict, request);
+    QObject *ret, *id = dict ? qdict_get(dict, "id") : NULL;
 
     ret = do_qmp_dispatch(cmds, request, allow_oob, &err);
 
@@ -181,5 +183,9 @@ QDict *qmp_dispatch(QmpCommandList *cmds, QObject *request,
         rsp = NULL;
     }
 
+    if (rsp && id) {
+        qdict_put_obj(rsp, "id", qobject_ref(id));
+    }
+
     return rsp;
 }
diff --git a/tests/test-qga.c b/tests/test-qga.c
index d638b1571a..4ee8b405f4 100644
--- a/tests/test-qga.c
+++ b/tests/test-qga.c
@@ -227,18 +227,15 @@ static void test_qga_ping(gconstpointer fix)
     qobject_unref(ret);
 }
 
-static void test_qga_invalid_id(gconstpointer fix)
+static void test_qga_id(gconstpointer fix)
 {
     const TestFixture *fixture = fix;
-    QDict *ret, *error;
-    const char *class;
+    QDict *ret;
 
     ret = qmp_fd(fixture->fd, "{'execute': 'guest-ping', 'id': 1}");
     g_assert_nonnull(ret);
-
-    error = qdict_get_qdict(ret, "error");
-    class = qdict_get_try_str(error, "class");
-    g_assert_cmpstr(class, ==, "GenericError");
+    qmp_assert_no_error(ret);
+    g_assert_cmpint(qdict_get_int(ret, "id"), ==, 1);
 
     qobject_unref(ret);
 }
@@ -1014,7 +1011,7 @@ int main(int argc, char **argv)
     g_test_add_data_func("/qga/file-ops", &fix, test_qga_file_ops);
     g_test_add_data_func("/qga/file-write-read", &fix, test_qga_file_write_read);
     g_test_add_data_func("/qga/get-time", &fix, test_qga_get_time);
-    g_test_add_data_func("/qga/invalid-id", &fix, test_qga_invalid_id);
+    g_test_add_data_func("/qga/id", &fix, test_qga_id);
     g_test_add_data_func("/qga/invalid-oob", &fix, test_qga_invalid_oob);
     g_test_add_data_func("/qga/invalid-cmd", &fix, test_qga_invalid_cmd);
     g_test_add_data_func("/qga/invalid-args", &fix, test_qga_invalid_args);
-- 
2.18.0.rc1