qmp: Drop duplicated QMP command object checks

qmp_check_input_obj() duplicates qmp_dispatch_check_obj(), except the
latter screws up an error message.  handle_qmp_command() runs first
the former, then the latter via qmp_dispatch(), masking the screwup.

qemu-ga also masks the screwup, because it also duplicates checks,
just differently.

qmp_check_input_obj() exists because handle_qmp_command() needs to
examine the command before dispatching it.  The previous commit got
rid of this need, except for a tracepoint, and a bit of "id" code that
relies on qdict not being null.

Fix up the error message in qmp_dispatch_check_obj(), drop
qmp_check_input_obj() and the tracepoint.  Protect the "id" code with
a conditional.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1488544368-30622-9-git-send-email-armbru@redhat.com>

3 files changed, 7 insertions, 71 deletions

diff --git a/monitor.c b/monitor.c
index 0c06dc7703..ec7623efdd 100644
--- a/monitor.c
+++ b/monitor.c
@@ -3700,67 +3700,10 @@ static int monitor_can_read(void *opaque)
     return (mon->suspend_cnt == 0) ? 1 : 0;
 }
 
-/*
- * Input object checking rules
- *
- * 1. Input object must be a dict
- * 2. The "execute" key must exist
- * 3. The "execute" key must be a string
- * 4. If the "arguments" key exists, it must be a dict
- * 5. If the "id" key exists, it can be anything (ie. json-value)
- * 6. Any argument not listed above is considered invalid
- */
-static QDict *qmp_check_input_obj(QObject *input_obj, Error **errp)
-{
-    const QDictEntry *ent;
-    int has_exec_key = 0;
-    QDict *input_dict;
-
-    input_dict = qobject_to_qdict(input_obj);
-    if (!input_dict) {
-        error_setg(errp, QERR_QMP_BAD_INPUT_OBJECT, "object");
-        return NULL;
-    }
-
-
-    for (ent = qdict_first(input_dict); ent; ent = qdict_next(input_dict, ent)){
-        const char *arg_name = qdict_entry_key(ent);
-        const QObject *arg_obj = qdict_entry_value(ent);
-
-        if (!strcmp(arg_name, "execute")) {
-            if (qobject_type(arg_obj) != QTYPE_QSTRING) {
-                error_setg(errp, QERR_QMP_BAD_INPUT_OBJECT_MEMBER,
-                           "execute", "string");
-                return NULL;
-            }
-            has_exec_key = 1;
-        } else if (!strcmp(arg_name, "arguments")) {
-            if (qobject_type(arg_obj) != QTYPE_QDICT) {
-                error_setg(errp, QERR_QMP_BAD_INPUT_OBJECT_MEMBER,
-                           "arguments", "object");
-                return NULL;
-            }
-        } else if (!strcmp(arg_name, "id")) {
-            /* Any string is acceptable as "id", so nothing to check */
-        } else {
-            error_setg(errp, QERR_QMP_EXTRA_MEMBER, arg_name);
-            return NULL;
-        }
-    }
-
-    if (!has_exec_key) {
-        error_setg(errp, QERR_QMP_BAD_INPUT_OBJECT, "execute");
-        return NULL;
-    }
-
-    return input_dict;
-}
-
 static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens)
 {
     QObject *req, *rsp = NULL, *id = NULL;
     QDict *qdict = NULL;
-    const char *cmd_name;
     Monitor *mon = cur_mon;
     Error *err = NULL;
 
@@ -3773,17 +3716,12 @@ static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens)
         goto err_out;
     }
 
-    qdict = qmp_check_input_obj(req, &err);
-    if (!qdict) {
-        goto err_out;
-    }
-
-    id = qdict_get(qdict, "id");
-    qobject_incref(id);
-    qdict_del(qdict, "id");
-
-    cmd_name = qdict_get_str(qdict, "execute");
-    trace_handle_qmp_command(mon, cmd_name);
+    qdict = qobject_to_qdict(req);
+    if (qdict) {
+        id = qdict_get(qdict, "id");
+        qobject_incref(id);
+        qdict_del(qdict, "id");
+    } /* else will fail qmp_dispatch() */
 
     rsp = qmp_dispatch(cur_mon->qmp.commands, req);
 
diff --git a/qapi/qmp-dispatch.c b/qapi/qmp-dispatch.c
index 72827a30ba..7fb8aefe10 100644
--- a/qapi/qmp-dispatch.c
+++ b/qapi/qmp-dispatch.c
@@ -30,8 +30,7 @@ static QDict *qmp_dispatch_check_obj(const QObject *request, Error **errp)
 
     dict = qobject_to_qdict(request);
     if (!dict) {
-        error_setg(errp, QERR_QMP_BAD_INPUT_OBJECT,
-                   "request is not a dictionary");
+        error_setg(errp, QERR_QMP_BAD_INPUT_OBJECT, "object");
         return NULL;
     }
 
diff --git a/trace-events b/trace-events
index 728855743c..b07a09ba95 100644
--- a/trace-events
+++ b/trace-events
@@ -65,7 +65,6 @@ xen_remap_bucket(uint64_t index) "index %#"PRIx64
 xen_map_cache_return(void* ptr) "%p"
 
 # monitor.c
-handle_qmp_command(void *mon, const char *cmd_name) "mon %p cmd_name \"%s\""
 monitor_protocol_event_handler(uint32_t event, void *qdict) "event=%d data=%p"
 monitor_protocol_event_emit(uint32_t event, void *data) "event=%d data=%p"
 monitor_protocol_event_queue(uint32_t event, void *qdict, uint64_t rate) "event=%d data=%p rate=%" PRId64