[Qemu-devel] [PATCH 12/13] QMP: Introduce qmp_check_input_obj()

[Luiz Capitulino <lcapitulino@redhat.com>]

This is similar to qmp_check_client_args(), but it checks if
the input object follows the specification (QMP/qmp-spec.txt
section 2.3).

As we're limited to three keys, the work here is quite simple:
we iterate over the input object, checking each time if the
current argument complies to the specification.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
---
 monitor.c |   45 +++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 45 insertions(+), 0 deletions(-)

diff --git a/monitor.c b/monitor.c
index 2a29095..a24a152 100644
--- a/monitor.c
+++ b/monitor.c
@@ -4163,6 +4163,46 @@ out:
     return err;
 }
 
+/*
+ * Input object checking rules
+ *
+ * 1. "execute" key must exist (not checked here)
+ * 2. "execute" key must be a string
+ * 3. "arguments" key must be a dict
+ * 4. "id" key can be anything (ie. json-value)
+ * 5. Any argument not listed above is considered unexpected
+ */
+static int qmp_check_input_obj(const QDict *input_obj)
+{
+    const QDictEntry *ent;
+
+    for (ent = qdict_first(input_obj); ent; ent = qdict_next(input_obj, 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) {
+                qerror_report(QERR_QMP_BAD_INPUT_OBJECT_MEMBER, "execute",
+                              "string");
+                return -1;
+            }
+        } else if (!strcmp(arg_name, "arguments")) {
+            if (qobject_type(arg_obj) != QTYPE_QDICT) {
+                qerror_report(QERR_QMP_BAD_INPUT_OBJECT_MEMBER, "arguments",
+                              "object");
+                return -1;
+            }
+        } else if (!strcmp(arg_name, "id")) {
+            /* FIXME: check duplicated IDs for async commands */
+        } else {
+            qerror_report(QERR_QMP_UNEXPECTED_INPUT_OBJECT_MEMBER, arg_name);
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
 static void handle_qmp_command(JSONMessageParser *parser, QList *tokens)
 {
     int err;
@@ -4187,6 +4227,11 @@ static void handle_qmp_command(JSONMessageParser *parser, QList *tokens)
 
     input = qobject_to_qdict(obj);
 
+    err = qmp_check_input_obj(input);
+    if (err < 0) {
+        goto err_input;
+    }
+
     mon->mc->id = qdict_get(input, "id");
     qobject_incref(mon->mc->id);
 
-- 
1.7.1.359.gd0b8d