[Qemu-devel] [PATCH 8/9] QMP: Introduce qmp_check_input_obj()

[Luiz Capitulino <lcapitulino@redhat.com>]

This is similar to qmp_check_client_args(), but 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, each time checking if the
given 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 1875731..654b193 100644
--- a/monitor.c
+++ b/monitor.c
@@ -4271,6 +4271,45 @@ static int qmp_check_client_args(const mon_cmd_t *cmd, QDict *client_args)
     return res.result;
 }
 
+/*
+ * 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 invalid
+ */
+static void qmp_check_input_obj(const char *input_obj_arg_name,
+                                QObject *input_obj_arg, void *opaque)
+{
+    int *err = opaque;
+
+    if (*err < 0) {
+        /* report only the first error */
+        return;
+    }
+
+    if (!strcmp(input_obj_arg_name, "execute")) {
+        if (qobject_type(input_obj_arg) != QTYPE_QSTRING) {
+            qerror_report(QERR_QMP_BAD_INPUT_OBJECT_MEMBER, "execute",
+                          "string");
+            *err = -1;
+        }
+    } else if (!strcmp(input_obj_arg_name, "arguments")) {
+        if (qobject_type(input_obj_arg) != QTYPE_QDICT) {
+            qerror_report(QERR_QMP_BAD_INPUT_OBJECT_MEMBER, "arguments",
+                          "object");
+            *err = -1;
+        }
+    } else if (!strcmp(input_obj_arg_name, "id")) {
+        /* nothing to do */
+    } else {
+        qerror_report(QERR_QMP_INVALID_INPUT_OBJECT_MEMBER, input_obj_arg_name);
+        *err = -1;
+    }
+}
+
 static void handle_qmp_command(JSONMessageParser *parser, QList *tokens)
 {
     int err;
@@ -4295,6 +4334,12 @@ static void handle_qmp_command(JSONMessageParser *parser, QList *tokens)
 
     input = qobject_to_qdict(obj);
 
+    err = 0;
+    qdict_iter(input, qmp_check_input_obj, &err);
+    if (err < 0) {
+        goto err_out;
+    }
+
     mon->mc->id = qdict_get(input, "id");
     qobject_incref(mon->mc->id);
 
-- 
1.7.1.231.gd0b16