qom/object.c, hmp.c: fix string_output_get_string() memory leak

string_output_get_string() uses g_string_free(str, false) to
transfer the 'str' pointer to callers and never free it.
Signed-off-by: NChen Fan <chen.fan.fnst@cn.fujitsu.com>
Reviewed-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: NHu Tao <hutao@cn.fujitsu.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

hmp.c

@@ -1687,6 +1687,7 @@ void hmp_info_memdev(Monitor *mon, const QDict *qdict)
     MemdevList *memdev_list = qmp_query_memdev(&err);
     MemdevList *m = memdev_list;
     StringOutputVisitor *ov;
+    char *str;
     int i = 0;
 
 
@@ -1704,9 +1705,10 @@ void hmp_info_memdev(Monitor *mon, const QDict *qdict)
                        m->value->prealloc ? "true" : "false");
         monitor_printf(mon, "  policy: %s\n",
                        HostMemPolicy_lookup[m->value->policy]);
-        monitor_printf(mon, "  host nodes: %s\n",
-                       string_output_get_string(ov));
+        str = string_output_get_string(ov);
+        monitor_printf(mon, "  host nodes: %s\n", str);
 
+        g_free(str);
         string_output_visitor_cleanup(ov);
         m = m->next;
         i++;

qom/object.c

@@ -938,14 +938,18 @@ int object_property_get_enum(Object *obj, const char *name,
 {
     StringOutputVisitor *sov;
     StringInputVisitor *siv;
+    char *str;
     int ret;
 
     sov = string_output_visitor_new(false);
     object_property_get(obj, string_output_get_visitor(sov), name, errp);
-    siv = string_input_visitor_new(string_output_get_string(sov));
+    str = string_output_get_string(sov);
+    siv = string_input_visitor_new(str);
     string_output_visitor_cleanup(sov);
     visit_type_enum(string_input_get_visitor(siv),
                     &ret, strings, NULL, name, errp);
+
+    g_free(str);
     string_input_visitor_cleanup(siv);
 
     return ret;
@@ -956,13 +960,17 @@ void object_property_get_uint16List(Object *obj, const char *name,
 {
     StringOutputVisitor *ov;
     StringInputVisitor *iv;
+    char *str;
 
     ov = string_output_visitor_new(false);
     object_property_get(obj, string_output_get_visitor(ov),
                         name, errp);
-    iv = string_input_visitor_new(string_output_get_string(ov));
+    str = string_output_get_string(ov);
+    iv = string_input_visitor_new(str);
     visit_type_uint16List(string_input_get_visitor(iv),
                           list, NULL, errp);
+
+    g_free(str);
     string_output_visitor_cleanup(ov);
     string_input_visitor_cleanup(iv);
 }