qapi: check invalid arguments on no-args commands

The generated marshal functions do not visit arguments from commands
that take no arguments. Thus they fail to catch invalid
members. Visit the arguments, if provided, to throw an error in case of
invalid members.

Currently, qmp_check_client_args() checks for invalid arguments and
correctly catches this case. When switching to qmp_dispatch() we want to
keep that behaviour. The commands using 'O' may have arbitrary
arguments, and must have 'gen': false in the qapi schema to skip the
generated checks.

Old/new diff:
 void qmp_marshal_stop(QDict *args, QObject **ret, Error **errp)
 {
     Error *err = NULL;
+    Visitor *v = NULL;

-    (void)args;
+    if (args) {
+        v = qmp_input_visitor_new(QOBJECT(args), true);
+        visit_start_struct(v, NULL, NULL, 0, &err);
+        if (err) {
+            goto out;
+        }
+
+        if (!err) {
+            visit_check_struct(v, &err);
+        }
+        visit_end_struct(v, NULL);
+        if (err) {
+            goto out;
+        }
+    }

     qmp_stop(&err);
+
+out:
     error_propagate(errp, err);
+    visit_free(v);
+    if (args) {
+        v = qapi_dealloc_visitor_new();
+        visit_start_struct(v, NULL, NULL, 0, NULL);
+
+        visit_end_struct(v, NULL);
+        visit_free(v);
+    }
 }

The new code closely resembles code for a command with arguments.
Differences:
- the visit of the argument and its cleanup struct don't visit any
  members (because there are none).
- the visit of the argument struct and its cleanup are conditional.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20160912091913.15831-14-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
index eac64cedc57252da289b87d2e324f5a615d3fdc1..2f603b0c0ed3afda762d22bdca1806e83e2781b9 100644 (file)
--- a/scripts/qapi-commands.py
+++ b/scripts/qapi-commands.py
@@ -95,6 +95,8 @@ def gen_marshal_decl(name):
 
 
 def gen_marshal(name, arg_type, boxed, ret_type):
+    have_args = arg_type and not arg_type.is_empty()
+
     ret = mcgen('''
 
 %(proto)s
@@ -109,17 +111,31 @@ def gen_marshal(name, arg_type, boxed, ret_type):
 ''',
                      c_type=ret_type.c_type())
 
-    if arg_type and not arg_type.is_empty():
+    if have_args:
+        visit_members = ('visit_type_%s_members(v, &arg, &err);'
+                         % arg_type.c_name())
         ret += mcgen('''
     Visitor *v;
     %(c_name)s arg = {0};
 
+''',
+                     c_name=arg_type.c_name())
+    else:
+        visit_members = ''
+        ret += mcgen('''
+    Visitor *v = NULL;
+
+    if (args) {
+''')
+        push_indent()
+
+    ret += mcgen('''
     v = qmp_input_visitor_new(QOBJECT(args), true);
     visit_start_struct(v, NULL, NULL, 0, &err);
     if (err) {
         goto out;
     }
-    visit_type_%(c_name)s_members(v, &arg, &err);
+    %(visit_members)s
     if (!err) {
         visit_check_struct(v, &err);
     }
@@ -128,35 +144,47 @@ def gen_marshal(name, arg_type, boxed, ret_type):
         goto out;
     }
 ''',
-                     c_name=arg_type.c_name())
+                 visit_members=visit_members)
 
-    else:
+    if not have_args:
+        pop_indent()
         ret += mcgen('''
-
-    (void)args;
+    }
 ''')
 
     ret += gen_call(name, arg_type, boxed, ret_type)
 
-    # 'goto out' produced above for arg_type, and by gen_call() for ret_type
-    if (arg_type and not arg_type.is_empty()) or ret_type:
-        ret += mcgen('''
+    ret += mcgen('''
 
 out:
-''')
-    ret += mcgen('''
     error_propagate(errp, err);
+    visit_free(v);
 ''')
-    if arg_type and not arg_type.is_empty():
+
+    if have_args:
+        visit_members = ('visit_type_%s_members(v, &arg, NULL);'
+                         % arg_type.c_name())
+    else:
+        visit_members = ''
         ret += mcgen('''
-    visit_free(v);
+    if (args) {
+''')
+        push_indent()
+
+    ret += mcgen('''
     v = qapi_dealloc_visitor_new();
     visit_start_struct(v, NULL, NULL, 0, NULL);
-    visit_type_%(c_name)s_members(v, &arg, NULL);
+    %(visit_members)s
     visit_end_struct(v, NULL);
     visit_free(v);
 ''',
-                     c_name=arg_type.c_name())
+                 visit_members=visit_members)
+
+    if not have_args:
+        pop_indent()
+        ret += mcgen('''
+    }
+''')
 
     ret += mcgen('''
 }

diff --git a/tests/test-qmp-commands.c b/tests/test-qmp-commands.c
index 261fd9e3130d1a81e80c87ee9124c475532eb3a0..81cbe545c49f73204046caa87bdf83410f37e4ec 100644 (file)
--- a/tests/test-qmp-commands.c
+++ b/tests/test-qmp-commands.c
@@ -106,6 +106,7 @@ static void test_dispatch_cmd(void)
 static void test_dispatch_cmd_failure(void)
 {
     QDict *req = qdict_new();
+    QDict *args = qdict_new();
     QObject *resp;
 
     qdict_put_obj(req, "execute", QOBJECT(qstring_from_str("user_def_cmd2")));
@@ -116,6 +117,20 @@ static void test_dispatch_cmd_failure(void)
 
     qobject_decref(resp);
     QDECREF(req);
+
+    /* check that with extra arguments it throws an error */
+    req = qdict_new();
+    qdict_put(args, "a", qint_from_int(66));
+    qdict_put(req, "arguments", args);
+
+    qdict_put_obj(req, "execute", QOBJECT(qstring_from_str("user_def_cmd")));
+
+    resp = qmp_dispatch(QOBJECT(req));
+    assert(resp != NULL);
+    assert(qdict_haskey(qobject_to_qdict(resp), "error"));
+
+    qobject_decref(resp);
+    QDECREF(req);
 }
 
 static QObject *test_qmp_dispatch(QDict *req)