[Qemu-devel] [PATCH v15 05/23] qapi: Use strict QMP input visitor in more places

[Eric Blake]

Rather than having two separate ways to create a QMP input
visitor, where the safer approach has the more verbose name,
it is better to consolidate things into a single function
where the caller must explicitly choose whether to be strict
or to ignore excess input.  Use strict mode in more places of
internal code (such as when cloning a QAPI struct in
util/socket.c, where the QObject better not have excess
input since it was just generated by qmp-output), while
documenting in user-facing code a question of whether we
should change our policy about ignoring excess input.

In the case of qmp_object_add(), we intentionally switch to a
strict visitor; this matches the fact that the code for
user_creatable_add_type() is shared by both qmp_object_add()
(QMP input visitor) and by user_creatable_add_opts() (QemuOpts
visitor); the latter is always strict, so our usage in the
former should also be strict, so that both visits will
equally diagnose any excess input in a nested dict.  But in
practice, we don't really have any -object where the
properties are a nested dict, and excess input at the top
level is already caught earlier by object_property_set() on
an unknown key, whether from QemuOpts:

$ ./x86_64-softmmu/qemu-system-x86_64 -nographic -nodefaults -qmp stdio -object 
secret,id=sec0,data=letmein,format=raw,foo=bar
qemu-system-x86_64: Property '.foo' not found

or from QMP:

$ ./x86_64-softmmu/qemu-system-x86_64 -nographic -nodefaults -qmp stdio
{"QMP": {"version": {"qemu": {"micro": 93, "minor": 5, "major": 2}, "package": 
""}, "capabilities": []}}
{"execute":"qmp_capabilities"}
{"return": {}}
{"execute":"object-add","arguments":{"qom-type":"secret","id":"sec0","props":{"format":"raw","data":"letmein","a":1}}}
{"error": {"class": "GenericError", "desc": "Property '.a' not found"}}

Signed-off-by: Eric Blake <address@hidden>

---
v15: new patch
---
 scripts/qapi-commands.py           |  2 +-
 include/qapi/qmp-input-visitor.h   |  9 +++++++--
 qapi/qmp-input-visitor.c           | 13 ++-----------
 qmp.c                              |  2 +-
 qom/qom-qobject.c                  |  3 ++-
 replay/replay-input.c              |  2 +-
 tests/test-qmp-commands.c          |  2 +-
 tests/test-qmp-input-strict.c      |  2 +-
 tests/test-qmp-input-visitor.c     |  2 +-
 tests/test-visitor-serialization.c |  2 +-
 util/qemu-sockets.c                |  2 +-
 docs/qapi-code-gen.txt             |  2 +-
 12 files changed, 20 insertions(+), 23 deletions(-)

diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
index b570069..6261e44 100644
--- a/scripts/qapi-commands.py
+++ b/scripts/qapi-commands.py
@@ -115,7 +115,7 @@ def gen_marshal(name, arg_type, ret_type):

     if arg_type and arg_type.members:
         ret += mcgen('''
-    QmpInputVisitor *qiv = qmp_input_visitor_new_strict(QOBJECT(args));
+    QmpInputVisitor *qiv = qmp_input_visitor_new(QOBJECT(args), true);
     QapiDeallocVisitor *qdv;
     Visitor *v;
     %(c_name)s arg = {0};
diff --git a/include/qapi/qmp-input-visitor.h b/include/qapi/qmp-input-visitor.h
index 3ed499c..b0624d8 100644
--- a/include/qapi/qmp-input-visitor.h
+++ b/include/qapi/qmp-input-visitor.h
@@ -19,8 +19,13 @@

 typedef struct QmpInputVisitor QmpInputVisitor;

-QmpInputVisitor *qmp_input_visitor_new(QObject *obj);
-QmpInputVisitor *qmp_input_visitor_new_strict(QObject *obj);
+/*
+ * Return a new input visitor that converts QMP to QAPI.
+ *
+ * Set @strict to reject a parse that doesn't consume all keys of a
+ * dictionary; otherwise excess input is ignored.
+ */
+QmpInputVisitor *qmp_input_visitor_new(QObject *obj, bool strict);

 void qmp_input_visitor_cleanup(QmpInputVisitor *v);

diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c
index 8550bc7..c3c3271 100644
--- a/qapi/qmp-input-visitor.c
+++ b/qapi/qmp-input-visitor.c
@@ -356,7 +356,7 @@ void qmp_input_visitor_cleanup(QmpInputVisitor *v)
     g_free(v);
 }

-QmpInputVisitor *qmp_input_visitor_new(QObject *obj)
+QmpInputVisitor *qmp_input_visitor_new(QObject *obj, bool strict)
 {
     QmpInputVisitor *v;

@@ -376,19 +376,10 @@ QmpInputVisitor *qmp_input_visitor_new(QObject *obj)
     v->visitor.type_number = qmp_input_type_number;
     v->visitor.type_any = qmp_input_type_any;
     v->visitor.optional = qmp_input_optional;
+    v->strict = strict;

     qmp_input_push(v, obj, NULL);
     qobject_incref(obj);

     return v;
 }
-
-QmpInputVisitor *qmp_input_visitor_new_strict(QObject *obj)
-{
-    QmpInputVisitor *v;
-
-    v = qmp_input_visitor_new(obj);
-    v->strict = true;
-
-    return v;
-}
diff --git a/qmp.c b/qmp.c
index 9d0953b..e784a67 100644
--- a/qmp.c
+++ b/qmp.c
@@ -663,7 +663,7 @@ void qmp_object_add(const char *type, const char *id,
         }
     }

-    qiv = qmp_input_visitor_new(props);
+    qiv = qmp_input_visitor_new(props, true);
     obj = user_creatable_add_type(type, id, pdict,
                                   qmp_input_get_visitor(qiv), errp);
     qmp_input_visitor_cleanup(qiv);
diff --git a/qom/qom-qobject.c b/qom/qom-qobject.c
index e6b17c1..b66088d 100644
--- a/qom/qom-qobject.c
+++ b/qom/qom-qobject.c
@@ -22,7 +22,8 @@ void object_property_set_qobject(Object *obj, QObject *value,
                                  const char *name, Error **errp)
 {
     QmpInputVisitor *qiv;
-    qiv = qmp_input_visitor_new(value);
+    /* TODO: Should we reject, rather than ignore, excess input? */
+    qiv = qmp_input_visitor_new(value, false);
     object_property_set(obj, qmp_input_get_visitor(qiv), name, errp);

     qmp_input_visitor_cleanup(qiv);
diff --git a/replay/replay-input.c b/replay/replay-input.c
index 06babe0..03e99d5 100644
--- a/replay/replay-input.c
+++ b/replay/replay-input.c
@@ -37,7 +37,7 @@ static InputEvent *qapi_clone_InputEvent(InputEvent *src)
         return NULL;
     }

-    qiv = qmp_input_visitor_new(obj);
+    qiv = qmp_input_visitor_new(obj, true);
     iv = qmp_input_get_visitor(qiv);
     visit_type_InputEvent(iv, NULL, &dst, &error_abort);
     qmp_input_visitor_cleanup(qiv);
diff --git a/tests/test-qmp-commands.c b/tests/test-qmp-commands.c
index 14a9ebb..597fb44 100644
--- a/tests/test-qmp-commands.c
+++ b/tests/test-qmp-commands.c
@@ -222,7 +222,7 @@ static void test_dealloc_partial(void)
         ud2_dict = qdict_new();
         qdict_put_obj(ud2_dict, "string0", QOBJECT(qstring_from_str(text)));

-        qiv = qmp_input_visitor_new(QOBJECT(ud2_dict));
+        qiv = qmp_input_visitor_new(QOBJECT(ud2_dict), true);
         visit_type_UserDefTwo(qmp_input_get_visitor(qiv), NULL, &ud2, &err);
         qmp_input_visitor_cleanup(qiv);
         QDECREF(ud2_dict);
diff --git a/tests/test-qmp-input-strict.c b/tests/test-qmp-input-strict.c
index d5f80ec..2b053a2 100644
--- a/tests/test-qmp-input-strict.c
+++ b/tests/test-qmp-input-strict.c
@@ -55,7 +55,7 @@ static Visitor 
*validate_test_init_internal(TestInputVisitorData *data,
     data->obj = qobject_from_jsonv(json_string, ap);
     g_assert(data->obj);

-    data->qiv = qmp_input_visitor_new_strict(data->obj);
+    data->qiv = qmp_input_visitor_new(data->obj, true);
     g_assert(data->qiv);

     v = qmp_input_get_visitor(data->qiv);
diff --git a/tests/test-qmp-input-visitor.c b/tests/test-qmp-input-visitor.c
index 80527eb..c039806 100644
--- a/tests/test-qmp-input-visitor.c
+++ b/tests/test-qmp-input-visitor.c
@@ -51,7 +51,7 @@ static Visitor 
*visitor_input_test_init_internal(TestInputVisitorData *data,
     data->obj = qobject_from_jsonv(json_string, ap);
     g_assert(data->obj);

-    data->qiv = qmp_input_visitor_new(data->obj);
+    data->qiv = qmp_input_visitor_new(data->obj, false);
     g_assert(data->qiv);

     v = qmp_input_get_visitor(data->qiv);
diff --git a/tests/test-visitor-serialization.c 
b/tests/test-visitor-serialization.c
index 9adbc30..7b14b5a 100644
--- a/tests/test-visitor-serialization.c
+++ b/tests/test-visitor-serialization.c
@@ -1038,7 +1038,7 @@ static void qmp_deserialize(void **native_out, void 
*datap,
     obj = qobject_from_json(qstring_get_str(output_json));

     QDECREF(output_json);
-    d->qiv = qmp_input_visitor_new(obj);
+    d->qiv = qmp_input_visitor_new(obj, true);
     qobject_decref(obj_orig);
     qobject_decref(obj);
     visit(qmp_input_get_visitor(d->qiv), native_out, errp);
diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
index 0d53691..2a2c524 100644
--- a/util/qemu-sockets.c
+++ b/util/qemu-sockets.c
@@ -1145,7 +1145,7 @@ void qapi_copy_SocketAddress(SocketAddress **p_dest,
         return;
     }

-    qiv = qmp_input_visitor_new(obj);
+    qiv = qmp_input_visitor_new(obj, true);
     iv = qmp_input_get_visitor(qiv);
     visit_type_SocketAddress(iv, NULL, p_dest, &error_abort);
     qmp_input_visitor_cleanup(qiv);
diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt
index 0e4baff..4a917f9 100644
--- a/docs/qapi-code-gen.txt
+++ b/docs/qapi-code-gen.txt
@@ -996,7 +996,7 @@ Example:
     {
         Error *err = NULL;
         UserDefOne *retval;
-        QmpInputVisitor *qiv = qmp_input_visitor_new_strict(QOBJECT(args));
+        QmpInputVisitor *qiv = qmp_input_visitor_new(QOBJECT(args), true);
         QapiDeallocVisitor *qdv;
         Visitor *v;
         UserDefOneList *arg1 = NULL;
-- 
2.5.5