[Qemu-devel] [PATCH v2 10/18] qjson: report an error if there are multiple results

[Marc-André Lureau]

qobject_from_jsonv() returns a single object. Let's make sure that
during parsing we don't leak an intermediary object. Instead of
returning the last object, set a parsing error.

Also, the lexer/parser keeps consuming all the data. There might be an
error set earlier. Let's keep it and not call json_parser_parse() with
the remaining data. Eventually, we may teach the message parser to
stop consuming the data.

Signed-off-by: Marc-André Lureau <address@hidden>
---
 qobject/qjson.c     | 16 +++++++++++++++-
 tests/check-qjson.c | 11 +++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/qobject/qjson.c b/qobject/qjson.c
index ee04e61096..8a9d116150 100644
--- a/qobject/qjson.c
+++ b/qobject/qjson.c
@@ -22,6 +22,7 @@
 #include "qapi/qmp/qlist.h"
 #include "qapi/qmp/qnum.h"
 #include "qapi/qmp/qstring.h"
+#include "qapi/qmp/qerror.h"
 #include "qemu/unicode.h"
 
 typedef struct JSONParsingState
@@ -36,7 +37,20 @@ static void parse_json(JSONMessageParser *parser, GQueue 
*tokens)
 {
     JSONParsingState *s = container_of(parser, JSONParsingState, parser);
 
-    s->result = json_parser_parse(tokens, s->ap, &s->err);
+    if (s->result || s->err) {
+        if (s->result) {
+            qobject_unref(s->result);
+            s->result = NULL;
+            if (!s->err) {
+                error_setg(&s->err, QERR_JSON_PARSING);
+            }
+        }
+        if (tokens) {
+            g_queue_free_full(tokens, g_free);
+        }
+    } else {
+        s->result = json_parser_parse(tokens, s->ap, &s->err);
+    }
 }
 
 QObject *qobject_from_jsonv(const char *string, va_list *ap, Error **errp)
diff --git a/tests/check-qjson.c b/tests/check-qjson.c
index da582df3e9..7d3547e0cc 100644
--- a/tests/check-qjson.c
+++ b/tests/check-qjson.c
@@ -1417,6 +1417,16 @@ static void limits_nesting(void)
     g_assert(obj == NULL);
 }
 
+static void multiple_objects(void)
+{
+    Error *err = NULL;
+    QObject *obj;
+
+    obj = qobject_from_json("{} {}", &err);
+    g_assert(obj == NULL);
+    error_free_or_abort(&err);
+}
+
 int main(int argc, char **argv)
 {
     g_test_init(&argc, &argv, NULL);
@@ -1454,6 +1464,7 @@ int main(int argc, char **argv)
     g_test_add_func("/errors/invalid_dict_comma", invalid_dict_comma);
     g_test_add_func("/errors/unterminated/literal", unterminated_literal);
     g_test_add_func("/errors/limits/nesting", limits_nesting);
+    g_test_add_func("/errors/multiple_objects", multiple_objects);
 
     return g_test_run();
 }
-- 
2.18.0.129.ge3331758f1