tests: Cover input visit beyond end of list

When you try to visit beyond the end of a list, the qobject input
visitor crashes, and the string visitor screws returns garbage.  The
generated list visits never go beyond the list end, but manual visits
could.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <1488544368-30622-27-git-send-email-armbru@redhat.com>

tests/test-opts-visitor.c

@@ -210,6 +210,43 @@ test_opts_range_unvisited(void)
     qemu_opts_del(opts);
 }
 
+static void
+test_opts_range_beyond(void)
+{
+    Error *err = NULL;
+    intList *list = NULL;
+    intList *tail;
+    QemuOpts *opts;
+    Visitor *v;
+    int64_t val;
+
+    opts = qemu_opts_parse(qemu_find_opts("userdef"), "ilist=0", false,
+                           &error_abort);
+
+    v = opts_visitor_new(opts);
+
+    visit_start_struct(v, NULL, NULL, 0, &error_abort);
+
+    /* Would be simpler if the visitor genuinely supported virtual walks */
+    visit_start_list(v, "ilist", (GenericList **)&list, sizeof(*list),
+                     &error_abort);
+    tail = list;
+    visit_type_int(v, NULL, &tail->value, &error_abort);
+    g_assert_cmpint(tail->value, ==, 0);
+    tail = (intList *)visit_next_list(v, (GenericList *)tail, sizeof(*tail));
+    g_assert(!tail);
+    visit_type_int(v, NULL, &val, &err);
+    error_free_or_abort(&err);
+    visit_end_list(v, (void **)&list);
+
+    visit_check_struct(v, &error_abort);
+    visit_end_struct(v, NULL);
+
+    qapi_free_intList(list);
+    visit_free(v);
+    qemu_opts_del(opts);
+}
+
 int
 main(int argc, char **argv)
 {
@@ -303,6 +340,8 @@ main(int argc, char **argv)
 
     g_test_add_func("/visitor/opts/range/unvisited",
                     test_opts_range_unvisited);
+    g_test_add_func("/visitor/opts/range/beyond",
+                    test_opts_range_beyond);
 
     g_test_run();
     return 0;

tests/test-qobject-input-visitor.c

@@ -948,6 +948,16 @@ static void test_visitor_in_fail_list(TestInputVisitorData *data,
     visit_check_list(v, &err);
     error_free_or_abort(&err);
     visit_end_list(v, NULL);
+
+    /* Visit beyond end of list */
+    v = visitor_input_test_init(data, "[]");
+
+    visit_start_list(v, NULL, NULL, 0, &error_abort);
+#if 0 /* FIXME crash */
+    visit_type_int(v, NULL, &i64, &err);
+    error_free_or_abort(&err);
+#endif
+    visit_end_list(v, NULL);
 }
 
 static void test_visitor_in_fail_list_nested(TestInputVisitorData *data,

tests/test-string-input-visitor.c

@@ -123,6 +123,7 @@ static void test_visitor_in_intList(TestInputVisitorData *data,
     int64List *res = NULL;
     int64List *tail;
     Visitor *v;
+    int64_t val;
 
     /* Valid lists */
 
@@ -175,6 +176,21 @@ static void test_visitor_in_intList(TestInputVisitorData *data,
     visit_end_list(v, (void **)&res);
 
     qapi_free_int64List(res);
+
+    /* Visit beyond end of list */
+    v = visitor_input_test_init(data, "0");
+
+    visit_start_list(v, NULL, (GenericList **)&res, sizeof(*res),
+                     &error_abort);
+    tail = res;
+    visit_type_int64(v, NULL, &tail->value, &err);
+    g_assert_cmpint(tail->value, ==, 0);
+    visit_type_int64(v, NULL, &val, &err);
+    g_assert_cmpint(val, ==, 1); /* BUG */
+    visit_check_list(v, &error_abort);
+    visit_end_list(v, (void **)&res);
+
+    qapi_free_int64List(res);
 }
 
 static void test_visitor_in_bool(TestInputVisitorData *data,