varlink: improve compat with varlink C reference implementation

The reference implementation seems to set the 'parameters' field for
method calls to 'null' if nothing is specified on its command line. We
so far only could deal if the parameters field was unset or set to the
empty object. Let's also accept the 'null' type.

diff --git a/src/shared/varlink.c b/src/shared/varlink.c
index 2ba942f30e2a240b1858c379a92182f6539e1fd1..749b644a56c672a193c51dfb4469ade02cb0fa14 100644 (file)
--- a/src/shared/varlink.c
+++ b/src/shared/varlink.c
@@ -1038,12 +1038,25 @@ static int varlink_dispatch_disconnect(Varlink *v) {
 }
 
 static int varlink_sanitize_parameters(JsonVariant **v) {
+        int r;
+
         assert(v);
 
         /* Varlink always wants a parameters list, hence make one if the caller doesn't want any */
         if (!*v)
                 return json_variant_new_object(v, NULL, 0);
-        else if (!json_variant_is_object(*v))
+        if (json_variant_is_null(*v)) {
+                JsonVariant *empty;
+
+                r = json_variant_new_object(&empty, NULL, 0);
+                if (r < 0)
+                        return r;
+
+                json_variant_unref(*v);
+                *v = empty;
+                return 0;
+        }
+        if (!json_variant_is_object(*v))
                 return -EINVAL;
 
         return 0;
@@ -1083,7 +1096,7 @@ static int varlink_dispatch_reply(Varlink *v) {
                 } else if (streq(k, "parameters")) {
                         if (parameters)
                                 goto invalid;
-                        if (!json_variant_is_object(e))
+                        if (!json_variant_is_object(e) && !json_variant_is_null(e))
                                 goto invalid;
 
                         parameters = json_variant_ref(e);
@@ -1256,7 +1269,7 @@ static int varlink_dispatch_method(Varlink *v) {
                 } else if (streq(k, "parameters")) {
                         if (parameters)
                                 goto invalid;
-                        if (!json_variant_is_object(e))
+                        if (!json_variant_is_object(e) && !json_variant_is_null(e))
                                 goto invalid;
 
                         parameters = json_variant_ref(e);