obj: add read() and write() object callbacks

obj/object.c

@@ -121,6 +121,36 @@ struct object *object_header(void *p)
 	return obj;
 }
 
+kern_status_t object_read(struct object *obj, void *p, size_t max,
+                          size_t *nr_read, socks_flags_t flags)
+{
+	kern_status_t status = KERN_UNSUPPORTED;
+
+	if (obj->ob_type->ob_ops.read) {
+		status = obj->ob_type->ob_ops.read(obj, p, &max, flags);
+	} else {
+		max = 0;
+	}
+
+	if (nr_read) {
+		*nr_read = max;
+	}
+
+	return status;
+}
+
+kern_status_t object_write(struct object *obj, const void *p, size_t max,
+                           size_t *nr_written, socks_flags_t flags)
+{
+	kern_status_t status = KERN_UNSUPPORTED;
+
+	if (obj->ob_type->ob_ops.write) {
+		status = obj->ob_type->ob_ops.write(obj, p, &max, flags);
+	}
+
+	return status;
+}
+
 kern_status_t object_get_child_named(struct object *obj, const char *name, struct object **out)
 {
 	kern_status_t status = KERN_UNSUPPORTED;