obj: implement link objects

obj/link.c

@@ -0,0 +1,62 @@
+#include <socks/object.h>
+
+#define LINK_CAST(p) OBJECT_C_CAST(struct link, l_base, &link_type, p)
+
+struct link {
+	struct object l_base;
+	char l_name[OBJECT_NAME_MAX];
+	struct object *l_dest;
+};
+
+static struct object_type link_type;
+
+static kern_status_t link_query_name(struct object *obj, char out[OBJECT_NAME_MAX])
+{
+	struct link *link = LINK_CAST(obj);
+	strncpy(out, link->l_name, OBJECT_NAME_MAX - 1);
+	out[OBJECT_NAME_MAX - 1] = 0;
+
+	return KERN_OK;
+}
+
+static struct object_type link_type = {
+	.ob_name = "link",
+	.ob_size = sizeof(struct link),
+	.ob_header_offset = offsetof(struct link, l_base),
+	.ob_ops = {
+		.query_name = link_query_name,
+	},
+};
+
+void init_link_objects(void)
+{
+	object_type_register(&link_type);
+}
+
+struct object *link_create(const char *name, struct object *dest)
+{
+	struct object *link_obj = object_create(&link_type);
+	if (!link_obj) {
+		return NULL;
+	}
+
+	struct link *link = LINK_CAST(link_obj);
+
+	strncpy(link->l_name, name, sizeof link->l_name - 1);
+	link->l_name[sizeof link->l_name - 1] = 0;
+
+	link->l_dest = object_ref(dest);
+
+	return link_obj;
+}
+
+struct object *link_read_ptr(struct object *link_obj)
+{
+	struct link *link = LINK_CAST(link_obj);
+	return link->l_dest;
+}
+
+bool object_is_link(struct object *obj)
+{
+	return obj->ob_type == &link_type;
+}