On Tue,  5 Jun 2018 15:08:30 +0200
Nicolas Dichtel [off-list ref] wrote:

 
+char *get_name_from_nsid(int nsid)
+{
+	struct nsid_cache *c;
+
+	netns_nsid_socket_init();
+	netns_map_init();
+
+	c = netns_map_get_by_nsid(nsid);
+	if (c)
+		return c->name;
+
+	return NULL;
+}
+

This is better, but now there is a different problem.
When doing multiple interfaces, won't the initialization code be called twice?