Avoid calling exit in backend now that fpm is used for php since its a pesimization and can break calling scripts assumption on locks.
Lock rc.linkup based on interface to avoid races in between up/down events which might create a loop. This is more a timing issue but better enforce serialization here. check_reload_status forces this but not between start and stop but just between similar events. Probably need to bring more inteligence there.
Remove exit and also properly close open files