Keyway: A simple lock library

Maybe I'm missing something, but shouldn't locks generally have some protections against race conditions? E.g. starting from line 15:

    acquire_lock_for() {
      if not_locked $1; then
        lock_log "Creating $1 lock."
        touch "$LOCK_DIR/$1".lock
        check_execution "acquire lock"
      fi
    }

what if another process creates lock file between the `if not_locked` and `touch` lines?