LOCK_PATH
if (unlink(LOCK_PATH) && errno != ENOENT)
err(1, "unlink %s", LOCK_PATH);
fcntl_fd = open(LOCK_PATH, O_RDWR | O_CREAT, 0666);
if (unlink(LOCK_PATH))
err(1, "unlink %s", LOCK_PATH);
if (unlink(LOCK_PATH) && errno != ENOENT)
err(1, "unlink %s", LOCK_PATH);
flock_fd = open(LOCK_PATH, O_RDWR | O_CREAT, 0666);
if (unlink(LOCK_PATH) && errno != ENOENT)
err(1, "unlink %s", LOCK_PATH);