def secure_filename(filename):
    r"""Borrowed from :mod:`werkzeug.utils`, under the BSD 3-clause license.

    Pass it a filename and it will return a secure version of it.  This
    filename can then safely be stored on a regular file system and passed
    to :func:`os.path.join`.  The filename returned is an ASCII only string
    for maximum portability.

    On windows systems the function also makes sure that the file is not
    named after one of the special device files.

    >>> secure_filename("My cool movie.mov")
    'My_cool_movie.mov'
    >>> secure_filename("../../../etc/passwd")
    'etc_passwd'
    >>> secure_filename(u'i contain cool \xfcml\xe4uts.txt')
    'i_contain_cool_umlauts.txt'

    The function might return an empty filename.  It's your responsibility
    to ensure that the filename is unique and that you generate random
    filename if the function returned an empty one.

    :param filename: the filename to secure
    """
    _filename_ascii_strip_re = re.compile(r'[^A-Za-z0-9_.-]')
    _windows_device_files = ('CON', 'AUX', 'COM1', 'COM2', 'COM3', 'COM4',
                             'LPT1', 'LPT2', 'LPT3', 'PRN', 'NUL')
    if isinstance(filename, text_type):
        from unicodedata import normalize
        filename = normalize('NFKD', filename).encode('ascii', 'ignore')
        if not PY2:
            filename = filename.decode('ascii')
    for sep in os.path.sep, os.path.altsep:
        if sep:
            filename = filename.replace(sep, ' ')
    filename = str(_filename_ascii_strip_re.sub('', '_'.join(
                   filename.split()))).strip('._')

    # on nt a couple of special files are present in each folder.  We
    # have to ensure that the target file is not such a filename.  In
    # this case we prepend an underline
    if os.name == 'nt' and filename and \
       filename.split('.')[0].upper() in _windows_device_files:
        filename = '_' + filename

    return filename
def reset_log_location(cls, new_log_location: str) -> None:
        """Re-acquire file handles to error logs based in the new location.

        Class state:
        - Overwrites `cls._log_dir`, `cls._pid_specific_error_fileobj`, and
          `cls._shared_error_fileobj`.
        OS state:
        - May create a new directory.
        - Overwrites signal handlers for many fatal and non-fatal signals (but not SIGUSR2).

        :raises: :class:`ExceptionSink.ExceptionSinkError` if the directory does not exist or is not
                 writable.
        """
        # We could no-op here if the log locations are the same, but there's no reason not to have the
        # additional safety of re-acquiring file descriptors each time (and erroring out early if the
        # location is no longer writable).
        try:
            safe_mkdir(new_log_location)
        except Exception as e:
            raise cls.ExceptionSinkError(
                "The provided log location path at '{}' is not writable or could not be created: {}.".format(
                    new_log_location, str(e)
                ),
                e,
            )

        pid = os.getpid()
        pid_specific_log_path = cls.exceptions_log_path(for_pid=pid, in_dir=new_log_location)
        shared_log_path = cls.exceptions_log_path(in_dir=new_log_location)
        assert pid_specific_log_path != shared_log_path
        try:
            pid_specific_error_stream = safe_open(pid_specific_log_path, mode="w")
            shared_error_stream = safe_open(shared_log_path, mode="a")
        except Exception as e:
            raise cls.ExceptionSinkError(
                "Error opening fatal error log streams for log location '{}': {}".format(
                    new_log_location, str(e)
                )
            )

        # NB: mutate process-global state!
        if faulthandler.is_enabled():
            logger.debug("re-enabling faulthandler")
            # Call Py_CLEAR() on the previous error stream:
            # https://github.com/vstinner/faulthandler/blob/master/faulthandler.c
            faulthandler.disable()
        # Send a stacktrace to this file if interrupted by a fatal error.
        faulthandler.enable(file=pid_specific_error_stream, all_threads=True)

        # NB: mutate the class variables!
        cls._log_dir = new_log_location
        cls._pid_specific_error_fileobj = pid_specific_error_stream
        cls._shared_error_fileobj = shared_error_stream