#!/usr/bin/env python3

# Copyright (C) 2007 Giampaolo Rodola' <g.rodola@gmail.com>.
# Use of this source code is governed by MIT license that can be
# found in the LICENSE file.

"""A FTPd using local UNIX account database to authenticate users.

It temporarily impersonate the system users every time they are going
to perform a filesystem operations.
"""

from pyftpdlib.authorizers import UnixAuthorizer
from pyftpdlib.filesystems import UnixFilesystem
from pyftpdlib.handlers import FTPHandler
from pyftpdlib.servers import FTPServer


def main():
    authorizer = UnixAuthorizer(
        rejected_users=["root"], require_valid_shell=True
    )
    handler = FTPHandler
    handler.authorizer = authorizer
    handler.abstracted_fs = UnixFilesystem
    server = FTPServer(('', 21), handler)
    server.serve_forever()


if __name__ == "__main__":
    main()