[BUG] - sftpserver truncate issue when uploading a file through scp about paramiko HOT 2 OPEN

#!/usr/bin/env python3

import logging
import logging.handlers
import sys

import paramiko

import stub_sftp

# based on https://gist.github.com/lonetwin/3b5982cf88c598c0e169
class SocketAdapter(object):
    """ Class that adapts stdout and stdin to the socket api to keep paramiko
        happy
    """
    def __init__(self, stdin, stdout):
        self._stdin  = stdin
        self._stdout = stdout
        self._transport = None

    def send(self, data, flags=0):
        self._stdout.flush()
        self._stdout.buffer.write(data)
        self._stdout.flush()
        return len(data)

    def recv(self, bufsize, flags=0):
        data = self._stdin.buffer.read(bufsize)
        return data

    def close(self):
        self._stdin.close()
        self._stdout.close()

    def settimeout(self, ignored):
        pass

    def get_name(self):
        # required at https://github.com/paramiko/paramiko/blob/master/paramiko/sftp_server.py#L86-L91
        return 'sftp'

    def get_transport(self):
        if not self._transport:
            self._transport = paramiko.transport.Transport(self)
        return self._transport

def main():
    logging.basicConfig(level=logging.DEBUG)
    logger = logging.getLogger()
    logger.setLevel(logging.DEBUG)
    extralog = logging.handlers.RotatingFileHandler('/extralog', maxBytes=1000000)
    extralog.setLevel(logging.DEBUG)
    logger.addHandler(extralog)

    log = logging.getLogger(__name__)
    log.debug('going to setup adapter...')
    server_socket = SocketAdapter(sys.stdin, sys.stdout)

    log.debug('going to setup server...')
    si = paramiko.server.ServerInterface()
    sftp_server = paramiko.sftp_server.SFTPServer(server_socket, 'sftp', server=si, sftp_si=stub_sftp.StubSFTPServer)

    log.debug('going to start server...')
    sftp_server.start()

if __name__ == "__main__":
    main()