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#!/usr/bin/env python
# -*- Mode: python -*-
# Copyright (c) 2009, Andrew McNabb
"""Sends the password over a socket to askpass.
"""
import errno
import getpass
import os
import socket
import sys
import tempfile
import textwrap
from psshlib import psshutil
class PasswordServer(object):
"""Listens on a UNIX domain socket for password requests."""
def __init__(self):
self.sock = None
self.tempdir = None
self.address = None
self.socketmap = {}
self.buffermap = {}
def start(self, iomap, backlog):
"""Prompts for the password, creates a socket, and starts listening.
The specified backlog should be the max number of clients connecting
at once.
"""
message = ('Warning: do not enter your password if anyone else has'
' superuser privileges or access to your account.')
print(textwrap.fill(message))
self.password = getpass.getpass()
# Note that according to the docs for mkdtemp, "The directory is
# readable, writable, and searchable only by the creating user."
self.tempdir = tempfile.mkdtemp(prefix='pssh.')
self.address = os.path.join(self.tempdir, 'pssh_askpass_socket')
self.sock = socket.socket(socket.AF_UNIX)
psshutil.set_cloexec(self.sock)
self.sock.bind(self.address)
self.sock.listen(backlog)
iomap.register_read(self.sock.fileno(), self.handle_listen)
def handle_listen(self, fd, iomap):
try:
conn = self.sock.accept()[0]
except socket.error:
_, e, _ = sys.exc_info()
number = e.args[0]
if number == errno.EINTR:
return
else:
# TODO: print an error message here?
self.sock.close()
self.sock = None
fd = conn.fileno()
iomap.register_write(fd, self.handle_write)
self.socketmap[fd] = conn
self.buffermap[fd] = self.password
def handle_write(self, fd, iomap):
buffer = self.buffermap[fd]
conn = self.socketmap[fd]
try:
bytes_written = conn.send(buffer)
except socket.error:
_, e, _ = sys.exc_info()
number = e.args[0]
if number == errno.EINTR:
return
else:
self.close_socket(fd, iomap)
buffer = buffer[bytes_written:]
if buffer:
self.buffermap[fd] = buffer
else:
self.close_socket(fd, iomap)
def close_socket(self, fd, iomap):
iomap.unregister(fd)
self.socketmap[fd].close()
del self.socketmap[fd]
del self.buffermap[fd]
def __del__(self):
if self.sock:
self.sock.close()
self.sock = None
if self.address:
os.remove(self.address)
if self.tempdir:
os.rmdir(self.tempdir)
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