# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Support for asynchronously authenticating using PAM.
"""


import PAM

import getpass, threading, os

from twisted.internet import threads, defer

def pamAuthenticateThread(service, user, conv):
def _conv(items):
from twisted.internet import reactor
try:
d = conv(items)
except:
import traceback
traceback.print_exc()
return
ev = threading.Event()
def cb(r):
ev.r = (1, r)
ev.set()
def eb(e):
ev.r = (0, e)
ev.set()
reactor.callFromThread(d.addCallbacks, cb, eb)
ev.wait()
done = ev.r
if done[0]:
return done[1]
else:
raise done[1].type, done[1].value

return callIntoPAM(service, user, _conv)

def callIntoPAM(service, user, conv):
"""A testing hook.
"""
pam = PAM.pam()
pam.start(service)
pam.set_item(PAM.PAM_USER, user)
pam.set_item(PAM.PAM_CONV, conv)
gid = os.getegid()
uid = os.geteuid()
os.setegid(0)
os.seteuid(0)
try:
pam.authenticate() # these will raise
pam.acct_mgmt()
return 1
finally:
os.setegid(gid)
os.seteuid(uid)

def defConv(items):
resp = []
for i in range(len(items)):
message, kind = items[i]
if kind == 1: # password
p = getpass.getpass(message)
resp.append((p, 0))
elif kind == 2: # text
p = raw_input(message)
resp.append((p, 0))
elif kind in (3,4):
print message
resp.append(("", 0))
else:
return defer.fail('foo')
d = defer.succeed(resp)
return d

def pamAuthenticate(service, user, conv):
return threads.deferToThread(pamAuthenticateThread, service, user, conv)