runtime/Stunnel.py
author Edouard Tisserant <edouard.tisserant@gmail.com>
Wed, 05 Oct 2022 16:10:17 +0200
branchwxPython4
changeset 3617 c3aae4c95bc1
parent 2542 a3ec35ee94e7
child 3750 f62625418bff
permissions -rw-r--r--
Runtime: work around 1s delay added when using twisted reactor's callLater.

Since wxPython4, using wxReactor from non-main thread was producing
exceptions in wxWidget's C++ code. Then reactor.run() was called from
main thread, and runtime's worker was delegating calls to reactor
with callLater(0, callable).

While this worked perfectly with wxReactor, it did introduce an unexplained
1 second delay to each worker call when using nomal linux reactors
(i.e. without wxPython). As a workaround reactor runs in a thread when using
twisted without wxPython
from __future__ import absolute_import
from __future__ import print_function
import os
from binascii import b2a_hqx
try:
    from runtime.spawn_subprocess import call
except ImportError:
    from subprocess import call

restart_stunnel_cmdline = ["/etc/init.d/S50stunnel", "restart"]

_PSKpath = None


def restartStunnel():
    """
    Restart stunnel service using SysV init stript
    to apply new generated credentials
    """
    try:
        call(restart_stunnel_cmdline)
    except OSError:
        print(_("Couldn't restart stunnel service"))


def PSKgen(ID, PSKpath):

    # b2a_hqx output len is 4/3 input len
    secret = os.urandom(192)  # int(256/1.3333)
    secretstring = b2a_hqx(secret)

    PSKstring = ID+":"+secretstring
    with open(PSKpath, 'w') as f:
        f.write(PSKstring)
    restartStunnel()


def ensurePSK(ID, PSKpath):
    global _PSKpath
    _PSKpath = PSKpath
    # check if already there
    if not os.path.exists(PSKpath):
        # create if needed
        PSKgen(ID, PSKpath)


def getPSKID(errorlog):
    if _PSKpath is not None:
        if not os.path.exists(_PSKpath):
            errorlog(
                'Error: Pre-Shared-Key Secret in %s is missing!\n' % _PSKpath)
            return None
        ID, _sep, PSK = open(_PSKpath).read().partition(':')
        PSK = PSK.rstrip('\n\r')
        return (ID, PSK)
    return None