6
6
# This program is partly derived from an example program for an Avahi
7
7
# service publisher, downloaded from
8
8
# <http://avahi.org/wiki/PythonPublishExample>. This includes the
9
# following functions: "AvahiService.add", "AvahiService.remove",
10
# "server_state_changed", "entry_group_state_changed", and some lines
9
# methods "add" and "remove" in the "AvahiService" class, the
10
# "server_state_changed" and "entry_group_state_changed" functions,
11
# and some lines in "main".
13
13
# Everything else is
14
14
# Copyright © 2007-2008 Teddy Hogeborn & Björn Påhlsson
24
24
# GNU General Public License for more details.
26
26
# You should have received a copy of the GNU General Public License
27
# along with this program. If not, see <http://www.gnu.org/licenses/>.
27
# along with this program. If not, see
28
# <http://www.gnu.org/licenses/>.
29
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# Contact the authors at <mandos@fukt.bsnet.se>.
61
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from dbus.mainloop.glib import DBusGMainLoop
64
# Brief description of the operation of this program:
66
# This server announces itself as a Zeroconf service. Connecting
67
# clients use the TLS protocol, with the unusual quirk that this
68
# server program acts as a TLS "client" while a connecting client acts
69
# as a TLS "server". The client (acting as a TLS "server") must
70
# supply an OpenPGP certificate, and the fingerprint of this
71
# certificate is used by this server to look up (in a list read from a
72
# file at start time) which binary blob to give the client. No other
73
# authentication or authorization is done by this server.
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68
logger = logging.Logger('mandos')
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69
syslogger = logging.handlers.SysLogHandler\
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(facility = logging.handlers.SysLogHandler.LOG_DAEMON)
70
(facility = logging.handlers.SysLogHandler.LOG_DAEMON,
79
72
syslogger.setFormatter(logging.Formatter\
80
('%(levelname)s: %(message)s'))
73
('Mandos: %(levelname)s: %(message)s'))
81
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logger.addHandler(syslogger)
76
console = logging.StreamHandler()
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console.setFormatter(logging.Formatter('%(name)s: %(levelname)s:'
79
logger.addHandler(console)
85
81
class AvahiError(Exception):
86
82
def __init__(self, value):
98
94
class AvahiService(object):
95
"""An Avahi (Zeroconf) service.
100
97
interface: integer; avahi.IF_UNSPEC or an interface index.
101
98
Used to optionally bind to the specified interface.
102
name = string; Example: "Mandos"
103
type = string; Example: "_mandos._tcp".
104
See <http://www.dns-sd.org/ServiceTypes.html>
105
port = integer; what port to announce
106
TXT = list of strings; TXT record for the service
107
domain = string; Domain to publish on, default to .local if empty.
108
host = string; Host to publish records for, default to localhost
110
max_renames = integer; maximum number of renames
111
rename_count = integer; counter so we only rename after collisions
112
a sensible number of times
99
name: string; Example: 'Mandos'
100
type: string; Example: '_mandos._tcp'.
101
See <http://www.dns-sd.org/ServiceTypes.html>
102
port: integer; what port to announce
103
TXT: list of strings; TXT record for the service
104
domain: string; Domain to publish on, default to .local if empty.
105
host: string; Host to publish records for, default is localhost
106
max_renames: integer; maximum number of renames
107
rename_count: integer; counter so we only rename after collisions
108
a sensible number of times
114
110
def __init__(self, interface = avahi.IF_UNSPEC, name = None,
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111
type = None, port = None, TXT = None, domain = "",
116
host = "", max_renames = 12):
117
"""An Avahi (Zeroconf) service. """
112
host = "", max_renames = 32768):
118
113
self.interface = interface
126
121
self.domain = domain
128
123
self.rename_count = 0
124
self.max_renames = max_renames
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def rename(self):
130
126
"""Derived from the Avahi example code"""
131
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if self.rename_count >= self.max_renames:
132
logger.critical(u"No suitable service name found after %i"
133
u" retries, exiting.", rename_count)
128
logger.critical(u"No suitable Zeroconf service name found"
129
u" after %i retries, exiting.",
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131
raise AvahiServiceError("Too many renames")
135
name = server.GetAlternativeServiceName(name)
136
logger.notice(u"Changing name to %r ...", name)
132
self.name = server.GetAlternativeServiceName(self.name)
133
logger.info(u"Changing Zeroconf service name to %r ...",
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syslogger.setFormatter(logging.Formatter\
136
('Mandos (%s): %%(levelname)s:'
137
' %%(message)s' % self.name))
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self.rename_count += 1
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avahi.DBUS_INTERFACE_ENTRY_GROUP)
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group.connect_to_signal('StateChanged',
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entry_group_state_changed)
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logger.debug(u"Adding service '%s' of type '%s' ...",
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logger.debug(u"Adding Zeroconf service '%s' of type '%s' ...",
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service.name, service.type)
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group.AddService(
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158
self.interface, # interface
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fingerprint: string (40 or 32 hexadecimal digits); used to
176
177
uniquely identify the client
177
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secret: bytestring; sent verbatim (over TLS) to client
178
fqdn: string (FQDN); available for use by the checker command
179
host: string; available for use by the checker command
179
180
created: datetime.datetime(); object creation, not client host
180
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last_checked_ok: datetime.datetime() or None if not yet checked OK
181
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timeout: datetime.timedelta(); How long from last_checked_ok
221
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interval = property(lambda self: self._interval,
223
224
del _set_interval
224
def __init__(self, name=None, stop_hook=None, fingerprint=None,
225
secret=None, secfile=None, fqdn=None, timeout=None,
226
interval=-1, checker=None):
227
"""Note: the 'checker' argument sets the 'checker_command'
228
attribute and not the 'checker' attribute.."""
225
def __init__(self, name = None, stop_hook=None, config={}):
226
"""Note: the 'checker' key in 'config' sets the
227
'checker_command' attribute and *not* the 'checker'
230
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logger.debug(u"Creating client %r", self.name)
231
# Uppercase and remove spaces from fingerprint
232
# for later comparison purposes with return value of
233
# the fingerprint() function
234
self.fingerprint = fingerprint.upper().replace(u" ", u"")
231
# Uppercase and remove spaces from fingerprint for later
232
# comparison purposes with return value from the fingerprint()
234
self.fingerprint = config["fingerprint"].upper()\
235
236
logger.debug(u" Fingerprint: %s", self.fingerprint)
237
self.secret = secret.decode(u"base64")
237
if "secret" in config:
238
self.secret = config["secret"].decode(u"base64")
239
elif "secfile" in config:
240
sf = open(config["secfile"])
240
241
self.secret = sf.read()
243
244
raise TypeError(u"No secret or secfile for client %s"
246
self.host = config.get("host", "")
246
247
self.created = datetime.datetime.now()
247
248
self.last_checked_ok = None
248
self.timeout = string_to_delta(timeout)
249
self.interval = string_to_delta(interval)
249
self.timeout = string_to_delta(config["timeout"])
250
self.interval = string_to_delta(config["interval"])
250
251
self.stop_hook = stop_hook
251
252
self.checker = None
252
253
self.checker_initiator_tag = None
253
254
self.stop_initiator_tag = None
254
255
self.checker_callback_tag = None
255
self.check_command = checker
256
self.check_command = config["checker"]
257
258
"""Start this client's checker and timeout hooks"""
258
259
# Schedule a new checker to be started an 'interval' from now,
271
272
The possibility that a client might be restarted is left open,
272
273
but not currently used."""
273
274
# If this client doesn't have a secret, it is already stopped.
275
logger.debug(u"Stopping client %s", self.name)
275
if hasattr(self, "secret") and self.secret:
276
logger.info(u"Stopping client %s", self.name)
276
277
self.secret = None
297
298
self.checker = None
298
299
if os.WIFEXITED(condition) \
299
300
and (os.WEXITSTATUS(condition) == 0):
300
logger.debug(u"Checker for %(name)s succeeded",
301
logger.info(u"Checker for %(name)s succeeded",
302
303
self.last_checked_ok = now
303
304
gobject.source_remove(self.stop_initiator_tag)
304
305
self.stop_initiator_tag = gobject.timeout_add\
308
309
logger.warning(u"Checker for %(name)s crashed?",
311
logger.debug(u"Checker for %(name)s failed",
312
logger.info(u"Checker for %(name)s failed",
313
314
def start_checker(self):
314
315
"""Start a new checker subprocess if one is not running.
315
316
If a checker already exists, leave it running and do
338
339
u' %s', self.check_command, error)
339
340
return True # Try again later
341
logger.debug(u"Starting checker %r for %s",
342
logger.info(u"Starting checker %r for %s",
344
# We don't need to redirect stdout and stderr, since
345
# in normal mode, that is already done by daemon(),
346
# and in debug mode we don't want to. (Stdin is
347
# always replaced by /dev/null.)
343
348
self.checker = subprocess.Popen(command,
345
350
shell=True, cwd="/")
346
351
self.checker_callback_tag = gobject.child_watch_add\
347
352
(self.checker.pid,
348
353
self.checker_callback)
349
except subprocess.OSError, error:
354
except OSError, error:
350
355
logger.error(u"Failed to start subprocess: %s",
352
357
# Re-run this periodically if run by gobject.timeout_add
358
363
self.checker_callback_tag = None
359
364
if getattr(self, "checker", None) is None:
361
logger.debug("Stopping checker for %(name)s", vars(self))
366
logger.debug(u"Stopping checker for %(name)s", vars(self))
363
368
os.kill(self.checker.pid, signal.SIGTERM)
397
402
def fingerprint(openpgp):
398
403
"Convert an OpenPGP bytestring to a hexdigit fingerprint string"
399
# New empty GnuTLS certificate
400
crt = gnutls.library.types.gnutls_openpgp_crt_t()
401
gnutls.library.functions.gnutls_openpgp_crt_init\
403
404
# New GnuTLS "datum" with the OpenPGP public key
404
405
datum = gnutls.library.types.gnutls_datum_t\
405
406
(ctypes.cast(ctypes.c_char_p(openpgp),
406
407
ctypes.POINTER(ctypes.c_ubyte)),
407
408
ctypes.c_uint(len(openpgp)))
409
# New empty GnuTLS certificate
410
crt = gnutls.library.types.gnutls_openpgp_crt_t()
411
gnutls.library.functions.gnutls_openpgp_crt_init\
408
413
# Import the OpenPGP public key into the certificate
409
ret = gnutls.library.functions.gnutls_openpgp_crt_import\
412
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
414
gnutls.library.functions.gnutls_openpgp_crt_import\
415
(crt, ctypes.byref(datum),
416
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
417
# Verify the self signature in the key
418
crtverify = ctypes.c_uint();
419
gnutls.library.functions.gnutls_openpgp_crt_verify_self\
420
(crt, 0, ctypes.byref(crtverify))
421
if crtverify.value != 0:
422
gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
423
raise gnutls.errors.CertificateSecurityError("Verify failed")
413
424
# New buffer for the fingerprint
414
425
buffer = ctypes.create_string_buffer(20)
415
426
buffer_length = ctypes.c_size_t()
431
442
Note: This will run in its own forked process."""
433
444
def handle(self):
434
logger.debug(u"TCP connection from: %s",
445
logger.info(u"TCP connection from: %s",
435
446
unicode(self.client_address))
436
447
session = gnutls.connection.ClientSession\
437
448
(self.request, gnutls.connection.X509Credentials())
450
line = self.request.makefile().readline()
451
logger.debug(u"Protocol version: %r", line)
453
if int(line.strip().split()[0]) > 1:
455
except (ValueError, IndexError, RuntimeError), error:
456
logger.error(u"Unknown protocol version: %s", error)
438
459
# Note: gnutls.connection.X509Credentials is really a generic
439
460
# GnuTLS certificate credentials object so long as no X.509
440
461
# keys are added to it. Therefore, we can use it here despite
454
475
session.handshake()
455
476
except gnutls.errors.GNUTLSError, error:
456
logger.debug(u"Handshake failed: %s", error)
477
logger.warning(u"Handshake failed: %s", error)
457
478
# Do not run session.bye() here: the session is not
458
479
# established. Just abandon the request.
461
482
fpr = fingerprint(peer_certificate(session))
462
483
except (TypeError, gnutls.errors.GNUTLSError), error:
463
logger.debug(u"Bad certificate: %s", error)
484
logger.warning(u"Bad certificate: %s", error)
466
487
logger.debug(u"Fingerprint: %s", fpr)
473
logger.debug(u"Client not found for fingerprint: %s", fpr)
494
logger.warning(u"Client not found for fingerprint: %s",
476
498
# Have to check if client.still_valid(), since it is possible
477
499
# that the client timed out while establishing the GnuTLS
479
501
if not client.still_valid():
480
logger.debug(u"Client %(name)s is invalid", vars(client))
502
logger.warning(u"Client %(name)s is invalid",
504
528
if "clients" in kwargs:
505
529
self.clients = kwargs["clients"]
506
530
del kwargs["clients"]
507
532
return super(type(self), self).__init__(*args, **kwargs)
508
533
def server_bind(self):
509
534
"""This overrides the normal server_bind() function
510
535
to bind to an interface if one was specified, and also NOT to
511
536
bind to an address or port if they were not specified."""
512
if self.settings["interface"] != avahi.IF_UNSPEC:
537
if self.settings["interface"]:
513
538
# 25 is from /usr/include/asm-i486/socket.h
514
539
SO_BINDTODEVICE = getattr(socket, "SO_BINDTODEVICE", 25)
518
543
self.settings["interface"])
519
544
except socket.error, error:
520
545
if error[0] == errno.EPERM:
521
logger.warning(u"No permission to"
522
u" bind to interface %s",
523
self.settings["interface"])
546
logger.error(u"No permission to"
547
u" bind to interface %s",
548
self.settings["interface"])
526
551
# Only bind(2) the socket if we really need to.
529
554
in6addr_any = "::"
530
555
self.server_address = (in6addr_any,
531
556
self.server_address[1])
532
elif self.server_address[1] is None:
557
elif not self.server_address[1]:
533
558
self.server_address = (self.server_address[0],
560
# if self.settings["interface"]:
561
# self.server_address = (self.server_address[0],
535
567
return super(type(self), self).server_bind()
568
def server_activate(self):
570
return super(type(self), self).server_activate()
538
575
def string_to_delta(interval):
548
585
datetime.timedelta(1)
549
586
>>> string_to_delta(u'1w')
550
587
datetime.timedelta(7)
588
>>> string_to_delta('5m 30s')
589
datetime.timedelta(0, 330)
553
suffix=unicode(interval[-1])
554
value=int(interval[:-1])
556
delta = datetime.timedelta(value)
558
delta = datetime.timedelta(0, value)
560
delta = datetime.timedelta(0, 0, 0, 0, value)
562
delta = datetime.timedelta(0, 0, 0, 0, 0, value)
564
delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
591
timevalue = datetime.timedelta(0)
592
for s in interval.split():
594
suffix=unicode(s[-1])
597
delta = datetime.timedelta(value)
599
delta = datetime.timedelta(0, value)
601
delta = datetime.timedelta(0, 0, 0, 0, value)
603
delta = datetime.timedelta(0, 0, 0, 0, 0, value)
605
delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
608
except (ValueError, IndexError):
567
except (ValueError, IndexError):
572
614
def server_state_changed(state):
573
615
"""Derived from the Avahi example code"""
574
616
if state == avahi.SERVER_COLLISION:
575
logger.warning(u"Server name collision")
617
logger.error(u"Zeroconf server name collision")
577
619
elif state == avahi.SERVER_RUNNING:
581
623
def entry_group_state_changed(state, error):
582
624
"""Derived from the Avahi example code"""
583
logger.debug(u"state change: %i", state)
625
logger.debug(u"Avahi state change: %i", state)
585
627
if state == avahi.ENTRY_GROUP_ESTABLISHED:
586
logger.debug(u"Service established.")
628
logger.debug(u"Zeroconf service established.")
587
629
elif state == avahi.ENTRY_GROUP_COLLISION:
588
logger.warning(u"Service name collision.")
630
logger.warning(u"Zeroconf service name collision.")
590
632
elif state == avahi.ENTRY_GROUP_FAILURE:
591
logger.critical(u"Error in group state changed %s",
633
logger.critical(u"Avahi: Error in group state changed %s",
593
635
raise AvahiGroupError("State changed: %s", str(error))
595
def if_nametoindex(interface, _func=[None]):
637
def if_nametoindex(interface):
596
638
"""Call the C function if_nametoindex(), or equivalent"""
597
if _func[0] is not None:
598
return _func[0](interface)
639
global if_nametoindex
600
641
if "ctypes.util" not in sys.modules:
601
642
import ctypes.util
604
libc = ctypes.cdll.LoadLibrary\
605
(ctypes.util.find_library("c"))
606
func[0] = libc.if_nametoindex
607
return _func[0](interface)
643
if_nametoindex = ctypes.cdll.LoadLibrary\
644
(ctypes.util.find_library("c")).if_nametoindex
611
645
except (OSError, AttributeError):
612
646
if "struct" not in sys.modules:
614
648
if "fcntl" not in sys.modules:
616
def the_hard_way(interface):
650
def if_nametoindex(interface):
617
651
"Get an interface index the hard way, i.e. using fcntl()"
618
652
SIOCGIFINDEX = 0x8933 # From /usr/include/linux/sockios.h
619
653
s = socket.socket()
623
657
interface_index = struct.unpack("I", ifreq[16:20])[0]
624
658
return interface_index
625
_func[0] = the_hard_way
626
return _func[0](interface)
629
def daemon(nochdir, noclose):
659
return if_nametoindex(interface)
662
def daemon(nochdir = False, noclose = False):
630
663
"""See daemon(3). Standard BSD Unix function.
631
664
This should really exist as os.daemon, but it doesn't (yet)."""
651
686
global main_loop_started
652
687
main_loop_started = False
654
parser = OptionParser()
689
parser = OptionParser(version = "%%prog %s" % version)
655
690
parser.add_option("-i", "--interface", type="string",
656
691
metavar="IF", help="Bind to interface IF")
657
692
parser.add_option("-a", "--address", type="string",
660
695
help="Port number to receive requests on")
661
696
parser.add_option("--check", action="store_true", default=False,
662
697
help="Run self-test")
663
parser.add_option("--debug", action="store_true", default=False,
698
parser.add_option("--debug", action="store_true",
664
699
help="Debug mode; run in foreground and log to"
666
701
parser.add_option("--priority", type="string", help="GnuTLS"
691
726
# Parse config file for server-global settings
692
727
server_config = ConfigParser.SafeConfigParser(server_defaults)
693
728
del server_defaults
694
server_config.read(os.path.join(options.configdir, "server.conf"))
695
server_section = "server"
729
server_config.read(os.path.join(options.configdir, "mandos.conf"))
696
730
# Convert the SafeConfigParser object to a dict
697
server_settings = dict(server_config.items(server_section))
731
server_settings = server_config.defaults()
698
732
# Use getboolean on the boolean config option
699
733
server_settings["debug"] = server_config.getboolean\
700
(server_section, "debug")
701
735
del server_config
702
if not server_settings["interface"]:
703
server_settings["interface"] = avahi.IF_UNSPEC
705
737
# Override the settings from the config file with command line
706
738
# options, if set.
713
745
# Now we have our good server settings in "server_settings"
747
debug = server_settings["debug"]
750
syslogger.setLevel(logging.WARNING)
751
console.setLevel(logging.WARNING)
753
if server_settings["servicename"] != "Mandos":
754
syslogger.setFormatter(logging.Formatter\
755
('Mandos (%s): %%(levelname)s:'
757
% server_settings["servicename"]))
715
759
# Parse config file with clients
716
760
client_defaults = { "timeout": "1h",
717
761
"interval": "5m",
718
"checker": "fping -q -- %%(fqdn)s",
762
"checker": "fping -q -- %(host)s",
720
765
client_config = ConfigParser.SafeConfigParser(client_defaults)
721
766
client_config.read(os.path.join(server_settings["configdir"],
770
tcp_server = IPv6_TCPServer((server_settings["address"],
771
server_settings["port"]),
773
settings=server_settings,
775
pidfilename = "/var/run/mandos.pid"
777
pidfile = open(pidfilename, "w")
778
except IOError, error:
779
logger.error("Could not open file %r", pidfilename)
784
uid = pwd.getpwnam("mandos").pw_uid
787
uid = pwd.getpwnam("nobody").pw_uid
791
gid = pwd.getpwnam("mandos").pw_gid
794
gid = pwd.getpwnam("nogroup").pw_gid
800
except OSError, error:
801
if error[0] != errno.EPERM:
725
805
service = AvahiService(name = server_settings["servicename"],
726
806
type = "_mandos._tcp", );
807
if server_settings["interface"]:
808
service.interface = if_nametoindex\
809
(server_settings["interface"])
732
815
DBusGMainLoop(set_as_default=True )
733
816
main_loop = gobject.MainLoop()
734
817
bus = dbus.SystemBus()
735
server = dbus.Interface(
736
bus.get_object( avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER ),
737
avahi.DBUS_INTERFACE_SERVER )
818
server = dbus.Interface(bus.get_object(avahi.DBUS_NAME,
819
avahi.DBUS_PATH_SERVER),
820
avahi.DBUS_INTERFACE_SERVER)
738
821
# End of Avahi example code
740
debug = server_settings["debug"]
743
console = logging.StreamHandler()
744
# console.setLevel(logging.DEBUG)
745
console.setFormatter(logging.Formatter\
746
('%(levelname)s: %(message)s'))
747
logger.addHandler(console)
751
823
def remove_from_clients(client):
752
824
clients.remove(client)
754
logger.debug(u"No clients left, exiting")
826
logger.critical(u"No clients left, exiting")
757
clients.update(Set(Client(name=section,
829
clients.update(Set(Client(name = section,
758
830
stop_hook = remove_from_clients,
759
**(dict(client_config\
832
= dict(client_config.items(section)))
761
833
for section in client_config.sections()))
835
logger.critical(u"No clients defined")
839
# Redirect stdin so all checkers get /dev/null
840
null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
841
os.dup2(null, sys.stdin.fileno())
846
logger.removeHandler(console)
847
# Close all input and output, do double fork, etc.
852
pidfile.write(str(pid) + "\n")
856
logger.error(u"Could not write to file %r with PID %d",
859
# "pidfile" was never created
767
864
"Cleanup function; run on exit"
787
884
for client in clients:
790
tcp_server = IPv6_TCPServer((server_settings["address"],
791
server_settings["port"]),
793
settings=server_settings,
888
tcp_server.server_activate()
795
890
# Find out what port we got
796
891
service.port = tcp_server.socket.getsockname()[1]
797
logger.debug(u"Now listening on port %d", service.port)
892
logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
893
u" scope_id %d" % tcp_server.socket.getsockname())
799
if not server_settings["interface"]:
800
service.interface = if_nametoindex\
801
(server_settings["interface"])
895
#service.interface = tcp_server.socket.getsockname()[3]
804
898
# From the Avahi example code