/mandos/release

To get this branch, use:
bzr branch http://bzr.recompile.se/loggerhead/mandos/release
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
#!/usr/bin/python
# -*- mode: python; coding: utf-8 -*-
# 
# Mandos server - give out binary blobs to connecting clients.
# 
# This program is partly derived from an example program for an Avahi
# service publisher, downloaded from
# <http://avahi.org/wiki/PythonPublishExample>.  This includes the
# methods "add", "remove", "server_state_changed",
# "entry_group_state_changed", "cleanup", and "activate" in the
# "AvahiService" class, and some lines in "main".
# 
# Everything else is
# Copyright © 2008-2011 Teddy Hogeborn
# Copyright © 2008-2011 Björn Påhlsson
# 
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
#     This program is distributed in the hope that it will be useful,
#     but WITHOUT ANY WARRANTY; without even the implied warranty of
#     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#     GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see
# <http://www.gnu.org/licenses/>.
# 
# Contact the authors at <mandos@recompile.se>.
# 

from __future__ import (division, absolute_import, print_function,
                        unicode_literals)

import SocketServer as socketserver
import socket
import argparse
import datetime
import errno
import gnutls.crypto
import gnutls.connection
import gnutls.errors
import gnutls.library.functions
import gnutls.library.constants
import gnutls.library.types
import ConfigParser as configparser
import sys
import re
import os
import signal
import subprocess
import atexit
import stat
import logging
import logging.handlers
import pwd
import contextlib
import struct
import fcntl
import functools
import cPickle as pickle
import multiprocessing
import types

import dbus
import dbus.service
import gobject
import avahi
from dbus.mainloop.glib import DBusGMainLoop
import ctypes
import ctypes.util
import xml.dom.minidom
import inspect

try:
    SO_BINDTODEVICE = socket.SO_BINDTODEVICE
except AttributeError:
    try:
        from IN import SO_BINDTODEVICE
    except ImportError:
        SO_BINDTODEVICE = None


version = "1.3.1"

#logger = logging.getLogger('mandos')
logger = logging.Logger('mandos')
syslogger = (logging.handlers.SysLogHandler
             (facility = logging.handlers.SysLogHandler.LOG_DAEMON,
              address = str("/dev/log")))
syslogger.setFormatter(logging.Formatter
                       ('Mandos [%(process)d]: %(levelname)s:'
                        ' %(message)s'))
logger.addHandler(syslogger)

console = logging.StreamHandler()
console.setFormatter(logging.Formatter('%(name)s [%(process)d]:'
                                       ' %(levelname)s:'
                                       ' %(message)s'))
logger.addHandler(console)

class AvahiError(Exception):
    def __init__(self, value, *args, **kwargs):
        self.value = value
        super(AvahiError, self).__init__(value, *args, **kwargs)
    def __unicode__(self):
        return unicode(repr(self.value))

class AvahiServiceError(AvahiError):
    pass

class AvahiGroupError(AvahiError):
    pass


class AvahiService(object):
    """An Avahi (Zeroconf) service.
    
    Attributes:
    interface: integer; avahi.IF_UNSPEC or an interface index.
               Used to optionally bind to the specified interface.
    name: string; Example: 'Mandos'
    type: string; Example: '_mandos._tcp'.
                  See <http://www.dns-sd.org/ServiceTypes.html>
    port: integer; what port to announce
    TXT: list of strings; TXT record for the service
    domain: string; Domain to publish on, default to .local if empty.
    host: string; Host to publish records for, default is localhost
    max_renames: integer; maximum number of renames
    rename_count: integer; counter so we only rename after collisions
                  a sensible number of times
    group: D-Bus Entry Group
    server: D-Bus Server
    bus: dbus.SystemBus()
    """
    def __init__(self, interface = avahi.IF_UNSPEC, name = None,
                 servicetype = None, port = None, TXT = None,
                 domain = "", host = "", max_renames = 32768,
                 protocol = avahi.PROTO_UNSPEC, bus = None):
        self.interface = interface
        self.name = name
        self.type = servicetype
        self.port = port
        self.TXT = TXT if TXT is not None else []
        self.domain = domain
        self.host = host
        self.rename_count = 0
        self.max_renames = max_renames
        self.protocol = protocol
        self.group = None       # our entry group
        self.server = None
        self.bus = bus
        self.entry_group_state_changed_match = None
    def rename(self):
        """Derived from the Avahi example code"""
        if self.rename_count >= self.max_renames:
            logger.critical("No suitable Zeroconf service name found"
                            " after %i retries, exiting.",
                            self.rename_count)
            raise AvahiServiceError("Too many renames")
        self.name = unicode(self.server
                            .GetAlternativeServiceName(self.name))
        logger.info("Changing Zeroconf service name to %r ...",
                    self.name)
        syslogger.setFormatter(logging.Formatter
                               ('Mandos (%s) [%%(process)d]:'
                                ' %%(levelname)s: %%(message)s'
                                % self.name))
        self.remove()
        try:
            self.add()
        except dbus.exceptions.DBusException as error:
            logger.critical("DBusException: %s", error)
            self.cleanup()
            os._exit(1)
        self.rename_count += 1
    def remove(self):
        """Derived from the Avahi example code"""
        if self.entry_group_state_changed_match is not None:
            self.entry_group_state_changed_match.remove()
            self.entry_group_state_changed_match = None
        if self.group is not None:
            self.group.Reset()
    def add(self):
        """Derived from the Avahi example code"""
        self.remove()
        if self.group is None:
            self.group = dbus.Interface(
                self.bus.get_object(avahi.DBUS_NAME,
                                    self.server.EntryGroupNew()),
                avahi.DBUS_INTERFACE_ENTRY_GROUP)
        self.entry_group_state_changed_match = (
            self.group.connect_to_signal(
                'StateChanged', self .entry_group_state_changed))
        logger.debug("Adding Zeroconf service '%s' of type '%s' ...",
                     self.name, self.type)
        self.group.AddService(
            self.interface,
            self.protocol,
            dbus.UInt32(0),     # flags
            self.name, self.type,
            self.domain, self.host,
            dbus.UInt16(self.port),
            avahi.string_array_to_txt_array(self.TXT))
        self.group.Commit()
    def entry_group_state_changed(self, state, error):
        """Derived from the Avahi example code"""
        logger.debug("Avahi entry group state change: %i", state)
        
        if state == avahi.ENTRY_GROUP_ESTABLISHED:
            logger.debug("Zeroconf service established.")
        elif state == avahi.ENTRY_GROUP_COLLISION:
            logger.info("Zeroconf service name collision.")
            self.rename()
        elif state == avahi.ENTRY_GROUP_FAILURE:
            logger.critical("Avahi: Error in group state changed %s",
                            unicode(error))
            raise AvahiGroupError("State changed: %s"
                                  % unicode(error))
    def cleanup(self):
        """Derived from the Avahi example code"""
        if self.group is not None:
            try:
                self.group.Free()
            except (dbus.exceptions.UnknownMethodException,
                    dbus.exceptions.DBusException) as e:
                pass
            self.group = None
        self.remove()
    def server_state_changed(self, state, error=None):
        """Derived from the Avahi example code"""
        logger.debug("Avahi server state change: %i", state)
        bad_states = { avahi.SERVER_INVALID:
                           "Zeroconf server invalid",
                       avahi.SERVER_REGISTERING: None,
                       avahi.SERVER_COLLISION:
                           "Zeroconf server name collision",
                       avahi.SERVER_FAILURE:
                           "Zeroconf server failure" }
        if state in bad_states:
            if bad_states[state] is not None:
                if error is None:
                    logger.error(bad_states[state])
                else:
                    logger.error(bad_states[state] + ": %r", error)
            self.cleanup()
        elif state == avahi.SERVER_RUNNING:
            self.add()
        else:
            if error is None:
                logger.debug("Unknown state: %r", state)
            else:
                logger.debug("Unknown state: %r: %r", state, error)
    def activate(self):
        """Derived from the Avahi example code"""
        if self.server is None:
            self.server = dbus.Interface(
                self.bus.get_object(avahi.DBUS_NAME,
                                    avahi.DBUS_PATH_SERVER,
                                    follow_name_owner_changes=True),
                avahi.DBUS_INTERFACE_SERVER)
        self.server.connect_to_signal("StateChanged",
                                 self.server_state_changed)
        self.server_state_changed(self.server.GetState())


def _timedelta_to_milliseconds(td):
    "Convert a datetime.timedelta() to milliseconds"
    return ((td.days * 24 * 60 * 60 * 1000)
            + (td.seconds * 1000)
            + (td.microseconds // 1000))
        
class Client(object):
    """A representation of a client host served by this server.
    
    Attributes:
    _approved:   bool(); 'None' if not yet approved/disapproved
    approval_delay: datetime.timedelta(); Time to wait for approval
    approval_duration: datetime.timedelta(); Duration of one approval
    checker:    subprocess.Popen(); a running checker process used
                                    to see if the client lives.
                                    'None' if no process is running.
    checker_callback_tag: a gobject event source tag, or None
    checker_command: string; External command which is run to check
                     if client lives.  %() expansions are done at
                     runtime with vars(self) as dict, so that for
                     instance %(name)s can be used in the command.
    checker_initiator_tag: a gobject event source tag, or None
    created:    datetime.datetime(); (UTC) object creation
    current_checker_command: string; current running checker_command
    disable_hook:  If set, called by disable() as disable_hook(self)
    disable_initiator_tag: a gobject event source tag, or None
    enabled:    bool()
    fingerprint: string (40 or 32 hexadecimal digits); used to
                 uniquely identify the client
    host:       string; available for use by the checker command
    interval:   datetime.timedelta(); How often to start a new checker
    last_approval_request: datetime.datetime(); (UTC) or None
    last_checked_ok: datetime.datetime(); (UTC) or None
    last_enabled: datetime.datetime(); (UTC)
    name:       string; from the config file, used in log messages and
                        D-Bus identifiers
    secret:     bytestring; sent verbatim (over TLS) to client
    timeout:    datetime.timedelta(); How long from last_checked_ok
                                      until this client is disabled
    extended_timeout:   extra long timeout when password has been sent
    runtime_expansions: Allowed attributes for runtime expansion.
    expires:    datetime.datetime(); time (UTC) when a client will be
                disabled, or None
    """
    
    runtime_expansions = ("approval_delay", "approval_duration",
                          "created", "enabled", "fingerprint",
                          "host", "interval", "last_checked_ok",
                          "last_enabled", "name", "timeout")
    
    def timeout_milliseconds(self):
        "Return the 'timeout' attribute in milliseconds"
        return _timedelta_to_milliseconds(self.timeout)
    
    def extended_timeout_milliseconds(self):
        "Return the 'extended_timeout' attribute in milliseconds"
        return _timedelta_to_milliseconds(self.extended_timeout)
    
    def interval_milliseconds(self):
        "Return the 'interval' attribute in milliseconds"
        return _timedelta_to_milliseconds(self.interval)
    
    def approval_delay_milliseconds(self):
        return _timedelta_to_milliseconds(self.approval_delay)
    
    def __init__(self, name = None, disable_hook=None, config=None):
        """Note: the 'checker' key in 'config' sets the
        'checker_command' attribute and *not* the 'checker'
        attribute."""
        self.name = name
        if config is None:
            config = {}
        logger.debug("Creating client %r", self.name)
        # Uppercase and remove spaces from fingerprint for later
        # comparison purposes with return value from the fingerprint()
        # function
        self.fingerprint = (config["fingerprint"].upper()
                            .replace(" ", ""))
        logger.debug("  Fingerprint: %s", self.fingerprint)
        if "secret" in config:
            self.secret = config["secret"].decode("base64")
        elif "secfile" in config:
            with open(os.path.expanduser(os.path.expandvars
                                         (config["secfile"])),
                      "rb") as secfile:
                self.secret = secfile.read()
        else:
            raise TypeError("No secret or secfile for client %s"
                            % self.name)
        self.host = config.get("host", "")
        self.created = datetime.datetime.utcnow()
        self.enabled = False
        self.last_approval_request = None
        self.last_enabled = None
        self.last_checked_ok = None
        self.timeout = string_to_delta(config["timeout"])
        self.extended_timeout = string_to_delta(config
                                                ["extended_timeout"])
        self.interval = string_to_delta(config["interval"])
        self.disable_hook = disable_hook
        self.checker = None
        self.checker_initiator_tag = None
        self.disable_initiator_tag = None
        self.expires = None
        self.checker_callback_tag = None
        self.checker_command = config["checker"]
        self.current_checker_command = None
        self.last_connect = None
        self._approved = None
        self.approved_by_default = config.get("approved_by_default",
                                              True)
        self.approvals_pending = 0
        self.approval_delay = string_to_delta(
            config["approval_delay"])
        self.approval_duration = string_to_delta(
            config["approval_duration"])
        self.changedstate = (multiprocessing_manager
                             .Condition(multiprocessing_manager
                                        .Lock()))
    
    def send_changedstate(self):
        self.changedstate.acquire()
        self.changedstate.notify_all()
        self.changedstate.release()
    
    def enable(self):
        """Start this client's checker and timeout hooks"""
        if getattr(self, "enabled", False):
            # Already enabled
            return
        self.send_changedstate()
        # Schedule a new checker to be started an 'interval' from now,
        # and every interval from then on.
        self.checker_initiator_tag = (gobject.timeout_add
                                      (self.interval_milliseconds(),
                                       self.start_checker))
        # Schedule a disable() when 'timeout' has passed
        self.expires = datetime.datetime.utcnow() + self.timeout
        self.disable_initiator_tag = (gobject.timeout_add
                                   (self.timeout_milliseconds(),
                                    self.disable))
        self.enabled = True
        self.last_enabled = datetime.datetime.utcnow()
        # Also start a new checker *right now*.
        self.start_checker()
    
    def disable(self, quiet=True):
        """Disable this client."""
        if not getattr(self, "enabled", False):
            return False
        if not quiet:
            self.send_changedstate()
        if not quiet:
            logger.info("Disabling client %s", self.name)
        if getattr(self, "disable_initiator_tag", False):
            gobject.source_remove(self.disable_initiator_tag)
            self.disable_initiator_tag = None
        self.expires = None
        if getattr(self, "checker_initiator_tag", False):
            gobject.source_remove(self.checker_initiator_tag)
            self.checker_initiator_tag = None
        self.stop_checker()
        if self.disable_hook:
            self.disable_hook(self)
        self.enabled = False
        # Do not run this again if called by a gobject.timeout_add
        return False
    
    def __del__(self):
        self.disable_hook = None
        self.disable()
    
    def checker_callback(self, pid, condition, command):
        """The checker has completed, so take appropriate actions."""
        self.checker_callback_tag = None
        self.checker = None
        if os.WIFEXITED(condition):
            exitstatus = os.WEXITSTATUS(condition)
            if exitstatus == 0:
                logger.info("Checker for %(name)s succeeded",
                            vars(self))
                self.checked_ok()
            else:
                logger.info("Checker for %(name)s failed",
                            vars(self))
        else:
            logger.warning("Checker for %(name)s crashed?",
                           vars(self))
    
    def checked_ok(self, timeout=None):
        """Bump up the timeout for this client.
        
        This should only be called when the client has been seen,
        alive and well.
        """
        if timeout is None:
            timeout = self.timeout
        self.last_checked_ok = datetime.datetime.utcnow()
        gobject.source_remove(self.disable_initiator_tag)
        self.expires = datetime.datetime.utcnow() + timeout
        self.disable_initiator_tag = (gobject.timeout_add
                                      (_timedelta_to_milliseconds
                                       (timeout), self.disable))
    
    def need_approval(self):
        self.last_approval_request = datetime.datetime.utcnow()
    
    def start_checker(self):
        """Start a new checker subprocess if one is not running.
        
        If a checker already exists, leave it running and do
        nothing."""
        # The reason for not killing a running checker is that if we
        # did that, then if a checker (for some reason) started
        # running slowly and taking more than 'interval' time, the
        # client would inevitably timeout, since no checker would get
        # a chance to run to completion.  If we instead leave running
        # checkers alone, the checker would have to take more time
        # than 'timeout' for the client to be disabled, which is as it
        # should be.
        
        # If a checker exists, make sure it is not a zombie
        try:
            pid, status = os.waitpid(self.checker.pid, os.WNOHANG)
        except (AttributeError, OSError) as error:
            if (isinstance(error, OSError)
                and error.errno != errno.ECHILD):
                raise error
        else:
            if pid:
                logger.warning("Checker was a zombie")
                gobject.source_remove(self.checker_callback_tag)
                self.checker_callback(pid, status,
                                      self.current_checker_command)
        # Start a new checker if needed
        if self.checker is None:
            try:
                # In case checker_command has exactly one % operator
                command = self.checker_command % self.host
            except TypeError:
                # Escape attributes for the shell
                escaped_attrs = dict(
                    (attr,
                     re.escape(unicode(str(getattr(self, attr, "")),
                                       errors=
                                       'replace')))
                    for attr in
                    self.runtime_expansions)
                
                try:
                    command = self.checker_command % escaped_attrs
                except TypeError as error:
                    logger.error('Could not format string "%s":'
                                 ' %s', self.checker_command, error)
                    return True # Try again later
            self.current_checker_command = command
            try:
                logger.info("Starting checker %r for %s",
                            command, self.name)
                # We don't need to redirect stdout and stderr, since
                # in normal mode, that is already done by daemon(),
                # and in debug mode we don't want to.  (Stdin is
                # always replaced by /dev/null.)
                self.checker = subprocess.Popen(command,
                                                close_fds=True,
                                                shell=True, cwd="/")
                self.checker_callback_tag = (gobject.child_watch_add
                                             (self.checker.pid,
                                              self.checker_callback,
                                              data=command))
                # The checker may have completed before the gobject
                # watch was added.  Check for this.
                pid, status = os.waitpid(self.checker.pid, os.WNOHANG)
                if pid:
                    gobject.source_remove(self.checker_callback_tag)
                    self.checker_callback(pid, status, command)
            except OSError as error:
                logger.error("Failed to start subprocess: %s",
                             error)
        # Re-run this periodically if run by gobject.timeout_add
        return True
    
    def stop_checker(self):
        """Force the checker process, if any, to stop."""
        if self.checker_callback_tag:
            gobject.source_remove(self.checker_callback_tag)
            self.checker_callback_tag = None
        if getattr(self, "checker", None) is None:
            return
        logger.debug("Stopping checker for %(name)s", vars(self))
        try:
            os.kill(self.checker.pid, signal.SIGTERM)
            #time.sleep(0.5)
            #if self.checker.poll() is None:
            #    os.kill(self.checker.pid, signal.SIGKILL)
        except OSError as error:
            if error.errno != errno.ESRCH: # No such process
                raise
        self.checker = None


def dbus_service_property(dbus_interface, signature="v",
                          access="readwrite", byte_arrays=False):
    """Decorators for marking methods of a DBusObjectWithProperties to
    become properties on the D-Bus.
    
    The decorated method will be called with no arguments by "Get"
    and with one argument by "Set".
    
    The parameters, where they are supported, are the same as
    dbus.service.method, except there is only "signature", since the
    type from Get() and the type sent to Set() is the same.
    """
    # Encoding deeply encoded byte arrays is not supported yet by the
    # "Set" method, so we fail early here:
    if byte_arrays and signature != "ay":
        raise ValueError("Byte arrays not supported for non-'ay'"
                         " signature %r" % signature)
    def decorator(func):
        func._dbus_is_property = True
        func._dbus_interface = dbus_interface
        func._dbus_signature = signature
        func._dbus_access = access
        func._dbus_name = func.__name__
        if func._dbus_name.endswith("_dbus_property"):
            func._dbus_name = func._dbus_name[:-14]
        func._dbus_get_args_options = {'byte_arrays': byte_arrays }
        return func
    return decorator


class DBusPropertyException(dbus.exceptions.DBusException):
    """A base class for D-Bus property-related exceptions
    """
    def __unicode__(self):
        return unicode(str(self))


class DBusPropertyAccessException(DBusPropertyException):
    """A property's access permissions disallows an operation.
    """
    pass


class DBusPropertyNotFound(DBusPropertyException):
    """An attempt was made to access a non-existing property.
    """
    pass


class DBusObjectWithProperties(dbus.service.Object):
    """A D-Bus object with properties.
    
    Classes inheriting from this can use the dbus_service_property
    decorator to expose methods as D-Bus properties.  It exposes the
    standard Get(), Set(), and GetAll() methods on the D-Bus.
    """
    
    @staticmethod
    def _is_dbus_property(obj):
        return getattr(obj, "_dbus_is_property", False)
    
    def _get_all_dbus_properties(self):
        """Returns a generator of (name, attribute) pairs
        """
        return ((prop.__get__(self)._dbus_name, prop.__get__(self))
                for cls in self.__class__.__mro__
                for name, prop in
                inspect.getmembers(cls, self._is_dbus_property))
    
    def _get_dbus_property(self, interface_name, property_name):
        """Returns a bound method if one exists which is a D-Bus
        property with the specified name and interface.
        """
        for cls in  self.__class__.__mro__:
            for name, value in (inspect.getmembers
                                (cls, self._is_dbus_property)):
                if (value._dbus_name == property_name
                    and value._dbus_interface == interface_name):
                    return value.__get__(self)
        
        # No such property
        raise DBusPropertyNotFound(self.dbus_object_path + ":"
                                   + interface_name + "."
                                   + property_name)
    
    @dbus.service.method(dbus.PROPERTIES_IFACE, in_signature="ss",
                         out_signature="v")
    def Get(self, interface_name, property_name):
        """Standard D-Bus property Get() method, see D-Bus standard.
        """
        prop = self._get_dbus_property(interface_name, property_name)
        if prop._dbus_access == "write":
            raise DBusPropertyAccessException(property_name)
        value = prop()
        if not hasattr(value, "variant_level"):
            return value
        return type(value)(value, variant_level=value.variant_level+1)
    
    @dbus.service.method(dbus.PROPERTIES_IFACE, in_signature="ssv")
    def Set(self, interface_name, property_name, value):
        """Standard D-Bus property Set() method, see D-Bus standard.
        """
        prop = self._get_dbus_property(interface_name, property_name)
        if prop._dbus_access == "read":
            raise DBusPropertyAccessException(property_name)
        if prop._dbus_get_args_options["byte_arrays"]:
            # The byte_arrays option is not supported yet on
            # signatures other than "ay".
            if prop._dbus_signature != "ay":
                raise ValueError
            value = dbus.ByteArray(''.join(unichr(byte)
                                           for byte in value))
        prop(value)
    
    @dbus.service.method(dbus.PROPERTIES_IFACE, in_signature="s",
                         out_signature="a{sv}")
    def GetAll(self, interface_name):
        """Standard D-Bus property GetAll() method, see D-Bus
        standard.
        
        Note: Will not include properties with access="write".
        """
        all = {}
        for name, prop in self._get_all_dbus_properties():
            if (interface_name
                and interface_name != prop._dbus_interface):
                # Interface non-empty but did not match
                continue
            # Ignore write-only properties
            if prop._dbus_access == "write":
                continue
            value = prop()
            if not hasattr(value, "variant_level"):
                all[name] = value
                continue
            all[name] = type(value)(value, variant_level=
                                    value.variant_level+1)
        return dbus.Dictionary(all, signature="sv")
    
    @dbus.service.method(dbus.INTROSPECTABLE_IFACE,
                         out_signature="s",
                         path_keyword='object_path',
                         connection_keyword='connection')
    def Introspect(self, object_path, connection):
        """Standard D-Bus method, overloaded to insert property tags.
        """
        xmlstring = dbus.service.Object.Introspect(self, object_path,
                                                   connection)
        try:
            document = xml.dom.minidom.parseString(xmlstring)
            def make_tag(document, name, prop):
                e = document.createElement("property")
                e.setAttribute("name", name)
                e.setAttribute("type", prop._dbus_signature)
                e.setAttribute("access", prop._dbus_access)
                return e
            for if_tag in document.getElementsByTagName("interface"):
                for tag in (make_tag(document, name, prop)
                            for name, prop
                            in self._get_all_dbus_properties()
                            if prop._dbus_interface
                            == if_tag.getAttribute("name")):
                    if_tag.appendChild(tag)
                # Add the names to the return values for the
                # "org.freedesktop.DBus.Properties" methods
                if (if_tag.getAttribute("name")
                    == "org.freedesktop.DBus.Properties"):
                    for cn in if_tag.getElementsByTagName("method"):
                        if cn.getAttribute("name") == "Get":
                            for arg in cn.getElementsByTagName("arg"):
                                if (arg.getAttribute("direction")
                                    == "out"):
                                    arg.setAttribute("name", "value")
                        elif cn.getAttribute("name") == "GetAll":
                            for arg in cn.getElementsByTagName("arg"):
                                if (arg.getAttribute("direction")
                                    == "out"):
                                    arg.setAttribute("name", "props")
            xmlstring = document.toxml("utf-8")
            document.unlink()
        except (AttributeError, xml.dom.DOMException,
                xml.parsers.expat.ExpatError) as error:
            logger.error("Failed to override Introspection method",
                         error)
        return xmlstring


def datetime_to_dbus (dt, variant_level=0):
    """Convert a UTC datetime.datetime() to a D-Bus type."""
    if dt is None:
        return dbus.String("", variant_level = variant_level)
    return dbus.String(dt.isoformat(),
                       variant_level=variant_level)

class AlternateDBusNamesMetaclass(DBusObjectWithProperties
                                  .__metaclass__):
    """Applied to an empty subclass of a D-Bus object, this metaclass
    will add additional D-Bus attributes matching a certain pattern.
    """
    def __new__(mcs, name, bases, attr):
        # Go through all the base classes which could have D-Bus
        # methods, signals, or properties in them
        for base in (b for b in bases
                     if issubclass(b, dbus.service.Object)):
            # Go though all attributes of the base class
            for attrname, attribute in inspect.getmembers(base):
                # Ignore non-D-Bus attributes, and D-Bus attributes
                # with the wrong interface name
                if (not hasattr(attribute, "_dbus_interface")
                    or not attribute._dbus_interface
                    .startswith("se.recompile.Mandos")):
                    continue
                # Create an alternate D-Bus interface name based on
                # the current name
                alt_interface = (attribute._dbus_interface
                                 .replace("se.recompile.Mandos",
                                          "se.bsnet.fukt.Mandos"))
                # Is this a D-Bus signal?
                if getattr(attribute, "_dbus_is_signal", False):
                    # Extract the original non-method function by
                    # black magic
                    nonmethod_func = (dict(
                            zip(attribute.func_code.co_freevars,
                                attribute.__closure__))["func"]
                                      .cell_contents)
                    # Create a new, but exactly alike, function
                    # object, and decorate it to be a new D-Bus signal
                    # with the alternate D-Bus interface name
                    new_function = (dbus.service.signal
                                    (alt_interface,
                                     attribute._dbus_signature)
                                    (types.FunctionType(
                                nonmethod_func.func_code,
                                nonmethod_func.func_globals,
                                nonmethod_func.func_name,
                                nonmethod_func.func_defaults,
                                nonmethod_func.func_closure)))
                    # Define a creator of a function to call both the
                    # old and new functions, so both the old and new
                    # signals gets sent when the function is called
                    def fixscope(func1, func2):
                        """This function is a scope container to pass
                        func1 and func2 to the "call_both" function
                        outside of its arguments"""
                        def call_both(*args, **kwargs):
                            """This function will emit two D-Bus
                            signals by calling func1 and func2"""
                            func1(*args, **kwargs)
                            func2(*args, **kwargs)
                        return call_both
                    # Create the "call_both" function and add it to
                    # the class
                    attr[attrname] = fixscope(attribute,
                                              new_function)
                # Is this a D-Bus method?
                elif getattr(attribute, "_dbus_is_method", False):
                    # Create a new, but exactly alike, function
                    # object.  Decorate it to be a new D-Bus method
                    # with the alternate D-Bus interface name.  Add it
                    # to the class.
                    attr[attrname] = (dbus.service.method
                                      (alt_interface,
                                       attribute._dbus_in_signature,
                                       attribute._dbus_out_signature)
                                      (types.FunctionType
                                       (attribute.func_code,
                                        attribute.func_globals,
                                        attribute.func_name,
                                        attribute.func_defaults,
                                        attribute.func_closure)))
                # Is this a D-Bus property?
                elif getattr(attribute, "_dbus_is_property", False):
                    # Create a new, but exactly alike, function
                    # object, and decorate it to be a new D-Bus
                    # property with the alternate D-Bus interface
                    # name.  Add it to the class.
                    attr[attrname] = (dbus_service_property
                                      (alt_interface,
                                       attribute._dbus_signature,
                                       attribute._dbus_access,
                                       attribute
                                       ._dbus_get_args_options
                                       ["byte_arrays"])
                                      (types.FunctionType
                                       (attribute.func_code,
                                        attribute.func_globals,
                                        attribute.func_name,
                                        attribute.func_defaults,
                                        attribute.func_closure)))
        return type.__new__(mcs, name, bases, attr)

class ClientDBus(Client, DBusObjectWithProperties):
    """A Client class using D-Bus
    
    Attributes:
    dbus_object_path: dbus.ObjectPath
    bus: dbus.SystemBus()
    """
    
    runtime_expansions = (Client.runtime_expansions
                          + ("dbus_object_path",))
    
    # dbus.service.Object doesn't use super(), so we can't either.
    
    def __init__(self, bus = None, *args, **kwargs):
        self._approvals_pending = 0
        self.bus = bus
        Client.__init__(self, *args, **kwargs)
        # Only now, when this client is initialized, can it show up on
        # the D-Bus
        client_object_name = unicode(self.name).translate(
            {ord("."): ord("_"),
             ord("-"): ord("_")})
        self.dbus_object_path = (dbus.ObjectPath
                                 ("/clients/" + client_object_name))
        DBusObjectWithProperties.__init__(self, self.bus,
                                          self.dbus_object_path)
        
    def notifychangeproperty(transform_func,
                             dbus_name, type_func=lambda x: x,
                             variant_level=1):
        """ Modify a variable so that it's a property which announces
        its changes to DBus.

        transform_fun: Function that takes a value and transforms it
                       to a D-Bus type.
        dbus_name: D-Bus name of the variable
        type_func: Function that transform the value before sending it
                   to the D-Bus.  Default: no transform
        variant_level: D-Bus variant level.  Default: 1
        """
        attrname = "_{0}".format(dbus_name)
        def setter(self, value):
            if hasattr(self, "dbus_object_path"):
                if (not hasattr(self, attrname) or
                    type_func(getattr(self, attrname, None))
                    != type_func(value)):
                    dbus_value = transform_func(type_func(value),
                                                variant_level)
                    self.PropertyChanged(dbus.String(dbus_name),
                                         dbus_value)
            setattr(self, attrname, value)
        
        return property(lambda self: getattr(self, attrname), setter)
    
    
    expires = notifychangeproperty(datetime_to_dbus, "Expires")
    approvals_pending = notifychangeproperty(dbus.Boolean,
                                             "ApprovalPending",
                                             type_func = bool)
    enabled = notifychangeproperty(dbus.Boolean, "Enabled")
    last_enabled = notifychangeproperty(datetime_to_dbus,
                                        "LastEnabled")
    checker = notifychangeproperty(dbus.Boolean, "CheckerRunning",
                                   type_func = lambda checker:
                                       checker is not None)
    last_checked_ok = notifychangeproperty(datetime_to_dbus,
                                           "LastCheckedOK")
    last_approval_request = notifychangeproperty(
        datetime_to_dbus, "LastApprovalRequest")
    approved_by_default = notifychangeproperty(dbus.Boolean,
                                               "ApprovedByDefault")
    approval_delay = notifychangeproperty(dbus.UInt16,
                                          "ApprovalDelay",
                                          type_func =
                                          _timedelta_to_milliseconds)
    approval_duration = notifychangeproperty(
        dbus.UInt16, "ApprovalDuration",
        type_func = _timedelta_to_milliseconds)
    host = notifychangeproperty(dbus.String, "Host")
    timeout = notifychangeproperty(dbus.UInt16, "Timeout",
                                   type_func =
                                   _timedelta_to_milliseconds)
    extended_timeout = notifychangeproperty(
        dbus.UInt16, "ExtendedTimeout",
        type_func = _timedelta_to_milliseconds)
    interval = notifychangeproperty(dbus.UInt16,
                                    "Interval",
                                    type_func =
                                    _timedelta_to_milliseconds)
    checker_command = notifychangeproperty(dbus.String, "Checker")
    
    del notifychangeproperty
    
    def __del__(self, *args, **kwargs):
        try:
            self.remove_from_connection()
        except LookupError:
            pass
        if hasattr(DBusObjectWithProperties, "__del__"):
            DBusObjectWithProperties.__del__(self, *args, **kwargs)
        Client.__del__(self, *args, **kwargs)
    
    def checker_callback(self, pid, condition, command,
                         *args, **kwargs):
        self.checker_callback_tag = None
        self.checker = None
        if os.WIFEXITED(condition):
            exitstatus = os.WEXITSTATUS(condition)
            # Emit D-Bus signal
            self.CheckerCompleted(dbus.Int16(exitstatus),
                                  dbus.Int64(condition),
                                  dbus.String(command))
        else:
            # Emit D-Bus signal
            self.CheckerCompleted(dbus.Int16(-1),
                                  dbus.Int64(condition),
                                  dbus.String(command))
        
        return Client.checker_callback(self, pid, condition, command,
                                       *args, **kwargs)
    
    def start_checker(self, *args, **kwargs):
        old_checker = self.checker
        if self.checker is not None:
            old_checker_pid = self.checker.pid
        else:
            old_checker_pid = None
        r = Client.start_checker(self, *args, **kwargs)
        # Only if new checker process was started
        if (self.checker is not None
            and old_checker_pid != self.checker.pid):
            # Emit D-Bus signal
            self.CheckerStarted(self.current_checker_command)
        return r
    
    def _reset_approved(self):
        self._approved = None
        return False
    
    def approve(self, value=True):
        self.send_changedstate()
        self._approved = value
        gobject.timeout_add(_timedelta_to_milliseconds
                            (self.approval_duration),
                            self._reset_approved)
    
    
    ## D-Bus methods, signals & properties
    _interface = "se.recompile.Mandos.Client"
    
    ## Signals
    
    # CheckerCompleted - signal
    @dbus.service.signal(_interface, signature="nxs")
    def CheckerCompleted(self, exitcode, waitstatus, command):
        "D-Bus signal"
        pass
    
    # CheckerStarted - signal
    @dbus.service.signal(_interface, signature="s")
    def CheckerStarted(self, command):
        "D-Bus signal"
        pass
    
    # PropertyChanged - signal
    @dbus.service.signal(_interface, signature="sv")
    def PropertyChanged(self, property, value):
        "D-Bus signal"
        pass
    
    # GotSecret - signal
    @dbus.service.signal(_interface)
    def GotSecret(self):
        """D-Bus signal
        Is sent after a successful transfer of secret from the Mandos
        server to mandos-client
        """
        pass
    
    # Rejected - signal
    @dbus.service.signal(_interface, signature="s")
    def Rejected(self, reason):
        "D-Bus signal"
        pass
    
    # NeedApproval - signal
    @dbus.service.signal(_interface, signature="tb")
    def NeedApproval(self, timeout, default):
        "D-Bus signal"
        return self.need_approval()
    
    ## Methods
    
    # Approve - method
    @dbus.service.method(_interface, in_signature="b")
    def Approve(self, value):
        self.approve(value)
    
    # CheckedOK - method
    @dbus.service.method(_interface)
    def CheckedOK(self):
        self.checked_ok()
    
    # Enable - method
    @dbus.service.method(_interface)
    def Enable(self):
        "D-Bus method"
        self.enable()
    
    # StartChecker - method
    @dbus.service.method(_interface)
    def StartChecker(self):
        "D-Bus method"
        self.start_checker()
    
    # Disable - method
    @dbus.service.method(_interface)
    def Disable(self):
        "D-Bus method"
        self.disable()
    
    # StopChecker - method
    @dbus.service.method(_interface)
    def StopChecker(self):
        self.stop_checker()
    
    ## Properties
    
    # ApprovalPending - property
    @dbus_service_property(_interface, signature="b", access="read")
    def ApprovalPending_dbus_property(self):
        return dbus.Boolean(bool(self.approvals_pending))
    
    # ApprovedByDefault - property
    @dbus_service_property(_interface, signature="b",
                           access="readwrite")
    def ApprovedByDefault_dbus_property(self, value=None):
        if value is None:       # get
            return dbus.Boolean(self.approved_by_default)
        self.approved_by_default = bool(value)
    
    # ApprovalDelay - property
    @dbus_service_property(_interface, signature="t",
                           access="readwrite")
    def ApprovalDelay_dbus_property(self, value=None):
        if value is None:       # get
            return dbus.UInt64(self.approval_delay_milliseconds())
        self.approval_delay = datetime.timedelta(0, 0, 0, value)
    
    # ApprovalDuration - property
    @dbus_service_property(_interface, signature="t",
                           access="readwrite")
    def ApprovalDuration_dbus_property(self, value=None):
        if value is None:       # get
            return dbus.UInt64(_timedelta_to_milliseconds(
                    self.approval_duration))
        self.approval_duration = datetime.timedelta(0, 0, 0, value)
    
    # Name - property
    @dbus_service_property(_interface, signature="s", access="read")
    def Name_dbus_property(self):
        return dbus.String(self.name)
    
    # Fingerprint - property
    @dbus_service_property(_interface, signature="s", access="read")
    def Fingerprint_dbus_property(self):
        return dbus.String(self.fingerprint)
    
    # Host - property
    @dbus_service_property(_interface, signature="s",
                           access="readwrite")
    def Host_dbus_property(self, value=None):
        if value is None:       # get
            return dbus.String(self.host)
        self.host = value
    
    # Created - property
    @dbus_service_property(_interface, signature="s", access="read")
    def Created_dbus_property(self):
        return dbus.String(datetime_to_dbus(self.created))
    
    # LastEnabled - property
    @dbus_service_property(_interface, signature="s", access="read")
    def LastEnabled_dbus_property(self):
        return datetime_to_dbus(self.last_enabled)
    
    # Enabled - property
    @dbus_service_property(_interface, signature="b",
                           access="readwrite")
    def Enabled_dbus_property(self, value=None):
        if value is None:       # get
            return dbus.Boolean(self.enabled)
        if value:
            self.enable()
        else:
            self.disable()
    
    # LastCheckedOK - property
    @dbus_service_property(_interface, signature="s",
                           access="readwrite")
    def LastCheckedOK_dbus_property(self, value=None):
        if value is not None:
            self.checked_ok()
            return
        return datetime_to_dbus(self.last_checked_ok)
    
    # Expires - property
    @dbus_service_property(_interface, signature="s", access="read")
    def Expires_dbus_property(self):
        return datetime_to_dbus(self.expires)
    
    # LastApprovalRequest - property
    @dbus_service_property(_interface, signature="s", access="read")
    def LastApprovalRequest_dbus_property(self):
        return datetime_to_dbus(self.last_approval_request)
    
    # Timeout - property
    @dbus_service_property(_interface, signature="t",
                           access="readwrite")
    def Timeout_dbus_property(self, value=None):
        if value is None:       # get
            return dbus.UInt64(self.timeout_milliseconds())
        self.timeout = datetime.timedelta(0, 0, 0, value)
        if getattr(self, "disable_initiator_tag", None) is None:
            return
        # Reschedule timeout
        gobject.source_remove(self.disable_initiator_tag)
        self.disable_initiator_tag = None
        self.expires = None
        time_to_die = (self.
                       _timedelta_to_milliseconds((self
                                                   .last_checked_ok
                                                   + self.timeout)
                                                  - datetime.datetime
                                                  .utcnow()))
        if time_to_die <= 0:
            # The timeout has passed
            self.disable()
        else:
            self.expires = (datetime.datetime.utcnow()
                            + datetime.timedelta(milliseconds =
                                                 time_to_die))
            self.disable_initiator_tag = (gobject.timeout_add
                                          (time_to_die, self.disable))
    
    # ExtendedTimeout - property
    @dbus_service_property(_interface, signature="t",
                           access="readwrite")
    def ExtendedTimeout_dbus_property(self, value=None):
        if value is None:       # get
            return dbus.UInt64(self.extended_timeout_milliseconds())
        self.extended_timeout = datetime.timedelta(0, 0, 0, value)
    
    # Interval - property
    @dbus_service_property(_interface, signature="t",
                           access="readwrite")
    def Interval_dbus_property(self, value=None):
        if value is None:       # get
            return dbus.UInt64(self.interval_milliseconds())
        self.interval = datetime.timedelta(0, 0, 0, value)
        if getattr(self, "checker_initiator_tag", None) is None:
            return
        # Reschedule checker run
        gobject.source_remove(self.checker_initiator_tag)
        self.checker_initiator_tag = (gobject.timeout_add
                                      (value, self.start_checker))
        self.start_checker()    # Start one now, too
    
    # Checker - property
    @dbus_service_property(_interface, signature="s",
                           access="readwrite")
    def Checker_dbus_property(self, value=None):
        if value is None:       # get
            return dbus.String(self.checker_command)
        self.checker_command = value
    
    # CheckerRunning - property
    @dbus_service_property(_interface, signature="b",
                           access="readwrite")
    def CheckerRunning_dbus_property(self, value=None):
        if value is None:       # get
            return dbus.Boolean(self.checker is not None)
        if value:
            self.start_checker()
        else:
            self.stop_checker()
    
    # ObjectPath - property
    @dbus_service_property(_interface, signature="o", access="read")
    def ObjectPath_dbus_property(self):
        return self.dbus_object_path # is already a dbus.ObjectPath
    
    # Secret = property
    @dbus_service_property(_interface, signature="ay",
                           access="write", byte_arrays=True)
    def Secret_dbus_property(self, value):
        self.secret = str(value)
    
    del _interface


class ProxyClient(object):
    def __init__(self, child_pipe, fpr, address):
        self._pipe = child_pipe
        self._pipe.send(('init', fpr, address))
        if not self._pipe.recv():
            raise KeyError()
    
    def __getattribute__(self, name):
        if(name == '_pipe'):
            return super(ProxyClient, self).__getattribute__(name)
        self._pipe.send(('getattr', name))
        data = self._pipe.recv()
        if data[0] == 'data':
            return data[1]
        if data[0] == 'function':
            def func(*args, **kwargs):
                self._pipe.send(('funcall', name, args, kwargs))
                return self._pipe.recv()[1]
            return func
    
    def __setattr__(self, name, value):
        if(name == '_pipe'):
            return super(ProxyClient, self).__setattr__(name, value)
        self._pipe.send(('setattr', name, value))

class ClientDBusTransitional(ClientDBus):
    __metaclass__ = AlternateDBusNamesMetaclass

class ClientHandler(socketserver.BaseRequestHandler, object):
    """A class to handle client connections.
    
    Instantiated once for each connection to handle it.
    Note: This will run in its own forked process."""
    
    def handle(self):
        with contextlib.closing(self.server.child_pipe) as child_pipe:
            logger.info("TCP connection from: %s",
                        unicode(self.client_address))
            logger.debug("Pipe FD: %d",
                         self.server.child_pipe.fileno())
            
            session = (gnutls.connection
                       .ClientSession(self.request,
                                      gnutls.connection
                                      .X509Credentials()))
            
            # Note: gnutls.connection.X509Credentials is really a
            # generic GnuTLS certificate credentials object so long as
            # no X.509 keys are added to it.  Therefore, we can use it
            # here despite using OpenPGP certificates.
            
            #priority = ':'.join(("NONE", "+VERS-TLS1.1",
            #                      "+AES-256-CBC", "+SHA1",
            #                      "+COMP-NULL", "+CTYPE-OPENPGP",
            #                      "+DHE-DSS"))
            # Use a fallback default, since this MUST be set.
            priority = self.server.gnutls_priority
            if priority is None:
                priority = "NORMAL"
            (gnutls.library.functions
             .gnutls_priority_set_direct(session._c_object,
                                         priority, None))
            
            # Start communication using the Mandos protocol
            # Get protocol number
            line = self.request.makefile().readline()
            logger.debug("Protocol version: %r", line)
            try:
                if int(line.strip().split()[0]) > 1:
                    raise RuntimeError
            except (ValueError, IndexError, RuntimeError) as error:
                logger.error("Unknown protocol version: %s", error)
                return
            
            # Start GnuTLS connection
            try:
                session.handshake()
            except gnutls.errors.GNUTLSError as error:
                logger.warning("Handshake failed: %s", error)
                # Do not run session.bye() here: the session is not
                # established.  Just abandon the request.
                return
            logger.debug("Handshake succeeded")
            
            approval_required = False
            try:
                try:
                    fpr = self.fingerprint(self.peer_certificate
                                           (session))
                except (TypeError,
                        gnutls.errors.GNUTLSError) as error:
                    logger.warning("Bad certificate: %s", error)
                    return
                logger.debug("Fingerprint: %s", fpr)
                
                try:
                    client = ProxyClient(child_pipe, fpr,
                                         self.client_address)
                except KeyError:
                    return
                
                if client.approval_delay:
                    delay = client.approval_delay
                    client.approvals_pending += 1
                    approval_required = True
                
                while True:
                    if not client.enabled:
                        logger.info("Client %s is disabled",
                                       client.name)
                        if self.server.use_dbus:
                            # Emit D-Bus signal
                            client.Rejected("Disabled")
                        return
                    
                    if client._approved or not client.approval_delay:
                        #We are approved or approval is disabled
                        break
                    elif client._approved is None:
                        logger.info("Client %s needs approval",
                                    client.name)
                        if self.server.use_dbus:
                            # Emit D-Bus signal
                            client.NeedApproval(
                                client.approval_delay_milliseconds(),
                                client.approved_by_default)
                    else:
                        logger.warning("Client %s was not approved",
                                       client.name)
                        if self.server.use_dbus:
                            # Emit D-Bus signal
                            client.Rejected("Denied")
                        return
                    
                    #wait until timeout or approved
                    #x = float(client
                    #          ._timedelta_to_milliseconds(delay))
                    time = datetime.datetime.now()
                    client.changedstate.acquire()
                    (client.changedstate.wait
                     (float(client._timedelta_to_milliseconds(delay)
                            / 1000)))
                    client.changedstate.release()
                    time2 = datetime.datetime.now()
                    if (time2 - time) >= delay:
                        if not client.approved_by_default:
                            logger.warning("Client %s timed out while"
                                           " waiting for approval",
                                           client.name)
                            if self.server.use_dbus:
                                # Emit D-Bus signal
                                client.Rejected("Approval timed out")
                            return
                        else:
                            break
                    else:
                        delay -= time2 - time
                
                sent_size = 0
                while sent_size < len(client.secret):
                    try:
                        sent = session.send(client.secret[sent_size:])
                    except gnutls.errors.GNUTLSError as error:
                        logger.warning("gnutls send failed")
                        return
                    logger.debug("Sent: %d, remaining: %d",
                                 sent, len(client.secret)
                                 - (sent_size + sent))
                    sent_size += sent
                
                logger.info("Sending secret to %s", client.name)
                # bump the timeout as if seen
                client.checked_ok(client.extended_timeout)
                if self.server.use_dbus:
                    # Emit D-Bus signal
                    client.GotSecret()
            
            finally:
                if approval_required:
                    client.approvals_pending -= 1
                try:
                    session.bye()
                except gnutls.errors.GNUTLSError as error:
                    logger.warning("GnuTLS bye failed")
    
    @staticmethod
    def peer_certificate(session):
        "Return the peer's OpenPGP certificate as a bytestring"
        # If not an OpenPGP certificate...
        if (gnutls.library.functions
            .gnutls_certificate_type_get(session._c_object)
            != gnutls.library.constants.GNUTLS_CRT_OPENPGP):
            # ...do the normal thing
            return session.peer_certificate
        list_size = ctypes.c_uint(1)
        cert_list = (gnutls.library.functions
                     .gnutls_certificate_get_peers
                     (session._c_object, ctypes.byref(list_size)))
        if not bool(cert_list) and list_size.value != 0:
            raise gnutls.errors.GNUTLSError("error getting peer"
                                            " certificate")
        if list_size.value == 0:
            return None
        cert = cert_list[0]
        return ctypes.string_at(cert.data, cert.size)
    
    @staticmethod
    def fingerprint(openpgp):
        "Convert an OpenPGP bytestring to a hexdigit fingerprint"
        # New GnuTLS "datum" with the OpenPGP public key
        datum = (gnutls.library.types
                 .gnutls_datum_t(ctypes.cast(ctypes.c_char_p(openpgp),
                                             ctypes.POINTER
                                             (ctypes.c_ubyte)),
                                 ctypes.c_uint(len(openpgp))))
        # New empty GnuTLS certificate
        crt = gnutls.library.types.gnutls_openpgp_crt_t()
        (gnutls.library.functions
         .gnutls_openpgp_crt_init(ctypes.byref(crt)))
        # Import the OpenPGP public key into the certificate
        (gnutls.library.functions
         .gnutls_openpgp_crt_import(crt, ctypes.byref(datum),
                                    gnutls.library.constants
                                    .GNUTLS_OPENPGP_FMT_RAW))
        # Verify the self signature in the key
        crtverify = ctypes.c_uint()
        (gnutls.library.functions
         .gnutls_openpgp_crt_verify_self(crt, 0,
                                         ctypes.byref(crtverify)))
        if crtverify.value != 0:
            gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
            raise (gnutls.errors.CertificateSecurityError
                   ("Verify failed"))
        # New buffer for the fingerprint
        buf = ctypes.create_string_buffer(20)
        buf_len = ctypes.c_size_t()
        # Get the fingerprint from the certificate into the buffer
        (gnutls.library.functions
         .gnutls_openpgp_crt_get_fingerprint(crt, ctypes.byref(buf),
                                             ctypes.byref(buf_len)))
        # Deinit the certificate
        gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
        # Convert the buffer to a Python bytestring
        fpr = ctypes.string_at(buf, buf_len.value)
        # Convert the bytestring to hexadecimal notation
        hex_fpr = ''.join("%02X" % ord(char) for char in fpr)
        return hex_fpr


class MultiprocessingMixIn(object):
    """Like socketserver.ThreadingMixIn, but with multiprocessing"""
    def sub_process_main(self, request, address):
        try:
            self.finish_request(request, address)
        except:
            self.handle_error(request, address)
        self.close_request(request)
            
    def process_request(self, request, address):
        """Start a new process to process the request."""
        multiprocessing.Process(target = self.sub_process_main,
                                args = (request, address)).start()


class MultiprocessingMixInWithPipe(MultiprocessingMixIn, object):
    """ adds a pipe to the MixIn """
    def process_request(self, request, client_address):
        """Overrides and wraps the original process_request().
        
        This function creates a new pipe in self.pipe
        """
        parent_pipe, self.child_pipe = multiprocessing.Pipe()
        
        super(MultiprocessingMixInWithPipe,
              self).process_request(request, client_address)
        self.child_pipe.close()
        self.add_pipe(parent_pipe)
    
    def add_pipe(self, parent_pipe):
        """Dummy function; override as necessary"""
        raise NotImplementedError


class IPv6_TCPServer(MultiprocessingMixInWithPipe,
                     socketserver.TCPServer, object):
    """IPv6-capable TCP server.  Accepts 'None' as address and/or port
    
    Attributes:
        enabled:        Boolean; whether this server is activated yet
        interface:      None or a network interface name (string)
        use_ipv6:       Boolean; to use IPv6 or not
    """
    def __init__(self, server_address, RequestHandlerClass,
                 interface=None, use_ipv6=True):
        self.interface = interface
        if use_ipv6:
            self.address_family = socket.AF_INET6
        socketserver.TCPServer.__init__(self, server_address,
                                        RequestHandlerClass)
    def server_bind(self):
        """This overrides the normal server_bind() function
        to bind to an interface if one was specified, and also NOT to
        bind to an address or port if they were not specified."""
        if self.interface is not None:
            if SO_BINDTODEVICE is None:
                logger.error("SO_BINDTODEVICE does not exist;"
                             " cannot bind to interface %s",
                             self.interface)
            else:
                try:
                    self.socket.setsockopt(socket.SOL_SOCKET,
                                           SO_BINDTODEVICE,
                                           str(self.interface
                                               + '\0'))
                except socket.error as error:
                    if error[0] == errno.EPERM:
                        logger.error("No permission to"
                                     " bind to interface %s",
                                     self.interface)
                    elif error[0] == errno.ENOPROTOOPT:
                        logger.error("SO_BINDTODEVICE not available;"
                                     " cannot bind to interface %s",
                                     self.interface)
                    else:
                        raise
        # Only bind(2) the socket if we really need to.
        if self.server_address[0] or self.server_address[1]:
            if not self.server_address[0]:
                if self.address_family == socket.AF_INET6:
                    any_address = "::" # in6addr_any
                else:
                    any_address = socket.INADDR_ANY
                self.server_address = (any_address,
                                       self.server_address[1])
            elif not self.server_address[1]:
                self.server_address = (self.server_address[0],
                                       0)
#                 if self.interface:
#                     self.server_address = (self.server_address[0],
#                                            0, # port
#                                            0, # flowinfo
#                                            if_nametoindex
#                                            (self.interface))
            return socketserver.TCPServer.server_bind(self)


class MandosServer(IPv6_TCPServer):
    """Mandos server.
    
    Attributes:
        clients:        set of Client objects
        gnutls_priority GnuTLS priority string
        use_dbus:       Boolean; to emit D-Bus signals or not
    
    Assumes a gobject.MainLoop event loop.
    """
    def __init__(self, server_address, RequestHandlerClass,
                 interface=None, use_ipv6=True, clients=None,
                 gnutls_priority=None, use_dbus=True):
        self.enabled = False
        self.clients = clients
        if self.clients is None:
            self.clients = set()
        self.use_dbus = use_dbus
        self.gnutls_priority = gnutls_priority
        IPv6_TCPServer.__init__(self, server_address,
                                RequestHandlerClass,
                                interface = interface,
                                use_ipv6 = use_ipv6)
    def server_activate(self):
        if self.enabled:
            return socketserver.TCPServer.server_activate(self)
    def enable(self):
        self.enabled = True
    def add_pipe(self, parent_pipe):
        # Call "handle_ipc" for both data and EOF events
        gobject.io_add_watch(parent_pipe.fileno(),
                             gobject.IO_IN | gobject.IO_HUP,
                             functools.partial(self.handle_ipc,
                                               parent_pipe =
                                               parent_pipe))
        
    def handle_ipc(self, source, condition, parent_pipe=None,
                   client_object=None):
        condition_names = {
            gobject.IO_IN: "IN",   # There is data to read.
            gobject.IO_OUT: "OUT", # Data can be written (without
                                    # blocking).
            gobject.IO_PRI: "PRI", # There is urgent data to read.
            gobject.IO_ERR: "ERR", # Error condition.
            gobject.IO_HUP: "HUP"  # Hung up (the connection has been
                                    # broken, usually for pipes and
                                    # sockets).
            }
        conditions_string = ' | '.join(name
                                       for cond, name in
                                       condition_names.iteritems()
                                       if cond & condition)
        # error or the other end of multiprocessing.Pipe has closed
        if condition & (gobject.IO_ERR | condition & gobject.IO_HUP):
            return False
        
        # Read a request from the child
        request = parent_pipe.recv()
        command = request[0]
        
        if command == 'init':
            fpr = request[1]
            address = request[2]
            
            for c in self.clients:
                if c.fingerprint == fpr:
                    client = c
                    break
            else:
                logger.info("Client not found for fingerprint: %s, ad"
                            "dress: %s", fpr, address)
                if self.use_dbus:
                    # Emit D-Bus signal
                    mandos_dbus_service.ClientNotFound(fpr,
                                                       address[0])
                parent_pipe.send(False)
                return False
            
            gobject.io_add_watch(parent_pipe.fileno(),
                                 gobject.IO_IN | gobject.IO_HUP,
                                 functools.partial(self.handle_ipc,
                                                   parent_pipe =
                                                   parent_pipe,
                                                   client_object =
                                                   client))
            parent_pipe.send(True)
            # remove the old hook in favor of the new above hook on
            # same fileno
            return False
        if command == 'funcall':
            funcname = request[1]
            args = request[2]
            kwargs = request[3]
            
            parent_pipe.send(('data', getattr(client_object,
                                              funcname)(*args,
                                                         **kwargs)))
        
        if command == 'getattr':
            attrname = request[1]
            if callable(client_object.__getattribute__(attrname)):
                parent_pipe.send(('function',))
            else:
                parent_pipe.send(('data', client_object
                                  .__getattribute__(attrname)))
        
        if command == 'setattr':
            attrname = request[1]
            value = request[2]
            setattr(client_object, attrname, value)
        
        return True


def string_to_delta(interval):
    """Parse a string and return a datetime.timedelta
    
    >>> string_to_delta('7d')
    datetime.timedelta(7)
    >>> string_to_delta('60s')
    datetime.timedelta(0, 60)
    >>> string_to_delta('60m')
    datetime.timedelta(0, 3600)
    >>> string_to_delta('24h')
    datetime.timedelta(1)
    >>> string_to_delta('1w')
    datetime.timedelta(7)
    >>> string_to_delta('5m 30s')
    datetime.timedelta(0, 330)
    """
    timevalue = datetime.timedelta(0)
    for s in interval.split():
        try:
            suffix = unicode(s[-1])
            value = int(s[:-1])
            if suffix == "d":
                delta = datetime.timedelta(value)
            elif suffix == "s":
                delta = datetime.timedelta(0, value)
            elif suffix == "m":
                delta = datetime.timedelta(0, 0, 0, 0, value)
            elif suffix == "h":
                delta = datetime.timedelta(0, 0, 0, 0, 0, value)
            elif suffix == "w":
                delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
            else:
                raise ValueError("Unknown suffix %r" % suffix)
        except (ValueError, IndexError) as e:
            raise ValueError(*(e.args))
        timevalue += delta
    return timevalue


def if_nametoindex(interface):
    """Call the C function if_nametoindex(), or equivalent
    
    Note: This function cannot accept a unicode string."""
    global if_nametoindex
    try:
        if_nametoindex = (ctypes.cdll.LoadLibrary
                          (ctypes.util.find_library("c"))
                          .if_nametoindex)
    except (OSError, AttributeError):
        logger.warning("Doing if_nametoindex the hard way")
        def if_nametoindex(interface):
            "Get an interface index the hard way, i.e. using fcntl()"
            SIOCGIFINDEX = 0x8933  # From /usr/include/linux/sockios.h
            with contextlib.closing(socket.socket()) as s:
                ifreq = fcntl.ioctl(s, SIOCGIFINDEX,
                                    struct.pack(str("16s16x"),
                                                interface))
            interface_index = struct.unpack(str("I"),
                                            ifreq[16:20])[0]
            return interface_index
    return if_nametoindex(interface)


def daemon(nochdir = False, noclose = False):
    """See daemon(3).  Standard BSD Unix function.
    
    This should really exist as os.daemon, but it doesn't (yet)."""
    if os.fork():
        sys.exit()
    os.setsid()
    if not nochdir:
        os.chdir("/")
    if os.fork():
        sys.exit()
    if not noclose:
        # Close all standard open file descriptors
        null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
        if not stat.S_ISCHR(os.fstat(null).st_mode):
            raise OSError(errno.ENODEV,
                          "%s not a character device"
                          % os.path.devnull)
        os.dup2(null, sys.stdin.fileno())
        os.dup2(null, sys.stdout.fileno())
        os.dup2(null, sys.stderr.fileno())
        if null > 2:
            os.close(null)


def main():
    
    ##################################################################
    # Parsing of options, both command line and config file
    
    parser = argparse.ArgumentParser()
    parser.add_argument("-v", "--version", action="version",
                        version = "%%(prog)s %s" % version,
                        help="show version number and exit")
    parser.add_argument("-i", "--interface", metavar="IF",
                        help="Bind to interface IF")
    parser.add_argument("-a", "--address",
                        help="Address to listen for requests on")
    parser.add_argument("-p", "--port", type=int,
                        help="Port number to receive requests on")
    parser.add_argument("--check", action="store_true",
                        help="Run self-test")
    parser.add_argument("--debug", action="store_true",
                        help="Debug mode; run in foreground and log"
                        " to terminal")
    parser.add_argument("--debuglevel", metavar="LEVEL",
                        help="Debug level for stdout output")
    parser.add_argument("--priority", help="GnuTLS"
                        " priority string (see GnuTLS documentation)")
    parser.add_argument("--servicename",
                        metavar="NAME", help="Zeroconf service name")
    parser.add_argument("--configdir",
                        default="/etc/mandos", metavar="DIR",
                        help="Directory to search for configuration"
                        " files")
    parser.add_argument("--no-dbus", action="store_false",
                        dest="use_dbus", help="Do not provide D-Bus"
                        " system bus interface")
    parser.add_argument("--no-ipv6", action="store_false",
                        dest="use_ipv6", help="Do not use IPv6")
    options = parser.parse_args()
    
    if options.check:
        import doctest
        doctest.testmod()
        sys.exit()
    
    # Default values for config file for server-global settings
    server_defaults = { "interface": "",
                        "address": "",
                        "port": "",
                        "debug": "False",
                        "priority":
                        "SECURE256:!CTYPE-X.509:+CTYPE-OPENPGP",
                        "servicename": "Mandos",
                        "use_dbus": "True",
                        "use_ipv6": "True",
                        "debuglevel": "",
                        }
    
    # Parse config file for server-global settings
    server_config = configparser.SafeConfigParser(server_defaults)
    del server_defaults
    server_config.read(os.path.join(options.configdir,
                                    "mandos.conf"))
    # Convert the SafeConfigParser object to a dict
    server_settings = server_config.defaults()
    # Use the appropriate methods on the non-string config options
    for option in ("debug", "use_dbus", "use_ipv6"):
        server_settings[option] = server_config.getboolean("DEFAULT",
                                                           option)
    if server_settings["port"]:
        server_settings["port"] = server_config.getint("DEFAULT",
                                                       "port")
    del server_config
    
    # Override the settings from the config file with command line
    # options, if set.
    for option in ("interface", "address", "port", "debug",
                   "priority", "servicename", "configdir",
                   "use_dbus", "use_ipv6", "debuglevel"):
        value = getattr(options, option)
        if value is not None:
            server_settings[option] = value
    del options
    # Force all strings to be unicode
    for option in server_settings.keys():
        if type(server_settings[option]) is str:
            server_settings[option] = unicode(server_settings[option])
    # Now we have our good server settings in "server_settings"
    
    ##################################################################
    
    # For convenience
    debug = server_settings["debug"]
    debuglevel = server_settings["debuglevel"]
    use_dbus = server_settings["use_dbus"]
    use_ipv6 = server_settings["use_ipv6"]
    
    if server_settings["servicename"] != "Mandos":
        syslogger.setFormatter(logging.Formatter
                               ('Mandos (%s) [%%(process)d]:'
                                ' %%(levelname)s: %%(message)s'
                                % server_settings["servicename"]))
    
    # Parse config file with clients
    client_defaults = { "timeout": "5m",
                        "extended_timeout": "15m",
                        "interval": "2m",
                        "checker": "fping -q -- %%(host)s",
                        "host": "",
                        "approval_delay": "0s",
                        "approval_duration": "1s",
                        }
    client_config = configparser.SafeConfigParser(client_defaults)
    client_config.read(os.path.join(server_settings["configdir"],
                                    "clients.conf"))
    
    global mandos_dbus_service
    mandos_dbus_service = None
    
    tcp_server = MandosServer((server_settings["address"],
                               server_settings["port"]),
                              ClientHandler,
                              interface=(server_settings["interface"]
                                         or None),
                              use_ipv6=use_ipv6,
                              gnutls_priority=
                              server_settings["priority"],
                              use_dbus=use_dbus)
    if not debug:
        pidfilename = "/var/run/mandos.pid"
        try:
            pidfile = open(pidfilename, "w")
        except IOError:
            logger.error("Could not open file %r", pidfilename)
    
    try:
        uid = pwd.getpwnam("_mandos").pw_uid
        gid = pwd.getpwnam("_mandos").pw_gid
    except KeyError:
        try:
            uid = pwd.getpwnam("mandos").pw_uid
            gid = pwd.getpwnam("mandos").pw_gid
        except KeyError:
            try:
                uid = pwd.getpwnam("nobody").pw_uid
                gid = pwd.getpwnam("nobody").pw_gid
            except KeyError:
                uid = 65534
                gid = 65534
    try:
        os.setgid(gid)
        os.setuid(uid)
    except OSError as error:
        if error[0] != errno.EPERM:
            raise error
    
    if not debug and not debuglevel:
        syslogger.setLevel(logging.WARNING)
        console.setLevel(logging.WARNING)
    if debuglevel:
        level = getattr(logging, debuglevel.upper())
        syslogger.setLevel(level)
        console.setLevel(level)
    
    if debug:
        # Enable all possible GnuTLS debugging
        
        # "Use a log level over 10 to enable all debugging options."
        # - GnuTLS manual
        gnutls.library.functions.gnutls_global_set_log_level(11)
        
        @gnutls.library.types.gnutls_log_func
        def debug_gnutls(level, string):
            logger.debug("GnuTLS: %s", string[:-1])
        
        (gnutls.library.functions
         .gnutls_global_set_log_function(debug_gnutls))
        
        # Redirect stdin so all checkers get /dev/null
        null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
        os.dup2(null, sys.stdin.fileno())
        if null > 2:
            os.close(null)
    else:
        # No console logging
        logger.removeHandler(console)
    
    # Need to fork before connecting to D-Bus
    if not debug:
        # Close all input and output, do double fork, etc.
        daemon()
    
    global main_loop
    # From the Avahi example code
    DBusGMainLoop(set_as_default=True )
    main_loop = gobject.MainLoop()
    bus = dbus.SystemBus()
    # End of Avahi example code
    if use_dbus:
        try:
            bus_name = dbus.service.BusName("se.recompile.Mandos",
                                            bus, do_not_queue=True)
            old_bus_name = (dbus.service.BusName
                            ("se.bsnet.fukt.Mandos", bus,
                             do_not_queue=True))
        except dbus.exceptions.NameExistsException as e:
            logger.error(unicode(e) + ", disabling D-Bus")
            use_dbus = False
            server_settings["use_dbus"] = False
            tcp_server.use_dbus = False
    protocol = avahi.PROTO_INET6 if use_ipv6 else avahi.PROTO_INET
    service = AvahiService(name = server_settings["servicename"],
                           servicetype = "_mandos._tcp",
                           protocol = protocol, bus = bus)
    if server_settings["interface"]:
        service.interface = (if_nametoindex
                             (str(server_settings["interface"])))
    
    global multiprocessing_manager
    multiprocessing_manager = multiprocessing.Manager()
    
    client_class = Client
    if use_dbus:
        client_class = functools.partial(ClientDBusTransitional,
                                         bus = bus)
    def client_config_items(config, section):
        special_settings = {
            "approved_by_default":
                lambda: config.getboolean(section,
                                          "approved_by_default"),
            }
        for name, value in config.items(section):
            try:
                yield (name, special_settings[name]())
            except KeyError:
                yield (name, value)
    
    tcp_server.clients.update(set(
            client_class(name = section,
                         config= dict(client_config_items(
                        client_config, section)))
            for section in client_config.sections()))
    if not tcp_server.clients:
        logger.warning("No clients defined")
        
    if not debug:
        try:
            with pidfile:
                pid = os.getpid()
                pidfile.write(str(pid) + "\n".encode("utf-8"))
            del pidfile
        except IOError:
            logger.error("Could not write to file %r with PID %d",
                         pidfilename, pid)
        except NameError:
            # "pidfile" was never created
            pass
        del pidfilename
        
        signal.signal(signal.SIGINT, signal.SIG_IGN)
    
    signal.signal(signal.SIGHUP, lambda signum, frame: sys.exit())
    signal.signal(signal.SIGTERM, lambda signum, frame: sys.exit())
    
    if use_dbus:
        class MandosDBusService(dbus.service.Object):
            """A D-Bus proxy object"""
            def __init__(self):
                dbus.service.Object.__init__(self, bus, "/")
            _interface = "se.recompile.Mandos"
            
            @dbus.service.signal(_interface, signature="o")
            def ClientAdded(self, objpath):
                "D-Bus signal"
                pass
            
            @dbus.service.signal(_interface, signature="ss")
            def ClientNotFound(self, fingerprint, address):
                "D-Bus signal"
                pass
            
            @dbus.service.signal(_interface, signature="os")
            def ClientRemoved(self, objpath, name):
                "D-Bus signal"
                pass
            
            @dbus.service.method(_interface, out_signature="ao")
            def GetAllClients(self):
                "D-Bus method"
                return dbus.Array(c.dbus_object_path
                                  for c in tcp_server.clients)
            
            @dbus.service.method(_interface,
                                 out_signature="a{oa{sv}}")
            def GetAllClientsWithProperties(self):
                "D-Bus method"
                return dbus.Dictionary(
                    ((c.dbus_object_path, c.GetAll(""))
                     for c in tcp_server.clients),
                    signature="oa{sv}")
            
            @dbus.service.method(_interface, in_signature="o")
            def RemoveClient(self, object_path):
                "D-Bus method"
                for c in tcp_server.clients:
                    if c.dbus_object_path == object_path:
                        tcp_server.clients.remove(c)
                        c.remove_from_connection()
                        # Don't signal anything except ClientRemoved
                        c.disable(quiet=True)
                        # Emit D-Bus signal
                        self.ClientRemoved(object_path, c.name)
                        return
                raise KeyError(object_path)
            
            del _interface
        
        class MandosDBusServiceTransitional(MandosDBusService):
            __metaclass__ = AlternateDBusNamesMetaclass
        mandos_dbus_service = MandosDBusServiceTransitional()
    
    def cleanup():
        "Cleanup function; run on exit"
        service.cleanup()
        
        while tcp_server.clients:
            client = tcp_server.clients.pop()
            if use_dbus:
                client.remove_from_connection()
            client.disable_hook = None
            # Don't signal anything except ClientRemoved
            client.disable(quiet=True)
            if use_dbus:
                # Emit D-Bus signal
                mandos_dbus_service.ClientRemoved(client
                                                  .dbus_object_path,
                                                  client.name)
    
    atexit.register(cleanup)
    
    for client in tcp_server.clients:
        if use_dbus:
            # Emit D-Bus signal
            mandos_dbus_service.ClientAdded(client.dbus_object_path)
        client.enable()
    
    tcp_server.enable()
    tcp_server.server_activate()
    
    # Find out what port we got
    service.port = tcp_server.socket.getsockname()[1]
    if use_ipv6:
        logger.info("Now listening on address %r, port %d,"
                    " flowinfo %d, scope_id %d"
                    % tcp_server.socket.getsockname())
    else:                       # IPv4
        logger.info("Now listening on address %r, port %d"
                    % tcp_server.socket.getsockname())
    
    #service.interface = tcp_server.socket.getsockname()[3]
    
    try:
        # From the Avahi example code
        try:
            service.activate()
        except dbus.exceptions.DBusException as error:
            logger.critical("DBusException: %s", error)
            cleanup()
            sys.exit(1)
        # End of Avahi example code
        
        gobject.io_add_watch(tcp_server.fileno(), gobject.IO_IN,
                             lambda *args, **kwargs:
                             (tcp_server.handle_request
                              (*args[2:], **kwargs) or True))
        
        logger.debug("Starting main loop")
        main_loop.run()
    except AvahiError as error:
        logger.critical("AvahiError: %s", error)
        cleanup()
        sys.exit(1)
    except KeyboardInterrupt:
        if debug:
            print("", file=sys.stderr)
        logger.debug("Server received KeyboardInterrupt")
    logger.debug("Server exiting")
    # Must run before the D-Bus bus name gets deregistered
    cleanup()


if __name__ == '__main__':
    main()