This file is indexed.

/usr/bin/irkerd is in irker 2.12+dfsg-1.

This file is owned by root:root, with mode 0o755.

The actual contents of the file can be viewed below.

   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
#! /usr/bin/python
"""
irkerd - a simple IRC multiplexer daemon

Listens for JSON objects of the form {'to':<irc-url>, 'privmsg':<text>}
and relays messages to IRC channels. Each request must be followed by
a newline.

The <text> must be a string.  The value of the 'to' attribute can be a
string containing an IRC URL (e.g. 'irc://chat.freenet.net/botwar') or
a list of such strings; in the latter case the message is broadcast to
all listed channels.  Note that the channel portion of the URL need
*not* have a leading '#' unless the channel name itself does.

Design and code by Eric S. Raymond <esr@thyrsus.com>. See the project
resource page at <http://www.catb.org/~esr/irker/>.

Requires Python 2.7, or:
* 2.6 with the argparse package installed.
"""

from __future__ import unicode_literals
from __future__ import with_statement

# These things might need tuning

HOST = "localhost"
PORT = 6659

XMIT_TTL = (3 * 60 * 60)	# Time to live, seconds from last transmit
PING_TTL = (15 * 60)		# Time to live, seconds from last PING
HANDSHAKE_TTL = 60		# Time to live, seconds from nick transmit
CHANNEL_TTL = (3 * 60 * 60)	# Time to live, seconds from last transmit
DISCONNECT_TTL = (24 * 60 * 60)	# Time to live, seconds from last connect
UNSEEN_TTL = 60			# Time to live, seconds since first request
CHANNEL_MAX = 18		# Max channels open per socket (default)
ANTI_FLOOD_DELAY = 1.0		# Anti-flood delay after transmissions, seconds
ANTI_BUZZ_DELAY = 0.09		# Anti-buzz delay after queue-empty check
CONNECTION_MAX = 200		# To avoid hitting a thread limit

# No user-serviceable parts below this line

version = "2.12"

import argparse
import logging
import logging.handlers
import json
import os
import os.path
try:  # Python 3
    import queue
except ImportError:  # Python 2
    import Queue as queue
import random
import re
import select
import signal
import socket
try:  # Python 3
    import socketserver
except ImportError:  # Python 2
    import SocketServer as socketserver
import ssl
import sys
import threading
import time
import traceback
try:  # Python 3
    import urllib.parse as urllib_parse
except ImportError:  # Python 2
    import urlparse as urllib_parse


LOG = logging.getLogger(__name__)
LOG.setLevel(logging.ERROR)
LOG_LEVELS = ['critical', 'error', 'warning', 'info', 'debug']

try:  # Python 2
    UNICODE_TYPE = unicode
except NameError:  # Python 3
    UNICODE_TYPE = str


# Sketch of implementation:
#
# One Irker object manages multiple IRC sessions.  It holds a map of
# Dispatcher objects, one per (server, port) combination, which are
# responsible for routing messages to one of any number of Connection
# objects that do the actual socket conversations.  The reason for the
# Dispatcher layer is that IRC daemons limit the number of channels a
# client (that is, from the daemon's point of view, a socket) can be
# joined to, so each session to a server needs a flock of Connection
# instances each with its own socket.
#
# Connections are timed out and removed when either they haven't seen a
# PING for a while (indicating that the server may be stalled or down)
# or there has been no message traffic to them for a while, or
# even if the queue is nonempty but efforts to connect have failed for
# a long time.
#
# There are multiple threads. One accepts incoming traffic from all
# servers.  Each Connection also has a consumer thread and a
# thread-safe message queue.  The program main appends messages to
# queues as JSON requests are received; the consumer threads try to
# ship them to servers.  When a socket write stalls, it only blocks an
# individual consumer thread; if it stalls long enough, the session
# will be timed out. This solves the biggest problem with a
# single-threaded implementation, which is that you can't count on a
# single stalled write not hanging all other traffic - you're at the
# mercy of the length of the buffers in the TCP/IP layer.
#
# Message delivery is thus not reliable in the face of network stalls,
# but this was considered acceptable because IRC (notoriously) has the
# same problem - there is little point in reliable delivery to a relay
# that is down or unreliable.
#
# This code uses only NICK, JOIN, PART, MODE, PRIVMSG, USER, and QUIT.
# It is strictly compliant to RFC1459, except for the interpretation and
# use of the DEAF and CHANLIMIT and (obsolete) MAXCHANNELS features.
#
# CHANLIMIT is as described in the Internet RFC draft
# draft-brocklesby-irc-isupport-03 at <http://www.mirc.com/isupport.html>.
# The ",isnick" feature is as described in
# <http://ftp.ics.uci.edu/pub/ietf/uri/draft-mirashi-url-irc-01.txt>.

# Historical note: the IRCClient and IRCServerConnection classes
# (~270LOC) replace the overweight, overcomplicated 3KLOC mass of
# irclib code that irker formerly used as a service library.  They
# still look similar to parts of irclib because I contributed to that
# code before giving up on it.

class IRCError(Exception):
    "An IRC exception"
    pass


class InvalidRequest(ValueError):
    "An invalid JSON request"
    pass


class IRCClient():
    "An IRC client session to one or more servers."
    def __init__(self):
        self.mutex = threading.RLock()
        self.server_connections = []
        self.event_handlers = {}
        self.add_event_handler("ping",
                               lambda c, e: c.ship("PONG %s" % e.target))

    def newserver(self):
        "Initialize a new server-connection object."
        conn = IRCServerConnection(self)
        with self.mutex:
            self.server_connections.append(conn)
        return conn

    def spin(self, timeout=0.2):
        "Spin processing data from connections forever."
        # Outer loop should specifically *not* be mutex-locked.
        # Otherwise no other thread would ever be able to change
        # the shared state of an IRC object running this function.
        while True:
            nextsleep = 0
            with self.mutex:
                connected = [x for x in self.server_connections
                             if x is not None and x.socket is not None]
                sockets = [x.socket for x in connected]
                if sockets:
                    connmap = dict([(c.socket.fileno(), c) for c in connected])
                    (insocks, _o, _e) = select.select(sockets, [], [], timeout)
                    for s in insocks:
                        try:
                            connmap[s.fileno()].consume()
                        except UnicodeDecodeError as e:
                            LOG.warn('{0}: invalid encoding ({1})'.format(
                                self, e))
                else:
                    nextsleep = timeout
            time.sleep(nextsleep)

    def add_event_handler(self, event, handler):
        "Set a handler to be called later."
        with self.mutex:
            event_handlers = self.event_handlers.setdefault(event, [])
            event_handlers.append(handler)

    def handle_event(self, connection, event):
        with self.mutex:
            h = self.event_handlers
            th = sorted(h.get("all_events", []) + h.get(event.type, []))
            for handler in th:
                handler(connection, event)

    def drop_connection(self, connection):
        with self.mutex:
            self.server_connections.remove(connection)


class LineBufferedStream():
    "Line-buffer a read stream."
    _crlf_re = re.compile(b'\r?\n')

    def __init__(self):
        self.buffer = b''

    def append(self, newbytes):
        self.buffer += newbytes

    def lines(self):
        "Iterate over lines in the buffer."
        lines = self._crlf_re.split(self.buffer)
        self.buffer = lines.pop()
        return iter(lines)

    def __iter__(self):
        return self.lines()

class IRCServerConnectionError(IRCError):
    pass

class IRCServerConnection():
    command_re = re.compile("^(:(?P<prefix>[^ ]+) +)?(?P<command>[^ ]+)( *(?P<argument> .+))?")
    # The full list of numeric-to-event mappings is in Perl's Net::IRC.
    # We only need to ensure that if some ancient server throws numerics
    # for the ones we actually want to catch, they're mapped.
    codemap = {
        "001": "welcome",
        "005": "featurelist",
        "432": "erroneusnickname",
        "433": "nicknameinuse",
        "436": "nickcollision",
        "437": "unavailresource",
    }

    def __init__(self, master):
        self.master = master
        self.socket = None

    def _wrap_socket(self, socket, target, certfile=None, cafile=None,
                     protocol=ssl.PROTOCOL_TLSv1):
        try:  # Python 3.2 and greater
            ssl_context = ssl.SSLContext(protocol)
        except AttributeError:  # Python < 3.2
            self.socket = ssl.wrap_socket(
                socket, certfile=certfile, cert_reqs=ssl.CERT_REQUIRED,
                ssl_version=protocol, ca_certs=cafile)
        else:
            ssl_context.verify_mode = ssl.CERT_REQUIRED
            if cafile:
                ssl_context.load_verify_locations(cafile=cafile)
            else:
                ssl_context.set_default_verify_paths()
            kwargs = {}
            if ssl.HAS_SNI:
                kwargs['server_hostname'] = target.servername
            self.socket = ssl_context.wrap_socket(socket, **kwargs)
        return self.socket

    def _check_hostname(self, target):
        if hasattr(ssl, 'match_hostname'):  # Python >= 3.2
            cert = self.socket.getpeercert()
            try:
                ssl.match_hostname(cert, target.servername)
            except ssl.CertificateError as e:
                raise IRCServerConnectionError(
                    'Invalid SSL/TLS certificate: %s' % e)
        else:  # Python < 3.2
            LOG.warning(
                'cannot check SSL/TLS hostname with Python %s' % sys.version)

    def connect(self, target, nickname, username=None, realname=None,
                **kwargs):
        LOG.debug("connect(server=%r, port=%r, nickname=%r, ...)" % (
            target.servername, target.port, nickname))
        if self.socket is not None:
            self.disconnect("Changing servers")

        self.buffer = LineBufferedStream()
        self.event_handlers = {}
        self.real_server_name = ""
        self.target = target
        self.nickname = nickname
        try:
            self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            if target.ssl:
                self.socket = self._wrap_socket(
                    socket=self.socket, target=target, **kwargs)
            self.socket.bind(('', 0))
            self.socket.connect((target.servername, target.port))
        except socket.error as err:
            raise IRCServerConnectionError("Couldn't connect to socket: %s" % err)

        if target.ssl:
            self._check_hostname(target=target)
        if target.password:
            self.ship("PASS " + target.password)
        self.nick(self.nickname)
        self.user(
            username=target.username or username or 'irker',
            realname=realname or 'irker relaying client')
        return self

    def close(self):
        # Without this thread lock, there is a window during which
        # select() can find a closed socket, leading to an EBADF error.
        with self.master.mutex:
            self.disconnect("Closing object")
            self.master.drop_connection(self)

    def consume(self):
        try:
            incoming = self.socket.recv(16384)
        except socket.error:
            # Server hung up on us.
            self.disconnect("Connection reset by peer")
            return
        if not incoming:
            # Dead air also indicates a connection reset.
            self.disconnect("Connection reset by peer")
            return

        self.buffer.append(incoming)

        for line in self.buffer:
            if not isinstance(line, UNICODE_TYPE):
                line = UNICODE_TYPE(line, 'utf-8')
                LOG.debug("FROM: %s" % line)

            if not line:
                continue

            prefix = None
            command = None
            arguments = None
            self.handle_event(Event("every_raw_message",
                                     self.real_server_name,
                                     None,
                                     [line]))

            m = IRCServerConnection.command_re.match(line)
            if m.group("prefix"):
                prefix = m.group("prefix")
                if not self.real_server_name:
                    self.real_server_name = prefix
            if m.group("command"):
                command = m.group("command").lower()
            if m.group("argument"):
                a = m.group("argument").split(" :", 1)
                arguments = a[0].split()
                if len(a) == 2:
                    arguments.append(a[1])

            command = IRCServerConnection.codemap.get(command, command)
            if command in ["privmsg", "notice"]:
                target = arguments.pop(0)
            else:
                target = None

                if command == "quit":
                    arguments = [arguments[0]]
                elif command == "ping":
                    target = arguments[0]
                else:
                    target = arguments[0]
                    arguments = arguments[1:]

            LOG.debug("command: %s, source: %s, target: %s, arguments: %s" % (
                command, prefix, target, arguments))
            self.handle_event(Event(command, prefix, target, arguments))

    def handle_event(self, event):
        self.master.handle_event(self, event)
        if event.type in self.event_handlers:
            for fn in self.event_handlers[event.type]:
                fn(self, event)

    def is_connected(self):
        return self.socket is not None

    def disconnect(self, message=""):
        if self.socket is None:
            return
        # Don't send a QUIT here - causes infinite loop!
        try:
            self.socket.shutdown(socket.SHUT_WR)
            self.socket.close()
        except socket.error:
            pass
        del self.socket
        self.socket = None
        self.handle_event(
            Event("disconnect", self.target.server, "", [message]))

    def join(self, channel, key=""):
        self.ship("JOIN %s%s" % (channel, (key and (" " + key))))

    def mode(self, target, command):
        self.ship("MODE %s %s" % (target, command))

    def nick(self, newnick):
        self.ship("NICK " + newnick)

    def part(self, channel, message=""):
        cmd_parts = ['PART', channel]
        if message:
            cmd_parts.append(message)
        self.ship(' '.join(cmd_parts))

    def privmsg(self, target, text):
        self.ship("PRIVMSG %s :%s" % (target, text))

    def quit(self, message=""):
        self.ship("QUIT" + (message and (" :" + message)))

    def user(self, username, realname):
        self.ship("USER %s 0 * :%s" % (username, realname))

    def ship(self, string):
        "Ship a command to the server, appending CR/LF"
        try:
            self.socket.send(string.encode('utf-8') + b'\r\n')
            LOG.debug("TO: %s" % string)
        except socket.error:
            self.disconnect("Connection reset by peer.")

class Event(object):
    def __init__(self, evtype, source, target, arguments=None):
        self.type = evtype
        self.source = source
        self.target = target
        if arguments is None:
            arguments = []
        self.arguments = arguments

def is_channel(string):
    return string and string[0] in "#&+!"

class Connection:
    def __init__(self, irker, target, nick_template, nick_needs_number=False,
                 password=None, **kwargs):
        self.irker = irker
        self.target = target
        self.nick_template = nick_template
        self.nick_needs_number = nick_needs_number
        self.password = password
        self.kwargs = kwargs
        self.nick_trial = None
        self.connection = None
        self.status = None
        self.last_xmit = time.time()
        self.last_ping = time.time()
        self.channels_joined = {}
        self.channel_limits = {}
        # The consumer thread
        self.queue = queue.Queue()
        self.thread = None
    def nickname(self, n=None):
        "Return a name for the nth server connection."
        if n is None:
            n = self.nick_trial
        if self.nick_needs_number:
            return self.nick_template % n
        else:
            return self.nick_template
    def handle_ping(self):
        "Register the fact that the server has pinged this connection."
        self.last_ping = time.time()
    def handle_welcome(self):
        "The server says we're OK, with a non-conflicting nick."
        self.status = "ready"
        LOG.info("nick %s accepted" % self.nickname())
        if self.password:
            self.connection.privmsg("nickserv", "identify %s" % self.password)
    def handle_badnick(self):
        "The server says our nick is ill-formed or has a conflict."
        LOG.info("nick %s rejected" % self.nickname())
        if self.nick_needs_number:
            # Randomness prevents a malicious user or bot from
            # anticipating the next trial name in order to block us
            # from completing the handshake.
            self.nick_trial += random.randint(1, 3)
            self.last_xmit = time.time()
            self.connection.nick(self.nickname())
        # Otherwise fall through, it might be possible to
        # recover manually.
    def handle_disconnect(self):
        "Server disconnected us for flooding or some other reason."
        self.connection = None
        if self.status != "expired":
            self.status = "disconnected"
    def handle_kick(self, outof):
        "We've been kicked."
        self.status = "handshaking"
        try:
            del self.channels_joined[outof]
        except KeyError:
            LOG.error("irkerd: kicked by %s from %s that's not joined" % (
                self.target, outof))
        qcopy = []
        while not self.queue.empty():
            (channel, message, key) = self.queue.get()
            if channel != outof:
                qcopy.append((channel, message, key))
        for (channel, message, key) in qcopy:
            self.queue.put((channel, message, key))
        self.status = "ready"
    def enqueue(self, channel, message, key, quit_after=False):
        "Enque a message for transmission."
        if self.thread is None or not self.thread.is_alive():
            self.status = "unseen"
            self.thread = threading.Thread(target=self.dequeue)
            self.thread.setDaemon(True)
            self.thread.start()
        self.queue.put((channel, message, key))
        if quit_after:
            self.queue.put((channel, None, key))
    def dequeue(self):
        "Try to ship pending messages from the queue."
        try:
            while True:
                # We want to be kind to the IRC servers and not hold unused
                # sockets open forever, so they have a time-to-live.  The
                # loop is coded this particular way so that we can drop
                # the actual server connection when its time-to-live
                # expires, then reconnect and resume transmission if the
                # queue fills up again.
                if self.queue.empty():
                    # Queue is empty, at some point we want to time out
                    # the connection rather than holding a socket open in
                    # the server forever.
                    now = time.time()
                    xmit_timeout = now > self.last_xmit + XMIT_TTL
                    ping_timeout = now > self.last_ping + PING_TTL
                    if self.status == "disconnected":
                        # If the queue is empty, we can drop this connection.
                        self.status = "expired"
                        break
                    elif xmit_timeout or ping_timeout:
                        LOG.info((
                            "timing out connection to %s at %s "
                            "(ping_timeout=%s, xmit_timeout=%s)") % (
                            self.target, time.asctime(), ping_timeout,
                            xmit_timeout))
                        with self.irker.irc.mutex:
                            self.connection.context = None
                            self.connection.quit("transmission timeout")
                            self.connection = None
                        self.status = "disconnected"
                    else:
                        # Prevent this thread from hogging the CPU by pausing
                        # for just a little bit after the queue-empty check.
                        # As long as this is less that the duration of a human
                        # reflex arc it is highly unlikely any human will ever
                        # notice.
                        time.sleep(ANTI_BUZZ_DELAY)
                elif self.status == "disconnected" \
                         and time.time() > self.last_xmit + DISCONNECT_TTL:
                    # Queue is nonempty, but the IRC server might be
                    # down. Letting failed connections retain queue
                    # space forever would be a memory leak.
                    self.status = "expired"
                    break
                elif not self.connection and self.status != "expired":
                    # Queue is nonempty but server isn't connected.
                    with self.irker.irc.mutex:
                        self.connection = self.irker.irc.newserver()
                        self.connection.context = self
                        # Try to avoid colliding with other instances
                        self.nick_trial = random.randint(1, 990)
                        self.channels_joined = {}
                        try:
                            # This will throw
                            # IRCServerConnectionError on failure
                            self.connection.connect(
                                target=self.target,
                                nickname=self.nickname(),
                                **self.kwargs)
                            self.status = "handshaking"
                            LOG.info("XMIT_TTL bump (%s connection) at %s" % (
                                self.target, time.asctime()))
                            self.last_xmit = time.time()
                            self.last_ping = time.time()
                        except IRCServerConnectionError as e:
                            LOG.error("irkerd: %s" % e)
                            self.status = "expired"
                            break
                elif self.status == "handshaking":
                    if time.time() > self.last_xmit + HANDSHAKE_TTL:
                        self.status = "expired"
                        break
                    else:
                        # Don't buzz on the empty-queue test while we're
                        # handshaking
                        time.sleep(ANTI_BUZZ_DELAY)
                elif self.status == "unseen" \
                         and time.time() > self.last_xmit + UNSEEN_TTL:
                    # Nasty people could attempt a denial-of-service
                    # attack by flooding us with requests with invalid
                    # servernames. We guard against this by rapidly
                    # expiring connections that have a nonempty queue but
                    # have never had a successful open.
                    self.status = "expired"
                    break
                elif self.status == "ready":
                    (channel, message, key) = self.queue.get()
                    if channel not in self.channels_joined:
                        self.connection.join(channel, key=key)
                        LOG.info("joining %s on %s." % (channel, self.target))
                    # None is magic - it's a request to quit the server
                    if message is None:
                        self.connection.quit()
                    # An empty message might be used as a keepalive or
                    # to join a channel for logging, so suppress the
                    # privmsg send unless there is actual traffic.
                    elif message:
                        for segment in message.split("\n"):
                            # Truncate the message if it's too long,
                            # but we're working with characters here,
                            # not bytes, so we could be off.
                            # 500 = 512 - CRLF - 'PRIVMSG ' - ' :'
                            maxlength = 500 - len(channel)
                            if len(segment) > maxlength:
                                segment = segment[:maxlength]
                            try:
                                self.connection.privmsg(channel, segment)
                            except ValueError as err:
                                LOG.warning((
                                    "irclib rejected a message to %s on %s "
                                    "because: %s") % (
                                    channel, self.target, UNICODE_TYPE(err)))
                                LOG.debug(traceback.format_exc())
                            time.sleep(ANTI_FLOOD_DELAY)
                    self.last_xmit = self.channels_joined[channel] = time.time()
                    LOG.info("XMIT_TTL bump (%s transmission) at %s" % (
                        self.target, time.asctime()))
                    self.queue.task_done()
                elif self.status == "expired":
                    LOG.error(
                        "irkerd: we're expired but still running! This is a bug.")
                    break
        except Exception as e:
            LOG.error("irkerd: exception %s in thread for %s" % (e, self.target))
            # Maybe this should have its own status?
            self.status = "expired"
            LOG.debug(traceback.format_exc())
        finally:
            try:
                # Make sure we don't leave any zombies behind
                self.connection.close()
            except:
                # Irclib has a habit of throwing fresh exceptions here. Ignore that
                pass
    def live(self):
        "Should this connection not be scavenged?"
        return self.status != "expired"
    def joined_to(self, channel):
        "Is this connection joined to the specified channel?"
        return channel in self.channels_joined
    def accepting(self, channel):
        "Can this connection accept a join of this channel?"
        if self.channel_limits:
            match_count = 0
            for already in self.channels_joined:
                # This obscure code is because the RFCs allow separate limits
                # by channel type (indicated by the first character of the name)
                # a feature that is almost never actually used.
                if already[0] == channel[0]:
                    match_count += 1
            return match_count < self.channel_limits.get(channel[0], CHANNEL_MAX)
        else:
            return len(self.channels_joined) < CHANNEL_MAX

class Target():
    "Represent a transmission target."
    def __init__(self, url):
        self.url = url
        parsed = urllib_parse.urlparse(url)
        self.ssl = parsed.scheme == 'ircs'
        if self.ssl:
            default_ircport = 6697
        else:
            default_ircport = 6667
        self.username = parsed.username
        self.password = parsed.password
        self.servername = parsed.hostname
        self.port = parsed.port or default_ircport
        # IRC channel names are case-insensitive.  If we don't smash
        # case here we may run into problems later. There was a bug
        # observed on irc.rizon.net where an irkerd user specified #Channel,
        # got kicked, and irkerd crashed because the server returned
        # "#channel" in the notification that our kick handler saw.
        self.channel = parsed.path.lstrip('/').lower()
        # This deals with a tweak in recent versions of urlparse.
        if parsed.fragment:
            self.channel += "#" + parsed.fragment
        isnick = self.channel.endswith(",isnick")
        if isnick:
            self.channel = self.channel[:-7]
        if self.channel and not isnick and self.channel[0] not in "#&+":
            self.channel = "#" + self.channel
        # support both channel?secret and channel?key=secret
        self.key = ""
        if parsed.query:
            self.key = re.sub("^key=", "", parsed.query)

    def __str__(self):
        "Represent this instance as a string"
        return self.servername or self.url or repr(self)

    def validate(self):
        "Raise InvalidRequest if the URL is missing a critical component"
        if not self.servername:
            raise InvalidRequest(
                'target URL missing a servername: %r' % self.url)
        if not self.channel:
            raise InvalidRequest(
                'target URL missing a channel: %r' % self.url)
    def server(self):
        "Return a hashable tuple representing the destination server."
        return (self.servername, self.port)

class Dispatcher:
    "Manage connections to a particular server-port combination."
    def __init__(self, irker, **kwargs):
        self.irker = irker
        self.kwargs = kwargs
        self.connections = []
    def dispatch(self, channel, message, key, quit_after=False):
        "Dispatch messages for our server-port combination."
        # First, check if there is room for another channel
        # on any of our existing connections.
        connections = [x for x in self.connections if x.live()]
        eligibles = [x for x in connections if x.joined_to(channel)] \
                    or [x for x in connections if x.accepting(channel)]
        if eligibles:
            eligibles[0].enqueue(channel, message, key, quit_after)
            return
        # All connections are full up. Look for one old enough to be
        # scavenged.
        ancients = []
        for connection in connections:
            for (chan, age) in connections.channels_joined.items():
                if age < time.time() - CHANNEL_TTL:
                    ancients.append((connection, chan, age))
        if ancients:
            ancients.sort(key=lambda x: x[2])
            (found_connection, drop_channel, _drop_age) = ancients[0]
            found_connection.part(drop_channel, "scavenged by irkerd")
            del found_connection.channels_joined[drop_channel]
            #time.sleep(ANTI_FLOOD_DELAY)
            found_connection.enqueue(channel, message, key, quit_after)
            return
        # All existing channels had recent activity
        newconn = Connection(self.irker, **self.kwargs)
        self.connections.append(newconn)
        newconn.enqueue(channel, message, key, quit_after)
    def live(self):
        "Does this server-port combination have any live connections?"
        self.connections = [x for x in self.connections if x.live()]
        return len(self.connections) > 0
    def pending(self):
        "Return all connections with pending traffic."
        return [x for x in self.connections if not x.queue.empty()]
    def last_xmit(self):
        "Return the time of the most recent transmission."
        return max(x.last_xmit for x in self.connections)

class Irker:
    "Persistent IRC multiplexer."
    def __init__(self, logfile=None, **kwargs):
        self.logfile = logfile
        self.kwargs = kwargs
        self.irc = IRCClient()
        self.irc.add_event_handler("ping", self._handle_ping)
        self.irc.add_event_handler("welcome", self._handle_welcome)
        self.irc.add_event_handler("erroneusnickname", self._handle_badnick)
        self.irc.add_event_handler("nicknameinuse", self._handle_badnick)
        self.irc.add_event_handler("nickcollision", self._handle_badnick)
        self.irc.add_event_handler("unavailresource", self._handle_badnick)
        self.irc.add_event_handler("featurelist", self._handle_features)
        self.irc.add_event_handler("disconnect", self._handle_disconnect)
        self.irc.add_event_handler("kick", self._handle_kick)
        self.irc.add_event_handler("every_raw_message", self._handle_every_raw_message)
        self.servers = {}
    def thread_launch(self):
        thread = threading.Thread(target=self.irc.spin)
        thread.setDaemon(True)
        self.irc._thread = thread
        thread.start()
    def _handle_ping(self, connection, _event):
        "PING arrived, bump the last-received time for the connection."
        if connection.context:
            connection.context.handle_ping()
    def _handle_welcome(self, connection, _event):
        "Welcome arrived, nick accepted for this connection."
        if connection.context:
            connection.context.handle_welcome()
    def _handle_badnick(self, connection, _event):
        "Nick not accepted for this connection."
        if connection.context:
            connection.context.handle_badnick()
    def _handle_features(self, connection, event):
        "Determine if and how we can set deaf mode."
        if connection.context:
            cxt = connection.context
            arguments = event.arguments
            for lump in arguments:
                if lump.startswith("DEAF="):
                    if not self.logfile:
                        connection.mode(cxt.nickname(), "+"+lump[5:])
                elif lump.startswith("MAXCHANNELS="):
                    m = int(lump[12:])
                    for pref in "#&+":
                        cxt.channel_limits[pref] = m
                    LOG.info("%s maxchannels is %d" % (connection.target, m))
                elif lump.startswith("CHANLIMIT=#:"):
                    limits = lump[10:].split(",")
                    try:
                        for token in limits:
                            (prefixes, limit) = token.split(":")
                            limit = int(limit)
                            for c in prefixes:
                                cxt.channel_limits[c] = limit
                        LOG.info("%s channel limit map is %s" % (
                            connection.target, cxt.channel_limits))
                    except ValueError:
                        LOG.error("irkerd: ill-formed CHANLIMIT property")
    def _handle_disconnect(self, connection, _event):
        "Server hung up the connection."
        LOG.info("server %s disconnected" % connection.target)
        connection.close()
        if connection.context:
            connection.context.handle_disconnect()
    def _handle_kick(self, connection, event):
        "Server hung up the connection."
        target = event.target
        LOG.info("irker has been kicked from %s on %s" % (
            target, connection.target))
        if connection.context:
            connection.context.handle_kick(target)
    def _handle_every_raw_message(self, _connection, event):
        "Log all messages when in watcher mode."
        if self.logfile:
            with open(self.logfile, "a") as logfp:
                logfp.write("%03f|%s|%s\n" % \
                             (time.time(), event.source, event.arguments[0]))
    def pending(self):
        "Do we have any pending message traffic?"
        return [k for (k, v) in self.servers.items() if v.pending()]

    def _parse_request(self, line):
        "Request-parsing helper for the handle() method"
        request = json.loads(line.strip())
        if not isinstance(request, dict):
            raise InvalidRequest(
                "request is not a JSON dictionary: %r" % request)
        if "to" not in request or "privmsg" not in request:
            raise InvalidRequest(
                "malformed request - 'to' or 'privmsg' missing: %r" % request)
        channels = request['to']
        message = request['privmsg']
        if not isinstance(channels, (list, UNICODE_TYPE)):
            raise InvalidRequest(
                "malformed request - unexpected channel type: %r" % channels)
        if not isinstance(message, UNICODE_TYPE):
            raise InvalidRequest(
                "malformed request - unexpected message type: %r" % message)
        if not isinstance(channels, list):
            channels = [channels]
        targets = []
        for url in channels:
            try:
                if not isinstance(url, UNICODE_TYPE):
                    raise InvalidRequest(
                        "malformed request - URL has unexpected type: %r" %
                        url)
                target = Target(url)
                target.validate()
            except InvalidRequest as e:
                LOG.error("irkerd: " + UNICODE_TYPE(e))
            else:
                targets.append(target)
        return (targets, message)

    def handle(self, line, quit_after=False):
        "Perform a JSON relay request."
        try:
            targets, message = self._parse_request(line=line)
            for target in targets:
                if target.server() not in self.servers:
                    self.servers[target.server()] = Dispatcher(
                        self, target=target, **self.kwargs)
                self.servers[target.server()].dispatch(
                    target.channel, message, target.key, quit_after=quit_after)
                # GC dispatchers with no active connections
                servernames = self.servers.keys()
                for servername in servernames:
                    if not self.servers[servername].live():
                        del self.servers[servername]
                    # If we might be pushing a resource limit even
                    # after garbage collection, remove a session.  The
                    # goal here is to head off DoS attacks that aim at
                    # exhausting thread space or file descriptors.
                    # The cost is that attempts to DoS this service
                    # will cause lots of join/leave spam as we
                    # scavenge old channels after connecting to new
                    # ones. The particular method used for selecting a
                    # session to be terminated doesn't matter much; we
                    # choose the one longest idle on the assumption
                    # that message activity is likely to be clumpy.
                    if len(self.servers) >= CONNECTION_MAX:
                        oldest = min(
                            self.servers.keys(),
                            key=lambda name: self.servers[name].last_xmit())
                        del self.servers[oldest]
        except InvalidRequest as e:
            LOG.error("irkerd: " + UNICODE_TYPE(e))
        except ValueError:
            LOG.error("irkerd: " + "can't recognize JSON on input: %r" % line)
        except RuntimeError:
            LOG.error("irkerd: " + "wildly malformed JSON blew the parser stack.")

class IrkerTCPHandler(socketserver.StreamRequestHandler):
    def handle(self):
        while True:
            line = self.rfile.readline()
            if not line:
                break
            if not isinstance(line, UNICODE_TYPE):
                line = UNICODE_TYPE(line, 'utf-8')
            irker.handle(line=line.strip())

class IrkerUDPHandler(socketserver.BaseRequestHandler):
    def handle(self):
        line = self.request[0].strip()
        #socket = self.request[1]
        if not isinstance(line, UNICODE_TYPE):
            line = UNICODE_TYPE(line, 'utf-8')
        irker.handle(line=line.strip())

def in_background():
    "Is this process running in background?"
    try:
        return os.getpgrp() != os.tcgetpgrp(1)
    except OSError:
        return True

if __name__ == '__main__':
    parser = argparse.ArgumentParser(
        description=__doc__.strip().splitlines()[0])
    parser.add_argument(
        '-c', '--ca-file', metavar='PATH',
        help='file of trusted certificates for SSL/TLS')
    parser.add_argument(
        '-e', '--cert-file', metavar='PATH',
        help='pem file used to authenticate to the server')
    parser.add_argument(
        '-d', '--log-level', metavar='LEVEL', choices=LOG_LEVELS,
        help='how much to log to the log file (one of %(choices)s)')
    parser.add_argument(
        '-H', '--host', metavar='ADDRESS', default=HOST,
        help='IP address to listen on')
    parser.add_argument(
        '-l', '--log-file', metavar='PATH',
        help='file for saving captured message traffic')
    parser.add_argument(
        '-n', '--nick', metavar='NAME', default='irker%03d',
        help="nickname (optionally with a '%%.*d' server connection marker)")
    parser.add_argument(
        '-p', '--password', metavar='PASSWORD',
        help='NickServ password')
    parser.add_argument(
        '-i', '--immediate', metavar='IRC-URL',
        help=(
            'send a single message to IRC-URL and exit.  The message is the '
            'first positional argument.'))
    parser.add_argument(
        '-V', '--version', action='version',
        version='%(prog)s {0}'.format(version))
    parser.add_argument(
        'message', metavar='MESSAGE', nargs='?',
        help='message for --immediate mode')
    args = parser.parse_args()

    if not args.log_file and in_background():
        # The Linux, Mac, and FreeBSD values of the logging device.
        logdev = [x for x in ('/dev/log', '/var/run/syslog', '/var/run/log')
                  if os.path.exists(x)]
        if len(logdev) != 1:
            sys.stderr.write("can't initialize log device, bailing out!\n")
            raise SystemExit(1)
        # There's a case for falling back to address = ('localhost', 514)
        # But some systems (including OS X) disable this for security reasons.
        handler = logging.handlers.SysLogHandler(address=logdev[0],
                                                 facility='daemon')
    else:
        handler = logging.StreamHandler()

    LOG.addHandler(handler)
    if args.log_level:
        log_level = getattr(logging, args.log_level.upper())
        LOG.setLevel(log_level)

    irker = Irker(
        logfile=args.log_file,
        nick_template=args.nick,
        nick_needs_number=re.search('%.*d', args.nick),
        password=args.password,
        cafile=args.ca_file,
        certfile=args.cert_file,
        )
    LOG.info("irkerd version %s" % version)
    if args.immediate:
        if not args.message:
            # We want newline to become '\n' and tab to become '\t';
            # the JSON decoder will undo these transformations.
            # This will also encode backslash, backspace, formfeed,
            # and high-half characters, which might produce unexpected
            # results on output.
            args.message = sys.stdin.read().encode("string_escape")
        irker.irc.add_event_handler("quit", lambda _c, _e: sys.exit(0))
        irker.handle('{"to":"%s","privmsg":"%s"}' % (
            args.immediate, args.message), quit_after=True)
        irker.irc.spin()
    else:
        if args.message:
            LOG.error(
                'irkerd: message argument given (%r), but --immediate not set' % (
                args.message))
            raise SystemExit(1)
        irker.thread_launch()
        try:
            tcpserver = socketserver.TCPServer((args.host, PORT), IrkerTCPHandler)
            udpserver = socketserver.UDPServer((args.host, PORT), IrkerUDPHandler)
            for server in [tcpserver, udpserver]:
                server = threading.Thread(target=server.serve_forever)
                server.setDaemon(True)
                server.start()
            try:
                signal.pause()
            except KeyboardInterrupt:
                raise SystemExit(1)
        except socket.error as e:
            LOG.error("irkerd: server launch failed: %r\n" % e)

# end