mdw@git.distorted.org.uk Git - hippotat/blob - hippotatlib/__init__.py

   1 # -*- python -*-
   2 #
   3 # Hippotat - Asinine IP Over HTTP program
   4 # hippotatlib/__init__.py - common library code
   5 #
   6 # Copyright 2017 Ian Jackson
   7 #
   8 # GPLv3+
   9 #
  10 #    This program is free software: you can redistribute it and/or modify
  11 #    it under the terms of the GNU General Public License as published by
  12 #    the Free Software Foundation, either version 3 of the License, or
  13 #    (at your option) any later version.
  14 #
  15 #    This program is distributed in the hope that it will be useful,
  16 #    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 #    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 #    GNU General Public License for more details.
  19 #
  20 #    You should have received a copy of the GNU General Public License
  21 #    along with this program, in the file GPLv3.  If not,
  22 #    see <http://www.gnu.org/licenses/>.
  23
  24
  25 import signal
  26 signal.signal(signal.SIGINT, signal.SIG_DFL)
  27
  28 import sys
  29 import os
  30
  31 from zope.interface import implementer
  32
  33 import twisted
  34 from twisted.internet import reactor
  35 import twisted.internet.endpoints
  36 import twisted.logger
  37 from twisted.logger import LogLevel
  38 import twisted.python.constants
  39 from twisted.python.constants import NamedConstant
  40
  41 import ipaddress
  42 from ipaddress import AddressValueError
  43
  44 from optparse import OptionParser
  45 import configparser
  46 from configparser import ConfigParser
  47 from configparser import NoOptionError
  48
  49 from functools import partial
  50
  51 import collections
  52 import time
  53 import hmac
  54 import hashlib
  55 import base64
  56 import codecs
  57 import traceback
  58
  59 import re as regexp
  60
  61 import hippotatlib.slip as slip
  62
  63 class DBG(twisted.python.constants.Names):
  64   INIT = NamedConstant()
  65   CONFIG = NamedConstant()
  66   ROUTE = NamedConstant()
  67   DROP = NamedConstant()
  68   OWNSOURCE = NamedConstant()
  69   FLOW = NamedConstant()
  70   HTTP = NamedConstant()
  71   TWISTED = NamedConstant()
  72   QUEUE = NamedConstant()
  73   HTTP_CTRL = NamedConstant()
  74   QUEUE_CTRL = NamedConstant()
  75   HTTP_FULL = NamedConstant()
  76   CTRL_DUMP = NamedConstant()
  77   SLIP_FULL = NamedConstant()
  78   DATA_COMPLETE = NamedConstant()
  79
  80 _hex_codec = codecs.getencoder('hex_codec')
  81
  82 #---------- logging ----------
  83
  84 org_stderr = sys.stderr
  85
  86 log = twisted.logger.Logger()
  87
  88 debug_set = set()
  89 debug_def_detail = DBG.HTTP
  90
  91 def log_debug(dflag, msg, idof=None, d=None):
  92   if dflag not in debug_set: return
  93   #print('---------------->',repr((dflag, msg, idof, d)), file=sys.stderr)
  94   if idof is not None:
  95     msg = '[%#x] %s' % (id(idof), msg)
  96   if d is not None:
  97     trunc = ''
  98     if not DBG.DATA_COMPLETE in debug_set:
  99       if len(d) > 64:
 100         d = d[0:64]
 101         trunc = '...'
 102     d = _hex_codec(d)[0].decode('ascii')
 103     msg += ' ' + d + trunc
 104   log.info('{dflag} {msgcore}', dflag=dflag, msgcore=msg)
 105
 106 def logevent_is_boringtwisted(event):
 107   try:
 108     if event.get('log_level') != LogLevel.info:
 109       return False
 110     dflag = event.get('dflag')
 111     if dflag is False                            : return False
 112     if dflag                         in debug_set: return False
 113     if dflag is None and DBG.TWISTED in debug_set: return False
 114     return True
 115   except Exception:
 116     print('EXCEPTION (IN BORINGTWISTED CHECK)',
 117           traceback.format_exc(), file=org_stderr)
 118     return False
 119
 120 @implementer(twisted.logger.ILogFilterPredicate)
 121 class LogNotBoringTwisted:
 122   def __call__(self, event):
 123     return (
 124       twisted.logger.PredicateResult.no
 125       if logevent_is_boringtwisted(event) else
 126       twisted.logger.PredicateResult.yes
 127     )
 128
 129 #---------- default config ----------
 130
 131 defcfg = '''
 132 [COMMON]
 133 max_batch_down = 65536
 134 max_queue_time = 10
 135 target_requests_outstanding = 3
 136 http_timeout = 30
 137 http_timeout_grace = 5
 138 max_requests_outstanding = 6
 139 max_batch_up = 4000
 140 http_retry = 5
 141 port = 80
 142 vroutes = ''
 143 ifname_client = hippo%%d
 144 ifname_server = shippo%%d
 145 max_clock_skew = 300
 146
 147 #[server] or [<client>] overrides
 148 ipif = userv root ipif %(local)s,%(peer)s,%(mtu)s,slip,%(ifname)s %(rnets)s
 149
 150 # relating to virtual network
 151 mtu = 1500
 152
 153 # addrs = 127.0.0.1 ::1
 154 # url
 155
 156 # relating to virtual network
 157 vvnetwork = 172.24.230.192
 158 # vnetwork = <prefix>/<len>
 159 # vaddr    = <ipaddr>
 160 # vrelay   = <ipaddr>
 161
 162
 163 # [<client-ip4-or-ipv6-address>]
 164 # secret = <secret>    # used by both, must match
 165
 166 [LIMIT]
 167 max_batch_down = 262144
 168 max_queue_time = 121
 169 http_timeout = 121
 170 target_requests_outstanding = 10
 171 '''
 172
 173 # these need to be defined here so that they can be imported by import *
 174 cfg = ConfigParser(strict=False)
 175 optparser = OptionParser()
 176
 177 _mimetrans = bytes.maketrans(b'-'+slip.esc, slip.esc+b'-')
 178 def mime_translate(s):
 179   # SLIP-encoded packets cannot contain ESC ESC.
 180   # Swap `-' and ESC.  The result cannot contain `--'
 181   return s.translate(_mimetrans)
 182
 183 class ConfigResults:
 184   def __init__(self):
 185     pass
 186   def __repr__(self):
 187     return 'ConfigResults('+repr(self.__dict__)+')'
 188
 189 def log_discard(packet, iface, saddr, daddr, why):
 190   log_debug(DBG.DROP,
 191             'discarded packet [%s] %s -> %s: %s' % (iface, saddr, daddr, why),
 192             d=packet)
 193
 194 #---------- packet parsing ----------
 195
 196 def packet_addrs(packet):
 197   version = packet[0] >> 4
 198   if version == 4:
 199     addrlen = 4
 200     saddroff = 3*4
 201     factory = ipaddress.IPv4Address
 202   elif version == 6:
 203     addrlen = 16
 204     saddroff = 2*4
 205     factory = ipaddress.IPv6Address
 206   else:
 207     raise ValueError('unsupported IP version %d' % version)
 208   saddr = factory(packet[ saddroff           : saddroff + addrlen   ])
 209   daddr = factory(packet[ saddroff + addrlen : saddroff + addrlen*2 ])
 210   return (saddr, daddr)
 211
 212 #---------- address handling ----------
 213
 214 def ipaddr(input):
 215   try:
 216     r = ipaddress.IPv4Address(input)
 217   except AddressValueError:
 218     r = ipaddress.IPv6Address(input)
 219   return r
 220
 221 def ipnetwork(input):
 222   try:
 223     r = ipaddress.IPv4Network(input)
 224   except NetworkValueError:
 225     r = ipaddress.IPv6Network(input)
 226   return r
 227
 228 #---------- ipif (SLIP) subprocess ----------
 229
 230 class SlipStreamDecoder():
 231   def __init__(self, desc, on_packet):
 232     self._buffer = b''
 233     self._on_packet = on_packet
 234     self._desc = desc
 235     self._log('__init__')
 236
 237   def _log(self, msg, **kwargs):
 238     log_debug(DBG.SLIP_FULL, 'slip %s: %s' % (self._desc, msg), **kwargs)
 239
 240   def inputdata(self, data):
 241     self._log('inputdata', d=data)
 242     data = self._buffer + data
 243     self._buffer = b''
 244     packets = slip.decode(data, True)
 245     self._buffer = packets.pop()
 246     for packet in packets:
 247       self._maybe_packet(packet)
 248     self._log('bufremain', d=self._buffer)
 249
 250   def _maybe_packet(self, packet):
 251     self._log('maybepacket', d=packet)
 252     if len(packet):
 253       self._on_packet(packet)
 254
 255   def flush(self):
 256     self._log('flush')
 257     data = self._buffer
 258     self._buffer = b''
 259     packets = slip.decode(data)
 260     assert(len(packets) == 1)
 261     self._maybe_packet(packets[0])
 262
 263 class _IpifProcessProtocol(twisted.internet.protocol.ProcessProtocol):
 264   def __init__(self, router):
 265     self._router = router
 266     self._decoder = SlipStreamDecoder('ipif', self.slip_on_packet)
 267   def connectionMade(self): pass
 268   def outReceived(self, data):
 269     self._decoder.inputdata(data)
 270   def slip_on_packet(self, packet):
 271     (saddr, daddr) = packet_addrs(packet)
 272     if saddr.is_link_local or daddr.is_link_local:
 273       log_discard(packet, 'ipif', saddr, daddr, 'link-local')
 274       return
 275     self._router(packet, saddr, daddr)
 276   def processEnded(self, status):
 277     status.raiseException()
 278
 279 def start_ipif(command, router):
 280   ipif = _IpifProcessProtocol(router)
 281   reactor.spawnProcess(ipif,
 282                        '/bin/sh',['sh','-xc', command],
 283                        childFDs={0:'w', 1:'r', 2:2},
 284                        env=None)
 285   return ipif
 286
 287 def queue_inbound(ipif, packet):
 288   log_debug(DBG.FLOW, "queue_inbound", d=packet)
 289   ipif.transport.write(slip.delimiter)
 290   ipif.transport.write(slip.encode(packet))
 291   ipif.transport.write(slip.delimiter)
 292
 293 #---------- packet queue ----------
 294
 295 class PacketQueue():
 296   def __init__(self, desc, max_queue_time):
 297     self._desc = desc
 298     assert(desc + '')
 299     self._max_queue_time = max_queue_time
 300     self._pq = collections.deque() # packets
 301
 302   def _log(self, dflag, msg, **kwargs):
 303     log_debug(dflag, self._desc+' pq: '+msg, **kwargs)
 304
 305   def append(self, packet):
 306     self._log(DBG.QUEUE, 'append', d=packet)
 307     self._pq.append((time.monotonic(), packet))
 308
 309   def nonempty(self):
 310     self._log(DBG.QUEUE, 'nonempty ?')
 311     while True:
 312       try: (queuetime, packet) = self._pq[0]
 313       except IndexError:
 314         self._log(DBG.QUEUE, 'nonempty ? empty.')
 315         return False
 316
 317       age = time.monotonic() - queuetime
 318       if age > self._max_queue_time:
 319         # strip old packets off the front
 320         self._log(DBG.QUEUE, 'dropping (old)', d=packet)
 321         self._pq.popleft()
 322         continue
 323
 324       self._log(DBG.QUEUE, 'nonempty ? nonempty.')
 325       return True
 326
 327   def process(self, sizequery, moredata, max_batch):
 328     # sizequery() should return size of batch so far
 329     # moredata(s) should add s to batch
 330     self._log(DBG.QUEUE, 'process...')
 331     while True:
 332       try: (dummy, packet) = self._pq[0]
 333       except IndexError:
 334         self._log(DBG.QUEUE, 'process... empty')
 335         break
 336
 337       self._log(DBG.QUEUE_CTRL, 'process... packet', d=packet)
 338
 339       encoded = slip.encode(packet)
 340       sofar = sizequery()
 341
 342       self._log(DBG.QUEUE_CTRL,
 343                 'process... (sofar=%d, max=%d) encoded' % (sofar, max_batch),
 344                 d=encoded)
 345
 346       if sofar > 0:
 347         if sofar + len(slip.delimiter) + len(encoded) > max_batch:
 348           self._log(DBG.QUEUE_CTRL, 'process... overflow')
 349           break
 350         moredata(slip.delimiter)
 351
 352       moredata(encoded)
 353       self._pq.popleft()
 354
 355 #---------- error handling ----------
 356
 357 _crashing = False
 358
 359 def crash(err):
 360   global _crashing
 361   _crashing = True
 362   print('========== CRASH ==========', err,
 363         '===========================', file=sys.stderr)
 364   try: reactor.stop()
 365   except twisted.internet.error.ReactorNotRunning: pass
 366
 367 def crash_on_defer(defer):
 368   defer.addErrback(lambda err: crash(err))
 369
 370 def crash_on_critical(event):
 371   if event.get('log_level') >= LogLevel.critical:
 372     crash(twisted.logger.formatEvent(event))
 373
 374 #---------- authentication tokens ----------
 375
 376 _authtoken_digest = hashlib.sha256
 377
 378 def _authtoken_time():
 379   return int(time.time())
 380
 381 def _authtoken_hmac(secret, hextime):
 382   return hmac.new(secret, hextime, _authtoken_digest).digest()
 383
 384 def authtoken_make(secret):
 385   hextime = ('%x' % _authtoken_time()).encode('ascii')
 386   mac = _authtoken_hmac(secret, hextime)
 387   return hextime + b' ' + base64.b64encode(mac)
 388
 389 def authtoken_check(secret, token, maxskew):
 390   (hextime, theirmac64) = token.split(b' ')
 391   now = _authtoken_time()
 392   then = int(hextime, 16)
 393   skew = then - now;
 394   if (abs(skew) > maxskew):
 395     raise ValueError('too much clock skew (client %ds ahead)' % skew)
 396   theirmac = base64.b64decode(theirmac64)
 397   ourmac = _authtoken_hmac(secret, hextime)
 398   if not hmac.compare_digest(theirmac, ourmac):
 399     raise ValueError('invalid token (wrong secret?)')
 400   pass
 401
 402 #---------- config processing ----------
 403
 404 def _cfg_process_putatives():
 405   servers = { }
 406   clients = { }
 407   # maps from abstract object to canonical name for cs's
 408
 409   def putative(cmap, abstract, canoncs):
 410     try:
 411       current_canoncs = cmap[abstract]
 412     except KeyError:
 413       pass
 414     else:
 415       assert(current_canoncs == canoncs)
 416     cmap[abstract] = canoncs
 417
 418   server_pat = r'[-.0-9A-Za-z]+'
 419   client_pat = r'[.:0-9a-f]+'
 420   server_re = regexp.compile(server_pat)
 421   serverclient_re = regexp.compile(
 422         server_pat + r' ' + '(?:' + client_pat + '|LIMIT)')
 423
 424   for cs in cfg.sections():
 425     def dbg(m):
 426       log_debug_config('putatives: section [%s] %s' % (cs, m))
 427
 428     def log_ignore(why):
 429       dbg('X ignore: %s' % (why))
 430       print('warning: ignoring config section [%s] (%s)' % (cs, why),
 431             file=sys.stderr)
 432
 433     if cs == 'LIMIT' or cs == 'COMMON':
 434       # plan A "[LIMIT]" or "[COMMON]"
 435       dbg('A ignore')
 436       continue
 437
 438     try:
 439       # plan B "[<client>]" part 1
 440       ci = ipaddr(cs)
 441     except AddressValueError:
 442
 443       if server_re.fullmatch(cs):
 444         # plan C "[<servername>]"
 445         dbg('C <server>')
 446         putative(servers, cs, cs)
 447         continue
 448
 449       if serverclient_re.fullmatch(cs):
 450         # plan D "[<servername> <client>]" part 1
 451         (pss,pcs) = cs.split(' ')
 452
 453         if pcs == 'LIMIT':
 454           # plan E "[<servername> LIMIT]"
 455           dbg('E <server> LIMIT')
 456           continue
 457
 458         try:
 459           # plan D "[<servername> <client>]" part 2
 460           ci = ipaddr(pcs)
 461         except AddressValueError:
 462           # plan F branch 1 "[<some thing we do not understand>]"
 463           log_ignore('bad-addr')
 464           continue
 465
 466         else: # no AddressValueError
 467           # plan D "[<servername> <client>]" part 3
 468           dbg('D <server> <client>')
 469           putative(clients, ci, pcs)
 470           putative(servers, pss, pss)
 471           continue
 472       else:
 473         # plan F branch 2 "[<some thing we do not understand>]"
 474         log_ignore('nomatch '+ repr(serverclient_re))
 475
 476     else: # no AddressValueError
 477       # plan B "[<client>" part 2
 478       dbg('B <client>')
 479       putative(clients, ci, cs)
 480       continue
 481
 482   return (servers, clients)
 483
 484 def cfg_process_general(c, ss):
 485   c.mtu = cfg1getint(ss, 'mtu')
 486
 487 def cfg_process_saddrs(c, ss):
 488   class ServerAddr():
 489     def __init__(self, port, addrspec):
 490       self.port = port
 491       # also self.addr
 492       try:
 493         self.addr = ipaddress.IPv4Address(addrspec)
 494         self._endpointfactory = twisted.internet.endpoints.TCP4ServerEndpoint
 495         self._inurl = b'%s'
 496       except AddressValueError:
 497         self.addr = ipaddress.IPv6Address(addrspec)
 498         self._endpointfactory = twisted.internet.endpoints.TCP6ServerEndpoint
 499         self._inurl = b'[%s]'
 500     def make_endpoint(self):
 501       return self._endpointfactory(reactor, self.port,
 502                                    interface= '%s' % self.addr)
 503     def url(self):
 504       url = b'http://' + (self._inurl % str(self.addr).encode('ascii'))
 505       if self.port != 80: url += b':%d' % self.port
 506       url += b'/'
 507       return url
 508     def __repr__(self):
 509       return 'ServerAddr'+repr((self.port,self.addr))
 510
 511   c.port = cfg1getint(ss,'port')
 512   c.saddrs = [ ]
 513   for addrspec in cfg1get(ss, 'addrs').split():
 514     sa = ServerAddr(c.port, addrspec)
 515     c.saddrs.append(sa)
 516
 517 def cfg_process_vnetwork(c, ss):
 518   c.vnetwork = ipnetwork(cfg1get(ss,'vnetwork'))
 519   if c.vnetwork.num_addresses < 3 + 2:
 520     raise ValueError('vnetwork needs at least 2^3 addresses')
 521
 522 def cfg_process_vaddr(c, ss):
 523   try:
 524     c.vaddr = cfg1get(ss,'vaddr')
 525   except NoOptionError:
 526     cfg_process_vnetwork(c, ss)
 527     c.vaddr = next(c.vnetwork.hosts())
 528
 529 def cfg_search_section(key,sections):
 530   for section in sections:
 531     if cfg.has_option(section, key):
 532       return section
 533   raise NoOptionError(key, repr(sections))
 534
 535 def cfg_get_raw(*args, **kwargs):
 536   # for passing to cfg_search
 537   return cfg.get(*args, raw=True, **kwargs)
 538
 539 def cfg_search(getter,key,sections):
 540   section = cfg_search_section(key,sections)
 541   return getter(section, key)
 542
 543 def cfg1get(section,key, getter=cfg.get,**kwargs):
 544   section = cfg_search_section(key,[section,'COMMON'])
 545   return getter(section,key,**kwargs)
 546
 547 def cfg1getint(section,key, **kwargs):
 548   return cfg1get(section,key, getter=cfg.getint,**kwargs);
 549
 550 def cfg_process_client_limited(cc,ss,sections,key):
 551   val = cfg_search(cfg1getint, key, sections)
 552   lim = cfg_search(cfg1getint, key, ['%s LIMIT' % ss, 'LIMIT'])
 553   cc.__dict__[key] = min(val,lim)
 554
 555 def cfg_process_client_common(cc,ss,cs,ci):
 556   # returns sections to search in, iff secret is defined, otherwise None
 557   cc.ci = ci
 558
 559   sections = ['%s %s' % (ss,cs),
 560               cs,
 561               ss,
 562               'COMMON']
 563
 564   try: pwsection = cfg_search_section('secret', sections)
 565   except NoOptionError: return None
 566
 567   pw = cfg1get(pwsection, 'secret')
 568   cc.secret = pw.encode('utf-8')
 569
 570   cfg_process_client_limited(cc,ss,sections,'target_requests_outstanding')
 571   cfg_process_client_limited(cc,ss,sections,'http_timeout')
 572
 573   return sections
 574
 575 def cfg_process_ipif(c, sections, varmap):
 576   for d, s in varmap:
 577     try: v = getattr(c, s)
 578     except AttributeError: continue
 579     setattr(c, d, v)
 580   for d in ('mtu',):
 581     v = cfg_search(cfg.get, d, sections)
 582     setattr(c, d, v)
 583
 584   #print('CFGIPIF',repr((varmap, sections, c.__dict__)),file=sys.stderr)
 585
 586   section = cfg_search_section('ipif', sections)
 587   c.ipif_command = cfg1get(section,'ipif', vars=c.__dict__)
 588
 589 #---------- startup ----------
 590
 591 def log_debug_config(m):
 592   if not DBG.CONFIG in debug_set: return
 593   print('DBG.CONFIG:', m)
 594
 595 def common_startup(process_cfg):
 596   # calls process_cfg(putative_clients, putative_servers)
 597
 598   # ConfigParser hates #-comments after values
 599   trailingcomments_re = regexp.compile(r'#.*')
 600   cfg.read_string(trailingcomments_re.sub('', defcfg))
 601   need_defcfg = True
 602
 603   def readconfig(pathname, mandatory=True):
 604     def log(m, p=pathname):
 605       if not DBG.CONFIG in debug_set: return
 606       log_debug_config('%s: %s' % (m, p))
 607
 608     try:
 609       files = os.listdir(pathname)
 610
 611     except FileNotFoundError:
 612       if mandatory: raise
 613       log('skipped')
 614       return
 615
 616     except NotADirectoryError:
 617       cfg.read(pathname)
 618       log('read file')
 619       return
 620
 621     # is a directory
 622     log('directory')
 623     re = regexp.compile('[^-A-Za-z0-9_]')
 624     for f in os.listdir(pathname):
 625       if re.search(f): continue
 626       subpath = pathname + '/' + f
 627       try:
 628         os.stat(subpath)
 629       except FileNotFoundError:
 630         log('entry skipped', subpath)
 631         continue
 632       cfg.read(subpath)
 633       log('entry read', subpath)
 634
 635   def oc_config(od,os, value, op):
 636     nonlocal need_defcfg
 637     need_defcfg = False
 638     readconfig(value)
 639
 640   def oc_extra_config(od,os, value, op):
 641     readconfig(value)
 642
 643   def read_defconfig():
 644     readconfig('/etc/hippotat/config.d', False)
 645     readconfig('/etc/hippotat/secrets.d', False)
 646     readconfig('/etc/hippotat/master.cfg',   False)
 647
 648   def oc_defconfig(od,os, value, op):
 649     nonlocal need_defcfg
 650     need_defcfg = False
 651     read_defconfig(value)
 652
 653   def dfs_less_detailed(dl):
 654     return [df for df in DBG.iterconstants() if df <= dl]
 655
 656   def ds_default(od,os,dl,op):
 657     global debug_set
 658     debug_set.clear
 659     debug_set |= set(dfs_less_detailed(debug_def_detail))
 660
 661   def ds_select(od,os, spec, op):
 662     for it in spec.split(','):
 663
 664       if it.startswith('-'):
 665         mutator = debug_set.discard
 666         it = it[1:]
 667       else:
 668         mutator = debug_set.add
 669
 670       if it == '+':
 671         dfs = DBG.iterconstants()
 672
 673       else:
 674         if it.endswith('+'):
 675           mapper = dfs_less_detailed
 676           it = it[0:len(it)-1]
 677         else:
 678           mapper = lambda x: [x]
 679
 680           try:
 681             dfspec = DBG.lookupByName(it)
 682           except ValueError:
 683             optparser.error('unknown debug flag %s in --debug-select' % it)
 684
 685         dfs = mapper(dfspec)
 686
 687       for df in dfs:
 688         mutator(df)
 689
 690   optparser.add_option('-D', '--debug',
 691                        nargs=0,
 692                        action='callback',
 693                        help='enable default debug (to stdout)',
 694                        callback= ds_default)
 695
 696   optparser.add_option('--debug-select',
 697                        nargs=1,
 698                        type='string',
 699                        metavar='[-]DFLAG[+]|[-]+,...',
 700                        help=
 701 '''enable (`-': disable) each specified DFLAG;
 702 `+': do same for all "more interesting" DFLAGSs;
 703 just `+': all DFLAGs.
 704   DFLAGS: ''' + ' '.join([df.name for df in DBG.iterconstants()]),
 705                        action='callback',
 706                        callback= ds_select)
 707
 708   optparser.add_option('-c', '--config',
 709                        nargs=1,
 710                        type='string',
 711                        metavar='CONFIGFILE',
 712                        dest='configfile',
 713                        action='callback',
 714                        callback= oc_config)
 715
 716   optparser.add_option('--extra-config',
 717                        nargs=1,
 718                        type='string',
 719                        metavar='CONFIGFILE',
 720                        dest='configfile',
 721                        action='callback',
 722                        callback= oc_extra_config)
 723
 724   optparser.add_option('--default-config',
 725                        action='callback',
 726                        callback= oc_defconfig)
 727
 728   (opts, args) = optparser.parse_args()
 729   if len(args): optparser.error('no non-option arguments please')
 730
 731   if need_defcfg:
 732     read_defconfig()
 733
 734   try:
 735     (pss, pcs) = _cfg_process_putatives()
 736     process_cfg(opts, pss, pcs)
 737   except (configparser.Error, ValueError):
 738     traceback.print_exc(file=sys.stderr)
 739     print('\nInvalid configuration, giving up.', file=sys.stderr)
 740     sys.exit(12)
 741
 742
 743   #print('X', debug_set, file=sys.stderr)
 744
 745   log_formatter = twisted.logger.formatEventAsClassicLogText
 746   stdout_obs = twisted.logger.FileLogObserver(sys.stdout, log_formatter)
 747   stderr_obs = twisted.logger.FileLogObserver(sys.stderr, log_formatter)
 748   pred = twisted.logger.LogLevelFilterPredicate(LogLevel.error)
 749   stdsomething_obs = twisted.logger.FilteringLogObserver(
 750     stderr_obs, [pred], stdout_obs
 751   )
 752   global file_log_observer
 753   file_log_observer = twisted.logger.FilteringLogObserver(
 754     stdsomething_obs, [LogNotBoringTwisted()]
 755   )
 756   #log_observer = stdsomething_obs
 757   twisted.logger.globalLogBeginner.beginLoggingTo(
 758     [ file_log_observer, crash_on_critical ]
 759     )
 760
 761 def common_run():
 762   log_debug(DBG.INIT, 'entering reactor')
 763   if not _crashing: reactor.run()
 764   print('ENDED', file=sys.stderr)
 765   sys.exit(16)