src/allmydata/mutable/servermap.py

   1
   2 import sys, time
   3 from zope.interface import implements
   4 from itertools import count
   5 from twisted.internet import defer
   6 from twisted.python import failure
   7 from foolscap.api import DeadReferenceError, RemoteException, eventually
   8 from allmydata.util import base32, hashutil, idlib, log
   9 from allmydata.storage.server import si_b2a
  10 from allmydata.interfaces import IServermapUpdaterStatus
  11 from pycryptopp.publickey import rsa
  12
  13 from common import MODE_CHECK, MODE_ANYTHING, MODE_WRITE, MODE_READ, \
  14      DictOfSets, CorruptShareError, NeedMoreDataError
  15 from layout import unpack_prefix_and_signature, unpack_header, unpack_share, \
  16      SIGNED_PREFIX_LENGTH
  17
  18 class UpdateStatus:
  19     implements(IServermapUpdaterStatus)
  20     statusid_counter = count(0)
  21     def __init__(self):
  22         self.timings = {}
  23         self.timings["per_server"] = {}
  24         self.timings["cumulative_verify"] = 0.0
  25         self.privkey_from = None
  26         self.problems = {}
  27         self.active = True
  28         self.storage_index = None
  29         self.mode = "?"
  30         self.status = "Not started"
  31         self.progress = 0.0
  32         self.counter = self.statusid_counter.next()
  33         self.started = time.time()
  34         self.finished = None
  35
  36     def add_per_server_time(self, peerid, op, sent, elapsed):
  37         assert op in ("query", "late", "privkey")
  38         if peerid not in self.timings["per_server"]:
  39             self.timings["per_server"][peerid] = []
  40         self.timings["per_server"][peerid].append((op,sent,elapsed))
  41
  42     def get_started(self):
  43         return self.started
  44     def get_finished(self):
  45         return self.finished
  46     def get_storage_index(self):
  47         return self.storage_index
  48     def get_mode(self):
  49         return self.mode
  50     def get_servermap(self):
  51         return self.servermap
  52     def get_privkey_from(self):
  53         return self.privkey_from
  54     def using_helper(self):
  55         return False
  56     def get_size(self):
  57         return "-NA-"
  58     def get_status(self):
  59         return self.status
  60     def get_progress(self):
  61         return self.progress
  62     def get_active(self):
  63         return self.active
  64     def get_counter(self):
  65         return self.counter
  66
  67     def set_storage_index(self, si):
  68         self.storage_index = si
  69     def set_mode(self, mode):
  70         self.mode = mode
  71     def set_privkey_from(self, peerid):
  72         self.privkey_from = peerid
  73     def set_status(self, status):
  74         self.status = status
  75     def set_progress(self, value):
  76         self.progress = value
  77     def set_active(self, value):
  78         self.active = value
  79     def set_finished(self, when):
  80         self.finished = when
  81
  82 class ServerMap:
  83     """I record the placement of mutable shares.
  84
  85     This object records which shares (of various versions) are located on
  86     which servers.
  87
  88     One purpose I serve is to inform callers about which versions of the
  89     mutable file are recoverable and 'current'.
  90
  91     A second purpose is to serve as a state marker for test-and-set
  92     operations. I am passed out of retrieval operations and back into publish
  93     operations, which means 'publish this new version, but only if nothing
  94     has changed since I last retrieved this data'. This reduces the chances
  95     of clobbering a simultaneous (uncoordinated) write.
  96
  97     @ivar servermap: a dictionary, mapping a (peerid, shnum) tuple to a
  98                      (versionid, timestamp) tuple. Each 'versionid' is a
  99                      tuple of (seqnum, root_hash, IV, segsize, datalength,
 100                      k, N, signed_prefix, offsets)
 101
 102     @ivar connections: maps peerid to a RemoteReference
 103
 104     @ivar bad_shares: dict with keys of (peerid, shnum) tuples, describing
 105                       shares that I should ignore (because a previous user of
 106                       the servermap determined that they were invalid). The
 107                       updater only locates a certain number of shares: if
 108                       some of these turn out to have integrity problems and
 109                       are unusable, the caller will need to mark those shares
 110                       as bad, then re-update the servermap, then try again.
 111                       The dict maps (peerid, shnum) tuple to old checkstring.
 112     """
 113
 114     def __init__(self):
 115         self.servermap = {}
 116         self.connections = {}
 117         self.unreachable_peers = set() # peerids that didn't respond to queries
 118         self.reachable_peers = set() # peerids that did respond to queries
 119         self.problems = [] # mostly for debugging
 120         self.bad_shares = {} # maps (peerid,shnum) to old checkstring
 121         self.last_update_mode = None
 122         self.last_update_time = 0
 123
 124     def copy(self):
 125         s = ServerMap()
 126         s.servermap = self.servermap.copy() # tuple->tuple
 127         s.connections = self.connections.copy() # str->RemoteReference
 128         s.unreachable_peers = set(self.unreachable_peers)
 129         s.reachable_peers = set(self.reachable_peers)
 130         s.problems = self.problems[:]
 131         s.bad_shares = self.bad_shares.copy() # tuple->str
 132         s.last_update_mode = self.last_update_mode
 133         s.last_update_time = self.last_update_time
 134         return s
 135
 136     def mark_bad_share(self, peerid, shnum, checkstring):
 137         """This share was found to be bad, either in the checkstring or
 138         signature (detected during mapupdate), or deeper in the share
 139         (detected at retrieve time). Remove it from our list of useful
 140         shares, and remember that it is bad so we don't add it back again
 141         later. We record the share's old checkstring (which might be
 142         corrupted or badly signed) so that a repair operation can do the
 143         test-and-set using it as a reference.
 144         """
 145         key = (peerid, shnum) # record checkstring
 146         self.bad_shares[key] = checkstring
 147         self.servermap.pop(key, None)
 148
 149     def add_new_share(self, peerid, shnum, verinfo, timestamp):
 150         """We've written a new share out, replacing any that was there
 151         before."""
 152         key = (peerid, shnum)
 153         self.bad_shares.pop(key, None)
 154         self.servermap[key] = (verinfo, timestamp)
 155
 156     def dump(self, out=sys.stdout):
 157         print >>out, "servermap:"
 158
 159         for ( (peerid, shnum), (verinfo, timestamp) ) in self.servermap.items():
 160             (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
 161              offsets_tuple) = verinfo
 162             print >>out, ("[%s]: sh#%d seq%d-%s %d-of-%d len%d" %
 163                           (idlib.shortnodeid_b2a(peerid), shnum,
 164                            seqnum, base32.b2a(root_hash)[:4], k, N,
 165                            datalength))
 166         if self.problems:
 167             print >>out, "%d PROBLEMS" % len(self.problems)
 168             for f in self.problems:
 169                 print >>out, str(f)
 170         return out
 171
 172     def all_peers(self):
 173         return set([peerid
 174                     for (peerid, shnum)
 175                     in self.servermap])
 176
 177     def all_peers_for_version(self, verinfo):
 178         """Return a set of peerids that hold shares for the given version."""
 179         return set([peerid
 180                     for ( (peerid, shnum), (verinfo2, timestamp) )
 181                     in self.servermap.items()
 182                     if verinfo == verinfo2])
 183
 184     def make_sharemap(self):
 185         """Return a dict that maps shnum to a set of peerds that hold it."""
 186         sharemap = DictOfSets()
 187         for (peerid, shnum) in self.servermap:
 188             sharemap.add(shnum, peerid)
 189         return sharemap
 190
 191     def make_versionmap(self):
 192         """Return a dict that maps versionid to sets of (shnum, peerid,
 193         timestamp) tuples."""
 194         versionmap = DictOfSets()
 195         for ( (peerid, shnum), (verinfo, timestamp) ) in self.servermap.items():
 196             versionmap.add(verinfo, (shnum, peerid, timestamp))
 197         return versionmap
 198
 199     def shares_on_peer(self, peerid):
 200         return set([shnum
 201                     for (s_peerid, shnum)
 202                     in self.servermap
 203                     if s_peerid == peerid])
 204
 205     def version_on_peer(self, peerid, shnum):
 206         key = (peerid, shnum)
 207         if key in self.servermap:
 208             (verinfo, timestamp) = self.servermap[key]
 209             return verinfo
 210         return None
 211
 212     def shares_available(self):
 213         """Return a dict that maps verinfo to tuples of
 214         (num_distinct_shares, k, N) tuples."""
 215         versionmap = self.make_versionmap()
 216         all_shares = {}
 217         for verinfo, shares in versionmap.items():
 218             s = set()
 219             for (shnum, peerid, timestamp) in shares:
 220                 s.add(shnum)
 221             (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
 222              offsets_tuple) = verinfo
 223             all_shares[verinfo] = (len(s), k, N)
 224         return all_shares
 225
 226     def highest_seqnum(self):
 227         available = self.shares_available()
 228         seqnums = [verinfo[0]
 229                    for verinfo in available.keys()]
 230         seqnums.append(0)
 231         return max(seqnums)
 232
 233     def summarize_version(self, verinfo):
 234         """Take a versionid, return a string that describes it."""
 235         (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
 236          offsets_tuple) = verinfo
 237         return "seq%d-%s" % (seqnum, base32.b2a(root_hash)[:4])
 238
 239     def summarize_versions(self):
 240         """Return a string describing which versions we know about."""
 241         versionmap = self.make_versionmap()
 242         bits = []
 243         for (verinfo, shares) in versionmap.items():
 244             vstr = self.summarize_version(verinfo)
 245             shnums = set([shnum for (shnum, peerid, timestamp) in shares])
 246             bits.append("%d*%s" % (len(shnums), vstr))
 247         return "/".join(bits)
 248
 249     def recoverable_versions(self):
 250         """Return a set of versionids, one for each version that is currently
 251         recoverable."""
 252         versionmap = self.make_versionmap()
 253
 254         recoverable_versions = set()
 255         for (verinfo, shares) in versionmap.items():
 256             (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
 257              offsets_tuple) = verinfo
 258             shnums = set([shnum for (shnum, peerid, timestamp) in shares])
 259             if len(shnums) >= k:
 260                 # this one is recoverable
 261                 recoverable_versions.add(verinfo)
 262
 263         return recoverable_versions
 264
 265     def unrecoverable_versions(self):
 266         """Return a set of versionids, one for each version that is currently
 267         unrecoverable."""
 268         versionmap = self.make_versionmap()
 269
 270         unrecoverable_versions = set()
 271         for (verinfo, shares) in versionmap.items():
 272             (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
 273              offsets_tuple) = verinfo
 274             shnums = set([shnum for (shnum, peerid, timestamp) in shares])
 275             if len(shnums) < k:
 276                 unrecoverable_versions.add(verinfo)
 277
 278         return unrecoverable_versions
 279
 280     def best_recoverable_version(self):
 281         """Return a single versionid, for the so-called 'best' recoverable
 282         version. Sequence number is the primary sort criteria, followed by
 283         root hash. Returns None if there are no recoverable versions."""
 284         recoverable = list(self.recoverable_versions())
 285         recoverable.sort()
 286         if recoverable:
 287             return recoverable[-1]
 288         return None
 289
 290     def size_of_version(self, verinfo):
 291         """Given a versionid (perhaps returned by best_recoverable_version),
 292         return the size of the file in bytes."""
 293         (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
 294          offsets_tuple) = verinfo
 295         return datalength
 296
 297     def unrecoverable_newer_versions(self):
 298         # Return a dict of versionid -> health, for versions that are
 299         # unrecoverable and have later seqnums than any recoverable versions.
 300         # These indicate that a write will lose data.
 301         versionmap = self.make_versionmap()
 302         healths = {} # maps verinfo to (found,k)
 303         unrecoverable = set()
 304         highest_recoverable_seqnum = -1
 305         for (verinfo, shares) in versionmap.items():
 306             (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
 307              offsets_tuple) = verinfo
 308             shnums = set([shnum for (shnum, peerid, timestamp) in shares])
 309             healths[verinfo] = (len(shnums),k)
 310             if len(shnums) < k:
 311                 unrecoverable.add(verinfo)
 312             else:
 313                 highest_recoverable_seqnum = max(seqnum,
 314                                                  highest_recoverable_seqnum)
 315
 316         newversions = {}
 317         for verinfo in unrecoverable:
 318             (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
 319              offsets_tuple) = verinfo
 320             if seqnum > highest_recoverable_seqnum:
 321                 newversions[verinfo] = healths[verinfo]
 322
 323         return newversions
 324
 325
 326     def needs_merge(self):
 327         # return True if there are multiple recoverable versions with the
 328         # same seqnum, meaning that MutableFileNode.read_best_version is not
 329         # giving you the whole story, and that using its data to do a
 330         # subsequent publish will lose information.
 331         recoverable_seqnums = [verinfo[0]
 332                                for verinfo in self.recoverable_versions()]
 333         for seqnum in recoverable_seqnums:
 334             if recoverable_seqnums.count(seqnum) > 1:
 335                 return True
 336         return False
 337
 338
 339 class ServermapUpdater:
 340     def __init__(self, filenode, monitor, servermap, mode=MODE_READ,
 341                  add_lease=False):
 342         """I update a servermap, locating a sufficient number of useful
 343         shares and remembering where they are located.
 344
 345         """
 346
 347         self._node = filenode
 348         self._monitor = monitor
 349         self._servermap = servermap
 350         self.mode = mode
 351         self._add_lease = add_lease
 352         self._running = True
 353
 354         self._storage_index = filenode.get_storage_index()
 355         self._last_failure = None
 356
 357         self._status = UpdateStatus()
 358         self._status.set_storage_index(self._storage_index)
 359         self._status.set_progress(0.0)
 360         self._status.set_mode(mode)
 361
 362         self._servers_responded = set()
 363
 364         # how much data should we read?
 365         #  * if we only need the checkstring, then [0:75]
 366         #  * if we need to validate the checkstring sig, then [543ish:799ish]
 367         #  * if we need the verification key, then [107:436ish]
 368         #   * the offset table at [75:107] tells us about the 'ish'
 369         #  * if we need the encrypted private key, we want [-1216ish:]
 370         #   * but we can't read from negative offsets
 371         #   * the offset table tells us the 'ish', also the positive offset
 372         # A future version of the SMDF slot format should consider using
 373         # fixed-size slots so we can retrieve less data. For now, we'll just
 374         # read 2000 bytes, which also happens to read enough actual data to
 375         # pre-fetch a 9-entry dirnode.
 376         self._read_size = 4000
 377         if mode == MODE_CHECK:
 378             # we use unpack_prefix_and_signature, so we need 1k
 379             self._read_size = 1000
 380         self._need_privkey = False
 381         if mode == MODE_WRITE and not self._node._privkey:
 382             self._need_privkey = True
 383         # check+repair: repair requires the privkey, so if we didn't happen
 384         # to ask for it during the check, we'll have problems doing the
 385         # publish.
 386
 387         prefix = si_b2a(self._storage_index)[:5]
 388         self._log_number = log.msg(format="SharemapUpdater(%(si)s): starting (%(mode)s)",
 389                                    si=prefix, mode=mode)
 390
 391     def get_status(self):
 392         return self._status
 393
 394     def log(self, *args, **kwargs):
 395         if "parent" not in kwargs:
 396             kwargs["parent"] = self._log_number
 397         if "facility" not in kwargs:
 398             kwargs["facility"] = "tahoe.mutable.mapupdate"
 399         return log.msg(*args, **kwargs)
 400
 401     def update(self):
 402         """Update the servermap to reflect current conditions. Returns a
 403         Deferred that fires with the servermap once the update has finished."""
 404         self._started = time.time()
 405         self._status.set_active(True)
 406
 407         # self._valid_versions is a set of validated verinfo tuples. We just
 408         # use it to remember which versions had valid signatures, so we can
 409         # avoid re-checking the signatures for each share.
 410         self._valid_versions = set()
 411
 412         # self.versionmap maps verinfo tuples to sets of (shnum, peerid,
 413         # timestamp) tuples. This is used to figure out which versions might
 414         # be retrievable, and to make the eventual data download faster.
 415         self.versionmap = DictOfSets()
 416
 417         self._done_deferred = defer.Deferred()
 418
 419         # first, which peers should be talk to? Any that were in our old
 420         # servermap, plus "enough" others.
 421
 422         self._queries_completed = 0
 423
 424         client = self._node._client
 425         full_peerlist = client.get_permuted_peers("storage",
 426                                                   self._node._storage_index)
 427         self.full_peerlist = full_peerlist # for use later, immutable
 428         self.extra_peers = full_peerlist[:] # peers are removed as we use them
 429         self._good_peers = set() # peers who had some shares
 430         self._empty_peers = set() # peers who don't have any shares
 431         self._bad_peers = set() # peers to whom our queries failed
 432
 433         k = self._node.get_required_shares()
 434         if k is None:
 435             # make a guess
 436             k = 3
 437         N = self._node.get_required_shares()
 438         if N is None:
 439             N = 10
 440         self.EPSILON = k
 441         # we want to send queries to at least this many peers (although we
 442         # might not wait for all of their answers to come back)
 443         self.num_peers_to_query = k + self.EPSILON
 444
 445         if self.mode == MODE_CHECK:
 446             initial_peers_to_query = dict(full_peerlist)
 447             must_query = set(initial_peers_to_query.keys())
 448             self.extra_peers = []
 449         elif self.mode == MODE_WRITE:
 450             # we're planning to replace all the shares, so we want a good
 451             # chance of finding them all. We will keep searching until we've
 452             # seen epsilon that don't have a share.
 453             self.num_peers_to_query = N + self.EPSILON
 454             initial_peers_to_query, must_query = self._build_initial_querylist()
 455             self.required_num_empty_peers = self.EPSILON
 456
 457             # TODO: arrange to read lots of data from k-ish servers, to avoid
 458             # the extra round trip required to read large directories. This
 459             # might also avoid the round trip required to read the encrypted
 460             # private key.
 461
 462         else:
 463             initial_peers_to_query, must_query = self._build_initial_querylist()
 464
 465         # this is a set of peers that we are required to get responses from:
 466         # they are peers who used to have a share, so we need to know where
 467         # they currently stand, even if that means we have to wait for a
 468         # silently-lost TCP connection to time out. We remove peers from this
 469         # set as we get responses.
 470         self._must_query = must_query
 471
 472         # now initial_peers_to_query contains the peers that we should ask,
 473         # self.must_query contains the peers that we must have heard from
 474         # before we can consider ourselves finished, and self.extra_peers
 475         # contains the overflow (peers that we should tap if we don't get
 476         # enough responses)
 477
 478         self._send_initial_requests(initial_peers_to_query)
 479         self._status.timings["initial_queries"] = time.time() - self._started
 480         return self._done_deferred
 481
 482     def _build_initial_querylist(self):
 483         initial_peers_to_query = {}
 484         must_query = set()
 485         for peerid in self._servermap.all_peers():
 486             ss = self._servermap.connections[peerid]
 487             # we send queries to everyone who was already in the sharemap
 488             initial_peers_to_query[peerid] = ss
 489             # and we must wait for responses from them
 490             must_query.add(peerid)
 491
 492         while ((self.num_peers_to_query > len(initial_peers_to_query))
 493                and self.extra_peers):
 494             (peerid, ss) = self.extra_peers.pop(0)
 495             initial_peers_to_query[peerid] = ss
 496
 497         return initial_peers_to_query, must_query
 498
 499     def _send_initial_requests(self, peerlist):
 500         self._status.set_status("Sending %d initial queries" % len(peerlist))
 501         self._queries_outstanding = set()
 502         self._sharemap = DictOfSets() # shnum -> [(peerid, seqnum, R)..]
 503         dl = []
 504         for (peerid, ss) in peerlist.items():
 505             self._queries_outstanding.add(peerid)
 506             self._do_query(ss, peerid, self._storage_index, self._read_size)
 507
 508         if not peerlist:
 509             # there is nobody to ask, so we need to short-circuit the state
 510             # machine.
 511             d = defer.maybeDeferred(self._check_for_done, None)
 512             d.addErrback(self._fatal_error)
 513
 514         # control flow beyond this point: state machine. Receiving responses
 515         # from queries is the input. We might send out more queries, or we
 516         # might produce a result.
 517         return None
 518
 519     def _do_query(self, ss, peerid, storage_index, readsize):
 520         self.log(format="sending query to [%(peerid)s], readsize=%(readsize)d",
 521                  peerid=idlib.shortnodeid_b2a(peerid),
 522                  readsize=readsize,
 523                  level=log.NOISY)
 524         self._servermap.connections[peerid] = ss
 525         started = time.time()
 526         self._queries_outstanding.add(peerid)
 527         d = self._do_read(ss, peerid, storage_index, [], [(0, readsize)])
 528         d.addCallback(self._got_results, peerid, readsize, (ss, storage_index),
 529                       started)
 530         d.addErrback(self._query_failed, peerid)
 531         # errors that aren't handled by _query_failed (and errors caused by
 532         # _query_failed) get logged, but we still want to check for doneness.
 533         d.addErrback(log.err)
 534         d.addBoth(self._check_for_done)
 535         d.addErrback(self._fatal_error)
 536         return d
 537
 538     def _do_read(self, ss, peerid, storage_index, shnums, readv):
 539         d = ss.callRemote("slot_readv", storage_index, shnums, readv)
 540         if self._add_lease:
 541             renew_secret = self._node.get_renewal_secret(peerid)
 542             cancel_secret = self._node.get_cancel_secret(peerid)
 543             d2 = ss.callRemote("add_lease", storage_index,
 544                                renew_secret, cancel_secret)
 545             dl = defer.DeferredList([d, d2], consumeErrors=True)
 546             def _done(res):
 547                 [(readv_success, readv_result),
 548                  (addlease_success, addlease_result)] = res
 549                 # ignore remote IndexError on the add_lease call. Propagate
 550                 # local errors and remote non-IndexErrors
 551                 if addlease_success:
 552                     return readv_result
 553                 if not addlease_result.check(RemoteException):
 554                     # Propagate local errors
 555                     return addlease_result
 556                 if addlease_result.value.failure.check(IndexError):
 557                     # tahoe=1.3.0 raised IndexError on non-existant
 558                     # buckets, which we ignore
 559                     return readv_result
 560                 # propagate remote errors that aren't IndexError, including
 561                 # the unfortunate internal KeyError bug that <1.3.0 had.
 562                 return addlease_result
 563             dl.addCallback(_done)
 564             return dl
 565         return d
 566
 567     def _got_results(self, datavs, peerid, readsize, stuff, started):
 568         lp = self.log(format="got result from [%(peerid)s], %(numshares)d shares",
 569                       peerid=idlib.shortnodeid_b2a(peerid),
 570                       numshares=len(datavs),
 571                       level=log.NOISY)
 572         now = time.time()
 573         elapsed = now - started
 574         self._queries_outstanding.discard(peerid)
 575         self._servermap.reachable_peers.add(peerid)
 576         self._must_query.discard(peerid)
 577         self._queries_completed += 1
 578         if not self._running:
 579             self.log("but we're not running, so we'll ignore it", parent=lp,
 580                      level=log.NOISY)
 581             self._status.add_per_server_time(peerid, "late", started, elapsed)
 582             return
 583         self._status.add_per_server_time(peerid, "query", started, elapsed)
 584
 585         if datavs:
 586             self._good_peers.add(peerid)
 587         else:
 588             self._empty_peers.add(peerid)
 589
 590         last_verinfo = None
 591         last_shnum = None
 592         for shnum,datav in datavs.items():
 593             data = datav[0]
 594             try:
 595                 verinfo = self._got_results_one_share(shnum, data, peerid, lp)
 596                 last_verinfo = verinfo
 597                 last_shnum = shnum
 598                 self._node._cache.add(verinfo, shnum, 0, data, now)
 599             except CorruptShareError, e:
 600                 # log it and give the other shares a chance to be processed
 601                 f = failure.Failure()
 602                 self.log(format="bad share: %(f_value)s", f_value=str(f.value),
 603                          failure=f, parent=lp, level=log.WEIRD, umid="h5llHg")
 604                 self.notify_server_corruption(peerid, shnum, str(e))
 605                 self._bad_peers.add(peerid)
 606                 self._last_failure = f
 607                 checkstring = data[:SIGNED_PREFIX_LENGTH]
 608                 self._servermap.mark_bad_share(peerid, shnum, checkstring)
 609                 self._servermap.problems.append(f)
 610                 pass
 611
 612         self._status.timings["cumulative_verify"] += (time.time() - now)
 613
 614         if self._need_privkey and last_verinfo:
 615             # send them a request for the privkey. We send one request per
 616             # server.
 617             lp2 = self.log("sending privkey request",
 618                            parent=lp, level=log.NOISY)
 619             (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
 620              offsets_tuple) = last_verinfo
 621             o = dict(offsets_tuple)
 622
 623             self._queries_outstanding.add(peerid)
 624             readv = [ (o['enc_privkey'], (o['EOF'] - o['enc_privkey'])) ]
 625             ss = self._servermap.connections[peerid]
 626             privkey_started = time.time()
 627             d = self._do_read(ss, peerid, self._storage_index,
 628                               [last_shnum], readv)
 629             d.addCallback(self._got_privkey_results, peerid, last_shnum,
 630                           privkey_started, lp2)
 631             d.addErrback(self._privkey_query_failed, peerid, last_shnum, lp2)
 632             d.addErrback(log.err)
 633             d.addCallback(self._check_for_done)
 634             d.addErrback(self._fatal_error)
 635
 636         # all done!
 637         self.log("_got_results done", parent=lp, level=log.NOISY)
 638
 639     def notify_server_corruption(self, peerid, shnum, reason):
 640         ss = self._servermap.connections[peerid]
 641         ss.callRemoteOnly("advise_corrupt_share",
 642                           "mutable", self._storage_index, shnum, reason)
 643
 644     def _got_results_one_share(self, shnum, data, peerid, lp):
 645         self.log(format="_got_results: got shnum #%(shnum)d from peerid %(peerid)s",
 646                  shnum=shnum,
 647                  peerid=idlib.shortnodeid_b2a(peerid),
 648                  level=log.NOISY,
 649                  parent=lp)
 650
 651         # this might raise NeedMoreDataError, if the pubkey and signature
 652         # live at some weird offset. That shouldn't happen, so I'm going to
 653         # treat it as a bad share.
 654         (seqnum, root_hash, IV, k, N, segsize, datalength,
 655          pubkey_s, signature, prefix) = unpack_prefix_and_signature(data)
 656
 657         if not self._node.get_pubkey():
 658             fingerprint = hashutil.ssk_pubkey_fingerprint_hash(pubkey_s)
 659             assert len(fingerprint) == 32
 660             if fingerprint != self._node._fingerprint:
 661                 raise CorruptShareError(peerid, shnum,
 662                                         "pubkey doesn't match fingerprint")
 663             self._node._populate_pubkey(self._deserialize_pubkey(pubkey_s))
 664
 665         if self._need_privkey:
 666             self._try_to_extract_privkey(data, peerid, shnum, lp)
 667
 668         (ig_version, ig_seqnum, ig_root_hash, ig_IV, ig_k, ig_N,
 669          ig_segsize, ig_datalen, offsets) = unpack_header(data)
 670         offsets_tuple = tuple( [(key,value) for key,value in offsets.items()] )
 671
 672         verinfo = (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
 673                    offsets_tuple)
 674
 675         if verinfo not in self._valid_versions:
 676             # it's a new pair. Verify the signature.
 677             valid = self._node._pubkey.verify(prefix, signature)
 678             if not valid:
 679                 raise CorruptShareError(peerid, shnum, "signature is invalid")
 680
 681             # ok, it's a valid verinfo. Add it to the list of validated
 682             # versions.
 683             self.log(" found valid version %d-%s from %s-sh%d: %d-%d/%d/%d"
 684                      % (seqnum, base32.b2a(root_hash)[:4],
 685                         idlib.shortnodeid_b2a(peerid), shnum,
 686                         k, N, segsize, datalength),
 687                      parent=lp)
 688             self._valid_versions.add(verinfo)
 689         # We now know that this is a valid candidate verinfo.
 690
 691         if (peerid, shnum) in self._servermap.bad_shares:
 692             # we've been told that the rest of the data in this share is
 693             # unusable, so don't add it to the servermap.
 694             self.log("but we've been told this is a bad share",
 695                      parent=lp, level=log.UNUSUAL)
 696             return verinfo
 697
 698         # Add the info to our servermap.
 699         timestamp = time.time()
 700         self._servermap.add_new_share(peerid, shnum, verinfo, timestamp)
 701         # and the versionmap
 702         self.versionmap.add(verinfo, (shnum, peerid, timestamp))
 703         return verinfo
 704
 705     def _deserialize_pubkey(self, pubkey_s):
 706         verifier = rsa.create_verifying_key_from_string(pubkey_s)
 707         return verifier
 708
 709     def _try_to_extract_privkey(self, data, peerid, shnum, lp):
 710         try:
 711             r = unpack_share(data)
 712         except NeedMoreDataError, e:
 713             # this share won't help us. oh well.
 714             offset = e.encprivkey_offset
 715             length = e.encprivkey_length
 716             self.log("shnum %d on peerid %s: share was too short (%dB) "
 717                      "to get the encprivkey; [%d:%d] ought to hold it" %
 718                      (shnum, idlib.shortnodeid_b2a(peerid), len(data),
 719                       offset, offset+length),
 720                      parent=lp)
 721             # NOTE: if uncoordinated writes are taking place, someone might
 722             # change the share (and most probably move the encprivkey) before
 723             # we get a chance to do one of these reads and fetch it. This
 724             # will cause us to see a NotEnoughSharesError(unable to fetch
 725             # privkey) instead of an UncoordinatedWriteError . This is a
 726             # nuisance, but it will go away when we move to DSA-based mutable
 727             # files (since the privkey will be small enough to fit in the
 728             # write cap).
 729
 730             return
 731
 732         (seqnum, root_hash, IV, k, N, segsize, datalen,
 733          pubkey, signature, share_hash_chain, block_hash_tree,
 734          share_data, enc_privkey) = r
 735
 736         return self._try_to_validate_privkey(enc_privkey, peerid, shnum, lp)
 737
 738     def _try_to_validate_privkey(self, enc_privkey, peerid, shnum, lp):
 739
 740         alleged_privkey_s = self._node._decrypt_privkey(enc_privkey)
 741         alleged_writekey = hashutil.ssk_writekey_hash(alleged_privkey_s)
 742         if alleged_writekey != self._node.get_writekey():
 743             self.log("invalid privkey from %s shnum %d" %
 744                      (idlib.nodeid_b2a(peerid)[:8], shnum),
 745                      parent=lp, level=log.WEIRD, umid="aJVccw")
 746             return
 747
 748         # it's good
 749         self.log("got valid privkey from shnum %d on peerid %s" %
 750                  (shnum, idlib.shortnodeid_b2a(peerid)),
 751                  parent=lp)
 752         privkey = rsa.create_signing_key_from_string(alleged_privkey_s)
 753         self._node._populate_encprivkey(enc_privkey)
 754         self._node._populate_privkey(privkey)
 755         self._need_privkey = False
 756         self._status.set_privkey_from(peerid)
 757
 758
 759     def _query_failed(self, f, peerid):
 760         if not self._running:
 761             return
 762         level = log.WEIRD
 763         if f.check(DeadReferenceError):
 764             level = log.UNUSUAL
 765         self.log(format="error during query: %(f_value)s",
 766                  f_value=str(f.value), failure=f,
 767                  level=level, umid="IHXuQg")
 768         self._must_query.discard(peerid)
 769         self._queries_outstanding.discard(peerid)
 770         self._bad_peers.add(peerid)
 771         self._servermap.problems.append(f)
 772         # a peerid could be in both ServerMap.reachable_peers and
 773         # .unreachable_peers if they responded to our query, but then an
 774         # exception was raised in _got_results.
 775         self._servermap.unreachable_peers.add(peerid)
 776         self._queries_completed += 1
 777         self._last_failure = f
 778
 779     def _got_privkey_results(self, datavs, peerid, shnum, started, lp):
 780         now = time.time()
 781         elapsed = now - started
 782         self._status.add_per_server_time(peerid, "privkey", started, elapsed)
 783         self._queries_outstanding.discard(peerid)
 784         if not self._need_privkey:
 785             return
 786         if shnum not in datavs:
 787             self.log("privkey wasn't there when we asked it",
 788                      level=log.WEIRD, umid="VA9uDQ")
 789             return
 790         datav = datavs[shnum]
 791         enc_privkey = datav[0]
 792         self._try_to_validate_privkey(enc_privkey, peerid, shnum, lp)
 793
 794     def _privkey_query_failed(self, f, peerid, shnum, lp):
 795         self._queries_outstanding.discard(peerid)
 796         if not self._running:
 797             return
 798         level = log.WEIRD
 799         if f.check(DeadReferenceError):
 800             level = log.UNUSUAL
 801         self.log(format="error during privkey query: %(f_value)s",
 802                  f_value=str(f.value), failure=f,
 803                  parent=lp, level=level, umid="McoJ5w")
 804         self._servermap.problems.append(f)
 805         self._last_failure = f
 806
 807     def _check_for_done(self, res):
 808         # exit paths:
 809         #  return self._send_more_queries(outstanding) : send some more queries
 810         #  return self._done() : all done
 811         #  return : keep waiting, no new queries
 812
 813         lp = self.log(format=("_check_for_done, mode is '%(mode)s', "
 814                               "%(outstanding)d queries outstanding, "
 815                               "%(extra)d extra peers available, "
 816                               "%(must)d 'must query' peers left, "
 817                               "need_privkey=%(need_privkey)s"
 818                               ),
 819                       mode=self.mode,
 820                       outstanding=len(self._queries_outstanding),
 821                       extra=len(self.extra_peers),
 822                       must=len(self._must_query),
 823                       need_privkey=self._need_privkey,
 824                       level=log.NOISY,
 825                       )
 826
 827         if not self._running:
 828             self.log("but we're not running", parent=lp, level=log.NOISY)
 829             return
 830
 831         if self._must_query:
 832             # we are still waiting for responses from peers that used to have
 833             # a share, so we must continue to wait. No additional queries are
 834             # required at this time.
 835             self.log("%d 'must query' peers left" % len(self._must_query),
 836                      level=log.NOISY, parent=lp)
 837             return
 838
 839         if (not self._queries_outstanding and not self.extra_peers):
 840             # all queries have retired, and we have no peers left to ask. No
 841             # more progress can be made, therefore we are done.
 842             self.log("all queries are retired, no extra peers: done",
 843                      parent=lp)
 844             return self._done()
 845
 846         recoverable_versions = self._servermap.recoverable_versions()
 847         unrecoverable_versions = self._servermap.unrecoverable_versions()
 848
 849         # what is our completion policy? how hard should we work?
 850
 851         if self.mode == MODE_ANYTHING:
 852             if recoverable_versions:
 853                 self.log("%d recoverable versions: done"
 854                          % len(recoverable_versions),
 855                          parent=lp)
 856                 return self._done()
 857
 858         if self.mode == MODE_CHECK:
 859             # we used self._must_query, and we know there aren't any
 860             # responses still waiting, so that means we must be done
 861             self.log("done", parent=lp)
 862             return self._done()
 863
 864         MAX_IN_FLIGHT = 5
 865         if self.mode == MODE_READ:
 866             # if we've queried k+epsilon servers, and we see a recoverable
 867             # version, and we haven't seen any unrecoverable higher-seqnum'ed
 868             # versions, then we're done.
 869
 870             if self._queries_completed < self.num_peers_to_query:
 871                 self.log(format="%(completed)d completed, %(query)d to query: need more",
 872                          completed=self._queries_completed,
 873                          query=self.num_peers_to_query,
 874                          level=log.NOISY, parent=lp)
 875                 return self._send_more_queries(MAX_IN_FLIGHT)
 876             if not recoverable_versions:
 877                 self.log("no recoverable versions: need more",
 878                          level=log.NOISY, parent=lp)
 879                 return self._send_more_queries(MAX_IN_FLIGHT)
 880             highest_recoverable = max(recoverable_versions)
 881             highest_recoverable_seqnum = highest_recoverable[0]
 882             for unrec_verinfo in unrecoverable_versions:
 883                 if unrec_verinfo[0] > highest_recoverable_seqnum:
 884                     # there is evidence of a higher-seqnum version, but we
 885                     # don't yet see enough shares to recover it. Try harder.
 886                     # TODO: consider sending more queries.
 887                     # TODO: consider limiting the search distance
 888                     self.log("evidence of higher seqnum: need more",
 889                              level=log.UNUSUAL, parent=lp)
 890                     return self._send_more_queries(MAX_IN_FLIGHT)
 891             # all the unrecoverable versions were old or concurrent with a
 892             # recoverable version. Good enough.
 893             self.log("no higher-seqnum: done", parent=lp)
 894             return self._done()
 895
 896         if self.mode == MODE_WRITE:
 897             # we want to keep querying until we've seen a few that don't have
 898             # any shares, to be sufficiently confident that we've seen all
 899             # the shares. This is still less work than MODE_CHECK, which asks
 900             # every server in the world.
 901
 902             if not recoverable_versions:
 903                 self.log("no recoverable versions: need more", parent=lp,
 904                          level=log.NOISY)
 905                 return self._send_more_queries(MAX_IN_FLIGHT)
 906
 907             last_found = -1
 908             last_not_responded = -1
 909             num_not_responded = 0
 910             num_not_found = 0
 911             states = []
 912             found_boundary = False
 913
 914             for i,(peerid,ss) in enumerate(self.full_peerlist):
 915                 if peerid in self._bad_peers:
 916                     # query failed
 917                     states.append("x")
 918                     #self.log("loop [%s]: x" % idlib.shortnodeid_b2a(peerid))
 919                 elif peerid in self._empty_peers:
 920                     # no shares
 921                     states.append("0")
 922                     #self.log("loop [%s]: 0" % idlib.shortnodeid_b2a(peerid))
 923                     if last_found != -1:
 924                         num_not_found += 1
 925                         if num_not_found >= self.EPSILON:
 926                             self.log("found our boundary, %s" %
 927                                      "".join(states),
 928                                      parent=lp, level=log.NOISY)
 929                             found_boundary = True
 930                             break
 931
 932                 elif peerid in self._good_peers:
 933                     # yes shares
 934                     states.append("1")
 935                     #self.log("loop [%s]: 1" % idlib.shortnodeid_b2a(peerid))
 936                     last_found = i
 937                     num_not_found = 0
 938                 else:
 939                     # not responded yet
 940                     states.append("?")
 941                     #self.log("loop [%s]: ?" % idlib.shortnodeid_b2a(peerid))
 942                     last_not_responded = i
 943                     num_not_responded += 1
 944
 945             if found_boundary:
 946                 # we need to know that we've gotten answers from
 947                 # everybody to the left of here
 948                 if last_not_responded == -1:
 949                     # we're done
 950                     self.log("have all our answers",
 951                              parent=lp, level=log.NOISY)
 952                     # .. unless we're still waiting on the privkey
 953                     if self._need_privkey:
 954                         self.log("but we're still waiting for the privkey",
 955                                  parent=lp, level=log.NOISY)
 956                         # if we found the boundary but we haven't yet found
 957                         # the privkey, we may need to look further. If
 958                         # somehow all the privkeys were corrupted (but the
 959                         # shares were readable), then this is likely to do an
 960                         # exhaustive search.
 961                         return self._send_more_queries(MAX_IN_FLIGHT)
 962                     return self._done()
 963                 # still waiting for somebody
 964                 return self._send_more_queries(num_not_responded)
 965
 966             # if we hit here, we didn't find our boundary, so we're still
 967             # waiting for peers
 968             self.log("no boundary yet, %s" % "".join(states), parent=lp,
 969                      level=log.NOISY)
 970             return self._send_more_queries(MAX_IN_FLIGHT)
 971
 972         # otherwise, keep up to 5 queries in flight. TODO: this is pretty
 973         # arbitrary, really I want this to be something like k -
 974         # max(known_version_sharecounts) + some extra
 975         self.log("catchall: need more", parent=lp, level=log.NOISY)
 976         return self._send_more_queries(MAX_IN_FLIGHT)
 977
 978     def _send_more_queries(self, num_outstanding):
 979         more_queries = []
 980
 981         while True:
 982             self.log(format=" there are %(outstanding)d queries outstanding",
 983                      outstanding=len(self._queries_outstanding),
 984                      level=log.NOISY)
 985             active_queries = len(self._queries_outstanding) + len(more_queries)
 986             if active_queries >= num_outstanding:
 987                 break
 988             if not self.extra_peers:
 989                 break
 990             more_queries.append(self.extra_peers.pop(0))
 991
 992         self.log(format="sending %(more)d more queries: %(who)s",
 993                  more=len(more_queries),
 994                  who=" ".join(["[%s]" % idlib.shortnodeid_b2a(peerid)
 995                                for (peerid,ss) in more_queries]),
 996                  level=log.NOISY)
 997
 998         for (peerid, ss) in more_queries:
 999             self._do_query(ss, peerid, self._storage_index, self._read_size)
1000             # we'll retrigger when those queries come back
1001
1002     def _done(self):
1003         if not self._running:
1004             return
1005         self._running = False
1006         now = time.time()
1007         elapsed = now - self._started
1008         self._status.set_finished(now)
1009         self._status.timings["total"] = elapsed
1010         self._status.set_progress(1.0)
1011         self._status.set_status("Done")
1012         self._status.set_active(False)
1013
1014         self._servermap.last_update_mode = self.mode
1015         self._servermap.last_update_time = self._started
1016         # the servermap will not be touched after this
1017         self.log("servermap: %s" % self._servermap.summarize_versions())
1018         eventually(self._done_deferred.callback, self._servermap)
1019
1020     def _fatal_error(self, f):
1021         self.log("fatal error", failure=f, level=log.WEIRD, umid="1cNvlw")
1022         self._done_deferred.errback(f)
1023
1024