6 from zope.interface import implements
7 from twisted.internet import defer
9 from allmydata import uri
10 from twisted.internet.interfaces import IConsumer
11 from allmydata.interfaces import IImmutableFileNode, IUploadResults
12 from allmydata.util import consumer
13 from allmydata.check_results import CheckResults, CheckAndRepairResults
14 from allmydata.util.dictutil import DictOfSets
15 from pycryptopp.cipher.aes import AES
18 from allmydata.immutable.checker import Checker
19 from allmydata.immutable.repairer import Repairer
20 from allmydata.immutable.downloader.node import DownloadNode, \
21 IDownloadStatusHandlingConsumer
22 from allmydata.immutable.downloader.status import DownloadStatus
24 class CiphertextFileNode:
25 def __init__(self, verifycap, storage_broker, secret_holder,
27 assert isinstance(verifycap, uri.CHKFileVerifierURI)
28 self._verifycap = verifycap
29 self._storage_broker = storage_broker
30 self._secret_holder = secret_holder
31 self._terminator = terminator
32 self._history = history
33 self._download_status = None
34 self._node = None # created lazily, on read()
36 def _maybe_create_download_node(self):
37 if not self._download_status:
38 ds = DownloadStatus(self._verifycap.storage_index,
41 self._history.add_download(ds)
42 self._download_status = ds
43 if self._node is None:
44 self._node = DownloadNode(self._verifycap, self._storage_broker,
47 self._history, self._download_status)
49 def read(self, consumer, offset=0, size=None):
50 """I am the main entry point, from which FileNode.read() can get
51 data. I feed the consumer with the desired range of ciphertext. I
52 return a Deferred that fires (with the consumer) when the read is
54 self._maybe_create_download_node()
55 return self._node.read(consumer, offset, size)
57 def get_segment(self, segnum):
58 """Begin downloading a segment. I return a tuple (d, c): 'd' is a
59 Deferred that fires with (offset,data) when the desired segment is
60 available, and c is an object on which c.cancel() can be called to
61 disavow interest in the segment (after which 'd' will never fire).
63 You probably need to know the segment size before calling this,
64 unless you want the first few bytes of the file. If you ask for a
65 segment number which turns out to be too large, the Deferred will
66 errback with BadSegmentNumberError.
68 The Deferred fires with the offset of the first byte of the data
69 segment, so that you can call get_segment() before knowing the
70 segment size, and still know which data you received.
72 self._maybe_create_download_node()
73 return self._node.get_segment(segnum)
75 def get_segment_size(self):
76 # return a Deferred that fires with the file's real segment size
77 self._maybe_create_download_node()
78 return self._node.get_segsize()
80 def get_storage_index(self):
81 return self._verifycap.storage_index
82 def get_verify_cap(self):
83 return self._verifycap
85 return self._verifycap.size
87 def raise_error(self):
91 def check_and_repair(self, monitor, verify=False, add_lease=False):
92 verifycap = self._verifycap
93 storage_index = verifycap.storage_index
94 sb = self._storage_broker
95 servers = sb.get_connected_servers()
96 sh = self._secret_holder
98 c = Checker(verifycap=verifycap, servers=servers,
99 verify=verify, add_lease=add_lease, secret_holder=sh,
102 def _maybe_repair(cr):
103 crr = CheckAndRepairResults(storage_index)
104 crr.pre_repair_results = cr
106 crr.post_repair_results = cr
107 return defer.succeed(crr)
109 crr.repair_attempted = True
110 crr.repair_successful = False # until proven successful
111 def _gather_repair_results(ur):
112 assert IUploadResults.providedBy(ur), ur
113 # clone the cr (check results) to form the basis of the
114 # prr (post-repair results)
115 prr = CheckResults(cr.uri, cr.storage_index)
116 prr.data = copy.deepcopy(cr.data)
118 servers_responding = set(prr.data['servers-responding'])
119 sm = prr.data['sharemap']
120 assert isinstance(sm, DictOfSets), sm
121 for shnum, servers in ur.get_sharemap().items():
123 sm.add(shnum, s.get_serverid())
124 servers_responding.add(s.get_serverid())
125 servers_responding = sorted(servers_responding)
126 prr.data['servers-responding'] = servers_responding
127 prr.data['count-shares-good'] = len(sm)
128 good_hosts = len(reduce(set.union, sm.itervalues(), set()))
129 prr.data['count-good-share-hosts'] = good_hosts
130 is_healthy = bool(len(sm) >= verifycap.total_shares)
131 is_recoverable = bool(len(sm) >= verifycap.needed_shares)
132 prr.set_healthy(is_healthy)
133 prr.set_recoverable(is_recoverable)
134 crr.repair_successful = is_healthy
135 prr.set_needs_rebalancing(len(sm) >= verifycap.total_shares)
137 crr.post_repair_results = prr
139 def _repair_error(f):
140 # as with mutable repair, I'm not sure if I want to pass
141 # through a failure or not. TODO
142 crr.repair_successful = False
143 crr.repair_failure = f
145 r = Repairer(self, storage_broker=sb, secret_holder=sh,
148 d.addCallbacks(_gather_repair_results, _repair_error)
151 d.addCallback(_maybe_repair)
154 def check(self, monitor, verify=False, add_lease=False):
155 verifycap = self._verifycap
156 sb = self._storage_broker
157 servers = sb.get_connected_servers()
158 sh = self._secret_holder
160 v = Checker(verifycap=verifycap, servers=servers,
161 verify=verify, add_lease=add_lease, secret_holder=sh,
165 class DecryptingConsumer:
166 """I sit between a CiphertextDownloader (which acts as a Producer) and
167 the real Consumer, decrypting everything that passes by. The real
168 Consumer sees the real Producer, but the Producer sees us instead of the
170 implements(IConsumer, IDownloadStatusHandlingConsumer)
172 def __init__(self, consumer, readkey, offset):
173 self._consumer = consumer
175 self._download_status = None
176 # TODO: pycryptopp CTR-mode needs random-access operations: I want
177 # either a=AES(readkey, offset) or better yet both of:
178 # a=AES(readkey, offset=0)
179 # a.process(ciphertext, offset=xyz)
180 # For now, we fake it with the existing iv= argument.
181 offset_big = offset // 16
182 offset_small = offset % 16
183 iv = binascii.unhexlify("%032x" % offset_big)
184 self._decryptor = AES(readkey, iv=iv)
185 self._decryptor.process("\x00"*offset_small)
187 def set_download_status_read_event(self, read_ev):
188 self._read_ev = read_ev
189 def set_download_status(self, ds):
190 self._download_status = ds
192 def registerProducer(self, producer, streaming):
193 # this passes through, so the real consumer can flow-control the real
194 # producer. Therefore we don't need to provide any IPushProducer
195 # methods. We implement all the IConsumer methods as pass-throughs,
196 # and only intercept write() to perform decryption.
197 self._consumer.registerProducer(producer, streaming)
198 def unregisterProducer(self):
199 self._consumer.unregisterProducer()
200 def write(self, ciphertext):
202 plaintext = self._decryptor.process(ciphertext)
204 elapsed = now() - started
205 self._read_ev.update(0, elapsed, 0)
206 if self._download_status:
207 self._download_status.add_misc_event("AES", started, now())
208 self._consumer.write(plaintext)
210 class ImmutableFileNode:
211 implements(IImmutableFileNode)
213 # I wrap a CiphertextFileNode with a decryption key
214 def __init__(self, filecap, storage_broker, secret_holder, terminator,
216 assert isinstance(filecap, uri.CHKFileURI)
217 verifycap = filecap.get_verify_cap()
218 self._cnode = CiphertextFileNode(verifycap, storage_broker,
219 secret_holder, terminator, history)
220 assert isinstance(filecap, uri.CHKFileURI)
222 self._readkey = filecap.key
224 # TODO: I'm not sure about this.. what's the use case for node==node? If
225 # we keep it here, we should also put this on CiphertextFileNode
227 return self.u.__hash__()
228 def __eq__(self, other):
229 if isinstance(other, ImmutableFileNode):
230 return self.u.__eq__(other.u)
233 def __ne__(self, other):
234 if isinstance(other, ImmutableFileNode):
235 return self.u.__eq__(other.u)
239 def read(self, consumer, offset=0, size=None):
240 decryptor = DecryptingConsumer(consumer, self._readkey, offset)
241 d = self._cnode.read(decryptor, offset, size)
242 d.addCallback(lambda dc: consumer)
245 def raise_error(self):
248 def get_write_uri(self):
251 def get_readonly_uri(self):
252 return self.get_uri()
255 return self.u.to_string()
258 def get_readcap(self):
259 return self.u.get_readonly()
260 def get_verify_cap(self):
261 return self.u.get_verify_cap()
262 def get_repair_cap(self):
263 # CHK files can be repaired with just the verifycap
264 return self.u.get_verify_cap()
266 def get_storage_index(self):
267 return self.u.get_storage_index()
270 return self.u.get_size()
271 def get_current_size(self):
272 return defer.succeed(self.get_size())
274 def is_mutable(self):
277 def is_readonly(self):
280 def is_unknown(self):
283 def is_allowed_in_immutable_directory(self):
286 def check_and_repair(self, monitor, verify=False, add_lease=False):
287 return self._cnode.check_and_repair(monitor, verify, add_lease)
288 def check(self, monitor, verify=False, add_lease=False):
289 return self._cnode.check(monitor, verify, add_lease)
291 def get_best_readable_version(self):
293 Return an IReadable of the best version of this file. Since
294 immutable files can have only one version, we just return the
297 return defer.succeed(self)
300 def download_best_version(self):
302 Download the best version of this file, returning its contents
303 as a bytestring. Since there is only one version of an immutable
304 file, we download and return the contents of this file.
306 d = consumer.download_to_data(self)
309 # for an immutable file, download_to_data (specified in IReadable)
310 # is the same as download_best_version (specified in IFileNode). For
311 # mutable files, the difference is more meaningful, since they can
312 # have multiple versions.
313 download_to_data = download_best_version
316 # get_size() (IReadable), get_current_size() (IFilesystemNode), and
317 # get_size_of_best_version(IFileNode) are all the same for immutable
319 get_size_of_best_version = get_current_size