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 sm = prr.data['sharemap']
119 assert isinstance(sm, DictOfSets), sm
120 sm.update(ur.sharemap)
121 servers_responding = set(prr.data['servers-responding'])
122 servers_responding.union(ur.sharemap.iterkeys())
123 prr.data['servers-responding'] = list(servers_responding)
124 prr.data['count-shares-good'] = len(sm)
125 good_hosts = len(reduce(set.union, sm.itervalues(), set()))
126 prr.data['count-good-share-hosts'] = good_hosts
127 is_healthy = bool(len(sm) >= verifycap.total_shares)
128 is_recoverable = bool(len(sm) >= verifycap.needed_shares)
129 prr.set_healthy(is_healthy)
130 prr.set_recoverable(is_recoverable)
131 crr.repair_successful = is_healthy
132 prr.set_needs_rebalancing(len(sm) >= verifycap.total_shares)
134 crr.post_repair_results = prr
136 def _repair_error(f):
137 # as with mutable repair, I'm not sure if I want to pass
138 # through a failure or not. TODO
139 crr.repair_successful = False
140 crr.repair_failure = f
142 r = Repairer(self, storage_broker=sb, secret_holder=sh,
145 d.addCallbacks(_gather_repair_results, _repair_error)
148 d.addCallback(_maybe_repair)
151 def check(self, monitor, verify=False, add_lease=False):
152 verifycap = self._verifycap
153 sb = self._storage_broker
154 servers = sb.get_connected_servers()
155 sh = self._secret_holder
157 v = Checker(verifycap=verifycap, servers=servers,
158 verify=verify, add_lease=add_lease, secret_holder=sh,
162 class DecryptingConsumer:
163 """I sit between a CiphertextDownloader (which acts as a Producer) and
164 the real Consumer, decrypting everything that passes by. The real
165 Consumer sees the real Producer, but the Producer sees us instead of the
167 implements(IConsumer, IDownloadStatusHandlingConsumer)
169 def __init__(self, consumer, readkey, offset):
170 self._consumer = consumer
172 self._download_status = None
173 # TODO: pycryptopp CTR-mode needs random-access operations: I want
174 # either a=AES(readkey, offset) or better yet both of:
175 # a=AES(readkey, offset=0)
176 # a.process(ciphertext, offset=xyz)
177 # For now, we fake it with the existing iv= argument.
178 offset_big = offset // 16
179 offset_small = offset % 16
180 iv = binascii.unhexlify("%032x" % offset_big)
181 self._decryptor = AES(readkey, iv=iv)
182 self._decryptor.process("\x00"*offset_small)
184 def set_download_status_read_event(self, read_ev):
185 self._read_ev = read_ev
186 def set_download_status(self, ds):
187 self._download_status = ds
189 def registerProducer(self, producer, streaming):
190 # this passes through, so the real consumer can flow-control the real
191 # producer. Therefore we don't need to provide any IPushProducer
192 # methods. We implement all the IConsumer methods as pass-throughs,
193 # and only intercept write() to perform decryption.
194 self._consumer.registerProducer(producer, streaming)
195 def unregisterProducer(self):
196 self._consumer.unregisterProducer()
197 def write(self, ciphertext):
199 plaintext = self._decryptor.process(ciphertext)
201 elapsed = now() - started
202 self._read_ev.update(0, elapsed, 0)
203 if self._download_status:
204 self._download_status.add_misc_event("AES", started, now())
205 self._consumer.write(plaintext)
207 class ImmutableFileNode:
208 implements(IImmutableFileNode)
210 # I wrap a CiphertextFileNode with a decryption key
211 def __init__(self, filecap, storage_broker, secret_holder, terminator,
213 assert isinstance(filecap, uri.CHKFileURI)
214 verifycap = filecap.get_verify_cap()
215 self._cnode = CiphertextFileNode(verifycap, storage_broker,
216 secret_holder, terminator, history)
217 assert isinstance(filecap, uri.CHKFileURI)
219 self._readkey = filecap.key
221 # TODO: I'm not sure about this.. what's the use case for node==node? If
222 # we keep it here, we should also put this on CiphertextFileNode
224 return self.u.__hash__()
225 def __eq__(self, other):
226 if isinstance(other, ImmutableFileNode):
227 return self.u.__eq__(other.u)
230 def __ne__(self, other):
231 if isinstance(other, ImmutableFileNode):
232 return self.u.__eq__(other.u)
236 def read(self, consumer, offset=0, size=None):
237 decryptor = DecryptingConsumer(consumer, self._readkey, offset)
238 d = self._cnode.read(decryptor, offset, size)
239 d.addCallback(lambda dc: consumer)
242 def raise_error(self):
245 def get_write_uri(self):
248 def get_readonly_uri(self):
249 return self.get_uri()
252 return self.u.to_string()
255 def get_readcap(self):
256 return self.u.get_readonly()
257 def get_verify_cap(self):
258 return self.u.get_verify_cap()
259 def get_repair_cap(self):
260 # CHK files can be repaired with just the verifycap
261 return self.u.get_verify_cap()
263 def get_storage_index(self):
264 return self.u.get_storage_index()
267 return self.u.get_size()
268 def get_current_size(self):
269 return defer.succeed(self.get_size())
271 def is_mutable(self):
274 def is_readonly(self):
277 def is_unknown(self):
280 def is_allowed_in_immutable_directory(self):
283 def check_and_repair(self, monitor, verify=False, add_lease=False):
284 return self._cnode.check_and_repair(monitor, verify, add_lease)
285 def check(self, monitor, verify=False, add_lease=False):
286 return self._cnode.check(monitor, verify, add_lease)
288 def get_best_readable_version(self):
290 Return an IReadable of the best version of this file. Since
291 immutable files can have only one version, we just return the
294 return defer.succeed(self)
297 def download_best_version(self):
299 Download the best version of this file, returning its contents
300 as a bytestring. Since there is only one version of an immutable
301 file, we download and return the contents of this file.
303 d = consumer.download_to_data(self)
306 # for an immutable file, download_to_data (specified in IReadable)
307 # is the same as download_best_version (specified in IFileNode). For
308 # mutable files, the difference is more meaningful, since they can
309 # have multiple versions.
310 download_to_data = download_best_version
313 # get_size() (IReadable), get_current_size() (IFilesystemNode), and
314 # get_size_of_best_version(IFileNode) are all the same for immutable
316 get_size_of_best_version = get_current_size