/usr/lib/python2.7/dist-packages/oslo_privsep/comm.py is in python-oslo.privsep 1.27.0-0ubuntu3.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 | # Copyright 2015 Rackspace Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""Serialization/Deserialization for privsep.
The wire format is a stream of msgpack objects encoding primitive
python datatypes. Msgpack 'raw' is assumed to be a valid utf8 string
(msgpack 2.0 'bin' type is used for bytes). Python lists are
converted to tuples during serialization/deserialization.
"""
import logging
import socket
import threading
import msgpack
import six
from oslo_privsep._i18n import _
LOG = logging.getLogger(__name__)
try:
import greenlet
def _get_thread_ident():
# This returns something sensible, even if the current thread
# isn't a greenthread
return id(greenlet.getcurrent())
except ImportError:
def _get_thread_ident():
return threading.current_thread().ident
class Serializer(object):
def __init__(self, writesock):
self.writesock = writesock
def send(self, msg):
buf = msgpack.packb(msg, use_bin_type=True)
self.writesock.sendall(buf)
def close(self):
# Hilarious. `socket._socketobject.close()` doesn't actually
# call `self._sock.close()`. Oh well, we really wanted a half
# close anyway.
self.writesock.shutdown(socket.SHUT_WR)
class Deserializer(six.Iterator):
def __init__(self, readsock):
self.readsock = readsock
self.unpacker = msgpack.Unpacker(use_list=False, encoding='utf-8')
def __iter__(self):
return self
def __next__(self):
while True:
try:
return next(self.unpacker)
except StopIteration:
try:
buf = self.readsock.recv(4096)
if not buf:
raise
self.unpacker.feed(buf)
except socket.timeout:
pass
class Future(object):
"""A very simple object to track the return of a function call"""
def __init__(self, lock):
self.condvar = threading.Condition(lock)
self.error = None
self.data = None
def set_result(self, data):
"""Must already be holding lock used in constructor"""
self.data = data
self.condvar.notify()
def set_exception(self, exc):
"""Must already be holding lock used in constructor"""
self.error = exc
self.condvar.notify()
def result(self):
"""Must already be holding lock used in constructor"""
self.condvar.wait()
if self.error is not None:
raise self.error
return self.data
class ClientChannel(object):
def __init__(self, sock):
self.writer = Serializer(sock)
self.lock = threading.Lock()
self.reader_thread = threading.Thread(
name='privsep_reader',
target=self._reader_main,
args=(Deserializer(sock),),
)
self.reader_thread.daemon = True
self.outstanding_msgs = {}
self.reader_thread.start()
def _reader_main(self, reader):
"""This thread owns and demuxes the read channel"""
for msg in reader:
msgid, data = msg
if msgid is None:
self.out_of_band(data)
else:
with self.lock:
if msgid not in self.outstanding_msgs:
raise AssertionError("msgid should in "
"outstanding_msgs.")
self.outstanding_msgs[msgid].set_result(data)
# EOF. Perhaps the privileged process exited?
# Send an IOError to any oustanding waiting readers. Assuming
# the write direction is also closed, any new writes should
# get an immediate similar error.
LOG.debug('EOF on privsep read channel')
exc = IOError(_('Premature eof waiting for privileged process'))
with self.lock:
for mbox in self.outstanding_msgs.values():
mbox.set_exception(exc)
def out_of_band(self, msg):
"""Received OOB message. Subclasses might want to override this."""
pass
def send_recv(self, msg):
myid = _get_thread_ident()
future = Future(self.lock)
with self.lock:
if myid in self.outstanding_msgs:
raise AssertionError("myid shoudn't be in outstanding_msgs.")
self.outstanding_msgs[myid] = future
try:
self.writer.send((myid, msg))
reply = future.result()
finally:
del self.outstanding_msgs[myid]
return reply
def close(self):
with self.lock:
self.writer.close()
self.reader_thread.join()
class ServerChannel(six.Iterator):
"""Server-side twin to ClientChannel"""
def __init__(self, sock):
self.rlock = threading.Lock()
self.reader_iter = iter(Deserializer(sock))
self.wlock = threading.Lock()
self.writer = Serializer(sock)
def __iter__(self):
return self
def __next__(self):
with self.rlock:
return next(self.reader_iter)
def send(self, msg):
with self.wlock:
self.writer.send(msg)
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