mirror of
https://github.com/ansible-collections/community.general.git
synced 2024-09-14 20:13:21 +02:00
6fe9a5e40c
* sends the serialized play_context into an already established connection * hooks the alarm_handler() method in the connection plugin if it exists * added configuration options for connect interval and retries * adds syslog logging to Server() instance This update will send the updated play_context back into an already established connection in case privilege escalation / descalation activities need to be performed. This change will also hook the alarm_handler() method in the connection instance (if available) and call it in case of a sigalarm raised. This update adds two new configuration options * PERSISTENT_CONNECT_INTERVAL - time to wait in between connection attempts * PERSISTENT_CONNECT_RETRIES - max number of retries
341 lines
12 KiB
Python
Executable file
341 lines
12 KiB
Python
Executable file
#!/usr/bin/env python
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# (c) 2016, Ansible, Inc. <support@ansible.com>
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#
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# This file is part of Ansible
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#
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# Ansible is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# Ansible is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with Ansible. If not, see <http://www.gnu.org/licenses/>.
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########################################################
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from __future__ import (absolute_import, division, print_function)
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__metaclass__ = type
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__requires__ = ['ansible']
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try:
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import pkg_resources
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except Exception:
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pass
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import fcntl
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import hashlib
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import os
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import shlex
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import signal
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import socket
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import struct
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import sys
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import time
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import traceback
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import syslog
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import datetime
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from io import BytesIO
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from ansible import constants as C
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from ansible.module_utils._text import to_bytes, to_native
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from ansible.module_utils.six.moves import cPickle, StringIO
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from ansible.playbook.play_context import PlayContext
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from ansible.plugins import connection_loader
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from ansible.utils.path import unfrackpath, makedirs_safe
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def do_fork():
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'''
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Does the required double fork for a daemon process. Based on
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http://code.activestate.com/recipes/66012-fork-a-daemon-process-on-unix/
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'''
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try:
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pid = os.fork()
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if pid > 0:
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return pid
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os.chdir("/")
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os.setsid()
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os.umask(0)
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try:
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pid = os.fork()
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if pid > 0:
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sys.exit(0)
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os.close(sys.stdin.fileno())
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os.close(sys.stdout.fileno())
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os.close(sys.stderr.fileno())
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return pid
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except OSError as e:
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sys.exit(1)
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except OSError as e:
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sys.exit(1)
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def send_data(s, data):
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packed_len = struct.pack('!Q',len(data))
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return s.sendall(packed_len + data)
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def recv_data(s):
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header_len = 8 # size of a packed unsigned long long
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data = b""
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while len(data) < header_len:
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d = s.recv(header_len - len(data))
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if not d:
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return None
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data += d
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data_len = struct.unpack('!Q',data[:header_len])[0]
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data = data[header_len:]
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while len(data) < data_len:
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d = s.recv(data_len - len(data))
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if not d:
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return None
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data += d
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return data
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class Server():
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def __init__(self, path, play_context):
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self.path = path
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self.play_context = play_context
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self._start_time = datetime.datetime.now()
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try:
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# FIXME: the connection loader here is created brand new,
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# so it will not see any custom paths loaded (ie. via
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# roles), so we will need to serialize the connection
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# loader and send it over as we do the PlayContext
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# in the main() method below.
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self.log('loading connection plugin %s' % str(play_context.connection))
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self.conn = connection_loader.get(play_context.connection, play_context, sys.stdin)
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self.conn._connect()
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self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
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self.socket.bind(path)
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self.socket.listen(1)
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except Exception as exc:
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self.log(exc)
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return
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signal.signal(signal.SIGALRM, self.alarm_handler)
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def log(self, msg):
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syslog_msg = '[%s] %s' % (self.play_context.remote_addr, msg)
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facility = getattr(syslog, C.DEFAULT_SYSLOG_FACILITY, syslog.LOG_USER)
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syslog.openlog('ansible-connection', 0, facility)
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syslog.syslog(syslog.LOG_INFO, syslog_msg)
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def dispatch(self, obj, name, *args, **kwargs):
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meth = getattr(obj, name, None)
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if meth:
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return meth(*args, **kwargs)
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def alarm_handler(self, signum, frame):
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'''
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Alarm handler
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'''
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# FIXME: this should also set internal flags for other
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# areas of code to check, so they can terminate
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# earlier than the socket going back to the accept
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# call and failing there.
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#
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# hooks the connection plugin to handle any cleanup
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self.dispatch(self.conn, 'alarm_handler', signum, frame)
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self.socket.close()
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def run(self):
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try:
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while True:
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# set the alarm, if we don't get an accept before it
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# goes off we exit (via an exception caused by the socket
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# getting closed while waiting on accept())
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# FIXME: is this the best way to exit? as noted above in the
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# handler we should probably be setting a flag to check
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# here and in other parts of the code
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signal.alarm(C.PERSISTENT_CONNECT_TIMEOUT)
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try:
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(s, addr) = self.socket.accept()
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# clear the alarm
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# FIXME: potential race condition here between the accept and
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# time to this call.
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signal.alarm(0)
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except:
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break
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while True:
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data = recv_data(s)
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if not data:
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break
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signal.alarm(C.DEFAULT_TIMEOUT)
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rc = 255
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try:
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if data.startswith(b'EXEC: '):
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cmd = data.split(b'EXEC: ')[1]
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(rc, stdout, stderr) = self.conn.exec_command(cmd)
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elif data.startswith(b'PUT: ') or data.startswith(b'FETCH: '):
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(op, src, dst) = shlex.split(to_native(data))
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stdout = stderr = ''
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try:
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if op == 'FETCH:':
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self.conn.fetch_file(src, dst)
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elif op == 'PUT:':
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self.conn.put_file(src, dst)
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rc = 0
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except:
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pass
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elif data.startswith(b'CONTEXT: '):
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pc_data = data.split(b'CONTEXT: ')[1]
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src = StringIO(pc_data)
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pc_data = cPickle.load(src)
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src.close()
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pc = PlayContext()
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pc.deserialize(pc_data)
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self.dispatch(self.conn, 'update_play_context', pc)
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continue
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else:
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stdout = ''
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stderr = 'Invalid action specified'
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except:
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stdout = ''
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stderr = traceback.format_exc()
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signal.alarm(0)
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send_data(s, to_bytes(str(rc)))
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send_data(s, to_bytes(stdout))
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send_data(s, to_bytes(stderr))
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s.close()
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except Exception as e:
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# FIXME: proper logging and error handling here
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self.log('runtime exception: %s' % e)
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print(traceback.format_exc())
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finally:
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# when done, close the connection properly and cleanup
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# the socket file so it can be recreated
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end_time = datetime.datetime.now()
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delta = end_time - self._start_time
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self.log('shutting down connection, connection was active for %s secs' % delta)
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try:
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self.conn.close()
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self.socket.close()
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except Exception as e:
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pass
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os.remove(self.path)
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def main():
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try:
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# read the play context data via stdin, which means depickling it
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# FIXME: as noted above, we will probably need to deserialize the
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# connection loader here as well at some point, otherwise this
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# won't find role- or playbook-based connection plugins
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cur_line = sys.stdin.readline()
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init_data = ''
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while cur_line.strip() != '#END_INIT#':
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if cur_line == '':
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raise Exception("EOL found before init data was complete")
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init_data += cur_line
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cur_line = sys.stdin.readline()
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src = BytesIO(to_bytes(init_data))
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pc_data = cPickle.load(src)
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#src.close()
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pc = PlayContext()
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pc.deserialize(pc_data)
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except Exception as e:
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# FIXME: better error message/handling/logging
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print("FAIL: %s" % e)
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print(traceback.format_exc())
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sys.exit(1)
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# here we create a hash to use later when creating the socket file,
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# so we can hide the info about the target host/user/etc.
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m = hashlib.sha256()
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for attr in ('connection', 'remote_addr', 'port', 'remote_user'):
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val = getattr(pc, attr, None)
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if val:
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m.update(to_bytes(val))
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# create the persistent connection dir if need be and create the paths
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# which we will be using later
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tmp_path = unfrackpath("$HOME/.ansible/pc")
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makedirs_safe(tmp_path)
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lk_path = unfrackpath("%s/.ansible_pc_lock" % tmp_path)
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sf_path = unfrackpath("%s/conn-%s" % (tmp_path, m.hexdigest()[0:12]))
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# if the socket file doesn't exist, spin up the daemon process
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lock_fd = os.open(lk_path, os.O_RDWR|os.O_CREAT, 0o600)
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fcntl.lockf(lock_fd, fcntl.LOCK_EX)
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if not os.path.exists(sf_path):
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pid = do_fork()
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if pid == 0:
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server = Server(sf_path, pc)
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fcntl.lockf(lock_fd, fcntl.LOCK_UN)
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os.close(lock_fd)
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server.run()
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sys.exit(0)
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fcntl.lockf(lock_fd, fcntl.LOCK_UN)
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os.close(lock_fd)
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# now connect to the daemon process
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# FIXME: if the socket file existed but the daemonized process was killed,
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# the connection will timeout here. Need to make this more resilient.
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rc = 0
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while rc == 0:
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data = sys.stdin.readline()
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if data == '':
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break
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if data.strip() == '':
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continue
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sf = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
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attempts = 1
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while True:
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try:
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sf.connect(sf_path)
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break
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except socket.error:
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# FIXME: better error handling/logging/message here
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time.sleep(C.PERSISTENT_CONNECT_INTERVAL)
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attempts += 1
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if attempts > C.PERSISTENT_CONNECT_RETRIES:
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sys.stderr.write("failed to connect to the host, connection timeout")
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sys.exit(255)
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#
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# send the play_context back into the connection so the connection
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# can handle any privilege escalation or deescalation activities
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#
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pc_data = 'CONTEXT: %s' % src.getvalue()
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send_data(sf, to_bytes(pc_data))
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src.close()
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send_data(sf, to_bytes(data.strip()))
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rc = int(recv_data(sf), 10)
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stdout = recv_data(sf)
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stderr = recv_data(sf)
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sys.stdout.write(to_native(stdout))
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sys.stderr.write(to_native(stderr))
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sf.close()
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break
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sys.exit(rc)
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if __name__ == '__main__':
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main()
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