ansible/bin/ansible-connection
Ganesh Nalawade bb998a3cd2 Add fix to read correct socket path recieved from ansible-connection (#27560)
Currently socket path is send from `ansible-connection` (running as background
process) over stdout. This can conflict with debug logs that are also send on
stdout resulting in incorrect socket path received by the main process.

To avoid this add a socket path delimiter string which is recevied by
main process and socket path is retrieved based on delimiter string.

This implementation will change in future when ansible-connection
framework is made more robust.
2017-08-01 19:32:25 +05:30

386 lines
13 KiB
Python
Executable file

#!/usr/bin/env python
# (c) 2017, Ansible, Inc. <support@ansible.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible. If not, see <http://www.gnu.org/licenses/>.
########################################################
from __future__ import (absolute_import, division, print_function)
__metaclass__ = type
__requires__ = ['ansible']
try:
import pkg_resources
except Exception:
pass
import fcntl
import os
import shlex
import signal
import socket
import sys
import time
import traceback
import datetime
import errno
from ansible import constants as C
from ansible.module_utils._text import to_bytes, to_native, to_text
from ansible.module_utils.six import PY3
from ansible.module_utils.six.moves import cPickle
from ansible.module_utils.connection import send_data, recv_data
from ansible.playbook.play_context import PlayContext
from ansible.plugins import connection_loader
from ansible.utils.path import unfrackpath, makedirs_safe
from ansible.errors import AnsibleConnectionFailure
from ansible.utils.display import Display
def do_fork():
'''
Does the required double fork for a daemon process. Based on
http://code.activestate.com/recipes/66012-fork-a-daemon-process-on-unix/
'''
try:
pid = os.fork()
if pid > 0:
return pid
# This is done as a 'good practice' for daemons, but we need to keep the cwd
# leaving it here as a note that we KNOW its good practice but are not doing it on purpose.
#os.chdir("/")
os.setsid()
os.umask(0)
try:
pid = os.fork()
if pid > 0:
sys.exit(0)
if C.DEFAULT_LOG_PATH != '':
out_file = open(C.DEFAULT_LOG_PATH, 'ab+')
err_file = open(C.DEFAULT_LOG_PATH, 'ab+', 0)
else:
out_file = open('/dev/null', 'ab+')
err_file = open('/dev/null', 'ab+', 0)
os.dup2(out_file.fileno(), sys.stdout.fileno())
os.dup2(err_file.fileno(), sys.stderr.fileno())
os.close(sys.stdin.fileno())
return pid
except OSError as e:
sys.exit(1)
except OSError as e:
sys.exit(1)
class Server():
def __init__(self, socket_path, play_context):
self.socket_path = socket_path
self.play_context = play_context
display.display(
'creating new control socket for host %s:%s as user %s' %
(play_context.remote_addr, play_context.port, play_context.remote_user),
log_only=True
)
display.display('control socket path is %s' % socket_path, log_only=True)
display.display('current working directory is %s' % os.getcwd(), log_only=True)
self._start_time = datetime.datetime.now()
display.display("using connection plugin %s" % self.play_context.connection, log_only=True)
self.connection = connection_loader.get(play_context.connection, play_context, sys.stdin)
self.connection._connect()
if not self.connection.connected:
raise AnsibleConnectionFailure('unable to connect to remote host %s' % self._play_context.remote_addr)
connection_time = datetime.datetime.now() - self._start_time
display.display('connection established to %s in %s' % (play_context.remote_addr, connection_time), log_only=True)
self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
self.socket.bind(self.socket_path)
self.socket.listen(1)
display.display('local socket is set to listening', log_only=True)
def run(self):
try:
while True:
signal.signal(signal.SIGALRM, self.connect_timeout)
signal.signal(signal.SIGTERM, self.handler)
signal.alarm(C.PERSISTENT_CONNECT_TIMEOUT)
(s, addr) = self.socket.accept()
display.display('incoming request accepted on persistent socket', log_only=True)
signal.alarm(0)
while True:
data = recv_data(s)
if not data:
break
signal.signal(signal.SIGALRM, self.command_timeout)
signal.alarm(self.play_context.timeout)
op = to_text(data.split(b':')[0])
display.display('socket operation is %s' % op, log_only=True)
method = getattr(self, 'do_%s' % op, None)
rc = 255
stdout = stderr = ''
if not method:
stderr = 'Invalid action specified'
else:
rc, stdout, stderr = method(data)
signal.alarm(0)
display.display('socket operation completed with rc %s' % rc, log_only=True)
send_data(s, to_bytes(rc))
send_data(s, to_bytes(stdout))
send_data(s, to_bytes(stderr))
s.close()
except Exception as e:
# socket.accept() will raise EINTR if the socket.close() is called
if e.errno != errno.EINTR:
display.display(traceback.format_exc(), log_only=True)
finally:
# when done, close the connection properly and cleanup
# the socket file so it can be recreated
self.shutdown()
end_time = datetime.datetime.now()
delta = end_time - self._start_time
display.display('shutdown local socket, connection was active for %s secs' % delta, log_only=True)
def connect_timeout(self, signum, frame):
display.display('connect timeout triggered, timeout value is %s secs' % C.PERSISTENT_CONNECT_TIMEOUT, log_only=True)
self.shutdown()
def command_timeout(self, signum, frame):
display.display('commnad timeout triggered, timeout value is %s secs' % self.play_context.timeout, log_only=True)
self.shutdown()
def handler(self, signum, frame):
display.display('signal handler called with signal %s' % signum, log_only=True)
self.shutdown()
def shutdown(self):
display.display('shutdown persistent connection requested', log_only=True)
if not os.path.exists(self.socket_path):
display.display('persistent connection is not active', log_only=True)
return
try:
if self.socket:
display.display('closing local listener', log_only=True)
self.socket.close()
if self.connection:
display.display('closing the connection', log_only=True)
self.connection.close()
except:
pass
finally:
if os.path.exists(self.socket_path):
display.display('removing the local control socket', log_only=True)
os.remove(self.socket_path)
display.display('shutdown complete', log_only=True)
def do_EXEC(self, data):
cmd = data.split(b'EXEC: ')[1]
return self.connection.exec_command(cmd)
def do_PUT(self, data):
(op, src, dst) = shlex.split(to_native(data))
return self.connection.fetch_file(src, dst)
def do_FETCH(self, data):
(op, src, dst) = shlex.split(to_native(data))
return self.connection.put_file(src, dst)
def do_CONTEXT(self, data):
pc_data = data.split(b'CONTEXT: ', 1)[1]
if PY3:
pc_data = cPickle.loads(pc_data, encoding='bytes')
else:
pc_data = cPickle.loads(pc_data)
pc = PlayContext()
pc.deserialize(pc_data)
try:
self.connection.update_play_context(pc)
except AttributeError:
pass
return (0, 'ok', '')
def do_RUN(self, data):
timeout = self.play_context.timeout
while bool(timeout):
if os.path.exists(self.socket_path):
break
time.sleep(1)
timeout -= 1
return 0, b'\n#SOCKET_PATH#: %s\n' % self.socket_path, ''
def communicate(sock, data):
send_data(sock, data)
rc = int(recv_data(sock), 10)
stdout = recv_data(sock)
stderr = recv_data(sock)
return (rc, stdout, stderr)
def main():
# Need stdin as a byte stream
if PY3:
stdin = sys.stdin.buffer
else:
stdin = sys.stdin
try:
# read the play context data via stdin, which means depickling it
# FIXME: as noted above, we will probably need to deserialize the
# connection loader here as well at some point, otherwise this
# won't find role- or playbook-based connection plugins
cur_line = stdin.readline()
init_data = b''
while cur_line.strip() != b'#END_INIT#':
if cur_line == b'':
raise Exception("EOF found before init data was complete")
init_data += cur_line
cur_line = stdin.readline()
if PY3:
pc_data = cPickle.loads(init_data, encoding='bytes')
else:
pc_data = cPickle.loads(init_data)
pc = PlayContext()
pc.deserialize(pc_data)
except Exception as e:
# FIXME: better error message/handling/logging
sys.stderr.write(traceback.format_exc())
sys.exit("FAIL: %s" % e)
ssh = connection_loader.get('ssh', class_only=True)
cp = ssh._create_control_path(pc.remote_addr, pc.connection, pc.remote_user)
# create the persistent connection dir if need be and create the paths
# which we will be using later
tmp_path = unfrackpath(C.PERSISTENT_CONTROL_PATH_DIR)
makedirs_safe(tmp_path)
lock_path = unfrackpath("%s/.ansible_pc_lock" % tmp_path)
socket_path = unfrackpath(cp % dict(directory=tmp_path))
# if the socket file doesn't exist, spin up the daemon process
lock_fd = os.open(lock_path, os.O_RDWR|os.O_CREAT, 0o600)
fcntl.lockf(lock_fd, fcntl.LOCK_EX)
if not os.path.exists(socket_path):
pid = do_fork()
if pid == 0:
rc = 0
try:
server = Server(socket_path, pc)
except AnsibleConnectionFailure as exc:
display.display('connecting to host %s returned an error' % pc.remote_addr, log_only=True)
display.display(str(exc), log_only=True)
rc = 1
except Exception as exc:
display.display('failed to create control socket for host %s' % pc.remote_addr, log_only=True)
display.display(traceback.format_exc(), log_only=True)
rc = 1
fcntl.lockf(lock_fd, fcntl.LOCK_UN)
os.close(lock_fd)
if rc == 0:
server.run()
sys.exit(rc)
else:
display.display('re-using existing socket for %s@%s:%s' % (pc.remote_user, pc.remote_addr, pc.port), log_only=True)
fcntl.lockf(lock_fd, fcntl.LOCK_UN)
os.close(lock_fd)
timeout = pc.timeout
while bool(timeout):
if os.path.exists(socket_path):
display.vvvv('connected to local socket in %s' % (pc.timeout - timeout), pc.remote_addr)
break
time.sleep(1)
timeout -= 1
else:
raise AnsibleConnectionFailure('timeout waiting for local socket', pc.remote_addr)
# now connect to the daemon process
# FIXME: if the socket file existed but the daemonized process was killed,
# the connection will timeout here. Need to make this more resilient.
while True:
data = stdin.readline()
if data == b'':
break
if data.strip() == b'':
continue
sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
attempts = C.PERSISTENT_CONNECT_RETRIES
while bool(attempts):
try:
sock.connect(socket_path)
break
except socket.error:
time.sleep(C.PERSISTENT_CONNECT_INTERVAL)
attempts -= 1
else:
display.display('number of connection attempts exceeded, unable to connect to control socket', pc.remote_addr, pc.remote_user, log_only=True)
display.display('persistent_connect_interval=%s, persistent_connect_retries=%s' % (C.PERSISTENT_CONNECT_INTERVAL, C.PERSISTENT_CONNECT_RETRIES), pc.remote_addr, pc.remote_user, log_only=True)
sys.stderr.write('failed to connect to control socket')
sys.exit(255)
# send the play_context back into the connection so the connection
# can handle any privilege escalation activities
pc_data = b'CONTEXT: %s' % init_data
communicate(sock, pc_data)
rc, stdout, stderr = communicate(sock, data.strip())
sys.stdout.write(to_native(stdout))
sys.stderr.write(to_native(stderr))
sock.close()
break
sys.exit(rc)
if __name__ == '__main__':
display = Display()
main()