#!/usr/bin/env python
# pynslcd.py - main daemon module
#
# Copyright (C) 2010, 2011, 2012, 2013 Arthur de Jong
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301 USA
import daemon
import logging
import logging.handlers
import os
import signal
import sys
import syslog
import threading
import ldap
from tio import TIOStream
import cfg
import common
import constants
import mypidfile
import search
# the name of the program
program_name = 'pynslcd'
# flag to indicate whether we are in debugging mode
debugging = 0
# flag to indicate user requested the --check option
checkonly = False
class MyFormatter(logging.Formatter):
def format(self, record):
record.prefix = 'DEBUG: ' if record.levelno == logging.DEBUG else ''
return super(MyFormatter, self).format(record)
class MySysLogHandler(logging.Handler):
mapping = {
logging.DEBUG: syslog.LOG_DEBUG,
logging.INFO: syslog.LOG_INFO,
logging.WARNING: syslog.LOG_WARNING,
logging.ERROR: syslog.LOG_ERR,
logging.CRITICAL: syslog.LOG_CRIT,
}
def __init__(self):
super(MySysLogHandler, self).__init__()
syslog.openlog(program_name, syslog.LOG_PID, syslog.LOG_DAEMON)
def emit(self, record):
priority = self.mapping.get(record.levelno, syslog.LOG_WARNING)
msg = self.format(record)
for l in msg.splitlines():
syslog.syslog(priority, l)
# configure logging
stderrhandler = logging.StreamHandler(sys.stderr)
stderrhandler.setFormatter(MyFormatter('pynslcd: %(prefix)s%(message)s'))
logging.getLogger().addHandler(stderrhandler)
logging.getLogger().setLevel(logging.INFO)
def display_version(fp):
fp.write('%(PACKAGE_STRING)s\n'
'Written by Arthur de Jong.\n'
'\n'
'Copyright (C) 2010-2013 Arthur de Jong\n'
'This is free software; see the source for copying conditions. There is NO\n'
'warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n'
% {'PACKAGE_STRING': constants.PACKAGE_STRING, })
def display_usage(fp):
fp.write("Usage: %(program_name)s [OPTION]...\n"
"Name Service LDAP connection daemon.\n"
" -c, --check check if the daemon already is running\n"
" -d, --debug don't fork and print debugging to stderr\n"
" --help display this help and exit\n"
" --version output version information and exit\n"
"\n"
"Report bugs to <%(PACKAGE_BUGREPORT)s>.\n"
% {'program_name': program_name,
'PACKAGE_BUGREPORT': constants.PACKAGE_BUGREPORT, })
def parse_cmdline():
"""Parse command-line arguments."""
import getopt
global program_name
program_name = sys.argv[0] or program_name
try:
optlist, args = getopt.gnu_getopt(sys.argv[1:],
'cdhV', ('check', 'debug', 'help', 'version', ))
for flag, arg in optlist:
if flag in ('-c', '--check'):
global checkonly
checkonly = True
elif flag in ('-d', '--debug'):
global debugging
debugging += 1
elif flag in ('-h', '--help'):
display_usage(sys.stdout)
sys.exit(0)
elif flag in ('-V', '--version'):
display_version(sys.stdout)
sys.exit(0)
if len(args):
raise getopt.GetoptError('unrecognized option \'%s\'' % args[0], args[0])
except getopt.GetoptError, reason:
sys.stderr.write("%(program_name)s: %(reason)s\n"
"Try '%(program_name)s --help' for more information.\n"
% {'program_name': program_name,
'reason': reason, })
sys.exit(1)
def create_socket():
"""Returns a socket ready to answer requests from the client."""
import socket
import fcntl
sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
# remove existing named socket
try:
os.unlink(constants.NSLCD_SOCKET)
except OSError:
pass # ignore any problems
# bind to named socket
sock.bind(constants.NSLCD_SOCKET)
# close the file descriptor on exit
fcntl.fcntl(sock, fcntl.F_SETFD, fcntl.FD_CLOEXEC)
# set permissions of socket so anybody can do requests
os.chmod(constants.NSLCD_SOCKET, 0666)
# start listening for connections
sock.listen(socket.SOMAXCONN)
return sock
def log_newsession():
pass
# FIXME: implement
def getpeercred(fd):
"""Return uid, gid and pid of calling application."""
import struct
import socket
SO_PEERCRED = 17
creds = fd.getsockopt(socket.SOL_SOCKET, SO_PEERCRED, struct.calcsize('3i'))
pid, uid, gid = struct.unpack('3i', creds)
return uid, gid, pid
handlers = {}
handlers.update(common.get_handlers('alias'))
handlers.update(common.get_handlers('ether'))
handlers.update(common.get_handlers('group'))
handlers.update(common.get_handlers('host'))
handlers.update(common.get_handlers('netgroup'))
handlers.update(common.get_handlers('network'))
handlers.update(common.get_handlers('pam'))
handlers.update(common.get_handlers('passwd'))
handlers.update(common.get_handlers('protocol'))
handlers.update(common.get_handlers('rpc'))
handlers.update(common.get_handlers('service'))
handlers.update(common.get_handlers('shadow'))
def acceptconnection(session):
# accept a new connection
conn, addr = nslcd_serversocket.accept()
# See: http://docs.python.org/library/socket.html#socket.socket.settimeout
fp = None
try:
# probably use finally
# indicate new connection to logging module (genrates unique id)
log_newsession()
# log connection
try:
uid, gid, pid = getpeercred(conn)
logging.debug('connection from pid=%r uid=%r gid=%r', pid, uid, gid)
except:
raise # FIXME: handle exception gracefully
# create a stream object
fp = TIOStream(conn)
# read request
version = fp.read_int32()
if version != constants.NSLCD_VERSION:
logging.debug('wrong nslcd version id (%r)', version)
return
action = fp.read_int32()
try:
handler = handlers[action]
except KeyError:
logging.warning('invalid action id: 0x%08x', action)
return
handler(fp, session, uid)()
finally:
if fp:
fp.close()
def disable_nss_ldap():
"""Disable the nss_ldap module to avoid lookup loops."""
import ctypes
lib = ctypes.CDLL(constants.NSS_LDAP_SONAME)
try:
ctypes.c_int.in_dll(lib, '_nss_ldap_enablelookups').value = 0
except ValueError:
logging.warn('probably older NSS module loaded', exc_info=True)
try:
version_info = (ctypes.c_char_p * 2).in_dll(lib, '_nss_ldap_version')
logging.debug('NSS_LDAP %s %s', version_info[0], version_info[1])
except ValueError:
logging.warn('probably older NSS module loaded', exc_info=True)
def worker():
session = search.Connection()
while True:
try:
acceptconnection(session)
except:
logging.exception('exception in worker')
# ignore all exceptions, just keep going
if __name__ == '__main__':
# parse options
parse_cmdline()
# clean the environment
os.environ.clear()
os.putenv('HOME', '/')
os.putenv('TMPDIR', '/tmp')
os.putenv('LDAPNOINIT', '1')
# set log level
if debugging:
logging.getLogger().setLevel(logging.DEBUG)
# disable ldap lookups of host names to avoid lookup loop
disable_nss_ldap()
# TODO: implement
#if myldap_set_debuglevel(cfg.debug) != LDAP_SUCCESS:
# sys.exit(1)
# read configuration file
cfg.read(constants.NSLCD_CONF_PATH)
# set process title
try:
import setproctitle
setproctitle.setproctitle('pynslcd')
except ImportError:
pass
# set a default umask for the pidfile and socket
os.umask(0022)
# see if someone already locked the pidfile
pidfile = mypidfile.MyPIDLockFile(constants.NSLCD_PIDFILE)
# see if --check option was given
if checkonly:
if pidfile.is_locked():
logging.debug('pidfile (%s) is locked', constants.NSLCD_PIDFILE)
sys.exit(0)
else:
logging.debug('pidfile (%s) is not locked', constants.NSLCD_PIDFILE)
sys.exit(1)
# normal check for pidfile locked
if pidfile.is_locked():
logging.error('daemon may already be active, cannot acquire lock (%s)',
constants.NSLCD_PIDFILE)
sys.exit(1)
# daemonize
if debugging:
daemon = pidfile
else:
daemon = daemon.DaemonContext(
pidfile=pidfile,
signal_map={
signal.SIGTERM: 'terminate',
signal.SIGINT: 'terminate',
signal.SIGPIPE: None,
})
# start daemon
with daemon:
try:
# start normal logging as configured
if not debugging:
for method, level in cfg.logs:
if method == 'syslog':
handler = MySysLogHandler()
handler.setFormatter(MyFormatter('%(prefix)s%(message)s'))
else:
handler = logging.FileHandler(method, encoding='utf-8')
handler.setFormatter(MyFormatter('%(asctime)s %(prefix)s%(message)s'))
handler.setLevel(level)
logging.getLogger().addHandler(handler)
logging.getLogger().setLevel(min(level for method, level in cfg.logs))
logging.getLogger().removeHandler(stderrhandler)
logging.info('version %s starting', constants.VERSION)
# create socket
nslcd_serversocket = create_socket()
# load supplementary groups
if cfg.uid is not None:
import pwd
import grp
u = pwd.getpwnam(cfg.uid)
if cfg.gid is None:
gid = u.pw_gid
else:
gid = grp.getgrnam(cfg.gid).gr_gid
# set supplementary groups, gid and uid
os.initgroups(u.pw_name, gid)
os.setgid(gid)
os.setuid(u.pw_uid)
os.environ['HOME'] = u.pw_dir
logging.info('accepting connections')
# set global LDAP configuration
if cfg.tls_reqcert is not None:
ldap.set_option(ldap.OPT_X_TLS_REQUIRE_CERT, cfg.tls_reqcert)
if cfg.tls_cacertdir:
ldap.set_option(ldap.OPT_X_TLS_CACERTDIR, cfg.tls_cacertdir)
if cfg.tls_cacertfile:
ldap.set_option(ldap.OPT_X_TLS_CACERTFILE, cfg.tls_cacertfile)
if cfg.tls_randfile:
ldap.set_option(ldap.OPT_X_TLS_RANDOM_FILE, cfg.tls_randfile)
if cfg.tls_ciphers:
ldap.set_option(ldap.OPT_X_TLS_CIPHER_SUITE, cfg.tls_ciphers)
if cfg.tls_cert:
ldap.set_option(ldap.OPT_X_TLS_CERTFILE, cfg.tls_cert)
if cfg.tls_key:
ldap.set_option(ldap.OPT_X_TLS_KEYFILE, cfg.tls_key)
# start worker threads
threads = []
for i in range(cfg.threads):
thread = threading.Thread(target=worker, name='thread%d' % i)
thread.setDaemon(True)
thread.start()
logging.debug('started thread %s', thread.getName())
threads.append(thread)
# wait for all threads to die
for thread in threads:
thread.join(10000)
except:
logging.exception('main loop exit')
# no need to re-raise since we are exiting anyway