#! /usr/bin/python -E
# Authors: Martin Kosek <mkosek@redhat.com>
#
# Copyright (C) 2011  Red Hat
# see file 'COPYING' for use and warranty information
#
# This program 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.
#
# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
#

from ipapython.config import IPAOptionParser
from ipapython import version
from ipapython import ipautil
from ipapython.ipautil import CalledProcessError
from ipaserver.install import installutils
import ipaclient.ipachangeconf
from optparse import OptionGroup
import logging
import sys
import os
import signal
import tempfile
import socket
import time
import threading
import errno

CONNECT_TIMEOUT = 5
RESPONDERS = [ ]
QUIET = False
CCACHE_FILE = "/etc/ipa/.conncheck_ccache"
KRB5_CONFIG = None

class CheckedPort(object):
    def __init__(self, port, stream, description):
        self.port = port
        self.stream = stream
        self.description = description

BASE_PORTS = [
                CheckedPort(389, True, "Directory Service: Unsecure port"),
                CheckedPort(636, True, "Directory Service: Secure port"),
                CheckedPort(88, True, "Kerberos KDC: TCP"),
                CheckedPort(88, False, "Kerberos KDC: UDP"),
                CheckedPort(464, True, "Kerberos Kpasswd: TCP"),
                CheckedPort(464, False, "Kerberos Kpasswd: UDP"),
                CheckedPort(80, True, "HTTP Server: Unsecure port"),
                CheckedPort(443, True, "HTTP Server: Secure port"),
             ]

CA_PORTS  = [
                CheckedPort(7389, True, "PKI-CA: Directory Service port"),
            ]

def print_info(msg):
    if not QUIET:
        print msg

def parse_options():
    parser = IPAOptionParser(version=version.VERSION)

    replica_group = OptionGroup(parser, "on-replica options")
    replica_group.add_option("-m", "--master", dest="master",
                      help="Master address with running IPA for output connection check")
    replica_group.add_option("-a", "--auto-master-check", dest="auto_master_check",
                      action="store_true",
                      default=False,
                      help="Automatically execute connection check on master")
    replica_group.add_option("-r", "--realm", dest="realm",
                      help="Realm name")
    replica_group.add_option("-k", "--kdc", dest="kdc",
                      help="Master KDC. Defaults to master address")
    replica_group.add_option("-p", "--principal", dest="principal",
                      default="admin", help="Principal to use to log in to remote master")
    replica_group.add_option("-w", "--password", dest="password", sensitive=True,
                      help="Password for the principal"),
    parser.add_option_group(replica_group)


    master_group = OptionGroup(parser, "on-master options")
    master_group.add_option("-R", "--replica", dest="replica",
                      help="Address of remote replica machine to check against")
    parser.add_option_group(master_group)

    common_group = OptionGroup(parser, "common options")
    common_group.add_option("-c", "--check-ca", dest="check_ca",
                      action="store_true",
                      default=False,
                      help="Check also ports for Certificate Authority")

    common_group.add_option("", "--hostname", dest="hostname",
                      help="The hostname of this server (FQDN). "
                           "By default a nodename from uname(2) is used.")
    parser.add_option_group(common_group)

    parser.add_option("-d", "--debug", dest="debug",
                      action="store_true",
                      default=False, help="Print debugging information")
    parser.add_option("-q", "--quiet", dest="quiet",
                      action="store_true",
                      default=False, help="Output only errors")

    options, args = parser.parse_args()
    safe_options = parser.get_safe_opts(options)

    if options.master and options.replica:
        parser.error("on-master and on-replica options are mutually exclusive!")

    if options.master:
        if options.auto_master_check and not options.realm:
            parser.error("Realm is parameter is required to connect to remote master!")
        if not os.getegid() == 0:
            parser.error("You can only run on-replica part as root.")

    if options.master and not options.kdc:
       options.kdc = options.master

    if not options.master and not options.replica:
       parser.error("No action: you should select either --replica or --master option.")

    if not options.hostname:
        options.hostname = socket.getfqdn()

    if options.quiet:
        global QUIET
        QUIET = True

    return safe_options, options

def logging_setup(options):
    if os.getegid() == 0:
        log_file = "/var/log/ipareplica-conncheck.log"
        old_umask = os.umask(077)
        logging.basicConfig(level=logging.DEBUG,
                        format='%(asctime)s %(levelname)s %(message)s',
                        filename=log_file,
                        filemode='w')
        os.umask(old_umask)

    console = logging.StreamHandler()
    # If the debug option is set, also log debug messages to the console
    if options.debug:
        console.setLevel(logging.DEBUG)
    else:
        # Otherwise, log critical and error messages
        console.setLevel(logging.ERROR)
    formatter = logging.Formatter('%(name)-12s: %(levelname)-8s %(message)s')
    console.setFormatter(formatter)
    logging.getLogger('').addHandler(console)

def clean_responders(responders):
    if not responders:
        return

    for responder in responders:
        responder.stop()

    for responder in responders:
        responder.join()
        responders.remove(responder)

def sigterm_handler(signum, frame):
    print_info("\nCleaning up...")

    global RESPONDERS
    clean_responders(RESPONDERS)

    sys.exit(1)

def configure_krb5_conf(realm, kdc, filename):

    krbconf = ipaclient.ipachangeconf.IPAChangeConf("IPA Installer")
    krbconf.setOptionAssignment(" = ")
    krbconf.setSectionNameDelimiters(("[","]"))
    krbconf.setSubSectionDelimiters(("{","}"))
    krbconf.setIndent(("","  ","    "))

    opts = [{'name':'comment', 'type':'comment', 'value':'File created by ipa-replica-conncheck'},
            {'name':'empty', 'type':'empty'}]

    #[libdefaults]
    libdefaults = [{'name':'default_realm', 'type':'option', 'value':realm}]
    libdefaults.append({'name':'dns_lookup_realm', 'type':'option', 'value':'false'})
    libdefaults.append({'name':'dns_lookup_kdc', 'type':'option', 'value':'false'})
    libdefaults.append({'name':'rdns', 'type':'option', 'value':'false'})
    libdefaults.append({'name':'ticket_lifetime', 'type':'option', 'value':'24h'})
    libdefaults.append({'name':'forwardable', 'type':'option', 'value':'yes'})

    opts.append({'name':'libdefaults', 'type':'section', 'value': libdefaults})
    opts.append({'name':'empty', 'type':'empty'})

    #the following are necessary only if DNS discovery does not work
    #[realms]
    realms_info =[{'name':'kdc', 'type':'option', 'value':ipautil.format_netloc(kdc, 88)},
                 {'name':'admin_server', 'type':'option', 'value':ipautil.format_netloc(kdc, 749)}]
    realms = [{'name':realm, 'type':'subsection', 'value':realms_info}]

    opts.append({'name':'realms', 'type':'section', 'value':realms})
    opts.append({'name':'empty', 'type':'empty'})

    #[appdefaults]
    pamopts = [{'name':'debug', 'type':'option', 'value':'false'},
               {'name':'ticket_lifetime', 'type':'option', 'value':'36000'},
               {'name':'renew_lifetime', 'type':'option', 'value':'36000'},
               {'name':'forwardable', 'type':'option', 'value':'true'},
               {'name':'krb4_convert', 'type':'option', 'value':'false'}]
    appopts = [{'name':'pam', 'type':'subsection', 'value':pamopts}]
    opts.append({'name':'appdefaults', 'type':'section', 'value':appopts})

    logging.debug("Writing temporary Kerberos configuration to %s:\n%s"
            % (filename, krbconf.dump(opts)))

    krbconf.newConf(filename, opts)

class PortResponder(threading.Thread):

    def __init__(self, port, socket_stream = True, socket_timeout=1):
        super(PortResponder, self).__init__()
        self.port = port
        self.socket_stream = socket_stream
        self.socket_timeout = socket_timeout
        self._stop_request = False

    def run(self):
        while not self._stop_request:
            try:
                ipautil.bind_port_responder(self.port, self.socket_stream,
                        self.socket_timeout, responder_data="FreeIPA")
            except socket.timeout:
                pass
            except socket.error, e:
                if e.errno == errno.EADDRINUSE:
                    time.sleep(1)
                else:
                    raise

    def stop(self):
        self._stop_request = True

def port_check(host, port_list):
    failed_ports = []
    for port in port_list:
        if ipautil.host_port_open(host, port.port, port.stream, CONNECT_TIMEOUT):
            result = "OK"
        else:
            failed_ports.append(port)
            result = "FAILED"
        print_info("   %s (%d): %s" % (port.description, port.port, result))

    if failed_ports:
        msg_ports = ", ".join([str(port.port) for port in failed_ports])
        raise RuntimeError("Port check failed! Inaccessible port(s): %s" % msg_ports)

def main():
    safe_options, options = parse_options()

    logging_setup(options)
    logging.debug('%s was invoked with options: %s' % (sys.argv[0], safe_options))
    logging.debug("missing options might be asked for interactively later\n")

    signal.signal(signal.SIGTERM, sigterm_handler)
    signal.signal(signal.SIGINT, sigterm_handler)

    required_ports = BASE_PORTS
    if options.check_ca:
        required_ports.extend(CA_PORTS)

    if options.replica:
        print_info("Check connection from master to remote replica '%s':" % options.replica)
        port_check(options.replica, required_ports)
        print_info("\nConnection from master to replica is OK.")

    # kinit to foreign master
    if options.master:
        # check ports on master first
        print_info("Check connection from replica to remote master '%s':" % options.master)
        port_check( options.master, required_ports)
        print_info("\nConnection from replica to master is OK.")

        # create listeners
        global RESPONDERS
        print_info("Start listening on required ports for remote master check")
        for port in required_ports:
            logging.debug("Start listening on port %d (%s)" % (port.port, port.description))
            responder = PortResponder(port.port, port.stream)
            responder.start()
            RESPONDERS.append(responder)

        if options.auto_master_check:
            (krb_fd, krb_name) = tempfile.mkstemp()
            os.close(krb_fd)
            configure_krb5_conf(options.realm, options.kdc, krb_name)
            global KRB5_CONFIG
            KRB5_CONFIG = krb_name

            print_info("Get credentials to log in to remote master")
            if options.principal.find('@') == -1:
                principal = '%s@%s' % (options.principal, options.realm)
                user = options.principal
            else:
                principal = options.principal
                user = options.principal.partition('@')[0]

            if options.password:
                password=options.password
            else:
                password = installutils.read_password(principal, confirm=False,
                           validate=False, retry=False)
                if password is None:
                    sys.exit("\nPrincipal password required")


            stderr=''
            (stdout, stderr, returncode) = ipautil.run(['/usr/bin/kinit', principal],
                 env={'KRB5_CONFIG':KRB5_CONFIG, 'KRB5CCNAME':CCACHE_FILE},
                 stdin=password, raiseonerr=False)
            if returncode != 0:
                raise RuntimeError("Cannot acquire Kerberos ticket: %s" % stderr)

            remote_check_opts = ['--replica %s' % options.hostname]
            if options.check_ca:
                remote_check_opts.append('--check-ca')

            print_info("Execute check on remote master")

            stderr = ''
            remote_addr = "%s@%s" % (user, options.master)
            (stdout, stderr, returncode) = ipautil.run(['/usr/bin/ssh',
                '-q', '-o StrictHostKeychecking=no',
                '-o UserKnownHostsFile=/dev/null', remote_addr,
                "/usr/sbin/ipa-replica-conncheck " + " ".join(remote_check_opts)],
                env={'KRB5_CONFIG':KRB5_CONFIG, 'KRB5CCNAME' : CCACHE_FILE},
                raiseonerr=False)

            print_info(stdout)

            if returncode != 0:
                raise RuntimeError("Remote master check failed with following error message(s):\n%s" % stderr)
        else:
            # wait until user  test is ready
            print_info("Listeners are started. Use CTRL+C to terminate the listening part after the test.")
            print_info("")
            print_info("Please run the following command on remote master:")

            remote_check_opts = ['--replica %s' % options.hostname]
            if options.check_ca:
                remote_check_opts.append('--check-ca')
            print_info("/usr/sbin/ipa-replica-conncheck " + " ".join(remote_check_opts))
            time.sleep(3600)
            print_info("Connection check timeout: terminating listening program")

if __name__ == "__main__":
    try:
        sys.exit(main())
    except SystemExit, e:
        sys.exit(e)
    except KeyboardInterrupt:
        sys.exit(1)
    except RuntimeError, e:
        sys.exit(e)
    finally:
        clean_responders(RESPONDERS)
        for file_name in (CCACHE_FILE, KRB5_CONFIG):
            if file_name:
                try:
                    os.remove(file_name)
                except OSError:
                    pass

