#!/usr/bin/python -E
#
# Authors:
#   Rob Crittenden <rcritten@redhat.com>
#
# Copyright (C) 2012  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/>.
#
# Configure the automount client for ldap.

import sys
import os
import urlparse
import time
import tempfile

import SSSDConfig

from optparse import OptionParser
from ipalib import api, errors
from ipapython import sysrestore
from ipapython import ipautil
from ipaclient import ipadiscovery
from ipaclient import ipachangeconf
from ipapython.ipa_log_manager import *
from ipapython.dn import DN
from ipapython import services as ipaservices

AUTOFS_CONF = '/etc/sysconfig/autofs'
NSSWITCH_CONF = '/etc/nsswitch.conf'
AUTOFS_LDAP_AUTH = '/etc/autofs_ldap_auth.conf'
NFS_CONF = '/etc/sysconfig/nfs'
IDMAPD_CONF = '/etc/idmapd.conf'

def parse_options():
    usage = "%prog [options]\n"
    parser = OptionParser(usage=usage)
    parser.add_option("--server", dest="server", help="IPA server")
    parser.add_option("--location", dest="location", help="Automount location",
        default="default")
    parser.add_option("-S", "--no-sssd", dest="sssd",
                      action="store_false", default=True,
                      help="Do not configure the client to use SSSD for automount")
    parser.add_option("--debug", dest="debug", action="store_true",
        default=False, help="enable debugging")
    parser.add_option("-U", "--unattended", dest="unattended",
        action="store_true", default=False,
        help="unattended installation never prompts the user")
    parser.add_option("--uninstall", dest="uninstall", action="store_true",
        default=False, help="Unconfigure automount")

    options, args = parser.parse_args()
    return options, args

def wait_for_sssd():
    """
    It takes a bit for sssd to get going, lets loop until it is
    serving data.

    This function returns nothing.
    """
    n = 0
    found = False
    time.sleep(1)
    while n < 10 and not found:
        try:
            ipautil.run(["getent", "passwd", "admin@%s" % api.env.realm])
            found = True
        except Exception, e:
            time.sleep(1)
            n = n + 1

    # This should never happen but if it does, may as well warn the user
    if not found:
        err_msg = ("Unable to find 'admin' user with "
                   "'getent passwd admin@%s'!" % api.env.realm)
        root_logger.debug(err_msg)
        print err_msg
        print "This may mean that sssd didn't re-start properly after the configuration changes."

def configure_xml(fstore):
    from lxml import etree

    fstore.backup_file(AUTOFS_LDAP_AUTH)

    try:
        f = open(AUTOFS_LDAP_AUTH, 'r')
        lines = f.read()
        f.close()

        saslconf = etree.fromstring(lines)
        element = saslconf.xpath('//autofs_ldap_sasl_conf')
        root = saslconf.getroottree()
    except IOError, e:
        root_logger.debug('Unable to open file %s' % e)
        root_logger.debug('Creating new from template')
        element = [etree.Element('autofs_ldap_sasl_conf')]
        root = element[0].getroottree()

    if len(element) != 1:
        raise RuntimeError('Unable to parse %s' % AUTOFS_LDAP_AUTH)

    element[0].set('usetls', 'no')
    element[0].set('tlsrequired', 'no')
    element[0].set('authrequired', 'yes')
    element[0].set('authtype', 'GSSAPI')
    element[0].set('clientprinc', 'host/%s@%s' % (api.env.host, api.env.realm))

    newconf = open(AUTOFS_LDAP_AUTH, 'w')
    try:
        root.write(newconf, pretty_print=True, xml_declaration=True, encoding='UTF-8')
        newconf.close()
    except IOError, e:
        print "Unable to write %s: %s" % (AUTOFS_LDAP_AUTH, e)
    print "Configured %s" % AUTOFS_LDAP_AUTH

def configure_nsswitch(fstore, options):
    """
    Point automount to ldap in nsswitch.conf
    """
    fstore.backup_file(NSSWITCH_CONF)

    conf = ipachangeconf.IPAChangeConf("IPA Installer")
    conf.setOptionAssignment(':')

    if options.sssd:
        nss_value = ' sss files'
    else:
        nss_value = ' ldap files'

    opts = [{'name':'automount', 'type':'option', 'action':'set', 'value':nss_value},
            {'name':'empty', 'type':'empty'}]

    conf.changeConf(NSSWITCH_CONF, opts)

    print "Configured %s" % NSSWITCH_CONF

def configure_autofs_sssd(fstore, statestore, autodiscover, options):
    try:
        sssdconfig = SSSDConfig.SSSDConfig()
        sssdconfig.import_config()
        domains = sssdconfig.list_active_domains()
    except Exception, e:
        sys.exit(e)

    try:
        sssdconfig.new_service('autofs')
    except SSSDConfig.ServiceAlreadyExists:
        pass
    except SSSDConfig.ServiceNotRecognizedError:
        root_logger.error("Unable to activate the Autofs service in SSSD config.")
        root_logger.info(
            "Please make sure you have SSSD built with autofs support installed.")
        root_logger.info(
            "Configure autofs support manually in /etc/sssd/sssd.conf.")
        sys.exit("Cannot create the autofs service in sssd.conf")

    sssdconfig.activate_service('autofs')

    domain = None
    for name in domains:
        domain = sssdconfig.get_domain(name)
        try:
            provider = domain.get_option('id_provider')
        except SSSDConfig.NoOptionError:
            continue
        if provider == "ipa":
            domain.add_provider('ipa', 'autofs')
            try:
                location = domain.get_option('ipa_automount_location')
                sys.exit('An automount location is already configured')
            except SSSDConfig.NoOptionError:
                domain.set_option('ipa_automount_location', options.location)
                break

    if domain is None:
        sys.exit('SSSD is not configured.')

    sssdconfig.save_domain(domain)
    sssdconfig.write("/etc/sssd/sssd.conf")
    statestore.backup_state('autofs', 'sssd', True)

    sssd = ipaservices.service('sssd')
    sssd.restart()
    print "Restarting sssd, waiting for it to become available."
    wait_for_sssd()

def configure_autofs(fstore, statestore, autodiscover, server, options):
    """
    fstore: the FileStore to back up files in
    options.server: the IPA server to use
    options.location: the Automount location to use
    """
    if not autodiscover:
        ldap_uri = "ldap://%s" % server
    else:
        ldap_uri = "ldap:///%s" % api.env.basedn

    search_base = str(DN(('cn', options.location), api.env.container_automount, api.env.basedn))
    replacevars = {
        'MAP_OBJECT_CLASS': 'automountMap',
        'ENTRY_OBJECT_CLASS': 'automount',
        'MAP_ATTRIBUTE': 'automountMapName',
        'ENTRY_ATTRIBUTE': 'automountKey',
        'VALUE_ATTRIBUTE': 'automountInformation',
        'SEARCH_BASE': search_base,
        'LDAP_URI': ldap_uri,
    }

    ipautil.backup_config_and_replace_variables(fstore,
        AUTOFS_CONF, replacevars=replacevars)
    ipaservices.restore_context(AUTOFS_CONF)
    statestore.backup_state('autofs', 'sssd', False)

    print "Configured %s" % AUTOFS_CONF

def configure_autofs_common(fstore, statestore, options):
    autofs = ipaservices.knownservices.autofs
    statestore.backup_state('autofs', 'enabled', autofs.is_enabled())
    statestore.backup_state('autofs', 'running', autofs.is_running())
    try:
        autofs.restart()
        print "Started %s" % autofs.service_name
    except Exception, e:
        root_logger.error("%s failed to restart: %s", autofs.service_name, e)
    try:
        autofs.enable()
    except Exception, e:
        print "Failed to configure automatic startup of the %s daemon" % (autofs.service_name)
        root_logger.error("Failed to enable automatic startup of the %s daemon: %s" % (autofs.service_name, str(e)))

def uninstall(fstore, statestore):
    print "Restoring configuration"
    if fstore.has_file(AUTOFS_CONF):
        fstore.restore_file(AUTOFS_CONF)
    if fstore.has_file(NSSWITCH_CONF):
        fstore.restore_file(NSSWITCH_CONF)
    if fstore.has_file(AUTOFS_LDAP_AUTH):
        fstore.restore_file(AUTOFS_LDAP_AUTH)
    if fstore.has_file(NFS_CONF):
        fstore.restore_file(NFS_CONF)
    if fstore.has_file(IDMAPD_CONF):
        fstore.restore_file(IDMAPD_CONF)
    if statestore.has_state('autofs'):
        enabled = statestore.restore_state('autofs', 'enabled')
        running = statestore.restore_state('autofs', 'running')
        sssd = statestore.restore_state('autofs', 'sssd')
        autofs = ipaservices.knownservices.autofs
        if not enabled:
            autofs.disable()
        if not running:
            autofs.stop()
        if sssd:
            try:
                sssdconfig = SSSDConfig.SSSDConfig()
                sssdconfig.import_config()
                sssdconfig.deactivate_service('autofs')
                domains = sssdconfig.list_active_domains()
                for name in domains:
                    domain = sssdconfig.get_domain(name)
                    try:
                        provider = domain.get_option('id_provider')
                    except SSSDConfig.NoOptionError:
                        continue
                    if provider == "ipa":
                        domain.remove_option('ipa_automount_location')
                        domain.remove_provider('autofs')
                        break
                sssdconfig.save_domain(domain)
                sssdconfig.write("/etc/sssd/sssd.conf")
                sssd = ipaservices.service('sssd')
                sssd.restart()
                wait_for_sssd()
            except Exception, e:
                print 'Unable to restore SSSD configuration: %s' % str(e)
                root_logger.debug('Unable to restore SSSD configuration: %s' % str(e))
    if statestore.has_state('rpcidmapd'):
        enabled = statestore.restore_state('rpcidmapd', 'enabled')
        running = statestore.restore_state('rpcidmapd', 'running')
        rpcidmapd = ipaservices.knownservices.rpcidmapd
        if not enabled:
            rpcidmapd.disable()
        if not running:
            rpcidmapd.stop()
    if statestore.has_state('rpcgssd'):
        enabled = statestore.restore_state('rpcgssd', 'enabled')
        running = statestore.restore_state('rpcgssd', 'running')
        rpcgssd = ipaservices.knownservices.rpcgssd
        if not enabled:
            rpcgssd.disable()
        if not running:
            rpcgssd.stop()

    return 0

def configure_nfs(fstore, statestore):
    """
    Configure secure NFS
    """
    replacevars = {
        'SECURE_NFS': 'yes',
    }
    ipautil.backup_config_and_replace_variables(fstore,
        NFS_CONF, replacevars=replacevars)
    ipaservices.restore_context(NFS_CONF)

    print "Configured %s" % NFS_CONF

    replacevars = {
        'Domain': api.env.domain,
    }
    ipautil.backup_config_and_replace_variables(fstore,
        IDMAPD_CONF, replacevars=replacevars)
    ipaservices.restore_context(IDMAPD_CONF)

    print "Configured %s" % IDMAPD_CONF

    rpcidmapd = ipaservices.knownservices.rpcidmapd
    statestore.backup_state('rpcidmapd', 'enabled', rpcidmapd.is_enabled())
    statestore.backup_state('rpcidmapd', 'running', rpcidmapd.is_running())
    try:
        rpcidmapd.restart()
        print "Started %s" % rpcidmapd.service_name
    except Exception, e:
        root_logger.error("%s failed to restart: %s", rpcidmapd.service_name, e)
    try:
        rpcidmapd.enable()
    except Exception, e:
        print "Failed to configure automatic startup of the %s daemon" % (rpcidmapd.service_name)
        root_logger.error("Failed to enable automatic startup of the %s daemon: %s" % (rpcidmapd.service_name, str(e)))

    rpcgssd = ipaservices.knownservices.rpcgssd
    statestore.backup_state('rpcgssd', 'enabled', rpcgssd.is_enabled())
    statestore.backup_state('rpcgssd', 'running', rpcgssd.is_running())
    try:
        rpcgssd.restart()
        print "Started %s" % rpcgssd.service_name
    except Exception, e:
        root_logger.error("%s failed to restart: %s", rpcgssd.service_name, e)
    try:
        rpcgssd.enable()
    except Exception, e:
        print "Failed to configure automatic startup of the %s daemon" % (rpcgssd.service_name)
        root_logger.error("Failed to enable automatic startup of the %s daemon: %s" % (rpcgssd.service_name, str(e)))

def main():

    fstore = sysrestore.FileStore('/var/lib/ipa-client/sysrestore')
    statestore = sysrestore.StateFile('/var/lib/ipa-client/sysrestore')
    if not fstore.has_files():
        sys.exit('IPA client is not configured on this system.\n')

    options, args = parse_options()

    standard_logging_setup(
        '/var/log/ipaclient-install.log', verbose=False, debug=options.debug,
        filemode='a', console_format='%(message)s')

    cfg = dict(
        context='cli_installer',
        in_server=False,
        debug=options.debug,
        verbose=0,
    )

    api.bootstrap(**cfg)
    api.finalize()

    if options.uninstall:
        return uninstall(fstore, statestore)

    if statestore.has_state('autofs'):
        sys.exit('automount is already configured on this system.\n')

    autodiscover = False
    servers = []
    ds = ipadiscovery.IPADiscovery()
    if not options.server:
        print "Searching for IPA server..."
        ret = ds.search()
        root_logger.debug('Executing DNS discovery')
        if ret == ipadiscovery.NO_LDAP_SERVER:
            root_logger.debug('Autodiscovery did not find LDAP server')
            s = urlparse.urlsplit(api.env.xmlrpc_uri)
            server = [s.netloc]
            root_logger.debug('Setting server to %s' % s.netloc)
        else:
            autodiscover = True
            if not ds.servers:
                sys.exit('Autodiscovery was successful but didn\'t return a server')
            root_logger.debug('Autodiscovery success, possible servers %s' % ','.join(ds.servers))
            server = ds.servers[0]
    else:
        server = options.server
        root_logger.debug("Verifying that %s is an IPA server" % server)
        ldapret = ds.ipacheckldap(server, api.env.realm)
        if ldapret[0] == ipadiscovery.NO_ACCESS_TO_LDAP:
            print "Anonymous access to the LDAP server is disabled."
            print "Proceeding without strict verification."
            print "Note: This is not an error if anonymous access has been explicitly restricted."
        elif ldapret[0] != 0:
            sys.exit('Unable to confirm that %s is an IPA server' % server)

    if not autodiscover:
        print "IPA server: %s" % server
        root_logger.debug('Using fixed server %s' % server)
    else:
        print "IPA server: DNS discovery"
        root_logger.debug('Configuring to use DNS discovery')

    search_base = str(DN(('cn', options.location), api.env.container_automount, api.env.basedn))
    print "Location: %s" % options.location
    root_logger.debug('Using automount location %s' % options.location)

    # Verify that the location is valid
    (ccache_fd, ccache_name) = tempfile.mkstemp()
    os.close(ccache_fd)
    try:
        try:
            os.environ['KRB5CCNAME'] = ccache_name
            ipautil.run(['/usr/bin/kinit', '-k', '-t', '/etc/krb5.keytab', 'host/%s@%s' % (api.env.host, api.env.realm)])
        except ipautil.CalledProcessError, e:
            sys.exit("Failed to obtain host TGT.")
        # Now we have a TGT, connect to IPA
        try:
            api.Backend.xmlclient.connect()
        except errors.KerberosError, e:
            sys.exit('Cannot connect to the server due to ' + str(e))
        try:
            api.Command['automountlocation_show'](unicode(options.location))
        except errors.VersionError, e:
            sys.exit('This client is incompatible: ' + str(e))
        except errors.NotFound:
            sys.exit("Automount location '%s' does not exist" % options.location)
        except errors.PublicError, e:
            sys.exit("Cannot connect to the server due to generic error: %s" % str(e))
    finally:
        os.remove(ccache_name)

    if not options.unattended and not ipautil.user_input("Continue to configure the system with these values?", False):
        sys.exit("Installation aborted")

    try:
        configure_nsswitch(fstore, options)
        configure_nfs(fstore, statestore)
        if options.sssd:
            configure_autofs_sssd(fstore, statestore, autodiscover, options)
        else:
            configure_xml(fstore)
            configure_autofs(fstore, statestore, autodiscover, server, options)
        configure_autofs_common(fstore, statestore, options)
    except Exception, e:
        root_logger.debug('Raised exception %s' % e)
        print "Installation failed. Rolling back changes."
        uninstall(fstore, statestore)
        return 1

    return 0

try:
    if not os.geteuid()==0:
        sys.exit("\nMust be run as root\n")

    sys.exit(main())
except SystemExit, e:
    sys.exit(e)
except RuntimeError, e:
    sys.exit(e)
except (KeyboardInterrupt, EOFError):
    sys.exit(1)
