#!/usr/bin/python
# Authors:
#     Endi S. Dewata <edewata@redhat.com>
#
# 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; version 2 of the License.
#
# 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, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# Copyright (C) 2013 Red Hat, Inc.
# All rights reserved.
#

import grp
import os
import pwd
import shutil
import signal
import sys
from lxml import etree

import pki
import pki.server.upgrade


class ReplaceRandomNumberGenerator(pki.server.upgrade.PKIServerUpgradeScriptlet):

    def __init__(self):

        self.message = 'Replace random number generator'

        self.parser = etree.XMLParser(remove_blank_text=True)

    def upgrade_subsystem(self, instance, subsystem):

        context_xml = os.path.join(
            instance.base_dir,
            'webapps', subsystem.name,
            'META-INF', 'context.xml')

        if not os.path.exists(context_xml):
            self.create_context_xml(
                instance,
                subsystem.name,
                subsystem.name)

        document = etree.parse(context_xml, self.parser)

        self.add_manager(document)
        if subsystem.type >=10:
            self.update_authenticator(document)
        else:
            self.remove_authenticator(document)
            self.remove_realm(document)

        with open(context_xml, 'w') as f:
            f.write(etree.tostring(document, pretty_print=True))


    def upgrade_instance(self, instance):

        self.update_root_context_xml(instance)
        self.update_pki_context_xml(instance)


    def update_root_context_xml(self, instance):

        context_xml = os.path.join(
            instance.base_dir,
            'webapps', 'ROOT',
            'META-INF', 'context.xml')

        if not os.path.exists(context_xml):
            self.create_context_xml(instance, 'server', 'ROOT')

        document = etree.parse(context_xml, self.parser)

        self.add_manager(document)

        with open(context_xml, 'w') as f:
            f.write(etree.tostring(document, pretty_print=True))

    def update_pki_context_xml(self, instance):

        context_xml = os.path.join(
            instance.base_dir,
            'webapps', 'pki',
            'META-INF', 'context.xml')

        if not os.path.exists(context_xml):
            self.create_context_xml(instance, 'server', 'pki')

        document = etree.parse(context_xml, self.parser)

        self.add_manager(document)

        with open(context_xml, 'w') as f:
            f.write(etree.tostring(document, pretty_print=True))


    def create_context_xml(self, instance, pkg, context):

        uid = pwd.getpwnam('pkiuser').pw_uid
        gid = grp.getgrnam('pkiuser').gr_gid

        source = '/usr/share/pki/%s/webapps/%s/META-INF/context.xml' %\
            (pkg, context)

        meta_inf_dir = os.path.join(
            instance.base_dir,
            'webapps', context,
            'META-INF')
        context_xml = os.path.join(meta_inf_dir, 'context.xml')

        if not os.path.exists(meta_inf_dir):
            os.makedirs(meta_inf_dir)

        os.chown(meta_inf_dir, uid, gid)
        os.chmod(meta_inf_dir, 0770)

        if not os.path.exists(context_xml):
            shutil.copyfile(source, context_xml)

        os.chown(context_xml, uid, gid)
        os.chmod(context_xml, 0660)

    def add_manager(self, document):

        # Find existing manager
        context = document.getroot()
        manager = context.find('Manager')

        if manager is None:

            # Create new manager
            manager = etree.SubElement(context, 'Manager')

        # Update manager's attributes
        manager.set('secureRandomProvider', 'Mozilla-JSS')
        manager.set('secureRandomAlgorithm', 'pkcs11prng')


    def update_authenticator(self, document):

        context = document.getroot()
        valves = context.findall('Valve')
        authenticator = None

        # Find existing authenticator
        for valve in valves:
            className = valve.get('className')
            if className != 'com.netscape.cms.tomcat.SSLAuthenticatorWithFallback':
                continue

            # Found existing authenticator
            authenticator = valve
            break

        if authenticator is None:

            # Create new authenticator'
            authenticator = etree.SubElement(authenticator, 'Valve')
            authenticator.set('className',
                'com.netscape.cms.tomcat.SSLAuthenticatorWithFallback')

        # Update authenticator's attributes
        authenticator.set('secureRandomProvider', 'Mozilla-JSS')
        authenticator.set('secureRandomAlgorithm', 'pkcs11prng')

    def remove_authenticator(self, document):

        context = document.getroot()
        valves = context.findall('Valve')

        for valve in valves:
            className = valve.get('className')
            if className != 'com.netscape.cms.tomcat.SSLAuthenticatorWithFallback':
                continue
            context.remove(valve)

    def remove_realm(self, document):

        context = document.getroot()
        realms = context.findall('Realm')

        for realm in realms:
            className = realm.get('className')
            if className != 'com.netscape.cms.tomcat.ProxyRealm':
                continue
            context.remove(realm)
