#!/usr/bin/python
# Authors: Rob Crittenden <rcritten@redhat.com
#
# Copyright (C) 2013  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/>.
#

import os
import sys
import shutil
import tempfile
import time
import pwd
from optparse import OptionGroup
from ConfigParser import SafeConfigParser

from ipalib import api, errors
from ipapython import version
from ipapython.ipautil import run, write_tmp_file
from ipapython import admintool
from ipapython.config import IPAOptionParser
from ipapython.dn import DN
from ipaserver.install.dsinstance import realm_to_serverid, DS_USER
from ipaserver.install.replication import wait_for_task
from ipaserver.install import installutils
from ipapython import services as ipaservices
from ipapython import ipaldap
from ipalib.session import ISO8601_DATETIME_FMT
from ConfigParser import SafeConfigParser

"""
A test gpg can be generated list this:

# cat >keygen <<EOF
     %echo Generating a standard key
     Key-Type: RSA
     Key-Length: 2048
     Name-Real: IPA Backup
     Name-Comment: IPA Backup
     Name-Email: root@example.com
     Expire-Date: 0
     %pubring /root/backup.pub
     %secring /root/backup.sec
     %commit
     %echo done
EOF
# gpg --batch --gen-key keygen
# gpg --no-default-keyring --secret-keyring /root/backup.sec \
      --keyring /root/backup.pub --list-secret-keys
"""

BACKUP_DIR = '/var/lib/ipa/backup'


def encrypt_file(filename, keyring, remove_original=True):
    source = filename
    dest = filename + '.gpg'

    args = ['/usr/bin/gpg',
            '--batch',
            '--default-recipient-self',
            '-o', dest]

    if keyring is not None:
        args.append('--no-default-keyring')
        args.append('--keyring')
        args.append(keyring + '.pub')
        args.append('--secret-keyring')
        args.append(keyring + '.sec')

    args.append('-e')
    args.append(source)

    (stdout, stderr, rc) = run(args, raiseonerr=False)
    if rc != 0:
        raise admintool.ScriptError('gpg failed: %s' % stderr)

    if remove_original:
        os.unlink(source)

    return dest


class Backup(admintool.AdminTool):
    command_name = 'ipa-backup'
    log_file_name = '/var/log/ipabackup.log'

    usage = "%prog [options]"

    description = "Back up IPA files and databases."

    dirs = ('/usr/share/ipa/html',
        '/root/.pki',
        '/etc/pki-ca',
        '/etc/pki/pki-tomcat',
        '/etc/sysconfig/pki',
        '/etc/httpd/alias',
        '/var/lib/pki',
        '/var/lib/pki-ca',
        '/var/lib/ipa/sysrestore',
        '/var/lib/ipa-client/sysrestore',
        '/var/lib/sss/pubconf/krb5.include.d',
        '/var/lib/authconfig/last',
        '/var/lib/certmonger',
        '/var/lib/ipa',
        '/var/run/dirsrv',
        '/var/lock/dirsrv',
    )

    files = (
        '/etc/named.conf',
        '/etc/named.keytab',
        '/etc/resolv.conf',
        '/etc/sysconfig/pki-ca',
        '/etc/sysconfig/pki-tomcat',
        '/etc/sysconfig/dirsrv',
        '/etc/sysconfig/ntpd',
        '/etc/sysconfig/krb5kdc',
        '/etc/sysconfig/pki/ca/pki-ca',
        '/etc/sysconfig/authconfig',
        '/etc/pki/nssdb/cert8.db',
        '/etc/pki/nssdb/key3.db',
        '/etc/pki/nssdb/secmod.db',
        '/etc/nsswitch.conf',
        '/etc/krb5.keytab',
        '/etc/sssd/sssd.conf',
        '/etc/openldap/ldap.conf',
        '/etc/security/limits.conf',
        '/etc/httpd/conf/password.conf',
        '/etc/httpd/conf/ipa.keytab',
        '/etc/httpd/conf.d/ipa-pki-proxy.conf',
        '/etc/httpd/conf.d/ipa-rewrite.conf',
        '/etc/httpd/conf.d/nss.conf',
        '/etc/httpd/conf.d/ipa.conf',
        '/etc/ssh/sshd_config',
        '/etc/ssh/ssh_config',
        '/etc/krb5.conf',
        '/etc/group',
        '/etc/passwd',
        '/etc/ipa/ca.crt',
        '/etc/ipa/default.conf',
        '/etc/dirsrv/ds.keytab',
        '/etc/ntp.conf',
        '/etc/samba/smb.conf',
        '/etc/samba/samba.keytab',
        '/root/ca-agent.p12',
        '/root/cacert.p12',
        '/var/kerberos/krb5kdc/kdc.conf',
        '/etc/systemd/system/multi-user.target.wants/ipa.service',
        '/etc/systemd/system/multi-user.target.wants/sssd.service',
        '/etc/systemd/system/multi-user.target.wants/certmonger.service',
        '/etc/systemd/system/pki-tomcatd.target.wants/pki-tomcatd@pki-tomcat.service',
        '/var/run/ipa/services.list',
    )

    logs=(
      '/var/log/pki-ca',
      '/var/log/pki/',
      '/var/log/dirsrv/slapd-PKI-IPA',
      '/var/log/httpd',
      '/var/log/ipaserver-install.log',
      '/var/log/kadmind.log',
      '/var/log/pki-ca-install.log',
      '/var/log/messages',
      '/var/log/ipaclient-install.log',
      '/var/log/secure',
      '/var/log/ipaserver-uninstall.log',
      '/var/log/pki-ca-uninstall.log',
      '/var/log/ipaclient-uninstall.log',
      '/var/named/data/named.run',
    )

    def __init__(self, options, args):
        super(Backup, self).__init__(options, args)
        self._conn = None
        self.files = list(self.files)
        self.dirs = list(self.dirs)
        self.logs = list(self.logs)

    @classmethod
    def add_options(cls, parser):
        super(Backup, cls).add_options(parser, debug_option=True)

        parser.add_option("--gpg-keyring", dest="gpg_keyring",
            help="The gpg key name to be used (or full path)")
        parser.add_option("--gpg", dest="gpg", action="store_true",
          default=False, help="Encrypt the backup")
        parser.add_option("--data", dest="data_only", action="store_true",
            default=False, help="Backup only the data")
        parser.add_option("--logs", dest="logs", action="store_true",
            default=False, help="Include log files in backup")
        parser.add_option("--online", dest="online", action="store_true",
            default=False, help="Perform the LDAP backups online, for data only.")


    def setup_logging(self, log_file_mode='a'):
        super(Backup, self).setup_logging(log_file_mode='a')


    def validate_options(self):
        options = self.options
        super(Backup, self).validate_options(needs_root=True)
        installutils.check_server_configuration()

        if options.gpg_keyring is not None:
            if not os.path.exists(options.gpg_keyring + '.pub'):
                raise admintool.ScriptError('No such key %s' %
                    options.gpg_keyring)
            options.gpg = True

        if options.online and not options.data_only:
            self.option_parser.error("You cannot specify --online "
                "without --data")

        if options.gpg:
            tmpfd = write_tmp_file('encryptme')
            newfile = encrypt_file(tmpfd.name, options.gpg_keyring, False)
            os.unlink(newfile)

        if options.data_only and options.logs:
            self.option_parser.error("You cannot specify --data "
                "with --logs")


    def run(self):
        options = self.options
        super(Backup, self).run()

        api.bootstrap(in_server=False, context='backup')
        api.finalize()

        self.log.info("Preparing backup on %s", api.env.host)

        pent = pwd.getpwnam(DS_USER)

        self.top_dir = tempfile.mkdtemp("ipa")
        os.chown(self.top_dir, pent.pw_uid, pent.pw_gid)
        os.chmod(self.top_dir, 0750)
        self.dir = os.path.join(self.top_dir, "ipa")
        os.mkdir(self.dir, 0750)

        os.chown(self.dir, pent.pw_uid, pent.pw_gid)

        self.header = os.path.join(self.top_dir, 'header')

        cwd = os.getcwd()
        try:
            dirsrv = ipaservices.knownservices.dirsrv

            self.add_instance_specific_data()

            # We need the dirsrv running to get the list of services
            dirsrv.start(capture_output=False)

            self.get_connection()

            self.create_header(options.data_only)
            if options.data_only:
                if not options.online:
                    self.log.info('Stopping Directory Server')
                    dirsrv.stop(capture_output=False)
            else:
                self.log.info('Stopping IPA services')
                run(['ipactl', 'stop'])

            for instance in [realm_to_serverid(api.env.realm), 'PKI-IPA']:
                if os.path.exists('/var/lib/dirsrv/slapd-%s' % instance):
                    if os.path.exists('/var/lib/dirsrv/slapd-%s/db/ipaca' % instance):
                        self.db2ldif(instance, 'ipaca', online=options.online)
                    self.db2ldif(instance, 'userRoot', online=options.online)
                    self.db2bak(instance, online=options.online)
            if not options.data_only:
                self.file_backup(options)
            self.finalize_backup(options.data_only, options.gpg, options.gpg_keyring)

            if options.data_only:
                if not options.online:
                    self.log.info('Starting Directory Server')
                    dirsrv.start(capture_output=False)
            else:
                self.log.info('Starting IPA service')
                run(['ipactl', 'start'])

        finally:
            try:
                os.chdir(cwd)
            except Exception, e:
                self.log.error('Cannot change directory to %s: %s' % (cwd, e))
            shutil.rmtree(self.top_dir)


    def add_instance_specific_data(self):
        '''
        Add instance-specific files and directories.

        NOTE: this adds some things that may not get backed up, like the PKI-IPA
              instance.
        '''
        for dir in [
                '/etc/dirsrv/slapd-%s' % realm_to_serverid(api.env.realm),
                '/var/lib/dirsrv/scripts-%s' % realm_to_serverid(api.env.realm),
                '/var/lib/dirsrv/slapd-%s' % realm_to_serverid(api.env.realm),
                '/usr/lib64/dirsrv/slapd-PKI-IPA',
                '/usr/lib/dirsrv/slapd-PKI-IPA',
                '/etc/dirsrv/slapd-PKI-IPA',
                '/var/lib/dirsrv/slapd-PKI-IPA',
                self.__find_scripts_dir('PKI-IPA'),
            ]:
            if os.path.exists(dir):
                self.dirs.append(dir)

        for file in [
                '/etc/sysconfig/dirsrv-%s' % realm_to_serverid(api.env.realm),
                '/etc/sysconfig/dirsrv-PKI-IPA']:
            if os.path.exists(file):
                self.files.append(file)

        for log in [
              '/var/log/dirsrv/slapd-%s' % realm_to_serverid(api.env.realm),]:
            self.logs.append(log)


    def get_connection(self):
        '''
        Create an ldapi connection and bind to it using autobind as root.
        '''
        if self._conn is not None:
            return self._conn

        self._conn = ipaldap.IPAdmin(host=api.env.host,
                                    ldapi=True,
                                    protocol='ldapi',
                                    realm=api.env.realm)

        try:
            pw_name = pwd.getpwuid(os.geteuid()).pw_name
            self._conn.do_external_bind(pw_name)
        except Exception, e:
            self.log.error("Unable to bind to LDAP server %s: %s" %
                (self._conn.host, e))

        return self._conn


    def db2ldif(self, instance, backend, online=True):
        '''
        Create a LDIF backup of the data in this instance.

        If executed online create a task and wait for it to complete.

        For SELinux reasons this writes out to the 389-ds backup location
        and we move it.
        '''
        self.log.info('Backing up %s in %s to LDIF' % (backend, instance))

        now = time.localtime()
        cn = time.strftime('export_%Y_%m_%d_%H_%M_%S')
        dn = DN(('cn', cn), ('cn', 'export'), ('cn', 'tasks'), ('cn', 'config'))

        ldifname = '%s-%s.ldif' % (instance, backend)
        ldiffile = os.path.join(
            '/var/lib/dirsrv/slapd-%s/ldif' % instance,
            ldifname)

        if online:
            conn = self.get_connection()
            ent = conn.make_entry(
                dn,
                {
                    'objectClass': ['top', 'extensibleObject'],
                    'cn': [cn],
                    'nsInstance': [backend],
                    'nsFilename': [ldiffile],
                    'nsUseOneFile': ['true'],
                    'nsExportReplica': ['true'],
                }
            )

            try:
                conn.add_entry(ent)
            except Exception, e:
                raise admintool.ScriptError('Unable to add LDIF task: %s'
                    % e)

            self.log.info("Waiting for LDIF to finish")
            wait_for_task(conn, dn)
        else:
            args = ['%s/db2ldif' % self.__find_scripts_dir(instance),
                    '-r',
                    '-n', backend,
                    '-a', ldiffile]
            (stdout, stderr, rc) = run(args, raiseonerr=False)
            if rc != 0:
                self.log.critical("db2ldif failed: %s", stderr)

        # Move the LDIF backup to our location
        shutil.move(ldiffile, os.path.join(self.dir, ldifname))


    def db2bak(self, instance, online=True):
        '''
        Create a BAK backup of the data and changelog in this instance.

        If executed online create a task and wait for it to complete.
        '''
        self.log.info('Backing up %s' % instance)
        now = time.localtime()
        cn = time.strftime('backup_%Y_%m_%d_%H_%M_%S')
        dn = DN(('cn', cn), ('cn', 'backup'), ('cn', 'tasks'), ('cn', 'config'))

        bakdir = os.path.join('/var/lib/dirsrv/slapd-%s/bak/%s' % (instance, instance))

        if online:
            conn = self.get_connection()
            ent = conn.make_entry(
                dn,
                {
                    'objectClass': ['top', 'extensibleObject'],
                    'cn': [cn],
                    'nsInstance': ['userRoot'],
                    'nsArchiveDir': [bakdir],
                    'nsDatabaseType': ['ldbm database'],
                }
            )

            try:
                conn.add_entry(ent)
            except Exception, e:
                raise admintool.ScriptError('Unable to to add backup task: %s'
                    % e)

            self.log.info("Waiting for BAK to finish")
            wait_for_task(conn, dn)
        else:
            args = ['%s/db2bak' % self.__find_scripts_dir(instance), bakdir]
            (stdout, stderr, rc) = run(args, raiseonerr=False)
            if rc != 0:
                self.log.critical("db2bak failed: %s" % stderr)

        shutil.move(bakdir, self.dir)


    def file_backup(self, options):

        def verify_directories(dirs):
            return [s for s in dirs if os.path.exists(s)]

        self.log.info("Backing up files")
        args = ['tar',
                '--xattrs',
                '--selinux',
                '-czf',
                os.path.join(self.dir, 'files.tar')
               ]

        args.extend(verify_directories(self.dirs))
        args.extend(verify_directories(self.files))

        if options.logs:
            args.extend(verify_directories(self.logs))

        (stdout, stderr, rc) = run(args, raiseonerr=False)
        if rc != 0:
            raise admintool.ScriptError('tar returned non-zero %d: %s' % (rc, stdout))


    def create_header(self, data_only):
        '''
        Create the backup file header that contains the meta data about
        this particular backup.
        '''
        config = SafeConfigParser()
        config.add_section("ipa")
        if data_only:
            config.set('ipa', 'type', 'DATA')
        else:
            config.set('ipa', 'type', 'FULL')
        config.set('ipa', 'time', time.strftime(ISO8601_DATETIME_FMT, time.gmtime()))
        config.set('ipa', 'host', api.env.host)
        config.set('ipa', 'ipa_version', str(version.VERSION))
        config.set('ipa', 'version', '1')

        dn = DN(('cn', api.env.host), ('cn', 'masters'), ('cn', 'ipa'), ('cn', 'etc'), api.env.basedn)
        services_cns = []
        try:
            conn = self.get_connection()
            services = conn.get_entries(dn, conn.SCOPE_ONELEVEL)
        except errors.NetworkError:
            self.log.critical(
              "Unable to obtain list of master services, continuing anyway")
        except Exception, e:
            self.log.error("Failed to read services from '%s': %s" %
                (conn.host, e))
        else:
            services_cns = [s.single_value('cn') for s in services]

        config.set('ipa', 'services', ','.join(services_cns))
        with open(self.header, 'w') as fd:
            config.write(fd)


    def finalize_backup(self, data_only=False, encrypt=False, keyring=None):
        '''
        Create the final location of the backup files and move the files
        we've backed up there, optionally encrypting them.

        This is done in a couple of steps. We have a directory that
        contains the tarball of the files, a directory that contains
        the db2bak output and an LDIF.

        These, along with the header, are moved into a new subdirectory
        in /var/lib/ipa/backup.
        '''

        if data_only:
            backup_dir = os.path.join(BACKUP_DIR, time.strftime('ipa-data-%Y-%m-%d-%H-%M-%S'))
            filename = os.path.join(backup_dir, "ipa-data.tar")
        else:
            backup_dir = os.path.join(BACKUP_DIR, time.strftime('ipa-full-%Y-%m-%d-%H-%M-%S'))
            filename = os.path.join(backup_dir, "ipa-full.tar")

        os.mkdir(backup_dir, 0700)

        cwd = os.getcwd()
        os.chdir(self.dir)
        args = ['tar',
                '--xattrs',
                '--selinux',
                '-czf',
                filename,
                '.'
               ]
        (stdout, stderr, rc) = run(args, raiseonerr=False)
        if rc != 0:
            raise admintool.ScriptError('tar returned non-zero %d: %s' % (rc, stdout))

        if encrypt:
            self.log.info('Encrypting %s' % filename)
            filename = encrypt_file(filename, keyring)

        shutil.move(self.header, backup_dir)

    def __find_scripts_dir(self, instance):
        """
        IPA stores its 389-ds scripts in a different directory than dogtag
        does so we need to probe for it.
        """
        if instance != 'PKI-IPA':
            return os.path.join('/var/lib/dirsrv', 'scripts-%s' % instance)
        else:
            if sys.maxsize > 2**32:
                libpath = 'lib64'
            else:
                libpath = 'lib'
            return os.path.join('/usr', libpath, 'dirsrv', 'slapd-PKI-IPA')