samba-mirror/python/samba/samdb.py

# Unix SMB/CIFS implementation.
# Copyright (C) Jelmer Vernooij <jelmer@samba.org> 2007-2010
# Copyright (C) Matthias Dieter Wallnoefer 2009
#
# Based on the original in EJS:
# Copyright (C) Andrew Tridgell <tridge@samba.org> 2005
# Copyright (C) Giampaolo Lauria <lauria2@yahoo.com> 2011
#
# 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/>.
#

"""Convenience functions for using the SAM."""

import samba
import ldb
import time
import base64
import os
import re
from samba import dsdb, dsdb_dns
from samba.ndr import ndr_unpack, ndr_pack
from samba.dcerpc import drsblobs, misc
from samba.common import normalise_int32
from samba.common import get_bytes, cmp
from samba.dcerpc import security
from samba import is_ad_dc_built
import binascii

__docformat__ = "restructuredText"


def get_default_backend_store():
    return "tdb"

class SamDBError(Exception):
    pass

class SamDBNotFoundError(SamDBError):
    pass

class SamDB(samba.Ldb):
    """The SAM database."""

    hash_oid_name = {}
    hash_well_known = {}

    def __init__(self, url=None, lp=None, modules_dir=None, session_info=None,
                 credentials=None, flags=ldb.FLG_DONT_CREATE_DB,
                 options=None, global_schema=True,
                 auto_connect=True, am_rodc=None):
        self.lp = lp
        if not auto_connect:
            url = None
        elif url is None and lp is not None:
            url = lp.samdb_url()

        self.url = url

        super(SamDB, self).__init__(url=url, lp=lp, modules_dir=modules_dir,
                                    session_info=session_info, credentials=credentials, flags=flags,
                                    options=options)

        if global_schema:
            dsdb._dsdb_set_global_schema(self)

        if am_rodc is not None:
            dsdb._dsdb_set_am_rodc(self, am_rodc)

    def connect(self, url=None, flags=0, options=None):
        '''connect to the database'''
        if self.lp is not None and not os.path.exists(url):
            url = self.lp.private_path(url)
        self.url = url

        super(SamDB, self).connect(url=url, flags=flags,
                                   options=options)

    def am_rodc(self):
        '''return True if we are an RODC'''
        return dsdb._am_rodc(self)

    def am_pdc(self):
        '''return True if we are an PDC emulator'''
        return dsdb._am_pdc(self)

    def domain_dn(self):
        '''return the domain DN'''
        return str(self.get_default_basedn())

    def schema_dn(self):
        '''return the schema partition dn'''
        return str(self.get_schema_basedn())

    def disable_account(self, search_filter):
        """Disables an account

        :param search_filter: LDAP filter to find the user (eg
            samccountname=name)
        """

        flags = samba.dsdb.UF_ACCOUNTDISABLE
        self.toggle_userAccountFlags(search_filter, flags, on=True)

    def enable_account(self, search_filter):
        """Enables an account

        :param search_filter: LDAP filter to find the user (eg
            samccountname=name)
        """

        flags = samba.dsdb.UF_ACCOUNTDISABLE | samba.dsdb.UF_PASSWD_NOTREQD
        self.toggle_userAccountFlags(search_filter, flags, on=False)

    def toggle_userAccountFlags(self, search_filter, flags, flags_str=None,
                                on=True, strict=False):
        """Toggle_userAccountFlags

        :param search_filter: LDAP filter to find the user (eg
            samccountname=name)
        :param flags: samba.dsdb.UF_* flags
        :param on: on=True (default) => set, on=False => unset
        :param strict: strict=False (default) ignore if no action is needed
                 strict=True raises an Exception if...
        """
        res = self.search(base=self.domain_dn(), scope=ldb.SCOPE_SUBTREE,
                          expression=search_filter, attrs=["userAccountControl"])
        if len(res) == 0:
                raise Exception("Unable to find account where '%s'" % search_filter)
        assert(len(res) == 1)
        account_dn = res[0].dn

        old_uac = int(res[0]["userAccountControl"][0])
        if on:
            if strict and (old_uac & flags):
                error = "Account flag(s) '%s' already set" % flags_str
                raise Exception(error)

            new_uac = old_uac | flags
        else:
            if strict and not (old_uac & flags):
                error = "Account flag(s) '%s' already unset" % flags_str
                raise Exception(error)

            new_uac = old_uac & ~flags

        if old_uac == new_uac:
            return

        mod = """
dn: %s
changetype: modify
delete: userAccountControl
userAccountControl: %u
add: userAccountControl
userAccountControl: %u
""" % (account_dn, old_uac, new_uac)
        self.modify_ldif(mod)

    def force_password_change_at_next_login(self, search_filter):
        """Forces a password change at next login

        :param search_filter: LDAP filter to find the user (eg
            samccountname=name)
        """
        res = self.search(base=self.domain_dn(), scope=ldb.SCOPE_SUBTREE,
                          expression=search_filter, attrs=[])
        if len(res) == 0:
                raise Exception('Unable to find user "%s"' % search_filter)
        assert(len(res) == 1)
        user_dn = res[0].dn

        mod = """
dn: %s
changetype: modify
replace: pwdLastSet
pwdLastSet: 0
""" % (user_dn)
        self.modify_ldif(mod)

    def unlock_account(self, search_filter):
        """Unlock a user account by resetting lockoutTime to 0.
        This does also reset the badPwdCount to 0.

        :param search_filter: LDAP filter to find the user (e.g.
            sAMAccountName=username)
        """
        res = self.search(base=self.domain_dn(),
                          scope=ldb.SCOPE_SUBTREE,
                          expression=search_filter,
                          attrs=[])
        if len(res) == 0:
            raise SamDBNotFoundError('Unable to find user "%s"' % search_filter)
        if len(res) != 1:
            raise SamDBError('User "%s" is not unique' % search_filter)
        user_dn = res[0].dn

        mod = """
dn: %s
changetype: modify
replace: lockoutTime
lockoutTime: 0
""" % (user_dn)
        self.modify_ldif(mod)

    def newgroup(self, groupname, groupou=None, grouptype=None,
                 description=None, mailaddress=None, notes=None, sd=None,
                 gidnumber=None, nisdomain=None):
        """Adds a new group with additional parameters

        :param groupname: Name of the new group
        :param grouptype: Type of the new group
        :param description: Description of the new group
        :param mailaddress: Email address of the new group
        :param notes: Notes of the new group
        :param gidnumber: GID Number of the new group
        :param nisdomain: NIS Domain Name of the new group
        :param sd: security descriptor of the object
        """

        group_dn = "CN=%s,%s,%s" % (groupname, (groupou or "CN=Users"), self.domain_dn())

        # The new user record. Note the reliance on the SAMLDB module which
        # fills in the default information
        ldbmessage = {"dn": group_dn,
                      "sAMAccountName": groupname,
                      "objectClass": "group"}

        if grouptype is not None:
            ldbmessage["groupType"] = normalise_int32(grouptype)

        if description is not None:
            ldbmessage["description"] = description

        if mailaddress is not None:
            ldbmessage["mail"] = mailaddress

        if notes is not None:
            ldbmessage["info"] = notes

        if gidnumber is not None:
            ldbmessage["gidNumber"] = normalise_int32(gidnumber)

        if nisdomain is not None:
            ldbmessage["msSFU30Name"] = groupname
            ldbmessage["msSFU30NisDomain"] = nisdomain

        if sd is not None:
            ldbmessage["nTSecurityDescriptor"] = ndr_pack(sd)

        self.add(ldbmessage)

    def deletegroup(self, groupname):
        """Deletes a group

        :param groupname: Name of the target group
        """

        groupfilter = "(&(sAMAccountName=%s)(objectCategory=%s,%s))" % (ldb.binary_encode(groupname), "CN=Group,CN=Schema,CN=Configuration", self.domain_dn())
        self.transaction_start()
        try:
            targetgroup = self.search(base=self.domain_dn(), scope=ldb.SCOPE_SUBTREE,
                                      expression=groupfilter, attrs=[])
            if len(targetgroup) == 0:
                raise Exception('Unable to find group "%s"' % groupname)
            assert(len(targetgroup) == 1)
            self.delete(targetgroup[0].dn)
        except:
            self.transaction_cancel()
            raise
        else:
            self.transaction_commit()

    def group_member_filter(self, member, member_types):
        filter = ""

        all_member_types = [ 'user',
                             'group',
                             'computer',
                             'serviceaccount',
                             'contact',
                           ]

        if 'all' in member_types:
            member_types = all_member_types

        for member_type in member_types:
            if member_type not in all_member_types:
                raise Exception('Invalid group member type "%s". '
                                'Valid types are %s and all.' %
                                (member_type, ", ".join(all_member_types)))

        if 'user' in member_types:
            filter += ('(&(sAMAccountName=%s)(samAccountType=%d))' %
                       (ldb.binary_encode(member), dsdb.ATYPE_NORMAL_ACCOUNT))
        if 'group' in member_types:
            filter += ('(&(sAMAccountName=%s)'
                       '(objectClass=group)'
                       '(!(groupType:1.2.840.113556.1.4.803:=1)))' %
                       ldb.binary_encode(member))
        if 'computer' in member_types:
            samaccountname = member
            if member[-1] != '$':
                samaccountname = "%s$" % member
            filter += ('(&(samAccountType=%d)'
                       '(!(objectCategory=msDS-ManagedServiceAccount))'
                       '(sAMAccountName=%s))' %
                       (dsdb.ATYPE_WORKSTATION_TRUST,
                        ldb.binary_encode(samaccountname)))
        if 'serviceaccount' in member_types:
            samaccountname = member
            if member[-1] != '$':
                samaccountname = "%s$" % member
            filter += ('(&(samAccountType=%d)'
                       '(objectCategory=msDS-ManagedServiceAccount)'
                       '(sAMAccountName=%s))' %
                       (dsdb.ATYPE_WORKSTATION_TRUST,
                        ldb.binary_encode(samaccountname)))
        if 'contact' in member_types:
            filter += ('(&(objectCategory=Person)(!(objectSid=*))(name=%s))' %
                       ldb.binary_encode(member))

        filter = "(|%s)" % filter

        return filter

    def add_remove_group_members(self, groupname, members,
                                 add_members_operation=True,
                                 member_types=[ 'user', 'group', 'computer' ],
                                 member_base_dn=None):
        """Adds or removes group members

        :param groupname: Name of the target group
        :param members: list of group members
        :param add_members_operation: Defines if its an add or remove
            operation
        """

        groupfilter = "(&(sAMAccountName=%s)(objectCategory=%s,%s))" % (
            ldb.binary_encode(groupname), "CN=Group,CN=Schema,CN=Configuration", self.domain_dn())

        self.transaction_start()
        try:
            targetgroup = self.search(base=self.domain_dn(), scope=ldb.SCOPE_SUBTREE,
                                      expression=groupfilter, attrs=['member'])
            if len(targetgroup) == 0:
                raise Exception('Unable to find group "%s"' % groupname)
            assert(len(targetgroup) == 1)

            modified = False

            addtargettogroup = """
dn: %s
changetype: modify
""" % (str(targetgroup[0].dn))

            for member in members:
                targetmember_dn = None
                if member_base_dn is None:
                    member_base_dn = self.domain_dn()

                try:
                    membersid = security.dom_sid(member)
                    targetmember_dn = "<SID=%s>" % str(membersid)
                except TypeError as e:
                    pass

                if targetmember_dn is None:
                    try:
                        member_dn = ldb.Dn(self, member)
                        if member_dn.get_linearized() == member_dn.extended_str(1):
                            full_member_dn = self.normalize_dn_in_domain(member_dn)
                        else:
                            full_member_dn = member_dn
                        targetmember_dn = full_member_dn.extended_str(1)
                    except ValueError as e:
                        pass

                if targetmember_dn is None:
                    filter = self.group_member_filter(member, member_types)
                    targetmember = self.search(base=member_base_dn,
                                               scope=ldb.SCOPE_SUBTREE,
                                               expression=filter,
                                               attrs=[])

                    if len(targetmember) > 1:
                        targetmemberlist_str = ""
                        for msg in targetmember:
                            targetmemberlist_str += "%s\n" % msg.get("dn")
                        raise Exception('Found multiple results for "%s":\n%s' %
                                        (member, targetmemberlist_str))
                    if len(targetmember) != 1:
                        raise Exception('Unable to find "%s". Operation cancelled.' % member)
                    targetmember_dn = targetmember[0].dn.extended_str(1)

                if add_members_operation is True and (targetgroup[0].get('member') is None or get_bytes(targetmember_dn) not in [str(x) for x in targetgroup[0]['member']]):
                    modified = True
                    addtargettogroup += """add: member
member: %s
""" % (str(targetmember_dn))

                elif add_members_operation is False and (targetgroup[0].get('member') is not None and get_bytes(targetmember_dn) in targetgroup[0]['member']):
                    modified = True
                    addtargettogroup += """delete: member
member: %s
""" % (str(targetmember_dn))

            if modified is True:
                self.modify_ldif(addtargettogroup)

        except:
            self.transaction_cancel()
            raise
        else:
            self.transaction_commit()

    def prepare_attr_replace(self, msg, old, attr_name, value):
        """Changes the MessageElement with the given attr_name of the
        given Message. If the value is "" set an empty value and the flag
        FLAG_MOD_DELETE, otherwise set the new value and FLAG_MOD_REPLACE.
        If the value is None or the Message contains the attr_name with this
        value, nothing will changed."""
        # skip unchanged attribute
        if value is None:
            return
        if attr_name in old and str(value) == str(old[attr_name]):
            return

        # remove attribute
        if len(value) == 0:
            if attr_name in old:
                el = ldb.MessageElement([], ldb.FLAG_MOD_DELETE, attr_name)
                msg.add(el)
            return

        # change attribute
        el = ldb.MessageElement(value, ldb.FLAG_MOD_REPLACE, attr_name)
        msg.add(el)

    def fullname_from_names(self, given_name=None, initials=None, surname=None,
                            old_attrs={}, fallback_default=""):
        """Prepares new combined fullname, using the name parts.
        Used for things like displayName or cn.
        Use the original name values, if no new one is specified."""

        attrs = {"givenName": given_name,
                 "initials": initials,
                 "sn": surname}

        # if the attribute is not specified, try to use the old one
        for attr_name, attr_value in attrs.items():
            if attr_value == None and attr_name in old_attrs:
                attrs[attr_name] = str(old_attrs[attr_name])

        # add '.' to initials if initals are not None and not "" and if the initials
        # don't have already a '.' at the end
        if attrs["initials"] and not attrs["initials"].endswith('.'):
            attrs["initials"] += '.'

        # remove empty values (None and '')
        attrs_values = list(filter(None, attrs.values()))

        # fullname is the combination of not-empty values as string, separated by ' '
        fullname = ' '.join(attrs_values)

        if fullname == '':
            return fallback_default

        return fullname

    def newuser(self, username, password,
                force_password_change_at_next_login_req=False,
                useusernameascn=False, userou=None, surname=None, givenname=None,
                initials=None, profilepath=None, scriptpath=None, homedrive=None,
                homedirectory=None, jobtitle=None, department=None, company=None,
                description=None, mailaddress=None, internetaddress=None,
                telephonenumber=None, physicaldeliveryoffice=None, sd=None,
                setpassword=True, uidnumber=None, gidnumber=None, gecos=None,
                loginshell=None, uid=None, nisdomain=None, unixhome=None,
                smartcard_required=False):
        """Adds a new user with additional parameters

        :param username: Name of the new user
        :param password: Password for the new user
        :param force_password_change_at_next_login_req: Force password change
        :param useusernameascn: Use username as cn rather that firstname +
            initials + lastname
        :param userou: Object container (without domainDN postfix) for new user
        :param surname: Surname of the new user
        :param givenname: First name of the new user
        :param initials: Initials of the new user
        :param profilepath: Profile path of the new user
        :param scriptpath: Logon script path of the new user
        :param homedrive: Home drive of the new user
        :param homedirectory: Home directory of the new user
        :param jobtitle: Job title of the new user
        :param department: Department of the new user
        :param company: Company of the new user
        :param description: of the new user
        :param mailaddress: Email address of the new user
        :param internetaddress: Home page of the new user
        :param telephonenumber: Phone number of the new user
        :param physicaldeliveryoffice: Office location of the new user
        :param sd: security descriptor of the object
        :param setpassword: optionally disable password reset
        :param uidnumber: RFC2307 Unix numeric UID of the new user
        :param gidnumber: RFC2307 Unix primary GID of the new user
        :param gecos: RFC2307 Unix GECOS field of the new user
        :param loginshell: RFC2307 Unix login shell of the new user
        :param uid: RFC2307 Unix username of the new user
        :param nisdomain: RFC2307 Unix NIS domain of the new user
        :param unixhome: RFC2307 Unix home directory of the new user
        :param smartcard_required: set the UF_SMARTCARD_REQUIRED bit of the new user
        """

        displayname = self.fullname_from_names(given_name=givenname,
                                               initials=initials,
                                               surname=surname)
        cn = username
        if useusernameascn is None and displayname != "":
            cn = displayname

        user_dn = "CN=%s,%s,%s" % (cn, (userou or "CN=Users"), self.domain_dn())

        dnsdomain = ldb.Dn(self, self.domain_dn()).canonical_str().replace("/", "")
        user_principal_name = "%s@%s" % (username, dnsdomain)
        # The new user record. Note the reliance on the SAMLDB module which
        # fills in the default information
        ldbmessage = {"dn": user_dn,
                      "sAMAccountName": username,
                      "userPrincipalName": user_principal_name,
                      "objectClass": "user"}

        if smartcard_required:
            ldbmessage["userAccountControl"] = str(dsdb.UF_NORMAL_ACCOUNT |
                                                   dsdb.UF_SMARTCARD_REQUIRED)
            setpassword = False

        if surname is not None:
            ldbmessage["sn"] = surname

        if givenname is not None:
            ldbmessage["givenName"] = givenname

        if displayname != "":
            ldbmessage["displayName"] = displayname
            ldbmessage["name"] = displayname

        if initials is not None:
            ldbmessage["initials"] = '%s.' % initials

        if profilepath is not None:
            ldbmessage["profilePath"] = profilepath

        if scriptpath is not None:
            ldbmessage["scriptPath"] = scriptpath

        if homedrive is not None:
            ldbmessage["homeDrive"] = homedrive

        if homedirectory is not None:
            ldbmessage["homeDirectory"] = homedirectory

        if jobtitle is not None:
            ldbmessage["title"] = jobtitle

        if department is not None:
            ldbmessage["department"] = department

        if company is not None:
            ldbmessage["company"] = company

        if description is not None:
            ldbmessage["description"] = description

        if mailaddress is not None:
            ldbmessage["mail"] = mailaddress

        if internetaddress is not None:
            ldbmessage["wWWHomePage"] = internetaddress

        if telephonenumber is not None:
            ldbmessage["telephoneNumber"] = telephonenumber

        if physicaldeliveryoffice is not None:
            ldbmessage["physicalDeliveryOfficeName"] = physicaldeliveryoffice

        if sd is not None:
            ldbmessage["nTSecurityDescriptor"] = ndr_pack(sd)

        ldbmessage2 = None
        if any(map(lambda b: b is not None, (uid, uidnumber, gidnumber, gecos,
                                             loginshell, nisdomain, unixhome))):
            ldbmessage2 = ldb.Message()
            ldbmessage2.dn = ldb.Dn(self, user_dn)
            if uid is not None:
                ldbmessage2["uid"] = ldb.MessageElement(str(uid), ldb.FLAG_MOD_REPLACE, 'uid')
            if uidnumber is not None:
                ldbmessage2["uidNumber"] = ldb.MessageElement(str(uidnumber), ldb.FLAG_MOD_REPLACE, 'uidNumber')
            if gidnumber is not None:
                ldbmessage2["gidNumber"] = ldb.MessageElement(str(gidnumber), ldb.FLAG_MOD_REPLACE, 'gidNumber')
            if gecos is not None:
                ldbmessage2["gecos"] = ldb.MessageElement(str(gecos), ldb.FLAG_MOD_REPLACE, 'gecos')
            if loginshell is not None:
                ldbmessage2["loginShell"] = ldb.MessageElement(str(loginshell), ldb.FLAG_MOD_REPLACE, 'loginShell')
            if unixhome is not None:
                ldbmessage2["unixHomeDirectory"] = ldb.MessageElement(
                    str(unixhome), ldb.FLAG_MOD_REPLACE, 'unixHomeDirectory')
            if nisdomain is not None:
                ldbmessage2["msSFU30NisDomain"] = ldb.MessageElement(
                    str(nisdomain), ldb.FLAG_MOD_REPLACE, 'msSFU30NisDomain')
                ldbmessage2["msSFU30Name"] = ldb.MessageElement(
                    str(username), ldb.FLAG_MOD_REPLACE, 'msSFU30Name')
                ldbmessage2["unixUserPassword"] = ldb.MessageElement(
                    'ABCD!efgh12345$67890', ldb.FLAG_MOD_REPLACE,
                    'unixUserPassword')

        self.transaction_start()
        try:
            self.add(ldbmessage)
            if ldbmessage2:
                self.modify(ldbmessage2)

            # Sets the password for it
            if setpassword:
                self.setpassword(("(distinguishedName=%s)" %
                                  ldb.binary_encode(user_dn)),
                                 password,
                                 force_password_change_at_next_login_req)
        except:
            self.transaction_cancel()
            raise
        else:
            self.transaction_commit()

    def newcontact(self,
                   fullcontactname=None,
                   ou=None,
                   surname=None,
                   givenname=None,
                   initials=None,
                   displayname=None,
                   jobtitle=None,
                   department=None,
                   company=None,
                   description=None,
                   mailaddress=None,
                   internetaddress=None,
                   telephonenumber=None,
                   mobilenumber=None,
                   physicaldeliveryoffice=None):
        """Adds a new contact with additional parameters

        :param fullcontactname: Optional full name of the new contact
        :param ou: Object container for new contact
        :param surname: Surname of the new contact
        :param givenname: First name of the new contact
        :param initials: Initials of the new contact
        :param displayname: displayName of the new contact
        :param jobtitle: Job title of the new contact
        :param department: Department of the new contact
        :param company: Company of the new contact
        :param description: Description of the new contact
        :param mailaddress: Email address of the new contact
        :param internetaddress: Home page of the new contact
        :param telephonenumber: Phone number of the new contact
        :param mobilenumber: Primary mobile number of the new contact
        :param physicaldeliveryoffice: Office location of the new contact
        """

        # Prepare the contact name like the RSAT, using the name parts.
        cn = self.fullname_from_names(given_name=givenname,
                                      initials=initials,
                                      surname=surname)

        # Use the specified fullcontactname instead of the previously prepared
        # contact name, if it is specified.
        # This is similar to the "Full name" value of the RSAT.
        if fullcontactname is not None:
            cn = fullcontactname

        if fullcontactname is None and cn == "":
            raise Exception('No name for contact specified')

        contactcontainer_dn = self.domain_dn()
        if ou:
            contactcontainer_dn = self.normalize_dn_in_domain(ou)

        contact_dn = "CN=%s,%s" % (cn, contactcontainer_dn)

        ldbmessage = {"dn": contact_dn,
                      "objectClass": "contact",
                      }

        if surname is not None:
            ldbmessage["sn"] = surname

        if givenname is not None:
            ldbmessage["givenName"] = givenname

        if displayname is not None:
            ldbmessage["displayName"] = displayname

        if initials is not None:
            ldbmessage["initials"] = '%s.' % initials

        if jobtitle is not None:
            ldbmessage["title"] = jobtitle

        if department is not None:
            ldbmessage["department"] = department

        if company is not None:
            ldbmessage["company"] = company

        if description is not None:
            ldbmessage["description"] = description

        if mailaddress is not None:
            ldbmessage["mail"] = mailaddress

        if internetaddress is not None:
            ldbmessage["wWWHomePage"] = internetaddress

        if telephonenumber is not None:
            ldbmessage["telephoneNumber"] = telephonenumber

        if mobilenumber is not None:
            ldbmessage["mobile"] = mobilenumber

        if physicaldeliveryoffice is not None:
            ldbmessage["physicalDeliveryOfficeName"] = physicaldeliveryoffice

        self.add(ldbmessage)

        return cn

    def newcomputer(self, computername, computerou=None, description=None,
                    prepare_oldjoin=False, ip_address_list=None,
                    service_principal_name_list=None):
        """Adds a new user with additional parameters

        :param computername: Name of the new computer
        :param computerou: Object container for new computer
        :param description: Description of the new computer
        :param prepare_oldjoin: Preset computer password for oldjoin mechanism
        :param ip_address_list: ip address list for DNS A or AAAA record
        :param service_principal_name_list: string list of servicePincipalName
        """

        cn = re.sub(r"\$$", "", computername)
        if cn.count('$'):
            raise Exception('Illegal computername "%s"' % computername)
        samaccountname = "%s$" % cn

        computercontainer_dn = "CN=Computers,%s" % self.domain_dn()
        if computerou:
            computercontainer_dn = self.normalize_dn_in_domain(computerou)

        computer_dn = "CN=%s,%s" % (cn, computercontainer_dn)

        ldbmessage = {"dn": computer_dn,
                      "sAMAccountName": samaccountname,
                      "objectClass": "computer",
                      }

        if description is not None:
            ldbmessage["description"] = description

        if service_principal_name_list:
            ldbmessage["servicePrincipalName"] = service_principal_name_list

        accountcontrol = str(dsdb.UF_WORKSTATION_TRUST_ACCOUNT |
                             dsdb.UF_ACCOUNTDISABLE)
        if prepare_oldjoin:
            accountcontrol = str(dsdb.UF_WORKSTATION_TRUST_ACCOUNT)
        ldbmessage["userAccountControl"] = accountcontrol

        if ip_address_list:
            ldbmessage['dNSHostName'] = '{}.{}'.format(
                cn, self.domain_dns_name())

        self.transaction_start()
        try:
            self.add(ldbmessage)

            if prepare_oldjoin:
                password = cn.lower()
                self.setpassword(("(distinguishedName=%s)" %
                                  ldb.binary_encode(computer_dn)),
                                 password, False)
        except:
            self.transaction_cancel()
            raise
        else:
            self.transaction_commit()

    def deleteuser(self, username):
        """Deletes a user

        :param username: Name of the target user
        """

        filter = "(&(sAMAccountName=%s)(objectCategory=%s,%s))" % (ldb.binary_encode(username), "CN=Person,CN=Schema,CN=Configuration", self.domain_dn())
        self.transaction_start()
        try:
            target = self.search(base=self.domain_dn(), scope=ldb.SCOPE_SUBTREE,
                                 expression=filter, attrs=[])
            if len(target) == 0:
                raise Exception('Unable to find user "%s"' % username)
            assert(len(target) == 1)
            self.delete(target[0].dn)
        except:
            self.transaction_cancel()
            raise
        else:
            self.transaction_commit()

    def setpassword(self, search_filter, password,
                    force_change_at_next_login=False, username=None):
        """Sets the password for a user

        :param search_filter: LDAP filter to find the user (eg
            samccountname=name)
        :param password: Password for the user
        :param force_change_at_next_login: Force password change
        """
        self.transaction_start()
        try:
            res = self.search(base=self.domain_dn(), scope=ldb.SCOPE_SUBTREE,
                              expression=search_filter, attrs=[])
            if len(res) == 0:
                raise Exception('Unable to find user "%s"' % (username or search_filter))
            if len(res) > 1:
                raise Exception('Matched %u multiple users with filter "%s"' % (len(res), search_filter))
            user_dn = res[0].dn
            if not isinstance(password, str):
                pw = password.decode('utf-8')
            else:
                pw = password
            pw = ('"' + pw + '"').encode('utf-16-le')
            setpw = """
dn: %s
changetype: modify
replace: unicodePwd
unicodePwd:: %s
""" % (user_dn, base64.b64encode(pw).decode('utf-8'))

            self.modify_ldif(setpw)

            if force_change_at_next_login:
                self.force_password_change_at_next_login(
                    "(distinguishedName=" + str(user_dn) + ")")

            #  modify the userAccountControl to remove the disabled bit
            self.enable_account(search_filter)
        except:
            self.transaction_cancel()
            raise
        else:
            self.transaction_commit()

    def setexpiry(self, search_filter, expiry_seconds, no_expiry_req=False):
        """Sets the account expiry for a user

        :param search_filter: LDAP filter to find the user (eg
            samaccountname=name)
        :param expiry_seconds: expiry time from now in seconds
        :param no_expiry_req: if set, then don't expire password
        """
        self.transaction_start()
        try:
            res = self.search(base=self.domain_dn(), scope=ldb.SCOPE_SUBTREE,
                              expression=search_filter,
                              attrs=["userAccountControl", "accountExpires"])
            if len(res) == 0:
                raise Exception('Unable to find user "%s"' % search_filter)
            assert(len(res) == 1)
            user_dn = res[0].dn

            userAccountControl = int(res[0]["userAccountControl"][0])
            accountExpires     = int(res[0]["accountExpires"][0])
            if no_expiry_req:
                userAccountControl = userAccountControl | 0x10000
                accountExpires = 0
            else:
                userAccountControl = userAccountControl & ~0x10000
                accountExpires = samba.unix2nttime(expiry_seconds + int(time.time()))

            setexp = """
dn: %s
changetype: modify
replace: userAccountControl
userAccountControl: %u
replace: accountExpires
accountExpires: %u
""" % (user_dn, userAccountControl, accountExpires)

            self.modify_ldif(setexp)
        except:
            self.transaction_cancel()
            raise
        else:
            self.transaction_commit()

    def set_domain_sid(self, sid):
        """Change the domain SID used by this LDB.

        :param sid: The new domain sid to use.
        """
        dsdb._samdb_set_domain_sid(self, sid)

    def get_domain_sid(self):
        """Read the domain SID used by this LDB. """
        return dsdb._samdb_get_domain_sid(self)

    domain_sid = property(get_domain_sid, set_domain_sid,
                          doc="SID for the domain")

    def set_invocation_id(self, invocation_id):
        """Set the invocation id for this SamDB handle.

        :param invocation_id: GUID of the invocation id.
        """
        dsdb._dsdb_set_ntds_invocation_id(self, invocation_id)

    def get_invocation_id(self):
        """Get the invocation_id id"""
        return dsdb._samdb_ntds_invocation_id(self)

    invocation_id = property(get_invocation_id, set_invocation_id,
                             doc="Invocation ID GUID")

    def get_oid_from_attid(self, attid):
        return dsdb._dsdb_get_oid_from_attid(self, attid)

    def get_attid_from_lDAPDisplayName(self, ldap_display_name,
                                       is_schema_nc=False):
        '''return the attribute ID for a LDAP attribute as an integer as found in DRSUAPI'''
        return dsdb._dsdb_get_attid_from_lDAPDisplayName(self,
                                                         ldap_display_name, is_schema_nc)

    def get_syntax_oid_from_lDAPDisplayName(self, ldap_display_name):
        '''return the syntax OID for a LDAP attribute as a string'''
        return dsdb._dsdb_get_syntax_oid_from_lDAPDisplayName(self, ldap_display_name)

    def get_systemFlags_from_lDAPDisplayName(self, ldap_display_name):
        '''return the systemFlags for a LDAP attribute as a integer'''
        return dsdb._dsdb_get_systemFlags_from_lDAPDisplayName(self, ldap_display_name)

    def get_linkId_from_lDAPDisplayName(self, ldap_display_name):
        '''return the linkID for a LDAP attribute as a integer'''
        return dsdb._dsdb_get_linkId_from_lDAPDisplayName(self, ldap_display_name)

    def get_lDAPDisplayName_by_attid(self, attid):
        '''return the lDAPDisplayName from an integer DRS attribute ID'''
        return dsdb._dsdb_get_lDAPDisplayName_by_attid(self, attid)

    def get_backlink_from_lDAPDisplayName(self, ldap_display_name):
        '''return the attribute name of the corresponding backlink from the name
        of a forward link attribute. If there is no backlink return None'''
        return dsdb._dsdb_get_backlink_from_lDAPDisplayName(self, ldap_display_name)

    def set_ntds_settings_dn(self, ntds_settings_dn):
        """Set the NTDS Settings DN, as would be returned on the dsServiceName
        rootDSE attribute.

        This allows the DN to be set before the database fully exists

        :param ntds_settings_dn: The new DN to use
        """
        dsdb._samdb_set_ntds_settings_dn(self, ntds_settings_dn)

    def get_ntds_GUID(self):
        """Get the NTDS objectGUID"""
        return dsdb._samdb_ntds_objectGUID(self)

    def get_timestr(self):
        """Get the current time as generalized time string"""
        res = self.search(base="",
                          scope=ldb.SCOPE_BASE,
                          attrs=["currentTime"])
        return str(res[0]["currentTime"][0])

    def get_time(self):
        """Get the current time as UNIX time"""
        return ldb.string_to_time(self.get_timestr())

    def get_nttime(self):
        """Get the current time as NT time"""
        return samba.unix2nttime(self.get_time())

    def server_site_name(self):
        """Get the server site name"""
        return dsdb._samdb_server_site_name(self)

    def host_dns_name(self):
        """return the DNS name of this host"""
        res = self.search(base='', scope=ldb.SCOPE_BASE, attrs=['dNSHostName'])
        return str(res[0]['dNSHostName'][0])

    def domain_dns_name(self):
        """return the DNS name of the domain root"""
        domain_dn = self.get_default_basedn()
        return domain_dn.canonical_str().split('/')[0]

    def domain_netbios_name(self):
        """return the NetBIOS name of the domain root"""
        domain_dn = self.get_default_basedn()
        dns_name = self.domain_dns_name()
        filter = "(&(objectClass=crossRef)(nETBIOSName=*)(ncName=%s)(dnsroot=%s))" % (domain_dn, dns_name)
        partitions_dn = self.get_partitions_dn()
        res = self.search(partitions_dn,
                          scope=ldb.SCOPE_ONELEVEL,
                          expression=filter)
        try:
            netbios_domain = res[0]["nETBIOSName"][0].decode()
        except IndexError:
            return None
        return netbios_domain

    def forest_dns_name(self):
        """return the DNS name of the forest root"""
        forest_dn = self.get_root_basedn()
        return forest_dn.canonical_str().split('/')[0]

    def load_partition_usn(self, base_dn):
        return dsdb._dsdb_load_partition_usn(self, base_dn)

    def set_schema(self, schema, write_indices_and_attributes=True):
        self.set_schema_from_ldb(schema.ldb, write_indices_and_attributes=write_indices_and_attributes)

    def set_schema_from_ldb(self, ldb_conn, write_indices_and_attributes=True):
        dsdb._dsdb_set_schema_from_ldb(self, ldb_conn, write_indices_and_attributes)

    def set_schema_update_now(self):
        ldif = """
dn:
changetype: modify
add: schemaUpdateNow
schemaUpdateNow: 1
"""
        self.modify_ldif(ldif)

    def dsdb_DsReplicaAttribute(self, ldb, ldap_display_name, ldif_elements):
        '''convert a list of attribute values to a DRSUAPI DsReplicaAttribute'''
        return dsdb._dsdb_DsReplicaAttribute(ldb, ldap_display_name, ldif_elements)

    def dsdb_normalise_attributes(self, ldb, ldap_display_name, ldif_elements):
        '''normalise a list of attribute values'''
        return dsdb._dsdb_normalise_attributes(ldb, ldap_display_name, ldif_elements)

    def get_attribute_from_attid(self, attid):
        """ Get from an attid the associated attribute

        :param attid: The attribute id for searched attribute
        :return: The name of the attribute associated with this id
        """
        if len(self.hash_oid_name.keys()) == 0:
            self._populate_oid_attid()
        if self.get_oid_from_attid(attid) in self.hash_oid_name:
            return self.hash_oid_name[self.get_oid_from_attid(attid)]
        else:
            return None

    def _populate_oid_attid(self):
        """Populate the hash hash_oid_name.

        This hash contains the oid of the attribute as a key and
        its display name as a value
        """
        self.hash_oid_name = {}
        res = self.search(expression="objectClass=attributeSchema",
                          controls=["search_options:1:2"],
                          attrs=["attributeID",
                                 "lDAPDisplayName"])
        if len(res) > 0:
            for e in res:
                strDisplay = str(e.get("lDAPDisplayName"))
                self.hash_oid_name[str(e.get("attributeID"))] = strDisplay

    def get_attribute_replmetadata_version(self, dn, att):
        """Get the version field trom the replPropertyMetaData for
        the given field

        :param dn: The on which we want to get the version
        :param att: The name of the attribute
        :return: The value of the version field in the replPropertyMetaData
            for the given attribute. None if the attribute is not replicated
        """

        res = self.search(expression="distinguishedName=%s" % dn,
                          scope=ldb.SCOPE_SUBTREE,
                          controls=["search_options:1:2"],
                          attrs=["replPropertyMetaData"])
        if len(res) == 0:
            return None

        repl = ndr_unpack(drsblobs.replPropertyMetaDataBlob,
                          res[0]["replPropertyMetaData"][0])
        ctr = repl.ctr
        if len(self.hash_oid_name.keys()) == 0:
            self._populate_oid_attid()
        for o in ctr.array:
            # Search for Description
            att_oid = self.get_oid_from_attid(o.attid)
            if att_oid in self.hash_oid_name and\
               att.lower() == self.hash_oid_name[att_oid].lower():
                return o.version
        return None

    def set_attribute_replmetadata_version(self, dn, att, value,
                                           addifnotexist=False):
        res = self.search(expression="distinguishedName=%s" % dn,
                          scope=ldb.SCOPE_SUBTREE,
                          controls=["search_options:1:2"],
                          attrs=["replPropertyMetaData"])
        if len(res) == 0:
            return None

        repl = ndr_unpack(drsblobs.replPropertyMetaDataBlob,
                          res[0]["replPropertyMetaData"][0])
        ctr = repl.ctr
        now = samba.unix2nttime(int(time.time()))
        found = False
        if len(self.hash_oid_name.keys()) == 0:
            self._populate_oid_attid()
        for o in ctr.array:
            # Search for Description
            att_oid = self.get_oid_from_attid(o.attid)
            if att_oid in self.hash_oid_name and\
               att.lower() == self.hash_oid_name[att_oid].lower():
                found = True
                seq = self.sequence_number(ldb.SEQ_NEXT)
                o.version = value
                o.originating_change_time = now
                o.originating_invocation_id = misc.GUID(self.get_invocation_id())
                o.originating_usn = seq
                o.local_usn = seq

        if not found and addifnotexist and len(ctr.array) > 0:
            o2 = drsblobs.replPropertyMetaData1()
            o2.attid = 589914
            att_oid = self.get_oid_from_attid(o2.attid)
            seq = self.sequence_number(ldb.SEQ_NEXT)
            o2.version = value
            o2.originating_change_time = now
            o2.originating_invocation_id = misc.GUID(self.get_invocation_id())
            o2.originating_usn = seq
            o2.local_usn = seq
            found = True
            tab = ctr.array
            tab.append(o2)
            ctr.count = ctr.count + 1
            ctr.array = tab

        if found:
            replBlob = ndr_pack(repl)
            msg = ldb.Message()
            msg.dn = res[0].dn
            msg["replPropertyMetaData"] = \
                ldb.MessageElement(replBlob,
                                   ldb.FLAG_MOD_REPLACE,
                                   "replPropertyMetaData")
            self.modify(msg, ["local_oid:1.3.6.1.4.1.7165.4.3.14:0"])

    def write_prefixes_from_schema(self):
        dsdb._dsdb_write_prefixes_from_schema_to_ldb(self)

    def get_partitions_dn(self):
        return dsdb._dsdb_get_partitions_dn(self)

    def get_nc_root(self, dn):
        return dsdb._dsdb_get_nc_root(self, dn)

    def get_wellknown_dn(self, nc_root, wkguid):
        h_nc = self.hash_well_known.get(str(nc_root))
        dn = None
        if h_nc is not None:
            dn = h_nc.get(wkguid)
        if dn is None:
            dn = dsdb._dsdb_get_wellknown_dn(self, nc_root, wkguid)
            if dn is None:
                return dn
            if h_nc is None:
                self.hash_well_known[str(nc_root)] = {}
                h_nc = self.hash_well_known[str(nc_root)]
            h_nc[wkguid] = dn
        return dn

    def set_minPwdAge(self, value):
        if not isinstance(value, bytes):
            value = str(value).encode('utf8')
        m = ldb.Message()
        m.dn = ldb.Dn(self, self.domain_dn())
        m["minPwdAge"] = ldb.MessageElement(value, ldb.FLAG_MOD_REPLACE, "minPwdAge")
        self.modify(m)

    def get_minPwdAge(self):
        res = self.search(self.domain_dn(), scope=ldb.SCOPE_BASE, attrs=["minPwdAge"])
        if len(res) == 0:
            return None
        elif "minPwdAge" not in res[0]:
            return None
        else:
            return int(res[0]["minPwdAge"][0])

    def set_maxPwdAge(self, value):
        if not isinstance(value, bytes):
            value = str(value).encode('utf8')
        m = ldb.Message()
        m.dn = ldb.Dn(self, self.domain_dn())
        m["maxPwdAge"] = ldb.MessageElement(value, ldb.FLAG_MOD_REPLACE, "maxPwdAge")
        self.modify(m)

    def get_maxPwdAge(self):
        res = self.search(self.domain_dn(), scope=ldb.SCOPE_BASE, attrs=["maxPwdAge"])
        if len(res) == 0:
            return None
        elif "maxPwdAge" not in res[0]:
            return None
        else:
            return int(res[0]["maxPwdAge"][0])

    def set_minPwdLength(self, value):
        if not isinstance(value, bytes):
            value = str(value).encode('utf8')
        m = ldb.Message()
        m.dn = ldb.Dn(self, self.domain_dn())
        m["minPwdLength"] = ldb.MessageElement(value, ldb.FLAG_MOD_REPLACE, "minPwdLength")
        self.modify(m)

    def get_minPwdLength(self):
        res = self.search(self.domain_dn(), scope=ldb.SCOPE_BASE, attrs=["minPwdLength"])
        if len(res) == 0:
            return None
        elif "minPwdLength" not in res[0]:
            return None
        else:
            return int(res[0]["minPwdLength"][0])

    def set_pwdProperties(self, value):
        if not isinstance(value, bytes):
            value = str(value).encode('utf8')
        m = ldb.Message()
        m.dn = ldb.Dn(self, self.domain_dn())
        m["pwdProperties"] = ldb.MessageElement(value, ldb.FLAG_MOD_REPLACE, "pwdProperties")
        self.modify(m)

    def get_pwdProperties(self):
        res = self.search(self.domain_dn(), scope=ldb.SCOPE_BASE, attrs=["pwdProperties"])
        if len(res) == 0:
            return None
        elif "pwdProperties" not in res[0]:
            return None
        else:
            return int(res[0]["pwdProperties"][0])

    def set_dsheuristics(self, dsheuristics):
        m = ldb.Message()
        m.dn = ldb.Dn(self, "CN=Directory Service,CN=Windows NT,CN=Services,%s"
                      % self.get_config_basedn().get_linearized())
        if dsheuristics is not None:
            m["dSHeuristics"] = \
                ldb.MessageElement(dsheuristics,
                                   ldb.FLAG_MOD_REPLACE,
                                   "dSHeuristics")
        else:
            m["dSHeuristics"] = \
                ldb.MessageElement([], ldb.FLAG_MOD_DELETE,
                                   "dSHeuristics")
        self.modify(m)

    def get_dsheuristics(self):
        res = self.search("CN=Directory Service,CN=Windows NT,CN=Services,%s"
                          % self.get_config_basedn().get_linearized(),
                          scope=ldb.SCOPE_BASE, attrs=["dSHeuristics"])
        if len(res) == 0:
            dsheuristics = None
        elif "dSHeuristics" in res[0]:
            dsheuristics = res[0]["dSHeuristics"][0]
        else:
            dsheuristics = None

        return dsheuristics

    def create_ou(self, ou_dn, description=None, name=None, sd=None):
        """Creates an organizationalUnit object
        :param ou_dn: dn of the new object
        :param description: description attribute
        :param name: name atttribute
        :param sd: security descriptor of the object, can be
        an SDDL string or security.descriptor type
        """
        m = {"dn": ou_dn,
             "objectClass": "organizationalUnit"}

        if description:
            m["description"] = description
        if name:
            m["name"] = name

        if sd:
            m["nTSecurityDescriptor"] = ndr_pack(sd)
        self.add(m)

    def sequence_number(self, seq_type):
        """Returns the value of the sequence number according to the requested type
        :param seq_type: type of sequence number
         """
        self.transaction_start()
        try:
            seq = super(SamDB, self).sequence_number(seq_type)
        except:
            self.transaction_cancel()
            raise
        else:
            self.transaction_commit()
        return seq

    def get_dsServiceName(self):
        '''get the NTDS DN from the rootDSE'''
        res = self.search(base="", scope=ldb.SCOPE_BASE, attrs=["dsServiceName"])
        return str(res[0]["dsServiceName"][0])

    def get_serverName(self):
        '''get the server DN from the rootDSE'''
        res = self.search(base="", scope=ldb.SCOPE_BASE, attrs=["serverName"])
        return str(res[0]["serverName"][0])

    def dns_lookup(self, dns_name, dns_partition=None):
        '''Do a DNS lookup in the database, returns the NDR database structures'''
        if dns_partition is None:
            return dsdb_dns.lookup(self, dns_name)
        else:
            return dsdb_dns.lookup(self, dns_name,
                                   dns_partition=dns_partition)

    def dns_extract(self, el):
        '''Return the NDR database structures from a dnsRecord element'''
        return dsdb_dns.extract(self, el)

    def dns_replace(self, dns_name, new_records):
        '''Do a DNS modification on the database, sets the NDR database
        structures on a DNS name
        '''
        return dsdb_dns.replace(self, dns_name, new_records)

    def dns_replace_by_dn(self, dn, new_records):
        '''Do a DNS modification on the database, sets the NDR database
        structures on a LDB DN

        This routine is important because if the last record on the DN
        is removed, this routine will put a tombstone in the record.
        '''
        return dsdb_dns.replace_by_dn(self, dn, new_records)

    def garbage_collect_tombstones(self, dn, current_time,
                                   tombstone_lifetime=None):
        '''garbage_collect_tombstones(lp, samdb, [dn], current_time, tombstone_lifetime)
        -> (num_objects_expunged, num_links_expunged)'''

        if not is_ad_dc_built():
            raise SamDBError('Cannot garbage collect tombstones: ' \
                'AD DC was not built')

        if tombstone_lifetime is None:
            return dsdb._dsdb_garbage_collect_tombstones(self, dn,
                                                         current_time)
        else:
            return dsdb._dsdb_garbage_collect_tombstones(self, dn,
                                                         current_time,
                                                         tombstone_lifetime)

    def create_own_rid_set(self):
        '''create a RID set for this DSA'''
        return dsdb._dsdb_create_own_rid_set(self)

    def allocate_rid(self):
        '''return a new RID from the RID Pool on this DSA'''
        return dsdb._dsdb_allocate_rid(self)

    def normalize_dn_in_domain(self, dn):
        '''return a new DN expanded by adding the domain DN

        If the dn is already a child of the domain DN, just
        return it as-is.

        :param dn: relative dn
        '''
        domain_dn = ldb.Dn(self, self.domain_dn())

        if isinstance(dn, ldb.Dn):
            dn = str(dn)

        full_dn = ldb.Dn(self, dn)
        if not full_dn.is_child_of(domain_dn):
            full_dn.add_base(domain_dn)
        return full_dn

class dsdb_Dn(object):
    '''a class for binary DN'''

    def __init__(self, samdb, dnstring, syntax_oid=None):
        '''create a dsdb_Dn'''
        if syntax_oid is None:
            # auto-detect based on string
            if dnstring.startswith("B:"):
                syntax_oid = dsdb.DSDB_SYNTAX_BINARY_DN
            elif dnstring.startswith("S:"):
                syntax_oid = dsdb.DSDB_SYNTAX_STRING_DN
            else:
                syntax_oid = dsdb.DSDB_SYNTAX_OR_NAME
        if syntax_oid in [dsdb.DSDB_SYNTAX_BINARY_DN, dsdb.DSDB_SYNTAX_STRING_DN]:
            # it is a binary DN
            colons = dnstring.split(':')
            if len(colons) < 4:
                raise RuntimeError("Invalid DN %s" % dnstring)
            prefix_len = 4 + len(colons[1]) + int(colons[1])
            self.prefix = dnstring[0:prefix_len]
            self.binary = self.prefix[3 + len(colons[1]):-1]
            self.dnstring = dnstring[prefix_len:]
        else:
            self.dnstring = dnstring
            self.prefix = ''
            self.binary = ''
        self.dn = ldb.Dn(samdb, self.dnstring)

    def __str__(self):
        return self.prefix + str(self.dn.extended_str(mode=1))

    def __cmp__(self, other):
        ''' compare dsdb_Dn values similar to parsed_dn_compare()'''
        dn1 = self
        dn2 = other
        guid1 = dn1.dn.get_extended_component("GUID")
        guid2 = dn2.dn.get_extended_component("GUID")

        v = cmp(guid1, guid2)
        if v != 0:
            return v
        v = cmp(dn1.binary, dn2.binary)
        return v

    # In Python3, __cmp__ is replaced by these 6 methods
    def __eq__(self, other):
        return self.__cmp__(other) == 0

    def __ne__(self, other):
        return self.__cmp__(other) != 0

    def __lt__(self, other):
        return self.__cmp__(other) < 0

    def __le__(self, other):
        return self.__cmp__(other) <= 0

    def __gt__(self, other):
        return self.__cmp__(other) > 0

    def __ge__(self, other):
        return self.__cmp__(other) >= 0

    def get_binary_integer(self):
        '''return binary part of a dsdb_Dn as an integer, or None'''
        if self.prefix == '':
            return None
        return int(self.binary, 16)

    def get_bytes(self):
        '''return binary as a byte string'''
        return binascii.unhexlify(self.binary)