# SPDX-FileCopyrightText: 2004-2025 Univention GmbH
# SPDX-License-Identifier: AGPL-3.0-only
"""|LDAP| locking methods for |UDM|."""
import time
import ldap
import univention.admin.uexceptions
from univention.admin import localization
translation = localization.translation('univention/admin')
_ = translation.translate
[docs]
def lockDn(lo, position, type, value, scope):
"""
Build |DN| of lock object.
:param lo: |LDAP| connection.
:param position: |UDM| position specifying the |LDAP| base container.
:param type: A string describing the type of object, e.g. `user`.
:param value: A unique value for the object, e.g. `uid`.
:param scope: The scope for the lock, e.g. `domain`.
:returns: A |LDAP| |DN|.
"""
dn = [
[('cn', value, ldap.AVA_STRING)],
[('cn', type, ldap.AVA_STRING)],
[('cn', 'temporary', ldap.AVA_STRING)],
[('cn', 'univention', ldap.AVA_STRING)],
]
if scope == 'domain':
dn += ldap.dn.str2dn(position.getDomain())
else:
dn += ldap.dn.str2dn(position.getBase())
return ldap.dn.dn2str(dn)
[docs]
def lock(lo, position, type, value, scope='domain', timeout=300):
"""
Lock an |UDM| object.
:param lo: |LDAP| connection.
:param position: |UDM| position specifying the |LDAP| base container.
:param type: A string describing the type of object, e.g. `user`.
:param value: A unique value for the object, e.g. `uid`.
:param scope: The scope for the lock, e.g. `domain`.
:param timeout: Number of seconds for the lock being valid.
:raises univention.admin.uexceptions.permissionDenied: if the lock time cannot be modified.
:raises univention.admin.uexceptions.noLock: if the lock cannot be acquired.
:returns: Number of seconds since the UNIX epoch until which the lock is acquired.
"""
dn = lockDn(lo, position, type, value.decode('utf-8'), scope)
now = int(time.time())
locktime = now + timeout if timeout > 0 else 0
al = [
('objectClass', [b'top', b'lock']),
('cn', [value]),
('lockTime', [str(locktime).encode('ascii')]),
]
if not lo.authz_connection.get(dn, ['lockTime']):
try:
lo.authz_connection.add(dn, al)
return locktime
except ldap.ALREADY_EXISTS:
pass
except univention.admin.uexceptions.permissionDenied:
raise univention.admin.uexceptions.permissionDenied(_('Can not modify lock time of %r.') % (dn,))
oldlocktime = lo.authz_connection.getAttr(dn, 'lockTime')
oldlocktime = int(oldlocktime[0]) if oldlocktime and oldlocktime[0] else 0
# lock is old, try again
if oldlocktime > 0 and oldlocktime < now:
ml = [
('lockTime', str(oldlocktime).encode('ascii'), str(locktime).encode('ascii')),
]
try:
lo.authz_connection.modify(dn, ml, exceptions=True)
return locktime
except ldap.INSUFFICIENT_ACCESS:
raise univention.admin.uexceptions.permissionDenied(_('Can not modify lock time of %r.') % (dn,))
raise univention.admin.uexceptions.noLock(_('The attribute %r could not get locked. Another process is already trying to acquire the value.') % (type,))
[docs]
def relock(lo, position, type, value, scope='domain', timeout=300):
"""
Extend a lock of an |UDM| object.
:param lo: |LDAP| connection.
:param position: |UDM| position specifying the |LDAP| base container.
:param type: A string describing the type of object, e.g. `user`.
:param value: A unique value for the object, e.g. `uid`.
:param scope: The scope for the lock, e.g. `domain`.
:param timeout: Number of seconds for the lock being valid.
:raises univention.admin.uexceptions.permissionDenied: if the lock time cannot be modified.
:raises univention.admin.uexceptions.noLock: if the lock was not acquired.
:returns: Number of seconds since the UNIX epoch until which the lock is acquired.
"""
dn = lockDn(lo, position, type, value.decode('utf-8'), scope)
now = int(time.time())
locktime = now + timeout if timeout > 0 else 0
ml = [
('lockTime', b'1', str(locktime).encode('ASCII')),
]
try:
lo.authz_connection.modify(dn, ml, exceptions=True)
return locktime
except ldap.INSUFFICIENT_ACCESS:
raise univention.admin.uexceptions.permissionDenied(_('Can not modify lock time of %r.') % (dn,))
# locking failed
raise univention.admin.uexceptions.noLock(_('The attribute %r could not get locked.') % (type,))
[docs]
def unlock(lo, position, type, value, scope='domain'):
"""
Unlock an |UDM| object.
:param lo: |LDAP| connection.
:param position: |UDM| position specifying the |LDAP| base container.
:param type: A string describing the type of object, e.g. `user`.
:param value: A unique value for the object, e.g. `uid`.
:param scope: The scope for the lock, e.g. `domain`.
"""
dn = lockDn(lo, position, type, value.decode('utf-8'), scope)
try:
lo.authz_connection.delete(dn, exceptions=True)
except ldap.NO_SUCH_OBJECT:
pass
[docs]
def getLock(lo, position, type, value, scope='domain'):
"""
Check if an |UDM| object is locked.
:param lo: |LDAP| connection.
:param position: |UDM| position specifying the |LDAP| base container.
:param type: A string describing the type of object, e.g. `user`.
:param value: A unique value for the object, e.g. `uid`.
:param scope: The scope for the lock, e.g. `domain`.
:returns: Number of seconds since the UNIX epoch until which the lock is acquired or `0`.
"""
dn = lockDn(lo, position, type, value.decode('utf-8'), scope)
try:
return int(lo.authz_connection.getAttr(dn, 'lockTime', exceptions=True)[0])
except ldap.NO_SUCH_OBJECT:
return 0
