Provided by: libldap2-dev_2.4.49+dfsg-2ubuntu1.10_amd64 
NAME
ldap_sync_init, ldap_sync_init_refresh_only, ldap_sync_init_refresh_and_persist, ldap_sync_poll - LDAP
sync routines
LIBRARY
OpenLDAP LDAP (libldap, -lldap)
SYNOPSIS
#include <ldap.h>
int ldap_sync_init(ldap_sync_t *ls, int mode);
int ldap_sync_init_refresh_only(ldap_sync_t *ls);
int ldap_sync_init_refresh_and_persist(ldap_sync_t *ls);
int ldap_sync_poll(ldap_sync_t *ls);
ldap_sync_t * ldap_sync_initialize(ldap_sync_t *ls);
void ldap_sync_destroy(ldap_sync_t *ls, int freeit);
typedef int (*ldap_sync_search_entry_f)(ldap_sync_t *ls,
LDAPMessage *msg, struct berval *entryUUID,
ldap_sync_refresh_t phase);
typedef int (*ldap_sync_search_reference_f)(ldap_sync_t *ls,
LDAPMessage *msg);
typedef int (*ldap_sync_intermediate_f)(ldap_sync_t *ls,
LDAPMessage *msg, BerVarray syncUUIDs,
ldap_sync_refresh_t phase);
typedef int (*ldap_sync_search_result_f)(ldap_sync_t *ls,
LDAPMessage *msg, int refreshDeletes);
DESCRIPTION
These routines provide an interface to the LDAP Content Synchronization operation (RFC 4533). They
require an ldap_sync_t structure to be set up with parameters required for various phases of the
operation; this includes setting some handlers for special events. All handlers take a pointer to the
ldap_sync_t structure as the first argument, and a pointer to the LDAPMessage structure as received from
the server by the client library, plus, occasionally, other specific arguments.
The members of the ldap_sync_t structure are:
char *ls_base
The search base; by default, the BASE option in ldap.conf(5).
int ls_scope
The search scope (one of LDAP_SCOPE_BASE, LDAP_SCOPE_ONELEVEL, LDAP_SCOPE_SUBORDINATE or
LDAP_SCOPE_SUBTREE; see ldap.h for details).
char *ls_filter
The filter (RFC 4515); by default, (objectClass=*).
char **ls_attrs
The requested attributes; by default NULL, indicating all user attributes.
int ls_timelimit
The requested time limit (in seconds); by default 0, to indicate no limit.
int ls_sizelimit
The requested size limit (in entries); by default 0, to indicate no limit.
int ls_timeout
The desired timeout during polling with ldap_sync_poll(3). A value of -1 means that polling is
blocking, so ldap_sync_poll(3) will not return until a message is received; a value of 0 means
that polling returns immediately, no matter if any response is available or not; a positive value
represents the timeout the ldap_sync_poll(3) function will wait for response before returning,
unless a message is received; in that case, ldap_sync_poll(3) returns as soon as the message is
available.
ldap_sync_search_entry_f ls_search_entry
A function that is called whenever an entry is returned. The msg argument is the LDAPMessage that
contains the searchResultEntry; it can be parsed using the regular client API routines, like
ldap_get_dn(3), ldap_first_attribute(3), and so on. The entryUUID argument contains the entryUUID
of the entry. The phase argument indicates the type of operation: one of LDAP_SYNC_CAPI_PRESENT,
LDAP_SYNC_CAPI_ADD, LDAP_SYNC_CAPI_MODIFY, LDAP_SYNC_CAPI_DELETE; in case of
LDAP_SYNC_CAPI_PRESENT or LDAP_SYNC_CAPI_DELETE, only the DN is contained in the LDAPMessage; in
case of LDAP_SYNC_CAPI_MODIFY, the whole entry is contained in the LDAPMessage, and the
application is responsible of determining the differences between the new view of the entry
provided by the caller and the data already known.
ldap_sync_search_reference_f ls_search_reference
A function that is called whenever a search reference is returned. The msg argument is the
LDAPMessage that contains the searchResultReference; it can be parsed using the regular client API
routines, like ldap_parse_reference(3).
ldap_sync_intermediate_f ls_intermediate
A function that is called whenever something relevant occurs during the refresh phase of the
search, which is marked by an intermediateResponse message type. The msg argument is the
LDAPMessage that contains the intermediate response; it can be parsed using the regular client API
routines, like ldap_parse_intermediate(3). The syncUUIDs argument contains an array of UUIDs of
the entries that depends on the value of the phase argument. In case of LDAP_SYNC_CAPI_PRESENTS,
the "present" phase is being entered; this means that the following sequence of results will
consist in entries in "present" sync state. In case of LDAP_SYNC_CAPI_DELETES, the "deletes"
phase is being entered; this means that the following sequence of results will consist in entries
in "delete" sync state. In case of LDAP_SYNC_CAPI_PRESENTS_IDSET, the message contains a set of
UUIDs of entries that are present; it replaces a "presents" phase. In case of
LDAP_SYNC_CAPI_DELETES_IDSET, the message contains a set of UUIDs of entries that have been
deleted; it replaces a "deletes" phase. In case of LDAP_SYNC_CAPI_DONE, a "presents" phase with
"refreshDone" set to "TRUE" has been returned to indicate that the refresh phase of
refreshAndPersist is over, and the client should start polling. Except for the
LDAP_SYNC_CAPI_PRESENTS_IDSET and LDAP_SYNC_CAPI_DELETES_IDSET cases, syncUUIDs is NULL.
ldap_sync_search_result_f ls_search_result
A function that is called whenever a searchResultDone is returned. In refreshAndPersist this can
only occur when the server decides that the search must be interrupted. The msg argument is the
LDAPMessage that contains the response; it can be parsed using the regular client API routines,
like ldap_parse_result(3). The refreshDeletes argument is not relevant in this case; it should
always be -1.
void *ls_private
A pointer to private data. The client may register here a pointer to data the handlers above may
need.
LDAP *ls_ld
A pointer to a LDAP structure that is used to connect to the server. It is the responsibility of
the client to initialize the structure and to provide appropriate authentication and security in
place.
GENERAL USE
A ldap_sync_t structure is initialized by calling ldap_sync_initialize(3). This simply clears out the
contents of an already existing ldap_sync_t structure, and sets appropriate values for some members.
After that, the caller is responsible for setting up the connection (member ls_ld), eventually setting up
transport security (TLS), for binding and any other initialization. The caller must also fill all the
documented search-related fields of the ldap_sync_t structure.
At the end of a session, the structure can be cleaned up by calling ldap_sync_destroy(3), which takes
care of freeing all data assuming it was allocated by ldap_mem*(3) routines. Otherwise, the caller
should take care of destroying and zeroing out the documented search-related fields, and call
ldap_sync_destroy(3) to free undocumented members set by the API.
REFRESH ONLY
The refreshOnly functionality is obtained by periodically calling ldap_sync_init(3) with mode set to
LDAP_SYNC_REFRESH_ONLY, or, which is equivalent, by directly calling ldap_sync_init_refresh_only(3). The
state of the search, and the consistency of the search parameters, is preserved across calls by passing
the ldap_sync_t structure as left by the previous call.
REFRESH AND PERSIST
The refreshAndPersist functionality is obtained by calling ldap_sync_init(3) with mode set to
LDAP_SYNC_REFRESH_AND_PERSIST, or, which is equivalent, by directly calling
ldap_sync_init_refresh_and_persist(3) and, after a successful return, by repeatedly polling with
ldap_sync_poll(3) according to the desired pattern.
A client may insert a call to ldap_sync_poll(3) into an external loop to check if any modification was
returned; in this case, it might be appropriate to set ls_timeout to 0, or to set it to a finite, small
value. Otherwise, if the client's main purpose consists in waiting for responses, a timeout of -1 is
most suitable, so that the function only returns after some data has been received and handled.
ERRORS
All routines return any LDAP error resulting from a lower-level error in the API calls they are based on,
or LDAP_SUCCESS in case of success. ldap_sync_poll(3) may return LDAP_SYNC_REFRESH_REQUIRED if a full
refresh is requested by the server. In this case, it is appropriate to call ldap_sync_init(3) again,
passing the same ldap_sync_t structure as resulted from any previous call.
NOTES
SEE ALSO
ldap(3), ldap_search_ext(3), ldap_result(3); RFC 4533 (http://www.rfc-editor.org),
AUTHOR
Designed and implemented by Pierangelo Masarati, based on RFC 4533 and loosely inspired by syncrepl code
in slapd(8).
ACKNOWLEDGEMENTS
Initially developed by SysNet s.n.c. OpenLDAP is developed and maintained by The OpenLDAP Project
(http://www.openldap.org/). OpenLDAP is derived from University of Michigan LDAP 3.3 Release.
OpenLDAP 2020/01/30 LDAP_SYNC(3)