ldap
LDAP(3) LDAP(3)
NAME
ldap - OpenLDAP Lightweight Directory Access Protocol API
LIBRARY
OpenLDAP LDAP (libldap, -lldap)
SYNOPSIS
#include <ldap.h>
DESCRIPTION
The Lightweight Directory Access Protocol (LDAP) (RFC 3377) provides
access to X.500 directory services. These services may be stand-alone
or part of a distributed directory service. This client API supports
LDAP over TCP (RFC2251), LDAP over TLS/SSL, and LDAP over IPC (UNIX
domain sockets). This API supports SASL (RFC2829) and Start TLS
(RFC2830) as well as a number of protocol extensions. This API is
loosely based upon IETF/LDAPEXT C LDAP API draft specification, a
(orphaned) work in progress.
The OpenLDAP Software package includes a stand-alone server in
slapd(8), various LDAP clients, and an LDAP client library used to
provide programmatic access to the LDAP protocol. This man page gives
an overview of the LDAP library routines.
Both synchronous and asynchronous APIs are provided. Also included
are various routines to parse the results returned from these rou-
tines. These routines are found in the -lldap library.
The basic interaction is as follows. A session handle is created
using ldap_initialize(3) and set the protocol version to 3 by calling
ldap_set_option(3). The underlying session is established first oper-
ation is issued. This would generally be a Start TLS or Bind opera-
tion. A Start TLS operation is performed by calling
ldap_start_tls_s(3). A LDAP bind operation is performed by calling
ldap_sasl_bind(3) or one of its friends. Subsequently, other opera-
tions are performed by calling one of the synchronous or asynchronous
routines (e.g., ldap_search_ext_s(3) or ldap_search_ext(3) followed by
ldap_result(3)). Results returned from these routines are interpreted
by calling the LDAP parsing routines such as ldap_parse_result(3).
The LDAP association and underlying connection is terminated by call-
ing ldap_unbind_ext(3). Errors can be interpreted by calling
ldap_err2string(3).
LDAP versions
This library supports version 3 of the Lightweight Directory Access
Protocol (LDAPv3) as defined in RFC 3377. It also supports a varient
of version 2 of LDAP as defined by U-Mich LDAP and, to some degree,
RFC 1777. Version 2 (all varients) should be viewed as obsolete.
Version 3 should be used instead.
For backwards compatibility reasons, the library defaults to version
2. Hence, all new applications (and all actively maintained applica-
tions) should use ldap_set_option(3) to select version 3. The library
manual pages assume version 3 has been selected.
INPUT and OUTPUT PARAMETERS
All character string input/output is expected to be/is UTF-8 encoded
Unicode (version 3.2).
Distinguished names (DN) (and relative distinguished names (RDN) to be
passed to the LDAP routines should conform to RFC 2253. The
ldap_explode_dn(3) routines can be used to work with DNs.
Search filters to be passed to the search routines are to be con-
structed by hand and should conform to RFC 2254.
LDAP URL are to be passed to routines are expected to conform to RFC
2255. The ldap_url(3) routines can be used to work with LDAP URLs.
DISPLAYING RESULTS
Results obtained from the search routines can be output by hand, by
calling ldap_first_entry(3) and ldap_next_entry(3) to step through the
entries returned, ldap_first_attribute(3) and ldap_next_attribute(3)
to step through an entry’s attributes, and ldap_get_values(3) to
retrieve a given attribute’s values. Attribute values may or may not
be displayable.
UTILITY ROUTINES
Also provided are various utility routines. The ldap_sort(3) routines
are used to sort the entries and values returned via the ldap search
routines.
BER LIBRARY
Also included in the distribution is a set of lightweight Basic Encod-
ing Rules routines. These routines are used by the LDAP library rou-
tines to encode and decode LDAP protocol elements using the (slightly
simplified) Basic Encoding Rules defined by LDAP. They are not nor-
mally used directly by an LDAP application program except in the han-
dling of controls and extended operations. The routines provide a
printf and scanf-like interface, as well as lower-level access. These
routines are discussed in lber-decode(3), lber-encode(3), lber-mem-
ory(3), and lber-types(3).
INDEX
ldap_initialize(3) initialize the LDAP library without opening a con-
nection to a server
ldap_result(3) wait for the result from an asynchronous operation
ldap_abandon_ext(3) abandon (abort) an asynchronous operation
ldap_add_ext(3) asynchronously add an entry
ldap_add_ext_s(3) synchronously add an entry
ldap_sasl_bind(3) asynchronously bind to the directory
ldap_sasl_bind_s(3) synchronously bind to the directory
ldap_unbind_ext(3) synchronously unbind from the LDAP server and
close the connection
ldap_unbind_ext_s(3)
equivalent to ldap_unbind_ext(3)
ldap_memfree(3) dispose of memory allocated by LDAP routines.
ldap_compare_ext(3) asynchronously compare to a directory entry
ldap_compare_ext_s(3)
synchronously compare to a directory entry
ldap_delete_ext(3) asynchronously delete an entry
ldap_delete_ext_s(3)
synchronously delete an entry
ld_errno(3) LDAP error indication
ldap_errlist(3) list of LDAP errors and their meanings
ldap_err2string(3) convert LDAP error indication to a string
ldap_first_attribute(3)
return first attribute name in an entry
ldap_next_attribute(3)
return next attribute name in an entry
ldap_first_entry(3) return first entry in a chain of search results
ldap_next_entry(3) return next entry in a chain of search results
ldap_count_entries(3)
return number of entries in a search result
ldap_get_dn(3) extract the DN from an entry
ldap_explode_dn(3) convert a DN into its component parts (deprecated)
ldap_explode_rdn(3) convert an RDN into its component parts (depre-
cated)
ldap_get_values_len(3)
return an attribute’s values with lengths
ldap_value_free_len(3)
free memory allocated by ldap_get_values_len(3)
ldap_count_values_len(3)
return number of values
ldap_modify_ext(3) asynchronously modify an entry
ldap_modify_ext_s(3)
synchronously modify an entry
ldap_mods_free(3) free array of pointers to mod structures used by
ldap_modify_ext(3)
ldap_rename(3) asynchronously rename an entry
ldap_rename_s(3) synchronously rename an entry
ldap_msgfree(3) free results allocated by ldap_result(3)
ldap_msgtype(3) return the message type of a message from
ldap_result(3)
ldap_msgid(3) return the message id of a message from
ldap_result(3)
ldap_search_ext(3) asynchronously search the directory
ldap_search_ext_s(3)
synchronously search the directory
ldap_is_ldap_url(3) check a URL string to see if it is an LDAP URL
ldap_url_parse(3) break up an LDAP URL string into its components
ldap_sort_entries(3)
sort a list of search results
ldap_sort_values(3) sort a list of attribute values
ldap_sort_strcasecmp(3)
case insensitive string comparison
SEE ALSO
ldap.conf(5), slapd(8), draft-ietf-ldapext-ldap-c-api-
xx.txt <http://www.ietf.org>
ACKNOWLEDGEMENTS
OpenLDAP is developed and maintained by The OpenLDAP Project
(http://www.openldap.org/). OpenLDAP is derived from University of
Michigan LDAP 3.3 Release.
These API manual pages are loosely based upon descriptions provided in
the IETF/LDAPEXT C LDAP API Internet Draft, a (orphaned) work in
progress.
OpenLDAP 2.2.13 2004/06/10 LDAP(3)
