ldap - OpenLDAP Lightweight Directory Access Protocol API

OpenLDAP LDAP (libldap, -lldap)

#include <ldap.h>

The Lightweight Directory Access Protocol provides access to X.500 directory services. The services may be stand-alone or part of a distributed directory service. This API supports LDAP over TCP (RFC2251), LDAP over SSL, and LDAP over IPC (UNIX domain sockets). This API supports SASL (RFC2829) and Start TLS (RFC2830). This API is based upon IETF C LDAP API draft specification, a 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 routines. These routines are found in the -lldap library.

The basic interaction is as follows. A session handle is created using ldap_init(3) or ldap_initialize(3). (The ldap_initialize(3) routine is preferred, but is not part of the draft specification.) The underlying session is established upon first use which is commonly an LDAP bind operation. The LDAP bind operation is performed by calling ldap_sasl_bind(3) or one of its friends. Next, other operations 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 calling ldap_unbind_ext(3). Errors can be interpreted by calling ldap_err2string(3).

Search filters to be passed to the ldap search routines are to be constructed by hand and should conform to RFC 2254.

Results obtained from the ldap 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.

This library supports both LDAP Version 2 and Version 3, with the Version 2 protocol selected by default. LDAP Version 3 operations can be extended through the use of controls. Controls can be sent to a server or returned to the client with any LDAP message. Extended versions of the standard routines are available for use with controls. These routines are generally named by adding _ext to the regular routine's name.

The ldap_url(3) routines can be used to test a URL to see if it is an LDAP URL, to parse LDAP URLs into their component pieces, and to initiate searches directly using an LDAP URL.

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.

Also included in the distribution is a set of lightweight Basic Encoding Rules routines. These routines are used by the LDAP library routines to encode and decode LDAP protocol elements using the (slightly simplified) Basic Encoding Rules defined by LDAP. They are not normally used directly by an LDAP application program except in the handling 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-memory(3), and lber-types(3).

ldap_open(3)

open a connection to an LDAP server (deprecated, use ldap_init(3))

ldap_init(3)

initialize the LDAP library without opening a connection to a server

ldap_initialize(3)

initialize the LDAP library without opening a connection to a server

ldap_result(3)

wait for the result from an asynchronous operation

ldap_abandon(3)

abandon (abort) an asynchronous operation

ldap_add(3)

asynchronously add an entry

ldap_add_s(3)

synchronously add an entry

ldap_bind(3)

asynchronously bind to the directory

ldap_bind_s(3)

synchronously bind to the directory

ldap_simple_bind(3)

asynchronously bind to the directory using simple authentication

ldap_simple_bind_s(3)

synchronously bind to the directory using simple authentication

ldap_unbind(3)

synchronously unbind from the LDAP server and close the connection

ldap_unbind_s(3)

equivalent to ldap_unbind(3)

ldap_memfree (3)

dispose of memory allocated by LDAP routines.

ldap_compare(3)

asynchronously compare to a directory entry

ldap_compare_s(3)

synchronously compare to a directory entry

ldap_delete(3)

asynchronously delete an entry

ldap_delete_s(3)

synchronously delete an entry

ldap_perror(3)

print an LDAP error indication to standard error

ld_errno(3)

LDAP error indication

ldap_result2error(3)

extract LDAP error indication from LDAP result

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

ldap_explode_rdn(3)

convert an RDN into its component parts

ldap_get_values(3)

return an attribute's values

ldap_get_values_len(3)

return an attribute's values with lengths

ldap_value_free(3)

free memory allocated by ldap_get_values(3)

ldap_value_free_len(3)

free memory allocated by ldap_get_values_len(3)

ldap_count_values(3)

return number of values

ldap_count_values_len(3)

return number of values

ldap_modify(3)

asynchronously modify an entry

ldap_modify_s(3)

synchronously modify an entry

ldap_mods_free(3)

free array of pointers to mod structures used by ldap_modify(3)

ldap_modrdn2(3)

asynchronously modify the RDN of an entry

ldap_modrdn2_s(3)

synchronously modify the RDN of an entry

ldap_modrdn(3)

deprecated - use ldap_modrdn2(3)

ldap_modrdn_s(3)

depreciated - use ldap_modrdn2_s(3)

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(3)

asynchronously search the directory

ldap_search_s(3)

synchronously search the directory

ldap_search_st(3)

synchronously search the directory with timeout

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

ldap.conf(5), slapd(8), draft-ietf-ldapext-ldap-c-api-xx.txt <http://www.ietf.org>

is developed and maintained by The OpenLDAP Project (http://www.openldap.org/). is derived from University of Michigan LDAP 3.3 Release.

These API manual pages are based upon descriptions provided in the IETF C LDAP API Internet Draft, a work in progress, edited by Mark Smith.