ldap - OpenLDAP Lightweight Directory Access Protocol API
OpenLDAP LDAP (libldap, -lldap)
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 sup-
ports 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 proto-
col. 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
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 com-
monly 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 con-
trols. 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 rou-
tines are generally named by adding _ext to the regular routine's name.
UNIFORM RESOURCE LOCATORS (URLS)
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
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 con-
trols 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
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
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
return first attribute name in an entry
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
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
return an attribute's values with lengths
ldap_value_free(3) free memory allocated by ldap_get_values(3)
free memory allocated by ldap_get_values_len(3)
return number of values
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
sort a list of search results
ldap_sort_values(3) sort a list of attribute values
case insensitive string comparison
ldap.conf(5), slapd(8), draft-ietf-ldapext-ldap-c-api-xx.txt <http://www.ietf.org>
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 based upon descriptions provided in the IETF C LDAP API Inter-
net Draft, a work in progress, edited by Mark Smith.
OpenLDAP 2.1.X RELEASEDATE LDAP(3)