Ubuntu Manpage: ldap_init, ldap_initialize, ldap_open - Initialize the LDAP library and open a connection

Provided by: libldap-dev_2.5.18+dfsg-0ubuntu0.22.04.2_amd64

NAME

       ldap_init,  ldap_initialize, ldap_open - Initialize the LDAP library and open a connection
       to an LDAP server

LIBRARY

       OpenLDAP LDAP (libldap, -lldap)

SYNOPSIS

       #include <ldap.h>

       LDAP *ldap_open(host, port)
       char *host;
       int port;

       LDAP *ldap_init(host, port)
       char *host;
       int port;

       int ldap_initialize(ldp, uri)
       LDAP **ldp;
       char *uri;

       int ldap_connect(ldp)
       LDAP *ldp;

       int ldap_set_urllist_proc(ld, proc, params)
       LDAP *ld;
       LDAP_URLLIST_PROC *proc;
       void *params;

       int (LDAP_URLLIST_PROC)(ld, urllist, url, params);
       LDAP *ld;
       LDAPURLDesc **urllist;
       LDAPURLDesc **url;
       void *params;

       #include <openldap.h>

       int ldap_init_fd(fd, proto, uri, ldp)
       ber_socket_t fd;
       int proto;
       char *uri;
       LDAP **ldp;

DESCRIPTION

ldap_open() opens a connection to an LDAP server and allocates an LDAP structure which is
used to identify the connection and to maintain per-connection information. ldap_init()
allocates an LDAP structure but does not open an initial connection. ldap_initialize()
allocates an LDAP structure but does not open an initial connection. ldap_init_fd()
allocates an LDAP structure using an existing connection on the provided socket. One of
these routines must be called before any operations are attempted.

ldap_open() takes host, the hostname on which the LDAP server is running, and port, the
port number to which to connect. If the default IANA-assigned port of 389 is desired,
LDAP_PORT should be specified for port. The host parameter may contain a blank-separated
list of hosts to try to connect to, and each host may optionally by of the form host:port.
If present, the :port overrides the port parameter to ldap_open(). Upon successfully
making a connection to an LDAP server, ldap_open() returns a pointer to an opaque LDAP
structure, which should be passed to subsequent calls to ldap_bind(), ldap_search(), etc.
Certain fields in the LDAP structure can be set to indicate size limit, time limit, and
how aliases are handled during operations; read and write access to those fields must
occur by calling ldap_get_option(3) and ldap_set_option(3) respectively, whenever
possible.

ldap_init() acts just like ldap_open(), but does not open a connection to the LDAP server.
The actual connection open will occur when the first operation is attempted.

ldap_initialize() acts like ldap_init(), but it returns an integer indicating either
success or the failure reason, and it allows to specify details for the connection in the
schema portion of the URI. The uri parameter may be a comma- or whitespace-separated list
of URIs containing only the schema, the host, and the port fields. Apart from ldap, other
(non-standard) recognized values of the schema field are ldaps (LDAP over TLS), ldapi
(LDAP over IPC), and cldap (connectionless LDAP). If other fields are present, the
behavior is undefined.

At this time, ldap_open() and ldap_init() are deprecated in favor of ldap_initialize(),
essentially because the latter allows to specify a schema in the URI and it explicitly
returns an error code.

ldap_connect() causes a handle created by ldap_initialize() to connect to the server. This
is useful in situations where a file descriptor is required before a request is performed.

ldap_init_fd() allows an LDAP structure to be initialized using an already-opened
connection. The proto parameter should be one of LDAP_PROTO_TCP, LDAP_PROTO_UDP, or
LDAP_PROTO_IPC for a connection using TCP, UDP, or IPC, respectively. The value
LDAP_PROTO_EXT may also be specified if user-supplied sockbuf handlers are going to be
used. Note that support for UDP is not implemented unless libldap was built with
LDAP_CONNECTIONLESS defined. The uri parameter may optionally be provided for
informational purposes.

ldap_set_urllist_proc() allows to set a function proc of type LDAP_URLLIST_PROC that is
called when a successful connection can be established. This function receives the list
of URIs parsed from the uri string originally passed to ldap_initialize(), and the one
that successfully connected. The function may manipulate the URI list; the typical use
consists in moving the successful URI to the head of the list, so that subsequent attempts
to connect to one of the URIs using the same LDAP handle will try it first. If ld is
null, proc is set as a global parameter that is inherited by all handlers within the
process that are created after the call to ldap_set_urllist_proc(). By default, no
LDAP_URLLIST_PROC is set. In a multithreaded environment, ldap_set_urllist_proc() must be
called before any concurrent operation using the LDAP handle is started.

Note: the first call into the LDAP library also initializes the global options for the
library. As such the first call should be single-threaded or otherwise protected to insure
that only one call is active. It is recommended that ldap_get_option() or
ldap_set_option() be used in the program's main thread before any additional threads are
created. See ldap_get_option(3).

ERRORS

       If an error occurs, ldap_open() and ldap_init() will return NULL and errno should  be  set
       appropriately.   ldap_initialize()  and  ldap_init_fd() will directly return the LDAP code
       associated to the error (or LDAP_SUCCESS in case of success); errno should be set as  well
       whenever  appropriate.   ldap_set_urllist_proc()  returns  LDAP_OPT_ERROR  on  error,  and
       LDAP_OPT_SUCCESS on success.

ACKNOWLEDGEMENTS