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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | ERRORS | NOTES | SEE ALSO | ACKNOWLEDGEMENTS | COLOPHON |
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LDAP_GET_DN(3) Library Functions Manual LDAP_GET_DN(3)
ldap_get_dn, ldap_explode_dn, ldap_explode_rdn, ldap_dn2ufn - LDAP
DN handling routines
OpenLDAP LDAP (libldap, -lldap)
#include <ldap.h>
char *ldap_get_dn( LDAP *ld, LDAPMessage *entry )
int ldap_str2dn( const char *str, LDAPDN *dn, unsigned flags )
void ldap_dnfree( LDAPDN dn )
int ldap_dn2str( LDAPDN dn, char **str, unsigned flags )
char **ldap_explode_dn( const char *dn, int notypes )
char **ldap_explode_rdn( const char *rdn, int notypes )
char *ldap_dn2ufn( const char * dn )
char *ldap_dn2dcedn( const char * dn )
char *ldap_dcedn2dn( const char * dn )
char *ldap_dn2ad_canonical( const char * dn )
These routines allow LDAP entry names (Distinguished Names, or
DNs) to be obtained, parsed, converted to a user-friendly form,
and tested. A DN has the form described in RFC 4414 "Lightweight
Directory Access Protocol (LDAP): String Representation of
Distinguished Names".
The ldap_get_dn() routine takes an entry as returned by
ldap_first_entry(3) or ldap_next_entry(3) and returns a copy of
the entry's DN. Space for the DN will be obtained dynamically and
should be freed by the caller using ldap_memfree(3).
ldap_str2dn() parses a string representation of a distinguished
name contained in str into its components, which are stored in dn
as ldap_ava structures, arranged in LDAPAVA, LDAPRDN, and LDAPDN
terms. Space for dn will be obtained dynamically and should be
freed by the caller using ldap_dnfree(3). The LDAPDN is defined
as:
typedef struct ldap_ava {
struct berval la_attr;
struct berval la_value;
unsigned la_flags;
} LDAPAVA;
typedef LDAPAVA** LDAPRDN;
typedef LDAPRDN* LDAPDN;
The attribute types and the attribute values are not normalized.
The la_flags can be either LDAP_AVA_STRING or LDAP_AVA_BINARY, the
latter meaning that the value is BER/DER encoded and thus must be
represented as, quoting from RFC 4514, " ... an octothorpe
character ('#' ASCII 35) followed by the hexadecimal
representation of each of the bytes of the BER encoding of the
X.500 AttributeValue." The flags parameter to ldap_str2dn() can
be
LDAP_DN_FORMAT_LDAPV3
LDAP_DN_FORMAT_LDAPV2
LDAP_DN_FORMAT_DCE
which defines what DN syntax is expected (according to RFC 4514,
RFC 1779 and DCE, respectively). The format can be ORed to the
flags
LDAP_DN_P_NO_SPACES
LDAP_DN_P_NO_SPACE_AFTER_RDN
...
LDAP_DN_PEDANTIC
The latter is a shortcut for all the previous limitations.
LDAP_DN_P_NO_SPACES does not allow extra spaces in the dn; the
default is to silently eliminate spaces around AVA separators
('='), RDN component separators ('+' for LDAPv3/LDAPv2 or ',' for
DCE) and RDN separators (',' LDAPv3/LDAPv2 or '/' for DCE).
LDAP_DN_P_NO_SPACE_AFTER_RDN does not allow a single space after
RDN separators.
ldap_dn2str() performs the inverse operation, yielding in str a
string representation of dn. It allows the same values for flags
as ldap_str2dn(), plus
LDAP_DN_FORMAT_UFN
LDAP_DN_FORMAT_AD_CANONICAL
for user-friendly naming (RFC 1781) and AD canonical.
The following routines are viewed as deprecated in favor of
ldap_str2dn() and ldap_dn2str(). They are provided to support
legacy applications.
The ldap_explode_dn() routine takes a DN as returned by
ldap_get_dn() and breaks it up into its component parts. Each
part is known as a Relative Distinguished Name, or RDN.
ldap_explode_dn() returns a NULL-terminated array, each component
of which contains an RDN from the DN. The notypes parameter is
used to request that only the RDN values be returned, not their
types. For example, the DN "cn=Bob, c=US" would return as either
{ "cn=Bob", "c=US", NULL } or { "Bob", "US", NULL }, depending on
whether notypes was 0 or 1, respectively. Assertion values in RDN
strings may included escaped characters. The result can be freed
by calling ldap_value_free(3).
Similarly, the ldap_explode_rdn() routine takes an RDN as returned
by ldap_explode_dn(dn,0) and breaks it up into its "type=value"
component parts (or just "value", if the notypes parameter is
set). Note the value is not unescaped. The result can be freed
by calling ldap_value_free(3).
ldap_dn2ufn() is used to turn a DN as returned by ldap_get_dn(3)
into a more user-friendly form, stripping off all type names. See
"Using the Directory to Achieve User Friendly Naming" (RFC 1781)
for more details on the UFN format. Due to the ambiguous nature
of the format, it is generally only used for display purposes.
The space for the UFN returned is obtained dynamically and the
user is responsible for freeing it via a call to ldap_memfree(3).
ldap_dn2dcedn() is used to turn a DN as returned by ldap_get_dn(3)
into a DCE-style DN, e.g. a string with most-significant to least
significant rdns separated by slashes ('/'); rdn components are
separated by commas (','). Only printable chars (e.g. LDAPv2
printable string) are allowed, at least in this implementation.
ldap_dcedn2dn() performs the opposite operation.
ldap_dn2ad_canonical() turns a DN into a AD canonical name, which
is basically a DCE dn with attribute types omitted. The trailing
domain, if present, is turned in a DNS-like domain. The space for
the returned value is obtained dynamically and the user is
responsible for freeing it via a call to ldap_memfree(3).
If an error occurs in ldap_get_dn(), NULL is returned and the
ld_errno field in the ld parameter is set to indicate the error.
See ldap_error(3) for a description of possible error codes.
ldap_explode_dn(), ldap_explode_rdn(), ldap_dn2ufn(),
ldap_dn2dcedn(), ldap_dcedn2dn(), and ldap_dn2ad_canonical() will
return NULL with errno(3) set appropriately in case of trouble.
These routines dynamically allocate memory that the caller must
free.
ldap(3), ldap_error(3), ldap_first_entry(3), ldap_memfree(3),
ldap_value_free(3)
OpenLDAP Software is developed and maintained by The OpenLDAP
Project <http://www.openldap.org/>. OpenLDAP Software is derived
from the University of Michigan LDAP 3.3 Release.
This page is part of the OpenLDAP (an open source implementation
of the Lightweight Directory Access Protocol) project.
Information about the project can be found at
⟨http://www.openldap.org/⟩. If you have a bug report for this
manual page, see ⟨http://www.openldap.org/its/⟩. This page was
obtained from the project's upstream Git repository
⟨https://git.openldap.org/openldap/openldap.git⟩ on 2025-08-11.
(At that time, the date of the most recent commit that was found
in the repository was 2025-08-05.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
OpenLDAP LDVERSION RELEASEDATE LDAP_GET_DN(3)
Pages that refer to this page: ldap_first_entry(3), ldap_get_dn(3), ldap_sync(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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