LDAP_GET_DN(3) LDAP_GET_DN(3)
NAME
ldap_get_dn, ldap_explode_dn, ldap_explode_rdn, ldap_dn2ufn - LDAP DN handling routines
LIBRARY
OpenLDAP LDAP (libldap, -lldap)
SYNOPSIS
#include <ldap.h>
char *ldap_get_dn( LDAP *ld, LDAPMessage *entry )
int ldap_str2dn( const char *str, LDAPDN **dn, unsigned flags )
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 )
DESCRIPTION
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 2253 "Lightweight Directory
Access Protocol (v3): UTF-8 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 compo-nents, components,
nents, which are stored in dn as ldap_ava structures, arranged in LDAPAVA, LDAPRDN, and LDAPDN terms,
defined as:
typedef struct ldap_ava {
char *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 2253, " ... an octothorpe character ('#' ASCII 35) followed
by the hexadecimal representation of each of the bytes of the BER encoding of the X.500 Attribute-Value." AttributeValue."
Value." 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 2253, 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 spa-ces spaces
ces 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 com-ponent component
ponent 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 }, depend-ing depending
ing 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 sepa-rated separated
rated 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 trail-ing trailing
ing 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).
ERRORS
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.
NOTES
These routines dynamically allocate memory that the caller must free.
SEE ALSO
ldap(3), ldap_error(3), ldap_first_entry(3), ldap_memfree(3), ldap_value_free(3)
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.
OpenLDAP 2.3.27 2006/08/19 LDAP_GET_DN(3)
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