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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  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,
       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 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).

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