Langue: en

Version: 2007/09/04 (mandriva - 22/10/07)

Section: 5 (Format de fichier)


slapo-dynlist - Dynamic List overlay to slapd




The dynlist overlay to slapd(8) allows expansion of dynamic groups and more. Any time an entry with a specific objectClass is being returned, the LDAP URI-valued occurrences of a specific attribute are expanded into the corresponding entries, and the values of the attributes listed in the URI are added to the original entry. No recursion is allowed, to avoid potential infinite loops. The resulting entry must comply with the LDAP data model, so constraints are enforced. For example, if a SINGLE-VALUE attribute is listed, only the first value results in the final entry. The above described behavior is disabled when the manageDSAit control (RFC 3296) is used. In that case, the contents of the dynamic group entry is returned; namely, the URLs are returned instead of being expanded.


The config directives that are specific to the dynlist overlay must be prefixed by dynlist-, to avoid potential conflicts with directives specific to the underlying database or to other stacked overlays.
overlay dynlist
This directive adds the dynlist overlay to the current database, or to the frontend, if used before any database instantiation; see slapd.conf(5) for details.

This slapd.conf configuration option is defined for the dynlist overlay. It may have multiple occurrences, and it must appear after the overlay directive.

dynlist-attrset <group-oc> <URL-ad> [<member-ad>]
The value <group-oc> is the name of the objectClass that triggers the dynamic expansion of the data.

The value <URL-ad> is the name of the attributeDescription that contains the URI that is expanded by the overlay; if none is present, no expansion occurs. If the intersection of the attributes requested by the search operation (or the asserted attribute for compares) and the attributes listed in the URI is empty, no expansion occurs for that specific URI. It must be a subtype of labeledURI.

The value <member-ad> is optional; if present, the overlay behaves as a dynamic group: this attribute will list the DN of the entries resulting from the internal search. In this case, the <attrs> portion of the URI must be absent, and the DNs of all the entries resulting from the expansion of the URI are listed as values of this attribute. Compares that assert the value of the <member-ad> attribute of entries with <group-oc> objectClass apply as if the DN of the entries resulting from the expansion of the URI were present in the <group-oc> entry as values of the <member-ad> attribute.

The dynlist overlay may be used with any backend, but it is mainly intended for use with local storage backends. In case the URI expansion is very resource-intensive and occurs frequently with well-defined patterns, one should consider adding a proxycache later on in the overlay stack.


By default the expansions are performed using the identity of the current LDAP user. This identity may be overridden by setting the dgIdentity attribute to the DN of another LDAP user. In that case the dgIdentity will be used when expanding the URIs in the object. Setting the dgIdentity to a zero-length string will cause the expansions to be performed anonymously. Note that the dgIdentity attribute is defined in the dyngroup schema, and this schema must be loaded before the dgIdentity authorization feature may be used.


This example collects all the email addresses of a database into a single entry; first of all, make sure that slapd.conf contains the directives:
     include /path/to/dyngroup.schema
     # ...
     database <database>
     # ...
     overlay dynlist
     dynlist-attrset groupOfURLs memberURL

and that slapd loads, if compiled as a run-time module; then add to the database an entry like

     dn: cn=Dynamic List,ou=Groups,dc=example,dc=com
     objectClass: groupOfURLs
     cn: Dynamic List
     memberURL: ldap:///ou=People,dc=example,dc=com?mail?sub?(objectClass=person)

If no <attrs> are provided in the URI, all (non-operational) attributes are collected.

This example implements the dynamic group feature on the member attribute:

     include /path/to/dyngroup.schema
     # ...
     database <database>
     # ...
     overlay dynlist
     dynlist-attrset groupOfURLs memberURL member

A dynamic group with dgIdentity authorization could be created with an entry like

     dn: cn=Dynamic Group,ou=Groups,dc=example,dc=com
     objectClass: groupOfURLs
     objectClass: dgIdentityAux
     cn: Dynamic Group
     memberURL: ldap:///ou=People,dc=example,dc=com??sub?(objectClass=person)
     dgIdentity: cn=Group Proxy,ou=Services,dc=example,dc=com


default slapd configuration file


slapd.conf(5), slapd(8). The slapo-dynlist(5) overlay supports dynamic configuration via back-config.


This module was written in 2004 by Pierangelo Masarati for SysNet s.n.c.