all-operational overlay: allows to configure part of te DIT so that requests

with requested attribute lists empty or containing "*" are expanded
to contain "+" as well, so that all operational attributes are returned.
This may be required to work around dumb clients that interrogate
the rootDSE requesting "*" and expecting operational attributes to be
returned as well.  To make it a bit more generic, it can be configured
to do the same for an arbitrary search described by an URI.  For example,

overlay		allop
allop-URI	ldap:///??sub

before any database instantiation causes all searches to return "*","+"
when ors_attrs is NULL or countains "*".

servers/slapd/overlays/allop.c

+/* allop.c - returns all operational attributes when appropriate */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2005 The OpenLDAP Foundation.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was initially developed by Pierangelo Masarati for inclusion in
+ * OpenLDAP Software.
+ */
+
+/*
+ * The intended usage is as a global overlay for use with those clients
+ * that do not make use of the RFC3673 allOp ("+") in the requested 
+ * attribute list, but expect all operational attributes to be returned.
+ * Usage: add
+ *
+
+overlay		allop
+allop-URI	<ldapURI>
+
+ *
+ * if the allop-URI is not given, the rootDSE, i.e. "ldap:///??base",
+ * is assumed.
+ */
+
+#include "portable.h"
+
+#ifdef SLAPD_OVER_ALLOP
+
+#include <stdio.h>
+#include <ac/string.h>
+
+#include "slap.h"
+
+typedef struct allop_t {
+	struct berval	ao_ndn;
+	int		ao_scope;
+} allop_t;
+
+static int
+allop_db_config(
+	BackendDB	*be,
+	const char	*fname,
+	int		lineno,
+	int		argc,
+	char		**argv )
+{
+	slap_overinst	*on = (slap_overinst *)be->bd_info;
+	allop_t		*ao = (allop_t *)on->on_bi.bi_private;
+
+	if ( strcasecmp( argv[ 0 ], "allop-uri" ) == 0 ) {
+		LDAPURLDesc	*lud;
+		struct berval	dn,
+				ndn;
+		int		scope,
+				rc = LDAP_SUCCESS;
+
+		if ( argc != 2 ) {
+			fprintf( stderr, "%s line %d: "
+				"need exactly 1 arg "
+				"in \"allop-uri <ldapURI>\" "
+				"directive.\n",
+				fname, lineno );
+			return 1;
+		}
+
+		if ( ldap_url_parse( argv[ 1 ], &lud ) != LDAP_URL_SUCCESS ) {
+			return -1;
+		}
+
+		scope = lud->lud_scope;
+		if ( scope == LDAP_SCOPE_DEFAULT ) {
+			scope = LDAP_SCOPE_BASE;
+		}
+
+		if ( lud->lud_dn == NULL || lud->lud_dn[ 0 ] == '\0' ) {
+			if ( scope == LDAP_SCOPE_BASE ) {
+				BER_BVZERO( &ndn );
+
+			} else {
+				ber_str2bv( "", 0, 1, &ndn );
+			}
+
+		} else {
+
+			ber_str2bv( lud->lud_dn, 0, 0, &dn );
+			rc = dnNormalize( 0, NULL, NULL, &dn, &ndn, NULL );
+		}
+
+		ldap_free_urldesc( lud );
+		if ( rc != LDAP_SUCCESS ) {
+			return -1;
+		}
+
+		if ( BER_BVISNULL( &ndn ) ) {
+			/* rootDSE */
+			if ( ao != NULL ) {
+				ch_free( ao->ao_ndn.bv_val );
+				ch_free( ao );
+				on->on_bi.bi_private = NULL;
+			}
+
+		} else {
+			if ( ao == NULL ) {
+				ao = ch_calloc( 1, sizeof( allop_t ) );
+				on->on_bi.bi_private = (void *)ao;
+
+			} else {
+				ch_free( ao->ao_ndn.bv_val );
+			}
+
+			ao->ao_ndn = ndn;
+			ao->ao_scope = scope;
+		}
+
+	} else {
+		return SLAP_CONF_UNKNOWN;
+	}
+
+	return 0;
+}
+
+static int
+allop_db_destroy( BackendDB *be )
+{
+	slap_overinst	*on = (slap_overinst *)be->bd_info;
+	allop_t		*ao = (allop_t *)on->on_bi.bi_private;
+
+	if ( ao != NULL ) {
+		assert( !BER_BVISNULL( &ao->ao_ndn ) );
+
+		ch_free( ao->ao_ndn.bv_val );
+		ch_free( ao );
+		on->on_bi.bi_private = NULL;
+	}
+
+	return 0;
+}
+
+static int
+allop_op_search( Operation *op, SlapReply *rs )
+{
+	slap_overinst	*on = (slap_overinst *)op->o_bd->bd_info;
+	allop_t		*ao = (allop_t *)on->on_bi.bi_private;
+
+	slap_mask_t	mask;
+	int		i,
+			add_allUser = 0;
+
+	if ( ao == NULL ) {
+		if ( !BER_BVISEMPTY( &op->o_req_ndn )
+			|| op->ors_scope != LDAP_SCOPE_BASE )
+		{
+			return SLAP_CB_CONTINUE;
+		}
+
+	} else {
+		if ( !dnIsSuffix( &op->o_req_ndn, &ao->ao_ndn ) ) {
+			return SLAP_CB_CONTINUE;
+		}
+
+		switch ( ao->ao_scope ) {
+		case LDAP_SCOPE_BASE:
+			if ( op->o_req_ndn.bv_len != ao->ao_ndn.bv_len ) {
+				return SLAP_CB_CONTINUE;
+			}
+			break;
+
+		case LDAP_SCOPE_ONELEVEL:
+			if ( op->ors_scope == LDAP_SCOPE_BASE ) {
+				struct berval	rdn = op->o_req_ndn;
+
+				rdn.bv_len -= ao->ao_ndn.bv_len + STRLENOF( "," );
+				if ( !dnIsOneLevelRDN( &rdn ) ) {
+					return SLAP_CB_CONTINUE;
+				}
+
+				break;
+			}
+			return SLAP_CB_CONTINUE;
+
+		case LDAP_SCOPE_SUBTREE:
+			break;
+		}
+	}
+
+	mask = slap_attr_flags( op->ors_attrs );
+	if ( SLAP_OPATTRS( mask ) ) {
+		return SLAP_CB_CONTINUE;
+	}
+
+	if ( !SLAP_USERATTRS( mask ) ) {
+		return SLAP_CB_CONTINUE;
+	}
+
+	i = 0;
+	if ( op->ors_attrs == NULL ) {
+		add_allUser = 1;
+
+	} else {
+		for ( ; !BER_BVISNULL( &op->ors_attrs[ i ].an_name ); i++ )
+			;
+	}
+
+	op->ors_attrs = op->o_tmprealloc( op->ors_attrs,
+		sizeof( AttributeName ) * ( i + add_allUser + 2 ),
+		op->o_tmpmemctx );
+
+	if ( add_allUser ) {
+		op->ors_attrs[ i ] = slap_anlist_all_user_attributes[ 0 ];
+		i++;
+	}
+
+	op->ors_attrs[ i ] = slap_anlist_all_operational_attributes[ 0 ];
+
+	BER_BVZERO( &op->ors_attrs[ i + 1 ].an_name );
+
+	return SLAP_CB_CONTINUE;
+}
+
+static slap_overinst 		allop;
+
+int
+allop_init()
+{
+	allop.on_bi.bi_type = "allop";
+
+	allop.on_bi.bi_db_config = allop_db_config;
+	allop.on_bi.bi_db_destroy = allop_db_destroy;
+
+	allop.on_bi.bi_op_search = allop_op_search;
+
+	return overlay_register( &allop );
+}
+
+#if SLAPD_OVER_ALLOP == SLAPD_MOD_DYNAMIC
+int
+init_module( int argc, char *argv[] )
+{
+	return allop_init();
+}
+#endif /* SLAPD_OVER_ALLOP == SLAPD_MOD_DYNAMIC */
+
+#endif /* defined(SLAPD_OVER_ALLOP) */