X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=servers%2Fslapd%2Fbackover.c;h=3ffd18828508066aff7add1f0da3246b26808a82;hb=672f8ef3f39ed6008c1ff267847e32de59c5eeaf;hp=43299c1e0689019dbc1150401ee681e142892c66;hpb=0fe40e4ebdf0f1be5e96c5b7ad445bd2ec58d157;p=openldap

diff --git a/servers/slapd/backover.c b/servers/slapd/backover.c
index 43299c1e06..3ffd188285 100644
--- a/servers/slapd/backover.c
+++ b/servers/slapd/backover.c
@@ -2,7 +2,7 @@
 /* $OpenLDAP$ */
 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
  *
- * Copyright 2003-2004 The OpenLDAP Foundation.
+ * Copyright 2003-2006 The OpenLDAP Foundation.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -25,10 +25,16 @@
 
 #define SLAPD_TOOLS
 #include "slap.h"
+#include "config.h"
 
 static slap_overinst *overlays;
 
-enum db_which { db_open = 0, db_close, db_destroy };
+enum db_which {
+	db_open = 0,
+	db_close,
+	db_destroy,
+	db_last
+};
 
 static int
 over_db_func(
@@ -71,10 +77,13 @@ over_db_config(
 	slap_overinfo *oi = be->bd_info->bi_private;
 	slap_overinst *on = oi->oi_list;
 	BackendInfo *bi_orig = be->bd_info;
+	struct ConfigOCs *be_cf_ocs = be->be_cf_ocs;
+	ConfigArgs ca = {0};
 	int rc = 0;
 
 	if ( oi->oi_orig->bi_db_config ) {
 		be->bd_info = oi->oi_orig;
+		be->be_cf_ocs = oi->oi_orig->bi_cf_ocs;
 		rc = oi->oi_orig->bi_db_config( be, fname, lineno,
 			argc, argv );
 
@@ -123,8 +132,27 @@ over_db_config(
 		if ( rc != SLAP_CONF_UNKNOWN ) return rc;
 	}
 
+	ca.argv = argv;
+	ca.argc = argc;
+	ca.fname = fname;
+	ca.lineno = lineno;
+	ca.be = be;
+	snprintf( ca.log, sizeof( ca.log ), "%s: line %d",
+			ca.fname, ca.lineno );
+
 	for (; on; on=on->on_next) {
-		if (on->on_bi.bi_db_config) {
+		rc = SLAP_CONF_UNKNOWN;
+		if (on->on_bi.bi_cf_ocs) {
+			ConfigTable *ct;
+			ca.bi = &on->on_bi;
+			ct = config_find_keyword( on->on_bi.bi_cf_ocs->co_table, &ca );
+			if ( ct ) {
+				rc = config_add_vals( ct, &ca );
+				if ( rc != SLAP_CONF_UNKNOWN )
+					break;
+			}
+		}
+		if (on->on_bi.bi_db_config && rc == SLAP_CONF_UNKNOWN) {
 			be->bd_info = &on->on_bi;
 			rc = on->on_bi.bi_db_config( be, fname, lineno,
 				argc, argv );
@@ -132,6 +160,8 @@ over_db_config(
 		}
 	}
 	be->bd_info = bi_orig;
+	be->be_cf_ocs = be_cf_ocs;
+	
 	return rc;
 }
 
@@ -180,10 +210,13 @@ over_db_destroy(
 
 	rc = over_db_func( be, db_destroy );
 
-	for (next = on->on_next; on; on=next) {
-		next = on->on_next;
-		free( on );
+	if ( on ) {
+		for (next = on->on_next; on; on=next) {
+			next = on->on_next;
+			free( on );
+		}
 	}
+
 	free( oi );
 	return rc;
 }
@@ -209,32 +242,226 @@ over_back_response ( Operation *op, SlapReply *rs )
 	return rc;
 }
 
-enum op_which {
-	op_bind = 0,
-	op_unbind,
-	op_search,
-	op_compare,
-	op_modify,
-	op_modrdn,
-	op_add,
-	op_delete,
-	op_abandon,
-	op_cancel,
-	op_extended,
-	op_aux_operational,
-	op_aux_chk_referrals,
-	op_last
-};
+static int
+over_access_allowed(
+	Operation		*op,
+	Entry			*e,
+	AttributeDescription	*desc,
+	struct berval		*val,
+	slap_access_t		access,
+	AccessControlState	*state,
+	slap_mask_t		*maskp )
+{
+	slap_overinfo *oi;
+	slap_overinst *on;
+	BackendInfo *bi;
+	BackendDB *be = op->o_bd, db;
+	int rc = SLAP_CB_CONTINUE;
+
+	/* FIXME: used to happen for instance during abandon
+	 * when global overlays are used... */
+	assert( op->o_bd != NULL );
+
+	bi = op->o_bd->bd_info;
+	/* Were we invoked on the frontend? */
+	if ( !bi->bi_access_allowed ) {
+		oi = frontendDB->bd_info->bi_private;
+	} else {
+		oi = op->o_bd->bd_info->bi_private;
+	}
+	on = oi->oi_list;
+
+	for ( ; on; on = on->on_next ) {
+		if ( on->on_bi.bi_access_allowed ) {
+			/* NOTE: do not copy the structure until required */
+		 	if ( !SLAP_ISOVERLAY( op->o_bd ) ) {
+ 				db = *op->o_bd;
+				db.be_flags |= SLAP_DBFLAG_OVERLAY;
+				op->o_bd = &db;
+			}
+
+			op->o_bd->bd_info = (BackendInfo *)on;
+			rc = on->on_bi.bi_access_allowed( op, e,
+				desc, val, access, state, maskp );
+			if ( rc != SLAP_CB_CONTINUE ) break;
+		}
+	}
+
+	if ( rc == SLAP_CB_CONTINUE ) {
+		BI_access_allowed	*bi_access_allowed;
+
+		/* if the database structure was changed, o_bd points to a
+		 * copy of the structure; put the original bd_info in place */
+		if ( SLAP_ISOVERLAY( op->o_bd ) ) {
+			op->o_bd->bd_info = oi->oi_orig;
+		}
+
+		if ( oi->oi_orig->bi_access_allowed ) {
+			bi_access_allowed = oi->oi_orig->bi_access_allowed;
+		} else {
+			bi_access_allowed = slap_access_allowed;
+		}
+
+		rc = bi_access_allowed( op, e,
+			desc, val, access, state, maskp );
+	}
+	/* should not fall thru this far without anything happening... */
+	if ( rc == SLAP_CB_CONTINUE ) {
+		/* access not allowed */
+		rc = 0;
+	}
+
+	op->o_bd = be;
+	op->o_bd->bd_info = bi;
+
+	return rc;
+}
+
+static int
+over_acl_group(
+	Operation		*op,
+	Entry			*e,
+	struct berval		*gr_ndn,
+	struct berval		*op_ndn,
+	ObjectClass		*group_oc,
+	AttributeDescription	*group_at )
+{
+	slap_overinfo *oi;
+	slap_overinst *on;
+	BackendInfo *bi = op->o_bd->bd_info;
+	BackendDB *be = op->o_bd, db;
+	int rc = SLAP_CB_CONTINUE;
+
+	/* FIXME: used to happen for instance during abandon
+	 * when global overlays are used... */
+	assert( op->o_bd != NULL );
+
+	oi = op->o_bd->bd_info->bi_private;
+	on = oi->oi_list;
+
+	for ( ; on; on = on->on_next ) {
+		if ( on->on_bi.bi_acl_group ) {
+			/* NOTE: do not copy the structure until required */
+		 	if ( !SLAP_ISOVERLAY( op->o_bd ) ) {
+ 				db = *op->o_bd;
+				db.be_flags |= SLAP_DBFLAG_OVERLAY;
+				op->o_bd = &db;
+			}
+
+			op->o_bd->bd_info = (BackendInfo *)on;
+			rc = on->on_bi.bi_acl_group( op, e,
+				gr_ndn, op_ndn, group_oc, group_at );
+			if ( rc != SLAP_CB_CONTINUE ) break;
+		}
+	}
+
+	if ( rc == SLAP_CB_CONTINUE ) {
+		BI_acl_group		*bi_acl_group;
+
+		/* if the database structure was changed, o_bd points to a
+		 * copy of the structure; put the original bd_info in place */
+		if ( SLAP_ISOVERLAY( op->o_bd ) ) {
+			op->o_bd->bd_info = oi->oi_orig;
+		}
+
+		if ( oi->oi_orig->bi_acl_group ) {
+			bi_acl_group = oi->oi_orig->bi_acl_group;
+		} else {
+			bi_acl_group = backend_group;
+		}
+
+		rc = bi_acl_group( op, e,
+			gr_ndn, op_ndn, group_oc, group_at );
+	}
+	/* should not fall thru this far without anything happening... */
+	if ( rc == SLAP_CB_CONTINUE ) {
+		/* access not allowed */
+		rc = 0;
+	}
+
+	op->o_bd = be;
+	op->o_bd->bd_info = bi;
+
+	return rc;
+}
+
+static int
+over_acl_attribute(
+	Operation		*op,
+	Entry			*target,
+	struct berval		*entry_ndn,
+	AttributeDescription	*entry_at,
+	BerVarray		*vals,
+	slap_access_t		access )
+{
+	slap_overinfo *oi;
+	slap_overinst *on;
+	BackendInfo *bi = op->o_bd->bd_info;
+	BackendDB *be = op->o_bd, db;
+	int rc = SLAP_CB_CONTINUE;
+
+	/* FIXME: used to happen for instance during abandon
+	 * when global overlays are used... */
+	assert( op->o_bd != NULL );
+
+	oi = op->o_bd->bd_info->bi_private;
+	on = oi->oi_list;
+
+	for ( ; on; on = on->on_next ) {
+		if ( on->on_bi.bi_acl_attribute ) {
+			/* NOTE: do not copy the structure until required */
+		 	if ( !SLAP_ISOVERLAY( op->o_bd ) ) {
+ 				db = *op->o_bd;
+				db.be_flags |= SLAP_DBFLAG_OVERLAY;
+				op->o_bd = &db;
+			}
+
+			op->o_bd->bd_info = (BackendInfo *)on;
+			rc = on->on_bi.bi_acl_attribute( op, target,
+				entry_ndn, entry_at, vals, access );
+			if ( rc != SLAP_CB_CONTINUE ) break;
+		}
+	}
+
+	if ( rc == SLAP_CB_CONTINUE ) {
+		BI_acl_attribute		*bi_acl_attribute;
+
+		/* if the database structure was changed, o_bd points to a
+		 * copy of the structure; put the original bd_info in place */
+		if ( SLAP_ISOVERLAY( op->o_bd ) ) {
+			op->o_bd->bd_info = oi->oi_orig;
+		}
+
+		if ( oi->oi_orig->bi_acl_attribute ) {
+			bi_acl_attribute = oi->oi_orig->bi_acl_attribute;
+		} else {
+			bi_acl_attribute = backend_attribute;
+		}
+
+		rc = bi_acl_attribute( op, target,
+			entry_ndn, entry_at, vals, access );
+	}
+	/* should not fall thru this far without anything happening... */
+	if ( rc == SLAP_CB_CONTINUE ) {
+		/* access not allowed */
+		rc = 0;
+	}
+
+	op->o_bd = be;
+	op->o_bd->bd_info = bi;
+
+	return rc;
+}
 
 /*
  * default return code in case of missing backend function
  * and overlay stack returning SLAP_CB_CONTINUE
  */
-static int op_rc[] = {
+static int op_rc[ op_last ] = {
 	LDAP_UNWILLING_TO_PERFORM,	/* bind */
 	LDAP_UNWILLING_TO_PERFORM,	/* unbind */
 	LDAP_UNWILLING_TO_PERFORM,	/* search */
-	LDAP_UNWILLING_TO_PERFORM,	/* compare */
+	SLAP_CB_CONTINUE,		/* compare; pass to frontend */
 	LDAP_UNWILLING_TO_PERFORM,	/* modify */
 	LDAP_UNWILLING_TO_PERFORM,	/* modrdn */
 	LDAP_UNWILLING_TO_PERFORM,	/* add */
@@ -243,27 +470,72 @@ static int op_rc[] = {
 	LDAP_UNWILLING_TO_PERFORM,	/* cancel */
 	LDAP_UNWILLING_TO_PERFORM,	/* extended */
 	LDAP_SUCCESS,			/* aux_operational */
-	LDAP_SUCCESS			/* aux_chk_referrals */
+	LDAP_SUCCESS,			/* aux_chk_referrals */
+	SLAP_CB_CONTINUE		/* aux_chk_controls; pass to frontend */
 };
 
+int overlay_op_walk(
+	Operation *op,
+	SlapReply *rs,
+	slap_operation_t which,
+	slap_overinfo *oi,
+	slap_overinst *on
+)
+{
+	BI_op_bind **func;
+	int rc = SLAP_CB_CONTINUE;
+
+	for (; on; on=on->on_next ) {
+		func = &on->on_bi.bi_op_bind;
+		if ( func[which] ) {
+			op->o_bd->bd_info = (BackendInfo *)on;
+			rc = func[which]( op, rs );
+			if ( rc != SLAP_CB_CONTINUE ) break;
+		}
+	}
+
+	func = &oi->oi_orig->bi_op_bind;
+	if ( func[which] && rc == SLAP_CB_CONTINUE ) {
+		op->o_bd->bd_info = oi->oi_orig;
+		rc = func[which]( op, rs );
+	}
+	/* should not fall thru this far without anything happening... */
+	if ( rc == SLAP_CB_CONTINUE ) {
+		rc = op_rc[ which ];
+	}
+
+	/* The underlying backend didn't handle the request, make sure
+	 * overlay cleanup is processed.
+	 */
+	if ( rc == LDAP_UNWILLING_TO_PERFORM ) {
+		slap_callback *sc_next;
+		for ( ; op->o_callback && op->o_callback->sc_response !=
+			over_back_response; op->o_callback = sc_next ) {
+			sc_next = op->o_callback->sc_next;
+			if ( op->o_callback->sc_cleanup ) {
+				op->o_callback->sc_cleanup( op, rs );
+			}
+		}
+	}
+	return rc;
+}
+
 static int
 over_op_func(
 	Operation *op,
 	SlapReply *rs,
-	enum op_which which
+	slap_operation_t which
 )
 {
 	slap_overinfo *oi;
 	slap_overinst *on;
-	BI_op_bind **func;
 	BackendDB *be = op->o_bd, db;
 	slap_callback cb = {NULL, over_back_response, NULL, NULL};
 	int rc = SLAP_CB_CONTINUE;
 
-	if ( op->o_bd == NULL ) {
-		/* FIXME: happens for instance during abandon... */
-		return 0;
-	}
+	/* FIXME: used to happen for instance during abandon
+	 * when global overlays are used... */
+	assert( op->o_bd != NULL );
 
 	oi = op->o_bd->bd_info->bi_private;
 	on = oi->oi_list;
@@ -277,24 +549,8 @@ over_op_func(
 	cb.sc_private = oi;
 	op->o_callback = &cb;
 
-	for (; on; on=on->on_next ) {
-		func = &on->on_bi.bi_op_bind;
-		if ( func[which] ) {
-			db.bd_info = (BackendInfo *)on;
-			rc = func[which]( op, rs );
-			if ( rc != SLAP_CB_CONTINUE ) break;
-		}
-	}
+	rc = overlay_op_walk( op, rs, which, oi, on );
 
-	func = &oi->oi_orig->bi_op_bind;
-	if ( func[which] && rc == SLAP_CB_CONTINUE ) {
-		db.bd_info = oi->oi_orig;
-		rc = func[which]( op, rs );
-	}
-	/* should not fall thru this far without anything happening... */
-	if ( rc == SLAP_CB_CONTINUE ) {
-		rc = op_rc[ which ];
-	}
 	op->o_bd = be;
 	op->o_callback = cb.sc_next;
 	return rc;
@@ -378,11 +634,152 @@ over_aux_chk_referrals( Operation *op, SlapReply *rs )
 	return over_op_func( op, rs, op_aux_chk_referrals );
 }
 
+static int
+over_aux_chk_controls( Operation *op, SlapReply *rs )
+{
+	return over_op_func( op, rs, op_aux_chk_controls );
+}
+
+enum conn_which {
+	conn_init = 0,
+	conn_destroy,
+	conn_last
+};
+
+static int
+over_connection_func(
+	BackendDB	*bd,
+	Connection	*conn,
+	enum conn_which	which
+)
+{
+	slap_overinfo		*oi;
+	slap_overinst		*on;
+	BackendDB		db;
+	int			rc = SLAP_CB_CONTINUE;
+	BI_connection_init	**func;
+
+	/* FIXME: used to happen for instance during abandon
+	 * when global overlays are used... */
+	assert( bd != NULL );
+
+	oi = bd->bd_info->bi_private;
+	on = oi->oi_list;
+
+ 	if ( !SLAP_ISOVERLAY( bd ) ) {
+ 		db = *bd;
+		db.be_flags |= SLAP_DBFLAG_OVERLAY;
+		bd = &db;
+	}
+
+	for ( ; on; on = on->on_next ) {
+		func = &on->on_bi.bi_connection_init;
+		if ( func[ which ] ) {
+			bd->bd_info = (BackendInfo *)on;
+			rc = func[ which ]( bd, conn );
+			if ( rc != SLAP_CB_CONTINUE ) break;
+		}
+	}
+
+	func = &oi->oi_orig->bi_connection_init;
+	if ( func[ which ] && rc == SLAP_CB_CONTINUE ) {
+		bd->bd_info = oi->oi_orig;
+		rc = func[ which ]( bd, conn );
+	}
+	/* should not fall thru this far without anything happening... */
+	if ( rc == SLAP_CB_CONTINUE ) {
+		rc = LDAP_UNWILLING_TO_PERFORM;
+	}
+
+	return rc;
+}
+
+static int
+over_connection_init(
+	BackendDB	*bd,
+	Connection	*conn
+)
+{
+	return over_connection_func( bd, conn, conn_init );
+}
+
+static int
+over_connection_destroy(
+	BackendDB	*bd,
+	Connection	*conn
+)
+{
+	return over_connection_func( bd, conn, conn_destroy );
+}
+
 int
 overlay_register(
 	slap_overinst *on
 )
 {
+	slap_overinst	*tmp;
+
+	/* FIXME: check for duplicates? */
+	for ( tmp = overlays; tmp != NULL; tmp = tmp->on_next ) {
+		if ( strcmp( on->on_bi.bi_type, tmp->on_bi.bi_type ) == 0 ) {
+			Debug( LDAP_DEBUG_ANY,
+				"overlay_register(\"%s\"): "
+				"name already in use.\n",
+				on->on_bi.bi_type, 0, 0 );
+			return -1;
+		}
+
+		if ( on->on_bi.bi_obsolete_names != NULL ) {
+			int	i;
+
+			for ( i = 0; on->on_bi.bi_obsolete_names[ i ] != NULL; i++ ) {
+				if ( strcmp( on->on_bi.bi_obsolete_names[ i ], tmp->on_bi.bi_type ) == 0 ) {
+					Debug( LDAP_DEBUG_ANY,
+						"overlay_register(\"%s\"): "
+						"obsolete name \"%s\" already in use "
+						"by overlay \"%s\".\n",
+						on->on_bi.bi_type,
+						on->on_bi.bi_obsolete_names[ i ],
+						tmp->on_bi.bi_type );
+					return -1;
+				}
+			}
+		}
+
+		if ( tmp->on_bi.bi_obsolete_names != NULL ) {
+			int	i;
+
+			for ( i = 0; tmp->on_bi.bi_obsolete_names[ i ] != NULL; i++ ) {
+				int	j;
+
+				if ( strcmp( on->on_bi.bi_type, tmp->on_bi.bi_obsolete_names[ i ] ) == 0 ) {
+					Debug( LDAP_DEBUG_ANY,
+						"overlay_register(\"%s\"): "
+						"name already in use "
+						"as obsolete by overlay \"%s\".\n",
+						on->on_bi.bi_type,
+						tmp->on_bi.bi_obsolete_names[ i ], 0 );
+					return -1;
+				}
+
+				if ( on->on_bi.bi_obsolete_names != NULL ) {
+					for ( j = 0; on->on_bi.bi_obsolete_names[ j ] != NULL; j++ ) {
+						if ( strcmp( on->on_bi.bi_obsolete_names[ j ], tmp->on_bi.bi_obsolete_names[ i ] ) == 0 ) {
+							Debug( LDAP_DEBUG_ANY,
+								"overlay_register(\"%s\"): "
+								"obsolete name \"%s\" already in use "
+								"as obsolete by overlay \"%s\".\n",
+								on->on_bi.bi_type,
+								on->on_bi.bi_obsolete_names[ j ],
+								tmp->on_bi.bi_type );
+							return -1;
+						}
+					}
+				}
+			}
+		}
+	}
+
 	on->on_next = overlays;
 	overlays = on;
 	return 0;
@@ -390,8 +787,8 @@ overlay_register(
 
 /*
  * iterator on registered overlays; overlay_next( NULL ) returns the first
- * overlay; * subsequent calls with the previously returned value allow to 
- * iterate * over the entire list; returns NULL when no more overlays are 
+ * overlay; subsequent calls with the previously returned value allow to 
+ * iterate over the entire list; returns NULL when no more overlays are 
  * registered.
  */
 
@@ -417,14 +814,30 @@ overlay_find( const char *over_type )
 {
 	slap_overinst *on = overlays;
 
-	assert( over_type );
+	assert( over_type != NULL );
 
 	for ( ; on; on = on->on_next ) {
 		if ( strcmp( on->on_bi.bi_type, over_type ) == 0 ) {
-			break;
+			goto foundit;
+		}
+
+		if ( on->on_bi.bi_obsolete_names != NULL ) {
+			int	i;
+
+			for ( i = 0; on->on_bi.bi_obsolete_names[ i ] != NULL; i++ ) {
+				if ( strcmp( on->on_bi.bi_obsolete_names[ i ], over_type ) == 0 ) {
+					Debug( LDAP_DEBUG_ANY,
+						"overlay_find(\"%s\"): "
+						"obsolete name for \"%s\".\n",
+						on->on_bi.bi_obsolete_names[ i ],
+						on->on_bi.bi_type, 0 );
+					goto foundit;
+				}
+			}
 		}
 	}
 
+foundit:;
 	return on;
 }
 
@@ -452,7 +865,7 @@ overlay_is_inst( BackendDB *be, const char *over_type )
 {
 	slap_overinst	*on;
 
-	assert( be );
+	assert( be != NULL );
 
 	if ( !overlay_is_over( be ) ) {
 		return 0;
@@ -468,6 +881,60 @@ overlay_is_inst( BackendDB *be, const char *over_type )
 	return 0;
 }
 
+int
+overlay_register_control( BackendDB *be, const char *oid )
+{
+	int		gotit = 0;
+	int		cid;
+
+	if ( slap_find_control_id( oid, &cid ) == LDAP_CONTROL_NOT_FOUND ) {
+		return -1;
+	}
+
+	if ( SLAP_ISGLOBALOVERLAY( be ) ) {
+		BackendDB *bd;
+		
+		/* add to all backends... */
+		LDAP_STAILQ_FOREACH( bd, &backendDB, be_next ) {
+			if ( be == bd ) {
+				gotit = 1;
+			}
+
+			bd->be_ctrls[ cid ] = 1;
+			bd->be_ctrls[ SLAP_MAX_CIDS ] = 1;
+		}
+
+	}
+	
+	if ( !gotit ) {
+		be->be_ctrls[ cid ] = 1;
+		be->be_ctrls[ SLAP_MAX_CIDS ] = 1;
+	}
+
+	return 0;
+}
+
+void
+overlay_destroy_one( BackendDB *be, slap_overinst *on )
+{
+	slap_overinfo *oi = on->on_info;
+	slap_overinst **oidx;
+
+	for ( oidx = &oi->oi_list; *oidx; oidx = &(*oidx)->on_next ) {
+		if ( *oidx == on ) {
+			*oidx = on->on_next;
+			if ( on->on_bi.bi_db_destroy ) {
+				BackendInfo *bi_orig = be->bd_info;
+				be->bd_info = (BackendInfo *)on;
+				on->on_bi.bi_db_destroy( be );
+				be->bd_info = bi_orig;
+			}
+			free( on );
+			break;
+		}
+	}
+}
+
 /* add an overlay to a particular backend. */
 int
 overlay_config( BackendDB *be, const char *ov )
@@ -486,9 +953,35 @@ overlay_config( BackendDB *be, const char *ov )
 	 * overlay info structure
 	 */
 	if ( !overlay_is_over( be ) ) {
+		int	isglobal = 0;
+
+		/* NOTE: the first time a global overlay is configured,
+		 * frontendDB gets this flag; it is used later by overlays
+		 * to determine if they're stacked on top of the frontendDB */
+		if ( be->bd_info == frontendDB->bd_info || SLAP_ISGLOBALOVERLAY( be ) ) {
+			isglobal = 1;
+			if ( on->on_bi.bi_flags & SLAPO_BFLAG_DBONLY ) {
+				Debug( LDAP_DEBUG_ANY, "overlay_config(): "
+					"overlay \"%s\" cannot be global.\n",
+					ov, 0, 0 );
+				return 1;
+			}
+
+		} else if ( on->on_bi.bi_flags & SLAPO_BFLAG_GLOBONLY ) {
+			Debug( LDAP_DEBUG_ANY, "overlay_config(): "
+				"overlay \"%s\" can only be global.\n",
+				ov, 0, 0 );
+			return 1;
+		}
+
 		oi = ch_malloc( sizeof( slap_overinfo ) );
 		oi->oi_orig = be->bd_info;
 		oi->oi_bi = *be->bd_info;
+		oi->oi_origdb = be;
+
+		if ( isglobal ) {
+			SLAP_DBFLAGS( be ) |= SLAP_DBFLAG_GLOBAL_OVERLAY;
+		}
 
 		/* Save a pointer to ourself in bi_private.
 		 */
@@ -524,14 +1017,26 @@ overlay_config( BackendDB *be, const char *ov )
 		 */
 		bi->bi_operational = over_aux_operational;
 		bi->bi_chk_referrals = over_aux_chk_referrals;
+		bi->bi_chk_controls = over_aux_chk_controls;
+
+		/* these have specific arglists */
+		bi->bi_access_allowed = over_access_allowed;
+		bi->bi_acl_group = over_acl_group;
+		bi->bi_acl_attribute = over_acl_attribute;
+		
+		bi->bi_connection_init = over_connection_init;
+		bi->bi_connection_destroy = over_connection_destroy;
 
 		be->bd_info = bi;
 
 	} else {
 		if ( overlay_is_inst( be, ov ) ) {
 			Debug( LDAP_DEBUG_ANY, "overlay_config(): "
-					"warning, overlay \"%s\" "
-					"already in list\n", ov, 0, 0 );
+				"overlay \"%s\" already in list\n",
+				ov, 0, 0 );
+			if ( SLAPO_SINGLE( be ) ) {
+				return 1;
+			}
 		}
 
 		oi = be->bd_info->bi_private;
@@ -548,9 +1053,15 @@ overlay_config( BackendDB *be, const char *ov )
 
 	/* Any initialization needed? */
 	if ( on->on_bi.bi_db_init ) {
+		int rc;
 		be->bd_info = (BackendInfo *)on2;
-		on2->on_bi.bi_db_init( be );
+		rc = on2->on_bi.bi_db_init( be );
 		be->bd_info = (BackendInfo *)oi;
+		if ( rc ) {
+			oi->oi_list = on2->on_next;
+			ch_free( on2 );
+			return rc;
+		}
 	}
 
 	return 0;