From: Howard Chu <hyc@openldap.org>
Date: Mon, 10 Dec 2001 12:09:40 +0000 (+0000)
Subject: Changed backglue configuration. Added noSubordinates arg to select_backend
X-Git-Tag: LDBM_PRE_GIANT_RWLOCK~676
X-Git-Url: https://git.sur5r.net/?a=commitdiff_plain;h=ef0b308bea3741a5db2846aea0ab0608c2ffe5b9;p=openldap

Changed backglue configuration. Added noSubordinates arg to select_backend
to deal with glued subordinates.
---

diff --git a/servers/slapd/add.c b/servers/slapd/add.c
index 1af8aaeb47..046ae39378 100644
--- a/servers/slapd/add.c
+++ b/servers/slapd/add.c
@@ -203,7 +203,7 @@ do_add( Connection *conn, Operation *op )
 	 * appropriate one, or send a referral to our "referral server"
 	 * if we don't hold it.
 	 */
-	be = select_backend( e->e_ndn, manageDSAit );
+	be = select_backend( e->e_ndn, manageDSAit, 0 );
 	if ( be == NULL ) {
 		struct berval **ref = referral_rewrite( default_referral,
 			NULL, e->e_dn, LDAP_SCOPE_DEFAULT );
diff --git a/servers/slapd/back-bdb/back-bdb.h b/servers/slapd/back-bdb/back-bdb.h
index 1e55821395..0d3ad463c6 100644
--- a/servers/slapd/back-bdb/back-bdb.h
+++ b/servers/slapd/back-bdb/back-bdb.h
@@ -17,7 +17,7 @@ LDAP_BEGIN_DECL
 
 #define BDB_FILTER_INDICES 1
 /* #define BDB_IDL_MULTI		1 */
-/* #define BDB_HIER		1 */
+#define BDB_HIER		1
 
 #define DN_BASE_PREFIX		SLAP_INDEX_EQUALITY_PREFIX
 #define DN_ONE_PREFIX	 	'%'
diff --git a/servers/slapd/back-ldap/config.c b/servers/slapd/back-ldap/config.c
index f493b0d8e5..605a16ab2f 100644
--- a/servers/slapd/back-ldap/config.c
+++ b/servers/slapd/back-ldap/config.c
@@ -137,7 +137,7 @@ ldap_back_db_config(
 			return( 1 );
 		}
 		
-		tmp_be = select_backend( argv[1], 0 );
+		tmp_be = select_backend( argv[1], 0, 0 );
 		if ( tmp_be != NULL && tmp_be != be ) {
 			fprintf( stderr, "%s: line %d: suffix already in use"
 				       " by another backend in"
@@ -147,7 +147,7 @@ ldap_back_db_config(
 			return( 1 );						
 		}
 
-		tmp_be = select_backend( argv[2], 0 );
+		tmp_be = select_backend( argv[2], 0, 0 );
 		if ( tmp_be != NULL ) {
 			fprintf( stderr, "%s: line %d: massaged suffix"
 				       " already in use by another backend in" 
diff --git a/servers/slapd/back-meta/config.c b/servers/slapd/back-meta/config.c
index 35041ffe34..0cc797f7bf 100644
--- a/servers/slapd/back-meta/config.c
+++ b/servers/slapd/back-meta/config.c
@@ -213,7 +213,7 @@ meta_back_db_config(
 		 * uri MUST be a branch of suffix!
 		 */
 #if 0 /* too strict a constraint */
-		if ( select_backend( li->targets[ i ]->suffix, 0 ) != be ) {
+		if ( select_backend( li->targets[ i ]->suffix, 0, 0 ) != be ) {
 			fprintf( stderr,
 	"%s: line %d: <naming context> of URI does not refer to current backend"
 	" in \"uri <protocol>://<server>[:port]/<naming context>\" line\n",
@@ -224,7 +224,7 @@ meta_back_db_config(
 		/*
 		 * uri MUST be a branch of a suffix!
 		 */
-		if ( select_backend( li->targets[ i ]->suffix, 0 ) == NULL ) {
+		if ( select_backend( li->targets[ i ]->suffix, 0, 0 ) == NULL ) {
 			fprintf( stderr,
 	"%s: line %d: <naming context> of URI does not resolve to a backend"
 	" in \"uri <protocol>://<server>[:port]/<naming context>\" line\n",
@@ -419,7 +419,7 @@ meta_back_db_config(
 			return 1;
 		}
 		
-		tmp_be = select_backend( argv[ 1 ], 0 );
+		tmp_be = select_backend( argv[ 1 ], 0, 0 );
 		if ( tmp_be != NULL && tmp_be != be ) {
 			fprintf( stderr, 
 	"%s: line %d: suffix already in use by another backend in"
@@ -428,7 +428,7 @@ meta_back_db_config(
 			return 1;						
 		}
 
-		tmp_be = select_backend( argv[ 2 ], 0 );
+		tmp_be = select_backend( argv[ 2 ], 0, 0 );
 		if ( tmp_be != NULL ) {
 			fprintf( stderr,
 	"%s: line %d: massaged suffix already in use by another backend in" 
diff --git a/servers/slapd/back-monitor/init.c b/servers/slapd/back-monitor/init.c
index 5b46dca302..dfa020f54f 100644
--- a/servers/slapd/back-monitor/init.c
+++ b/servers/slapd/back-monitor/init.c
@@ -385,7 +385,7 @@ monitor_back_open(
 	 */
 	ndn = ch_strdup( SLAPD_MONITOR_DN );
 	dn_normalize( ndn );
-	be = select_backend( ndn , 0 );
+	be = select_backend( ndn , 0, 0 );
 	ch_free( ndn );
 	if ( be == NULL ) {
 #ifdef NEW_LOGGING
diff --git a/servers/slapd/backend.c b/servers/slapd/backend.c
index d199d8486d..1162fa5a9a 100644
--- a/servers/slapd/backend.c
+++ b/servers/slapd/backend.c
@@ -101,7 +101,6 @@ static BackendInfo binfo[] = {
 #if defined(SLAPD_PRIVATE) && !defined(SLAPD_PRIVATE_DYNAMIC)
 	{"private",	private_back_initialize},
 #endif
-	{"glue",	glue_back_initialize},
 	{NULL}
 };
 
@@ -516,7 +515,8 @@ be_db_close( void )
 Backend *
 select_backend(
 	const char * dn,
-	int manageDSAit )
+	int manageDSAit,
+	int noSubs )
 {
 	int	i, j, len, dnlen;
 	Backend *be = NULL;
@@ -526,6 +526,10 @@ select_backend(
 		for ( j = 0; backends[i].be_nsuffix != NULL &&
 		    backends[i].be_nsuffix[j] != NULL; j++ )
 		{
+			if ((backends[i].be_glueflags&SLAP_GLUE_SUBORDINATE)&&
+				noSubs)
+			  	continue;
+
 			len = backends[i].be_nsuffix[j]->bv_len;
 
 			if ( len > dnlen ) {
@@ -997,7 +1001,8 @@ backend_group(
 	if( strcmp( target->e_ndn, gr_ndn ) != 0 ) {
 		/* we won't attempt to send it to a different backend */
 		
-		be = select_backend(gr_ndn, 0);
+		be = select_backend(gr_ndn, 0,
+			(be->be_glueflags & SLAP_GLUE_INSTANCE));
 
 		if (be == NULL) {
 			return LDAP_NO_SUCH_OBJECT;
@@ -1055,7 +1060,8 @@ backend_attribute(
 	if( target == NULL || strcmp( target->e_ndn, e_ndn ) != 0 ) {
 		/* we won't attempt to send it to a different backend */
 		
-		be = select_backend(e_ndn, 0);
+		be = select_backend(e_ndn, 0,
+			(be->be_glueflags & SLAP_GLUE_INSTANCE));
 
 		if (be == NULL) {
 			return LDAP_NO_SUCH_OBJECT;
diff --git a/servers/slapd/backglue.c b/servers/slapd/backglue.c
index d228e9cf93..48ec03100b 100644
--- a/servers/slapd/backglue.c
+++ b/servers/slapd/backglue.c
@@ -10,14 +10,12 @@
  * All of the glued backends must share a common suffix. E.g., you
  * can glue o=foo and ou=bar,o=foo but you can't glue o=foo and o=bar.
  *
- * The only configuration items that are needed for this backend are
- * the suffixes, and they should be identical to suffixes of other
- * backends that are being configured. The suffixes must be listed
- * in order from longest to shortest, (most-specific to least-specific)
- * in order for the selection to work. Every backend that is being glued
- * must be fully configured as usual.
+ * This uses the backend structures and routines extensively, but is
+ * not an actual backend of its own. To use it you must add a "subordinate"
+ * keyword to the configuration of other backends. Subordinates will
+ * automatically be connected to their parent backend.
  *
- * The purpose of this backend is to allow you to split a single database
+ * The purpose of these functions is to allow you to split a single database
  * into pieces (for load balancing purposes, whatever) but still be able
  * to treat it as a single database after it's been split. As such, each
  * of the glued backends should have identical rootdn and rootpw.
@@ -42,15 +40,20 @@ typedef struct gluenode {
 } gluenode;
 
 typedef struct glueinfo {
+	BackendDB *be;
 	int nodes;
 	gluenode n[1];
 } glueinfo;
 
+static int glueMode;
+static int glueBack;
+
 /* Just like select_backend, but only for our backends */
 static BackendDB *
 glue_back_select (
 	BackendDB *be,
-	const char *dn
+	const char *dn,
+	int *idx
 )
 {
 	glueinfo *gi = (glueinfo *) be->be_private;
@@ -60,132 +63,107 @@ glue_back_select (
 	bv.bv_len = strlen(dn);
 	bv.bv_val = (char *) dn;
 
-	for (i = 0; be->be_nsuffix[i]; i++) {
-		if (dn_issuffixbv (&bv, be->be_nsuffix[i]))
+	for (i = 0; i<gi->nodes; i++) {
+		if (dn_issuffixbv (&bv, gi->n[i].be->be_nsuffix[0])) {
+			if (idx)
+				*idx = i;
 			return gi->n[i].be;
+		}
 	}
-	return NULL;
+	return be;
 }
 
+/* This function will only be called in tool mode */
 static int
-glue_back_db_open (
-	BackendDB *be
+glue_back_open (
+	BackendInfo *bi
 )
 {
-	glueinfo *gi;
-	int i, j, k;
-	int ok;
-
-	/*
-	 * Done already? 
-	 */
-	if (be->be_private)
-		return 0;
+	int rc = 0;
+	static int glueOpened = 0;
 
-	for (i = 0; be->be_nsuffix[i]; i++);
+	if (glueOpened) return 0;
 
-	gi = (struct glueinfo *) ch_calloc (1, sizeof (glueinfo) +
-		(i-1) * sizeof (gluenode) );
+	glueOpened = 1;
 
-	be->be_private = gi;
+	/* If we were invoked in tool mode, open all the underlying backends */
+	if (slapMode & SLAP_TOOL_MODE) {
+		rc = backend_startup (NULL);
+	} /* other case is impossible */
+	return rc;
+}
 
-	if (!gi)
-		return 1;
+/* This function will only be called in tool mode */
+static int
+glue_back_close (
+	BackendInfo *bi
+)
+{
+	static int glueClosed = 0;
+	int rc;
 
-	gi->nodes = i;
-	be->be_glueflags = SLAP_GLUE_INSTANCE;
+	if (glueClosed) return 0;
 
-	/*
-	 * For each of our suffixes, find the real backend that handles this 
-	 * suffix. 
-	 */
-	for (i = 0; be->be_nsuffix[i]; i++) {
-		for (j = 0; j < nbackends; j++) {
-			if (be == &backends[j])
-				continue;
-			ok = 0;
-			for (k = 0; backends[j].be_nsuffix &&
-			     backends[j].be_nsuffix[k]; k++) {
-				if (be->be_nsuffix[i]->bv_len !=
-				    backends[j].be_nsuffix[k]->bv_len)
-					continue;
-				if (!strcmp (backends[j].be_nsuffix[k]->bv_val,
-					     be->be_nsuffix[i]->bv_val)) {
-					ok = 1;
-					break;
-				}
-			}
-			if (ok) {
-				gi->n[i].be = &backends[j];
-				gi->n[i].pdn = dn_parent (NULL,
-						 be->be_nsuffix[i]->bv_val);
-				if (i < gi->nodes - 1)
-					gi->n[i].be->be_glueflags =
-						SLAP_GLUE_SUBORDINATE;
-				break;
-			}
-		}
-	}
+	glueClosed = 1;
 
-	/* If we were invoked in tool mode, open all the underlying backends */
 	if (slapMode & SLAP_TOOL_MODE) {
-		for (i = 0; be->be_nsuffix[i]; i++) {
-			backend_startup (gi->n[i].be);
-		}
+		rc = backend_shutdown (NULL);
 	}
-	return 0;
+	return rc;
 }
 
 static int
-glue_back_db_close (
+glue_back_db_open (
 	BackendDB *be
 )
 {
-	glueinfo *gi = (glueinfo *) be->be_private;
+	glueinfo *gi = (glueinfo *)be->be_private;
+	static int glueOpened = 0;
+	int rc = 0;
 
-	if (slapMode & SLAP_TOOL_MODE) {
-		int i;
-		for (i = 0; be->be_nsuffix[i]; i++) {
-			backend_shutdown (gi->n[i].be);
-		}
-	}
-	return 0;
+	if (glueOpened) return 0;
+
+	glueOpened = 1;
+
+	gi->be->be_acl = be->be_acl;
+
+	if (gi->be->bd_info->bi_db_open)
+		rc = gi->be->bd_info->bi_db_open(gi->be);
+
+	return rc;
 }
-int
-glue_back_db_destroy (
+
+static int
+glue_back_db_close (
 	BackendDB *be
 )
 {
-	free (be->be_private);
+	glueinfo *gi = (glueinfo *)be->be_private;
+	static int glueClosed = 0;
+
+	if (glueClosed) return 0;
+
+	glueClosed = 1;
+
+	/* Close the master */
+	if (gi->be->bd_info->bi_db_close)
+		gi->be->bd_info->bi_db_close( gi->be );
+
 	return 0;
 }
 
 int
-glue_back_bind (
-	BackendDB *b0,
-	Connection *conn,
-	Operation *op,
-	const char *dn,
-	const char *ndn,
-	int method,
-	struct berval *cred,
-	char **edn
+glue_back_db_destroy (
+	BackendDB *be
 )
 {
-	BackendDB *be;
-	int rc;
-
-	be = glue_back_select (b0, ndn);
+	glueinfo *gi = (glueinfo *)be->be_private;
 
-	if (be && be->be_bind) {
-		conn->c_authz_backend = be;
-		rc = be->be_bind (be, conn, op, dn, ndn, method, cred, edn);
-	} else {
-		rc = LDAP_UNWILLING_TO_PERFORM;
-		send_ldap_result (conn, op, rc, NULL, "No bind target found",
-				  NULL, NULL);
-	}
-	return rc;
+	if (gi->be->bd_info->bi_db_destroy)
+		gi->be->bd_info->bi_db_destroy( gi->be );
+	free (gi->be);
+	free (gi);
+	return 0;
 }
 
 typedef struct glue_state {
@@ -289,7 +267,7 @@ glue_back_search (
 	int attrsonly
 )
 {
-	glueinfo *gi = (glueinfo *) b0->be_private;
+	glueinfo *gi = (glueinfo *)b0->be_private;
 	BackendDB *be;
 	int i, rc, t2limit = 0, s2limit = 0;
 	long stoptime = 0;
@@ -302,7 +280,7 @@ glue_back_search (
 
 	switch (scope) {
 	case LDAP_SCOPE_BASE:
-		be = glue_back_select (b0, ndn);
+		be = glue_back_select (b0, ndn, NULL);
 
 		if (be && be->be_search) {
 			rc = be->be_search (be, conn, op, dn, ndn, scope,
@@ -353,20 +331,20 @@ glue_back_search (
 			if (scope == LDAP_SCOPE_ONELEVEL && 
 				!strcmp (gi->n[i].pdn, ndn)) {
 				rc = be->be_search (be, conn, op,
-						    b0->be_suffix[i],
-						    b0->be_nsuffix[i]->bv_val,
+						    be->be_suffix[0],
+						    be->be_nsuffix[0]->bv_val,
 						    LDAP_SCOPE_BASE, deref,
 					s2limit, t2limit, filter, filterstr,
 						    attrs, attrsonly);
 			} else if (scope == LDAP_SCOPE_SUBTREE &&
-				dn_issuffixbv (b0->be_nsuffix[i], &bv)) {
+				dn_issuffixbv (be->be_nsuffix[0], &bv)) {
 				rc = be->be_search (be, conn, op,
-						    b0->be_suffix[i],
-						    b0->be_nsuffix[i]->bv_val,
+						    be->be_suffix[0],
+						    be->be_nsuffix[0]->bv_val,
 						    scope, deref,
 					s2limit, t2limit, filter, filterstr,
 						    attrs, attrsonly);
-			} else if (dn_issuffixbv (&bv, b0->be_nsuffix[i])) {
+			} else if (dn_issuffixbv (&bv, be->be_nsuffix[0])) {
 				rc = be->be_search (be, conn, op,
 						    dn, ndn, scope, deref,
 					s2limit, t2limit, filter, filterstr,
@@ -389,6 +367,34 @@ done:
 	return rc;
 }
 
+int
+glue_back_bind (
+	BackendDB *b0,
+	Connection *conn,
+	Operation *op,
+	const char *dn,
+	const char *ndn,
+	int method,
+	struct berval *cred,
+	char **edn
+)
+{
+	BackendDB *be;
+	int rc;
+ 
+	be = glue_back_select (b0, ndn, NULL);
+
+	if (be && be->be_bind) {
+		conn->c_authz_backend = be;
+		rc = be->be_bind (be, conn, op, dn, ndn, method, cred, edn);
+	} else {
+		rc = LDAP_UNWILLING_TO_PERFORM;
+		send_ldap_result (conn, op, rc, NULL, "No bind target found",
+				  NULL, NULL);
+	}
+	return rc;
+}
+
 int
 glue_back_compare (
 	BackendDB *b0,
@@ -402,7 +408,7 @@ glue_back_compare (
 	BackendDB *be;
 	int rc;
 
-	be = glue_back_select (b0, ndn);
+	be = glue_back_select (b0, ndn, NULL);
 
 	if (be && be->be_compare) {
 		rc = be->be_compare (be, conn, op, dn, ndn, ava);
@@ -427,7 +433,7 @@ glue_back_modify (
 	BackendDB *be;
 	int rc;
 
-	be = glue_back_select (b0, ndn);
+	be = glue_back_select (b0, ndn, NULL);
 
 	if (be && be->be_modify) {
 		rc = be->be_modify (be, conn, op, dn, ndn, mod);
@@ -454,7 +460,7 @@ glue_back_modrdn (
 	BackendDB *be;
 	int rc;
 
-	be = glue_back_select (b0, ndn);
+	be = glue_back_select (b0, ndn, NULL);
 
 	if (be && be->be_modrdn) {
 		rc = be->be_modrdn (be, conn, op, dn, ndn, newrdn, del, newsup);
@@ -477,7 +483,7 @@ glue_back_add (
 	BackendDB *be;
 	int rc;
 
-	be = glue_back_select (b0, e->e_ndn);
+	be = glue_back_select (b0, e->e_ndn, NULL);
 
 	if (be && be->be_add) {
 		rc = be->be_add (be, conn, op, e);
@@ -501,7 +507,7 @@ glue_back_delete (
 	BackendDB *be;
 	int rc;
 
-	be = glue_back_select (b0, ndn);
+	be = glue_back_select (b0, ndn, NULL);
 
 	if (be && be->be_delete) {
 		rc = be->be_delete (be, conn, op, dn, ndn);
@@ -525,7 +531,7 @@ glue_back_release_rw (
 	BackendDB *be;
 	int rc;
 
-	be = glue_back_select (b0, e->e_ndn);
+	be = glue_back_select (b0, e->e_ndn, NULL);
 
 	if (be && be->be_release) {
 		rc = be->be_release (be, conn, op, e, rw);
@@ -551,7 +557,7 @@ glue_back_group (
 	BackendDB *be;
 	int rc;
 
-	be = glue_back_select (b0, ndn);
+	be = glue_back_select (b0, ndn, NULL);
 
 	if (be && be->be_group) {
 		rc = be->be_group (be, conn, op, target, ndn, ondn, oc, ad);
@@ -575,7 +581,7 @@ glue_back_attribute (
 	BackendDB *be;
 	int rc;
 
-	be = glue_back_select (b0, ndn);
+	be = glue_back_select (b0, ndn, NULL);
 
 	if (be && be->be_attribute) {
 		rc = be->be_attribute (be, conn, op, target, ndn, ad, vals);
@@ -598,7 +604,7 @@ glue_back_referrals (
 	BackendDB *be;
 	int rc;
 
-	be = glue_back_select (b0, ndn);
+	be = glue_back_select (b0, ndn, NULL);
 
 	if (be && be->be_chk_referrals) {
 		rc = be->be_chk_referrals (be, conn, op, dn, ndn, text);
@@ -608,10 +614,6 @@ glue_back_referrals (
 	return rc;
 }
 
-static int glueMode;
-static int glueBack;
-
-int
 glue_tool_entry_open (
 	BackendDB *b0,
 	int mode
@@ -716,31 +718,25 @@ glue_tool_entry_put (
 	BackendDB *be;
 	int i, rc;
 
-	be = glue_back_select (b0, e->e_ndn);
+	be = glue_back_select (b0, e->e_ndn, &i);
 	if (!be->be_entry_put)
 		return NOID;
 
-	i = glueBack;
-	if (i < 0) {
+	if (glueBack < 0) {
 		rc = be->be_entry_open (be, glueMode);
 		if (rc != 0)
 			return NOID;
-		glueBack = i;
-	} else if (be != gi->n[i].be) {
+	} else if (i != glueBack) {
 		/* If this entry belongs in a different branch than the
 		 * previous one, close the current database and open the
 		 * new one.
 		 */
-		gi->n[i].be->be_entry_close (gi->n[i].be);
-		glueBack = -1;
-		for (i = 0; b0->be_nsuffix[i]; i++)
-			if (gi->n[i].be == be)
-				break;
+		gi->n[glueBack].be->be_entry_close (gi->n[glueBack].be);
 		rc = be->be_entry_open (be, glueMode);
 		if (rc != 0)
 			return NOID;
-		glueBack = i;
 	}
+	glueBack = i;
 	return be->be_entry_put (be, e);
 }
 
@@ -774,53 +770,108 @@ glue_tool_sync (
 	return 0;
 }
 
+extern int num_subs;	/* config.c */
+
 int
-glue_back_initialize (
-	BackendInfo *bi
-)
+glue_sub_init( )
 {
-	bi->bi_open = 0;
-	bi->bi_config = 0;
-	bi->bi_close = 0;
-	bi->bi_destroy = 0;
-
-	bi->bi_db_init = 0;
-	bi->bi_db_config = 0;
-	bi->bi_db_open = glue_back_db_open;
-	bi->bi_db_close = glue_back_db_close;
-	bi->bi_db_destroy = glue_back_db_destroy;
-
-	bi->bi_op_bind = glue_back_bind;
-	bi->bi_op_unbind = 0;
-	bi->bi_op_search = glue_back_search;
-	bi->bi_op_compare = glue_back_compare;
-	bi->bi_op_modify = glue_back_modify;
-	bi->bi_op_modrdn = glue_back_modrdn;
-	bi->bi_op_add = glue_back_add;
-	bi->bi_op_delete = glue_back_delete;
-	bi->bi_op_abandon = 0;
-
-	bi->bi_extended = 0;
-
-	bi->bi_entry_release_rw = glue_back_release_rw;
-	bi->bi_acl_group = glue_back_group;
-	bi->bi_acl_attribute = glue_back_attribute;
-	bi->bi_chk_referrals = glue_back_referrals;
-
-	/*
-	 * hooks for slap tools
-	 */
-	bi->bi_tool_entry_open = glue_tool_entry_open;
-	bi->bi_tool_entry_close = glue_tool_entry_close;
-	bi->bi_tool_entry_first = glue_tool_entry_first;
-	bi->bi_tool_entry_next = glue_tool_entry_next;
-	bi->bi_tool_entry_get = glue_tool_entry_get;
-	bi->bi_tool_entry_put = glue_tool_entry_put;
-	bi->bi_tool_entry_reindex = glue_tool_entry_reindex;
-	bi->bi_tool_sync = glue_tool_sync;
-
-	bi->bi_connection_init = 0;
-	bi->bi_connection_destroy = 0;
+	int i, j, k;
+	int cont = num_subs;
+	BackendDB *b1, *be;
+	BackendInfo *bi;
+	glueinfo *gi;
 
-	return 0;
+	/* While there are subordinate backends, search backwards through the
+	 * backends and connect them to their superior.
+	 */
+	for (i = nBackendDB - 1; cont && i>=0; i--) {
+		if (backendDB[i].be_glueflags & SLAP_GLUE_SUBORDINATE) {
+			/* The last database cannot be a subordinate of noone */
+			if (i == nBackendDB - 1)
+				backendDB[i].be_glueflags ^= SLAP_GLUE_SUBORDINATE;
+			continue;
+		}
+		b1 = &backendDB[i];
+		gi = NULL;
+		for (j = i-1; j>=0; j--) {
+			if (!(backendDB[j].be_glueflags & SLAP_GLUE_SUBORDINATE))
+				continue;
+			/* We will only link it once */
+			if (backendDB[j].be_glueflags & SLAP_GLUE_LINKED)
+				continue;
+			if (!dn_issuffixbv(backendDB[j].be_nsuffix[0],
+				backendDB[i].be_nsuffix[0]))
+				continue;
+			be = &backendDB[j];
+			cont--;
+			be->be_glueflags |= SLAP_GLUE_LINKED;
+			if (gi == NULL) {
+				/* We create a copy of the superior's be
+				 * structure, pointing to all of its original
+				 * information. Then we replace elements of
+				 * the superior's info with our own. The copy
+				 * is used whenever we have operations to pass
+				 * down to the real database.
+				 */
+				b1->be_glueflags |= SLAP_GLUE_INSTANCE;
+				gi = (glueinfo *)ch_malloc(sizeof(glueinfo));
+				gi->be = (BackendDB *)ch_malloc(sizeof(BackendDB) + sizeof(BackendInfo));
+				bi = (BackendInfo *)(gi->be+1);
+				*gi->be = *b1;
+				gi->nodes = 0;
+				*bi = *b1->bd_info;
+				bi->bi_open = glue_back_open;
+				bi->bi_close = glue_back_close;
+				bi->bi_db_open = glue_back_db_open;
+				bi->bi_db_close = glue_back_db_close;
+				bi->bi_db_destroy = glue_back_db_destroy;
+
+				bi->bi_op_bind = glue_back_bind;
+				bi->bi_op_search = glue_back_search;
+				bi->bi_op_compare = glue_back_compare;
+				bi->bi_op_modify = glue_back_modify;
+				bi->bi_op_modrdn = glue_back_modrdn;
+				bi->bi_op_add = glue_back_add;
+				bi->bi_op_delete = glue_back_delete;
+
+				bi->bi_entry_release_rw = glue_back_release_rw;
+				bi->bi_acl_group = glue_back_group;
+				bi->bi_acl_attribute = glue_back_attribute;
+				bi->bi_chk_referrals = glue_back_referrals;
+
+				/*
+				 * hooks for slap tools
+				 */
+				bi->bi_tool_entry_open = glue_tool_entry_open;
+				bi->bi_tool_entry_close = glue_tool_entry_close;
+				bi->bi_tool_entry_first = glue_tool_entry_first;
+				bi->bi_tool_entry_next = glue_tool_entry_next;
+				bi->bi_tool_entry_get = glue_tool_entry_get;
+				bi->bi_tool_entry_put = glue_tool_entry_put;
+				bi->bi_tool_entry_reindex = glue_tool_entry_reindex;
+				bi->bi_tool_sync = glue_tool_sync;
+			} else {
+				gi = (glueinfo *)ch_realloc(gi,
+					sizeof(glueinfo) +
+					gi->nodes * sizeof(gluenode));
+			}
+			gi->n[gi->nodes].be = be;
+			gi->n[gi->nodes].pdn = dn_parent(NULL,
+				be->be_nsuffix[0]->bv_val);
+			gi->nodes++;
+		}
+		if (gi) {
+			/* One more node for the master */
+			gi = (glueinfo *)ch_realloc(gi,
+				sizeof(glueinfo) + gi->nodes * sizeof(gluenode));
+			gi->n[gi->nodes].be = gi->be;
+			gi->n[gi->nodes].pdn = dn_parent(NULL,
+				b1->be_nsuffix[0]->bv_val);
+			gi->nodes++;
+			b1->be_private = gi;
+			b1->bd_info = bi;
+		}
+	}
+	/* If there are any unresolved subordinates left, something is wrong */
+	return cont;
 }
diff --git a/servers/slapd/bind.c b/servers/slapd/bind.c
index f91f65bbfb..1de3d7a72b 100644
--- a/servers/slapd/bind.c
+++ b/servers/slapd/bind.c
@@ -432,7 +432,7 @@ do_bind(
 	 * if we don't hold it.
 	 */
 
-	if ( (be = select_backend( ndn, 0 )) == NULL ) {
+	if ( (be = select_backend( ndn, 0, 0 )) == NULL ) {
 		if ( default_referral ) {
 			struct berval **ref = referral_rewrite( default_referral,
 				NULL, dn, LDAP_SCOPE_DEFAULT );
diff --git a/servers/slapd/compare.c b/servers/slapd/compare.c
index f7d81050ac..b3ccf30a71 100644
--- a/servers/slapd/compare.c
+++ b/servers/slapd/compare.c
@@ -222,7 +222,7 @@ do_compare(
 	 * appropriate one, or send a referral to our "referral server"
 	 * if we don't hold it.
 	 */
-	if ( (be = select_backend( ndn, manageDSAit )) == NULL ) {
+	if ( (be = select_backend( ndn, manageDSAit, 0 )) == NULL ) {
 		struct berval **ref = referral_rewrite( default_referral,
 			NULL, dn, LDAP_SCOPE_DEFAULT );
 
diff --git a/servers/slapd/config.c b/servers/slapd/config.c
index 20386a9afe..92c3b44dba 100644
--- a/servers/slapd/config.c
+++ b/servers/slapd/config.c
@@ -48,6 +48,7 @@ char		*ldap_srvtab = "";
 char		*default_passwd_hash;
 char		*default_search_base = NULL;
 char		*default_search_nbase = NULL;
+int		num_subs = 0;
 
 ber_len_t sockbuf_max_incoming = SLAP_SB_MAX_INCOMING_DEFAULT;
 ber_len_t sockbuf_max_incoming_auth= SLAP_SB_MAX_INCOMING_AUTH;
@@ -824,6 +825,23 @@ read_config( const char *fname )
 				return( 1 );
 			}
 
+		/* mark this as a subordinate database */
+		} else if ( strcasecmp( cargv[0], "subordinate" ) == 0 ) {
+			if ( be == NULL ) {
+#ifdef NEW_LOGGING
+				LDAP_LOG(( "config", LDAP_LEVEL_INFO,
+					   "%s: line %d: subordinate keyword must appear inside a database "
+					   "definition (ignored).\n", fname, lineno ));
+#else
+				Debug( LDAP_DEBUG_ANY,
+"%s: line %d: suffix line must appear inside a database definition (ignored)\n",
+				    fname, lineno, 0 );
+#endif
+			} else {
+				be->be_glueflags |= SLAP_GLUE_SUBORDINATE;
+				num_subs++;
+			}
+
 		/* set database suffix */
 		} else if ( strcasecmp( cargv[0], "suffix" ) == 0 ) {
 			Backend *tmp_be;
@@ -877,7 +895,7 @@ read_config( const char *fname )
 				return( 1 );
 #endif /* SLAPD_MONITOR_DN */
 
-			} else if ( ( tmp_be = select_backend( cargv[1], 0 ) ) == be ) {
+			} else if ( ( tmp_be = select_backend( cargv[1], 0, 0 ) ) == be ) {
 #ifdef NEW_LOGGING
 				LDAP_LOG(( "config", LDAP_LEVEL_INFO,
 					   "%s: line %d: suffix already served by this backend "
@@ -1008,7 +1026,7 @@ read_config( const char *fname )
 					fname, lineno, 0 );
 #endif
 
-			} else if ( (tmp_be = select_backend( cargv[1], 0 )) != NULL ) {
+			} else if ( (tmp_be = select_backend( cargv[1], 0, 0 )) != NULL ) {
 #ifdef NEW_LOGGING
 				LDAP_LOG(( "config", LDAP_LEVEL_INFO,
 					   "%s: line %d: suffixAlias served by a preceeding "
@@ -1022,7 +1040,7 @@ read_config( const char *fname )
 #endif
 
 
-			} else if ( (tmp_be = select_backend( cargv[2], 0 )) != NULL ) {
+			} else if ( (tmp_be = select_backend( cargv[2], 0, 0 )) != NULL ) {
 #ifdef NEW_LOGGING
 				LDAP_LOG(( "config", LDAP_LEVEL_INFO,
 					   "%s: line %d: suffixAlias derefs to a different backend "
diff --git a/servers/slapd/delete.c b/servers/slapd/delete.c
index 492d44c2bd..bbda5a3f90 100644
--- a/servers/slapd/delete.c
+++ b/servers/slapd/delete.c
@@ -124,7 +124,7 @@ do_delete(
 	 * appropriate one, or send a referral to our "referral server"
 	 * if we don't hold it.
 	 */
-	if ( (be = select_backend( ndn, manageDSAit )) == NULL ) {
+	if ( (be = select_backend( ndn, manageDSAit, 0 )) == NULL ) {
 		struct berval **ref = referral_rewrite( default_referral,
 			NULL, dn, LDAP_SCOPE_DEFAULT );
 
diff --git a/servers/slapd/main.c b/servers/slapd/main.c
index ccb6c0e12c..b71bb99d21 100644
--- a/servers/slapd/main.c
+++ b/servers/slapd/main.c
@@ -381,6 +381,18 @@ int main( int argc, char **argv )
 		goto destroy;
 	}
 
+	if ( glue_sub_init( ) != 0 ) {
+#ifdef NEW_LOGGING
+		LDAP_LOG(( "operation", LDAP_LEVEL_CRIT,
+			   "main: subordinate config error\n"));
+#else
+		Debug( LDAP_DEBUG_ANY,
+		    "subordinate config error\n",
+		    0, 0, 0 );
+#endif
+		goto destroy;
+	}
+
 	if ( schema_prep( ) != 0 ) {
 #ifdef NEW_LOGGING
 		LDAP_LOG(( "operation", LDAP_LEVEL_CRIT,
diff --git a/servers/slapd/modify.c b/servers/slapd/modify.c
index 081e484b68..6c882c7ab5 100644
--- a/servers/slapd/modify.c
+++ b/servers/slapd/modify.c
@@ -280,7 +280,7 @@ do_modify(
 	 * appropriate one, or send a referral to our "referral server"
 	 * if we don't hold it.
 	 */
-	if ( (be = select_backend( ndn, manageDSAit )) == NULL ) {
+	if ( (be = select_backend( ndn, manageDSAit, 0 )) == NULL ) {
 		struct berval **ref = referral_rewrite( default_referral,
 			NULL, dn, LDAP_SCOPE_DEFAULT );
 
diff --git a/servers/slapd/modrdn.c b/servers/slapd/modrdn.c
index 1d57bd875b..861b2142b7 100644
--- a/servers/slapd/modrdn.c
+++ b/servers/slapd/modrdn.c
@@ -249,7 +249,7 @@ do_modrdn(
 	 * appropriate one, or send a referral to our "referral server"
 	 * if we don't hold it.
 	 */
-	if ( (be = select_backend( ndn, manageDSAit )) == NULL ) {
+	if ( (be = select_backend( ndn, manageDSAit, 0 )) == NULL ) {
 		struct berval **ref = referral_rewrite( default_referral,
 			NULL, dn, LDAP_SCOPE_DEFAULT );
 
@@ -278,7 +278,7 @@ do_modrdn(
 	 * the same backend, otherwise we return an error.
 	 */
 	if( newSuperior != NULL ) {
-		newSuperior_be = select_backend( nnewSuperior, 0 );
+		newSuperior_be = select_backend( nnewSuperior, 0, 0 );
 
 		if ( newSuperior_be != be ) {
 			/* newSuperior is in same backend */
diff --git a/servers/slapd/proto-slap.h b/servers/slapd/proto-slap.h
index 0b4b737c2e..5571ec2fb6 100644
--- a/servers/slapd/proto-slap.h
+++ b/servers/slapd/proto-slap.h
@@ -152,7 +152,8 @@ LDAP_SLAPD_F (BackendDB *) backend_db_init LDAP_P(( const char *type ));
 
 LDAP_SLAPD_F (BackendDB *) select_backend LDAP_P((
 	const char * dn,
-	int manageDSAit ));
+	int manageDSAit,
+	int noSubordinates ));
 
 LDAP_SLAPD_F (int) be_issuffix LDAP_P(( Backend *be, const char *suffix ));
 LDAP_SLAPD_F (int) be_isroot LDAP_P(( Backend *be, const char *ndn ));
diff --git a/servers/slapd/repl.c b/servers/slapd/repl.c
index 42f4a090b1..92b1f44275 100644
--- a/servers/slapd/repl.c
+++ b/servers/slapd/repl.c
@@ -57,7 +57,7 @@ add_replica_suffix(
 	int 	rc = 0;
 
 	if ( dn_normalize( nsuffix ) != NULL ) {
-		if ( select_backend( nsuffix, 0 ) == be ) {
+		if ( select_backend( nsuffix, 0, 0 ) == be ) {
 			charray_add( &be->be_replica[nr]->ri_nsuffix, nsuffix );
 		} else {
 			rc = 1;
diff --git a/servers/slapd/root_dse.c b/servers/slapd/root_dse.c
index f5e2e95fd8..61de132c3a 100644
--- a/servers/slapd/root_dse.c
+++ b/servers/slapd/root_dse.c
@@ -70,7 +70,7 @@ root_dse_info(
 	attr_merge( e, ad_objectClass, vals );
 
 	for ( i = 0; i < nbackends; i++ ) {
-		if ( backends[i].be_glueflags )
+		if ( backends[i].be_glueflags & SLAP_GLUE_SUBORDINATE )
 			continue;
 		for ( j = 0; backends[i].be_suffix[j] != NULL; j++ ) {
 			val.bv_val = backends[i].be_suffix[j];
diff --git a/servers/slapd/saslauthz.c b/servers/slapd/saslauthz.c
index 280e50ad15..a487139a47 100644
--- a/servers/slapd/saslauthz.c
+++ b/servers/slapd/saslauthz.c
@@ -342,7 +342,7 @@ char *slap_sasl2dn( char *saslname )
 #endif
 
 
-	be = select_backend( searchbase, 0 );
+	be = select_backend( searchbase, 0, 1 );
 	if(( be == NULL ) || ( be->be_search == NULL))
 		goto FINISHED;
 	searchbase = suffix_alias( be, searchbase );
@@ -463,7 +463,7 @@ int slap_sasl_match( char *rule, char *assertDN, char *authc )
 #endif
 
 
-	be = select_backend( searchbase, 0 );
+	be = select_backend( searchbase, 0, 1 );
 	if(( be == NULL ) || ( be->be_search == NULL)) {
 		rc = LDAP_INAPPROPRIATE_AUTH;
 		goto CONCLUDED;
diff --git a/servers/slapd/search.c b/servers/slapd/search.c
index 086e924137..0f9af2b4b2 100644
--- a/servers/slapd/search.c
+++ b/servers/slapd/search.c
@@ -267,7 +267,7 @@ do_search(
 	 * appropriate one, or send a referral to our "referral server"
 	 * if we don't hold it.
 	 */
-	if ( (be = select_backend( nbase, manageDSAit )) == NULL ) {
+	if ( (be = select_backend( nbase, manageDSAit, 1 )) == NULL ) {
 		struct berval **ref = referral_rewrite( default_referral,
 			NULL, base, scope );
 
diff --git a/servers/slapd/slap.h b/servers/slapd/slap.h
index d509d068e0..0cdb930dea 100644
--- a/servers/slapd/slap.h
+++ b/servers/slapd/slap.h
@@ -997,8 +997,9 @@ struct slap_backend_db {
 	struct berval **be_update_refs;	/* where to refer modifying clients to */
 	int	be_lastmod;	/* keep track of lastmodified{by,time}	   */
 
-#define	SLAP_GLUE_SUBORDINATE	0x01	/* child of a glue hierarchy */
-#define	SLAP_GLUE_INSTANCE	0x02	/* a glue backend */
+#define	SLAP_GLUE_INSTANCE	0x01	/* a glue backend */
+#define	SLAP_GLUE_SUBORDINATE	0x02	/* child of a glue hierarchy */
+#define	SLAP_GLUE_LINKED	0x04	/* child is connected to parent */
 
 	int	be_glueflags;	/* */
 
diff --git a/servers/slapd/tools/slapadd.c b/servers/slapd/tools/slapadd.c
index c32d593ae4..65923fcae5 100644
--- a/servers/slapd/tools/slapadd.c
+++ b/servers/slapd/tools/slapadd.c
@@ -81,7 +81,7 @@ main( int argc, char **argv )
 		}
 
 		/* check backend */
-		if( select_backend( e->e_ndn, is_entry_referral(e) ) != be )
+		if( select_backend( e->e_ndn, is_entry_referral(e), nosubs ) != be )
 		{
 			fprintf( stderr, "%s: database (%s) not configured to "
 				"hold dn=\"%s\" (line=%d)\n",
diff --git a/servers/slapd/tools/slapcommon.c b/servers/slapd/tools/slapcommon.c
index 9c583c964d..3143550611 100644
--- a/servers/slapd/tools/slapcommon.c
+++ b/servers/slapd/tools/slapcommon.c
@@ -24,6 +24,7 @@ char	*conffile	= SLAPD_DEFAULT_CONFIGFILE;
 int		truncatemode = 0;
 int		verbose		= 0;
 int		continuemode = 0;
+int	nosubs		= 0;
 
 char	*ldiffile	= NULL;
 FILE	*ldiffp		= NULL;
@@ -195,6 +196,13 @@ slap_tool_init(
 		exit( EXIT_FAILURE );
 	}
 
+	rc = glue_sub_init();
+
+	if (rc != 0 ) {
+		fprintf( stderr, "Subordinate configuration error\n" );
+		exit( EXIT_FAILURE );
+	}
+
 	rc = schema_prep();
 
 	if (rc != 0 ) {
@@ -211,7 +219,7 @@ slap_tool_init(
 			exit( EXIT_FAILURE );
 		}
 
-		be = select_backend( tbase, 0 );
+		be = select_backend( tbase, 0, 0 );
 		free( tbase );
 
 		if( be == NULL ) {
@@ -219,9 +227,21 @@ slap_tool_init(
 				progname, base );
 			exit( EXIT_FAILURE );
 		}
+		/* If the named base is a glue master, operate on the
+		 * entire context
+		 */
+		if (be->be_glueflags & SLAP_GLUE_INSTANCE)
+			nosubs = 1;
 
 	} else if ( dbnum == -1 ) {
 		be = &backends[dbnum=0];
+		/* If just doing the first by default and it is a
+		 * glue subordinate, find the master.
+		 */
+		while (be->be_glueflags & SLAP_GLUE_SUBORDINATE) {
+			nosubs = 1;
+			be++;
+		}
 
 	} else if ( dbnum < 0 || dbnum > (nbackends-1) ) {
 		fprintf( stderr,
diff --git a/servers/slapd/tools/slapcommon.h b/servers/slapd/tools/slapcommon.h
index ca8dcf5207..600418b0c4 100644
--- a/servers/slapd/tools/slapcommon.h
+++ b/servers/slapd/tools/slapcommon.h
@@ -25,6 +25,7 @@ extern	Backend *be;
 extern	int		appendmode;
 extern	int		verbose;
 extern	int		continuemode;
+extern	int	nosubs;
 
 extern	char	*ldiffile;
 extern	FILE	*ldiffp;