Adding upstream version 2.4.57+dfsg.upstream/2.4.57+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 981 insertions, 0 deletions

diff --git a/servers/slapd/back-mdb/dn2id.c b/servers/slapd/back-mdb/dn2id.c
new file mode 100644
index 0000000..25e9fe8
--- /dev/null
+++ b/servers/slapd/back-mdb/dn2id.c
@@ -0,0 +1,981 @@
+/* dn2id.c - routines to deal with the dn2id index */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2000-2021 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>.
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+#include <ac/string.h>
+
+#include "back-mdb.h"
+#include "idl.h"
+#include "lutil.h"
+
+/* Management routines for a hierarchically structured database.
+ *
+ * Instead of a ldbm-style dn2id database, we use a hierarchical one. Each
+ * entry in this database is a struct diskNode, keyed by entryID and with
+ * the data containing the RDN and entryID of the node's children. We use
+ * a B-Tree with sorted duplicates to store all the children of a node under
+ * the same key. Also, the first item under the key contains the entry's own
+ * rdn and the ID of the node's parent, to allow bottom-up tree traversal as
+ * well as top-down. To keep this info first in the list, the high bit of all
+ * subsequent nrdnlen's is always set. This means we can only accomodate
+ * RDNs up to length 32767, but that's fine since full DNs are already
+ * restricted to 8192.
+ *
+ * Also each child node contains a count of the number of entries in
+ * its subtree, appended after its entryID.
+ *
+ * The diskNode is a variable length structure. This definition is not
+ * directly usable for in-memory manipulation.
+ */
+typedef struct diskNode {
+	unsigned char nrdnlen[2];
+	char nrdn[1];
+	char rdn[1];                        /* variable placement */
+	unsigned char entryID[sizeof(ID)];  /* variable placement */
+	/* unsigned char nsubs[sizeof(ID)];	in child nodes only */
+} diskNode;
+
+/* Sort function for the sorted duplicate data items of a dn2id key.
+ * Sorts based on normalized RDN, in length order.
+ */
+int
+mdb_dup_compare(
+	const MDB_val *usrkey,
+	const MDB_val *curkey
+)
+{
+	diskNode *un, *cn;
+	int rc, nrlen;
+
+	un = (diskNode *)usrkey->mv_data;
+	cn = (diskNode *)curkey->mv_data;
+
+	/* data is not aligned, cannot compare directly */
+	rc = un->nrdnlen[0] - cn->nrdnlen[0];
+	if ( rc ) return rc;
+	rc = un->nrdnlen[1] - cn->nrdnlen[1];
+	if ( rc ) return rc;
+
+	nrlen = ((un->nrdnlen[0] & 0x7f) << 8) | un->nrdnlen[1];
+	return strncmp( un->nrdn, cn->nrdn, nrlen );
+}
+
+/* We add two elements to the DN2ID database - a data item under the parent's
+ * entryID containing the child's RDN and entryID, and an item under the
+ * child's entryID containing the parent's entryID.
+ */
+int
+mdb_dn2id_add(
+	Operation	*op,
+	MDB_cursor	*mcp,
+	MDB_cursor	*mcd,
+	ID pid,
+	ID nsubs,
+	int upsub,
+	Entry		*e )
+{
+	struct mdb_info *mdb = (struct mdb_info *) op->o_bd->be_private;
+	MDB_val		key, data;
+	ID		nid;
+	int		rc, rlen, nrlen;
+	diskNode *d;
+	char *ptr;
+
+	Debug( LDAP_DEBUG_TRACE, "=> mdb_dn2id_add 0x%lx: \"%s\"\n",
+		e->e_id, e->e_ndn ? e->e_ndn : "", 0 );
+
+	nrlen = dn_rdnlen( op->o_bd, &e->e_nname );
+	if (nrlen) {
+		rlen = dn_rdnlen( op->o_bd, &e->e_name );
+	} else {
+		nrlen = e->e_nname.bv_len;
+		rlen = e->e_name.bv_len;
+	}
+
+	d = op->o_tmpalloc(sizeof(diskNode) + rlen + nrlen + sizeof(ID), op->o_tmpmemctx);
+	d->nrdnlen[1] = nrlen & 0xff;
+	d->nrdnlen[0] = (nrlen >> 8) | 0x80;
+	ptr = lutil_strncopy( d->nrdn, e->e_nname.bv_val, nrlen );
+	*ptr++ = '\0';
+	ptr = lutil_strncopy( ptr, e->e_name.bv_val, rlen );
+	*ptr++ = '\0';
+	memcpy( ptr, &e->e_id, sizeof( ID ));
+	ptr += sizeof( ID );
+	memcpy( ptr, &nsubs, sizeof( ID ));
+
+	key.mv_size = sizeof(ID);
+	key.mv_data = &nid;
+
+	nid = pid;
+
+	/* Need to make dummy root node once. Subsequent attempts
+	 * will fail harmlessly.
+	 */
+	if ( pid == 0 ) {
+		diskNode dummy = {{0, 0}, "", "", ""};
+		data.mv_data = &dummy;
+		data.mv_size = sizeof(diskNode);
+
+		mdb_cursor_put( mcp, &key, &data, MDB_NODUPDATA );
+	}
+
+	data.mv_data = d;
+	data.mv_size = sizeof(diskNode) + rlen + nrlen + sizeof( ID );
+
+	/* Add our child node under parent's key */
+	rc = mdb_cursor_put( mcp, &key, &data, MDB_NODUPDATA );
+
+	/* Add our own node */
+	if (rc == 0) {
+		int flag = MDB_NODUPDATA;
+		nid = e->e_id;
+		/* drop subtree count */
+		data.mv_size -= sizeof( ID );
+		ptr -= sizeof( ID );
+		memcpy( ptr, &pid, sizeof( ID ));
+		d->nrdnlen[0] ^= 0x80;
+
+		if ((slapMode & SLAP_TOOL_MODE) || (e->e_id == mdb->mi_nextid))
+			flag |= MDB_APPEND;
+		rc = mdb_cursor_put( mcd, &key, &data, flag );
+	}
+	op->o_tmpfree( d, op->o_tmpmemctx );
+
+	/* Add our subtree count to all superiors */
+	if ( rc == 0 && upsub && pid ) {
+		ID subs;
+		nid = pid;
+		do {
+			/* Get parent's RDN */
+			rc = mdb_cursor_get( mcp, &key, &data, MDB_SET );
+			if ( !rc ) {
+				char *p2;
+				ptr = (char *)data.mv_data + data.mv_size - sizeof( ID );
+				memcpy( &nid, ptr, sizeof( ID ));
+				/* Get parent's node under grandparent */
+				d = data.mv_data;
+				rlen = ( d->nrdnlen[0] << 8 ) | d->nrdnlen[1];
+				p2 = op->o_tmpalloc( rlen + 2, op->o_tmpmemctx );
+				memcpy( p2, data.mv_data, rlen+2 );
+				*p2 ^= 0x80;
+				data.mv_data = p2;
+				rc = mdb_cursor_get( mcp, &key, &data, MDB_GET_BOTH );
+				op->o_tmpfree( p2, op->o_tmpmemctx );
+				if ( !rc ) {
+					/* Get parent's subtree count */
+					ptr = (char *)data.mv_data + data.mv_size - sizeof( ID );
+					memcpy( &subs, ptr, sizeof( ID ));
+					subs += nsubs;
+					p2 = op->o_tmpalloc( data.mv_size, op->o_tmpmemctx );
+					memcpy( p2, data.mv_data, data.mv_size - sizeof( ID ));
+					memcpy( p2+data.mv_size - sizeof( ID ), &subs, sizeof( ID ));
+					data.mv_data = p2;
+					rc = mdb_cursor_put( mcp, &key, &data, MDB_CURRENT );
+					op->o_tmpfree( p2, op->o_tmpmemctx );
+				}
+			}
+			if ( rc )
+				break;
+		} while ( nid );
+	}
+
+	Debug( LDAP_DEBUG_TRACE, "<= mdb_dn2id_add 0x%lx: %d\n", e->e_id, rc, 0 );
+
+	return rc;
+}
+
+/* mc must have been set by mdb_dn2id */
+int
+mdb_dn2id_delete(
+	Operation	*op,
+	MDB_cursor *mc,
+	ID id,
+	ID nsubs )
+{
+	ID nid;
+	char *ptr;
+	int rc;
+
+	Debug( LDAP_DEBUG_TRACE, "=> mdb_dn2id_delete 0x%lx\n",
+		id, 0, 0 );
+
+	/* Delete our ID from the parent's list */
+	rc = mdb_cursor_del( mc, 0 );
+
+	/* Delete our ID from the tree. With sorted duplicates, this
+	 * will leave any child nodes still hanging around. This is OK
+	 * for modrdn, which will add our info back in later.
+	 */
+	if ( rc == 0 ) {
+		MDB_val	key, data;
+		if ( nsubs ) {
+			mdb_cursor_get( mc, &key, NULL, MDB_GET_CURRENT );
+			memcpy( &nid, key.mv_data, sizeof( ID ));
+		}
+		key.mv_size = sizeof(ID);
+		key.mv_data = &id;
+		rc = mdb_cursor_get( mc, &key, &data, MDB_SET );
+		if ( rc == 0 )
+			rc = mdb_cursor_del( mc, 0 );
+	}
+
+	/* Delete our subtree count from all superiors */
+	if ( rc == 0 && nsubs && nid ) {
+		MDB_val key, data;
+		ID subs;
+		key.mv_data = &nid;
+		key.mv_size = sizeof( ID );
+		do {
+			rc = mdb_cursor_get( mc, &key, &data, MDB_SET );
+			if ( !rc ) {
+				char *p2;
+				diskNode *d;
+				int rlen;
+				ptr = (char *)data.mv_data + data.mv_size - sizeof( ID );
+				memcpy( &nid, ptr, sizeof( ID ));
+				/* Get parent's node under grandparent */
+				d = data.mv_data;
+				rlen = ( d->nrdnlen[0] << 8 ) | d->nrdnlen[1];
+				p2 = op->o_tmpalloc( rlen + 2, op->o_tmpmemctx );
+				memcpy( p2, data.mv_data, rlen+2 );
+				*p2 ^= 0x80;
+				data.mv_data = p2;
+				rc = mdb_cursor_get( mc, &key, &data, MDB_GET_BOTH );
+				op->o_tmpfree( p2, op->o_tmpmemctx );
+				if ( !rc ) {
+					/* Get parent's subtree count */
+					ptr = (char *)data.mv_data + data.mv_size - sizeof( ID );
+					memcpy( &subs, ptr, sizeof( ID ));
+					subs -= nsubs;
+					p2 = op->o_tmpalloc( data.mv_size, op->o_tmpmemctx );
+					memcpy( p2, data.mv_data, data.mv_size - sizeof( ID ));
+					memcpy( p2+data.mv_size - sizeof( ID ), &subs, sizeof( ID ));
+					data.mv_data = p2;
+					rc = mdb_cursor_put( mc, &key, &data, MDB_CURRENT );
+					op->o_tmpfree( p2, op->o_tmpmemctx );
+				}
+
+			}
+			if ( rc )
+				break;
+		} while ( nid );
+	}
+
+	Debug( LDAP_DEBUG_TRACE, "<= mdb_dn2id_delete 0x%lx: %d\n", id, rc, 0 );
+	return rc;
+}
+
+/* return last found ID in *id if no match
+ * If mc is provided, it will be left pointing to the RDN's
+ * record under the parent's ID. If nsubs is provided, return
+ * the number of entries in this entry's subtree.
+ */
+int
+mdb_dn2id(
+	Operation	*op,
+	MDB_txn *txn,
+	MDB_cursor	*mc,
+	struct berval	*in,
+	ID	*id,
+	ID	*nsubs,
+	struct berval	*matched,
+	struct berval	*nmatched )
+{
+	struct mdb_info *mdb = (struct mdb_info *) op->o_bd->be_private;
+	MDB_cursor *cursor;
+	MDB_dbi dbi = mdb->mi_dn2id;
+	MDB_val		key, data;
+	int		rc = 0, nrlen;
+	diskNode *d;
+	char	*ptr;
+	char dn[SLAP_LDAPDN_MAXLEN];
+	ID pid, nid;
+	struct berval tmp;
+
+	Debug( LDAP_DEBUG_TRACE, "=> mdb_dn2id(\"%s\")\n", in->bv_val ? in->bv_val : "", 0, 0 );
+
+	if ( matched ) {
+		matched->bv_val = dn + sizeof(dn) - 1;
+		matched->bv_len = 0;
+		*matched->bv_val-- = '\0';
+	}
+	if ( nmatched ) {
+		nmatched->bv_len = 0;
+		nmatched->bv_val = 0;
+	}
+
+	if ( !in->bv_len ) {
+		*id = 0;
+		nid = 0;
+		goto done;
+	}
+
+	tmp = *in;
+
+	if ( op->o_bd->be_nsuffix[0].bv_len ) {
+		nrlen = tmp.bv_len - op->o_bd->be_nsuffix[0].bv_len;
+		tmp.bv_val += nrlen;
+		tmp.bv_len = op->o_bd->be_nsuffix[0].bv_len;
+	} else {
+		for ( ptr = tmp.bv_val + tmp.bv_len - 1; ptr >= tmp.bv_val; ptr-- )
+			if (DN_SEPARATOR(*ptr))
+				break;
+		ptr++;
+		tmp.bv_len -= ptr - tmp.bv_val;
+		tmp.bv_val = ptr;
+	}
+	nid = 0;
+	key.mv_size = sizeof(ID);
+
+	if ( mc ) {
+		cursor = mc;
+	} else {
+		rc = mdb_cursor_open( txn, dbi, &cursor );
+		if ( rc ) goto done;
+	}
+
+	for (;;) {
+		key.mv_data = &pid;
+		pid = nid;
+
+		data.mv_size = sizeof(diskNode) + tmp.bv_len;
+		d = op->o_tmpalloc( data.mv_size, op->o_tmpmemctx );
+		d->nrdnlen[1] = tmp.bv_len & 0xff;
+		d->nrdnlen[0] = (tmp.bv_len >> 8) | 0x80;
+		ptr = lutil_strncopy( d->nrdn, tmp.bv_val, tmp.bv_len );
+		*ptr = '\0';
+		data.mv_data = d;
+		rc = mdb_cursor_get( cursor, &key, &data, MDB_GET_BOTH );
+		op->o_tmpfree( d, op->o_tmpmemctx );
+		if ( rc )
+			break;
+		ptr = (char *) data.mv_data + data.mv_size - 2*sizeof(ID);
+		memcpy( &nid, ptr, sizeof(ID));
+
+		/* grab the non-normalized RDN */
+		if ( matched ) {
+			int rlen;
+			d = data.mv_data;
+			rlen = data.mv_size - sizeof(diskNode) - tmp.bv_len - sizeof(ID);
+			matched->bv_len += rlen;
+			matched->bv_val -= rlen + 1;
+			ptr = lutil_strcopy( matched->bv_val, d->rdn + tmp.bv_len );
+			if ( pid ) {
+				*ptr = ',';
+				matched->bv_len++;
+			}
+		}
+		if ( nmatched ) {
+			nmatched->bv_val = tmp.bv_val;
+		}
+
+		if ( tmp.bv_val > in->bv_val ) {
+			for (ptr = tmp.bv_val - 2; ptr > in->bv_val &&
+				!DN_SEPARATOR(*ptr); ptr--)	/* empty */;
+			if ( ptr >= in->bv_val ) {
+				if (DN_SEPARATOR(*ptr)) ptr++;
+				tmp.bv_len = tmp.bv_val - ptr - 1;
+				tmp.bv_val = ptr;
+			}
+		} else {
+			break;
+		}
+	}
+	*id = nid; 
+	/* return subtree count if requested */
+	if ( !rc && nsubs ) {
+		ptr = (char *)data.mv_data + data.mv_size - sizeof(ID);
+		memcpy( nsubs, ptr, sizeof( ID ));
+	}
+	if ( !mc )
+		mdb_cursor_close( cursor );
+done:
+	if ( matched ) {
+		if ( matched->bv_len ) {
+			ptr = op->o_tmpalloc( matched->bv_len+1, op->o_tmpmemctx );
+			strcpy( ptr, matched->bv_val );
+			matched->bv_val = ptr;
+		} else {
+			if ( BER_BVISEMPTY( &op->o_bd->be_nsuffix[0] ) && !nid ) {
+				ber_dupbv( matched, (struct berval *)&slap_empty_bv );
+			} else {
+				matched->bv_val = NULL;
+			}
+		}
+	}
+	if ( nmatched ) {
+		if ( nmatched->bv_val ) {
+			nmatched->bv_len = in->bv_len - (nmatched->bv_val - in->bv_val);
+		} else {
+			*nmatched = slap_empty_bv;
+		}
+	}
+
+	if( rc != 0 ) {
+		Debug( LDAP_DEBUG_TRACE, "<= mdb_dn2id: get failed: %s (%d)\n",
+			mdb_strerror( rc ), rc, 0 );
+	} else {
+		Debug( LDAP_DEBUG_TRACE, "<= mdb_dn2id: got id=0x%lx\n",
+			nid, 0, 0 );
+	}
+
+	return rc;
+}
+
+/* return IDs from root to parent of DN */
+int
+mdb_dn2sups(
+	Operation	*op,
+	MDB_txn *txn,
+	struct berval	*in,
+	ID	*ids )
+{
+	struct mdb_info *mdb = (struct mdb_info *) op->o_bd->be_private;
+	MDB_cursor *cursor;
+	MDB_dbi dbi = mdb->mi_dn2id;
+	MDB_val		key, data;
+	int		rc = 0, nrlen;
+	diskNode *d;
+	char	*ptr;
+	ID pid, nid;
+	struct berval tmp;
+
+	Debug( LDAP_DEBUG_TRACE, "=> mdb_dn2sups(\"%s\")\n", in->bv_val, 0, 0 );
+
+	if ( !in->bv_len ) {
+		goto done;
+	}
+
+	tmp = *in;
+
+	nrlen = tmp.bv_len - op->o_bd->be_nsuffix[0].bv_len;
+	tmp.bv_val += nrlen;
+	tmp.bv_len = op->o_bd->be_nsuffix[0].bv_len;
+	nid = 0;
+	key.mv_size = sizeof(ID);
+
+	rc = mdb_cursor_open( txn, dbi, &cursor );
+	if ( rc ) goto done;
+
+	for (;;) {
+		key.mv_data = &pid;
+		pid = nid;
+
+		data.mv_size = sizeof(diskNode) + tmp.bv_len;
+		d = op->o_tmpalloc( data.mv_size, op->o_tmpmemctx );
+		d->nrdnlen[1] = tmp.bv_len & 0xff;
+		d->nrdnlen[0] = (tmp.bv_len >> 8) | 0x80;
+		ptr = lutil_strncopy( d->nrdn, tmp.bv_val, tmp.bv_len );
+		*ptr = '\0';
+		data.mv_data = d;
+		rc = mdb_cursor_get( cursor, &key, &data, MDB_GET_BOTH );
+		op->o_tmpfree( d, op->o_tmpmemctx );
+		if ( rc )
+			break;
+		ptr = (char *) data.mv_data + data.mv_size - 2*sizeof(ID);
+		memcpy( &nid, ptr, sizeof(ID));
+
+		if ( pid )
+			mdb_idl_insert( ids, pid );
+
+		if ( tmp.bv_val > in->bv_val ) {
+			for (ptr = tmp.bv_val - 2; ptr > in->bv_val &&
+				!DN_SEPARATOR(*ptr); ptr--)	/* empty */;
+			if ( ptr >= in->bv_val ) {
+				if (DN_SEPARATOR(*ptr)) ptr++;
+				tmp.bv_len = tmp.bv_val - ptr - 1;
+				tmp.bv_val = ptr;
+			}
+		} else {
+			break;
+		}
+	}
+	mdb_cursor_close( cursor );
+done:
+	if( rc != 0 ) {
+		Debug( LDAP_DEBUG_TRACE, "<= mdb_dn2sups: get failed: %s (%d)\n",
+			mdb_strerror( rc ), rc, 0 );
+	}
+
+	return rc;
+}
+
+int
+mdb_dn2id_children(
+	Operation *op,
+	MDB_txn *txn,
+	Entry *e )
+{
+	struct mdb_info *mdb = (struct mdb_info *) op->o_bd->be_private;
+	MDB_dbi dbi = mdb->mi_dn2id;
+	MDB_val		key, data;
+	MDB_cursor	*cursor;
+	int		rc;
+	ID		id;
+
+	key.mv_size = sizeof(ID);
+	key.mv_data = &id;
+	id = e->e_id;
+
+	rc = mdb_cursor_open( txn, dbi, &cursor );
+	if ( rc ) return rc;
+
+	rc = mdb_cursor_get( cursor, &key, &data, MDB_SET );
+	if ( rc == 0 ) {
+		size_t dkids;
+		rc = mdb_cursor_count( cursor, &dkids );
+		if ( rc == 0 ) {
+			if ( dkids < 2 ) rc = MDB_NOTFOUND;
+		}
+	}
+	mdb_cursor_close( cursor );
+	return rc;
+}
+
+int
+mdb_id2name(
+	Operation *op,
+	MDB_txn *txn,
+	MDB_cursor **cursp,
+	ID id,
+	struct berval *name,
+	struct berval *nname )
+{
+	struct mdb_info *mdb = (struct mdb_info *) op->o_bd->be_private;
+	MDB_dbi dbi = mdb->mi_dn2id;
+	MDB_val		key, data;
+	MDB_cursor	*cursor;
+	int		rc, len, nlen;
+	char dn[SLAP_LDAPDN_MAXLEN], ndn[SLAP_LDAPDN_MAXLEN], *ptr;
+	char *dptr, *nptr;
+	diskNode *d;
+
+	key.mv_size = sizeof(ID);
+
+	if ( !*cursp ) {
+		rc = mdb_cursor_open( txn, dbi, cursp );
+		if ( rc ) return rc;
+	}
+	cursor = *cursp;
+
+	len = 0;
+	nlen = 0;
+	dptr = dn;
+	nptr = ndn;
+	while (id) {
+		unsigned int nrlen, rlen;
+		key.mv_data = &id;
+		data.mv_size = 0;
+		data.mv_data = "";
+		rc = mdb_cursor_get( cursor, &key, &data, MDB_SET );
+		if ( rc ) break;
+		ptr = data.mv_data;
+		ptr += data.mv_size - sizeof(ID);
+		memcpy( &id, ptr, sizeof(ID) );
+		d = data.mv_data;
+		nrlen = (d->nrdnlen[0] << 8) | d->nrdnlen[1];
+		rlen = data.mv_size - sizeof(diskNode) - nrlen;
+		assert( nrlen < 1024 && rlen < 1024 );	/* FIXME: Sanity check */
+		if (nptr > ndn) {
+			*nptr++ = ',';
+			*dptr++ = ',';
+		}
+		/* copy name and trailing NUL */
+		memcpy( nptr, d->nrdn, nrlen+1 );
+		memcpy( dptr, d->nrdn+nrlen+1, rlen+1 );
+		nptr += nrlen;
+		dptr += rlen;
+	}
+	if ( rc == 0 ) {
+		name->bv_len = dptr - dn;
+		nname->bv_len = nptr - ndn;
+		name->bv_val = op->o_tmpalloc( name->bv_len + 1, op->o_tmpmemctx );
+		nname->bv_val = op->o_tmpalloc( nname->bv_len + 1, op->o_tmpmemctx );
+		memcpy( name->bv_val, dn, name->bv_len );
+		name->bv_val[name->bv_len] = '\0';
+		memcpy( nname->bv_val, ndn, nname->bv_len );
+		nname->bv_val[nname->bv_len] = '\0';
+	}
+	return rc;
+}
+
+/* Find each id in ids that is a child of base and move it to res.
+ */
+int
+mdb_idscope(
+	Operation *op,
+	MDB_txn *txn,
+	ID base,
+	ID *ids,
+	ID *res )
+{
+	struct mdb_info *mdb = (struct mdb_info *) op->o_bd->be_private;
+	MDB_dbi dbi = mdb->mi_dn2id;
+	MDB_val		key, data;
+	MDB_cursor	*cursor;
+	ID ida, id, cid = 0, ci0 = 0, idc = 0;
+	char	*ptr;
+	int		rc, copy;
+
+	key.mv_size = sizeof(ID);
+
+	MDB_IDL_ZERO( res );
+
+	rc = mdb_cursor_open( txn, dbi, &cursor );
+	if ( rc ) return rc;
+
+	/* first see if base has any children at all */
+	key.mv_data = &base;
+	rc = mdb_cursor_get( cursor, &key, &data, MDB_SET );
+	if ( rc ) {
+		goto leave;
+	}
+	{
+		size_t dkids;
+		rc = mdb_cursor_count( cursor, &dkids );
+		if ( rc == 0 ) {
+			if ( dkids < 2 ) {
+				goto leave;
+			}
+		}
+	}
+
+	ida = mdb_idl_first( ids, &cid );
+
+	/* Don't bother moving out of ids if it's a range */
+	if (!MDB_IDL_IS_RANGE(ids)) {
+		idc = ids[0];
+		ci0 = cid;
+	}
+
+	while (ida != NOID) {
+		copy = 1;
+		id = ida;
+		while (id) {
+			key.mv_data = &id;
+			rc = mdb_cursor_get( cursor, &key, &data, MDB_SET );
+			if ( rc ) {
+				/* not found, drop this from ids */
+				copy = 0;
+				break;
+			}
+			ptr = data.mv_data;
+			ptr += data.mv_size - sizeof(ID);
+			memcpy( &id, ptr, sizeof(ID) );
+			if ( id == base ) {
+				if ( res[0] >= MDB_IDL_DB_SIZE-1 ) {
+					/* too many aliases in scope. Fallback to range */
+					MDB_IDL_RANGE( res, MDB_IDL_FIRST( ids ), MDB_IDL_LAST( ids ));
+					goto leave;
+				}
+				res[0]++;
+				res[res[0]] = ida;
+				copy = 0;
+				break;
+			}
+			if ( op->ors_scope == LDAP_SCOPE_ONELEVEL )
+				break;
+		}
+		if (idc) {
+			if (copy) {
+				if (ci0 != cid)
+					ids[ci0] = ids[cid];
+				ci0++;
+			} else
+				idc--;
+		}
+		ida = mdb_idl_next( ids, &cid );
+	}
+	if (!MDB_IDL_IS_RANGE( ids ))
+		ids[0] = idc;
+
+leave:
+	mdb_cursor_close( cursor );
+	return rc;
+}
+
+/* See if base is a child of any of the scopes
+ */
+int
+mdb_idscopes(
+	Operation *op,
+	IdScopes *isc )
+{
+	struct mdb_info *mdb = (struct mdb_info *) op->o_bd->be_private;
+	MDB_dbi dbi = mdb->mi_dn2id;
+	MDB_val		key, data;
+	ID id, prev;
+	ID2 id2;
+	char	*ptr;
+	int		rc = 0;
+	unsigned int x;
+	unsigned int nrlen, rlen;
+	diskNode *d;
+
+	key.mv_size = sizeof(ID);
+
+	if ( !isc->mc ) {
+		rc = mdb_cursor_open( isc->mt, dbi, &isc->mc );
+		if ( rc ) return rc;
+	}
+
+	id = isc->id;
+
+	/* Catch entries from deref'd aliases */
+	x = mdb_id2l_search( isc->scopes, id );
+	if ( x <= isc->scopes[0].mid && isc->scopes[x].mid == id ) {
+		isc->nscope = x;
+		return MDB_SUCCESS;
+	}
+
+	isc->sctmp[0].mid = 0;
+	while (id) {
+		if ( !rc ) {
+			key.mv_data = &id;
+			rc = mdb_cursor_get( isc->mc, &key, &data, MDB_SET );
+			if ( rc )
+				return rc;
+
+			/* save RDN info */
+		}
+		d = data.mv_data;
+		nrlen = (d->nrdnlen[0] << 8) | d->nrdnlen[1];
+		rlen = data.mv_size - sizeof(diskNode) - nrlen;
+		isc->nrdns[isc->numrdns].bv_len = nrlen;
+		isc->nrdns[isc->numrdns].bv_val = d->nrdn;
+		isc->rdns[isc->numrdns].bv_len = rlen;
+		isc->rdns[isc->numrdns].bv_val = d->nrdn+nrlen+1;
+		isc->numrdns++;
+
+		if (!rc && id != isc->id) {
+			/* remember our chain of parents */
+			id2.mid = id;
+			id2.mval = data;
+			mdb_id2l_insert( isc->sctmp, &id2 );
+		}
+		ptr = data.mv_data;
+		ptr += data.mv_size - sizeof(ID);
+		prev = id;
+		memcpy( &id, ptr, sizeof(ID) );
+		/* If we didn't advance, some parent is missing */
+		if ( id == prev )
+			return MDB_NOTFOUND;
+
+		x = mdb_id2l_search( isc->scopes, id );
+		if ( x <= isc->scopes[0].mid && isc->scopes[x].mid == id ) {
+			if ( !isc->scopes[x].mval.mv_data ) {
+				/* This node is in scope, add parent chain to scope */
+				int i;
+				for ( i = 1; i <= isc->sctmp[0].mid; i++ ) {
+					rc = mdb_id2l_insert( isc->scopes, &isc->sctmp[i] );
+					if ( rc )
+						break;
+				}
+				/* check id again since inserts may have changed its position */
+				if ( isc->scopes[x].mid != id )
+					x = mdb_id2l_search( isc->scopes, id );
+				isc->nscope = x;
+				return MDB_SUCCESS;
+			}
+			data = isc->scopes[x].mval;
+			rc = 1;
+		}
+		if ( op->ors_scope == LDAP_SCOPE_ONELEVEL )
+			break;
+	}
+	return MDB_SUCCESS;
+}
+
+/* See if ID is a child of any of the scopes,
+ * return MDB_KEYEXIST if so.
+ */
+int
+mdb_idscopechk(
+	Operation *op,
+	IdScopes *isc )
+{
+	struct mdb_info *mdb = (struct mdb_info *) op->o_bd->be_private;
+	MDB_val		key, data;
+	ID id, prev;
+	char	*ptr;
+	int		rc = 0;
+	unsigned int x;
+
+	key.mv_size = sizeof(ID);
+
+	if ( !isc->mc ) {
+		rc = mdb_cursor_open( isc->mt, mdb->mi_dn2id, &isc->mc );
+		if ( rc ) return rc;
+	}
+
+	id = isc->id;
+
+	while (id) {
+		if ( !rc ) {
+			key.mv_data = &id;
+			rc = mdb_cursor_get( isc->mc, &key, &data, MDB_SET );
+			if ( rc )
+				return rc;
+		}
+
+		ptr = data.mv_data;
+		ptr += data.mv_size - sizeof(ID);
+		prev = id;
+		memcpy( &id, ptr, sizeof(ID) );
+		/* If we didn't advance, some parent is missing */
+		if ( id == prev )
+			return MDB_NOTFOUND;
+
+		x = mdb_id2l_search( isc->scopes, id );
+		if ( x <= isc->scopes[0].mid && isc->scopes[x].mid == id )
+			return MDB_KEYEXIST;
+	}
+	return MDB_SUCCESS;
+}
+
+int
+mdb_dn2id_walk(
+	Operation *op,
+	IdScopes *isc
+)
+{
+	MDB_val key, data;
+	diskNode *d;
+	char *ptr;
+	int rc, n;
+	ID nsubs;
+
+	if ( !isc->numrdns ) {
+		key.mv_data = &isc->id;
+		key.mv_size = sizeof(ID);
+		rc = mdb_cursor_get( isc->mc, &key, &data, MDB_SET );
+		isc->scopes[0].mid = isc->id;
+		isc->numrdns++;
+		isc->nscope = 0;
+		/* skip base if not a subtree walk */
+		if ( isc->oscope == LDAP_SCOPE_SUBTREE ||
+			isc->oscope == LDAP_SCOPE_BASE )
+			return rc;
+	}
+	if ( isc->oscope == LDAP_SCOPE_BASE )
+		return MDB_NOTFOUND;
+
+	for (;;) {
+		/* Get next sibling */
+		rc = mdb_cursor_get( isc->mc, &key, &data, MDB_NEXT_DUP );
+		if ( !rc ) {
+			ptr = (char *)data.mv_data + data.mv_size - 2*sizeof(ID);
+			d = data.mv_data;
+			memcpy( &isc->id, ptr, sizeof(ID));
+
+			/* If we're pushing down, see if there's any children to find */
+			if ( isc->nscope ) {
+				ptr += sizeof(ID);
+				memcpy( &nsubs, ptr, sizeof(ID));
+				/* No children, go to next sibling */
+				if ( nsubs < 2 )
+					continue;
+			}
+			n = isc->numrdns;
+			isc->scopes[n].mid = isc->id;
+			n--;
+			isc->nrdns[n].bv_len = ((d->nrdnlen[0] & 0x7f) << 8) | d->nrdnlen[1];
+			isc->nrdns[n].bv_val = d->nrdn;
+			isc->rdns[n].bv_val = d->nrdn+isc->nrdns[n].bv_len+1;
+			isc->rdns[n].bv_len = data.mv_size - sizeof(diskNode) - isc->nrdns[n].bv_len - sizeof(ID);
+			/* return this ID to caller */
+			if ( !isc->nscope )
+				break;
+
+			/* push down to child */
+			key.mv_data = &isc->id;
+			mdb_cursor_get( isc->mc, &key, &data, MDB_SET );
+			isc->nscope = 0;
+			isc->numrdns++;
+			continue;
+
+		} else if ( rc == MDB_NOTFOUND ) {
+			if ( !isc->nscope && isc->oscope != LDAP_SCOPE_ONELEVEL ) {
+				/* reset to first dup */
+				mdb_cursor_get( isc->mc, &key, NULL, MDB_GET_CURRENT );
+				mdb_cursor_get( isc->mc, &key, &data, MDB_SET );
+				isc->nscope = 1;
+				continue;
+			} else {
+				isc->numrdns--;
+				/* stack is empty? */
+				if ( !isc->numrdns )
+					break;
+				/* pop up to prev node */
+				n = isc->numrdns - 1;
+				key.mv_data = &isc->scopes[n].mid;
+				key.mv_size = sizeof(ID);
+				data.mv_data = isc->nrdns[n].bv_val - 2;
+				data.mv_size = 1;	/* just needs to be non-zero, mdb_dup_compare doesn't care */
+				mdb_cursor_get( isc->mc, &key, &data, MDB_GET_BOTH );
+				continue;
+			}
+		} else {
+			break;
+		}
+	}
+	return rc;
+}
+
+/* restore the nrdn/rdn pointers after a txn reset */
+void mdb_dn2id_wrestore (
+	Operation *op,
+	IdScopes *isc
+)
+{
+	MDB_val key, data;
+	diskNode *d;
+	int rc, n, nrlen;
+	char *ptr;
+
+	/* We only need to restore up to the n-1th element,
+	 * the nth element will be replaced anyway
+	 */
+	key.mv_size = sizeof(ID);
+	for ( n=0; n<isc->numrdns-1; n++ ) {
+		key.mv_data = &isc->scopes[n+1].mid;
+		rc = mdb_cursor_get( isc->mc, &key, &data, MDB_SET );
+		if ( rc )
+			continue;
+		/* we can't use this data directly since its nrlen
+		 * is missing the high bit setting, so copy it and
+		 * set it properly. we just copy enough to satisfy
+		 * mdb_dup_compare.
+		 */
+		d = data.mv_data;
+		nrlen = ((d->nrdnlen[0] & 0x7f) << 8) | d->nrdnlen[1];
+		ptr = op->o_tmpalloc( nrlen+2, op->o_tmpmemctx );
+		memcpy( ptr, data.mv_data, nrlen+2 );
+		key.mv_data = &isc->scopes[n].mid;
+		data.mv_data = ptr;
+		data.mv_size = 1;
+		*ptr |= 0x80;
+		mdb_cursor_get( isc->mc, &key, &data, MDB_GET_BOTH );
+		op->o_tmpfree( ptr, op->o_tmpmemctx );
+
+		/* now we're back to where we wanted to be */
+		d = data.mv_data;
+		isc->nrdns[n].bv_val = d->nrdn;
+		isc->rdns[n].bv_val = d->nrdn+isc->nrdns[n].bv_len+1;
+	}
+}