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search.c revision 1.2
      1 /*	$NetBSD: search.c,v 1.2 2020/08/11 13:15:40 christos Exp $	*/
      2 
      3 /* search.c - search operation */
      4 /* $OpenLDAP$ */
      5 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
      6  *
      7  * Copyright 2000-2020 The OpenLDAP Foundation.
      8  * All rights reserved.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted only as authorized by the OpenLDAP
     12  * Public License.
     13  *
     14  * A copy of this license is available in the file LICENSE in the
     15  * top-level directory of the distribution or, alternatively, at
     16  * <http://www.OpenLDAP.org/license.html>.
     17  */
     18 
     19 #include <sys/cdefs.h>
     20 __RCSID("$NetBSD: search.c,v 1.2 2020/08/11 13:15:40 christos Exp $");
     21 
     22 #include "portable.h"
     23 
     24 #include <stdio.h>
     25 #include <ac/string.h>
     26 
     27 #include "back-mdb.h"
     28 #include "idl.h"
     29 
     30 static int base_candidate(
     31 	BackendDB	*be,
     32 	Entry	*e,
     33 	ID		*ids );
     34 
     35 static int search_candidates(
     36 	Operation *op,
     37 	SlapReply *rs,
     38 	Entry *e,
     39 	IdScopes *isc,
     40 	MDB_cursor *mci,
     41 	ID	*ids,
     42 	ID *stack );
     43 
     44 static int parse_paged_cookie( Operation *op, SlapReply *rs );
     45 
     46 static void send_paged_response(
     47 	Operation *op,
     48 	SlapReply *rs,
     49 	ID  *lastid,
     50 	int tentries );
     51 
     52 /* Dereference aliases for a single alias entry. Return the final
     53  * dereferenced entry on success, NULL on any failure.
     54  */
     55 static Entry * deref_base (
     56 	Operation *op,
     57 	SlapReply *rs,
     58 	Entry *e,
     59 	Entry **matched,
     60 	MDB_txn *txn,
     61 	ID	*tmp,
     62 	ID	*visited )
     63 {
     64 	struct berval ndn;
     65 
     66 	rs->sr_err = LDAP_ALIAS_DEREF_PROBLEM;
     67 	rs->sr_text = "maximum deref depth exceeded";
     68 
     69 	for (;;) {
     70 		/* Remember the last entry we looked at, so we can
     71 		 * report broken links
     72 		 */
     73 		*matched = e;
     74 
     75 		if (MDB_IDL_N(tmp) >= op->o_bd->be_max_deref_depth) {
     76 			e = NULL;
     77 			break;
     78 		}
     79 
     80 		/* If this is part of a subtree or onelevel search,
     81 		 * have we seen this ID before? If so, quit.
     82 		 */
     83 		if ( visited && mdb_idl_insert( visited, e->e_id ) ) {
     84 			e = NULL;
     85 			break;
     86 		}
     87 
     88 		/* If we've seen this ID during this deref iteration,
     89 		 * we've hit a loop.
     90 		 */
     91 		if ( mdb_idl_insert( tmp, e->e_id ) ) {
     92 			rs->sr_err = LDAP_ALIAS_PROBLEM;
     93 			rs->sr_text = "circular alias";
     94 			e = NULL;
     95 			break;
     96 		}
     97 
     98 		/* If there was a problem getting the aliasedObjectName,
     99 		 * get_alias_dn will have set the error status.
    100 		 */
    101 		if ( get_alias_dn(e, &ndn, &rs->sr_err, &rs->sr_text) ) {
    102 			e = NULL;
    103 			break;
    104 		}
    105 
    106 		rs->sr_err = mdb_dn2entry( op, txn, NULL, &ndn, &e, NULL, 0 );
    107 		if (rs->sr_err) {
    108 			rs->sr_err = LDAP_ALIAS_PROBLEM;
    109 			rs->sr_text = "aliasedObject not found";
    110 			break;
    111 		}
    112 
    113 		/* Free the previous entry, continue to work with the
    114 		 * one we just retrieved.
    115 		 */
    116 		mdb_entry_return( op, *matched );
    117 
    118 		/* We found a regular entry. Return this to the caller.
    119 		 */
    120 		if (!is_entry_alias(e)) {
    121 			rs->sr_err = LDAP_SUCCESS;
    122 			rs->sr_text = NULL;
    123 			break;
    124 		}
    125 	}
    126 	return e;
    127 }
    128 
    129 /* Look for and dereference all aliases within the search scope.
    130  * Requires "stack" to be able to hold 6 levels of DB_SIZE IDLs.
    131  * Of course we're hardcoded to require a minimum of 8 UM_SIZE
    132  * IDLs so this is never a problem.
    133  */
    134 static int search_aliases(
    135 	Operation *op,
    136 	SlapReply *rs,
    137 	ID e_id,
    138 	IdScopes *isc,
    139 	MDB_cursor *mci,
    140 	ID *stack )
    141 {
    142 	ID *aliases, *curscop, *visited, *newsubs, *oldsubs, *tmp;
    143 	ID cursora, ida, cursoro, ido;
    144 	Entry *matched, *a;
    145 	struct berval bv_alias = BER_BVC( "alias" );
    146 	AttributeAssertion aa_alias = ATTRIBUTEASSERTION_INIT;
    147 	Filter	af;
    148 
    149 	aliases = stack;	/* IDL of all aliases in the database */
    150 	curscop = aliases + MDB_IDL_DB_SIZE;	/* Aliases in the current scope */
    151 	visited = curscop + MDB_IDL_DB_SIZE;	/* IDs we've seen in this search */
    152 	newsubs = visited + MDB_IDL_DB_SIZE;	/* New subtrees we've added */
    153 	oldsubs = newsubs + MDB_IDL_DB_SIZE;	/* Subtrees added previously */
    154 	tmp = oldsubs + MDB_IDL_DB_SIZE;	/* Scratch space for deref_base() */
    155 
    156 	af.f_choice = LDAP_FILTER_EQUALITY;
    157 	af.f_ava = &aa_alias;
    158 	af.f_av_desc = slap_schema.si_ad_objectClass;
    159 	af.f_av_value = bv_alias;
    160 	af.f_next = NULL;
    161 
    162 	/* Find all aliases in database */
    163 	MDB_IDL_ZERO( aliases );
    164 	rs->sr_err = mdb_filter_candidates( op, isc->mt, &af, aliases,
    165 		curscop, visited );
    166 	if (rs->sr_err != LDAP_SUCCESS || MDB_IDL_IS_ZERO( aliases )) {
    167 		return rs->sr_err;
    168 	}
    169 	if ( op->ors_limit	/* isroot == FALSE */ &&
    170 		op->ors_limit->lms_s_unchecked != -1 &&
    171 		MDB_IDL_N( aliases ) > (unsigned) op->ors_limit->lms_s_unchecked )
    172 	{
    173 		return LDAP_ADMINLIMIT_EXCEEDED;
    174 	}
    175 	oldsubs[0] = 1;
    176 	oldsubs[1] = e_id;
    177 
    178 	MDB_IDL_ZERO( visited );
    179 	MDB_IDL_ZERO( newsubs );
    180 
    181 	cursoro = 0;
    182 	ido = mdb_idl_first( oldsubs, &cursoro );
    183 
    184 	for (;;) {
    185 		/* Set curscop to only the aliases in the current scope. Start with
    186 		 * all the aliases, then get the intersection with the scope.
    187 		 */
    188 		rs->sr_err = mdb_idscope( op, isc->mt, e_id, aliases, curscop );
    189 
    190 		/* Dereference all of the aliases in the current scope. */
    191 		cursora = 0;
    192 		for (ida = mdb_idl_first(curscop, &cursora); ida != NOID;
    193 			ida = mdb_idl_next(curscop, &cursora))
    194 		{
    195 			rs->sr_err = mdb_id2entry(op, mci, ida, &a);
    196 			if (rs->sr_err != LDAP_SUCCESS) {
    197 				continue;
    198 			}
    199 
    200 			/* This should only happen if the curscop IDL has maxed out and
    201 			 * turned into a range that spans IDs indiscriminately
    202 			 */
    203 			if (!is_entry_alias(a)) {
    204 				mdb_entry_return(op, a);
    205 				continue;
    206 			}
    207 
    208 			/* Actually dereference the alias */
    209 			MDB_IDL_ZERO(tmp);
    210 			a = deref_base( op, rs, a, &matched, isc->mt,
    211 				tmp, visited );
    212 			if (a) {
    213 				/* If the target was not already in our current scopes,
    214 				 * make note of it in the newsubs list.
    215 				 */
    216 				ID2 mid;
    217 				mid.mid = a->e_id;
    218 				mid.mval.mv_data = NULL;
    219 				if (op->ors_scope == LDAP_SCOPE_SUBTREE) {
    220 					isc->id = a->e_id;
    221 					/* if ID is a child of any of our current scopes,
    222 					 * ignore it, it's already included.
    223 					 */
    224 					if (mdb_idscopechk(op, isc))
    225 						goto skip;
    226 				}
    227 				if (mdb_id2l_insert(isc->scopes, &mid) == 0) {
    228 					mdb_idl_insert(newsubs, a->e_id);
    229 				}
    230 skip:			mdb_entry_return( op, a );
    231 
    232 			} else if (matched) {
    233 				/* Alias could not be dereferenced, or it deref'd to
    234 				 * an ID we've already seen. Ignore it.
    235 				 */
    236 				mdb_entry_return( op, matched );
    237 				rs->sr_text = NULL;
    238 				rs->sr_err = 0;
    239 			}
    240 		}
    241 		/* If this is a OneLevel search, we're done; oldsubs only had one
    242 		 * ID in it. For a Subtree search, oldsubs may be a list of scope IDs.
    243 		 */
    244 		if ( op->ors_scope == LDAP_SCOPE_ONELEVEL ) break;
    245 nextido:
    246 		ido = mdb_idl_next( oldsubs, &cursoro );
    247 
    248 		/* If we're done processing the old scopes, did we add any new
    249 		 * scopes in this iteration? If so, go back and do those now.
    250 		 */
    251 		if (ido == NOID) {
    252 			if (MDB_IDL_IS_ZERO(newsubs)) break;
    253 			MDB_IDL_CPY(oldsubs, newsubs);
    254 			MDB_IDL_ZERO(newsubs);
    255 			cursoro = 0;
    256 			ido = mdb_idl_first( oldsubs, &cursoro );
    257 		}
    258 
    259 		/* Find the entry corresponding to the next scope. If it can't
    260 		 * be found, ignore it and move on. This should never happen;
    261 		 * we should never see the ID of an entry that doesn't exist.
    262 		 */
    263 		{
    264 			MDB_val edata;
    265 			rs->sr_err = mdb_id2edata(op, mci, ido, &edata);
    266 			if ( rs->sr_err != MDB_SUCCESS ) {
    267 				goto nextido;
    268 			}
    269 			e_id = ido;
    270 		}
    271 	}
    272 	return rs->sr_err;
    273 }
    274 
    275 /* Get the next ID from the DB. Used if the candidate list is
    276  * a range and simple iteration hits missing entryIDs
    277  */
    278 static int
    279 mdb_get_nextid(MDB_cursor *mci, ID *cursor)
    280 {
    281 	MDB_val key;
    282 	ID id;
    283 	int rc;
    284 
    285 	id = *cursor + 1;
    286 	key.mv_data = &id;
    287 	key.mv_size = sizeof(ID);
    288 	rc = mdb_cursor_get( mci, &key, NULL, MDB_SET_RANGE );
    289 	if ( rc )
    290 		return rc;
    291 	memcpy( cursor, key.mv_data, sizeof(ID));
    292 	return 0;
    293 }
    294 
    295 static void scope_chunk_free( void *key, void *data )
    296 {
    297 	ID2 *p1, *p2;
    298 	for (p1 = data; p1; p1 = p2) {
    299 		p2 = p1[0].mval.mv_data;
    300 		ber_memfree_x(p1, NULL);
    301 	}
    302 }
    303 
    304 static ID2 *scope_chunk_get( Operation *op )
    305 {
    306 	ID2 *ret = NULL;
    307 
    308 	ldap_pvt_thread_pool_getkey( op->o_threadctx, (void *)scope_chunk_get,
    309 			(void *)&ret, NULL );
    310 	if ( !ret ) {
    311 		ret = ch_malloc( MDB_IDL_UM_SIZE * sizeof( ID2 ));
    312 	} else {
    313 		void *r2 = ret[0].mval.mv_data;
    314 		ldap_pvt_thread_pool_setkey( op->o_threadctx, (void *)scope_chunk_get,
    315 			r2, scope_chunk_free, NULL, NULL );
    316 	}
    317 	return ret;
    318 }
    319 
    320 static void scope_chunk_ret( Operation *op, ID2 *scopes )
    321 {
    322 	void *ret = NULL;
    323 
    324 	ldap_pvt_thread_pool_getkey( op->o_threadctx, (void *)scope_chunk_get,
    325 			&ret, NULL );
    326 	scopes[0].mval.mv_data = ret;
    327 	ldap_pvt_thread_pool_setkey( op->o_threadctx, (void *)scope_chunk_get,
    328 			(void *)scopes, scope_chunk_free, NULL, NULL );
    329 }
    330 
    331 static void *search_stack( Operation *op );
    332 
    333 typedef struct ww_ctx {
    334 	MDB_txn *txn;
    335 	MDB_cursor *mcd;	/* if set, save cursor context */
    336 	ID key;
    337 	MDB_val data;
    338 	int flag;
    339 	unsigned nentries;
    340 } ww_ctx;
    341 
    342 /* ITS#7904 if we get blocked while writing results to client,
    343  * release the current reader txn and reacquire it after we
    344  * unblock.
    345  * Slight problem - if we're doing a scope-based walk (mdb_dn2id_walk)
    346  * to return results, we need to remember the state of the mcd cursor.
    347  * If the node that cursor was pointing to gets deleted while we're
    348  * blocked, we may be unable to restore the cursor position. In that
    349  * case return an LDAP_BUSY error - let the client know this search
    350  * couldn't succeed, but might succeed on a retry.
    351  */
    352 static void
    353 mdb_rtxn_snap( Operation *op, ww_ctx *ww )
    354 {
    355 	/* save cursor position and release read txn */
    356 	if ( ww->mcd ) {
    357 		MDB_val key, data;
    358 		mdb_cursor_get( ww->mcd, &key, &data, MDB_GET_CURRENT );
    359 		memcpy( &ww->key, key.mv_data, sizeof(ID) );
    360 		ww->data.mv_size = data.mv_size;
    361 		ww->data.mv_data = op->o_tmpalloc( data.mv_size, op->o_tmpmemctx );
    362 		memcpy(ww->data.mv_data, data.mv_data, data.mv_size);
    363 	}
    364 	mdb_txn_reset( ww->txn );
    365 	ww->flag = 1;
    366 }
    367 
    368 static void
    369 mdb_writewait( Operation *op, slap_callback *sc )
    370 {
    371 	ww_ctx *ww = sc->sc_private;
    372 	if ( !ww->flag ) {
    373 		mdb_rtxn_snap( op, ww );
    374 	}
    375 }
    376 
    377 static int
    378 mdb_waitfixup( Operation *op, ww_ctx *ww, MDB_cursor *mci, MDB_cursor *mcd, IdScopes *isc )
    379 {
    380 	MDB_val key;
    381 	int rc = 0;
    382 	ww->flag = 0;
    383 	mdb_txn_renew( ww->txn );
    384 	mdb_cursor_renew( ww->txn, mci );
    385 	mdb_cursor_renew( ww->txn, mcd );
    386 
    387 	key.mv_size = sizeof(ID);
    388 	if ( ww->mcd ) {	/* scope-based search using dn2id_walk */
    389 		MDB_val data;
    390 
    391 		if ( isc->numrdns )
    392 			mdb_dn2id_wrestore( op, isc );
    393 
    394 		key.mv_data = &ww->key;
    395 		data = ww->data;
    396 		rc = mdb_cursor_get( mcd, &key, &data, MDB_GET_BOTH );
    397 		if ( rc == MDB_NOTFOUND ) {
    398 			data = ww->data;
    399 			rc = mdb_cursor_get( mcd, &key, &data, MDB_GET_BOTH_RANGE );
    400 			/* the loop will skip this node using NEXT_DUP but we want it
    401 			 * sent, so go back one space first
    402 			 */
    403 			if ( rc == MDB_SUCCESS )
    404 				mdb_cursor_get( mcd, &key, &data, MDB_PREV_DUP );
    405 			else
    406 				rc = LDAP_BUSY;
    407 		} else if ( rc ) {
    408 			rc = LDAP_OTHER;
    409 		}
    410 		op->o_tmpfree( ww->data.mv_data, op->o_tmpmemctx );
    411 		ww->data.mv_data = NULL;
    412 	} else if ( isc->scopes[0].mid > 1 ) {	/* candidate-based search */
    413 		int i;
    414 		for ( i=1; i<isc->scopes[0].mid; i++ ) {
    415 			if ( !isc->scopes[i].mval.mv_data )
    416 				continue;
    417 			key.mv_data = &isc->scopes[i].mid;
    418 			mdb_cursor_get( mcd, &key, &isc->scopes[i].mval, MDB_SET );
    419 		}
    420 	}
    421 	return rc;
    422 }
    423 
    424 int
    425 mdb_search( Operation *op, SlapReply *rs )
    426 {
    427 	struct mdb_info *mdb = (struct mdb_info *) op->o_bd->be_private;
    428 	ID		id, cursor, nsubs, ncand, cscope;
    429 	ID		lastid = NOID;
    430 	ID		candidates[MDB_IDL_UM_SIZE];
    431 	ID		iscopes[MDB_IDL_DB_SIZE];
    432 	ID2		*scopes;
    433 	void	*stack;
    434 	Entry		*e = NULL, *base = NULL;
    435 	Entry		*matched = NULL;
    436 	AttributeName	*attrs;
    437 	slap_mask_t	mask;
    438 	time_t		stoptime;
    439 	int		manageDSAit;
    440 	int		tentries = 0;
    441 	IdScopes	isc;
    442 	MDB_cursor	*mci, *mcd;
    443 	ww_ctx wwctx;
    444 	slap_callback cb = { 0 };
    445 
    446 	mdb_op_info	opinfo = {{{0}}}, *moi = &opinfo;
    447 	MDB_txn			*ltid = NULL;
    448 
    449 	Debug( LDAP_DEBUG_TRACE, "=> " LDAP_XSTRING(mdb_search) "\n", 0, 0, 0);
    450 	attrs = op->oq_search.rs_attrs;
    451 
    452 	manageDSAit = get_manageDSAit( op );
    453 
    454 	rs->sr_err = mdb_opinfo_get( op, mdb, 1, &moi );
    455 	switch(rs->sr_err) {
    456 	case 0:
    457 		break;
    458 	default:
    459 		send_ldap_error( op, rs, LDAP_OTHER, "internal error" );
    460 		return rs->sr_err;
    461 	}
    462 
    463 	ltid = moi->moi_txn;
    464 
    465 	rs->sr_err = mdb_cursor_open( ltid, mdb->mi_id2entry, &mci );
    466 	if ( rs->sr_err ) {
    467 		send_ldap_error( op, rs, LDAP_OTHER, "internal error" );
    468 		return rs->sr_err;
    469 	}
    470 
    471 	rs->sr_err = mdb_cursor_open( ltid, mdb->mi_dn2id, &mcd );
    472 	if ( rs->sr_err ) {
    473 		mdb_cursor_close( mci );
    474 		send_ldap_error( op, rs, LDAP_OTHER, "internal error" );
    475 		return rs->sr_err;
    476 	}
    477 
    478 	scopes = scope_chunk_get( op );
    479 	stack = search_stack( op );
    480 	isc.mt = ltid;
    481 	isc.mc = mcd;
    482 	isc.scopes = scopes;
    483 	isc.oscope = op->ors_scope;
    484 	isc.sctmp = stack;
    485 
    486 	if ( op->ors_deref & LDAP_DEREF_FINDING ) {
    487 		MDB_IDL_ZERO(candidates);
    488 	}
    489 dn2entry_retry:
    490 	/* get entry with reader lock */
    491 	rs->sr_err = mdb_dn2entry( op, ltid, mcd, &op->o_req_ndn, &e, &nsubs, 1 );
    492 
    493 	switch(rs->sr_err) {
    494 	case MDB_NOTFOUND:
    495 		matched = e;
    496 		e = NULL;
    497 		break;
    498 	case 0:
    499 		break;
    500 	case LDAP_BUSY:
    501 		send_ldap_error( op, rs, LDAP_BUSY, "ldap server busy" );
    502 		goto done;
    503 	default:
    504 		send_ldap_error( op, rs, LDAP_OTHER, "internal error" );
    505 		goto done;
    506 	}
    507 
    508 	if ( op->ors_deref & LDAP_DEREF_FINDING ) {
    509 		if ( matched && is_entry_alias( matched )) {
    510 			struct berval stub;
    511 
    512 			stub.bv_val = op->o_req_ndn.bv_val;
    513 			stub.bv_len = op->o_req_ndn.bv_len - matched->e_nname.bv_len - 1;
    514 			e = deref_base( op, rs, matched, &matched, ltid,
    515 				candidates, NULL );
    516 			if ( e ) {
    517 				build_new_dn( &op->o_req_ndn, &e->e_nname, &stub,
    518 					op->o_tmpmemctx );
    519 				mdb_entry_return(op, e);
    520 				matched = NULL;
    521 				goto dn2entry_retry;
    522 			}
    523 		} else if ( e && is_entry_alias( e )) {
    524 			e = deref_base( op, rs, e, &matched, ltid,
    525 				candidates, NULL );
    526 		}
    527 	}
    528 
    529 	if ( e == NULL ) {
    530 		struct berval matched_dn = BER_BVNULL;
    531 
    532 		if ( matched != NULL ) {
    533 			BerVarray erefs = NULL;
    534 
    535 			/* return referral only if "disclose"
    536 			 * is granted on the object */
    537 			if ( ! access_allowed( op, matched,
    538 						slap_schema.si_ad_entry,
    539 						NULL, ACL_DISCLOSE, NULL ) )
    540 			{
    541 				rs->sr_err = LDAP_NO_SUCH_OBJECT;
    542 
    543 			} else {
    544 				ber_dupbv( &matched_dn, &matched->e_name );
    545 
    546 				erefs = is_entry_referral( matched )
    547 					? get_entry_referrals( op, matched )
    548 					: NULL;
    549 				if ( rs->sr_err == MDB_NOTFOUND )
    550 					rs->sr_err = LDAP_REFERRAL;
    551 				rs->sr_matched = matched_dn.bv_val;
    552 			}
    553 
    554 			mdb_entry_return(op, matched);
    555 			matched = NULL;
    556 
    557 			if ( erefs ) {
    558 				rs->sr_ref = referral_rewrite( erefs, &matched_dn,
    559 					&op->o_req_dn, op->oq_search.rs_scope );
    560 				ber_bvarray_free( erefs );
    561 			}
    562 
    563 		} else {
    564 			rs->sr_ref = referral_rewrite( default_referral,
    565 				NULL, &op->o_req_dn, op->oq_search.rs_scope );
    566 			rs->sr_err = rs->sr_ref != NULL ? LDAP_REFERRAL : LDAP_NO_SUCH_OBJECT;
    567 		}
    568 
    569 		send_ldap_result( op, rs );
    570 
    571 		if ( rs->sr_ref ) {
    572 			ber_bvarray_free( rs->sr_ref );
    573 			rs->sr_ref = NULL;
    574 		}
    575 		if ( !BER_BVISNULL( &matched_dn ) ) {
    576 			ber_memfree( matched_dn.bv_val );
    577 			rs->sr_matched = NULL;
    578 		}
    579 		goto done;
    580 	}
    581 
    582 	/* NOTE: __NEW__ "search" access is required
    583 	 * on searchBase object */
    584 	if ( ! access_allowed_mask( op, e, slap_schema.si_ad_entry,
    585 				NULL, ACL_SEARCH, NULL, &mask ) )
    586 	{
    587 		if ( !ACL_GRANT( mask, ACL_DISCLOSE ) ) {
    588 			rs->sr_err = LDAP_NO_SUCH_OBJECT;
    589 		} else {
    590 			rs->sr_err = LDAP_INSUFFICIENT_ACCESS;
    591 		}
    592 
    593 		mdb_entry_return( op,e);
    594 		send_ldap_result( op, rs );
    595 		goto done;
    596 	}
    597 
    598 	if ( !manageDSAit && is_entry_referral( e ) ) {
    599 		/* entry is a referral */
    600 		struct berval matched_dn = BER_BVNULL;
    601 		BerVarray erefs = NULL;
    602 
    603 		ber_dupbv( &matched_dn, &e->e_name );
    604 		erefs = get_entry_referrals( op, e );
    605 
    606 		rs->sr_err = LDAP_REFERRAL;
    607 
    608 		mdb_entry_return( op, e );
    609 		e = NULL;
    610 
    611 		if ( erefs ) {
    612 			rs->sr_ref = referral_rewrite( erefs, &matched_dn,
    613 				&op->o_req_dn, op->oq_search.rs_scope );
    614 			ber_bvarray_free( erefs );
    615 
    616 			if ( !rs->sr_ref ) {
    617 				rs->sr_text = "bad_referral object";
    618 			}
    619 		}
    620 
    621 		Debug( LDAP_DEBUG_TRACE,
    622 			LDAP_XSTRING(mdb_search) ": entry is referral\n",
    623 			0, 0, 0 );
    624 
    625 		rs->sr_matched = matched_dn.bv_val;
    626 		send_ldap_result( op, rs );
    627 
    628 		ber_bvarray_free( rs->sr_ref );
    629 		rs->sr_ref = NULL;
    630 		ber_memfree( matched_dn.bv_val );
    631 		rs->sr_matched = NULL;
    632 		goto done;
    633 	}
    634 
    635 	if ( get_assert( op ) &&
    636 		( test_filter( op, e, get_assertion( op )) != LDAP_COMPARE_TRUE ))
    637 	{
    638 		rs->sr_err = LDAP_ASSERTION_FAILED;
    639 		mdb_entry_return( op,e);
    640 		send_ldap_result( op, rs );
    641 		goto done;
    642 	}
    643 
    644 	/* compute it anyway; root does not use it */
    645 	stoptime = op->o_time + op->ors_tlimit;
    646 
    647 	base = e;
    648 
    649 	e = NULL;
    650 
    651 	/* select candidates */
    652 	if ( op->oq_search.rs_scope == LDAP_SCOPE_BASE ) {
    653 		rs->sr_err = base_candidate( op->o_bd, base, candidates );
    654 		scopes[0].mid = 0;
    655 		ncand = 1;
    656 	} else {
    657 		if ( op->ors_scope == LDAP_SCOPE_ONELEVEL ) {
    658 			size_t nkids;
    659 			MDB_val key, data;
    660 			key.mv_data = &base->e_id;
    661 			key.mv_size = sizeof( ID );
    662 			mdb_cursor_get( mcd, &key, &data, MDB_SET );
    663 			mdb_cursor_count( mcd, &nkids );
    664 			nsubs = nkids - 1;
    665 		} else if ( !base->e_id ) {
    666 			/* we don't maintain nsubs for entryID 0.
    667 			 * just grab entry count from id2entry stat
    668 			 */
    669 			MDB_stat ms;
    670 			mdb_stat( ltid, mdb->mi_id2entry, &ms );
    671 			nsubs = ms.ms_entries;
    672 		}
    673 		MDB_IDL_ZERO( candidates );
    674 		scopes[0].mid = 1;
    675 		scopes[1].mid = base->e_id;
    676 		scopes[1].mval.mv_data = NULL;
    677 		rs->sr_err = search_candidates( op, rs, base,
    678 			&isc, mci, candidates, stack );
    679 
    680 		if ( rs->sr_err == LDAP_ADMINLIMIT_EXCEEDED )
    681 			goto adminlimit;
    682 
    683 		ncand = MDB_IDL_N( candidates );
    684 		if ( !base->e_id || ncand == NOID ) {
    685 			/* grab entry count from id2entry stat
    686 			 */
    687 			MDB_stat ms;
    688 			mdb_stat( ltid, mdb->mi_id2entry, &ms );
    689 			if ( !base->e_id )
    690 				nsubs = ms.ms_entries;
    691 			if ( ncand == NOID )
    692 				ncand = ms.ms_entries;
    693 		}
    694 	}
    695 
    696 	/* start cursor at beginning of candidates.
    697 	 */
    698 	cursor = 0;
    699 
    700 	if ( candidates[0] == 0 ) {
    701 		Debug( LDAP_DEBUG_TRACE,
    702 			LDAP_XSTRING(mdb_search) ": no candidates\n",
    703 			0, 0, 0 );
    704 
    705 		goto nochange;
    706 	}
    707 
    708 	/* if not root and candidates exceed to-be-checked entries, abort */
    709 	if ( op->ors_limit	/* isroot == FALSE */ &&
    710 		op->ors_limit->lms_s_unchecked != -1 &&
    711 		ncand > (unsigned) op->ors_limit->lms_s_unchecked )
    712 	{
    713 		rs->sr_err = LDAP_ADMINLIMIT_EXCEEDED;
    714 adminlimit:
    715 		send_ldap_result( op, rs );
    716 		rs->sr_err = LDAP_SUCCESS;
    717 		goto done;
    718 	}
    719 
    720 	if ( op->ors_limit == NULL	/* isroot == TRUE */ ||
    721 		!op->ors_limit->lms_s_pr_hide )
    722 	{
    723 		tentries = ncand;
    724 	}
    725 
    726 	wwctx.flag = 0;
    727 	/* If we're running in our own read txn */
    728 	if (  moi == &opinfo ) {
    729 		cb.sc_writewait = mdb_writewait;
    730 		cb.sc_private = &wwctx;
    731 		wwctx.txn = ltid;
    732 		wwctx.mcd = NULL;
    733 		cb.sc_next = op->o_callback;
    734 		op->o_callback = &cb;
    735 	}
    736 
    737 	if ( get_pagedresults( op ) > SLAP_CONTROL_IGNORED ) {
    738 		PagedResultsState *ps = op->o_pagedresults_state;
    739 		/* deferred cookie parsing */
    740 		rs->sr_err = parse_paged_cookie( op, rs );
    741 		if ( rs->sr_err != LDAP_SUCCESS ) {
    742 			send_ldap_result( op, rs );
    743 			goto done;
    744 		}
    745 
    746 		cursor = (ID) ps->ps_cookie;
    747 		if ( cursor && ps->ps_size == 0 ) {
    748 			rs->sr_err = LDAP_SUCCESS;
    749 			rs->sr_text = "search abandoned by pagedResult size=0";
    750 			send_ldap_result( op, rs );
    751 			goto done;
    752 		}
    753 		id = mdb_idl_first( candidates, &cursor );
    754 		if ( id == NOID ) {
    755 			Debug( LDAP_DEBUG_TRACE,
    756 				LDAP_XSTRING(mdb_search)
    757 				": no paged results candidates\n",
    758 				0, 0, 0 );
    759 			send_paged_response( op, rs, &lastid, 0 );
    760 
    761 			rs->sr_err = LDAP_OTHER;
    762 			goto done;
    763 		}
    764 		if ( id == (ID)ps->ps_cookie )
    765 			id = mdb_idl_next( candidates, &cursor );
    766 		nsubs = ncand;	/* always bypass scope'd search */
    767 		goto loop_begin;
    768 	}
    769 	if ( nsubs < ncand ) {
    770 		int rc;
    771 		/* Do scope-based search */
    772 
    773 		/* if any alias scopes were set, save them */
    774 		if (scopes[0].mid > 1) {
    775 			cursor = 1;
    776 			for (cscope = 1; cscope <= scopes[0].mid; cscope++) {
    777 				/* Ignore the original base */
    778 				if (scopes[cscope].mid == base->e_id)
    779 					continue;
    780 				iscopes[cursor++] = scopes[cscope].mid;
    781 			}
    782 			iscopes[0] = scopes[0].mid - 1;
    783 		} else {
    784 			iscopes[0] = 0;
    785 		}
    786 
    787 		wwctx.mcd = mcd;
    788 		isc.id = base->e_id;
    789 		isc.numrdns = 0;
    790 		rc = mdb_dn2id_walk( op, &isc );
    791 		if ( rc )
    792 			id = NOID;
    793 		else
    794 			id = isc.id;
    795 		cscope = 0;
    796 	} else {
    797 		id = mdb_idl_first( candidates, &cursor );
    798 	}
    799 
    800 	while (id != NOID)
    801 	{
    802 		int scopeok;
    803 		MDB_val edata;
    804 
    805 loop_begin:
    806 
    807 		/* check for abandon */
    808 		if ( op->o_abandon ) {
    809 			rs->sr_err = SLAPD_ABANDON;
    810 			send_ldap_result( op, rs );
    811 			goto done;
    812 		}
    813 
    814 		/* mostly needed by internal searches,
    815 		 * e.g. related to syncrepl, for whom
    816 		 * abandon does not get set... */
    817 		if ( slapd_shutdown ) {
    818 			rs->sr_err = LDAP_UNAVAILABLE;
    819 			send_ldap_disconnect( op, rs );
    820 			goto done;
    821 		}
    822 
    823 		/* check time limit */
    824 		if ( op->ors_tlimit != SLAP_NO_LIMIT
    825 				&& slap_get_time() > stoptime )
    826 		{
    827 			rs->sr_err = LDAP_TIMELIMIT_EXCEEDED;
    828 			rs->sr_ref = rs->sr_v2ref;
    829 			send_ldap_result( op, rs );
    830 			rs->sr_err = LDAP_SUCCESS;
    831 			goto done;
    832 		}
    833 
    834 
    835 		if ( nsubs < ncand ) {
    836 			unsigned i;
    837 			/* Is this entry in the candidate list? */
    838 			scopeok = 0;
    839 			if (MDB_IDL_IS_RANGE( candidates )) {
    840 				if ( id >= MDB_IDL_RANGE_FIRST( candidates ) &&
    841 					id <= MDB_IDL_RANGE_LAST( candidates ))
    842 					scopeok = 1;
    843 			} else {
    844 				i = mdb_idl_search( candidates, id );
    845 				if (i <= candidates[0] && candidates[i] == id )
    846 					scopeok = 1;
    847 			}
    848 			if ( scopeok )
    849 				goto scopeok;
    850 			goto loop_continue;
    851 		}
    852 
    853 		/* Does this candidate actually satisfy the search scope?
    854 		 */
    855 		scopeok = 0;
    856 		isc.numrdns = 0;
    857 		switch( op->ors_scope ) {
    858 		case LDAP_SCOPE_BASE:
    859 			/* This is always true, yes? */
    860 			if ( id == base->e_id ) scopeok = 1;
    861 			break;
    862 
    863 #ifdef LDAP_SCOPE_CHILDREN
    864 		case LDAP_SCOPE_CHILDREN:
    865 			if ( id == base->e_id ) break;
    866 			/* Fall-thru */
    867 #endif
    868 		case LDAP_SCOPE_SUBTREE:
    869 			if ( id == base->e_id ) {
    870 				scopeok = 1;
    871 				break;
    872 			}
    873 			/* Fall-thru */
    874 		case LDAP_SCOPE_ONELEVEL:
    875 			if ( id == base->e_id ) break;
    876 			isc.id = id;
    877 			isc.nscope = 0;
    878 			rs->sr_err = mdb_idscopes( op, &isc );
    879 			if ( rs->sr_err == MDB_SUCCESS ) {
    880 				if ( isc.nscope )
    881 					scopeok = 1;
    882 			} else {
    883 				if ( rs->sr_err == MDB_NOTFOUND )
    884 					goto notfound;
    885 			}
    886 			break;
    887 		}
    888 
    889 		/* Not in scope, ignore it */
    890 		if ( !scopeok )
    891 		{
    892 			Debug( LDAP_DEBUG_TRACE,
    893 				LDAP_XSTRING(mdb_search)
    894 				": %ld scope not okay\n",
    895 				(long) id, 0, 0 );
    896 			goto loop_continue;
    897 		}
    898 
    899 scopeok:
    900 		if ( id == base->e_id ) {
    901 			e = base;
    902 		} else {
    903 
    904 			/* get the entry */
    905 			rs->sr_err = mdb_id2edata( op, mci, id, &edata );
    906 			if ( rs->sr_err == MDB_NOTFOUND ) {
    907 notfound:
    908 				if( nsubs < ncand )
    909 					goto loop_continue;
    910 
    911 				if( !MDB_IDL_IS_RANGE(candidates) ) {
    912 					/* only complain for non-range IDLs */
    913 					Debug( LDAP_DEBUG_TRACE,
    914 						LDAP_XSTRING(mdb_search)
    915 						": candidate %ld not found\n",
    916 						(long) id, 0, 0 );
    917 				} else {
    918 					/* get the next ID from the DB */
    919 					rs->sr_err = mdb_get_nextid( mci, &cursor );
    920 					if ( rs->sr_err == MDB_NOTFOUND ) {
    921 						break;
    922 					}
    923 					if ( rs->sr_err ) {
    924 						rs->sr_err = LDAP_OTHER;
    925 						rs->sr_text = "internal error in get_nextid";
    926 						send_ldap_result( op, rs );
    927 						goto done;
    928 					}
    929 					cursor--;
    930 				}
    931 
    932 				goto loop_continue;
    933 			} else if ( rs->sr_err ) {
    934 				rs->sr_err = LDAP_OTHER;
    935 				rs->sr_text = "internal error in mdb_id2edata";
    936 				send_ldap_result( op, rs );
    937 				goto done;
    938 			}
    939 
    940 			rs->sr_err = mdb_entry_decode( op, ltid, &edata, &e );
    941 			if ( rs->sr_err ) {
    942 				rs->sr_err = LDAP_OTHER;
    943 				rs->sr_text = "internal error in mdb_entry_decode";
    944 				send_ldap_result( op, rs );
    945 				goto done;
    946 			}
    947 			e->e_id = id;
    948 			e->e_name.bv_val = NULL;
    949 			e->e_nname.bv_val = NULL;
    950 		}
    951 
    952 		if ( is_entry_subentry( e ) ) {
    953 			if( op->oq_search.rs_scope != LDAP_SCOPE_BASE ) {
    954 				if(!get_subentries_visibility( op )) {
    955 					/* only subentries are visible */
    956 					goto loop_continue;
    957 				}
    958 
    959 			} else if ( get_subentries( op ) &&
    960 				!get_subentries_visibility( op ))
    961 			{
    962 				/* only subentries are visible */
    963 				goto loop_continue;
    964 			}
    965 
    966 		} else if ( get_subentries_visibility( op )) {
    967 			/* only subentries are visible */
    968 			goto loop_continue;
    969 		}
    970 
    971 		/* aliases were already dereferenced in candidate list */
    972 		if ( op->ors_deref & LDAP_DEREF_SEARCHING ) {
    973 			/* but if the search base is an alias, and we didn't
    974 			 * deref it when finding, return it.
    975 			 */
    976 			if ( is_entry_alias(e) &&
    977 				((op->ors_deref & LDAP_DEREF_FINDING) || e != base ))
    978 			{
    979 				goto loop_continue;
    980 			}
    981 		}
    982 
    983 		if ( !manageDSAit && is_entry_glue( e )) {
    984 			goto loop_continue;
    985 		}
    986 
    987 		if (e != base) {
    988 			struct berval pdn, pndn;
    989 			char *d, *n;
    990 			int i;
    991 
    992 			/* child of base, just append RDNs to base->e_name */
    993 			if ( nsubs < ncand || isc.scopes[isc.nscope].mid == base->e_id ) {
    994 				pdn = base->e_name;
    995 				pndn = base->e_nname;
    996 			} else {
    997 				mdb_id2name( op, ltid, &isc.mc, scopes[isc.nscope].mid, &pdn, &pndn );
    998 			}
    999 			e->e_name.bv_len = pdn.bv_len;
   1000 			e->e_nname.bv_len = pndn.bv_len;
   1001 			for (i=0; i<isc.numrdns; i++) {
   1002 				e->e_name.bv_len += isc.rdns[i].bv_len + 1;
   1003 				e->e_nname.bv_len += isc.nrdns[i].bv_len + 1;
   1004 			}
   1005 			e->e_name.bv_val = op->o_tmpalloc(e->e_name.bv_len + 1, op->o_tmpmemctx);
   1006 			e->e_nname.bv_val = op->o_tmpalloc(e->e_nname.bv_len + 1, op->o_tmpmemctx);
   1007 			d = e->e_name.bv_val;
   1008 			n = e->e_nname.bv_val;
   1009 			if (nsubs < ncand) {
   1010 				/* RDNs are in top-down order */
   1011 				for (i=isc.numrdns-1; i>=0; i--) {
   1012 					memcpy(d, isc.rdns[i].bv_val, isc.rdns[i].bv_len);
   1013 					d += isc.rdns[i].bv_len;
   1014 					*d++ = ',';
   1015 					memcpy(n, isc.nrdns[i].bv_val, isc.nrdns[i].bv_len);
   1016 					n += isc.nrdns[i].bv_len;
   1017 					*n++ = ',';
   1018 				}
   1019 			} else {
   1020 				/* RDNs are in bottom-up order */
   1021 				for (i=0; i<isc.numrdns; i++) {
   1022 					memcpy(d, isc.rdns[i].bv_val, isc.rdns[i].bv_len);
   1023 					d += isc.rdns[i].bv_len;
   1024 					*d++ = ',';
   1025 					memcpy(n, isc.nrdns[i].bv_val, isc.nrdns[i].bv_len);
   1026 					n += isc.nrdns[i].bv_len;
   1027 					*n++ = ',';
   1028 				}
   1029 			}
   1030 
   1031 			if (pdn.bv_len) {
   1032 				memcpy(d, pdn.bv_val, pdn.bv_len+1);
   1033 				memcpy(n, pndn.bv_val, pndn.bv_len+1);
   1034 			} else {
   1035 				*--d = '\0';
   1036 				*--n = '\0';
   1037 				e->e_name.bv_len--;
   1038 				e->e_nname.bv_len--;
   1039 			}
   1040 			if (pndn.bv_val != base->e_nname.bv_val) {
   1041 				op->o_tmpfree(pndn.bv_val, op->o_tmpmemctx);
   1042 				op->o_tmpfree(pdn.bv_val, op->o_tmpmemctx);
   1043 			}
   1044 		}
   1045 
   1046 		/*
   1047 		 * if it's a referral, add it to the list of referrals. only do
   1048 		 * this for non-base searches, and don't check the filter
   1049 		 * explicitly here since it's only a candidate anyway.
   1050 		 */
   1051 		if ( !manageDSAit && op->oq_search.rs_scope != LDAP_SCOPE_BASE
   1052 			&& is_entry_referral( e ) )
   1053 		{
   1054 			BerVarray erefs = get_entry_referrals( op, e );
   1055 			rs->sr_ref = referral_rewrite( erefs, &e->e_name, NULL,
   1056 				op->oq_search.rs_scope == LDAP_SCOPE_ONELEVEL
   1057 					? LDAP_SCOPE_BASE : LDAP_SCOPE_SUBTREE );
   1058 
   1059 			rs->sr_entry = e;
   1060 			rs->sr_flags = 0;
   1061 
   1062 			send_search_reference( op, rs );
   1063 
   1064 			if (e != base)
   1065 				mdb_entry_return( op, e );
   1066 			rs->sr_entry = NULL;
   1067 			e = NULL;
   1068 
   1069 			ber_bvarray_free( rs->sr_ref );
   1070 			ber_bvarray_free( erefs );
   1071 			rs->sr_ref = NULL;
   1072 
   1073 			goto loop_continue;
   1074 		}
   1075 
   1076 		/* if it matches the filter and scope, send it */
   1077 		rs->sr_err = test_filter( op, e, op->oq_search.rs_filter );
   1078 
   1079 		if ( rs->sr_err == LDAP_COMPARE_TRUE ) {
   1080 			/* check size limit */
   1081 			if ( get_pagedresults(op) > SLAP_CONTROL_IGNORED ) {
   1082 				if ( rs->sr_nentries >= ((PagedResultsState *)op->o_pagedresults_state)->ps_size ) {
   1083 					if (e != base)
   1084 						mdb_entry_return( op, e );
   1085 					e = NULL;
   1086 					send_paged_response( op, rs, &lastid, tentries );
   1087 					goto done;
   1088 				}
   1089 				lastid = id;
   1090 			}
   1091 
   1092 			if (e) {
   1093 				/* safe default */
   1094 				rs->sr_attrs = op->oq_search.rs_attrs;
   1095 				rs->sr_operational_attrs = NULL;
   1096 				rs->sr_ctrls = NULL;
   1097 				rs->sr_entry = e;
   1098 				RS_ASSERT( e->e_private != NULL );
   1099 				rs->sr_flags = 0;
   1100 				rs->sr_err = LDAP_SUCCESS;
   1101 				rs->sr_err = send_search_entry( op, rs );
   1102 				rs->sr_attrs = NULL;
   1103 				rs->sr_entry = NULL;
   1104 				if (e != base)
   1105 					mdb_entry_return( op, e );
   1106 				e = NULL;
   1107 
   1108 				switch ( rs->sr_err ) {
   1109 				case LDAP_SUCCESS:	/* entry sent ok */
   1110 					break;
   1111 				default:		/* entry not sent */
   1112 					break;
   1113 				case LDAP_BUSY:
   1114 					send_ldap_result( op, rs );
   1115 					goto done;
   1116 				case LDAP_UNAVAILABLE:
   1117 				case LDAP_SIZELIMIT_EXCEEDED:
   1118 					if ( rs->sr_err == LDAP_SIZELIMIT_EXCEEDED ) {
   1119 						rs->sr_ref = rs->sr_v2ref;
   1120 						send_ldap_result( op, rs );
   1121 						rs->sr_err = LDAP_SUCCESS;
   1122 
   1123 					} else {
   1124 						rs->sr_err = LDAP_OTHER;
   1125 					}
   1126 					goto done;
   1127 				}
   1128 			}
   1129 
   1130 		} else {
   1131 			Debug( LDAP_DEBUG_TRACE,
   1132 				LDAP_XSTRING(mdb_search)
   1133 				": %ld does not match filter\n",
   1134 				(long) id, 0, 0 );
   1135 		}
   1136 
   1137 loop_continue:
   1138 		if ( moi == &opinfo && !wwctx.flag && mdb->mi_rtxn_size ) {
   1139 			wwctx.nentries++;
   1140 			if ( wwctx.nentries >= mdb->mi_rtxn_size ) {
   1141 				MDB_envinfo ei;
   1142 				wwctx.nentries = 0;
   1143 				mdb_env_info(mdb->mi_dbenv, &ei);
   1144 				if ( ei.me_last_txnid > mdb_txn_id( ltid ))
   1145 					mdb_rtxn_snap( op, &wwctx );
   1146 			}
   1147 		}
   1148 		if ( wwctx.flag ) {
   1149 			rs->sr_err = mdb_waitfixup( op, &wwctx, mci, mcd, &isc );
   1150 			if ( rs->sr_err ) {
   1151 				send_ldap_result( op, rs );
   1152 				goto done;
   1153 			}
   1154 		}
   1155 
   1156 		if( e != NULL ) {
   1157 			if ( e != base )
   1158 				mdb_entry_return( op, e );
   1159 			RS_ASSERT( rs->sr_entry == NULL );
   1160 			e = NULL;
   1161 			rs->sr_entry = NULL;
   1162 		}
   1163 
   1164 		if ( nsubs < ncand ) {
   1165 			int rc = mdb_dn2id_walk( op, &isc );
   1166 			if (rc) {
   1167 				id = NOID;
   1168 				/* We got to the end of a subtree. If there are any
   1169 				 * alias scopes left, search them too.
   1170 				 */
   1171 				while (iscopes[0] && cscope < iscopes[0]) {
   1172 					cscope++;
   1173 					isc.id = iscopes[cscope];
   1174 					if ( base )
   1175 						mdb_entry_return( op, base );
   1176 					rs->sr_err = mdb_id2entry(op, mci, isc.id, &base);
   1177 					if ( !rs->sr_err ) {
   1178 						mdb_id2name( op, ltid, &isc.mc, isc.id, &base->e_name, &base->e_nname );
   1179 						isc.numrdns = 0;
   1180 						if (isc.oscope == LDAP_SCOPE_ONELEVEL)
   1181 							isc.oscope = LDAP_SCOPE_BASE;
   1182 						rc = mdb_dn2id_walk( op, &isc );
   1183 						if ( !rc ) {
   1184 							id = isc.id;
   1185 							break;
   1186 						}
   1187 					}
   1188 				}
   1189 			} else
   1190 				id = isc.id;
   1191 		} else {
   1192 			id = mdb_idl_next( candidates, &cursor );
   1193 		}
   1194 	}
   1195 
   1196 nochange:
   1197 	rs->sr_ctrls = NULL;
   1198 	rs->sr_ref = rs->sr_v2ref;
   1199 	rs->sr_err = (rs->sr_v2ref == NULL) ? LDAP_SUCCESS : LDAP_REFERRAL;
   1200 	rs->sr_rspoid = NULL;
   1201 	if ( get_pagedresults(op) > SLAP_CONTROL_IGNORED ) {
   1202 		send_paged_response( op, rs, NULL, 0 );
   1203 	} else {
   1204 		send_ldap_result( op, rs );
   1205 	}
   1206 
   1207 	rs->sr_err = LDAP_SUCCESS;
   1208 
   1209 done:
   1210 	if ( cb.sc_private ) {
   1211 		/* remove our writewait callback */
   1212 		slap_callback **scp = &op->o_callback;
   1213 		while ( *scp ) {
   1214 			if ( *scp == &cb ) {
   1215 				*scp = cb.sc_next;
   1216 				cb.sc_private = NULL;
   1217 				break;
   1218 			}
   1219 		}
   1220 	}
   1221 	mdb_cursor_close( mcd );
   1222 	mdb_cursor_close( mci );
   1223 	if ( moi == &opinfo ) {
   1224 		mdb_txn_reset( moi->moi_txn );
   1225 		LDAP_SLIST_REMOVE( &op->o_extra, &moi->moi_oe, OpExtra, oe_next );
   1226 	} else {
   1227 		moi->moi_ref--;
   1228 	}
   1229 	if( rs->sr_v2ref ) {
   1230 		ber_bvarray_free( rs->sr_v2ref );
   1231 		rs->sr_v2ref = NULL;
   1232 	}
   1233 	if (base)
   1234 		mdb_entry_return( op, base );
   1235 	scope_chunk_ret( op, scopes );
   1236 
   1237 	return rs->sr_err;
   1238 }
   1239 
   1240 
   1241 static int base_candidate(
   1242 	BackendDB	*be,
   1243 	Entry	*e,
   1244 	ID		*ids )
   1245 {
   1246 	Debug(LDAP_DEBUG_ARGS, "base_candidates: base: \"%s\" (0x%08lx)\n",
   1247 		e->e_nname.bv_val, (long) e->e_id, 0);
   1248 
   1249 	ids[0] = 1;
   1250 	ids[1] = e->e_id;
   1251 	return 0;
   1252 }
   1253 
   1254 /* Look for "objectClass Present" in this filter.
   1255  * Also count depth of filter tree while we're at it.
   1256  */
   1257 static int oc_filter(
   1258 	Filter *f,
   1259 	int cur,
   1260 	int *max )
   1261 {
   1262 	int rc = 0;
   1263 
   1264 	assert( f != NULL );
   1265 
   1266 	if( cur > *max ) *max = cur;
   1267 
   1268 	switch( f->f_choice ) {
   1269 	case LDAP_FILTER_PRESENT:
   1270 		if (f->f_desc == slap_schema.si_ad_objectClass) {
   1271 			rc = 1;
   1272 		}
   1273 		break;
   1274 
   1275 	case LDAP_FILTER_AND:
   1276 	case LDAP_FILTER_OR:
   1277 		cur++;
   1278 		for ( f=f->f_and; f; f=f->f_next ) {
   1279 			(void) oc_filter(f, cur, max);
   1280 		}
   1281 		break;
   1282 
   1283 	default:
   1284 		break;
   1285 	}
   1286 	return rc;
   1287 }
   1288 
   1289 static void search_stack_free( void *key, void *data )
   1290 {
   1291 	ber_memfree_x(data, NULL);
   1292 }
   1293 
   1294 static void *search_stack( Operation *op )
   1295 {
   1296 	struct mdb_info *mdb = (struct mdb_info *) op->o_bd->be_private;
   1297 	void *ret = NULL;
   1298 
   1299 	if ( op->o_threadctx ) {
   1300 		ldap_pvt_thread_pool_getkey( op->o_threadctx, (void *)search_stack,
   1301 			&ret, NULL );
   1302 	} else {
   1303 		ret = mdb->mi_search_stack;
   1304 	}
   1305 
   1306 	if ( !ret ) {
   1307 		ret = ch_malloc( mdb->mi_search_stack_depth * MDB_IDL_UM_SIZE
   1308 			* sizeof( ID ) );
   1309 		if ( op->o_threadctx ) {
   1310 			ldap_pvt_thread_pool_setkey( op->o_threadctx, (void *)search_stack,
   1311 				ret, search_stack_free, NULL, NULL );
   1312 		} else {
   1313 			mdb->mi_search_stack = ret;
   1314 		}
   1315 	}
   1316 	return ret;
   1317 }
   1318 
   1319 static int search_candidates(
   1320 	Operation *op,
   1321 	SlapReply *rs,
   1322 	Entry *e,
   1323 	IdScopes *isc,
   1324 	MDB_cursor *mci,
   1325 	ID	*ids,
   1326 	ID *stack )
   1327 {
   1328 	struct mdb_info *mdb = (struct mdb_info *) op->o_bd->be_private;
   1329 	int rc, depth = 1;
   1330 	Filter		*f, rf, xf, nf, sf;
   1331 	AttributeAssertion aa_ref = ATTRIBUTEASSERTION_INIT;
   1332 	AttributeAssertion aa_subentry = ATTRIBUTEASSERTION_INIT;
   1333 
   1334 	/*
   1335 	 * This routine takes as input a filter (user-filter)
   1336 	 * and rewrites it as follows:
   1337 	 *	(&(scope=DN)[(objectClass=subentry)]
   1338 	 *		(|[(objectClass=referral)](user-filter))
   1339 	 */
   1340 
   1341 	Debug(LDAP_DEBUG_TRACE,
   1342 		"search_candidates: base=\"%s\" (0x%08lx) scope=%d\n",
   1343 		e->e_nname.bv_val, (long) e->e_id, op->oq_search.rs_scope );
   1344 
   1345 	f = op->oq_search.rs_filter;
   1346 
   1347 	/* If the user's filter uses objectClass=*,
   1348 	 * these clauses are redundant.
   1349 	 */
   1350 	if (!oc_filter(op->oq_search.rs_filter, 1, &depth)
   1351 		&& !get_subentries_visibility(op)) {
   1352 		if( !get_manageDSAit(op) && !get_domainScope(op) ) {
   1353 			/* match referral objects */
   1354 			struct berval bv_ref = BER_BVC( "referral" );
   1355 			rf.f_choice = LDAP_FILTER_EQUALITY;
   1356 			rf.f_ava = &aa_ref;
   1357 			rf.f_av_desc = slap_schema.si_ad_objectClass;
   1358 			rf.f_av_value = bv_ref;
   1359 			rf.f_next = f;
   1360 			xf.f_or = &rf;
   1361 			xf.f_choice = LDAP_FILTER_OR;
   1362 			xf.f_next = NULL;
   1363 			f = &xf;
   1364 			depth++;
   1365 		}
   1366 	}
   1367 
   1368 	if( get_subentries_visibility( op ) ) {
   1369 		struct berval bv_subentry = BER_BVC( "subentry" );
   1370 		sf.f_choice = LDAP_FILTER_EQUALITY;
   1371 		sf.f_ava = &aa_subentry;
   1372 		sf.f_av_desc = slap_schema.si_ad_objectClass;
   1373 		sf.f_av_value = bv_subentry;
   1374 		sf.f_next = f;
   1375 		nf.f_choice = LDAP_FILTER_AND;
   1376 		nf.f_and = &sf;
   1377 		nf.f_next = NULL;
   1378 		f = &nf;
   1379 		depth++;
   1380 	}
   1381 
   1382 	/* Allocate IDL stack, plus 1 more for former tmp */
   1383 	if ( depth+1 > mdb->mi_search_stack_depth ) {
   1384 		stack = ch_malloc( (depth + 1) * MDB_IDL_UM_SIZE * sizeof( ID ) );
   1385 	}
   1386 
   1387 	if( op->ors_deref & LDAP_DEREF_SEARCHING ) {
   1388 		rc = search_aliases( op, rs, e->e_id, isc, mci, stack );
   1389 	} else {
   1390 		rc = LDAP_SUCCESS;
   1391 	}
   1392 
   1393 	if ( rc == LDAP_SUCCESS ) {
   1394 		rc = mdb_filter_candidates( op, isc->mt, f, ids,
   1395 			stack, stack+MDB_IDL_UM_SIZE );
   1396 	}
   1397 
   1398 	if ( depth+1 > mdb->mi_search_stack_depth ) {
   1399 		ch_free( stack );
   1400 	}
   1401 
   1402 	if( rc ) {
   1403 		Debug(LDAP_DEBUG_TRACE,
   1404 			"mdb_search_candidates: failed (rc=%d)\n",
   1405 			rc, NULL, NULL );
   1406 
   1407 	} else {
   1408 		Debug(LDAP_DEBUG_TRACE,
   1409 			"mdb_search_candidates: id=%ld first=%ld last=%ld\n",
   1410 			(long) ids[0],
   1411 			(long) MDB_IDL_FIRST(ids),
   1412 			(long) MDB_IDL_LAST(ids) );
   1413 	}
   1414 
   1415 	return rc;
   1416 }
   1417 
   1418 static int
   1419 parse_paged_cookie( Operation *op, SlapReply *rs )
   1420 {
   1421 	int		rc = LDAP_SUCCESS;
   1422 	PagedResultsState *ps = op->o_pagedresults_state;
   1423 
   1424 	/* this function must be invoked only if the pagedResults
   1425 	 * control has been detected, parsed and partially checked
   1426 	 * by the frontend */
   1427 	assert( get_pagedresults( op ) > SLAP_CONTROL_IGNORED );
   1428 
   1429 	/* cookie decoding/checks deferred to backend... */
   1430 	if ( ps->ps_cookieval.bv_len ) {
   1431 		PagedResultsCookie reqcookie;
   1432 		if( ps->ps_cookieval.bv_len != sizeof( reqcookie ) ) {
   1433 			/* bad cookie */
   1434 			rs->sr_text = "paged results cookie is invalid";
   1435 			rc = LDAP_PROTOCOL_ERROR;
   1436 			goto done;
   1437 		}
   1438 
   1439 		AC_MEMCPY( &reqcookie, ps->ps_cookieval.bv_val, sizeof( reqcookie ));
   1440 
   1441 		if ( reqcookie > ps->ps_cookie ) {
   1442 			/* bad cookie */
   1443 			rs->sr_text = "paged results cookie is invalid";
   1444 			rc = LDAP_PROTOCOL_ERROR;
   1445 			goto done;
   1446 
   1447 		} else if ( reqcookie < ps->ps_cookie ) {
   1448 			rs->sr_text = "paged results cookie is invalid or old";
   1449 			rc = LDAP_UNWILLING_TO_PERFORM;
   1450 			goto done;
   1451 		}
   1452 
   1453 	} else {
   1454 		/* we're going to use ps_cookie */
   1455 		op->o_conn->c_pagedresults_state.ps_cookie = 0;
   1456 	}
   1457 
   1458 done:;
   1459 
   1460 	return rc;
   1461 }
   1462 
   1463 static void
   1464 send_paged_response(
   1465 	Operation	*op,
   1466 	SlapReply	*rs,
   1467 	ID		*lastid,
   1468 	int		tentries )
   1469 {
   1470 	LDAPControl	*ctrls[2];
   1471 	BerElementBuffer berbuf;
   1472 	BerElement	*ber = (BerElement *)&berbuf;
   1473 	PagedResultsCookie respcookie;
   1474 	struct berval cookie;
   1475 
   1476 	Debug(LDAP_DEBUG_ARGS,
   1477 		"send_paged_response: lastid=0x%08lx nentries=%d\n",
   1478 		lastid ? *lastid : 0, rs->sr_nentries, NULL );
   1479 
   1480 	ctrls[1] = NULL;
   1481 
   1482 	ber_init2( ber, NULL, LBER_USE_DER );
   1483 
   1484 	if ( lastid ) {
   1485 		respcookie = ( PagedResultsCookie )(*lastid);
   1486 		cookie.bv_len = sizeof( respcookie );
   1487 		cookie.bv_val = (char *)&respcookie;
   1488 
   1489 	} else {
   1490 		respcookie = ( PagedResultsCookie )0;
   1491 		BER_BVSTR( &cookie, "" );
   1492 	}
   1493 
   1494 	op->o_conn->c_pagedresults_state.ps_cookie = respcookie;
   1495 	op->o_conn->c_pagedresults_state.ps_count =
   1496 		((PagedResultsState *)op->o_pagedresults_state)->ps_count +
   1497 		rs->sr_nentries;
   1498 
   1499 	/* return size of 0 -- no estimate */
   1500 	ber_printf( ber, "{iO}", 0, &cookie );
   1501 
   1502 	ctrls[0] = op->o_tmpalloc( sizeof(LDAPControl), op->o_tmpmemctx );
   1503 	if ( ber_flatten2( ber, &ctrls[0]->ldctl_value, 0 ) == -1 ) {
   1504 		goto done;
   1505 	}
   1506 
   1507 	ctrls[0]->ldctl_oid = LDAP_CONTROL_PAGEDRESULTS;
   1508 	ctrls[0]->ldctl_iscritical = 0;
   1509 
   1510 	slap_add_ctrls( op, rs, ctrls );
   1511 	rs->sr_err = LDAP_SUCCESS;
   1512 	send_ldap_result( op, rs );
   1513 
   1514 done:
   1515 	(void) ber_free_buf( ber );
   1516 }
   1517