summaryrefslogtreecommitdiffstats
path: root/source4/dsdb/samdb/ldb_modules/vlv_pagination.c
blob: b389d3fd4f0b6c2935c0fa98a51b13458a340396 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
/*
   ldb database library

   Copyright (C) Simo Sorce  2005-2008
   Copyright (C) Catalyst IT 2016

     ** NOTE! The following LGPL license applies to the ldb
     ** library. This does NOT imply that all of Samba is released
     ** under the LGPL

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 3 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/

/*
 *  Name: vlv_pagination
 *
 *  Component: ldb vlv pagination control module
 *
 *  Description: this module caches a complete search and sends back
 *  		 results in chunks as asked by the client
 *
 *  Originally based on paged_results.c by Simo Sorce
 *  Modified by Douglas Bagnall and Garming Sam for Catalyst.
 */

#include "includes.h"
#include "auth/auth.h"
#include <ldb.h>
#include "dsdb/samdb/samdb.h"
#include "libcli/security/security.h"
#include "libcli/ldap/ldap_errors.h"
#include <ldb.h>
#include "replace.h"
#include "system/filesys.h"
#include "system/time.h"
#include "ldb_module.h"
#include "dsdb/samdb/samdb.h"

#include "dsdb/common/util.h"
#include "lib/util/binsearch.h"

/* This is the number of concurrent searches per connection to cache. */
#define VLV_N_SEARCHES 5


struct results_store {
	uint32_t contextId;
	time_t timestamp;

	struct GUID *results;
	size_t num_entries;
	size_t result_array_size;

	struct referral_store *first_ref;
	struct referral_store *last_ref;

	struct ldb_control **controls;
	struct ldb_control **down_controls;
	struct ldb_vlv_req_control *vlv_details;
	struct ldb_server_sort_control *sort_details;
};

struct private_data {
	uint32_t next_free_id;
	struct results_store **store;
	int n_stores;
};


struct vlv_context {
	struct ldb_module *module;
	struct ldb_request *req;
	struct results_store *store;
	struct ldb_control **controls;
	struct private_data *priv;
};


static struct results_store *new_store(struct private_data *priv)
{
	struct results_store *store;
	int i;
	int best = 0;
	time_t oldest = TIME_T_MAX;
	for (i = 0; i < priv->n_stores; i++) {
		if (priv->store[i] == NULL) {
			best = i;
			break;
		} else if (priv->store[i]->timestamp < oldest){
			best = i;
			oldest = priv->store[i]->timestamp;
		}
	}

	store = talloc_zero(priv, struct results_store);
	if (store == NULL) {
		return NULL;
	}
	if (priv->store[best] != NULL) {
		TALLOC_FREE(priv->store[best]);
	}
	priv->store[best] = store;
	store->timestamp = time(NULL);
	return store;
}


struct vlv_sort_context {
	struct ldb_context *ldb;
	ldb_attr_comparison_t comparison_fn;
	const char *attr;
	struct vlv_context *ac;
	int status;
	struct ldb_val value;
};


/* Referrals are temporarily stored in a linked list */
struct referral_store {
	char *ref;
	struct referral_store *next;
};

/*
  search for attrs on one DN, by the GUID of the DN, with true
  LDB controls
 */

static int vlv_search_by_dn_guid(struct ldb_module *module,
				 struct vlv_context *ac,
				 struct ldb_result **result,
				 const struct GUID *guid,
				 const char * const *attrs)
{
	struct ldb_dn *dn;
	struct ldb_request *req;
	struct ldb_result *res;
	int ret;
	struct GUID_txt_buf guid_str;
	struct ldb_control **controls = ac->store->down_controls;
	struct ldb_context *ldb = ldb_module_get_ctx(module);

	dn = ldb_dn_new_fmt(ac, ldb, "<GUID=%s>",
			    GUID_buf_string(guid, &guid_str));
	if (dn == NULL) {
		return ldb_oom(ldb);
	}

	res = talloc_zero(ac, struct ldb_result);
	if (res == NULL) {
		return ldb_oom(ldb);
	}

	ret = ldb_build_search_req(&req, ldb, ac,
				   dn,
				   LDB_SCOPE_BASE,
				   NULL,
				   attrs,
				   controls,
				   res,
				   ldb_search_default_callback,
				   ac->req);
	if (ret != LDB_SUCCESS) {
		talloc_free(res);
		return ret;
	}

	ret = ldb_request(ldb, req);
	if (ret == LDB_SUCCESS) {
		ret = ldb_wait(req->handle, LDB_WAIT_ALL);
	}

	talloc_free(req);
	if (ret != LDB_SUCCESS) {
		talloc_free(res);
		return ret;
	}

	*result = res;
	return ret;
}


static int save_referral(struct results_store *store, char *ref)
{
	struct referral_store *node = talloc(store,
					     struct referral_store);
	if (node == NULL) {
		return LDB_ERR_OPERATIONS_ERROR;
	}
	node->next = NULL;
	node->ref = talloc_steal(node, ref);

	if (store->first_ref == NULL) {
		store->first_ref = node;
	} else {
		store->last_ref->next = node;
	}
	store->last_ref = node;
	return LDB_SUCCESS;
}

static int send_referrals(struct results_store *store,
			  struct ldb_request *req)
{
	int ret;
	struct referral_store *node;
	while (store->first_ref != NULL) {
		node = store->first_ref;
		ret = ldb_module_send_referral(req, node->ref);
		if (ret != LDB_SUCCESS) {
			return ret;
		}
		store->first_ref = node->next;
		talloc_free(node);
	}
	return LDB_SUCCESS;
}


/* vlv_value_compare() is used in a binary search */

static int vlv_value_compare(struct vlv_sort_context *target,
			     struct GUID *guid)
{
	struct ldb_result *result = NULL;
	struct ldb_message_element *el = NULL;
	struct vlv_context *ac = target->ac;
	int ret;
	const char *attrs[2] = {
		target->attr,
		NULL
	};

	ret = vlv_search_by_dn_guid(ac->module, ac, &result, guid, attrs);

	if (ret != LDB_SUCCESS) {
		target->status = ret;
		/* returning 0 ends the search. */
		return 0;
	}

	el = ldb_msg_find_element(result->msgs[0], target->attr);
	return target->comparison_fn(target->ldb, ac,
				     &target->value, &el->values[0]);

}

/* The same as vlv_value_compare() but sorting in the opposite direction. */
static int vlv_value_compare_rev(struct vlv_sort_context *target,
			     struct GUID *guid)
{
	return -vlv_value_compare(target, guid);
}



/* Convert a "greater than or equal to" VLV query into an index. This is
   zero-based, so one less than the equivalent VLV offset query.

   If the query value is greater than (or less than in the reverse case) all
   the items, An index just beyond the last position is used.

   If an error occurs during the search for the index, we stash it in the
   status argument.
 */

static int vlv_gt_eq_to_index(struct vlv_context *ac,
			      struct GUID *guid_array,
			      struct ldb_vlv_req_control *vlv_details,
			      struct ldb_server_sort_control *sort_details,
			      int *status)
{
	/* this has a >= comparison string, which needs to be
	 * converted into indices.
	 */
	size_t len = ac->store->num_entries;
	struct ldb_context *ldb;
	const struct ldb_schema_attribute *a;
	struct GUID *result = NULL;
	struct vlv_sort_context context;
	struct ldb_val value = {
		.data = (uint8_t *)vlv_details->match.gtOrEq.value,
		.length = vlv_details->match.gtOrEq.value_len
	};
	ldb = ldb_module_get_ctx(ac->module);
	a = ldb_schema_attribute_by_name(ldb, sort_details->attributeName);

	context = (struct vlv_sort_context){
		.ldb = ldb,
		.comparison_fn = a->syntax->comparison_fn,
		.attr = sort_details->attributeName,
		.ac = ac,
		.status = LDB_SUCCESS,
		.value = value
	};

	if (sort_details->reverse) {
		/* when the sort is reversed, "gtOrEq" means
		   "less than or equal" */
		BINARY_ARRAY_SEARCH_GTE(guid_array, len, &context,
					vlv_value_compare_rev,
					result, result);
	} else {
		BINARY_ARRAY_SEARCH_GTE(guid_array, len, &context,
					vlv_value_compare,
					result, result);
	}
	if (context.status != LDB_SUCCESS) {
		*status = context.status;
		return len;
	}
	*status = LDB_SUCCESS;

	if (result == NULL) {
		/* the target is beyond the end of the array */
		return len;
	}
	return result - guid_array;

}

/* return the zero-based index into the sorted results, or -1 on error.

   The VLV index is one-base, so one greater than this.
 */

static int vlv_calc_real_offset(int offset, int denominator, int n_entries)
{
	double fraction;

	/* An offset of 0 (or less) is an error, unless the denominator is
	   also zero. */
	if (offset <= 0 && denominator != 0) {
		return -1;
	}

	/* a denominator of zero means the server should use the estimated
	   number of entries. */
	if (denominator == 0) {
		if (offset == 0) {
                        /* 0/0 means the last one */
			return n_entries - 1;
		}
		denominator = n_entries;
	}

	if (denominator == 1) {
		/* The 1/1 case means the LAST index.
		   Strangely, for n > 1, n/1 means the FIRST index.
		*/
		if (offset == 1) {
			return n_entries - 1;
		}
		return 0;
	}

	if (offset >= denominator) {
		/* we want the last one */
		return n_entries - 1;
	}
	/* if the denominator is exactly the number of entries, the offset is
	   already correct. */

	if (denominator == n_entries) {
		return offset - 1;
	}

	/* The following formula was discovered by probing Windows. */
	fraction = (offset - 1.0) / (denominator - 1.0);
	return (int)(fraction * (n_entries - 1.0) + 0.5);
}


/* vlv_results() is called when there is a valid contextID -- meaning the search
   has been prepared earlier and saved -- or by vlv_search_callback() when a
   search has just been completed. */

static int vlv_results(struct vlv_context *ac, struct ldb_reply *ares)
{
	struct ldb_extended *response = (ares != NULL ? ares->response : NULL);
	struct ldb_vlv_resp_control *vlv;
	unsigned int num_ctrls;
	int ret, i, first_i, last_i;
	struct ldb_vlv_req_control *vlv_details;
	struct ldb_server_sort_control *sort_details;
	int target = 0;

	if (ac->store == NULL) {
		ret = LDB_ERR_OPERATIONS_ERROR;
		return ldb_module_done(
			ac->req, ac->controls, response, ret);
	}

	if (ac->store->first_ref) {
		/* There is no right place to put references in the sorted
		   results, so we send them as soon as possible.
		*/
		ret = send_referrals(ac->store, ac->req);
		if (ret != LDB_SUCCESS) {
			/*
			 * send_referrals will have called ldb_module_done
			 * if there was an error.
			 */
			return ret;
		}
	}

	vlv_details = ac->store->vlv_details;
	sort_details = ac->store->sort_details;

	if (ac->store->num_entries != 0) {
		if (vlv_details->type == 1) {
			target = vlv_gt_eq_to_index(ac, ac->store->results,
						    vlv_details,
						    sort_details, &ret);
			if (ret != LDB_SUCCESS) {
				return ldb_module_done(
					ac->req,
					ac->controls,
					response,
					ret);
			}
		} else {
			target = vlv_calc_real_offset(vlv_details->match.byOffset.offset,
						      vlv_details->match.byOffset.contentCount,
						      ac->store->num_entries);
			if (target == -1) {
				ret = LDB_ERR_OPERATIONS_ERROR;
				return ldb_module_done(
					ac->req,
					ac->controls,
					response,
					ret);
			}
		}

		/* send the results */
		first_i = MAX(target - vlv_details->beforeCount, 0);
		last_i = MIN(target + vlv_details->afterCount,
			     ac->store->num_entries - 1);

		for (i = first_i; i <= last_i; i++) {
			struct ldb_result *result = NULL;
			struct GUID *guid = &ac->store->results[i];

			ret = vlv_search_by_dn_guid(ac->module, ac, &result, guid,
						    ac->req->op.search.attrs);

			if (ret == LDAP_NO_SUCH_OBJECT
			    || result->count != 1) {
				/*
				 * The thing isn't there, which we quietly
				 * ignore and go on to send an extra one
				 * instead.
				 *
				 * result->count == 0 or > 1 can only
				 * happen if ASQ (which breaks all the
				 * rules) is somehow invoked (as this
				 * is a BASE search).
				 *
				 * (We skip the ASQ cookie for the
				 * GUID searches)
				 */
				if (last_i < ac->store->num_entries - 1) {
					last_i++;
				}
				continue;
			} else if (ret != LDB_SUCCESS) {
				return ldb_module_done(
					ac->req,
					ac->controls,
					response,
					ret);
			}

			ret = ldb_module_send_entry(ac->req, result->msgs[0],
						    NULL);
			if (ret != LDB_SUCCESS) {
				/*
				 * ldb_module_send_entry will have called
				 * ldb_module_done if there was an error
				 */
				return ret;
			}
		}
	} else {
		target = -1;
	}

	/* return result done */
	num_ctrls = 1;
	i = 0;

	if (ac->store->controls != NULL) {
		while (ac->store->controls[i]){
			i++; /* counting */
		}
		num_ctrls += i;
	}

	ac->controls = talloc_array(ac, struct ldb_control *, num_ctrls + 1);
	if (ac->controls == NULL) {
		ret = LDB_ERR_OPERATIONS_ERROR;
		return ldb_module_done(
			ac->req, ac->controls, response, ret);
	}
	ac->controls[num_ctrls] = NULL;

	for (i = 0; i < (num_ctrls -1); i++) {
		ac->controls[i] = talloc_reference(ac->controls, ac->store->controls[i]);
	}

	ac->controls[i] = talloc(ac->controls, struct ldb_control);
	if (ac->controls[i] == NULL) {
		ret = LDB_ERR_OPERATIONS_ERROR;
		return ldb_module_done(
			ac->req, ac->controls, response, ret);
	}

	ac->controls[i]->oid = talloc_strdup(ac->controls[i],
					     LDB_CONTROL_VLV_RESP_OID);
	if (ac->controls[i]->oid == NULL) {
		ret = LDB_ERR_OPERATIONS_ERROR;
		return ldb_module_done(
			ac->req, ac->controls, response, ret);
	}

	ac->controls[i]->critical = 0;

	vlv = talloc(ac->controls[i], struct ldb_vlv_resp_control);
	if (vlv == NULL) {
		ret = LDB_ERR_OPERATIONS_ERROR;
		return ldb_module_done(
			ac->req, ac->controls, response, ret);
	}
	ac->controls[i]->data = vlv;

	ac->store->timestamp = time(NULL);

	ac->store->contextId = ac->priv->next_free_id;
	ac->priv->next_free_id++;
	vlv->contextId = talloc_memdup(vlv, &ac->store->contextId, sizeof(uint32_t));
	vlv->ctxid_len = sizeof(uint32_t);
	vlv->vlv_result = 0;
	vlv->contentCount = ac->store->num_entries;
	if (target >= 0) {
		vlv->targetPosition = target + 1;
	} else if (vlv_details->type == 1) {
		vlv->targetPosition = ac->store->num_entries + 1;
	} else {
		vlv->targetPosition = 0;
	}
	return LDB_SUCCESS;
}


/* vlv_search_callback() collects GUIDs found by the original search */

static int vlv_search_callback(struct ldb_request *req, struct ldb_reply *ares)
{
	struct vlv_context *ac;
	struct results_store *store;
	int ret;

	ac = talloc_get_type(req->context, struct vlv_context);
	store = ac->store;

	if (!ares) {
		return ldb_module_done(ac->req, NULL, NULL,
					LDB_ERR_OPERATIONS_ERROR);
	}
	if (ares->error != LDB_SUCCESS) {
		return ldb_module_done(ac->req, ares->controls,
					ares->response, ares->error);
	}

	switch (ares->type) {
	case LDB_REPLY_ENTRY:
		if (store->results == NULL) {
			store->num_entries = 0;
			store->result_array_size = 16;
			store->results = talloc_array(store, struct GUID,
						      store->result_array_size);
			if (store->results == NULL) {
				return ldb_module_done(ac->req, NULL, NULL,
						       LDB_ERR_OPERATIONS_ERROR);
			}
		} else if (store->num_entries == store->result_array_size) {
			store->result_array_size *= 2;
			store->results = talloc_realloc(store, store->results,
							struct GUID,
							store->result_array_size);
			if (store->results == NULL) {
				return ldb_module_done(ac->req, NULL, NULL,
						       LDB_ERR_OPERATIONS_ERROR);
			}
		}
		store->results[store->num_entries] = \
			samdb_result_guid(ares->message, "objectGUID");
		store->num_entries++;
		break;

	case LDB_REPLY_REFERRAL:
		ret = save_referral(store, ares->referral);
		if (ret != LDB_SUCCESS) {
			return ldb_module_done(ac->req, NULL, NULL, ret);
		}
		break;

	case LDB_REPLY_DONE:
		if (store->num_entries != 0) {
			store->results = talloc_realloc(store, store->results,
							struct GUID,
							store->num_entries);
			if (store->results == NULL) {
				return ldb_module_done(ac->req, NULL, NULL,
						       LDB_ERR_OPERATIONS_ERROR);
			}
		}
		store->result_array_size = store->num_entries;

		ac->store->controls = talloc_move(ac->store, &ares->controls);
		ret = vlv_results(ac, ares);
		if (ret != LDB_SUCCESS) {
			/* vlv_results will have called ldb_module_done
			 * if there was an error.
			 */
			return ret;
		}
		return ldb_module_done(ac->req, ac->controls,
					ares->response, ret);
	}

	return LDB_SUCCESS;
}

static int copy_search_details(struct results_store *store,
			       struct ldb_vlv_req_control *vlv_ctrl,
			       struct ldb_server_sort_control *sort_ctrl)
{
	/* free the old details which are no longer going to be reachable. */
	if (store->vlv_details != NULL){
		TALLOC_FREE(store->vlv_details);
	}

	if (store->sort_details != NULL){
		TALLOC_FREE(store->sort_details);
	}

	store->vlv_details = talloc(store, struct ldb_vlv_req_control);
	if (store->vlv_details == NULL) {
		return LDB_ERR_OPERATIONS_ERROR;
	}
	*store->vlv_details = *vlv_ctrl;
	store->vlv_details->contextId = talloc_memdup(store, vlv_ctrl->contextId,
						      vlv_ctrl->ctxid_len);
	if (store->vlv_details->contextId == NULL) {
		return LDB_ERR_OPERATIONS_ERROR;
	}

	if (vlv_ctrl->type == 1) {
		char *v = talloc_array(store, char,
				       vlv_ctrl->match.gtOrEq.value_len + 1);

		if (v == NULL) {
			return LDB_ERR_OPERATIONS_ERROR;
		}

		memcpy(v, vlv_ctrl->match.gtOrEq.value, vlv_ctrl->match.gtOrEq.value_len);
		v[vlv_ctrl->match.gtOrEq.value_len] = '\0';

		store->vlv_details->match.gtOrEq.value = v;
	}

	store->sort_details = talloc(store, struct ldb_server_sort_control);
	if (store->sort_details == NULL) {
		return LDB_ERR_OPERATIONS_ERROR;
	}
	store->sort_details->attributeName = talloc_strdup(store,
							   sort_ctrl->attributeName);
	if (store->sort_details->attributeName == NULL) {
		return LDB_ERR_OPERATIONS_ERROR;
	}

	if (sort_ctrl->orderingRule == NULL) {
		store->sort_details->orderingRule = NULL;
	} else {
		store->sort_details->orderingRule = talloc_strdup(store,
								  sort_ctrl->orderingRule);
		if (store->sort_details->orderingRule == NULL) {
			return LDB_ERR_OPERATIONS_ERROR;
		}
	}
	store->sort_details->reverse = sort_ctrl->reverse;

	return LDB_SUCCESS;
}


static struct ldb_control **
vlv_copy_down_controls(TALLOC_CTX *mem_ctx, struct ldb_control **controls)
{

	struct ldb_control **new_controls;
	unsigned int i, j, num_ctrls;
	if (controls == NULL) {
		return NULL;
	}

	for (num_ctrls = 0; controls[num_ctrls]; num_ctrls++);

	new_controls = talloc_array(mem_ctx, struct ldb_control *, num_ctrls);
	if (new_controls == NULL) {
		return NULL;
	}

	for (j = 0, i = 0; i < (num_ctrls); i++) {
		struct ldb_control *control = controls[i];
		if (control->oid == NULL) {
			break;
		}
		/*
		 * Do not re-use VLV, nor the server-sort, both are
		 * already handled here.
		 */
		if (strcmp(control->oid, LDB_CONTROL_VLV_REQ_OID) == 0 ||
		    strcmp(control->oid, LDB_CONTROL_SERVER_SORT_OID) == 0) {
			continue;
		}
		/*
		 * ASQ changes everything, do not copy it down for the
		 * per-GUID search
		 */
		if (strcmp(control->oid, LDB_CONTROL_ASQ_OID) == 0) {
			continue;
		}
		new_controls[j] = talloc_steal(new_controls, control);
		/*
		 * Sadly the caller is not obliged to make this a
		 * proper talloc tree, so we do so here.
		 */
		if (control->data) {
			talloc_steal(control, control->data);
		}
		j++;
	}
	new_controls[j] = NULL;
	return new_controls;
}

static int vlv_search(struct ldb_module *module, struct ldb_request *req)
{
	struct ldb_context *ldb;
	struct ldb_control *control;
	struct ldb_control *sort_control;
	struct private_data *priv;
	struct ldb_vlv_req_control *vlv_ctrl;
	struct ldb_server_sort_control **sort_ctrl;
	struct ldb_request *search_req;
	struct vlv_context *ac;
	int ret, i, critical;

	ldb = ldb_module_get_ctx(module);

	control = ldb_request_get_control(req, LDB_CONTROL_VLV_REQ_OID);
	if (control == NULL) {
		/* There is no VLV. go on */
		return ldb_next_request(module, req);
	}
	critical = control->critical;
	control->critical = 0;

	sort_control = ldb_request_get_control(req, LDB_CONTROL_SERVER_SORT_OID);
	if (sort_control == NULL) {
		/* VLV needs sort */
		return LDB_ERR_OPERATIONS_ERROR;
	}

	vlv_ctrl = talloc_get_type(control->data, struct ldb_vlv_req_control);
	if (vlv_ctrl == NULL) {
		return LDB_ERR_OPERATIONS_ERROR;
	}

	sort_ctrl = talloc_get_type(sort_control->data, struct ldb_server_sort_control *);
	if (sort_ctrl == NULL) {
		return LDB_ERR_OPERATIONS_ERROR;
	}

	priv = talloc_get_type(ldb_module_get_private(module),
			       struct private_data);

	ac = talloc_zero(req, struct vlv_context);
	if (ac == NULL) {
		ldb_set_errstring(ldb, "Out of Memory");
		return LDB_ERR_OPERATIONS_ERROR;
	}

	ac->module = module;
	ac->req = req;
	ac->priv = priv;
	/* If there is no cookie, this is a new request, and we need to do the
	 * search in the database. Otherwise we try to refer to a previously
	 * saved search.
	 */
	if (vlv_ctrl->ctxid_len == 0) {
		static const char * const attrs[2] = {
			"objectGUID", NULL
		};

		ac->store = new_store(priv);
		if (ac->store == NULL) {
			return LDB_ERR_OPERATIONS_ERROR;
		}

		ret = copy_search_details(ac->store, vlv_ctrl, sort_ctrl[0]);
		if (ret != LDB_SUCCESS) {
			return ret;
		}

		ret = ldb_build_search_req_ex(&search_req, ldb, ac,
					      req->op.search.base,
					      req->op.search.scope,
					      req->op.search.tree,
					      attrs,
					      req->controls,
					      ac,
					      vlv_search_callback,
					      req);
		if (ret != LDB_SUCCESS) {
			return ret;
		}
		/* save it locally and remove it from the list */
		/* we do not need to replace them later as we
		 * are keeping the original req intact */
		if (!ldb_save_controls(control, search_req, NULL)) {
			return LDB_ERR_OPERATIONS_ERROR;
		}

		ac->store->down_controls = vlv_copy_down_controls(ac->store,
								  req->controls);

		if (ac->store->down_controls == NULL) {
			return LDB_ERR_OPERATIONS_ERROR;
		}

		return ldb_next_request(module, search_req);

	} else {
		struct results_store *current = NULL;
		uint8_t *id = vlv_ctrl->contextId;

		if (vlv_ctrl->ctxid_len != sizeof(uint32_t)){
			return LDB_ERR_UNWILLING_TO_PERFORM;
		}

		for (i = 0; i < priv->n_stores; i++) {
			current = priv->store[i];
			if (current == NULL) {
				continue;
			}
			if (memcmp(&current->contextId, id, sizeof(uint32_t)) == 0) {
				current->timestamp = time(NULL);
				break;
			}
		}
		if (i == priv->n_stores) {
			/* We were given a context id that we don't know about. */
			if (critical) {
				return LDAP_UNAVAILABLE_CRITICAL_EXTENSION;
			} else {
				return ldb_next_request(module, req);
			}
		}

		ac->store = current;
		ret = copy_search_details(ac->store, vlv_ctrl, sort_ctrl[0]);
		if (ret != LDB_SUCCESS) {
			return ret;
		}

		ret = vlv_results(ac, NULL);
		if (ret != LDB_SUCCESS) {
			/*
			 * vlv_results() will have called ldb_module_done
			 * if there was an error.
			 */
			return ret;
		}
		return ldb_module_done(req, ac->controls, NULL,
				       LDB_SUCCESS);
	}
}


static int vlv_request_init(struct ldb_module *module)
{
	struct ldb_context *ldb;
	struct private_data *data;
	int ret;

	ldb = ldb_module_get_ctx(module);

	data = talloc(module, struct private_data);
	if (data == NULL) {
		return LDB_ERR_OTHER;
	}

	data->next_free_id = 1;
	data->n_stores = VLV_N_SEARCHES;
	data->store = talloc_zero_array(data, struct results_store *, data->n_stores);

	ldb_module_set_private(module, data);

	ret = ldb_mod_register_control(module, LDB_CONTROL_VLV_REQ_OID);
	if (ret != LDB_SUCCESS) {
		ldb_debug(ldb, LDB_DEBUG_WARNING,
			  "vlv:"
			  "Unable to register control with rootdse!");
	}

	return ldb_next_init(module);
}

static const struct ldb_module_ops ldb_vlv_module_ops = {
	.name           = "vlv",
	.search         = vlv_search,
	.init_context 	= vlv_request_init
};

int ldb_vlv_init(const char *version)
{
	LDB_MODULE_CHECK_VERSION(version);
	return ldb_register_module(&ldb_vlv_module_ops);
}