summaryrefslogtreecommitdiff
path: root/source4/dsdb/schema/schema_set.c
blob: ce8facbef3c9e62f0ad027cf9d435cff44b30098 (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
/*
   Unix SMB/CIFS implementation.
   DSDB schema header

   Copyright (C) Stefan Metzmacher <metze@samba.org> 2006-2007
   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2006-2008
   Copyright (C) Matthieu Patou <mat@matws.net> 2011

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

   This program 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 General Public License for more details.

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

*/

#include "includes.h"
#include "lib/util/dlinklist.h"
#include "dsdb/samdb/samdb.h"
#include <ldb_module.h>
#include "param/param.h"
#include "librpc/ndr/libndr.h"
#include "librpc/gen_ndr/ndr_misc.h"
#include "lib/util/tsort.h"

/* change this when we change something in our schema code that
 * requires a re-index of the database
 */
#define SAMDB_INDEXING_VERSION "2"

/*
  override the name to attribute handler function
 */
const struct ldb_schema_attribute *dsdb_attribute_handler_override(struct ldb_context *ldb,
								   void *private_data,
								   const char *name)
{
	struct dsdb_schema *schema = talloc_get_type_abort(private_data, struct dsdb_schema);
	const struct dsdb_attribute *a = dsdb_attribute_by_lDAPDisplayName(schema, name);
	if (a == NULL) {
		/* this will fall back to ldb internal handling */
		return NULL;
	}
	return a->ldb_schema_attribute;
}
/*
 * Set the attribute handlers onto the LDB, and potentially write the
 * @INDEXLIST, @IDXONE and @ATTRIBUTES records.  The @ATTRIBUTES records
 * are required so we can operate on a schema-less database (say the
 * backend during emergency fixes) and during the schema load.
 */
static int dsdb_schema_set_indices_and_attributes(struct ldb_context *ldb, struct dsdb_schema *schema, bool write_indices_and_attributes)
{
	int ret = LDB_SUCCESS;
	struct ldb_result *res;
	struct ldb_result *res_idx;
	struct dsdb_attribute *attr;
	struct ldb_message *mod_msg;
	TALLOC_CTX *mem_ctx;
	struct ldb_message *msg;
	struct ldb_message *msg_idx;

	/* setup our own attribute name to schema handler */
	ldb_schema_attribute_set_override_handler(ldb, dsdb_attribute_handler_override, schema);

	if (!write_indices_and_attributes) {
		return ret;
	}

	mem_ctx = talloc_new(ldb);
	if (!mem_ctx) {
		return ldb_oom(ldb);
	}

	msg = ldb_msg_new(mem_ctx);
	if (!msg) {
		ldb_oom(ldb);
		goto op_error;
	}
	msg_idx = ldb_msg_new(mem_ctx);
	if (!msg_idx) {
		ldb_oom(ldb);
		goto op_error;
	}
	msg->dn = ldb_dn_new(msg, ldb, "@ATTRIBUTES");
	if (!msg->dn) {
		ldb_oom(ldb);
		goto op_error;
	}
	msg_idx->dn = ldb_dn_new(msg_idx, ldb, "@INDEXLIST");
	if (!msg_idx->dn) {
		ldb_oom(ldb);
		goto op_error;
	}

	ret = ldb_msg_add_string(msg_idx, "@IDXONE", "1");
	if (ret != LDB_SUCCESS) {
		goto op_error;
	}


	ret = ldb_msg_add_string(msg_idx, "@IDXVERSION", SAMDB_INDEXING_VERSION);
	if (ret != LDB_SUCCESS) {
		goto op_error;
	}

	for (attr = schema->attributes; attr; attr = attr->next) {
		const char *syntax = attr->syntax->ldb_syntax;

		if (!syntax) {
			syntax = attr->syntax->ldap_oid;
		}

		/*
		 * Write out a rough approximation of the schema
		 * as an @ATTRIBUTES value, for bootstrapping
		 */
		if (strcmp(syntax, LDB_SYNTAX_INTEGER) == 0) {
			ret = ldb_msg_add_string(msg, attr->lDAPDisplayName, "INTEGER");
		} else if (strcmp(syntax, LDB_SYNTAX_DIRECTORY_STRING) == 0) {
			ret = ldb_msg_add_string(msg, attr->lDAPDisplayName, "CASE_INSENSITIVE");
		}
		if (ret != LDB_SUCCESS) {
			break;
		}

		if (attr->searchFlags & SEARCH_FLAG_ATTINDEX) {
			ret = ldb_msg_add_string(msg_idx, "@IDXATTR", attr->lDAPDisplayName);
			if (ret != LDB_SUCCESS) {
				break;
			}
		}
	}

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

	/*
	 * Try to avoid churning the attributes too much,
	 * we only want to do this if they have changed
	 */
	ret = ldb_search(ldb, mem_ctx, &res, msg->dn, LDB_SCOPE_BASE, NULL,
			 NULL);
	if (ret == LDB_ERR_NO_SUCH_OBJECT) {
		ret = ldb_add(ldb, msg);
	} else if (ret != LDB_SUCCESS) {
	} else if (res->count != 1) {
		ret = ldb_add(ldb, msg);
	} else {
		ret = LDB_SUCCESS;
		/* Annoyingly added to our search results */
		ldb_msg_remove_attr(res->msgs[0], "distinguishedName");

		ret = ldb_msg_difference(ldb, mem_ctx,
		                         res->msgs[0], msg, &mod_msg);
		if (ret != LDB_SUCCESS) {
			goto op_error;
		}
		if (mod_msg->num_elements > 0) {
			ret = dsdb_replace(ldb, mod_msg, 0);
		}
		talloc_free(mod_msg);
	}

	if (ret == LDB_ERR_OPERATIONS_ERROR || ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS || ret == LDB_ERR_INVALID_DN_SYNTAX) {
		/* We might be on a read-only DB or LDAP */
		ret = LDB_SUCCESS;
	}
	if (ret != LDB_SUCCESS) {
		talloc_free(mem_ctx);
		return ret;
	}

	/* Now write out the indexes, as found in the schema (if they have changed) */

	ret = ldb_search(ldb, mem_ctx, &res_idx, msg_idx->dn, LDB_SCOPE_BASE,
			 NULL, NULL);
	if (ret == LDB_ERR_NO_SUCH_OBJECT) {
		ret = ldb_add(ldb, msg_idx);
	} else if (ret != LDB_SUCCESS) {
	} else if (res_idx->count != 1) {
		ret = ldb_add(ldb, msg_idx);
	} else {
		ret = LDB_SUCCESS;
		/* Annoyingly added to our search results */
		ldb_msg_remove_attr(res_idx->msgs[0], "distinguishedName");

		ret = ldb_msg_difference(ldb, mem_ctx,
		                         res_idx->msgs[0], msg_idx, &mod_msg);
		if (ret != LDB_SUCCESS) {
			goto op_error;
		}
		if (mod_msg->num_elements > 0) {
			ret = dsdb_replace(ldb, mod_msg, 0);
		}
		talloc_free(mod_msg);
	}
	if (ret == LDB_ERR_OPERATIONS_ERROR || ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS || ret == LDB_ERR_INVALID_DN_SYNTAX) {
		/* We might be on a read-only DB */
		ret = LDB_SUCCESS;
	}
	talloc_free(mem_ctx);
	return ret;

op_error:
	talloc_free(mem_ctx);
	return ldb_operr(ldb);
}


/*
  create extra attribute shortcuts
 */
static void dsdb_setup_attribute_shortcuts(struct ldb_context *ldb, struct dsdb_schema *schema)
{
	struct dsdb_attribute *attribute;

	/* setup fast access to one_way_link and DN format */
	for (attribute=schema->attributes; attribute; attribute=attribute->next) {
		attribute->dn_format = dsdb_dn_oid_to_format(attribute->syntax->ldap_oid);

		if (attribute->dn_format == DSDB_INVALID_DN) {
			attribute->one_way_link = false;
			continue;
		}

		/* these are not considered to be one way links for
		   the purpose of DN link fixups */
		if (ldb_attr_cmp("distinguishedName", attribute->lDAPDisplayName) == 0 ||
		    ldb_attr_cmp("objectCategory", attribute->lDAPDisplayName) == 0) {
			attribute->one_way_link = false;
			continue;
		}

		if (attribute->linkID == 0) {
			attribute->one_way_link = true;
			continue;
		}
		/* handle attributes with a linkID but no backlink */
		if ((attribute->linkID & 1) == 0 &&
		    dsdb_attribute_by_linkID(schema, attribute->linkID + 1) == NULL) {
			attribute->one_way_link = true;
			continue;
		}
		attribute->one_way_link = false;
	}
}

static int uint32_cmp(uint32_t c1, uint32_t c2)
{
	if (c1 == c2) return 0;
	return c1 > c2 ? 1 : -1;
}

static int dsdb_compare_class_by_lDAPDisplayName(struct dsdb_class **c1, struct dsdb_class **c2)
{
	return strcasecmp((*c1)->lDAPDisplayName, (*c2)->lDAPDisplayName);
}
static int dsdb_compare_class_by_governsID_id(struct dsdb_class **c1, struct dsdb_class **c2)
{
	return uint32_cmp((*c1)->governsID_id, (*c2)->governsID_id);
}
static int dsdb_compare_class_by_governsID_oid(struct dsdb_class **c1, struct dsdb_class **c2)
{
	return strcasecmp((*c1)->governsID_oid, (*c2)->governsID_oid);
}
static int dsdb_compare_class_by_cn(struct dsdb_class **c1, struct dsdb_class **c2)
{
	return strcasecmp((*c1)->cn, (*c2)->cn);
}

static int dsdb_compare_attribute_by_lDAPDisplayName(struct dsdb_attribute **a1, struct dsdb_attribute **a2)
{
	return strcasecmp((*a1)->lDAPDisplayName, (*a2)->lDAPDisplayName);
}
static int dsdb_compare_attribute_by_attributeID_id(struct dsdb_attribute **a1, struct dsdb_attribute **a2)
{
	return uint32_cmp((*a1)->attributeID_id, (*a2)->attributeID_id);
}
static int dsdb_compare_attribute_by_msDS_IntId(struct dsdb_attribute **a1, struct dsdb_attribute **a2)
{
	return uint32_cmp((*a1)->msDS_IntId, (*a2)->msDS_IntId);
}
static int dsdb_compare_attribute_by_attributeID_oid(struct dsdb_attribute **a1, struct dsdb_attribute **a2)
{
	return strcasecmp((*a1)->attributeID_oid, (*a2)->attributeID_oid);
}
static int dsdb_compare_attribute_by_linkID(struct dsdb_attribute **a1, struct dsdb_attribute **a2)
{
	return uint32_cmp((*a1)->linkID, (*a2)->linkID);
}

/**
 * Clean up Classes and Attributes accessor arrays
 */
static void dsdb_sorted_accessors_free(struct dsdb_schema *schema)
{
	/* free classes accessors */
	TALLOC_FREE(schema->classes_by_lDAPDisplayName);
	TALLOC_FREE(schema->classes_by_governsID_id);
	TALLOC_FREE(schema->classes_by_governsID_oid);
	TALLOC_FREE(schema->classes_by_cn);
	/* free attribute accessors */
	TALLOC_FREE(schema->attributes_by_lDAPDisplayName);
	TALLOC_FREE(schema->attributes_by_attributeID_id);
	TALLOC_FREE(schema->attributes_by_msDS_IntId);
	TALLOC_FREE(schema->attributes_by_attributeID_oid);
	TALLOC_FREE(schema->attributes_by_linkID);
}

/*
  create the sorted accessor arrays for the schema
 */
int dsdb_setup_sorted_accessors(struct ldb_context *ldb,
				struct dsdb_schema *schema)
{
	struct dsdb_class *cur;
	struct dsdb_attribute *a;
	unsigned int i;
	unsigned int num_int_id;
	int ret;

	for (i=0; i < schema->classes_to_remove_size; i++) {
		DLIST_REMOVE(schema->classes, schema->classes_to_remove[i]);
		TALLOC_FREE(schema->classes_to_remove[i]);
	}
	for (i=0; i < schema->attributes_to_remove_size; i++) {
		DLIST_REMOVE(schema->attributes, schema->attributes_to_remove[i]);
		TALLOC_FREE(schema->attributes_to_remove[i]);
	}

	TALLOC_FREE(schema->classes_to_remove);
	schema->classes_to_remove_size = 0;
	TALLOC_FREE(schema->attributes_to_remove);
	schema->attributes_to_remove_size = 0;

	/* free all caches */
	dsdb_sorted_accessors_free(schema);

	/* count the classes */
	for (i=0, cur=schema->classes; cur; i++, cur=cur->next) /* noop */ ;
	schema->num_classes = i;

	/* setup classes_by_* */
	schema->classes_by_lDAPDisplayName = talloc_array(schema, struct dsdb_class *, i);
	schema->classes_by_governsID_id    = talloc_array(schema, struct dsdb_class *, i);
	schema->classes_by_governsID_oid   = talloc_array(schema, struct dsdb_class *, i);
	schema->classes_by_cn              = talloc_array(schema, struct dsdb_class *, i);
	if (schema->classes_by_lDAPDisplayName == NULL ||
	    schema->classes_by_governsID_id == NULL ||
	    schema->classes_by_governsID_oid == NULL ||
	    schema->classes_by_cn == NULL) {
		goto failed;
	}

	for (i=0, cur=schema->classes; cur; i++, cur=cur->next) {
		schema->classes_by_lDAPDisplayName[i] = cur;
		schema->classes_by_governsID_id[i]    = cur;
		schema->classes_by_governsID_oid[i]   = cur;
		schema->classes_by_cn[i]              = cur;
	}

	/* sort the arrays */
	TYPESAFE_QSORT(schema->classes_by_lDAPDisplayName, schema->num_classes, dsdb_compare_class_by_lDAPDisplayName);
	TYPESAFE_QSORT(schema->classes_by_governsID_id, schema->num_classes, dsdb_compare_class_by_governsID_id);
	TYPESAFE_QSORT(schema->classes_by_governsID_oid, schema->num_classes, dsdb_compare_class_by_governsID_oid);
	TYPESAFE_QSORT(schema->classes_by_cn, schema->num_classes, dsdb_compare_class_by_cn);

	/* now build the attribute accessor arrays */

	/* count the attributes
	 * and attributes with msDS-IntId set */
	num_int_id = 0;
	for (i=0, a=schema->attributes; a; i++, a=a->next) {
		if (a->msDS_IntId != 0) {
			num_int_id++;
		}
	}
	schema->num_attributes = i;
	schema->num_int_id_attr = num_int_id;

	/* setup attributes_by_* */
	schema->attributes_by_lDAPDisplayName = talloc_array(schema, struct dsdb_attribute *, i);
	schema->attributes_by_attributeID_id    = talloc_array(schema, struct dsdb_attribute *, i);
	schema->attributes_by_msDS_IntId        = talloc_array(schema,
	                                                       struct dsdb_attribute *, num_int_id);
	schema->attributes_by_attributeID_oid   = talloc_array(schema, struct dsdb_attribute *, i);
	schema->attributes_by_linkID              = talloc_array(schema, struct dsdb_attribute *, i);
	if (schema->attributes_by_lDAPDisplayName == NULL ||
	    schema->attributes_by_attributeID_id == NULL ||
	    schema->attributes_by_msDS_IntId == NULL ||
	    schema->attributes_by_attributeID_oid == NULL ||
	    schema->attributes_by_linkID == NULL) {
		goto failed;
	}

	num_int_id = 0;
	for (i=0, a=schema->attributes; a; i++, a=a->next) {
		schema->attributes_by_lDAPDisplayName[i] = a;
		schema->attributes_by_attributeID_id[i]    = a;
		schema->attributes_by_attributeID_oid[i]   = a;
		schema->attributes_by_linkID[i]          = a;
		/* append attr-by-msDS-IntId values */
		if (a->msDS_IntId != 0) {
			schema->attributes_by_msDS_IntId[num_int_id] = a;
			num_int_id++;
		}
	}
	SMB_ASSERT(num_int_id == schema->num_int_id_attr);

	/* sort the arrays */
	TYPESAFE_QSORT(schema->attributes_by_lDAPDisplayName, schema->num_attributes, dsdb_compare_attribute_by_lDAPDisplayName);
	TYPESAFE_QSORT(schema->attributes_by_attributeID_id, schema->num_attributes, dsdb_compare_attribute_by_attributeID_id);
	TYPESAFE_QSORT(schema->attributes_by_msDS_IntId, schema->num_int_id_attr, dsdb_compare_attribute_by_msDS_IntId);
	TYPESAFE_QSORT(schema->attributes_by_attributeID_oid, schema->num_attributes, dsdb_compare_attribute_by_attributeID_oid);
	TYPESAFE_QSORT(schema->attributes_by_linkID, schema->num_attributes, dsdb_compare_attribute_by_linkID);

	dsdb_setup_attribute_shortcuts(ldb, schema);

	ret = schema_fill_constructed(schema);
	if (ret != LDB_SUCCESS) {
		dsdb_sorted_accessors_free(schema);
		return ret;
	}

	return LDB_SUCCESS;

failed:
	dsdb_sorted_accessors_free(schema);
	return ldb_oom(ldb);
}

/**
 * Attach the schema to an opaque pointer on the ldb,
 * so ldb modules can find it
 */
int dsdb_set_schema(struct ldb_context *ldb, struct dsdb_schema *schema)
{
	struct dsdb_schema *old_schema;
	int ret;

	ret = dsdb_setup_sorted_accessors(ldb, schema);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	old_schema = ldb_get_opaque(ldb, "dsdb_schema");

	ret = ldb_set_opaque(ldb, "dsdb_schema", schema);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	/* Remove the reference to the schema we just overwrote - if there was
	 * none, NULL is harmless here */
	if (old_schema != schema) {
		talloc_unlink(ldb, old_schema);
		talloc_steal(ldb, schema);
	}

	ret = ldb_set_opaque(ldb, "dsdb_use_global_schema", NULL);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	/* Set the new attributes based on the new schema */
	ret = dsdb_schema_set_indices_and_attributes(ldb, schema, true);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	return LDB_SUCCESS;
}

/**
 * Global variable to hold one copy of the schema, used to avoid memory bloat
 */
static struct dsdb_schema *global_schema;

/**
 * Make this ldb use a specified schema, already fully calculated and belonging to another ldb
 *
 * The write_indices_and_attributes controls writing of the @ records
 * because we cannot write to a database that does not yet exist on
 * disk.
 */
int dsdb_reference_schema(struct ldb_context *ldb, struct dsdb_schema *schema,
			  bool write_indices_and_attributes)
{
	int ret;
	struct dsdb_schema *old_schema;
	old_schema = ldb_get_opaque(ldb, "dsdb_schema");
	ret = ldb_set_opaque(ldb, "dsdb_schema", schema);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	/* Remove the reference to the schema we just overwrote - if there was
	 * none, NULL is harmless here */
	talloc_unlink(ldb, old_schema);

	if (talloc_reference(ldb, schema) == NULL) {
		return ldb_oom(ldb);
	}

	/* Make this ldb use local schema preferably */
	ret = ldb_set_opaque(ldb, "dsdb_use_global_schema", NULL);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	ret = dsdb_schema_set_indices_and_attributes(ldb, schema, write_indices_and_attributes);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	return LDB_SUCCESS;
}

/**
 * Make this ldb use the 'global' schema, setup to avoid having multiple copies in this process
 */
int dsdb_set_global_schema(struct ldb_context *ldb)
{
	int ret;
	void *use_global_schema = (void *)1;
	if (!global_schema) {
		return LDB_SUCCESS;
	}
	ret = ldb_set_opaque(ldb, "dsdb_use_global_schema", use_global_schema);
	if (ret != LDB_SUCCESS) {
		return ret;
	}

	/* Set the new attributes based on the new schema */
	ret = dsdb_schema_set_indices_and_attributes(ldb, global_schema, false /* Don't write indices and attributes, it's expensive */);
	if (ret == LDB_SUCCESS) {
		/* Keep a reference to this schema, just in case the original copy is replaced */
		if (talloc_reference(ldb, global_schema) == NULL) {
			return ldb_oom(ldb);
		}
	}

	return ret;
}

bool dsdb_uses_global_schema(struct ldb_context *ldb)
{
	return (ldb_get_opaque(ldb, "dsdb_use_global_schema") != NULL);
}

/**
 * Find the schema object for this ldb
 *
 * If reference_ctx is not NULL, then talloc_reference onto that context
 */

struct dsdb_schema *dsdb_get_schema(struct ldb_context *ldb, TALLOC_CTX *reference_ctx)
{
	const void *p;
	struct dsdb_schema *schema_out;
	struct dsdb_schema *schema_in;
	bool use_global_schema;
	TALLOC_CTX *tmp_ctx = talloc_new(reference_ctx);
	if (!tmp_ctx) {
		return NULL;
	}

	/* see if we have a cached copy */
	use_global_schema = dsdb_uses_global_schema(ldb);
	if (use_global_schema) {
		schema_in = global_schema;
	} else {
		p = ldb_get_opaque(ldb, "dsdb_schema");

		schema_in = talloc_get_type(p, struct dsdb_schema);
		if (!schema_in) {
			talloc_free(tmp_ctx);
			return NULL;
		}
	}

	if (schema_in->refresh_fn && !schema_in->refresh_in_progress) {
		if (!talloc_reference(tmp_ctx, schema_in)) {
			/*
			 * ensure that the schema_in->refresh_in_progress
			 * remains valid for the right amount of time
			 */
			talloc_free(tmp_ctx);
			return NULL;
		}
		schema_in->refresh_in_progress = true;
		/* This may change schema, if it needs to reload it from disk */
		schema_out = schema_in->refresh_fn(schema_in->loaded_from_module,
						   schema_in,
						   use_global_schema);
		schema_in->refresh_in_progress = false;
	} else {
		schema_out = schema_in;
	}

	/* This removes the extra reference above */
	talloc_free(tmp_ctx);
	if (!reference_ctx) {
		return schema_out;
	} else {
		return talloc_reference(reference_ctx, schema_out);
	}
}

/**
 * Make the schema found on this ldb the 'global' schema
 */

void dsdb_make_schema_global(struct ldb_context *ldb, struct dsdb_schema *schema)
{
	if (!schema) {
		return;
	}

	if (global_schema) {
		talloc_unlink(talloc_autofree_context(), global_schema);
	}

	/* we want the schema to be around permanently */
	talloc_reparent(ldb, talloc_autofree_context(), schema);
	global_schema = schema;

	/* This calls the talloc_reference() of the global schema back onto the ldb */
	dsdb_set_global_schema(ldb);
}

/**
 * When loading the schema from LDIF files, we don't get the extended DNs.
 *
 * We need to set these up, so that from the moment we start the provision,
 * the defaultObjectCategory links are set up correctly.
 */
int dsdb_schema_fill_extended_dn(struct ldb_context *ldb, struct dsdb_schema *schema)
{
	struct dsdb_class *cur;
	const struct dsdb_class *target_class;
	for (cur = schema->classes; cur; cur = cur->next) {
		const struct ldb_val *rdn;
		struct ldb_val guid;
		NTSTATUS status;
		struct ldb_dn *dn = ldb_dn_new(NULL, ldb, cur->defaultObjectCategory);

		if (!dn) {
			return LDB_ERR_INVALID_DN_SYNTAX;
		}
		rdn = ldb_dn_get_component_val(dn, 0);
		if (!rdn) {
			talloc_free(dn);
			return LDB_ERR_INVALID_DN_SYNTAX;
		}
		target_class = dsdb_class_by_cn_ldb_val(schema, rdn);
		if (!target_class) {
			talloc_free(dn);
			return LDB_ERR_CONSTRAINT_VIOLATION;
		}

		status = GUID_to_ndr_blob(&target_class->objectGUID, dn, &guid);
		if (!NT_STATUS_IS_OK(status)) {
			talloc_free(dn);
			return ldb_operr(ldb);
		}
		ldb_dn_set_extended_component(dn, "GUID", &guid);

		cur->defaultObjectCategory = ldb_dn_get_extended_linearized(cur, dn, 1);
		talloc_free(dn);
	}
	return LDB_SUCCESS;
}

/**
 * @brief Add a new element to the schema and checks if it's a duplicate
 *
 * This function will add a new element to the schema and checks for existing
 * duplicates.
 *
 * @param[in]  ldb                A pointer to an LDB context
 *
 * @param[in]  schema             A pointer to the dsdb_schema where the element
 *                                will be added.
 *
 * @param[in]  msg                The ldb_message object representing the element
 *                                to add.
 *
 * @param[in]  checkdups          A boolean to indicate if checks for duplicates
 *                                should be done.
 *
 * @return                        A WERROR code
 */
WERROR dsdb_schema_set_el_from_ldb_msg_dups(struct ldb_context *ldb, struct dsdb_schema *schema,
					    struct ldb_message *msg, bool checkdups)
{
	const char* tstring;
	time_t ts;
	tstring = ldb_msg_find_attr_as_string(msg, "whenChanged", NULL);
	/* keep a trace of the ts of the most recently changed object */
	if (tstring) {
		ts = ldb_string_to_time(tstring);
		if (ts > schema->ts_last_change) {
			schema->ts_last_change = ts;
		}
	}
	if (samdb_find_attribute(ldb, msg,
				 "objectclass", "attributeSchema") != NULL) {

		return dsdb_set_attribute_from_ldb_dups(ldb, schema, msg, checkdups);
	} else if (samdb_find_attribute(ldb, msg,
				 "objectclass", "classSchema") != NULL) {
		return dsdb_set_class_from_ldb_dups(schema, msg, checkdups);
	}
	/* Don't fail on things not classes or attributes */
	return WERR_OK;
}

WERROR dsdb_schema_set_el_from_ldb_msg(struct ldb_context *ldb,
				       struct dsdb_schema *schema,
				       struct ldb_message *msg)
{
	return dsdb_schema_set_el_from_ldb_msg_dups(ldb, schema, msg, false);
}

/**
 * Rather than read a schema from the LDB itself, read it from an ldif
 * file.  This allows schema to be loaded and used while adding the
 * schema itself to the directory.
 */

WERROR dsdb_set_schema_from_ldif(struct ldb_context *ldb,
				 const char *pf, const char *df,
				 const char *dn)
{
	struct ldb_ldif *ldif;
	struct ldb_message *msg;
	TALLOC_CTX *mem_ctx;
	WERROR status;
	int ret;
	struct dsdb_schema *schema;
	const struct ldb_val *prefix_val;
	const struct ldb_val *info_val;
	struct ldb_val info_val_default;


	mem_ctx = talloc_new(ldb);
	if (!mem_ctx) {
		goto nomem;
	}

	schema = dsdb_new_schema(mem_ctx);
	if (!schema) {
		goto nomem;
	}
	schema->base_dn = ldb_dn_new(schema, ldb, dn);
	if (!schema->base_dn) {
		goto nomem;
	}
	schema->fsmo.we_are_master = true;
	schema->fsmo.update_allowed = true;
	schema->fsmo.master_dn = ldb_dn_new(schema, ldb, "@PROVISION_SCHEMA_MASTER");
	if (!schema->fsmo.master_dn) {
		goto nomem;
	}

	/*
	 * load the prefixMap attribute from pf
	 */
	ldif = ldb_ldif_read_string(ldb, &pf);
	if (!ldif) {
		status = WERR_INVALID_PARAM;
		goto failed;
	}
	talloc_steal(mem_ctx, ldif);

	ret = ldb_msg_normalize(ldb, mem_ctx, ldif->msg, &msg);
	if (ret != LDB_SUCCESS) {
		goto nomem;
	}
	talloc_free(ldif);

	prefix_val = ldb_msg_find_ldb_val(msg, "prefixMap");
	if (!prefix_val) {
	    	status = WERR_INVALID_PARAM;
		goto failed;
	}

	info_val = ldb_msg_find_ldb_val(msg, "schemaInfo");
	if (!info_val) {
		status = dsdb_schema_info_blob_new(mem_ctx, &info_val_default);
		W_ERROR_NOT_OK_GOTO(status, failed);
		info_val = &info_val_default;
	}

	status = dsdb_load_oid_mappings_ldb(schema, prefix_val, info_val);
	if (!W_ERROR_IS_OK(status)) {
		DEBUG(0,("ERROR: dsdb_load_oid_mappings_ldb() failed with %s\n", win_errstr(status)));
		goto failed;
	}

	schema->ts_last_change = 0;
	/* load the attribute and class definitions out of df */
	while ((ldif = ldb_ldif_read_string(ldb, &df))) {
		talloc_steal(mem_ctx, ldif);

		ret = ldb_msg_normalize(ldb, ldif, ldif->msg, &msg);
		if (ret != LDB_SUCCESS) {
			goto nomem;
		}

		status = dsdb_schema_set_el_from_ldb_msg(ldb, schema, msg);
		talloc_free(ldif);
		if (!W_ERROR_IS_OK(status)) {
			goto failed;
		}
	}

	ret = dsdb_set_schema(ldb, schema);
	if (ret != LDB_SUCCESS) {
		status = WERR_FOOBAR;
		goto failed;
	}

	ret = dsdb_schema_fill_extended_dn(ldb, schema);
	if (ret != LDB_SUCCESS) {
		status = WERR_FOOBAR;
		goto failed;
	}

	goto done;

nomem:
	status = WERR_NOMEM;
failed:
done:
	talloc_free(mem_ctx);
	return status;
}