summaryrefslogtreecommitdiff
path: root/source3/smbd/blocking.c
blob: 0b24fc825718a2d02ac1255849184301936eb664 (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
/* 
   Unix SMB/CIFS implementation.
   Blocking Locking functions
   Copyright (C) Jeremy Allison 1998-2003
   
   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"
#undef DBGC_CLASS
#define DBGC_CLASS DBGC_LOCKING

extern int max_send;

/****************************************************************************
 This is the structure to queue to implement blocking locks.
 notify. It consists of the requesting SMB and the expiry time.
*****************************************************************************/

typedef struct _blocking_lock_record {
	struct _blocking_lock_record *next;
	struct _blocking_lock_record *prev;
	int com_type;
	files_struct *fsp;
	struct timeval expire_time;
	int lock_num;
	SMB_BIG_UINT offset;
	SMB_BIG_UINT count;
	uint32 lock_pid;
	uint32 blocking_pid; /* PID that blocks us. */
	enum brl_flavour lock_flav;
	enum brl_type lock_type;
	char *inbuf;
	int length;
} blocking_lock_record;

/* dlink list we store pending lock records on. */
static blocking_lock_record *blocking_lock_queue;

/* dlink list we move cancelled lock records onto. */
static blocking_lock_record *blocking_lock_cancelled_queue;

/* The event that makes us process our blocking lock queue */
static struct timed_event *brl_timeout;

/****************************************************************************
 Destructor for the above structure.
****************************************************************************/

static void free_blocking_lock_record(blocking_lock_record *blr)
{
	SAFE_FREE(blr->inbuf);
	SAFE_FREE(blr);
}

/****************************************************************************
 Determine if this is a secondary element of a chained SMB.
  **************************************************************************/

static BOOL in_chained_smb(void)
{
	return (chain_size != 0);
}

static void received_unlock_msg(struct messaging_context *msg,
				void *private_data,
				uint32_t msg_type,
				struct server_id server_id,
				DATA_BLOB *data);
static void process_blocking_lock_queue(void);

static void brl_timeout_fn(struct event_context *event_ctx,
			   struct timed_event *te,
			   const struct timeval *now,
			   void *private_data)
{
	SMB_ASSERT(brl_timeout == te);
	TALLOC_FREE(brl_timeout);

	change_to_root_user();	/* TODO: Possibly run all timed events as
				 * root */

	process_blocking_lock_queue();
}

/****************************************************************************
 After a change to blocking_lock_queue, recalculate the timed_event for the
 next processing.
****************************************************************************/

static BOOL recalc_brl_timeout(void)
{
	blocking_lock_record *brl;
	struct timeval next_timeout;

	TALLOC_FREE(brl_timeout);

	next_timeout = timeval_zero();	

	for (brl = blocking_lock_queue; brl; brl = brl->next) {
		if (timeval_is_zero(&brl->expire_time)) {
			/*
			 * If we're blocked on pid 0xFFFFFFFF this is
			 * a POSIX lock, so calculate a timeout of
			 * 10 seconds into the future.
			 */
                        if (brl->blocking_pid == 0xFFFFFFFF) {
				struct timeval psx_to = timeval_current_ofs(10, 0);
				next_timeout = timeval_min(&next_timeout, &psx_to);
                        }

			continue;
		}

		if (timeval_is_zero(&next_timeout)) {
			next_timeout = brl->expire_time;
		}
		else {
			next_timeout = timeval_min(&next_timeout,
						   &brl->expire_time);
		}
	}

	if (timeval_is_zero(&next_timeout)) {
		return True;
	}

	if (!(brl_timeout = event_add_timed(smbd_event_context(), NULL,
					    next_timeout, "brl_timeout",
					    brl_timeout_fn, NULL))) {
		return False;
	}

	return True;
}


/****************************************************************************
 Function to push a blocking lock request onto the lock queue.
****************************************************************************/

BOOL push_blocking_lock_request( struct byte_range_lock *br_lck,
		const char *inbuf, int length,
		files_struct *fsp,
		int lock_timeout,
		int lock_num,
		uint32 lock_pid,
		enum brl_type lock_type,
		enum brl_flavour lock_flav,
		SMB_BIG_UINT offset,
		SMB_BIG_UINT count,
		uint32 blocking_pid)
{
	static BOOL set_lock_msg;
	blocking_lock_record *blr;
	NTSTATUS status;

	if(in_chained_smb() ) {
		DEBUG(0,("push_blocking_lock_request: cannot queue a chained request (currently).\n"));
		return False;
	}

	/*
	 * Now queue an entry on the blocking lock queue. We setup
	 * the expiration time here.
	 */

	if((blr = SMB_MALLOC_P(blocking_lock_record)) == NULL) {
		DEBUG(0,("push_blocking_lock_request: Malloc fail !\n" ));
		return False;
	}

	blr->next = NULL;
	blr->prev = NULL;

	if((blr->inbuf = (char *)SMB_MALLOC(length)) == NULL) {
		DEBUG(0,("push_blocking_lock_request: Malloc fail (2)!\n" ));
		SAFE_FREE(blr);
		return False;
	}

	blr->com_type = CVAL(inbuf,smb_com);
	blr->fsp = fsp;
	if (lock_timeout == -1) {
		blr->expire_time.tv_sec = 0;
		blr->expire_time.tv_usec = 0; /* Never expire. */
	} else {
		blr->expire_time = timeval_current_ofs(lock_timeout/1000,
					(lock_timeout % 1000) * 1000);
	}
	blr->lock_num = lock_num;
	blr->lock_pid = lock_pid;
	blr->blocking_pid = blocking_pid;
	blr->lock_flav = lock_flav;
	blr->lock_type = lock_type;
	blr->offset = offset;
	blr->count = count;
	memcpy(blr->inbuf, inbuf, length);
	blr->length = length;

	/* Add a pending lock record for this. */
	status = brl_lock(smbd_messaging_context(), br_lck,
			lock_pid,
			procid_self(),
			offset,
			count,
			lock_type == READ_LOCK ? PENDING_READ_LOCK : PENDING_WRITE_LOCK,
			blr->lock_flav,
			lock_timeout ? True : False, /* blocking_lock. */
			NULL);

	if (!NT_STATUS_IS_OK(status)) {
		DEBUG(0,("push_blocking_lock_request: failed to add PENDING_LOCK record.\n"));
		DLIST_REMOVE(blocking_lock_queue, blr);
		free_blocking_lock_record(blr);
		return False;
	}

	DLIST_ADD_END(blocking_lock_queue, blr, blocking_lock_record *);
	recalc_brl_timeout();

	/* Ensure we'll receive messages when this is unlocked. */
	if (!set_lock_msg) {
		messaging_register(smbd_messaging_context(), NULL,
				   MSG_SMB_UNLOCK, received_unlock_msg);
		set_lock_msg = True;
	}

	DEBUG(3,("push_blocking_lock_request: lock request length=%d blocked with "
		"expiry time (%u sec. %u usec) (+%d msec) for fnum = %d, name = %s\n",
		length, (unsigned int)blr->expire_time.tv_sec,
		(unsigned int)blr->expire_time.tv_usec, lock_timeout,
		blr->fsp->fnum, blr->fsp->fsp_name ));

	/* Push the MID of this packet on the signing queue. */
	srv_defer_sign_response(SVAL(inbuf,smb_mid));

	return True;
}

/****************************************************************************
 Return a smd with a given size.
*****************************************************************************/

static void send_blocking_reply(char *outbuf, int outsize, const char *inbuf)
{
	if(outsize > 4) {
		smb_setlen(inbuf, outbuf,outsize - 4);
	}

	if (!send_smb(smbd_server_fd(),outbuf)) {
		exit_server_cleanly("send_blocking_reply: send_smb failed.");
	}
}

/****************************************************************************
 Return a lockingX success SMB.
*****************************************************************************/

static void reply_lockingX_success(blocking_lock_record *blr)
{
	char *outbuf = get_OutBuffer();
	int bufsize = BUFFER_SIZE;
	char *inbuf = blr->inbuf;
	int outsize = 0;

	construct_reply_common(inbuf, outbuf);
	set_message(inbuf,outbuf,2,0,True);

	/*
	 * As this message is a lockingX call we must handle
	 * any following chained message correctly.
	 * This is normally handled in construct_reply(),
	 * but as that calls switch_message, we can't use
	 * that here and must set up the chain info manually.
	 */

	outsize = chain_reply(inbuf,&outbuf,blr->length,bufsize);

	outsize += chain_size;

	send_blocking_reply(outbuf,outsize,inbuf);
}

/****************************************************************************
 Return a generic lock fail error blocking call.
*****************************************************************************/

static void generic_blocking_lock_error(blocking_lock_record *blr, NTSTATUS status)
{
	char *outbuf = get_OutBuffer();
	char *inbuf = blr->inbuf;
	construct_reply_common(inbuf, outbuf);

	/* whenever a timeout is given w2k maps LOCK_NOT_GRANTED to
	   FILE_LOCK_CONFLICT! (tridge) */
	if (NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) {
		status = NT_STATUS_FILE_LOCK_CONFLICT;
	}

	if (NT_STATUS_EQUAL(status, NT_STATUS_FILE_LOCK_CONFLICT)) {
		/* Store the last lock error. */
		files_struct *fsp = blr->fsp;

		fsp->last_lock_failure.context.smbpid = blr->lock_pid;
		fsp->last_lock_failure.context.tid = fsp->conn->cnum;
		fsp->last_lock_failure.context.pid = procid_self();
		fsp->last_lock_failure.start = blr->offset;
		fsp->last_lock_failure.size = blr->count;
		fsp->last_lock_failure.fnum = fsp->fnum;
		fsp->last_lock_failure.lock_type = READ_LOCK; /* Don't care. */
		fsp->last_lock_failure.lock_flav = blr->lock_flav;
	}

	ERROR_NT(status);
	if (!send_smb(smbd_server_fd(),outbuf)) {
		exit_server_cleanly("generic_blocking_lock_error: send_smb failed.");
	}
}

/****************************************************************************
 Return a lock fail error for a lockingX call. Undo all the locks we have 
 obtained first.
*****************************************************************************/

static void reply_lockingX_error(blocking_lock_record *blr, NTSTATUS status)
{
	char *inbuf = blr->inbuf;
	files_struct *fsp = blr->fsp;
	uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
	SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT) 0;
	uint32 lock_pid;
	unsigned char locktype = CVAL(inbuf,smb_vwv3);
	BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
	char *data;
	int i;

	data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
	
	/* 
	 * Data now points at the beginning of the list
	 * of smb_lkrng structs.
	 */

	/*
	 * Ensure we don't do a remove on the lock that just failed,
	 * as under POSIX rules, if we have a lock already there, we
	 * will delete it (and we shouldn't) .....
	 */
	
	for(i = blr->lock_num - 1; i >= 0; i--) {
		BOOL err;
		
		lock_pid = get_lock_pid( data, i, large_file_format);
		count = get_lock_count( data, i, large_file_format);
		offset = get_lock_offset( data, i, large_file_format, &err);
		
		/*
		 * We know err cannot be set as if it was the lock
		 * request would never have been queued. JRA.
		 */
		
		do_unlock(smbd_messaging_context(),
			fsp,
			lock_pid,
			count,
			offset,
			WINDOWS_LOCK);
	}
	
	generic_blocking_lock_error(blr, status);
}

/****************************************************************************
 Return a lock fail error.
*****************************************************************************/

static void blocking_lock_reply_error(blocking_lock_record *blr, NTSTATUS status)
{
	switch(blr->com_type) {
	case SMBlockingX:
		reply_lockingX_error(blr, status);
		break;
	case SMBtrans2:
	case SMBtranss2:
		{
			char *outbuf = get_OutBuffer();
			char *inbuf = blr->inbuf;
			construct_reply_common(inbuf, outbuf);
			/* construct_reply_common has done us the favor to pre-fill the
			 * command field with SMBtranss2 which is wrong :-)
			 */
			SCVAL(outbuf,smb_com,SMBtrans2);
			ERROR_NT(status);
			if (!send_smb(smbd_server_fd(),outbuf)) {
				exit_server_cleanly("blocking_lock_reply_error: send_smb failed.");
			}
			break;
		}
	default:
		DEBUG(0,("blocking_lock_reply_error: PANIC - unknown type on blocking lock queue - exiting.!\n"));
		exit_server("PANIC - unknown type on blocking lock queue");
	}
}

/****************************************************************************
 Attempt to finish off getting all pending blocking locks for a lockingX call.
 Returns True if we want to be removed from the list.
*****************************************************************************/

static BOOL process_lockingX(blocking_lock_record *blr)
{
	char *inbuf = blr->inbuf;
	unsigned char locktype = CVAL(inbuf,smb_vwv3);
	files_struct *fsp = blr->fsp;
	uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
	uint16 num_locks = SVAL(inbuf,smb_vwv7);
	SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT)0;
	uint32 lock_pid;
	BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
	char *data;
	NTSTATUS status = NT_STATUS_OK;

	data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);

	/* 
	 * Data now points at the beginning of the list
	 * of smb_lkrng structs.
	 */

	for(; blr->lock_num < num_locks; blr->lock_num++) {
		struct byte_range_lock *br_lck = NULL;
		BOOL err;

		lock_pid = get_lock_pid( data, blr->lock_num, large_file_format);
		count = get_lock_count( data, blr->lock_num, large_file_format);
		offset = get_lock_offset( data, blr->lock_num, large_file_format, &err);
		
		/*
		 * We know err cannot be set as if it was the lock
		 * request would never have been queued. JRA.
		 */
		errno = 0;
		br_lck = do_lock(smbd_messaging_context(),
				fsp,
				lock_pid,
				count,
				offset, 
				((locktype & LOCKING_ANDX_SHARED_LOCK) ?
					READ_LOCK : WRITE_LOCK),
				WINDOWS_LOCK,
				True,
				&status,
				&blr->blocking_pid);

		TALLOC_FREE(br_lck);

		if (NT_STATUS_IS_ERR(status)) {
			break;
		}
	}

	if(blr->lock_num == num_locks) {
		/*
		 * Success - we got all the locks.
		 */
		
		DEBUG(3,("process_lockingX file = %s, fnum=%d type=%d num_locks=%d\n",
			 fsp->fsp_name, fsp->fnum, (unsigned int)locktype, num_locks) );

		reply_lockingX_success(blr);
		return True;
	} else if (!NT_STATUS_EQUAL(status,NT_STATUS_LOCK_NOT_GRANTED) &&
			!NT_STATUS_EQUAL(status,NT_STATUS_FILE_LOCK_CONFLICT)) {
			/*
			 * We have other than a "can't get lock"
			 * error. Free any locks we had and return an error.
			 * Return True so we get dequeued.
			 */
		
		blocking_lock_reply_error(blr, status);
		return True;
	}

	/*
	 * Still can't get all the locks - keep waiting.
	 */
	
	DEBUG(10,("process_lockingX: only got %d locks of %d needed for file %s, fnum = %d. \
Waiting....\n", 
		  blr->lock_num, num_locks, fsp->fsp_name, fsp->fnum));
	
	return False;
}

/****************************************************************************
 Attempt to get the posix lock request from a SMBtrans2 call.
 Returns True if we want to be removed from the list.
*****************************************************************************/

static BOOL process_trans2(blocking_lock_record *blr)
{
	struct smb_request *req;
	char params[2];
	NTSTATUS status;
	struct byte_range_lock *br_lck = do_lock(smbd_messaging_context(),
						blr->fsp,
						blr->lock_pid,
						blr->count,
						blr->offset,
						blr->lock_type,
						blr->lock_flav,
						True,
						&status,
						&blr->blocking_pid);
	TALLOC_FREE(br_lck);

	if (!NT_STATUS_IS_OK(status)) {
		if (ERROR_WAS_LOCK_DENIED(status)) {
			/* Still can't get the lock, just keep waiting. */
			return False;
		}	
		/*
		 * We have other than a "can't get lock"
		 * error. Send an error and return True so we get dequeued.
		 */
		blocking_lock_reply_error(blr, status);
		return True;
	}

	/* We finally got the lock, return success. */

	if (!(req = talloc(tmp_talloc_ctx(), struct smb_request))) {
		blocking_lock_reply_error(blr, NT_STATUS_NO_MEMORY);
		return True;
	}

	init_smb_request(req, (uint8 *)blr->inbuf);

	SCVAL(req->inbuf, smb_com, SMBtrans2);
	SSVAL(params,0,0);
	/* Fake up max_data_bytes here - we know it fits. */
	send_trans2_replies(req, params, 2, NULL, 0, 0xffff);
	return True;
}


/****************************************************************************
 Process a blocking lock SMB.
 Returns True if we want to be removed from the list.
*****************************************************************************/

static BOOL blocking_lock_record_process(blocking_lock_record *blr)
{
	switch(blr->com_type) {
		case SMBlockingX:
			return process_lockingX(blr);
		case SMBtrans2:
		case SMBtranss2:
			return process_trans2(blr);
		default:
			DEBUG(0,("blocking_lock_record_process: PANIC - unknown type on blocking lock queue - exiting.!\n"));
			exit_server("PANIC - unknown type on blocking lock queue");
	}
	return False; /* Keep compiler happy. */
}

/****************************************************************************
 Cancel entries by fnum from the blocking lock pending queue.
*****************************************************************************/

void cancel_pending_lock_requests_by_fid(files_struct *fsp, struct byte_range_lock *br_lck)
{
	blocking_lock_record *blr, *next = NULL;

	for(blr = blocking_lock_queue; blr; blr = next) {
		next = blr->next;
		if(blr->fsp->fnum == fsp->fnum) {
			unsigned char locktype = 0;

			if (blr->com_type == SMBlockingX) {
				locktype = CVAL(blr->inbuf,smb_vwv3);
			}

			if (br_lck) {
				DEBUG(10,("remove_pending_lock_requests_by_fid - removing request type %d for \
file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));

				brl_lock_cancel(br_lck,
					blr->lock_pid,
					procid_self(),
					blr->offset,
					blr->count,
					blr->lock_flav);

				blocking_lock_cancel(fsp,
					blr->lock_pid,
					blr->offset,
					blr->count,
					blr->lock_flav,
					locktype,
					NT_STATUS_RANGE_NOT_LOCKED);
			}
		}
	}
}

/****************************************************************************
 Delete entries by mid from the blocking lock pending queue. Always send reply.
*****************************************************************************/

void remove_pending_lock_requests_by_mid(int mid)
{
	blocking_lock_record *blr, *next = NULL;

	for(blr = blocking_lock_queue; blr; blr = next) {
		next = blr->next;
		if(SVAL(blr->inbuf,smb_mid) == mid) {
			files_struct *fsp = blr->fsp;
			struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);

			if (br_lck) {
				DEBUG(10,("remove_pending_lock_requests_by_mid - removing request type %d for \
file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));

				brl_lock_cancel(br_lck,
					blr->lock_pid,
					procid_self(),
					blr->offset,
					blr->count,
					blr->lock_flav);
				TALLOC_FREE(br_lck);
			}

			blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
			DLIST_REMOVE(blocking_lock_queue, blr);
			free_blocking_lock_record(blr);
		}
	}
}

/****************************************************************************
 Is this mid a blocking lock request on the queue ?
*****************************************************************************/

BOOL blocking_lock_was_deferred(int mid)
{
	blocking_lock_record *blr, *next = NULL;

	for(blr = blocking_lock_queue; blr; blr = next) {
		next = blr->next;
		if(SVAL(blr->inbuf,smb_mid) == mid) {
			return True;
		}
	}
	return False;
}

/****************************************************************************
  Set a flag as an unlock request affects one of our pending locks.
*****************************************************************************/

static void received_unlock_msg(struct messaging_context *msg,
				void *private_data,
				uint32_t msg_type,
				struct server_id server_id,
				DATA_BLOB *data)
{
	DEBUG(10,("received_unlock_msg\n"));
	process_blocking_lock_queue();
}

/****************************************************************************
 Process the blocking lock queue. Note that this is only called as root.
*****************************************************************************/

static void process_blocking_lock_queue(void)
{
	struct timeval tv_curr = timeval_current();
	blocking_lock_record *blr, *next = NULL;
	BOOL recalc_timeout = False;

	/*
	 * Go through the queue and see if we can get any of the locks.
	 */

	for (blr = blocking_lock_queue; blr; blr = next) {
		connection_struct *conn = NULL;
		uint16 vuid;
		files_struct *fsp = NULL;

		next = blr->next;

		/*
		 * Ensure we don't have any old chain_fsp values
		 * sitting around....
		 */
		chain_size = 0;
		file_chain_reset();
		fsp = blr->fsp;

		conn = conn_find(SVAL(blr->inbuf,smb_tid));
		vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID :
				SVAL(blr->inbuf,smb_uid);

		DEBUG(5,("process_blocking_lock_queue: examining pending lock fnum = %d for file %s\n",
			fsp->fnum, fsp->fsp_name ));

		if (!timeval_is_zero(&blr->expire_time) && timeval_compare(&blr->expire_time, &tv_curr) <= 0) {
			struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);

			/*
			 * Lock expired - throw away all previously
			 * obtained locks and return lock error.
			 */

			if (br_lck) {
				DEBUG(5,("process_blocking_lock_queue: pending lock fnum = %d for file %s timed out.\n",
					fsp->fnum, fsp->fsp_name ));

				brl_lock_cancel(br_lck,
					blr->lock_pid,
					procid_self(),
					blr->offset,
					blr->count,
					blr->lock_flav);
				TALLOC_FREE(br_lck);
			}

			blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
			DLIST_REMOVE(blocking_lock_queue, blr);
			free_blocking_lock_record(blr);
			recalc_timeout = True;
			continue;
		}

		if(!change_to_user(conn,vuid)) {
			struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);

			/*
			 * Remove the entry and return an error to the client.
			 */

			if (br_lck) {
				brl_lock_cancel(br_lck,
					blr->lock_pid,
					procid_self(),
					blr->offset,
					blr->count,
					blr->lock_flav);
				TALLOC_FREE(br_lck);
			}

			DEBUG(0,("process_blocking_lock_queue: Unable to become user vuid=%d.\n",
				vuid ));
			blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
			DLIST_REMOVE(blocking_lock_queue, blr);
			free_blocking_lock_record(blr);
			recalc_timeout = True;
			continue;
		}

		if(!set_current_service(conn,SVAL(blr->inbuf,smb_flg),True)) {
			struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);

			/*
			 * Remove the entry and return an error to the client.
			 */

			if (br_lck) {
				brl_lock_cancel(br_lck,
					blr->lock_pid,
					procid_self(),
					blr->offset,
					blr->count,
					blr->lock_flav);
				TALLOC_FREE(br_lck);
			}

			DEBUG(0,("process_blocking_lock_queue: Unable to become service Error was %s.\n", strerror(errno) ));
			blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
			DLIST_REMOVE(blocking_lock_queue, blr);
			free_blocking_lock_record(blr);
			recalc_timeout = True;
			change_to_root_user();
			continue;
		}

		/*
		 * Go through the remaining locks and try and obtain them.
		 * The call returns True if all locks were obtained successfully
		 * and False if we still need to wait.
		 */

		if(blocking_lock_record_process(blr)) {
			struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);

			if (br_lck) {
				brl_lock_cancel(br_lck,
					blr->lock_pid,
					procid_self(),
					blr->offset,
					blr->count,
					blr->lock_flav);
				TALLOC_FREE(br_lck);
			}

			DLIST_REMOVE(blocking_lock_queue, blr);
			free_blocking_lock_record(blr);
			recalc_timeout = True;
		}
		change_to_root_user();
	}

	if (recalc_timeout) {
		recalc_brl_timeout();
	}
}

/****************************************************************************
 Handle a cancel message. Lock already moved onto the cancel queue.
*****************************************************************************/

#define MSG_BLOCKING_LOCK_CANCEL_SIZE (sizeof(blocking_lock_record *) + sizeof(NTSTATUS))

static void process_blocking_lock_cancel_message(struct messaging_context *ctx,
						 void *private_data,
						 uint32_t msg_type,
						 struct server_id server_id,
						 DATA_BLOB *data)
{
	NTSTATUS err;
	const char *msg = (const char *)data->data;
	blocking_lock_record *blr;

	if (data->data == NULL) {
		smb_panic("process_blocking_lock_cancel_message: null msg");
	}

	if (data->length != MSG_BLOCKING_LOCK_CANCEL_SIZE) {
		DEBUG(0, ("process_blocking_lock_cancel_message: "
			  "Got invalid msg len %d\n", (int)data->length));
		smb_panic("process_blocking_lock_cancel_message: bad msg");
        }

	memcpy(&blr, msg, sizeof(blr));
	memcpy(&err, &msg[sizeof(blr)], sizeof(NTSTATUS));

	DEBUG(10,("process_blocking_lock_cancel_message: returning error %s\n",
		nt_errstr(err) ));

	blocking_lock_reply_error(blr, err);
	DLIST_REMOVE(blocking_lock_cancelled_queue, blr);
	free_blocking_lock_record(blr);
}

/****************************************************************************
 Send ourselves a blocking lock cancelled message. Handled asynchronously above.
*****************************************************************************/

BOOL blocking_lock_cancel(files_struct *fsp,
			uint32 lock_pid,
			SMB_BIG_UINT offset,
			SMB_BIG_UINT count,
			enum brl_flavour lock_flav,
			unsigned char locktype,
                        NTSTATUS err)
{
	static BOOL initialized;
	char msg[MSG_BLOCKING_LOCK_CANCEL_SIZE];
	blocking_lock_record *blr;

	if (!initialized) {
		/* Register our message. */
		messaging_register(smbd_messaging_context(), NULL,
				   MSG_SMB_BLOCKING_LOCK_CANCEL,
				   process_blocking_lock_cancel_message);

		initialized = True;
	}

	for (blr = blocking_lock_queue; blr; blr = blr->next) {
		if (fsp == blr->fsp &&
				lock_pid == blr->lock_pid &&
				offset == blr->offset &&
				count == blr->count &&
				lock_flav == blr->lock_flav) {
			break;
		}
	}

	if (!blr) {
		return False;
	}

	/* Check the flags are right. */
	if (blr->com_type == SMBlockingX &&
		(locktype & LOCKING_ANDX_LARGE_FILES) !=
			(CVAL(blr->inbuf,smb_vwv3) & LOCKING_ANDX_LARGE_FILES)) {
		return False;
	}

	/* Move to cancelled queue. */
	DLIST_REMOVE(blocking_lock_queue, blr);
	DLIST_ADD(blocking_lock_cancelled_queue, blr);

	/* Create the message. */
	memcpy(msg, &blr, sizeof(blr));
	memcpy(&msg[sizeof(blr)], &err, sizeof(NTSTATUS));

	messaging_send_buf(smbd_messaging_context(), procid_self(),
			   MSG_SMB_BLOCKING_LOCK_CANCEL,
			   (uint8 *)&msg, sizeof(msg));

	return True;
}