r17105: Fix the race Volker found - we had a non-locked
[samba.git] / source3 / smbd / blocking.c
1 /* 
2    Unix SMB/CIFS implementation.
3    Blocking Locking functions
4    Copyright (C) Jeremy Allison 1998-2003
5    
6    This program is free software; you can redistribute it and/or modify
7    it under the terms of the GNU General Public License as published by
8    the Free Software Foundation; either version 2 of the License, or
9    (at your option) any later version.
10    
11    This program is distributed in the hope that it will be useful,
12    but WITHOUT ANY WARRANTY; without even the implied warranty of
13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14    GNU General Public License for more details.
15    
16    You should have received a copy of the GNU General Public License
17    along with this program; if not, write to the Free Software
18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21 #include "includes.h"
22 #undef DBGC_CLASS
23 #define DBGC_CLASS DBGC_LOCKING
24
25 /****************************************************************************
26  This is the structure to queue to implement blocking locks.
27  notify. It consists of the requesting SMB and the expiry time.
28 *****************************************************************************/
29
30 typedef struct _blocking_lock_record {
31         struct _blocking_lock_record *next;
32         struct _blocking_lock_record *prev;
33         int com_type;
34         files_struct *fsp;
35         struct timeval expire_time;
36         int lock_num;
37         SMB_BIG_UINT offset;
38         SMB_BIG_UINT count;
39         uint32 lock_pid;
40         enum brl_flavour lock_flav;
41         enum brl_type lock_type;
42         char *inbuf;
43         int length;
44 } blocking_lock_record;
45
46 /* dlink list we store pending lock records on. */
47 static blocking_lock_record *blocking_lock_queue;
48
49 /* dlink list we move cancelled lock records onto. */
50 static blocking_lock_record *blocking_lock_cancelled_queue;
51
52 /****************************************************************************
53  Destructor for the above structure.
54 ****************************************************************************/
55
56 static void free_blocking_lock_record(blocking_lock_record *blr)
57 {
58         SAFE_FREE(blr->inbuf);
59         SAFE_FREE(blr);
60 }
61
62 /****************************************************************************
63  Determine if this is a secondary element of a chained SMB.
64   **************************************************************************/
65
66 static BOOL in_chained_smb(void)
67 {
68         return (chain_size != 0);
69 }
70
71 static void received_unlock_msg(int msg_type, struct process_id src,
72                                 void *buf, size_t len);
73
74 /****************************************************************************
75  Function to push a blocking lock request onto the lock queue.
76 ****************************************************************************/
77
78 BOOL push_blocking_lock_request( struct byte_range_lock *br_lck,
79                 char *inbuf, int length,
80                 files_struct *fsp,
81                 int lock_timeout,
82                 int lock_num,
83                 uint32 lock_pid,
84                 enum brl_type lock_type,
85                 enum brl_flavour lock_flav,
86                 SMB_BIG_UINT offset, SMB_BIG_UINT count)
87 {
88         static BOOL set_lock_msg;
89         blocking_lock_record *blr, *tmp;
90         NTSTATUS status;
91
92         if(in_chained_smb() ) {
93                 DEBUG(0,("push_blocking_lock_request: cannot queue a chained request (currently).\n"));
94                 return False;
95         }
96
97         /*
98          * Now queue an entry on the blocking lock queue. We setup
99          * the expiration time here.
100          */
101
102         if((blr = SMB_MALLOC_P(blocking_lock_record)) == NULL) {
103                 DEBUG(0,("push_blocking_lock_request: Malloc fail !\n" ));
104                 return False;
105         }
106
107         blr->next = NULL;
108         blr->prev = NULL;
109
110         if((blr->inbuf = (char *)SMB_MALLOC(length)) == NULL) {
111                 DEBUG(0,("push_blocking_lock_request: Malloc fail (2)!\n" ));
112                 SAFE_FREE(blr);
113                 return False;
114         }
115
116         blr->com_type = CVAL(inbuf,smb_com);
117         blr->fsp = fsp;
118         if (lock_timeout == -1) {
119                 blr->expire_time.tv_sec = 0;
120                 blr->expire_time.tv_usec = 0; /* Never expire. */
121         } else {
122                 blr->expire_time = timeval_current_ofs(lock_timeout/1000,
123                                         (lock_timeout % 1000) * 1000);
124         }
125         blr->lock_num = lock_num;
126         blr->lock_pid = lock_pid;
127         blr->lock_flav = lock_flav;
128         blr->lock_type = lock_type;
129         blr->offset = offset;
130         blr->count = count;
131         memcpy(blr->inbuf, inbuf, length);
132         blr->length = length;
133
134         /* Add a pending lock record for this. */
135         status = brl_lock(br_lck,
136                         lock_pid,
137                         procid_self(),
138                         offset,
139                         count,
140                         PENDING_LOCK,
141                         blr->lock_flav,
142                         lock_timeout ? True : False); /* blocking_lock. */
143
144         if (!NT_STATUS_IS_OK(status)) {
145                 DEBUG(0,("push_blocking_lock_request: failed to add PENDING_LOCK record.\n"));
146                 DLIST_REMOVE(blocking_lock_queue, blr);
147                 free_blocking_lock_record(blr);
148                 return False;
149         }
150
151         DLIST_ADD_END(blocking_lock_queue, blr, tmp);
152
153         /* Ensure we'll receive messages when this is unlocked. */
154         if (!set_lock_msg) {
155                 message_register(MSG_SMB_UNLOCK, received_unlock_msg);
156                 set_lock_msg = True;
157         }
158
159         DEBUG(3,("push_blocking_lock_request: lock request length=%d blocked with "
160                 "expiry time (%u sec. %u usec) (+%d msec) for fnum = %d, name = %s\n",
161                 length, (unsigned int)blr->expire_time.tv_sec,
162                 (unsigned int)blr->expire_time.tv_usec, lock_timeout,
163                 blr->fsp->fnum, blr->fsp->fsp_name ));
164
165         /* Push the MID of this packet on the signing queue. */
166         srv_defer_sign_response(SVAL(inbuf,smb_mid));
167
168         return True;
169 }
170
171 /****************************************************************************
172  Return a smd with a given size.
173 *****************************************************************************/
174
175 static void send_blocking_reply(char *outbuf, int outsize)
176 {
177         if(outsize > 4)
178                 smb_setlen(outbuf,outsize - 4);
179
180         if (!send_smb(smbd_server_fd(),outbuf))
181                 exit_server("send_blocking_reply: send_smb failed.");
182 }
183
184 /****************************************************************************
185  Return a lockingX success SMB.
186 *****************************************************************************/
187
188 static void reply_lockingX_success(blocking_lock_record *blr)
189 {
190         char *outbuf = get_OutBuffer();
191         int bufsize = BUFFER_SIZE;
192         char *inbuf = blr->inbuf;
193         int outsize = 0;
194
195         construct_reply_common(inbuf, outbuf);
196         set_message(outbuf,2,0,True);
197
198         /*
199          * As this message is a lockingX call we must handle
200          * any following chained message correctly.
201          * This is normally handled in construct_reply(),
202          * but as that calls switch_message, we can't use
203          * that here and must set up the chain info manually.
204          */
205
206         outsize = chain_reply(inbuf,outbuf,blr->length,bufsize);
207
208         outsize += chain_size;
209
210         send_blocking_reply(outbuf,outsize);
211 }
212
213 /****************************************************************************
214  Return a generic lock fail error blocking call.
215 *****************************************************************************/
216
217 static void generic_blocking_lock_error(blocking_lock_record *blr, NTSTATUS status)
218 {
219         char *outbuf = get_OutBuffer();
220         char *inbuf = blr->inbuf;
221         construct_reply_common(inbuf, outbuf);
222
223         /* whenever a timeout is given w2k maps LOCK_NOT_GRANTED to
224            FILE_LOCK_CONFLICT! (tridge) */
225         if (NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) {
226                 status = NT_STATUS_FILE_LOCK_CONFLICT;
227         }
228
229         if (NT_STATUS_EQUAL(status, NT_STATUS_FILE_LOCK_CONFLICT)) {
230                 /* Store the last lock error. */
231                 files_struct *fsp = blr->fsp;
232
233                 fsp->last_lock_failure.context.smbpid = blr->lock_pid;
234                 fsp->last_lock_failure.context.tid = fsp->conn->cnum;
235                 fsp->last_lock_failure.context.pid = procid_self();
236                 fsp->last_lock_failure.start = blr->offset;
237                 fsp->last_lock_failure.size = blr->count;
238                 fsp->last_lock_failure.fnum = fsp->fnum;
239                 fsp->last_lock_failure.lock_type = READ_LOCK; /* Don't care. */
240                 fsp->last_lock_failure.lock_flav = blr->lock_flav;
241         }
242
243         ERROR_NT(status);
244         if (!send_smb(smbd_server_fd(),outbuf)) {
245                 exit_server("generic_blocking_lock_error: send_smb failed.");
246         }
247 }
248
249 /****************************************************************************
250  Return a lock fail error for a lockingX call. Undo all the locks we have 
251  obtained first.
252 *****************************************************************************/
253
254 static void reply_lockingX_error(blocking_lock_record *blr, NTSTATUS status)
255 {
256         char *inbuf = blr->inbuf;
257         files_struct *fsp = blr->fsp;
258         uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
259         SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT) 0;
260         uint32 lock_pid;
261         unsigned char locktype = CVAL(inbuf,smb_vwv3);
262         BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
263         char *data;
264         int i;
265
266         data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
267         
268         /* 
269          * Data now points at the beginning of the list
270          * of smb_lkrng structs.
271          */
272
273         /*
274          * Ensure we don't do a remove on the lock that just failed,
275          * as under POSIX rules, if we have a lock already there, we
276          * will delete it (and we shouldn't) .....
277          */
278         
279         for(i = blr->lock_num - 1; i >= 0; i--) {
280                 BOOL err;
281                 
282                 lock_pid = get_lock_pid( data, i, large_file_format);
283                 count = get_lock_count( data, i, large_file_format);
284                 offset = get_lock_offset( data, i, large_file_format, &err);
285                 
286                 /*
287                  * We know err cannot be set as if it was the lock
288                  * request would never have been queued. JRA.
289                  */
290                 
291                 do_unlock(fsp,
292                         lock_pid,
293                         count,
294                         offset,
295                         WINDOWS_LOCK);
296         }
297         
298         generic_blocking_lock_error(blr, status);
299 }
300
301 /****************************************************************************
302  Return a lock fail error.
303 *****************************************************************************/
304
305 static void blocking_lock_reply_error(blocking_lock_record *blr, NTSTATUS status)
306 {
307         switch(blr->com_type) {
308         case SMBlockingX:
309                 reply_lockingX_error(blr, status);
310                 break;
311         case SMBtrans2:
312         case SMBtranss2:
313                 {
314                         char *outbuf = get_OutBuffer();
315                         char *inbuf = blr->inbuf;
316                         construct_reply_common(inbuf, outbuf);
317                         /* construct_reply_common has done us the favor to pre-fill the
318                          * command field with SMBtranss2 which is wrong :-)
319                          */
320                         SCVAL(outbuf,smb_com,SMBtrans2);
321                         ERROR_NT(status);
322                         if (!send_smb(smbd_server_fd(),outbuf)) {
323                                 exit_server("blocking_lock_reply_error: send_smb failed.");
324                         }
325                         break;
326                 }
327         default:
328                 DEBUG(0,("blocking_lock_reply_error: PANIC - unknown type on blocking lock queue - exiting.!\n"));
329                 exit_server("PANIC - unknown type on blocking lock queue");
330         }
331 }
332
333 /****************************************************************************
334  Attempt to finish off getting all pending blocking locks for a lockingX call.
335  Returns True if we want to be removed from the list.
336 *****************************************************************************/
337
338 static BOOL process_lockingX(blocking_lock_record *blr)
339 {
340         char *inbuf = blr->inbuf;
341         unsigned char locktype = CVAL(inbuf,smb_vwv3);
342         files_struct *fsp = blr->fsp;
343         uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
344         uint16 num_locks = SVAL(inbuf,smb_vwv7);
345         SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT)0;
346         uint32 lock_pid;
347         BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
348         char *data;
349         NTSTATUS status = NT_STATUS_OK;
350
351         data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
352
353         /* 
354          * Data now points at the beginning of the list
355          * of smb_lkrng structs.
356          */
357
358         for(; blr->lock_num < num_locks; blr->lock_num++) {
359                 struct byte_range_lock *br_lck = NULL;
360                 BOOL err;
361
362                 lock_pid = get_lock_pid( data, blr->lock_num, large_file_format);
363                 count = get_lock_count( data, blr->lock_num, large_file_format);
364                 offset = get_lock_offset( data, blr->lock_num, large_file_format, &err);
365                 
366                 /*
367                  * We know err cannot be set as if it was the lock
368                  * request would never have been queued. JRA.
369                  */
370                 errno = 0;
371                 br_lck = do_lock(fsp,
372                                 lock_pid,
373                                 count,
374                                 offset, 
375                                 ((locktype & LOCKING_ANDX_SHARED_LOCK) ?
376                                         READ_LOCK : WRITE_LOCK),
377                                 WINDOWS_LOCK,
378                                 True,
379                                 &status);
380
381                 TALLOC_FREE(br_lck);
382
383                 if (NT_STATUS_IS_ERR(status)) {
384                         break;
385                 }
386         }
387
388         if(blr->lock_num == num_locks) {
389                 /*
390                  * Success - we got all the locks.
391                  */
392                 
393                 DEBUG(3,("process_lockingX file = %s, fnum=%d type=%d num_locks=%d\n",
394                          fsp->fsp_name, fsp->fnum, (unsigned int)locktype, num_locks) );
395
396                 reply_lockingX_success(blr);
397                 return True;
398         } else if (!NT_STATUS_EQUAL(status,NT_STATUS_LOCK_NOT_GRANTED) &&
399                         !NT_STATUS_EQUAL(status,NT_STATUS_FILE_LOCK_CONFLICT)) {
400                         /*
401                          * We have other than a "can't get lock"
402                          * error. Free any locks we had and return an error.
403                          * Return True so we get dequeued.
404                          */
405                 
406                 blocking_lock_reply_error(blr, status);
407                 return True;
408         }
409
410         /*
411          * Still can't get all the locks - keep waiting.
412          */
413         
414         DEBUG(10,("process_lockingX: only got %d locks of %d needed for file %s, fnum = %d. \
415 Waiting....\n", 
416                   blr->lock_num, num_locks, fsp->fsp_name, fsp->fnum));
417         
418         return False;
419 }
420
421 /****************************************************************************
422  Attempt to get the posix lock request from a SMBtrans2 call.
423  Returns True if we want to be removed from the list.
424 *****************************************************************************/
425
426 static BOOL process_trans2(blocking_lock_record *blr)
427 {
428         extern int max_send;
429         char *inbuf = blr->inbuf;
430         char *outbuf;
431         char params[2];
432         NTSTATUS status;
433         struct byte_range_lock *br_lck = do_lock(blr->fsp,
434                                                 blr->lock_pid,
435                                                 blr->count,
436                                                 blr->offset,
437                                                 blr->lock_type,
438                                                 blr->lock_flav,
439                                                 True,
440                                                 &status);
441         TALLOC_FREE(br_lck);
442
443         if (!NT_STATUS_IS_OK(status)) {
444                 if (ERROR_WAS_LOCK_DENIED(status)) {
445                         /* Still can't get the lock, just keep waiting. */
446                         return False;
447                 }       
448                 /*
449                  * We have other than a "can't get lock"
450                  * error. Send an error and return True so we get dequeued.
451                  */
452                 blocking_lock_reply_error(blr, status);
453                 return True;
454         }
455
456         /* We finally got the lock, return success. */
457         outbuf = get_OutBuffer();
458         construct_reply_common(inbuf, outbuf);
459         SCVAL(outbuf,smb_com,SMBtrans2);
460         SSVAL(params,0,0);
461         send_trans2_replies(outbuf, max_send, params, 2, NULL, 0);
462         return True;
463 }
464
465
466 /****************************************************************************
467  Process a blocking lock SMB.
468  Returns True if we want to be removed from the list.
469 *****************************************************************************/
470
471 static BOOL blocking_lock_record_process(blocking_lock_record *blr)
472 {
473         switch(blr->com_type) {
474                 case SMBlockingX:
475                         return process_lockingX(blr);
476                 case SMBtrans2:
477                 case SMBtranss2:
478                         return process_trans2(blr);
479                 default:
480                         DEBUG(0,("blocking_lock_record_process: PANIC - unknown type on blocking lock queue - exiting.!\n"));
481                         exit_server("PANIC - unknown type on blocking lock queue");
482         }
483         return False; /* Keep compiler happy. */
484 }
485
486 /****************************************************************************
487  Cancel entries by fnum from the blocking lock pending queue.
488 *****************************************************************************/
489
490 void cancel_pending_lock_requests_by_fid(files_struct *fsp, struct byte_range_lock *br_lck)
491 {
492         blocking_lock_record *blr, *next = NULL;
493
494         for(blr = blocking_lock_queue; blr; blr = next) {
495                 next = blr->next;
496                 if(blr->fsp->fnum == fsp->fnum) {
497                         unsigned char locktype = 0;
498
499                         if (blr->com_type == SMBlockingX) {
500                                 locktype = CVAL(blr->inbuf,smb_vwv3);
501                         }
502
503                         if (br_lck) {
504                                 DEBUG(10,("remove_pending_lock_requests_by_fid - removing request type %d for \
505 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
506
507                                 brl_lock_cancel(br_lck,
508                                         blr->lock_pid,
509                                         procid_self(),
510                                         blr->offset,
511                                         blr->count,
512                                         blr->lock_flav);
513
514                                 blocking_lock_cancel(fsp,
515                                         blr->lock_pid,
516                                         blr->offset,
517                                         blr->count,
518                                         blr->lock_flav,
519                                         locktype,
520                                         NT_STATUS_RANGE_NOT_LOCKED);
521                         }
522                 }
523         }
524 }
525
526 /****************************************************************************
527  Delete entries by mid from the blocking lock pending queue. Always send reply.
528 *****************************************************************************/
529
530 void remove_pending_lock_requests_by_mid(int mid)
531 {
532         blocking_lock_record *blr, *next = NULL;
533
534         for(blr = blocking_lock_queue; blr; blr = next) {
535                 next = blr->next;
536                 if(SVAL(blr->inbuf,smb_mid) == mid) {
537                         files_struct *fsp = blr->fsp;
538                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
539
540                         if (br_lck) {
541                                 DEBUG(10,("remove_pending_lock_requests_by_mid - removing request type %d for \
542 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
543
544                                 brl_lock_cancel(br_lck,
545                                         blr->lock_pid,
546                                         procid_self(),
547                                         blr->offset,
548                                         blr->count,
549                                         blr->lock_flav);
550                                 TALLOC_FREE(br_lck);
551                         }
552
553                         blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
554                         DLIST_REMOVE(blocking_lock_queue, blr);
555                         free_blocking_lock_record(blr);
556                 }
557         }
558 }
559
560 /****************************************************************************
561   Set a flag as an unlock request affects one of our pending locks.
562 *****************************************************************************/
563
564 static void received_unlock_msg(int msg_type, struct process_id src,
565                                 void *buf, size_t len)
566 {
567         DEBUG(10,("received_unlock_msg\n"));
568         process_blocking_lock_queue();
569 }
570
571 /****************************************************************************
572  Return the number of milliseconds to the next blocking locks timeout, or default_timeout
573 *****************************************************************************/
574
575 unsigned int blocking_locks_timeout_ms(unsigned int default_timeout_ms)
576 {
577         unsigned int timeout_ms = default_timeout_ms;
578         struct timeval tv_curr;
579         SMB_BIG_INT min_tv_dif_us = 0x7FFFFFFF; /* A large +ve number. */
580         blocking_lock_record *blr = blocking_lock_queue;
581
582         /* note that we avoid the GetTimeOfDay() syscall if there are no blocking locks */
583         if (!blr) {
584                 return timeout_ms;
585         }
586
587         tv_curr = timeval_current();
588
589         for (; blr; blr = blr->next) {
590                 SMB_BIG_INT tv_dif_us;
591
592                 if (timeval_is_zero(&blr->expire_time)) {
593                         continue; /* Never timeout. */
594                 }
595
596                 tv_dif_us = usec_time_diff(&blr->expire_time, &tv_curr);
597                 min_tv_dif_us = MIN(min_tv_dif_us, tv_dif_us);
598         }
599
600         if (min_tv_dif_us < 0) {
601                 min_tv_dif_us = 0;
602         }
603
604         timeout_ms = (unsigned int)(min_tv_dif_us / (SMB_BIG_INT)1000);
605
606         if (timeout_ms < 1) {
607                 timeout_ms = 1;
608         }
609
610         DEBUG(10,("blocking_locks_timeout_ms: returning %u\n", timeout_ms));
611
612         return timeout_ms;
613 }
614
615 /****************************************************************************
616  Process the blocking lock queue. Note that this is only called as root.
617 *****************************************************************************/
618
619 void process_blocking_lock_queue(void)
620 {
621         struct timeval tv_curr = timeval_current();
622         blocking_lock_record *blr, *next = NULL;
623
624         /*
625          * Go through the queue and see if we can get any of the locks.
626          */
627
628         for (blr = blocking_lock_queue; blr; blr = next) {
629                 connection_struct *conn = NULL;
630                 uint16 vuid;
631                 files_struct *fsp = NULL;
632
633                 next = blr->next;
634
635                 /*
636                  * Ensure we don't have any old chain_fsp values
637                  * sitting around....
638                  */
639                 chain_size = 0;
640                 file_chain_reset();
641                 fsp = blr->fsp;
642
643                 conn = conn_find(SVAL(blr->inbuf,smb_tid));
644                 vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID :
645                                 SVAL(blr->inbuf,smb_uid);
646
647                 DEBUG(5,("process_blocking_lock_queue: examining pending lock fnum = %d for file %s\n",
648                         fsp->fnum, fsp->fsp_name ));
649
650                 if (!timeval_is_zero(&blr->expire_time) && timeval_compare(&blr->expire_time, &tv_curr) <= 0) {
651                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
652
653                         /*
654                          * Lock expired - throw away all previously
655                          * obtained locks and return lock error.
656                          */
657
658                         if (br_lck) {
659                                 DEBUG(5,("process_blocking_lock_queue: pending lock fnum = %d for file %s timed out.\n",
660                                         fsp->fnum, fsp->fsp_name ));
661
662                                 brl_lock_cancel(br_lck,
663                                         blr->lock_pid,
664                                         procid_self(),
665                                         blr->offset,
666                                         blr->count,
667                                         blr->lock_flav);
668                                 TALLOC_FREE(br_lck);
669                         }
670
671                         blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
672                         DLIST_REMOVE(blocking_lock_queue, blr);
673                         free_blocking_lock_record(blr);
674                         continue;
675                 }
676
677                 if(!change_to_user(conn,vuid)) {
678                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
679
680                         /*
681                          * Remove the entry and return an error to the client.
682                          */
683
684                         if (br_lck) {
685                                 brl_lock_cancel(br_lck,
686                                         blr->lock_pid,
687                                         procid_self(),
688                                         blr->offset,
689                                         blr->count,
690                                         blr->lock_flav);
691                                 TALLOC_FREE(br_lck);
692                         }
693
694                         DEBUG(0,("process_blocking_lock_queue: Unable to become user vuid=%d.\n",
695                                 vuid ));
696                         blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
697                         DLIST_REMOVE(blocking_lock_queue, blr);
698                         free_blocking_lock_record(blr);
699                         continue;
700                 }
701
702                 if(!set_current_service(conn,SVAL(blr->inbuf,smb_flg),True)) {
703                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
704
705                         /*
706                          * Remove the entry and return an error to the client.
707                          */
708
709                         if (br_lck) {
710                                 brl_lock_cancel(br_lck,
711                                         blr->lock_pid,
712                                         procid_self(),
713                                         blr->offset,
714                                         blr->count,
715                                         blr->lock_flav);
716                                 TALLOC_FREE(br_lck);
717                         }
718
719                         DEBUG(0,("process_blocking_lock_queue: Unable to become service Error was %s.\n", strerror(errno) ));
720                         blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
721                         DLIST_REMOVE(blocking_lock_queue, blr);
722                         free_blocking_lock_record(blr);
723                         change_to_root_user();
724                         continue;
725                 }
726
727                 /*
728                  * Go through the remaining locks and try and obtain them.
729                  * The call returns True if all locks were obtained successfully
730                  * and False if we still need to wait.
731                  */
732
733                 if(blocking_lock_record_process(blr)) {
734                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
735
736                         if (br_lck) {
737                                 brl_lock_cancel(br_lck,
738                                         blr->lock_pid,
739                                         procid_self(),
740                                         blr->offset,
741                                         blr->count,
742                                         blr->lock_flav);
743                                 TALLOC_FREE(br_lck);
744                         }
745
746                         DLIST_REMOVE(blocking_lock_queue, blr);
747                         free_blocking_lock_record(blr);
748                 }
749                 change_to_root_user();
750         }
751 }
752
753 /****************************************************************************
754  Handle a cancel message. Lock already moved onto the cancel queue.
755 *****************************************************************************/
756
757 #define MSG_BLOCKING_LOCK_CANCEL_SIZE (sizeof(blocking_lock_record *) + sizeof(NTSTATUS))
758
759 static void process_blocking_lock_cancel_message(int msg_type, struct process_id src,
760                                          void *buf, size_t len)
761 {
762         NTSTATUS err;
763         const char *msg = (const char *)buf;
764         blocking_lock_record *blr;
765
766         if (buf == NULL) {
767                 smb_panic("process_blocking_lock_cancel_message: null msg\n");
768         }
769
770         if (len != MSG_BLOCKING_LOCK_CANCEL_SIZE) {
771                 DEBUG(0, ("process_blocking_lock_cancel_message: "
772                         "Got invalid msg len %d\n", (int)len));
773                 smb_panic("process_blocking_lock_cancel_message: bad msg\n");
774         }
775
776         memcpy(&blr, msg, sizeof(blr));
777         memcpy(&err, &msg[sizeof(blr)], sizeof(NTSTATUS));
778
779         DEBUG(10,("process_blocking_lock_cancel_message: returning error %s\n",
780                 nt_errstr(err) ));
781
782         blocking_lock_reply_error(blr, err);
783         DLIST_REMOVE(blocking_lock_cancelled_queue, blr);
784         free_blocking_lock_record(blr);
785 }
786
787 /****************************************************************************
788  Send ourselves a blocking lock cancelled message. Handled asynchronously above.
789 *****************************************************************************/
790
791 BOOL blocking_lock_cancel(files_struct *fsp,
792                         uint32 lock_pid,
793                         SMB_BIG_UINT offset,
794                         SMB_BIG_UINT count,
795                         enum brl_flavour lock_flav,
796                         unsigned char locktype,
797                         NTSTATUS err)
798 {
799         static BOOL initialized;
800         char msg[MSG_BLOCKING_LOCK_CANCEL_SIZE];
801         blocking_lock_record *blr;
802
803         if (!initialized) {
804                 /* Register our message. */
805                 message_register(MSG_SMB_BLOCKING_LOCK_CANCEL,
806                                 process_blocking_lock_cancel_message);
807
808                 initialized = True;
809         }
810
811         for (blr = blocking_lock_queue; blr; blr = blr->next) {
812                 if (fsp == blr->fsp &&
813                                 lock_pid == blr->lock_pid &&
814                                 offset == blr->offset &&
815                                 count == blr->count &&
816                                 lock_flav == blr->lock_flav) {
817                         break;
818                 }
819         }
820
821         if (!blr) {
822                 return False;
823         }
824
825         /* Check the flags are right. */
826         if (blr->com_type == SMBlockingX &&
827                 (locktype & LOCKING_ANDX_LARGE_FILES) !=
828                         (CVAL(blr->inbuf,smb_vwv3) & LOCKING_ANDX_LARGE_FILES)) {
829                 return False;
830         }
831
832         /* Move to cancelled queue. */
833         DLIST_REMOVE(blocking_lock_queue, blr);
834         DLIST_ADD(blocking_lock_cancelled_queue, blr);
835
836         /* Create the message. */
837         memcpy(msg, &blr, sizeof(blr));
838         memcpy(&msg[sizeof(blr)], &err, sizeof(NTSTATUS));
839
840         /* Don't need to be root here as we're only ever
841                 sending to ourselves. */
842
843         message_send_pid(pid_to_procid(sys_getpid()),
844                         MSG_SMB_BLOCKING_LOCK_CANCEL,
845                         &msg, sizeof(msg), True);
846
847         return True;
848 }