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 3 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, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #undef DBGC_CLASS
  22 #define DBGC_CLASS DBGC_LOCKING
  23
  24 /****************************************************************************
  25  This is the structure to queue to implement blocking locks.
  26  notify. It consists of the requesting SMB and the expiry time.
  27 *****************************************************************************/
  28
  29 typedef struct _blocking_lock_record {
  30         struct _blocking_lock_record *next;
  31         struct _blocking_lock_record *prev;
  32         int com_type;
  33         files_struct *fsp;
  34         struct timeval expire_time;
  35         int lock_num;
  36         SMB_BIG_UINT offset;
  37         SMB_BIG_UINT count;
  38         uint32 lock_pid;
  39         uint32 blocking_pid; /* PID that blocks us. */
  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 /* The event that makes us process our blocking lock queue */
  53 static struct timed_event *brl_timeout;
  54
  55 /****************************************************************************
  56  Destructor for the above structure.
  57 ****************************************************************************/
  58
  59 static void free_blocking_lock_record(blocking_lock_record *blr)
  60 {
  61         SAFE_FREE(blr->inbuf);
  62         SAFE_FREE(blr);
  63 }
  64
  65 /****************************************************************************
  66  Determine if this is a secondary element of a chained SMB.
  67   **************************************************************************/
  68
  69 static bool in_chained_smb(void)
  70 {
  71         return (chain_size != 0);
  72 }
  73
  74 static void received_unlock_msg(struct messaging_context *msg,
  75                                 void *private_data,
  76                                 uint32_t msg_type,
  77                                 struct server_id server_id,
  78                                 DATA_BLOB *data);
  79 static void process_blocking_lock_queue(void);
  80
  81 static void brl_timeout_fn(struct event_context *event_ctx,
  82                            struct timed_event *te,
  83                            const struct timeval *now,
  84                            void *private_data)
  85 {
  86         SMB_ASSERT(brl_timeout == te);
  87         TALLOC_FREE(brl_timeout);
  88
  89         change_to_root_user();  /* TODO: Possibly run all timed events as
  90                                  * root */
  91
  92         process_blocking_lock_queue();
  93 }
  94
  95 /****************************************************************************
  96  After a change to blocking_lock_queue, recalculate the timed_event for the
  97  next processing.
  98 ****************************************************************************/
  99
 100 static bool recalc_brl_timeout(void)
 101 {
 102         blocking_lock_record *brl;
 103         struct timeval next_timeout;
 104
 105         TALLOC_FREE(brl_timeout);
 106
 107         next_timeout = timeval_zero();
 108
 109         for (brl = blocking_lock_queue; brl; brl = brl->next) {
 110                 if (timeval_is_zero(&brl->expire_time)) {
 111                         /*
 112                          * If we're blocked on pid 0xFFFFFFFF this is
 113                          * a POSIX lock, so calculate a timeout of
 114                          * 10 seconds into the future.
 115                          */
 116                         if (brl->blocking_pid == 0xFFFFFFFF) {
 117                                 struct timeval psx_to = timeval_current_ofs(10, 0);
 118                                 next_timeout = timeval_min(&next_timeout, &psx_to);
 119                         }
 120
 121                         continue;
 122                 }
 123
 124                 if (timeval_is_zero(&next_timeout)) {
 125                         next_timeout = brl->expire_time;
 126                 }
 127                 else {
 128                         next_timeout = timeval_min(&next_timeout,
 129                                                    &brl->expire_time);
 130                 }
 131         }
 132
 133         if (timeval_is_zero(&next_timeout)) {
 134                 return True;
 135         }
 136
 137         if (!(brl_timeout = event_add_timed(smbd_event_context(), NULL,
 138                                             next_timeout, "brl_timeout",
 139                                             brl_timeout_fn, NULL))) {
 140                 return False;
 141         }
 142
 143         return True;
 144 }
 145
 146
 147 /****************************************************************************
 148  Function to push a blocking lock request onto the lock queue.
 149 ****************************************************************************/
 150
 151 bool push_blocking_lock_request( struct byte_range_lock *br_lck,
 152                 const char *inbuf, int length,
 153                 files_struct *fsp,
 154                 int lock_timeout,
 155                 int lock_num,
 156                 uint32 lock_pid,
 157                 enum brl_type lock_type,
 158                 enum brl_flavour lock_flav,
 159                 SMB_BIG_UINT offset,
 160                 SMB_BIG_UINT count,
 161                 uint32 blocking_pid)
 162 {
 163         static bool set_lock_msg;
 164         blocking_lock_record *blr;
 165         NTSTATUS status;
 166
 167         if(in_chained_smb() ) {
 168                 DEBUG(0,("push_blocking_lock_request: cannot queue a chained request (currently).\n"));
 169                 return False;
 170         }
 171
 172         /*
 173          * Now queue an entry on the blocking lock queue. We setup
 174          * the expiration time here.
 175          */
 176
 177         if((blr = SMB_MALLOC_P(blocking_lock_record)) == NULL) {
 178                 DEBUG(0,("push_blocking_lock_request: Malloc fail !\n" ));
 179                 return False;
 180         }
 181
 182         blr->next = NULL;
 183         blr->prev = NULL;
 184
 185         if((blr->inbuf = (char *)SMB_MALLOC(length)) == NULL) {
 186                 DEBUG(0,("push_blocking_lock_request: Malloc fail (2)!\n" ));
 187                 SAFE_FREE(blr);
 188                 return False;
 189         }
 190
 191         blr->com_type = CVAL(inbuf,smb_com);
 192         blr->fsp = fsp;
 193         if (lock_timeout == -1) {
 194                 blr->expire_time.tv_sec = 0;
 195                 blr->expire_time.tv_usec = 0; /* Never expire. */
 196         } else {
 197                 blr->expire_time = timeval_current_ofs(lock_timeout/1000,
 198                                         (lock_timeout % 1000) * 1000);
 199         }
 200         blr->lock_num = lock_num;
 201         blr->lock_pid = lock_pid;
 202         blr->blocking_pid = blocking_pid;
 203         blr->lock_flav = lock_flav;
 204         blr->lock_type = lock_type;
 205         blr->offset = offset;
 206         blr->count = count;
 207         memcpy(blr->inbuf, inbuf, length);
 208         blr->length = length;
 209
 210         /* Add a pending lock record for this. */
 211         status = brl_lock(smbd_messaging_context(), br_lck,
 212                         lock_pid,
 213                         procid_self(),
 214                         offset,
 215                         count,
 216                         lock_type == READ_LOCK ? PENDING_READ_LOCK : PENDING_WRITE_LOCK,
 217                         blr->lock_flav,
 218                         lock_timeout ? True : False, /* blocking_lock. */
 219                         NULL);
 220
 221         if (!NT_STATUS_IS_OK(status)) {
 222                 DEBUG(0,("push_blocking_lock_request: failed to add PENDING_LOCK record.\n"));
 223                 DLIST_REMOVE(blocking_lock_queue, blr);
 224                 free_blocking_lock_record(blr);
 225                 return False;
 226         }
 227
 228         DLIST_ADD_END(blocking_lock_queue, blr, blocking_lock_record *);
 229         recalc_brl_timeout();
 230
 231         /* Ensure we'll receive messages when this is unlocked. */
 232         if (!set_lock_msg) {
 233                 messaging_register(smbd_messaging_context(), NULL,
 234                                    MSG_SMB_UNLOCK, received_unlock_msg);
 235                 set_lock_msg = True;
 236         }
 237
 238         DEBUG(3,("push_blocking_lock_request: lock request length=%d blocked with "
 239                 "expiry time (%u sec. %u usec) (+%d msec) for fnum = %d, name = %s\n",
 240                 length, (unsigned int)blr->expire_time.tv_sec,
 241                 (unsigned int)blr->expire_time.tv_usec, lock_timeout,
 242                 blr->fsp->fnum, blr->fsp->fsp_name ));
 243
 244         /* Push the MID of this packet on the signing queue. */
 245         srv_defer_sign_response(SVAL(inbuf,smb_mid));
 246
 247         return True;
 248 }
 249
 250 /****************************************************************************
 251  Return a lockingX success SMB.
 252 *****************************************************************************/
 253
 254 static void reply_lockingX_success(blocking_lock_record *blr)
 255 {
 256         struct smb_request *req;
 257
 258         if (!(req = talloc(talloc_tos(), struct smb_request))) {
 259                 smb_panic("Could not allocate smb_request");
 260         }
 261
 262         init_smb_request(req, (uint8 *)blr->inbuf);
 263         reply_outbuf(req, 2, 0);
 264
 265         /*
 266          * As this message is a lockingX call we must handle
 267          * any following chained message correctly.
 268          * This is normally handled in construct_reply(),
 269          * but as that calls switch_message, we can't use
 270          * that here and must set up the chain info manually.
 271          */
 272
 273         chain_reply(req);
 274
 275         if (!send_smb(smbd_server_fd(),(char *)req->outbuf)) {
 276                 exit_server_cleanly("send_blocking_reply: send_smb failed.");
 277         }
 278 }
 279
 280 /****************************************************************************
 281  Return a generic lock fail error blocking call.
 282 *****************************************************************************/
 283
 284 static void generic_blocking_lock_error(blocking_lock_record *blr, NTSTATUS status)
 285 {
 286         char outbuf[smb_size];
 287         char *inbuf = blr->inbuf;
 288
 289         construct_reply_common(inbuf, outbuf);
 290
 291         /* whenever a timeout is given w2k maps LOCK_NOT_GRANTED to
 292            FILE_LOCK_CONFLICT! (tridge) */
 293         if (NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) {
 294                 status = NT_STATUS_FILE_LOCK_CONFLICT;
 295         }
 296
 297         if (NT_STATUS_EQUAL(status, NT_STATUS_FILE_LOCK_CONFLICT)) {
 298                 /* Store the last lock error. */
 299                 files_struct *fsp = blr->fsp;
 300
 301                 fsp->last_lock_failure.context.smbpid = blr->lock_pid;
 302                 fsp->last_lock_failure.context.tid = fsp->conn->cnum;
 303                 fsp->last_lock_failure.context.pid = procid_self();
 304                 fsp->last_lock_failure.start = blr->offset;
 305                 fsp->last_lock_failure.size = blr->count;
 306                 fsp->last_lock_failure.fnum = fsp->fnum;
 307                 fsp->last_lock_failure.lock_type = READ_LOCK; /* Don't care. */
 308                 fsp->last_lock_failure.lock_flav = blr->lock_flav;
 309         }
 310
 311         ERROR_NT(status);
 312         if (!send_smb(smbd_server_fd(),outbuf)) {
 313                 exit_server_cleanly("generic_blocking_lock_error: send_smb failed.");
 314         }
 315 }
 316
 317 /****************************************************************************
 318  Return a lock fail error for a lockingX call. Undo all the locks we have
 319  obtained first.
 320 *****************************************************************************/
 321
 322 static void reply_lockingX_error(blocking_lock_record *blr, NTSTATUS status)
 323 {
 324         char *inbuf = blr->inbuf;
 325         files_struct *fsp = blr->fsp;
 326         uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
 327         SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT) 0;
 328         uint32 lock_pid;
 329         unsigned char locktype = CVAL(inbuf,smb_vwv3);
 330         bool large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
 331         char *data;
 332         int i;
 333
 334         data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
 335
 336         /*
 337          * Data now points at the beginning of the list
 338          * of smb_lkrng structs.
 339          */
 340
 341         /*
 342          * Ensure we don't do a remove on the lock that just failed,
 343          * as under POSIX rules, if we have a lock already there, we
 344          * will delete it (and we shouldn't) .....
 345          */
 346
 347         for(i = blr->lock_num - 1; i >= 0; i--) {
 348                 bool err;
 349
 350                 lock_pid = get_lock_pid( data, i, large_file_format);
 351                 count = get_lock_count( data, i, large_file_format);
 352                 offset = get_lock_offset( data, i, large_file_format, &err);
 353
 354                 /*
 355                  * We know err cannot be set as if it was the lock
 356                  * request would never have been queued. JRA.
 357                  */
 358
 359                 do_unlock(smbd_messaging_context(),
 360                         fsp,
 361                         lock_pid,
 362                         count,
 363                         offset,
 364                         WINDOWS_LOCK);
 365         }
 366
 367         generic_blocking_lock_error(blr, status);
 368 }
 369
 370 /****************************************************************************
 371  Return a lock fail error.
 372 *****************************************************************************/
 373
 374 static void blocking_lock_reply_error(blocking_lock_record *blr, NTSTATUS status)
 375 {
 376         switch(blr->com_type) {
 377         case SMBlockingX:
 378                 reply_lockingX_error(blr, status);
 379                 break;
 380         case SMBtrans2:
 381         case SMBtranss2:
 382                 {
 383                         char outbuf[smb_size];
 384                         char *inbuf = blr->inbuf;
 385                         construct_reply_common(inbuf, outbuf);
 386                         /* construct_reply_common has done us the favor to pre-fill the
 387                          * command field with SMBtranss2 which is wrong :-)
 388                          */
 389                         SCVAL(outbuf,smb_com,SMBtrans2);
 390                         ERROR_NT(status);
 391                         if (!send_smb(smbd_server_fd(),outbuf)) {
 392                                 exit_server_cleanly("blocking_lock_reply_error: send_smb failed.");
 393                         }
 394                         break;
 395                 }
 396         default:
 397                 DEBUG(0,("blocking_lock_reply_error: PANIC - unknown type on blocking lock queue - exiting.!\n"));
 398                 exit_server("PANIC - unknown type on blocking lock queue");
 399         }
 400 }
 401
 402 /****************************************************************************
 403  Attempt to finish off getting all pending blocking locks for a lockingX call.
 404  Returns True if we want to be removed from the list.
 405 *****************************************************************************/
 406
 407 static bool process_lockingX(blocking_lock_record *blr)
 408 {
 409         char *inbuf = blr->inbuf;
 410         unsigned char locktype = CVAL(inbuf,smb_vwv3);
 411         files_struct *fsp = blr->fsp;
 412         uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
 413         uint16 num_locks = SVAL(inbuf,smb_vwv7);
 414         SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT)0;
 415         uint32 lock_pid;
 416         bool large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
 417         char *data;
 418         NTSTATUS status = NT_STATUS_OK;
 419
 420         data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
 421
 422         /*
 423          * Data now points at the beginning of the list
 424          * of smb_lkrng structs.
 425          */
 426
 427         for(; blr->lock_num < num_locks; blr->lock_num++) {
 428                 struct byte_range_lock *br_lck = NULL;
 429                 bool err;
 430
 431                 lock_pid = get_lock_pid( data, blr->lock_num, large_file_format);
 432                 count = get_lock_count( data, blr->lock_num, large_file_format);
 433                 offset = get_lock_offset( data, blr->lock_num, large_file_format, &err);
 434
 435                 /*
 436                  * We know err cannot be set as if it was the lock
 437                  * request would never have been queued. JRA.
 438                  */
 439                 errno = 0;
 440                 br_lck = do_lock(smbd_messaging_context(),
 441                                 fsp,
 442                                 lock_pid,
 443                                 count,
 444                                 offset,
 445                                 ((locktype & LOCKING_ANDX_SHARED_LOCK) ?
 446                                         READ_LOCK : WRITE_LOCK),
 447                                 WINDOWS_LOCK,
 448                                 True,
 449                                 &status,
 450                                 &blr->blocking_pid);
 451
 452                 TALLOC_FREE(br_lck);
 453
 454                 if (NT_STATUS_IS_ERR(status)) {
 455                         break;
 456                 }
 457         }
 458
 459         if(blr->lock_num == num_locks) {
 460                 /*
 461                  * Success - we got all the locks.
 462                  */
 463
 464                 DEBUG(3,("process_lockingX file = %s, fnum=%d type=%d num_locks=%d\n",
 465                          fsp->fsp_name, fsp->fnum, (unsigned int)locktype, num_locks) );
 466
 467                 reply_lockingX_success(blr);
 468                 return True;
 469         } else if (!NT_STATUS_EQUAL(status,NT_STATUS_LOCK_NOT_GRANTED) &&
 470                         !NT_STATUS_EQUAL(status,NT_STATUS_FILE_LOCK_CONFLICT)) {
 471                         /*
 472                          * We have other than a "can't get lock"
 473                          * error. Free any locks we had and return an error.
 474                          * Return True so we get dequeued.
 475                          */
 476
 477                 blocking_lock_reply_error(blr, status);
 478                 return True;
 479         }
 480
 481         /*
 482          * Still can't get all the locks - keep waiting.
 483          */
 484
 485         DEBUG(10,("process_lockingX: only got %d locks of %d needed for file %s, fnum = %d. \
 486 Waiting....\n",
 487                   blr->lock_num, num_locks, fsp->fsp_name, fsp->fnum));
 488
 489         return False;
 490 }
 491
 492 /****************************************************************************
 493  Attempt to get the posix lock request from a SMBtrans2 call.
 494  Returns True if we want to be removed from the list.
 495 *****************************************************************************/
 496
 497 static bool process_trans2(blocking_lock_record *blr)
 498 {
 499         struct smb_request *req;
 500         char params[2];
 501         NTSTATUS status;
 502         struct byte_range_lock *br_lck = do_lock(smbd_messaging_context(),
 503                                                 blr->fsp,
 504                                                 blr->lock_pid,
 505                                                 blr->count,
 506                                                 blr->offset,
 507                                                 blr->lock_type,
 508                                                 blr->lock_flav,
 509                                                 True,
 510                                                 &status,
 511                                                 &blr->blocking_pid);
 512         TALLOC_FREE(br_lck);
 513
 514         if (!NT_STATUS_IS_OK(status)) {
 515                 if (ERROR_WAS_LOCK_DENIED(status)) {
 516                         /* Still can't get the lock, just keep waiting. */
 517                         return False;
 518                 }
 519                 /*
 520                  * We have other than a "can't get lock"
 521                  * error. Send an error and return True so we get dequeued.
 522                  */
 523                 blocking_lock_reply_error(blr, status);
 524                 return True;
 525         }
 526
 527         /* We finally got the lock, return success. */
 528
 529         if (!(req = talloc(talloc_tos(), struct smb_request))) {
 530                 blocking_lock_reply_error(blr, NT_STATUS_NO_MEMORY);
 531                 return True;
 532         }
 533
 534         init_smb_request(req, (uint8 *)blr->inbuf);
 535
 536         SCVAL(req->inbuf, smb_com, SMBtrans2);
 537         SSVAL(params,0,0);
 538         /* Fake up max_data_bytes here - we know it fits. */
 539         send_trans2_replies(req, params, 2, NULL, 0, 0xffff);
 540         return True;
 541 }
 542
 543
 544 /****************************************************************************
 545  Process a blocking lock SMB.
 546  Returns True if we want to be removed from the list.
 547 *****************************************************************************/
 548
 549 static bool blocking_lock_record_process(blocking_lock_record *blr)
 550 {
 551         switch(blr->com_type) {
 552                 case SMBlockingX:
 553                         return process_lockingX(blr);
 554                 case SMBtrans2:
 555                 case SMBtranss2:
 556                         return process_trans2(blr);
 557                 default:
 558                         DEBUG(0,("blocking_lock_record_process: PANIC - unknown type on blocking lock queue - exiting.!\n"));
 559                         exit_server("PANIC - unknown type on blocking lock queue");
 560         }
 561         return False; /* Keep compiler happy. */
 562 }
 563
 564 /****************************************************************************
 565  Cancel entries by fnum from the blocking lock pending queue.
 566 *****************************************************************************/
 567
 568 void cancel_pending_lock_requests_by_fid(files_struct *fsp, struct byte_range_lock *br_lck)
 569 {
 570         blocking_lock_record *blr, *next = NULL;
 571
 572         for(blr = blocking_lock_queue; blr; blr = next) {
 573                 next = blr->next;
 574                 if(blr->fsp->fnum == fsp->fnum) {
 575                         unsigned char locktype = 0;
 576
 577                         if (blr->com_type == SMBlockingX) {
 578                                 locktype = CVAL(blr->inbuf,smb_vwv3);
 579                         }
 580
 581                         if (br_lck) {
 582                                 DEBUG(10,("remove_pending_lock_requests_by_fid - removing request type %d for \
 583 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
 584
 585                                 brl_lock_cancel(br_lck,
 586                                         blr->lock_pid,
 587                                         procid_self(),
 588                                         blr->offset,
 589                                         blr->count,
 590                                         blr->lock_flav);
 591
 592                                 blocking_lock_cancel(fsp,
 593                                         blr->lock_pid,
 594                                         blr->offset,
 595                                         blr->count,
 596                                         blr->lock_flav,
 597                                         locktype,
 598                                         NT_STATUS_RANGE_NOT_LOCKED);
 599                         }
 600                 }
 601         }
 602 }
 603
 604 /****************************************************************************
 605  Delete entries by mid from the blocking lock pending queue. Always send reply.
 606 *****************************************************************************/
 607
 608 void remove_pending_lock_requests_by_mid(int mid)
 609 {
 610         blocking_lock_record *blr, *next = NULL;
 611
 612         for(blr = blocking_lock_queue; blr; blr = next) {
 613                 next = blr->next;
 614                 if(SVAL(blr->inbuf,smb_mid) == mid) {
 615                         files_struct *fsp = blr->fsp;
 616                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
 617
 618                         if (br_lck) {
 619                                 DEBUG(10,("remove_pending_lock_requests_by_mid - removing request type %d for \
 620 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
 621
 622                                 brl_lock_cancel(br_lck,
 623                                         blr->lock_pid,
 624                                         procid_self(),
 625                                         blr->offset,
 626                                         blr->count,
 627                                         blr->lock_flav);
 628                                 TALLOC_FREE(br_lck);
 629                         }
 630
 631                         blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
 632                         DLIST_REMOVE(blocking_lock_queue, blr);
 633                         free_blocking_lock_record(blr);
 634                 }
 635         }
 636 }
 637
 638 /****************************************************************************
 639  Is this mid a blocking lock request on the queue ?
 640 *****************************************************************************/
 641
 642 bool blocking_lock_was_deferred(int mid)
 643 {
 644         blocking_lock_record *blr, *next = NULL;
 645
 646         for(blr = blocking_lock_queue; blr; blr = next) {
 647                 next = blr->next;
 648                 if(SVAL(blr->inbuf,smb_mid) == mid) {
 649                         return True;
 650                 }
 651         }
 652         return False;
 653 }
 654
 655 /****************************************************************************
 656   Set a flag as an unlock request affects one of our pending locks.
 657 *****************************************************************************/
 658
 659 static void received_unlock_msg(struct messaging_context *msg,
 660                                 void *private_data,
 661                                 uint32_t msg_type,
 662                                 struct server_id server_id,
 663                                 DATA_BLOB *data)
 664 {
 665         DEBUG(10,("received_unlock_msg\n"));
 666         process_blocking_lock_queue();
 667 }
 668
 669 /****************************************************************************
 670  Process the blocking lock queue. Note that this is only called as root.
 671 *****************************************************************************/
 672
 673 static void process_blocking_lock_queue(void)
 674 {
 675         struct timeval tv_curr = timeval_current();
 676         blocking_lock_record *blr, *next = NULL;
 677         bool recalc_timeout = False;
 678
 679         /*
 680          * Go through the queue and see if we can get any of the locks.
 681          */
 682
 683         for (blr = blocking_lock_queue; blr; blr = next) {
 684                 connection_struct *conn = NULL;
 685                 uint16 vuid;
 686                 files_struct *fsp = NULL;
 687
 688                 next = blr->next;
 689
 690                 /*
 691                  * Ensure we don't have any old chain_fsp values
 692                  * sitting around....
 693                  */
 694                 chain_size = 0;
 695                 file_chain_reset();
 696                 fsp = blr->fsp;
 697
 698                 conn = conn_find(SVAL(blr->inbuf,smb_tid));
 699                 vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID :
 700                                 SVAL(blr->inbuf,smb_uid);
 701
 702                 DEBUG(5,("process_blocking_lock_queue: examining pending lock fnum = %d for file %s\n",
 703                         fsp->fnum, fsp->fsp_name ));
 704
 705                 if(!change_to_user(conn,vuid)) {
 706                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
 707
 708                         /*
 709                          * Remove the entry and return an error to the client.
 710                          */
 711
 712                         if (br_lck) {
 713                                 brl_lock_cancel(br_lck,
 714                                         blr->lock_pid,
 715                                         procid_self(),
 716                                         blr->offset,
 717                                         blr->count,
 718                                         blr->lock_flav);
 719                                 TALLOC_FREE(br_lck);
 720                         }
 721
 722                         DEBUG(0,("process_blocking_lock_queue: Unable to become user vuid=%d.\n",
 723                                 vuid ));
 724                         blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
 725                         DLIST_REMOVE(blocking_lock_queue, blr);
 726                         free_blocking_lock_record(blr);
 727                         recalc_timeout = True;
 728                         continue;
 729                 }
 730
 731                 if(!set_current_service(conn,SVAL(blr->inbuf,smb_flg),True)) {
 732                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
 733
 734                         /*
 735                          * Remove the entry and return an error to the client.
 736                          */
 737
 738                         if (br_lck) {
 739                                 brl_lock_cancel(br_lck,
 740                                         blr->lock_pid,
 741                                         procid_self(),
 742                                         blr->offset,
 743                                         blr->count,
 744                                         blr->lock_flav);
 745                                 TALLOC_FREE(br_lck);
 746                         }
 747
 748                         DEBUG(0,("process_blocking_lock_queue: Unable to become service Error was %s.\n", strerror(errno) ));
 749                         blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
 750                         DLIST_REMOVE(blocking_lock_queue, blr);
 751                         free_blocking_lock_record(blr);
 752                         recalc_timeout = True;
 753                         change_to_root_user();
 754                         continue;
 755                 }
 756
 757                 /*
 758                  * Go through the remaining locks and try and obtain them.
 759                  * The call returns True if all locks were obtained successfully
 760                  * and False if we still need to wait.
 761                  */
 762
 763                 if(blocking_lock_record_process(blr)) {
 764                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
 765
 766                         if (br_lck) {
 767                                 brl_lock_cancel(br_lck,
 768                                         blr->lock_pid,
 769                                         procid_self(),
 770                                         blr->offset,
 771                                         blr->count,
 772                                         blr->lock_flav);
 773                                 TALLOC_FREE(br_lck);
 774                         }
 775
 776                         DLIST_REMOVE(blocking_lock_queue, blr);
 777                         free_blocking_lock_record(blr);
 778                         recalc_timeout = True;
 779                         change_to_root_user();
 780                         continue;
 781                 }
 782
 783                 change_to_root_user();
 784
 785                 /*
 786                  * We couldn't get the locks for this record on the list.
 787                  * If the time has expired, return a lock error.
 788                  */
 789
 790                 if (!timeval_is_zero(&blr->expire_time) && timeval_compare(&blr->expire_time, &tv_curr) <= 0) {
 791                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
 792
 793                         /*
 794                          * Lock expired - throw away all previously
 795                          * obtained locks and return lock error.
 796                          */
 797
 798                         if (br_lck) {
 799                                 DEBUG(5,("process_blocking_lock_queue: pending lock fnum = %d for file %s timed out.\n",
 800                                         fsp->fnum, fsp->fsp_name ));
 801
 802                                 brl_lock_cancel(br_lck,
 803                                         blr->lock_pid,
 804                                         procid_self(),
 805                                         blr->offset,
 806                                         blr->count,
 807                                         blr->lock_flav);
 808                                 TALLOC_FREE(br_lck);
 809                         }
 810
 811                         blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
 812                         DLIST_REMOVE(blocking_lock_queue, blr);
 813                         free_blocking_lock_record(blr);
 814                         recalc_timeout = True;
 815                 }
 816         }
 817
 818         if (recalc_timeout) {
 819                 recalc_brl_timeout();
 820         }
 821 }
 822
 823 /****************************************************************************
 824  Handle a cancel message. Lock already moved onto the cancel queue.
 825 *****************************************************************************/
 826
 827 #define MSG_BLOCKING_LOCK_CANCEL_SIZE (sizeof(blocking_lock_record *) + sizeof(NTSTATUS))
 828
 829 static void process_blocking_lock_cancel_message(struct messaging_context *ctx,
 830                                                  void *private_data,
 831                                                  uint32_t msg_type,
 832                                                  struct server_id server_id,
 833                                                  DATA_BLOB *data)
 834 {
 835         NTSTATUS err;
 836         const char *msg = (const char *)data->data;
 837         blocking_lock_record *blr;
 838
 839         if (data->data == NULL) {
 840                 smb_panic("process_blocking_lock_cancel_message: null msg");
 841         }
 842
 843         if (data->length != MSG_BLOCKING_LOCK_CANCEL_SIZE) {
 844                 DEBUG(0, ("process_blocking_lock_cancel_message: "
 845                           "Got invalid msg len %d\n", (int)data->length));
 846                 smb_panic("process_blocking_lock_cancel_message: bad msg");
 847         }
 848
 849         memcpy(&blr, msg, sizeof(blr));
 850         memcpy(&err, &msg[sizeof(blr)], sizeof(NTSTATUS));
 851
 852         DEBUG(10,("process_blocking_lock_cancel_message: returning error %s\n",
 853                 nt_errstr(err) ));
 854
 855         blocking_lock_reply_error(blr, err);
 856         DLIST_REMOVE(blocking_lock_cancelled_queue, blr);
 857         free_blocking_lock_record(blr);
 858 }
 859
 860 /****************************************************************************
 861  Send ourselves a blocking lock cancelled message. Handled asynchronously above.
 862 *****************************************************************************/
 863
 864 bool blocking_lock_cancel(files_struct *fsp,
 865                         uint32 lock_pid,
 866                         SMB_BIG_UINT offset,
 867                         SMB_BIG_UINT count,
 868                         enum brl_flavour lock_flav,
 869                         unsigned char locktype,
 870                         NTSTATUS err)
 871 {
 872         static bool initialized;
 873         char msg[MSG_BLOCKING_LOCK_CANCEL_SIZE];
 874         blocking_lock_record *blr;
 875
 876         if (!initialized) {
 877                 /* Register our message. */
 878                 messaging_register(smbd_messaging_context(), NULL,
 879                                    MSG_SMB_BLOCKING_LOCK_CANCEL,
 880                                    process_blocking_lock_cancel_message);
 881
 882                 initialized = True;
 883         }
 884
 885         for (blr = blocking_lock_queue; blr; blr = blr->next) {
 886                 if (fsp == blr->fsp &&
 887                                 lock_pid == blr->lock_pid &&
 888                                 offset == blr->offset &&
 889                                 count == blr->count &&
 890                                 lock_flav == blr->lock_flav) {
 891                         break;
 892                 }
 893         }
 894
 895         if (!blr) {
 896                 return False;
 897         }
 898
 899         /* Check the flags are right. */
 900         if (blr->com_type == SMBlockingX &&
 901                 (locktype & LOCKING_ANDX_LARGE_FILES) !=
 902                         (CVAL(blr->inbuf,smb_vwv3) & LOCKING_ANDX_LARGE_FILES)) {
 903                 return False;
 904         }
 905
 906         /* Move to cancelled queue. */
 907         DLIST_REMOVE(blocking_lock_queue, blr);
 908         DLIST_ADD(blocking_lock_cancelled_queue, blr);
 909
 910         /* Create the message. */
 911         memcpy(msg, &blr, sizeof(blr));
 912         memcpy(&msg[sizeof(blr)], &err, sizeof(NTSTATUS));
 913
 914         messaging_send_buf(smbd_messaging_context(), procid_self(),
 915                            MSG_SMB_BLOCKING_LOCK_CANCEL,
 916                            (uint8 *)&msg, sizeof(msg));
 917
 918         return True;
 919 }