source/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 extern int max_send;
  25
  26 /****************************************************************************
  27  This is the structure to queue to implement blocking locks.
  28  notify. It consists of the requesting SMB and the expiry time.
  29 *****************************************************************************/
  30
  31 typedef struct _blocking_lock_record {
  32         struct _blocking_lock_record *next;
  33         struct _blocking_lock_record *prev;
  34         int com_type;
  35         files_struct *fsp;
  36         struct timeval expire_time;
  37         int lock_num;
  38         SMB_BIG_UINT offset;
  39         SMB_BIG_UINT count;
  40         uint32 lock_pid;
  41         uint32 blocking_pid; /* PID that blocks us. */
  42         enum brl_flavour lock_flav;
  43         enum brl_type lock_type;
  44         char *inbuf;
  45         int length;
  46 } blocking_lock_record;
  47
  48 /* dlink list we store pending lock records on. */
  49 static blocking_lock_record *blocking_lock_queue;
  50
  51 /* dlink list we move cancelled lock records onto. */
  52 static blocking_lock_record *blocking_lock_cancelled_queue;
  53
  54 /* The event that makes us process our blocking lock queue */
  55 static struct timed_event *brl_timeout;
  56
  57 /****************************************************************************
  58  Destructor for the above structure.
  59 ****************************************************************************/
  60
  61 static void free_blocking_lock_record(blocking_lock_record *blr)
  62 {
  63         SAFE_FREE(blr->inbuf);
  64         SAFE_FREE(blr);
  65 }
  66
  67 /****************************************************************************
  68  Determine if this is a secondary element of a chained SMB.
  69   **************************************************************************/
  70
  71 static BOOL in_chained_smb(void)
  72 {
  73         return (chain_size != 0);
  74 }
  75
  76 static void received_unlock_msg(struct messaging_context *msg,
  77                                 void *private_data,
  78                                 uint32_t msg_type,
  79                                 struct server_id server_id,
  80                                 DATA_BLOB *data);
  81 static void process_blocking_lock_queue(void);
  82
  83 static void brl_timeout_fn(struct event_context *event_ctx,
  84                            struct timed_event *te,
  85                            const struct timeval *now,
  86                            void *private_data)
  87 {
  88         SMB_ASSERT(brl_timeout == te);
  89         TALLOC_FREE(brl_timeout);
  90
  91         change_to_root_user();  /* TODO: Possibly run all timed events as
  92                                  * root */
  93
  94         process_blocking_lock_queue();
  95 }
  96
  97 /****************************************************************************
  98  After a change to blocking_lock_queue, recalculate the timed_event for the
  99  next processing.
 100 ****************************************************************************/
 101
 102 static BOOL recalc_brl_timeout(void)
 103 {
 104         blocking_lock_record *brl;
 105         struct timeval next_timeout;
 106
 107         TALLOC_FREE(brl_timeout);
 108
 109         next_timeout = timeval_zero();
 110
 111         for (brl = blocking_lock_queue; brl; brl = brl->next) {
 112                 if (timeval_is_zero(&brl->expire_time)) {
 113                         /*
 114                          * If we're blocked on pid 0xFFFFFFFF this is
 115                          * a POSIX lock, so calculate a timeout of
 116                          * 10 seconds into the future.
 117                          */
 118                         if (brl->blocking_pid == 0xFFFFFFFF) {
 119                                 struct timeval psx_to = timeval_current_ofs(10, 0);
 120                                 next_timeout = timeval_min(&next_timeout, &psx_to);
 121                         }
 122
 123                         continue;
 124                 }
 125
 126                 if (timeval_is_zero(&next_timeout)) {
 127                         next_timeout = brl->expire_time;
 128                 }
 129                 else {
 130                         next_timeout = timeval_min(&next_timeout,
 131                                                    &brl->expire_time);
 132                 }
 133         }
 134
 135         if (timeval_is_zero(&next_timeout)) {
 136                 return True;
 137         }
 138
 139         if (!(brl_timeout = event_add_timed(smbd_event_context(), NULL,
 140                                             next_timeout, "brl_timeout",
 141                                             brl_timeout_fn, NULL))) {
 142                 return False;
 143         }
 144
 145         return True;
 146 }
 147
 148
 149 /****************************************************************************
 150  Function to push a blocking lock request onto the lock queue.
 151 ****************************************************************************/
 152
 153 BOOL push_blocking_lock_request( struct byte_range_lock *br_lck,
 154                 char *inbuf, int length,
 155                 files_struct *fsp,
 156                 int lock_timeout,
 157                 int lock_num,
 158                 uint32 lock_pid,
 159                 enum brl_type lock_type,
 160                 enum brl_flavour lock_flav,
 161                 SMB_BIG_UINT offset,
 162                 SMB_BIG_UINT count,
 163                 uint32 blocking_pid)
 164 {
 165         static BOOL set_lock_msg;
 166         blocking_lock_record *blr;
 167         NTSTATUS status;
 168
 169         if(in_chained_smb() ) {
 170                 DEBUG(0,("push_blocking_lock_request: cannot queue a chained request (currently).\n"));
 171                 return False;
 172         }
 173
 174         /*
 175          * Now queue an entry on the blocking lock queue. We setup
 176          * the expiration time here.
 177          */
 178
 179         if((blr = SMB_MALLOC_P(blocking_lock_record)) == NULL) {
 180                 DEBUG(0,("push_blocking_lock_request: Malloc fail !\n" ));
 181                 return False;
 182         }
 183
 184         blr->next = NULL;
 185         blr->prev = NULL;
 186
 187         if((blr->inbuf = (char *)SMB_MALLOC(length)) == NULL) {
 188                 DEBUG(0,("push_blocking_lock_request: Malloc fail (2)!\n" ));
 189                 SAFE_FREE(blr);
 190                 return False;
 191         }
 192
 193         blr->com_type = CVAL(inbuf,smb_com);
 194         blr->fsp = fsp;
 195         if (lock_timeout == -1) {
 196                 blr->expire_time.tv_sec = 0;
 197                 blr->expire_time.tv_usec = 0; /* Never expire. */
 198         } else {
 199                 blr->expire_time = timeval_current_ofs(lock_timeout/1000,
 200                                         (lock_timeout % 1000) * 1000);
 201         }
 202         blr->lock_num = lock_num;
 203         blr->lock_pid = lock_pid;
 204         blr->blocking_pid = blocking_pid;
 205         blr->lock_flav = lock_flav;
 206         blr->lock_type = lock_type;
 207         blr->offset = offset;
 208         blr->count = count;
 209         memcpy(blr->inbuf, inbuf, length);
 210         blr->length = length;
 211
 212         /* Add a pending lock record for this. */
 213         status = brl_lock(smbd_messaging_context(), br_lck,
 214                         lock_pid,
 215                         procid_self(),
 216                         offset,
 217                         count,
 218                         lock_type == READ_LOCK ? PENDING_READ_LOCK : PENDING_WRITE_LOCK,
 219                         blr->lock_flav,
 220                         lock_timeout ? True : False, /* blocking_lock. */
 221                         NULL);
 222
 223         if (!NT_STATUS_IS_OK(status)) {
 224                 DEBUG(0,("push_blocking_lock_request: failed to add PENDING_LOCK record.\n"));
 225                 DLIST_REMOVE(blocking_lock_queue, blr);
 226                 free_blocking_lock_record(blr);
 227                 return False;
 228         }
 229
 230         DLIST_ADD_END(blocking_lock_queue, blr, blocking_lock_record *);
 231         recalc_brl_timeout();
 232
 233         /* Ensure we'll receive messages when this is unlocked. */
 234         if (!set_lock_msg) {
 235                 messaging_register(smbd_messaging_context(), NULL,
 236                                    MSG_SMB_UNLOCK, received_unlock_msg);
 237                 set_lock_msg = True;
 238         }
 239
 240         DEBUG(3,("push_blocking_lock_request: lock request length=%d blocked with "
 241                 "expiry time (%u sec. %u usec) (+%d msec) for fnum = %d, name = %s\n",
 242                 length, (unsigned int)blr->expire_time.tv_sec,
 243                 (unsigned int)blr->expire_time.tv_usec, lock_timeout,
 244                 blr->fsp->fnum, blr->fsp->fsp_name ));
 245
 246         /* Push the MID of this packet on the signing queue. */
 247         srv_defer_sign_response(SVAL(inbuf,smb_mid));
 248
 249         return True;
 250 }
 251
 252 /****************************************************************************
 253  Return a smd with a given size.
 254 *****************************************************************************/
 255
 256 static void send_blocking_reply(char *outbuf, int outsize, const char *inbuf)
 257 {
 258         if(outsize > 4) {
 259                 smb_setlen(inbuf, outbuf,outsize - 4);
 260         }
 261
 262         if (!send_smb(smbd_server_fd(),outbuf)) {
 263                 exit_server_cleanly("send_blocking_reply: send_smb failed.");
 264         }
 265 }
 266
 267 /****************************************************************************
 268  Return a lockingX success SMB.
 269 *****************************************************************************/
 270
 271 static void reply_lockingX_success(blocking_lock_record *blr)
 272 {
 273         char *outbuf = get_OutBuffer();
 274         int bufsize = BUFFER_SIZE;
 275         char *inbuf = blr->inbuf;
 276         int outsize = 0;
 277
 278         construct_reply_common(inbuf, outbuf);
 279         set_message(inbuf,outbuf,2,0,True);
 280
 281         /*
 282          * As this message is a lockingX call we must handle
 283          * any following chained message correctly.
 284          * This is normally handled in construct_reply(),
 285          * but as that calls switch_message, we can't use
 286          * that here and must set up the chain info manually.
 287          */
 288
 289         outsize = chain_reply(inbuf,outbuf,blr->length,bufsize);
 290
 291         outsize += chain_size;
 292
 293         send_blocking_reply(outbuf,outsize,inbuf);
 294 }
 295
 296 /****************************************************************************
 297  Return a generic lock fail error blocking call.
 298 *****************************************************************************/
 299
 300 static void generic_blocking_lock_error(blocking_lock_record *blr, NTSTATUS status)
 301 {
 302         char *outbuf = get_OutBuffer();
 303         char *inbuf = blr->inbuf;
 304         construct_reply_common(inbuf, outbuf);
 305
 306         /* whenever a timeout is given w2k maps LOCK_NOT_GRANTED to
 307            FILE_LOCK_CONFLICT! (tridge) */
 308         if (NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) {
 309                 status = NT_STATUS_FILE_LOCK_CONFLICT;
 310         }
 311
 312         if (NT_STATUS_EQUAL(status, NT_STATUS_FILE_LOCK_CONFLICT)) {
 313                 /* Store the last lock error. */
 314                 files_struct *fsp = blr->fsp;
 315
 316                 fsp->last_lock_failure.context.smbpid = blr->lock_pid;
 317                 fsp->last_lock_failure.context.tid = fsp->conn->cnum;
 318                 fsp->last_lock_failure.context.pid = procid_self();
 319                 fsp->last_lock_failure.start = blr->offset;
 320                 fsp->last_lock_failure.size = blr->count;
 321                 fsp->last_lock_failure.fnum = fsp->fnum;
 322                 fsp->last_lock_failure.lock_type = READ_LOCK; /* Don't care. */
 323                 fsp->last_lock_failure.lock_flav = blr->lock_flav;
 324         }
 325
 326         ERROR_NT(status);
 327         if (!send_smb(smbd_server_fd(),outbuf)) {
 328                 exit_server_cleanly("generic_blocking_lock_error: send_smb failed.");
 329         }
 330 }
 331
 332 /****************************************************************************
 333  Return a lock fail error for a lockingX call. Undo all the locks we have
 334  obtained first.
 335 *****************************************************************************/
 336
 337 static void reply_lockingX_error(blocking_lock_record *blr, NTSTATUS status)
 338 {
 339         char *inbuf = blr->inbuf;
 340         files_struct *fsp = blr->fsp;
 341         uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
 342         SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT) 0;
 343         uint32 lock_pid;
 344         unsigned char locktype = CVAL(inbuf,smb_vwv3);
 345         BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
 346         char *data;
 347         int i;
 348
 349         data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
 350
 351         /*
 352          * Data now points at the beginning of the list
 353          * of smb_lkrng structs.
 354          */
 355
 356         /*
 357          * Ensure we don't do a remove on the lock that just failed,
 358          * as under POSIX rules, if we have a lock already there, we
 359          * will delete it (and we shouldn't) .....
 360          */
 361
 362         for(i = blr->lock_num - 1; i >= 0; i--) {
 363                 BOOL err;
 364
 365                 lock_pid = get_lock_pid( data, i, large_file_format);
 366                 count = get_lock_count( data, i, large_file_format);
 367                 offset = get_lock_offset( data, i, large_file_format, &err);
 368
 369                 /*
 370                  * We know err cannot be set as if it was the lock
 371                  * request would never have been queued. JRA.
 372                  */
 373
 374                 do_unlock(smbd_messaging_context(),
 375                         fsp,
 376                         lock_pid,
 377                         count,
 378                         offset,
 379                         WINDOWS_LOCK);
 380         }
 381
 382         generic_blocking_lock_error(blr, status);
 383 }
 384
 385 /****************************************************************************
 386  Return a lock fail error.
 387 *****************************************************************************/
 388
 389 static void blocking_lock_reply_error(blocking_lock_record *blr, NTSTATUS status)
 390 {
 391         switch(blr->com_type) {
 392         case SMBlockingX:
 393                 reply_lockingX_error(blr, status);
 394                 break;
 395         case SMBtrans2:
 396         case SMBtranss2:
 397                 {
 398                         char *outbuf = get_OutBuffer();
 399                         char *inbuf = blr->inbuf;
 400                         construct_reply_common(inbuf, outbuf);
 401                         /* construct_reply_common has done us the favor to pre-fill the
 402                          * command field with SMBtranss2 which is wrong :-)
 403                          */
 404                         SCVAL(outbuf,smb_com,SMBtrans2);
 405                         ERROR_NT(status);
 406                         if (!send_smb(smbd_server_fd(),outbuf)) {
 407                                 exit_server_cleanly("blocking_lock_reply_error: send_smb failed.");
 408                         }
 409                         break;
 410                 }
 411         default:
 412                 DEBUG(0,("blocking_lock_reply_error: PANIC - unknown type on blocking lock queue - exiting.!\n"));
 413                 exit_server("PANIC - unknown type on blocking lock queue");
 414         }
 415 }
 416
 417 /****************************************************************************
 418  Attempt to finish off getting all pending blocking locks for a lockingX call.
 419  Returns True if we want to be removed from the list.
 420 *****************************************************************************/
 421
 422 static BOOL process_lockingX(blocking_lock_record *blr)
 423 {
 424         char *inbuf = blr->inbuf;
 425         unsigned char locktype = CVAL(inbuf,smb_vwv3);
 426         files_struct *fsp = blr->fsp;
 427         uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
 428         uint16 num_locks = SVAL(inbuf,smb_vwv7);
 429         SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT)0;
 430         uint32 lock_pid;
 431         BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
 432         char *data;
 433         NTSTATUS status = NT_STATUS_OK;
 434
 435         data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
 436
 437         /*
 438          * Data now points at the beginning of the list
 439          * of smb_lkrng structs.
 440          */
 441
 442         for(; blr->lock_num < num_locks; blr->lock_num++) {
 443                 struct byte_range_lock *br_lck = NULL;
 444                 BOOL err;
 445
 446                 lock_pid = get_lock_pid( data, blr->lock_num, large_file_format);
 447                 count = get_lock_count( data, blr->lock_num, large_file_format);
 448                 offset = get_lock_offset( data, blr->lock_num, large_file_format, &err);
 449
 450                 /*
 451                  * We know err cannot be set as if it was the lock
 452                  * request would never have been queued. JRA.
 453                  */
 454                 errno = 0;
 455                 br_lck = do_lock(smbd_messaging_context(),
 456                                 fsp,
 457                                 lock_pid,
 458                                 count,
 459                                 offset,
 460                                 ((locktype & LOCKING_ANDX_SHARED_LOCK) ?
 461                                         READ_LOCK : WRITE_LOCK),
 462                                 WINDOWS_LOCK,
 463                                 True,
 464                                 &status,
 465                                 &blr->blocking_pid);
 466
 467                 TALLOC_FREE(br_lck);
 468
 469                 if (NT_STATUS_IS_ERR(status)) {
 470                         break;
 471                 }
 472         }
 473
 474         if(blr->lock_num == num_locks) {
 475                 /*
 476                  * Success - we got all the locks.
 477                  */
 478
 479                 DEBUG(3,("process_lockingX file = %s, fnum=%d type=%d num_locks=%d\n",
 480                          fsp->fsp_name, fsp->fnum, (unsigned int)locktype, num_locks) );
 481
 482                 reply_lockingX_success(blr);
 483                 return True;
 484         } else if (!NT_STATUS_EQUAL(status,NT_STATUS_LOCK_NOT_GRANTED) &&
 485                         !NT_STATUS_EQUAL(status,NT_STATUS_FILE_LOCK_CONFLICT)) {
 486                         /*
 487                          * We have other than a "can't get lock"
 488                          * error. Free any locks we had and return an error.
 489                          * Return True so we get dequeued.
 490                          */
 491
 492                 blocking_lock_reply_error(blr, status);
 493                 return True;
 494         }
 495
 496         /*
 497          * Still can't get all the locks - keep waiting.
 498          */
 499
 500         DEBUG(10,("process_lockingX: only got %d locks of %d needed for file %s, fnum = %d. \
 501 Waiting....\n",
 502                   blr->lock_num, num_locks, fsp->fsp_name, fsp->fnum));
 503
 504         return False;
 505 }
 506
 507 /****************************************************************************
 508  Attempt to get the posix lock request from a SMBtrans2 call.
 509  Returns True if we want to be removed from the list.
 510 *****************************************************************************/
 511
 512 static BOOL process_trans2(blocking_lock_record *blr)
 513 {
 514         char *inbuf = blr->inbuf;
 515         char *outbuf;
 516         char params[2];
 517         NTSTATUS status;
 518         struct byte_range_lock *br_lck = do_lock(smbd_messaging_context(),
 519                                                 blr->fsp,
 520                                                 blr->lock_pid,
 521                                                 blr->count,
 522                                                 blr->offset,
 523                                                 blr->lock_type,
 524                                                 blr->lock_flav,
 525                                                 True,
 526                                                 &status,
 527                                                 &blr->blocking_pid);
 528         TALLOC_FREE(br_lck);
 529
 530         if (!NT_STATUS_IS_OK(status)) {
 531                 if (ERROR_WAS_LOCK_DENIED(status)) {
 532                         /* Still can't get the lock, just keep waiting. */
 533                         return False;
 534                 }
 535                 /*
 536                  * We have other than a "can't get lock"
 537                  * error. Send an error and return True so we get dequeued.
 538                  */
 539                 blocking_lock_reply_error(blr, status);
 540                 return True;
 541         }
 542
 543         /* We finally got the lock, return success. */
 544         outbuf = get_OutBuffer();
 545         construct_reply_common(inbuf, outbuf);
 546         SCVAL(outbuf,smb_com,SMBtrans2);
 547         SSVAL(params,0,0);
 548         /* Fake up max_data_bytes here - we know it fits. */
 549         send_trans2_replies(inbuf, outbuf, max_send, params, 2, NULL, 0, 0xffff);
 550         return True;
 551 }
 552
 553
 554 /****************************************************************************
 555  Process a blocking lock SMB.
 556  Returns True if we want to be removed from the list.
 557 *****************************************************************************/
 558
 559 static BOOL blocking_lock_record_process(blocking_lock_record *blr)
 560 {
 561         switch(blr->com_type) {
 562                 case SMBlockingX:
 563                         return process_lockingX(blr);
 564                 case SMBtrans2:
 565                 case SMBtranss2:
 566                         return process_trans2(blr);
 567                 default:
 568                         DEBUG(0,("blocking_lock_record_process: PANIC - unknown type on blocking lock queue - exiting.!\n"));
 569                         exit_server("PANIC - unknown type on blocking lock queue");
 570         }
 571         return False; /* Keep compiler happy. */
 572 }
 573
 574 /****************************************************************************
 575  Cancel entries by fnum from the blocking lock pending queue.
 576 *****************************************************************************/
 577
 578 void cancel_pending_lock_requests_by_fid(files_struct *fsp, struct byte_range_lock *br_lck)
 579 {
 580         blocking_lock_record *blr, *next = NULL;
 581
 582         for(blr = blocking_lock_queue; blr; blr = next) {
 583                 next = blr->next;
 584                 if(blr->fsp->fnum == fsp->fnum) {
 585                         unsigned char locktype = 0;
 586
 587                         if (blr->com_type == SMBlockingX) {
 588                                 locktype = CVAL(blr->inbuf,smb_vwv3);
 589                         }
 590
 591                         if (br_lck) {
 592                                 DEBUG(10,("remove_pending_lock_requests_by_fid - removing request type %d for \
 593 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
 594
 595                                 brl_lock_cancel(br_lck,
 596                                         blr->lock_pid,
 597                                         procid_self(),
 598                                         blr->offset,
 599                                         blr->count,
 600                                         blr->lock_flav);
 601
 602                                 blocking_lock_cancel(fsp,
 603                                         blr->lock_pid,
 604                                         blr->offset,
 605                                         blr->count,
 606                                         blr->lock_flav,
 607                                         locktype,
 608                                         NT_STATUS_RANGE_NOT_LOCKED);
 609                         }
 610                 }
 611         }
 612 }
 613
 614 /****************************************************************************
 615  Delete entries by mid from the blocking lock pending queue. Always send reply.
 616 *****************************************************************************/
 617
 618 void remove_pending_lock_requests_by_mid(int mid)
 619 {
 620         blocking_lock_record *blr, *next = NULL;
 621
 622         for(blr = blocking_lock_queue; blr; blr = next) {
 623                 next = blr->next;
 624                 if(SVAL(blr->inbuf,smb_mid) == mid) {
 625                         files_struct *fsp = blr->fsp;
 626                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
 627
 628                         if (br_lck) {
 629                                 DEBUG(10,("remove_pending_lock_requests_by_mid - removing request type %d for \
 630 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
 631
 632                                 brl_lock_cancel(br_lck,
 633                                         blr->lock_pid,
 634                                         procid_self(),
 635                                         blr->offset,
 636                                         blr->count,
 637                                         blr->lock_flav);
 638                                 TALLOC_FREE(br_lck);
 639                         }
 640
 641                         blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
 642                         DLIST_REMOVE(blocking_lock_queue, blr);
 643                         free_blocking_lock_record(blr);
 644                 }
 645         }
 646 }
 647
 648 /****************************************************************************
 649  Is this mid a blocking lock request on the queue ?
 650 *****************************************************************************/
 651
 652 BOOL blocking_lock_was_deferred(int mid)
 653 {
 654         blocking_lock_record *blr, *next = NULL;
 655
 656         for(blr = blocking_lock_queue; blr; blr = next) {
 657                 next = blr->next;
 658                 if(SVAL(blr->inbuf,smb_mid) == mid) {
 659                         return True;
 660                 }
 661         }
 662         return False;
 663 }
 664
 665 /****************************************************************************
 666   Set a flag as an unlock request affects one of our pending locks.
 667 *****************************************************************************/
 668
 669 static void received_unlock_msg(struct messaging_context *msg,
 670                                 void *private_data,
 671                                 uint32_t msg_type,
 672                                 struct server_id server_id,
 673                                 DATA_BLOB *data)
 674 {
 675         DEBUG(10,("received_unlock_msg\n"));
 676         process_blocking_lock_queue();
 677 }
 678
 679 /****************************************************************************
 680  Process the blocking lock queue. Note that this is only called as root.
 681 *****************************************************************************/
 682
 683 static void process_blocking_lock_queue(void)
 684 {
 685         struct timeval tv_curr = timeval_current();
 686         blocking_lock_record *blr, *next = NULL;
 687         BOOL recalc_timeout = False;
 688
 689         /*
 690          * Go through the queue and see if we can get any of the locks.
 691          */
 692
 693         for (blr = blocking_lock_queue; blr; blr = next) {
 694                 connection_struct *conn = NULL;
 695                 uint16 vuid;
 696                 files_struct *fsp = NULL;
 697
 698                 next = blr->next;
 699
 700                 /*
 701                  * Ensure we don't have any old chain_fsp values
 702                  * sitting around....
 703                  */
 704                 chain_size = 0;
 705                 file_chain_reset();
 706                 fsp = blr->fsp;
 707
 708                 conn = conn_find(SVAL(blr->inbuf,smb_tid));
 709                 vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID :
 710                                 SVAL(blr->inbuf,smb_uid);
 711
 712                 DEBUG(5,("process_blocking_lock_queue: examining pending lock fnum = %d for file %s\n",
 713                         fsp->fnum, fsp->fsp_name ));
 714
 715                 if (!timeval_is_zero(&blr->expire_time) && timeval_compare(&blr->expire_time, &tv_curr) <= 0) {
 716                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
 717
 718                         /*
 719                          * Lock expired - throw away all previously
 720                          * obtained locks and return lock error.
 721                          */
 722
 723                         if (br_lck) {
 724                                 DEBUG(5,("process_blocking_lock_queue: pending lock fnum = %d for file %s timed out.\n",
 725                                         fsp->fnum, fsp->fsp_name ));
 726
 727                                 brl_lock_cancel(br_lck,
 728                                         blr->lock_pid,
 729                                         procid_self(),
 730                                         blr->offset,
 731                                         blr->count,
 732                                         blr->lock_flav);
 733                                 TALLOC_FREE(br_lck);
 734                         }
 735
 736                         blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
 737                         DLIST_REMOVE(blocking_lock_queue, blr);
 738                         free_blocking_lock_record(blr);
 739                         recalc_timeout = True;
 740                         continue;
 741                 }
 742
 743                 if(!change_to_user(conn,vuid)) {
 744                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
 745
 746                         /*
 747                          * Remove the entry and return an error to the client.
 748                          */
 749
 750                         if (br_lck) {
 751                                 brl_lock_cancel(br_lck,
 752                                         blr->lock_pid,
 753                                         procid_self(),
 754                                         blr->offset,
 755                                         blr->count,
 756                                         blr->lock_flav);
 757                                 TALLOC_FREE(br_lck);
 758                         }
 759
 760                         DEBUG(0,("process_blocking_lock_queue: Unable to become user vuid=%d.\n",
 761                                 vuid ));
 762                         blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
 763                         DLIST_REMOVE(blocking_lock_queue, blr);
 764                         free_blocking_lock_record(blr);
 765                         recalc_timeout = True;
 766                         continue;
 767                 }
 768
 769                 if(!set_current_service(conn,SVAL(blr->inbuf,smb_flg),True)) {
 770                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
 771
 772                         /*
 773                          * Remove the entry and return an error to the client.
 774                          */
 775
 776                         if (br_lck) {
 777                                 brl_lock_cancel(br_lck,
 778                                         blr->lock_pid,
 779                                         procid_self(),
 780                                         blr->offset,
 781                                         blr->count,
 782                                         blr->lock_flav);
 783                                 TALLOC_FREE(br_lck);
 784                         }
 785
 786                         DEBUG(0,("process_blocking_lock_queue: Unable to become service Error was %s.\n", strerror(errno) ));
 787                         blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
 788                         DLIST_REMOVE(blocking_lock_queue, blr);
 789                         free_blocking_lock_record(blr);
 790                         recalc_timeout = True;
 791                         change_to_root_user();
 792                         continue;
 793                 }
 794
 795                 /*
 796                  * Go through the remaining locks and try and obtain them.
 797                  * The call returns True if all locks were obtained successfully
 798                  * and False if we still need to wait.
 799                  */
 800
 801                 if(blocking_lock_record_process(blr)) {
 802                         struct byte_range_lock *br_lck = brl_get_locks(NULL, fsp);
 803
 804                         if (br_lck) {
 805                                 brl_lock_cancel(br_lck,
 806                                         blr->lock_pid,
 807                                         procid_self(),
 808                                         blr->offset,
 809                                         blr->count,
 810                                         blr->lock_flav);
 811                                 TALLOC_FREE(br_lck);
 812                         }
 813
 814                         DLIST_REMOVE(blocking_lock_queue, blr);
 815                         free_blocking_lock_record(blr);
 816                         recalc_timeout = True;
 817                 }
 818                 change_to_root_user();
 819         }
 820
 821         if (recalc_timeout) {
 822                 recalc_brl_timeout();
 823         }
 824 }
 825
 826 /****************************************************************************
 827  Handle a cancel message. Lock already moved onto the cancel queue.
 828 *****************************************************************************/
 829
 830 #define MSG_BLOCKING_LOCK_CANCEL_SIZE (sizeof(blocking_lock_record *) + sizeof(NTSTATUS))
 831
 832 static void process_blocking_lock_cancel_message(struct messaging_context *ctx,
 833                                                  void *private_data,
 834                                                  uint32_t msg_type,
 835                                                  struct server_id server_id,
 836                                                  DATA_BLOB *data)
 837 {
 838         NTSTATUS err;
 839         const char *msg = (const char *)data->data;
 840         blocking_lock_record *blr;
 841
 842         if (data->data == NULL) {
 843                 smb_panic("process_blocking_lock_cancel_message: null msg");
 844         }
 845
 846         if (data->length != MSG_BLOCKING_LOCK_CANCEL_SIZE) {
 847                 DEBUG(0, ("process_blocking_lock_cancel_message: "
 848                           "Got invalid msg len %d\n", (int)data->length));
 849                 smb_panic("process_blocking_lock_cancel_message: bad msg");
 850         }
 851
 852         memcpy(&blr, msg, sizeof(blr));
 853         memcpy(&err, &msg[sizeof(blr)], sizeof(NTSTATUS));
 854
 855         DEBUG(10,("process_blocking_lock_cancel_message: returning error %s\n",
 856                 nt_errstr(err) ));
 857
 858         blocking_lock_reply_error(blr, err);
 859         DLIST_REMOVE(blocking_lock_cancelled_queue, blr);
 860         free_blocking_lock_record(blr);
 861 }
 862
 863 /****************************************************************************
 864  Send ourselves a blocking lock cancelled message. Handled asynchronously above.
 865 *****************************************************************************/
 866
 867 BOOL blocking_lock_cancel(files_struct *fsp,
 868                         uint32 lock_pid,
 869                         SMB_BIG_UINT offset,
 870                         SMB_BIG_UINT count,
 871                         enum brl_flavour lock_flav,
 872                         unsigned char locktype,
 873                         NTSTATUS err)
 874 {
 875         static BOOL initialized;
 876         char msg[MSG_BLOCKING_LOCK_CANCEL_SIZE];
 877         blocking_lock_record *blr;
 878
 879         if (!initialized) {
 880                 /* Register our message. */
 881                 messaging_register(smbd_messaging_context(), NULL,
 882                                    MSG_SMB_BLOCKING_LOCK_CANCEL,
 883                                    process_blocking_lock_cancel_message);
 884
 885                 initialized = True;
 886         }
 887
 888         for (blr = blocking_lock_queue; blr; blr = blr->next) {
 889                 if (fsp == blr->fsp &&
 890                                 lock_pid == blr->lock_pid &&
 891                                 offset == blr->offset &&
 892                                 count == blr->count &&
 893                                 lock_flav == blr->lock_flav) {
 894                         break;
 895                 }
 896         }
 897
 898         if (!blr) {
 899                 return False;
 900         }
 901
 902         /* Check the flags are right. */
 903         if (blr->com_type == SMBlockingX &&
 904                 (locktype & LOCKING_ANDX_LARGE_FILES) !=
 905                         (CVAL(blr->inbuf,smb_vwv3) & LOCKING_ANDX_LARGE_FILES)) {
 906                 return False;
 907         }
 908
 909         /* Move to cancelled queue. */
 910         DLIST_REMOVE(blocking_lock_queue, blr);
 911         DLIST_ADD(blocking_lock_cancelled_queue, blr);
 912
 913         /* Create the message. */
 914         memcpy(msg, &blr, sizeof(blr));
 915         memcpy(&msg[sizeof(blr)], &err, sizeof(NTSTATUS));
 916
 917         messaging_send_buf(smbd_messaging_context(), procid_self(),
 918                            MSG_SMB_BLOCKING_LOCK_CANCEL,
 919                            (uint8 *)&msg, sizeof(msg));
 920
 921         return True;
 922 }