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         uint64_t offset;
  37         uint64_t count;
  38         uint32_t lock_pid;
  39         uint32_t 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         bool encrypted;
  45 } blocking_lock_record;
  46
  47 /* dlink list we store pending lock records on. */
  48 static blocking_lock_record *blocking_lock_queue;
  49
  50 /* dlink list we move cancelled lock records onto. */
  51 static blocking_lock_record *blocking_lock_cancelled_queue;
  52
  53 /* The event that makes us process our blocking lock queue */
  54 static struct timed_event *brl_timeout;
  55
  56 /****************************************************************************
  57  Destructor for the above structure.
  58 ****************************************************************************/
  59
  60 static void free_blocking_lock_record(blocking_lock_record *blr)
  61 {
  62         SAFE_FREE(blr->inbuf);
  63         SAFE_FREE(blr);
  64 }
  65
  66 /****************************************************************************
  67  Determine if this is a secondary element of a chained SMB.
  68   **************************************************************************/
  69
  70 static bool in_chained_smb(void)
  71 {
  72         return (chain_size != 0);
  73 }
  74
  75 static void received_unlock_msg(struct messaging_context *msg,
  76                                 void *private_data,
  77                                 uint32_t msg_type,
  78                                 struct server_id server_id,
  79                                 DATA_BLOB *data);
  80 static void process_blocking_lock_queue(void);
  81
  82 static void brl_timeout_fn(struct event_context *event_ctx,
  83                            struct timed_event *te,
  84                            const struct timeval *now,
  85                            void *private_data)
  86 {
  87         SMB_ASSERT(brl_timeout == te);
  88         TALLOC_FREE(brl_timeout);
  89
  90         change_to_root_user();  /* TODO: Possibly run all timed events as
  91                                  * root */
  92
  93         process_blocking_lock_queue();
  94 }
  95
  96 /****************************************************************************
  97  After a change to blocking_lock_queue, recalculate the timed_event for the
  98  next processing.
  99 ****************************************************************************/
 100
 101 static bool recalc_brl_timeout(void)
 102 {
 103         blocking_lock_record *brl;
 104         struct timeval next_timeout;
 105
 106         TALLOC_FREE(brl_timeout);
 107
 108         next_timeout = timeval_zero();
 109
 110         for (brl = blocking_lock_queue; brl; brl = brl->next) {
 111                 if (timeval_is_zero(&brl->expire_time)) {
 112                         /*
 113                          * If we're blocked on pid 0xFFFFFFFF this is
 114                          * a POSIX lock, so calculate a timeout of
 115                          * 10 seconds into the future.
 116                          */
 117                         if (brl->blocking_pid == 0xFFFFFFFF) {
 118                                 struct timeval psx_to = timeval_current_ofs(10, 0);
 119                                 next_timeout = timeval_min(&next_timeout, &psx_to);
 120                         }
 121
 122                         continue;
 123                 }
 124
 125                 if (timeval_is_zero(&next_timeout)) {
 126                         next_timeout = brl->expire_time;
 127                 }
 128                 else {
 129                         next_timeout = timeval_min(&next_timeout,
 130                                                    &brl->expire_time);
 131                 }
 132         }
 133
 134         if (timeval_is_zero(&next_timeout)) {
 135                 return True;
 136         }
 137
 138         if (!(brl_timeout = event_add_timed(smbd_event_context(), NULL,
 139                                             next_timeout, "brl_timeout",
 140                                             brl_timeout_fn, NULL))) {
 141                 return False;
 142         }
 143
 144         return True;
 145 }
 146
 147
 148 /****************************************************************************
 149  Function to push a blocking lock request onto the lock queue.
 150 ****************************************************************************/
 151
 152 bool push_blocking_lock_request( struct byte_range_lock *br_lck,
 153                 const struct smb_request *req,
 154                 files_struct *fsp,
 155                 int lock_timeout,
 156                 int lock_num,
 157                 uint32_t lock_pid,
 158                 enum brl_type lock_type,
 159                 enum brl_flavour lock_flav,
 160                 uint64_t offset,
 161                 uint64_t count,
 162                 uint32_t blocking_pid)
 163 {
 164         static bool set_lock_msg;
 165         size_t length = smb_len(req->inbuf)+4;
 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(req->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, req->inbuf, length);
 210         blr->length = length;
 211         blr->encrypted = req->encrypted;
 212
 213         /* Add a pending lock record for this. */
 214         status = brl_lock(smbd_messaging_context(), br_lck,
 215                         lock_pid,
 216                         procid_self(),
 217                         offset,
 218                         count,
 219                         lock_type == READ_LOCK ? PENDING_READ_LOCK : PENDING_WRITE_LOCK,
 220                         blr->lock_flav,
 221                         lock_timeout ? True : False, /* blocking_lock. */
 222                         NULL);
 223
 224         if (!NT_STATUS_IS_OK(status)) {
 225                 DEBUG(0,("push_blocking_lock_request: failed to add PENDING_LOCK record.\n"));
 226                 DLIST_REMOVE(blocking_lock_queue, blr);
 227                 free_blocking_lock_record(blr);
 228                 return False;
 229         }
 230
 231         DLIST_ADD_END(blocking_lock_queue, blr, blocking_lock_record *);
 232         recalc_brl_timeout();
 233
 234         /* Ensure we'll receive messages when this is unlocked. */
 235         if (!set_lock_msg) {
 236                 messaging_register(smbd_messaging_context(), NULL,
 237                                    MSG_SMB_UNLOCK, received_unlock_msg);
 238                 set_lock_msg = True;
 239         }
 240
 241         DEBUG(3,("push_blocking_lock_request: lock request length=%u blocked with "
 242                 "expiry time (%u sec. %u usec) (+%d msec) for fnum = %d, name = %s\n",
 243                 (unsigned int)length, (unsigned int)blr->expire_time.tv_sec,
 244                 (unsigned int)blr->expire_time.tv_usec, lock_timeout,
 245                 blr->fsp->fnum, blr->fsp->fsp_name ));
 246
 247         /* Push the MID of this packet on the signing queue. */
 248         srv_defer_sign_response(SVAL(req->inbuf,smb_mid));
 249
 250         return True;
 251 }
 252
 253 /****************************************************************************
 254  Return a lockingX success SMB.
 255 *****************************************************************************/
 256
 257 static void reply_lockingX_success(blocking_lock_record *blr)
 258 {
 259         struct smb_request *req;
 260
 261         if (!(req = talloc(talloc_tos(), struct smb_request))) {
 262                 smb_panic("Could not allocate smb_request");
 263         }
 264
 265         init_smb_request(req, (uint8 *)blr->inbuf, 0, blr->encrypted);
 266         reply_outbuf(req, 2, 0);
 267
 268         /*
 269          * As this message is a lockingX call we must handle
 270          * any following chained message correctly.
 271          * This is normally handled in construct_reply(),
 272          * but as that calls switch_message, we can't use
 273          * that here and must set up the chain info manually.
 274          */
 275
 276         chain_reply(req);
 277
 278         if (!srv_send_smb(smbd_server_fd(),
 279                         (char *)req->outbuf,
 280                         IS_CONN_ENCRYPTED(blr->fsp->conn))) {
 281                 exit_server_cleanly("send_blocking_reply: srv_send_smb failed.");
 282         }
 283 }
 284
 285 /****************************************************************************
 286  Return a generic lock fail error blocking call.
 287 *****************************************************************************/
 288
 289 static void generic_blocking_lock_error(blocking_lock_record *blr, NTSTATUS status)
 290 {
 291         char outbuf[smb_size];
 292         char *inbuf = blr->inbuf;
 293
 294         construct_reply_common(inbuf, outbuf);
 295
 296         /* whenever a timeout is given w2k maps LOCK_NOT_GRANTED to
 297            FILE_LOCK_CONFLICT! (tridge) */
 298         if (NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) {
 299                 status = NT_STATUS_FILE_LOCK_CONFLICT;
 300         }
 301
 302         if (NT_STATUS_EQUAL(status, NT_STATUS_FILE_LOCK_CONFLICT)) {
 303                 /* Store the last lock error. */
 304                 files_struct *fsp = blr->fsp;
 305
 306                 if (fsp) {
 307                         fsp->last_lock_failure.context.smbpid = blr->lock_pid;
 308                         fsp->last_lock_failure.context.tid = fsp->conn->cnum;
 309                         fsp->last_lock_failure.context.pid = procid_self();
 310                         fsp->last_lock_failure.start = blr->offset;
 311                         fsp->last_lock_failure.size = blr->count;
 312                         fsp->last_lock_failure.fnum = fsp->fnum;
 313                         fsp->last_lock_failure.lock_type = READ_LOCK; /* Don't care. */
 314                         fsp->last_lock_failure.lock_flav = blr->lock_flav;
 315                 }
 316         }
 317
 318         ERROR_NT(status);
 319         if (!srv_send_smb(smbd_server_fd(),outbuf, blr->encrypted)) {
 320                 exit_server_cleanly("generic_blocking_lock_error: srv_send_smb failed.");
 321         }
 322 }
 323
 324 /****************************************************************************
 325  Return a lock fail error for a lockingX call. Undo all the locks we have
 326  obtained first.
 327 *****************************************************************************/
 328
 329 static void reply_lockingX_error(blocking_lock_record *blr, NTSTATUS status)
 330 {
 331         char *inbuf = blr->inbuf;
 332         files_struct *fsp = blr->fsp;
 333         uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
 334         uint64_t count = (uint64_t)0, offset = (uint64_t) 0;
 335         uint32 lock_pid;
 336         unsigned char locktype = CVAL(inbuf,smb_vwv3);
 337         bool large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
 338         char *data;
 339         int i;
 340
 341         data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
 342
 343         /*
 344          * Data now points at the beginning of the list
 345          * of smb_lkrng structs.
 346          */
 347
 348         /*
 349          * Ensure we don't do a remove on the lock that just failed,
 350          * as under POSIX rules, if we have a lock already there, we
 351          * will delete it (and we shouldn't) .....
 352          */
 353
 354         for(i = blr->lock_num - 1; i >= 0; i--) {
 355                 bool err;
 356
 357                 lock_pid = get_lock_pid( data, i, large_file_format);
 358                 count = get_lock_count( data, i, large_file_format);
 359                 offset = get_lock_offset( data, i, large_file_format, &err);
 360
 361                 /*
 362                  * We know err cannot be set as if it was the lock
 363                  * request would never have been queued. JRA.
 364                  */
 365
 366                 do_unlock(smbd_messaging_context(),
 367                         fsp,
 368                         lock_pid,
 369                         count,
 370                         offset,
 371                         WINDOWS_LOCK);
 372         }
 373
 374         generic_blocking_lock_error(blr, status);
 375 }
 376
 377 /****************************************************************************
 378  Return a lock fail error.
 379 *****************************************************************************/
 380
 381 static void blocking_lock_reply_error(blocking_lock_record *blr, NTSTATUS status)
 382 {
 383         switch(blr->com_type) {
 384         case SMBlockingX:
 385                 reply_lockingX_error(blr, status);
 386                 break;
 387         case SMBtrans2:
 388         case SMBtranss2:
 389                 {
 390                         char outbuf[smb_size];
 391                         char *inbuf = blr->inbuf;
 392                         construct_reply_common(inbuf, outbuf);
 393                         /* construct_reply_common has done us the favor to pre-fill the
 394                          * command field with SMBtranss2 which is wrong :-)
 395                          */
 396                         SCVAL(outbuf,smb_com,SMBtrans2);
 397                         ERROR_NT(status);
 398                         if (!srv_send_smb(smbd_server_fd(),
 399                                         outbuf,
 400                                         IS_CONN_ENCRYPTED(blr->fsp->conn))) {
 401                                 exit_server_cleanly("blocking_lock_reply_error: srv_send_smb failed.");
 402                         }
 403                         break;
 404                 }
 405         default:
 406                 DEBUG(0,("blocking_lock_reply_error: PANIC - unknown type on blocking lock queue - exiting.!\n"));
 407                 exit_server("PANIC - unknown type on blocking lock queue");
 408         }
 409 }
 410
 411 /****************************************************************************
 412  Attempt to finish off getting all pending blocking locks for a lockingX call.
 413  Returns True if we want to be removed from the list.
 414 *****************************************************************************/
 415
 416 static bool process_lockingX(blocking_lock_record *blr)
 417 {
 418         char *inbuf = blr->inbuf;
 419         unsigned char locktype = CVAL(inbuf,smb_vwv3);
 420         files_struct *fsp = blr->fsp;
 421         uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
 422         uint16 num_locks = SVAL(inbuf,smb_vwv7);
 423         uint64_t count = (uint64_t)0, offset = (uint64_t)0;
 424         uint32 lock_pid;
 425         bool large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
 426         char *data;
 427         NTSTATUS status = NT_STATUS_OK;
 428
 429         data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
 430
 431         /*
 432          * Data now points at the beginning of the list
 433          * of smb_lkrng structs.
 434          */
 435
 436         for(; blr->lock_num < num_locks; blr->lock_num++) {
 437                 struct byte_range_lock *br_lck = NULL;
 438                 bool err;
 439
 440                 lock_pid = get_lock_pid( data, blr->lock_num, large_file_format);
 441                 count = get_lock_count( data, blr->lock_num, large_file_format);
 442                 offset = get_lock_offset( data, blr->lock_num, large_file_format, &err);
 443
 444                 /*
 445                  * We know err cannot be set as if it was the lock
 446                  * request would never have been queued. JRA.
 447                  */
 448                 errno = 0;
 449                 br_lck = do_lock(smbd_messaging_context(),
 450                                 fsp,
 451                                 lock_pid,
 452                                 count,
 453                                 offset,
 454                                 ((locktype & LOCKING_ANDX_SHARED_LOCK) ?
 455                                         READ_LOCK : WRITE_LOCK),
 456                                 WINDOWS_LOCK,
 457                                 True,
 458                                 &status,
 459                                 &blr->blocking_pid);
 460
 461                 TALLOC_FREE(br_lck);
 462
 463                 if (NT_STATUS_IS_ERR(status)) {
 464                         break;
 465                 }
 466         }
 467
 468         if(blr->lock_num == num_locks) {
 469                 /*
 470                  * Success - we got all the locks.
 471                  */
 472
 473                 DEBUG(3,("process_lockingX file = %s, fnum=%d type=%d num_locks=%d\n",
 474                          fsp->fsp_name, fsp->fnum, (unsigned int)locktype, num_locks) );
 475
 476                 reply_lockingX_success(blr);
 477                 return True;
 478         } else if (!NT_STATUS_EQUAL(status,NT_STATUS_LOCK_NOT_GRANTED) &&
 479                         !NT_STATUS_EQUAL(status,NT_STATUS_FILE_LOCK_CONFLICT)) {
 480                         /*
 481                          * We have other than a "can't get lock"
 482                          * error. Free any locks we had and return an error.
 483                          * Return True so we get dequeued.
 484                          */
 485
 486                 blocking_lock_reply_error(blr, status);
 487                 return True;
 488         }
 489
 490         /*
 491          * Still can't get all the locks - keep waiting.
 492          */
 493
 494         DEBUG(10,("process_lockingX: only got %d locks of %d needed for file %s, fnum = %d. \
 495 Waiting....\n",
 496                   blr->lock_num, num_locks, fsp->fsp_name, fsp->fnum));
 497
 498         return False;
 499 }
 500
 501 /****************************************************************************
 502  Attempt to get the posix lock request from a SMBtrans2 call.
 503  Returns True if we want to be removed from the list.
 504 *****************************************************************************/
 505
 506 static bool process_trans2(blocking_lock_record *blr)
 507 {
 508         struct smb_request *req;
 509         char params[2];
 510         NTSTATUS status;
 511         struct byte_range_lock *br_lck = do_lock(smbd_messaging_context(),
 512                                                 blr->fsp,
 513                                                 blr->lock_pid,
 514                                                 blr->count,
 515                                                 blr->offset,
 516                                                 blr->lock_type,
 517                                                 blr->lock_flav,
 518                                                 True,
 519                                                 &status,
 520                                                 &blr->blocking_pid);
 521         TALLOC_FREE(br_lck);
 522
 523         if (!NT_STATUS_IS_OK(status)) {
 524                 if (ERROR_WAS_LOCK_DENIED(status)) {
 525                         /* Still can't get the lock, just keep waiting. */
 526                         return False;
 527                 }
 528                 /*
 529                  * We have other than a "can't get lock"
 530                  * error. Send an error and return True so we get dequeued.
 531                  */
 532                 blocking_lock_reply_error(blr, status);
 533                 return True;
 534         }
 535
 536         /* We finally got the lock, return success. */
 537
 538         if (!(req = talloc(talloc_tos(), struct smb_request))) {
 539                 blocking_lock_reply_error(blr, NT_STATUS_NO_MEMORY);
 540                 return True;
 541         }
 542
 543         init_smb_request(req, (uint8 *)blr->inbuf, 0, blr->encrypted);
 544
 545         SCVAL(req->inbuf, smb_com, SMBtrans2);
 546         SSVAL(params,0,0);
 547         /* Fake up max_data_bytes here - we know it fits. */
 548         send_trans2_replies(blr->fsp->conn, req, params, 2, NULL, 0, 0xffff);
 549         return True;
 550 }
 551
 552
 553 /****************************************************************************
 554  Process a blocking lock SMB.
 555  Returns True if we want to be removed from the list.
 556 *****************************************************************************/
 557
 558 static bool blocking_lock_record_process(blocking_lock_record *blr)
 559 {
 560         switch(blr->com_type) {
 561                 case SMBlockingX:
 562                         return process_lockingX(blr);
 563                 case SMBtrans2:
 564                 case SMBtranss2:
 565                         return process_trans2(blr);
 566                 default:
 567                         DEBUG(0,("blocking_lock_record_process: PANIC - unknown type on blocking lock queue - exiting.!\n"));
 568                         exit_server("PANIC - unknown type on blocking lock queue");
 569         }
 570         return False; /* Keep compiler happy. */
 571 }
 572
 573 /****************************************************************************
 574  Cancel entries by fnum from the blocking lock pending queue.
 575 *****************************************************************************/
 576
 577 void cancel_pending_lock_requests_by_fid(files_struct *fsp, struct byte_range_lock *br_lck)
 578 {
 579         blocking_lock_record *blr, *next = NULL;
 580
 581         for(blr = blocking_lock_queue; blr; blr = next) {
 582                 next = blr->next;
 583                 if(blr->fsp->fnum == fsp->fnum) {
 584                         unsigned char locktype = 0;
 585
 586                         if (blr->com_type == SMBlockingX) {
 587                                 locktype = CVAL(blr->inbuf,smb_vwv3);
 588                         }
 589
 590                         if (br_lck) {
 591                                 DEBUG(10,("remove_pending_lock_requests_by_fid - removing request type %d for \
 592 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
 593
 594                                 brl_lock_cancel(br_lck,
 595                                         blr->lock_pid,
 596                                         procid_self(),
 597                                         blr->offset,
 598                                         blr->count,
 599                                         blr->lock_flav);
 600
 601                                 blocking_lock_cancel(fsp,
 602                                         blr->lock_pid,
 603                                         blr->offset,
 604                                         blr->count,
 605                                         blr->lock_flav,
 606                                         locktype,
 607                                         NT_STATUS_RANGE_NOT_LOCKED);
 608                         }
 609                         /* We're closing the file fsp here, so ensure
 610                          * we don't have a dangling pointer. */
 611                         blr->fsp = NULL;
 612                 }
 613         }
 614 }
 615
 616 /****************************************************************************
 617  Delete entries by mid from the blocking lock pending queue. Always send reply.
 618 *****************************************************************************/
 619
 620 void remove_pending_lock_requests_by_mid(int mid)
 621 {
 622         blocking_lock_record *blr, *next = NULL;
 623
 624         for(blr = blocking_lock_queue; blr; blr = next) {
 625                 next = blr->next;
 626                 if(SVAL(blr->inbuf,smb_mid) == mid) {
 627                         files_struct *fsp = blr->fsp;
 628                         struct byte_range_lock *br_lck = brl_get_locks(talloc_tos(), fsp);
 629
 630                         if (br_lck) {
 631                                 DEBUG(10,("remove_pending_lock_requests_by_mid - removing request type %d for \
 632 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
 633
 634                                 brl_lock_cancel(br_lck,
 635                                         blr->lock_pid,
 636                                         procid_self(),
 637                                         blr->offset,
 638                                         blr->count,
 639                                         blr->lock_flav);
 640                                 TALLOC_FREE(br_lck);
 641                         }
 642
 643                         blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
 644                         DLIST_REMOVE(blocking_lock_queue, blr);
 645                         free_blocking_lock_record(blr);
 646                 }
 647         }
 648 }
 649
 650 /****************************************************************************
 651  Is this mid a blocking lock request on the queue ?
 652 *****************************************************************************/
 653
 654 bool blocking_lock_was_deferred(int mid)
 655 {
 656         blocking_lock_record *blr, *next = NULL;
 657
 658         for(blr = blocking_lock_queue; blr; blr = next) {
 659                 next = blr->next;
 660                 if(SVAL(blr->inbuf,smb_mid) == mid) {
 661                         return True;
 662                 }
 663         }
 664         return False;
 665 }
 666
 667 /****************************************************************************
 668   Set a flag as an unlock request affects one of our pending locks.
 669 *****************************************************************************/
 670
 671 static void received_unlock_msg(struct messaging_context *msg,
 672                                 void *private_data,
 673                                 uint32_t msg_type,
 674                                 struct server_id server_id,
 675                                 DATA_BLOB *data)
 676 {
 677         DEBUG(10,("received_unlock_msg\n"));
 678         process_blocking_lock_queue();
 679 }
 680
 681 /****************************************************************************
 682  Process the blocking lock queue. Note that this is only called as root.
 683 *****************************************************************************/
 684
 685 static void process_blocking_lock_queue(void)
 686 {
 687         struct timeval tv_curr = timeval_current();
 688         blocking_lock_record *blr, *next = NULL;
 689         bool recalc_timeout = False;
 690
 691         /*
 692          * Go through the queue and see if we can get any of the locks.
 693          */
 694
 695         for (blr = blocking_lock_queue; blr; blr = next) {
 696                 connection_struct *conn = NULL;
 697                 uint16 vuid;
 698                 files_struct *fsp = NULL;
 699
 700                 next = blr->next;
 701
 702                 /*
 703                  * Ensure we don't have any old chain_fsp values
 704                  * sitting around....
 705                  */
 706                 chain_size = 0;
 707                 fsp = blr->fsp;
 708
 709                 conn = conn_find(SVAL(blr->inbuf,smb_tid));
 710                 vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID :
 711                                 SVAL(blr->inbuf,smb_uid);
 712
 713                 DEBUG(5,("process_blocking_lock_queue: examining pending lock fnum = %d for file %s\n",
 714                         fsp->fnum, fsp->fsp_name ));
 715
 716                 if(!change_to_user(conn,vuid)) {
 717                         struct byte_range_lock *br_lck = brl_get_locks(talloc_tos(), fsp);
 718
 719                         /*
 720                          * Remove the entry and return an error to the client.
 721                          */
 722
 723                         if (br_lck) {
 724                                 brl_lock_cancel(br_lck,
 725                                         blr->lock_pid,
 726                                         procid_self(),
 727                                         blr->offset,
 728                                         blr->count,
 729                                         blr->lock_flav);
 730                                 TALLOC_FREE(br_lck);
 731                         }
 732
 733                         DEBUG(0,("process_blocking_lock_queue: Unable to become user vuid=%d.\n",
 734                                 vuid ));
 735                         blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
 736                         DLIST_REMOVE(blocking_lock_queue, blr);
 737                         free_blocking_lock_record(blr);
 738                         recalc_timeout = True;
 739                         continue;
 740                 }
 741
 742                 if(!set_current_service(conn,SVAL(blr->inbuf,smb_flg),True)) {
 743                         struct byte_range_lock *br_lck = brl_get_locks(talloc_tos(), fsp);
 744
 745                         /*
 746                          * Remove the entry and return an error to the client.
 747                          */
 748
 749                         if (br_lck) {
 750                                 brl_lock_cancel(br_lck,
 751                                         blr->lock_pid,
 752                                         procid_self(),
 753                                         blr->offset,
 754                                         blr->count,
 755                                         blr->lock_flav);
 756                                 TALLOC_FREE(br_lck);
 757                         }
 758
 759                         DEBUG(0,("process_blocking_lock_queue: Unable to become service Error was %s.\n", strerror(errno) ));
 760                         blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
 761                         DLIST_REMOVE(blocking_lock_queue, blr);
 762                         free_blocking_lock_record(blr);
 763                         recalc_timeout = True;
 764                         change_to_root_user();
 765                         continue;
 766                 }
 767
 768                 /*
 769                  * Go through the remaining locks and try and obtain them.
 770                  * The call returns True if all locks were obtained successfully
 771                  * and False if we still need to wait.
 772                  */
 773
 774                 if(blocking_lock_record_process(blr)) {
 775                         struct byte_range_lock *br_lck = brl_get_locks(talloc_tos(), fsp);
 776
 777                         if (br_lck) {
 778                                 brl_lock_cancel(br_lck,
 779                                         blr->lock_pid,
 780                                         procid_self(),
 781                                         blr->offset,
 782                                         blr->count,
 783                                         blr->lock_flav);
 784                                 TALLOC_FREE(br_lck);
 785                         }
 786
 787                         DLIST_REMOVE(blocking_lock_queue, blr);
 788                         free_blocking_lock_record(blr);
 789                         recalc_timeout = True;
 790                         change_to_root_user();
 791                         continue;
 792                 }
 793
 794                 change_to_root_user();
 795
 796                 /*
 797                  * We couldn't get the locks for this record on the list.
 798                  * If the time has expired, return a lock error.
 799                  */
 800
 801                 if (!timeval_is_zero(&blr->expire_time) && timeval_compare(&blr->expire_time, &tv_curr) <= 0) {
 802                         struct byte_range_lock *br_lck = brl_get_locks(talloc_tos(), fsp);
 803
 804                         /*
 805                          * Lock expired - throw away all previously
 806                          * obtained locks and return lock error.
 807                          */
 808
 809                         if (br_lck) {
 810                                 DEBUG(5,("process_blocking_lock_queue: pending lock fnum = %d for file %s timed out.\n",
 811                                         fsp->fnum, fsp->fsp_name ));
 812
 813                                 brl_lock_cancel(br_lck,
 814                                         blr->lock_pid,
 815                                         procid_self(),
 816                                         blr->offset,
 817                                         blr->count,
 818                                         blr->lock_flav);
 819                                 TALLOC_FREE(br_lck);
 820                         }
 821
 822                         blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
 823                         DLIST_REMOVE(blocking_lock_queue, blr);
 824                         free_blocking_lock_record(blr);
 825                         recalc_timeout = True;
 826                 }
 827         }
 828
 829         if (recalc_timeout) {
 830                 recalc_brl_timeout();
 831         }
 832 }
 833
 834 /****************************************************************************
 835  Handle a cancel message. Lock already moved onto the cancel queue.
 836 *****************************************************************************/
 837
 838 #define MSG_BLOCKING_LOCK_CANCEL_SIZE (sizeof(blocking_lock_record *) + sizeof(NTSTATUS))
 839
 840 static void process_blocking_lock_cancel_message(struct messaging_context *ctx,
 841                                                  void *private_data,
 842                                                  uint32_t msg_type,
 843                                                  struct server_id server_id,
 844                                                  DATA_BLOB *data)
 845 {
 846         NTSTATUS err;
 847         const char *msg = (const char *)data->data;
 848         blocking_lock_record *blr;
 849
 850         if (data->data == NULL) {
 851                 smb_panic("process_blocking_lock_cancel_message: null msg");
 852         }
 853
 854         if (data->length != MSG_BLOCKING_LOCK_CANCEL_SIZE) {
 855                 DEBUG(0, ("process_blocking_lock_cancel_message: "
 856                           "Got invalid msg len %d\n", (int)data->length));
 857                 smb_panic("process_blocking_lock_cancel_message: bad msg");
 858         }
 859
 860         memcpy(&blr, msg, sizeof(blr));
 861         memcpy(&err, &msg[sizeof(blr)], sizeof(NTSTATUS));
 862
 863         DEBUG(10,("process_blocking_lock_cancel_message: returning error %s\n",
 864                 nt_errstr(err) ));
 865
 866         blocking_lock_reply_error(blr, err);
 867         DLIST_REMOVE(blocking_lock_cancelled_queue, blr);
 868         free_blocking_lock_record(blr);
 869 }
 870
 871 /****************************************************************************
 872  Send ourselves a blocking lock cancelled message. Handled asynchronously above.
 873 *****************************************************************************/
 874
 875 bool blocking_lock_cancel(files_struct *fsp,
 876                         uint32 lock_pid,
 877                         uint64_t offset,
 878                         uint64_t count,
 879                         enum brl_flavour lock_flav,
 880                         unsigned char locktype,
 881                         NTSTATUS err)
 882 {
 883         static bool initialized;
 884         char msg[MSG_BLOCKING_LOCK_CANCEL_SIZE];
 885         blocking_lock_record *blr;
 886
 887         if (!initialized) {
 888                 /* Register our message. */
 889                 messaging_register(smbd_messaging_context(), NULL,
 890                                    MSG_SMB_BLOCKING_LOCK_CANCEL,
 891                                    process_blocking_lock_cancel_message);
 892
 893                 initialized = True;
 894         }
 895
 896         for (blr = blocking_lock_queue; blr; blr = blr->next) {
 897                 if (fsp == blr->fsp &&
 898                                 lock_pid == blr->lock_pid &&
 899                                 offset == blr->offset &&
 900                                 count == blr->count &&
 901                                 lock_flav == blr->lock_flav) {
 902                         break;
 903                 }
 904         }
 905
 906         if (!blr) {
 907                 return False;
 908         }
 909
 910         /* Check the flags are right. */
 911         if (blr->com_type == SMBlockingX &&
 912                 (locktype & LOCKING_ANDX_LARGE_FILES) !=
 913                         (CVAL(blr->inbuf,smb_vwv3) & LOCKING_ANDX_LARGE_FILES)) {
 914                 return False;
 915         }
 916
 917         /* Move to cancelled queue. */
 918         DLIST_REMOVE(blocking_lock_queue, blr);
 919         DLIST_ADD(blocking_lock_cancelled_queue, blr);
 920
 921         /* Create the message. */
 922         memcpy(msg, &blr, sizeof(blr));
 923         memcpy(&msg[sizeof(blr)], &err, sizeof(NTSTATUS));
 924
 925         messaging_send_buf(smbd_messaging_context(), procid_self(),
 926                            MSG_SMB_BLOCKING_LOCK_CANCEL,
 927                            (uint8 *)&msg, sizeof(msg));
 928
 929         return True;
 930 }