source/smbd/blocking.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Blocking Locking functions
   4    Copyright (C) Jeremy Allison 1998
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 #include "includes.h"
  22
  23 extern char *OutBuffer;
  24
  25 /****************************************************************************
  26  This is the structure to queue to implement blocking locks.
  27  notify. It consists of the requesting SMB and the expiry time.
  28 *****************************************************************************/
  29
  30 typedef struct {
  31   ubi_slNode msg_next;
  32   int com_type;
  33   files_struct *fsp;
  34   time_t expire_time;
  35   int lock_num;
  36   char *inbuf;
  37   int length;
  38 } blocking_lock_record;
  39
  40 static ubi_slList blocking_lock_queue = { NULL, (ubi_slNodePtr)&blocking_lock_queue, 0};
  41
  42 /****************************************************************************
  43  Destructor for the above structure.
  44 ****************************************************************************/
  45
  46 static void free_blocking_lock_record(blocking_lock_record *blr)
  47 {
  48   SAFE_FREE(blr->inbuf);
  49   SAFE_FREE(blr);
  50 }
  51
  52 /****************************************************************************
  53  Get the files_struct given a particular queued SMB.
  54 *****************************************************************************/
  55
  56 static files_struct *get_fsp_from_pkt(char *inbuf)
  57 {
  58   switch(CVAL(inbuf,smb_com)) {
  59   case SMBlock:
  60   case SMBlockread:
  61     return file_fsp(inbuf,smb_vwv0);
  62   case SMBlockingX:
  63     return file_fsp(inbuf,smb_vwv2);
  64   default:
  65     DEBUG(0,("get_fsp_from_pkt: PANIC - unknown type on blocking lock queue - exiting.!\n"));
  66     exit_server("PANIC - unknown type on blocking lock queue");
  67   }
  68   return NULL; /* Keep compiler happy. */
  69 }
  70
  71 /****************************************************************************
  72  Determine if this is a secondary element of a chained SMB.
  73   **************************************************************************/
  74
  75 static BOOL in_chained_smb(void)
  76 {
  77   return (chain_size != 0);
  78 }
  79
  80 /****************************************************************************
  81  Function to push a blocking lock request onto the lock queue.
  82 ****************************************************************************/
  83
  84 BOOL push_blocking_lock_request( char *inbuf, int length, int lock_timeout, int lock_num)
  85 {
  86   blocking_lock_record *blr;
  87
  88   if(in_chained_smb() ) {
  89     DEBUG(0,("push_blocking_lock_request: cannot queue a chained request (currently).\n"));
  90     return False;
  91   }
  92
  93   /*
  94    * Now queue an entry on the blocking lock queue. We setup
  95    * the expiration time here.
  96    */
  97
  98   if((blr = (blocking_lock_record *)malloc(sizeof(blocking_lock_record))) == NULL) {
  99     DEBUG(0,("push_blocking_lock_request: Malloc fail !\n" ));
 100     return False;
 101   }
 102
 103   if((blr->inbuf = (char *)malloc(length)) == NULL) {
 104     DEBUG(0,("push_blocking_lock_request: Malloc fail (2)!\n" ));
 105     SAFE_FREE(blr);
 106     return False;
 107   }
 108
 109   blr->com_type = CVAL(inbuf,smb_com);
 110   blr->fsp = get_fsp_from_pkt(inbuf);
 111   blr->expire_time = (lock_timeout == -1) ? (time_t)-1 : time(NULL) + (time_t)lock_timeout;
 112   blr->lock_num = lock_num;
 113   memcpy(blr->inbuf, inbuf, length);
 114   blr->length = length;
 115
 116   ubi_slAddTail(&blocking_lock_queue, blr);
 117
 118
 119   DEBUG(3,("push_blocking_lock_request: lock request length=%d blocked with expiry time %d (+%d) \
 120 for fnum = %d, name = %s\n", length, (int)blr->expire_time, lock_timeout,
 121         blr->fsp->fnum, blr->fsp->fsp_name ));
 122
 123   return True;
 124 }
 125
 126 /****************************************************************************
 127  Return a smd with a given size.
 128 *****************************************************************************/
 129
 130 static void send_blocking_reply(char *outbuf, int outsize)
 131 {
 132         if(outsize > 4)
 133                 smb_setlen(outbuf,outsize - 4);
 134
 135         if (!send_smb(smbd_server_fd(),outbuf))
 136                 exit_server("send_blocking_reply: send_smb failed.");
 137 }
 138
 139 /****************************************************************************
 140  Return a lockingX success SMB.
 141 *****************************************************************************/
 142
 143 static void reply_lockingX_success(blocking_lock_record *blr)
 144 {
 145   char *outbuf = OutBuffer;
 146   int bufsize = BUFFER_SIZE;
 147   char *inbuf = blr->inbuf;
 148   int outsize = 0;
 149
 150   construct_reply_common(inbuf, outbuf);
 151   set_message(outbuf,2,0,True);
 152
 153   /*
 154    * As this message is a lockingX call we must handle
 155    * any following chained message correctly.
 156    * This is normally handled in construct_reply(),
 157    * but as that calls switch_message, we can't use
 158    * that here and must set up the chain info manually.
 159    */
 160
 161   outsize = chain_reply(inbuf,outbuf,blr->length,bufsize);
 162
 163   outsize += chain_size;
 164
 165   send_blocking_reply(outbuf,outsize);
 166 }
 167
 168 /****************************************************************************
 169  Return a generic lock fail error blocking call.
 170 *****************************************************************************/
 171
 172 static void generic_blocking_lock_error(blocking_lock_record *blr, NTSTATUS status)
 173 {
 174         char *outbuf = OutBuffer;
 175         char *inbuf = blr->inbuf;
 176         construct_reply_common(inbuf, outbuf);
 177
 178         /* whenever a timeout is given w2k maps LOCK_NOT_GRANTED to
 179            FILE_LOCK_CONFLICT! (tridge) */
 180         if (NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) {
 181                 status = NT_STATUS_FILE_LOCK_CONFLICT;
 182         }
 183
 184         ERROR_NT(status);
 185         if (!send_smb(smbd_server_fd(),outbuf))
 186                 exit_server("generic_blocking_lock_error: send_smb failed.");
 187 }
 188
 189 /****************************************************************************
 190  Return a lock fail error for a lockingX call. Undo all the locks we have
 191  obtained first.
 192 *****************************************************************************/
 193
 194 static void reply_lockingX_error(blocking_lock_record *blr, NTSTATUS status)
 195 {
 196         char *inbuf = blr->inbuf;
 197         files_struct *fsp = blr->fsp;
 198         connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
 199         uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
 200         SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT) 0;
 201         uint16 lock_pid;
 202         unsigned char locktype = CVAL(inbuf,smb_vwv3);
 203         BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
 204         char *data;
 205         int i;
 206
 207         data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
 208
 209         /*
 210          * Data now points at the beginning of the list
 211          * of smb_lkrng structs.
 212          */
 213
 214         /*
 215          * Ensure we don't do a remove on the lock that just failed,
 216          * as under POSIX rules, if we have a lock already there, we
 217          * will delete it (and we shouldn't) .....
 218          */
 219
 220         for(i = blr->lock_num - 1; i >= 0; i--) {
 221                 BOOL err;
 222
 223                 lock_pid = get_lock_pid( data, i, large_file_format);
 224                 count = get_lock_count( data, i, large_file_format);
 225                 offset = get_lock_offset( data, i, large_file_format, &err);
 226
 227                 /*
 228                  * We know err cannot be set as if it was the lock
 229                  * request would never have been queued. JRA.
 230                  */
 231
 232                 do_unlock(fsp,conn,lock_pid,count,offset);
 233         }
 234
 235         generic_blocking_lock_error(blr, status);
 236 }
 237
 238 /****************************************************************************
 239  Return a lock fail error.
 240 *****************************************************************************/
 241
 242 static void blocking_lock_reply_error(blocking_lock_record *blr, NTSTATUS status)
 243 {
 244         switch(blr->com_type) {
 245         case SMBlock:
 246         case SMBlockread:
 247                 generic_blocking_lock_error(blr, status);
 248                 break;
 249         case SMBlockingX:
 250                 reply_lockingX_error(blr, status);
 251                 break;
 252         default:
 253                 DEBUG(0,("blocking_lock_reply_error: PANIC - unknown type on blocking lock queue - exiting.!\n"));
 254                 exit_server("PANIC - unknown type on blocking lock queue");
 255         }
 256 }
 257
 258 /****************************************************************************
 259  Attempt to finish off getting all pending blocking locks for a lockread call.
 260  Returns True if we want to be removed from the list.
 261 *****************************************************************************/
 262
 263 static BOOL process_lockread(blocking_lock_record *blr)
 264 {
 265         char *outbuf = OutBuffer;
 266         char *inbuf = blr->inbuf;
 267         ssize_t nread = -1;
 268         char *data, *p;
 269         int outsize = 0;
 270         SMB_OFF_T startpos;
 271         size_t numtoread;
 272         NTSTATUS status;
 273         connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
 274         files_struct *fsp = blr->fsp;
 275
 276         numtoread = SVAL(inbuf,smb_vwv1);
 277         startpos = IVAL(inbuf,smb_vwv2);
 278
 279         numtoread = MIN(BUFFER_SIZE-outsize,numtoread);
 280         data = smb_buf(outbuf) + 3;
 281
 282         status = do_lock_spin( fsp, conn, SVAL(inbuf,smb_pid), (SMB_BIG_UINT)numtoread,
 283                           (SMB_BIG_UINT)startpos, READ_LOCK);
 284         if (NT_STATUS_V(status)) {
 285                 if (!NT_STATUS_EQUAL(status,NT_STATUS_LOCK_NOT_GRANTED) &&
 286                         !NT_STATUS_EQUAL(status,NT_STATUS_FILE_LOCK_CONFLICT)) {
 287                         /*
 288                          * We have other than a "can't get lock"
 289                          * error. Send an error.
 290                          * Return True so we get dequeued.
 291                          */
 292                         generic_blocking_lock_error(blr, status);
 293                         return True;
 294                 }
 295
 296                 /*
 297                  * Still waiting for lock....
 298                  */
 299
 300                 DEBUG(10,("process_lockread: failed to get lock for file = %s. Still waiting....\n",
 301                           fsp->fsp_name));
 302                 return False;
 303         }
 304
 305         nread = read_file(fsp,data,startpos,numtoread);
 306
 307         if (nread < 0) {
 308                 generic_blocking_lock_error(blr,NT_STATUS_ACCESS_DENIED);
 309                 return True;
 310         }
 311
 312         construct_reply_common(inbuf, outbuf);
 313         outsize = set_message(outbuf,5,0,True);
 314
 315         outsize += nread;
 316         SSVAL(outbuf,smb_vwv0,nread);
 317         SSVAL(outbuf,smb_vwv5,nread+3);
 318         p = smb_buf(outbuf);
 319         *p++ = 1;
 320         SSVAL(p,0,nread); p += 2;
 321         set_message_end(outbuf, p+nread);
 322
 323         DEBUG(3, ( "process_lockread file = %s, fnum=%d num=%d nread=%d\n",
 324                    fsp->fsp_name, fsp->fnum, (int)numtoread, (int)nread ) );
 325
 326         send_blocking_reply(outbuf,outsize);
 327         return True;
 328 }
 329
 330 /****************************************************************************
 331  Attempt to finish off getting all pending blocking locks for a lock call.
 332  Returns True if we want to be removed from the list.
 333 *****************************************************************************/
 334
 335 static BOOL process_lock(blocking_lock_record *blr)
 336 {
 337         char *outbuf = OutBuffer;
 338         char *inbuf = blr->inbuf;
 339         int outsize;
 340         SMB_OFF_T count = 0, offset = 0;
 341         NTSTATUS status;
 342         connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
 343         files_struct *fsp = blr->fsp;
 344
 345         count = IVAL(inbuf,smb_vwv1);
 346         offset = IVAL(inbuf,smb_vwv3);
 347
 348         errno = 0;
 349         status = do_lock_spin(fsp, conn, SVAL(inbuf,smb_pid), (SMB_BIG_UINT)count,
 350                          (SMB_BIG_UINT)offset, WRITE_LOCK);
 351         if (NT_STATUS_IS_ERR(status)) {
 352                 if (!NT_STATUS_EQUAL(status,NT_STATUS_LOCK_NOT_GRANTED) &&
 353                         !NT_STATUS_EQUAL(status,NT_STATUS_FILE_LOCK_CONFLICT)) {
 354                         /*
 355                          * We have other than a "can't get lock"
 356                          * error. Send an error.
 357                          * Return True so we get dequeued.
 358                          */
 359
 360                         blocking_lock_reply_error(blr, status);
 361                         return True;
 362                 }
 363                 /*
 364                  * Still can't get the lock - keep waiting.
 365                  */
 366                 DEBUG(10,("process_lock: failed to get lock for file = %s. Still waiting....\n",
 367                           fsp->fsp_name));
 368                 return False;
 369         }
 370
 371         /*
 372          * Success - we got the lock.
 373          */
 374
 375         DEBUG(3,("process_lock : file=%s fnum=%d offset=%.0f count=%.0f\n",
 376                  fsp->fsp_name, fsp->fnum, (double)offset, (double)count));
 377
 378         construct_reply_common(inbuf, outbuf);
 379         outsize = set_message(outbuf,0,0,True);
 380         send_blocking_reply(outbuf,outsize);
 381         return True;
 382 }
 383
 384 /****************************************************************************
 385  Attempt to finish off getting all pending blocking locks for a lockingX call.
 386  Returns True if we want to be removed from the list.
 387 *****************************************************************************/
 388
 389 static BOOL process_lockingX(blocking_lock_record *blr)
 390 {
 391         char *inbuf = blr->inbuf;
 392         unsigned char locktype = CVAL(inbuf,smb_vwv3);
 393         files_struct *fsp = blr->fsp;
 394         connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
 395         uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
 396         uint16 num_locks = SVAL(inbuf,smb_vwv7);
 397         SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT)0;
 398         uint16 lock_pid;
 399         BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
 400         char *data;
 401         NTSTATUS status = NT_STATUS_OK;
 402
 403         data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
 404
 405         /*
 406          * Data now points at the beginning of the list
 407          * of smb_lkrng structs.
 408          */
 409
 410         for(; blr->lock_num < num_locks; blr->lock_num++) {
 411                 BOOL err;
 412
 413                 lock_pid = get_lock_pid( data, blr->lock_num, large_file_format);
 414                 count = get_lock_count( data, blr->lock_num, large_file_format);
 415                 offset = get_lock_offset( data, blr->lock_num, large_file_format, &err);
 416
 417                 /*
 418                  * We know err cannot be set as if it was the lock
 419                  * request would never have been queued. JRA.
 420                  */
 421                 errno = 0;
 422                 status = do_lock_spin(fsp,conn,lock_pid,count,offset,
 423                                  ((locktype & 1) ? READ_LOCK : WRITE_LOCK));
 424                 if (NT_STATUS_IS_ERR(status)) break;
 425         }
 426
 427         if(blr->lock_num == num_locks) {
 428                 /*
 429                  * Success - we got all the locks.
 430                  */
 431
 432                 DEBUG(3,("process_lockingX file = %s, fnum=%d type=%d num_locks=%d\n",
 433                          fsp->fsp_name, fsp->fnum, (unsigned int)locktype, num_locks) );
 434
 435                 reply_lockingX_success(blr);
 436                 return True;
 437         } else if (!NT_STATUS_EQUAL(status,NT_STATUS_LOCK_NOT_GRANTED) &&
 438                         !NT_STATUS_EQUAL(status,NT_STATUS_FILE_LOCK_CONFLICT)) {
 439                         /*
 440                          * We have other than a "can't get lock"
 441                          * error. Free any locks we had and return an error.
 442                          * Return True so we get dequeued.
 443                          */
 444
 445                 blocking_lock_reply_error(blr, status);
 446                 return True;
 447         }
 448
 449         /*
 450          * Still can't get all the locks - keep waiting.
 451          */
 452
 453         DEBUG(10,("process_lockingX: only got %d locks of %d needed for file %s, fnum = %d. \
 454 Waiting....\n",
 455                   blr->lock_num, num_locks, fsp->fsp_name, fsp->fnum));
 456
 457         return False;
 458 }
 459
 460 /****************************************************************************
 461  Process a blocking lock SMB.
 462  Returns True if we want to be removed from the list.
 463 *****************************************************************************/
 464
 465 static BOOL blocking_lock_record_process(blocking_lock_record *blr)
 466 {
 467   switch(blr->com_type) {
 468   case SMBlock:
 469     return process_lock(blr);
 470   case SMBlockread:
 471     return process_lockread(blr);
 472   case SMBlockingX:
 473     return process_lockingX(blr);
 474   default:
 475     DEBUG(0,("blocking_lock_record_process: PANIC - unknown type on blocking lock queue - exiting.!\n"));
 476     exit_server("PANIC - unknown type on blocking lock queue");
 477   }
 478   return False; /* Keep compiler happy. */
 479 }
 480
 481 /****************************************************************************
 482  Delete entries by fnum from the blocking lock pending queue.
 483 *****************************************************************************/
 484
 485 void remove_pending_lock_requests_by_fid(files_struct *fsp)
 486 {
 487   blocking_lock_record *blr = (blocking_lock_record *)ubi_slFirst( &blocking_lock_queue );
 488   blocking_lock_record *prev = NULL;
 489
 490   while(blr != NULL) {
 491     if(blr->fsp->fnum == fsp->fnum) {
 492
 493       DEBUG(10,("remove_pending_lock_requests_by_fid - removing request type %d for \
 494 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
 495
 496       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 497       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 498       continue;
 499     }
 500
 501     prev = blr;
 502     blr = (blocking_lock_record *)ubi_slNext(blr);
 503   }
 504 }
 505
 506 /****************************************************************************
 507  Delete entries by mid from the blocking lock pending queue. Always send reply.
 508 *****************************************************************************/
 509
 510 void remove_pending_lock_requests_by_mid(int mid)
 511 {
 512   blocking_lock_record *blr = (blocking_lock_record *)ubi_slFirst( &blocking_lock_queue );
 513   blocking_lock_record *prev = NULL;
 514
 515   while(blr != NULL) {
 516     if(SVAL(blr->inbuf,smb_mid) == mid) {
 517       files_struct *fsp = blr->fsp;
 518
 519       DEBUG(10,("remove_pending_lock_requests_by_mid - removing request type %d for \
 520 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
 521
 522       blocking_lock_reply_error(blr,NT_STATUS_CANCELLED);
 523       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 524       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 525       continue;
 526     }
 527
 528     prev = blr;
 529     blr = (blocking_lock_record *)ubi_slNext(blr);
 530   }
 531 }
 532
 533 /****************************************************************************
 534  Return the number of seconds to the next blocking locks timeout, or default_timeout.
 535 *****************************************************************************/
 536
 537 BOOL blocking_locks_timeout(unsigned default_timeout)
 538 {
 539         unsigned timeout = default_timeout;
 540         time_t t;
 541         blocking_lock_record *blr = (blocking_lock_record *)ubi_slFirst(&blocking_lock_queue);
 542
 543         /* note that we avoid the time() syscall if there are no blocking locks */
 544         if (!blr) {
 545                 return timeout;
 546         }
 547
 548         t = time(NULL);
 549
 550         while (blr) {
 551                 if (timeout > (blr->expire_time - t)) {
 552                         timeout = blr->expire_time - t;
 553                 }
 554                 blr = (blocking_lock_record *)ubi_slNext(blr);
 555         }
 556
 557         if (timeout < 1) {
 558                 timeout = 1;
 559         }
 560
 561         return timeout;
 562 }
 563
 564 /****************************************************************************
 565  Process the blocking lock queue. Note that this is only called as root.
 566 *****************************************************************************/
 567
 568 void process_blocking_lock_queue(time_t t)
 569 {
 570   blocking_lock_record *blr = (blocking_lock_record *)ubi_slFirst( &blocking_lock_queue );
 571   blocking_lock_record *prev = NULL;
 572
 573   if(blr == NULL)
 574     return;
 575
 576   /*
 577    * Go through the queue and see if we can get any of the locks.
 578    */
 579
 580   while(blr != NULL) {
 581     connection_struct *conn = NULL;
 582     uint16 vuid;
 583     files_struct *fsp = NULL;
 584
 585     /*
 586      * Ensure we don't have any old chain_fsp values
 587      * sitting around....
 588      */
 589     chain_size = 0;
 590     file_chain_reset();
 591     fsp = blr->fsp;
 592
 593     conn = conn_find(SVAL(blr->inbuf,smb_tid));
 594     vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID :
 595                   SVAL(blr->inbuf,smb_uid);
 596
 597     DEBUG(5,("process_blocking_lock_queue: examining pending lock fnum = %d for file %s\n",
 598           fsp->fnum, fsp->fsp_name ));
 599
 600     if((blr->expire_time != -1) && (blr->expire_time <= t)) {
 601       /*
 602        * Lock expired - throw away all previously
 603        * obtained locks and return lock error.
 604        */
 605       DEBUG(5,("process_blocking_lock_queue: pending lock fnum = %d for file %s timed out.\n",
 606           fsp->fnum, fsp->fsp_name ));
 607
 608       blocking_lock_reply_error(blr,NT_STATUS_FILE_LOCK_CONFLICT);
 609       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 610       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 611       continue;
 612     }
 613
 614     if(!change_to_user(conn,vuid)) {
 615       DEBUG(0,("process_blocking_lock_queue: Unable to become user vuid=%d.\n",
 616             vuid ));
 617       /*
 618        * Remove the entry and return an error to the client.
 619        */
 620       blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
 621       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 622       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 623       continue;
 624     }
 625
 626     if(!set_current_service(conn,True)) {
 627       DEBUG(0,("process_blocking_lock_queue: Unable to become service Error was %s.\n", strerror(errno) ));
 628       /*
 629        * Remove the entry and return an error to the client.
 630        */
 631       blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
 632       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 633       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 634       change_to_root_user();
 635       continue;
 636     }
 637
 638     /*
 639      * Go through the remaining locks and try and obtain them.
 640      * The call returns True if all locks were obtained successfully
 641      * and False if we still need to wait.
 642      */
 643
 644     if(blocking_lock_record_process(blr)) {
 645       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 646       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 647       change_to_root_user();
 648       continue;
 649     }
 650
 651     change_to_root_user();
 652
 653     /*
 654      * Move to the next in the list.
 655      */
 656     prev = blr;
 657     blr = (blocking_lock_record *)ubi_slNext(blr);
 658   }
 659 }