source3/locking/posix.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Locking functions
   4    Copyright (C) Jeremy Allison 1992-2000
   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    Revision History:
  21
  22    POSIX locking support. Jeremy Allison (jeremy@valinux.com), Apr. 2000.
  23 */
  24
  25 #include "includes.h"
  26
  27 #undef DBGC_CLASS
  28 #define DBGC_CLASS DBGC_LOCKING
  29
  30 /*
  31  * The POSIX locking database handle.
  32  */
  33
  34 static TDB_CONTEXT *posix_lock_tdb;
  35
  36 /*
  37  * The pending close database handle.
  38  */
  39
  40 static TDB_CONTEXT *posix_pending_close_tdb;
  41
  42 /*
  43  * The data in POSIX lock records is an unsorted linear array of these
  44  * records.  It is unnecessary to store the count as tdb provides the
  45  * size of the record.
  46  */
  47
  48 struct posix_lock {
  49         int fd;
  50         SMB_OFF_T start;
  51         SMB_OFF_T size;
  52         int lock_type;
  53 };
  54
  55 /*
  56  * The data in POSIX pending close records is an unsorted linear array of int
  57  * records.  It is unnecessary to store the count as tdb provides the
  58  * size of the record.
  59  */
  60
  61 /* The key used in both the POSIX databases. */
  62
  63 struct posix_lock_key {
  64         SMB_DEV_T device;
  65         SMB_INO_T inode;
  66 };
  67
  68 /*******************************************************************
  69  Form a static locking key for a dev/inode pair.
  70 ******************************************************************/
  71
  72 static TDB_DATA locking_key(SMB_DEV_T dev, SMB_INO_T inode)
  73 {
  74         static struct posix_lock_key key;
  75         TDB_DATA kbuf;
  76
  77         memset(&key, '\0', sizeof(key));
  78         key.device = dev;
  79         key.inode = inode;
  80         kbuf.dptr = (char *)&key;
  81         kbuf.dsize = sizeof(key);
  82         return kbuf;
  83 }
  84
  85 /*******************************************************************
  86  Convenience function to get a key from an fsp.
  87 ******************************************************************/
  88
  89 static TDB_DATA locking_key_fsp(files_struct *fsp)
  90 {
  91         return locking_key(fsp->dev, fsp->inode);
  92 }
  93
  94 /****************************************************************************
  95  Add an fd to the pending close tdb.
  96 ****************************************************************************/
  97
  98 static BOOL add_fd_to_close_entry(files_struct *fsp)
  99 {
 100         TDB_DATA kbuf = locking_key_fsp(fsp);
 101         TDB_DATA dbuf;
 102
 103         dbuf.dptr = NULL;
 104         dbuf.dsize = 0;
 105
 106         dbuf = tdb_fetch(posix_pending_close_tdb, kbuf);
 107
 108         dbuf.dptr = SMB_REALLOC(dbuf.dptr, dbuf.dsize + sizeof(int));
 109         if (!dbuf.dptr) {
 110                 DEBUG(0,("add_fd_to_close_entry: Realloc fail !\n"));
 111                 return False;
 112         }
 113
 114         memcpy(dbuf.dptr + dbuf.dsize, &fsp->fh->fd, sizeof(int));
 115         dbuf.dsize += sizeof(int);
 116
 117         if (tdb_store(posix_pending_close_tdb, kbuf, dbuf, TDB_REPLACE) == -1) {
 118                 DEBUG(0,("add_fd_to_close_entry: tdb_store fail !\n"));
 119         }
 120
 121         SAFE_FREE(dbuf.dptr);
 122         return True;
 123 }
 124
 125 /****************************************************************************
 126  Remove all fd entries for a specific dev/inode pair from the tdb.
 127 ****************************************************************************/
 128
 129 static void delete_close_entries(files_struct *fsp)
 130 {
 131         TDB_DATA kbuf = locking_key_fsp(fsp);
 132
 133         if (tdb_delete(posix_pending_close_tdb, kbuf) == -1)
 134                 DEBUG(0,("delete_close_entries: tdb_delete fail !\n"));
 135 }
 136
 137 /****************************************************************************
 138  Get the array of POSIX pending close records for an open fsp. Caller must
 139  free. Returns number of entries.
 140 ****************************************************************************/
 141
 142 static size_t get_posix_pending_close_entries(files_struct *fsp, int **entries)
 143 {
 144         TDB_DATA kbuf = locking_key_fsp(fsp);
 145         TDB_DATA dbuf;
 146         size_t count = 0;
 147
 148         *entries = NULL;
 149         dbuf.dptr = NULL;
 150
 151         dbuf = tdb_fetch(posix_pending_close_tdb, kbuf);
 152
 153         if (!dbuf.dptr) {
 154                 return 0;
 155         }
 156
 157         *entries = (int *)dbuf.dptr;
 158         count = (size_t)(dbuf.dsize / sizeof(int));
 159
 160         return count;
 161 }
 162
 163 /****************************************************************************
 164  Get the array of POSIX locks for an fsp. Caller must free. Returns
 165  number of entries.
 166 ****************************************************************************/
 167
 168 static size_t get_posix_lock_entries(files_struct *fsp, struct posix_lock **entries)
 169 {
 170         TDB_DATA kbuf = locking_key_fsp(fsp);
 171         TDB_DATA dbuf;
 172         size_t count = 0;
 173
 174         *entries = NULL;
 175
 176         dbuf.dptr = NULL;
 177
 178         dbuf = tdb_fetch(posix_lock_tdb, kbuf);
 179
 180         if (!dbuf.dptr) {
 181                 return 0;
 182         }
 183
 184         *entries = (struct posix_lock *)dbuf.dptr;
 185         count = (size_t)(dbuf.dsize / sizeof(struct posix_lock));
 186
 187         return count;
 188 }
 189
 190 /****************************************************************************
 191  Deal with pending closes needed by POSIX locking support.
 192  Note that posix_locking_close_file() is expected to have been called
 193  to delete all locks on this fsp before this function is called.
 194 ****************************************************************************/
 195
 196 int fd_close_posix(struct connection_struct *conn, files_struct *fsp)
 197 {
 198         int saved_errno = 0;
 199         int ret;
 200         size_t count, i;
 201         struct posix_lock *entries = NULL;
 202         int *fd_array = NULL;
 203         BOOL locks_on_other_fds = False;
 204
 205         if (!lp_posix_locking(SNUM(conn))) {
 206                 /*
 207                  * No POSIX to worry about, just close.
 208                  */
 209                 ret = SMB_VFS_CLOSE(fsp,fsp->fh->fd);
 210                 fsp->fh->fd = -1;
 211                 return ret;
 212         }
 213
 214         /*
 215          * Get the number of outstanding POSIX locks on this dev/inode pair.
 216          */
 217
 218         count = get_posix_lock_entries(fsp, &entries);
 219
 220         /*
 221          * Check if there are any outstanding locks belonging to
 222          * other fd's. This should never be the case if posix_locking_close_file()
 223          * has been called first, but it never hurts to be *sure*.
 224          */
 225
 226         for (i = 0; i < count; i++) {
 227                 if (entries[i].fd != fsp->fh->fd) {
 228                         locks_on_other_fds = True;
 229                         break;
 230                 }
 231         }
 232
 233         if (locks_on_other_fds) {
 234
 235                 /*
 236                  * There are outstanding locks on this dev/inode pair on other fds.
 237                  * Add our fd to the pending close tdb and set fsp->fh->fd to -1.
 238                  */
 239
 240                 if (!add_fd_to_close_entry(fsp)) {
 241                         SAFE_FREE(entries);
 242                         return -1;
 243                 }
 244
 245                 SAFE_FREE(entries);
 246                 fsp->fh->fd = -1;
 247                 return 0;
 248         }
 249
 250         SAFE_FREE(entries);
 251
 252         /*
 253          * No outstanding POSIX locks. Get the pending close fd's
 254          * from the tdb and close them all.
 255          */
 256
 257         count = get_posix_pending_close_entries(fsp, &fd_array);
 258
 259         if (count) {
 260                 DEBUG(10,("fd_close_posix: doing close on %u fd's.\n", (unsigned int)count ));
 261
 262                 for(i = 0; i < count; i++) {
 263                         if (SMB_VFS_CLOSE(fsp,fd_array[i]) == -1) {
 264                                 saved_errno = errno;
 265                         }
 266                 }
 267
 268                 /*
 269                  * Delete all fd's stored in the tdb
 270                  * for this dev/inode pair.
 271                  */
 272
 273                 delete_close_entries(fsp);
 274         }
 275
 276         SAFE_FREE(fd_array);
 277
 278         /*
 279          * Finally close the fd associated with this fsp.
 280          */
 281
 282         ret = SMB_VFS_CLOSE(fsp,fsp->fh->fd);
 283
 284         if (saved_errno != 0) {
 285                 errno = saved_errno;
 286                 ret = -1;
 287         }
 288
 289         fsp->fh->fd = -1;
 290
 291         return ret;
 292 }
 293
 294 /****************************************************************************
 295  Debugging aid :-).
 296 ****************************************************************************/
 297
 298 static const char *posix_lock_type_name(int lock_type)
 299 {
 300         return (lock_type == F_RDLCK) ? "READ" : "WRITE";
 301 }
 302
 303 /****************************************************************************
 304  Delete a POSIX lock entry by index number. Used if the tdb add succeeds, but
 305  then the POSIX fcntl lock fails.
 306 ****************************************************************************/
 307
 308 static BOOL delete_posix_lock_entry_by_index(files_struct *fsp, size_t entry)
 309 {
 310         TDB_DATA kbuf = locking_key_fsp(fsp);
 311         TDB_DATA dbuf;
 312         struct posix_lock *locks;
 313         size_t count;
 314
 315         dbuf.dptr = NULL;
 316
 317         dbuf = tdb_fetch(posix_lock_tdb, kbuf);
 318
 319         if (!dbuf.dptr) {
 320                 DEBUG(10,("delete_posix_lock_entry_by_index: tdb_fetch failed !\n"));
 321                 goto fail;
 322         }
 323
 324         count = (size_t)(dbuf.dsize / sizeof(struct posix_lock));
 325         locks = (struct posix_lock *)dbuf.dptr;
 326
 327         if (count == 1) {
 328                 tdb_delete(posix_lock_tdb, kbuf);
 329         } else {
 330                 if (entry < count-1) {
 331                         memmove(&locks[entry], &locks[entry+1], sizeof(struct posix_lock)*((count-1) - entry));
 332                 }
 333                 dbuf.dsize -= sizeof(struct posix_lock);
 334                 tdb_store(posix_lock_tdb, kbuf, dbuf, TDB_REPLACE);
 335         }
 336
 337         SAFE_FREE(dbuf.dptr);
 338
 339         return True;
 340
 341  fail:
 342
 343         SAFE_FREE(dbuf.dptr);
 344         return False;
 345 }
 346
 347 /****************************************************************************
 348  Add an entry into the POSIX locking tdb. We return the index number of the
 349  added lock (used in case we need to delete *exactly* this entry). Returns
 350  False on fail, True on success.
 351 ****************************************************************************/
 352
 353 static BOOL add_posix_lock_entry(files_struct *fsp, SMB_OFF_T start, SMB_OFF_T size, int lock_type, size_t *pentry_num)
 354 {
 355         TDB_DATA kbuf = locking_key_fsp(fsp);
 356         TDB_DATA dbuf;
 357         struct posix_lock pl;
 358
 359         dbuf.dptr = NULL;
 360         dbuf.dsize = 0;
 361
 362         dbuf = tdb_fetch(posix_lock_tdb, kbuf);
 363
 364         *pentry_num = (size_t)(dbuf.dsize / sizeof(struct posix_lock));
 365
 366         /*
 367          * Add new record.
 368          */
 369
 370         pl.fd = fsp->fh->fd;
 371         pl.start = start;
 372         pl.size = size;
 373         pl.lock_type = lock_type;
 374
 375         dbuf.dptr = SMB_REALLOC(dbuf.dptr, dbuf.dsize + sizeof(struct posix_lock));
 376         if (!dbuf.dptr) {
 377                 DEBUG(0,("add_posix_lock_entry: Realloc fail !\n"));
 378                 goto fail;
 379         }
 380
 381         memcpy(dbuf.dptr + dbuf.dsize, &pl, sizeof(struct posix_lock));
 382         dbuf.dsize += sizeof(struct posix_lock);
 383
 384         if (tdb_store(posix_lock_tdb, kbuf, dbuf, TDB_REPLACE) == -1) {
 385                 DEBUG(0,("add_posix_lock: Failed to add lock entry on file %s\n", fsp->fsp_name));
 386                 goto fail;
 387         }
 388
 389         SAFE_FREE(dbuf.dptr);
 390
 391         DEBUG(10,("add_posix_lock: File %s: type = %s: start=%.0f size=%.0f: dev=%.0f inode=%.0f\n",
 392                         fsp->fsp_name, posix_lock_type_name(lock_type), (double)start, (double)size,
 393                         (double)fsp->dev, (double)fsp->inode ));
 394
 395         return True;
 396
 397  fail:
 398
 399         SAFE_FREE(dbuf.dptr);
 400         return False;
 401 }
 402
 403 /****************************************************************************
 404  Calculate if locks have any overlap at all.
 405 ****************************************************************************/
 406
 407 static BOOL does_lock_overlap(SMB_OFF_T start1, SMB_OFF_T size1, SMB_OFF_T start2, SMB_OFF_T size2)
 408 {
 409         if (start1 >= start2 && start1 <= start2 + size2)
 410                 return True;
 411
 412         if (start1 < start2 && start1 + size1 > start2)
 413                 return True;
 414
 415         return False;
 416 }
 417
 418 /****************************************************************************
 419  Delete an entry from the POSIX locking tdb. Returns a copy of the entry being
 420  deleted and the number of records that are overlapped by this one, or -1 on error.
 421 ****************************************************************************/
 422
 423 static int delete_posix_lock_entry(files_struct *fsp, SMB_OFF_T start, SMB_OFF_T size, struct posix_lock *pl)
 424 {
 425         TDB_DATA kbuf = locking_key_fsp(fsp);
 426         TDB_DATA dbuf;
 427         struct posix_lock *locks;
 428         size_t i, count;
 429         BOOL found = False;
 430         int num_overlapping_records = 0;
 431
 432         dbuf.dptr = NULL;
 433
 434         dbuf = tdb_fetch(posix_lock_tdb, kbuf);
 435
 436         if (!dbuf.dptr) {
 437                 DEBUG(10,("delete_posix_lock_entry: tdb_fetch failed !\n"));
 438                 goto fail;
 439         }
 440
 441         /* There are existing locks - find a match. */
 442         locks = (struct posix_lock *)dbuf.dptr;
 443         count = (size_t)(dbuf.dsize / sizeof(struct posix_lock));
 444
 445         /*
 446          * Search for and delete the first record that matches the
 447          * unlock criteria.
 448          */
 449
 450         for (i=0; i<count; i++) {
 451                 struct posix_lock *entry = &locks[i];
 452
 453                 if (entry->fd == fsp->fh->fd &&
 454                         entry->start == start &&
 455                         entry->size == size) {
 456
 457                         /* Make a copy if requested. */
 458                         if (pl)
 459                                 *pl = *entry;
 460
 461                         /* Found it - delete it. */
 462                         if (count == 1) {
 463                                 tdb_delete(posix_lock_tdb, kbuf);
 464                         } else {
 465                                 if (i < count-1) {
 466                                         memmove(&locks[i], &locks[i+1], sizeof(struct posix_lock)*((count-1) - i));
 467                                 }
 468                                 dbuf.dsize -= sizeof(struct posix_lock);
 469                                 tdb_store(posix_lock_tdb, kbuf, dbuf, TDB_REPLACE);
 470                         }
 471                         count--;
 472                         found = True;
 473                         break;
 474                 }
 475         }
 476
 477         if (!found)
 478                 goto fail;
 479
 480         /*
 481          * Count the number of entries that are
 482          * overlapped by this unlock request.
 483          */
 484
 485         for (i = 0; i < count; i++) {
 486                 struct posix_lock *entry = &locks[i];
 487
 488                 if (fsp->fh->fd == entry->fd &&
 489                         does_lock_overlap( start, size, entry->start, entry->size))
 490                                 num_overlapping_records++;
 491         }
 492
 493         DEBUG(10,("delete_posix_lock_entry: type = %s: start=%.0f size=%.0f, num_records = %d\n",
 494                         posix_lock_type_name(pl->lock_type), (double)pl->start, (double)pl->size,
 495                                 (unsigned int)num_overlapping_records ));
 496
 497         SAFE_FREE(dbuf.dptr);
 498
 499         return num_overlapping_records;
 500
 501  fail:
 502
 503         SAFE_FREE(dbuf.dptr);
 504         return -1;
 505 }
 506
 507 /****************************************************************************
 508  Utility function to map a lock type correctly depending on the open
 509  mode of a file.
 510 ****************************************************************************/
 511
 512 static int map_posix_lock_type( files_struct *fsp, enum brl_type lock_type)
 513 {
 514         if((lock_type == WRITE_LOCK) && !fsp->can_write) {
 515                 /*
 516                  * Many UNIX's cannot get a write lock on a file opened read-only.
 517                  * Win32 locking semantics allow this.
 518                  * Do the best we can and attempt a read-only lock.
 519                  */
 520                 DEBUG(10,("map_posix_lock_type: Downgrading write lock to read due to read-only file.\n"));
 521                 return F_RDLCK;
 522         }
 523 #if 0
 524         /* We no longer open files write-only. */
 525          else if((lock_type == READ_LOCK) && !fsp->can_read) {
 526                 /*
 527                  * Ditto for read locks on write only files.
 528                  */
 529                 DEBUG(10,("map_posix_lock_type: Changing read lock to write due to write-only file.\n"));
 530                 return F_WRLCK;
 531         }
 532 #endif
 533
 534         /*
 535          * This return should be the most normal, as we attempt
 536          * to always open files read/write.
 537          */
 538
 539         return (lock_type == READ_LOCK) ? F_RDLCK : F_WRLCK;
 540 }
 541
 542 /****************************************************************************
 543  Check to see if the given unsigned lock range is within the possible POSIX
 544  range. Modifies the given args to be in range if possible, just returns
 545  False if not.
 546 ****************************************************************************/
 547
 548 static BOOL posix_lock_in_range(SMB_OFF_T *offset_out, SMB_OFF_T *count_out,
 549                                 SMB_BIG_UINT u_offset, SMB_BIG_UINT u_count)
 550 {
 551         SMB_OFF_T offset = (SMB_OFF_T)u_offset;
 552         SMB_OFF_T count = (SMB_OFF_T)u_count;
 553
 554         /*
 555          * For the type of system we are, attempt to
 556          * find the maximum positive lock offset as an SMB_OFF_T.
 557          */
 558
 559 #if defined(MAX_POSITIVE_LOCK_OFFSET) /* Some systems have arbitrary limits. */
 560
 561         SMB_OFF_T max_positive_lock_offset = (MAX_POSITIVE_LOCK_OFFSET);
 562
 563 #elif defined(LARGE_SMB_OFF_T) && !defined(HAVE_BROKEN_FCNTL64_LOCKS)
 564
 565         /*
 566          * In this case SMB_OFF_T is 64 bits,
 567          * and the underlying system can handle 64 bit signed locks.
 568          */
 569
 570         SMB_OFF_T mask2 = ((SMB_OFF_T)0x4) << (SMB_OFF_T_BITS-4);
 571         SMB_OFF_T mask = (mask2<<1);
 572         SMB_OFF_T max_positive_lock_offset = ~mask;
 573
 574 #else /* !LARGE_SMB_OFF_T || HAVE_BROKEN_FCNTL64_LOCKS */
 575
 576         /*
 577          * In this case either SMB_OFF_T is 32 bits,
 578          * or the underlying system cannot handle 64 bit signed locks.
 579          * All offsets & counts must be 2^31 or less.
 580          */
 581
 582         SMB_OFF_T max_positive_lock_offset = 0x7FFFFFFF;
 583
 584 #endif /* !LARGE_SMB_OFF_T || HAVE_BROKEN_FCNTL64_LOCKS */
 585
 586         /*
 587          * POSIX locks of length zero mean lock to end-of-file.
 588          * Win32 locks of length zero are point probes. Ignore
 589          * any Win32 locks of length zero. JRA.
 590          */
 591
 592         if (count == (SMB_OFF_T)0) {
 593                 DEBUG(10,("posix_lock_in_range: count = 0, ignoring.\n"));
 594                 return False;
 595         }
 596
 597         /*
 598          * If the given offset was > max_positive_lock_offset then we cannot map this at all
 599          * ignore this lock.
 600          */
 601
 602         if (u_offset & ~((SMB_BIG_UINT)max_positive_lock_offset)) {
 603                 DEBUG(10,("posix_lock_in_range: (offset = %.0f) offset > %.0f and we cannot handle this. Ignoring lock.\n",
 604                                 (double)u_offset, (double)((SMB_BIG_UINT)max_positive_lock_offset) ));
 605                 return False;
 606         }
 607
 608         /*
 609          * We must truncate the count to less than max_positive_lock_offset.
 610          */
 611
 612         if (u_count & ~((SMB_BIG_UINT)max_positive_lock_offset))
 613                 count = max_positive_lock_offset;
 614
 615         /*
 616          * Truncate count to end at max lock offset.
 617          */
 618
 619         if (offset + count < 0 || offset + count > max_positive_lock_offset)
 620                 count = max_positive_lock_offset - offset;
 621
 622         /*
 623          * If we ate all the count, ignore this lock.
 624          */
 625
 626         if (count == 0) {
 627                 DEBUG(10,("posix_lock_in_range: Count = 0. Ignoring lock u_offset = %.0f, u_count = %.0f\n",
 628                                 (double)u_offset, (double)u_count ));
 629                 return False;
 630         }
 631
 632         /*
 633          * The mapping was successful.
 634          */
 635
 636         DEBUG(10,("posix_lock_in_range: offset_out = %.0f, count_out = %.0f\n",
 637                         (double)offset, (double)count ));
 638
 639         *offset_out = offset;
 640         *count_out = count;
 641
 642         return True;
 643 }
 644
 645 /****************************************************************************
 646  Actual function that does POSIX locks. Copes with 64 -> 32 bit cruft and
 647  broken NFS implementations. Returns True if we got the lock or the region
 648  is unlocked in the F_GETLK case, False otherwise.
 649 ****************************************************************************/
 650
 651 static BOOL posix_fcntl_lock(files_struct *fsp, int op, SMB_OFF_T offset, SMB_OFF_T count, int type)
 652 {
 653         BOOL ret;
 654
 655         DEBUG(8,("posix_fcntl_lock %d %d %.0f %.0f %d\n",fsp->fh->fd,op,(double)offset,(double)count,type));
 656
 657         /* In the F_GETLK case this returns True if the region
 658            was locked, False if unlocked. */
 659
 660         ret = SMB_VFS_LOCK(fsp,fsp->fh->fd,op,offset,count,type);
 661
 662         if (!ret && ((errno == EFBIG) || (errno == ENOLCK) || (errno ==  EINVAL))) {
 663
 664                 DEBUG(0,("posix_fcntl_lock: WARNING: lock request at offset %.0f, length %.0f returned\n",
 665                                         (double)offset,(double)count));
 666                 DEBUG(0,("an %s error. This can happen when using 64 bit lock offsets\n", strerror(errno)));
 667                 DEBUG(0,("on 32 bit NFS mounted file systems.\n"));
 668
 669                 /*
 670                  * If the offset is > 0x7FFFFFFF then this will cause problems on
 671                  * 32 bit NFS mounted filesystems. Just ignore it.
 672                  */
 673
 674                 if (offset & ~((SMB_OFF_T)0x7fffffff)) {
 675                         DEBUG(0,("Offset greater than 31 bits. Returning success.\n"));
 676                         return True;
 677                 }
 678
 679                 if (count & ~((SMB_OFF_T)0x7fffffff)) {
 680                         /* 32 bit NFS file system, retry with smaller offset */
 681                         DEBUG(0,("Count greater than 31 bits - retrying with 31 bit truncated length.\n"));
 682                         errno = 0;
 683                         count &= 0x7fffffff;
 684                         ret = SMB_VFS_LOCK(fsp,fsp->fh->fd,op,offset,count,type);
 685                 }
 686         }
 687
 688         DEBUG(8,("posix_fcntl_lock: Lock call %s\n", ret ? "successful" : "failed"));
 689
 690         return ret;
 691 }
 692
 693 /****************************************************************************
 694  POSIX function to see if a file region is locked. Returns True if the
 695  region is locked, False otherwise.
 696 ****************************************************************************/
 697
 698 BOOL is_posix_locked(files_struct *fsp, SMB_BIG_UINT u_offset, SMB_BIG_UINT u_count, enum brl_type lock_type)
 699 {
 700         SMB_OFF_T offset;
 701         SMB_OFF_T count;
 702         int posix_lock_type = map_posix_lock_type(fsp,lock_type);
 703
 704         DEBUG(10,("is_posix_locked: File %s, offset = %.0f, count = %.0f, type = %s\n",
 705                         fsp->fsp_name, (double)u_offset, (double)u_count, posix_lock_type_name(lock_type) ));
 706
 707         /*
 708          * If the requested lock won't fit in the POSIX range, we will
 709          * never set it, so presume it is not locked.
 710          */
 711
 712         if(!posix_lock_in_range(&offset, &count, u_offset, u_count))
 713                 return False;
 714
 715         /*
 716          * Note that most UNIX's can *test* for a write lock on
 717          * a read-only fd, just not *set* a write lock on a read-only
 718          * fd. So we don't need to use map_lock_type here.
 719          */
 720
 721         return posix_fcntl_lock(fsp,SMB_F_GETLK,offset,count,posix_lock_type);
 722 }
 723
 724 /*
 725  * Structure used when splitting a lock range
 726  * into a POSIX lock range. Doubly linked list.
 727  */
 728
 729 struct lock_list {
 730         struct lock_list *next;
 731         struct lock_list *prev;
 732         SMB_OFF_T start;
 733         SMB_OFF_T size;
 734 };
 735
 736 /****************************************************************************
 737  Create a list of lock ranges that don't overlap a given range. Used in calculating
 738  POSIX locks and unlocks. This is a difficult function that requires ASCII art to
 739  understand it :-).
 740 ****************************************************************************/
 741
 742 static struct lock_list *posix_lock_list(TALLOC_CTX *ctx, struct lock_list *lhead, files_struct *fsp)
 743 {
 744         TDB_DATA kbuf = locking_key_fsp(fsp);
 745         TDB_DATA dbuf;
 746         struct posix_lock *locks;
 747         size_t num_locks, i;
 748
 749         dbuf.dptr = NULL;
 750
 751         dbuf = tdb_fetch(posix_lock_tdb, kbuf);
 752
 753         if (!dbuf.dptr)
 754                 return lhead;
 755
 756         locks = (struct posix_lock *)dbuf.dptr;
 757         num_locks = (size_t)(dbuf.dsize / sizeof(struct posix_lock));
 758
 759         /*
 760          * Check the current lock list on this dev/inode pair.
 761          * Quit if the list is deleted.
 762          */
 763
 764         DEBUG(10,("posix_lock_list: curr: start=%.0f,size=%.0f\n",
 765                 (double)lhead->start, (double)lhead->size ));
 766
 767         for (i=0; i<num_locks && lhead; i++) {
 768
 769                 struct posix_lock *lock = &locks[i];
 770                 struct lock_list *l_curr;
 771
 772                 /*
 773                  * Walk the lock list, checking for overlaps. Note that
 774                  * the lock list can expand within this loop if the current
 775                  * range being examined needs to be split.
 776                  */
 777
 778                 for (l_curr = lhead; l_curr;) {
 779
 780                         DEBUG(10,("posix_lock_list: lock: fd=%d: start=%.0f,size=%.0f:type=%s", lock->fd,
 781                                 (double)lock->start, (double)lock->size, posix_lock_type_name(lock->lock_type) ));
 782
 783                         if ( (l_curr->start >= (lock->start + lock->size)) ||
 784                                  (lock->start >= (l_curr->start + l_curr->size))) {
 785
 786                                 /* No overlap with this lock - leave this range alone. */
 787 /*********************************************
 788                                              +---------+
 789                                              | l_curr  |
 790                                              +---------+
 791                                 +-------+
 792                                 | lock  |
 793                                 +-------+
 794 OR....
 795              +---------+
 796              |  l_curr |
 797              +---------+
 798 **********************************************/
 799
 800                                 DEBUG(10,("no overlap case.\n" ));
 801
 802                                 l_curr = l_curr->next;
 803
 804                         } else if ( (l_curr->start >= lock->start) &&
 805                                                 (l_curr->start + l_curr->size <= lock->start + lock->size) ) {
 806
 807                                 /*
 808                                  * This unlock is completely overlapped by this existing lock range
 809                                  * and thus should have no effect (not be unlocked). Delete it from the list.
 810                                  */
 811 /*********************************************
 812                 +---------+
 813                 |  l_curr |
 814                 +---------+
 815         +---------------------------+
 816         |       lock                |
 817         +---------------------------+
 818 **********************************************/
 819                                 /* Save the next pointer */
 820                                 struct lock_list *ul_next = l_curr->next;
 821
 822                                 DEBUG(10,("delete case.\n" ));
 823
 824                                 DLIST_REMOVE(lhead, l_curr);
 825                                 if(lhead == NULL)
 826                                         break; /* No more list... */
 827
 828                                 l_curr = ul_next;
 829
 830                         } else if ( (l_curr->start >= lock->start) &&
 831                                                 (l_curr->start < lock->start + lock->size) &&
 832                                                 (l_curr->start + l_curr->size > lock->start + lock->size) ) {
 833
 834                                 /*
 835                                  * This unlock overlaps the existing lock range at the high end.
 836                                  * Truncate by moving start to existing range end and reducing size.
 837                                  */
 838 /*********************************************
 839                 +---------------+
 840                 |  l_curr       |
 841                 +---------------+
 842         +---------------+
 843         |    lock       |
 844         +---------------+
 845 BECOMES....
 846                         +-------+
 847                         | l_curr|
 848                         +-------+
 849 **********************************************/
 850
 851                                 l_curr->size = (l_curr->start + l_curr->size) - (lock->start + lock->size);
 852                                 l_curr->start = lock->start + lock->size;
 853
 854                                 DEBUG(10,("truncate high case: start=%.0f,size=%.0f\n",
 855                                                                 (double)l_curr->start, (double)l_curr->size ));
 856
 857                                 l_curr = l_curr->next;
 858
 859                         } else if ( (l_curr->start < lock->start) &&
 860                                                 (l_curr->start + l_curr->size > lock->start) &&
 861                                                 (l_curr->start + l_curr->size <= lock->start + lock->size) ) {
 862
 863                                 /*
 864                                  * This unlock overlaps the existing lock range at the low end.
 865                                  * Truncate by reducing size.
 866                                  */
 867 /*********************************************
 868    +---------------+
 869    |  l_curr       |
 870    +---------------+
 871            +---------------+
 872            |    lock       |
 873            +---------------+
 874 BECOMES....
 875    +-------+
 876    | l_curr|
 877    +-------+
 878 **********************************************/
 879
 880                                 l_curr->size = lock->start - l_curr->start;
 881
 882                                 DEBUG(10,("truncate low case: start=%.0f,size=%.0f\n",
 883                                                                 (double)l_curr->start, (double)l_curr->size ));
 884
 885                                 l_curr = l_curr->next;
 886
 887                         } else if ( (l_curr->start < lock->start) &&
 888                                                 (l_curr->start + l_curr->size > lock->start + lock->size) ) {
 889                                 /*
 890                                  * Worst case scenario. Unlock request completely overlaps an existing
 891                                  * lock range. Split the request into two, push the new (upper) request
 892                                  * into the dlink list, and continue with the entry after ul_new (as we
 893                                  * know that ul_new will not overlap with this lock).
 894                                  */
 895 /*********************************************
 896         +---------------------------+
 897         |        l_curr             |
 898         +---------------------------+
 899                 +---------+
 900                 | lock    |
 901                 +---------+
 902 BECOMES.....
 903         +-------+         +---------+
 904         | l_curr|         | l_new   |
 905         +-------+         +---------+
 906 **********************************************/
 907                                 struct lock_list *l_new = TALLOC_P(ctx, struct lock_list);
 908
 909                                 if(l_new == NULL) {
 910                                         DEBUG(0,("posix_lock_list: talloc fail.\n"));
 911                                         return NULL; /* The talloc_destroy takes care of cleanup. */
 912                                 }
 913
 914                                 ZERO_STRUCTP(l_new);
 915                                 l_new->start = lock->start + lock->size;
 916                                 l_new->size = l_curr->start + l_curr->size - l_new->start;
 917
 918                                 /* Truncate the l_curr. */
 919                                 l_curr->size = lock->start - l_curr->start;
 920
 921                                 DEBUG(10,("split case: curr: start=%.0f,size=%.0f \
 922 new: start=%.0f,size=%.0f\n", (double)l_curr->start, (double)l_curr->size,
 923                                                                 (double)l_new->start, (double)l_new->size ));
 924
 925                                 /*
 926                                  * Add into the dlink list after the l_curr point - NOT at lhead.
 927                                  * Note we can't use DLINK_ADD here as this inserts at the head of the given list.
 928                                  */
 929
 930                                 l_new->prev = l_curr;
 931                                 l_new->next = l_curr->next;
 932                                 l_curr->next = l_new;
 933
 934                                 /* And move after the link we added. */
 935                                 l_curr = l_new->next;
 936
 937                         } else {
 938
 939                                 /*
 940                                  * This logic case should never happen. Ensure this is the
 941                                  * case by forcing an abort.... Remove in production.
 942                                  */
 943                                 pstring msg;
 944
 945                                 slprintf(msg, sizeof(msg)-1, "logic flaw in cases: l_curr: start = %.0f, size = %.0f : \
 946 lock: start = %.0f, size = %.0f\n", (double)l_curr->start, (double)l_curr->size, (double)lock->start, (double)lock->size );
 947
 948                                 smb_panic(msg);
 949                         }
 950                 } /* end for ( l_curr = lhead; l_curr;) */
 951         } /* end for (i=0; i<num_locks && ul_head; i++) */
 952
 953         SAFE_FREE(dbuf.dptr);
 954
 955         return lhead;
 956 }
 957
 958 /****************************************************************************
 959  POSIX function to acquire a lock. Returns True if the
 960  lock could be granted, False if not.
 961 ****************************************************************************/
 962
 963 BOOL set_posix_lock(files_struct *fsp, SMB_BIG_UINT u_offset, SMB_BIG_UINT u_count, enum brl_type lock_type)
 964 {
 965         SMB_OFF_T offset;
 966         SMB_OFF_T count;
 967         BOOL ret = True;
 968         size_t entry_num = 0;
 969         size_t lock_count;
 970         TALLOC_CTX *l_ctx = NULL;
 971         struct lock_list *llist = NULL;
 972         struct lock_list *ll = NULL;
 973         int posix_lock_type = map_posix_lock_type(fsp,lock_type);
 974
 975         DEBUG(5,("set_posix_lock: File %s, offset = %.0f, count = %.0f, type = %s\n",
 976                         fsp->fsp_name, (double)u_offset, (double)u_count, posix_lock_type_name(lock_type) ));
 977
 978         /*
 979          * If the requested lock won't fit in the POSIX range, we will
 980          * pretend it was successful.
 981          */
 982
 983         if(!posix_lock_in_range(&offset, &count, u_offset, u_count))
 984                 return True;
 985
 986         /*
 987          * Windows is very strange. It allows read locks to be overlayed
 988          * (even over a write lock), but leaves the write lock in force until the first
 989          * unlock. It also reference counts the locks. This means the following sequence :
 990          *
 991          * process1                                      process2
 992          * ------------------------------------------------------------------------
 993          * WRITE LOCK : start = 2, len = 10
 994          *                                            READ LOCK: start =0, len = 10 - FAIL
 995          * READ LOCK : start = 0, len = 14
 996          *                                            READ LOCK: start =0, len = 10 - FAIL
 997          * UNLOCK : start = 2, len = 10
 998          *                                            READ LOCK: start =0, len = 10 - OK
 999          *
1000          * Under POSIX, the same sequence in steps 1 and 2 would not be reference counted, but
1001          * would leave a single read lock over the 0-14 region. In order to
1002          * re-create Windows semantics mapped to POSIX locks, we create multiple TDB
1003          * entries, one for each overlayed lock request. We are guarenteed by the brlock
1004          * semantics that if a write lock is added, then it will be first in the array.
1005          */
1006
1007         if ((l_ctx = talloc_init("set_posix_lock")) == NULL) {
1008                 DEBUG(0,("set_posix_lock: unable to init talloc context.\n"));
1009                 return True; /* Not a fatal error. */
1010         }
1011
1012         if ((ll = TALLOC_P(l_ctx, struct lock_list)) == NULL) {
1013                 DEBUG(0,("set_posix_lock: unable to talloc unlock list.\n"));
1014                 talloc_destroy(l_ctx);
1015                 return True; /* Not a fatal error. */
1016         }
1017
1018         /*
1019          * Create the initial list entry containing the
1020          * lock we want to add.
1021          */
1022
1023         ZERO_STRUCTP(ll);
1024         ll->start = offset;
1025         ll->size = count;
1026
1027         DLIST_ADD(llist, ll);
1028
1029         /*
1030          * The following call calculates if there are any
1031          * overlapping locks held by this process on
1032          * fd's open on the same file and splits this list
1033          * into a list of lock ranges that do not overlap with existing
1034          * POSIX locks.
1035          */
1036
1037         llist = posix_lock_list(l_ctx, llist, fsp);
1038
1039         /*
1040          * Now we have the list of ranges to lock it is safe to add the
1041          * entry into the POSIX lock tdb. We take note of the entry we
1042          * added here in case we have to remove it on POSIX lock fail.
1043          */
1044
1045         if (!add_posix_lock_entry(fsp,offset,count,posix_lock_type,&entry_num)) {
1046                 DEBUG(0,("set_posix_lock: Unable to create posix lock entry !\n"));
1047                 talloc_destroy(l_ctx);
1048                 return False;
1049         }
1050
1051         /*
1052          * Add the POSIX locks on the list of ranges returned.
1053          * As the lock is supposed to be added atomically, we need to
1054          * back out all the locks if any one of these calls fail.
1055          */
1056
1057         for (lock_count = 0, ll = llist; ll; ll = ll->next, lock_count++) {
1058                 offset = ll->start;
1059                 count = ll->size;
1060
1061                 DEBUG(5,("set_posix_lock: Real lock: Type = %s: offset = %.0f, count = %.0f\n",
1062                         posix_lock_type_name(posix_lock_type), (double)offset, (double)count ));
1063
1064                 if (!posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,posix_lock_type)) {
1065                         DEBUG(5,("set_posix_lock: Lock fail !: Type = %s: offset = %.0f, count = %.0f. Errno = %s\n",
1066                                 posix_lock_type_name(posix_lock_type), (double)offset, (double)count, strerror(errno) ));
1067                         ret = False;
1068                         break;
1069                 }
1070         }
1071
1072         if (!ret) {
1073
1074                 /*
1075                  * Back out all the POSIX locks we have on fail.
1076                  */
1077
1078                 for (ll = llist; lock_count; ll = ll->next, lock_count--) {
1079                         offset = ll->start;
1080                         count = ll->size;
1081
1082                         DEBUG(5,("set_posix_lock: Backing out locks: Type = %s: offset = %.0f, count = %.0f\n",
1083                                 posix_lock_type_name(posix_lock_type), (double)offset, (double)count ));
1084
1085                         posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,F_UNLCK);
1086                 }
1087
1088                 /*
1089                  * Remove the tdb entry for this lock.
1090                  */
1091
1092                 delete_posix_lock_entry_by_index(fsp,entry_num);
1093         }
1094
1095         talloc_destroy(l_ctx);
1096         return ret;
1097 }
1098
1099 /****************************************************************************
1100  POSIX function to release a lock. Returns True if the
1101  lock could be released, False if not.
1102 ****************************************************************************/
1103
1104 BOOL release_posix_lock(files_struct *fsp, SMB_BIG_UINT u_offset, SMB_BIG_UINT u_count)
1105 {
1106         SMB_OFF_T offset;
1107         SMB_OFF_T count;
1108         BOOL ret = True;
1109         TALLOC_CTX *ul_ctx = NULL;
1110         struct lock_list *ulist = NULL;
1111         struct lock_list *ul = NULL;
1112         struct posix_lock deleted_lock;
1113         int num_overlapped_entries;
1114
1115         DEBUG(5,("release_posix_lock: File %s, offset = %.0f, count = %.0f\n",
1116                 fsp->fsp_name, (double)u_offset, (double)u_count ));
1117
1118         /*
1119          * If the requested lock won't fit in the POSIX range, we will
1120          * pretend it was successful.
1121          */
1122
1123         if(!posix_lock_in_range(&offset, &count, u_offset, u_count))
1124                 return True;
1125
1126         /*
1127          * We treat this as one unlock request for POSIX accounting purposes even
1128          * if it may later be split into multiple smaller POSIX unlock ranges.
1129          * num_overlapped_entries is the number of existing locks that have any
1130          * overlap with this unlock request.
1131          */
1132
1133         num_overlapped_entries = delete_posix_lock_entry(fsp, offset, count, &deleted_lock);
1134
1135         if (num_overlapped_entries == -1) {
1136                 smb_panic("release_posix_lock: unable find entry to delete !\n");
1137         }
1138
1139         /*
1140          * If num_overlapped_entries is > 0, and the lock_type we just deleted from the tdb was
1141          * a POSIX write lock, then before doing the unlock we need to downgrade
1142          * the POSIX lock to a read lock. This allows any overlapping read locks
1143          * to be atomically maintained.
1144          */
1145
1146         if (num_overlapped_entries > 0 && deleted_lock.lock_type == F_WRLCK) {
1147                 if (!posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,F_RDLCK)) {
1148                         DEBUG(0,("release_posix_lock: downgrade of lock failed with error %s !\n", strerror(errno) ));
1149                         return False;
1150                 }
1151         }
1152
1153         if ((ul_ctx = talloc_init("release_posix_lock")) == NULL) {
1154                 DEBUG(0,("release_posix_lock: unable to init talloc context.\n"));
1155                 return True; /* Not a fatal error. */
1156         }
1157
1158         if ((ul = TALLOC_P(ul_ctx, struct lock_list)) == NULL) {
1159                 DEBUG(0,("release_posix_lock: unable to talloc unlock list.\n"));
1160                 talloc_destroy(ul_ctx);
1161                 return True; /* Not a fatal error. */
1162         }
1163
1164         /*
1165          * Create the initial list entry containing the
1166          * lock we want to remove.
1167          */
1168
1169         ZERO_STRUCTP(ul);
1170         ul->start = offset;
1171         ul->size = count;
1172
1173         DLIST_ADD(ulist, ul);
1174
1175         /*
1176          * The following call calculates if there are any
1177          * overlapping locks held by this process on
1178          * fd's open on the same file and creates a
1179          * list of unlock ranges that will allow
1180          * POSIX lock ranges to remain on the file whilst the
1181          * unlocks are performed.
1182          */
1183
1184         ulist = posix_lock_list(ul_ctx, ulist, fsp);
1185
1186         /*
1187          * Release the POSIX locks on the list of ranges returned.
1188          */
1189
1190         for(; ulist; ulist = ulist->next) {
1191                 offset = ulist->start;
1192                 count = ulist->size;
1193
1194                 DEBUG(5,("release_posix_lock: Real unlock: offset = %.0f, count = %.0f\n",
1195                         (double)offset, (double)count ));
1196
1197                 if (!posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,F_UNLCK))
1198                         ret = False;
1199         }
1200
1201         talloc_destroy(ul_ctx);
1202
1203         return ret;
1204 }
1205
1206 /****************************************************************************
1207  Remove all lock entries for a specific dev/inode pair from the tdb.
1208 ****************************************************************************/
1209
1210 static void delete_posix_lock_entries(files_struct *fsp)
1211 {
1212         TDB_DATA kbuf = locking_key_fsp(fsp);
1213
1214         if (tdb_delete(posix_lock_tdb, kbuf) == -1)
1215                 DEBUG(0,("delete_close_entries: tdb_delete fail !\n"));
1216 }
1217
1218 /****************************************************************************
1219  Debug function.
1220 ****************************************************************************/
1221
1222 static void dump_entry(struct posix_lock *pl)
1223 {
1224         DEBUG(10,("entry: start=%.0f, size=%.0f, type=%d, fd=%i\n",
1225                 (double)pl->start, (double)pl->size, (int)pl->lock_type, pl->fd ));
1226 }
1227
1228 /****************************************************************************
1229  Remove any locks on this fd. Called from file_close().
1230 ****************************************************************************/
1231
1232 void posix_locking_close_file(files_struct *fsp)
1233 {
1234         struct posix_lock *entries = NULL;
1235         size_t count, i;
1236
1237         /*
1238          * Optimization for the common case where we are the only
1239          * opener of a file. If all fd entries are our own, we don't
1240          * need to explicitly release all the locks via the POSIX functions,
1241          * we can just remove all the entries in the tdb and allow the
1242          * close to remove the real locks.
1243          */
1244
1245         count = get_posix_lock_entries(fsp, &entries);
1246
1247         if (count == 0) {
1248                 DEBUG(10,("posix_locking_close_file: file %s has no outstanding locks.\n", fsp->fsp_name ));
1249                 return;
1250         }
1251
1252         for (i = 0; i < count; i++) {
1253                 if (entries[i].fd != fsp->fh->fd )
1254                         break;
1255
1256                 dump_entry(&entries[i]);
1257         }
1258
1259         if (i == count) {
1260                 /* All locks are ours. */
1261                 DEBUG(10,("posix_locking_close_file: file %s has %u outstanding locks, but all on one fd.\n",
1262                         fsp->fsp_name, (unsigned int)count ));
1263                 SAFE_FREE(entries);
1264                 delete_posix_lock_entries(fsp);
1265                 return;
1266         }
1267
1268         /*
1269          * Difficult case. We need to delete all our locks, whilst leaving
1270          * all other POSIX locks in place.
1271          */
1272
1273         for (i = 0; i < count; i++) {
1274                 struct posix_lock *pl = &entries[i];
1275                 if (pl->fd == fsp->fh->fd)
1276                         release_posix_lock(fsp, (SMB_BIG_UINT)pl->start, (SMB_BIG_UINT)pl->size );
1277         }
1278         SAFE_FREE(entries);
1279 }
1280
1281 /*******************************************************************
1282  Create the in-memory POSIX lock databases.
1283 ********************************************************************/
1284
1285 BOOL posix_locking_init(int read_only)
1286 {
1287         if (posix_lock_tdb && posix_pending_close_tdb)
1288                 return True;
1289
1290         if (!posix_lock_tdb)
1291                 posix_lock_tdb = tdb_open_log(NULL, 0, TDB_INTERNAL,
1292                                           read_only?O_RDONLY:(O_RDWR|O_CREAT), 0644);
1293         if (!posix_lock_tdb) {
1294                 DEBUG(0,("Failed to open POSIX byte range locking database.\n"));
1295                 return False;
1296         }
1297         if (!posix_pending_close_tdb)
1298                 posix_pending_close_tdb = tdb_open_log(NULL, 0, TDB_INTERNAL,
1299                                                    read_only?O_RDONLY:(O_RDWR|O_CREAT), 0644);
1300         if (!posix_pending_close_tdb) {
1301                 DEBUG(0,("Failed to open POSIX pending close database.\n"));
1302                 return False;
1303         }
1304
1305         return True;
1306 }
1307
1308 /*******************************************************************
1309  Delete the in-memory POSIX lock databases.
1310 ********************************************************************/
1311
1312 BOOL posix_locking_end(void)
1313 {
1314     if (posix_lock_tdb && tdb_close(posix_lock_tdb) != 0)
1315                 return False;
1316     if (posix_pending_close_tdb && tdb_close(posix_pending_close_tdb) != 0)
1317                 return False;
1318         return True;
1319 }