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.
 648 ****************************************************************************/
 649
 650 static BOOL posix_fcntl_lock(files_struct *fsp, int op, SMB_OFF_T offset, SMB_OFF_T count, int type)
 651 {
 652         int ret;
 653
 654         DEBUG(8,("posix_fcntl_lock %d %d %.0f %.0f %d\n",fsp->fh->fd,op,(double)offset,(double)count,type));
 655
 656         ret = SMB_VFS_LOCK(fsp,fsp->fh->fd,op,offset,count,type);
 657
 658         if (!ret && ((errno == EFBIG) || (errno == ENOLCK) || (errno ==  EINVAL))) {
 659
 660                 DEBUG(0,("posix_fcntl_lock: WARNING: lock request at offset %.0f, length %.0f returned\n",
 661                                         (double)offset,(double)count));
 662                 DEBUG(0,("an %s error. This can happen when using 64 bit lock offsets\n", strerror(errno)));
 663                 DEBUG(0,("on 32 bit NFS mounted file systems.\n"));
 664
 665                 /*
 666                  * If the offset is > 0x7FFFFFFF then this will cause problems on
 667                  * 32 bit NFS mounted filesystems. Just ignore it.
 668                  */
 669
 670                 if (offset & ~((SMB_OFF_T)0x7fffffff)) {
 671                         DEBUG(0,("Offset greater than 31 bits. Returning success.\n"));
 672                         return True;
 673                 }
 674
 675                 if (count & ~((SMB_OFF_T)0x7fffffff)) {
 676                         /* 32 bit NFS file system, retry with smaller offset */
 677                         DEBUG(0,("Count greater than 31 bits - retrying with 31 bit truncated length.\n"));
 678                         errno = 0;
 679                         count &= 0x7fffffff;
 680                         ret = SMB_VFS_LOCK(fsp,fsp->fh->fd,op,offset,count,type);
 681                 }
 682         }
 683
 684         DEBUG(8,("posix_fcntl_lock: Lock call %s\n", ret ? "successful" : "failed"));
 685
 686         return ret;
 687 }
 688
 689 /****************************************************************************
 690  POSIX function to see if a file region is locked. Returns True if the
 691  region is locked, False otherwise.
 692 ****************************************************************************/
 693
 694 BOOL is_posix_locked(files_struct *fsp, SMB_BIG_UINT u_offset, SMB_BIG_UINT u_count, enum brl_type lock_type)
 695 {
 696         SMB_OFF_T offset;
 697         SMB_OFF_T count;
 698         int posix_lock_type = map_posix_lock_type(fsp,lock_type);
 699
 700         DEBUG(10,("is_posix_locked: File %s, offset = %.0f, count = %.0f, type = %s\n",
 701                         fsp->fsp_name, (double)u_offset, (double)u_count, posix_lock_type_name(lock_type) ));
 702
 703         /*
 704          * If the requested lock won't fit in the POSIX range, we will
 705          * never set it, so presume it is not locked.
 706          */
 707
 708         if(!posix_lock_in_range(&offset, &count, u_offset, u_count))
 709                 return False;
 710
 711         /*
 712          * Note that most UNIX's can *test* for a write lock on
 713          * a read-only fd, just not *set* a write lock on a read-only
 714          * fd. So we don't need to use map_lock_type here.
 715          */
 716
 717         return posix_fcntl_lock(fsp,SMB_F_GETLK,offset,count,posix_lock_type);
 718 }
 719
 720 /*
 721  * Structure used when splitting a lock range
 722  * into a POSIX lock range. Doubly linked list.
 723  */
 724
 725 struct lock_list {
 726         struct lock_list *next;
 727         struct lock_list *prev;
 728         SMB_OFF_T start;
 729         SMB_OFF_T size;
 730 };
 731
 732 /****************************************************************************
 733  Create a list of lock ranges that don't overlap a given range. Used in calculating
 734  POSIX locks and unlocks. This is a difficult function that requires ASCII art to
 735  understand it :-).
 736 ****************************************************************************/
 737
 738 static struct lock_list *posix_lock_list(TALLOC_CTX *ctx, struct lock_list *lhead, files_struct *fsp)
 739 {
 740         TDB_DATA kbuf = locking_key_fsp(fsp);
 741         TDB_DATA dbuf;
 742         struct posix_lock *locks;
 743         size_t num_locks, i;
 744
 745         dbuf.dptr = NULL;
 746
 747         dbuf = tdb_fetch(posix_lock_tdb, kbuf);
 748
 749         if (!dbuf.dptr)
 750                 return lhead;
 751
 752         locks = (struct posix_lock *)dbuf.dptr;
 753         num_locks = (size_t)(dbuf.dsize / sizeof(struct posix_lock));
 754
 755         /*
 756          * Check the current lock list on this dev/inode pair.
 757          * Quit if the list is deleted.
 758          */
 759
 760         DEBUG(10,("posix_lock_list: curr: start=%.0f,size=%.0f\n",
 761                 (double)lhead->start, (double)lhead->size ));
 762
 763         for (i=0; i<num_locks && lhead; i++) {
 764
 765                 struct posix_lock *lock = &locks[i];
 766                 struct lock_list *l_curr;
 767
 768                 /*
 769                  * Walk the lock list, checking for overlaps. Note that
 770                  * the lock list can expand within this loop if the current
 771                  * range being examined needs to be split.
 772                  */
 773
 774                 for (l_curr = lhead; l_curr;) {
 775
 776                         DEBUG(10,("posix_lock_list: lock: fd=%d: start=%.0f,size=%.0f:type=%s", lock->fd,
 777                                 (double)lock->start, (double)lock->size, posix_lock_type_name(lock->lock_type) ));
 778
 779                         if ( (l_curr->start >= (lock->start + lock->size)) ||
 780                                  (lock->start >= (l_curr->start + l_curr->size))) {
 781
 782                                 /* No overlap with this lock - leave this range alone. */
 783 /*********************************************
 784                                              +---------+
 785                                              | l_curr  |
 786                                              +---------+
 787                                 +-------+
 788                                 | lock  |
 789                                 +-------+
 790 OR....
 791              +---------+
 792              |  l_curr |
 793              +---------+
 794 **********************************************/
 795
 796                                 DEBUG(10,("no overlap case.\n" ));
 797
 798                                 l_curr = l_curr->next;
 799
 800                         } else if ( (l_curr->start >= lock->start) &&
 801                                                 (l_curr->start + l_curr->size <= lock->start + lock->size) ) {
 802
 803                                 /*
 804                                  * This unlock is completely overlapped by this existing lock range
 805                                  * and thus should have no effect (not be unlocked). Delete it from the list.
 806                                  */
 807 /*********************************************
 808                 +---------+
 809                 |  l_curr |
 810                 +---------+
 811         +---------------------------+
 812         |       lock                |
 813         +---------------------------+
 814 **********************************************/
 815                                 /* Save the next pointer */
 816                                 struct lock_list *ul_next = l_curr->next;
 817
 818                                 DEBUG(10,("delete case.\n" ));
 819
 820                                 DLIST_REMOVE(lhead, l_curr);
 821                                 if(lhead == NULL)
 822                                         break; /* No more list... */
 823
 824                                 l_curr = ul_next;
 825
 826                         } else if ( (l_curr->start >= lock->start) &&
 827                                                 (l_curr->start < lock->start + lock->size) &&
 828                                                 (l_curr->start + l_curr->size > lock->start + lock->size) ) {
 829
 830                                 /*
 831                                  * This unlock overlaps the existing lock range at the high end.
 832                                  * Truncate by moving start to existing range end and reducing size.
 833                                  */
 834 /*********************************************
 835                 +---------------+
 836                 |  l_curr       |
 837                 +---------------+
 838         +---------------+
 839         |    lock       |
 840         +---------------+
 841 BECOMES....
 842                         +-------+
 843                         | l_curr|
 844                         +-------+
 845 **********************************************/
 846
 847                                 l_curr->size = (l_curr->start + l_curr->size) - (lock->start + lock->size);
 848                                 l_curr->start = lock->start + lock->size;
 849
 850                                 DEBUG(10,("truncate high case: start=%.0f,size=%.0f\n",
 851                                                                 (double)l_curr->start, (double)l_curr->size ));
 852
 853                                 l_curr = l_curr->next;
 854
 855                         } else if ( (l_curr->start < lock->start) &&
 856                                                 (l_curr->start + l_curr->size > lock->start) &&
 857                                                 (l_curr->start + l_curr->size <= lock->start + lock->size) ) {
 858
 859                                 /*
 860                                  * This unlock overlaps the existing lock range at the low end.
 861                                  * Truncate by reducing size.
 862                                  */
 863 /*********************************************
 864    +---------------+
 865    |  l_curr       |
 866    +---------------+
 867            +---------------+
 868            |    lock       |
 869            +---------------+
 870 BECOMES....
 871    +-------+
 872    | l_curr|
 873    +-------+
 874 **********************************************/
 875
 876                                 l_curr->size = lock->start - l_curr->start;
 877
 878                                 DEBUG(10,("truncate low case: start=%.0f,size=%.0f\n",
 879                                                                 (double)l_curr->start, (double)l_curr->size ));
 880
 881                                 l_curr = l_curr->next;
 882
 883                         } else if ( (l_curr->start < lock->start) &&
 884                                                 (l_curr->start + l_curr->size > lock->start + lock->size) ) {
 885                                 /*
 886                                  * Worst case scenario. Unlock request completely overlaps an existing
 887                                  * lock range. Split the request into two, push the new (upper) request
 888                                  * into the dlink list, and continue with the entry after ul_new (as we
 889                                  * know that ul_new will not overlap with this lock).
 890                                  */
 891 /*********************************************
 892         +---------------------------+
 893         |        l_curr             |
 894         +---------------------------+
 895                 +---------+
 896                 | lock    |
 897                 +---------+
 898 BECOMES.....
 899         +-------+         +---------+
 900         | l_curr|         | l_new   |
 901         +-------+         +---------+
 902 **********************************************/
 903                                 struct lock_list *l_new = TALLOC_P(ctx, struct lock_list);
 904
 905                                 if(l_new == NULL) {
 906                                         DEBUG(0,("posix_lock_list: talloc fail.\n"));
 907                                         return NULL; /* The talloc_destroy takes care of cleanup. */
 908                                 }
 909
 910                                 ZERO_STRUCTP(l_new);
 911                                 l_new->start = lock->start + lock->size;
 912                                 l_new->size = l_curr->start + l_curr->size - l_new->start;
 913
 914                                 /* Truncate the l_curr. */
 915                                 l_curr->size = lock->start - l_curr->start;
 916
 917                                 DEBUG(10,("split case: curr: start=%.0f,size=%.0f \
 918 new: start=%.0f,size=%.0f\n", (double)l_curr->start, (double)l_curr->size,
 919                                                                 (double)l_new->start, (double)l_new->size ));
 920
 921                                 /*
 922                                  * Add into the dlink list after the l_curr point - NOT at lhead.
 923                                  * Note we can't use DLINK_ADD here as this inserts at the head of the given list.
 924                                  */
 925
 926                                 l_new->prev = l_curr;
 927                                 l_new->next = l_curr->next;
 928                                 l_curr->next = l_new;
 929
 930                                 /* And move after the link we added. */
 931                                 l_curr = l_new->next;
 932
 933                         } else {
 934
 935                                 /*
 936                                  * This logic case should never happen. Ensure this is the
 937                                  * case by forcing an abort.... Remove in production.
 938                                  */
 939                                 pstring msg;
 940
 941                                 slprintf(msg, sizeof(msg)-1, "logic flaw in cases: l_curr: start = %.0f, size = %.0f : \
 942 lock: start = %.0f, size = %.0f\n", (double)l_curr->start, (double)l_curr->size, (double)lock->start, (double)lock->size );
 943
 944                                 smb_panic(msg);
 945                         }
 946                 } /* end for ( l_curr = lhead; l_curr;) */
 947         } /* end for (i=0; i<num_locks && ul_head; i++) */
 948
 949         SAFE_FREE(dbuf.dptr);
 950
 951         return lhead;
 952 }
 953
 954 /****************************************************************************
 955  POSIX function to acquire a lock. Returns True if the
 956  lock could be granted, False if not.
 957 ****************************************************************************/
 958
 959 BOOL set_posix_lock(files_struct *fsp, SMB_BIG_UINT u_offset, SMB_BIG_UINT u_count, enum brl_type lock_type)
 960 {
 961         SMB_OFF_T offset;
 962         SMB_OFF_T count;
 963         BOOL ret = True;
 964         size_t entry_num = 0;
 965         size_t lock_count;
 966         TALLOC_CTX *l_ctx = NULL;
 967         struct lock_list *llist = NULL;
 968         struct lock_list *ll = NULL;
 969         int posix_lock_type = map_posix_lock_type(fsp,lock_type);
 970
 971         DEBUG(5,("set_posix_lock: File %s, offset = %.0f, count = %.0f, type = %s\n",
 972                         fsp->fsp_name, (double)u_offset, (double)u_count, posix_lock_type_name(lock_type) ));
 973
 974         /*
 975          * If the requested lock won't fit in the POSIX range, we will
 976          * pretend it was successful.
 977          */
 978
 979         if(!posix_lock_in_range(&offset, &count, u_offset, u_count))
 980                 return True;
 981
 982         /*
 983          * Windows is very strange. It allows read locks to be overlayed
 984          * (even over a write lock), but leaves the write lock in force until the first
 985          * unlock. It also reference counts the locks. This means the following sequence :
 986          *
 987          * process1                                      process2
 988          * ------------------------------------------------------------------------
 989          * WRITE LOCK : start = 2, len = 10
 990          *                                            READ LOCK: start =0, len = 10 - FAIL
 991          * READ LOCK : start = 0, len = 14
 992          *                                            READ LOCK: start =0, len = 10 - FAIL
 993          * UNLOCK : start = 2, len = 10
 994          *                                            READ LOCK: start =0, len = 10 - OK
 995          *
 996          * Under POSIX, the same sequence in steps 1 and 2 would not be reference counted, but
 997          * would leave a single read lock over the 0-14 region. In order to
 998          * re-create Windows semantics mapped to POSIX locks, we create multiple TDB
 999          * entries, one for each overlayed lock request. We are guarenteed by the brlock
1000          * semantics that if a write lock is added, then it will be first in the array.
1001          */
1002
1003         if ((l_ctx = talloc_init("set_posix_lock")) == NULL) {
1004                 DEBUG(0,("set_posix_lock: unable to init talloc context.\n"));
1005                 return True; /* Not a fatal error. */
1006         }
1007
1008         if ((ll = TALLOC_P(l_ctx, struct lock_list)) == NULL) {
1009                 DEBUG(0,("set_posix_lock: unable to talloc unlock list.\n"));
1010                 talloc_destroy(l_ctx);
1011                 return True; /* Not a fatal error. */
1012         }
1013
1014         /*
1015          * Create the initial list entry containing the
1016          * lock we want to add.
1017          */
1018
1019         ZERO_STRUCTP(ll);
1020         ll->start = offset;
1021         ll->size = count;
1022
1023         DLIST_ADD(llist, ll);
1024
1025         /*
1026          * The following call calculates if there are any
1027          * overlapping locks held by this process on
1028          * fd's open on the same file and splits this list
1029          * into a list of lock ranges that do not overlap with existing
1030          * POSIX locks.
1031          */
1032
1033         llist = posix_lock_list(l_ctx, llist, fsp);
1034
1035         /*
1036          * Now we have the list of ranges to lock it is safe to add the
1037          * entry into the POSIX lock tdb. We take note of the entry we
1038          * added here in case we have to remove it on POSIX lock fail.
1039          */
1040
1041         if (!add_posix_lock_entry(fsp,offset,count,posix_lock_type,&entry_num)) {
1042                 DEBUG(0,("set_posix_lock: Unable to create posix lock entry !\n"));
1043                 talloc_destroy(l_ctx);
1044                 return False;
1045         }
1046
1047         /*
1048          * Add the POSIX locks on the list of ranges returned.
1049          * As the lock is supposed to be added atomically, we need to
1050          * back out all the locks if any one of these calls fail.
1051          */
1052
1053         for (lock_count = 0, ll = llist; ll; ll = ll->next, lock_count++) {
1054                 offset = ll->start;
1055                 count = ll->size;
1056
1057                 DEBUG(5,("set_posix_lock: Real lock: Type = %s: offset = %.0f, count = %.0f\n",
1058                         posix_lock_type_name(posix_lock_type), (double)offset, (double)count ));
1059
1060                 if (!posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,posix_lock_type)) {
1061                         DEBUG(5,("set_posix_lock: Lock fail !: Type = %s: offset = %.0f, count = %.0f. Errno = %s\n",
1062                                 posix_lock_type_name(posix_lock_type), (double)offset, (double)count, strerror(errno) ));
1063                         ret = False;
1064                         break;
1065                 }
1066         }
1067
1068         if (!ret) {
1069
1070                 /*
1071                  * Back out all the POSIX locks we have on fail.
1072                  */
1073
1074                 for (ll = llist; lock_count; ll = ll->next, lock_count--) {
1075                         offset = ll->start;
1076                         count = ll->size;
1077
1078                         DEBUG(5,("set_posix_lock: Backing out locks: Type = %s: offset = %.0f, count = %.0f\n",
1079                                 posix_lock_type_name(posix_lock_type), (double)offset, (double)count ));
1080
1081                         posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,F_UNLCK);
1082                 }
1083
1084                 /*
1085                  * Remove the tdb entry for this lock.
1086                  */
1087
1088                 delete_posix_lock_entry_by_index(fsp,entry_num);
1089         }
1090
1091         talloc_destroy(l_ctx);
1092         return ret;
1093 }
1094
1095 /****************************************************************************
1096  POSIX function to release a lock. Returns True if the
1097  lock could be released, False if not.
1098 ****************************************************************************/
1099
1100 BOOL release_posix_lock(files_struct *fsp, SMB_BIG_UINT u_offset, SMB_BIG_UINT u_count)
1101 {
1102         SMB_OFF_T offset;
1103         SMB_OFF_T count;
1104         BOOL ret = True;
1105         TALLOC_CTX *ul_ctx = NULL;
1106         struct lock_list *ulist = NULL;
1107         struct lock_list *ul = NULL;
1108         struct posix_lock deleted_lock;
1109         int num_overlapped_entries;
1110
1111         DEBUG(5,("release_posix_lock: File %s, offset = %.0f, count = %.0f\n",
1112                 fsp->fsp_name, (double)u_offset, (double)u_count ));
1113
1114         /*
1115          * If the requested lock won't fit in the POSIX range, we will
1116          * pretend it was successful.
1117          */
1118
1119         if(!posix_lock_in_range(&offset, &count, u_offset, u_count))
1120                 return True;
1121
1122         /*
1123          * We treat this as one unlock request for POSIX accounting purposes even
1124          * if it may later be split into multiple smaller POSIX unlock ranges.
1125          * num_overlapped_entries is the number of existing locks that have any
1126          * overlap with this unlock request.
1127          */
1128
1129         num_overlapped_entries = delete_posix_lock_entry(fsp, offset, count, &deleted_lock);
1130
1131         if (num_overlapped_entries == -1) {
1132                 smb_panic("release_posix_lock: unable find entry to delete !\n");
1133         }
1134
1135         /*
1136          * If num_overlapped_entries is > 0, and the lock_type we just deleted from the tdb was
1137          * a POSIX write lock, then before doing the unlock we need to downgrade
1138          * the POSIX lock to a read lock. This allows any overlapping read locks
1139          * to be atomically maintained.
1140          */
1141
1142         if (num_overlapped_entries > 0 && deleted_lock.lock_type == F_WRLCK) {
1143                 if (!posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,F_RDLCK)) {
1144                         DEBUG(0,("release_posix_lock: downgrade of lock failed with error %s !\n", strerror(errno) ));
1145                         return False;
1146                 }
1147         }
1148
1149         if ((ul_ctx = talloc_init("release_posix_lock")) == NULL) {
1150                 DEBUG(0,("release_posix_lock: unable to init talloc context.\n"));
1151                 return True; /* Not a fatal error. */
1152         }
1153
1154         if ((ul = TALLOC_P(ul_ctx, struct lock_list)) == NULL) {
1155                 DEBUG(0,("release_posix_lock: unable to talloc unlock list.\n"));
1156                 talloc_destroy(ul_ctx);
1157                 return True; /* Not a fatal error. */
1158         }
1159
1160         /*
1161          * Create the initial list entry containing the
1162          * lock we want to remove.
1163          */
1164
1165         ZERO_STRUCTP(ul);
1166         ul->start = offset;
1167         ul->size = count;
1168
1169         DLIST_ADD(ulist, ul);
1170
1171         /*
1172          * The following call calculates if there are any
1173          * overlapping locks held by this process on
1174          * fd's open on the same file and creates a
1175          * list of unlock ranges that will allow
1176          * POSIX lock ranges to remain on the file whilst the
1177          * unlocks are performed.
1178          */
1179
1180         ulist = posix_lock_list(ul_ctx, ulist, fsp);
1181
1182         /*
1183          * Release the POSIX locks on the list of ranges returned.
1184          */
1185
1186         for(; ulist; ulist = ulist->next) {
1187                 offset = ulist->start;
1188                 count = ulist->size;
1189
1190                 DEBUG(5,("release_posix_lock: Real unlock: offset = %.0f, count = %.0f\n",
1191                         (double)offset, (double)count ));
1192
1193                 if (!posix_fcntl_lock(fsp,SMB_F_SETLK,offset,count,F_UNLCK))
1194                         ret = False;
1195         }
1196
1197         talloc_destroy(ul_ctx);
1198
1199         return ret;
1200 }
1201
1202 /****************************************************************************
1203  Remove all lock entries for a specific dev/inode pair from the tdb.
1204 ****************************************************************************/
1205
1206 static void delete_posix_lock_entries(files_struct *fsp)
1207 {
1208         TDB_DATA kbuf = locking_key_fsp(fsp);
1209
1210         if (tdb_delete(posix_lock_tdb, kbuf) == -1)
1211                 DEBUG(0,("delete_close_entries: tdb_delete fail !\n"));
1212 }
1213
1214 /****************************************************************************
1215  Debug function.
1216 ****************************************************************************/
1217
1218 static void dump_entry(struct posix_lock *pl)
1219 {
1220         DEBUG(10,("entry: start=%.0f, size=%.0f, type=%d, fd=%i\n",
1221                 (double)pl->start, (double)pl->size, (int)pl->lock_type, pl->fd ));
1222 }
1223
1224 /****************************************************************************
1225  Remove any locks on this fd. Called from file_close().
1226 ****************************************************************************/
1227
1228 void posix_locking_close_file(files_struct *fsp)
1229 {
1230         struct posix_lock *entries = NULL;
1231         size_t count, i;
1232
1233         /*
1234          * Optimization for the common case where we are the only
1235          * opener of a file. If all fd entries are our own, we don't
1236          * need to explicitly release all the locks via the POSIX functions,
1237          * we can just remove all the entries in the tdb and allow the
1238          * close to remove the real locks.
1239          */
1240
1241         count = get_posix_lock_entries(fsp, &entries);
1242
1243         if (count == 0) {
1244                 DEBUG(10,("posix_locking_close_file: file %s has no outstanding locks.\n", fsp->fsp_name ));
1245                 return;
1246         }
1247
1248         for (i = 0; i < count; i++) {
1249                 if (entries[i].fd != fsp->fh->fd )
1250                         break;
1251
1252                 dump_entry(&entries[i]);
1253         }
1254
1255         if (i == count) {
1256                 /* All locks are ours. */
1257                 DEBUG(10,("posix_locking_close_file: file %s has %u outstanding locks, but all on one fd.\n",
1258                         fsp->fsp_name, (unsigned int)count ));
1259                 SAFE_FREE(entries);
1260                 delete_posix_lock_entries(fsp);
1261                 return;
1262         }
1263
1264         /*
1265          * Difficult case. We need to delete all our locks, whilst leaving
1266          * all other POSIX locks in place.
1267          */
1268
1269         for (i = 0; i < count; i++) {
1270                 struct posix_lock *pl = &entries[i];
1271                 if (pl->fd == fsp->fh->fd)
1272                         release_posix_lock(fsp, (SMB_BIG_UINT)pl->start, (SMB_BIG_UINT)pl->size );
1273         }
1274         SAFE_FREE(entries);
1275 }
1276
1277 /*******************************************************************
1278  Create the in-memory POSIX lock databases.
1279 ********************************************************************/
1280
1281 BOOL posix_locking_init(int read_only)
1282 {
1283         if (posix_lock_tdb && posix_pending_close_tdb)
1284                 return True;
1285
1286         if (!posix_lock_tdb)
1287                 posix_lock_tdb = tdb_open_log(NULL, 0, TDB_INTERNAL,
1288                                           read_only?O_RDONLY:(O_RDWR|O_CREAT), 0644);
1289         if (!posix_lock_tdb) {
1290                 DEBUG(0,("Failed to open POSIX byte range locking database.\n"));
1291                 return False;
1292         }
1293         if (!posix_pending_close_tdb)
1294                 posix_pending_close_tdb = tdb_open_log(NULL, 0, TDB_INTERNAL,
1295                                                    read_only?O_RDONLY:(O_RDWR|O_CREAT), 0644);
1296         if (!posix_pending_close_tdb) {
1297                 DEBUG(0,("Failed to open POSIX pending close database.\n"));
1298                 return False;
1299         }
1300
1301         return True;
1302 }
1303
1304 /*******************************************************************
1305  Delete the in-memory POSIX lock databases.
1306 ********************************************************************/
1307
1308 BOOL posix_locking_end(void)
1309 {
1310     if (posix_lock_tdb && tdb_close(posix_lock_tdb) != 0)
1311                 return False;
1312     if (posix_pending_close_tdb && tdb_close(posix_pending_close_tdb) != 0)
1313                 return False;
1314         return True;
1315 }