source3/locking/locking.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Locking functions
   4    Copyright (C) Andrew Tridgell 1992-2000
   5    Copyright (C) Jeremy Allison 1992-2000
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20
  21    Revision History:
  22
  23    12 aug 96: Erik.Devriendt@te6.siemens.be
  24    added support for shared memory implementation of share mode locking
  25
  26    May 1997. Jeremy Allison (jallison@whistle.com). Modified share mode
  27    locking to deal with multiple share modes per open file.
  28
  29    September 1997. Jeremy Allison (jallison@whistle.com). Added oplock
  30    support.
  31
  32    rewrtten completely to use new tdb code. Tridge, Dec '99
  33
  34    Added POSIX locking support. Jeremy Allison (jeremy@valinux.com), Apr. 2000.
  35 */
  36
  37 #include "includes.h"
  38 uint16 global_smbpid;
  39
  40 /* the locking database handle */
  41 static TDB_CONTEXT *tdb;
  42
  43 /****************************************************************************
  44  Debugging aid :-).
  45 ****************************************************************************/
  46
  47 static const char *lock_type_name(enum brl_type lock_type)
  48 {
  49         return (lock_type == READ_LOCK) ? "READ" : "WRITE";
  50 }
  51
  52 /****************************************************************************
  53  Utility function called to see if a file region is locked.
  54  If check_self is True, then checks on our own fd with the same locking context
  55  are still made. If check_self is False, then checks are not made on our own fd
  56  with the same locking context are not made.
  57 ****************************************************************************/
  58
  59 BOOL is_locked(files_struct *fsp,connection_struct *conn,
  60                SMB_BIG_UINT count,SMB_BIG_UINT offset,
  61                enum brl_type lock_type, BOOL check_self)
  62 {
  63         int snum = SNUM(conn);
  64         BOOL ret;
  65
  66         if (count == 0)
  67                 return(False);
  68
  69         if (!lp_locking(snum) || !lp_strict_locking(snum))
  70                 return(False);
  71
  72         ret = !brl_locktest(fsp->dev, fsp->inode, fsp->fnum,
  73                              global_smbpid, sys_getpid(), conn->cnum,
  74                              offset, count, lock_type, check_self);
  75
  76         DEBUG(10,("is_locked: brl start=%.0f len=%.0f %s for file %s\n",
  77                         (double)offset, (double)count, ret ? "locked" : "unlocked",
  78                         fsp->fsp_name ));
  79
  80         /*
  81          * There is no lock held by an SMB daemon, check to
  82          * see if there is a POSIX lock from a UNIX or NFS process.
  83          */
  84
  85         if(!ret && lp_posix_locking(snum)) {
  86                 ret = is_posix_locked(fsp, offset, count, lock_type);
  87
  88                 DEBUG(10,("is_locked: posix start=%.0f len=%.0f %s for file %s\n",
  89                                 (double)offset, (double)count, ret ? "locked" : "unlocked",
  90                                 fsp->fsp_name ));
  91         }
  92
  93         return ret;
  94 }
  95
  96 /****************************************************************************
  97  Utility function called by locking requests.
  98 ****************************************************************************/
  99
 100 static NTSTATUS do_lock(files_struct *fsp,connection_struct *conn, uint16 lock_pid,
 101                  SMB_BIG_UINT count,SMB_BIG_UINT offset,enum brl_type lock_type, BOOL *my_lock_ctx)
 102 {
 103         NTSTATUS status = NT_STATUS_LOCK_NOT_GRANTED;
 104
 105         if (!lp_locking(SNUM(conn)))
 106                 return NT_STATUS_OK;
 107
 108         /* NOTE! 0 byte long ranges ARE allowed and should be stored  */
 109
 110         DEBUG(10,("do_lock: lock type %s start=%.0f len=%.0f requested for file %s\n",
 111                   lock_type_name(lock_type), (double)offset, (double)count, fsp->fsp_name ));
 112
 113         if (OPEN_FSP(fsp) && fsp->can_lock && (fsp->conn == conn)) {
 114                 status = brl_lock(fsp->dev, fsp->inode, fsp->fnum,
 115                                   lock_pid, sys_getpid(), conn->cnum,
 116                                   offset, count,
 117                                   lock_type, my_lock_ctx);
 118
 119                 if (NT_STATUS_IS_OK(status) && lp_posix_locking(SNUM(conn))) {
 120
 121                         /*
 122                          * Try and get a POSIX lock on this range.
 123                          * Note that this is ok if it is a read lock
 124                          * overlapping on a different fd. JRA.
 125                          */
 126
 127                         if (!set_posix_lock(fsp, offset, count, lock_type)) {
 128                                 if (errno == EACCES || errno == EAGAIN)
 129                                         status = NT_STATUS_FILE_LOCK_CONFLICT;
 130                                 else
 131                                         status = map_nt_error_from_unix(errno);
 132
 133                                 /*
 134                                  * We failed to map - we must now remove the brl
 135                                  * lock entry.
 136                                  */
 137                                 (void)brl_unlock(fsp->dev, fsp->inode, fsp->fnum,
 138                                                                 lock_pid, sys_getpid(), conn->cnum,
 139                                                                 offset, count, False,
 140                                                                 NULL, NULL);
 141                         }
 142                 }
 143         }
 144
 145         return status;
 146 }
 147
 148 /****************************************************************************
 149  Utility function called by locking requests. This is *DISGUSTING*. It also
 150  appears to be "What Windows Does" (tm). Andrew, ever wonder why Windows 2000
 151  is so slow on the locking tests...... ? This is the reason. Much though I hate
 152  it, we need this. JRA.
 153 ****************************************************************************/
 154
 155 NTSTATUS do_lock_spin(files_struct *fsp,connection_struct *conn, uint16 lock_pid,
 156                  SMB_BIG_UINT count,SMB_BIG_UINT offset,enum brl_type lock_type, BOOL *my_lock_ctx)
 157 {
 158         int j, maxj = lp_lock_spin_count();
 159         int sleeptime = lp_lock_sleep_time();
 160         NTSTATUS status, ret;
 161
 162         if (maxj <= 0)
 163                 maxj = 1;
 164
 165         ret = NT_STATUS_OK; /* to keep dumb compilers happy */
 166
 167         for (j = 0; j < maxj; j++) {
 168                 status = do_lock(fsp, conn, lock_pid, count, offset, lock_type, my_lock_ctx);
 169                 if (!NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED) &&
 170                     !NT_STATUS_EQUAL(status, NT_STATUS_FILE_LOCK_CONFLICT)) {
 171                         return status;
 172                 }
 173                 /* if we do fail then return the first error code we got */
 174                 if (j == 0) {
 175                         ret = status;
 176                         /* Don't spin if we blocked ourselves. */
 177                         if (*my_lock_ctx)
 178                                 return ret;
 179                 }
 180                 if (sleeptime)
 181                         sys_usleep(sleeptime);
 182         }
 183         return ret;
 184 }
 185
 186 /* Struct passed to brl_unlock. */
 187 struct posix_unlock_data_struct {
 188         files_struct *fsp;
 189         SMB_BIG_UINT offset;
 190         SMB_BIG_UINT count;
 191 };
 192
 193 /****************************************************************************
 194  Function passed to brl_unlock to allow POSIX unlock to be done first.
 195 ****************************************************************************/
 196
 197 static void posix_unlock(void *pre_data)
 198 {
 199         struct posix_unlock_data_struct *pdata = (struct posix_unlock_data_struct *)pre_data;
 200
 201         if (lp_posix_locking(SNUM(pdata->fsp->conn)))
 202                 release_posix_lock(pdata->fsp, pdata->offset, pdata->count);
 203 }
 204
 205 /****************************************************************************
 206  Utility function called by unlocking requests.
 207 ****************************************************************************/
 208
 209 NTSTATUS do_unlock(files_struct *fsp,connection_struct *conn, uint16 lock_pid,
 210                    SMB_BIG_UINT count,SMB_BIG_UINT offset)
 211 {
 212         BOOL ok = False;
 213         struct posix_unlock_data_struct posix_data;
 214
 215         if (!lp_locking(SNUM(conn)))
 216                 return NT_STATUS_OK;
 217
 218         if (!OPEN_FSP(fsp) || !fsp->can_lock || (fsp->conn != conn)) {
 219                 return NT_STATUS_INVALID_HANDLE;
 220         }
 221
 222         DEBUG(10,("do_unlock: unlock start=%.0f len=%.0f requested for file %s\n",
 223                   (double)offset, (double)count, fsp->fsp_name ));
 224
 225         /*
 226          * Remove the existing lock record from the tdb lockdb
 227          * before looking at POSIX locks. If this record doesn't
 228          * match then don't bother looking to remove POSIX locks.
 229          */
 230
 231         posix_data.fsp = fsp;
 232         posix_data.offset = offset;
 233         posix_data.count = count;
 234
 235         ok = brl_unlock(fsp->dev, fsp->inode, fsp->fnum,
 236                         lock_pid, sys_getpid(), conn->cnum, offset, count,
 237                         False, posix_unlock, (void *)&posix_data);
 238
 239         if (!ok) {
 240                 DEBUG(10,("do_unlock: returning ERRlock.\n" ));
 241                 return NT_STATUS_RANGE_NOT_LOCKED;
 242         }
 243         return NT_STATUS_OK;
 244 }
 245
 246 /****************************************************************************
 247  Remove any locks on this fd. Called from file_close().
 248 ****************************************************************************/
 249
 250 void locking_close_file(files_struct *fsp)
 251 {
 252         pid_t pid = sys_getpid();
 253
 254         if (!lp_locking(SNUM(fsp->conn)))
 255                 return;
 256
 257         /*
 258          * Just release all the brl locks, no need to release individually.
 259          */
 260
 261         brl_close(fsp->dev, fsp->inode, pid, fsp->conn->cnum, fsp->fnum);
 262
 263         if(lp_posix_locking(SNUM(fsp->conn))) {
 264
 265                 /*
 266                  * Release all the POSIX locks.
 267                  */
 268                 posix_locking_close_file(fsp);
 269
 270         }
 271 }
 272
 273 /****************************************************************************
 274  Initialise the locking functions.
 275 ****************************************************************************/
 276
 277 static int open_read_only;
 278
 279 BOOL locking_init(int read_only)
 280 {
 281         brl_init(read_only);
 282
 283         if (tdb)
 284                 return True;
 285
 286         tdb = tdb_open_log(lock_path("locking.tdb"),
 287                        0, TDB_DEFAULT|(read_only?0x0:TDB_CLEAR_IF_FIRST),
 288                        read_only?O_RDONLY:O_RDWR|O_CREAT,
 289                        0644);
 290
 291         if (!tdb) {
 292                 DEBUG(0,("ERROR: Failed to initialise locking database\n"));
 293                 return False;
 294         }
 295
 296         if (!posix_locking_init(read_only))
 297                 return False;
 298
 299         open_read_only = read_only;
 300
 301         return True;
 302 }
 303
 304 /*******************************************************************
 305  Deinitialize the share_mode management.
 306 ******************************************************************/
 307
 308 BOOL locking_end(void)
 309 {
 310
 311         brl_shutdown(open_read_only);
 312         if (tdb) {
 313
 314                 if (tdb_close(tdb) != 0)
 315                         return False;
 316         }
 317
 318         return True;
 319 }
 320
 321 /*******************************************************************
 322  Form a static locking key for a dev/inode pair.
 323 ******************************************************************/
 324
 325 static TDB_DATA locking_key(SMB_DEV_T dev, SMB_INO_T inode)
 326 {
 327         static struct locking_key key;
 328         TDB_DATA kbuf;
 329
 330         memset(&key, '\0', sizeof(key));
 331         key.dev = dev;
 332         key.inode = inode;
 333         kbuf.dptr = (char *)&key;
 334         kbuf.dsize = sizeof(key);
 335         return kbuf;
 336 }
 337
 338 static TDB_DATA locking_key_fsp(files_struct *fsp)
 339 {
 340         return locking_key(fsp->dev, fsp->inode);
 341 }
 342
 343 /*******************************************************************
 344  Lock a hash bucket entry.
 345 ******************************************************************/
 346
 347 BOOL lock_share_entry(connection_struct *conn,
 348                       SMB_DEV_T dev, SMB_INO_T inode)
 349 {
 350         return tdb_chainlock(tdb, locking_key(dev, inode)) == 0;
 351 }
 352
 353 /*******************************************************************
 354  Unlock a hash bucket entry.
 355 ******************************************************************/
 356
 357 void unlock_share_entry(connection_struct *conn,
 358                         SMB_DEV_T dev, SMB_INO_T inode)
 359 {
 360         tdb_chainunlock(tdb, locking_key(dev, inode));
 361 }
 362
 363 /*******************************************************************
 364  Lock a hash bucket entry. Use an fsp for convenience.
 365 ******************************************************************/
 366
 367 BOOL lock_share_entry_fsp(files_struct *fsp)
 368 {
 369         return tdb_chainlock(tdb, locking_key(fsp->dev, fsp->inode)) == 0;
 370 }
 371
 372 /*******************************************************************
 373  Unlock a hash bucket entry. Use an fsp for convenience.
 374 ******************************************************************/
 375
 376 void unlock_share_entry_fsp(files_struct *fsp)
 377 {
 378         tdb_chainunlock(tdb, locking_key(fsp->dev, fsp->inode));
 379 }
 380
 381 /*******************************************************************
 382  Print out a share mode.
 383 ********************************************************************/
 384
 385 char *share_mode_str(int num, share_mode_entry *e)
 386 {
 387         static pstring share_str;
 388
 389         slprintf(share_str, sizeof(share_str)-1, "share_mode_entry[%d]: \
 390 pid = %lu, share_mode = 0x%x, desired_access = 0x%x, port = 0x%x, type= 0x%x, file_id = %lu, dev = 0x%x, inode = %.0f",
 391         num, (unsigned long)e->pid, e->share_mode, (unsigned int)e->desired_access, e->op_port, e->op_type, e->share_file_id,
 392         (unsigned int)e->dev, (double)e->inode );
 393
 394         return share_str;
 395 }
 396
 397 /*******************************************************************
 398  Print out a share mode table.
 399 ********************************************************************/
 400
 401 static void print_share_mode_table(struct locking_data *data)
 402 {
 403         int num_share_modes = data->u.num_share_mode_entries;
 404         share_mode_entry *shares = (share_mode_entry *)(data + 1);
 405         int i;
 406
 407         for (i = 0; i < num_share_modes; i++) {
 408                 share_mode_entry *entry_p = &shares[i];
 409                 DEBUG(10,("print_share_mode_table: %s\n", share_mode_str(i, entry_p) ));
 410         }
 411 }
 412
 413 /*******************************************************************
 414  Get all share mode entries for a dev/inode pair.
 415 ********************************************************************/
 416
 417 int get_share_modes(connection_struct *conn,
 418                     SMB_DEV_T dev, SMB_INO_T inode,
 419                     share_mode_entry **pp_shares)
 420 {
 421         TDB_DATA dbuf;
 422         struct locking_data *data;
 423         int num_share_modes;
 424         share_mode_entry *shares = NULL;
 425         TDB_DATA key = locking_key(dev, inode);
 426         *pp_shares = NULL;
 427
 428         dbuf = tdb_fetch(tdb, key);
 429         if (!dbuf.dptr)
 430                 return 0;
 431
 432         data = (struct locking_data *)dbuf.dptr;
 433         num_share_modes = data->u.num_share_mode_entries;
 434         if(num_share_modes) {
 435                 int i;
 436                 int del_count = 0;
 437
 438                 shares = (share_mode_entry *)memdup(dbuf.dptr + sizeof(*data),
 439                                                 num_share_modes * sizeof(share_mode_entry));
 440
 441                 if (!shares) {
 442                         SAFE_FREE(dbuf.dptr);
 443                         return 0;
 444                 }
 445
 446                 /*
 447                  * Ensure that each entry has a real process attached.
 448                  */
 449
 450                 for (i = 0; i < num_share_modes; ) {
 451                         share_mode_entry *entry_p = &shares[i];
 452                         if (process_exists(entry_p->pid)) {
 453                                 DEBUG(10,("get_share_modes: %s\n", share_mode_str(i, entry_p) ));
 454                                 i++;
 455                         } else {
 456                                 DEBUG(10,("get_share_modes: deleted %s\n", share_mode_str(i, entry_p) ));
 457                                 memcpy( &shares[i], &shares[i+1],
 458                                         sizeof(share_mode_entry) * (num_share_modes - i - 1));
 459                                 num_share_modes--;
 460                                 del_count++;
 461                         }
 462                 }
 463
 464                 /* Did we delete any ? If so, re-store in tdb. */
 465                 if (del_count) {
 466                         data->u.num_share_mode_entries = num_share_modes;
 467
 468                         if (num_share_modes)
 469                                 memcpy(dbuf.dptr + sizeof(*data), shares,
 470                                                 num_share_modes * sizeof(share_mode_entry));
 471
 472                         /* The record has shrunk a bit */
 473                         dbuf.dsize -= del_count * sizeof(share_mode_entry);
 474
 475                         if (tdb_store(tdb, key, dbuf, TDB_REPLACE) == -1) {
 476                                 SAFE_FREE(shares);
 477                                 SAFE_FREE(dbuf.dptr);
 478                                 return 0;
 479                         }
 480                 }
 481         }
 482
 483         SAFE_FREE(dbuf.dptr);
 484         *pp_shares = shares;
 485         return num_share_modes;
 486 }
 487
 488 /*******************************************************************
 489  Fill a share mode entry.
 490 ********************************************************************/
 491
 492 static void fill_share_mode(char *p, files_struct *fsp, uint16 port, uint16 op_type)
 493 {
 494         share_mode_entry *e = (share_mode_entry *)p;
 495         void *x = &e->time; /* Needed to force alignment. p may not be aligned.... */
 496
 497         memset(e, '\0', sizeof(share_mode_entry));
 498         e->pid = sys_getpid();
 499         e->share_mode = fsp->share_mode;
 500         e->desired_access = fsp->desired_access;
 501         e->op_port = port;
 502         e->op_type = op_type;
 503         memcpy(x, &fsp->open_time, sizeof(struct timeval));
 504         e->share_file_id = fsp->file_id;
 505         e->dev = fsp->dev;
 506         e->inode = fsp->inode;
 507 }
 508
 509 /*******************************************************************
 510  Check if two share mode entries are identical, ignoring oplock
 511  and port info and desired_access.
 512 ********************************************************************/
 513
 514 BOOL share_modes_identical( share_mode_entry *e1, share_mode_entry *e2)
 515 {
 516 #if 1 /* JRA PARANOIA TEST - REMOVE LATER */
 517         if (e1->pid == e2->pid &&
 518                 e1->share_file_id == e2->share_file_id &&
 519                 e1->dev == e2->dev &&
 520                 e1->inode == e2->inode &&
 521                 (e1->share_mode & ~DELETE_ON_CLOSE_FLAG) != (e2->share_mode & ~DELETE_ON_CLOSE_FLAG)) {
 522                         DEBUG(0,("PANIC: share_modes_identical: share_mode missmatch (e1 = %u, e2 = %u). Logic error.\n",
 523                                 (unsigned int)(e1->share_mode & ~DELETE_ON_CLOSE_FLAG),
 524                                 (unsigned int)(e2->share_mode & ~DELETE_ON_CLOSE_FLAG) ));
 525                 smb_panic("PANIC: share_modes_identical logic error.\n");
 526         }
 527 #endif
 528
 529         return (e1->pid == e2->pid &&
 530                 (e1->share_mode & ~DELETE_ON_CLOSE_FLAG) == (e2->share_mode & ~DELETE_ON_CLOSE_FLAG) &&
 531                 e1->dev == e2->dev &&
 532                 e1->inode == e2->inode &&
 533                 e1->share_file_id == e2->share_file_id );
 534 }
 535
 536 /*******************************************************************
 537  Delete a specific share mode. Return the number
 538  of entries left, and a memdup'ed copy of the entry deleted (if required).
 539  Ignore if no entry deleted.
 540 ********************************************************************/
 541
 542 ssize_t del_share_entry( SMB_DEV_T dev, SMB_INO_T inode,
 543                         share_mode_entry *entry, share_mode_entry **ppse)
 544 {
 545         TDB_DATA dbuf;
 546         struct locking_data *data;
 547         int i, del_count=0;
 548         share_mode_entry *shares;
 549         ssize_t count = 0;
 550         TDB_DATA key = locking_key(dev, inode);
 551
 552         if (ppse)
 553                 *ppse = NULL;
 554
 555         /* read in the existing share modes */
 556         dbuf = tdb_fetch(tdb, key);
 557         if (!dbuf.dptr)
 558                 return -1;
 559
 560         data = (struct locking_data *)dbuf.dptr;
 561         shares = (share_mode_entry *)(dbuf.dptr + sizeof(*data));
 562
 563         /*
 564          * Find any with this pid and delete it
 565          * by overwriting with the rest of the data
 566          * from the record.
 567          */
 568
 569         DEBUG(10,("del_share_entry: num_share_modes = %d\n", data->u.num_share_mode_entries ));
 570
 571         for (i=0;i<data->u.num_share_mode_entries;) {
 572                 if (share_modes_identical(&shares[i], entry)) {
 573                         DEBUG(10,("del_share_entry: deleted %s\n",
 574                                 share_mode_str(i, &shares[i]) ));
 575                         if (ppse)
 576                                 *ppse = memdup(&shares[i], sizeof(*shares));
 577                         data->u.num_share_mode_entries--;
 578                         memmove(&shares[i], &shares[i+1],
 579                                 dbuf.dsize - (sizeof(*data) + (i+1)*sizeof(*shares)));
 580                         del_count++;
 581
 582                         DEBUG(10,("del_share_entry: deleting entry %d\n", i ));
 583
 584                 } else {
 585                         i++;
 586                 }
 587         }
 588
 589         if (del_count) {
 590                 /* the record may have shrunk a bit */
 591                 dbuf.dsize -= del_count * sizeof(*shares);
 592
 593                 count = (ssize_t)data->u.num_share_mode_entries;
 594
 595                 /* store it back in the database */
 596                 if (data->u.num_share_mode_entries == 0) {
 597                         if (tdb_delete(tdb, key) == -1)
 598                                 count = -1;
 599                 } else {
 600                         if (tdb_store(tdb, key, dbuf, TDB_REPLACE) == -1)
 601                                 count = -1;
 602                 }
 603         }
 604         DEBUG(10,("del_share_entry: Remaining table.\n"));
 605         print_share_mode_table((struct locking_data *)dbuf.dptr);
 606         SAFE_FREE(dbuf.dptr);
 607         return count;
 608 }
 609
 610 /*******************************************************************
 611  Del the share mode of a file for this process. Return the number
 612  of entries left, and a memdup'ed copy of the entry deleted.
 613 ********************************************************************/
 614
 615 ssize_t del_share_mode(files_struct *fsp, share_mode_entry **ppse)
 616 {
 617         share_mode_entry entry;
 618
 619         /*
 620          * Fake up a share_mode_entry for comparisons.
 621          */
 622
 623         fill_share_mode((char *)&entry, fsp, 0, 0);
 624         return del_share_entry(fsp->dev, fsp->inode, &entry, ppse);
 625 }
 626
 627 /*******************************************************************
 628  Set the share mode of a file. Return False on fail, True on success.
 629 ********************************************************************/
 630
 631 BOOL set_share_mode(files_struct *fsp, uint16 port, uint16 op_type)
 632 {
 633         TDB_DATA dbuf;
 634         struct locking_data *data;
 635         char *p=NULL;
 636         int size;
 637         TDB_DATA key = locking_key_fsp(fsp);
 638         BOOL ret = True;
 639
 640         /* read in the existing share modes if any */
 641         dbuf = tdb_fetch(tdb, key);
 642         if (!dbuf.dptr) {
 643                 size_t offset;
 644                 /* we'll need to create a new record */
 645                 pstring fname;
 646
 647                 pstrcpy(fname, fsp->conn->connectpath);
 648                 pstrcat(fname, "/");
 649                 pstrcat(fname, fsp->fsp_name);
 650
 651                 size = sizeof(*data) + sizeof(share_mode_entry) + strlen(fname) + 1;
 652                 p = (char *)malloc(size);
 653                 if (!p)
 654                         return False;
 655                 data = (struct locking_data *)p;
 656                 data->u.num_share_mode_entries = 1;
 657
 658                 DEBUG(10,("set_share_mode: creating entry for file %s. num_share_modes = 1\n",
 659                         fsp->fsp_name ));
 660
 661                 offset = sizeof(*data) + sizeof(share_mode_entry);
 662                 safe_strcpy(p + offset, fname, size - offset - 1);
 663                 fill_share_mode(p + sizeof(*data), fsp, port, op_type);
 664                 dbuf.dptr = p;
 665                 dbuf.dsize = size;
 666                 if (tdb_store(tdb, key, dbuf, TDB_REPLACE) == -1)
 667                         ret = False;
 668
 669                 print_share_mode_table((struct locking_data *)p);
 670
 671                 SAFE_FREE(p);
 672                 return ret;
 673         }
 674
 675         /* we're adding to an existing entry - this is a bit fiddly */
 676         data = (struct locking_data *)dbuf.dptr;
 677
 678         data->u.num_share_mode_entries++;
 679
 680         DEBUG(10,("set_share_mode: adding entry for file %s. new num_share_modes = %d\n",
 681                 fsp->fsp_name, data->u.num_share_mode_entries ));
 682
 683         size = dbuf.dsize + sizeof(share_mode_entry);
 684         p = malloc(size);
 685         if (!p) {
 686                 SAFE_FREE(dbuf.dptr);
 687                 return False;
 688         }
 689         memcpy(p, dbuf.dptr, sizeof(*data));
 690         fill_share_mode(p + sizeof(*data), fsp, port, op_type);
 691         memcpy(p + sizeof(*data) + sizeof(share_mode_entry), dbuf.dptr + sizeof(*data),
 692                dbuf.dsize - sizeof(*data));
 693         SAFE_FREE(dbuf.dptr);
 694         dbuf.dptr = p;
 695         dbuf.dsize = size;
 696         if (tdb_store(tdb, key, dbuf, TDB_REPLACE) == -1)
 697                 ret = False;
 698         print_share_mode_table((struct locking_data *)p);
 699         SAFE_FREE(p);
 700         return ret;
 701 }
 702
 703 /*******************************************************************
 704  A generic in-place modification call for share mode entries.
 705 ********************************************************************/
 706
 707 static BOOL mod_share_mode( SMB_DEV_T dev, SMB_INO_T inode, share_mode_entry *entry,
 708                            void (*mod_fn)(share_mode_entry *, SMB_DEV_T, SMB_INO_T, void *),
 709                            void *param)
 710 {
 711         TDB_DATA dbuf;
 712         struct locking_data *data;
 713         int i;
 714         share_mode_entry *shares;
 715         BOOL need_store=False;
 716         BOOL ret = True;
 717         TDB_DATA key = locking_key(dev, inode);
 718
 719         /* read in the existing share modes */
 720         dbuf = tdb_fetch(tdb, key);
 721         if (!dbuf.dptr)
 722                 return False;
 723
 724         data = (struct locking_data *)dbuf.dptr;
 725         shares = (share_mode_entry *)(dbuf.dptr + sizeof(*data));
 726
 727         /* find any with our pid and call the supplied function */
 728         for (i=0;i<data->u.num_share_mode_entries;i++) {
 729                 if (share_modes_identical(entry, &shares[i])) {
 730                         mod_fn(&shares[i], dev, inode, param);
 731                         need_store=True;
 732                 }
 733         }
 734
 735         /* if the mod fn was called then store it back */
 736         if (need_store) {
 737                 if (data->u.num_share_mode_entries == 0) {
 738                         if (tdb_delete(tdb, key) == -1)
 739                                 ret = False;
 740                 } else {
 741                         if (tdb_store(tdb, key, dbuf, TDB_REPLACE) == -1)
 742                                 ret = False;
 743                 }
 744         }
 745
 746         SAFE_FREE(dbuf.dptr);
 747         return ret;
 748 }
 749
 750 /*******************************************************************
 751  Static function that actually does the work for the generic function
 752  below.
 753 ********************************************************************/
 754
 755 static void remove_share_oplock_fn(share_mode_entry *entry, SMB_DEV_T dev, SMB_INO_T inode,
 756                                    void *param)
 757 {
 758         DEBUG(10,("remove_share_oplock_fn: removing oplock info for entry dev=%x ino=%.0f\n",
 759                   (unsigned int)dev, (double)inode ));
 760         /* Delete the oplock info. */
 761         entry->op_port = 0;
 762         entry->op_type = NO_OPLOCK;
 763 }
 764
 765 /*******************************************************************
 766  Remove an oplock port and mode entry from a share mode.
 767 ********************************************************************/
 768
 769 BOOL remove_share_oplock(files_struct *fsp)
 770 {
 771         share_mode_entry entry;
 772         /*
 773          * Fake up an entry for comparisons...
 774          */
 775         fill_share_mode((char *)&entry, fsp, 0, 0);
 776         return mod_share_mode(fsp->dev, fsp->inode, &entry, remove_share_oplock_fn, NULL);
 777 }
 778
 779 /*******************************************************************
 780  Static function that actually does the work for the generic function
 781  below.
 782 ********************************************************************/
 783
 784 static void downgrade_share_oplock_fn(share_mode_entry *entry, SMB_DEV_T dev, SMB_INO_T inode,
 785                                    void *param)
 786 {
 787         DEBUG(10,("downgrade_share_oplock_fn: downgrading oplock info for entry dev=%x ino=%.0f\n",
 788                   (unsigned int)dev, (double)inode ));
 789         entry->op_type = LEVEL_II_OPLOCK;
 790 }
 791
 792 /*******************************************************************
 793  Downgrade a oplock type from exclusive to level II.
 794 ********************************************************************/
 795
 796 BOOL downgrade_share_oplock(files_struct *fsp)
 797 {
 798         share_mode_entry entry;
 799         /*
 800          * Fake up an entry for comparisons...
 801          */
 802         fill_share_mode((char *)&entry, fsp, 0, 0);
 803         return mod_share_mode(fsp->dev, fsp->inode, &entry, downgrade_share_oplock_fn, NULL);
 804 }
 805
 806 /*******************************************************************
 807  Get/Set the delete on close flag in a set of share modes.
 808  Return False on fail, True on success.
 809 ********************************************************************/
 810
 811 BOOL modify_delete_flag( SMB_DEV_T dev, SMB_INO_T inode, BOOL delete_on_close)
 812 {
 813         TDB_DATA dbuf;
 814         struct locking_data *data;
 815         int i;
 816         share_mode_entry *shares;
 817         TDB_DATA key = locking_key(dev, inode);
 818
 819         /* read in the existing share modes */
 820         dbuf = tdb_fetch(tdb, key);
 821         if (!dbuf.dptr)
 822                 return False;
 823
 824         data = (struct locking_data *)dbuf.dptr;
 825         shares = (share_mode_entry *)(dbuf.dptr + sizeof(*data));
 826
 827         /* Set/Unset the delete on close element. */
 828         for (i=0;i<data->u.num_share_mode_entries;i++,shares++) {
 829                 shares->share_mode = (delete_on_close ?
 830                             (shares->share_mode | DELETE_ON_CLOSE_FLAG) :
 831                             (shares->share_mode & ~DELETE_ON_CLOSE_FLAG) );
 832         }
 833
 834         /* store it back */
 835         if (data->u.num_share_mode_entries) {
 836                 if (tdb_store(tdb, key, dbuf, TDB_REPLACE)==-1) {
 837                         SAFE_FREE(dbuf.dptr);
 838                         return False;
 839                 }
 840         }
 841
 842         SAFE_FREE(dbuf.dptr);
 843         return True;
 844 }
 845
 846 /****************************************************************************
 847  Traverse the whole database with this function, calling traverse_callback
 848  on each share mode
 849 ****************************************************************************/
 850
 851 static int traverse_fn(TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf,
 852                        void* state)
 853 {
 854         struct locking_data *data;
 855         share_mode_entry *shares;
 856         char *name;
 857         int i;
 858
 859         SHAREMODE_FN(traverse_callback) = (SHAREMODE_FN_CAST())state;
 860
 861         data = (struct locking_data *)dbuf.dptr;
 862         shares = (share_mode_entry *)(dbuf.dptr + sizeof(*data));
 863         name = dbuf.dptr + sizeof(*data) + data->u.num_share_mode_entries*sizeof(*shares);
 864
 865         for (i=0;i<data->u.num_share_mode_entries;i++) {
 866                 traverse_callback(&shares[i], name);
 867         }
 868         return 0;
 869 }
 870
 871 /*******************************************************************
 872  Call the specified function on each entry under management by the
 873  share mode system.
 874 ********************************************************************/
 875
 876 int share_mode_forall(SHAREMODE_FN(fn))
 877 {
 878         if (!tdb)
 879                 return 0;
 880         return tdb_traverse(tdb, traverse_fn, (void*)fn);
 881 }