source3/locking/share_mode_lock.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Locking functions
   4    Copyright (C) Andrew Tridgell 1992-2000
   5    Copyright (C) Jeremy Allison 1992-2006
   6    Copyright (C) Volker Lendecke 2005
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  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    rewritten completely to use new tdb code. Tridge, Dec '99
  33
  34    Added POSIX locking support. Jeremy Allison (jeremy@valinux.com), Apr. 2000.
  35    Added Unix Extensions POSIX locking support. Jeremy Allison Mar 2006.
  36 */
  37
  38 #include "includes.h"
  39 #include "system/filesys.h"
  40 #include "locking/proto.h"
  41 #include "smbd/globals.h"
  42 #include "dbwrap/dbwrap.h"
  43 #include "dbwrap/dbwrap_open.h"
  44 #include "../libcli/security/security.h"
  45 #include "serverid.h"
  46 #include "messages.h"
  47 #include "util_tdb.h"
  48 #include "../librpc/gen_ndr/ndr_open_files.h"
  49 #include "source3/lib/dbwrap/dbwrap_watch.h"
  50
  51 #undef DBGC_CLASS
  52 #define DBGC_CLASS DBGC_LOCKING
  53
  54 #define NO_LOCKING_COUNT (-1)
  55
  56 /* the locking database handle */
  57 static struct db_context *lock_db;
  58
  59 static bool locking_init_internal(bool read_only)
  60 {
  61         brl_init(read_only);
  62
  63         if (lock_db)
  64                 return True;
  65
  66         lock_db = db_open(NULL, lock_path("locking.tdb"),
  67                           lp_open_files_db_hash_size(),
  68                           TDB_DEFAULT|TDB_VOLATILE|TDB_CLEAR_IF_FIRST|TDB_INCOMPATIBLE_HASH,
  69                           read_only?O_RDONLY:O_RDWR|O_CREAT, 0644,
  70                           DBWRAP_LOCK_ORDER_1);
  71
  72         if (!lock_db) {
  73                 DEBUG(0,("ERROR: Failed to initialise locking database\n"));
  74                 return False;
  75         }
  76
  77         if (!posix_locking_init(read_only))
  78                 return False;
  79
  80         dbwrap_watch_db(lock_db, server_messaging_context());
  81
  82         return True;
  83 }
  84
  85 bool locking_init(void)
  86 {
  87         return locking_init_internal(false);
  88 }
  89
  90 bool locking_init_readonly(void)
  91 {
  92         return locking_init_internal(true);
  93 }
  94
  95 /*******************************************************************
  96  Deinitialize the share_mode management.
  97 ******************************************************************/
  98
  99 bool locking_end(void)
 100 {
 101         brl_shutdown();
 102         TALLOC_FREE(lock_db);
 103         return true;
 104 }
 105
 106 /*******************************************************************
 107  Form a static locking key for a dev/inode pair.
 108 ******************************************************************/
 109
 110 static TDB_DATA locking_key(const struct file_id *id)
 111 {
 112         return make_tdb_data((const uint8_t *)id, sizeof(*id));
 113 }
 114
 115 /*******************************************************************
 116  Get all share mode entries for a dev/inode pair.
 117 ********************************************************************/
 118
 119 static struct share_mode_data *parse_share_modes(TALLOC_CTX *mem_ctx,
 120                                                  const TDB_DATA dbuf)
 121 {
 122         struct share_mode_data *d;
 123         enum ndr_err_code ndr_err;
 124         uint32_t i;
 125         DATA_BLOB blob;
 126
 127         d = talloc(mem_ctx, struct share_mode_data);
 128         if (d == NULL) {
 129                 DEBUG(0, ("talloc failed\n"));
 130                 goto fail;
 131         }
 132
 133         blob.data = dbuf.dptr;
 134         blob.length = dbuf.dsize;
 135
 136         ndr_err = ndr_pull_struct_blob(
 137                 &blob, d, d, (ndr_pull_flags_fn_t)ndr_pull_share_mode_data);
 138         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 139                 DEBUG(1, ("ndr_pull_share_mode_lock failed: %s\n",
 140                           ndr_errstr(ndr_err)));
 141                 goto fail;
 142         }
 143
 144         /*
 145          * Initialize the values that are [skip] in the idl. The NDR code does
 146          * not initialize them.
 147          */
 148
 149         for (i=0; i<d->num_share_modes; i++) {
 150                 d->share_modes[i].stale = false;
 151         }
 152         d->modified = false;
 153         d->fresh = false;
 154
 155         if (DEBUGLEVEL >= 10) {
 156                 DEBUG(10, ("parse_share_modes:\n"));
 157                 NDR_PRINT_DEBUG(share_mode_data, d);
 158         }
 159
 160         return d;
 161 fail:
 162         TALLOC_FREE(d);
 163         return NULL;
 164 }
 165
 166 /*******************************************************************
 167  Create a storable data blob from a modified share_mode_data struct.
 168 ********************************************************************/
 169
 170 static TDB_DATA unparse_share_modes(struct share_mode_data *d)
 171 {
 172         DATA_BLOB blob;
 173         enum ndr_err_code ndr_err;
 174
 175         if (DEBUGLEVEL >= 10) {
 176                 DEBUG(10, ("unparse_share_modes:\n"));
 177                 NDR_PRINT_DEBUG(share_mode_data, d);
 178         }
 179
 180         remove_stale_share_mode_entries(d);
 181
 182         if (d->num_share_modes == 0) {
 183                 DEBUG(10, ("No used share mode found\n"));
 184                 return make_tdb_data(NULL, 0);
 185         }
 186
 187         ndr_err = ndr_push_struct_blob(
 188                 &blob, d, d, (ndr_push_flags_fn_t)ndr_push_share_mode_data);
 189         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 190                 smb_panic("ndr_push_share_mode_lock failed");
 191         }
 192
 193         return make_tdb_data(blob.data, blob.length);
 194 }
 195
 196 /*******************************************************************
 197  If modified, store the share_mode_data back into the database.
 198 ********************************************************************/
 199
 200 static int share_mode_data_destructor(struct share_mode_data *d)
 201 {
 202         NTSTATUS status;
 203         TDB_DATA data;
 204
 205         if (!d->modified) {
 206                 return 0;
 207         }
 208
 209         data = unparse_share_modes(d);
 210
 211         if (data.dptr == NULL) {
 212                 if (!d->fresh) {
 213                         /* There has been an entry before, delete it */
 214
 215                         status = dbwrap_record_delete(d->record);
 216                         if (!NT_STATUS_IS_OK(status)) {
 217                                 char *errmsg;
 218
 219                                 DEBUG(0, ("delete_rec returned %s\n",
 220                                           nt_errstr(status)));
 221
 222                                 if (asprintf(&errmsg, "could not delete share "
 223                                              "entry: %s\n",
 224                                              nt_errstr(status)) == -1) {
 225                                         smb_panic("could not delete share"
 226                                                   "entry");
 227                                 }
 228                                 smb_panic(errmsg);
 229                         }
 230                 }
 231                 goto done;
 232         }
 233
 234         status = dbwrap_record_store(d->record, data, TDB_REPLACE);
 235         if (!NT_STATUS_IS_OK(status)) {
 236                 char *errmsg;
 237
 238                 DEBUG(0, ("store returned %s\n", nt_errstr(status)));
 239
 240                 if (asprintf(&errmsg, "could not store share mode entry: %s",
 241                              nt_errstr(status)) == -1) {
 242                         smb_panic("could not store share mode entry");
 243                 }
 244                 smb_panic(errmsg);
 245         }
 246
 247  done:
 248
 249         return 0;
 250 }
 251
 252 /*******************************************************************
 253  Allocate a new share_mode_data struct, mark it unmodified.
 254  fresh is set to note that currently there is no database entry.
 255 ********************************************************************/
 256
 257 static struct share_mode_data *fresh_share_mode_lock(
 258         TALLOC_CTX *mem_ctx, const char *servicepath,
 259         const struct smb_filename *smb_fname,
 260         const struct timespec *old_write_time)
 261 {
 262         struct share_mode_data *d;
 263
 264         if ((servicepath == NULL) || (smb_fname == NULL) ||
 265             (old_write_time == NULL)) {
 266                 return NULL;
 267         }
 268
 269         d = talloc_zero(mem_ctx, struct share_mode_data);
 270         if (d == NULL) {
 271                 goto fail;
 272         }
 273         d->base_name = talloc_strdup(d, smb_fname->base_name);
 274         if (d->base_name == NULL) {
 275                 goto fail;
 276         }
 277         if (smb_fname->stream_name != NULL) {
 278                 d->stream_name = talloc_strdup(d, smb_fname->stream_name);
 279                 if (d->stream_name == NULL) {
 280                         goto fail;
 281                 }
 282         }
 283         d->servicepath = talloc_strdup(d, servicepath);
 284         if (d->servicepath == NULL) {
 285                 goto fail;
 286         }
 287         d->old_write_time = *old_write_time;
 288         d->modified = false;
 289         d->fresh = true;
 290         return d;
 291 fail:
 292         DEBUG(0, ("talloc failed\n"));
 293         TALLOC_FREE(d);
 294         return NULL;
 295 }
 296
 297 /*******************************************************************
 298  Either fetch a share mode from the database, or allocate a fresh
 299  one if the record doesn't exist.
 300 ********************************************************************/
 301
 302 static struct share_mode_lock *get_share_mode_lock_internal(
 303         TALLOC_CTX *mem_ctx, struct file_id id,
 304         const char *servicepath, const struct smb_filename *smb_fname,
 305         const struct timespec *old_write_time)
 306 {
 307         struct share_mode_lock *lck;
 308         struct share_mode_data *d;
 309         struct db_record *rec;
 310         TDB_DATA key = locking_key(&id);
 311         TDB_DATA value;
 312
 313         rec = dbwrap_fetch_locked(lock_db, mem_ctx, key);
 314         if (rec == NULL) {
 315                 DEBUG(3, ("Could not lock share entry\n"));
 316                 return NULL;
 317         }
 318
 319         value = dbwrap_record_get_value(rec);
 320
 321         if (value.dptr == NULL) {
 322                 d = fresh_share_mode_lock(mem_ctx, servicepath, smb_fname,
 323                                           old_write_time);
 324         } else {
 325                 d = parse_share_modes(mem_ctx, value);
 326         }
 327
 328         if (d == NULL) {
 329                 DEBUG(5, ("get_share_mode_lock_internal: "
 330                         "Could not get share mode lock\n"));
 331                 TALLOC_FREE(rec);
 332                 return NULL;
 333         }
 334         d->id = id;
 335         d->record = talloc_move(d, &rec);
 336         talloc_set_destructor(d, share_mode_data_destructor);
 337
 338         lck = talloc(mem_ctx, struct share_mode_lock);
 339         if (lck == NULL) {
 340                 DEBUG(1, ("talloc failed\n"));
 341                 TALLOC_FREE(d);
 342                 return NULL;
 343         }
 344         lck->data = talloc_move(lck, &d);
 345         return lck;
 346 }
 347
 348 /*
 349  * We can only ever have one share mode locked. Users of
 350  * get_share_mode_lock never see this, it will be refcounted by
 351  * talloc_reference.
 352  */
 353 static struct share_mode_lock *the_lock;
 354
 355 static int the_lock_destructor(struct share_mode_lock *l)
 356 {
 357         the_lock = NULL;
 358         return 0;
 359 }
 360
 361 /*******************************************************************
 362  Get a share_mode_lock, Reference counted to allow nested calls.
 363 ********************************************************************/
 364
 365 struct share_mode_lock *get_share_mode_lock(
 366         TALLOC_CTX *mem_ctx,
 367         struct file_id id,
 368         const char *servicepath,
 369         const struct smb_filename *smb_fname,
 370         const struct timespec *old_write_time)
 371 {
 372         TALLOC_CTX *frame = talloc_stackframe();
 373
 374         struct share_mode_lock *lck;
 375
 376         if (the_lock == NULL) {
 377                 the_lock = get_share_mode_lock_internal(
 378                         frame, id, servicepath, smb_fname, old_write_time);
 379                 if (the_lock == NULL) {
 380                         goto fail;
 381                 }
 382                 talloc_set_destructor(the_lock, the_lock_destructor);
 383         }
 384         if (!file_id_equal(&the_lock->data->id, &id)) {
 385                 DEBUG(1, ("Can not lock two share modes simultaneously\n"));
 386                 goto fail;
 387         }
 388         lck = talloc(mem_ctx, struct share_mode_lock);
 389         if (lck == NULL) {
 390                 DEBUG(1, ("talloc failed\n"));
 391                 goto fail;
 392         }
 393         if (talloc_reference(lck, the_lock) == NULL) {
 394                 DEBUG(1, ("talloc_reference failed\n"));
 395                 goto fail;
 396         }
 397         lck->data = the_lock->data;
 398         TALLOC_FREE(frame);
 399         return lck;
 400 fail:
 401         TALLOC_FREE(frame);
 402         return NULL;
 403 }
 404
 405 static void fetch_share_mode_unlocked_parser(
 406         TDB_DATA key, TDB_DATA data, void *private_data)
 407 {
 408         struct share_mode_lock *lck = talloc_get_type_abort(
 409                 private_data, struct share_mode_lock);
 410
 411         lck->data = parse_share_modes(lck, data);
 412 }
 413
 414 /*******************************************************************
 415  Get a share_mode_lock without locking the database or reference
 416  counting. Used by smbstatus to display existing share modes.
 417 ********************************************************************/
 418
 419 struct share_mode_lock *fetch_share_mode_unlocked(TALLOC_CTX *mem_ctx,
 420                                                   struct file_id id)
 421 {
 422         struct share_mode_lock *lck;
 423         TDB_DATA key = locking_key(&id);
 424         NTSTATUS status;
 425
 426         lck = talloc(mem_ctx, struct share_mode_lock);
 427         if (lck == NULL) {
 428                 DEBUG(0, ("talloc failed\n"));
 429                 return NULL;
 430         }
 431         status = dbwrap_parse_record(
 432                 lock_db, key, fetch_share_mode_unlocked_parser, lck);
 433         if (!NT_STATUS_IS_OK(status) ||
 434             (lck->data == NULL)) {
 435                 TALLOC_FREE(lck);
 436                 return NULL;
 437         }
 438         return lck;
 439 }
 440
 441 struct forall_state {
 442         void (*fn)(const struct share_mode_entry *entry,
 443                    const char *sharepath,
 444                    const char *fname,
 445                    void *private_data);
 446         void *private_data;
 447 };
 448
 449 static int traverse_fn(struct db_record *rec, void *_state)
 450 {
 451         struct forall_state *state = (struct forall_state *)_state;
 452         uint32_t i;
 453         TDB_DATA key;
 454         TDB_DATA value;
 455         DATA_BLOB blob;
 456         enum ndr_err_code ndr_err;
 457         struct share_mode_data *d;
 458
 459         key = dbwrap_record_get_key(rec);
 460         value = dbwrap_record_get_value(rec);
 461
 462         /* Ensure this is a locking_key record. */
 463         if (key.dsize != sizeof(struct file_id))
 464                 return 0;
 465
 466         d = talloc(talloc_tos(), struct share_mode_data);
 467         if (d == NULL) {
 468                 return 0;
 469         }
 470
 471         blob.data = value.dptr;
 472         blob.length = value.dsize;
 473
 474         ndr_err = ndr_pull_struct_blob(
 475                 &blob, d, d, (ndr_pull_flags_fn_t)ndr_pull_share_mode_data);
 476         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 477                 DEBUG(1, ("ndr_pull_share_mode_lock failed\n"));
 478                 return 0;
 479         }
 480         if (DEBUGLEVEL > 10) {
 481                 DEBUG(11, ("parse_share_modes:\n"));
 482                 NDR_PRINT_DEBUG(share_mode_data, d);
 483         }
 484         for (i=0; i<d->num_share_modes; i++) {
 485                 state->fn(&d->share_modes[i],
 486                           d->servicepath, d->base_name,
 487                           state->private_data);
 488         }
 489         TALLOC_FREE(d);
 490
 491         return 0;
 492 }
 493
 494 /*******************************************************************
 495  Call the specified function on each entry under management by the
 496  share mode system.
 497 ********************************************************************/
 498
 499 int share_mode_forall(void (*fn)(const struct share_mode_entry *, const char *,
 500                                  const char *, void *),
 501                       void *private_data)
 502 {
 503         struct forall_state state;
 504         NTSTATUS status;
 505         int count;
 506
 507         if (lock_db == NULL)
 508                 return 0;
 509
 510         state.fn = fn;
 511         state.private_data = private_data;
 512
 513         status = dbwrap_traverse_read(lock_db, traverse_fn, (void *)&state,
 514                                       &count);
 515
 516         if (!NT_STATUS_IS_OK(status)) {
 517                 return -1;
 518         } else {
 519                 return count;
 520         }
 521 }
 522
 523 bool share_mode_cleanup_disconnected(struct file_id fid,
 524                                      uint64_t open_persistent_id)
 525 {
 526         bool ret = false;
 527         TALLOC_CTX *frame = talloc_stackframe();
 528         unsigned n;
 529         struct share_mode_data *data;
 530         struct share_mode_lock *lck;
 531         bool ok;
 532
 533         lck = get_existing_share_mode_lock(frame, fid);
 534         if (lck == NULL) {
 535                 DEBUG(5, ("share_mode_cleanup_disconnected: "
 536                           "Could not fetch share mode entry for %s\n",
 537                           file_id_string(frame, &fid)));
 538                 goto done;
 539         }
 540         data = lck->data;
 541
 542         for (n=0; n < data->num_share_modes; n++) {
 543                 struct share_mode_entry *entry = &data->share_modes[n];
 544
 545                 if (!server_id_is_disconnected(&entry->pid)) {
 546                         DEBUG(5, ("share_mode_cleanup_disconnected: "
 547                                   "file (file-id='%s', servicepath='%s', "
 548                                   "base_name='%s%s%s') "
 549                                   "is used by server %s ==> do not cleanup\n",
 550                                   file_id_string(frame, &fid),
 551                                   data->servicepath,
 552                                   data->base_name,
 553                                   (data->stream_name == NULL)
 554                                   ? "" : "', stream_name='",
 555                                   (data->stream_name == NULL)
 556                                   ? "" : data->stream_name,
 557                                   server_id_str(frame, &entry->pid)));
 558                         goto done;
 559                 }
 560                 if (open_persistent_id != entry->share_file_id) {
 561                         DEBUG(5, ("share_mode_cleanup_disconnected: "
 562                                   "entry for file "
 563                                   "(file-id='%s', servicepath='%s', "
 564                                   "base_name='%s%s%s') "
 565                                   "has share_file_id %llu but expected %llu"
 566                                   "==> do not cleanup\n",
 567                                   file_id_string(frame, &fid),
 568                                   data->servicepath,
 569                                   data->base_name,
 570                                   (data->stream_name == NULL)
 571                                   ? "" : "', stream_name='",
 572                                   (data->stream_name == NULL)
 573                                   ? "" : data->stream_name,
 574                                   (unsigned long long)entry->share_file_id,
 575                                   (unsigned long long)open_persistent_id));
 576                         goto done;
 577                 }
 578         }
 579
 580         ok = brl_cleanup_disconnected(fid, open_persistent_id);
 581         if (!ok) {
 582                 DEBUG(10, ("share_mode_cleanup_disconnected: "
 583                            "failed to clean up byte range locks associated "
 584                            "with file (file-id='%s', servicepath='%s', "
 585                            "base_name='%s%s%s') and open_persistent_id %llu "
 586                            "==> do not cleanup\n",
 587                            file_id_string(frame, &fid),
 588                            data->servicepath,
 589                            data->base_name,
 590                            (data->stream_name == NULL)
 591                            ? "" : "', stream_name='",
 592                            (data->stream_name == NULL)
 593                            ? "" : data->stream_name,
 594                            (unsigned long long)open_persistent_id));
 595                 goto done;
 596         }
 597
 598         DEBUG(10, ("share_mode_cleanup_disconnected: "
 599                    "cleaning up %u entries for file "
 600                    "(file-id='%s', servicepath='%s', "
 601                    "base_name='%s%s%s') "
 602                    "from open_persistent_id %llu\n",
 603                    data->num_share_modes,
 604                    file_id_string(frame, &fid),
 605                    data->servicepath,
 606                    data->base_name,
 607                    (data->stream_name == NULL)
 608                    ? "" : "', stream_name='",
 609                    (data->stream_name == NULL)
 610                    ? "" : data->stream_name,
 611                    (unsigned long long)open_persistent_id));
 612
 613         data->num_share_modes = 0;
 614         data->modified = true;
 615
 616         ret = true;
 617 done:
 618         talloc_free(frame);
 619         return ret;
 620 }