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         uint32_t i;
 175
 176         if (DEBUGLEVEL >= 10) {
 177                 DEBUG(10, ("unparse_share_modes:\n"));
 178                 NDR_PRINT_DEBUG(share_mode_data, d);
 179         }
 180
 181         i = 0;
 182         while (i < d->num_share_modes) {
 183                 if (d->share_modes[i].stale) {
 184                         /*
 185                          * Remove the stale entries before storing
 186                          */
 187                         struct share_mode_entry *m = d->share_modes;
 188                         m[i] = m[d->num_share_modes-1];
 189                         d->num_share_modes -= 1;
 190                 } else {
 191                         i += 1;
 192                 }
 193         }
 194
 195         if (d->num_share_modes == 0) {
 196                 DEBUG(10, ("No used share mode found\n"));
 197                 return make_tdb_data(NULL, 0);
 198         }
 199
 200         ndr_err = ndr_push_struct_blob(
 201                 &blob, d, d, (ndr_push_flags_fn_t)ndr_push_share_mode_data);
 202         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 203                 smb_panic("ndr_push_share_mode_lock failed");
 204         }
 205
 206         return make_tdb_data(blob.data, blob.length);
 207 }
 208
 209 /*******************************************************************
 210  If modified, store the share_mode_data back into the database.
 211 ********************************************************************/
 212
 213 static int share_mode_data_destructor(struct share_mode_data *d)
 214 {
 215         NTSTATUS status;
 216         TDB_DATA data;
 217
 218         if (!d->modified) {
 219                 return 0;
 220         }
 221
 222         data = unparse_share_modes(d);
 223
 224         if (data.dptr == NULL) {
 225                 if (!d->fresh) {
 226                         /* There has been an entry before, delete it */
 227
 228                         status = dbwrap_record_delete(d->record);
 229                         if (!NT_STATUS_IS_OK(status)) {
 230                                 char *errmsg;
 231
 232                                 DEBUG(0, ("delete_rec returned %s\n",
 233                                           nt_errstr(status)));
 234
 235                                 if (asprintf(&errmsg, "could not delete share "
 236                                              "entry: %s\n",
 237                                              nt_errstr(status)) == -1) {
 238                                         smb_panic("could not delete share"
 239                                                   "entry");
 240                                 }
 241                                 smb_panic(errmsg);
 242                         }
 243                 }
 244                 goto done;
 245         }
 246
 247         status = dbwrap_record_store(d->record, data, TDB_REPLACE);
 248         if (!NT_STATUS_IS_OK(status)) {
 249                 char *errmsg;
 250
 251                 DEBUG(0, ("store returned %s\n", nt_errstr(status)));
 252
 253                 if (asprintf(&errmsg, "could not store share mode entry: %s",
 254                              nt_errstr(status)) == -1) {
 255                         smb_panic("could not store share mode entry");
 256                 }
 257                 smb_panic(errmsg);
 258         }
 259
 260  done:
 261
 262         return 0;
 263 }
 264
 265 /*******************************************************************
 266  Allocate a new share_mode_data struct, mark it unmodified.
 267  fresh is set to note that currently there is no database entry.
 268 ********************************************************************/
 269
 270 static struct share_mode_data *fresh_share_mode_lock(
 271         TALLOC_CTX *mem_ctx, const char *servicepath,
 272         const struct smb_filename *smb_fname,
 273         const struct timespec *old_write_time)
 274 {
 275         struct share_mode_data *d;
 276
 277         if ((servicepath == NULL) || (smb_fname == NULL) ||
 278             (old_write_time == NULL)) {
 279                 return NULL;
 280         }
 281
 282         d = talloc_zero(mem_ctx, struct share_mode_data);
 283         if (d == NULL) {
 284                 goto fail;
 285         }
 286         d->base_name = talloc_strdup(d, smb_fname->base_name);
 287         if (d->base_name == NULL) {
 288                 goto fail;
 289         }
 290         if (smb_fname->stream_name != NULL) {
 291                 d->stream_name = talloc_strdup(d, smb_fname->stream_name);
 292                 if (d->stream_name == NULL) {
 293                         goto fail;
 294                 }
 295         }
 296         d->servicepath = talloc_strdup(d, servicepath);
 297         if (d->servicepath == NULL) {
 298                 goto fail;
 299         }
 300         d->old_write_time = *old_write_time;
 301         d->modified = false;
 302         d->fresh = true;
 303         return d;
 304 fail:
 305         DEBUG(0, ("talloc failed\n"));
 306         TALLOC_FREE(d);
 307         return NULL;
 308 }
 309
 310 /*******************************************************************
 311  Either fetch a share mode from the database, or allocate a fresh
 312  one if the record doesn't exist.
 313 ********************************************************************/
 314
 315 static struct share_mode_lock *get_share_mode_lock_internal(
 316         TALLOC_CTX *mem_ctx, struct file_id id,
 317         const char *servicepath, const struct smb_filename *smb_fname,
 318         const struct timespec *old_write_time)
 319 {
 320         struct share_mode_lock *lck;
 321         struct share_mode_data *d;
 322         struct db_record *rec;
 323         TDB_DATA key = locking_key(&id);
 324         TDB_DATA value;
 325
 326         rec = dbwrap_fetch_locked(lock_db, mem_ctx, key);
 327         if (rec == NULL) {
 328                 DEBUG(3, ("Could not lock share entry\n"));
 329                 return NULL;
 330         }
 331
 332         value = dbwrap_record_get_value(rec);
 333
 334         if (value.dptr == NULL) {
 335                 d = fresh_share_mode_lock(mem_ctx, servicepath, smb_fname,
 336                                           old_write_time);
 337         } else {
 338                 d = parse_share_modes(mem_ctx, value);
 339         }
 340
 341         if (d == NULL) {
 342                 DEBUG(5, ("get_share_mode_lock_internal: "
 343                         "Could not get share mode lock\n"));
 344                 TALLOC_FREE(rec);
 345                 return NULL;
 346         }
 347         d->id = id;
 348         d->record = talloc_move(d, &rec);
 349         talloc_set_destructor(d, share_mode_data_destructor);
 350
 351         lck = talloc(mem_ctx, struct share_mode_lock);
 352         if (lck == NULL) {
 353                 DEBUG(1, ("talloc failed\n"));
 354                 TALLOC_FREE(d);
 355                 return NULL;
 356         }
 357         lck->data = talloc_move(lck, &d);
 358         return lck;
 359 }
 360
 361 /*
 362  * We can only ever have one share mode locked. Users of
 363  * get_share_mode_lock never see this, it will be refcounted by
 364  * talloc_reference.
 365  */
 366 static struct share_mode_lock *the_lock;
 367
 368 static int the_lock_destructor(struct share_mode_lock *l)
 369 {
 370         the_lock = NULL;
 371         return 0;
 372 }
 373
 374 /*******************************************************************
 375  Get a share_mode_lock, Reference counted to allow nested calls.
 376 ********************************************************************/
 377
 378 struct share_mode_lock *get_share_mode_lock(
 379         TALLOC_CTX *mem_ctx,
 380         struct file_id id,
 381         const char *servicepath,
 382         const struct smb_filename *smb_fname,
 383         const struct timespec *old_write_time)
 384 {
 385         TALLOC_CTX *frame = talloc_stackframe();
 386
 387         struct share_mode_lock *lck;
 388
 389         if (the_lock == NULL) {
 390                 the_lock = get_share_mode_lock_internal(
 391                         frame, id, servicepath, smb_fname, old_write_time);
 392                 if (the_lock == NULL) {
 393                         goto fail;
 394                 }
 395                 talloc_set_destructor(the_lock, the_lock_destructor);
 396         }
 397         if (!file_id_equal(&the_lock->data->id, &id)) {
 398                 DEBUG(1, ("Can not lock two share modes simultaneously\n"));
 399                 goto fail;
 400         }
 401         lck = talloc(mem_ctx, struct share_mode_lock);
 402         if (lck == NULL) {
 403                 DEBUG(1, ("talloc failed\n"));
 404                 goto fail;
 405         }
 406         if (talloc_reference(lck, the_lock) == NULL) {
 407                 DEBUG(1, ("talloc_reference failed\n"));
 408                 goto fail;
 409         }
 410         lck->data = the_lock->data;
 411         TALLOC_FREE(frame);
 412         return lck;
 413 fail:
 414         TALLOC_FREE(frame);
 415         return NULL;
 416 }
 417
 418 static void fetch_share_mode_unlocked_parser(
 419         TDB_DATA key, TDB_DATA data, void *private_data)
 420 {
 421         struct share_mode_lock *lck = talloc_get_type_abort(
 422                 private_data, struct share_mode_lock);
 423
 424         lck->data = parse_share_modes(lck, data);
 425 }
 426
 427 /*******************************************************************
 428  Get a share_mode_lock without locking the database or reference
 429  counting. Used by smbstatus to display existing share modes.
 430 ********************************************************************/
 431
 432 struct share_mode_lock *fetch_share_mode_unlocked(TALLOC_CTX *mem_ctx,
 433                                                   struct file_id id)
 434 {
 435         struct share_mode_lock *lck;
 436         TDB_DATA key = locking_key(&id);
 437         NTSTATUS status;
 438
 439         lck = talloc(mem_ctx, struct share_mode_lock);
 440         if (lck == NULL) {
 441                 DEBUG(0, ("talloc failed\n"));
 442                 return NULL;
 443         }
 444         status = dbwrap_parse_record(
 445                 lock_db, key, fetch_share_mode_unlocked_parser, lck);
 446         if (!NT_STATUS_IS_OK(status) ||
 447             (lck->data == NULL)) {
 448                 TALLOC_FREE(lck);
 449                 return NULL;
 450         }
 451         return lck;
 452 }
 453
 454 struct forall_state {
 455         void (*fn)(const struct share_mode_entry *entry,
 456                    const char *sharepath,
 457                    const char *fname,
 458                    void *private_data);
 459         void *private_data;
 460 };
 461
 462 static int traverse_fn(struct db_record *rec, void *_state)
 463 {
 464         struct forall_state *state = (struct forall_state *)_state;
 465         uint32_t i;
 466         TDB_DATA key;
 467         TDB_DATA value;
 468         DATA_BLOB blob;
 469         enum ndr_err_code ndr_err;
 470         struct share_mode_data *d;
 471
 472         key = dbwrap_record_get_key(rec);
 473         value = dbwrap_record_get_value(rec);
 474
 475         /* Ensure this is a locking_key record. */
 476         if (key.dsize != sizeof(struct file_id))
 477                 return 0;
 478
 479         d = talloc(talloc_tos(), struct share_mode_data);
 480         if (d == NULL) {
 481                 return 0;
 482         }
 483
 484         blob.data = value.dptr;
 485         blob.length = value.dsize;
 486
 487         ndr_err = ndr_pull_struct_blob(
 488                 &blob, d, d, (ndr_pull_flags_fn_t)ndr_pull_share_mode_data);
 489         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 490                 DEBUG(1, ("ndr_pull_share_mode_lock failed\n"));
 491                 return 0;
 492         }
 493         if (DEBUGLEVEL > 10) {
 494                 DEBUG(11, ("parse_share_modes:\n"));
 495                 NDR_PRINT_DEBUG(share_mode_data, d);
 496         }
 497         for (i=0; i<d->num_share_modes; i++) {
 498                 state->fn(&d->share_modes[i],
 499                           d->servicepath, d->base_name,
 500                           state->private_data);
 501         }
 502         TALLOC_FREE(d);
 503
 504         return 0;
 505 }
 506
 507 /*******************************************************************
 508  Call the specified function on each entry under management by the
 509  share mode system.
 510 ********************************************************************/
 511
 512 int share_mode_forall(void (*fn)(const struct share_mode_entry *, const char *,
 513                                  const char *, void *),
 514                       void *private_data)
 515 {
 516         struct forall_state state;
 517         NTSTATUS status;
 518         int count;
 519
 520         if (lock_db == NULL)
 521                 return 0;
 522
 523         state.fn = fn;
 524         state.private_data = private_data;
 525
 526         status = dbwrap_traverse_read(lock_db, traverse_fn, (void *)&state,
 527                                       &count);
 528
 529         if (!NT_STATUS_IS_OK(status)) {
 530                 return -1;
 531         } else {
 532                 return count;
 533         }
 534 }
 535
 536 bool share_mode_cleanup_disconnected(struct file_id fid,
 537                                      uint64_t open_persistent_id)
 538 {
 539         bool ret = false;
 540         TALLOC_CTX *frame = talloc_stackframe();
 541         unsigned n;
 542         struct share_mode_data *data;
 543         struct share_mode_lock *lck;
 544         bool ok;
 545
 546         lck = get_existing_share_mode_lock(frame, fid);
 547         if (lck == NULL) {
 548                 DEBUG(5, ("share_mode_cleanup_disconnected: "
 549                           "Could not fetch share mode entry for %s\n",
 550                           file_id_string(frame, &fid)));
 551                 goto done;
 552         }
 553         data = lck->data;
 554
 555         for (n=0; n < data->num_share_modes; n++) {
 556                 struct share_mode_entry *entry = &data->share_modes[n];
 557
 558                 if (!server_id_is_disconnected(&entry->pid)) {
 559                         DEBUG(5, ("share_mode_cleanup_disconnected: "
 560                                   "file (file-id='%s', servicepath='%s', "
 561                                   "base_name='%s%s%s') "
 562                                   "is used by server %s ==> do not cleanup\n",
 563                                   file_id_string(frame, &fid),
 564                                   data->servicepath,
 565                                   data->base_name,
 566                                   (data->stream_name == NULL)
 567                                   ? "" : "', stream_name='",
 568                                   (data->stream_name == NULL)
 569                                   ? "" : data->stream_name,
 570                                   server_id_str(frame, &entry->pid)));
 571                         goto done;
 572                 }
 573                 if (open_persistent_id != entry->share_file_id) {
 574                         DEBUG(5, ("share_mode_cleanup_disconnected: "
 575                                   "entry for file "
 576                                   "(file-id='%s', servicepath='%s', "
 577                                   "base_name='%s%s%s') "
 578                                   "has share_file_id %llu but expected %llu"
 579                                   "==> do not cleanup\n",
 580                                   file_id_string(frame, &fid),
 581                                   data->servicepath,
 582                                   data->base_name,
 583                                   (data->stream_name == NULL)
 584                                   ? "" : "', stream_name='",
 585                                   (data->stream_name == NULL)
 586                                   ? "" : data->stream_name,
 587                                   (unsigned long long)entry->share_file_id,
 588                                   (unsigned long long)open_persistent_id));
 589                         goto done;
 590                 }
 591         }
 592
 593         ok = brl_cleanup_disconnected(fid, open_persistent_id);
 594         if (!ok) {
 595                 DEBUG(10, ("share_mode_cleanup_disconnected: "
 596                            "failed to clean up byte range locks associated "
 597                            "with file (file-id='%s', servicepath='%s', "
 598                            "base_name='%s%s%s') and open_persistent_id %llu "
 599                            "==> do not cleanup\n",
 600                            file_id_string(frame, &fid),
 601                            data->servicepath,
 602                            data->base_name,
 603                            (data->stream_name == NULL)
 604                            ? "" : "', stream_name='",
 605                            (data->stream_name == NULL)
 606                            ? "" : data->stream_name,
 607                            (unsigned long long)open_persistent_id));
 608                 goto done;
 609         }
 610
 611         DEBUG(10, ("share_mode_cleanup_disconnected: "
 612                    "cleaning up %u entries for file "
 613                    "(file-id='%s', servicepath='%s', "
 614                    "base_name='%s%s%s') "
 615                    "from open_persistent_id %llu\n",
 616                    data->num_share_modes,
 617                    file_id_string(frame, &fid),
 618                    data->servicepath,
 619                    data->base_name,
 620                    (data->stream_name == NULL)
 621                    ? "" : "', stream_name='",
 622                    (data->stream_name == NULL)
 623                    ? "" : data->stream_name,
 624                    (unsigned long long)open_persistent_id));
 625
 626         data->num_share_modes = 0;
 627         data->modified = true;
 628
 629         ret = true;
 630 done:
 631         talloc_free(frame);
 632         return ret;
 633 }