source3/lib/util_tdb.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    tdb utility functions
   4    Copyright (C) Andrew Tridgell   1992-1998
   5    Copyright (C) Rafal Szczesniak  2002
   6    Copyright (C) Michael Adam      2007
   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
  22 #include "includes.h"
  23 #undef malloc
  24 #undef realloc
  25 #undef calloc
  26 #undef strdup
  27
  28 /* these are little tdb utility functions that are meant to make
  29    dealing with a tdb database a little less cumbersome in Samba */
  30
  31 static SIG_ATOMIC_T gotalarm;
  32
  33 /***************************************************************
  34  Signal function to tell us we timed out.
  35 ****************************************************************/
  36
  37 static void gotalarm_sig(void)
  38 {
  39         gotalarm = 1;
  40 }
  41
  42 /****************************************************************************
  43  Lock a chain with timeout (in seconds).
  44 ****************************************************************************/
  45
  46 static int tdb_chainlock_with_timeout_internal( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout, int rw_type)
  47 {
  48         /* Allow tdb_chainlock to be interrupted by an alarm. */
  49         int ret;
  50         gotalarm = 0;
  51
  52         if (timeout) {
  53                 CatchSignal(SIGALRM, SIGNAL_CAST gotalarm_sig);
  54                 tdb_setalarm_sigptr(tdb, &gotalarm);
  55                 alarm(timeout);
  56         }
  57
  58         if (rw_type == F_RDLCK)
  59                 ret = tdb_chainlock_read(tdb, key);
  60         else
  61                 ret = tdb_chainlock(tdb, key);
  62
  63         if (timeout) {
  64                 alarm(0);
  65                 tdb_setalarm_sigptr(tdb, NULL);
  66                 CatchSignal(SIGALRM, SIGNAL_CAST SIG_IGN);
  67                 if (gotalarm) {
  68                         DEBUG(0,("tdb_chainlock_with_timeout_internal: alarm (%u) timed out for key %s in tdb %s\n",
  69                                 timeout, key.dptr, tdb_name(tdb)));
  70                         /* TODO: If we time out waiting for a lock, it might
  71                          * be nice to use F_GETLK to get the pid of the
  72                          * process currently holding the lock and print that
  73                          * as part of the debugging message. -- mbp */
  74                         return -1;
  75                 }
  76         }
  77
  78         return ret;
  79 }
  80
  81 /****************************************************************************
  82  Write lock a chain. Return -1 if timeout or lock failed.
  83 ****************************************************************************/
  84
  85 int tdb_chainlock_with_timeout( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout)
  86 {
  87         return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_WRLCK);
  88 }
  89
  90 int tdb_lock_bystring_with_timeout(TDB_CONTEXT *tdb, const char *keyval,
  91                                    int timeout)
  92 {
  93         TDB_DATA key = string_term_tdb_data(keyval);
  94
  95         return tdb_chainlock_with_timeout(tdb, key, timeout);
  96 }
  97
  98 /****************************************************************************
  99  Read lock a chain by string. Return -1 if timeout or lock failed.
 100 ****************************************************************************/
 101
 102 int tdb_read_lock_bystring_with_timeout(TDB_CONTEXT *tdb, const char *keyval, unsigned int timeout)
 103 {
 104         TDB_DATA key = string_term_tdb_data(keyval);
 105
 106         return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_RDLCK);
 107 }
 108
 109
 110
 111
 112 int tdb_trans_store_bystring(TDB_CONTEXT *tdb, const char *keystr,
 113                              TDB_DATA data, int flags)
 114 {
 115         TDB_DATA key = string_term_tdb_data(keystr);
 116
 117         return tdb_trans_store(tdb, key, data, flags);
 118 }
 119
 120 /****************************************************************************
 121  Useful pair of routines for packing/unpacking data consisting of
 122  integers and strings.
 123 ****************************************************************************/
 124
 125 static size_t tdb_pack_va(uint8 *buf, int bufsize, const char *fmt, va_list ap)
 126 {
 127         uint8 bt;
 128         uint16 w;
 129         uint32 d;
 130         int i;
 131         void *p;
 132         int len;
 133         char *s;
 134         char c;
 135         uint8 *buf0 = buf;
 136         const char *fmt0 = fmt;
 137         int bufsize0 = bufsize;
 138
 139         while (*fmt) {
 140                 switch ((c = *fmt++)) {
 141                 case 'b': /* unsigned 8-bit integer */
 142                         len = 1;
 143                         bt = (uint8)va_arg(ap, int);
 144                         if (bufsize && bufsize >= len)
 145                                 SSVAL(buf, 0, bt);
 146                         break;
 147                 case 'w': /* unsigned 16-bit integer */
 148                         len = 2;
 149                         w = (uint16)va_arg(ap, int);
 150                         if (bufsize && bufsize >= len)
 151                                 SSVAL(buf, 0, w);
 152                         break;
 153                 case 'd': /* signed 32-bit integer (standard int in most systems) */
 154                         len = 4;
 155                         d = va_arg(ap, uint32);
 156                         if (bufsize && bufsize >= len)
 157                                 SIVAL(buf, 0, d);
 158                         break;
 159                 case 'p': /* pointer */
 160                         len = 4;
 161                         p = va_arg(ap, void *);
 162                         d = p?1:0;
 163                         if (bufsize && bufsize >= len)
 164                                 SIVAL(buf, 0, d);
 165                         break;
 166                 case 'P': /* null-terminated string */
 167                         s = va_arg(ap,char *);
 168                         w = strlen(s);
 169                         len = w + 1;
 170                         if (bufsize && bufsize >= len)
 171                                 memcpy(buf, s, len);
 172                         break;
 173                 case 'f': /* null-terminated string */
 174                         s = va_arg(ap,char *);
 175                         w = strlen(s);
 176                         len = w + 1;
 177                         if (bufsize && bufsize >= len)
 178                                 memcpy(buf, s, len);
 179                         break;
 180                 case 'B': /* fixed-length string */
 181                         i = va_arg(ap, int);
 182                         s = va_arg(ap, char *);
 183                         len = 4+i;
 184                         if (bufsize && bufsize >= len) {
 185                                 SIVAL(buf, 0, i);
 186                                 memcpy(buf+4, s, i);
 187                         }
 188                         break;
 189                 default:
 190                         DEBUG(0,("Unknown tdb_pack format %c in %s\n",
 191                                  c, fmt));
 192                         len = 0;
 193                         break;
 194                 }
 195
 196                 buf += len;
 197                 if (bufsize)
 198                         bufsize -= len;
 199                 if (bufsize < 0)
 200                         bufsize = 0;
 201         }
 202
 203         DEBUG(18,("tdb_pack_va(%s, %d) -> %d\n",
 204                  fmt0, bufsize0, (int)PTR_DIFF(buf, buf0)));
 205
 206         return PTR_DIFF(buf, buf0);
 207 }
 208
 209 size_t tdb_pack(uint8 *buf, int bufsize, const char *fmt, ...)
 210 {
 211         va_list ap;
 212         size_t result;
 213
 214         va_start(ap, fmt);
 215         result = tdb_pack_va(buf, bufsize, fmt, ap);
 216         va_end(ap);
 217         return result;
 218 }
 219
 220 bool tdb_pack_append(TALLOC_CTX *mem_ctx, uint8 **buf, size_t *len,
 221                      const char *fmt, ...)
 222 {
 223         va_list ap;
 224         size_t len1, len2;
 225
 226         va_start(ap, fmt);
 227         len1 = tdb_pack_va(NULL, 0, fmt, ap);
 228         va_end(ap);
 229
 230         if (mem_ctx != NULL) {
 231                 *buf = TALLOC_REALLOC_ARRAY(mem_ctx, *buf, uint8,
 232                                             (*len) + len1);
 233         } else {
 234                 *buf = SMB_REALLOC_ARRAY(*buf, uint8, (*len) + len1);
 235         }
 236
 237         if (*buf == NULL) {
 238                 return False;
 239         }
 240
 241         va_start(ap, fmt);
 242         len2 = tdb_pack_va((*buf)+(*len), len1, fmt, ap);
 243         va_end(ap);
 244
 245         if (len1 != len2) {
 246                 return False;
 247         }
 248
 249         *len += len2;
 250
 251         return True;
 252 }
 253
 254 /****************************************************************************
 255  Useful pair of routines for packing/unpacking data consisting of
 256  integers and strings.
 257 ****************************************************************************/
 258
 259 int tdb_unpack(const uint8 *buf, int bufsize, const char *fmt, ...)
 260 {
 261         va_list ap;
 262         uint8 *bt;
 263         uint16 *w;
 264         uint32 *d;
 265         int len;
 266         int *i;
 267         void **p;
 268         char *s, **b, **ps;
 269         char c;
 270         const uint8 *buf0 = buf;
 271         const char *fmt0 = fmt;
 272         int bufsize0 = bufsize;
 273
 274         va_start(ap, fmt);
 275
 276         while (*fmt) {
 277                 switch ((c=*fmt++)) {
 278                 case 'b':
 279                         len = 1;
 280                         bt = va_arg(ap, uint8 *);
 281                         if (bufsize < len)
 282                                 goto no_space;
 283                         *bt = SVAL(buf, 0);
 284                         break;
 285                 case 'w':
 286                         len = 2;
 287                         w = va_arg(ap, uint16 *);
 288                         if (bufsize < len)
 289                                 goto no_space;
 290                         *w = SVAL(buf, 0);
 291                         break;
 292                 case 'd':
 293                         len = 4;
 294                         d = va_arg(ap, uint32 *);
 295                         if (bufsize < len)
 296                                 goto no_space;
 297                         *d = IVAL(buf, 0);
 298                         break;
 299                 case 'p':
 300                         len = 4;
 301                         p = va_arg(ap, void **);
 302                         if (bufsize < len)
 303                                 goto no_space;
 304                         /*
 305                          * This isn't a real pointer - only a token (1 or 0)
 306                          * to mark the fact a pointer is present.
 307                          */
 308
 309                         *p = (void *)(IVAL(buf, 0) ? (void *)1 : NULL);
 310                         break;
 311                 case 'P':
 312                         /* Return malloc'ed string. */
 313                         ps = va_arg(ap,char **);
 314                         len = strlen((const char *)buf) + 1;
 315                         *ps = SMB_STRDUP((const char *)buf);
 316                         break;
 317                 case 'f':
 318                         s = va_arg(ap,char *);
 319                         len = strlen((const char *)buf) + 1;
 320                         if (bufsize < len || len > sizeof(fstring))
 321                                 goto no_space;
 322                         memcpy(s, buf, len);
 323                         break;
 324                 case 'B':
 325                         i = va_arg(ap, int *);
 326                         b = va_arg(ap, char **);
 327                         len = 4;
 328                         if (bufsize < len)
 329                                 goto no_space;
 330                         *i = IVAL(buf, 0);
 331                         if (! *i) {
 332                                 *b = NULL;
 333                                 break;
 334                         }
 335                         len += *i;
 336                         if (bufsize < len)
 337                                 goto no_space;
 338                         *b = (char *)SMB_MALLOC(*i);
 339                         if (! *b)
 340                                 goto no_space;
 341                         memcpy(*b, buf+4, *i);
 342                         break;
 343                 default:
 344                         DEBUG(0,("Unknown tdb_unpack format %c in %s\n",
 345                                  c, fmt));
 346
 347                         len = 0;
 348                         break;
 349                 }
 350
 351                 buf += len;
 352                 bufsize -= len;
 353         }
 354
 355         va_end(ap);
 356
 357         DEBUG(18,("tdb_unpack(%s, %d) -> %d\n",
 358                  fmt0, bufsize0, (int)PTR_DIFF(buf, buf0)));
 359
 360         return PTR_DIFF(buf, buf0);
 361
 362  no_space:
 363         va_end(ap);
 364         return -1;
 365 }
 366
 367
 368 /****************************************************************************
 369  Log tdb messages via DEBUG().
 370 ****************************************************************************/
 371
 372 static void tdb_log(TDB_CONTEXT *tdb, enum tdb_debug_level level, const char *format, ...)
 373 {
 374         va_list ap;
 375         char *ptr = NULL;
 376         int ret;
 377
 378         va_start(ap, format);
 379         ret = vasprintf(&ptr, format, ap);
 380         va_end(ap);
 381
 382         if ((ret == -1) || !*ptr)
 383                 return;
 384
 385         DEBUG((int)level, ("tdb(%s): %s", tdb_name(tdb) ? tdb_name(tdb) : "unnamed", ptr));
 386         SAFE_FREE(ptr);
 387 }
 388
 389 /****************************************************************************
 390  Like tdb_open() but also setup a logging function that redirects to
 391  the samba DEBUG() system.
 392 ****************************************************************************/
 393
 394 TDB_CONTEXT *tdb_open_log(const char *name, int hash_size, int tdb_flags,
 395                           int open_flags, mode_t mode)
 396 {
 397         TDB_CONTEXT *tdb;
 398         struct tdb_logging_context log_ctx;
 399
 400         if (!lp_use_mmap())
 401                 tdb_flags |= TDB_NOMMAP;
 402
 403         log_ctx.log_fn = tdb_log;
 404         log_ctx.log_private = NULL;
 405
 406         if ((hash_size == 0) && (name != NULL)) {
 407                 const char *base = strrchr_m(name, '/');
 408                 if (base != NULL) {
 409                         base += 1;
 410                 }
 411                 else {
 412                         base = name;
 413                 }
 414                 hash_size = lp_parm_int(-1, "tdb_hashsize", base, 0);
 415         }
 416
 417         tdb = tdb_open_ex(name, hash_size, tdb_flags,
 418                           open_flags, mode, &log_ctx, NULL);
 419         if (!tdb)
 420                 return NULL;
 421
 422         return tdb;
 423 }
 424
 425
 426 /**
 427  * Search across the whole tdb for keys that match the given pattern
 428  * return the result as a list of keys
 429  *
 430  * @param tdb pointer to opened tdb file context
 431  * @param pattern searching pattern used by fnmatch(3) functions
 432  *
 433  * @return list of keys found by looking up with given pattern
 434  **/
 435 TDB_LIST_NODE *tdb_search_keys(TDB_CONTEXT *tdb, const char* pattern)
 436 {
 437         TDB_DATA key, next;
 438         TDB_LIST_NODE *list = NULL;
 439         TDB_LIST_NODE *rec = NULL;
 440
 441         for (key = tdb_firstkey(tdb); key.dptr; key = next) {
 442                 /* duplicate key string to ensure null-termination */
 443                 char *key_str = SMB_STRNDUP((const char *)key.dptr, key.dsize);
 444                 if (!key_str) {
 445                         DEBUG(0, ("tdb_search_keys: strndup() failed!\n"));
 446                         smb_panic("strndup failed!\n");
 447                 }
 448
 449                 DEBUG(18, ("checking %s for match to pattern %s\n", key_str, pattern));
 450
 451                 next = tdb_nextkey(tdb, key);
 452
 453                 /* do the pattern checking */
 454                 if (fnmatch(pattern, key_str, 0) == 0) {
 455                         rec = SMB_MALLOC_P(TDB_LIST_NODE);
 456                         ZERO_STRUCTP(rec);
 457
 458                         rec->node_key = key;
 459
 460                         DLIST_ADD_END(list, rec, TDB_LIST_NODE *);
 461
 462                         DEBUG(18, ("checking %s matched pattern %s\n", key_str, pattern));
 463                 } else {
 464                         free(key.dptr);
 465                 }
 466
 467                 /* free duplicated key string */
 468                 free(key_str);
 469         }
 470
 471         return list;
 472
 473 }
 474
 475
 476 /**
 477  * Free the list returned by tdb_search_keys
 478  *
 479  * @param node list of results found by tdb_search_keys
 480  **/
 481 void tdb_search_list_free(TDB_LIST_NODE* node)
 482 {
 483         TDB_LIST_NODE *next_node;
 484
 485         while (node) {
 486                 next_node = node->next;
 487                 SAFE_FREE(node->node_key.dptr);
 488                 SAFE_FREE(node);
 489                 node = next_node;
 490         };
 491 }
 492
 493 /****************************************************************************
 494  tdb_store, wrapped in a transaction. This way we make sure that a process
 495  that dies within writing does not leave a corrupt tdb behind.
 496 ****************************************************************************/
 497
 498 int tdb_trans_store(struct tdb_context *tdb, TDB_DATA key, TDB_DATA dbuf,
 499                     int flag)
 500 {
 501         int res;
 502
 503         if ((res = tdb_transaction_start(tdb)) != 0) {
 504                 DEBUG(5, ("tdb_transaction_start failed\n"));
 505                 return res;
 506         }
 507
 508         if ((res = tdb_store(tdb, key, dbuf, flag)) != 0) {
 509                 DEBUG(10, ("tdb_store failed\n"));
 510                 if (tdb_transaction_cancel(tdb) != 0) {
 511                         smb_panic("Cancelling transaction failed");
 512                 }
 513                 return res;
 514         }
 515
 516         if ((res = tdb_transaction_commit(tdb)) != 0) {
 517                 DEBUG(5, ("tdb_transaction_commit failed\n"));
 518         }
 519
 520         return res;
 521 }
 522
 523 /****************************************************************************
 524  tdb_delete, wrapped in a transaction. This way we make sure that a process
 525  that dies within deleting does not leave a corrupt tdb behind.
 526 ****************************************************************************/
 527
 528 int tdb_trans_delete(struct tdb_context *tdb, TDB_DATA key)
 529 {
 530         int res;
 531
 532         if ((res = tdb_transaction_start(tdb)) != 0) {
 533                 DEBUG(5, ("tdb_transaction_start failed\n"));
 534                 return res;
 535         }
 536
 537         if ((res = tdb_delete(tdb, key)) != 0) {
 538                 DEBUG(10, ("tdb_delete failed\n"));
 539                 if (tdb_transaction_cancel(tdb) != 0) {
 540                         smb_panic("Cancelling transaction failed");
 541                 }
 542                 return res;
 543         }
 544
 545         if ((res = tdb_transaction_commit(tdb)) != 0) {
 546                 DEBUG(5, ("tdb_transaction_commit failed\n"));
 547         }
 548
 549         return res;
 550 }
 551
 552 /*
 553  Log tdb messages via DEBUG().
 554 */
 555 static void tdb_wrap_log(TDB_CONTEXT *tdb, enum tdb_debug_level level,
 556                          const char *format, ...) PRINTF_ATTRIBUTE(3,4);
 557
 558 static void tdb_wrap_log(TDB_CONTEXT *tdb, enum tdb_debug_level level,
 559                          const char *format, ...)
 560 {
 561         va_list ap;
 562         char *ptr = NULL;
 563         int debuglevel = 0;
 564         int ret;
 565
 566         switch (level) {
 567         case TDB_DEBUG_FATAL:
 568                 debuglevel = 0;
 569                 break;
 570         case TDB_DEBUG_ERROR:
 571                 debuglevel = 1;
 572                 break;
 573         case TDB_DEBUG_WARNING:
 574                 debuglevel = 2;
 575                 break;
 576         case TDB_DEBUG_TRACE:
 577                 debuglevel = 5;
 578                 break;
 579         default:
 580                 debuglevel = 0;
 581         }
 582
 583         va_start(ap, format);
 584         ret = vasprintf(&ptr, format, ap);
 585         va_end(ap);
 586
 587         if (ret != -1) {
 588                 const char *name = tdb_name(tdb);
 589                 DEBUG(debuglevel, ("tdb(%s): %s", name ? name : "unnamed", ptr));
 590                 free(ptr);
 591         }
 592 }
 593
 594 static struct tdb_wrap *tdb_list;
 595
 596 /* destroy the last connection to a tdb */
 597 static int tdb_wrap_destructor(struct tdb_wrap *w)
 598 {
 599         tdb_close(w->tdb);
 600         DLIST_REMOVE(tdb_list, w);
 601         return 0;
 602 }
 603
 604 /*
 605   wrapped connection to a tdb database
 606   to close just talloc_free() the tdb_wrap pointer
 607  */
 608 struct tdb_wrap *tdb_wrap_open(TALLOC_CTX *mem_ctx,
 609                                const char *name, int hash_size, int tdb_flags,
 610                                int open_flags, mode_t mode)
 611 {
 612         struct tdb_wrap *w;
 613         struct tdb_logging_context log_ctx;
 614         log_ctx.log_fn = tdb_wrap_log;
 615
 616         if (!lp_use_mmap())
 617                 tdb_flags |= TDB_NOMMAP;
 618
 619         for (w=tdb_list;w;w=w->next) {
 620                 if (strcmp(name, w->name) == 0) {
 621                         /*
 622                          * Yes, talloc_reference is exactly what we want
 623                          * here. Otherwise we would have to implement our own
 624                          * reference counting.
 625                          */
 626                         return talloc_reference(mem_ctx, w);
 627                 }
 628         }
 629
 630         w = talloc(mem_ctx, struct tdb_wrap);
 631         if (w == NULL) {
 632                 return NULL;
 633         }
 634
 635         if (!(w->name = talloc_strdup(w, name))) {
 636                 talloc_free(w);
 637                 return NULL;
 638         }
 639
 640         if ((hash_size == 0) && (name != NULL)) {
 641                 const char *base = strrchr_m(name, '/');
 642                 if (base != NULL) {
 643                         base += 1;
 644                 }
 645                 else {
 646                         base = name;
 647                 }
 648                 hash_size = lp_parm_int(-1, "tdb_hashsize", base, 0);
 649         }
 650
 651         w->tdb = tdb_open_ex(name, hash_size, tdb_flags,
 652                              open_flags, mode, &log_ctx, NULL);
 653         if (w->tdb == NULL) {
 654                 talloc_free(w);
 655                 return NULL;
 656         }
 657
 658         talloc_set_destructor(w, tdb_wrap_destructor);
 659
 660         DLIST_ADD(tdb_list, w);
 661
 662         return w;
 663 }
 664
 665 NTSTATUS map_nt_error_from_tdb(enum TDB_ERROR err)
 666 {
 667         struct { enum TDB_ERROR err; NTSTATUS status; } map[] =
 668                 { { TDB_SUCCESS,        NT_STATUS_OK },
 669                   { TDB_ERR_CORRUPT,    NT_STATUS_INTERNAL_DB_CORRUPTION },
 670                   { TDB_ERR_IO,         NT_STATUS_UNEXPECTED_IO_ERROR },
 671                   { TDB_ERR_OOM,        NT_STATUS_NO_MEMORY },
 672                   { TDB_ERR_EXISTS,     NT_STATUS_OBJECT_NAME_COLLISION },
 673
 674                   /*
 675                    * TDB_ERR_LOCK is very broad, we could for example
 676                    * distinguish between fcntl locks and invalid lock
 677                    * sequences. So NT_STATUS_FILE_LOCK_CONFLICT is a
 678                    * compromise.
 679                    */
 680                   { TDB_ERR_LOCK,       NT_STATUS_FILE_LOCK_CONFLICT },
 681                   /*
 682                    * The next two ones in the enum are not actually used
 683                    */
 684                   { TDB_ERR_NOLOCK,     NT_STATUS_FILE_LOCK_CONFLICT },
 685                   { TDB_ERR_LOCK_TIMEOUT, NT_STATUS_FILE_LOCK_CONFLICT },
 686                   { TDB_ERR_NOEXIST,    NT_STATUS_NOT_FOUND },
 687                   { TDB_ERR_EINVAL,     NT_STATUS_INVALID_PARAMETER },
 688                   { TDB_ERR_RDONLY,     NT_STATUS_ACCESS_DENIED }
 689                 };
 690
 691         int i;
 692
 693         for (i=0; i < sizeof(map) / sizeof(map[0]); i++) {
 694                 if (err == map[i].err) {
 695                         return map[i].status;
 696                 }
 697         }
 698
 699         return NT_STATUS_INTERNAL_ERROR;
 700 }
 701
 702
 703 /*********************************************************************
 704  * the following is a generic validation mechanism for tdbs.
 705  *********************************************************************/
 706
 707 /*
 708  * internal validation function, executed by the child.
 709  */
 710 static int tdb_validate_child(struct tdb_context *tdb,
 711                               tdb_validate_data_func validate_fn)
 712 {
 713         int ret = 1;
 714         int num_entries = 0;
 715         struct tdb_validation_status v_status;
 716
 717         v_status.tdb_error = False;
 718         v_status.bad_freelist = False;
 719         v_status.bad_entry = False;
 720         v_status.unknown_key = False;
 721         v_status.success = True;
 722
 723         if (!tdb) {
 724                 v_status.tdb_error = True;
 725                 v_status.success = False;
 726                 goto out;
 727         }
 728
 729         /* Check if the tdb's freelist is good. */
 730         if (tdb_validate_freelist(tdb, &num_entries) == -1) {
 731                 v_status.bad_freelist = True;
 732                 v_status.success = False;
 733                 goto out;
 734         }
 735
 736         DEBUG(10,("tdb_validate_child: tdb %s freelist has %d entries\n",
 737                   tdb_name(tdb), num_entries));
 738
 739         /* Now traverse the tdb to validate it. */
 740         num_entries = tdb_traverse(tdb, validate_fn, (void *)&v_status);
 741         if (!v_status.success) {
 742                 goto out;
 743         } else if (num_entries == -1) {
 744                 v_status.tdb_error = True;
 745                 v_status.success = False;
 746                 goto out;
 747         }
 748
 749         DEBUG(10,("tdb_validate_child: tdb %s is good with %d entries\n",
 750                   tdb_name(tdb), num_entries));
 751         ret = 0; /* Cache is good. */
 752
 753 out:
 754         DEBUG(10,   ("tdb_validate_child: summary of validation status:\n"));
 755         DEBUGADD(10,(" * tdb error: %s\n", v_status.tdb_error ? "yes" : "no"));
 756         DEBUGADD(10,(" * bad freelist: %s\n",v_status.bad_freelist?"yes":"no"));
 757         DEBUGADD(10,(" * bad entry: %s\n", v_status.bad_entry ? "yes" : "no"));
 758         DEBUGADD(10,(" * unknown key: %s\n", v_status.unknown_key?"yes":"no"));
 759         DEBUGADD(10,(" => overall success: %s\n", v_status.success?"yes":"no"));
 760
 761         return ret;
 762 }
 763
 764 /*
 765  * tdb validation function.
 766  * returns 0 if tdb is ok, != 0 if it isn't.
 767  * this function expects an opened tdb.
 768  */
 769 int tdb_validate(struct tdb_context *tdb, tdb_validate_data_func validate_fn)
 770 {
 771         pid_t child_pid = -1;
 772         int child_status = 0;
 773         int wait_pid = 0;
 774         int ret = 1;
 775
 776         if (tdb == NULL) {
 777                 DEBUG(1, ("Error: tdb_validate called with tdb == NULL\n"));
 778                 return ret;
 779         }
 780
 781         DEBUG(5, ("tdb_validate called for tdb '%s'\n", tdb_name(tdb)));
 782
 783         /* fork and let the child do the validation.
 784          * benefit: no need to twist signal handlers and panic functions.
 785          * just let the child panic. we catch the signal. */
 786
 787         DEBUG(10, ("tdb_validate: forking to let child do validation.\n"));
 788         child_pid = sys_fork();
 789         if (child_pid == 0) {
 790                 /* child code */
 791                 DEBUG(10, ("tdb_validate (validation child): created\n"));
 792                 DEBUG(10, ("tdb_validate (validation child): "
 793                            "calling tdb_validate_child\n"));
 794                 exit(tdb_validate_child(tdb, validate_fn));
 795         }
 796         else if (child_pid < 0) {
 797                 DEBUG(1, ("tdb_validate: fork for validation failed.\n"));
 798                 goto done;
 799         }
 800
 801         /* parent */
 802
 803         DEBUG(10, ("tdb_validate: fork succeeded, child PID = %d\n",child_pid));
 804
 805         DEBUG(10, ("tdb_validate: waiting for child to finish...\n"));
 806         while  ((wait_pid = sys_waitpid(child_pid, &child_status, 0)) < 0) {
 807                 if (errno == EINTR) {
 808                         DEBUG(10, ("tdb_validate: got signal during waitpid, "
 809                                    "retrying\n"));
 810                         errno = 0;
 811                         continue;
 812                 }
 813                 DEBUG(1, ("tdb_validate: waitpid failed with error '%s'.\n",
 814                           strerror(errno)));
 815                 goto done;
 816         }
 817         if (wait_pid != child_pid) {
 818                 DEBUG(1, ("tdb_validate: waitpid returned pid %d, "
 819                           "but %d was expected\n", wait_pid, child_pid));
 820                 goto done;
 821         }
 822
 823         DEBUG(10, ("tdb_validate: validating child returned.\n"));
 824         if (WIFEXITED(child_status)) {
 825                 DEBUG(10, ("tdb_validate: child exited, code %d.\n",
 826                            WEXITSTATUS(child_status)));
 827                 ret = WEXITSTATUS(child_status);
 828         }
 829         if (WIFSIGNALED(child_status)) {
 830                 DEBUG(10, ("tdb_validate: child terminated by signal %d\n",
 831                            WTERMSIG(child_status)));
 832 #ifdef WCOREDUMP
 833                 if (WCOREDUMP(child_status)) {
 834                         DEBUGADD(10, ("core dumped\n"));
 835                 }
 836 #endif
 837                 ret = WTERMSIG(child_status);
 838         }
 839         if (WIFSTOPPED(child_status)) {
 840                 DEBUG(10, ("tdb_validate: child was stopped by signal %d\n",
 841                            WSTOPSIG(child_status)));
 842                 ret = WSTOPSIG(child_status);
 843         }
 844
 845 done:
 846         DEBUG(5, ("tdb_validate returning code '%d' for tdb '%s'\n", ret,
 847                   tdb_name(tdb)));
 848
 849         return ret;
 850 }
 851
 852 /*
 853  * tdb validation function.
 854  * returns 0 if tdb is ok, != 0 if it isn't.
 855  * this is a wrapper around the actual validation function that opens and closes
 856  * the tdb.
 857  */
 858 int tdb_validate_open(const char *tdb_path, tdb_validate_data_func validate_fn)
 859 {
 860         TDB_CONTEXT *tdb = NULL;
 861         int ret = 1;
 862
 863         DEBUG(5, ("tdb_validate_open called for tdb '%s'\n", tdb_path));
 864
 865         tdb = tdb_open_log(tdb_path, 0, TDB_DEFAULT, O_RDONLY, 0);
 866         if (!tdb) {
 867                 DEBUG(1, ("Error opening tdb %s\n", tdb_path));
 868                 return ret;
 869         }
 870
 871         ret = tdb_validate(tdb, validate_fn);
 872         tdb_close(tdb);
 873         return ret;
 874 }
 875
 876 /*
 877  * tdb backup function and helpers for tdb_validate wrapper with backup
 878  * handling.
 879  */
 880
 881 /* this structure eliminates the need for a global overall status for
 882  * the traverse-copy */
 883 struct tdb_copy_data {
 884         struct tdb_context *dst;
 885         bool success;
 886 };
 887
 888 static int traverse_copy_fn(struct tdb_context *tdb, TDB_DATA key,
 889                             TDB_DATA dbuf, void *private_data)
 890 {
 891         struct tdb_copy_data *data = (struct tdb_copy_data *)private_data;
 892
 893         if (tdb_store(data->dst, key, dbuf, TDB_INSERT) != 0) {
 894                 DEBUG(4, ("Failed to insert into %s: %s\n", tdb_name(data->dst),
 895                           strerror(errno)));
 896                 data->success = False;
 897                 return 1;
 898         }
 899         return 0;
 900 }
 901
 902 static int tdb_copy(struct tdb_context *src, struct tdb_context *dst)
 903 {
 904         struct tdb_copy_data data;
 905         int count;
 906
 907         data.dst = dst;
 908         data.success = True;
 909
 910         count = tdb_traverse(src, traverse_copy_fn, (void *)(&data));
 911         if ((count < 0) || (data.success == False)) {
 912                 return -1;
 913         }
 914         return count;
 915 }
 916
 917 static int tdb_verify_basic(struct tdb_context *tdb)
 918 {
 919         return tdb_traverse(tdb, NULL, NULL);
 920 }
 921
 922 /* this backup function is essentially taken from lib/tdb/tools/tdbbackup.tdb
 923  */
 924 static int tdb_backup(TALLOC_CTX *ctx, const char *src_path,
 925                       const char *dst_path, int hash_size)
 926 {
 927         struct tdb_context *src_tdb = NULL;
 928         struct tdb_context *dst_tdb = NULL;
 929         char *tmp_path = NULL;
 930         struct stat st;
 931         int count1, count2;
 932         int saved_errno = 0;
 933         int ret = -1;
 934
 935         if (stat(src_path, &st) != 0) {
 936                 DEBUG(3, ("Could not stat '%s': %s\n", src_path,
 937                           strerror(errno)));
 938                 goto done;
 939         }
 940
 941         /* open old tdb RDWR - so we can lock it */
 942         src_tdb = tdb_open_log(src_path, 0, TDB_DEFAULT, O_RDWR, 0);
 943         if (src_tdb == NULL) {
 944                 DEBUG(3, ("Failed to open tdb '%s'\n", src_path));
 945                 goto done;
 946         }
 947
 948         if (tdb_lockall(src_tdb) != 0) {
 949                 DEBUG(3, ("Failed to lock tdb '%s'\n", src_path));
 950                 goto done;
 951         }
 952
 953         tmp_path = talloc_asprintf(ctx, "%s%s", dst_path, ".tmp");
 954         unlink(tmp_path);
 955         dst_tdb = tdb_open_log(tmp_path,
 956                                hash_size ? hash_size : tdb_hash_size(src_tdb),
 957                                TDB_DEFAULT, O_RDWR | O_CREAT | O_EXCL,
 958                                st.st_mode & 0777);
 959         if (dst_tdb == NULL) {
 960                 DEBUG(3, ("Error creating tdb '%s': %s\n", tmp_path,
 961                           strerror(errno)));
 962                 saved_errno = errno;
 963                 unlink(tmp_path);
 964                 goto done;
 965         }
 966
 967         count1 = tdb_copy(src_tdb, dst_tdb);
 968         if (count1 < 0) {
 969                 DEBUG(3, ("Failed to copy tdb '%s': %s\n", src_path,
 970                           strerror(errno)));
 971                 tdb_close(dst_tdb);
 972                 goto done;
 973         }
 974
 975         /* reopen ro and do basic verification */
 976         tdb_close(dst_tdb);
 977         dst_tdb = tdb_open_log(tmp_path, 0, TDB_DEFAULT, O_RDONLY, 0);
 978         if (!dst_tdb) {
 979                 DEBUG(3, ("Failed to reopen tdb '%s': %s\n", tmp_path,
 980                           strerror(errno)));
 981                 goto done;
 982         }
 983         count2 = tdb_verify_basic(dst_tdb);
 984         if (count2 != count1) {
 985                 DEBUG(3, ("Failed to verify result of copying tdb '%s'.\n",
 986                           src_path));
 987                 tdb_close(dst_tdb);
 988                 goto done;
 989         }
 990
 991         DEBUG(10, ("tdb_backup: successfully copied %d entries\n", count1));
 992
 993         /* make sure the new tdb has reached stable storage
 994          * then rename it to its destination */
 995         fsync(tdb_fd(dst_tdb));
 996         tdb_close(dst_tdb);
 997         unlink(dst_path);
 998         if (rename(tmp_path, dst_path) != 0) {
 999                 DEBUG(3, ("Failed to rename '%s' to '%s': %s\n",
1000                           tmp_path, dst_path, strerror(errno)));
1001                 goto done;
1002         }
1003
1004         /* success */
1005         ret = 0;
1006
1007 done:
1008         if (src_tdb != NULL) {
1009                 tdb_close(src_tdb);
1010         }
1011         if (tmp_path != NULL) {
1012                 unlink(tmp_path);
1013                 TALLOC_FREE(tmp_path);
1014         }
1015         if (saved_errno != 0) {
1016                 errno = saved_errno;
1017         }
1018         return ret;
1019 }
1020
1021 static int rename_file_with_suffix(TALLOC_CTX *ctx, const char *path,
1022                                    const char *suffix)
1023 {
1024         int ret = -1;
1025         char *dst_path;
1026
1027         dst_path = talloc_asprintf(ctx, "%s%s", path, suffix);
1028
1029         ret = (rename(path, dst_path) != 0);
1030
1031         if (ret == 0) {
1032                 DEBUG(5, ("moved '%s' to '%s'\n", path, dst_path));
1033         } else if (errno == ENOENT) {
1034                 DEBUG(3, ("file '%s' does not exist - so not moved\n", path));
1035                 ret = 0;
1036         } else {
1037                 DEBUG(3, ("error renaming %s to %s: %s\n", path, dst_path,
1038                           strerror(errno)));
1039         }
1040
1041         TALLOC_FREE(dst_path);
1042         return ret;
1043 }
1044
1045 /*
1046  * do a backup of a tdb, moving the destination out of the way first
1047  */
1048 static int tdb_backup_with_rotate(TALLOC_CTX *ctx, const char *src_path,
1049                                   const char *dst_path, int hash_size,
1050                                   const char *rotate_suffix,
1051                                   bool retry_norotate_if_nospc,
1052                                   bool rename_as_last_resort_if_nospc)
1053 {
1054         int ret;
1055
1056         rename_file_with_suffix(ctx, dst_path, rotate_suffix);
1057
1058         ret = tdb_backup(ctx, src_path, dst_path, hash_size);
1059
1060         if (ret != 0) {
1061                 DEBUG(10, ("backup of %s failed: %s\n", src_path, strerror(errno)));
1062         }
1063         if ((ret != 0) && (errno == ENOSPC) && retry_norotate_if_nospc)
1064         {
1065                 char *rotate_path = talloc_asprintf(ctx, "%s%s", dst_path,
1066                                                     rotate_suffix);
1067                 DEBUG(10, ("backup of %s failed due to lack of space\n",
1068                            src_path));
1069                 DEBUGADD(10, ("trying to free some space by removing rotated "
1070                               "dst %s\n", rotate_path));
1071                 if (unlink(rotate_path) == -1) {
1072                         DEBUG(10, ("unlink of %s failed: %s\n", rotate_path,
1073                                    strerror(errno)));
1074                 } else {
1075                         ret = tdb_backup(ctx, src_path, dst_path, hash_size);
1076                 }
1077                 TALLOC_FREE(rotate_path);
1078         }
1079
1080         if ((ret != 0) && (errno == ENOSPC) && rename_as_last_resort_if_nospc)
1081         {
1082                 DEBUG(10, ("backup of %s failed due to lack of space\n",
1083                            src_path));
1084                 DEBUGADD(10, ("using 'rename' as a last resort\n"));
1085                 ret = rename(src_path, dst_path);
1086         }
1087
1088         return ret;
1089 }
1090
1091 /*
1092  * validation function with backup handling:
1093  *
1094  *  - calls tdb_validate
1095  *  - if the tdb is ok, create a backup "name.bak", possibly moving
1096  *    existing backup to name.bak.old,
1097  *    return 0 (success) even if the backup fails
1098  *  - if the tdb is corrupt:
1099  *    - move the tdb to "name.corrupt"
1100  *    - check if there is valid backup.
1101  *      if so, restore the backup.
1102  *      if restore is successful, return 0 (success),
1103  *    - otherwise return -1 (failure)
1104  */
1105 int tdb_validate_and_backup(const char *tdb_path,
1106                             tdb_validate_data_func validate_fn)
1107 {
1108         int ret = -1;
1109         const char *backup_suffix = ".bak";
1110         const char *corrupt_suffix = ".corrupt";
1111         const char *rotate_suffix = ".old";
1112         char *tdb_path_backup;
1113         struct stat st;
1114         TALLOC_CTX *ctx = NULL;
1115
1116         ctx = talloc_new(NULL);
1117         if (ctx == NULL) {
1118                 DEBUG(0, ("tdb_validate_and_backup: out of memory\n"));
1119                 goto done;
1120         }
1121
1122         tdb_path_backup = talloc_asprintf(ctx, "%s%s", tdb_path, backup_suffix);
1123
1124         ret = tdb_validate_open(tdb_path, validate_fn);
1125
1126         if (ret == 0) {
1127                 DEBUG(1, ("tdb '%s' is valid\n", tdb_path));
1128                 ret = tdb_backup_with_rotate(ctx, tdb_path, tdb_path_backup, 0,
1129                                              rotate_suffix, True, False);
1130                 if (ret != 0) {
1131                         DEBUG(1, ("Error creating backup of tdb '%s'\n",
1132                                   tdb_path));
1133                         /* the actual validation was successful: */
1134                         ret = 0;
1135                 } else {
1136                         DEBUG(1, ("Created backup '%s' of tdb '%s'\n",
1137                                   tdb_path_backup, tdb_path));
1138                 }
1139         } else {
1140                 DEBUG(1, ("tdb '%s' is invalid\n", tdb_path));
1141
1142                 ret =stat(tdb_path_backup, &st);
1143                 if (ret != 0) {
1144                         DEBUG(5, ("Could not stat '%s': %s\n", tdb_path_backup,
1145                                   strerror(errno)));
1146                         DEBUG(1, ("No backup found.\n"));
1147                 } else {
1148                         DEBUG(1, ("backup '%s' found.\n", tdb_path_backup));
1149                         ret = tdb_validate_open(tdb_path_backup, validate_fn);
1150                         if (ret != 0) {
1151                                 DEBUG(1, ("Backup '%s' is invalid.\n",
1152                                           tdb_path_backup));
1153                         }
1154                 }
1155
1156                 if (ret != 0) {
1157                         int renamed = rename_file_with_suffix(ctx, tdb_path,
1158                                                               corrupt_suffix);
1159                         if (renamed != 0) {
1160                                 DEBUG(1, ("Error moving tdb to '%s%s'\n",
1161                                           tdb_path, corrupt_suffix));
1162                         } else {
1163                                 DEBUG(1, ("Corrupt tdb stored as '%s%s'\n",
1164                                           tdb_path, corrupt_suffix));
1165                         }
1166                         goto done;
1167                 }
1168
1169                 DEBUG(1, ("valid backup '%s' found\n", tdb_path_backup));
1170                 ret = tdb_backup_with_rotate(ctx, tdb_path_backup, tdb_path, 0,
1171                                              corrupt_suffix, True, True);
1172                 if (ret != 0) {
1173                         DEBUG(1, ("Error restoring backup from '%s'\n",
1174                                   tdb_path_backup));
1175                 } else {
1176                         DEBUG(1, ("Restored tdb backup from '%s'\n",
1177                                   tdb_path_backup));
1178                 }
1179         }
1180
1181 done:
1182         TALLOC_FREE(ctx);
1183         return ret;
1184 }