git.ozlabs.org Git - ccan/blob - ccan/tdb2/check.c

   1  /*
   2    Trivial Database 2: free list/block handling
   3    Copyright (C) Rusty Russell 2010
   4
   5    This library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 3 of the License, or (at your option) any later version.
   9
  10    This library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17 */
  18 #include "private.h"
  19 #include <ccan/likely/likely.h>
  20 #include <ccan/asearch/asearch.h>
  21
  22 /* We keep an ordered array of offsets. */
  23 static bool append(tdb_off_t **arr, size_t *num, tdb_off_t off)
  24 {
  25         tdb_off_t *new = realloc(*arr, (*num + 1) * sizeof(tdb_off_t));
  26         if (!new)
  27                 return false;
  28         new[(*num)++] = off;
  29         *arr = new;
  30         return true;
  31 }
  32
  33 static enum TDB_ERROR check_header(struct tdb_context *tdb, tdb_off_t *recovery,
  34                                    uint64_t *features)
  35 {
  36         uint64_t hash_test;
  37         struct tdb_header hdr;
  38         enum TDB_ERROR ecode;
  39
  40         ecode = tdb_read_convert(tdb, 0, &hdr, sizeof(hdr));
  41         if (ecode != TDB_SUCCESS) {
  42                 return ecode;
  43         }
  44         /* magic food should not be converted, so convert back. */
  45         tdb_convert(tdb, hdr.magic_food, sizeof(hdr.magic_food));
  46
  47         hash_test = TDB_HASH_MAGIC;
  48         hash_test = tdb_hash(tdb, &hash_test, sizeof(hash_test));
  49         if (hdr.hash_test != hash_test) {
  50                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
  51                                   "check: hash test %llu should be %llu",
  52                                   (long long)hdr.hash_test,
  53                                   (long long)hash_test);
  54         }
  55
  56         if (strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0) {
  57                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
  58                                   "check: bad magic '%.*s'",
  59                                   (unsigned)sizeof(hdr.magic_food),
  60                                   hdr.magic_food);
  61         }
  62
  63         /* Features which are used must be a subset of features offered. */
  64         if (hdr.features_used & ~hdr.features_offered) {
  65                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
  66                                   "check: features used (0x%llx) which"
  67                                   " are not offered (0x%llx)",
  68                                   (long long)hdr.features_used,
  69                                   (long long)hdr.features_offered);
  70         }
  71
  72         *features = hdr.features_offered;
  73         *recovery = hdr.recovery;
  74         if (*recovery) {
  75                 if (*recovery < sizeof(hdr)
  76                     || *recovery > tdb->file->map_size) {
  77                         return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
  78                                           "tdb_check:"
  79                                           " invalid recovery offset %zu",
  80                                           (size_t)*recovery);
  81                 }
  82         }
  83
  84         /* Don't check reserved: they *can* be used later. */
  85         return TDB_SUCCESS;
  86 }
  87
  88 static enum TDB_ERROR check_hash_tree(struct tdb_context *tdb,
  89                                       tdb_off_t off, unsigned int group_bits,
  90                                       uint64_t hprefix,
  91                                       unsigned hprefix_bits,
  92                                       tdb_off_t used[],
  93                                       size_t num_used,
  94                                       size_t *num_found,
  95                                       enum TDB_ERROR (*check)(TDB_DATA,
  96                                                               TDB_DATA, void *),
  97                                       void *private_data);
  98
  99 static enum TDB_ERROR check_hash_chain(struct tdb_context *tdb,
 100                                        tdb_off_t off,
 101                                        uint64_t hash,
 102                                        tdb_off_t used[],
 103                                        size_t num_used,
 104                                        size_t *num_found,
 105                                        enum TDB_ERROR (*check)(TDB_DATA,
 106                                                                TDB_DATA,
 107                                                                void *),
 108                                        void *private_data)
 109 {
 110         struct tdb_used_record rec;
 111         enum TDB_ERROR ecode;
 112
 113         ecode = tdb_read_convert(tdb, off, &rec, sizeof(rec));
 114         if (ecode != TDB_SUCCESS) {
 115                 return ecode;
 116         }
 117
 118         if (rec_magic(&rec) != TDB_CHAIN_MAGIC) {
 119                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 120                                   "tdb_check: Bad hash chain magic %llu",
 121                                   (long long)rec_magic(&rec));
 122         }
 123
 124         if (rec_data_length(&rec) != sizeof(struct tdb_chain)) {
 125                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 126                                   "tdb_check:"
 127                                   " Bad hash chain length %llu vs %zu",
 128                                   (long long)rec_data_length(&rec),
 129                                   sizeof(struct tdb_chain));
 130         }
 131         if (rec_key_length(&rec) != 0) {
 132                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 133                                   "tdb_check: Bad hash chain key length %llu",
 134                                   (long long)rec_key_length(&rec));
 135         }
 136         if (rec_hash(&rec) != 0) {
 137                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 138                                   "tdb_check: Bad hash chain hash value %llu",
 139                                   (long long)rec_hash(&rec));
 140         }
 141
 142         off += sizeof(rec);
 143         ecode = check_hash_tree(tdb, off, 0, hash, 64,
 144                                 used, num_used, num_found, check, private_data);
 145         if (ecode != TDB_SUCCESS) {
 146                 return ecode;
 147         }
 148
 149         off = tdb_read_off(tdb, off + offsetof(struct tdb_chain, next));
 150         if (TDB_OFF_IS_ERR(off)) {
 151                 return off;
 152         }
 153         if (off == 0)
 154                 return TDB_SUCCESS;
 155         (*num_found)++;
 156         return check_hash_chain(tdb, off, hash, used, num_used, num_found,
 157                                 check, private_data);
 158 }
 159
 160 static enum TDB_ERROR check_hash_record(struct tdb_context *tdb,
 161                                         tdb_off_t off,
 162                                         uint64_t hprefix,
 163                                         unsigned hprefix_bits,
 164                                         tdb_off_t used[],
 165                                         size_t num_used,
 166                                         size_t *num_found,
 167                                         enum TDB_ERROR (*check)(TDB_DATA,
 168                                                                 TDB_DATA,
 169                                                                 void *),
 170                                         void *private_data)
 171 {
 172         struct tdb_used_record rec;
 173         enum TDB_ERROR ecode;
 174
 175         if (hprefix_bits >= 64)
 176                 return check_hash_chain(tdb, off, hprefix, used, num_used,
 177                                         num_found, check, private_data);
 178
 179         ecode = tdb_read_convert(tdb, off, &rec, sizeof(rec));
 180         if (ecode != TDB_SUCCESS) {
 181                 return ecode;
 182         }
 183
 184         if (rec_magic(&rec) != TDB_HTABLE_MAGIC) {
 185                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 186                                   "tdb_check: Bad hash table magic %llu",
 187                                   (long long)rec_magic(&rec));
 188         }
 189         if (rec_data_length(&rec)
 190             != sizeof(tdb_off_t) << TDB_SUBLEVEL_HASH_BITS) {
 191                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 192                                   "tdb_check:"
 193                                   " Bad hash table length %llu vs %llu",
 194                                   (long long)rec_data_length(&rec),
 195                                   (long long)sizeof(tdb_off_t)
 196                                   << TDB_SUBLEVEL_HASH_BITS);
 197         }
 198         if (rec_key_length(&rec) != 0) {
 199                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 200                                   "tdb_check: Bad hash table key length %llu",
 201                                   (long long)rec_key_length(&rec));
 202         }
 203         if (rec_hash(&rec) != 0) {
 204                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 205                                   "tdb_check: Bad hash table hash value %llu",
 206                                   (long long)rec_hash(&rec));
 207         }
 208
 209         off += sizeof(rec);
 210         return check_hash_tree(tdb, off,
 211                                TDB_SUBLEVEL_HASH_BITS-TDB_HASH_GROUP_BITS,
 212                                hprefix, hprefix_bits,
 213                                used, num_used, num_found, check, private_data);
 214 }
 215
 216 static int off_cmp(const tdb_off_t *a, const tdb_off_t *b)
 217 {
 218         /* Can overflow an int. */
 219         return *a > *b ? 1
 220                 : *a < *b ? -1
 221                 : 0;
 222 }
 223
 224 static uint64_t get_bits(uint64_t h, unsigned num, unsigned *used)
 225 {
 226         *used += num;
 227
 228         return (h >> (64 - *used)) & ((1U << num) - 1);
 229 }
 230
 231 static enum TDB_ERROR check_hash_tree(struct tdb_context *tdb,
 232                                       tdb_off_t off, unsigned int group_bits,
 233                                       uint64_t hprefix,
 234                                       unsigned hprefix_bits,
 235                                       tdb_off_t used[],
 236                                       size_t num_used,
 237                                       size_t *num_found,
 238                                       enum TDB_ERROR (*check)(TDB_DATA,
 239                                                               TDB_DATA, void *),
 240                                       void *private_data)
 241 {
 242         unsigned int g, b;
 243         const tdb_off_t *hash;
 244         struct tdb_used_record rec;
 245         enum TDB_ERROR ecode;
 246
 247         hash = tdb_access_read(tdb, off,
 248                                sizeof(tdb_off_t)
 249                                << (group_bits + TDB_HASH_GROUP_BITS),
 250                                true);
 251         if (TDB_PTR_IS_ERR(hash)) {
 252                 return TDB_PTR_ERR(hash);
 253         }
 254
 255         for (g = 0; g < (1 << group_bits); g++) {
 256                 const tdb_off_t *group = hash + (g << TDB_HASH_GROUP_BITS);
 257                 for (b = 0; b < (1 << TDB_HASH_GROUP_BITS); b++) {
 258                         unsigned int bucket, i, used_bits;
 259                         uint64_t h;
 260                         tdb_off_t *p;
 261                         if (group[b] == 0)
 262                                 continue;
 263
 264                         off = group[b] & TDB_OFF_MASK;
 265                         p = asearch(&off, used, num_used, off_cmp);
 266                         if (!p) {
 267                                 ecode = tdb_logerr(tdb, TDB_ERR_CORRUPT,
 268                                                    TDB_LOG_ERROR,
 269                                                    "tdb_check: Invalid offset"
 270                                                    " %llu in hash",
 271                                                    (long long)off);
 272                                 goto fail;
 273                         }
 274                         /* Mark it invalid. */
 275                         *p ^= 1;
 276                         (*num_found)++;
 277
 278                         if (hprefix_bits == 64) {
 279                                 /* Chained entries are unordered. */
 280                                 if (is_subhash(group[b])) {
 281                                         ecode = TDB_ERR_CORRUPT;
 282                                         tdb_logerr(tdb, ecode,
 283                                                    TDB_LOG_ERROR,
 284                                                    "tdb_check: Invalid chain"
 285                                                    " entry subhash");
 286                                         goto fail;
 287                                 }
 288                                 h = hash_record(tdb, off);
 289                                 if (h != hprefix) {
 290                                         ecode = TDB_ERR_CORRUPT;
 291                                         tdb_logerr(tdb, ecode,
 292                                                    TDB_LOG_ERROR,
 293                                                    "check: bad hash chain"
 294                                                    " placement"
 295                                                    " 0x%llx vs 0x%llx",
 296                                                    (long long)h,
 297                                                    (long long)hprefix);
 298                                         goto fail;
 299                                 }
 300                                 ecode = tdb_read_convert(tdb, off, &rec,
 301                                                          sizeof(rec));
 302                                 if (ecode != TDB_SUCCESS) {
 303                                         goto fail;
 304                                 }
 305                                 goto check;
 306                         }
 307
 308                         if (is_subhash(group[b])) {
 309                                 uint64_t subprefix;
 310                                 subprefix = (hprefix
 311                                      << (group_bits + TDB_HASH_GROUP_BITS))
 312                                         + g * (1 << TDB_HASH_GROUP_BITS) + b;
 313
 314                                 ecode = check_hash_record(tdb,
 315                                                group[b] & TDB_OFF_MASK,
 316                                                subprefix,
 317                                                hprefix_bits
 318                                                        + group_bits
 319                                                        + TDB_HASH_GROUP_BITS,
 320                                                used, num_used, num_found,
 321                                                check, private_data);
 322                                 if (ecode != TDB_SUCCESS) {
 323                                         goto fail;
 324                                 }
 325                                 continue;
 326                         }
 327                         /* A normal entry */
 328
 329                         /* Does it belong here at all? */
 330                         h = hash_record(tdb, off);
 331                         used_bits = 0;
 332                         if (get_bits(h, hprefix_bits, &used_bits) != hprefix
 333                             && hprefix_bits) {
 334                                 ecode = tdb_logerr(tdb, TDB_ERR_CORRUPT,
 335                                                    TDB_LOG_ERROR,
 336                                                    "check: bad hash placement"
 337                                                    " 0x%llx vs 0x%llx",
 338                                                    (long long)h,
 339                                                    (long long)hprefix);
 340                                 goto fail;
 341                         }
 342
 343                         /* Does it belong in this group? */
 344                         if (get_bits(h, group_bits, &used_bits) != g) {
 345                                 ecode = tdb_logerr(tdb, TDB_ERR_CORRUPT,
 346                                                    TDB_LOG_ERROR,
 347                                                    "check: bad group %llu"
 348                                                    " vs %u",
 349                                                    (long long)h, g);
 350                                 goto fail;
 351                         }
 352
 353                         /* Are bucket bits correct? */
 354                         bucket = group[b] & TDB_OFF_HASH_GROUP_MASK;
 355                         if (get_bits(h, TDB_HASH_GROUP_BITS, &used_bits)
 356                             != bucket) {
 357                                 used_bits -= TDB_HASH_GROUP_BITS;
 358                                 ecode = tdb_logerr(tdb, TDB_ERR_CORRUPT,
 359                                                    TDB_LOG_ERROR,
 360                                                    "check: bad bucket %u vs %u",
 361                                                    (unsigned)get_bits(h,
 362                                                         TDB_HASH_GROUP_BITS,
 363                                                         &used_bits),
 364                                                    bucket);
 365                                 goto fail;
 366                         }
 367
 368                         /* There must not be any zero entries between
 369                          * the bucket it belongs in and this one! */
 370                         for (i = bucket;
 371                              i != b;
 372                              i = (i + 1) % (1 << TDB_HASH_GROUP_BITS)) {
 373                                 if (group[i] == 0) {
 374                                         ecode = TDB_ERR_CORRUPT;
 375                                         tdb_logerr(tdb, ecode,
 376                                                    TDB_LOG_ERROR,
 377                                                    "check: bad group placement"
 378                                                    " %u vs %u",
 379                                                    b, bucket);
 380                                         goto fail;
 381                                 }
 382                         }
 383
 384                         ecode = tdb_read_convert(tdb, off, &rec, sizeof(rec));
 385                         if (ecode != TDB_SUCCESS) {
 386                                 goto fail;
 387                         }
 388
 389                         /* Bottom bits must match header. */
 390                         if ((h & ((1 << 11)-1)) != rec_hash(&rec)) {
 391                                 ecode = tdb_logerr(tdb, TDB_ERR_CORRUPT,
 392                                                    TDB_LOG_ERROR,
 393                                                    "tdb_check: Bad hash magic"
 394                                                    " at offset %llu"
 395                                                    " (0x%llx vs 0x%llx)",
 396                                                    (long long)off,
 397                                                    (long long)h,
 398                                                    (long long)rec_hash(&rec));
 399                                 goto fail;
 400                         }
 401
 402                 check:
 403                         if (check) {
 404                                 TDB_DATA key, data;
 405                                 key.dsize = rec_key_length(&rec);
 406                                 data.dsize = rec_data_length(&rec);
 407                                 key.dptr = (void *)tdb_access_read(tdb,
 408                                                    off + sizeof(rec),
 409                                                    key.dsize + data.dsize,
 410                                                    false);
 411                                 if (TDB_PTR_IS_ERR(key.dptr)) {
 412                                         ecode = TDB_PTR_ERR(key.dptr);
 413                                         goto fail;
 414                                 }
 415                                 data.dptr = key.dptr + key.dsize;
 416                                 ecode = check(key, data, private_data);
 417                                 if (ecode != TDB_SUCCESS) {
 418                                         goto fail;
 419                                 }
 420                                 tdb_access_release(tdb, key.dptr);
 421                         }
 422                 }
 423         }
 424         tdb_access_release(tdb, hash);
 425         return TDB_SUCCESS;
 426
 427 fail:
 428         tdb_access_release(tdb, hash);
 429         return ecode;
 430 }
 431
 432 static enum TDB_ERROR check_hash(struct tdb_context *tdb,
 433                                  tdb_off_t used[],
 434                                  size_t num_used, size_t num_ftables,
 435                                  int (*check)(TDB_DATA, TDB_DATA, void *),
 436                                  void *private_data)
 437 {
 438         /* Free tables also show up as used. */
 439         size_t num_found = num_ftables;
 440         enum TDB_ERROR ecode;
 441
 442         ecode = check_hash_tree(tdb, offsetof(struct tdb_header, hashtable),
 443                                 TDB_TOPLEVEL_HASH_BITS-TDB_HASH_GROUP_BITS,
 444                                 0, 0, used, num_used, &num_found,
 445                                 check, private_data);
 446         if (ecode == TDB_SUCCESS) {
 447                 if (num_found != num_used) {
 448                         ecode = tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 449                                            "tdb_check: Not all entries"
 450                                            " are in hash");
 451                 }
 452         }
 453         return ecode;
 454 }
 455
 456 static enum TDB_ERROR check_free(struct tdb_context *tdb,
 457                                  tdb_off_t off,
 458                                  const struct tdb_free_record *frec,
 459                                  tdb_off_t prev, unsigned int ftable,
 460                                  unsigned int bucket)
 461 {
 462         enum TDB_ERROR ecode;
 463
 464         if (frec_magic(frec) != TDB_FREE_MAGIC) {
 465                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 466                                   "tdb_check: offset %llu bad magic 0x%llx",
 467                                   (long long)off,
 468                                   (long long)frec->magic_and_prev);
 469         }
 470         if (frec_ftable(frec) != ftable) {
 471                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 472                                   "tdb_check: offset %llu bad freetable %u",
 473                                   (long long)off, frec_ftable(frec));
 474
 475         }
 476
 477         ecode = tdb->methods->oob(tdb, off
 478                                   + frec_len(frec)
 479                                   + sizeof(struct tdb_used_record),
 480                                   false);
 481         if (ecode != TDB_SUCCESS) {
 482                 return ecode;
 483         }
 484         if (size_to_bucket(frec_len(frec)) != bucket) {
 485                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 486                                   "tdb_check: offset %llu in wrong bucket"
 487                                   " (%u vs %u)",
 488                                   (long long)off,
 489                                   bucket, size_to_bucket(frec_len(frec)));
 490         }
 491         if (prev != frec_prev(frec)) {
 492                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 493                                   "tdb_check: offset %llu bad prev"
 494                                   " (%llu vs %llu)",
 495                                   (long long)off,
 496                                   (long long)prev, (long long)frec_len(frec));
 497         }
 498         return TDB_SUCCESS;
 499 }
 500
 501 static enum TDB_ERROR check_free_table(struct tdb_context *tdb,
 502                                        tdb_off_t ftable_off,
 503                                        unsigned ftable_num,
 504                                        tdb_off_t fr[],
 505                                        size_t num_free,
 506                                        size_t *num_found)
 507 {
 508         struct tdb_freetable ft;
 509         tdb_off_t h;
 510         unsigned int i;
 511         enum TDB_ERROR ecode;
 512
 513         ecode = tdb_read_convert(tdb, ftable_off, &ft, sizeof(ft));
 514         if (ecode != TDB_SUCCESS) {
 515                 return ecode;
 516         }
 517
 518         if (rec_magic(&ft.hdr) != TDB_FTABLE_MAGIC
 519             || rec_key_length(&ft.hdr) != 0
 520             || rec_data_length(&ft.hdr) != sizeof(ft) - sizeof(ft.hdr)
 521             || rec_hash(&ft.hdr) != 0) {
 522                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 523                                   "tdb_check: Invalid header on free table");
 524         }
 525
 526         for (i = 0; i < TDB_FREE_BUCKETS; i++) {
 527                 tdb_off_t off, prev = 0, *p;
 528                 struct tdb_free_record f;
 529
 530                 h = bucket_off(ftable_off, i);
 531                 for (off = tdb_read_off(tdb, h); off; off = f.next) {
 532                         if (TDB_OFF_IS_ERR(off)) {
 533                                 return off;
 534                         }
 535                         ecode = tdb_read_convert(tdb, off, &f, sizeof(f));
 536                         if (ecode != TDB_SUCCESS) {
 537                                 return ecode;
 538                         }
 539                         ecode = check_free(tdb, off, &f, prev, ftable_num, i);
 540                         if (ecode != TDB_SUCCESS) {
 541                                 return ecode;
 542                         }
 543
 544                         /* FIXME: Check hash bits */
 545                         p = asearch(&off, fr, num_free, off_cmp);
 546                         if (!p) {
 547                                 return tdb_logerr(tdb, TDB_ERR_CORRUPT,
 548                                                   TDB_LOG_ERROR,
 549                                                   "tdb_check: Invalid offset"
 550                                                   " %llu in free table",
 551                                                   (long long)off);
 552                         }
 553                         /* Mark it invalid. */
 554                         *p ^= 1;
 555                         (*num_found)++;
 556                         prev = off;
 557                 }
 558         }
 559         return TDB_SUCCESS;
 560 }
 561
 562 /* Slow, but should be very rare. */
 563 tdb_off_t dead_space(struct tdb_context *tdb, tdb_off_t off)
 564 {
 565         size_t len;
 566         enum TDB_ERROR ecode;
 567
 568         for (len = 0; off + len < tdb->file->map_size; len++) {
 569                 char c;
 570                 ecode = tdb->methods->tread(tdb, off, &c, 1);
 571                 if (ecode != TDB_SUCCESS) {
 572                         return ecode;
 573                 }
 574                 if (c != 0 && c != 0x43)
 575                         break;
 576         }
 577         return len;
 578 }
 579
 580 static enum TDB_ERROR check_linear(struct tdb_context *tdb,
 581                                    tdb_off_t **used, size_t *num_used,
 582                                    tdb_off_t **fr, size_t *num_free,
 583                                    uint64_t features, tdb_off_t recovery)
 584 {
 585         tdb_off_t off;
 586         tdb_len_t len;
 587         enum TDB_ERROR ecode;
 588         bool found_recovery = false;
 589
 590         for (off = sizeof(struct tdb_header);
 591              off < tdb->file->map_size;
 592              off += len) {
 593                 union {
 594                         struct tdb_used_record u;
 595                         struct tdb_free_record f;
 596                         struct tdb_recovery_record r;
 597                 } rec;
 598                 /* r is larger: only get that if we need to. */
 599                 ecode = tdb_read_convert(tdb, off, &rec, sizeof(rec.f));
 600                 if (ecode != TDB_SUCCESS) {
 601                         return ecode;
 602                 }
 603
 604                 /* If we crash after ftruncate, we can get zeroes or fill. */
 605                 if (rec.r.magic == TDB_RECOVERY_INVALID_MAGIC
 606                     || rec.r.magic ==  0x4343434343434343ULL) {
 607                         ecode = tdb_read_convert(tdb, off, &rec, sizeof(rec.r));
 608                         if (ecode != TDB_SUCCESS) {
 609                                 return ecode;
 610                         }
 611                         if (recovery == off) {
 612                                 found_recovery = true;
 613                                 len = sizeof(rec.r) + rec.r.max_len;
 614                         } else {
 615                                 len = dead_space(tdb, off);
 616                                 if (TDB_OFF_IS_ERR(len)) {
 617                                         return len;
 618                                 }
 619                                 if (len < sizeof(rec.r)) {
 620                                         return tdb_logerr(tdb, TDB_ERR_CORRUPT,
 621                                                           TDB_LOG_ERROR,
 622                                                           "tdb_check: invalid"
 623                                                           " dead space at %zu",
 624                                                           (size_t)off);
 625                                 }
 626
 627                                 tdb_logerr(tdb, TDB_SUCCESS, TDB_LOG_WARNING,
 628                                            "Dead space at %zu-%zu (of %zu)",
 629                                            (size_t)off, (size_t)(off + len),
 630                                            (size_t)tdb->file->map_size);
 631                         }
 632                 } else if (rec.r.magic == TDB_RECOVERY_MAGIC) {
 633                         ecode = tdb_read_convert(tdb, off, &rec, sizeof(rec.r));
 634                         if (ecode != TDB_SUCCESS) {
 635                                 return ecode;
 636                         }
 637                         if (recovery != off) {
 638                                 return tdb_logerr(tdb, TDB_ERR_CORRUPT,
 639                                                   TDB_LOG_ERROR,
 640                                                   "tdb_check: unexpected"
 641                                                   " recovery record at offset"
 642                                                   " %zu",
 643                                                   (size_t)off);
 644                         }
 645                         if (rec.r.len > rec.r.max_len) {
 646                                 return tdb_logerr(tdb, TDB_ERR_CORRUPT,
 647                                                   TDB_LOG_ERROR,
 648                                                   "tdb_check: invalid recovery"
 649                                                   " length %zu",
 650                                                   (size_t)rec.r.len);
 651                         }
 652                         if (rec.r.eof > tdb->file->map_size) {
 653                                 return tdb_logerr(tdb, TDB_ERR_CORRUPT,
 654                                                   TDB_LOG_ERROR,
 655                                                   "tdb_check: invalid old EOF"
 656                                                   " %zu", (size_t)rec.r.eof);
 657                         }
 658                         found_recovery = true;
 659                         len = sizeof(rec.r) + rec.r.max_len;
 660                 } else if (frec_magic(&rec.f) == TDB_FREE_MAGIC) {
 661                         len = sizeof(rec.u) + frec_len(&rec.f);
 662                         if (off + len > tdb->file->map_size) {
 663                                 return tdb_logerr(tdb, TDB_ERR_CORRUPT,
 664                                                   TDB_LOG_ERROR,
 665                                                   "tdb_check: free overlength"
 666                                                   " %llu at offset %llu",
 667                                                   (long long)len,
 668                                                   (long long)off);
 669                         }
 670                         /* This record should be in free lists. */
 671                         if (frec_ftable(&rec.f) != TDB_FTABLE_NONE
 672                             && !append(fr, num_free, off)) {
 673                                 return tdb_logerr(tdb, TDB_ERR_OOM,
 674                                                   TDB_LOG_ERROR,
 675                                                   "tdb_check: tracking %zu'th"
 676                                                   " free record.", *num_free);
 677                         }
 678                 } else if (rec_magic(&rec.u) == TDB_USED_MAGIC
 679                            || rec_magic(&rec.u) == TDB_CHAIN_MAGIC
 680                            || rec_magic(&rec.u) == TDB_HTABLE_MAGIC
 681                            || rec_magic(&rec.u) == TDB_FTABLE_MAGIC) {
 682                         uint64_t klen, dlen, extra;
 683
 684                         /* This record is used! */
 685                         if (!append(used, num_used, off)) {
 686                                 return tdb_logerr(tdb, TDB_ERR_OOM,
 687                                                   TDB_LOG_ERROR,
 688                                                   "tdb_check: tracking %zu'th"
 689                                                   " used record.", *num_used);
 690                         }
 691
 692                         klen = rec_key_length(&rec.u);
 693                         dlen = rec_data_length(&rec.u);
 694                         extra = rec_extra_padding(&rec.u);
 695
 696                         len = sizeof(rec.u) + klen + dlen + extra;
 697                         if (off + len > tdb->file->map_size) {
 698                                 return tdb_logerr(tdb, TDB_ERR_CORRUPT,
 699                                                   TDB_LOG_ERROR,
 700                                                   "tdb_check: used overlength"
 701                                                   " %llu at offset %llu",
 702                                                   (long long)len,
 703                                                   (long long)off);
 704                         }
 705
 706                         if (len < sizeof(rec.f)) {
 707                                 return tdb_logerr(tdb, TDB_ERR_CORRUPT,
 708                                                   TDB_LOG_ERROR,
 709                                                   "tdb_check: too short record"
 710                                                   " %llu at %llu",
 711                                                   (long long)len,
 712                                                   (long long)off);
 713                         }
 714
 715                         /* Check that records have correct 0 at end (but may
 716                          * not in future). */
 717                         if (extra && !features) {
 718                                 const char *p;
 719                                 char c;
 720                                 p = tdb_access_read(tdb, off + sizeof(rec.u)
 721                                                     + klen + dlen, 1, false);
 722                                 if (TDB_PTR_IS_ERR(p))
 723                                         return TDB_PTR_ERR(p);
 724                                 c = *p;
 725                                 tdb_access_release(tdb, p);
 726
 727                                 if (c != '\0') {
 728                                         return tdb_logerr(tdb, TDB_ERR_CORRUPT,
 729                                                           TDB_LOG_ERROR,
 730                                                           "tdb_check:"
 731                                                           " non-zero extra"
 732                                                           " at %llu",
 733                                                           (long long)off);
 734                                 }
 735                         }
 736                 } else {
 737                         return tdb_logerr(tdb, TDB_ERR_CORRUPT,
 738                                           TDB_LOG_ERROR,
 739                                           "tdb_check: Bad magic 0x%llx"
 740                                           " at offset %zu",
 741                                           (long long)rec_magic(&rec.u),
 742                                           (size_t)off);
 743                 }
 744         }
 745
 746         /* We must have found recovery area if there was one. */
 747         if (recovery != 0 && !found_recovery) {
 748                 return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 749                                   "tdb_check: expected a recovery area at %zu",
 750                                   (size_t)recovery);
 751         }
 752
 753         return TDB_SUCCESS;
 754 }
 755
 756 enum TDB_ERROR tdb_check_(struct tdb_context *tdb,
 757                           enum TDB_ERROR (*check)(TDB_DATA key, TDB_DATA data,
 758                                                   void *private),
 759                           void *private)
 760 {
 761         tdb_off_t *fr = NULL, *used = NULL, ft, recovery;
 762         size_t num_free = 0, num_used = 0, num_found = 0, num_ftables = 0;
 763         uint64_t features;
 764         enum TDB_ERROR ecode;
 765
 766         ecode = tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, false);
 767         if (ecode != TDB_SUCCESS) {
 768                 return ecode;
 769         }
 770
 771         ecode = tdb_lock_expand(tdb, F_RDLCK);
 772         if (ecode != TDB_SUCCESS) {
 773                 tdb_allrecord_unlock(tdb, F_RDLCK);
 774                 return ecode;
 775         }
 776
 777         ecode = check_header(tdb, &recovery, &features);
 778         if (ecode != TDB_SUCCESS)
 779                 goto out;
 780
 781         /* First we do a linear scan, checking all records. */
 782         ecode = check_linear(tdb, &used, &num_used, &fr, &num_free, features,
 783                              recovery);
 784         if (ecode != TDB_SUCCESS)
 785                 goto out;
 786
 787         for (ft = first_ftable(tdb); ft; ft = next_ftable(tdb, ft)) {
 788                 if (TDB_OFF_IS_ERR(ft)) {
 789                         ecode = ft;
 790                         goto out;
 791                 }
 792                 ecode = check_free_table(tdb, ft, num_ftables, fr, num_free,
 793                                          &num_found);
 794                 if (ecode != TDB_SUCCESS)
 795                         goto out;
 796                 num_ftables++;
 797         }
 798
 799         /* FIXME: Check key uniqueness? */
 800         ecode = check_hash(tdb, used, num_used, num_ftables, check, private);
 801         if (ecode != TDB_SUCCESS)
 802                 goto out;
 803
 804         if (num_found != num_free) {
 805                 ecode = tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 806                                    "tdb_check: Not all entries are in"
 807                                    " free table");
 808         }
 809
 810 out:
 811         tdb_allrecord_unlock(tdb, F_RDLCK);
 812         tdb_unlock_expand(tdb, F_RDLCK);
 813         free(fr);
 814         free(used);
 815         return ecode;
 816 }