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 bool check_header(struct tdb_context *tdb, tdb_off_t *recovery)
  34 {
  35         uint64_t hash_test;
  36         struct tdb_header hdr;
  37
  38         if (tdb_read_convert(tdb, 0, &hdr, sizeof(hdr)) == -1)
  39                 return false;
  40         /* magic food should not be converted, so convert back. */
  41         tdb_convert(tdb, hdr.magic_food, sizeof(hdr.magic_food));
  42
  43         hash_test = TDB_HASH_MAGIC;
  44         hash_test = tdb_hash(tdb, &hash_test, sizeof(hash_test));
  45         if (hdr.hash_test != hash_test) {
  46                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
  47                          "check: hash test %llu should be %llu\n",
  48                          (long long)hdr.hash_test,
  49                          (long long)hash_test);
  50                 return false;
  51         }
  52
  53         if (strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0) {
  54                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
  55                          "check: bad magic '%.*s'\n",
  56                          (unsigned)sizeof(hdr.magic_food), hdr.magic_food);
  57                 return false;
  58         }
  59
  60         *recovery = hdr.recovery;
  61         if (*recovery) {
  62                 if (*recovery < sizeof(hdr) || *recovery > tdb->map_size) {
  63                         tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
  64                                  "tdb_check: invalid recovery offset %zu\n",
  65                                  (size_t)*recovery);
  66                         return false;
  67                 }
  68         }
  69
  70         /* Don't check reserved: they *can* be used later. */
  71         return true;
  72 }
  73
  74 static bool check_hash_tree(struct tdb_context *tdb,
  75                             tdb_off_t off, unsigned int group_bits,
  76                             uint64_t hprefix,
  77                             unsigned hprefix_bits,
  78                             tdb_off_t used[],
  79                             size_t num_used,
  80                             size_t *num_found,
  81                             int (*check)(TDB_DATA, TDB_DATA, void *),
  82                             void *private_data);
  83
  84 static bool check_hash_record(struct tdb_context *tdb,
  85                               tdb_off_t off,
  86                               uint64_t hprefix,
  87                               unsigned hprefix_bits,
  88                               tdb_off_t used[],
  89                               size_t num_used,
  90                               size_t *num_found,
  91                               int (*check)(TDB_DATA, TDB_DATA, void *),
  92                               void *private_data)
  93 {
  94         struct tdb_used_record rec;
  95
  96         if (tdb_read_convert(tdb, off, &rec, sizeof(rec)) == -1)
  97                 return false;
  98
  99         if (rec_data_length(&rec)
 100             != sizeof(tdb_off_t) << TDB_SUBLEVEL_HASH_BITS) {
 101                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 102                          "tdb_check: Bad hash table length %llu vs %llu\n",
 103                          (long long)rec_data_length(&rec),
 104                          (long long)sizeof(tdb_off_t)<<TDB_SUBLEVEL_HASH_BITS);
 105                 return false;
 106         }
 107         if (rec_key_length(&rec) != 0) {
 108                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 109                          "tdb_check: Bad hash table key length %llu\n",
 110                          (long long)rec_key_length(&rec));
 111                 return false;
 112         }
 113         if (rec_hash(&rec) != 0) {
 114                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 115                          "tdb_check: Bad hash table hash value %llu\n",
 116                          (long long)rec_hash(&rec));
 117                 return false;
 118         }
 119
 120         off += sizeof(rec);
 121         return check_hash_tree(tdb, off,
 122                                TDB_SUBLEVEL_HASH_BITS-TDB_HASH_GROUP_BITS,
 123                                hprefix, hprefix_bits,
 124                                used, num_used, num_found, check, private_data);
 125 }
 126
 127 static int off_cmp(const tdb_off_t *a, const tdb_off_t *b)
 128 {
 129         /* Can overflow an int. */
 130         return *a > *b ? 1
 131                 : *a < *b ? -1
 132                 : 0;
 133 }
 134
 135 static uint64_t get_bits(uint64_t h, unsigned num, unsigned *used)
 136 {
 137         *used += num;
 138
 139         return (h >> (64 - *used)) & ((1U << num) - 1);
 140 }
 141
 142 static bool check_hash_tree(struct tdb_context *tdb,
 143                             tdb_off_t off, unsigned int group_bits,
 144                             uint64_t hprefix,
 145                             unsigned hprefix_bits,
 146                             tdb_off_t used[],
 147                             size_t num_used,
 148                             size_t *num_found,
 149                             int (*check)(TDB_DATA, TDB_DATA, void *),
 150                             void *private_data)
 151 {
 152         unsigned int g, b;
 153         const tdb_off_t *hash;
 154         struct tdb_used_record rec;
 155
 156         hash = tdb_access_read(tdb, off,
 157                                sizeof(tdb_off_t)
 158                                << (group_bits + TDB_HASH_GROUP_BITS),
 159                                true);
 160         if (!hash)
 161                 return false;
 162
 163         for (g = 0; g < (1 << group_bits); g++) {
 164                 const tdb_off_t *group = hash + (g << TDB_HASH_GROUP_BITS);
 165                 for (b = 0; b < (1 << TDB_HASH_GROUP_BITS); b++) {
 166                         unsigned int bucket, i, used_bits;
 167                         uint64_t h;
 168                         tdb_off_t *p;
 169                         if (group[b] == 0)
 170                                 continue;
 171
 172                         off = group[b] & TDB_OFF_MASK;
 173                         p = asearch(&off, used, num_used, off_cmp);
 174                         if (!p) {
 175                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 176                                          "tdb_check: Invalid offset %llu "
 177                                          "in hash\n",
 178                                          (long long)off);
 179                                 goto fail;
 180                         }
 181                         /* Mark it invalid. */
 182                         *p ^= 1;
 183                         (*num_found)++;
 184
 185                         if (is_subhash(group[b])) {
 186                                 uint64_t subprefix;
 187                                 subprefix = (hprefix
 188                                      << (group_bits + TDB_HASH_GROUP_BITS))
 189                                         + g * (1 << TDB_HASH_GROUP_BITS) + b;
 190
 191                                 if (!check_hash_record(tdb,
 192                                                group[b] & TDB_OFF_MASK,
 193                                                subprefix,
 194                                                hprefix_bits
 195                                                        + group_bits
 196                                                        + TDB_HASH_GROUP_BITS,
 197                                                used, num_used, num_found,
 198                                                check, private_data))
 199                                         goto fail;
 200                                 continue;
 201                         }
 202                         /* A normal entry */
 203
 204                         /* Does it belong here at all? */
 205                         h = hash_record(tdb, off);
 206                         used_bits = 0;
 207                         if (get_bits(h, hprefix_bits, &used_bits) != hprefix
 208                             && hprefix_bits) {
 209                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 210                                          "check: bad hash placement"
 211                                          " 0x%llx vs 0x%llx\n",
 212                                          (long long)h, (long long)hprefix);
 213                                 goto fail;
 214                         }
 215
 216                         /* Does it belong in this group? */
 217                         if (get_bits(h, group_bits, &used_bits) != g) {
 218                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 219                                          "check: bad group %llu vs %u\n",
 220                                          (long long)h, g);
 221                                 goto fail;
 222                         }
 223
 224                         /* Are bucket bits correct? */
 225                         bucket = group[b] & TDB_OFF_HASH_GROUP_MASK;
 226                         if (get_bits(h, TDB_HASH_GROUP_BITS, &used_bits)
 227                             != bucket) {
 228                                 used_bits -= TDB_HASH_GROUP_BITS;
 229                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 230                                          "check: bad bucket %u vs %u\n",
 231                                          (unsigned)get_bits(h,
 232                                                             TDB_HASH_GROUP_BITS,
 233                                                             &used_bits),
 234                                          bucket);
 235                                 goto fail;
 236                         }
 237
 238                         /* There must not be any zero entries between
 239                          * the bucket it belongs in and this one! */
 240                         for (i = bucket;
 241                              i != b;
 242                              i = (i + 1) % (1 << TDB_HASH_GROUP_BITS)) {
 243                                 if (group[i] == 0) {
 244                                         tdb->log(tdb, TDB_DEBUG_ERROR,
 245                                                  tdb->log_priv,
 246                                                  "check: bad group placement"
 247                                                  " %u vs %u\n",
 248                                                  b, bucket);
 249                                         goto fail;
 250                                 }
 251                         }
 252
 253                         if (tdb_read_convert(tdb, off, &rec, sizeof(rec)) == -1)
 254                                 goto fail;
 255
 256                         /* Bottom bits must match header. */
 257                         if ((h & ((1 << 11)-1)) != rec_hash(&rec)) {
 258                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 259                                          "tdb_check: Bad hash magic at"
 260                                          " offset %llu (0x%llx vs 0x%llx)\n",
 261                                          (long long)off,
 262                                          (long long)h,
 263                                          (long long)rec_hash(&rec));
 264                                 goto fail;
 265                         }
 266
 267                         if (check) {
 268                                 TDB_DATA key, data;
 269                                 key.dsize = rec_key_length(&rec);
 270                                 data.dsize = rec_data_length(&rec);
 271                                 key.dptr = (void *)tdb_access_read(tdb,
 272                                                    off + sizeof(rec),
 273                                                    key.dsize + data.dsize,
 274                                                    false);
 275                                 if (!key.dptr)
 276                                         goto fail;
 277                                 data.dptr = key.dptr + key.dsize;
 278                                 if (check(key, data, private_data) != 0)
 279                                         goto fail;
 280                                 tdb_access_release(tdb, key.dptr);
 281                         }
 282                 }
 283         }
 284         tdb_access_release(tdb, hash);
 285         return true;
 286
 287 fail:
 288         tdb_access_release(tdb, hash);
 289         return false;
 290 }
 291
 292 static bool check_hash(struct tdb_context *tdb,
 293                        tdb_off_t used[],
 294                        size_t num_used, size_t num_flists,
 295                        int (*check)(TDB_DATA, TDB_DATA, void *),
 296                        void *private_data)
 297 {
 298         /* Free lists also show up as used. */
 299         size_t num_found = num_flists;
 300
 301         if (!check_hash_tree(tdb, offsetof(struct tdb_header, hashtable),
 302                              TDB_TOPLEVEL_HASH_BITS-TDB_HASH_GROUP_BITS,
 303                              0, 0, used, num_used, &num_found,
 304                              check, private_data))
 305                 return false;
 306
 307         if (num_found != num_used) {
 308                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 309                          "tdb_check: Not all entries are in hash\n");
 310                 return false;
 311         }
 312         return true;
 313 }
 314
 315 static bool check_free(struct tdb_context *tdb,
 316                        tdb_off_t off,
 317                        const struct tdb_free_record *frec,
 318                        tdb_off_t prev, tdb_off_t flist_off, unsigned int bucket)
 319 {
 320         if (frec_magic(frec) != TDB_FREE_MAGIC) {
 321                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 322                          "tdb_check: offset %llu bad magic 0x%llx\n",
 323                          (long long)off, (long long)frec->magic_and_meta);
 324                 return false;
 325         }
 326         if (frec_flist(frec) != flist_off) {
 327                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 328                          "tdb_check: offset %llu bad freelist 0x%llx\n",
 329                          (long long)off, (long long)frec_flist(frec));
 330                 return false;
 331         }
 332
 333         if (tdb->methods->oob(tdb, off
 334                               + frec->data_len+sizeof(struct tdb_used_record),
 335                               false))
 336                 return false;
 337         if (size_to_bucket(frec->data_len) != bucket) {
 338                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 339                          "tdb_check: offset %llu in wrong bucket %u vs %u\n",
 340                          (long long)off,
 341                          bucket, size_to_bucket(frec->data_len));
 342                 return false;
 343         }
 344         if (prev != frec->prev) {
 345                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 346                          "tdb_check: offset %llu bad prev %llu vs %llu\n",
 347                          (long long)off,
 348                          (long long)prev, (long long)frec->prev);
 349                 return false;
 350         }
 351         return true;
 352 }
 353
 354 static bool check_free_list(struct tdb_context *tdb,
 355                             tdb_off_t flist_off,
 356                             tdb_off_t free[],
 357                             size_t num_free,
 358                             size_t *num_found)
 359 {
 360         struct tdb_freelist flist;
 361         tdb_off_t h;
 362         unsigned int i;
 363
 364         if (tdb_read_convert(tdb, flist_off, &flist, sizeof(flist)) == -1)
 365                 return false;
 366
 367         if (rec_magic(&flist.hdr) != TDB_MAGIC
 368             || rec_key_length(&flist.hdr) != 0
 369             || rec_data_length(&flist.hdr) != sizeof(flist) - sizeof(flist.hdr)
 370             || rec_hash(&flist.hdr) != 1) {
 371                 tdb->log(tdb, TDB_DEBUG_ERROR,
 372                          tdb->log_priv,
 373                          "tdb_check: Invalid header on free list\n");
 374                 return false;
 375         }
 376
 377         for (i = 0; i < TDB_FREE_BUCKETS; i++) {
 378                 tdb_off_t off, prev = 0, *p;
 379                 struct tdb_free_record f;
 380
 381                 h = bucket_off(flist_off, i);
 382                 for (off = tdb_read_off(tdb, h); off; off = f.next) {
 383                         if (off == TDB_OFF_ERR)
 384                                 return false;
 385                         if (tdb_read_convert(tdb, off, &f, sizeof(f)))
 386                                 return false;
 387                         if (!check_free(tdb, off, &f, prev, flist_off, i))
 388                                 return false;
 389
 390                         /* FIXME: Check hash bits */
 391                         p = asearch(&off, free, num_free, off_cmp);
 392                         if (!p) {
 393                                 tdb->log(tdb, TDB_DEBUG_ERROR,
 394                                          tdb->log_priv,
 395                                          "tdb_check: Invalid offset"
 396                                          " %llu in free table\n",
 397                                          (long long)off);
 398                                 return false;
 399                         }
 400                         /* Mark it invalid. */
 401                         *p ^= 1;
 402                         (*num_found)++;
 403                         prev = off;
 404                 }
 405         }
 406         return true;
 407 }
 408
 409 /* Slow, but should be very rare. */
 410 size_t dead_space(struct tdb_context *tdb, tdb_off_t off)
 411 {
 412         size_t len;
 413
 414         for (len = 0; off + len < tdb->map_size; len++) {
 415                 char c;
 416                 if (tdb->methods->read(tdb, off, &c, 1))
 417                         return 0;
 418                 if (c != 0 && c != 0x43)
 419                         break;
 420         }
 421         return len;
 422 }
 423
 424 static bool check_linear(struct tdb_context *tdb,
 425                          tdb_off_t **used, size_t *num_used,
 426                          tdb_off_t **free, size_t *num_free,
 427                          tdb_off_t recovery)
 428 {
 429         tdb_off_t off;
 430         tdb_len_t len;
 431         bool found_recovery = false;
 432
 433         for (off = sizeof(struct tdb_header); off < tdb->map_size; off += len) {
 434                 union {
 435                         struct tdb_used_record u;
 436                         struct tdb_free_record f;
 437                         struct tdb_recovery_record r;
 438                 } pad, *p;
 439                 p = tdb_get(tdb, off, &pad, sizeof(pad));
 440                 if (!p)
 441                         return false;
 442
 443                 /* If we crash after ftruncate, we can get zeroes or fill. */
 444                 if (p->r.magic == TDB_RECOVERY_INVALID_MAGIC
 445                     || p->r.magic ==  0x4343434343434343ULL) {
 446                         if (recovery == off) {
 447                                 found_recovery = true;
 448                                 len = sizeof(p->r) + p->r.max_len;
 449                         } else {
 450                                 len = dead_space(tdb, off);
 451                                 if (len < sizeof(p->r)) {
 452                                         tdb->log(tdb, TDB_DEBUG_ERROR,
 453                                                  tdb->log_priv,
 454                                                  "tdb_check: invalid dead space"
 455                                                  " at %zu\n", (size_t)off);
 456                                         return false;
 457                                 }
 458
 459                                 tdb->log(tdb, TDB_DEBUG_WARNING, tdb->log_priv,
 460                                          "Dead space at %zu-%zu (of %zu)\n",
 461                                          (size_t)off, (size_t)(off + len),
 462                                          (size_t)tdb->map_size);
 463                         }
 464                 } else if (p->r.magic == TDB_RECOVERY_MAGIC) {
 465                         if (recovery != off) {
 466                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 467                                          "tdb_check: unexpected recovery"
 468                                          " record at offset %zu\n",
 469                                          (size_t)off);
 470                                 return false;
 471                         }
 472                         found_recovery = true;
 473                         len = sizeof(p->r) + p->r.max_len;
 474                 } else if (frec_magic(&p->f) == TDB_FREE_MAGIC
 475                            || frec_magic(&p->f) == TDB_COALESCING_MAGIC) {
 476                         len = sizeof(p->u) + p->f.data_len;
 477                         if (off + len > tdb->map_size) {
 478                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 479                                          "tdb_check: free overlength %llu"
 480                                          " at offset %llu\n",
 481                                          (long long)len, (long long)off);
 482                                 return false;
 483                         }
 484                         /* This record is free! */
 485                         if (frec_magic(&p->f) == TDB_FREE_MAGIC
 486                             && !append(free, num_free, off))
 487                                 return false;
 488                 } else {
 489                         uint64_t klen, dlen, extra;
 490
 491                         /* This record is used! */
 492                         if (rec_magic(&p->u) != TDB_MAGIC) {
 493                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 494                                          "tdb_check: Bad magic 0x%llx"
 495                                          " at offset %llu\n",
 496                                          (long long)rec_magic(&p->u),
 497                                          (long long)off);
 498                                 return false;
 499                         }
 500
 501                         if (!append(used, num_used, off))
 502                                 return false;
 503
 504                         klen = rec_key_length(&p->u);
 505                         dlen = rec_data_length(&p->u);
 506                         extra = rec_extra_padding(&p->u);
 507
 508                         len = sizeof(p->u) + klen + dlen + extra;
 509                         if (off + len > tdb->map_size) {
 510                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 511                                          "tdb_check: used overlength %llu"
 512                                          " at offset %llu\n",
 513                                          (long long)len, (long long)off);
 514                                 return false;
 515                         }
 516
 517                         if (len < sizeof(p->f)) {
 518                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 519                                          "tdb_check: too short record %llu at"
 520                                          " %llu\n",
 521                                          (long long)len, (long long)off);
 522                                 return false;
 523                         }
 524                 }
 525         }
 526
 527         /* We must have found recovery area if there was one. */
 528         if (recovery != 0 && !found_recovery) {
 529                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 530                          "tdb_check: expected a recovery area at %zu\n",
 531                          (size_t)recovery);
 532                 return false;
 533         }
 534
 535         return true;
 536 }
 537
 538 int tdb_check(struct tdb_context *tdb,
 539               int (*check)(TDB_DATA key, TDB_DATA data, void *private_data),
 540               void *private_data)
 541 {
 542         tdb_off_t *free = NULL, *used = NULL, flist, recovery;
 543         size_t num_free = 0, num_used = 0, num_found = 0, num_flists = 0;
 544
 545         if (tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, false) != 0)
 546                 return -1;
 547
 548         if (tdb_lock_expand(tdb, F_RDLCK) != 0) {
 549                 tdb_allrecord_unlock(tdb, F_RDLCK);
 550                 return -1;
 551         }
 552
 553         if (!check_header(tdb, &recovery))
 554                 goto fail;
 555
 556         /* First we do a linear scan, checking all records. */
 557         if (!check_linear(tdb, &used, &num_used, &free, &num_free, recovery))
 558                 goto fail;
 559
 560         for (flist = first_flist(tdb); flist; flist = next_flist(tdb, flist)) {
 561                 if (flist == TDB_OFF_ERR)
 562                         goto fail;
 563                 if (!check_free_list(tdb, flist, free, num_free, &num_found))
 564                         goto fail;
 565                 num_flists++;
 566         }
 567
 568         /* FIXME: Check key uniqueness? */
 569         if (!check_hash(tdb, used, num_used, num_flists, check, private_data))
 570                 goto fail;
 571
 572         if (num_found != num_free) {
 573                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 574                          "tdb_check: Not all entries are in free table\n");
 575                 return -1;
 576         }
 577
 578         tdb_allrecord_unlock(tdb, F_RDLCK);
 579         tdb_unlock_expand(tdb, F_RDLCK);
 580         return 0;
 581
 582 fail:
 583         tdb_allrecord_unlock(tdb, F_RDLCK);
 584         tdb_unlock_expand(tdb, F_RDLCK);
 585         return -1;
 586 }