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)
  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         /* Don't check reserved: they *can* be used later. */
  61         return true;
  62 }
  63
  64 static bool check_hash_tree(struct tdb_context *tdb,
  65                             tdb_off_t off, unsigned int group_bits,
  66                             uint64_t hprefix,
  67                             unsigned hprefix_bits,
  68                             tdb_off_t used[],
  69                             size_t num_used,
  70                             size_t *num_found);
  71
  72 static bool check_hash_record(struct tdb_context *tdb,
  73                               tdb_off_t off,
  74                               uint64_t hprefix,
  75                               unsigned hprefix_bits,
  76                               tdb_off_t used[],
  77                               size_t num_used,
  78                               size_t *num_found)
  79 {
  80         struct tdb_used_record rec;
  81
  82         if (tdb_read_convert(tdb, off, &rec, sizeof(rec)) == -1)
  83                 return false;
  84
  85         if (rec_data_length(&rec)
  86             != sizeof(tdb_off_t) << TDB_SUBLEVEL_HASH_BITS) {
  87                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
  88                          "tdb_check: Bad hash table length %llu vs %llu\n",
  89                          (long long)rec_data_length(&rec),
  90                          (long long)sizeof(tdb_off_t)<<TDB_SUBLEVEL_HASH_BITS);
  91                 return false;
  92         }
  93         if (rec_key_length(&rec) != 0) {
  94                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
  95                          "tdb_check: Bad hash table key length %llu\n",
  96                          (long long)rec_key_length(&rec));
  97                 return false;
  98         }
  99         if (rec_hash(&rec) != 0) {
 100                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 101                          "tdb_check: Bad hash table hash value %llu\n",
 102                          (long long)rec_hash(&rec));
 103                 return false;
 104         }
 105
 106         off += sizeof(rec);
 107         return check_hash_tree(tdb, off,
 108                                TDB_SUBLEVEL_HASH_BITS-TDB_HASH_GROUP_BITS,
 109                                hprefix, hprefix_bits,
 110                                used, num_used, num_found);
 111 }
 112
 113 static int off_cmp(const tdb_off_t *a, const tdb_off_t *b)
 114 {
 115         /* Can overflow an int. */
 116         return *a > *b ? 1
 117                 : *a < *b ? -1
 118                 : 0;
 119 }
 120
 121 static uint64_t get_bits(uint64_t h, unsigned num, unsigned *used)
 122 {
 123         *used += num;
 124
 125         return (h >> (64 - *used)) & ((1U << num) - 1);
 126 }
 127
 128 static bool check_hash_tree(struct tdb_context *tdb,
 129                             tdb_off_t off, unsigned int group_bits,
 130                             uint64_t hprefix,
 131                             unsigned hprefix_bits,
 132                             tdb_off_t used[],
 133                             size_t num_used,
 134                             size_t *num_found)
 135 {
 136         unsigned int g, b;
 137         const tdb_off_t *hash;
 138         struct tdb_used_record rec;
 139
 140         hash = tdb_access_read(tdb, off,
 141                                sizeof(tdb_off_t)
 142                                << (group_bits + TDB_HASH_GROUP_BITS),
 143                                true);
 144         if (!hash)
 145                 return false;
 146
 147         for (g = 0; g < (1 << group_bits); g++) {
 148                 const tdb_off_t *group = hash + (g << TDB_HASH_GROUP_BITS);
 149                 for (b = 0; b < (1 << TDB_HASH_GROUP_BITS); b++) {
 150                         unsigned int bucket, i, used_bits;
 151                         uint64_t h;
 152                         tdb_off_t *p;
 153                         if (group[b] == 0)
 154                                 continue;
 155
 156                         off = group[b] & TDB_OFF_MASK;
 157                         p = asearch(&off, used, num_used, off_cmp);
 158                         if (!p) {
 159                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 160                                          "tdb_check: Invalid offset %llu "
 161                                          "in hash\n",
 162                                          (long long)off);
 163                                 goto fail;
 164                         }
 165                         /* Mark it invalid. */
 166                         *p ^= 1;
 167                         (*num_found)++;
 168
 169                         if (is_subhash(group[b])) {
 170                                 uint64_t subprefix;
 171                                 subprefix = (hprefix
 172                                      << (group_bits + TDB_HASH_GROUP_BITS))
 173                                         + g * (1 << TDB_HASH_GROUP_BITS) + b;
 174
 175                                 if (!check_hash_record(tdb,
 176                                                group[b] & TDB_OFF_MASK,
 177                                                subprefix,
 178                                                hprefix_bits
 179                                                        + group_bits
 180                                                        + TDB_HASH_GROUP_BITS,
 181                                                used, num_used, num_found))
 182                                         goto fail;
 183                                 continue;
 184                         }
 185                         /* A normal entry */
 186
 187                         /* Does it belong here at all? */
 188                         h = hash_record(tdb, off);
 189                         used_bits = 0;
 190                         if (get_bits(h, hprefix_bits, &used_bits) != hprefix
 191                             && hprefix_bits) {
 192                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 193                                          "check: bad hash placement"
 194                                          " 0x%llx vs 0x%llx\n",
 195                                          (long long)h, (long long)hprefix);
 196                                 goto fail;
 197                         }
 198
 199                         /* Does it belong in this group? */
 200                         if (get_bits(h, group_bits, &used_bits) != g) {
 201                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 202                                          "check: bad group %llu vs %u\n",
 203                                          (long long)h, g);
 204                                 goto fail;
 205                         }
 206
 207                         /* Are bucket bits correct? */
 208                         bucket = group[b] & TDB_OFF_HASH_GROUP_MASK;
 209                         if (get_bits(h, TDB_HASH_GROUP_BITS, &used_bits)
 210                             != bucket) {
 211                                 used_bits -= TDB_HASH_GROUP_BITS;
 212                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 213                                          "check: bad bucket %u vs %u\n",
 214                                          (unsigned)get_bits(h,
 215                                                             TDB_HASH_GROUP_BITS,
 216                                                             &used_bits),
 217                                          bucket);
 218                                 goto fail;
 219                         }
 220
 221                         /* There must not be any zero entries between
 222                          * the bucket it belongs in and this one! */
 223                         for (i = bucket;
 224                              i != b;
 225                              i = (i + 1) % (1 << TDB_HASH_GROUP_BITS)) {
 226                                 if (group[i] == 0) {
 227                                         tdb->log(tdb, TDB_DEBUG_ERROR,
 228                                                  tdb->log_priv,
 229                                                  "check: bad group placement"
 230                                                  " %u vs %u\n",
 231                                                  b, bucket);
 232                                         goto fail;
 233                                 }
 234                         }
 235
 236                         if (tdb_read_convert(tdb, off, &rec, sizeof(rec)) == -1)
 237                                 goto fail;
 238
 239                         /* Bottom bits must match header. */
 240                         if ((h & ((1 << 5)-1)) != rec_hash(&rec)) {
 241                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 242                                          "tdb_check: Bad hash magic at"
 243                                          " offset %llu (0x%llx vs 0x%llx)\n",
 244                                          (long long)off,
 245                                          (long long)h,
 246                                          (long long)rec_hash(&rec));
 247                                 goto fail;
 248                         }
 249                 }
 250         }
 251         tdb_access_release(tdb, hash);
 252         return true;
 253
 254 fail:
 255         tdb_access_release(tdb, hash);
 256         return false;
 257 }
 258
 259 static bool check_hash(struct tdb_context *tdb,
 260                        tdb_off_t used[],
 261                        size_t num_used)
 262 {
 263         size_t num_found = 0;
 264
 265         if (!check_hash_tree(tdb, offsetof(struct tdb_header, hashtable),
 266                              TDB_TOPLEVEL_HASH_BITS-TDB_HASH_GROUP_BITS,
 267                              0, 0, used, num_used, &num_found))
 268                 return false;
 269
 270         if (num_found != num_used) {
 271                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 272                          "tdb_check: Not all entries are in hash\n");
 273                 return false;
 274         }
 275         return true;
 276 }
 277
 278 static bool check_free(struct tdb_context *tdb,
 279                        tdb_off_t off,
 280                        const struct tdb_free_record *frec,
 281                        tdb_off_t prev,
 282                        tdb_off_t zone_off, unsigned int bucket)
 283 {
 284         if (frec_magic(frec) != TDB_FREE_MAGIC) {
 285                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 286                          "tdb_check: offset %llu bad magic 0x%llx\n",
 287                          (long long)off, (long long)frec->magic_and_meta);
 288                 return false;
 289         }
 290         if (tdb->methods->oob(tdb, off
 291                               + frec->data_len+sizeof(struct tdb_used_record),
 292                               false))
 293                 return false;
 294         if (off < zone_off || off >= zone_off + (1ULL<<frec_zone_bits(frec))) {
 295                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 296                          "tdb_check: offset %llu outside zone %llu-%llu\n",
 297                          (long long)off,
 298                          (long long)zone_off,
 299                          (long long)zone_off + (1ULL<<frec_zone_bits(frec)));
 300                 return false;
 301         }
 302         if (size_to_bucket(frec_zone_bits(frec), frec->data_len) != bucket) {
 303                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 304                          "tdb_check: offset %llu in wrong bucket %u vs %u\n",
 305                          (long long)off,
 306                          bucket,
 307                          size_to_bucket(frec_zone_bits(frec), frec->data_len));
 308                 return false;
 309         }
 310         if (prev != frec->prev) {
 311                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 312                          "tdb_check: offset %llu bad prev %llu vs %llu\n",
 313                          (long long)off,
 314                          (long long)prev, (long long)frec->prev);
 315                 return false;
 316         }
 317         return true;
 318 }
 319
 320 static tdb_len_t check_free_list(struct tdb_context *tdb,
 321                                  tdb_off_t zone_off,
 322                                  tdb_off_t free[],
 323                                  size_t num_free,
 324                                  size_t *num_found)
 325 {
 326         struct free_zone_header zhdr;
 327         tdb_off_t h;
 328         unsigned int i;
 329
 330         if (tdb_read_convert(tdb, zone_off, &zhdr, sizeof(zhdr)) == -1)
 331                 return TDB_OFF_ERR;
 332
 333         for (i = 0; i <= BUCKETS_FOR_ZONE(zhdr.zone_bits); i++) {
 334                 tdb_off_t off, prev = 0, *p;
 335                 struct tdb_free_record f;
 336
 337                 h = bucket_off(zone_off, i);
 338                 for (off = tdb_read_off(tdb, h); off; off = f.next) {
 339                         if (off == TDB_OFF_ERR)
 340                                 return TDB_OFF_ERR;
 341                         if (tdb_read_convert(tdb, off, &f, sizeof(f)))
 342                                 return TDB_OFF_ERR;
 343                         if (!check_free(tdb, off, &f, prev, zone_off, i))
 344                                 return TDB_OFF_ERR;
 345
 346                         /* FIXME: Check hash bits */
 347                         p = asearch(&off, free, num_free, off_cmp);
 348                         if (!p) {
 349                                 tdb->log(tdb, TDB_DEBUG_ERROR,
 350                                          tdb->log_priv,
 351                                          "tdb_check: Invalid offset"
 352                                          " %llu in free table\n",
 353                                          (long long)off);
 354                                 return TDB_OFF_ERR;
 355                         }
 356                         /* Mark it invalid. */
 357                         *p ^= 1;
 358                         (*num_found)++;
 359                         prev = off;
 360                 }
 361         }
 362         return 1ULL << zhdr.zone_bits;
 363 }
 364
 365 static tdb_off_t check_zone(struct tdb_context *tdb, tdb_off_t zone_off,
 366                             tdb_off_t **used, size_t *num_used,
 367                             tdb_off_t **free, size_t *num_free,
 368                             unsigned int *max_zone_bits)
 369 {
 370         struct free_zone_header zhdr;
 371         tdb_off_t off, hdrlen;
 372         tdb_len_t len;
 373
 374         if (tdb_read_convert(tdb, zone_off, &zhdr, sizeof(zhdr)) == -1)
 375                 return TDB_OFF_ERR;
 376
 377         if (zhdr.zone_bits < INITIAL_ZONE_BITS) {
 378                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 379                          "check: bad zone_bits %llu at zone %llu\n",
 380                          (long long)zhdr.zone_bits, (long long)zone_off);
 381                 return TDB_OFF_ERR;
 382         }
 383
 384         /* Zone bits can only increase... */
 385         if (zhdr.zone_bits > *max_zone_bits)
 386                 *max_zone_bits = zhdr.zone_bits;
 387         else if (zhdr.zone_bits < *max_zone_bits) {
 388                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 389                          "check: small zone_bits %llu at zone %llu\n",
 390                          (long long)zhdr.zone_bits, (long long)zone_off);
 391                 return TDB_OFF_ERR;
 392         }
 393
 394         /* Zone must be within file! */
 395         if (tdb->methods->oob(tdb, zone_off + (1ULL << zhdr.zone_bits), false))
 396                 return TDB_OFF_ERR;
 397
 398         hdrlen = sizeof(zhdr)
 399                 + (BUCKETS_FOR_ZONE(zhdr.zone_bits) + 1) * sizeof(tdb_off_t);
 400         for (off = zone_off + hdrlen;
 401              off < zone_off + (1ULL << zhdr.zone_bits);
 402              off += len) {
 403                 union {
 404                         struct tdb_used_record u;
 405                         struct tdb_free_record f;
 406                 } pad, *p;
 407                 p = tdb_get(tdb, off, &pad, sizeof(pad));
 408                 if (!p)
 409                         return TDB_OFF_ERR;
 410                 if (frec_magic(&p->f) == TDB_FREE_MAGIC) {
 411                         if (frec_zone_bits(&p->f) != zhdr.zone_bits) {
 412                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 413                                          "tdb_check: Bad free zone bits %u"
 414                                          " at offset %llu\n",
 415                                          frec_zone_bits(&p->f),
 416                                          (long long)off);
 417                                 return TDB_OFF_ERR;
 418                         }
 419                         /* This record is free! */
 420                         if (!append(free, num_free, off))
 421                                 return TDB_OFF_ERR;
 422                         len = sizeof(p->u) + p->f.data_len;
 423                         if (off + len > zone_off + (1ULL << zhdr.zone_bits)) {
 424                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 425                                          "tdb_check: free overlength %llu"
 426                                          " at offset %llu\n",
 427                                          (long long)len, (long long)off);
 428                                 return TDB_OFF_ERR;
 429                         }
 430                 } else {
 431                         uint64_t klen, dlen, extra;
 432
 433                         /* This record is used! */
 434                         if (rec_magic(&p->u) != TDB_MAGIC) {
 435                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 436                                          "tdb_check: Bad magic 0x%llx"
 437                                          " at offset %llu\n",
 438                                          (long long)rec_magic(&p->u),
 439                                          (long long)off);
 440                                 return TDB_OFF_ERR;
 441                         }
 442
 443                         if (rec_zone_bits(&p->u) != zhdr.zone_bits) {
 444                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 445                                          "tdb_check: Bad zone bits %u"
 446                                          " at offset %llu\n",
 447                                          rec_zone_bits(&p->u),
 448                                          (long long)off);
 449                                 return TDB_OFF_ERR;
 450                         }
 451
 452                         if (!append(used, num_used, off))
 453                                 return TDB_OFF_ERR;
 454
 455                         klen = rec_key_length(&p->u);
 456                         dlen = rec_data_length(&p->u);
 457                         extra = rec_extra_padding(&p->u);
 458
 459                         len = sizeof(p->u) + klen + dlen + extra;
 460                         if (off + len > zone_off + (1ULL << zhdr.zone_bits)) {
 461                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 462                                          "tdb_check: used overlength %llu"
 463                                          " at offset %llu\n",
 464                                          (long long)len, (long long)off);
 465                                 return TDB_OFF_ERR;
 466                         }
 467
 468                         if (len < sizeof(p->f)) {
 469                                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 470                                          "tdb_check: too short record %llu at"
 471                                          " %llu\n",
 472                                          (long long)len, (long long)off);
 473                                 return TDB_OFF_ERR;
 474                         }
 475                 }
 476         }
 477         return 1ULL << zhdr.zone_bits;
 478 }
 479
 480 /* FIXME: call check() function. */
 481 int tdb_check(struct tdb_context *tdb,
 482               int (*check)(TDB_DATA key, TDB_DATA data, void *private_data),
 483               void *private_data)
 484 {
 485         tdb_off_t *free = NULL, *used = NULL, off;
 486         tdb_len_t len;
 487         size_t num_free = 0, num_used = 0, num_found = 0;
 488         unsigned max_zone_bits = INITIAL_ZONE_BITS;
 489         uint8_t tailer;
 490
 491         if (tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, false) != 0)
 492                 return -1;
 493
 494         if (tdb_lock_expand(tdb, F_RDLCK) != 0) {
 495                 tdb_allrecord_unlock(tdb, F_RDLCK);
 496                 return -1;
 497         }
 498
 499         if (!check_header(tdb))
 500                 goto fail;
 501
 502         /* First we do a linear scan, checking all records. */
 503         for (off = sizeof(struct tdb_header);
 504              off < tdb->map_size - 1;
 505              off += len) {
 506                 len = check_zone(tdb, off, &used, &num_used, &free, &num_free,
 507                                  &max_zone_bits);
 508                 if (len == TDB_OFF_ERR)
 509                         goto fail;
 510         }
 511
 512         /* Check tailer. */
 513         if (tdb->methods->read(tdb, tdb->map_size - 1, &tailer, 1) == -1)
 514                 goto fail;
 515         if (tailer != max_zone_bits) {
 516                 tdb->ecode = TDB_ERR_CORRUPT;
 517                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 518                          "tdb_check: Bad tailer value %u vs %u\n", tailer,
 519                          max_zone_bits);
 520                 goto fail;
 521         }
 522
 523         /* FIXME: Check key uniqueness? */
 524         if (!check_hash(tdb, used, num_used))
 525                 goto fail;
 526
 527         for (off = sizeof(struct tdb_header);
 528              off < tdb->map_size - 1;
 529              off += len) {
 530                 len = check_free_list(tdb, off, free, num_free, &num_found);
 531                 if (len == TDB_OFF_ERR)
 532                         goto fail;
 533         }
 534         if (num_found != num_free) {
 535                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 536                          "tdb_check: Not all entries are in free table\n");
 537                 return false;
 538         }
 539
 540         tdb_allrecord_unlock(tdb, F_RDLCK);
 541         tdb_unlock_expand(tdb, F_RDLCK);
 542         return 0;
 543
 544 fail:
 545         tdb_allrecord_unlock(tdb, F_RDLCK);
 546         tdb_unlock_expand(tdb, F_RDLCK);
 547         return -1;
 548 }