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

   1 #include "private.h"
   2 #include <ccan/tdb2/tdb2.h>
   3 #include <ccan/build_assert/build_assert.h>
   4 #include <ccan/likely/likely.h>
   5 #include <assert.h>
   6
   7 /* The null return. */
   8 struct tdb_data tdb_null = { .dptr = NULL, .dsize = 0 };
   9
  10 /* all contexts, to ensure no double-opens (fcntl locks don't nest!) */
  11 static struct tdb_context *tdbs = NULL;
  12
  13 PRINTF_FMT(4, 5) static void
  14 null_log_fn(struct tdb_context *tdb,
  15             enum tdb_debug_level level, void *priv,
  16             const char *fmt, ...)
  17 {
  18 }
  19
  20 static bool tdb_already_open(dev_t device, ino_t ino)
  21 {
  22         struct tdb_context *i;
  23
  24         for (i = tdbs; i; i = i->next) {
  25                 if (i->device == device && i->inode == ino) {
  26                         return true;
  27                 }
  28         }
  29
  30         return false;
  31 }
  32
  33 static uint64_t random_number(struct tdb_context *tdb)
  34 {
  35         int fd;
  36         uint64_t ret = 0;
  37         struct timeval now;
  38
  39         fd = open("/dev/urandom", O_RDONLY);
  40         if (fd >= 0) {
  41                 if (tdb_read_all(fd, &ret, sizeof(ret))) {
  42                         tdb->log(tdb, TDB_DEBUG_TRACE, tdb->log_priv,
  43                                  "tdb_open: random from /dev/urandom\n");
  44                         close(fd);
  45                         return ret;
  46                 }
  47                 close(fd);
  48         }
  49         /* FIXME: Untested!  Based on Wikipedia protocol description! */
  50         fd = open("/dev/egd-pool", O_RDWR);
  51         if (fd >= 0) {
  52                 /* Command is 1, next byte is size we want to read. */
  53                 char cmd[2] = { 1, sizeof(uint64_t) };
  54                 if (write(fd, cmd, sizeof(cmd)) == sizeof(cmd)) {
  55                         char reply[1 + sizeof(uint64_t)];
  56                         int r = read(fd, reply, sizeof(reply));
  57                         if (r > 1) {
  58                                 tdb->log(tdb, TDB_DEBUG_TRACE, tdb->log_priv,
  59                                          "tdb_open: %u random bytes from"
  60                                          " /dev/egd-pool\n", r-1);
  61                                 /* Copy at least some bytes. */
  62                                 memcpy(&ret, reply+1, r - 1);
  63                                 if (reply[0] == sizeof(uint64_t)
  64                                     && r == sizeof(reply)) {
  65                                         close(fd);
  66                                         return ret;
  67                                 }
  68                         }
  69                 }
  70                 close(fd);
  71         }
  72
  73         /* Fallback: pid and time. */
  74         gettimeofday(&now, NULL);
  75         ret = getpid() * 100132289ULL + now.tv_sec * 1000000ULL + now.tv_usec;
  76         tdb->log(tdb, TDB_DEBUG_TRACE, tdb->log_priv,
  77                  "tdb_open: random from getpid and time\n");
  78         return ret;
  79 }
  80
  81 struct new_database {
  82         struct tdb_header hdr;
  83         struct tdb_freelist flist;
  84 };
  85
  86 /* initialise a new database */
  87 static int tdb_new_database(struct tdb_context *tdb,
  88                             struct tdb_attribute_seed *seed,
  89                             struct tdb_header *hdr)
  90 {
  91         /* We make it up in memory, then write it out if not internal */
  92         struct new_database newdb;
  93         unsigned int magic_len;
  94
  95         /* Fill in the header */
  96         newdb.hdr.version = TDB_VERSION;
  97         if (seed)
  98                 newdb.hdr.hash_seed = seed->seed;
  99         else
 100                 newdb.hdr.hash_seed = random_number(tdb);
 101         newdb.hdr.hash_test = TDB_HASH_MAGIC;
 102         newdb.hdr.hash_test = tdb->khash(&newdb.hdr.hash_test,
 103                                          sizeof(newdb.hdr.hash_test),
 104                                          newdb.hdr.hash_seed,
 105                                          tdb->hash_priv);
 106         memset(newdb.hdr.reserved, 0, sizeof(newdb.hdr.reserved));
 107         /* Initial hashes are empty. */
 108         memset(newdb.hdr.hashtable, 0, sizeof(newdb.hdr.hashtable));
 109
 110         /* Free is empty. */
 111         newdb.hdr.free_list = offsetof(struct new_database, flist);
 112         memset(&newdb.flist, 0, sizeof(newdb.flist));
 113         set_header(NULL, &newdb.flist.hdr, 0,
 114                    sizeof(newdb.flist.buckets), sizeof(newdb.flist.buckets), 1);
 115
 116         /* Magic food */
 117         memset(newdb.hdr.magic_food, 0, sizeof(newdb.hdr.magic_food));
 118         strcpy(newdb.hdr.magic_food, TDB_MAGIC_FOOD);
 119
 120         /* This creates an endian-converted database, as if read from disk */
 121         magic_len = sizeof(newdb.hdr.magic_food);
 122         tdb_convert(tdb,
 123                     (char *)&newdb.hdr + magic_len, sizeof(newdb) - magic_len);
 124
 125         *hdr = newdb.hdr;
 126
 127         if (tdb->flags & TDB_INTERNAL) {
 128                 tdb->map_size = sizeof(newdb);
 129                 tdb->map_ptr = malloc(tdb->map_size);
 130                 if (!tdb->map_ptr) {
 131                         tdb->ecode = TDB_ERR_OOM;
 132                         return -1;
 133                 }
 134                 memcpy(tdb->map_ptr, &newdb, tdb->map_size);
 135                 return 0;
 136         }
 137         if (lseek(tdb->fd, 0, SEEK_SET) == -1)
 138                 return -1;
 139
 140         if (ftruncate(tdb->fd, 0) == -1)
 141                 return -1;
 142
 143         if (!tdb_pwrite_all(tdb->fd, &newdb, sizeof(newdb), 0)) {
 144                 tdb->ecode = TDB_ERR_IO;
 145                 return -1;
 146         }
 147         return 0;
 148 }
 149
 150 struct tdb_context *tdb_open(const char *name, int tdb_flags,
 151                              int open_flags, mode_t mode,
 152                              union tdb_attribute *attr)
 153 {
 154         struct tdb_context *tdb;
 155         struct stat st;
 156         int save_errno;
 157         uint64_t hash_test;
 158         unsigned v;
 159         struct tdb_header hdr;
 160         struct tdb_attribute_seed *seed = NULL;
 161
 162         tdb = malloc(sizeof(*tdb));
 163         if (!tdb) {
 164                 /* Can't log this */
 165                 errno = ENOMEM;
 166                 goto fail;
 167         }
 168         tdb->name = NULL;
 169         tdb->map_ptr = NULL;
 170         tdb->direct_access = 0;
 171         tdb->fd = -1;
 172         tdb->map_size = sizeof(struct tdb_header);
 173         tdb->ecode = TDB_SUCCESS;
 174         tdb->flags = tdb_flags;
 175         tdb->log = null_log_fn;
 176         tdb->log_priv = NULL;
 177         tdb->transaction = NULL;
 178         tdb_hash_init(tdb);
 179         tdb_io_init(tdb);
 180         tdb_lock_init(tdb);
 181
 182         while (attr) {
 183                 switch (attr->base.attr) {
 184                 case TDB_ATTRIBUTE_LOG:
 185                         tdb->log = attr->log.log_fn;
 186                         tdb->log_priv = attr->log.log_private;
 187                         break;
 188                 case TDB_ATTRIBUTE_HASH:
 189                         tdb->khash = attr->hash.hash_fn;
 190                         tdb->hash_priv = attr->hash.hash_private;
 191                         break;
 192                 case TDB_ATTRIBUTE_SEED:
 193                         seed = &attr->seed;
 194                         break;
 195                 default:
 196                         tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 197                                  "tdb_open: unknown attribute type %u\n",
 198                                  attr->base.attr);
 199                         errno = EINVAL;
 200                         goto fail;
 201                 }
 202                 attr = attr->base.next;
 203         }
 204
 205         if ((open_flags & O_ACCMODE) == O_WRONLY) {
 206                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 207                          "tdb_open: can't open tdb %s write-only\n", name);
 208                 errno = EINVAL;
 209                 goto fail;
 210         }
 211
 212         if ((open_flags & O_ACCMODE) == O_RDONLY) {
 213                 tdb->read_only = true;
 214                 /* read only databases don't do locking */
 215                 tdb->flags |= TDB_NOLOCK;
 216                 tdb->mmap_flags = PROT_READ;
 217         } else {
 218                 tdb->read_only = false;
 219                 tdb->mmap_flags = PROT_READ | PROT_WRITE;
 220         }
 221
 222         /* internal databases don't need any of the rest. */
 223         if (tdb->flags & TDB_INTERNAL) {
 224                 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
 225                 if (tdb_new_database(tdb, seed, &hdr) != 0) {
 226                         tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 227                                  "tdb_open: tdb_new_database failed!");
 228                         goto fail;
 229                 }
 230                 tdb_convert(tdb, &hdr.hash_seed, sizeof(hdr.hash_seed));
 231                 tdb->hash_seed = hdr.hash_seed;
 232                 tdb_flist_init(tdb);
 233                 return tdb;
 234         }
 235
 236         if ((tdb->fd = open(name, open_flags, mode)) == -1) {
 237                 tdb->log(tdb, TDB_DEBUG_WARNING, tdb->log_priv,
 238                          "tdb_open: could not open file %s: %s\n",
 239                          name, strerror(errno));
 240                 goto fail;      /* errno set by open(2) */
 241         }
 242
 243         /* on exec, don't inherit the fd */
 244         v = fcntl(tdb->fd, F_GETFD, 0);
 245         fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);
 246
 247         /* ensure there is only one process initialising at once */
 248         if (tdb_lock_open(tdb) == -1) {
 249                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 250                          "tdb_open: failed to get open lock on %s: %s\n",
 251                          name, strerror(errno));
 252                 goto fail;      /* errno set by tdb_brlock */
 253         }
 254
 255         if (!tdb_pread_all(tdb->fd, &hdr, sizeof(hdr), 0)
 256             || strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0) {
 257                 if (!(open_flags & O_CREAT)
 258                     || tdb_new_database(tdb, seed, &hdr) == -1) {
 259                         if (errno == 0) {
 260                                 errno = EIO; /* ie bad format or something */
 261                         }
 262                         goto fail;
 263                 }
 264         } else if (hdr.version != TDB_VERSION) {
 265                 if (hdr.version == bswap_64(TDB_VERSION))
 266                         tdb->flags |= TDB_CONVERT;
 267                 else {
 268                         /* wrong version */
 269                         tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 270                                  "tdb_open: %s is unknown version 0x%llx\n",
 271                                  name, (long long)hdr.version);
 272                         errno = EIO;
 273                         goto fail;
 274                 }
 275         }
 276
 277         tdb_convert(tdb, &hdr, sizeof(hdr));
 278         tdb->hash_seed = hdr.hash_seed;
 279         hash_test = TDB_HASH_MAGIC;
 280         hash_test = tdb_hash(tdb, &hash_test, sizeof(hash_test));
 281         if (hdr.hash_test != hash_test) {
 282                 /* wrong hash variant */
 283                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 284                          "tdb_open: %s uses a different hash function\n",
 285                          name);
 286                 errno = EIO;
 287                 goto fail;
 288         }
 289
 290         if (fstat(tdb->fd, &st) == -1)
 291                 goto fail;
 292
 293         /* Is it already in the open list?  If so, fail. */
 294         if (tdb_already_open(st.st_dev, st.st_ino)) {
 295                 /* FIXME */
 296                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 297                          "tdb_open: %s (%d,%d) is already open in this process\n",
 298                          name, (int)st.st_dev, (int)st.st_ino);
 299                 errno = EBUSY;
 300                 goto fail;
 301         }
 302
 303         tdb->name = strdup(name);
 304         if (!tdb->name) {
 305                 errno = ENOMEM;
 306                 goto fail;
 307         }
 308
 309         tdb->device = st.st_dev;
 310         tdb->inode = st.st_ino;
 311         tdb_unlock_open(tdb);
 312
 313         /* This make sure we have current map_size and mmap. */
 314         tdb->methods->oob(tdb, tdb->map_size + 1, true);
 315
 316         if (tdb_flist_init(tdb) == -1)
 317                 goto fail;
 318
 319         tdb->next = tdbs;
 320         tdbs = tdb;
 321         return tdb;
 322
 323  fail:
 324         save_errno = errno;
 325
 326         if (!tdb)
 327                 return NULL;
 328
 329 #ifdef TDB_TRACE
 330         close(tdb->tracefd);
 331 #endif
 332         if (tdb->map_ptr) {
 333                 if (tdb->flags & TDB_INTERNAL) {
 334                         free(tdb->map_ptr);
 335                 } else
 336                         tdb_munmap(tdb);
 337         }
 338         free((char *)tdb->name);
 339         if (tdb->fd != -1)
 340                 if (close(tdb->fd) != 0)
 341                         tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 342                                  "tdb_open: failed to close tdb->fd"
 343                                  " on error!\n");
 344         free(tdb);
 345         errno = save_errno;
 346         return NULL;
 347 }
 348
 349 /* FIXME: modify, don't rewrite! */
 350 static int update_rec_hdr(struct tdb_context *tdb,
 351                           tdb_off_t off,
 352                           tdb_len_t keylen,
 353                           tdb_len_t datalen,
 354                           struct tdb_used_record *rec,
 355                           uint64_t h)
 356 {
 357         uint64_t dataroom = rec_data_length(rec) + rec_extra_padding(rec);
 358
 359         if (set_header(tdb, rec, keylen, datalen, keylen + dataroom, h))
 360                 return -1;
 361
 362         return tdb_write_convert(tdb, off, rec, sizeof(*rec));
 363 }
 364
 365 /* Returns -1 on error, 0 on OK */
 366 static int replace_data(struct tdb_context *tdb,
 367                         struct hash_info *h,
 368                         struct tdb_data key, struct tdb_data dbuf,
 369                         tdb_off_t old_off, tdb_len_t old_room,
 370                         bool growing)
 371 {
 372         tdb_off_t new_off;
 373
 374         /* Allocate a new record. */
 375         new_off = alloc(tdb, key.dsize, dbuf.dsize, h->h, growing);
 376         if (unlikely(new_off == TDB_OFF_ERR))
 377                 return -1;
 378
 379         /* We didn't like the existing one: remove it. */
 380         if (old_off) {
 381                 add_free_record(tdb, old_off,
 382                                 sizeof(struct tdb_used_record)
 383                                 + key.dsize + old_room);
 384                 if (replace_in_hash(tdb, h, new_off) == -1)
 385                         return -1;
 386         } else {
 387                 if (add_to_hash(tdb, h, new_off) == -1)
 388                         return -1;
 389         }
 390
 391         new_off += sizeof(struct tdb_used_record);
 392         if (tdb->methods->write(tdb, new_off, key.dptr, key.dsize) == -1)
 393                 return -1;
 394
 395         new_off += key.dsize;
 396         if (tdb->methods->write(tdb, new_off, dbuf.dptr, dbuf.dsize) == -1)
 397                 return -1;
 398
 399         /* FIXME: tdb_increment_seqnum(tdb); */
 400         return 0;
 401 }
 402
 403 int tdb_store(struct tdb_context *tdb,
 404               struct tdb_data key, struct tdb_data dbuf, int flag)
 405 {
 406         struct hash_info h;
 407         tdb_off_t off;
 408         tdb_len_t old_room = 0;
 409         struct tdb_used_record rec;
 410         int ret;
 411
 412         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 413         if (unlikely(off == TDB_OFF_ERR))
 414                 return -1;
 415
 416         /* Now we have lock on this hash bucket. */
 417         if (flag == TDB_INSERT) {
 418                 if (off) {
 419                         tdb->ecode = TDB_ERR_EXISTS;
 420                         goto fail;
 421                 }
 422         } else {
 423                 if (off) {
 424                         old_room = rec_data_length(&rec)
 425                                 + rec_extra_padding(&rec);
 426                         if (old_room >= dbuf.dsize) {
 427                                 /* Can modify in-place.  Easy! */
 428                                 if (update_rec_hdr(tdb, off,
 429                                                    key.dsize, dbuf.dsize,
 430                                                    &rec, h.h))
 431                                         goto fail;
 432                                 if (tdb->methods->write(tdb, off + sizeof(rec)
 433                                                         + key.dsize,
 434                                                         dbuf.dptr, dbuf.dsize))
 435                                         goto fail;
 436                                 tdb_unlock_hashes(tdb, h.hlock_start,
 437                                                   h.hlock_range, F_WRLCK);
 438                                 return 0;
 439                         }
 440                         /* FIXME: See if right record is free? */
 441                 } else {
 442                         if (flag == TDB_MODIFY) {
 443                                 /* if the record doesn't exist and we
 444                                    are in TDB_MODIFY mode then we should fail
 445                                    the store */
 446                                 tdb->ecode = TDB_ERR_NOEXIST;
 447                                 goto fail;
 448                         }
 449                 }
 450         }
 451
 452         /* If we didn't use the old record, this implies we're growing. */
 453         ret = replace_data(tdb, &h, key, dbuf, off, old_room, off != 0);
 454         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 455         return ret;
 456
 457 fail:
 458         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 459         return -1;
 460 }
 461
 462 int tdb_append(struct tdb_context *tdb,
 463                struct tdb_data key, struct tdb_data dbuf)
 464 {
 465         struct hash_info h;
 466         tdb_off_t off;
 467         struct tdb_used_record rec;
 468         tdb_len_t old_room = 0, old_dlen;
 469         unsigned char *newdata;
 470         struct tdb_data new_dbuf;
 471         int ret;
 472
 473         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 474         if (unlikely(off == TDB_OFF_ERR))
 475                 return -1;
 476
 477         if (off) {
 478                 old_dlen = rec_data_length(&rec);
 479                 old_room = old_dlen + rec_extra_padding(&rec);
 480
 481                 /* Fast path: can append in place. */
 482                 if (rec_extra_padding(&rec) >= dbuf.dsize) {
 483                         if (update_rec_hdr(tdb, off, key.dsize,
 484                                            old_dlen + dbuf.dsize, &rec, h.h))
 485                                 goto fail;
 486
 487                         off += sizeof(rec) + key.dsize + old_dlen;
 488                         if (tdb->methods->write(tdb, off, dbuf.dptr,
 489                                                 dbuf.dsize) == -1)
 490                                 goto fail;
 491
 492                         /* FIXME: tdb_increment_seqnum(tdb); */
 493                         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range,
 494                                           F_WRLCK);
 495                         return 0;
 496                 }
 497                 /* FIXME: Check right record free? */
 498
 499                 /* Slow path. */
 500                 newdata = malloc(key.dsize + old_dlen + dbuf.dsize);
 501                 if (!newdata) {
 502                         tdb->ecode = TDB_ERR_OOM;
 503                         tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
 504                                  "tdb_append: cannot allocate %llu bytes!\n",
 505                                  (long long)key.dsize + old_dlen + dbuf.dsize);
 506                         goto fail;
 507                 }
 508                 if (tdb->methods->read(tdb, off + sizeof(rec) + key.dsize,
 509                                        newdata, old_dlen) != 0) {
 510                         free(newdata);
 511                         goto fail;
 512                 }
 513                 memcpy(newdata + old_dlen, dbuf.dptr, dbuf.dsize);
 514                 new_dbuf.dptr = newdata;
 515                 new_dbuf.dsize = old_dlen + dbuf.dsize;
 516         } else {
 517                 newdata = NULL;
 518                 new_dbuf = dbuf;
 519         }
 520
 521         /* If they're using tdb_append(), it implies they're growing record. */
 522         ret = replace_data(tdb, &h, key, new_dbuf, off, old_room, true);
 523         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 524         free(newdata);
 525
 526         return ret;
 527
 528 fail:
 529         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 530         return -1;
 531 }
 532
 533 struct tdb_data tdb_fetch(struct tdb_context *tdb, struct tdb_data key)
 534 {
 535         tdb_off_t off;
 536         struct tdb_used_record rec;
 537         struct hash_info h;
 538         struct tdb_data ret;
 539
 540         off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
 541         if (unlikely(off == TDB_OFF_ERR))
 542                 return tdb_null;
 543
 544         if (!off) {
 545                 tdb->ecode = TDB_ERR_NOEXIST;
 546                 ret = tdb_null;
 547         } else {
 548                 ret.dsize = rec_data_length(&rec);
 549                 ret.dptr = tdb_alloc_read(tdb, off + sizeof(rec) + key.dsize,
 550                                           ret.dsize);
 551         }
 552
 553         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
 554         return ret;
 555 }
 556
 557 int tdb_delete(struct tdb_context *tdb, struct tdb_data key)
 558 {
 559         tdb_off_t off;
 560         struct tdb_used_record rec;
 561         struct hash_info h;
 562
 563         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 564         if (unlikely(off == TDB_OFF_ERR))
 565                 return -1;
 566
 567         if (!off) {
 568                 tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 569                 tdb->ecode = TDB_ERR_NOEXIST;
 570                 return -1;
 571         }
 572
 573         if (delete_from_hash(tdb, &h) == -1)
 574                 goto unlock_err;
 575
 576         /* Free the deleted entry. */
 577         if (add_free_record(tdb, off,
 578                             sizeof(struct tdb_used_record)
 579                             + rec_key_length(&rec)
 580                             + rec_data_length(&rec)
 581                             + rec_extra_padding(&rec)) != 0)
 582                 goto unlock_err;
 583
 584         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 585         return 0;
 586
 587 unlock_err:
 588         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 589         return -1;
 590 }
 591
 592 int tdb_close(struct tdb_context *tdb)
 593 {
 594         struct tdb_context **i;
 595         int ret = 0;
 596
 597         /* FIXME:
 598         if (tdb->transaction) {
 599                 tdb_transaction_cancel(tdb);
 600         }
 601         */
 602         tdb_trace(tdb, "tdb_close");
 603
 604         if (tdb->map_ptr) {
 605                 if (tdb->flags & TDB_INTERNAL)
 606                         free(tdb->map_ptr);
 607                 else
 608                         tdb_munmap(tdb);
 609         }
 610         free((char *)tdb->name);
 611         if (tdb->fd != -1) {
 612                 ret = close(tdb->fd);
 613                 tdb->fd = -1;
 614         }
 615         free(tdb->lockrecs);
 616
 617         /* Remove from contexts list */
 618         for (i = &tdbs; *i; i = &(*i)->next) {
 619                 if (*i == tdb) {
 620                         *i = tdb->next;
 621                         break;
 622                 }
 623         }
 624
 625 #ifdef TDB_TRACE
 626         close(tdb->tracefd);
 627 #endif
 628         free(tdb);
 629
 630         return ret;
 631 }
 632
 633 enum TDB_ERROR tdb_error(struct tdb_context *tdb)
 634 {
 635         return tdb->ecode;
 636 }
 637
 638 const char *tdb_errorstr(struct tdb_context *tdb)
 639 {
 640         /* Gcc warns if you miss a case in the switch, so use that. */
 641         switch (tdb->ecode) {
 642         case TDB_SUCCESS: return "Success";
 643         case TDB_ERR_CORRUPT: return "Corrupt database";
 644         case TDB_ERR_IO: return "IO Error";
 645         case TDB_ERR_LOCK: return "Locking error";
 646         case TDB_ERR_OOM: return "Out of memory";
 647         case TDB_ERR_EXISTS: return "Record exists";
 648         case TDB_ERR_NESTING: return "Transaction already started";
 649         case TDB_ERR_EINVAL: return "Invalid parameter";
 650         case TDB_ERR_NOEXIST: return "Record does not exist";
 651         case TDB_ERR_RDONLY: return "write not permitted";
 652         }
 653         return "Invalid error code";
 654 }