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_ATTRIBUTE(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         /* Initial free zone. */
  84         struct free_zone_header zhdr;
  85         tdb_off_t free[BUCKETS_FOR_ZONE(INITIAL_ZONE_BITS) + 1];
  86         struct tdb_free_record frec;
  87         /* Rest up to 1 << INITIAL_ZONE_BITS is empty. */
  88         char space[(1 << INITIAL_ZONE_BITS)
  89                    - sizeof(struct free_zone_header)
  90                    - sizeof(tdb_off_t) * (BUCKETS_FOR_ZONE(INITIAL_ZONE_BITS)+1)
  91                    - sizeof(struct tdb_free_record)];
  92         uint8_t tailer;
  93         /* Don't count final padding! */
  94 };
  95
  96 /* initialise a new database */
  97 static int tdb_new_database(struct tdb_context *tdb, struct tdb_header *hdr)
  98 {
  99         /* We make it up in memory, then write it out if not internal */
 100         struct new_database newdb;
 101         unsigned int bucket, magic_len, dbsize;
 102
 103         /* Don't want any extra padding! */
 104         dbsize = offsetof(struct new_database, tailer) + sizeof(newdb.tailer);
 105
 106         /* Fill in the header */
 107         newdb.hdr.version = TDB_VERSION;
 108         newdb.hdr.hash_seed = random_number(tdb);
 109         newdb.hdr.hash_test = TDB_HASH_MAGIC;
 110         newdb.hdr.hash_test = tdb->khash(&newdb.hdr.hash_test,
 111                                          sizeof(newdb.hdr.hash_test),
 112                                          newdb.hdr.hash_seed,
 113                                          tdb->hash_priv);
 114         memset(newdb.hdr.reserved, 0, sizeof(newdb.hdr.reserved));
 115         /* Initial hashes are empty. */
 116         memset(newdb.hdr.hashtable, 0, sizeof(newdb.hdr.hashtable));
 117
 118         /* Free is mostly empty... */
 119         newdb.zhdr.zone_bits = INITIAL_ZONE_BITS;
 120         memset(newdb.free, 0, sizeof(newdb.free));
 121
 122         /* Create the single free entry. */
 123         newdb.frec.magic_and_meta = TDB_FREE_MAGIC | INITIAL_ZONE_BITS;
 124         newdb.frec.data_len = (sizeof(newdb.frec)
 125                                  - sizeof(struct tdb_used_record)
 126                                  + sizeof(newdb.space));
 127
 128         /* Add it to the correct bucket. */
 129         bucket = size_to_bucket(INITIAL_ZONE_BITS, newdb.frec.data_len);
 130         newdb.free[bucket] = offsetof(struct new_database, frec);
 131         newdb.frec.next = newdb.frec.prev = 0;
 132
 133         /* Clear free space to keep valgrind happy, and avoid leaking stack. */
 134         memset(newdb.space, 0, sizeof(newdb.space));
 135
 136         /* Tailer contains maximum number of free_zone bits. */
 137         newdb.tailer = INITIAL_ZONE_BITS;
 138
 139         /* Magic food */
 140         memset(newdb.hdr.magic_food, 0, sizeof(newdb.hdr.magic_food));
 141         strcpy(newdb.hdr.magic_food, TDB_MAGIC_FOOD);
 142
 143         /* This creates an endian-converted database, as if read from disk */
 144         magic_len = sizeof(newdb.hdr.magic_food);
 145         tdb_convert(tdb,
 146                     (char *)&newdb.hdr + magic_len,
 147                     offsetof(struct new_database, space) - magic_len);
 148
 149         *hdr = newdb.hdr;
 150
 151         if (tdb->flags & TDB_INTERNAL) {
 152                 tdb->map_size = dbsize;
 153                 tdb->map_ptr = malloc(tdb->map_size);
 154                 if (!tdb->map_ptr) {
 155                         tdb->ecode = TDB_ERR_OOM;
 156                         return -1;
 157                 }
 158                 memcpy(tdb->map_ptr, &newdb, tdb->map_size);
 159                 return 0;
 160         }
 161         if (lseek(tdb->fd, 0, SEEK_SET) == -1)
 162                 return -1;
 163
 164         if (ftruncate(tdb->fd, 0) == -1)
 165                 return -1;
 166
 167         if (!tdb_pwrite_all(tdb->fd, &newdb, dbsize, 0)) {
 168                 tdb->ecode = TDB_ERR_IO;
 169                 return -1;
 170         }
 171         return 0;
 172 }
 173
 174 struct tdb_context *tdb_open(const char *name, int tdb_flags,
 175                              int open_flags, mode_t mode,
 176                              union tdb_attribute *attr)
 177 {
 178         struct tdb_context *tdb;
 179         struct stat st;
 180         int save_errno;
 181         uint64_t hash_test;
 182         unsigned v;
 183         struct tdb_header hdr;
 184
 185         tdb = malloc(sizeof(*tdb));
 186         if (!tdb) {
 187                 /* Can't log this */
 188                 errno = ENOMEM;
 189                 goto fail;
 190         }
 191         tdb->name = NULL;
 192         tdb->map_ptr = NULL;
 193         tdb->direct_access = 0;
 194         tdb->fd = -1;
 195         tdb->map_size = sizeof(struct tdb_header);
 196         tdb->ecode = TDB_SUCCESS;
 197         tdb->flags = tdb_flags;
 198         tdb->log = null_log_fn;
 199         tdb->log_priv = NULL;
 200         tdb->transaction = NULL;
 201         tdb_hash_init(tdb);
 202         /* last_zone will be set below. */
 203         tdb_io_init(tdb);
 204         tdb_lock_init(tdb);
 205
 206         while (attr) {
 207                 switch (attr->base.attr) {
 208                 case TDB_ATTRIBUTE_LOG:
 209                         tdb->log = attr->log.log_fn;
 210                         tdb->log_priv = attr->log.log_private;
 211                         break;
 212                 case TDB_ATTRIBUTE_HASH:
 213                         tdb->khash = attr->hash.hash_fn;
 214                         tdb->hash_priv = attr->hash.hash_private;
 215                         break;
 216                 default:
 217                         tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 218                                  "tdb_open: unknown attribute type %u\n",
 219                                  attr->base.attr);
 220                         errno = EINVAL;
 221                         goto fail;
 222                 }
 223                 attr = attr->base.next;
 224         }
 225
 226         if ((open_flags & O_ACCMODE) == O_WRONLY) {
 227                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 228                          "tdb_open: can't open tdb %s write-only\n", name);
 229                 errno = EINVAL;
 230                 goto fail;
 231         }
 232
 233         if ((open_flags & O_ACCMODE) == O_RDONLY) {
 234                 tdb->read_only = true;
 235                 /* read only databases don't do locking */
 236                 tdb->flags |= TDB_NOLOCK;
 237                 tdb->mmap_flags = PROT_READ;
 238         } else {
 239                 tdb->read_only = false;
 240                 tdb->mmap_flags = PROT_READ | PROT_WRITE;
 241         }
 242
 243         /* internal databases don't need any of the rest. */
 244         if (tdb->flags & TDB_INTERNAL) {
 245                 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
 246                 if (tdb_new_database(tdb, &hdr) != 0) {
 247                         tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 248                                  "tdb_open: tdb_new_database failed!");
 249                         goto fail;
 250                 }
 251                 tdb_convert(tdb, &hdr.hash_seed, sizeof(hdr.hash_seed));
 252                 tdb->hash_seed = hdr.hash_seed;
 253                 tdb_zone_init(tdb);
 254                 return tdb;
 255         }
 256
 257         if ((tdb->fd = open(name, open_flags, mode)) == -1) {
 258                 tdb->log(tdb, TDB_DEBUG_WARNING, tdb->log_priv,
 259                          "tdb_open: could not open file %s: %s\n",
 260                          name, strerror(errno));
 261                 goto fail;      /* errno set by open(2) */
 262         }
 263
 264         /* on exec, don't inherit the fd */
 265         v = fcntl(tdb->fd, F_GETFD, 0);
 266         fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);
 267
 268         /* ensure there is only one process initialising at once */
 269         if (tdb_lock_open(tdb) == -1) {
 270                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 271                          "tdb_open: failed to get open lock on %s: %s\n",
 272                          name, strerror(errno));
 273                 goto fail;      /* errno set by tdb_brlock */
 274         }
 275
 276         if (!tdb_pread_all(tdb->fd, &hdr, sizeof(hdr), 0)
 277             || strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0) {
 278                 if (!(open_flags & O_CREAT) || tdb_new_database(tdb, &hdr) == -1) {
 279                         if (errno == 0) {
 280                                 errno = EIO; /* ie bad format or something */
 281                         }
 282                         goto fail;
 283                 }
 284         } else if (hdr.version != TDB_VERSION) {
 285                 if (hdr.version == bswap_64(TDB_VERSION))
 286                         tdb->flags |= TDB_CONVERT;
 287                 else {
 288                         /* wrong version */
 289                         tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 290                                  "tdb_open: %s is unknown version 0x%llx\n",
 291                                  name, (long long)hdr.version);
 292                         errno = EIO;
 293                         goto fail;
 294                 }
 295         }
 296
 297         tdb_convert(tdb, &hdr, sizeof(hdr));
 298         tdb->hash_seed = hdr.hash_seed;
 299         hash_test = TDB_HASH_MAGIC;
 300         hash_test = tdb_hash(tdb, &hash_test, sizeof(hash_test));
 301         if (hdr.hash_test != hash_test) {
 302                 /* wrong hash variant */
 303                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 304                          "tdb_open: %s uses a different hash function\n",
 305                          name);
 306                 errno = EIO;
 307                 goto fail;
 308         }
 309
 310         if (fstat(tdb->fd, &st) == -1)
 311                 goto fail;
 312
 313         /* Is it already in the open list?  If so, fail. */
 314         if (tdb_already_open(st.st_dev, st.st_ino)) {
 315                 /* FIXME */
 316                 tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 317                          "tdb_open: %s (%d,%d) is already open in this process\n",
 318                          name, (int)st.st_dev, (int)st.st_ino);
 319                 errno = EBUSY;
 320                 goto fail;
 321         }
 322
 323         tdb->name = strdup(name);
 324         if (!tdb->name) {
 325                 errno = ENOMEM;
 326                 goto fail;
 327         }
 328
 329         tdb->device = st.st_dev;
 330         tdb->inode = st.st_ino;
 331         tdb_unlock_open(tdb);
 332
 333         /* This make sure we have current map_size and mmap. */
 334         tdb->methods->oob(tdb, tdb->map_size + 1, true);
 335
 336         /* Now we can pick a random free zone to start from. */
 337         if (tdb_zone_init(tdb) == -1)
 338                 goto fail;
 339
 340         tdb->next = tdbs;
 341         tdbs = tdb;
 342         return tdb;
 343
 344  fail:
 345         save_errno = errno;
 346
 347         if (!tdb)
 348                 return NULL;
 349
 350 #ifdef TDB_TRACE
 351         close(tdb->tracefd);
 352 #endif
 353         if (tdb->map_ptr) {
 354                 if (tdb->flags & TDB_INTERNAL) {
 355                         free(tdb->map_ptr);
 356                 } else
 357                         tdb_munmap(tdb);
 358         }
 359         free((char *)tdb->name);
 360         if (tdb->fd != -1)
 361                 if (close(tdb->fd) != 0)
 362                         tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
 363                                  "tdb_open: failed to close tdb->fd"
 364                                  " on error!\n");
 365         free(tdb);
 366         errno = save_errno;
 367         return NULL;
 368 }
 369
 370 /* FIXME: modify, don't rewrite! */
 371 static int update_rec_hdr(struct tdb_context *tdb,
 372                           tdb_off_t off,
 373                           tdb_len_t keylen,
 374                           tdb_len_t datalen,
 375                           struct tdb_used_record *rec,
 376                           uint64_t h)
 377 {
 378         uint64_t dataroom = rec_data_length(rec) + rec_extra_padding(rec);
 379
 380         if (set_header(tdb, rec, keylen, datalen, keylen + dataroom, h,
 381                        rec_zone_bits(rec)))
 382                 return -1;
 383
 384         return tdb_write_convert(tdb, off, rec, sizeof(*rec));
 385 }
 386
 387 /* Returns -1 on error, 0 on OK */
 388 static int replace_data(struct tdb_context *tdb,
 389                         struct hash_info *h,
 390                         struct tdb_data key, struct tdb_data dbuf,
 391                         tdb_off_t old_off, tdb_len_t old_room,
 392                         unsigned old_zone,
 393                         bool growing)
 394 {
 395         tdb_off_t new_off;
 396
 397         /* Allocate a new record. */
 398         new_off = alloc(tdb, key.dsize, dbuf.dsize, h->h, growing);
 399         if (unlikely(new_off == TDB_OFF_ERR))
 400                 return -1;
 401
 402         /* We didn't like the existing one: remove it. */
 403         if (old_off) {
 404                 add_free_record(tdb, old_zone, old_off,
 405                                 sizeof(struct tdb_used_record)
 406                                 + key.dsize + old_room);
 407                 if (replace_in_hash(tdb, h, new_off) == -1)
 408                         return -1;
 409         } else {
 410                 if (add_to_hash(tdb, h, new_off) == -1)
 411                         return -1;
 412         }
 413
 414         new_off += sizeof(struct tdb_used_record);
 415         if (tdb->methods->write(tdb, new_off, key.dptr, key.dsize) == -1)
 416                 return -1;
 417
 418         new_off += key.dsize;
 419         if (tdb->methods->write(tdb, new_off, dbuf.dptr, dbuf.dsize) == -1)
 420                 return -1;
 421
 422         /* FIXME: tdb_increment_seqnum(tdb); */
 423         return 0;
 424 }
 425
 426 int tdb_store(struct tdb_context *tdb,
 427               struct tdb_data key, struct tdb_data dbuf, int flag)
 428 {
 429         struct hash_info h;
 430         tdb_off_t off;
 431         tdb_len_t old_room = 0;
 432         struct tdb_used_record rec;
 433         int ret;
 434
 435         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 436         if (unlikely(off == TDB_OFF_ERR))
 437                 return -1;
 438
 439         /* Now we have lock on this hash bucket. */
 440         if (flag == TDB_INSERT) {
 441                 if (off) {
 442                         tdb->ecode = TDB_ERR_EXISTS;
 443                         goto fail;
 444                 }
 445         } else {
 446                 if (off) {
 447                         old_room = rec_data_length(&rec)
 448                                 + rec_extra_padding(&rec);
 449                         if (old_room >= dbuf.dsize) {
 450                                 /* Can modify in-place.  Easy! */
 451                                 if (update_rec_hdr(tdb, off,
 452                                                    key.dsize, dbuf.dsize,
 453                                                    &rec, h.h))
 454                                         goto fail;
 455                                 if (tdb->methods->write(tdb, off + sizeof(rec)
 456                                                         + key.dsize,
 457                                                         dbuf.dptr, dbuf.dsize))
 458                                         goto fail;
 459                                 tdb_unlock_hashes(tdb, h.hlock_start,
 460                                                   h.hlock_range, F_WRLCK);
 461                                 return 0;
 462                         }
 463                         /* FIXME: See if right record is free? */
 464                 } else {
 465                         if (flag == TDB_MODIFY) {
 466                                 /* if the record doesn't exist and we
 467                                    are in TDB_MODIFY mode then we should fail
 468                                    the store */
 469                                 tdb->ecode = TDB_ERR_NOEXIST;
 470                                 goto fail;
 471                         }
 472                 }
 473         }
 474
 475         /* If we didn't use the old record, this implies we're growing. */
 476         ret = replace_data(tdb, &h, key, dbuf, off, old_room,
 477                            rec_zone_bits(&rec), off != 0);
 478         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 479         return ret;
 480
 481 fail:
 482         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 483         return -1;
 484 }
 485
 486 int tdb_append(struct tdb_context *tdb,
 487                struct tdb_data key, struct tdb_data dbuf)
 488 {
 489         struct hash_info h;
 490         tdb_off_t off;
 491         struct tdb_used_record rec;
 492         tdb_len_t old_room = 0, old_dlen;
 493         unsigned char *newdata;
 494         struct tdb_data new_dbuf;
 495         int ret;
 496
 497         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 498         if (unlikely(off == TDB_OFF_ERR))
 499                 return -1;
 500
 501         if (off) {
 502                 old_dlen = rec_data_length(&rec);
 503                 old_room = old_dlen + rec_extra_padding(&rec);
 504
 505                 /* Fast path: can append in place. */
 506                 if (rec_extra_padding(&rec) >= dbuf.dsize) {
 507                         if (update_rec_hdr(tdb, off, key.dsize,
 508                                            old_dlen + dbuf.dsize, &rec, h.h))
 509                                 goto fail;
 510
 511                         off += sizeof(rec) + key.dsize + old_dlen;
 512                         if (tdb->methods->write(tdb, off, dbuf.dptr,
 513                                                 dbuf.dsize) == -1)
 514                                 goto fail;
 515
 516                         /* FIXME: tdb_increment_seqnum(tdb); */
 517                         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range,
 518                                           F_WRLCK);
 519                         return 0;
 520                 }
 521                 /* FIXME: Check right record free? */
 522
 523                 /* Slow path. */
 524                 newdata = malloc(key.dsize + old_dlen + dbuf.dsize);
 525                 if (!newdata) {
 526                         tdb->ecode = TDB_ERR_OOM;
 527                         tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
 528                                  "tdb_append: cannot allocate %llu bytes!\n",
 529                                  (long long)key.dsize + old_dlen + dbuf.dsize);
 530                         goto fail;
 531                 }
 532                 if (tdb->methods->read(tdb, off + sizeof(rec) + key.dsize,
 533                                        newdata, old_dlen) != 0) {
 534                         free(newdata);
 535                         goto fail;
 536                 }
 537                 memcpy(newdata + old_dlen, dbuf.dptr, dbuf.dsize);
 538                 new_dbuf.dptr = newdata;
 539                 new_dbuf.dsize = old_dlen + dbuf.dsize;
 540         } else {
 541                 newdata = NULL;
 542                 new_dbuf = dbuf;
 543         }
 544
 545         /* If they're using tdb_append(), it implies they're growing record. */
 546         ret = replace_data(tdb, &h, key, new_dbuf, off,
 547                            old_room, rec_zone_bits(&rec), true);
 548         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 549         free(newdata);
 550
 551         return ret;
 552
 553 fail:
 554         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 555         return -1;
 556 }
 557
 558 struct tdb_data tdb_fetch(struct tdb_context *tdb, struct tdb_data key)
 559 {
 560         tdb_off_t off;
 561         struct tdb_used_record rec;
 562         struct hash_info h;
 563         struct tdb_data ret;
 564
 565         off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
 566         if (unlikely(off == TDB_OFF_ERR))
 567                 return tdb_null;
 568
 569         if (!off) {
 570                 tdb->ecode = TDB_ERR_NOEXIST;
 571                 ret = tdb_null;
 572         } else {
 573                 ret.dsize = rec_data_length(&rec);
 574                 ret.dptr = tdb_alloc_read(tdb, off + sizeof(rec) + key.dsize,
 575                                           ret.dsize);
 576         }
 577
 578         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
 579         return ret;
 580 }
 581
 582 int tdb_delete(struct tdb_context *tdb, struct tdb_data key)
 583 {
 584         tdb_off_t off;
 585         struct tdb_used_record rec;
 586         struct hash_info h;
 587
 588         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 589         if (unlikely(off == TDB_OFF_ERR))
 590                 return -1;
 591
 592         if (!off) {
 593                 tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 594                 tdb->ecode = TDB_ERR_NOEXIST;
 595                 return -1;
 596         }
 597
 598         if (delete_from_hash(tdb, &h) == -1)
 599                 goto unlock_err;
 600
 601         /* Free the deleted entry. */
 602         if (add_free_record(tdb, rec_zone_bits(&rec), off,
 603                             sizeof(struct tdb_used_record)
 604                             + rec_key_length(&rec)
 605                             + rec_data_length(&rec)
 606                             + rec_extra_padding(&rec)) != 0)
 607                 goto unlock_err;
 608
 609         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 610         return 0;
 611
 612 unlock_err:
 613         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 614         return -1;
 615 }
 616
 617 int tdb_close(struct tdb_context *tdb)
 618 {
 619         struct tdb_context **i;
 620         int ret = 0;
 621
 622         /* FIXME:
 623         if (tdb->transaction) {
 624                 tdb_transaction_cancel(tdb);
 625         }
 626         */
 627         tdb_trace(tdb, "tdb_close");
 628
 629         if (tdb->map_ptr) {
 630                 if (tdb->flags & TDB_INTERNAL)
 631                         free(tdb->map_ptr);
 632                 else
 633                         tdb_munmap(tdb);
 634         }
 635         free((char *)tdb->name);
 636         if (tdb->fd != -1) {
 637                 ret = close(tdb->fd);
 638                 tdb->fd = -1;
 639         }
 640         free(tdb->lockrecs);
 641
 642         /* Remove from contexts list */
 643         for (i = &tdbs; *i; i = &(*i)->next) {
 644                 if (*i == tdb) {
 645                         *i = tdb->next;
 646                         break;
 647                 }
 648         }
 649
 650 #ifdef TDB_TRACE
 651         close(tdb->tracefd);
 652 #endif
 653         free(tdb);
 654
 655         return ret;
 656 }
 657
 658 enum TDB_ERROR tdb_error(struct tdb_context *tdb)
 659 {
 660         return tdb->ecode;
 661 }
 662
 663 const char *tdb_errorstr(struct tdb_context *tdb)
 664 {
 665         /* Gcc warns if you miss a case in the switch, so use that. */
 666         switch (tdb->ecode) {
 667         case TDB_SUCCESS: return "Success";
 668         case TDB_ERR_CORRUPT: return "Corrupt database";
 669         case TDB_ERR_IO: return "IO Error";
 670         case TDB_ERR_LOCK: return "Locking error";
 671         case TDB_ERR_OOM: return "Out of memory";
 672         case TDB_ERR_EXISTS: return "Record exists";
 673         case TDB_ERR_NESTING: return "Transaction already started";
 674         case TDB_ERR_EINVAL: return "Invalid parameter";
 675         case TDB_ERR_NOEXIST: return "Record does not exist";
 676         case TDB_ERR_RDONLY: return "write not permitted";
 677         }
 678         return "Invalid error code";
 679 }