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

   1 #include "private.h"
   2 #include <ccan/tdb2/tdb2.h>
   3 #include <assert.h>
   4 #include <stdarg.h>
   5
   6 /* The null return. */
   7 struct tdb_data tdb_null = { .dptr = NULL, .dsize = 0 };
   8
   9 /* all contexts, to ensure no double-opens (fcntl locks don't nest!) */
  10 static struct tdb_context *tdbs = NULL;
  11
  12 static bool tdb_already_open(dev_t device, ino_t ino)
  13 {
  14         struct tdb_context *i;
  15
  16         for (i = tdbs; i; i = i->next) {
  17                 if (i->device == device && i->inode == ino) {
  18                         return true;
  19                 }
  20         }
  21
  22         return false;
  23 }
  24
  25 static bool read_all(int fd, void *buf, size_t len)
  26 {
  27         while (len) {
  28                 ssize_t ret;
  29                 ret = read(fd, buf, len);
  30                 if (ret < 0)
  31                         return false;
  32                 if (ret == 0) {
  33                         /* ETOOSHORT? */
  34                         errno = EWOULDBLOCK;
  35                         return false;
  36                 }
  37                 buf = (char *)buf + ret;
  38                 len -= ret;
  39         }
  40         return true;
  41 }
  42
  43 static uint64_t random_number(struct tdb_context *tdb)
  44 {
  45         int fd;
  46         uint64_t ret = 0;
  47         struct timeval now;
  48
  49         fd = open("/dev/urandom", O_RDONLY);
  50         if (fd >= 0) {
  51                 if (read_all(fd, &ret, sizeof(ret))) {
  52                         close(fd);
  53                         return ret;
  54                 }
  55                 close(fd);
  56         }
  57         /* FIXME: Untested!  Based on Wikipedia protocol description! */
  58         fd = open("/dev/egd-pool", O_RDWR);
  59         if (fd >= 0) {
  60                 /* Command is 1, next byte is size we want to read. */
  61                 char cmd[2] = { 1, sizeof(uint64_t) };
  62                 if (write(fd, cmd, sizeof(cmd)) == sizeof(cmd)) {
  63                         char reply[1 + sizeof(uint64_t)];
  64                         int r = read(fd, reply, sizeof(reply));
  65                         if (r > 1) {
  66                                 /* Copy at least some bytes. */
  67                                 memcpy(&ret, reply+1, r - 1);
  68                                 if (reply[0] == sizeof(uint64_t)
  69                                     && r == sizeof(reply)) {
  70                                         close(fd);
  71                                         return ret;
  72                                 }
  73                         }
  74                 }
  75                 close(fd);
  76         }
  77
  78         /* Fallback: pid and time. */
  79         gettimeofday(&now, NULL);
  80         ret = getpid() * 100132289ULL + now.tv_sec * 1000000ULL + now.tv_usec;
  81         tdb_logerr(tdb, TDB_SUCCESS, TDB_LOG_WARNING,
  82                    "tdb_open: random from getpid and time");
  83         return ret;
  84 }
  85
  86 struct new_database {
  87         struct tdb_header hdr;
  88         struct tdb_freetable ftable;
  89 };
  90
  91 /* initialise a new database */
  92 static int tdb_new_database(struct tdb_context *tdb,
  93                             struct tdb_attribute_seed *seed,
  94                             struct tdb_header *hdr)
  95 {
  96         /* We make it up in memory, then write it out if not internal */
  97         struct new_database newdb;
  98         unsigned int magic_len;
  99         ssize_t rlen;
 100
 101         /* Fill in the header */
 102         newdb.hdr.version = TDB_VERSION;
 103         if (seed)
 104                 newdb.hdr.hash_seed = seed->seed;
 105         else
 106                 newdb.hdr.hash_seed = random_number(tdb);
 107         newdb.hdr.hash_test = TDB_HASH_MAGIC;
 108         newdb.hdr.hash_test = tdb->khash(&newdb.hdr.hash_test,
 109                                          sizeof(newdb.hdr.hash_test),
 110                                          newdb.hdr.hash_seed,
 111                                          tdb->hash_priv);
 112         newdb.hdr.recovery = 0;
 113         memset(newdb.hdr.reserved, 0, sizeof(newdb.hdr.reserved));
 114         /* Initial hashes are empty. */
 115         memset(newdb.hdr.hashtable, 0, sizeof(newdb.hdr.hashtable));
 116
 117         /* Free is empty. */
 118         newdb.hdr.free_table = offsetof(struct new_database, ftable);
 119         memset(&newdb.ftable, 0, sizeof(newdb.ftable));
 120         set_header(NULL, &newdb.ftable.hdr, TDB_FTABLE_MAGIC, 0,
 121                    sizeof(newdb.ftable) - sizeof(newdb.ftable.hdr),
 122                    sizeof(newdb.ftable) - sizeof(newdb.ftable.hdr), 0);
 123
 124         /* Magic food */
 125         memset(newdb.hdr.magic_food, 0, sizeof(newdb.hdr.magic_food));
 126         strcpy(newdb.hdr.magic_food, TDB_MAGIC_FOOD);
 127
 128         /* This creates an endian-converted database, as if read from disk */
 129         magic_len = sizeof(newdb.hdr.magic_food);
 130         tdb_convert(tdb,
 131                     (char *)&newdb.hdr + magic_len, sizeof(newdb) - magic_len);
 132
 133         *hdr = newdb.hdr;
 134
 135         if (tdb->flags & TDB_INTERNAL) {
 136                 tdb->map_size = sizeof(newdb);
 137                 tdb->map_ptr = malloc(tdb->map_size);
 138                 if (!tdb->map_ptr) {
 139                         tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
 140                                    "tdb_new_database: failed to allocate");
 141                         return -1;
 142                 }
 143                 memcpy(tdb->map_ptr, &newdb, tdb->map_size);
 144                 return 0;
 145         }
 146         if (lseek(tdb->fd, 0, SEEK_SET) == -1)
 147                 return -1;
 148
 149         if (ftruncate(tdb->fd, 0) == -1)
 150                 return -1;
 151
 152         rlen = write(tdb->fd, &newdb, sizeof(newdb));
 153         if (rlen != sizeof(newdb)) {
 154                 if (rlen >= 0)
 155                         errno = ENOSPC;
 156                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 157                            "tdb_new_database: %zi writing header: %s",
 158                            rlen, strerror(errno));
 159                 return -1;
 160         }
 161         return 0;
 162 }
 163
 164 struct tdb_context *tdb_open(const char *name, int tdb_flags,
 165                              int open_flags, mode_t mode,
 166                              union tdb_attribute *attr)
 167 {
 168         struct tdb_context *tdb;
 169         struct stat st;
 170         int saved_errno = 0;
 171         uint64_t hash_test;
 172         unsigned v;
 173         ssize_t rlen;
 174         struct tdb_header hdr;
 175         struct tdb_attribute_seed *seed = NULL;
 176
 177         tdb = malloc(sizeof(*tdb));
 178         if (!tdb) {
 179                 /* Can't log this */
 180                 errno = ENOMEM;
 181                 return NULL;
 182         }
 183         tdb->name = NULL;
 184         tdb->map_ptr = NULL;
 185         tdb->direct_access = 0;
 186         tdb->fd = -1;
 187         tdb->map_size = sizeof(struct tdb_header);
 188         tdb->ecode = TDB_SUCCESS;
 189         tdb->flags = tdb_flags;
 190         tdb->logfn = NULL;
 191         tdb->transaction = NULL;
 192         tdb->stats = NULL;
 193         tdb->access = NULL;
 194         tdb_hash_init(tdb);
 195         tdb_io_init(tdb);
 196         tdb_lock_init(tdb);
 197
 198         while (attr) {
 199                 switch (attr->base.attr) {
 200                 case TDB_ATTRIBUTE_LOG:
 201                         tdb->logfn = attr->log.log_fn;
 202                         tdb->log_private = attr->log.log_private;
 203                         break;
 204                 case TDB_ATTRIBUTE_HASH:
 205                         tdb->khash = attr->hash.hash_fn;
 206                         tdb->hash_priv = attr->hash.hash_private;
 207                         break;
 208                 case TDB_ATTRIBUTE_SEED:
 209                         seed = &attr->seed;
 210                         break;
 211                 case TDB_ATTRIBUTE_STATS:
 212                         tdb->stats = &attr->stats;
 213                         /* They have stats we don't know about?  Tell them. */
 214                         if (tdb->stats->size > sizeof(attr->stats))
 215                                 tdb->stats->size = sizeof(attr->stats);
 216                         break;
 217                 default:
 218                         tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
 219                                    "tdb_open: unknown attribute type %u",
 220                                    attr->base.attr);
 221                         goto fail;
 222                 }
 223                 attr = attr->base.next;
 224         }
 225
 226         if ((open_flags & O_ACCMODE) == O_WRONLY) {
 227                 tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
 228                            "tdb_open: can't open tdb %s write-only", name);
 229                 goto fail;
 230         }
 231
 232         if ((open_flags & O_ACCMODE) == O_RDONLY) {
 233                 tdb->read_only = true;
 234                 /* read only databases don't do locking */
 235                 tdb->flags |= TDB_NOLOCK;
 236                 tdb->mmap_flags = PROT_READ;
 237         } else {
 238                 tdb->read_only = false;
 239                 tdb->mmap_flags = PROT_READ | PROT_WRITE;
 240         }
 241
 242         /* internal databases don't need any of the rest. */
 243         if (tdb->flags & TDB_INTERNAL) {
 244                 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
 245                 if (tdb_new_database(tdb, seed, &hdr) != 0) {
 246                         goto fail;
 247                 }
 248                 tdb_convert(tdb, &hdr.hash_seed, sizeof(hdr.hash_seed));
 249                 tdb->hash_seed = hdr.hash_seed;
 250                 tdb_ftable_init(tdb);
 251                 return tdb;
 252         }
 253
 254         if ((tdb->fd = open(name, open_flags, mode)) == -1) {
 255                 /* errno set by open(2) */
 256                 saved_errno = errno;
 257                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 258                            "tdb_open: could not open file %s: %s",
 259                            name, strerror(errno));
 260                 goto fail;
 261         }
 262
 263         /* on exec, don't inherit the fd */
 264         v = fcntl(tdb->fd, F_GETFD, 0);
 265         fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);
 266
 267         /* ensure there is only one process initialising at once */
 268         if (tdb_lock_open(tdb, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK) == -1) {
 269                 /* errno set by tdb_brlock */
 270                 saved_errno = errno;
 271                 goto fail;
 272         }
 273
 274         /* If they used O_TRUNC, read will return 0. */
 275         rlen = read(tdb->fd, &hdr, sizeof(hdr));
 276         if (rlen == 0 && (open_flags & O_CREAT)) {
 277                 if (tdb_new_database(tdb, seed, &hdr) == -1) {
 278                         goto fail;
 279                 }
 280         } else if (rlen < 0) {
 281                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 282                            "tdb_open: error %s reading %s",
 283                            strerror(errno), name);
 284                 goto fail;
 285         } else if (rlen < sizeof(hdr)
 286                    || strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0) {
 287                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 288                            "tdb_open: %s is not a tdb file", name);
 289                 goto fail;
 290         }
 291
 292         if (hdr.version != TDB_VERSION) {
 293                 if (hdr.version == bswap_64(TDB_VERSION))
 294                         tdb->flags |= TDB_CONVERT;
 295                 else {
 296                         /* wrong version */
 297                         tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 298                                    "tdb_open: %s is unknown version 0x%llx",
 299                                    name, (long long)hdr.version);
 300                         goto fail;
 301                 }
 302         }
 303
 304         tdb_convert(tdb, &hdr, sizeof(hdr));
 305         tdb->hash_seed = hdr.hash_seed;
 306         hash_test = TDB_HASH_MAGIC;
 307         hash_test = tdb_hash(tdb, &hash_test, sizeof(hash_test));
 308         if (hdr.hash_test != hash_test) {
 309                 /* wrong hash variant */
 310                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 311                            "tdb_open: %s uses a different hash function",
 312                            name);
 313                 goto fail;
 314         }
 315
 316         if (fstat(tdb->fd, &st) == -1) {
 317                 saved_errno = errno;
 318                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 319                            "tdb_open: could not stat open %s: %s",
 320                            name, strerror(errno));
 321                 goto fail;
 322         }
 323
 324         /* Is it already in the open list?  If so, fail. */
 325         if (tdb_already_open(st.st_dev, st.st_ino)) {
 326                 /* FIXME */
 327                 tdb_logerr(tdb, TDB_ERR_NESTING, TDB_LOG_USE_ERROR,
 328                            "tdb_open: %s (%d,%d) is already open in this"
 329                            " process",
 330                            name, (int)st.st_dev, (int)st.st_ino);
 331                 goto fail;
 332         }
 333
 334         tdb->name = strdup(name);
 335         if (!tdb->name) {
 336                 tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
 337                            "tdb_open: failed to allocate name");
 338                 goto fail;
 339         }
 340
 341         tdb->device = st.st_dev;
 342         tdb->inode = st.st_ino;
 343         tdb_unlock_open(tdb);
 344
 345         /* This make sure we have current map_size and mmap. */
 346         tdb->methods->oob(tdb, tdb->map_size + 1, true);
 347
 348         /* Now it's fully formed, recover if necessary. */
 349         if (tdb_needs_recovery(tdb) && tdb_lock_and_recover(tdb) == -1) {
 350                 goto fail;
 351         }
 352
 353         if (tdb_ftable_init(tdb) == -1)
 354                 goto fail;
 355
 356         tdb->next = tdbs;
 357         tdbs = tdb;
 358         return tdb;
 359
 360  fail:
 361         /* Map ecode to some logical errno. */
 362         if (!saved_errno) {
 363                 switch (tdb->ecode) {
 364                 case TDB_ERR_CORRUPT:
 365                 case TDB_ERR_IO:
 366                         saved_errno = EIO;
 367                         break;
 368                 case TDB_ERR_LOCK:
 369                         saved_errno = EWOULDBLOCK;
 370                         break;
 371                 case TDB_ERR_OOM:
 372                         saved_errno = ENOMEM;
 373                         break;
 374                 case TDB_ERR_EINVAL:
 375                         saved_errno = EINVAL;
 376                         break;
 377                 case TDB_ERR_NESTING:
 378                         saved_errno = EBUSY;
 379                         break;
 380                 default:
 381                         saved_errno = EINVAL;
 382                         break;
 383                 }
 384         }
 385
 386 #ifdef TDB_TRACE
 387         close(tdb->tracefd);
 388 #endif
 389         if (tdb->map_ptr) {
 390                 if (tdb->flags & TDB_INTERNAL) {
 391                         free(tdb->map_ptr);
 392                 } else
 393                         tdb_munmap(tdb);
 394         }
 395         free(tdb->lockrecs);
 396         free((char *)tdb->name);
 397         if (tdb->fd != -1)
 398                 if (close(tdb->fd) != 0)
 399                         tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 400                                    "tdb_open: failed to close tdb->fd"
 401                                    " on error: %s", strerror(errno));
 402         free(tdb);
 403         errno = saved_errno;
 404         return NULL;
 405 }
 406
 407 static int update_rec_hdr(struct tdb_context *tdb,
 408                           tdb_off_t off,
 409                           tdb_len_t keylen,
 410                           tdb_len_t datalen,
 411                           struct tdb_used_record *rec,
 412                           uint64_t h)
 413 {
 414         uint64_t dataroom = rec_data_length(rec) + rec_extra_padding(rec);
 415
 416         if (set_header(tdb, rec, TDB_USED_MAGIC, keylen, datalen,
 417                        keylen + dataroom, h))
 418                 return -1;
 419
 420         return tdb_write_convert(tdb, off, rec, sizeof(*rec));
 421 }
 422
 423 /* Returns -1 on error, 0 on OK */
 424 static int replace_data(struct tdb_context *tdb,
 425                         struct hash_info *h,
 426                         struct tdb_data key, struct tdb_data dbuf,
 427                         tdb_off_t old_off, tdb_len_t old_room,
 428                         bool growing)
 429 {
 430         tdb_off_t new_off;
 431
 432         /* Allocate a new record. */
 433         new_off = alloc(tdb, key.dsize, dbuf.dsize, h->h, TDB_USED_MAGIC,
 434                         growing);
 435         if (unlikely(new_off == TDB_OFF_ERR))
 436                 return -1;
 437
 438         /* We didn't like the existing one: remove it. */
 439         if (old_off) {
 440                 add_stat(tdb, frees, 1);
 441                 add_free_record(tdb, old_off,
 442                                 sizeof(struct tdb_used_record)
 443                                 + key.dsize + old_room);
 444                 if (replace_in_hash(tdb, h, new_off) == -1)
 445                         return -1;
 446         } else {
 447                 if (add_to_hash(tdb, h, new_off) == -1)
 448                         return -1;
 449         }
 450
 451         new_off += sizeof(struct tdb_used_record);
 452         if (tdb->methods->twrite(tdb, new_off, key.dptr, key.dsize) == -1)
 453                 return -1;
 454
 455         new_off += key.dsize;
 456         if (tdb->methods->twrite(tdb, new_off, dbuf.dptr, dbuf.dsize) == -1)
 457                 return -1;
 458
 459         /* FIXME: tdb_increment_seqnum(tdb); */
 460         return 0;
 461 }
 462
 463 int tdb_store(struct tdb_context *tdb,
 464               struct tdb_data key, struct tdb_data dbuf, int flag)
 465 {
 466         struct hash_info h;
 467         tdb_off_t off;
 468         tdb_len_t old_room = 0;
 469         struct tdb_used_record rec;
 470         int ret;
 471
 472         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 473         if (unlikely(off == TDB_OFF_ERR))
 474                 return -1;
 475
 476         /* Now we have lock on this hash bucket. */
 477         if (flag == TDB_INSERT) {
 478                 if (off) {
 479                         tdb->ecode = TDB_ERR_EXISTS;
 480                         goto fail;
 481                 }
 482         } else {
 483                 if (off) {
 484                         old_room = rec_data_length(&rec)
 485                                 + rec_extra_padding(&rec);
 486                         if (old_room >= dbuf.dsize) {
 487                                 /* Can modify in-place.  Easy! */
 488                                 if (update_rec_hdr(tdb, off,
 489                                                    key.dsize, dbuf.dsize,
 490                                                    &rec, h.h))
 491                                         goto fail;
 492                                 if (tdb->methods->twrite(tdb, off + sizeof(rec)
 493                                                          + key.dsize,
 494                                                          dbuf.dptr, dbuf.dsize))
 495                                         goto fail;
 496                                 tdb_unlock_hashes(tdb, h.hlock_start,
 497                                                   h.hlock_range, F_WRLCK);
 498                                 return 0;
 499                         }
 500                 } else {
 501                         if (flag == TDB_MODIFY) {
 502                                 /* if the record doesn't exist and we
 503                                    are in TDB_MODIFY mode then we should fail
 504                                    the store */
 505                                 tdb->ecode = TDB_ERR_NOEXIST;
 506                                 goto fail;
 507                         }
 508                 }
 509         }
 510
 511         /* If we didn't use the old record, this implies we're growing. */
 512         ret = replace_data(tdb, &h, key, dbuf, off, old_room, off != 0);
 513         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 514         return ret;
 515
 516 fail:
 517         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 518         return -1;
 519 }
 520
 521 int tdb_append(struct tdb_context *tdb,
 522                struct tdb_data key, struct tdb_data dbuf)
 523 {
 524         struct hash_info h;
 525         tdb_off_t off;
 526         struct tdb_used_record rec;
 527         tdb_len_t old_room = 0, old_dlen;
 528         unsigned char *newdata;
 529         struct tdb_data new_dbuf;
 530         int ret;
 531
 532         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 533         if (unlikely(off == TDB_OFF_ERR))
 534                 return -1;
 535
 536         if (off) {
 537                 old_dlen = rec_data_length(&rec);
 538                 old_room = old_dlen + rec_extra_padding(&rec);
 539
 540                 /* Fast path: can append in place. */
 541                 if (rec_extra_padding(&rec) >= dbuf.dsize) {
 542                         if (update_rec_hdr(tdb, off, key.dsize,
 543                                            old_dlen + dbuf.dsize, &rec, h.h))
 544                                 goto fail;
 545
 546                         off += sizeof(rec) + key.dsize + old_dlen;
 547                         if (tdb->methods->twrite(tdb, off, dbuf.dptr,
 548                                                  dbuf.dsize) == -1)
 549                                 goto fail;
 550
 551                         /* FIXME: tdb_increment_seqnum(tdb); */
 552                         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range,
 553                                           F_WRLCK);
 554                         return 0;
 555                 }
 556
 557                 /* Slow path. */
 558                 newdata = malloc(key.dsize + old_dlen + dbuf.dsize);
 559                 if (!newdata) {
 560                         tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
 561                                    "tdb_append: failed to allocate %zu bytes",
 562                                    (size_t)(key.dsize+old_dlen+dbuf.dsize));
 563                         goto fail;
 564                 }
 565                 if (tdb->methods->tread(tdb, off + sizeof(rec) + key.dsize,
 566                                         newdata, old_dlen) != 0) {
 567                         free(newdata);
 568                         goto fail;
 569                 }
 570                 memcpy(newdata + old_dlen, dbuf.dptr, dbuf.dsize);
 571                 new_dbuf.dptr = newdata;
 572                 new_dbuf.dsize = old_dlen + dbuf.dsize;
 573         } else {
 574                 newdata = NULL;
 575                 new_dbuf = dbuf;
 576         }
 577
 578         /* If they're using tdb_append(), it implies they're growing record. */
 579         ret = replace_data(tdb, &h, key, new_dbuf, off, old_room, true);
 580         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 581         free(newdata);
 582
 583         return ret;
 584
 585 fail:
 586         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 587         return -1;
 588 }
 589
 590 struct tdb_data tdb_fetch(struct tdb_context *tdb, struct tdb_data key)
 591 {
 592         tdb_off_t off;
 593         struct tdb_used_record rec;
 594         struct hash_info h;
 595         struct tdb_data ret;
 596
 597         off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
 598         if (unlikely(off == TDB_OFF_ERR))
 599                 return tdb_null;
 600
 601         if (!off) {
 602                 tdb->ecode = TDB_ERR_NOEXIST;
 603                 ret = tdb_null;
 604         } else {
 605                 ret.dsize = rec_data_length(&rec);
 606                 ret.dptr = tdb_alloc_read(tdb, off + sizeof(rec) + key.dsize,
 607                                           ret.dsize);
 608         }
 609
 610         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
 611         return ret;
 612 }
 613
 614 int tdb_delete(struct tdb_context *tdb, struct tdb_data key)
 615 {
 616         tdb_off_t off;
 617         struct tdb_used_record rec;
 618         struct hash_info h;
 619
 620         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 621         if (unlikely(off == TDB_OFF_ERR))
 622                 return -1;
 623
 624         if (!off) {
 625                 tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 626                 tdb->ecode = TDB_ERR_NOEXIST;
 627                 return -1;
 628         }
 629
 630         if (delete_from_hash(tdb, &h) == -1)
 631                 goto unlock_err;
 632
 633         /* Free the deleted entry. */
 634         add_stat(tdb, frees, 1);
 635         if (add_free_record(tdb, off,
 636                             sizeof(struct tdb_used_record)
 637                             + rec_key_length(&rec)
 638                             + rec_data_length(&rec)
 639                             + rec_extra_padding(&rec)) != 0)
 640                 goto unlock_err;
 641
 642         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 643         return 0;
 644
 645 unlock_err:
 646         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 647         return -1;
 648 }
 649
 650 int tdb_close(struct tdb_context *tdb)
 651 {
 652         struct tdb_context **i;
 653         int ret = 0;
 654
 655         tdb_trace(tdb, "tdb_close");
 656
 657         if (tdb->transaction) {
 658                 tdb_transaction_cancel(tdb);
 659         }
 660
 661         if (tdb->map_ptr) {
 662                 if (tdb->flags & TDB_INTERNAL)
 663                         free(tdb->map_ptr);
 664                 else
 665                         tdb_munmap(tdb);
 666         }
 667         free((char *)tdb->name);
 668         if (tdb->fd != -1) {
 669                 ret = close(tdb->fd);
 670                 tdb->fd = -1;
 671         }
 672         free(tdb->lockrecs);
 673
 674         /* Remove from contexts list */
 675         for (i = &tdbs; *i; i = &(*i)->next) {
 676                 if (*i == tdb) {
 677                         *i = tdb->next;
 678                         break;
 679                 }
 680         }
 681
 682 #ifdef TDB_TRACE
 683         close(tdb->tracefd);
 684 #endif
 685         free(tdb);
 686
 687         return ret;
 688 }
 689
 690 enum TDB_ERROR tdb_error(const struct tdb_context *tdb)
 691 {
 692         return tdb->ecode;
 693 }
 694
 695 const char *tdb_errorstr(const struct tdb_context *tdb)
 696 {
 697         /* Gcc warns if you miss a case in the switch, so use that. */
 698         switch (tdb->ecode) {
 699         case TDB_SUCCESS: return "Success";
 700         case TDB_ERR_CORRUPT: return "Corrupt database";
 701         case TDB_ERR_IO: return "IO Error";
 702         case TDB_ERR_LOCK: return "Locking error";
 703         case TDB_ERR_OOM: return "Out of memory";
 704         case TDB_ERR_EXISTS: return "Record exists";
 705         case TDB_ERR_NESTING: return "Transaction already started";
 706         case TDB_ERR_EINVAL: return "Invalid parameter";
 707         case TDB_ERR_NOEXIST: return "Record does not exist";
 708         case TDB_ERR_RDONLY: return "write not permitted";
 709         }
 710         return "Invalid error code";
 711 }
 712
 713 void COLD tdb_logerr(struct tdb_context *tdb,
 714                      enum TDB_ERROR ecode,
 715                      enum tdb_log_level level,
 716                      const char *fmt, ...)
 717 {
 718         char *message;
 719         va_list ap;
 720         size_t len;
 721         /* tdb_open paths care about errno, so save it. */
 722         int saved_errno = errno;
 723
 724         tdb->ecode = ecode;
 725
 726         if (!tdb->logfn)
 727                 return;
 728
 729         /* FIXME: Doesn't assume asprintf. */
 730         va_start(ap, fmt);
 731         len = vsnprintf(NULL, 0, fmt, ap);
 732         va_end(ap);
 733
 734         message = malloc(len + 1);
 735         if (!message) {
 736                 tdb->logfn(tdb, TDB_LOG_ERROR, tdb->log_private,
 737                            "out of memory formatting message:");
 738                 tdb->logfn(tdb, level, tdb->log_private, fmt);
 739                 return;
 740         }
 741         va_start(ap, fmt);
 742         len = vsprintf(message, fmt, ap);
 743         va_end(ap);
 744         tdb->logfn(tdb, level, tdb->log_private, message);
 745         free(message);
 746         errno = saved_errno;
 747 }