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 enum TDB_ERROR 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         enum TDB_ERROR ecode;
 101
 102         /* Fill in the header */
 103         newdb.hdr.version = TDB_VERSION;
 104         if (seed)
 105                 newdb.hdr.hash_seed = seed->seed;
 106         else
 107                 newdb.hdr.hash_seed = random_number(tdb);
 108         newdb.hdr.hash_test = TDB_HASH_MAGIC;
 109         newdb.hdr.hash_test = tdb->khash(&newdb.hdr.hash_test,
 110                                          sizeof(newdb.hdr.hash_test),
 111                                          newdb.hdr.hash_seed,
 112                                          tdb->hash_priv);
 113         newdb.hdr.recovery = 0;
 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 empty. */
 119         newdb.hdr.free_table = offsetof(struct new_database, ftable);
 120         memset(&newdb.ftable, 0, sizeof(newdb.ftable));
 121         ecode = set_header(NULL, &newdb.ftable.hdr, TDB_FTABLE_MAGIC, 0,
 122                            sizeof(newdb.ftable) - sizeof(newdb.ftable.hdr),
 123                            sizeof(newdb.ftable) - sizeof(newdb.ftable.hdr),
 124                            0);
 125         if (ecode != TDB_SUCCESS) {
 126                 return ecode;
 127         }
 128
 129         /* Magic food */
 130         memset(newdb.hdr.magic_food, 0, sizeof(newdb.hdr.magic_food));
 131         strcpy(newdb.hdr.magic_food, TDB_MAGIC_FOOD);
 132
 133         /* This creates an endian-converted database, as if read from disk */
 134         magic_len = sizeof(newdb.hdr.magic_food);
 135         tdb_convert(tdb,
 136                     (char *)&newdb.hdr + magic_len, sizeof(newdb) - magic_len);
 137
 138         *hdr = newdb.hdr;
 139
 140         if (tdb->flags & TDB_INTERNAL) {
 141                 tdb->map_size = sizeof(newdb);
 142                 tdb->map_ptr = malloc(tdb->map_size);
 143                 if (!tdb->map_ptr) {
 144                         return tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
 145                                           "tdb_new_database:"
 146                                           " failed to allocate");
 147                 }
 148                 memcpy(tdb->map_ptr, &newdb, tdb->map_size);
 149                 return TDB_SUCCESS;
 150         }
 151         if (lseek(tdb->fd, 0, SEEK_SET) == -1) {
 152                 return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 153                                   "tdb_new_database:"
 154                                   " failed to seek: %s", strerror(errno));
 155         }
 156
 157         if (ftruncate(tdb->fd, 0) == -1) {
 158                 return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 159                                   "tdb_new_database:"
 160                                   " failed to truncate: %s", strerror(errno));
 161         }
 162
 163         rlen = write(tdb->fd, &newdb, sizeof(newdb));
 164         if (rlen != sizeof(newdb)) {
 165                 if (rlen >= 0)
 166                         errno = ENOSPC;
 167                 return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 168                                   "tdb_new_database: %zi writing header: %s",
 169                                   rlen, strerror(errno));
 170         }
 171         return TDB_SUCCESS;
 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 saved_errno = 0;
 181         uint64_t hash_test;
 182         unsigned v;
 183         ssize_t rlen;
 184         struct tdb_header hdr;
 185         struct tdb_attribute_seed *seed = NULL;
 186         tdb_bool_err berr;
 187         enum TDB_ERROR ecode;
 188
 189         tdb = malloc(sizeof(*tdb));
 190         if (!tdb) {
 191                 /* Can't log this */
 192                 errno = ENOMEM;
 193                 return NULL;
 194         }
 195         tdb->name = NULL;
 196         tdb->map_ptr = NULL;
 197         tdb->direct_access = 0;
 198         tdb->fd = -1;
 199         tdb->map_size = sizeof(struct tdb_header);
 200         tdb->ecode = TDB_SUCCESS;
 201         tdb->flags = tdb_flags;
 202         tdb->logfn = NULL;
 203         tdb->transaction = NULL;
 204         tdb->stats = NULL;
 205         tdb->access = NULL;
 206         tdb_hash_init(tdb);
 207         tdb_io_init(tdb);
 208         tdb_lock_init(tdb);
 209
 210         while (attr) {
 211                 switch (attr->base.attr) {
 212                 case TDB_ATTRIBUTE_LOG:
 213                         tdb->logfn = attr->log.log_fn;
 214                         tdb->log_private = attr->log.log_private;
 215                         break;
 216                 case TDB_ATTRIBUTE_HASH:
 217                         tdb->khash = attr->hash.hash_fn;
 218                         tdb->hash_priv = attr->hash.hash_private;
 219                         break;
 220                 case TDB_ATTRIBUTE_SEED:
 221                         seed = &attr->seed;
 222                         break;
 223                 case TDB_ATTRIBUTE_STATS:
 224                         tdb->stats = &attr->stats;
 225                         /* They have stats we don't know about?  Tell them. */
 226                         if (tdb->stats->size > sizeof(attr->stats))
 227                                 tdb->stats->size = sizeof(attr->stats);
 228                         break;
 229                 default:
 230                         tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
 231                                    "tdb_open: unknown attribute type %u",
 232                                    attr->base.attr);
 233                         goto fail;
 234                 }
 235                 attr = attr->base.next;
 236         }
 237
 238         if ((open_flags & O_ACCMODE) == O_WRONLY) {
 239                 tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
 240                            "tdb_open: can't open tdb %s write-only", name);
 241                 goto fail;
 242         }
 243
 244         if ((open_flags & O_ACCMODE) == O_RDONLY) {
 245                 tdb->read_only = true;
 246                 /* read only databases don't do locking */
 247                 tdb->flags |= TDB_NOLOCK;
 248                 tdb->mmap_flags = PROT_READ;
 249         } else {
 250                 tdb->read_only = false;
 251                 tdb->mmap_flags = PROT_READ | PROT_WRITE;
 252         }
 253
 254         /* internal databases don't need any of the rest. */
 255         if (tdb->flags & TDB_INTERNAL) {
 256                 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
 257                 if (tdb_new_database(tdb, seed, &hdr) != 0) {
 258                         goto fail;
 259                 }
 260                 tdb_convert(tdb, &hdr.hash_seed, sizeof(hdr.hash_seed));
 261                 tdb->hash_seed = hdr.hash_seed;
 262                 tdb_ftable_init(tdb);
 263                 return tdb;
 264         }
 265
 266         if ((tdb->fd = open(name, open_flags, mode)) == -1) {
 267                 /* errno set by open(2) */
 268                 saved_errno = errno;
 269                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 270                            "tdb_open: could not open file %s: %s",
 271                            name, strerror(errno));
 272                 goto fail;
 273         }
 274
 275         /* on exec, don't inherit the fd */
 276         v = fcntl(tdb->fd, F_GETFD, 0);
 277         fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);
 278
 279         /* ensure there is only one process initialising at once */
 280         tdb->ecode = tdb_lock_open(tdb, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK);
 281         if (tdb->ecode != TDB_SUCCESS) {
 282                 goto fail;
 283         }
 284
 285         /* If they used O_TRUNC, read will return 0. */
 286         rlen = read(tdb->fd, &hdr, sizeof(hdr));
 287         if (rlen == 0 && (open_flags & O_CREAT)) {
 288                 if (tdb_new_database(tdb, seed, &hdr) == -1) {
 289                         goto fail;
 290                 }
 291         } else if (rlen < 0) {
 292                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 293                            "tdb_open: error %s reading %s",
 294                            strerror(errno), name);
 295                 goto fail;
 296         } else if (rlen < sizeof(hdr)
 297                    || strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0) {
 298                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 299                            "tdb_open: %s is not a tdb file", name);
 300                 goto fail;
 301         }
 302
 303         if (hdr.version != TDB_VERSION) {
 304                 if (hdr.version == bswap_64(TDB_VERSION))
 305                         tdb->flags |= TDB_CONVERT;
 306                 else {
 307                         /* wrong version */
 308                         tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 309                                    "tdb_open: %s is unknown version 0x%llx",
 310                                    name, (long long)hdr.version);
 311                         goto fail;
 312                 }
 313         }
 314
 315         tdb_convert(tdb, &hdr, sizeof(hdr));
 316         tdb->hash_seed = hdr.hash_seed;
 317         hash_test = TDB_HASH_MAGIC;
 318         hash_test = tdb_hash(tdb, &hash_test, sizeof(hash_test));
 319         if (hdr.hash_test != hash_test) {
 320                 /* wrong hash variant */
 321                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 322                            "tdb_open: %s uses a different hash function",
 323                            name);
 324                 goto fail;
 325         }
 326
 327         if (fstat(tdb->fd, &st) == -1) {
 328                 saved_errno = errno;
 329                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 330                            "tdb_open: could not stat open %s: %s",
 331                            name, strerror(errno));
 332                 goto fail;
 333         }
 334
 335         /* Is it already in the open list?  If so, fail. */
 336         if (tdb_already_open(st.st_dev, st.st_ino)) {
 337                 /* FIXME */
 338                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_USE_ERROR,
 339                            "tdb_open: %s (%d,%d) is already open in this"
 340                            " process",
 341                            name, (int)st.st_dev, (int)st.st_ino);
 342                 goto fail;
 343         }
 344
 345         tdb->name = strdup(name);
 346         if (!tdb->name) {
 347                 tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
 348                            "tdb_open: failed to allocate name");
 349                 goto fail;
 350         }
 351
 352         tdb->device = st.st_dev;
 353         tdb->inode = st.st_ino;
 354         tdb_unlock_open(tdb);
 355
 356         /* This make sure we have current map_size and mmap. */
 357         tdb->methods->oob(tdb, tdb->map_size + 1, true);
 358
 359         /* Now it's fully formed, recover if necessary. */
 360         berr = tdb_needs_recovery(tdb);
 361         if (unlikely(berr != false)) {
 362                 if (berr < 0) {
 363                         ecode = berr;
 364                         goto fail;
 365                 }
 366                 ecode = tdb_lock_and_recover(tdb);
 367                 if (ecode != TDB_SUCCESS) {
 368                         tdb->ecode = ecode;
 369                         goto fail;
 370                 }
 371         }
 372
 373         tdb->ecode = tdb_ftable_init(tdb);
 374         if (tdb->ecode != TDB_SUCCESS) {
 375                 goto fail;
 376         }
 377
 378         tdb->next = tdbs;
 379         tdbs = tdb;
 380         return tdb;
 381
 382  fail:
 383         /* Map ecode to some logical errno. */
 384         if (!saved_errno) {
 385                 switch (tdb->ecode) {
 386                 case TDB_ERR_CORRUPT:
 387                 case TDB_ERR_IO:
 388                         saved_errno = EIO;
 389                         break;
 390                 case TDB_ERR_LOCK:
 391                         saved_errno = EWOULDBLOCK;
 392                         break;
 393                 case TDB_ERR_OOM:
 394                         saved_errno = ENOMEM;
 395                         break;
 396                 case TDB_ERR_EINVAL:
 397                         saved_errno = EINVAL;
 398                         break;
 399                 default:
 400                         saved_errno = EINVAL;
 401                         break;
 402                 }
 403         }
 404
 405 #ifdef TDB_TRACE
 406         close(tdb->tracefd);
 407 #endif
 408         if (tdb->map_ptr) {
 409                 if (tdb->flags & TDB_INTERNAL) {
 410                         free(tdb->map_ptr);
 411                 } else
 412                         tdb_munmap(tdb);
 413         }
 414         free(tdb->lockrecs);
 415         free((char *)tdb->name);
 416         if (tdb->fd != -1)
 417                 if (close(tdb->fd) != 0)
 418                         tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 419                                    "tdb_open: failed to close tdb->fd"
 420                                    " on error: %s", strerror(errno));
 421         free(tdb);
 422         errno = saved_errno;
 423         return NULL;
 424 }
 425
 426 static enum TDB_ERROR update_rec_hdr(struct tdb_context *tdb,
 427                                      tdb_off_t off,
 428                                      tdb_len_t keylen,
 429                                      tdb_len_t datalen,
 430                                      struct tdb_used_record *rec,
 431                                      uint64_t h)
 432 {
 433         uint64_t dataroom = rec_data_length(rec) + rec_extra_padding(rec);
 434         enum TDB_ERROR ecode;
 435
 436         ecode = set_header(tdb, rec, TDB_USED_MAGIC, keylen, datalen,
 437                            keylen + dataroom, h);
 438         if (ecode == TDB_SUCCESS) {
 439                 ecode = tdb_write_convert(tdb, off, rec, sizeof(*rec));
 440         }
 441         return ecode;
 442 }
 443
 444 static enum TDB_ERROR replace_data(struct tdb_context *tdb,
 445                                    struct hash_info *h,
 446                                    struct tdb_data key, struct tdb_data dbuf,
 447                                    tdb_off_t old_off, tdb_len_t old_room,
 448                                    bool growing)
 449 {
 450         tdb_off_t new_off;
 451         enum TDB_ERROR ecode;
 452
 453         /* Allocate a new record. */
 454         new_off = alloc(tdb, key.dsize, dbuf.dsize, h->h, TDB_USED_MAGIC,
 455                         growing);
 456         if (TDB_OFF_IS_ERR(new_off)) {
 457                 return new_off;
 458         }
 459
 460         /* We didn't like the existing one: remove it. */
 461         if (old_off) {
 462                 add_stat(tdb, frees, 1);
 463                 ecode = add_free_record(tdb, old_off,
 464                                         sizeof(struct tdb_used_record)
 465                                         + key.dsize + old_room);
 466                 if (ecode == TDB_SUCCESS)
 467                         ecode = replace_in_hash(tdb, h, new_off);
 468         } else {
 469                 ecode = add_to_hash(tdb, h, new_off);
 470         }
 471         if (ecode != TDB_SUCCESS) {
 472                 return ecode;
 473         }
 474
 475         new_off += sizeof(struct tdb_used_record);
 476         ecode = tdb->methods->twrite(tdb, new_off, key.dptr, key.dsize);
 477         if (ecode != TDB_SUCCESS) {
 478                 return ecode;
 479         }
 480
 481         new_off += key.dsize;
 482         ecode = tdb->methods->twrite(tdb, new_off, dbuf.dptr, dbuf.dsize);
 483         if (ecode != TDB_SUCCESS) {
 484                 return ecode;
 485         }
 486
 487         /* FIXME: tdb_increment_seqnum(tdb); */
 488         return TDB_SUCCESS;
 489 }
 490
 491 int tdb_store(struct tdb_context *tdb,
 492               struct tdb_data key, struct tdb_data dbuf, int flag)
 493 {
 494         struct hash_info h;
 495         tdb_off_t off;
 496         tdb_len_t old_room = 0;
 497         struct tdb_used_record rec;
 498         enum TDB_ERROR ecode;
 499
 500         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 501         if (TDB_OFF_IS_ERR(off)) {
 502                 tdb->ecode = off;
 503                 return -1;
 504         }
 505
 506         /* Now we have lock on this hash bucket. */
 507         if (flag == TDB_INSERT) {
 508                 if (off) {
 509                         tdb->ecode = TDB_ERR_EXISTS;
 510                         goto fail;
 511                 }
 512         } else {
 513                 if (off) {
 514                         old_room = rec_data_length(&rec)
 515                                 + rec_extra_padding(&rec);
 516                         if (old_room >= dbuf.dsize) {
 517                                 /* Can modify in-place.  Easy! */
 518                                 ecode = update_rec_hdr(tdb, off,
 519                                                        key.dsize, dbuf.dsize,
 520                                                        &rec, h.h);
 521                                 if (ecode != TDB_SUCCESS) {
 522                                         tdb->ecode = ecode;
 523                                         goto fail;
 524                                 }
 525                                 ecode = tdb->methods->twrite(tdb,
 526                                                              off + sizeof(rec)
 527                                                              + key.dsize,
 528                                                              dbuf.dptr,
 529                                                              dbuf.dsize);
 530                                 if (ecode != TDB_SUCCESS) {
 531                                         tdb->ecode = ecode;
 532                                         goto fail;
 533                                 }
 534                                 tdb_unlock_hashes(tdb, h.hlock_start,
 535                                                   h.hlock_range, F_WRLCK);
 536                                 return 0;
 537                         }
 538                 } else {
 539                         if (flag == TDB_MODIFY) {
 540                                 /* if the record doesn't exist and we
 541                                    are in TDB_MODIFY mode then we should fail
 542                                    the store */
 543                                 tdb->ecode = TDB_ERR_NOEXIST;
 544                                 goto fail;
 545                         }
 546                 }
 547         }
 548
 549         /* If we didn't use the old record, this implies we're growing. */
 550         ecode = replace_data(tdb, &h, key, dbuf, off, old_room, off);
 551         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 552         if (ecode != TDB_SUCCESS) {
 553                 tdb->ecode = ecode;
 554                 return -1;
 555         }
 556         return 0;
 557
 558 fail:
 559         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 560         return -1;
 561 }
 562
 563 int tdb_append(struct tdb_context *tdb,
 564                struct tdb_data key, struct tdb_data dbuf)
 565 {
 566         struct hash_info h;
 567         tdb_off_t off;
 568         struct tdb_used_record rec;
 569         tdb_len_t old_room = 0, old_dlen;
 570         unsigned char *newdata;
 571         struct tdb_data new_dbuf;
 572         enum TDB_ERROR ecode;
 573
 574         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 575         if (TDB_OFF_IS_ERR(off)) {
 576                 tdb->ecode = off;
 577                 return -1;
 578         }
 579
 580         if (off) {
 581                 old_dlen = rec_data_length(&rec);
 582                 old_room = old_dlen + rec_extra_padding(&rec);
 583
 584                 /* Fast path: can append in place. */
 585                 if (rec_extra_padding(&rec) >= dbuf.dsize) {
 586                         ecode = update_rec_hdr(tdb, off, key.dsize,
 587                                                old_dlen + dbuf.dsize, &rec,
 588                                                h.h);
 589                         if (ecode != TDB_SUCCESS) {
 590                                 tdb->ecode = ecode;
 591                                 goto fail;
 592                         }
 593
 594                         off += sizeof(rec) + key.dsize + old_dlen;
 595                         ecode = tdb->methods->twrite(tdb, off, dbuf.dptr,
 596                                                      dbuf.dsize);
 597                         if (ecode != TDB_SUCCESS) {
 598                                 tdb->ecode = ecode;
 599                                 goto fail;
 600                         }
 601
 602                         /* FIXME: tdb_increment_seqnum(tdb); */
 603                         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range,
 604                                           F_WRLCK);
 605                         return 0;
 606                 }
 607
 608                 /* Slow path. */
 609                 newdata = malloc(key.dsize + old_dlen + dbuf.dsize);
 610                 if (!newdata) {
 611                         tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
 612                                    "tdb_append: failed to allocate %zu bytes",
 613                                    (size_t)(key.dsize+old_dlen+dbuf.dsize));
 614                         goto fail;
 615                 }
 616                 ecode = tdb->methods->tread(tdb, off + sizeof(rec) + key.dsize,
 617                                             newdata, old_dlen);
 618                 if (ecode != TDB_SUCCESS) {
 619                         tdb->ecode = ecode;
 620                         free(newdata);
 621                         goto fail;
 622                 }
 623                 memcpy(newdata + old_dlen, dbuf.dptr, dbuf.dsize);
 624                 new_dbuf.dptr = newdata;
 625                 new_dbuf.dsize = old_dlen + dbuf.dsize;
 626         } else {
 627                 newdata = NULL;
 628                 new_dbuf = dbuf;
 629         }
 630
 631         /* If they're using tdb_append(), it implies they're growing record. */
 632         ecode = replace_data(tdb, &h, key, new_dbuf, off, old_room, true);
 633         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 634         free(newdata);
 635
 636         if (ecode != TDB_SUCCESS) {
 637                 tdb->ecode = ecode;
 638                 return -1;
 639         }
 640         return 0;
 641
 642 fail:
 643         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 644         return -1;
 645 }
 646
 647 struct tdb_data tdb_fetch(struct tdb_context *tdb, struct tdb_data key)
 648 {
 649         tdb_off_t off;
 650         struct tdb_used_record rec;
 651         struct hash_info h;
 652         struct tdb_data ret;
 653
 654         off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
 655         if (TDB_OFF_IS_ERR(off)) {
 656                 tdb->ecode = off;
 657                 return tdb_null;
 658         }
 659
 660         if (!off) {
 661                 tdb->ecode = TDB_ERR_NOEXIST;
 662                 ret = tdb_null;
 663         } else {
 664                 ret.dsize = rec_data_length(&rec);
 665                 ret.dptr = tdb_alloc_read(tdb, off + sizeof(rec) + key.dsize,
 666                                           ret.dsize);
 667                 if (TDB_PTR_IS_ERR(ret.dptr)) {
 668                         tdb->ecode = TDB_PTR_ERR(ret.dptr);
 669                         ret = tdb_null;
 670                 }
 671         }
 672
 673         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
 674         return ret;
 675 }
 676
 677 int tdb_delete(struct tdb_context *tdb, struct tdb_data key)
 678 {
 679         tdb_off_t off;
 680         struct tdb_used_record rec;
 681         struct hash_info h;
 682         enum TDB_ERROR ecode;
 683
 684         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 685         if (TDB_OFF_IS_ERR(off)) {
 686                 tdb->ecode = off;
 687                 return -1;
 688         }
 689
 690         if (!off) {
 691                 tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 692                 tdb->ecode = TDB_ERR_NOEXIST;
 693                 return -1;
 694         }
 695
 696         ecode = delete_from_hash(tdb, &h);
 697         if (ecode != TDB_SUCCESS) {
 698                 tdb->ecode = ecode;
 699                 goto unlock_err;
 700         }
 701
 702         /* Free the deleted entry. */
 703         add_stat(tdb, frees, 1);
 704         ecode = add_free_record(tdb, off,
 705                                 sizeof(struct tdb_used_record)
 706                                 + rec_key_length(&rec)
 707                                 + rec_data_length(&rec)
 708                                 + rec_extra_padding(&rec));
 709         if (ecode != TDB_SUCCESS) {
 710                 tdb->ecode = ecode;
 711                 goto unlock_err;
 712         }
 713
 714         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 715         return 0;
 716
 717 unlock_err:
 718         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 719         return -1;
 720 }
 721
 722 int tdb_close(struct tdb_context *tdb)
 723 {
 724         struct tdb_context **i;
 725         int ret = 0;
 726
 727         tdb_trace(tdb, "tdb_close");
 728
 729         if (tdb->transaction) {
 730                 tdb_transaction_cancel(tdb);
 731         }
 732
 733         if (tdb->map_ptr) {
 734                 if (tdb->flags & TDB_INTERNAL)
 735                         free(tdb->map_ptr);
 736                 else
 737                         tdb_munmap(tdb);
 738         }
 739         free((char *)tdb->name);
 740         if (tdb->fd != -1) {
 741                 ret = close(tdb->fd);
 742                 tdb->fd = -1;
 743         }
 744         free(tdb->lockrecs);
 745
 746         /* Remove from contexts list */
 747         for (i = &tdbs; *i; i = &(*i)->next) {
 748                 if (*i == tdb) {
 749                         *i = tdb->next;
 750                         break;
 751                 }
 752         }
 753
 754 #ifdef TDB_TRACE
 755         close(tdb->tracefd);
 756 #endif
 757         free(tdb);
 758
 759         return ret;
 760 }
 761
 762 enum TDB_ERROR tdb_error(const struct tdb_context *tdb)
 763 {
 764         return tdb->ecode;
 765 }
 766
 767 const char *tdb_errorstr(const struct tdb_context *tdb)
 768 {
 769         /* Gcc warns if you miss a case in the switch, so use that. */
 770         switch (tdb->ecode) {
 771         case TDB_SUCCESS: return "Success";
 772         case TDB_ERR_CORRUPT: return "Corrupt database";
 773         case TDB_ERR_IO: return "IO Error";
 774         case TDB_ERR_LOCK: return "Locking error";
 775         case TDB_ERR_OOM: return "Out of memory";
 776         case TDB_ERR_EXISTS: return "Record exists";
 777         case TDB_ERR_EINVAL: return "Invalid parameter";
 778         case TDB_ERR_NOEXIST: return "Record does not exist";
 779         case TDB_ERR_RDONLY: return "write not permitted";
 780         }
 781         return "Invalid error code";
 782 }
 783
 784 enum TDB_ERROR COLD tdb_logerr(struct tdb_context *tdb,
 785                                enum TDB_ERROR ecode,
 786                                enum tdb_log_level level,
 787                                const char *fmt, ...)
 788 {
 789         char *message;
 790         va_list ap;
 791         size_t len;
 792         /* tdb_open paths care about errno, so save it. */
 793         int saved_errno = errno;
 794
 795         tdb->ecode = ecode;
 796
 797         if (!tdb->logfn)
 798                 return ecode;
 799
 800         /* FIXME: Doesn't assume asprintf. */
 801         va_start(ap, fmt);
 802         len = vsnprintf(NULL, 0, fmt, ap);
 803         va_end(ap);
 804
 805         message = malloc(len + 1);
 806         if (!message) {
 807                 tdb->logfn(tdb, TDB_LOG_ERROR, tdb->log_private,
 808                            "out of memory formatting message:");
 809                 tdb->logfn(tdb, level, tdb->log_private, fmt);
 810                 return ecode;
 811         }
 812         va_start(ap, fmt);
 813         len = vsprintf(message, fmt, ap);
 814         va_end(ap);
 815         tdb->logfn(tdb, level, tdb->log_private, message);
 816         free(message);
 817         errno = saved_errno;
 818         return ecode;
 819 }