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

   1  /*
   2    Trivial Database 2: opening and closing TDBs
   3    Copyright (C) Rusty Russell 2010
   4
   5    This library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 3 of the License, or (at your option) any later version.
   9
  10    This library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17 */
  18 #include "private.h"
  19 #include <ccan/build_assert/build_assert.h>
  20 #include <assert.h>
  21
  22 /* all tdbs, to detect double-opens (fcntl file don't nest!) */
  23 static struct tdb_context *tdbs = NULL;
  24
  25 static struct tdb_file *find_file(dev_t device, ino_t ino)
  26 {
  27         struct tdb_context *i;
  28
  29         for (i = tdbs; i; i = i->next) {
  30                 if (i->file->device == device && i->file->inode == ino) {
  31                         i->file->refcnt++;
  32                         return i->file;
  33                 }
  34         }
  35         return NULL;
  36 }
  37
  38 static bool read_all(int fd, void *buf, size_t len)
  39 {
  40         while (len) {
  41                 ssize_t ret;
  42                 ret = read(fd, buf, len);
  43                 if (ret < 0)
  44                         return false;
  45                 if (ret == 0) {
  46                         /* ETOOSHORT? */
  47                         errno = EWOULDBLOCK;
  48                         return false;
  49                 }
  50                 buf = (char *)buf + ret;
  51                 len -= ret;
  52         }
  53         return true;
  54 }
  55
  56 static uint64_t random_number(struct tdb_context *tdb)
  57 {
  58         int fd;
  59         uint64_t ret = 0;
  60         struct timeval now;
  61
  62         fd = open("/dev/urandom", O_RDONLY);
  63         if (fd >= 0) {
  64                 if (read_all(fd, &ret, sizeof(ret))) {
  65                         close(fd);
  66                         return ret;
  67                 }
  68                 close(fd);
  69         }
  70         /* FIXME: Untested!  Based on Wikipedia protocol description! */
  71         fd = open("/dev/egd-pool", O_RDWR);
  72         if (fd >= 0) {
  73                 /* Command is 1, next byte is size we want to read. */
  74                 char cmd[2] = { 1, sizeof(uint64_t) };
  75                 if (write(fd, cmd, sizeof(cmd)) == sizeof(cmd)) {
  76                         char reply[1 + sizeof(uint64_t)];
  77                         int r = read(fd, reply, sizeof(reply));
  78                         if (r > 1) {
  79                                 /* Copy at least some bytes. */
  80                                 memcpy(&ret, reply+1, r - 1);
  81                                 if (reply[0] == sizeof(uint64_t)
  82                                     && r == sizeof(reply)) {
  83                                         close(fd);
  84                                         return ret;
  85                                 }
  86                         }
  87                 }
  88                 close(fd);
  89         }
  90
  91         /* Fallback: pid and time. */
  92         gettimeofday(&now, NULL);
  93         ret = getpid() * 100132289ULL + now.tv_sec * 1000000ULL + now.tv_usec;
  94         tdb_logerr(tdb, TDB_SUCCESS, TDB_LOG_WARNING,
  95                    "tdb_open: random from getpid and time");
  96         return ret;
  97 }
  98
  99 static void tdb2_context_init(struct tdb_context *tdb)
 100 {
 101         /* Initialize the TDB2 fields here */
 102         tdb_io_init(tdb);
 103         tdb->tdb2.direct_access = 0;
 104         tdb->tdb2.transaction = NULL;
 105         tdb->tdb2.access = NULL;
 106 }
 107
 108 struct new_database {
 109         struct tdb_header hdr;
 110         struct tdb_freetable ftable;
 111 };
 112
 113 /* initialise a new database */
 114 static enum TDB_ERROR tdb_new_database(struct tdb_context *tdb,
 115                                        struct tdb_attribute_seed *seed,
 116                                        struct tdb_header *hdr)
 117 {
 118         /* We make it up in memory, then write it out if not internal */
 119         struct new_database newdb;
 120         unsigned int magic_len;
 121         ssize_t rlen;
 122         enum TDB_ERROR ecode;
 123
 124         /* Fill in the header */
 125         newdb.hdr.version = TDB_VERSION;
 126         if (seed)
 127                 newdb.hdr.hash_seed = seed->seed;
 128         else
 129                 newdb.hdr.hash_seed = random_number(tdb);
 130         newdb.hdr.hash_test = TDB_HASH_MAGIC;
 131         newdb.hdr.hash_test = tdb->hash_fn(&newdb.hdr.hash_test,
 132                                            sizeof(newdb.hdr.hash_test),
 133                                            newdb.hdr.hash_seed,
 134                                            tdb->hash_data);
 135         newdb.hdr.recovery = 0;
 136         newdb.hdr.features_used = newdb.hdr.features_offered = TDB_FEATURE_MASK;
 137         newdb.hdr.seqnum = 0;
 138         memset(newdb.hdr.reserved, 0, sizeof(newdb.hdr.reserved));
 139         /* Initial hashes are empty. */
 140         memset(newdb.hdr.hashtable, 0, sizeof(newdb.hdr.hashtable));
 141
 142         /* Free is empty. */
 143         newdb.hdr.free_table = offsetof(struct new_database, ftable);
 144         memset(&newdb.ftable, 0, sizeof(newdb.ftable));
 145         ecode = set_header(NULL, &newdb.ftable.hdr, TDB_FTABLE_MAGIC, 0,
 146                            sizeof(newdb.ftable) - sizeof(newdb.ftable.hdr),
 147                            sizeof(newdb.ftable) - sizeof(newdb.ftable.hdr),
 148                            0);
 149         if (ecode != TDB_SUCCESS) {
 150                 return ecode;
 151         }
 152
 153         /* Magic food */
 154         memset(newdb.hdr.magic_food, 0, sizeof(newdb.hdr.magic_food));
 155         strcpy(newdb.hdr.magic_food, TDB_MAGIC_FOOD);
 156
 157         /* This creates an endian-converted database, as if read from disk */
 158         magic_len = sizeof(newdb.hdr.magic_food);
 159         tdb_convert(tdb,
 160                     (char *)&newdb.hdr + magic_len, sizeof(newdb) - magic_len);
 161
 162         *hdr = newdb.hdr;
 163
 164         if (tdb->flags & TDB_INTERNAL) {
 165                 tdb->file->map_size = sizeof(newdb);
 166                 tdb->file->map_ptr = malloc(tdb->file->map_size);
 167                 if (!tdb->file->map_ptr) {
 168                         return tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
 169                                           "tdb_new_database:"
 170                                           " failed to allocate");
 171                 }
 172                 memcpy(tdb->file->map_ptr, &newdb, tdb->file->map_size);
 173                 return TDB_SUCCESS;
 174         }
 175         if (lseek(tdb->file->fd, 0, SEEK_SET) == -1) {
 176                 return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 177                                   "tdb_new_database:"
 178                                   " failed to seek: %s", strerror(errno));
 179         }
 180
 181         if (ftruncate(tdb->file->fd, 0) == -1) {
 182                 return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 183                                   "tdb_new_database:"
 184                                   " failed to truncate: %s", strerror(errno));
 185         }
 186
 187         rlen = write(tdb->file->fd, &newdb, sizeof(newdb));
 188         if (rlen != sizeof(newdb)) {
 189                 if (rlen >= 0)
 190                         errno = ENOSPC;
 191                 return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 192                                   "tdb_new_database: %zi writing header: %s",
 193                                   rlen, strerror(errno));
 194         }
 195         return TDB_SUCCESS;
 196 }
 197
 198 static enum TDB_ERROR tdb_new_file(struct tdb_context *tdb)
 199 {
 200         tdb->file = malloc(sizeof(*tdb->file));
 201         if (!tdb->file)
 202                 return tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
 203                                   "tdb_open: cannot alloc tdb_file structure");
 204         tdb->file->num_lockrecs = 0;
 205         tdb->file->lockrecs = NULL;
 206         tdb->file->allrecord_lock.count = 0;
 207         tdb->file->refcnt = 1;
 208         tdb->file->map_ptr = NULL;
 209         return TDB_SUCCESS;
 210 }
 211
 212 enum TDB_ERROR tdb_set_attribute(struct tdb_context *tdb,
 213                                  const union tdb_attribute *attr)
 214 {
 215         switch (attr->base.attr) {
 216         case TDB_ATTRIBUTE_LOG:
 217                 tdb->log_fn = attr->log.fn;
 218                 tdb->log_data = attr->log.data;
 219                 break;
 220         case TDB_ATTRIBUTE_HASH:
 221         case TDB_ATTRIBUTE_SEED:
 222         case TDB_ATTRIBUTE_OPENHOOK:
 223         case TDB_ATTRIBUTE_TDB1_HASHSIZE:
 224                 return tdb->last_error
 225                         = tdb_logerr(tdb, TDB_ERR_EINVAL,
 226                                      TDB_LOG_USE_ERROR,
 227                                      "tdb_set_attribute:"
 228                                      " cannot set %s after opening",
 229                                      attr->base.attr == TDB_ATTRIBUTE_HASH
 230                                      ? "TDB_ATTRIBUTE_HASH"
 231                                      : attr->base.attr == TDB_ATTRIBUTE_SEED
 232                                      ? "TDB_ATTRIBUTE_SEED"
 233                                      : attr->base.attr == TDB_ATTRIBUTE_OPENHOOK
 234                                      ? "TDB_ATTRIBUTE_OPENHOOK"
 235                                      : "TDB_ATTRIBUTE_TDB1_HASHSIZE");
 236         case TDB_ATTRIBUTE_STATS:
 237                 return tdb->last_error
 238                         = tdb_logerr(tdb, TDB_ERR_EINVAL,
 239                                      TDB_LOG_USE_ERROR,
 240                                      "tdb_set_attribute:"
 241                                      " cannot set TDB_ATTRIBUTE_STATS");
 242         case TDB_ATTRIBUTE_FLOCK:
 243                 tdb->lock_fn = attr->flock.lock;
 244                 tdb->unlock_fn = attr->flock.unlock;
 245                 tdb->lock_data = attr->flock.data;
 246                 break;
 247         default:
 248                 return tdb->last_error
 249                         = tdb_logerr(tdb, TDB_ERR_EINVAL,
 250                                      TDB_LOG_USE_ERROR,
 251                                      "tdb_set_attribute:"
 252                                      " unknown attribute type %u",
 253                                      attr->base.attr);
 254         }
 255         return TDB_SUCCESS;
 256 }
 257
 258 enum TDB_ERROR tdb_get_attribute(struct tdb_context *tdb,
 259                                  union tdb_attribute *attr)
 260 {
 261         switch (attr->base.attr) {
 262         case TDB_ATTRIBUTE_LOG:
 263                 if (!tdb->log_fn)
 264                         return tdb->last_error = TDB_ERR_NOEXIST;
 265                 attr->log.fn = tdb->log_fn;
 266                 attr->log.data = tdb->log_data;
 267                 break;
 268         case TDB_ATTRIBUTE_HASH:
 269                 attr->hash.fn = tdb->hash_fn;
 270                 attr->hash.data = tdb->hash_data;
 271                 break;
 272         case TDB_ATTRIBUTE_SEED:
 273                 if (tdb->flags & TDB_VERSION1)
 274                         return tdb->last_error
 275                                 = tdb_logerr(tdb, TDB_ERR_EINVAL,
 276                                              TDB_LOG_USE_ERROR,
 277                                      "tdb_get_attribute:"
 278                                      " cannot get TDB_ATTRIBUTE_SEED"
 279                                      " on TDB1 tdb.");
 280                 attr->seed.seed = tdb->hash_seed;
 281                 break;
 282         case TDB_ATTRIBUTE_OPENHOOK:
 283                 if (!tdb->openhook)
 284                         return tdb->last_error = TDB_ERR_NOEXIST;
 285                 attr->openhook.fn = tdb->openhook;
 286                 attr->openhook.data = tdb->openhook_data;
 287                 break;
 288         case TDB_ATTRIBUTE_STATS: {
 289                 size_t size = attr->stats.size;
 290                 if (size > tdb->stats.size)
 291                         size = tdb->stats.size;
 292                 memcpy(&attr->stats, &tdb->stats, size);
 293                 break;
 294         }
 295         case TDB_ATTRIBUTE_FLOCK:
 296                 attr->flock.lock = tdb->lock_fn;
 297                 attr->flock.unlock = tdb->unlock_fn;
 298                 attr->flock.data = tdb->lock_data;
 299                 break;
 300         case TDB_ATTRIBUTE_TDB1_HASHSIZE:
 301                 if (!(tdb->flags & TDB_VERSION1))
 302                         return tdb->last_error
 303                                 = tdb_logerr(tdb, TDB_ERR_EINVAL,
 304                                              TDB_LOG_USE_ERROR,
 305                                      "tdb_get_attribute:"
 306                                      " cannot get TDB_ATTRIBUTE_TDB1_HASHSIZE"
 307                                      " on TDB2 tdb.");
 308                 attr->tdb1_hashsize.hsize = tdb->tdb1.header.hash_size;
 309                 break;
 310         default:
 311                 return tdb->last_error
 312                         = tdb_logerr(tdb, TDB_ERR_EINVAL,
 313                                      TDB_LOG_USE_ERROR,
 314                                      "tdb_get_attribute:"
 315                                      " unknown attribute type %u",
 316                                      attr->base.attr);
 317         }
 318         attr->base.next = NULL;
 319         return TDB_SUCCESS;
 320 }
 321
 322 void tdb_unset_attribute(struct tdb_context *tdb,
 323                          enum tdb_attribute_type type)
 324 {
 325         switch (type) {
 326         case TDB_ATTRIBUTE_LOG:
 327                 tdb->log_fn = NULL;
 328                 break;
 329         case TDB_ATTRIBUTE_OPENHOOK:
 330                 tdb->openhook = NULL;
 331                 break;
 332         case TDB_ATTRIBUTE_HASH:
 333         case TDB_ATTRIBUTE_SEED:
 334         case TDB_ATTRIBUTE_TDB1_HASHSIZE:
 335                 tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
 336                            "tdb_unset_attribute: cannot unset %s after opening",
 337                            type == TDB_ATTRIBUTE_HASH
 338                            ? "TDB_ATTRIBUTE_HASH"
 339                            : type == TDB_ATTRIBUTE_SEED
 340                            ? "TDB_ATTRIBUTE_SEED"
 341                            : "TDB_ATTRIBUTE_TDB1_HASHSIZE");
 342                 break;
 343         case TDB_ATTRIBUTE_STATS:
 344                 tdb_logerr(tdb, TDB_ERR_EINVAL,
 345                            TDB_LOG_USE_ERROR,
 346                            "tdb_unset_attribute:"
 347                            "cannot unset TDB_ATTRIBUTE_STATS");
 348                 break;
 349         case TDB_ATTRIBUTE_FLOCK:
 350                 tdb->lock_fn = tdb_fcntl_lock;
 351                 tdb->unlock_fn = tdb_fcntl_unlock;
 352                 break;
 353         default:
 354                 tdb_logerr(tdb, TDB_ERR_EINVAL,
 355                            TDB_LOG_USE_ERROR,
 356                            "tdb_unset_attribute: unknown attribute type %u",
 357                            type);
 358         }
 359 }
 360
 361 static bool is_tdb1(struct tdb1_header *hdr, const void *buf, ssize_t rlen)
 362 {
 363         /* This code assumes we've tried to read entire tdb1 header. */
 364         BUILD_ASSERT(sizeof(*hdr) <= sizeof(struct tdb_header));
 365
 366         if (rlen < (ssize_t)sizeof(*hdr)) {
 367                 return false;
 368         }
 369
 370         memcpy(hdr, buf, sizeof(*hdr));
 371         if (strcmp(hdr->magic_food, TDB_MAGIC_FOOD) != 0)
 372                 return false;
 373
 374         return hdr->version == TDB1_VERSION
 375                 || hdr->version == TDB1_BYTEREV(TDB1_VERSION);
 376 }
 377
 378 struct tdb_context *tdb_open(const char *name, int tdb_flags,
 379                              int open_flags, mode_t mode,
 380                              union tdb_attribute *attr)
 381 {
 382         struct tdb_context *tdb;
 383         struct stat st;
 384         int saved_errno = 0;
 385         uint64_t hash_test;
 386         unsigned v;
 387         ssize_t rlen;
 388         struct tdb_header hdr;
 389         struct tdb_attribute_seed *seed = NULL;
 390         struct tdb_attribute_tdb1_hashsize *hsize_attr = NULL;
 391         struct tdb_attribute_tdb1_max_dead *maxsize_attr = NULL;
 392         tdb_bool_err berr;
 393         enum TDB_ERROR ecode;
 394         int openlock;
 395
 396         tdb = malloc(sizeof(*tdb) + (name ? strlen(name) + 1 : 0));
 397         if (!tdb) {
 398                 /* Can't log this */
 399                 errno = ENOMEM;
 400                 return NULL;
 401         }
 402         /* Set name immediately for logging functions. */
 403         if (name) {
 404                 tdb->name = strcpy((char *)(tdb + 1), name);
 405         } else {
 406                 tdb->name = NULL;
 407         }
 408         tdb->flags = tdb_flags;
 409         tdb->log_fn = NULL;
 410         tdb->open_flags = open_flags;
 411         tdb->last_error = TDB_SUCCESS;
 412         tdb->file = NULL;
 413         tdb->openhook = NULL;
 414         tdb->lock_fn = tdb_fcntl_lock;
 415         tdb->unlock_fn = tdb_fcntl_unlock;
 416         tdb->hash_fn = tdb_jenkins_hash;
 417         memset(&tdb->stats, 0, sizeof(tdb->stats));
 418         tdb->stats.base.attr = TDB_ATTRIBUTE_STATS;
 419         tdb->stats.size = sizeof(tdb->stats);
 420
 421         while (attr) {
 422                 switch (attr->base.attr) {
 423                 case TDB_ATTRIBUTE_HASH:
 424                         tdb->hash_fn = attr->hash.fn;
 425                         tdb->hash_data = attr->hash.data;
 426                         break;
 427                 case TDB_ATTRIBUTE_SEED:
 428                         seed = &attr->seed;
 429                         break;
 430                 case TDB_ATTRIBUTE_OPENHOOK:
 431                         tdb->openhook = attr->openhook.fn;
 432                         tdb->openhook_data = attr->openhook.data;
 433                         break;
 434                 case TDB_ATTRIBUTE_TDB1_HASHSIZE:
 435                         hsize_attr = &attr->tdb1_hashsize;
 436                         break;
 437                 case TDB_ATTRIBUTE_TDB1_MAX_DEAD:
 438                         maxsize_attr = &attr->tdb1_max_dead;
 439                         break;
 440                 default:
 441                         /* These are set as normal. */
 442                         ecode = tdb_set_attribute(tdb, attr);
 443                         if (ecode != TDB_SUCCESS)
 444                                 goto fail;
 445                 }
 446                 attr = attr->base.next;
 447         }
 448
 449         if (tdb_flags & ~(TDB_INTERNAL | TDB_NOLOCK | TDB_NOMMAP | TDB_CONVERT
 450                           | TDB_NOSYNC | TDB_SEQNUM | TDB_ALLOW_NESTING
 451                           | TDB_RDONLY | TDB_VERSION1)) {
 452                 ecode = tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
 453                                    "tdb_open: unknown flags %u", tdb_flags);
 454                 goto fail;
 455         }
 456
 457         if (hsize_attr) {
 458                 if (!(tdb_flags & TDB_VERSION1) ||
 459                     (!(tdb_flags & TDB_INTERNAL) && !(open_flags & O_CREAT))) {
 460                         ecode = tdb_logerr(tdb, TDB_ERR_EINVAL,
 461                                            TDB_LOG_USE_ERROR,
 462                                            "tdb_open: can only use"
 463                                            " TDB_ATTRIBUTE_TDB1_HASHSIZE when"
 464                                            " creating a TDB_VERSION1 tdb");
 465                         goto fail;
 466                 }
 467         }
 468
 469         if (seed) {
 470                 if (tdb_flags & TDB_VERSION1) {
 471                         ecode = tdb_logerr(tdb, TDB_ERR_EINVAL,
 472                                            TDB_LOG_USE_ERROR,
 473                                            "tdb_open:"
 474                                            " cannot set TDB_ATTRIBUTE_SEED"
 475                                            " on TDB1 tdb.");
 476                         goto fail;
 477                 } else if (!(tdb_flags & TDB_INTERNAL)
 478                            && !(open_flags & O_CREAT)) {
 479                         ecode = tdb_logerr(tdb, TDB_ERR_EINVAL,
 480                                            TDB_LOG_USE_ERROR,
 481                                            "tdb_open:"
 482                                            " cannot set TDB_ATTRIBUTE_SEED"
 483                                            " without O_CREAT.");
 484                         goto fail;
 485                 }
 486         }
 487
 488         if ((open_flags & O_ACCMODE) == O_WRONLY) {
 489                 ecode = tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
 490                                    "tdb_open: can't open tdb %s write-only",
 491                                    name);
 492                 goto fail;
 493         }
 494
 495         if ((open_flags & O_ACCMODE) == O_RDONLY) {
 496                 openlock = F_RDLCK;
 497                 tdb->flags |= TDB_RDONLY;
 498         } else {
 499                 if (tdb_flags & TDB_RDONLY) {
 500                         ecode = tdb_logerr(tdb, TDB_ERR_EINVAL,
 501                                            TDB_LOG_USE_ERROR,
 502                                            "tdb_open: can't use TDB_RDONLY"
 503                                            " without O_RDONLY");
 504                         goto fail;
 505                 }
 506                 openlock = F_WRLCK;
 507         }
 508
 509         /* internal databases don't need any of the rest. */
 510         if (tdb->flags & TDB_INTERNAL) {
 511                 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
 512                 ecode = tdb_new_file(tdb);
 513                 if (ecode != TDB_SUCCESS) {
 514                         goto fail;
 515                 }
 516                 tdb->file->fd = -1;
 517                 if (tdb->flags & TDB_VERSION1)
 518                         ecode = tdb1_new_database(tdb, hsize_attr, maxsize_attr);
 519                 else {
 520                         ecode = tdb_new_database(tdb, seed, &hdr);
 521                         if (ecode == TDB_SUCCESS) {
 522                                 tdb_convert(tdb, &hdr.hash_seed,
 523                                             sizeof(hdr.hash_seed));
 524                                 tdb->hash_seed = hdr.hash_seed;
 525                                 tdb2_context_init(tdb);
 526                                 tdb_ftable_init(tdb);
 527                         }
 528                 }
 529                 if (ecode != TDB_SUCCESS) {
 530                         goto fail;
 531                 }
 532                 return tdb;
 533         }
 534
 535         if (stat(name, &st) != -1)
 536                 tdb->file = find_file(st.st_dev, st.st_ino);
 537
 538         if (!tdb->file) {
 539                 int fd;
 540
 541                 if ((fd = open(name, open_flags, mode)) == -1) {
 542                         /* errno set by open(2) */
 543                         saved_errno = errno;
 544                         tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 545                                    "tdb_open: could not open file %s: %s",
 546                                    name, strerror(errno));
 547                         goto fail_errno;
 548                 }
 549
 550                 /* on exec, don't inherit the fd */
 551                 v = fcntl(fd, F_GETFD, 0);
 552                 fcntl(fd, F_SETFD, v | FD_CLOEXEC);
 553
 554                 if (fstat(fd, &st) == -1) {
 555                         saved_errno = errno;
 556                         tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 557                                    "tdb_open: could not stat open %s: %s",
 558                                    name, strerror(errno));
 559                         close(fd);
 560                         goto fail_errno;
 561                 }
 562
 563                 ecode = tdb_new_file(tdb);
 564                 if (ecode != TDB_SUCCESS) {
 565                         close(fd);
 566                         goto fail;
 567                 }
 568
 569                 tdb->file->fd = fd;
 570                 tdb->file->device = st.st_dev;
 571                 tdb->file->inode = st.st_ino;
 572                 tdb->file->map_ptr = NULL;
 573                 tdb->file->map_size = 0;
 574         }
 575
 576         /* ensure there is only one process initialising at once */
 577         ecode = tdb_lock_open(tdb, openlock, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK);
 578         if (ecode != TDB_SUCCESS) {
 579                 saved_errno = errno;
 580                 goto fail_errno;
 581         }
 582
 583         /* call their open hook if they gave us one. */
 584         if (tdb->openhook) {
 585                 ecode = tdb->openhook(tdb->file->fd, tdb->openhook_data);
 586                 if (ecode != TDB_SUCCESS) {
 587                         tdb_logerr(tdb, ecode, TDB_LOG_ERROR,
 588                                    "tdb_open: open hook failed");
 589                         goto fail;
 590                 }
 591                 open_flags |= O_CREAT;
 592         }
 593
 594         /* If they used O_TRUNC, read will return 0. */
 595         rlen = pread(tdb->file->fd, &hdr, sizeof(hdr), 0);
 596         if (rlen == 0 && (open_flags & O_CREAT)) {
 597                 if (tdb->flags & TDB_VERSION1) {
 598                         ecode = tdb1_new_database(tdb, hsize_attr, maxsize_attr);
 599                         if (ecode != TDB_SUCCESS)
 600                                 goto fail;
 601                         goto finished;
 602                 }
 603                 ecode = tdb_new_database(tdb, seed, &hdr);
 604                 if (ecode != TDB_SUCCESS) {
 605                         goto fail;
 606                 }
 607         } else if (rlen < 0) {
 608                 ecode = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 609                                    "tdb_open: error %s reading %s",
 610                                    strerror(errno), name);
 611                 goto fail;
 612         } else if (rlen < sizeof(hdr)
 613                    || strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0) {
 614                 if (is_tdb1(&tdb->tdb1.header, &hdr, rlen)) {
 615                         ecode = tdb1_open(tdb, maxsize_attr);
 616                         if (!ecode)
 617                                 goto finished;
 618                         goto fail;
 619                 }
 620                 ecode = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 621                                    "tdb_open: %s is not a tdb file", name);
 622                 goto fail;
 623         }
 624
 625         if (hdr.version != TDB_VERSION) {
 626                 if (hdr.version == bswap_64(TDB_VERSION))
 627                         tdb->flags |= TDB_CONVERT;
 628                 else {
 629                         if (is_tdb1(&tdb->tdb1.header, &hdr, rlen)) {
 630                                 ecode = tdb1_open(tdb, maxsize_attr);
 631                                 if (!ecode)
 632                                         goto finished;
 633                                 goto fail;
 634                         }
 635                         /* wrong version */
 636                         ecode = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 637                                            "tdb_open:"
 638                                            " %s is unknown version 0x%llx",
 639                                            name, (long long)hdr.version);
 640                         goto fail;
 641                 }
 642         } else if (tdb->flags & TDB_CONVERT) {
 643                 ecode = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 644                                    "tdb_open:"
 645                                    " %s does not need TDB_CONVERT",
 646                                    name);
 647                 goto fail;
 648         }
 649
 650         if (tdb->flags & TDB_VERSION1) {
 651                 ecode = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 652                                    "tdb_open:"
 653                                    " %s does not need TDB_VERSION1",
 654                                    name);
 655                 goto fail;
 656         }
 657
 658         tdb2_context_init(tdb);
 659
 660         tdb_convert(tdb, &hdr, sizeof(hdr));
 661         tdb->hash_seed = hdr.hash_seed;
 662         hash_test = TDB_HASH_MAGIC;
 663         hash_test = tdb_hash(tdb, &hash_test, sizeof(hash_test));
 664         if (hdr.hash_test != hash_test) {
 665                 /* wrong hash variant */
 666                 ecode = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 667                                    "tdb_open:"
 668                                    " %s uses a different hash function",
 669                                    name);
 670                 goto fail;
 671         }
 672
 673         /* Clear any features we don't understand. */
 674         if ((open_flags & O_ACCMODE) != O_RDONLY) {
 675                 hdr.features_used &= TDB_FEATURE_MASK;
 676                 ecode = tdb_write_convert(tdb, offsetof(struct tdb_header,
 677                                                         features_used),
 678                                           &hdr.features_used,
 679                                           sizeof(hdr.features_used));
 680                 if (ecode != TDB_SUCCESS)
 681                         goto fail;
 682         }
 683
 684 finished:
 685         if (tdb->flags & TDB_VERSION1) {
 686                 /* if needed, run recovery */
 687                 if (tdb1_transaction_recover(tdb) == -1) {
 688                         ecode = tdb->last_error;
 689                         goto fail;
 690                 }
 691         }
 692
 693         tdb_unlock_open(tdb, openlock);
 694
 695         /* This makes sure we have current map_size and mmap. */
 696         if (tdb->flags & TDB_VERSION1) {
 697                 ecode = tdb1_probe_length(tdb);
 698         } else {
 699                 ecode = tdb->tdb2.io->oob(tdb, tdb->file->map_size + 1, true);
 700         }
 701         if (unlikely(ecode != TDB_SUCCESS))
 702                 goto fail;
 703
 704         if (!(tdb->flags & TDB_VERSION1)) {
 705                 /* Now it's fully formed, recover if necessary. */
 706                 berr = tdb_needs_recovery(tdb);
 707                 if (unlikely(berr != false)) {
 708                         if (berr < 0) {
 709                                 ecode = TDB_OFF_TO_ERR(berr);
 710                                 goto fail;
 711                         }
 712                         ecode = tdb_lock_and_recover(tdb);
 713                         if (ecode != TDB_SUCCESS) {
 714                                 goto fail;
 715                         }
 716                 }
 717
 718                 ecode = tdb_ftable_init(tdb);
 719                 if (ecode != TDB_SUCCESS) {
 720                         goto fail;
 721                 }
 722         }
 723
 724         tdb->next = tdbs;
 725         tdbs = tdb;
 726         return tdb;
 727
 728  fail:
 729         /* Map ecode to some logical errno. */
 730         switch (TDB_ERR_TO_OFF(ecode)) {
 731         case TDB_ERR_TO_OFF(TDB_ERR_CORRUPT):
 732         case TDB_ERR_TO_OFF(TDB_ERR_IO):
 733                 saved_errno = EIO;
 734                 break;
 735         case TDB_ERR_TO_OFF(TDB_ERR_LOCK):
 736                 saved_errno = EWOULDBLOCK;
 737                 break;
 738         case TDB_ERR_TO_OFF(TDB_ERR_OOM):
 739                 saved_errno = ENOMEM;
 740                 break;
 741         case TDB_ERR_TO_OFF(TDB_ERR_EINVAL):
 742                 saved_errno = EINVAL;
 743                 break;
 744         default:
 745                 saved_errno = EINVAL;
 746                 break;
 747         }
 748
 749 fail_errno:
 750 #ifdef TDB_TRACE
 751         close(tdb->tracefd);
 752 #endif
 753         if (tdb->file) {
 754                 tdb_lock_cleanup(tdb);
 755                 if (--tdb->file->refcnt == 0) {
 756                         assert(tdb->file->num_lockrecs == 0);
 757                         if (tdb->file->map_ptr) {
 758                                 if (tdb->flags & TDB_INTERNAL) {
 759                                         free(tdb->file->map_ptr);
 760                                 } else
 761                                         tdb_munmap(tdb->file);
 762                         }
 763                         if (close(tdb->file->fd) != 0)
 764                                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 765                                            "tdb_open: failed to close tdb fd"
 766                                            " on error: %s", strerror(errno));
 767                         free(tdb->file->lockrecs);
 768                         free(tdb->file);
 769                 }
 770         }
 771
 772         free(tdb);
 773         errno = saved_errno;
 774         return NULL;
 775 }
 776
 777 int tdb_close(struct tdb_context *tdb)
 778 {
 779         int ret = 0;
 780         struct tdb_context **i;
 781
 782         tdb_trace(tdb, "tdb_close");
 783
 784         if (tdb->flags & TDB_VERSION1) {
 785                 if (tdb->tdb1.transaction) {
 786                         tdb1_transaction_cancel(tdb);
 787                 }
 788         } else {
 789                 if (tdb->tdb2.transaction) {
 790                         tdb_transaction_cancel(tdb);
 791                 }
 792         }
 793
 794         if (tdb->file->map_ptr) {
 795                 if (tdb->flags & TDB_INTERNAL)
 796                         free(tdb->file->map_ptr);
 797                 else
 798                         tdb_munmap(tdb->file);
 799         }
 800         if (tdb->file) {
 801                 tdb_lock_cleanup(tdb);
 802                 if (--tdb->file->refcnt == 0) {
 803                         ret = close(tdb->file->fd);
 804                         free(tdb->file->lockrecs);
 805                         free(tdb->file);
 806                 }
 807         }
 808
 809         /* Remove from tdbs list */
 810         for (i = &tdbs; *i; i = &(*i)->next) {
 811                 if (*i == tdb) {
 812                         *i = tdb->next;
 813                         break;
 814                 }
 815         }
 816
 817 #ifdef TDB_TRACE
 818         close(tdb->tracefd);
 819 #endif
 820         free(tdb);
 821
 822         return ret;
 823 }
 824
 825 void tdb_foreach_(int (*fn)(struct tdb_context *, void *), void *p)
 826 {
 827         struct tdb_context *i;
 828
 829         for (i = tdbs; i; i = i->next) {
 830                 if (fn(i, p) != 0)
 831                         break;
 832         }
 833 }