lib/tdb2/tdb.c

   1  /*
   2    Trivial Database 2: fetch, store and misc routines.
   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 #ifndef _SAMBA_BUILD_
  20 #include <ccan/asprintf/asprintf.h>
  21 #include <stdarg.h>
  22 #endif
  23
  24 static enum TDB_ERROR update_rec_hdr(struct tdb_context *tdb,
  25                                      tdb_off_t off,
  26                                      tdb_len_t keylen,
  27                                      tdb_len_t datalen,
  28                                      struct tdb_used_record *rec,
  29                                      uint64_t h)
  30 {
  31         uint64_t dataroom = rec_data_length(rec) + rec_extra_padding(rec);
  32         enum TDB_ERROR ecode;
  33
  34         ecode = set_header(tdb, rec, TDB_USED_MAGIC, keylen, datalen,
  35                            keylen + dataroom, h);
  36         if (ecode == TDB_SUCCESS) {
  37                 ecode = tdb_write_convert(tdb, off, rec, sizeof(*rec));
  38         }
  39         return ecode;
  40 }
  41
  42 static enum TDB_ERROR replace_data(struct tdb_context *tdb,
  43                                    struct hash_info *h,
  44                                    struct tdb_data key, struct tdb_data dbuf,
  45                                    tdb_off_t old_off, tdb_len_t old_room,
  46                                    bool growing)
  47 {
  48         tdb_off_t new_off;
  49         enum TDB_ERROR ecode;
  50
  51         /* Allocate a new record. */
  52         new_off = alloc(tdb, key.dsize, dbuf.dsize, h->h, TDB_USED_MAGIC,
  53                         growing);
  54         if (TDB_OFF_IS_ERR(new_off)) {
  55                 return new_off;
  56         }
  57
  58         /* We didn't like the existing one: remove it. */
  59         if (old_off) {
  60                 tdb->stats.frees++;
  61                 ecode = add_free_record(tdb, old_off,
  62                                         sizeof(struct tdb_used_record)
  63                                         + key.dsize + old_room,
  64                                         TDB_LOCK_WAIT, true);
  65                 if (ecode == TDB_SUCCESS)
  66                         ecode = replace_in_hash(tdb, h, new_off);
  67         } else {
  68                 ecode = add_to_hash(tdb, h, new_off);
  69         }
  70         if (ecode != TDB_SUCCESS) {
  71                 return ecode;
  72         }
  73
  74         new_off += sizeof(struct tdb_used_record);
  75         ecode = tdb->tdb2.io->twrite(tdb, new_off, key.dptr, key.dsize);
  76         if (ecode != TDB_SUCCESS) {
  77                 return ecode;
  78         }
  79
  80         new_off += key.dsize;
  81         ecode = tdb->tdb2.io->twrite(tdb, new_off, dbuf.dptr, dbuf.dsize);
  82         if (ecode != TDB_SUCCESS) {
  83                 return ecode;
  84         }
  85
  86         if (tdb->flags & TDB_SEQNUM)
  87                 tdb_inc_seqnum(tdb);
  88
  89         return TDB_SUCCESS;
  90 }
  91
  92 static enum TDB_ERROR update_data(struct tdb_context *tdb,
  93                                   tdb_off_t off,
  94                                   struct tdb_data dbuf,
  95                                   tdb_len_t extra)
  96 {
  97         enum TDB_ERROR ecode;
  98
  99         ecode = tdb->tdb2.io->twrite(tdb, off, dbuf.dptr, dbuf.dsize);
 100         if (ecode == TDB_SUCCESS && extra) {
 101                 /* Put a zero in; future versions may append other data. */
 102                 ecode = tdb->tdb2.io->twrite(tdb, off + dbuf.dsize, "", 1);
 103         }
 104         if (tdb->flags & TDB_SEQNUM)
 105                 tdb_inc_seqnum(tdb);
 106
 107         return ecode;
 108 }
 109
 110 enum TDB_ERROR tdb_store(struct tdb_context *tdb,
 111                          struct tdb_data key, struct tdb_data dbuf, int flag)
 112 {
 113         struct hash_info h;
 114         tdb_off_t off;
 115         tdb_len_t old_room = 0;
 116         struct tdb_used_record rec;
 117         enum TDB_ERROR ecode;
 118
 119         if (tdb->flags & TDB_VERSION1) {
 120                 if (tdb1_store(tdb, key, dbuf, flag) == -1)
 121                         return tdb->last_error;
 122                 return TDB_SUCCESS;
 123         }
 124
 125         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 126         if (TDB_OFF_IS_ERR(off)) {
 127                 return tdb->last_error = off;
 128         }
 129
 130         /* Now we have lock on this hash bucket. */
 131         if (flag == TDB_INSERT) {
 132                 if (off) {
 133                         ecode = TDB_ERR_EXISTS;
 134                         goto out;
 135                 }
 136         } else {
 137                 if (off) {
 138                         old_room = rec_data_length(&rec)
 139                                 + rec_extra_padding(&rec);
 140                         if (old_room >= dbuf.dsize) {
 141                                 /* Can modify in-place.  Easy! */
 142                                 ecode = update_rec_hdr(tdb, off,
 143                                                        key.dsize, dbuf.dsize,
 144                                                        &rec, h.h);
 145                                 if (ecode != TDB_SUCCESS) {
 146                                         goto out;
 147                                 }
 148                                 ecode = update_data(tdb,
 149                                                     off + sizeof(rec)
 150                                                     + key.dsize, dbuf,
 151                                                     old_room - dbuf.dsize);
 152                                 if (ecode != TDB_SUCCESS) {
 153                                         goto out;
 154                                 }
 155                                 tdb_unlock_hashes(tdb, h.hlock_start,
 156                                                   h.hlock_range, F_WRLCK);
 157                                 return tdb->last_error = TDB_SUCCESS;
 158                         }
 159                 } else {
 160                         if (flag == TDB_MODIFY) {
 161                                 /* if the record doesn't exist and we
 162                                    are in TDB_MODIFY mode then we should fail
 163                                    the store */
 164                                 ecode = TDB_ERR_NOEXIST;
 165                                 goto out;
 166                         }
 167                 }
 168         }
 169
 170         /* If we didn't use the old record, this implies we're growing. */
 171         ecode = replace_data(tdb, &h, key, dbuf, off, old_room, off);
 172 out:
 173         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 174         return tdb->last_error = ecode;
 175 }
 176
 177 enum TDB_ERROR tdb_append(struct tdb_context *tdb,
 178                           struct tdb_data key, struct tdb_data dbuf)
 179 {
 180         struct hash_info h;
 181         tdb_off_t off;
 182         struct tdb_used_record rec;
 183         tdb_len_t old_room = 0, old_dlen;
 184         unsigned char *newdata;
 185         struct tdb_data new_dbuf;
 186         enum TDB_ERROR ecode;
 187
 188         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 189         if (TDB_OFF_IS_ERR(off)) {
 190                 return tdb->last_error = off;
 191         }
 192
 193         if (off) {
 194                 old_dlen = rec_data_length(&rec);
 195                 old_room = old_dlen + rec_extra_padding(&rec);
 196
 197                 /* Fast path: can append in place. */
 198                 if (rec_extra_padding(&rec) >= dbuf.dsize) {
 199                         ecode = update_rec_hdr(tdb, off, key.dsize,
 200                                                old_dlen + dbuf.dsize, &rec,
 201                                                h.h);
 202                         if (ecode != TDB_SUCCESS) {
 203                                 goto out;
 204                         }
 205
 206                         off += sizeof(rec) + key.dsize + old_dlen;
 207                         ecode = update_data(tdb, off, dbuf,
 208                                             rec_extra_padding(&rec));
 209                         goto out;
 210                 }
 211
 212                 /* Slow path. */
 213                 newdata = malloc(key.dsize + old_dlen + dbuf.dsize);
 214                 if (!newdata) {
 215                         ecode = tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
 216                                            "tdb_append:"
 217                                            " failed to allocate %zu bytes",
 218                                            (size_t)(key.dsize + old_dlen
 219                                                     + dbuf.dsize));
 220                         goto out;
 221                 }
 222                 ecode = tdb->tdb2.io->tread(tdb, off + sizeof(rec) + key.dsize,
 223                                             newdata, old_dlen);
 224                 if (ecode != TDB_SUCCESS) {
 225                         goto out_free_newdata;
 226                 }
 227                 memcpy(newdata + old_dlen, dbuf.dptr, dbuf.dsize);
 228                 new_dbuf.dptr = newdata;
 229                 new_dbuf.dsize = old_dlen + dbuf.dsize;
 230         } else {
 231                 newdata = NULL;
 232                 new_dbuf = dbuf;
 233         }
 234
 235         /* If they're using tdb_append(), it implies they're growing record. */
 236         ecode = replace_data(tdb, &h, key, new_dbuf, off, old_room, true);
 237
 238 out_free_newdata:
 239         free(newdata);
 240 out:
 241         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 242         return tdb->last_error = ecode;
 243 }
 244
 245 enum TDB_ERROR tdb_fetch(struct tdb_context *tdb, struct tdb_data key,
 246                          struct tdb_data *data)
 247 {
 248         tdb_off_t off;
 249         struct tdb_used_record rec;
 250         struct hash_info h;
 251         enum TDB_ERROR ecode;
 252
 253         if (tdb->flags & TDB_VERSION1)
 254                 return tdb1_fetch(tdb, key, data);
 255
 256         off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
 257         if (TDB_OFF_IS_ERR(off)) {
 258                 return tdb->last_error = off;
 259         }
 260
 261         if (!off) {
 262                 ecode = TDB_ERR_NOEXIST;
 263         } else {
 264                 data->dsize = rec_data_length(&rec);
 265                 data->dptr = tdb_alloc_read(tdb, off + sizeof(rec) + key.dsize,
 266                                             data->dsize);
 267                 if (TDB_PTR_IS_ERR(data->dptr)) {
 268                         ecode = TDB_PTR_ERR(data->dptr);
 269                 } else
 270                         ecode = TDB_SUCCESS;
 271         }
 272
 273         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
 274         return tdb->last_error = ecode;
 275 }
 276
 277 bool tdb_exists(struct tdb_context *tdb, TDB_DATA key)
 278 {
 279         tdb_off_t off;
 280         struct tdb_used_record rec;
 281         struct hash_info h;
 282
 283         off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
 284         if (TDB_OFF_IS_ERR(off)) {
 285                 tdb->last_error = off;
 286                 return false;
 287         }
 288         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
 289
 290         tdb->last_error = TDB_SUCCESS;
 291         return off ? true : false;
 292 }
 293
 294 enum TDB_ERROR tdb_delete(struct tdb_context *tdb, struct tdb_data key)
 295 {
 296         tdb_off_t off;
 297         struct tdb_used_record rec;
 298         struct hash_info h;
 299         enum TDB_ERROR ecode;
 300
 301         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 302         if (TDB_OFF_IS_ERR(off)) {
 303                 return tdb->last_error = off;
 304         }
 305
 306         if (!off) {
 307                 ecode = TDB_ERR_NOEXIST;
 308                 goto unlock;
 309         }
 310
 311         ecode = delete_from_hash(tdb, &h);
 312         if (ecode != TDB_SUCCESS) {
 313                 goto unlock;
 314         }
 315
 316         /* Free the deleted entry. */
 317         tdb->stats.frees++;
 318         ecode = add_free_record(tdb, off,
 319                                 sizeof(struct tdb_used_record)
 320                                 + rec_key_length(&rec)
 321                                 + rec_data_length(&rec)
 322                                 + rec_extra_padding(&rec),
 323                                 TDB_LOCK_WAIT, true);
 324
 325         if (tdb->flags & TDB_SEQNUM)
 326                 tdb_inc_seqnum(tdb);
 327
 328 unlock:
 329         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 330         return tdb->last_error = ecode;
 331 }
 332
 333 unsigned int tdb_get_flags(struct tdb_context *tdb)
 334 {
 335         return tdb->flags;
 336 }
 337
 338 static bool inside_transaction(const struct tdb_context *tdb)
 339 {
 340         if (tdb->flags & TDB_VERSION1)
 341                 return tdb->tdb1.transaction != NULL;
 342         else
 343                 return tdb->tdb2.transaction != NULL;
 344 }
 345
 346 static bool readonly_changable(struct tdb_context *tdb, const char *caller)
 347 {
 348         if (inside_transaction(tdb)) {
 349                 tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
 350                                              TDB_LOG_USE_ERROR,
 351                                              "%s: can't change"
 352                                              " TDB_RDONLY inside transaction",
 353                                              caller);
 354                 return false;
 355         }
 356
 357         if (tdb->file->allrecord_lock.count != 0
 358             || tdb->file->num_lockrecs != 0) {
 359                 tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
 360                                              TDB_LOG_USE_ERROR,
 361                                              "%s: can't change"
 362                                              " TDB_RDONLY holding locks",
 363                                              caller);
 364                 return false;
 365         }
 366         return true;
 367 }
 368
 369 void tdb_add_flag(struct tdb_context *tdb, unsigned flag)
 370 {
 371         if (tdb->flags & TDB_INTERNAL) {
 372                 tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
 373                                              TDB_LOG_USE_ERROR,
 374                                              "tdb_add_flag: internal db");
 375                 return;
 376         }
 377         switch (flag) {
 378         case TDB_NOLOCK:
 379                 tdb->flags |= TDB_NOLOCK;
 380                 break;
 381         case TDB_NOMMAP:
 382                 tdb->flags |= TDB_NOMMAP;
 383                 tdb_munmap(tdb->file);
 384                 break;
 385         case TDB_NOSYNC:
 386                 tdb->flags |= TDB_NOSYNC;
 387                 break;
 388         case TDB_SEQNUM:
 389                 tdb->flags |= TDB_SEQNUM;
 390                 break;
 391         case TDB_ALLOW_NESTING:
 392                 tdb->flags |= TDB_ALLOW_NESTING;
 393                 break;
 394         case TDB_RDONLY:
 395                 if (readonly_changable(tdb, "tdb_add_flag"))
 396                         tdb->flags |= TDB_RDONLY;
 397                 break;
 398         default:
 399                 tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
 400                                              TDB_LOG_USE_ERROR,
 401                                              "tdb_add_flag: Unknown flag %u",
 402                                              flag);
 403         }
 404 }
 405
 406 void tdb_remove_flag(struct tdb_context *tdb, unsigned flag)
 407 {
 408         if (tdb->flags & TDB_INTERNAL) {
 409                 tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
 410                                              TDB_LOG_USE_ERROR,
 411                                              "tdb_remove_flag: internal db");
 412                 return;
 413         }
 414         switch (flag) {
 415         case TDB_NOLOCK:
 416                 tdb->flags &= ~TDB_NOLOCK;
 417                 break;
 418         case TDB_NOMMAP:
 419                 tdb->flags &= ~TDB_NOMMAP;
 420                 tdb_mmap(tdb);
 421                 break;
 422         case TDB_NOSYNC:
 423                 tdb->flags &= ~TDB_NOSYNC;
 424                 break;
 425         case TDB_SEQNUM:
 426                 tdb->flags &= ~TDB_SEQNUM;
 427                 break;
 428         case TDB_ALLOW_NESTING:
 429                 tdb->flags &= ~TDB_ALLOW_NESTING;
 430                 break;
 431         case TDB_RDONLY:
 432                 if ((tdb->open_flags & O_ACCMODE) == O_RDONLY) {
 433                         tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
 434                                                      TDB_LOG_USE_ERROR,
 435                                                      "tdb_remove_flag: can't"
 436                                                      " remove TDB_RDONLY on tdb"
 437                                                      " opened with O_RDONLY");
 438                         break;
 439                 }
 440                 if (readonly_changable(tdb, "tdb_remove_flag"))
 441                         tdb->flags &= ~TDB_RDONLY;
 442                 break;
 443         default:
 444                 tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
 445                                              TDB_LOG_USE_ERROR,
 446                                              "tdb_remove_flag: Unknown flag %u",
 447                                              flag);
 448         }
 449 }
 450
 451 const char *tdb_errorstr(enum TDB_ERROR ecode)
 452 {
 453         /* Gcc warns if you miss a case in the switch, so use that. */
 454         switch (ecode) {
 455         case TDB_SUCCESS: return "Success";
 456         case TDB_ERR_CORRUPT: return "Corrupt database";
 457         case TDB_ERR_IO: return "IO Error";
 458         case TDB_ERR_LOCK: return "Locking error";
 459         case TDB_ERR_OOM: return "Out of memory";
 460         case TDB_ERR_EXISTS: return "Record exists";
 461         case TDB_ERR_EINVAL: return "Invalid parameter";
 462         case TDB_ERR_NOEXIST: return "Record does not exist";
 463         case TDB_ERR_RDONLY: return "write not permitted";
 464         }
 465         return "Invalid error code";
 466 }
 467
 468 enum TDB_ERROR tdb_error(struct tdb_context *tdb)
 469 {
 470         return tdb->last_error;
 471 }
 472
 473 enum TDB_ERROR COLD tdb_logerr(struct tdb_context *tdb,
 474                                enum TDB_ERROR ecode,
 475                                enum tdb_log_level level,
 476                                const char *fmt, ...)
 477 {
 478         char *message;
 479         va_list ap;
 480         size_t len;
 481         /* tdb_open paths care about errno, so save it. */
 482         int saved_errno = errno;
 483
 484         if (!tdb->log_fn)
 485                 return ecode;
 486
 487         va_start(ap, fmt);
 488         len = vasprintf(&message, fmt, ap);
 489         va_end(ap);
 490
 491         if (len < 0) {
 492                 tdb->log_fn(tdb, TDB_LOG_ERROR, TDB_ERR_OOM,
 493                             "out of memory formatting message:", tdb->log_data);
 494                 tdb->log_fn(tdb, level, ecode, fmt, tdb->log_data);
 495         } else {
 496                 tdb->log_fn(tdb, level, ecode, message, tdb->log_data);
 497                 free(message);
 498         }
 499         errno = saved_errno;
 500         return ecode;
 501 }
 502
 503 enum TDB_ERROR tdb_parse_record_(struct tdb_context *tdb,
 504                                  TDB_DATA key,
 505                                  enum TDB_ERROR (*parse)(TDB_DATA k,
 506                                                          TDB_DATA d,
 507                                                          void *data),
 508                                  void *data)
 509 {
 510         tdb_off_t off;
 511         struct tdb_used_record rec;
 512         struct hash_info h;
 513         enum TDB_ERROR ecode;
 514
 515         off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
 516         if (TDB_OFF_IS_ERR(off)) {
 517                 return tdb->last_error = off;
 518         }
 519
 520         if (!off) {
 521                 ecode = TDB_ERR_NOEXIST;
 522         } else {
 523                 const void *dptr;
 524                 dptr = tdb_access_read(tdb, off + sizeof(rec) + key.dsize,
 525                                        rec_data_length(&rec), false);
 526                 if (TDB_PTR_IS_ERR(dptr)) {
 527                         ecode = TDB_PTR_ERR(dptr);
 528                 } else {
 529                         TDB_DATA d = tdb_mkdata(dptr, rec_data_length(&rec));
 530
 531                         ecode = parse(key, d, data);
 532                         tdb_access_release(tdb, dptr);
 533                 }
 534         }
 535
 536         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
 537         return tdb->last_error = ecode;
 538 }
 539
 540 const char *tdb_name(const struct tdb_context *tdb)
 541 {
 542         return tdb->name;
 543 }
 544
 545 int64_t tdb_get_seqnum(struct tdb_context *tdb)
 546 {
 547         tdb_off_t off = tdb_read_off(tdb, offsetof(struct tdb_header, seqnum));
 548         if (TDB_OFF_IS_ERR(off))
 549                 tdb->last_error = off;
 550         else
 551                 tdb->last_error = TDB_SUCCESS;
 552         return off;
 553 }
 554
 555
 556 int tdb_fd(const struct tdb_context *tdb)
 557 {
 558         return tdb->file->fd;
 559 }