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