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

   1 #include "private.h"
   2 #include <ccan/asprintf/asprintf.h>
   3 #include <stdarg.h>
   4
   5 static enum TDB_ERROR update_rec_hdr(struct tdb_context *tdb,
   6                                      tdb_off_t off,
   7                                      tdb_len_t keylen,
   8                                      tdb_len_t datalen,
   9                                      struct tdb_used_record *rec,
  10                                      uint64_t h)
  11 {
  12         uint64_t dataroom = rec_data_length(rec) + rec_extra_padding(rec);
  13         enum TDB_ERROR ecode;
  14
  15         ecode = set_header(tdb, rec, TDB_USED_MAGIC, keylen, datalen,
  16                            keylen + dataroom, h);
  17         if (ecode == TDB_SUCCESS) {
  18                 ecode = tdb_write_convert(tdb, off, rec, sizeof(*rec));
  19         }
  20         return ecode;
  21 }
  22
  23 static enum TDB_ERROR replace_data(struct tdb_context *tdb,
  24                                    struct hash_info *h,
  25                                    struct tdb_data key, struct tdb_data dbuf,
  26                                    tdb_off_t old_off, tdb_len_t old_room,
  27                                    bool growing)
  28 {
  29         tdb_off_t new_off;
  30         enum TDB_ERROR ecode;
  31
  32         /* Allocate a new record. */
  33         new_off = alloc(tdb, key.dsize, dbuf.dsize, h->h, TDB_USED_MAGIC,
  34                         growing);
  35         if (TDB_OFF_IS_ERR(new_off)) {
  36                 return new_off;
  37         }
  38
  39         /* We didn't like the existing one: remove it. */
  40         if (old_off) {
  41                 tdb->stats.frees++;
  42                 ecode = add_free_record(tdb, old_off,
  43                                         sizeof(struct tdb_used_record)
  44                                         + key.dsize + old_room,
  45                                         TDB_LOCK_WAIT, true);
  46                 if (ecode == TDB_SUCCESS)
  47                         ecode = replace_in_hash(tdb, h, new_off);
  48         } else {
  49                 ecode = add_to_hash(tdb, h, new_off);
  50         }
  51         if (ecode != TDB_SUCCESS) {
  52                 return ecode;
  53         }
  54
  55         new_off += sizeof(struct tdb_used_record);
  56         ecode = tdb->methods->twrite(tdb, new_off, key.dptr, key.dsize);
  57         if (ecode != TDB_SUCCESS) {
  58                 return ecode;
  59         }
  60
  61         new_off += key.dsize;
  62         ecode = tdb->methods->twrite(tdb, new_off, dbuf.dptr, dbuf.dsize);
  63         if (ecode != TDB_SUCCESS) {
  64                 return ecode;
  65         }
  66
  67         if (tdb->flags & TDB_SEQNUM)
  68                 tdb_inc_seqnum(tdb);
  69
  70         return TDB_SUCCESS;
  71 }
  72
  73 static enum TDB_ERROR update_data(struct tdb_context *tdb,
  74                                   tdb_off_t off,
  75                                   struct tdb_data dbuf,
  76                                   tdb_len_t extra)
  77 {
  78         enum TDB_ERROR ecode;
  79
  80         ecode = tdb->methods->twrite(tdb, off, dbuf.dptr, dbuf.dsize);
  81         if (ecode == TDB_SUCCESS && extra) {
  82                 /* Put a zero in; future versions may append other data. */
  83                 ecode = tdb->methods->twrite(tdb, off + dbuf.dsize, "", 1);
  84         }
  85         if (tdb->flags & TDB_SEQNUM)
  86                 tdb_inc_seqnum(tdb);
  87
  88         return ecode;
  89 }
  90
  91 enum TDB_ERROR tdb_store(struct tdb_context *tdb,
  92                          struct tdb_data key, struct tdb_data dbuf, int flag)
  93 {
  94         struct hash_info h;
  95         tdb_off_t off;
  96         tdb_len_t old_room = 0;
  97         struct tdb_used_record rec;
  98         enum TDB_ERROR ecode;
  99
 100         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 101         if (TDB_OFF_IS_ERR(off)) {
 102                 return tdb->last_error = off;
 103         }
 104
 105         /* Now we have lock on this hash bucket. */
 106         if (flag == TDB_INSERT) {
 107                 if (off) {
 108                         ecode = TDB_ERR_EXISTS;
 109                         goto out;
 110                 }
 111         } else {
 112                 if (off) {
 113                         old_room = rec_data_length(&rec)
 114                                 + rec_extra_padding(&rec);
 115                         if (old_room >= dbuf.dsize) {
 116                                 /* Can modify in-place.  Easy! */
 117                                 ecode = update_rec_hdr(tdb, off,
 118                                                        key.dsize, dbuf.dsize,
 119                                                        &rec, h.h);
 120                                 if (ecode != TDB_SUCCESS) {
 121                                         goto out;
 122                                 }
 123                                 ecode = update_data(tdb,
 124                                                     off + sizeof(rec)
 125                                                     + key.dsize, dbuf,
 126                                                     old_room - dbuf.dsize);
 127                                 if (ecode != TDB_SUCCESS) {
 128                                         goto out;
 129                                 }
 130                                 tdb_unlock_hashes(tdb, h.hlock_start,
 131                                                   h.hlock_range, F_WRLCK);
 132                                 return tdb->last_error = TDB_SUCCESS;
 133                         }
 134                 } else {
 135                         if (flag == TDB_MODIFY) {
 136                                 /* if the record doesn't exist and we
 137                                    are in TDB_MODIFY mode then we should fail
 138                                    the store */
 139                                 ecode = TDB_ERR_NOEXIST;
 140                                 goto out;
 141                         }
 142                 }
 143         }
 144
 145         /* If we didn't use the old record, this implies we're growing. */
 146         ecode = replace_data(tdb, &h, key, dbuf, off, old_room, off);
 147 out:
 148         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 149         return tdb->last_error = ecode;
 150 }
 151
 152 enum TDB_ERROR tdb_append(struct tdb_context *tdb,
 153                           struct tdb_data key, struct tdb_data dbuf)
 154 {
 155         struct hash_info h;
 156         tdb_off_t off;
 157         struct tdb_used_record rec;
 158         tdb_len_t old_room = 0, old_dlen;
 159         unsigned char *newdata;
 160         struct tdb_data new_dbuf;
 161         enum TDB_ERROR ecode;
 162
 163         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 164         if (TDB_OFF_IS_ERR(off)) {
 165                 return tdb->last_error = off;
 166         }
 167
 168         if (off) {
 169                 old_dlen = rec_data_length(&rec);
 170                 old_room = old_dlen + rec_extra_padding(&rec);
 171
 172                 /* Fast path: can append in place. */
 173                 if (rec_extra_padding(&rec) >= dbuf.dsize) {
 174                         ecode = update_rec_hdr(tdb, off, key.dsize,
 175                                                old_dlen + dbuf.dsize, &rec,
 176                                                h.h);
 177                         if (ecode != TDB_SUCCESS) {
 178                                 goto out;
 179                         }
 180
 181                         off += sizeof(rec) + key.dsize + old_dlen;
 182                         ecode = update_data(tdb, off, dbuf,
 183                                             rec_extra_padding(&rec));
 184                         goto out;
 185                 }
 186
 187                 /* Slow path. */
 188                 newdata = malloc(key.dsize + old_dlen + dbuf.dsize);
 189                 if (!newdata) {
 190                         ecode = tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
 191                                            "tdb_append:"
 192                                            " failed to allocate %zu bytes",
 193                                            (size_t)(key.dsize + old_dlen
 194                                                     + dbuf.dsize));
 195                         goto out;
 196                 }
 197                 ecode = tdb->methods->tread(tdb, off + sizeof(rec) + key.dsize,
 198                                             newdata, old_dlen);
 199                 if (ecode != TDB_SUCCESS) {
 200                         goto out_free_newdata;
 201                 }
 202                 memcpy(newdata + old_dlen, dbuf.dptr, dbuf.dsize);
 203                 new_dbuf.dptr = newdata;
 204                 new_dbuf.dsize = old_dlen + dbuf.dsize;
 205         } else {
 206                 newdata = NULL;
 207                 new_dbuf = dbuf;
 208         }
 209
 210         /* If they're using tdb_append(), it implies they're growing record. */
 211         ecode = replace_data(tdb, &h, key, new_dbuf, off, old_room, true);
 212
 213 out_free_newdata:
 214         free(newdata);
 215 out:
 216         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 217         return tdb->last_error = ecode;
 218 }
 219
 220 enum TDB_ERROR tdb_fetch(struct tdb_context *tdb, struct tdb_data key,
 221                          struct tdb_data *data)
 222 {
 223         tdb_off_t off;
 224         struct tdb_used_record rec;
 225         struct hash_info h;
 226         enum TDB_ERROR ecode;
 227
 228         off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
 229         if (TDB_OFF_IS_ERR(off)) {
 230                 return tdb->last_error = off;
 231         }
 232
 233         if (!off) {
 234                 ecode = TDB_ERR_NOEXIST;
 235         } else {
 236                 data->dsize = rec_data_length(&rec);
 237                 data->dptr = tdb_alloc_read(tdb, off + sizeof(rec) + key.dsize,
 238                                             data->dsize);
 239                 if (TDB_PTR_IS_ERR(data->dptr)) {
 240                         ecode = TDB_PTR_ERR(data->dptr);
 241                 } else
 242                         ecode = TDB_SUCCESS;
 243         }
 244
 245         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
 246         return tdb->last_error = ecode;
 247 }
 248
 249 bool tdb_exists(struct tdb_context *tdb, TDB_DATA key)
 250 {
 251         tdb_off_t off;
 252         struct tdb_used_record rec;
 253         struct hash_info h;
 254
 255         off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
 256         if (TDB_OFF_IS_ERR(off)) {
 257                 tdb->last_error = off;
 258                 return false;
 259         }
 260         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
 261
 262         tdb->last_error = TDB_SUCCESS;
 263         return off ? true : false;
 264 }
 265
 266 enum TDB_ERROR tdb_delete(struct tdb_context *tdb, struct tdb_data key)
 267 {
 268         tdb_off_t off;
 269         struct tdb_used_record rec;
 270         struct hash_info h;
 271         enum TDB_ERROR ecode;
 272
 273         off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 274         if (TDB_OFF_IS_ERR(off)) {
 275                 return tdb->last_error = off;
 276         }
 277
 278         if (!off) {
 279                 ecode = TDB_ERR_NOEXIST;
 280                 goto unlock;
 281         }
 282
 283         ecode = delete_from_hash(tdb, &h);
 284         if (ecode != TDB_SUCCESS) {
 285                 goto unlock;
 286         }
 287
 288         /* Free the deleted entry. */
 289         tdb->stats.frees++;
 290         ecode = add_free_record(tdb, off,
 291                                 sizeof(struct tdb_used_record)
 292                                 + rec_key_length(&rec)
 293                                 + rec_data_length(&rec)
 294                                 + rec_extra_padding(&rec),
 295                                 TDB_LOCK_WAIT, true);
 296
 297         if (tdb->flags & TDB_SEQNUM)
 298                 tdb_inc_seqnum(tdb);
 299
 300 unlock:
 301         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
 302         return tdb->last_error = ecode;
 303 }
 304
 305 unsigned int tdb_get_flags(struct tdb_context *tdb)
 306 {
 307         return tdb->flags;
 308 }
 309
 310 void tdb_add_flag(struct tdb_context *tdb, unsigned flag)
 311 {
 312         if (tdb->flags & TDB_INTERNAL) {
 313                 tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
 314                                              TDB_LOG_USE_ERROR,
 315                                              "tdb_add_flag: internal db");
 316                 return;
 317         }
 318         switch (flag) {
 319         case TDB_NOLOCK:
 320                 tdb->flags |= TDB_NOLOCK;
 321                 break;
 322         case TDB_NOMMAP:
 323                 tdb->flags |= TDB_NOMMAP;
 324                 tdb_munmap(tdb->file);
 325                 break;
 326         case TDB_NOSYNC:
 327                 tdb->flags |= TDB_NOSYNC;
 328                 break;
 329         case TDB_SEQNUM:
 330                 tdb->flags |= TDB_SEQNUM;
 331                 break;
 332         case TDB_ALLOW_NESTING:
 333                 tdb->flags |= TDB_ALLOW_NESTING;
 334                 break;
 335         default:
 336                 tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
 337                                              TDB_LOG_USE_ERROR,
 338                                              "tdb_add_flag: Unknown flag %u",
 339                                              flag);
 340         }
 341 }
 342
 343 void tdb_remove_flag(struct tdb_context *tdb, unsigned flag)
 344 {
 345         if (tdb->flags & TDB_INTERNAL) {
 346                 tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
 347                                              TDB_LOG_USE_ERROR,
 348                                              "tdb_remove_flag: internal db");
 349                 return;
 350         }
 351         switch (flag) {
 352         case TDB_NOLOCK:
 353                 tdb->flags &= ~TDB_NOLOCK;
 354                 break;
 355         case TDB_NOMMAP:
 356                 tdb->flags &= ~TDB_NOMMAP;
 357                 tdb_mmap(tdb);
 358                 break;
 359         case TDB_NOSYNC:
 360                 tdb->flags &= ~TDB_NOSYNC;
 361                 break;
 362         case TDB_SEQNUM:
 363                 tdb->flags &= ~TDB_SEQNUM;
 364                 break;
 365         case TDB_ALLOW_NESTING:
 366                 tdb->flags &= ~TDB_ALLOW_NESTING;
 367                 break;
 368         default:
 369                 tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
 370                                              TDB_LOG_USE_ERROR,
 371                                              "tdb_remove_flag: Unknown flag %u",
 372                                              flag);
 373         }
 374 }
 375
 376 const char *tdb_errorstr(enum TDB_ERROR ecode)
 377 {
 378         /* Gcc warns if you miss a case in the switch, so use that. */
 379         switch (ecode) {
 380         case TDB_SUCCESS: return "Success";
 381         case TDB_ERR_CORRUPT: return "Corrupt database";
 382         case TDB_ERR_IO: return "IO Error";
 383         case TDB_ERR_LOCK: return "Locking error";
 384         case TDB_ERR_OOM: return "Out of memory";
 385         case TDB_ERR_EXISTS: return "Record exists";
 386         case TDB_ERR_EINVAL: return "Invalid parameter";
 387         case TDB_ERR_NOEXIST: return "Record does not exist";
 388         case TDB_ERR_RDONLY: return "write not permitted";
 389         }
 390         return "Invalid error code";
 391 }
 392
 393 enum TDB_ERROR tdb_error(struct tdb_context *tdb)
 394 {
 395         return tdb->last_error;
 396 }
 397
 398 enum TDB_ERROR COLD tdb_logerr(struct tdb_context *tdb,
 399                                enum TDB_ERROR ecode,
 400                                enum tdb_log_level level,
 401                                const char *fmt, ...)
 402 {
 403         char *message;
 404         va_list ap;
 405         size_t len;
 406         /* tdb_open paths care about errno, so save it. */
 407         int saved_errno = errno;
 408
 409         if (!tdb->log_fn)
 410                 return ecode;
 411
 412         va_start(ap, fmt);
 413         len = vasprintf(&message, fmt, ap);
 414         va_end(ap);
 415
 416         if (len < 0) {
 417                 tdb->log_fn(tdb, TDB_LOG_ERROR,
 418                             "out of memory formatting message:", tdb->log_data);
 419                 tdb->log_fn(tdb, level, fmt, tdb->log_data);
 420         } else {
 421                 tdb->log_fn(tdb, level, message, tdb->log_data);
 422                 free(message);
 423         }
 424         errno = saved_errno;
 425         return ecode;
 426 }
 427
 428 enum TDB_ERROR tdb_parse_record_(struct tdb_context *tdb,
 429                                  TDB_DATA key,
 430                                  enum TDB_ERROR (*parse)(TDB_DATA k,
 431                                                          TDB_DATA d,
 432                                                          void *data),
 433                                  void *data)
 434 {
 435         tdb_off_t off;
 436         struct tdb_used_record rec;
 437         struct hash_info h;
 438         enum TDB_ERROR ecode;
 439
 440         off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
 441         if (TDB_OFF_IS_ERR(off)) {
 442                 return tdb->last_error = off;
 443         }
 444
 445         if (!off) {
 446                 ecode = TDB_ERR_NOEXIST;
 447         } else {
 448                 const void *dptr;
 449                 dptr = tdb_access_read(tdb, off + sizeof(rec) + key.dsize,
 450                                        rec_data_length(&rec), false);
 451                 if (TDB_PTR_IS_ERR(dptr)) {
 452                         ecode = TDB_PTR_ERR(dptr);
 453                 } else {
 454                         TDB_DATA d = tdb_mkdata(dptr, rec_data_length(&rec));
 455
 456                         ecode = parse(key, d, data);
 457                         tdb_access_release(tdb, dptr);
 458                 }
 459         }
 460
 461         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
 462         return tdb->last_error = ecode;
 463 }
 464
 465 const char *tdb_name(const struct tdb_context *tdb)
 466 {
 467         return tdb->name;
 468 }
 469
 470 int64_t tdb_get_seqnum(struct tdb_context *tdb)
 471 {
 472         tdb_off_t off = tdb_read_off(tdb, offsetof(struct tdb_header, seqnum));
 473         if (TDB_OFF_IS_ERR(off))
 474                 tdb->last_error = off;
 475         else
 476                 tdb->last_error = TDB_SUCCESS;
 477         return off;
 478 }
 479
 480
 481 int tdb_fd(const struct tdb_context *tdb)
 482 {
 483         return tdb->file->fd;
 484 }