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