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