usr.sbin/nscd/cachelib.c

   1 /*-
   2  * Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  */
  27
  28 #include <sys/cdefs.h>
  29 __FBSDID("$FreeBSD$");
  30
  31 #include <sys/time.h>
  32 #include <assert.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include "cachelib.h"
  36 #include "debug.h"
  37
  38 #define INITIAL_ENTRIES_CAPACITY 32
  39 #define ENTRIES_CAPACITY_STEP 32
  40
  41 #define STRING_SIMPLE_HASH_BODY(in_var, var, a, M)              \
  42         for ((var) = 0; *(in_var) != '\0'; ++(in_var))          \
  43                 (var) = ((a)*(var) + *(in_var)) % (M)
  44
  45 #define STRING_SIMPLE_MP2_HASH_BODY(in_var, var, a, M)          \
  46         for ((var) = 0; *(in_var) != 0; ++(in_var))             \
  47                 (var) = ((a)*(var) + *(in_var)) & (M - 1)
  48
  49 static int cache_elemsize_common_continue_func(struct cache_common_entry_ *,
  50         struct cache_policy_item_ *);
  51 static int cache_lifetime_common_continue_func(struct cache_common_entry_ *,
  52         struct cache_policy_item_ *);
  53 static void clear_cache_entry(struct cache_entry_ *);
  54 static void destroy_cache_entry(struct cache_entry_ *);
  55 static void destroy_cache_mp_read_session(struct cache_mp_read_session_ *);
  56 static void destroy_cache_mp_write_session(struct cache_mp_write_session_ *);
  57 static int entries_bsearch_cmp_func(const void *, const void *);
  58 static int entries_qsort_cmp_func(const void *, const void *);
  59 static struct cache_entry_ ** find_cache_entry_p(struct cache_ *,
  60         const char *);
  61 static void flush_cache_entry(struct cache_entry_ *);
  62 static void flush_cache_policy(struct cache_common_entry_ *,
  63         struct cache_policy_ *, struct cache_policy_ *,
  64                 int (*)(struct cache_common_entry_ *,
  65                 struct cache_policy_item_ *));
  66 static int ht_items_cmp_func(const void *, const void *);
  67 static int ht_items_fixed_size_left_cmp_func(const void *, const void *);
  68 static hashtable_index_t ht_item_hash_func(const void *, size_t);
  69
  70 /*
  71  * Hashing and comparing routines, that are used with the hash tables
  72  */
  73 static int
  74 ht_items_cmp_func(const void *p1, const void *p2)
  75 {
  76         struct cache_ht_item_data_ *hp1, *hp2;
  77         size_t min_size;
  78         int result;
  79
  80         hp1 = (struct cache_ht_item_data_ *)p1;
  81         hp2 = (struct cache_ht_item_data_ *)p2;
  82
  83         assert(hp1->key != NULL);
  84         assert(hp2->key != NULL);
  85
  86         if (hp1->key_size != hp2->key_size) {
  87                 min_size = (hp1->key_size < hp2->key_size) ? hp1->key_size :
  88                         hp2->key_size;
  89                 result = memcmp(hp1->key, hp2->key, min_size);
  90
  91                 if (result == 0)
  92                         return ((hp1->key_size < hp2->key_size) ? -1 : 1);
  93                 else
  94                         return (result);
  95         } else
  96                 return (memcmp(hp1->key, hp2->key, hp1->key_size));
  97 }
  98
  99 static int
 100 ht_items_fixed_size_left_cmp_func(const void *p1, const void *p2)
 101 {
 102         struct cache_ht_item_data_ *hp1, *hp2;
 103         size_t min_size;
 104         int result;
 105
 106         hp1 = (struct cache_ht_item_data_ *)p1;
 107         hp2 = (struct cache_ht_item_data_ *)p2;
 108
 109         assert(hp1->key != NULL);
 110         assert(hp2->key != NULL);
 111
 112         if (hp1->key_size != hp2->key_size) {
 113                 min_size = (hp1->key_size < hp2->key_size) ? hp1->key_size :
 114                         hp2->key_size;
 115                 result = memcmp(hp1->key, hp2->key, min_size);
 116
 117                 if (result == 0)
 118                         if (min_size == hp1->key_size)
 119                             return (0);
 120                         else
 121                             return ((hp1->key_size < hp2->key_size) ? -1 : 1);
 122                 else
 123                         return (result);
 124         } else
 125                 return (memcmp(hp1->key, hp2->key, hp1->key_size));
 126 }
 127
 128 static hashtable_index_t
 129 ht_item_hash_func(const void *p, size_t cache_entries_size)
 130 {
 131         struct cache_ht_item_data_ *hp;
 132         size_t i;
 133
 134         hashtable_index_t retval;
 135
 136         hp = (struct cache_ht_item_data_ *)p;
 137         assert(hp->key != NULL);
 138
 139         retval = 0;
 140         for (i = 0; i < hp->key_size; ++i)
 141             retval = (127 * retval + (unsigned char)hp->key[i]) %
 142                 cache_entries_size;
 143
 144         return retval;
 145 }
 146
 147 HASHTABLE_GENERATE(cache_ht_, cache_ht_item_, struct cache_ht_item_data_, data,
 148         ht_item_hash_func, ht_items_cmp_func);
 149
 150 /*
 151  * Routines to sort and search the entries by name
 152  */
 153 static int
 154 entries_bsearch_cmp_func(const void *key, const void *ent)
 155 {
 156
 157         assert(key != NULL);
 158         assert(ent != NULL);
 159
 160         return (strcmp((char const *)key,
 161                 (*(struct cache_entry_ const **)ent)->name));
 162 }
 163
 164 static int
 165 entries_qsort_cmp_func(const void *e1, const void *e2)
 166 {
 167
 168         assert(e1 != NULL);
 169         assert(e2 != NULL);
 170
 171         return (strcmp((*(struct cache_entry_ const **)e1)->name,
 172                 (*(struct cache_entry_ const **)e2)->name));
 173 }
 174
 175 static struct cache_entry_ **
 176 find_cache_entry_p(struct cache_ *the_cache, const char *entry_name)
 177 {
 178
 179         return ((struct cache_entry_ **)(bsearch(entry_name, the_cache->entries,
 180                 the_cache->entries_size, sizeof(struct cache_entry_ *),
 181                 entries_bsearch_cmp_func)));
 182 }
 183
 184 static void
 185 destroy_cache_mp_write_session(struct cache_mp_write_session_ *ws)
 186 {
 187
 188         struct cache_mp_data_item_      *data_item;
 189
 190         TRACE_IN(destroy_cache_mp_write_session);
 191         assert(ws != NULL);
 192         while (!TAILQ_EMPTY(&ws->items)) {
 193                 data_item = TAILQ_FIRST(&ws->items);
 194                 TAILQ_REMOVE(&ws->items, data_item, entries);
 195                 free(data_item->value);
 196                 free(data_item);
 197         }
 198
 199         free(ws);
 200         TRACE_OUT(destroy_cache_mp_write_session);
 201 }
 202
 203 static void
 204 destroy_cache_mp_read_session(struct cache_mp_read_session_ *rs)
 205 {
 206
 207         TRACE_IN(destroy_cache_mp_read_session);
 208         assert(rs != NULL);
 209         free(rs);
 210         TRACE_OUT(destroy_cache_mp_read_session);
 211 }
 212
 213 static void
 214 destroy_cache_entry(struct cache_entry_ *entry)
 215 {
 216         struct cache_common_entry_      *common_entry;
 217         struct cache_mp_entry_          *mp_entry;
 218         struct cache_mp_read_session_   *rs;
 219         struct cache_mp_write_session_  *ws;
 220         struct cache_ht_item_ *ht_item;
 221         struct cache_ht_item_data_ *ht_item_data;
 222
 223         TRACE_IN(destroy_cache_entry);
 224         assert(entry != NULL);
 225
 226         if (entry->params->entry_type == CET_COMMON) {
 227                 common_entry = (struct cache_common_entry_ *)entry;
 228
 229                 HASHTABLE_FOREACH(&(common_entry->items), ht_item) {
 230                         HASHTABLE_ENTRY_FOREACH(ht_item, data, ht_item_data)
 231                         {
 232                                 free(ht_item_data->key);
 233                                 free(ht_item_data->value);
 234                         }
 235                         HASHTABLE_ENTRY_CLEAR(ht_item, data);
 236                 }
 237
 238                 HASHTABLE_DESTROY(&(common_entry->items), data);
 239
 240                 /* FIFO policy is always first */
 241                 destroy_cache_fifo_policy(common_entry->policies[0]);
 242                 switch (common_entry->common_params.policy) {
 243                 case CPT_LRU:
 244                         destroy_cache_lru_policy(common_entry->policies[1]);
 245                         break;
 246                 case CPT_LFU:
 247                         destroy_cache_lfu_policy(common_entry->policies[1]);
 248                         break;
 249                 default:
 250                 break;
 251                 }
 252                 free(common_entry->policies);
 253         } else {
 254                 mp_entry = (struct cache_mp_entry_ *)entry;
 255
 256                 while (!TAILQ_EMPTY(&mp_entry->ws_head)) {
 257                         ws = TAILQ_FIRST(&mp_entry->ws_head);
 258                         TAILQ_REMOVE(&mp_entry->ws_head, ws, entries);
 259                         destroy_cache_mp_write_session(ws);
 260                 }
 261
 262                 while (!TAILQ_EMPTY(&mp_entry->rs_head)) {
 263                         rs = TAILQ_FIRST(&mp_entry->rs_head);
 264                         TAILQ_REMOVE(&mp_entry->rs_head, rs, entries);
 265                         destroy_cache_mp_read_session(rs);
 266                 }
 267
 268                 if (mp_entry->completed_write_session != NULL)
 269                         destroy_cache_mp_write_session(
 270                                 mp_entry->completed_write_session);
 271
 272                 if (mp_entry->pending_write_session != NULL)
 273                         destroy_cache_mp_write_session(
 274                                 mp_entry->pending_write_session);
 275         }
 276
 277         free(entry->name);
 278         free(entry);
 279         TRACE_OUT(destroy_cache_entry);
 280 }
 281
 282 static void
 283 clear_cache_entry(struct cache_entry_ *entry)
 284 {
 285         struct cache_mp_entry_          *mp_entry;
 286         struct cache_common_entry_      *common_entry;
 287         struct cache_ht_item_ *ht_item;
 288         struct cache_ht_item_data_ *ht_item_data;
 289         struct cache_policy_ *policy;
 290         struct cache_policy_item_ *item, *next_item;
 291         size_t entry_size;
 292         int i;
 293
 294         if (entry->params->entry_type == CET_COMMON) {
 295                 common_entry = (struct cache_common_entry_ *)entry;
 296
 297                 entry_size = 0;
 298                 HASHTABLE_FOREACH(&(common_entry->items), ht_item) {
 299                         HASHTABLE_ENTRY_FOREACH(ht_item, data, ht_item_data)
 300                         {
 301                                 free(ht_item_data->key);
 302                                 free(ht_item_data->value);
 303                         }
 304                         entry_size += HASHTABLE_ENTRY_SIZE(ht_item, data);
 305                         HASHTABLE_ENTRY_CLEAR(ht_item, data);
 306                 }
 307
 308                 common_entry->items_size -= entry_size;
 309                 for (i = 0; i < common_entry->policies_size; ++i) {
 310                         policy = common_entry->policies[i];
 311
 312                         next_item = NULL;
 313                         item = policy->get_first_item_func(policy);
 314                         while (item != NULL) {
 315                                 next_item = policy->get_next_item_func(policy,
 316                                         item);
 317                                 policy->remove_item_func(policy, item);
 318                                 policy->destroy_item_func(item);
 319                                 item = next_item;
 320                         }
 321                 }
 322         } else {
 323                 mp_entry = (struct cache_mp_entry_ *)entry;
 324
 325                 if (mp_entry->rs_size == 0) {
 326                         if (mp_entry->completed_write_session != NULL) {
 327                                 destroy_cache_mp_write_session(
 328                                         mp_entry->completed_write_session);
 329                                 mp_entry->completed_write_session = NULL;
 330                         }
 331
 332                         memset(&mp_entry->creation_time, 0,
 333                                 sizeof(struct timeval));
 334                         memset(&mp_entry->last_request_time, 0,
 335                                 sizeof(struct timeval));
 336                 }
 337         }
 338 }
 339
 340 /*
 341  * When passed to the flush_cache_policy, ensures that all old elements are
 342  * deleted.
 343  */
 344 static int
 345 cache_lifetime_common_continue_func(struct cache_common_entry_ *entry,
 346         struct cache_policy_item_ *item)
 347 {
 348
 349         return ((item->last_request_time.tv_sec - item->creation_time.tv_sec >
 350                 entry->common_params.max_lifetime.tv_sec) ? 1: 0);
 351 }
 352
 353 /*
 354  * When passed to the flush_cache_policy, ensures that all elements, that
 355  * exceed the size limit, are deleted.
 356  */
 357 static int
 358 cache_elemsize_common_continue_func(struct cache_common_entry_ *entry,
 359         struct cache_policy_item_ *item)
 360 {
 361
 362         return ((entry->items_size > entry->common_params.satisf_elemsize) ? 1
 363                 : 0);
 364 }
 365
 366 /*
 367  * Removes the elements from the cache entry, while the continue_func returns 1.
 368  */
 369 static void
 370 flush_cache_policy(struct cache_common_entry_ *entry,
 371         struct cache_policy_ *policy,
 372         struct cache_policy_ *connected_policy,
 373         int (*continue_func)(struct cache_common_entry_ *,
 374                 struct cache_policy_item_ *))
 375 {
 376         struct cache_policy_item_ *item, *next_item, *connected_item;
 377         struct cache_ht_item_ *ht_item;
 378         struct cache_ht_item_data_ *ht_item_data, ht_key;
 379         hashtable_index_t hash;
 380
 381         assert(policy != NULL);
 382
 383         next_item = NULL;
 384         item = policy->get_first_item_func(policy);
 385         while ((item != NULL) && (continue_func(entry, item) == 1)) {
 386                 next_item = policy->get_next_item_func(policy, item);
 387
 388                 connected_item = item->connected_item;
 389                 policy->remove_item_func(policy, item);
 390
 391                 memset(&ht_key, 0, sizeof(struct cache_ht_item_data_));
 392                 ht_key.key = item->key;
 393                 ht_key.key_size = item->key_size;
 394
 395                 hash = HASHTABLE_CALCULATE_HASH(cache_ht_, &entry->items,
 396                         &ht_key);
 397                 assert(hash >= 0);
 398                 assert(hash < HASHTABLE_ENTRIES_COUNT(&entry->items));
 399
 400                 ht_item = HASHTABLE_GET_ENTRY(&(entry->items), hash);
 401                 ht_item_data = HASHTABLE_ENTRY_FIND(cache_ht_, ht_item,
 402                         &ht_key);
 403                 assert(ht_item_data != NULL);
 404                 free(ht_item_data->key);
 405                 free(ht_item_data->value);
 406                 HASHTABLE_ENTRY_REMOVE(cache_ht_, ht_item, ht_item_data);
 407                 --entry->items_size;
 408
 409                 policy->destroy_item_func(item);
 410
 411                 if (connected_item != NULL) {
 412                         connected_policy->remove_item_func(connected_policy,
 413                                 connected_item);
 414                         connected_policy->destroy_item_func(connected_item);
 415                 }
 416
 417                 item = next_item;
 418         }
 419 }
 420
 421 static void
 422 flush_cache_entry(struct cache_entry_ *entry)
 423 {
 424         struct cache_mp_entry_          *mp_entry;
 425         struct cache_common_entry_      *common_entry;
 426         struct cache_policy_ *policy, *connected_policy;
 427
 428         connected_policy = NULL;
 429         if (entry->params->entry_type == CET_COMMON) {
 430                 common_entry = (struct cache_common_entry_ *)entry;
 431                 if ((common_entry->common_params.max_lifetime.tv_sec != 0) ||
 432                     (common_entry->common_params.max_lifetime.tv_usec != 0)) {
 433
 434                         policy = common_entry->policies[0];
 435                         if (common_entry->policies_size > 1)
 436                                 connected_policy = common_entry->policies[1];
 437
 438                         flush_cache_policy(common_entry, policy,
 439                                 connected_policy,
 440                                 cache_lifetime_common_continue_func);
 441                 }
 442
 443
 444                 if ((common_entry->common_params.max_elemsize != 0) &&
 445                         common_entry->items_size >
 446                         common_entry->common_params.max_elemsize) {
 447
 448                         if (common_entry->policies_size > 1) {
 449                                 policy = common_entry->policies[1];
 450                                 connected_policy = common_entry->policies[0];
 451                         } else {
 452                                 policy = common_entry->policies[0];
 453                                 connected_policy = NULL;
 454                         }
 455
 456                         flush_cache_policy(common_entry, policy,
 457                                 connected_policy,
 458                                 cache_elemsize_common_continue_func);
 459                 }
 460         } else {
 461                 mp_entry = (struct cache_mp_entry_ *)entry;
 462
 463                 if ((mp_entry->mp_params.max_lifetime.tv_sec != 0)
 464                         || (mp_entry->mp_params.max_lifetime.tv_usec != 0)) {
 465
 466                         if (mp_entry->last_request_time.tv_sec -
 467                                 mp_entry->last_request_time.tv_sec >
 468                                 mp_entry->mp_params.max_lifetime.tv_sec)
 469                                 clear_cache_entry(entry);
 470                 }
 471         }
 472 }
 473
 474 struct cache_ *
 475 init_cache(struct cache_params const *params)
 476 {
 477         struct cache_ *retval;
 478
 479         TRACE_IN(init_cache);
 480         assert(params != NULL);
 481
 482         retval = (struct cache_ *)calloc(1, sizeof(struct cache_));
 483         assert(retval != NULL);
 484
 485         assert(params != NULL);
 486         memcpy(&retval->params, params, sizeof(struct cache_params));
 487
 488         retval->entries = (struct cache_entry_ **)calloc(1,
 489                 sizeof(struct cache_entry_ *) * INITIAL_ENTRIES_CAPACITY);
 490         assert(retval->entries != NULL);
 491
 492         retval->entries_capacity = INITIAL_ENTRIES_CAPACITY;
 493         retval->entries_size = 0;
 494
 495         TRACE_OUT(init_cache);
 496         return (retval);
 497 }
 498
 499 void
 500 destroy_cache(struct cache_ *the_cache)
 501 {
 502
 503         TRACE_IN(destroy_cache);
 504         assert(the_cache != NULL);
 505
 506         if (the_cache->entries != NULL) {
 507                 size_t i;
 508                 for (i = 0; i < the_cache->entries_size; ++i)
 509                         destroy_cache_entry(the_cache->entries[i]);
 510
 511                 free(the_cache->entries);
 512         }
 513
 514         free(the_cache);
 515         TRACE_OUT(destroy_cache);
 516 }
 517
 518 int
 519 register_cache_entry(struct cache_ *the_cache,
 520         struct cache_entry_params const *params)
 521 {
 522         int policies_size;
 523         size_t entry_name_size;
 524         struct cache_common_entry_      *new_common_entry;
 525         struct cache_mp_entry_          *new_mp_entry;
 526
 527         TRACE_IN(register_cache_entry);
 528         assert(the_cache != NULL);
 529
 530         if (find_cache_entry(the_cache, params->entry_name) != NULL) {
 531                 TRACE_OUT(register_cache_entry);
 532                 return (-1);
 533         }
 534
 535         if (the_cache->entries_size == the_cache->entries_capacity) {
 536                 struct cache_entry_ **new_entries;
 537                 size_t  new_capacity;
 538
 539                 new_capacity = the_cache->entries_capacity +
 540                         ENTRIES_CAPACITY_STEP;
 541                 new_entries = (struct cache_entry_ **)calloc(1,
 542                         sizeof(struct cache_entry_ *) * new_capacity);
 543                 assert(new_entries != NULL);
 544
 545                 memcpy(new_entries, the_cache->entries,
 546                         sizeof(struct cache_entry_ *)
 547                         * the_cache->entries_size);
 548
 549                 free(the_cache->entries);
 550                 the_cache->entries = new_entries;
 551         }
 552
 553         entry_name_size = strlen(params->entry_name) + 1;
 554         switch (params->entry_type)
 555         {
 556         case CET_COMMON:
 557                 new_common_entry = (struct cache_common_entry_ *)calloc(1,
 558                         sizeof(struct cache_common_entry_));
 559                 assert(new_common_entry != NULL);
 560
 561                 memcpy(&new_common_entry->common_params, params,
 562                         sizeof(struct common_cache_entry_params));
 563                 new_common_entry->params =
 564                   (struct cache_entry_params *)&new_common_entry->common_params;
 565
 566                 new_common_entry->common_params.entry_name = (char *)calloc(1,
 567                         entry_name_size);
 568                 assert(new_common_entry->common_params.entry_name != NULL);
 569                 strlcpy(new_common_entry->common_params.entry_name,
 570                         params->entry_name, entry_name_size);
 571                 new_common_entry->name =
 572                         new_common_entry->common_params.entry_name;
 573
 574                 HASHTABLE_INIT(&(new_common_entry->items),
 575                         struct cache_ht_item_data_, data,
 576                         new_common_entry->common_params.cache_entries_size);
 577
 578                 if (new_common_entry->common_params.policy == CPT_FIFO)
 579                         policies_size = 1;
 580                 else
 581                         policies_size = 2;
 582
 583                 new_common_entry->policies = (struct cache_policy_ **)calloc(1,
 584                         sizeof(struct cache_policy_ *) * policies_size);
 585                 assert(new_common_entry->policies != NULL);
 586
 587                 new_common_entry->policies_size = policies_size;
 588                 new_common_entry->policies[0] = init_cache_fifo_policy();
 589
 590                 if (policies_size > 1) {
 591                         switch (new_common_entry->common_params.policy) {
 592                         case CPT_LRU:
 593                                 new_common_entry->policies[1] =
 594                                         init_cache_lru_policy();
 595                         break;
 596                         case CPT_LFU:
 597                                 new_common_entry->policies[1] =
 598                                         init_cache_lfu_policy();
 599                         break;
 600                         default:
 601                         break;
 602                         }
 603                 }
 604
 605                 new_common_entry->get_time_func =
 606                         the_cache->params.get_time_func;
 607                 the_cache->entries[the_cache->entries_size++] =
 608                         (struct cache_entry_ *)new_common_entry;
 609                 break;
 610         case CET_MULTIPART:
 611                 new_mp_entry = (struct cache_mp_entry_ *)calloc(1,
 612                         sizeof(struct cache_mp_entry_));
 613                 assert(new_mp_entry != NULL);
 614
 615                 memcpy(&new_mp_entry->mp_params, params,
 616                         sizeof(struct mp_cache_entry_params));
 617                 new_mp_entry->params =
 618                         (struct cache_entry_params *)&new_mp_entry->mp_params;
 619
 620                 new_mp_entry->mp_params.entry_name = (char *)calloc(1,
 621                         entry_name_size);
 622                 assert(new_mp_entry->mp_params.entry_name != NULL);
 623                 strlcpy(new_mp_entry->mp_params.entry_name, params->entry_name,
 624                         entry_name_size);
 625                 new_mp_entry->name = new_mp_entry->mp_params.entry_name;
 626
 627                 TAILQ_INIT(&new_mp_entry->ws_head);
 628                 TAILQ_INIT(&new_mp_entry->rs_head);
 629
 630                 new_mp_entry->get_time_func = the_cache->params.get_time_func;
 631                 the_cache->entries[the_cache->entries_size++] =
 632                         (struct cache_entry_ *)new_mp_entry;
 633                 break;
 634         }
 635
 636
 637         qsort(the_cache->entries, the_cache->entries_size,
 638                 sizeof(struct cache_entry_ *), entries_qsort_cmp_func);
 639
 640         TRACE_OUT(register_cache_entry);
 641         return (0);
 642 }
 643
 644 int
 645 unregister_cache_entry(struct cache_ *the_cache, const char *entry_name)
 646 {
 647         struct cache_entry_ **del_ent;
 648
 649         TRACE_IN(unregister_cache_entry);
 650         assert(the_cache != NULL);
 651
 652         del_ent = find_cache_entry_p(the_cache, entry_name);
 653         if (del_ent != NULL) {
 654                 destroy_cache_entry(*del_ent);
 655                 --the_cache->entries_size;
 656
 657                 memmove(del_ent, del_ent + 1,
 658                         (&(the_cache->entries[--the_cache->entries_size]) -
 659                         del_ent) * sizeof(struct cache_entry_ *));
 660
 661                 TRACE_OUT(unregister_cache_entry);
 662                 return (0);
 663         } else {
 664                 TRACE_OUT(unregister_cache_entry);
 665                 return (-1);
 666         }
 667 }
 668
 669 struct cache_entry_ *
 670 find_cache_entry(struct cache_ *the_cache, const char *entry_name)
 671 {
 672         struct cache_entry_ **result;
 673
 674         TRACE_IN(find_cache_entry);
 675         result = find_cache_entry_p(the_cache, entry_name);
 676
 677         if (result == NULL) {
 678                 TRACE_OUT(find_cache_entry);
 679                 return (NULL);
 680         } else {
 681                 TRACE_OUT(find_cache_entry);
 682                 return (*result);
 683         }
 684 }
 685
 686 /*
 687  * Tries to read the element with the specified key from the cache. If the
 688  * value_size is too small, it will be filled with the proper number, and
 689  * the user will need to call cache_read again with the value buffer, that
 690  * is large enough.
 691  * Function returns 0 on success, -1 on error, and -2 if the value_size is too
 692  * small.
 693  */
 694 int
 695 cache_read(struct cache_entry_ *entry, const char *key, size_t key_size,
 696         char *value, size_t *value_size)
 697 {
 698         struct cache_common_entry_      *common_entry;
 699         struct cache_ht_item_data_      item_data, *find_res;
 700         struct cache_ht_item_           *item;
 701         hashtable_index_t       hash;
 702         struct cache_policy_item_ *connected_item;
 703
 704         TRACE_IN(cache_read);
 705         assert(entry != NULL);
 706         assert(key != NULL);
 707         assert(value_size != NULL);
 708         assert(entry->params->entry_type == CET_COMMON);
 709
 710         common_entry = (struct cache_common_entry_ *)entry;
 711
 712         memset(&item_data, 0, sizeof(struct cache_ht_item_data_));
 713         /* can't avoid the cast here */
 714         item_data.key = (char *)key;
 715         item_data.key_size = key_size;
 716
 717         hash = HASHTABLE_CALCULATE_HASH(cache_ht_, &common_entry->items,
 718                 &item_data);
 719         assert(hash >= 0);
 720         assert(hash < HASHTABLE_ENTRIES_COUNT(&common_entry->items));
 721
 722         item = HASHTABLE_GET_ENTRY(&(common_entry->items), hash);
 723         find_res = HASHTABLE_ENTRY_FIND(cache_ht_, item, &item_data);
 724         if (find_res == NULL) {
 725                 TRACE_OUT(cache_read);
 726                 return (-1);
 727         }
 728
 729         if ((common_entry->common_params.max_lifetime.tv_sec != 0) ||
 730                 (common_entry->common_params.max_lifetime.tv_usec != 0)) {
 731
 732                 if (find_res->fifo_policy_item->last_request_time.tv_sec -
 733                         find_res->fifo_policy_item->creation_time.tv_sec >
 734                         common_entry->common_params.max_lifetime.tv_sec) {
 735
 736                         free(find_res->key);
 737                         free(find_res->value);
 738
 739                         connected_item =
 740                             find_res->fifo_policy_item->connected_item;
 741                         if (connected_item != NULL) {
 742                                 common_entry->policies[1]->remove_item_func(
 743                                         common_entry->policies[1],
 744                                         connected_item);
 745                                 common_entry->policies[1]->destroy_item_func(
 746                                         connected_item);
 747                         }
 748
 749                         common_entry->policies[0]->remove_item_func(
 750                                 common_entry->policies[0],
 751                                         find_res->fifo_policy_item);
 752                         common_entry->policies[0]->destroy_item_func(
 753                                 find_res->fifo_policy_item);
 754
 755                         HASHTABLE_ENTRY_REMOVE(cache_ht_, item, find_res);
 756                         --common_entry->items_size;
 757                 }
 758         }
 759
 760         if ((*value_size < find_res->value_size) || (value == NULL)) {
 761                 *value_size = find_res->value_size;
 762                 TRACE_OUT(cache_read);
 763                 return (-2);
 764         }
 765
 766         *value_size = find_res->value_size;
 767         memcpy(value, find_res->value, find_res->value_size);
 768
 769         ++find_res->fifo_policy_item->request_count;
 770         common_entry->get_time_func(
 771                 &find_res->fifo_policy_item->last_request_time);
 772         common_entry->policies[0]->update_item_func(common_entry->policies[0],
 773                 find_res->fifo_policy_item);
 774
 775         if (find_res->fifo_policy_item->connected_item != NULL) {
 776                 connected_item = find_res->fifo_policy_item->connected_item;
 777                 memcpy(&connected_item->last_request_time,
 778                         &find_res->fifo_policy_item->last_request_time,
 779                         sizeof(struct timeval));
 780                 connected_item->request_count =
 781                         find_res->fifo_policy_item->request_count;
 782
 783                 common_entry->policies[1]->update_item_func(
 784                         common_entry->policies[1], connected_item);
 785         }
 786
 787         TRACE_OUT(cache_read);
 788         return (0);
 789 }
 790
 791 /*
 792  * Writes the value with the specified key into the cache entry.
 793  * Functions returns 0 on success, and -1 on error.
 794  */
 795 int
 796 cache_write(struct cache_entry_ *entry, const char *key, size_t key_size,
 797         char const *value, size_t value_size)
 798 {
 799         struct cache_common_entry_      *common_entry;
 800         struct cache_ht_item_data_      item_data, *find_res;
 801         struct cache_ht_item_           *item;
 802         hashtable_index_t       hash;
 803
 804         struct cache_policy_            *policy, *connected_policy;
 805         struct cache_policy_item_       *policy_item;
 806         struct cache_policy_item_       *connected_policy_item;
 807
 808         TRACE_IN(cache_write);
 809         assert(entry != NULL);
 810         assert(key != NULL);
 811         assert(value != NULL);
 812         assert(entry->params->entry_type == CET_COMMON);
 813
 814         common_entry = (struct cache_common_entry_ *)entry;
 815
 816         memset(&item_data, 0, sizeof(struct cache_ht_item_data_));
 817         /* can't avoid the cast here */
 818         item_data.key = (char *)key;
 819         item_data.key_size = key_size;
 820
 821         hash = HASHTABLE_CALCULATE_HASH(cache_ht_, &common_entry->items,
 822                 &item_data);
 823         assert(hash >= 0);
 824         assert(hash < HASHTABLE_ENTRIES_COUNT(&common_entry->items));
 825
 826         item = HASHTABLE_GET_ENTRY(&(common_entry->items), hash);
 827         find_res = HASHTABLE_ENTRY_FIND(cache_ht_, item, &item_data);
 828         if (find_res != NULL) {
 829                 TRACE_OUT(cache_write);
 830                 return (-1);
 831         }
 832
 833         item_data.key = (char *)malloc(key_size);
 834         memcpy(item_data.key, key, key_size);
 835
 836         item_data.value = (char *)malloc(value_size);
 837         assert(item_data.value != NULL);
 838
 839         memcpy(item_data.value, value, value_size);
 840         item_data.value_size = value_size;
 841
 842         policy_item = common_entry->policies[0]->create_item_func();
 843         policy_item->key = item_data.key;
 844         policy_item->key_size = item_data.key_size;
 845         common_entry->get_time_func(&policy_item->creation_time);
 846
 847         if (common_entry->policies_size > 1) {
 848                 connected_policy_item =
 849                         common_entry->policies[1]->create_item_func();
 850                 memcpy(&connected_policy_item->creation_time,
 851                         &policy_item->creation_time,
 852                         sizeof(struct timeval));
 853                 connected_policy_item->key = policy_item->key;
 854                 connected_policy_item->key_size = policy_item->key_size;
 855
 856                 connected_policy_item->connected_item = policy_item;
 857                 policy_item->connected_item = connected_policy_item;
 858         }
 859
 860         item_data.fifo_policy_item = policy_item;
 861
 862         common_entry->policies[0]->add_item_func(common_entry->policies[0],
 863                 policy_item);
 864         if (common_entry->policies_size > 1)
 865                 common_entry->policies[1]->add_item_func(
 866                         common_entry->policies[1], connected_policy_item);
 867
 868         HASHTABLE_ENTRY_STORE(cache_ht_, item, &item_data);
 869         ++common_entry->items_size;
 870
 871         if ((common_entry->common_params.max_elemsize != 0) &&
 872                 (common_entry->items_size >
 873                 common_entry->common_params.max_elemsize)) {
 874                 if (common_entry->policies_size > 1) {
 875                         policy = common_entry->policies[1];
 876                         connected_policy = common_entry->policies[0];
 877                 } else {
 878                         policy = common_entry->policies[0];
 879                         connected_policy = NULL;
 880                 }
 881
 882                 flush_cache_policy(common_entry, policy, connected_policy,
 883                         cache_elemsize_common_continue_func);
 884         }
 885
 886         TRACE_OUT(cache_write);
 887         return (0);
 888 }
 889
 890 /*
 891  * Initializes the write session for the specified multipart entry. This
 892  * session then should be filled with data either committed or abandoned by
 893  * using close_cache_mp_write_session or abandon_cache_mp_write_session
 894  * respectively.
 895  * Returns NULL on errors (when there are too many opened write sessions for
 896  * the entry).
 897  */
 898 struct cache_mp_write_session_ *
 899 open_cache_mp_write_session(struct cache_entry_ *entry)
 900 {
 901         struct cache_mp_entry_  *mp_entry;
 902         struct cache_mp_write_session_  *retval;
 903
 904         TRACE_IN(open_cache_mp_write_session);
 905         assert(entry != NULL);
 906         assert(entry->params->entry_type == CET_MULTIPART);
 907         mp_entry = (struct cache_mp_entry_ *)entry;
 908
 909         if ((mp_entry->mp_params.max_sessions > 0) &&
 910                 (mp_entry->ws_size == mp_entry->mp_params.max_sessions)) {
 911                 TRACE_OUT(open_cache_mp_write_session);
 912                 return (NULL);
 913         }
 914
 915         retval = (struct cache_mp_write_session_ *)calloc(1,
 916                 sizeof(struct cache_mp_write_session_));
 917         assert(retval != NULL);
 918
 919         TAILQ_INIT(&retval->items);
 920         retval->parent_entry = mp_entry;
 921
 922         TAILQ_INSERT_HEAD(&mp_entry->ws_head, retval, entries);
 923         ++mp_entry->ws_size;
 924
 925         TRACE_OUT(open_cache_mp_write_session);
 926         return (retval);
 927 }
 928
 929 /*
 930  * Writes data to the specified session. Return 0 on success and -1 on errors
 931  * (when write session size limit is exceeded).
 932  */
 933 int
 934 cache_mp_write(struct cache_mp_write_session_ *ws, char *data,
 935         size_t data_size)
 936 {
 937         struct cache_mp_data_item_      *new_item;
 938
 939         TRACE_IN(cache_mp_write);
 940         assert(ws != NULL);
 941         assert(ws->parent_entry != NULL);
 942         assert(ws->parent_entry->params->entry_type == CET_MULTIPART);
 943
 944         if ((ws->parent_entry->mp_params.max_elemsize > 0) &&
 945                 (ws->parent_entry->mp_params.max_elemsize == ws->items_size)) {
 946                 TRACE_OUT(cache_mp_write);
 947                 return (-1);
 948         }
 949
 950         new_item = (struct cache_mp_data_item_ *)calloc(1,
 951                 sizeof(struct cache_mp_data_item_));
 952         assert(new_item != NULL);
 953
 954         new_item->value = (char *)malloc(data_size);
 955         assert(new_item->value != NULL);
 956         memcpy(new_item->value, data, data_size);
 957         new_item->value_size = data_size;
 958
 959         TAILQ_INSERT_TAIL(&ws->items, new_item, entries);
 960         ++ws->items_size;
 961
 962         TRACE_OUT(cache_mp_write);
 963         return (0);
 964 }
 965
 966 /*
 967  * Abandons the write session and frees all the connected resources.
 968  */
 969 void
 970 abandon_cache_mp_write_session(struct cache_mp_write_session_ *ws)
 971 {
 972
 973         TRACE_IN(abandon_cache_mp_write_session);
 974         assert(ws != NULL);
 975         assert(ws->parent_entry != NULL);
 976         assert(ws->parent_entry->params->entry_type == CET_MULTIPART);
 977
 978         TAILQ_REMOVE(&ws->parent_entry->ws_head, ws, entries);
 979         --ws->parent_entry->ws_size;
 980
 981         destroy_cache_mp_write_session(ws);
 982         TRACE_OUT(abandon_cache_mp_write_session);
 983 }
 984
 985 /*
 986  * Commits the session to the entry, for which it was created.
 987  */
 988 void
 989 close_cache_mp_write_session(struct cache_mp_write_session_ *ws)
 990 {
 991
 992         TRACE_IN(close_cache_mp_write_session);
 993         assert(ws != NULL);
 994         assert(ws->parent_entry != NULL);
 995         assert(ws->parent_entry->params->entry_type == CET_MULTIPART);
 996
 997         TAILQ_REMOVE(&ws->parent_entry->ws_head, ws, entries);
 998         --ws->parent_entry->ws_size;
 999
1000         if (ws->parent_entry->completed_write_session == NULL) {
1001                 /*
1002                  * If there is no completed session yet, this will be the one
1003                  */
1004                 ws->parent_entry->get_time_func(
1005                         &ws->parent_entry->creation_time);
1006                 ws->parent_entry->completed_write_session = ws;
1007         } else {
1008                 /*
1009                  * If there is a completed session, then we'll save our session
1010                  * as a pending session. If there is already a pending session,
1011                  * it would be destroyed.
1012                  */
1013                 if (ws->parent_entry->pending_write_session != NULL)
1014                         destroy_cache_mp_write_session(
1015                                 ws->parent_entry->pending_write_session);
1016
1017                 ws->parent_entry->pending_write_session = ws;
1018         }
1019         TRACE_OUT(close_cache_mp_write_session);
1020 }
1021
1022 /*
1023  * Opens read session for the specified entry. Returns NULL on errors (when
1024  * there are no data in the entry, or the data are obsolete).
1025  */
1026 struct cache_mp_read_session_ *
1027 open_cache_mp_read_session(struct cache_entry_ *entry)
1028 {
1029         struct cache_mp_entry_                  *mp_entry;
1030         struct cache_mp_read_session_   *retval;
1031
1032         TRACE_IN(open_cache_mp_read_session);
1033         assert(entry != NULL);
1034         assert(entry->params->entry_type == CET_MULTIPART);
1035         mp_entry = (struct cache_mp_entry_ *)entry;
1036
1037         if (mp_entry->completed_write_session == NULL) {
1038                 TRACE_OUT(open_cache_mp_read_session);
1039                 return (NULL);
1040         }
1041
1042         if ((mp_entry->mp_params.max_lifetime.tv_sec != 0)
1043                 || (mp_entry->mp_params.max_lifetime.tv_usec != 0)) {
1044                 if (mp_entry->last_request_time.tv_sec -
1045                         mp_entry->last_request_time.tv_sec >
1046                         mp_entry->mp_params.max_lifetime.tv_sec) {
1047                         flush_cache_entry(entry);
1048                         TRACE_OUT(open_cache_mp_read_session);
1049                         return (NULL);
1050                 }
1051         }
1052
1053         retval = (struct cache_mp_read_session_ *)calloc(1,
1054                 sizeof(struct cache_mp_read_session_));
1055         assert(retval != NULL);
1056
1057         retval->parent_entry = mp_entry;
1058         retval->current_item = TAILQ_FIRST(
1059                 &mp_entry->completed_write_session->items);
1060
1061         TAILQ_INSERT_HEAD(&mp_entry->rs_head, retval, entries);
1062         ++mp_entry->rs_size;
1063
1064         mp_entry->get_time_func(&mp_entry->last_request_time);
1065         TRACE_OUT(open_cache_mp_read_session);
1066         return (retval);
1067 }
1068
1069 /*
1070  * Reads the data from the read session - step by step.
1071  * Returns 0 on success, -1 on error (when there are no more data), and -2 if
1072  * the data_size is too small.  In the last case, data_size would be filled
1073  * the proper value.
1074  */
1075 int
1076 cache_mp_read(struct cache_mp_read_session_ *rs, char *data, size_t *data_size)
1077 {
1078
1079         TRACE_IN(cache_mp_read);
1080         assert(rs != NULL);
1081
1082         if (rs->current_item == NULL) {
1083                 TRACE_OUT(cache_mp_read);
1084                 return (-1);
1085         }
1086
1087         if (rs->current_item->value_size > *data_size) {
1088                 *data_size = rs->current_item->value_size;
1089                 if (data == NULL) {
1090                         TRACE_OUT(cache_mp_read);
1091                         return (0);
1092                 }
1093
1094                 TRACE_OUT(cache_mp_read);
1095                 return (-2);
1096         }
1097
1098         *data_size = rs->current_item->value_size;
1099         memcpy(data, rs->current_item->value, rs->current_item->value_size);
1100         rs->current_item = TAILQ_NEXT(rs->current_item, entries);
1101
1102         TRACE_OUT(cache_mp_read);
1103         return (0);
1104 }
1105
1106 /*
1107  * Closes the read session. If there are no more read sessions and there is
1108  * a pending write session, it will be committed and old
1109  * completed_write_session will be destroyed.
1110  */
1111 void
1112 close_cache_mp_read_session(struct cache_mp_read_session_ *rs)
1113 {
1114
1115         TRACE_IN(close_cache_mp_read_session);
1116         assert(rs != NULL);
1117         assert(rs->parent_entry != NULL);
1118
1119         TAILQ_REMOVE(&rs->parent_entry->rs_head, rs, entries);
1120         --rs->parent_entry->rs_size;
1121
1122         if ((rs->parent_entry->rs_size == 0) &&
1123                 (rs->parent_entry->pending_write_session != NULL)) {
1124                 destroy_cache_mp_write_session(
1125                         rs->parent_entry->completed_write_session);
1126                 rs->parent_entry->completed_write_session =
1127                         rs->parent_entry->pending_write_session;
1128                 rs->parent_entry->pending_write_session = NULL;
1129         }
1130
1131         destroy_cache_mp_read_session(rs);
1132         TRACE_OUT(close_cache_mp_read_session);
1133 }
1134
1135 int
1136 transform_cache_entry(struct cache_entry_ *entry,
1137         enum cache_transformation_t transformation)
1138 {
1139
1140         TRACE_IN(transform_cache_entry);
1141         switch (transformation) {
1142         case CTT_CLEAR:
1143                 clear_cache_entry(entry);
1144                 TRACE_OUT(transform_cache_entry);
1145                 return (0);
1146         case CTT_FLUSH:
1147                 flush_cache_entry(entry);
1148                 TRACE_OUT(transform_cache_entry);
1149                 return (0);
1150         default:
1151                 TRACE_OUT(transform_cache_entry);
1152                 return (-1);
1153         }
1154 }
1155
1156 int
1157 transform_cache_entry_part(struct cache_entry_ *entry,
1158         enum cache_transformation_t transformation, const char *key_part,
1159         size_t key_part_size, enum part_position_t part_position)
1160 {
1161         struct cache_common_entry_ *common_entry;
1162         struct cache_ht_item_ *ht_item;
1163         struct cache_ht_item_data_ *ht_item_data, ht_key;
1164
1165         struct cache_policy_item_ *item, *connected_item;
1166
1167         TRACE_IN(transform_cache_entry_part);
1168         if (entry->params->entry_type != CET_COMMON) {
1169                 TRACE_OUT(transform_cache_entry_part);
1170                 return (-1);
1171         }
1172
1173         if (transformation != CTT_CLEAR) {
1174                 TRACE_OUT(transform_cache_entry_part);
1175                 return (-1);
1176         }
1177
1178         memset(&ht_key, 0, sizeof(struct cache_ht_item_data_));
1179         ht_key.key = (char *)key_part;  /* can't avoid casting here */
1180         ht_key.key_size = key_part_size;
1181
1182         common_entry = (struct cache_common_entry_ *)entry;
1183         HASHTABLE_FOREACH(&(common_entry->items), ht_item) {
1184                 do {
1185                         ht_item_data = HASHTABLE_ENTRY_FIND_SPECIAL(cache_ht_,
1186                                 ht_item, &ht_key,
1187                                 ht_items_fixed_size_left_cmp_func);
1188
1189                         if (ht_item_data != NULL) {
1190                             item = ht_item_data->fifo_policy_item;
1191                             connected_item = item->connected_item;
1192
1193                             common_entry->policies[0]->remove_item_func(
1194                                 common_entry->policies[0],
1195                                 item);
1196
1197                             free(ht_item_data->key);
1198                             free(ht_item_data->value);
1199                             HASHTABLE_ENTRY_REMOVE(cache_ht_, ht_item,
1200                                 ht_item_data);
1201                             --common_entry->items_size;
1202
1203                             common_entry->policies[0]->destroy_item_func(
1204                                 item);
1205                             if (common_entry->policies_size == 2) {
1206                                 common_entry->policies[1]->remove_item_func(
1207                                     common_entry->policies[1],
1208                                     connected_item);
1209                                 common_entry->policies[1]->destroy_item_func(
1210                                     connected_item);
1211                             }
1212                         }
1213                 } while (ht_item_data != NULL);
1214         }
1215
1216         TRACE_OUT(transform_cache_entry_part);
1217         return (0);
1218 }