lib/libcrypto/lhash/lhash.c

   1 /* $OpenBSD: lhash.c,v 1.18 2016/11/08 20:20:06 miod Exp $ */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59 /* Code for dynamic hash table routines
  60  * Author - Eric Young v 2.0
  61  *
  62  * 2.2 eay - added #include "crypto.h" so the memory leak checking code is
  63  *           present. eay 18-Jun-98
  64  *
  65  * 2.1 eay - Added an 'error in last operation' flag. eay 6-May-98
  66  *
  67  * 2.0 eay - Fixed a bug that occurred when using lh_delete
  68  *           from inside lh_doall().  As entries were deleted,
  69  *           the 'table' was 'contract()ed', making some entries
  70  *           jump from the end of the table to the start, there by
  71  *           skipping the lh_doall() processing. eay - 4/12/95
  72  *
  73  * 1.9 eay - Fixed a memory leak in lh_free, the LHASH_NODEs
  74  *           were not being free()ed. 21/11/95
  75  *
  76  * 1.8 eay - Put the stats routines into a separate file, lh_stats.c
  77  *           19/09/95
  78  *
  79  * 1.7 eay - Removed the fputs() for realloc failures - the code
  80  *           should silently tolerate them.  I have also fixed things
  81  *           lint complained about 04/05/95
  82  *
  83  * 1.6 eay - Fixed an invalid pointers in contract/expand 27/07/92
  84  *
  85  * 1.5 eay - Fixed a misuse of realloc in expand 02/03/1992
  86  *
  87  * 1.4 eay - Fixed lh_doall so the function can call lh_delete 28/05/91
  88  *
  89  * 1.3 eay - Fixed a few lint problems 19/3/1991
  90  *
  91  * 1.2 eay - Fixed lh_doall problem 13/3/1991
  92  *
  93  * 1.1 eay - Added lh_doall
  94  *
  95  * 1.0 eay - First version
  96  */
  97 #include <stdio.h>
  98 #include <string.h>
  99 #include <stdlib.h>
 100
 101 #include <openssl/opensslconf.h>
 102
 103 #include <openssl/crypto.h>
 104 #include <openssl/lhash.h>
 105
 106 #undef MIN_NODES
 107 #define MIN_NODES       16
 108 #define UP_LOAD         (2*LH_LOAD_MULT) /* load times 256  (default 2) */
 109 #define DOWN_LOAD       (LH_LOAD_MULT)   /* load times 256  (default 1) */
 110
 111 static void expand(_LHASH *lh);
 112 static void contract(_LHASH *lh);
 113 static LHASH_NODE **getrn(_LHASH *lh, const void *data, unsigned long *rhash);
 114
 115 _LHASH *
 116 lh_new(LHASH_HASH_FN_TYPE h, LHASH_COMP_FN_TYPE c)
 117 {
 118         _LHASH *ret;
 119         int i;
 120
 121         if ((ret = malloc(sizeof(_LHASH))) == NULL)
 122                 goto err0;
 123         if ((ret->b = reallocarray(NULL, MIN_NODES, sizeof(LHASH_NODE *))) == NULL)
 124                 goto err1;
 125         for (i = 0; i < MIN_NODES; i++)
 126                 ret->b[i] = NULL;
 127         ret->comp = ((c == NULL) ? (LHASH_COMP_FN_TYPE)strcmp : c);
 128         ret->hash = ((h == NULL) ? (LHASH_HASH_FN_TYPE)lh_strhash : h);
 129         ret->num_nodes = MIN_NODES / 2;
 130         ret->num_alloc_nodes = MIN_NODES;
 131         ret->p = 0;
 132         ret->pmax = MIN_NODES / 2;
 133         ret->up_load = UP_LOAD;
 134         ret->down_load = DOWN_LOAD;
 135         ret->num_items = 0;
 136
 137         ret->num_expands = 0;
 138         ret->num_expand_reallocs = 0;
 139         ret->num_contracts = 0;
 140         ret->num_contract_reallocs = 0;
 141         ret->num_hash_calls = 0;
 142         ret->num_comp_calls = 0;
 143         ret->num_insert = 0;
 144         ret->num_replace = 0;
 145         ret->num_delete = 0;
 146         ret->num_no_delete = 0;
 147         ret->num_retrieve = 0;
 148         ret->num_retrieve_miss = 0;
 149         ret->num_hash_comps = 0;
 150
 151         ret->error = 0;
 152         return (ret);
 153
 154 err1:
 155         free(ret);
 156 err0:
 157         return (NULL);
 158 }
 159
 160 void
 161 lh_free(_LHASH *lh)
 162 {
 163         unsigned int i;
 164         LHASH_NODE *n, *nn;
 165
 166         if (lh == NULL)
 167                 return;
 168
 169         for (i = 0; i < lh->num_nodes; i++) {
 170                 n = lh->b[i];
 171                 while (n != NULL) {
 172                         nn = n->next;
 173                         free(n);
 174                         n = nn;
 175                 }
 176         }
 177         free(lh->b);
 178         free(lh);
 179 }
 180
 181 void *
 182 lh_insert(_LHASH *lh, void *data)
 183 {
 184         unsigned long hash;
 185         LHASH_NODE *nn, **rn;
 186         void *ret;
 187
 188         lh->error = 0;
 189         if (lh->up_load <= (lh->num_items * LH_LOAD_MULT / lh->num_nodes))
 190                 expand(lh);
 191
 192         rn = getrn(lh, data, &hash);
 193
 194         if (*rn == NULL) {
 195                 if ((nn = malloc(sizeof(LHASH_NODE))) == NULL) {
 196                         lh->error++;
 197                         return (NULL);
 198                 }
 199                 nn->data = data;
 200                 nn->next = NULL;
 201 #ifndef OPENSSL_NO_HASH_COMP
 202                 nn->hash = hash;
 203 #endif
 204                 *rn = nn;
 205                 ret = NULL;
 206                 lh->num_insert++;
 207                 lh->num_items++;
 208         }
 209         else /* replace same key */
 210         {
 211                 ret = (*rn)->data;
 212                 (*rn)->data = data;
 213                 lh->num_replace++;
 214         }
 215         return (ret);
 216 }
 217
 218 void *
 219 lh_delete(_LHASH *lh, const void *data)
 220 {
 221         unsigned long hash;
 222         LHASH_NODE *nn, **rn;
 223         void *ret;
 224
 225         lh->error = 0;
 226         rn = getrn(lh, data, &hash);
 227
 228         if (*rn == NULL) {
 229                 lh->num_no_delete++;
 230                 return (NULL);
 231         } else {
 232                 nn= *rn;
 233                 *rn = nn->next;
 234                 ret = nn->data;
 235                 free(nn);
 236                 lh->num_delete++;
 237         }
 238
 239         lh->num_items--;
 240         if ((lh->num_nodes > MIN_NODES) &&
 241             (lh->down_load >= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)))
 242                 contract(lh);
 243
 244         return (ret);
 245 }
 246
 247 void *
 248 lh_retrieve(_LHASH *lh, const void *data)
 249 {
 250         unsigned long hash;
 251         LHASH_NODE **rn;
 252         void *ret;
 253
 254         lh->error = 0;
 255         rn = getrn(lh, data, &hash);
 256
 257         if (*rn == NULL) {
 258                 lh->num_retrieve_miss++;
 259                 return (NULL);
 260         } else {
 261                 ret = (*rn)->data;
 262                 lh->num_retrieve++;
 263         }
 264         return (ret);
 265 }
 266
 267 static void
 268 doall_util_fn(_LHASH *lh, int use_arg, LHASH_DOALL_FN_TYPE func,
 269     LHASH_DOALL_ARG_FN_TYPE func_arg, void *arg)
 270 {
 271         int i;
 272         LHASH_NODE *a, *n;
 273
 274         if (lh == NULL)
 275                 return;
 276
 277         /* reverse the order so we search from 'top to bottom'
 278          * We were having memory leaks otherwise */
 279         for (i = lh->num_nodes - 1; i >= 0; i--) {
 280                 a = lh->b[i];
 281                 while (a != NULL) {
 282                         /* 28/05/91 - eay - n added so items can be deleted
 283                          * via lh_doall */
 284                         /* 22/05/08 - ben - eh? since a is not passed,
 285                          * this should not be needed */
 286                         n = a->next;
 287                         if (use_arg)
 288                                 func_arg(a->data, arg);
 289                         else
 290                                 func(a->data);
 291                         a = n;
 292                 }
 293         }
 294 }
 295
 296 void
 297 lh_doall(_LHASH *lh, LHASH_DOALL_FN_TYPE func)
 298 {
 299         doall_util_fn(lh, 0, func, (LHASH_DOALL_ARG_FN_TYPE)0, NULL);
 300 }
 301
 302 void
 303 lh_doall_arg(_LHASH *lh, LHASH_DOALL_ARG_FN_TYPE func, void *arg)
 304 {
 305         doall_util_fn(lh, 1, (LHASH_DOALL_FN_TYPE)0, func, arg);
 306 }
 307
 308 static void
 309 expand(_LHASH *lh)
 310 {
 311         LHASH_NODE **n, **n1, **n2, *np;
 312         unsigned int p, i, j;
 313         unsigned long hash, nni;
 314
 315         lh->num_nodes++;
 316         lh->num_expands++;
 317         p = (int)lh->p++;
 318         n1 = &(lh->b[p]);
 319         n2 = &(lh->b[p + (int)lh->pmax]);
 320         *n2 = NULL;        /* 27/07/92 - eay - undefined pointer bug */
 321         nni = lh->num_alloc_nodes;
 322
 323         for (np = *n1; np != NULL; ) {
 324 #ifndef OPENSSL_NO_HASH_COMP
 325                 hash = np->hash;
 326 #else
 327                 hash = lh->hash(np->data);
 328                 lh->num_hash_calls++;
 329 #endif
 330                 if ((hash % nni) != p) { /* move it */
 331                         *n1 = (*n1)->next;
 332                         np->next= *n2;
 333                         *n2 = np;
 334                 } else
 335                         n1 = &((*n1)->next);
 336                 np= *n1;
 337         }
 338
 339         if ((lh->p) >= lh->pmax) {
 340                 j = (int)lh->num_alloc_nodes * 2;
 341                 n = reallocarray(lh->b, j, sizeof(LHASH_NODE *));
 342                 if (n == NULL) {
 343 /*                      fputs("realloc error in lhash", stderr); */
 344                         lh->error++;
 345                         lh->p = 0;
 346                         return;
 347                 }
 348                 /* else */
 349                 for (i = (int)lh->num_alloc_nodes; i < j; i++)/* 26/02/92 eay */
 350                         n[i] = NULL;                      /* 02/03/92 eay */
 351                 lh->pmax = lh->num_alloc_nodes;
 352                 lh->num_alloc_nodes = j;
 353                 lh->num_expand_reallocs++;
 354                 lh->p = 0;
 355                 lh->b = n;
 356         }
 357 }
 358
 359 static void
 360 contract(_LHASH *lh)
 361 {
 362         LHASH_NODE **n, *n1, *np;
 363
 364         np = lh->b[lh->p + lh->pmax - 1];
 365         lh->b[lh->p+lh->pmax - 1] = NULL; /* 24/07-92 - eay - weird but :-( */
 366         if (lh->p == 0) {
 367                 n = reallocarray(lh->b, lh->pmax, sizeof(LHASH_NODE *));
 368                 if (n == NULL) {
 369 /*                      fputs("realloc error in lhash", stderr); */
 370                         lh->error++;
 371                         return;
 372                 }
 373                 lh->num_contract_reallocs++;
 374                 lh->num_alloc_nodes /= 2;
 375                 lh->pmax /= 2;
 376                 lh->p = lh->pmax - 1;
 377                 lh->b = n;
 378         } else
 379                 lh->p--;
 380
 381         lh->num_nodes--;
 382         lh->num_contracts++;
 383
 384         n1 = lh->b[(int)lh->p];
 385         if (n1 == NULL)
 386                 lh->b[(int)lh->p] = np;
 387         else {
 388                 while (n1->next != NULL)
 389                         n1 = n1->next;
 390                 n1->next = np;
 391         }
 392 }
 393
 394 static LHASH_NODE **getrn(_LHASH *lh, const void *data, unsigned long *rhash)
 395 {
 396         LHASH_NODE **ret, *n1;
 397         unsigned long hash, nn;
 398         LHASH_COMP_FN_TYPE cf;
 399
 400         hash = (*(lh->hash))(data);
 401         lh->num_hash_calls++;
 402         *rhash = hash;
 403
 404         nn = hash % lh->pmax;
 405         if (nn < lh->p)
 406                 nn = hash % lh->num_alloc_nodes;
 407
 408         cf = lh->comp;
 409         ret = &(lh->b[(int)nn]);
 410         for (n1 = *ret; n1 != NULL; n1 = n1->next) {
 411 #ifndef OPENSSL_NO_HASH_COMP
 412                 lh->num_hash_comps++;
 413                 if (n1->hash != hash) {
 414                         ret = &(n1->next);
 415                         continue;
 416                 }
 417 #endif
 418                 lh->num_comp_calls++;
 419                 if (cf(n1->data, data) == 0)
 420                         break;
 421                 ret = &(n1->next);
 422         }
 423         return (ret);
 424 }
 425
 426 /* The following hash seems to work very well on normal text strings
 427  * no collisions on /usr/dict/words and it distributes on %2^n quite
 428  * well, not as good as MD5, but still good.
 429  */
 430 unsigned long
 431 lh_strhash(const char *c)
 432 {
 433         unsigned long ret = 0;
 434         unsigned long n, v;
 435         unsigned int r;
 436
 437         if (c == NULL || *c == '\0')
 438                 return ret;
 439
 440         n = 0x100;
 441         while (*c) {
 442                 v = n | *c;
 443                 n += 0x100;
 444                 if ((r = ((v >> 2) ^ v) & 0x0f) != 0)
 445                         ret = (ret << r) | (ret >> (32 - r));
 446                 ret &= 0xFFFFFFFFUL;
 447                 ret ^= v * v;
 448                 c++;
 449         }
 450         return (ret >> 16) ^ ret;
 451 }
 452
 453 unsigned long
 454 lh_num_items(const _LHASH *lh)
 455 {
 456         return lh ? lh->num_items : 0;
 457 }