Security/libsecurity_asn1/lib/plarena.c

   1 /*
   2  * Copyright (c) 2003-2006,2008,2010-2012 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * The contents of this file are subject to the Mozilla Public
  25  * License Version 1.1 (the "License"); you may not use this file
  26  * except in compliance with the License. You may obtain a copy of
  27  * the License at http://www.mozilla.org/MPL/
  28  *
  29  * Software distributed under the License is distributed on an "AS
  30  * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
  31  * implied. See the License for the specific language governing
  32  * rights and limitations under the License.
  33  *
  34  * The Original Code is the Netscape Portable Runtime (NSPR).
  35  *
  36  * The Initial Developer of the Original Code is Netscape
  37  * Communications Corporation.  Portions created by Netscape are
  38  * Copyright (C) 1998-2000 Netscape Communications Corporation.  All
  39  * Rights Reserved.
  40  *
  41  * Contributor(s):
  42  *
  43  * Alternatively, the contents of this file may be used under the
  44  * terms of the GNU General Public License Version 2 or later (the
  45  * "GPL"), in which case the provisions of the GPL are applicable
  46  * instead of those above.  If you wish to allow use of your
  47  * version of this file only under the terms of the GPL and not to
  48  * allow others to use your version of this file under the MPL,
  49  * indicate your decision by deleting the provisions above and
  50  * replace them with the notice and other provisions required by
  51  * the GPL.  If you do not delete the provisions above, a recipient
  52  * may use your version of this file under either the MPL or the
  53  * GPL.
  54  */
  55
  56 /*
  57  * Lifetime-based fast allocation, inspired by much prior art, including
  58  * "Fast Allocation and Deallocation of Memory Based on Object Lifetimes"
  59  * David R. Hanson, Software -- Practice and Experience, Vol. 20(1).
  60  */
  61 #include <stdlib.h>
  62 #include <string.h>
  63 #include "plarena.h"
  64 #include "prmem.h"
  65 #include "prbit.h"
  66 #include "prlog.h"
  67 #include "prinit.h"
  68
  69 #ifdef PL_ARENAMETER
  70 static PLArenaStats *arena_stats_list;
  71
  72 #define COUNT(pool,what)  (pool)->stats.what++
  73 #else
  74 #define COUNT(pool,what)  /* nothing */
  75 #endif
  76
  77 #define PL_ARENA_DEFAULT_ALIGN  sizeof(double)
  78
  79 PR_IMPLEMENT(void) PL_InitArenaPool(
  80     PLArenaPool *pool, const char *name, PRUint32 size, PRUint32 align)
  81 {
  82 #if !defined (__GNUC__)
  83 #pragma unused (name)
  84 #endif
  85
  86     if (align == 0)
  87         align = PL_ARENA_DEFAULT_ALIGN;
  88     pool->mask = PR_BITMASK(PR_CeilingLog2(align));
  89     pool->first.next = NULL;
  90     pool->first.base = pool->first.avail = pool->first.limit =
  91         (PRUword)PL_ARENA_ALIGN(pool, &pool->first + 1);
  92     pool->current = &pool->first;
  93     pool->arenasize = size;
  94 #ifdef PL_ARENAMETER
  95     memset(&pool->stats, 0, sizeof pool->stats);
  96     pool->stats.name = strdup(name);
  97     pool->stats.next = arena_stats_list;
  98     arena_stats_list = &pool->stats;
  99 #endif
 100 }
 101
 102 #if __APPLE__
 103 #define MAX_SIZE (PR_UINT32_MAX >> 1)
 104 #endif
 105
 106 /*
 107 ** PL_ArenaAllocate() -- allocate space from an arena pool
 108 **
 109 ** Description: PL_ArenaAllocate() allocates space from an arena
 110 ** pool.
 111 **
 112 ** First, try to satisfy the request from arenas starting at
 113 ** pool->current. Then try to allocate a new arena from the heap.
 114 **
 115 ** Returns: pointer to allocated space or NULL
 116 **
 117 ** Notes: The original implementation had some difficult to
 118 ** solve bugs; the code was difficult to read. Sometimes it's
 119 ** just easier to rewrite it. I did that. larryh.
 120 **
 121 ** See also: bugzilla: 45343.
 122 **
 123 */
 124
 125 PR_IMPLEMENT(void *) PL_ArenaAllocate(PLArenaPool *pool, PRUint32 nb)
 126 {
 127     PLArena *a;
 128     char *rp;     /* returned pointer */
 129
 130     PR_ASSERT((nb & pool->mask) == 0);
 131 #ifdef __APPLE__
 132     nb = PL_ARENA_ALIGN(pool, nb); /* force alignment, cast is useless/causes warning. */
 133 #else
 134     nb = (PRUword)PL_ARENA_ALIGN(pool, nb); /* force alignment */
 135 #endif
 136
 137     /* attempt to allocate from arenas at pool->current */
 138     {
 139         a = pool->current;
 140         do {
 141             if ( nb <= a->limit - a->avail )  {
 142                 pool->current = a;
 143                 rp = (char *)a->avail;
 144                 a->avail += nb;
 145                 return rp;
 146             }
 147         } while( NULL != (a = a->next) );
 148     }
 149
 150     /* attempt to allocate from the heap */
 151     {
 152         PRUint32 sz = PR_MAX(pool->arenasize, nb);
 153         if (PR_UINT32_MAX - sz < sizeof *a + pool->mask) {
 154             a = NULL;
 155         } else {
 156             sz += sizeof *a + pool->mask;  /* header and alignment slop */
 157             a = (PLArena*)PR_MALLOC(sz);
 158         }
 159 #ifdef __APPLE__
 160         // Check for integer overflow on a->avail += nb
 161         PRUword a_avail_tmp=(PRUword)PL_ARENA_ALIGN(pool, a + 1);
 162         if (a_avail_tmp + nb < a_avail_tmp)
 163         {
 164             PR_FREEIF(a); // Set a back to NULL
 165         }
 166 #endif
 167         if ( NULL != a )  {
 168             a->limit = (PRUword)a + sz;
 169 #ifdef __APPLE__
 170             a->base = a->avail = a_avail_tmp;
 171 #else
 172             a->base = a->avail = (PRUword)PL_ARENA_ALIGN(pool, a + 1);
 173 #endif
 174             rp = (char *)a->avail;
 175             a->avail += nb;
 176             /* the newly allocated arena is linked after pool->current
 177             *  and becomes pool->current */
 178             a->next = pool->current->next;
 179             pool->current->next = a;
 180             pool->current = a;
 181             if ( NULL == pool->first.next )
 182                 pool->first.next = a;
 183             PL_COUNT_ARENA(pool,++);
 184             COUNT(pool, nmallocs);
 185             return(rp);
 186         }
 187     }
 188
 189     /* we got to here, and there's no memory to allocate */
 190     return(NULL);
 191 } /* --- end PL_ArenaAllocate() --- */
 192
 193 /*
 194  * Grow, a.k.a. realloc. The PL_ARENA_GROW macro has already handled
 195  * the possible grow-in-place action in which the current PLArena is the
 196  * source of the incoming pointer, and there is room in that arena for
 197  * the requested size.
 198  */
 199 PR_IMPLEMENT(void *) PL_ArenaGrow(
 200     PLArenaPool *pool, void *p, PRUint32 origSize, PRUint32 incr)
 201 {
 202     void *newp;
 203         PLArena *thisArena;
 204         PLArena *lastArena;
 205         PRUint32 origAlignSize;         // bytes currently reserved for caller
 206         PRUint32 newSize;                       // bytes actually mallocd here
 207
 208         /* expand at least by 2x */
 209         origAlignSize = PL_ARENA_ALIGN(pool, origSize);
 210     newSize = PR_MAX(origAlignSize+incr, 2*origAlignSize);
 211     newSize = PL_ARENA_ALIGN(pool, newSize);
 212 #if __APPLE__
 213     // Enforce maximal size before any potential implicit truncation
 214     if (newSize>=MAX_SIZE || origSize>=MAX_SIZE || incr>=MAX_SIZE) {
 215         return NULL;
 216     }
 217 #endif
 218     PL_ARENA_ALLOCATE(newp, pool, newSize);
 219     if (newp == NULL) {
 220         return NULL;
 221     }
 222         /*
 223          * Trim back the memory we just allocated to the amount our caller really
 224          * needs, leaving the remainder for grow-in-place on subsequent calls
 225          * to PL_ARENA_GROW.
 226          */
 227         PRUint32 newAlignSize = PL_ARENA_ALIGN(pool, origSize+incr);
 228         PR_ASSERT(pool->current->avail == ((PRUword)newp + newSize));
 229         pool->current->avail = (PRUword)newp + newAlignSize;
 230         PR_ASSERT(pool->current->avail <= pool->current->limit);
 231
 232         /* "realloc" */
 233         memcpy(newp, p, origSize);
 234
 235         /*
 236          * Free old memory only if it's the entire outstanding allocated
 237          * memory associated with one of our known PLArenas.
 238          */
 239         lastArena = &pool->first;                       /* pool->first always empty */
 240         thisArena = lastArena->next;            /* so, start here */
 241
 242         PRUword origPtr = (PRUword)p;
 243         while(thisArena != NULL) {
 244                 if(origPtr == thisArena->base) {
 245                         if((origPtr + origAlignSize) == thisArena->avail) {
 246                                 /* unlink */
 247                                 lastArena->next = thisArena->next;
 248
 249                                 /* and free */
 250                                 PL_CLEAR_ARENA(thisArena);
 251                                 PL_COUNT_ARENA(pool,--);
 252                                 PR_DELETE(thisArena);
 253                                 break;
 254                         }
 255                 }
 256                 lastArena = thisArena;
 257                 thisArena = thisArena->next;
 258         }
 259         /*
 260          * Note: inability to free is not an error; it just causes a temporary leak
 261          * of the old buffer (until the arena pool is freed, of course).
 262          */
 263     return newp;
 264 }
 265
 266 static void ClearArenaList(PLArena *a, PRInt32 pattern)
 267 {
 268
 269     for (; a; a = a->next) {
 270         PR_ASSERT(a->base <= a->avail && a->avail <= a->limit);
 271         a->avail = a->base;
 272         PL_CLEAR_UNUSED_PATTERN(a, pattern);
 273     }
 274 }
 275
 276 PR_IMPLEMENT(void) PL_ClearArenaPool(PLArenaPool *pool, PRInt32 pattern)
 277 {
 278     ClearArenaList(pool->first.next, pattern);
 279 }
 280
 281 /*
 282  * Free tail arenas linked after head, which may not be the true list head.
 283  * Reset pool->current to point to head in case it pointed at a tail arena.
 284  */
 285 static void FreeArenaList(PLArenaPool *pool, PLArena *head, PRBool reallyFree)
 286 {
 287     PLArena **ap, *a;
 288
 289     ap = &head->next;
 290     a = *ap;
 291     if (!a)
 292         return;
 293
 294         do {
 295                 *ap = a->next;
 296                 PL_CLEAR_ARENA(a);
 297                 PL_COUNT_ARENA(pool,--);
 298                 PR_DELETE(a);
 299         } while ((a = *ap) != 0);
 300
 301     pool->current = head;
 302 }
 303
 304 PR_IMPLEMENT(void) PL_ArenaRelease(PLArenaPool *pool, char *mark)
 305 {
 306         #if ARENA_MARK_ENABLE
 307     PLArena *a;
 308
 309     for (a = pool->first.next; a; a = a->next) {
 310         if (PR_UPTRDIFF(mark, a->base) < PR_UPTRDIFF(a->avail, a->base)) {
 311             a->avail = (PRUword)PL_ARENA_ALIGN(pool, mark);
 312             FreeArenaList(pool, a, PR_FALSE);
 313             return;
 314         }
 315     }
 316         #endif  /* ARENA_MARK_ENABLE */
 317 }
 318
 319 PR_IMPLEMENT(void) PL_FreeArenaPool(PLArenaPool *pool)
 320 {
 321     FreeArenaList(pool, &pool->first, PR_FALSE);
 322     COUNT(pool, ndeallocs);
 323 }
 324
 325 PR_IMPLEMENT(void) PL_FinishArenaPool(PLArenaPool *pool)
 326 {
 327     FreeArenaList(pool, &pool->first, PR_TRUE);
 328 #ifdef PL_ARENAMETER
 329     {
 330         PLArenaStats *stats, **statsp;
 331
 332         if (pool->stats.name)
 333             PR_DELETE(pool->stats.name);
 334         for (statsp = &arena_stats_list; (stats = *statsp) != 0;
 335              statsp = &stats->next) {
 336             if (stats == &pool->stats) {
 337                 *statsp = stats->next;
 338                 return;
 339             }
 340         }
 341     }
 342 #endif
 343 }
 344
 345 PR_IMPLEMENT(void) PL_CompactArenaPool(PLArenaPool *ap)
 346 {
 347 }
 348
 349 PR_IMPLEMENT(void) PL_ArenaFinish(void)
 350 {
 351 }
 352
 353 #ifdef PL_ARENAMETER
 354 PR_IMPLEMENT(void) PL_ArenaCountAllocation(PLArenaPool *pool, PRUint32 nb)
 355 {
 356     pool->stats.nallocs++;
 357     pool->stats.nbytes += nb;
 358     if (nb > pool->stats.maxalloc)
 359         pool->stats.maxalloc = nb;
 360     pool->stats.variance += nb * nb;
 361 }
 362
 363 PR_IMPLEMENT(void) PL_ArenaCountInplaceGrowth(
 364     PLArenaPool *pool, PRUint32 size, PRUint32 incr)
 365 {
 366     pool->stats.ninplace++;
 367 }
 368
 369 PR_IMPLEMENT(void) PL_ArenaCountGrowth(
 370     PLArenaPool *pool, PRUint32 size, PRUint32 incr)
 371 {
 372     pool->stats.ngrows++;
 373     pool->stats.nbytes += incr;
 374     pool->stats.variance -= size * size;
 375     size += incr;
 376     if (size > pool->stats.maxalloc)
 377         pool->stats.maxalloc = size;
 378     pool->stats.variance += size * size;
 379 }
 380
 381 PR_IMPLEMENT(void) PL_ArenaCountRelease(PLArenaPool *pool, char *mark)
 382 {
 383     pool->stats.nreleases++;
 384 }
 385
 386 PR_IMPLEMENT(void) PL_ArenaCountRetract(PLArenaPool *pool, char *mark)
 387 {
 388     pool->stats.nfastrels++;
 389 }
 390
 391 #include <math.h>
 392 #include <stdio.h>
 393
 394 PR_IMPLEMENT(void) PL_DumpArenaStats(FILE *fp)
 395 {
 396     PLArenaStats *stats;
 397     double mean, variance;
 398
 399     for (stats = arena_stats_list; stats; stats = stats->next) {
 400         if (stats->nallocs != 0) {
 401             mean = (double)stats->nbytes / stats->nallocs;
 402             variance = fabs(stats->variance / stats->nallocs - mean * mean);
 403         } else {
 404             mean = variance = 0;
 405         }
 406
 407         fprintf(fp, "\n%s allocation statistics:\n", stats->name);
 408         fprintf(fp, "              number of arenas: %u\n", stats->narenas);
 409         fprintf(fp, "         number of allocations: %u\n", stats->nallocs);
 410         fprintf(fp, " number of free arena reclaims: %u\n", stats->nreclaims);
 411         fprintf(fp, "        number of malloc calls: %u\n", stats->nmallocs);
 412         fprintf(fp, "       number of deallocations: %u\n", stats->ndeallocs);
 413         fprintf(fp, "  number of allocation growths: %u\n", stats->ngrows);
 414         fprintf(fp, "    number of in-place growths: %u\n", stats->ninplace);
 415         fprintf(fp, "number of released allocations: %u\n", stats->nreleases);
 416         fprintf(fp, "       number of fast releases: %u\n", stats->nfastrels);
 417         fprintf(fp, "         total bytes allocated: %u\n", stats->nbytes);
 418         fprintf(fp, "          mean allocation size: %g\n", mean);
 419         fprintf(fp, "            standard deviation: %g\n", sqrt(variance));
 420         fprintf(fp, "       maximum allocation size: %u\n", stats->maxalloc);
 421     }
 422 }
 423 #endif /* PL_ARENAMETER */