malloc/hooks.c

   1 /* Malloc implementation for multiple threads without lock contention.
   2    Copyright (C) 2001-2006, 2007, 2008, 2009 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Wolfram Gloger <wg@malloc.de>, 2001.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public License as
   8    published by the Free Software Foundation; either version 2.1 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 /* What to do if the standard debugging hooks are in place and a
  22    corrupt pointer is detected: do nothing (0), print an error message
  23    (1), or call abort() (2). */
  24
  25 /* Hooks for debugging versions.  The initial hooks just call the
  26    initialization routine, then do the normal work. */
  27
  28 static Void_t*
  29 #if __STD_C
  30 malloc_hook_ini(size_t sz, const __malloc_ptr_t caller)
  31 #else
  32 malloc_hook_ini(sz, caller)
  33      size_t sz; const __malloc_ptr_t caller;
  34 #endif
  35 {
  36   __malloc_hook = NULL;
  37   ptmalloc_init();
  38   return public_mALLOc(sz);
  39 }
  40
  41 static Void_t*
  42 #if __STD_C
  43 realloc_hook_ini(Void_t* ptr, size_t sz, const __malloc_ptr_t caller)
  44 #else
  45 realloc_hook_ini(ptr, sz, caller)
  46      Void_t* ptr; size_t sz; const __malloc_ptr_t caller;
  47 #endif
  48 {
  49   __malloc_hook = NULL;
  50   __realloc_hook = NULL;
  51   ptmalloc_init();
  52   return public_rEALLOc(ptr, sz);
  53 }
  54
  55 static Void_t*
  56 #if __STD_C
  57 memalign_hook_ini(size_t alignment, size_t sz, const __malloc_ptr_t caller)
  58 #else
  59 memalign_hook_ini(alignment, sz, caller)
  60      size_t alignment; size_t sz; const __malloc_ptr_t caller;
  61 #endif
  62 {
  63   __memalign_hook = NULL;
  64   ptmalloc_init();
  65   return public_mEMALIGn(alignment, sz);
  66 }
  67
  68 /* Whether we are using malloc checking.  */
  69 static int using_malloc_checking;
  70
  71 /* A flag that is set by malloc_set_state, to signal that malloc checking
  72    must not be enabled on the request from the user (via the MALLOC_CHECK_
  73    environment variable).  It is reset by __malloc_check_init to tell
  74    malloc_set_state that the user has requested malloc checking.
  75
  76    The purpose of this flag is to make sure that malloc checking is not
  77    enabled when the heap to be restored was constructed without malloc
  78    checking, and thus does not contain the required magic bytes.
  79    Otherwise the heap would be corrupted by calls to free and realloc.  If
  80    it turns out that the heap was created with malloc checking and the
  81    user has requested it malloc_set_state just calls __malloc_check_init
  82    again to enable it.  On the other hand, reusing such a heap without
  83    further malloc checking is safe.  */
  84 static int disallow_malloc_check;
  85
  86 /* Activate a standard set of debugging hooks. */
  87 void
  88 __malloc_check_init()
  89 {
  90   if (disallow_malloc_check) {
  91     disallow_malloc_check = 0;
  92     return;
  93   }
  94   using_malloc_checking = 1;
  95   __malloc_hook = malloc_check;
  96   __free_hook = free_check;
  97   __realloc_hook = realloc_check;
  98   __memalign_hook = memalign_check;
  99 }
 100
 101 /* A simple, standard set of debugging hooks.  Overhead is `only' one
 102    byte per chunk; still this will catch most cases of double frees or
 103    overruns.  The goal here is to avoid obscure crashes due to invalid
 104    usage, unlike in the MALLOC_DEBUG code. */
 105
 106 #define MAGICBYTE(p) ( ( ((size_t)p >> 3) ^ ((size_t)p >> 11)) & 0xFF )
 107
 108 /* Instrument a chunk with overrun detector byte(s) and convert it
 109    into a user pointer with requested size sz. */
 110
 111 static Void_t*
 112 internal_function
 113 #if __STD_C
 114 mem2mem_check(Void_t *ptr, size_t sz)
 115 #else
 116 mem2mem_check(ptr, sz) Void_t *ptr; size_t sz;
 117 #endif
 118 {
 119   mchunkptr p;
 120   unsigned char* m_ptr = (unsigned char*)BOUNDED_N(ptr, sz);
 121   size_t i;
 122
 123   if (!ptr)
 124     return ptr;
 125   p = mem2chunk(ptr);
 126   for(i = chunksize(p) - (chunk_is_mmapped(p) ? 2*SIZE_SZ+1 : SIZE_SZ+1);
 127       i > sz;
 128       i -= 0xFF) {
 129     if(i-sz < 0x100) {
 130       m_ptr[i] = (unsigned char)(i-sz);
 131       break;
 132     }
 133     m_ptr[i] = 0xFF;
 134   }
 135   m_ptr[sz] = MAGICBYTE(p);
 136   return (Void_t*)m_ptr;
 137 }
 138
 139 /* Convert a pointer to be free()d or realloc()ed to a valid chunk
 140    pointer.  If the provided pointer is not valid, return NULL. */
 141
 142 static mchunkptr
 143 internal_function
 144 #if __STD_C
 145 mem2chunk_check(Void_t* mem, unsigned char **magic_p)
 146 #else
 147 mem2chunk_check(mem, magic_p) Void_t* mem; unsigned char **magic_p;
 148 #endif
 149 {
 150   mchunkptr p;
 151   INTERNAL_SIZE_T sz, c;
 152   unsigned char magic;
 153
 154   if(!aligned_OK(mem)) return NULL;
 155   p = mem2chunk(mem);
 156   if (!chunk_is_mmapped(p)) {
 157     /* Must be a chunk in conventional heap memory. */
 158     int contig = contiguous(&main_arena);
 159     sz = chunksize(p);
 160     if((contig &&
 161         ((char*)p<mp_.sbrk_base ||
 162          ((char*)p + sz)>=(mp_.sbrk_base+main_arena.system_mem) )) ||
 163        sz<MINSIZE || sz&MALLOC_ALIGN_MASK || !inuse(p) ||
 164        ( !prev_inuse(p) && (p->prev_size&MALLOC_ALIGN_MASK ||
 165                             (contig && (char*)prev_chunk(p)<mp_.sbrk_base) ||
 166                             next_chunk(prev_chunk(p))!=p) ))
 167       return NULL;
 168     magic = MAGICBYTE(p);
 169     for(sz += SIZE_SZ-1; (c = ((unsigned char*)p)[sz]) != magic; sz -= c) {
 170       if(c<=0 || sz<(c+2*SIZE_SZ)) return NULL;
 171     }
 172   } else {
 173     unsigned long offset, page_mask = malloc_getpagesize-1;
 174
 175     /* mmap()ed chunks have MALLOC_ALIGNMENT or higher power-of-two
 176        alignment relative to the beginning of a page.  Check this
 177        first. */
 178     offset = (unsigned long)mem & page_mask;
 179     if((offset!=MALLOC_ALIGNMENT && offset!=0 && offset!=0x10 &&
 180         offset!=0x20 && offset!=0x40 && offset!=0x80 && offset!=0x100 &&
 181         offset!=0x200 && offset!=0x400 && offset!=0x800 && offset!=0x1000 &&
 182         offset<0x2000) ||
 183        !chunk_is_mmapped(p) || (p->size & PREV_INUSE) ||
 184        ( (((unsigned long)p - p->prev_size) & page_mask) != 0 ) ||
 185        ( (sz = chunksize(p)), ((p->prev_size + sz) & page_mask) != 0 ) )
 186       return NULL;
 187     magic = MAGICBYTE(p);
 188     for(sz -= 1; (c = ((unsigned char*)p)[sz]) != magic; sz -= c) {
 189       if(c<=0 || sz<(c+2*SIZE_SZ)) return NULL;
 190     }
 191   }
 192   ((unsigned char*)p)[sz] ^= 0xFF;
 193   if (magic_p)
 194     *magic_p = (unsigned char *)p + sz;
 195   return p;
 196 }
 197
 198 /* Check for corruption of the top chunk, and try to recover if
 199    necessary. */
 200
 201 static int
 202 internal_function
 203 #if __STD_C
 204 top_check(void)
 205 #else
 206 top_check()
 207 #endif
 208 {
 209   mchunkptr t = top(&main_arena);
 210   char* brk, * new_brk;
 211   INTERNAL_SIZE_T front_misalign, sbrk_size;
 212   unsigned long pagesz = malloc_getpagesize;
 213
 214   if (t == initial_top(&main_arena) ||
 215       (!chunk_is_mmapped(t) &&
 216        chunksize(t)>=MINSIZE &&
 217        prev_inuse(t) &&
 218        (!contiguous(&main_arena) ||
 219         (char*)t + chunksize(t) == mp_.sbrk_base + main_arena.system_mem)))
 220     return 0;
 221
 222   malloc_printerr (check_action, "malloc: top chunk is corrupt", t);
 223
 224   /* Try to set up a new top chunk. */
 225   brk = MORECORE(0);
 226   front_misalign = (unsigned long)chunk2mem(brk) & MALLOC_ALIGN_MASK;
 227   if (front_misalign > 0)
 228     front_misalign = MALLOC_ALIGNMENT - front_misalign;
 229   sbrk_size = front_misalign + mp_.top_pad + MINSIZE;
 230   sbrk_size += pagesz - ((unsigned long)(brk + sbrk_size) & (pagesz - 1));
 231   new_brk = (char*)(MORECORE (sbrk_size));
 232   if (new_brk == (char*)(MORECORE_FAILURE))
 233     {
 234       MALLOC_FAILURE_ACTION;
 235       return -1;
 236     }
 237   /* Call the `morecore' hook if necessary.  */
 238   if (__after_morecore_hook)
 239     (*__after_morecore_hook) ();
 240   main_arena.system_mem = (new_brk - mp_.sbrk_base) + sbrk_size;
 241
 242   top(&main_arena) = (mchunkptr)(brk + front_misalign);
 243   set_head(top(&main_arena), (sbrk_size - front_misalign) | PREV_INUSE);
 244
 245   return 0;
 246 }
 247
 248 static Void_t*
 249 #if __STD_C
 250 malloc_check(size_t sz, const Void_t *caller)
 251 #else
 252 malloc_check(sz, caller) size_t sz; const Void_t *caller;
 253 #endif
 254 {
 255   Void_t *victim;
 256
 257   if (sz+1 == 0) {
 258     MALLOC_FAILURE_ACTION;
 259     return NULL;
 260   }
 261
 262   (void)mutex_lock(&main_arena.mutex);
 263   victim = (top_check() >= 0) ? _int_malloc(&main_arena, sz+1) : NULL;
 264   (void)mutex_unlock(&main_arena.mutex);
 265   return mem2mem_check(victim, sz);
 266 }
 267
 268 static void
 269 #if __STD_C
 270 free_check(Void_t* mem, const Void_t *caller)
 271 #else
 272 free_check(mem, caller) Void_t* mem; const Void_t *caller;
 273 #endif
 274 {
 275   mchunkptr p;
 276
 277   if(!mem) return;
 278   (void)mutex_lock(&main_arena.mutex);
 279   p = mem2chunk_check(mem, NULL);
 280   if(!p) {
 281     (void)mutex_unlock(&main_arena.mutex);
 282
 283     malloc_printerr(check_action, "free(): invalid pointer", mem);
 284     return;
 285   }
 286 #if HAVE_MMAP
 287   if (chunk_is_mmapped(p)) {
 288     (void)mutex_unlock(&main_arena.mutex);
 289     munmap_chunk(p);
 290     return;
 291   }
 292 #endif
 293 #if 0 /* Erase freed memory. */
 294   memset(mem, 0, chunksize(p) - (SIZE_SZ+1));
 295 #endif
 296   _int_free(&main_arena, p);
 297   (void)mutex_unlock(&main_arena.mutex);
 298 }
 299
 300 static Void_t*
 301 #if __STD_C
 302 realloc_check(Void_t* oldmem, size_t bytes, const Void_t *caller)
 303 #else
 304 realloc_check(oldmem, bytes, caller)
 305      Void_t* oldmem; size_t bytes; const Void_t *caller;
 306 #endif
 307 {
 308   INTERNAL_SIZE_T nb;
 309   Void_t* newmem = 0;
 310   unsigned char *magic_p;
 311
 312   if (bytes+1 == 0) {
 313     MALLOC_FAILURE_ACTION;
 314     return NULL;
 315   }
 316   if (oldmem == 0) return malloc_check(bytes, NULL);
 317   if (bytes == 0) {
 318     free_check (oldmem, NULL);
 319     return NULL;
 320   }
 321   (void)mutex_lock(&main_arena.mutex);
 322   const mchunkptr oldp = mem2chunk_check(oldmem, &magic_p);
 323   (void)mutex_unlock(&main_arena.mutex);
 324   if(!oldp) {
 325     malloc_printerr(check_action, "realloc(): invalid pointer", oldmem);
 326     return malloc_check(bytes, NULL);
 327   }
 328   const INTERNAL_SIZE_T oldsize = chunksize(oldp);
 329
 330   checked_request2size(bytes+1, nb);
 331   (void)mutex_lock(&main_arena.mutex);
 332
 333 #if HAVE_MMAP
 334   if (chunk_is_mmapped(oldp)) {
 335 #if HAVE_MREMAP
 336     mchunkptr newp = mremap_chunk(oldp, nb);
 337     if(newp)
 338       newmem = chunk2mem(newp);
 339     else
 340 #endif
 341     {
 342       /* Note the extra SIZE_SZ overhead. */
 343       if(oldsize - SIZE_SZ >= nb)
 344         newmem = oldmem; /* do nothing */
 345       else {
 346         /* Must alloc, copy, free. */
 347         if (top_check() >= 0)
 348           newmem = _int_malloc(&main_arena, bytes+1);
 349         if (newmem) {
 350           MALLOC_COPY(BOUNDED_N(newmem, bytes+1), oldmem, oldsize - 2*SIZE_SZ);
 351           munmap_chunk(oldp);
 352         }
 353       }
 354     }
 355   } else {
 356 #endif /* HAVE_MMAP */
 357     if (top_check() >= 0) {
 358       INTERNAL_SIZE_T nb;
 359       checked_request2size(bytes + 1, nb);
 360       newmem = _int_realloc(&main_arena, oldp, nb);
 361     }
 362 #if 0 /* Erase freed memory. */
 363     if(newmem)
 364       newp = mem2chunk(newmem);
 365     nb = chunksize(newp);
 366     if(oldp<newp || oldp>=chunk_at_offset(newp, nb)) {
 367       memset((char*)oldmem + 2*sizeof(mbinptr), 0,
 368              oldsize - (2*sizeof(mbinptr)+2*SIZE_SZ+1));
 369     } else if(nb > oldsize+SIZE_SZ) {
 370       memset((char*)BOUNDED_N(chunk2mem(newp), bytes) + oldsize,
 371              0, nb - (oldsize+SIZE_SZ));
 372     }
 373 #endif
 374 #if HAVE_MMAP
 375   }
 376 #endif
 377
 378   /* mem2chunk_check changed the magic byte in the old chunk.
 379      If newmem is NULL, then the old chunk will still be used though,
 380      so we need to invert that change here.  */
 381   if (newmem == NULL) *magic_p ^= 0xFF;
 382
 383   (void)mutex_unlock(&main_arena.mutex);
 384
 385   return mem2mem_check(newmem, bytes);
 386 }
 387
 388 static Void_t*
 389 #if __STD_C
 390 memalign_check(size_t alignment, size_t bytes, const Void_t *caller)
 391 #else
 392 memalign_check(alignment, bytes, caller)
 393      size_t alignment; size_t bytes; const Void_t *caller;
 394 #endif
 395 {
 396   INTERNAL_SIZE_T nb;
 397   Void_t* mem;
 398
 399   if (alignment <= MALLOC_ALIGNMENT) return malloc_check(bytes, NULL);
 400   if (alignment <  MINSIZE) alignment = MINSIZE;
 401
 402   if (bytes+1 == 0) {
 403     MALLOC_FAILURE_ACTION;
 404     return NULL;
 405   }
 406   checked_request2size(bytes+1, nb);
 407   (void)mutex_lock(&main_arena.mutex);
 408   mem = (top_check() >= 0) ? _int_memalign(&main_arena, alignment, bytes+1) :
 409     NULL;
 410   (void)mutex_unlock(&main_arena.mutex);
 411   return mem2mem_check(mem, bytes);
 412 }
 413
 414 #ifndef NO_THREADS
 415
 416 # ifdef _LIBC
 417 #  if USE___THREAD || !defined SHARED
 418     /* These routines are never needed in this configuration.  */
 419 #   define NO_STARTER
 420 #  endif
 421 # endif
 422
 423 # ifdef NO_STARTER
 424 #  undef NO_STARTER
 425 # else
 426
 427 /* The following hooks are used when the global initialization in
 428    ptmalloc_init() hasn't completed yet. */
 429
 430 static Void_t*
 431 #if __STD_C
 432 malloc_starter(size_t sz, const Void_t *caller)
 433 #else
 434 malloc_starter(sz, caller) size_t sz; const Void_t *caller;
 435 #endif
 436 {
 437   Void_t* victim;
 438
 439   victim = _int_malloc(&main_arena, sz);
 440
 441   return victim ? BOUNDED_N(victim, sz) : 0;
 442 }
 443
 444 static Void_t*
 445 #if __STD_C
 446 memalign_starter(size_t align, size_t sz, const Void_t *caller)
 447 #else
 448 memalign_starter(align, sz, caller) size_t align, sz; const Void_t *caller;
 449 #endif
 450 {
 451   Void_t* victim;
 452
 453   victim = _int_memalign(&main_arena, align, sz);
 454
 455   return victim ? BOUNDED_N(victim, sz) : 0;
 456 }
 457
 458 static void
 459 #if __STD_C
 460 free_starter(Void_t* mem, const Void_t *caller)
 461 #else
 462 free_starter(mem, caller) Void_t* mem; const Void_t *caller;
 463 #endif
 464 {
 465   mchunkptr p;
 466
 467   if(!mem) return;
 468   p = mem2chunk(mem);
 469 #if HAVE_MMAP
 470   if (chunk_is_mmapped(p)) {
 471     munmap_chunk(p);
 472     return;
 473   }
 474 #endif
 475   _int_free(&main_arena, p);
 476 }
 477
 478 # endif /* !defiend NO_STARTER */
 479 #endif /* NO_THREADS */
 480
 481
 482 /* Get/set state: malloc_get_state() records the current state of all
 483    malloc variables (_except_ for the actual heap contents and `hook'
 484    function pointers) in a system dependent, opaque data structure.
 485    This data structure is dynamically allocated and can be free()d
 486    after use.  malloc_set_state() restores the state of all malloc
 487    variables to the previously obtained state.  This is especially
 488    useful when using this malloc as part of a shared library, and when
 489    the heap contents are saved/restored via some other method.  The
 490    primary example for this is GNU Emacs with its `dumping' procedure.
 491    `Hook' function pointers are never saved or restored by these
 492    functions, with two exceptions: If malloc checking was in use when
 493    malloc_get_state() was called, then malloc_set_state() calls
 494    __malloc_check_init() if possible; if malloc checking was not in
 495    use in the recorded state but the user requested malloc checking,
 496    then the hooks are reset to 0.  */
 497
 498 #define MALLOC_STATE_MAGIC   0x444c4541l
 499 #define MALLOC_STATE_VERSION (0*0x100l + 3l) /* major*0x100 + minor */
 500
 501 struct malloc_save_state {
 502   long          magic;
 503   long          version;
 504   mbinptr       av[NBINS * 2 + 2];
 505   char*         sbrk_base;
 506   int           sbrked_mem_bytes;
 507   unsigned long trim_threshold;
 508   unsigned long top_pad;
 509   unsigned int  n_mmaps_max;
 510   unsigned long mmap_threshold;
 511   int           check_action;
 512   unsigned long max_sbrked_mem;
 513   unsigned long max_total_mem;
 514   unsigned int  n_mmaps;
 515   unsigned int  max_n_mmaps;
 516   unsigned long mmapped_mem;
 517   unsigned long max_mmapped_mem;
 518   int           using_malloc_checking;
 519 };
 520
 521 Void_t*
 522 public_gET_STATe(void)
 523 {
 524   struct malloc_save_state* ms;
 525   int i;
 526   mbinptr b;
 527
 528   ms = (struct malloc_save_state*)public_mALLOc(sizeof(*ms));
 529   if (!ms)
 530     return 0;
 531   (void)mutex_lock(&main_arena.mutex);
 532   malloc_consolidate(&main_arena);
 533   ms->magic = MALLOC_STATE_MAGIC;
 534   ms->version = MALLOC_STATE_VERSION;
 535   ms->av[0] = 0;
 536   ms->av[1] = 0; /* used to be binblocks, now no longer used */
 537   ms->av[2] = top(&main_arena);
 538   ms->av[3] = 0; /* used to be undefined */
 539   for(i=1; i<NBINS; i++) {
 540     b = bin_at(&main_arena, i);
 541     if(first(b) == b)
 542       ms->av[2*i+2] = ms->av[2*i+3] = 0; /* empty bin */
 543     else {
 544       ms->av[2*i+2] = first(b);
 545       ms->av[2*i+3] = last(b);
 546     }
 547   }
 548   ms->sbrk_base = mp_.sbrk_base;
 549   ms->sbrked_mem_bytes = main_arena.system_mem;
 550   ms->trim_threshold = mp_.trim_threshold;
 551   ms->top_pad = mp_.top_pad;
 552   ms->n_mmaps_max = mp_.n_mmaps_max;
 553   ms->mmap_threshold = mp_.mmap_threshold;
 554   ms->check_action = check_action;
 555   ms->max_sbrked_mem = main_arena.max_system_mem;
 556 #ifdef NO_THREADS
 557   ms->max_total_mem = mp_.max_total_mem;
 558 #else
 559   ms->max_total_mem = 0;
 560 #endif
 561   ms->n_mmaps = mp_.n_mmaps;
 562   ms->max_n_mmaps = mp_.max_n_mmaps;
 563   ms->mmapped_mem = mp_.mmapped_mem;
 564   ms->max_mmapped_mem = mp_.max_mmapped_mem;
 565   ms->using_malloc_checking = using_malloc_checking;
 566   (void)mutex_unlock(&main_arena.mutex);
 567   return (Void_t*)ms;
 568 }
 569
 570 int
 571 public_sET_STATe(Void_t* msptr)
 572 {
 573   struct malloc_save_state* ms = (struct malloc_save_state*)msptr;
 574   size_t i;
 575   mbinptr b;
 576
 577   disallow_malloc_check = 1;
 578   ptmalloc_init();
 579   if(ms->magic != MALLOC_STATE_MAGIC) return -1;
 580   /* Must fail if the major version is too high. */
 581   if((ms->version & ~0xffl) > (MALLOC_STATE_VERSION & ~0xffl)) return -2;
 582   (void)mutex_lock(&main_arena.mutex);
 583   /* There are no fastchunks.  */
 584   clear_fastchunks(&main_arena);
 585   set_max_fast(DEFAULT_MXFAST);
 586   for (i=0; i<NFASTBINS; ++i)
 587     main_arena.fastbins[i] = 0;
 588   for (i=0; i<BINMAPSIZE; ++i)
 589     main_arena.binmap[i] = 0;
 590   top(&main_arena) = ms->av[2];
 591   main_arena.last_remainder = 0;
 592   for(i=1; i<NBINS; i++) {
 593     b = bin_at(&main_arena, i);
 594     if(ms->av[2*i+2] == 0) {
 595       assert(ms->av[2*i+3] == 0);
 596       first(b) = last(b) = b;
 597     } else {
 598       if(ms->version >= 3 &&
 599          (i<NSMALLBINS || (largebin_index(chunksize(ms->av[2*i+2]))==i &&
 600                            largebin_index(chunksize(ms->av[2*i+3]))==i))) {
 601         first(b) = ms->av[2*i+2];
 602         last(b) = ms->av[2*i+3];
 603         /* Make sure the links to the bins within the heap are correct.  */
 604         first(b)->bk = b;
 605         last(b)->fd = b;
 606         /* Set bit in binblocks.  */
 607         mark_bin(&main_arena, i);
 608       } else {
 609         /* Oops, index computation from chunksize must have changed.
 610            Link the whole list into unsorted_chunks.  */
 611         first(b) = last(b) = b;
 612         b = unsorted_chunks(&main_arena);
 613         ms->av[2*i+2]->bk = b;
 614         ms->av[2*i+3]->fd = b->fd;
 615         b->fd->bk = ms->av[2*i+3];
 616         b->fd = ms->av[2*i+2];
 617       }
 618     }
 619   }
 620   if (ms->version < 3) {
 621     /* Clear fd_nextsize and bk_nextsize fields.  */
 622     b = unsorted_chunks(&main_arena)->fd;
 623     while (b != unsorted_chunks(&main_arena)) {
 624       if (!in_smallbin_range(chunksize(b))) {
 625         b->fd_nextsize = NULL;
 626         b->bk_nextsize = NULL;
 627       }
 628       b = b->fd;
 629     }
 630   }
 631   mp_.sbrk_base = ms->sbrk_base;
 632   main_arena.system_mem = ms->sbrked_mem_bytes;
 633   mp_.trim_threshold = ms->trim_threshold;
 634   mp_.top_pad = ms->top_pad;
 635   mp_.n_mmaps_max = ms->n_mmaps_max;
 636   mp_.mmap_threshold = ms->mmap_threshold;
 637   check_action = ms->check_action;
 638   main_arena.max_system_mem = ms->max_sbrked_mem;
 639 #ifdef NO_THREADS
 640   mp_.max_total_mem = ms->max_total_mem;
 641 #endif
 642   mp_.n_mmaps = ms->n_mmaps;
 643   mp_.max_n_mmaps = ms->max_n_mmaps;
 644   mp_.mmapped_mem = ms->mmapped_mem;
 645   mp_.max_mmapped_mem = ms->max_mmapped_mem;
 646   /* add version-dependent code here */
 647   if (ms->version >= 1) {
 648     /* Check whether it is safe to enable malloc checking, or whether
 649        it is necessary to disable it.  */
 650     if (ms->using_malloc_checking && !using_malloc_checking &&
 651         !disallow_malloc_check)
 652       __malloc_check_init ();
 653     else if (!ms->using_malloc_checking && using_malloc_checking) {
 654       __malloc_hook = 0;
 655       __free_hook = 0;
 656       __realloc_hook = 0;
 657       __memalign_hook = 0;
 658       using_malloc_checking = 0;
 659     }
 660   }
 661   check_malloc_state(&main_arena);
 662
 663   (void)mutex_unlock(&main_arena.mutex);
 664   return 0;
 665 }
 666
 667 /*
 668  * Local variables:
 669  * c-basic-offset: 2
 670  * End:
 671  */