libexec/ld.elf_so/xmalloc.c

   1 /*      $NetBSD: xmalloc.c,v 1.8 2008/06/03 19:22:07 ad Exp $   */
   2
   3 /*
   4  * Copyright 1996 John D. Polstra.
   5  * Copyright 1996 Matt Thomas <matt@3am-software.com>
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by John Polstra.
  19  * 4. The name of the author may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 /*
  35  * Copyright (c) 1983 Regents of the University of California.
  36  * All rights reserved.
  37  *
  38  * Redistribution and use in source and binary forms, with or without
  39  * modification, are permitted provided that the following conditions
  40  * are met:
  41  * 1. Redistributions of source code must retain the above copyright
  42  *    notice, this list of conditions and the following disclaimer.
  43  * 2. Redistributions in binary form must reproduce the above copyright
  44  *    notice, this list of conditions and the following disclaimer in the
  45  *    documentation and/or other materials provided with the distribution.
  46  * 3. Neither the name of the University nor the names of its contributors
  47  *    may be used to endorse or promote products derived from this software
  48  *    without specific prior written permission.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  60  * SUCH DAMAGE.
  61  */
  62
  63 #if defined(LIBC_SCCS) && !defined(lint)
  64 /*static char *sccsid = "from: @(#)malloc.c     5.11 (Berkeley) 2/23/91";*/
  65 #endif /* LIBC_SCCS and not lint */
  66
  67 /*
  68  * malloc.c (Caltech) 2/21/82
  69  * Chris Kingsley, kingsley@cit-20.
  70  *
  71  * This is a very fast storage allocator.  It allocates blocks of a small
  72  * number of different sizes, and keeps free lists of each size.  Blocks that
  73  * don't exactly fit are passed up to the next larger size.  In this
  74  * implementation, the available sizes are 2^n-4 (or 2^n-10) bytes long.
  75  * This is designed for use in a virtual memory environment.
  76  */
  77
  78 #include <sys/cdefs.h>
  79 #ifndef lint
  80 __RCSID("$NetBSD: xmalloc.c,v 1.8 2008/06/03 19:22:07 ad Exp $");
  81 #endif /* not lint */
  82
  83 #include <stdlib.h>
  84 #include <string.h>
  85 #include <unistd.h>
  86 #include <errno.h>
  87
  88 #include <sys/types.h>
  89 #include <sys/param.h>
  90 #include <sys/mman.h>
  91 #include <sys/stat.h>
  92
  93 #include "rtld.h"
  94
  95 /*
  96  * Pre-allocate mmap'ed pages
  97  */
  98 #define NPOOLPAGES      (32*1024/pagesz)
  99 static char             *pagepool_start, *pagepool_end;
 100 static int              morepages(int);
 101 #define PAGEPOOL_SIZE   (size_t)(pagepool_end - pagepool_start)
 102
 103 /*
 104  * The overhead on a block is at least 4 bytes.  When free, this space
 105  * contains a pointer to the next free block, and the bottom two bits must
 106  * be zero.  When in use, the first byte is set to MAGIC, and the second
 107  * byte is the size index.  The remaining bytes are for alignment.
 108  * If range checking is enabled then a second word holds the size of the
 109  * requested block, less 1, rounded up to a multiple of sizeof(RMAGIC).
 110  * The order of elements is critical: ov_magic must overlay the low order
 111  * bits of ov_next, and ov_magic can not be a valid ov_next bit pattern.
 112  */
 113 union   overhead {
 114         union   overhead *ov_next;      /* when free */
 115         struct {
 116                 u_char  ovu_magic;      /* magic number */
 117                 u_char  ovu_index;      /* bucket # */
 118 #ifdef RCHECK
 119                 u_short ovu_rmagic;     /* range magic number */
 120                 u_int   ovu_size;       /* actual block size */
 121 #endif
 122         } ovu;
 123 #define ov_magic        ovu.ovu_magic
 124 #define ov_index        ovu.ovu_index
 125 #define ov_rmagic       ovu.ovu_rmagic
 126 #define ov_size         ovu.ovu_size
 127 };
 128
 129 static void morecore(size_t);
 130 static void *imalloc(size_t);
 131
 132 #define MAGIC           0xef            /* magic # on accounting info */
 133 #define RMAGIC          0x5555          /* magic # on range info */
 134
 135 #ifdef RCHECK
 136 #define RSLOP           (sizeof (u_short))
 137 #else
 138 #define RSLOP           0
 139 #endif
 140
 141 /*
 142  * nextf[i] is the pointer to the next free block of size 2^(i+3).  The
 143  * smallest allocatable block is 8 bytes.  The overhead information
 144  * precedes the data area returned to the user.
 145  */
 146 #define NBUCKETS 30
 147 static  union overhead *nextf[NBUCKETS];
 148
 149 static  size_t pagesz;                  /* page size */
 150 static  size_t pagebucket;              /* page size bucket */
 151
 152 #ifdef MSTATS
 153 /*
 154  * nmalloc[i] is the difference between the number of mallocs and frees
 155  * for a given block size.
 156  */
 157 static  u_int nmalloc[NBUCKETS];
 158 #endif
 159
 160 #if defined(MALLOC_DEBUG) || defined(RCHECK)
 161 #define ASSERT(p)   if (!(p)) botch("p")
 162 static void
 163 botch(
 164     const char *s)
 165 {
 166     xwarnx("\r\nassertion botched: %s\r\n", s);
 167     abort();
 168 }
 169 #else
 170 #define ASSERT(p)
 171 #endif
 172
 173 #define TRACE() xprintf("TRACE %s:%d\n", __FILE__, __LINE__)
 174
 175 static void *
 176 imalloc(size_t nbytes)
 177 {
 178         union overhead *op;
 179         size_t bucket;
 180         size_t n, m;
 181         unsigned amt;
 182
 183         /*
 184          * First time malloc is called, setup page size and
 185          * align break pointer so all data will be page aligned.
 186          */
 187         if (pagesz == 0) {
 188                 pagesz = n = _rtld_pagesz;
 189                 if (morepages(NPOOLPAGES) == 0)
 190                         return NULL;
 191                 op = (union overhead *)(pagepool_start);
 192                 m = sizeof (*op) - (((char *)op - (char *)NULL) & (n - 1));
 193                 if (n < m)
 194                         n += pagesz - m;
 195                 else
 196                         n -= m;
 197                 if (n) {
 198                         pagepool_start += n;
 199                 }
 200                 bucket = 0;
 201                 amt = sizeof(union overhead);
 202                 while (pagesz > amt) {
 203                         amt <<= 1;
 204                         bucket++;
 205                 }
 206                 pagebucket = bucket;
 207         }
 208         /*
 209          * Convert amount of memory requested into closest block size
 210          * stored in hash buckets which satisfies request.
 211          * Account for space used per block for accounting.
 212          */
 213         if (nbytes <= (n = pagesz - sizeof (*op) - RSLOP)) {
 214                 if (sizeof(union overhead) & (sizeof(union overhead) - 1)) {
 215                     amt = sizeof(union overhead) * 2;
 216                     bucket = 1;
 217                 } else {
 218                     amt = sizeof(union overhead); /* size of first bucket */
 219                     bucket = 0;
 220                 }
 221                 n = -(sizeof (*op) + RSLOP);
 222         } else {
 223                 amt = pagesz;
 224                 bucket = pagebucket;
 225         }
 226         while (nbytes > amt + n) {
 227                 amt <<= 1;
 228                 if (amt == 0)
 229                         return (NULL);
 230                 bucket++;
 231         }
 232         /*
 233          * If nothing in hash bucket right now,
 234          * request more memory from the system.
 235          */
 236         if ((op = nextf[bucket]) == NULL) {
 237                 morecore(bucket);
 238                 if ((op = nextf[bucket]) == NULL)
 239                         return (NULL);
 240         }
 241         /* remove from linked list */
 242         nextf[bucket] = op->ov_next;
 243         op->ov_magic = MAGIC;
 244         op->ov_index = bucket;
 245 #ifdef MSTATS
 246         nmalloc[bucket]++;
 247 #endif
 248 #ifdef RCHECK
 249         /*
 250          * Record allocated size of block and
 251          * bound space with magic numbers.
 252          */
 253         op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
 254         op->ov_rmagic = RMAGIC;
 255         *(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
 256 #endif
 257         return ((char *)(op + 1));
 258 }
 259
 260 /*
 261  * Allocate more memory to the indicated bucket.
 262  */
 263 static void
 264 morecore(size_t bucket)
 265 {
 266         union overhead *op;
 267         size_t sz;              /* size of desired block */
 268         size_t amt;             /* amount to allocate */
 269         size_t nblks;           /* how many blocks we get */
 270
 271         /*
 272          * sbrk_size <= 0 only for big, FLUFFY, requests (about
 273          * 2^30 bytes on a VAX, I think) or for a negative arg.
 274          */
 275         sz = 1 << (bucket + 3);
 276 #ifdef MALLOC_DEBUG
 277         ASSERT(sz > 0);
 278 #endif
 279         if (sz < pagesz) {
 280                 amt = pagesz;
 281                 nblks = amt / sz;
 282         } else {
 283                 amt = sz + pagesz;
 284                 nblks = 1;
 285         }
 286         if (amt > PAGEPOOL_SIZE)
 287                 if (morepages(amt/pagesz + NPOOLPAGES) == 0)
 288                         return;
 289         op = (union overhead *)pagepool_start;
 290         pagepool_start += amt;
 291
 292         /*
 293          * Add new memory allocated to that on
 294          * free list for this hash bucket.
 295          */
 296         nextf[bucket] = op;
 297         while (--nblks > 0) {
 298                 op->ov_next = (union overhead *)((caddr_t)op + sz);
 299                 op = (union overhead *)((caddr_t)op + sz);
 300         }
 301 }
 302
 303 void
 304 xfree(cp)
 305         void *cp;
 306 {
 307         int size;
 308         union overhead *op;
 309
 310         if (cp == NULL)
 311                 return;
 312         op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
 313 #ifdef MALLOC_DEBUG
 314         ASSERT(op->ov_magic == MAGIC);          /* make sure it was in use */
 315 #else
 316         if (op->ov_magic != MAGIC)
 317                 return;                         /* sanity */
 318 #endif
 319 #ifdef RCHECK
 320         ASSERT(op->ov_rmagic == RMAGIC);
 321         ASSERT(*(u_short *)((caddr_t)(op + 1) + op->ov_size) == RMAGIC);
 322 #endif
 323         size = op->ov_index;
 324         ASSERT(size < NBUCKETS);
 325         op->ov_next = nextf[size];      /* also clobbers ov_magic */
 326         nextf[size] = op;
 327 #ifdef MSTATS
 328         nmalloc[size]--;
 329 #endif
 330 }
 331
 332 static void *
 333 irealloc(void *cp, size_t nbytes)
 334 {
 335         size_t onb;
 336         size_t i;
 337         union overhead *op;
 338         char *res;
 339
 340         if (cp == NULL)
 341                 return (imalloc(nbytes));
 342         op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
 343         if (op->ov_magic != MAGIC) {
 344                 static const char *err_str =
 345                     "memory corruption or double free in realloc\n";
 346                 extern char *__progname;
 347                 write(STDERR_FILENO, __progname, strlen(__progname));
 348                 write(STDERR_FILENO, err_str, strlen(err_str));
 349                 abort();
 350         }
 351
 352         i = op->ov_index;
 353         onb = 1 << (i + 3);
 354         if (onb < pagesz)
 355                 onb -= sizeof (*op) + RSLOP;
 356         else
 357                 onb += pagesz - sizeof (*op) - RSLOP;
 358         /* avoid the copy if same size block */
 359         if (i) {
 360                 i = 1 << (i + 2);
 361                 if (i < pagesz)
 362                         i -= sizeof (*op) + RSLOP;
 363                 else
 364                         i += pagesz - sizeof (*op) - RSLOP;
 365         }
 366         if (nbytes <= onb && nbytes > i) {
 367 #ifdef RCHECK
 368                 op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
 369                 *(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
 370 #endif
 371                 return(cp);
 372         } else
 373                 xfree(cp);
 374         if ((res = imalloc(nbytes)) == NULL)
 375                 return (NULL);
 376         if (cp != res)          /* common optimization if "compacting" */
 377                 memcpy(res, cp, (nbytes < onb) ? nbytes : onb);
 378         return (res);
 379 }
 380
 381 #ifdef MSTATS
 382 /*
 383  * mstats - print out statistics about malloc
 384  *
 385  * Prints two lines of numbers, one showing the length of the free list
 386  * for each size category, the second showing the number of mallocs -
 387  * frees for each size category.
 388  */
 389 mstats(char *s)
 390 {
 391         int i, j;
 392         union overhead *p;
 393         int totfree = 0,
 394         totused = 0;
 395
 396         xprintf("Memory allocation statistics %s\nfree:\t", s);
 397         for (i = 0; i < NBUCKETS; i++) {
 398                 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
 399                         ;
 400                 xprintf(" %d", j);
 401                 totfree += j * (1 << (i + 3));
 402         }
 403         xprintf("\nused:\t");
 404         for (i = 0; i < NBUCKETS; i++) {
 405                 xprintf(" %d", nmalloc[i]);
 406                 totused += nmalloc[i] * (1 << (i + 3));
 407         }
 408         xprintf("\n\tTotal in use: %d, total free: %d\n",
 409             totused, totfree);
 410 }
 411 #endif
 412
 413
 414 static int
 415 morepages(int n)
 416 {
 417         int     fd = -1;
 418         int     offset;
 419
 420 #ifdef NEED_DEV_ZERO
 421         fd = open("/dev/zero", O_RDWR, 0);
 422         if (fd == -1)
 423                 xerr(1, "/dev/zero");
 424 #endif
 425
 426         if (PAGEPOOL_SIZE > pagesz) {
 427                 caddr_t addr = (caddr_t)
 428                         (((long)pagepool_start + pagesz - 1) & ~(pagesz - 1));
 429                 if (munmap(addr, pagepool_end - addr) != 0)
 430                         xwarn("morepages: munmap %p", addr);
 431         }
 432
 433         offset = (long)pagepool_start - ((long)pagepool_start & ~(pagesz - 1));
 434
 435         if ((pagepool_start = mmap(0, n * pagesz,
 436                         PROT_READ|PROT_WRITE,
 437                         MAP_ANON|MAP_PRIVATE, fd, 0)) == (caddr_t)-1) {
 438                 xprintf("Cannot map anonymous memory");
 439                 return 0;
 440         }
 441         pagepool_end = pagepool_start + n * pagesz;
 442         pagepool_start += offset;
 443
 444 #ifdef NEED_DEV_ZERO
 445         close(fd);
 446 #endif
 447         return n;
 448 }
 449
 450 void *
 451 xcalloc(size_t size)
 452 {
 453
 454         return memset(xmalloc(size), 0, size);
 455 }
 456
 457 void *
 458 xmalloc(size_t size)
 459 {
 460         void *p = imalloc(size);
 461
 462         if (p == NULL)
 463                 xerr(1, "%s", xstrerror(errno));
 464         return p;
 465 }
 466
 467 void *
 468 xrealloc(void *p, size_t size)
 469 {
 470         p = irealloc(p, size);
 471
 472         if (p == NULL)
 473                 xerr(1, "%s", xstrerror(errno));
 474         return p;
 475 }
 476
 477 char *
 478 xstrdup(const char *str)
 479 {
 480         size_t len;
 481         char *copy;
 482
 483         len = strlen(str) + 1;
 484         copy = xmalloc(len);
 485         memcpy(copy, str, len);
 486         return (copy);
 487 }