libexec/ld.elf_so/xmalloc.c

   1 /*      $NetBSD: xmalloc.c,v 1.12 2013/01/24 17:57:29 christos 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 1.12 2013/01/24 17:57:29 christos 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 static  size_t pageshift;               /* page size shift */
 152
 153 #ifdef MSTATS
 154 /*
 155  * nmalloc[i] is the difference between the number of mallocs and frees
 156  * for a given block size.
 157  */
 158 static  u_int nmalloc[NBUCKETS];
 159 #endif
 160
 161 #if defined(MALLOC_DEBUG) || defined(RCHECK)
 162 #define ASSERT(p)   if (!(p)) botch("p")
 163 static void
 164 botch(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                 pageshift = ffs(pagesz) - 1;
 208         }
 209         /*
 210          * Convert amount of memory requested into closest block size
 211          * stored in hash buckets which satisfies request.
 212          * Account for space used per block for accounting.
 213          */
 214         if (nbytes <= (n = pagesz - sizeof (*op) - RSLOP)) {
 215                 if (sizeof(union overhead) & (sizeof(union overhead) - 1)) {
 216                     amt = sizeof(union overhead) * 2;
 217                     bucket = 1;
 218                 } else {
 219                     amt = sizeof(union overhead); /* size of first bucket */
 220                     bucket = 0;
 221                 }
 222                 n = -(sizeof (*op) + RSLOP);
 223         } else {
 224                 amt = pagesz;
 225                 bucket = pagebucket;
 226         }
 227         while (nbytes > amt + n) {
 228                 amt <<= 1;
 229                 if (amt == 0)
 230                         return (NULL);
 231                 bucket++;
 232         }
 233         /*
 234          * If nothing in hash bucket right now,
 235          * request more memory from the system.
 236          */
 237         if ((op = nextf[bucket]) == NULL) {
 238                 morecore(bucket);
 239                 if ((op = nextf[bucket]) == NULL)
 240                         return (NULL);
 241         }
 242         /* remove from linked list */
 243         nextf[bucket] = op->ov_next;
 244         op->ov_magic = MAGIC;
 245         op->ov_index = bucket;
 246 #ifdef MSTATS
 247         nmalloc[bucket]++;
 248 #endif
 249 #ifdef RCHECK
 250         /*
 251          * Record allocated size of block and
 252          * bound space with magic numbers.
 253          */
 254         op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
 255         op->ov_rmagic = RMAGIC;
 256         *(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
 257 #endif
 258         return ((char *)(op + 1));
 259 }
 260
 261 /*
 262  * Allocate more memory to the indicated bucket.
 263  */
 264 static void
 265 morecore(size_t bucket)
 266 {
 267         union overhead *op;
 268         size_t sz;              /* size of desired block */
 269         size_t amt;             /* amount to allocate */
 270         size_t nblks;           /* how many blocks we get */
 271
 272         /*
 273          * sbrk_size <= 0 only for big, FLUFFY, requests (about
 274          * 2^30 bytes on a VAX, I think) or for a negative arg.
 275          */
 276         sz = 1 << (bucket + 3);
 277 #ifdef MALLOC_DEBUG
 278         ASSERT(sz > 0);
 279 #endif
 280         if (sz < pagesz) {
 281                 amt = pagesz;
 282                 nblks = amt >> (bucket + 3);
 283         } else {
 284                 amt = sz + pagesz;
 285                 nblks = 1;
 286         }
 287         if (amt > PAGEPOOL_SIZE)
 288                 if (morepages((amt >> pageshift) + NPOOLPAGES) == 0)
 289                         return;
 290         op = (union overhead *)pagepool_start;
 291         pagepool_start += amt;
 292
 293         /*
 294          * Add new memory allocated to that on
 295          * free list for this hash bucket.
 296          */
 297         nextf[bucket] = op;
 298         while (--nblks > 0) {
 299                 op->ov_next = (union overhead *)((caddr_t)op + sz);
 300                 op = (union overhead *)((caddr_t)op + sz);
 301         }
 302 }
 303
 304 void
 305 xfree(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         }
 373         if ((res = imalloc(nbytes)) == NULL)
 374                 return (NULL);
 375         if (cp != res) {        /* common optimization if "compacting" */
 376                 memcpy(res, cp, (nbytes < onb) ? nbytes : onb);
 377                 xfree(cp);
 378         }
 379         return (res);
 380 }
 381
 382 #ifdef MSTATS
 383 /*
 384  * mstats - print out statistics about malloc
 385  *
 386  * Prints two lines of numbers, one showing the length of the free list
 387  * for each size category, the second showing the number of mallocs -
 388  * frees for each size category.
 389  */
 390 void
 391 mstats(char *s)
 392 {
 393         int i, j;
 394         union overhead *p;
 395         int totfree = 0,
 396         totused = 0;
 397
 398         xprintf("Memory allocation statistics %s\nfree:\t", s);
 399         for (i = 0; i < NBUCKETS; i++) {
 400                 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
 401                         ;
 402                 xprintf(" %d", j);
 403                 totfree += j * (1 << (i + 3));
 404         }
 405         xprintf("\nused:\t");
 406         for (i = 0; i < NBUCKETS; i++) {
 407                 xprintf(" %d", nmalloc[i]);
 408                 totused += nmalloc[i] * (1 << (i + 3));
 409         }
 410         xprintf("\n\tTotal in use: %d, total free: %d\n",
 411             totused, totfree);
 412 }
 413 #endif
 414
 415
 416 static int
 417 morepages(int n)
 418 {
 419         int     fd = -1;
 420         int     offset;
 421
 422 #ifdef NEED_DEV_ZERO
 423         fd = open("/dev/zero", O_RDWR, 0);
 424         if (fd == -1)
 425                 xerr(1, "/dev/zero");
 426 #endif
 427
 428         if (PAGEPOOL_SIZE > pagesz) {
 429                 caddr_t addr = (caddr_t)
 430                         (((long)pagepool_start + pagesz - 1) & ~(pagesz - 1));
 431                 if (munmap(addr, pagepool_end - addr) != 0)
 432                         xwarn("morepages: munmap %p", addr);
 433         }
 434
 435         offset = (long)pagepool_start - ((long)pagepool_start & ~(pagesz - 1));
 436
 437         if ((pagepool_start = mmap(0, n * pagesz,
 438                         PROT_READ|PROT_WRITE,
 439                         MAP_ANON|MAP_PRIVATE, fd, 0)) == (caddr_t)-1) {
 440                 xprintf("Cannot map anonymous memory");
 441                 return 0;
 442         }
 443         pagepool_end = pagepool_start + n * pagesz;
 444         pagepool_start += offset;
 445
 446 #ifdef NEED_DEV_ZERO
 447         close(fd);
 448 #endif
 449         return n;
 450 }
 451
 452 void *
 453 xcalloc(size_t size)
 454 {
 455
 456         return memset(xmalloc(size), 0, size);
 457 }
 458
 459 void *
 460 xmalloc(size_t size)
 461 {
 462         void *p = imalloc(size);
 463
 464         if (p == NULL)
 465                 xerr(1, "%s", xstrerror(errno));
 466         return p;
 467 }
 468
 469 void *
 470 xrealloc(void *p, size_t size)
 471 {
 472         p = irealloc(p, size);
 473
 474         if (p == NULL)
 475                 xerr(1, "%s", xstrerror(errno));
 476         return p;
 477 }
 478
 479 char *
 480 xstrdup(const char *str)
 481 {
 482         size_t len;
 483         char *copy;
 484
 485         len = strlen(str) + 1;
 486         copy = xmalloc(len);
 487         memcpy(copy, str, len);
 488         return (copy);
 489 }