libexec/ld.elf_so/xmalloc.c

   1 /*      $NetBSD: xmalloc.c,v 1.10 2010/12/03 23:07:49 joerg 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 #ifdef __minix
  64 #define munmap minix_munmap
  65 #endif
  66
  67 #if defined(LIBC_SCCS) && !defined(lint)
  68 /*static char *sccsid = "from: @(#)malloc.c     5.11 (Berkeley) 2/23/91";*/
  69 #endif /* LIBC_SCCS and not lint */
  70
  71 /*
  72  * malloc.c (Caltech) 2/21/82
  73  * Chris Kingsley, kingsley@cit-20.
  74  *
  75  * This is a very fast storage allocator.  It allocates blocks of a small
  76  * number of different sizes, and keeps free lists of each size.  Blocks that
  77  * don't exactly fit are passed up to the next larger size.  In this
  78  * implementation, the available sizes are 2^n-4 (or 2^n-10) bytes long.
  79  * This is designed for use in a virtual memory environment.
  80  */
  81
  82 #include <sys/cdefs.h>
  83 #ifndef lint
  84 __RCSID("$NetBSD: xmalloc.c,v 1.10 2010/12/03 23:07:49 joerg Exp $");
  85 #endif /* not lint */
  86
  87 #include <stdlib.h>
  88 #include <string.h>
  89 #include <unistd.h>
  90 #include <errno.h>
  91
  92 #include <sys/types.h>
  93 #include <sys/param.h>
  94 #include <sys/mman.h>
  95 #include <sys/stat.h>
  96
  97 #include "rtld.h"
  98
  99 /*
 100  * Pre-allocate mmap'ed pages
 101  */
 102 #define NPOOLPAGES      (32*1024/pagesz)
 103 static char             *pagepool_start, *pagepool_end;
 104 static int              morepages(int);
 105 #define PAGEPOOL_SIZE   (size_t)(pagepool_end - pagepool_start)
 106
 107 /*
 108  * The overhead on a block is at least 4 bytes.  When free, this space
 109  * contains a pointer to the next free block, and the bottom two bits must
 110  * be zero.  When in use, the first byte is set to MAGIC, and the second
 111  * byte is the size index.  The remaining bytes are for alignment.
 112  * If range checking is enabled then a second word holds the size of the
 113  * requested block, less 1, rounded up to a multiple of sizeof(RMAGIC).
 114  * The order of elements is critical: ov_magic must overlay the low order
 115  * bits of ov_next, and ov_magic can not be a valid ov_next bit pattern.
 116  */
 117 union   overhead {
 118         union   overhead *ov_next;      /* when free */
 119         struct {
 120                 u_char  ovu_magic;      /* magic number */
 121                 u_char  ovu_index;      /* bucket # */
 122 #ifdef RCHECK
 123                 u_short ovu_rmagic;     /* range magic number */
 124                 u_int   ovu_size;       /* actual block size */
 125 #endif
 126         } ovu;
 127 #define ov_magic        ovu.ovu_magic
 128 #define ov_index        ovu.ovu_index
 129 #define ov_rmagic       ovu.ovu_rmagic
 130 #define ov_size         ovu.ovu_size
 131 };
 132
 133 static void morecore(size_t);
 134 static void *imalloc(size_t);
 135
 136 #define MAGIC           0xef            /* magic # on accounting info */
 137 #define RMAGIC          0x5555          /* magic # on range info */
 138
 139 #ifdef RCHECK
 140 #define RSLOP           (sizeof (u_short))
 141 #else
 142 #define RSLOP           0
 143 #endif
 144
 145 /*
 146  * nextf[i] is the pointer to the next free block of size 2^(i+3).  The
 147  * smallest allocatable block is 8 bytes.  The overhead information
 148  * precedes the data area returned to the user.
 149  */
 150 #define NBUCKETS 30
 151 static  union overhead *nextf[NBUCKETS];
 152
 153 static  size_t pagesz;                  /* page size */
 154 static  size_t pagebucket;              /* page size bucket */
 155
 156 #ifdef MSTATS
 157 /*
 158  * nmalloc[i] is the difference between the number of mallocs and frees
 159  * for a given block size.
 160  */
 161 static  u_int nmalloc[NBUCKETS];
 162 #endif
 163
 164 #if defined(MALLOC_DEBUG) || defined(RCHECK)
 165 #define ASSERT(p)   if (!(p)) botch("p")
 166 static void
 167 botch(const char *s)
 168 {
 169     xwarnx("\r\nassertion botched: %s\r\n", s);
 170     abort();
 171 }
 172 #else
 173 #define ASSERT(p)
 174 #endif
 175
 176 #define TRACE() xprintf("TRACE %s:%d\n", __FILE__, __LINE__)
 177
 178 static void *
 179 imalloc(size_t nbytes)
 180 {
 181         union overhead *op;
 182         size_t bucket;
 183         size_t n, m;
 184         unsigned amt;
 185
 186         /*
 187          * First time malloc is called, setup page size and
 188          * align break pointer so all data will be page aligned.
 189          */
 190         if (pagesz == 0) {
 191                 pagesz = n = _rtld_pagesz;
 192                 if (morepages(NPOOLPAGES) == 0)
 193                         return NULL;
 194                 op = (union overhead *)(pagepool_start);
 195                 m = sizeof (*op) - (((char *)op - (char *)NULL) & (n - 1));
 196                 if (n < m)
 197                         n += pagesz - m;
 198                 else
 199                         n -= m;
 200                 if (n) {
 201                         pagepool_start += n;
 202                 }
 203                 bucket = 0;
 204                 amt = sizeof(union overhead);
 205                 while (pagesz > amt) {
 206                         amt <<= 1;
 207                         bucket++;
 208                 }
 209                 pagebucket = bucket;
 210         }
 211         /*
 212          * Convert amount of memory requested into closest block size
 213          * stored in hash buckets which satisfies request.
 214          * Account for space used per block for accounting.
 215          */
 216         if (nbytes <= (n = pagesz - sizeof (*op) - RSLOP)) {
 217                 if (sizeof(union overhead) & (sizeof(union overhead) - 1)) {
 218                     amt = sizeof(union overhead) * 2;
 219                     bucket = 1;
 220                 } else {
 221                     amt = sizeof(union overhead); /* size of first bucket */
 222                     bucket = 0;
 223                 }
 224                 n = -(sizeof (*op) + RSLOP);
 225         } else {
 226                 amt = pagesz;
 227                 bucket = pagebucket;
 228         }
 229         while (nbytes > amt + n) {
 230                 amt <<= 1;
 231                 if (amt == 0)
 232                         return (NULL);
 233                 bucket++;
 234         }
 235         /*
 236          * If nothing in hash bucket right now,
 237          * request more memory from the system.
 238          */
 239         if ((op = nextf[bucket]) == NULL) {
 240                 morecore(bucket);
 241                 if ((op = nextf[bucket]) == NULL)
 242                         return (NULL);
 243         }
 244         /* remove from linked list */
 245         nextf[bucket] = op->ov_next;
 246         op->ov_magic = MAGIC;
 247         op->ov_index = bucket;
 248 #ifdef MSTATS
 249         nmalloc[bucket]++;
 250 #endif
 251 #ifdef RCHECK
 252         /*
 253          * Record allocated size of block and
 254          * bound space with magic numbers.
 255          */
 256         op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
 257         op->ov_rmagic = RMAGIC;
 258         *(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
 259 #endif
 260         return ((char *)(op + 1));
 261 }
 262
 263 /*
 264  * Allocate more memory to the indicated bucket.
 265  */
 266 static void
 267 morecore(size_t bucket)
 268 {
 269         union overhead *op;
 270         size_t sz;              /* size of desired block */
 271         size_t amt;             /* amount to allocate */
 272         size_t nblks;           /* how many blocks we get */
 273
 274         /*
 275          * sbrk_size <= 0 only for big, FLUFFY, requests (about
 276          * 2^30 bytes on a VAX, I think) or for a negative arg.
 277          */
 278         sz = 1 << (bucket + 3);
 279 #ifdef MALLOC_DEBUG
 280         ASSERT(sz > 0);
 281 #endif
 282         if (sz < pagesz) {
 283                 amt = pagesz;
 284                 nblks = amt / sz;
 285         } else {
 286                 amt = sz + pagesz;
 287                 nblks = 1;
 288         }
 289         if (amt > PAGEPOOL_SIZE)
 290                 if (morepages(amt/pagesz + NPOOLPAGES) == 0)
 291                         return;
 292         op = (union overhead *)pagepool_start;
 293         pagepool_start += amt;
 294
 295         /*
 296          * Add new memory allocated to that on
 297          * free list for this hash bucket.
 298          */
 299         nextf[bucket] = op;
 300         while (--nblks > 0) {
 301                 op->ov_next = (union overhead *)((caddr_t)op + sz);
 302                 op = (union overhead *)((caddr_t)op + sz);
 303         }
 304 }
 305
 306 void
 307 xfree(void *cp)
 308 {
 309         int size;
 310         union overhead *op;
 311
 312         if (cp == NULL)
 313                 return;
 314         op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
 315 #ifdef MALLOC_DEBUG
 316         ASSERT(op->ov_magic == MAGIC);          /* make sure it was in use */
 317 #else
 318         if (op->ov_magic != MAGIC)
 319                 return;                         /* sanity */
 320 #endif
 321 #ifdef RCHECK
 322         ASSERT(op->ov_rmagic == RMAGIC);
 323         ASSERT(*(u_short *)((caddr_t)(op + 1) + op->ov_size) == RMAGIC);
 324 #endif
 325         size = op->ov_index;
 326         ASSERT(size < NBUCKETS);
 327         op->ov_next = nextf[size];      /* also clobbers ov_magic */
 328         nextf[size] = op;
 329 #ifdef MSTATS
 330         nmalloc[size]--;
 331 #endif
 332 }
 333
 334 static void *
 335 irealloc(void *cp, size_t nbytes)
 336 {
 337         size_t onb;
 338         size_t i;
 339         union overhead *op;
 340         char *res;
 341
 342         if (cp == NULL)
 343                 return (imalloc(nbytes));
 344         op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
 345         if (op->ov_magic != MAGIC) {
 346                 static const char *err_str =
 347                     "memory corruption or double free in realloc\n";
 348                 extern char *__progname;
 349                 write(STDERR_FILENO, __progname, strlen(__progname));
 350                 write(STDERR_FILENO, err_str, strlen(err_str));
 351                 abort();
 352         }
 353
 354         i = op->ov_index;
 355         onb = 1 << (i + 3);
 356         if (onb < pagesz)
 357                 onb -= sizeof (*op) + RSLOP;
 358         else
 359                 onb += pagesz - sizeof (*op) - RSLOP;
 360         /* avoid the copy if same size block */
 361         if (i) {
 362                 i = 1 << (i + 2);
 363                 if (i < pagesz)
 364                         i -= sizeof (*op) + RSLOP;
 365                 else
 366                         i += pagesz - sizeof (*op) - RSLOP;
 367         }
 368         if (nbytes <= onb && nbytes > i) {
 369 #ifdef RCHECK
 370                 op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
 371                 *(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
 372 #endif
 373                 return(cp);
 374         } else
 375                 xfree(cp);
 376         if ((res = imalloc(nbytes)) == NULL)
 377                 return (NULL);
 378         if (cp != res)          /* common optimization if "compacting" */
 379                 memcpy(res, cp, (nbytes < onb) ? nbytes : onb);
 380         return (res);
 381 }
 382
 383 #ifdef MSTATS
 384 /*
 385  * mstats - print out statistics about malloc
 386  *
 387  * Prints two lines of numbers, one showing the length of the free list
 388  * for each size category, the second showing the number of mallocs -
 389  * frees for each size category.
 390  */
 391 void
 392 mstats(char *s)
 393 {
 394         int i, j;
 395         union overhead *p;
 396         int totfree = 0,
 397         totused = 0;
 398
 399         xprintf("Memory allocation statistics %s\nfree:\t", s);
 400         for (i = 0; i < NBUCKETS; i++) {
 401                 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
 402                         ;
 403                 xprintf(" %d", j);
 404                 totfree += j * (1 << (i + 3));
 405         }
 406         xprintf("\nused:\t");
 407         for (i = 0; i < NBUCKETS; i++) {
 408                 xprintf(" %d", nmalloc[i]);
 409                 totused += nmalloc[i] * (1 << (i + 3));
 410         }
 411         xprintf("\n\tTotal in use: %d, total free: %d\n",
 412             totused, totfree);
 413 }
 414 #endif
 415
 416 /* Minix mmap can do this. */
 417 #ifdef __minix
 418 #define mmap minix_mmap
 419 #endif
 420
 421 static int
 422 morepages(int n)
 423 {
 424         int     fd = -1;
 425         int     offset;
 426
 427 #ifdef NEED_DEV_ZERO
 428         fd = open("/dev/zero", O_RDWR, 0);
 429         if (fd == -1)
 430                 xerr(1, "/dev/zero");
 431 #endif
 432
 433         if (PAGEPOOL_SIZE > pagesz) {
 434                 caddr_t addr = (caddr_t)
 435                         (((long)pagepool_start + pagesz - 1) & ~(pagesz - 1));
 436                 if (munmap(addr, pagepool_end - addr) != 0)
 437                         xwarn("morepages: munmap %p", addr);
 438         }
 439
 440         offset = (long)pagepool_start - ((long)pagepool_start & ~(pagesz - 1));
 441
 442         if ((pagepool_start = mmap(0, n * pagesz,
 443                         PROT_READ|PROT_WRITE,
 444                         MAP_ANON|MAP_PRIVATE, fd, 0)) == (caddr_t)-1) {
 445                 xprintf("Cannot map anonymous memory");
 446                 return 0;
 447         }
 448         pagepool_end = pagepool_start + n * pagesz;
 449         pagepool_start += offset;
 450
 451 #ifdef NEED_DEV_ZERO
 452         close(fd);
 453 #endif
 454         return n;
 455 }
 456
 457 void *
 458 xcalloc(size_t size)
 459 {
 460
 461         return memset(xmalloc(size), 0, size);
 462 }
 463
 464 void *
 465 xmalloc(size_t size)
 466 {
 467         void *p = imalloc(size);
 468
 469         if (p == NULL)
 470                 xerr(1, "%s", xstrerror(errno));
 471         return p;
 472 }
 473
 474 void *
 475 xrealloc(void *p, size_t size)
 476 {
 477         p = irealloc(p, size);
 478
 479         if (p == NULL)
 480                 xerr(1, "%s", xstrerror(errno));
 481         return p;
 482 }
 483
 484 char *
 485 xstrdup(const char *str)
 486 {
 487         size_t len;
 488         char *copy;
 489
 490         len = strlen(str) + 1;
 491         copy = xmalloc(len);
 492         memcpy(copy, str, len);
 493         return (copy);
 494 }