libexec/ld.elf_so/xmalloc.c

   1 /*      $NetBSD: xmalloc.c,v 1.11 2011/05/25 14:41:46 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 #ifdef __minix
  64 /* Minix mmap can do this. */
  65 #define mmap minix_mmap
  66 #define munmap minix_munmap
  67 #endif
  68
  69 #if defined(LIBC_SCCS) && !defined(lint)
  70 /*static char *sccsid = "from: @(#)malloc.c     5.11 (Berkeley) 2/23/91";*/
  71 #endif /* LIBC_SCCS and not lint */
  72
  73 /*
  74  * malloc.c (Caltech) 2/21/82
  75  * Chris Kingsley, kingsley@cit-20.
  76  *
  77  * This is a very fast storage allocator.  It allocates blocks of a small
  78  * number of different sizes, and keeps free lists of each size.  Blocks that
  79  * don't exactly fit are passed up to the next larger size.  In this
  80  * implementation, the available sizes are 2^n-4 (or 2^n-10) bytes long.
  81  * This is designed for use in a virtual memory environment.
  82  */
  83
  84 #include <sys/cdefs.h>
  85 #ifndef lint
  86 __RCSID("$NetBSD: xmalloc.c,v 1.11 2011/05/25 14:41:46 christos Exp $");
  87 #endif /* not lint */
  88
  89 #include <stdlib.h>
  90 #include <string.h>
  91 #include <unistd.h>
  92 #include <errno.h>
  93
  94 #include <sys/types.h>
  95 #include <sys/param.h>
  96 #include <sys/mman.h>
  97 #include <sys/stat.h>
  98
  99 #include "rtld.h"
 100
 101 /*
 102  * Pre-allocate mmap'ed pages
 103  */
 104 #define NPOOLPAGES      (32*1024/pagesz)
 105 static char             *pagepool_start, *pagepool_end;
 106 static int              morepages(int);
 107 #define PAGEPOOL_SIZE   (size_t)(pagepool_end - pagepool_start)
 108
 109 /*
 110  * The overhead on a block is at least 4 bytes.  When free, this space
 111  * contains a pointer to the next free block, and the bottom two bits must
 112  * be zero.  When in use, the first byte is set to MAGIC, and the second
 113  * byte is the size index.  The remaining bytes are for alignment.
 114  * If range checking is enabled then a second word holds the size of the
 115  * requested block, less 1, rounded up to a multiple of sizeof(RMAGIC).
 116  * The order of elements is critical: ov_magic must overlay the low order
 117  * bits of ov_next, and ov_magic can not be a valid ov_next bit pattern.
 118  */
 119 union   overhead {
 120         union   overhead *ov_next;      /* when free */
 121         struct {
 122                 u_char  ovu_magic;      /* magic number */
 123                 u_char  ovu_index;      /* bucket # */
 124 #ifdef RCHECK
 125                 u_short ovu_rmagic;     /* range magic number */
 126                 u_int   ovu_size;       /* actual block size */
 127 #endif
 128         } ovu;
 129 #define ov_magic        ovu.ovu_magic
 130 #define ov_index        ovu.ovu_index
 131 #define ov_rmagic       ovu.ovu_rmagic
 132 #define ov_size         ovu.ovu_size
 133 };
 134
 135 static void morecore(size_t);
 136 static void *imalloc(size_t);
 137
 138 #define MAGIC           0xef            /* magic # on accounting info */
 139 #define RMAGIC          0x5555          /* magic # on range info */
 140
 141 #ifdef RCHECK
 142 #define RSLOP           (sizeof (u_short))
 143 #else
 144 #define RSLOP           0
 145 #endif
 146
 147 /*
 148  * nextf[i] is the pointer to the next free block of size 2^(i+3).  The
 149  * smallest allocatable block is 8 bytes.  The overhead information
 150  * precedes the data area returned to the user.
 151  */
 152 #define NBUCKETS 30
 153 static  union overhead *nextf[NBUCKETS];
 154
 155 static  size_t pagesz;                  /* page size */
 156 static  size_t pagebucket;              /* page size bucket */
 157 static  size_t pageshift;               /* page size shift */
 158
 159 #ifdef MSTATS
 160 /*
 161  * nmalloc[i] is the difference between the number of mallocs and frees
 162  * for a given block size.
 163  */
 164 static  u_int nmalloc[NBUCKETS];
 165 #endif
 166
 167 #if defined(MALLOC_DEBUG) || defined(RCHECK)
 168 #define ASSERT(p)   if (!(p)) botch("p")
 169 static void
 170 botch(const char *s)
 171 {
 172     xwarnx("\r\nassertion botched: %s\r\n", s);
 173     abort();
 174 }
 175 #else
 176 #define ASSERT(p)
 177 #endif
 178
 179 #define TRACE() xprintf("TRACE %s:%d\n", __FILE__, __LINE__)
 180
 181 static void *
 182 imalloc(size_t nbytes)
 183 {
 184         union overhead *op;
 185         size_t bucket;
 186         size_t n, m;
 187         unsigned amt;
 188
 189         /*
 190          * First time malloc is called, setup page size and
 191          * align break pointer so all data will be page aligned.
 192          */
 193         if (pagesz == 0) {
 194                 pagesz = n = _rtld_pagesz;
 195                 if (morepages(NPOOLPAGES) == 0)
 196                         return NULL;
 197                 op = (union overhead *)(pagepool_start);
 198                 m = sizeof (*op) - (((char *)op - (char *)NULL) & (n - 1));
 199                 if (n < m)
 200                         n += pagesz - m;
 201                 else
 202                         n -= m;
 203                 if (n) {
 204                         pagepool_start += n;
 205                 }
 206                 bucket = 0;
 207                 amt = sizeof(union overhead);
 208                 while (pagesz > amt) {
 209                         amt <<= 1;
 210                         bucket++;
 211                 }
 212                 pagebucket = bucket;
 213                 pageshift = ffs(pagesz) - 1;
 214         }
 215         /*
 216          * Convert amount of memory requested into closest block size
 217          * stored in hash buckets which satisfies request.
 218          * Account for space used per block for accounting.
 219          */
 220         if (nbytes <= (n = pagesz - sizeof (*op) - RSLOP)) {
 221                 if (sizeof(union overhead) & (sizeof(union overhead) - 1)) {
 222                     amt = sizeof(union overhead) * 2;
 223                     bucket = 1;
 224                 } else {
 225                     amt = sizeof(union overhead); /* size of first bucket */
 226                     bucket = 0;
 227                 }
 228                 n = -(sizeof (*op) + RSLOP);
 229         } else {
 230                 amt = pagesz;
 231                 bucket = pagebucket;
 232         }
 233         while (nbytes > amt + n) {
 234                 amt <<= 1;
 235                 if (amt == 0)
 236                         return (NULL);
 237                 bucket++;
 238         }
 239         /*
 240          * If nothing in hash bucket right now,
 241          * request more memory from the system.
 242          */
 243         if ((op = nextf[bucket]) == NULL) {
 244                 morecore(bucket);
 245                 if ((op = nextf[bucket]) == NULL)
 246                         return (NULL);
 247         }
 248         /* remove from linked list */
 249         nextf[bucket] = op->ov_next;
 250         op->ov_magic = MAGIC;
 251         op->ov_index = bucket;
 252 #ifdef MSTATS
 253         nmalloc[bucket]++;
 254 #endif
 255 #ifdef RCHECK
 256         /*
 257          * Record allocated size of block and
 258          * bound space with magic numbers.
 259          */
 260         op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
 261         op->ov_rmagic = RMAGIC;
 262         *(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
 263 #endif
 264         return ((char *)(op + 1));
 265 }
 266
 267 /*
 268  * Allocate more memory to the indicated bucket.
 269  */
 270 static void
 271 morecore(size_t bucket)
 272 {
 273         union overhead *op;
 274         size_t sz;              /* size of desired block */
 275         size_t amt;             /* amount to allocate */
 276         size_t nblks;           /* how many blocks we get */
 277
 278         /*
 279          * sbrk_size <= 0 only for big, FLUFFY, requests (about
 280          * 2^30 bytes on a VAX, I think) or for a negative arg.
 281          */
 282         sz = 1 << (bucket + 3);
 283 #ifdef MALLOC_DEBUG
 284         ASSERT(sz > 0);
 285 #endif
 286         if (sz < pagesz) {
 287                 amt = pagesz;
 288                 nblks = amt >> (bucket + 3);
 289         } else {
 290                 amt = sz + pagesz;
 291                 nblks = 1;
 292         }
 293         if (amt > PAGEPOOL_SIZE)
 294                 if (morepages((amt >> pageshift) + NPOOLPAGES) == 0)
 295                         return;
 296         op = (union overhead *)pagepool_start;
 297         pagepool_start += amt;
 298
 299         /*
 300          * Add new memory allocated to that on
 301          * free list for this hash bucket.
 302          */
 303         nextf[bucket] = op;
 304         while (--nblks > 0) {
 305                 op->ov_next = (union overhead *)((caddr_t)op + sz);
 306                 op = (union overhead *)((caddr_t)op + sz);
 307         }
 308 }
 309
 310 void
 311 xfree(void *cp)
 312 {
 313         int size;
 314         union overhead *op;
 315
 316         if (cp == NULL)
 317                 return;
 318         op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
 319 #ifdef MALLOC_DEBUG
 320         ASSERT(op->ov_magic == MAGIC);          /* make sure it was in use */
 321 #else
 322         if (op->ov_magic != MAGIC)
 323                 return;                         /* sanity */
 324 #endif
 325 #ifdef RCHECK
 326         ASSERT(op->ov_rmagic == RMAGIC);
 327         ASSERT(*(u_short *)((caddr_t)(op + 1) + op->ov_size) == RMAGIC);
 328 #endif
 329         size = op->ov_index;
 330         ASSERT(size < NBUCKETS);
 331         op->ov_next = nextf[size];      /* also clobbers ov_magic */
 332         nextf[size] = op;
 333 #ifdef MSTATS
 334         nmalloc[size]--;
 335 #endif
 336 }
 337
 338 static void *
 339 irealloc(void *cp, size_t nbytes)
 340 {
 341         size_t onb;
 342         size_t i;
 343         union overhead *op;
 344         char *res;
 345
 346         if (cp == NULL)
 347                 return (imalloc(nbytes));
 348         op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
 349         if (op->ov_magic != MAGIC) {
 350                 static const char *err_str =
 351                     "memory corruption or double free in realloc\n";
 352                 extern char *__progname;
 353                 write(STDERR_FILENO, __progname, strlen(__progname));
 354                 write(STDERR_FILENO, err_str, strlen(err_str));
 355                 abort();
 356         }
 357
 358         i = op->ov_index;
 359         onb = 1 << (i + 3);
 360         if (onb < pagesz)
 361                 onb -= sizeof (*op) + RSLOP;
 362         else
 363                 onb += pagesz - sizeof (*op) - RSLOP;
 364         /* avoid the copy if same size block */
 365         if (i) {
 366                 i = 1 << (i + 2);
 367                 if (i < pagesz)
 368                         i -= sizeof (*op) + RSLOP;
 369                 else
 370                         i += pagesz - sizeof (*op) - RSLOP;
 371         }
 372         if (nbytes <= onb && nbytes > i) {
 373 #ifdef RCHECK
 374                 op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
 375                 *(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
 376 #endif
 377                 return(cp);
 378         } else
 379                 xfree(cp);
 380         if ((res = imalloc(nbytes)) == NULL)
 381                 return (NULL);
 382         if (cp != res)          /* common optimization if "compacting" */
 383                 memcpy(res, cp, (nbytes < onb) ? nbytes : onb);
 384         return (res);
 385 }
 386
 387 #ifdef MSTATS
 388 /*
 389  * mstats - print out statistics about malloc
 390  *
 391  * Prints two lines of numbers, one showing the length of the free list
 392  * for each size category, the second showing the number of mallocs -
 393  * frees for each size category.
 394  */
 395 void
 396 mstats(char *s)
 397 {
 398         int i, j;
 399         union overhead *p;
 400         int totfree = 0,
 401         totused = 0;
 402
 403         xprintf("Memory allocation statistics %s\nfree:\t", s);
 404         for (i = 0; i < NBUCKETS; i++) {
 405                 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
 406                         ;
 407                 xprintf(" %d", j);
 408                 totfree += j * (1 << (i + 3));
 409         }
 410         xprintf("\nused:\t");
 411         for (i = 0; i < NBUCKETS; i++) {
 412                 xprintf(" %d", nmalloc[i]);
 413                 totused += nmalloc[i] * (1 << (i + 3));
 414         }
 415         xprintf("\n\tTotal in use: %d, total free: %d\n",
 416             totused, totfree);
 417 }
 418 #endif
 419
 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 }