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 #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 1.10 2010/12/03 23:07:49 joerg 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(const char *s) 164 { 165 xwarnx("\r\nassertion botched: %s\r\n", s); 166 abort(); 167 } 168 #else 169 #define ASSERT(p) 170 #endif 171 172 #define TRACE() xprintf("TRACE %s:%d\n", __FILE__, __LINE__) 173 174 static void * 175 imalloc(size_t nbytes) 176 { 177 union overhead *op; 178 size_t bucket; 179 size_t n, m; 180 unsigned amt; 181 182 /* 183 * First time malloc is called, setup page size and 184 * align break pointer so all data will be page aligned. 185 */ 186 if (pagesz == 0) { 187 pagesz = n = _rtld_pagesz; 188 if (morepages(NPOOLPAGES) == 0) 189 return NULL; 190 op = (union overhead *)(pagepool_start); 191 m = sizeof (*op) - (((char *)op - (char *)NULL) & (n - 1)); 192 if (n < m) 193 n += pagesz - m; 194 else 195 n -= m; 196 if (n) { 197 pagepool_start += n; 198 } 199 bucket = 0; 200 amt = sizeof(union overhead); 201 while (pagesz > amt) { 202 amt <<= 1; 203 bucket++; 204 } 205 pagebucket = bucket; 206 } 207 /* 208 * Convert amount of memory requested into closest block size 209 * stored in hash buckets which satisfies request. 210 * Account for space used per block for accounting. 211 */ 212 if (nbytes <= (n = pagesz - sizeof (*op) - RSLOP)) { 213 if (sizeof(union overhead) & (sizeof(union overhead) - 1)) { 214 amt = sizeof(union overhead) * 2; 215 bucket = 1; 216 } else { 217 amt = sizeof(union overhead); /* size of first bucket */ 218 bucket = 0; 219 } 220 n = -(sizeof (*op) + RSLOP); 221 } else { 222 amt = pagesz; 223 bucket = pagebucket; 224 } 225 while (nbytes > amt + n) { 226 amt <<= 1; 227 if (amt == 0) 228 return (NULL); 229 bucket++; 230 } 231 /* 232 * If nothing in hash bucket right now, 233 * request more memory from the system. 234 */ 235 if ((op = nextf[bucket]) == NULL) { 236 morecore(bucket); 237 if ((op = nextf[bucket]) == NULL) 238 return (NULL); 239 } 240 /* remove from linked list */ 241 nextf[bucket] = op->ov_next; 242 op->ov_magic = MAGIC; 243 op->ov_index = bucket; 244 #ifdef MSTATS 245 nmalloc[bucket]++; 246 #endif 247 #ifdef RCHECK 248 /* 249 * Record allocated size of block and 250 * bound space with magic numbers. 251 */ 252 op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1); 253 op->ov_rmagic = RMAGIC; 254 *(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC; 255 #endif 256 return ((char *)(op + 1)); 257 } 258 259 /* 260 * Allocate more memory to the indicated bucket. 261 */ 262 static void 263 morecore(size_t bucket) 264 { 265 union overhead *op; 266 size_t sz; /* size of desired block */ 267 size_t amt; /* amount to allocate */ 268 size_t nblks; /* how many blocks we get */ 269 270 /* 271 * sbrk_size <= 0 only for big, FLUFFY, requests (about 272 * 2^30 bytes on a VAX, I think) or for a negative arg. 273 */ 274 sz = 1 << (bucket + 3); 275 #ifdef MALLOC_DEBUG 276 ASSERT(sz > 0); 277 #endif 278 if (sz < pagesz) { 279 amt = pagesz; 280 nblks = amt / sz; 281 } else { 282 amt = sz + pagesz; 283 nblks = 1; 284 } 285 if (amt > PAGEPOOL_SIZE) 286 if (morepages(amt/pagesz + NPOOLPAGES) == 0) 287 return; 288 op = (union overhead *)pagepool_start; 289 pagepool_start += amt; 290 291 /* 292 * Add new memory allocated to that on 293 * free list for this hash bucket. 294 */ 295 nextf[bucket] = op; 296 while (--nblks > 0) { 297 op->ov_next = (union overhead *)((caddr_t)op + sz); 298 op = (union overhead *)((caddr_t)op + sz); 299 } 300 } 301 302 void 303 xfree(void *cp) 304 { 305 int size; 306 union overhead *op; 307 308 if (cp == NULL) 309 return; 310 op = (union overhead *)((caddr_t)cp - sizeof (union overhead)); 311 #ifdef MALLOC_DEBUG 312 ASSERT(op->ov_magic == MAGIC); /* make sure it was in use */ 313 #else 314 if (op->ov_magic != MAGIC) 315 return; /* sanity */ 316 #endif 317 #ifdef RCHECK 318 ASSERT(op->ov_rmagic == RMAGIC); 319 ASSERT(*(u_short *)((caddr_t)(op + 1) + op->ov_size) == RMAGIC); 320 #endif 321 size = op->ov_index; 322 ASSERT(size < NBUCKETS); 323 op->ov_next = nextf[size]; /* also clobbers ov_magic */ 324 nextf[size] = op; 325 #ifdef MSTATS 326 nmalloc[size]--; 327 #endif 328 } 329 330 static void * 331 irealloc(void *cp, size_t nbytes) 332 { 333 size_t onb; 334 size_t i; 335 union overhead *op; 336 char *res; 337 338 if (cp == NULL) 339 return (imalloc(nbytes)); 340 op = (union overhead *)((caddr_t)cp - sizeof (union overhead)); 341 if (op->ov_magic != MAGIC) { 342 static const char *err_str = 343 "memory corruption or double free in realloc\n"; 344 extern char *__progname; 345 write(STDERR_FILENO, __progname, strlen(__progname)); 346 write(STDERR_FILENO, err_str, strlen(err_str)); 347 abort(); 348 } 349 350 i = op->ov_index; 351 onb = 1 << (i + 3); 352 if (onb < pagesz) 353 onb -= sizeof (*op) + RSLOP; 354 else 355 onb += pagesz - sizeof (*op) - RSLOP; 356 /* avoid the copy if same size block */ 357 if (i) { 358 i = 1 << (i + 2); 359 if (i < pagesz) 360 i -= sizeof (*op) + RSLOP; 361 else 362 i += pagesz - sizeof (*op) - RSLOP; 363 } 364 if (nbytes <= onb && nbytes > i) { 365 #ifdef RCHECK 366 op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1); 367 *(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC; 368 #endif 369 return(cp); 370 } else 371 xfree(cp); 372 if ((res = imalloc(nbytes)) == NULL) 373 return (NULL); 374 if (cp != res) /* common optimization if "compacting" */ 375 memcpy(res, cp, (nbytes < onb) ? nbytes : onb); 376 return (res); 377 } 378 379 #ifdef MSTATS 380 /* 381 * mstats - print out statistics about malloc 382 * 383 * Prints two lines of numbers, one showing the length of the free list 384 * for each size category, the second showing the number of mallocs - 385 * frees for each size category. 386 */ 387 void 388 mstats(char *s) 389 { 390 int i, j; 391 union overhead *p; 392 int totfree = 0, 393 totused = 0; 394 395 xprintf("Memory allocation statistics %s\nfree:\t", s); 396 for (i = 0; i < NBUCKETS; i++) { 397 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++) 398 ; 399 xprintf(" %d", j); 400 totfree += j * (1 << (i + 3)); 401 } 402 xprintf("\nused:\t"); 403 for (i = 0; i < NBUCKETS; i++) { 404 xprintf(" %d", nmalloc[i]); 405 totused += nmalloc[i] * (1 << (i + 3)); 406 } 407 xprintf("\n\tTotal in use: %d, total free: %d\n", 408 totused, totfree); 409 } 410 #endif 411 412 413 static int 414 morepages(int n) 415 { 416 int fd = -1; 417 int offset; 418 419 #ifdef NEED_DEV_ZERO 420 fd = open("/dev/zero", O_RDWR, 0); 421 if (fd == -1) 422 xerr(1, "/dev/zero"); 423 #endif 424 425 if (PAGEPOOL_SIZE > pagesz) { 426 caddr_t addr = (caddr_t) 427 (((long)pagepool_start + pagesz - 1) & ~(pagesz - 1)); 428 if (munmap(addr, pagepool_end - addr) != 0) 429 xwarn("morepages: munmap %p", addr); 430 } 431 432 offset = (long)pagepool_start - ((long)pagepool_start & ~(pagesz - 1)); 433 434 if ((pagepool_start = mmap(0, n * pagesz, 435 PROT_READ|PROT_WRITE, 436 MAP_ANON|MAP_PRIVATE, fd, 0)) == (caddr_t)-1) { 437 xprintf("Cannot map anonymous memory"); 438 return 0; 439 } 440 pagepool_end = pagepool_start + n * pagesz; 441 pagepool_start += offset; 442 443 #ifdef NEED_DEV_ZERO 444 close(fd); 445 #endif 446 return n; 447 } 448 449 void * 450 xcalloc(size_t size) 451 { 452 453 return memset(xmalloc(size), 0, size); 454 } 455 456 void * 457 xmalloc(size_t size) 458 { 459 void *p = imalloc(size); 460 461 if (p == NULL) 462 xerr(1, "%s", xstrerror(errno)); 463 return p; 464 } 465 466 void * 467 xrealloc(void *p, size_t size) 468 { 469 p = irealloc(p, size); 470 471 if (p == NULL) 472 xerr(1, "%s", xstrerror(errno)); 473 return p; 474 } 475 476 char * 477 xstrdup(const char *str) 478 { 479 size_t len; 480 char *copy; 481 482 len = strlen(str) + 1; 483 copy = xmalloc(len); 484 memcpy(copy, str, len); 485 return (copy); 486 } 487