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 } 490