1 /* $Header: /src/pub/tcsh/tc.alloc.c,v 3.39 2005/01/05 16:06:14 christos Exp $ */ 2 /* 3 * tc.alloc.c (Caltech) 2/21/82 4 * Chris Kingsley, kingsley@cit-20. 5 * 6 * This is a very fast storage allocator. It allocates blocks of a small 7 * number of different sizes, and keeps free lists of each size. Blocks that 8 * don't exactly fit are passed up to the next larger size. In this 9 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long. 10 * This is designed for use in a program that uses vast quantities of memory, 11 * but bombs when it runs out. 12 */ 13 /*- 14 * Copyright (c) 1980, 1991 The Regents of the University of California. 15 * All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 3. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 */ 41 #include "sh.h" 42 43 RCSID("$Id: tc.alloc.c,v 3.39 2005/01/05 16:06:14 christos Exp $") 44 45 static char *memtop = NULL; /* PWP: top of current memory */ 46 static char *membot = NULL; /* PWP: bottom of allocatable memory */ 47 48 int dont_free = 0; 49 50 #ifdef WINNT_NATIVE 51 # define malloc fmalloc 52 # define free ffree 53 # define calloc fcalloc 54 # define realloc frealloc 55 #endif /* WINNT_NATIVE */ 56 57 #ifndef SYSMALLOC 58 59 #undef RCHECK 60 #undef DEBUG 61 62 #ifdef SX 63 extern void* sbrk(); 64 #endif 65 /* 66 * Lots of os routines are busted and try to free invalid pointers. 67 * Although our free routine is smart enough and it will pick bad 68 * pointers most of the time, in cases where we know we are going to get 69 * a bad pointer, we'd rather leak. 70 */ 71 72 #ifndef NULL 73 #define NULL 0 74 #endif 75 76 typedef unsigned char U_char; /* we don't really have signed chars */ 77 typedef unsigned int U_int; 78 typedef unsigned short U_short; 79 typedef unsigned long U_long; 80 81 82 /* 83 * The overhead on a block is at least 4 bytes. When free, this space 84 * contains a pointer to the next free block, and the bottom two bits must 85 * be zero. When in use, the first byte is set to MAGIC, and the second 86 * byte is the size index. The remaining bytes are for alignment. 87 * If range checking is enabled and the size of the block fits 88 * in two bytes, then the top two bytes hold the size of the requested block 89 * plus the range checking words, and the header word MINUS ONE. 90 */ 91 92 93 #define MEMALIGN(a) (((a) + ROUNDUP) & ~ROUNDUP) 94 95 union overhead { 96 union overhead *ov_next; /* when free */ 97 struct { 98 U_char ovu_magic; /* magic number */ 99 U_char ovu_index; /* bucket # */ 100 #ifdef RCHECK 101 U_short ovu_size; /* actual block size */ 102 U_int ovu_rmagic; /* range magic number */ 103 #endif 104 } ovu; 105 #define ov_magic ovu.ovu_magic 106 #define ov_index ovu.ovu_index 107 #define ov_size ovu.ovu_size 108 #define ov_rmagic ovu.ovu_rmagic 109 }; 110 111 #define MAGIC 0xfd /* magic # on accounting info */ 112 #define RMAGIC 0x55555555 /* magic # on range info */ 113 #ifdef RCHECK 114 #define RSLOP sizeof (U_int) 115 #else 116 #define RSLOP 0 117 #endif 118 119 120 #define ROUNDUP 7 121 122 /* 123 * nextf[i] is the pointer to the next free block of size 2^(i+3). The 124 * smallest allocatable block is 8 bytes. The overhead information 125 * precedes the data area returned to the user. 126 */ 127 #define NBUCKETS ((sizeof(long) << 3) - 3) 128 static union overhead *nextf[NBUCKETS] IZERO_STRUCT; 129 130 /* 131 * nmalloc[i] is the difference between the number of mallocs and frees 132 * for a given block size. 133 */ 134 static U_int nmalloc[NBUCKETS] IZERO_STRUCT; 135 136 #ifndef lint 137 static int findbucket __P((union overhead *, int)); 138 static void morecore __P((int)); 139 #endif 140 141 142 #ifdef DEBUG 143 # define CHECK(a, str, p) \ 144 if (a) { \ 145 xprintf(str, p); \ 146 xprintf(" (memtop = %lx membot = %lx)\n", memtop, membot); \ 147 abort(); \ 148 } 149 #else 150 # define CHECK(a, str, p) \ 151 if (a) { \ 152 xprintf(str, p); \ 153 xprintf(" (memtop = %lx membot = %lx)\n", memtop, membot); \ 154 return; \ 155 } 156 #endif 157 158 memalign_t 159 malloc(nbytes) 160 size_t nbytes; 161 { 162 #ifndef lint 163 union overhead *p; 164 int bucket = 0; 165 unsigned shiftr; 166 167 /* 168 * Convert amount of memory requested into closest block size stored in 169 * hash buckets which satisfies request. Account for space used per block 170 * for accounting. 171 */ 172 #ifdef SUNOS4 173 /* 174 * SunOS localtime() overwrites the 9th byte on an 8 byte malloc().... 175 * so we get one more... 176 * From Michael Schroeder: This is not true. It depends on the 177 * timezone string. In Europe it can overwrite the 13th byte on a 178 * 12 byte malloc. 179 * So we punt and we always allocate an extra byte. 180 */ 181 nbytes++; 182 #endif 183 184 nbytes = MEMALIGN(MEMALIGN(sizeof(union overhead)) + nbytes + RSLOP); 185 shiftr = (nbytes - 1) >> 2; 186 187 /* apart from this loop, this is O(1) */ 188 while ((shiftr >>= 1) != 0) 189 bucket++; 190 /* 191 * If nothing in hash bucket right now, request more memory from the 192 * system. 193 */ 194 if (nextf[bucket] == NULL) 195 morecore(bucket); 196 if ((p = (union overhead *) nextf[bucket]) == NULL) { 197 child++; 198 #ifndef DEBUG 199 stderror(ERR_NOMEM); 200 #else 201 showall(NULL, NULL); 202 xprintf(CGETS(19, 1, "nbytes=%d: Out of memory\n"), nbytes); 203 abort(); 204 #endif 205 /* fool lint */ 206 return ((memalign_t) 0); 207 } 208 /* remove from linked list */ 209 nextf[bucket] = nextf[bucket]->ov_next; 210 p->ov_magic = MAGIC; 211 p->ov_index = bucket; 212 nmalloc[bucket]++; 213 #ifdef RCHECK 214 /* 215 * Record allocated size of block and bound space with magic numbers. 216 */ 217 p->ov_size = (p->ov_index <= 13) ? nbytes - 1 : 0; 218 p->ov_rmagic = RMAGIC; 219 *((U_int *) (((caddr_t) p) + nbytes - RSLOP)) = RMAGIC; 220 #endif 221 return ((memalign_t) (((caddr_t) p) + MEMALIGN(sizeof(union overhead)))); 222 #else 223 if (nbytes) 224 return ((memalign_t) 0); 225 else 226 return ((memalign_t) 0); 227 #endif /* !lint */ 228 } 229 230 #ifndef lint 231 /* 232 * Allocate more memory to the indicated bucket. 233 */ 234 static void 235 morecore(bucket) 236 int bucket; 237 { 238 union overhead *op; 239 int rnu; /* 2^rnu bytes will be requested */ 240 int nblks; /* become nblks blocks of the desired size */ 241 int siz; 242 243 if (nextf[bucket]) 244 return; 245 /* 246 * Insure memory is allocated on a page boundary. Should make getpageize 247 * call? 248 */ 249 op = (union overhead *) sbrk(0); 250 memtop = (char *) op; 251 if (membot == NULL) 252 membot = memtop; 253 if ((long) op & 0x3ff) { 254 memtop = (char *) sbrk((int) (1024 - ((long) op & 0x3ff))); 255 memtop += (long) (1024 - ((long) op & 0x3ff)); 256 } 257 258 /* take 2k unless the block is bigger than that */ 259 rnu = (bucket <= 8) ? 11 : bucket + 3; 260 nblks = 1 << (rnu - (bucket + 3)); /* how many blocks to get */ 261 memtop = (char *) sbrk(1 << rnu); /* PWP */ 262 op = (union overhead *) memtop; 263 /* no more room! */ 264 if ((long) op == -1) 265 return; 266 memtop += (long) (1 << rnu); 267 /* 268 * Round up to minimum allocation size boundary and deduct from block count 269 * to reflect. 270 */ 271 if (((U_long) op) & ROUNDUP) { 272 op = (union overhead *) (((U_long) op + (ROUNDUP + 1)) & ~ROUNDUP); 273 nblks--; 274 } 275 /* 276 * Add new memory allocated to that on free list for this hash bucket. 277 */ 278 nextf[bucket] = op; 279 siz = 1 << (bucket + 3); 280 while (--nblks > 0) { 281 op->ov_next = (union overhead *) (((caddr_t) op) + siz); 282 op = (union overhead *) (((caddr_t) op) + siz); 283 } 284 op->ov_next = NULL; 285 } 286 287 #endif 288 289 void 290 free(cp) 291 ptr_t cp; 292 { 293 #ifndef lint 294 int size; 295 union overhead *op; 296 297 /* 298 * the don't free flag is there so that we avoid os bugs in routines 299 * that free invalid pointers! 300 */ 301 if (cp == NULL || dont_free) 302 return; 303 CHECK(!memtop || !membot, 304 CGETS(19, 2, "free(%lx) called before any allocations."), cp); 305 CHECK(cp > (ptr_t) memtop, 306 CGETS(19, 3, "free(%lx) above top of memory."), cp); 307 CHECK(cp < (ptr_t) membot, 308 CGETS(19, 4, "free(%lx) below bottom of memory."), cp); 309 op = (union overhead *) (((caddr_t) cp) - MEMALIGN(sizeof(union overhead))); 310 CHECK(op->ov_magic != MAGIC, 311 CGETS(19, 5, "free(%lx) bad block."), cp); 312 313 #ifdef RCHECK 314 if (op->ov_index <= 13) 315 CHECK(*(U_int *) ((caddr_t) op + op->ov_size + 1 - RSLOP) != RMAGIC, 316 CGETS(19, 6, "free(%lx) bad range check."), cp); 317 #endif 318 CHECK(op->ov_index >= NBUCKETS, 319 CGETS(19, 7, "free(%lx) bad block index."), cp); 320 size = op->ov_index; 321 op->ov_next = nextf[size]; 322 nextf[size] = op; 323 324 nmalloc[size]--; 325 326 #else 327 if (cp == NULL) 328 return; 329 #endif 330 } 331 332 memalign_t 333 calloc(i, j) 334 size_t i, j; 335 { 336 #ifndef lint 337 char *cp, *scp; 338 339 i *= j; 340 scp = cp = (char *) xmalloc((size_t) i); 341 if (i != 0) 342 do 343 *cp++ = 0; 344 while (--i); 345 346 return ((memalign_t) scp); 347 #else 348 if (i && j) 349 return ((memalign_t) 0); 350 else 351 return ((memalign_t) 0); 352 #endif 353 } 354 355 /* 356 * When a program attempts "storage compaction" as mentioned in the 357 * old malloc man page, it realloc's an already freed block. Usually 358 * this is the last block it freed; occasionally it might be farther 359 * back. We have to search all the free lists for the block in order 360 * to determine its bucket: 1st we make one pass thru the lists 361 * checking only the first block in each; if that fails we search 362 * ``realloc_srchlen'' blocks in each list for a match (the variable 363 * is extern so the caller can modify it). If that fails we just copy 364 * however many bytes was given to realloc() and hope it's not huge. 365 */ 366 #ifndef lint 367 /* 4 should be plenty, -1 =>'s whole list */ 368 static int realloc_srchlen = 4; 369 #endif /* lint */ 370 371 memalign_t 372 realloc(cp, nbytes) 373 ptr_t cp; 374 size_t nbytes; 375 { 376 #ifndef lint 377 U_int onb; 378 union overhead *op; 379 ptr_t res; 380 int i; 381 int was_alloced = 0; 382 383 if (cp == NULL) 384 return (malloc(nbytes)); 385 op = (union overhead *) (((caddr_t) cp) - MEMALIGN(sizeof(union overhead))); 386 if (op->ov_magic == MAGIC) { 387 was_alloced++; 388 i = op->ov_index; 389 } 390 else 391 /* 392 * Already free, doing "compaction". 393 * 394 * Search for the old block of memory on the free list. First, check the 395 * most common case (last element free'd), then (this failing) the last 396 * ``realloc_srchlen'' items free'd. If all lookups fail, then assume 397 * the size of the memory block being realloc'd is the smallest 398 * possible. 399 */ 400 if ((i = findbucket(op, 1)) < 0 && 401 (i = findbucket(op, realloc_srchlen)) < 0) 402 i = 0; 403 404 onb = MEMALIGN(nbytes + MEMALIGN(sizeof(union overhead)) + RSLOP); 405 406 /* avoid the copy if same size block */ 407 if (was_alloced && (onb <= (U_int) (1 << (i + 3))) && 408 (onb > (U_int) (1 << (i + 2)))) { 409 #ifdef RCHECK 410 /* JMR: formerly this wasn't updated ! */ 411 nbytes = MEMALIGN(MEMALIGN(sizeof(union overhead))+nbytes+RSLOP); 412 *((U_int *) (((caddr_t) op) + nbytes - RSLOP)) = RMAGIC; 413 op->ov_rmagic = RMAGIC; 414 op->ov_size = (op->ov_index <= 13) ? nbytes - 1 : 0; 415 #endif 416 return ((memalign_t) cp); 417 } 418 if ((res = malloc(nbytes)) == NULL) 419 return ((memalign_t) NULL); 420 if (cp != res) { /* common optimization */ 421 /* 422 * christos: this used to copy nbytes! It should copy the 423 * smaller of the old and new size 424 */ 425 onb = (1 << (i + 3)) - MEMALIGN(sizeof(union overhead)) - RSLOP; 426 (void) memmove((ptr_t) res, (ptr_t) cp, 427 (size_t) (onb < nbytes ? onb : nbytes)); 428 } 429 if (was_alloced) 430 free(cp); 431 return ((memalign_t) res); 432 #else 433 if (cp && nbytes) 434 return ((memalign_t) 0); 435 else 436 return ((memalign_t) 0); 437 #endif /* !lint */ 438 } 439 440 441 442 #ifndef lint 443 /* 444 * Search ``srchlen'' elements of each free list for a block whose 445 * header starts at ``freep''. If srchlen is -1 search the whole list. 446 * Return bucket number, or -1 if not found. 447 */ 448 static int 449 findbucket(freep, srchlen) 450 union overhead *freep; 451 int srchlen; 452 { 453 union overhead *p; 454 size_t i; 455 int j; 456 457 for (i = 0; i < NBUCKETS; i++) { 458 j = 0; 459 for (p = nextf[i]; p && j != srchlen; p = p->ov_next) { 460 if (p == freep) 461 return (i); 462 j++; 463 } 464 } 465 return (-1); 466 } 467 468 #endif 469 470 471 #else /* SYSMALLOC */ 472 473 /** 474 ** ``Protected versions'' of malloc, realloc, calloc, and free 475 ** 476 ** On many systems: 477 ** 478 ** 1. malloc(0) is bad 479 ** 2. free(0) is bad 480 ** 3. realloc(0, n) is bad 481 ** 4. realloc(n, 0) is bad 482 ** 483 ** Also we call our error routine if we run out of memory. 484 **/ 485 memalign_t 486 smalloc(n) 487 size_t n; 488 { 489 ptr_t ptr; 490 491 n = n ? n : 1; 492 493 #ifdef HAVE_SBRK 494 if (membot == NULL) 495 membot = (char*) sbrk(0); 496 #endif /* HAVE_SBRK */ 497 498 if ((ptr = malloc(n)) == (ptr_t) 0) { 499 child++; 500 stderror(ERR_NOMEM); 501 } 502 #ifndef HAVE_SBRK 503 if (memtop < ((char *) ptr) + n) 504 memtop = ((char *) ptr) + n; 505 if (membot == NULL) 506 membot = (char*) ptr; 507 #endif /* !HAVE_SBRK */ 508 return ((memalign_t) ptr); 509 } 510 511 memalign_t 512 srealloc(p, n) 513 ptr_t p; 514 size_t n; 515 { 516 ptr_t ptr; 517 518 n = n ? n : 1; 519 520 #ifdef HAVE_SBRK 521 if (membot == NULL) 522 membot = (char*) sbrk(0); 523 #endif /* HAVE_SBRK */ 524 525 if ((ptr = (p ? realloc(p, n) : malloc(n))) == (ptr_t) 0) { 526 child++; 527 stderror(ERR_NOMEM); 528 } 529 #ifndef HAVE_SBRK 530 if (memtop < ((char *) ptr) + n) 531 memtop = ((char *) ptr) + n; 532 if (membot == NULL) 533 membot = (char*) ptr; 534 #endif /* !HAVE_SBRK */ 535 return ((memalign_t) ptr); 536 } 537 538 memalign_t 539 scalloc(s, n) 540 size_t s, n; 541 { 542 char *sptr; 543 ptr_t ptr; 544 545 n *= s; 546 n = n ? n : 1; 547 548 #ifdef HAVE_SBRK 549 if (membot == NULL) 550 membot = (char*) sbrk(0); 551 #endif /* HAVE_SBRK */ 552 553 if ((ptr = malloc(n)) == (ptr_t) 0) { 554 child++; 555 stderror(ERR_NOMEM); 556 } 557 558 sptr = (char *) ptr; 559 if (n != 0) 560 do 561 *sptr++ = 0; 562 while (--n); 563 564 #ifndef HAVE_SBRK 565 if (memtop < ((char *) ptr) + n) 566 memtop = ((char *) ptr) + n; 567 if (membot == NULL) 568 membot = (char*) ptr; 569 #endif /* !HAVE_SBRK */ 570 571 return ((memalign_t) ptr); 572 } 573 574 void 575 sfree(p) 576 ptr_t p; 577 { 578 if (p && !dont_free) 579 free(p); 580 } 581 582 #endif /* SYSMALLOC */ 583 584 /* 585 * mstats - print out statistics about malloc 586 * 587 * Prints two lines of numbers, one showing the length of the free list 588 * for each size category, the second showing the number of mallocs - 589 * frees for each size category. 590 */ 591 /*ARGSUSED*/ 592 void 593 showall(v, c) 594 Char **v; 595 struct command *c; 596 { 597 #ifndef SYSMALLOC 598 size_t i, j; 599 union overhead *p; 600 int totfree = 0, totused = 0; 601 602 xprintf(CGETS(19, 8, "%s current memory allocation:\nfree:\t"), progname); 603 for (i = 0; i < NBUCKETS; i++) { 604 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++) 605 continue; 606 xprintf(" %4d", j); 607 totfree += j * (1 << (i + 3)); 608 } 609 xprintf(CGETS(19, 9, "\nused:\t")); 610 for (i = 0; i < NBUCKETS; i++) { 611 xprintf(" %4u", nmalloc[i]); 612 totused += nmalloc[i] * (1 << (i + 3)); 613 } 614 xprintf(CGETS(19, 10, "\n\tTotal in use: %d, total free: %d\n"), 615 totused, totfree); 616 xprintf(CGETS(19, 11, 617 "\tAllocated memory from 0x%lx to 0x%lx. Real top at 0x%lx\n"), 618 (unsigned long) membot, (unsigned long) memtop, 619 (unsigned long) sbrk(0)); 620 #else 621 #ifdef HAVE_SBRK 622 memtop = (char *) sbrk(0); 623 #endif /* HAVE_SBRK */ 624 xprintf(CGETS(19, 12, "Allocated memory from 0x%lx to 0x%lx (%ld).\n"), 625 (unsigned long) membot, (unsigned long) memtop, 626 (unsigned long) (memtop - membot)); 627 #endif /* SYSMALLOC */ 628 USE(c); 629 USE(v); 630 } 631