1 /* 2 * tc.alloc.c (Caltech) 2/21/82 3 * Chris Kingsley, kingsley@cit-20. 4 * 5 * This is a very fast storage allocator. It allocates blocks of a small 6 * number of different sizes, and keeps free lists of each size. Blocks that 7 * don't exactly fit are passed up to the next larger size. In this 8 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long. 9 * This is designed for use in a program that uses vast quantities of memory, 10 * but bombs when it runs out. 11 */ 12 /*- 13 * Copyright (c) 1980, 1991 The Regents of the University of California. 14 * All rights reserved. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 3. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 */ 40 #include "sh.h" 41 #ifdef HAVE_MALLINFO 42 #include <malloc.h> 43 #endif 44 #if defined(HAVE_SBRK) && !defined(__APPLE__) 45 #define USE_SBRK 46 #endif 47 48 #define RCHECK 49 #define DEBUG 50 51 static char *memtop = NULL; /* PWP: top of current memory */ 52 static char *membot = NULL; /* PWP: bottom of allocatable memory */ 53 54 int dont_free = 0; 55 56 #ifdef WINNT_NATIVE 57 # define malloc fmalloc 58 # define free ffree 59 # define calloc fcalloc 60 # define realloc frealloc 61 #endif /* WINNT_NATIVE */ 62 63 #if !defined(DEBUG) || defined(SYSMALLOC) 64 static void 65 out_of_memory (void) 66 { 67 static const char msg[] = "Out of memory\n"; 68 69 TCSH_IGNORE(write(didfds ? 2 : SHDIAG, msg, strlen(msg))); 70 _exit(1); 71 } 72 #endif 73 74 #ifndef SYSMALLOC 75 76 #ifdef SX 77 extern void* sbrk(); 78 #endif 79 /* 80 * Lots of os routines are busted and try to free invalid pointers. 81 * Although our free routine is smart enough and it will pick bad 82 * pointers most of the time, in cases where we know we are going to get 83 * a bad pointer, we'd rather leak. 84 */ 85 86 #ifndef NULL 87 #define NULL 0 88 #endif 89 90 typedef unsigned char U_char; /* we don't really have signed chars */ 91 typedef unsigned int U_int; 92 typedef unsigned short U_short; 93 typedef unsigned long U_long; 94 95 96 /* 97 * The overhead on a block is at least 4 bytes. When free, this space 98 * contains a pointer to the next free block, and the bottom two bits must 99 * be zero. When in use, the first byte is set to MAGIC, and the second 100 * byte is the size index. The remaining bytes are for alignment. 101 * If range checking is enabled and the size of the block fits 102 * in two bytes, then the top two bytes hold the size of the requested block 103 * plus the range checking words, and the header word MINUS ONE. 104 */ 105 106 107 #define MEMALIGN(a) (((a) + ROUNDUP) & ~ROUNDUP) 108 109 union overhead { 110 union overhead *ov_next; /* when free */ 111 struct { 112 U_char ovu_magic; /* magic number */ 113 U_char ovu_index; /* bucket # */ 114 #ifdef RCHECK 115 U_short ovu_size; /* actual block size */ 116 U_int ovu_rmagic; /* range magic number */ 117 #endif 118 } ovu; 119 #define ov_magic ovu.ovu_magic 120 #define ov_index ovu.ovu_index 121 #define ov_size ovu.ovu_size 122 #define ov_rmagic ovu.ovu_rmagic 123 }; 124 125 #define MAGIC 0xfd /* magic # on accounting info */ 126 #define RMAGIC 0x55555555 /* magic # on range info */ 127 #ifdef RCHECK 128 #define RSLOP sizeof (U_int) 129 #else 130 #define RSLOP 0 131 #endif 132 133 134 #ifdef _LP64 135 #define ROUNDUP 15 136 #else 137 #define ROUNDUP 7 138 #endif 139 140 /* 141 * nextf[i] is the pointer to the next free block of size 2^(i+3). The 142 * smallest allocatable block is 8 bytes. The overhead information 143 * precedes the data area returned to the user. 144 */ 145 #define NBUCKETS ((sizeof(long) << 3) - 3) 146 static union overhead *nextf[NBUCKETS] IZERO_STRUCT; 147 148 /* 149 * nmalloc[i] is the difference between the number of mallocs and frees 150 * for a given block size. 151 */ 152 static U_int nmalloc[NBUCKETS] IZERO_STRUCT; 153 154 #ifndef lint 155 static int findbucket (union overhead *, int); 156 static void morecore (int); 157 #endif 158 159 160 #ifdef DEBUG 161 # define CHECK(a, str, p) \ 162 if (a) { \ 163 xprintf(str, p); \ 164 xprintf(" (memtop = %p membot = %p)\n", memtop, membot); \ 165 abort(); \ 166 } 167 #else 168 # define CHECK(a, str, p) \ 169 if (a) { \ 170 xprintf(str, p); \ 171 xprintf(" (memtop = %p membot = %p)\n", memtop, membot); \ 172 return; \ 173 } 174 #endif 175 176 memalign_t 177 malloc(size_t nbytes) 178 { 179 #ifndef lint 180 union overhead *p; 181 int bucket = 0; 182 unsigned shiftr; 183 184 /* 185 * Convert amount of memory requested into closest block size stored in 186 * hash buckets which satisfies request. Account for space used per block 187 * for accounting. 188 */ 189 #ifdef SUNOS4 190 /* 191 * SunOS localtime() overwrites the 9th byte on an 8 byte malloc().... 192 * so we get one more... 193 * From Michael Schroeder: This is not true. It depends on the 194 * timezone string. In Europe it can overwrite the 13th byte on a 195 * 12 byte malloc. 196 * So we punt and we always allocate an extra byte. 197 */ 198 nbytes++; 199 #endif 200 201 nbytes = MEMALIGN(MEMALIGN(sizeof(union overhead)) + nbytes + RSLOP); 202 shiftr = (nbytes - 1) >> 2; 203 204 /* apart from this loop, this is O(1) */ 205 while ((shiftr >>= 1) != 0) 206 bucket++; 207 /* 208 * If nothing in hash bucket right now, request more memory from the 209 * system. 210 */ 211 if (nextf[bucket] == NULL) 212 morecore(bucket); 213 if ((p = nextf[bucket]) == NULL) { 214 child++; 215 #ifndef DEBUG 216 out_of_memory(); 217 #else 218 showall(NULL, NULL); 219 xprintf(CGETS(19, 1, "nbytes=%zu: Out of memory\n"), nbytes); 220 abort(); 221 #endif 222 /* fool lint */ 223 return ((memalign_t) 0); 224 } 225 /* remove from linked list */ 226 nextf[bucket] = nextf[bucket]->ov_next; 227 p->ov_magic = MAGIC; 228 p->ov_index = bucket; 229 nmalloc[bucket]++; 230 #ifdef RCHECK 231 /* 232 * Record allocated size of block and bound space with magic numbers. 233 */ 234 p->ov_size = (p->ov_index <= 13) ? (U_short)nbytes - 1 : 0; 235 p->ov_rmagic = RMAGIC; 236 *((U_int *) (((caddr_t) p) + nbytes - RSLOP)) = RMAGIC; 237 #endif 238 return ((memalign_t) (((caddr_t) p) + MEMALIGN(sizeof(union overhead)))); 239 #else 240 if (nbytes) 241 return ((memalign_t) 0); 242 else 243 return ((memalign_t) 0); 244 #endif /* !lint */ 245 } 246 247 #ifndef lint 248 /* 249 * Allocate more memory to the indicated bucket. 250 */ 251 static void 252 morecore(int bucket) 253 { 254 union overhead *op; 255 int rnu; /* 2^rnu bytes will be requested */ 256 int nblks; /* become nblks blocks of the desired size */ 257 int siz; 258 259 if (nextf[bucket]) 260 return; 261 /* 262 * Insure memory is allocated on a page boundary. Should make getpageize 263 * call? 264 */ 265 op = (union overhead *) sbrk(0); 266 memtop = (char *) op; 267 if (membot == NULL) 268 membot = memtop; 269 if ((long) op & 0x3ff) { 270 memtop = sbrk((int) (1024 - ((long) op & 0x3ff))); 271 memtop += (long) (1024 - ((long) op & 0x3ff)); 272 } 273 274 /* take 2k unless the block is bigger than that */ 275 rnu = (bucket <= 8) ? 11 : bucket + 3; 276 nblks = 1 << (rnu - (bucket + 3)); /* how many blocks to get */ 277 memtop = sbrk(1 << rnu); /* PWP */ 278 op = (union overhead *) memtop; 279 /* no more room! */ 280 if ((long) op == -1) 281 return; 282 memtop += (long) (1 << rnu); 283 /* 284 * Round up to minimum allocation size boundary and deduct from block count 285 * to reflect. 286 */ 287 if (((U_long) op) & ROUNDUP) { 288 op = (union overhead *) (((U_long) op + (ROUNDUP + 1)) & ~ROUNDUP); 289 nblks--; 290 } 291 /* 292 * Add new memory allocated to that on free list for this hash bucket. 293 */ 294 nextf[bucket] = op; 295 siz = 1 << (bucket + 3); 296 while (--nblks > 0) { 297 op->ov_next = (union overhead *) (((caddr_t) op) + siz); 298 op = (union overhead *) (((caddr_t) op) + siz); 299 } 300 op->ov_next = NULL; 301 } 302 303 #endif 304 305 void 306 free(ptr_t cp) 307 { 308 #ifndef lint 309 int size; 310 union overhead *op; 311 312 /* 313 * the don't free flag is there so that we avoid os bugs in routines 314 * that free invalid pointers! 315 */ 316 if (cp == NULL || dont_free) 317 return; 318 CHECK(!memtop || !membot, 319 CGETS(19, 2, "free(%p) called before any allocations."), cp); 320 CHECK(cp > (ptr_t) memtop, 321 CGETS(19, 3, "free(%p) above top of memory."), cp); 322 CHECK(cp < (ptr_t) membot, 323 CGETS(19, 4, "free(%p) below bottom of memory."), cp); 324 op = (union overhead *) (((caddr_t) cp) - MEMALIGN(sizeof(union overhead))); 325 CHECK(op->ov_magic != MAGIC, 326 CGETS(19, 5, "free(%p) bad block."), cp); 327 328 #ifdef RCHECK 329 if (op->ov_index <= 13) 330 CHECK(*(U_int *) ((caddr_t) op + op->ov_size + 1 - RSLOP) != RMAGIC, 331 CGETS(19, 6, "free(%p) bad range check."), cp); 332 #endif 333 CHECK(op->ov_index >= NBUCKETS, 334 CGETS(19, 7, "free(%p) bad block index."), cp); 335 size = op->ov_index; 336 op->ov_next = nextf[size]; 337 nextf[size] = op; 338 339 nmalloc[size]--; 340 341 #else 342 if (cp == NULL) 343 return; 344 #endif 345 } 346 347 memalign_t 348 calloc(size_t i, size_t j) 349 { 350 #ifndef lint 351 char *cp; 352 volatile size_t k; 353 354 i *= j; 355 cp = xmalloc(i); 356 /* Stop gcc 5.x from optimizing malloc+memset = calloc */ 357 k = i; 358 memset(cp, 0, k); 359 360 return ((memalign_t) cp); 361 #else 362 if (i && j) 363 return ((memalign_t) 0); 364 else 365 return ((memalign_t) 0); 366 #endif 367 } 368 369 /* 370 * When a program attempts "storage compaction" as mentioned in the 371 * old malloc man page, it realloc's an already freed block. Usually 372 * this is the last block it freed; occasionally it might be farther 373 * back. We have to search all the free lists for the block in order 374 * to determine its bucket: 1st we make one pass thru the lists 375 * checking only the first block in each; if that fails we search 376 * ``realloc_srchlen'' blocks in each list for a match (the variable 377 * is extern so the caller can modify it). If that fails we just copy 378 * however many bytes was given to realloc() and hope it's not huge. 379 */ 380 #ifndef lint 381 /* 4 should be plenty, -1 =>'s whole list */ 382 static int realloc_srchlen = 4; 383 #endif /* lint */ 384 385 memalign_t 386 realloc(ptr_t cp, size_t nbytes) 387 { 388 #ifndef lint 389 U_int onb; 390 union overhead *op; 391 ptr_t res; 392 int i; 393 int was_alloced = 0; 394 395 if (cp == NULL) 396 return (malloc(nbytes)); 397 op = (union overhead *) (((caddr_t) cp) - MEMALIGN(sizeof(union overhead))); 398 if (op->ov_magic == MAGIC) { 399 was_alloced++; 400 i = op->ov_index; 401 } 402 else 403 /* 404 * Already free, doing "compaction". 405 * 406 * Search for the old block of memory on the free list. First, check the 407 * most common case (last element free'd), then (this failing) the last 408 * ``realloc_srchlen'' items free'd. If all lookups fail, then assume 409 * the size of the memory block being realloc'd is the smallest 410 * possible. 411 */ 412 if ((i = findbucket(op, 1)) < 0 && 413 (i = findbucket(op, realloc_srchlen)) < 0) 414 i = 0; 415 416 onb = MEMALIGN(nbytes + MEMALIGN(sizeof(union overhead)) + RSLOP); 417 418 /* avoid the copy if same size block */ 419 if (was_alloced && (onb <= (U_int) (1 << (i + 3))) && 420 (onb > (U_int) (1 << (i + 2)))) { 421 #ifdef RCHECK 422 /* JMR: formerly this wasn't updated ! */ 423 nbytes = MEMALIGN(MEMALIGN(sizeof(union overhead))+nbytes+RSLOP); 424 *((U_int *) (((caddr_t) op) + nbytes - RSLOP)) = RMAGIC; 425 op->ov_rmagic = RMAGIC; 426 op->ov_size = (op->ov_index <= 13) ? (U_short)nbytes - 1 : 0; 427 #endif 428 return ((memalign_t) cp); 429 } 430 if ((res = malloc(nbytes)) == NULL) 431 return ((memalign_t) NULL); 432 if (cp != res) { /* common optimization */ 433 /* 434 * christos: this used to copy nbytes! It should copy the 435 * smaller of the old and new size 436 */ 437 onb = (1 << (i + 3)) - MEMALIGN(sizeof(union overhead)) - RSLOP; 438 (void) memmove(res, cp, onb < nbytes ? onb : nbytes); 439 } 440 if (was_alloced) 441 free(cp); 442 return ((memalign_t) res); 443 #else 444 if (cp && nbytes) 445 return ((memalign_t) 0); 446 else 447 return ((memalign_t) 0); 448 #endif /* !lint */ 449 } 450 451 /* 452 * On linux, _nss_nis_setnetgrent() calls this function to determine 453 * the usable size of the pointer passed, but this is not a portable 454 * API, so we cannot use our malloc replacement without providing one. 455 * Thanks a lot glibc! 456 */ 457 #ifdef __linux__ 458 #define M_U_S_CONST 459 #else 460 #define M_U_S_CONST 461 #endif 462 size_t malloc_usable_size(M_U_S_CONST void *); 463 size_t 464 malloc_usable_size(M_U_S_CONST void *ptr) 465 { 466 const union overhead *op = (const union overhead *) 467 (((const char *) ptr) - MEMALIGN(sizeof(*op))); 468 if (op->ov_magic == MAGIC) 469 return 1 << (op->ov_index + 3); 470 else 471 return 0; 472 } 473 474 475 #ifndef lint 476 /* 477 * Search ``srchlen'' elements of each free list for a block whose 478 * header starts at ``freep''. If srchlen is -1 search the whole list. 479 * Return bucket number, or -1 if not found. 480 */ 481 static int 482 findbucket(union overhead *freep, int srchlen) 483 { 484 union overhead *p; 485 size_t i; 486 int j; 487 488 for (i = 0; i < NBUCKETS; i++) { 489 j = 0; 490 for (p = nextf[i]; p && j != srchlen; p = p->ov_next) { 491 if (p == freep) 492 return (i); 493 j++; 494 } 495 } 496 return (-1); 497 } 498 499 #endif 500 501 502 #else /* SYSMALLOC */ 503 504 /** 505 ** ``Protected versions'' of malloc, realloc, calloc, and free 506 ** 507 ** On many systems: 508 ** 509 ** 1. malloc(0) is bad 510 ** 2. free(0) is bad 511 ** 3. realloc(0, n) is bad 512 ** 4. realloc(n, 0) is bad 513 ** 514 ** Also we call our error routine if we run out of memory. 515 **/ 516 memalign_t 517 smalloc(size_t n) 518 { 519 ptr_t ptr; 520 521 n = n ? n : 1; 522 523 #ifdef USE_SBRK 524 if (membot == NULL) 525 membot = sbrk(0); 526 #endif /* USE_SBRK */ 527 528 if ((ptr = malloc(n)) == NULL) 529 out_of_memory(); 530 #ifndef USE_SBRK 531 if (memtop < ((char *) ptr) + n) 532 memtop = ((char *) ptr) + n; 533 if (membot == NULL) 534 membot = ptr; 535 #endif /* !USE_SBRK */ 536 return ((memalign_t) ptr); 537 } 538 539 memalign_t 540 srealloc(ptr_t p, size_t n) 541 { 542 ptr_t ptr; 543 544 n = n ? n : 1; 545 546 #ifdef USE_SBRK 547 if (membot == NULL) 548 membot = sbrk(0); 549 #endif /* USE_SBRK */ 550 551 if ((ptr = (p ? realloc(p, n) : malloc(n))) == NULL) 552 out_of_memory(); 553 #ifndef USE_SBRK 554 if (memtop < ((char *) ptr) + n) 555 memtop = ((char *) ptr) + n; 556 if (membot == NULL) 557 membot = ptr; 558 #endif /* !USE_SBRK */ 559 return ((memalign_t) ptr); 560 } 561 562 memalign_t 563 scalloc(size_t s, size_t n) 564 { 565 ptr_t ptr; 566 567 n *= s; 568 n = n ? n : 1; 569 570 #ifdef USE_SBRK 571 if (membot == NULL) 572 membot = sbrk(0); 573 #endif /* USE_SBRK */ 574 575 if ((ptr = malloc(n)) == NULL) 576 out_of_memory(); 577 578 memset (ptr, 0, n); 579 580 #ifndef USE_SBRK 581 if (memtop < ((char *) ptr) + n) 582 memtop = ((char *) ptr) + n; 583 if (membot == NULL) 584 membot = ptr; 585 #endif /* !USE_SBRK */ 586 587 return ((memalign_t) ptr); 588 } 589 590 void 591 sfree(ptr_t p) 592 { 593 if (p && !dont_free) 594 free(p); 595 } 596 597 #endif /* SYSMALLOC */ 598 599 /* 600 * mstats - print out statistics about malloc 601 * 602 * Prints two lines of numbers, one showing the length of the free list 603 * for each size category, the second showing the number of mallocs - 604 * frees for each size category. 605 */ 606 /*ARGSUSED*/ 607 void 608 showall(Char **v, struct command *c) 609 { 610 #ifndef SYSMALLOC 611 size_t i, j; 612 union overhead *p; 613 int totfree = 0, totused = 0; 614 615 xprintf(CGETS(19, 8, "%s current memory allocation:\nfree:\t"), progname); 616 for (i = 0; i < NBUCKETS; i++) { 617 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++) 618 continue; 619 xprintf(" %4zd", j); 620 totfree += j * (1 << (i + 3)); 621 } 622 xprintf("\n%s:\t", CGETS(19, 9, "used")); 623 for (i = 0; i < NBUCKETS; i++) { 624 xprintf(" %4d", nmalloc[i]); 625 totused += nmalloc[i] * (1 << (i + 3)); 626 } 627 xprintf(CGETS(19, 10, "\n\tTotal in use: %d, total free: %d\n"), 628 totused, totfree); 629 xprintf(CGETS(19, 11, 630 "\tAllocated memory from 0x%lx to 0x%lx. Real top at 0x%lx\n"), 631 (unsigned long) membot, (unsigned long) memtop, 632 (unsigned long) sbrk(0)); 633 #else /* SYSMALLOC */ 634 #ifndef HAVE_MALLINFO 635 #ifdef USE_SBRK 636 memtop = sbrk(0); 637 #endif /* USE_SBRK */ 638 xprintf(CGETS(19, 12, "Allocated memory from 0x%lx to 0x%lx (%ld).\n"), 639 (unsigned long) membot, (unsigned long) memtop, 640 (unsigned long) (memtop - membot)); 641 #else /* HAVE_MALLINFO */ 642 struct mallinfo mi; 643 644 mi = mallinfo(); 645 xprintf(CGETS(19, 13, "%s current memory allocation:\n"), progname); 646 xprintf(CGETS(19, 14, "Total space allocated from system: %d\n"), mi.arena); 647 xprintf(CGETS(19, 15, "Number of non-inuse chunks: %d\n"), mi.ordblks); 648 xprintf(CGETS(19, 16, "Number of mmapped regions: %d\n"), mi.hblks); 649 xprintf(CGETS(19, 17, "Total space in mmapped regions: %d\n"), mi.hblkhd); 650 xprintf(CGETS(19, 18, "Total allocated space: %d\n"), mi.uordblks); 651 xprintf(CGETS(19, 19, "Total non-inuse space: %d\n"), mi.fordblks); 652 xprintf(CGETS(19, 20, "Top-most, releasable space: %d\n"), mi.keepcost); 653 #endif /* HAVE_MALLINFO */ 654 #endif /* SYSMALLOC */ 655 USE(c); 656 USE(v); 657 } 658