1 /* $Header: /p/tcsh/cvsroot/tcsh/tc.alloc.c,v 3.50 2011/12/30 20:55:24 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 #ifdef HAVE_MALLINFO 43 #include <malloc.h> 44 #endif 45 46 RCSID("$tcsh: tc.alloc.c,v 3.50 2011/12/30 20:55:24 christos Exp $") 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 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 #define ROUNDUP 7 135 136 /* 137 * nextf[i] is the pointer to the next free block of size 2^(i+3). The 138 * smallest allocatable block is 8 bytes. The overhead information 139 * precedes the data area returned to the user. 140 */ 141 #define NBUCKETS ((sizeof(long) << 3) - 3) 142 static union overhead *nextf[NBUCKETS] IZERO_STRUCT; 143 144 /* 145 * nmalloc[i] is the difference between the number of mallocs and frees 146 * for a given block size. 147 */ 148 static U_int nmalloc[NBUCKETS] IZERO_STRUCT; 149 150 #ifndef lint 151 static int findbucket (union overhead *, int); 152 static void morecore (int); 153 #endif 154 155 156 #ifdef DEBUG 157 # define CHECK(a, str, p) \ 158 if (a) { \ 159 xprintf(str, p); \ 160 xprintf(" (memtop = %p membot = %p)\n", memtop, membot); \ 161 abort(); \ 162 } 163 #else 164 # define CHECK(a, str, p) \ 165 if (a) { \ 166 xprintf(str, p); \ 167 xprintf(" (memtop = %p membot = %p)\n", memtop, membot); \ 168 return; \ 169 } 170 #endif 171 172 memalign_t 173 malloc(size_t nbytes) 174 { 175 #ifndef lint 176 union overhead *p; 177 int bucket = 0; 178 unsigned shiftr; 179 180 /* 181 * Convert amount of memory requested into closest block size stored in 182 * hash buckets which satisfies request. Account for space used per block 183 * for accounting. 184 */ 185 #ifdef SUNOS4 186 /* 187 * SunOS localtime() overwrites the 9th byte on an 8 byte malloc().... 188 * so we get one more... 189 * From Michael Schroeder: This is not true. It depends on the 190 * timezone string. In Europe it can overwrite the 13th byte on a 191 * 12 byte malloc. 192 * So we punt and we always allocate an extra byte. 193 */ 194 nbytes++; 195 #endif 196 197 nbytes = MEMALIGN(MEMALIGN(sizeof(union overhead)) + nbytes + RSLOP); 198 shiftr = (nbytes - 1) >> 2; 199 200 /* apart from this loop, this is O(1) */ 201 while ((shiftr >>= 1) != 0) 202 bucket++; 203 /* 204 * If nothing in hash bucket right now, request more memory from the 205 * system. 206 */ 207 if (nextf[bucket] == NULL) 208 morecore(bucket); 209 if ((p = nextf[bucket]) == NULL) { 210 child++; 211 #ifndef DEBUG 212 out_of_memory(); 213 #else 214 showall(NULL, NULL); 215 xprintf(CGETS(19, 1, "nbytes=%zu: Out of memory\n"), nbytes); 216 abort(); 217 #endif 218 /* fool lint */ 219 return ((memalign_t) 0); 220 } 221 /* remove from linked list */ 222 nextf[bucket] = nextf[bucket]->ov_next; 223 p->ov_magic = MAGIC; 224 p->ov_index = bucket; 225 nmalloc[bucket]++; 226 #ifdef RCHECK 227 /* 228 * Record allocated size of block and bound space with magic numbers. 229 */ 230 p->ov_size = (p->ov_index <= 13) ? nbytes - 1 : 0; 231 p->ov_rmagic = RMAGIC; 232 *((U_int *) (((caddr_t) p) + nbytes - RSLOP)) = RMAGIC; 233 #endif 234 return ((memalign_t) (((caddr_t) p) + MEMALIGN(sizeof(union overhead)))); 235 #else 236 if (nbytes) 237 return ((memalign_t) 0); 238 else 239 return ((memalign_t) 0); 240 #endif /* !lint */ 241 } 242 243 #ifndef lint 244 /* 245 * Allocate more memory to the indicated bucket. 246 */ 247 static void 248 morecore(int bucket) 249 { 250 union overhead *op; 251 int rnu; /* 2^rnu bytes will be requested */ 252 int nblks; /* become nblks blocks of the desired size */ 253 int siz; 254 255 if (nextf[bucket]) 256 return; 257 /* 258 * Insure memory is allocated on a page boundary. Should make getpageize 259 * call? 260 */ 261 op = (union overhead *) sbrk(0); 262 memtop = (char *) op; 263 if (membot == NULL) 264 membot = memtop; 265 if ((long) op & 0x3ff) { 266 memtop = sbrk((int) (1024 - ((long) op & 0x3ff))); 267 memtop += (long) (1024 - ((long) op & 0x3ff)); 268 } 269 270 /* take 2k unless the block is bigger than that */ 271 rnu = (bucket <= 8) ? 11 : bucket + 3; 272 nblks = 1 << (rnu - (bucket + 3)); /* how many blocks to get */ 273 memtop = sbrk(1 << rnu); /* PWP */ 274 op = (union overhead *) memtop; 275 /* no more room! */ 276 if ((long) op == -1) 277 return; 278 memtop += (long) (1 << rnu); 279 /* 280 * Round up to minimum allocation size boundary and deduct from block count 281 * to reflect. 282 */ 283 if (((U_long) op) & ROUNDUP) { 284 op = (union overhead *) (((U_long) op + (ROUNDUP + 1)) & ~ROUNDUP); 285 nblks--; 286 } 287 /* 288 * Add new memory allocated to that on free list for this hash bucket. 289 */ 290 nextf[bucket] = op; 291 siz = 1 << (bucket + 3); 292 while (--nblks > 0) { 293 op->ov_next = (union overhead *) (((caddr_t) op) + siz); 294 op = (union overhead *) (((caddr_t) op) + siz); 295 } 296 op->ov_next = NULL; 297 } 298 299 #endif 300 301 void 302 free(ptr_t cp) 303 { 304 #ifndef lint 305 int size; 306 union overhead *op; 307 308 /* 309 * the don't free flag is there so that we avoid os bugs in routines 310 * that free invalid pointers! 311 */ 312 if (cp == NULL || dont_free) 313 return; 314 CHECK(!memtop || !membot, 315 CGETS(19, 2, "free(%p) called before any allocations."), cp); 316 CHECK(cp > (ptr_t) memtop, 317 CGETS(19, 3, "free(%p) above top of memory."), cp); 318 CHECK(cp < (ptr_t) membot, 319 CGETS(19, 4, "free(%p) below bottom of memory."), cp); 320 op = (union overhead *) (((caddr_t) cp) - MEMALIGN(sizeof(union overhead))); 321 CHECK(op->ov_magic != MAGIC, 322 CGETS(19, 5, "free(%p) bad block."), cp); 323 324 #ifdef RCHECK 325 if (op->ov_index <= 13) 326 CHECK(*(U_int *) ((caddr_t) op + op->ov_size + 1 - RSLOP) != RMAGIC, 327 CGETS(19, 6, "free(%p) bad range check."), cp); 328 #endif 329 CHECK(op->ov_index >= NBUCKETS, 330 CGETS(19, 7, "free(%p) bad block index."), cp); 331 size = op->ov_index; 332 op->ov_next = nextf[size]; 333 nextf[size] = op; 334 335 nmalloc[size]--; 336 337 #else 338 if (cp == NULL) 339 return; 340 #endif 341 } 342 343 memalign_t 344 calloc(size_t i, size_t j) 345 { 346 #ifndef lint 347 char *cp; 348 349 i *= j; 350 cp = xmalloc(i); 351 memset(cp, 0, i); 352 353 return ((memalign_t) cp); 354 #else 355 if (i && j) 356 return ((memalign_t) 0); 357 else 358 return ((memalign_t) 0); 359 #endif 360 } 361 362 /* 363 * When a program attempts "storage compaction" as mentioned in the 364 * old malloc man page, it realloc's an already freed block. Usually 365 * this is the last block it freed; occasionally it might be farther 366 * back. We have to search all the free lists for the block in order 367 * to determine its bucket: 1st we make one pass thru the lists 368 * checking only the first block in each; if that fails we search 369 * ``realloc_srchlen'' blocks in each list for a match (the variable 370 * is extern so the caller can modify it). If that fails we just copy 371 * however many bytes was given to realloc() and hope it's not huge. 372 */ 373 #ifndef lint 374 /* 4 should be plenty, -1 =>'s whole list */ 375 static int realloc_srchlen = 4; 376 #endif /* lint */ 377 378 memalign_t 379 realloc(ptr_t cp, size_t nbytes) 380 { 381 #ifndef lint 382 U_int onb; 383 union overhead *op; 384 ptr_t res; 385 int i; 386 int was_alloced = 0; 387 388 if (cp == NULL) 389 return (malloc(nbytes)); 390 op = (union overhead *) (((caddr_t) cp) - MEMALIGN(sizeof(union overhead))); 391 if (op->ov_magic == MAGIC) { 392 was_alloced++; 393 i = op->ov_index; 394 } 395 else 396 /* 397 * Already free, doing "compaction". 398 * 399 * Search for the old block of memory on the free list. First, check the 400 * most common case (last element free'd), then (this failing) the last 401 * ``realloc_srchlen'' items free'd. If all lookups fail, then assume 402 * the size of the memory block being realloc'd is the smallest 403 * possible. 404 */ 405 if ((i = findbucket(op, 1)) < 0 && 406 (i = findbucket(op, realloc_srchlen)) < 0) 407 i = 0; 408 409 onb = MEMALIGN(nbytes + MEMALIGN(sizeof(union overhead)) + RSLOP); 410 411 /* avoid the copy if same size block */ 412 if (was_alloced && (onb <= (U_int) (1 << (i + 3))) && 413 (onb > (U_int) (1 << (i + 2)))) { 414 #ifdef RCHECK 415 /* JMR: formerly this wasn't updated ! */ 416 nbytes = MEMALIGN(MEMALIGN(sizeof(union overhead))+nbytes+RSLOP); 417 *((U_int *) (((caddr_t) op) + nbytes - RSLOP)) = RMAGIC; 418 op->ov_rmagic = RMAGIC; 419 op->ov_size = (op->ov_index <= 13) ? nbytes - 1 : 0; 420 #endif 421 return ((memalign_t) cp); 422 } 423 if ((res = malloc(nbytes)) == NULL) 424 return ((memalign_t) NULL); 425 if (cp != res) { /* common optimization */ 426 /* 427 * christos: this used to copy nbytes! It should copy the 428 * smaller of the old and new size 429 */ 430 onb = (1 << (i + 3)) - MEMALIGN(sizeof(union overhead)) - RSLOP; 431 (void) memmove(res, cp, onb < nbytes ? onb : nbytes); 432 } 433 if (was_alloced) 434 free(cp); 435 return ((memalign_t) res); 436 #else 437 if (cp && nbytes) 438 return ((memalign_t) 0); 439 else 440 return ((memalign_t) 0); 441 #endif /* !lint */ 442 } 443 444 /* 445 * On linux, _nss_nis_setnetgrent() calls this function to determine 446 * the usable size of the pointer passed, but this is not a portable 447 * API, so we cannot use our malloc replacement without providing one. 448 * Thanks a lot glibc! 449 */ 450 #ifdef __linux__ 451 #define M_U_S_CONST 452 #else 453 #define M_U_S_CONST 454 #endif 455 size_t malloc_usable_size(M_U_S_CONST void *); 456 size_t 457 malloc_usable_size(M_U_S_CONST void *ptr) 458 { 459 const union overhead *op = (const union overhead *) 460 (((const char *) ptr) - MEMALIGN(sizeof(*op))); 461 if (op->ov_magic == MAGIC) 462 return 1 << (op->ov_index + 2); 463 else 464 return 0; 465 } 466 467 468 #ifndef lint 469 /* 470 * Search ``srchlen'' elements of each free list for a block whose 471 * header starts at ``freep''. If srchlen is -1 search the whole list. 472 * Return bucket number, or -1 if not found. 473 */ 474 static int 475 findbucket(union overhead *freep, int srchlen) 476 { 477 union overhead *p; 478 size_t i; 479 int j; 480 481 for (i = 0; i < NBUCKETS; i++) { 482 j = 0; 483 for (p = nextf[i]; p && j != srchlen; p = p->ov_next) { 484 if (p == freep) 485 return (i); 486 j++; 487 } 488 } 489 return (-1); 490 } 491 492 #endif 493 494 495 #else /* SYSMALLOC */ 496 497 /** 498 ** ``Protected versions'' of malloc, realloc, calloc, and free 499 ** 500 ** On many systems: 501 ** 502 ** 1. malloc(0) is bad 503 ** 2. free(0) is bad 504 ** 3. realloc(0, n) is bad 505 ** 4. realloc(n, 0) is bad 506 ** 507 ** Also we call our error routine if we run out of memory. 508 **/ 509 memalign_t 510 smalloc(size_t n) 511 { 512 ptr_t ptr; 513 514 n = n ? n : 1; 515 516 #ifdef HAVE_SBRK 517 if (membot == NULL) 518 membot = sbrk(0); 519 #endif /* HAVE_SBRK */ 520 521 if ((ptr = malloc(n)) == NULL) 522 out_of_memory(); 523 #ifndef HAVE_SBRK 524 if (memtop < ((char *) ptr) + n) 525 memtop = ((char *) ptr) + n; 526 if (membot == NULL) 527 membot = ptr; 528 #endif /* !HAVE_SBRK */ 529 return ((memalign_t) ptr); 530 } 531 532 memalign_t 533 srealloc(ptr_t p, size_t n) 534 { 535 ptr_t ptr; 536 537 n = n ? n : 1; 538 539 #ifdef HAVE_SBRK 540 if (membot == NULL) 541 membot = sbrk(0); 542 #endif /* HAVE_SBRK */ 543 544 if ((ptr = (p ? realloc(p, n) : malloc(n))) == NULL) 545 out_of_memory(); 546 #ifndef HAVE_SBRK 547 if (memtop < ((char *) ptr) + n) 548 memtop = ((char *) ptr) + n; 549 if (membot == NULL) 550 membot = ptr; 551 #endif /* !HAVE_SBRK */ 552 return ((memalign_t) ptr); 553 } 554 555 memalign_t 556 scalloc(size_t s, size_t n) 557 { 558 ptr_t ptr; 559 560 n *= s; 561 n = n ? n : 1; 562 563 #ifdef HAVE_SBRK 564 if (membot == NULL) 565 membot = sbrk(0); 566 #endif /* HAVE_SBRK */ 567 568 if ((ptr = malloc(n)) == NULL) 569 out_of_memory(); 570 571 memset (ptr, 0, n); 572 573 #ifndef HAVE_SBRK 574 if (memtop < ((char *) ptr) + n) 575 memtop = ((char *) ptr) + n; 576 if (membot == NULL) 577 membot = ptr; 578 #endif /* !HAVE_SBRK */ 579 580 return ((memalign_t) ptr); 581 } 582 583 void 584 sfree(ptr_t p) 585 { 586 if (p && !dont_free) 587 free(p); 588 } 589 590 #endif /* SYSMALLOC */ 591 592 /* 593 * mstats - print out statistics about malloc 594 * 595 * Prints two lines of numbers, one showing the length of the free list 596 * for each size category, the second showing the number of mallocs - 597 * frees for each size category. 598 */ 599 /*ARGSUSED*/ 600 void 601 showall(Char **v, struct command *c) 602 { 603 #ifndef SYSMALLOC 604 size_t i, j; 605 union overhead *p; 606 int totfree = 0, totused = 0; 607 608 xprintf(CGETS(19, 8, "%s current memory allocation:\nfree:\t"), progname); 609 for (i = 0; i < NBUCKETS; i++) { 610 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++) 611 continue; 612 xprintf(" %4zd", j); 613 totfree += j * (1 << (i + 3)); 614 } 615 xprintf("\n%s:\t", CGETS(19, 9, "used")); 616 for (i = 0; i < NBUCKETS; i++) { 617 xprintf(" %4d", nmalloc[i]); 618 totused += nmalloc[i] * (1 << (i + 3)); 619 } 620 xprintf(CGETS(19, 10, "\n\tTotal in use: %d, total free: %d\n"), 621 totused, totfree); 622 xprintf(CGETS(19, 11, 623 "\tAllocated memory from 0x%lx to 0x%lx. Real top at 0x%lx\n"), 624 (unsigned long) membot, (unsigned long) memtop, 625 (unsigned long) sbrk(0)); 626 #else /* SYSMALLOC */ 627 #ifndef HAVE_MALLINFO 628 #ifdef HAVE_SBRK 629 memtop = sbrk(0); 630 #endif /* HAVE_SBRK */ 631 xprintf(CGETS(19, 12, "Allocated memory from 0x%lx to 0x%lx (%ld).\n"), 632 (unsigned long) membot, (unsigned long) memtop, 633 (unsigned long) (memtop - membot)); 634 #else /* HAVE_MALLINFO */ 635 struct mallinfo mi; 636 637 mi = mallinfo(); 638 xprintf(CGETS(19, 13, "%s current memory allocation:\n"), progname); 639 xprintf(CGETS(19, 14, "Total space allocated from system: %d\n"), mi.arena); 640 xprintf(CGETS(19, 15, "Number of non-inuse chunks: %d\n"), mi.ordblks); 641 xprintf(CGETS(19, 16, "Number of mmapped regions: %d\n"), mi.hblks); 642 xprintf(CGETS(19, 17, "Total space in mmapped regions: %d\n"), mi.hblkhd); 643 xprintf(CGETS(19, 18, "Total allocated space: %d\n"), mi.uordblks); 644 xprintf(CGETS(19, 19, "Total non-inuse space: %d\n"), mi.fordblks); 645 xprintf(CGETS(19, 20, "Top-most, releasable space: %d\n"), mi.keepcost); 646 #endif /* HAVE_MALLINFO */ 647 #endif /* SYSMALLOC */ 648 USE(c); 649 USE(v); 650 } 651