1 /* $Header: /p/tcsh/cvsroot/tcsh/tc.alloc.c,v 3.56 2016/03/08 12:47:43 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 #if defined(HAVE_SBRK) && !defined(__APPLE__)
46 #define USE_SBRK
47 #endif
48
49 RCSID("$tcsh: tc.alloc.c,v 3.56 2016/03/08 12:47:43 christos Exp $")
50
51 #define RCHECK
52 #define DEBUG
53
54 static char *memtop = NULL; /* PWP: top of current memory */
55 static char *membot = NULL; /* PWP: bottom of allocatable memory */
56
57 int dont_free = 0;
58
59 #ifdef WINNT_NATIVE
60 # define malloc fmalloc
61 # define free ffree
62 # define calloc fcalloc
63 # define realloc frealloc
64 #endif /* WINNT_NATIVE */
65
66 #if !defined(DEBUG) || defined(SYSMALLOC)
67 static void
out_of_memory(void)68 out_of_memory (void)
69 {
70 static const char msg[] = "Out of memory\n";
71
72 TCSH_IGNORE(write(didfds ? 2 : SHDIAG, msg, strlen(msg)));
73 _exit(1);
74 }
75 #endif
76
77 #ifndef SYSMALLOC
78
79 #ifdef SX
80 extern void* sbrk();
81 #endif
82 /*
83 * Lots of os routines are busted and try to free invalid pointers.
84 * Although our free routine is smart enough and it will pick bad
85 * pointers most of the time, in cases where we know we are going to get
86 * a bad pointer, we'd rather leak.
87 */
88
89 #ifndef NULL
90 #define NULL 0
91 #endif
92
93 typedef unsigned char U_char; /* we don't really have signed chars */
94 typedef unsigned int U_int;
95 typedef unsigned short U_short;
96 typedef unsigned long U_long;
97
98
99 /*
100 * The overhead on a block is at least 4 bytes. When free, this space
101 * contains a pointer to the next free block, and the bottom two bits must
102 * be zero. When in use, the first byte is set to MAGIC, and the second
103 * byte is the size index. The remaining bytes are for alignment.
104 * If range checking is enabled and the size of the block fits
105 * in two bytes, then the top two bytes hold the size of the requested block
106 * plus the range checking words, and the header word MINUS ONE.
107 */
108
109
110 #define MEMALIGN(a) (((a) + ROUNDUP) & ~ROUNDUP)
111
112 union overhead {
113 union overhead *ov_next; /* when free */
114 struct {
115 U_char ovu_magic; /* magic number */
116 U_char ovu_index; /* bucket # */
117 #ifdef RCHECK
118 U_short ovu_size; /* actual block size */
119 U_int ovu_rmagic; /* range magic number */
120 #endif
121 } ovu;
122 #define ov_magic ovu.ovu_magic
123 #define ov_index ovu.ovu_index
124 #define ov_size ovu.ovu_size
125 #define ov_rmagic ovu.ovu_rmagic
126 };
127
128 #define MAGIC 0xfd /* magic # on accounting info */
129 #define RMAGIC 0x55555555 /* magic # on range info */
130 #ifdef RCHECK
131 #define RSLOP sizeof (U_int)
132 #else
133 #define RSLOP 0
134 #endif
135
136
137 #ifdef _LP64
138 #define ROUNDUP 15
139 #else
140 #define ROUNDUP 7
141 #endif
142
143 /*
144 * nextf[i] is the pointer to the next free block of size 2^(i+3). The
145 * smallest allocatable block is 8 bytes. The overhead information
146 * precedes the data area returned to the user.
147 */
148 #define NBUCKETS ((sizeof(long) << 3) - 3)
149 static union overhead *nextf[NBUCKETS] IZERO_STRUCT;
150
151 /*
152 * nmalloc[i] is the difference between the number of mallocs and frees
153 * for a given block size.
154 */
155 static U_int nmalloc[NBUCKETS] IZERO_STRUCT;
156
157 #ifndef lint
158 static int findbucket (union overhead *, int);
159 static void morecore (int);
160 #endif
161
162
163 #ifdef DEBUG
164 # define CHECK(a, str, p) \
165 if (a) { \
166 xprintf(str, p); \
167 xprintf(" (memtop = %p membot = %p)\n", memtop, membot); \
168 abort(); \
169 }
170 #else
171 # define CHECK(a, str, p) \
172 if (a) { \
173 xprintf(str, p); \
174 xprintf(" (memtop = %p membot = %p)\n", memtop, membot); \
175 return; \
176 }
177 #endif
178
179 memalign_t
malloc(size_t nbytes)180 malloc(size_t nbytes)
181 {
182 #ifndef lint
183 union overhead *p;
184 int bucket = 0;
185 unsigned shiftr;
186
187 /*
188 * Convert amount of memory requested into closest block size stored in
189 * hash buckets which satisfies request. Account for space used per block
190 * for accounting.
191 */
192 #ifdef SUNOS4
193 /*
194 * SunOS localtime() overwrites the 9th byte on an 8 byte malloc()....
195 * so we get one more...
196 * From Michael Schroeder: This is not true. It depends on the
197 * timezone string. In Europe it can overwrite the 13th byte on a
198 * 12 byte malloc.
199 * So we punt and we always allocate an extra byte.
200 */
201 nbytes++;
202 #endif
203
204 nbytes = MEMALIGN(MEMALIGN(sizeof(union overhead)) + nbytes + RSLOP);
205 shiftr = (nbytes - 1) >> 2;
206
207 /* apart from this loop, this is O(1) */
208 while ((shiftr >>= 1) != 0)
209 bucket++;
210 /*
211 * If nothing in hash bucket right now, request more memory from the
212 * system.
213 */
214 if (nextf[bucket] == NULL)
215 morecore(bucket);
216 if ((p = nextf[bucket]) == NULL) {
217 child++;
218 #ifndef DEBUG
219 out_of_memory();
220 #else
221 showall(NULL, NULL);
222 xprintf(CGETS(19, 1, "nbytes=%zu: Out of memory\n"), nbytes);
223 abort();
224 #endif
225 /* fool lint */
226 return ((memalign_t) 0);
227 }
228 /* remove from linked list */
229 nextf[bucket] = nextf[bucket]->ov_next;
230 p->ov_magic = MAGIC;
231 p->ov_index = bucket;
232 nmalloc[bucket]++;
233 #ifdef RCHECK
234 /*
235 * Record allocated size of block and bound space with magic numbers.
236 */
237 p->ov_size = (p->ov_index <= 13) ? nbytes - 1 : 0;
238 p->ov_rmagic = RMAGIC;
239 *((U_int *) (((caddr_t) p) + nbytes - RSLOP)) = RMAGIC;
240 #endif
241 return ((memalign_t) (((caddr_t) p) + MEMALIGN(sizeof(union overhead))));
242 #else
243 if (nbytes)
244 return ((memalign_t) 0);
245 else
246 return ((memalign_t) 0);
247 #endif /* !lint */
248 }
249
250 #ifndef lint
251 /*
252 * Allocate more memory to the indicated bucket.
253 */
254 static void
morecore(int bucket)255 morecore(int bucket)
256 {
257 union overhead *op;
258 int rnu; /* 2^rnu bytes will be requested */
259 int nblks; /* become nblks blocks of the desired size */
260 int siz;
261
262 if (nextf[bucket])
263 return;
264 /*
265 * Insure memory is allocated on a page boundary. Should make getpageize
266 * call?
267 */
268 op = (union overhead *) sbrk(0);
269 memtop = (char *) op;
270 if (membot == NULL)
271 membot = memtop;
272 if ((long) op & 0x3ff) {
273 memtop = sbrk((int) (1024 - ((long) op & 0x3ff)));
274 memtop += (long) (1024 - ((long) op & 0x3ff));
275 }
276
277 /* take 2k unless the block is bigger than that */
278 rnu = (bucket <= 8) ? 11 : bucket + 3;
279 nblks = 1 << (rnu - (bucket + 3)); /* how many blocks to get */
280 memtop = sbrk(1 << rnu); /* PWP */
281 op = (union overhead *) memtop;
282 /* no more room! */
283 if ((long) op == -1)
284 return;
285 memtop += (long) (1 << rnu);
286 /*
287 * Round up to minimum allocation size boundary and deduct from block count
288 * to reflect.
289 */
290 if (((U_long) op) & ROUNDUP) {
291 op = (union overhead *) (((U_long) op + (ROUNDUP + 1)) & ~ROUNDUP);
292 nblks--;
293 }
294 /*
295 * Add new memory allocated to that on free list for this hash bucket.
296 */
297 nextf[bucket] = op;
298 siz = 1 << (bucket + 3);
299 while (--nblks > 0) {
300 op->ov_next = (union overhead *) (((caddr_t) op) + siz);
301 op = (union overhead *) (((caddr_t) op) + siz);
302 }
303 op->ov_next = NULL;
304 }
305
306 #endif
307
308 void
free(ptr_t cp)309 free(ptr_t cp)
310 {
311 #ifndef lint
312 int size;
313 union overhead *op;
314
315 /*
316 * the don't free flag is there so that we avoid os bugs in routines
317 * that free invalid pointers!
318 */
319 if (cp == NULL || dont_free)
320 return;
321 CHECK(!memtop || !membot,
322 CGETS(19, 2, "free(%p) called before any allocations."), cp);
323 CHECK(cp > (ptr_t) memtop,
324 CGETS(19, 3, "free(%p) above top of memory."), cp);
325 CHECK(cp < (ptr_t) membot,
326 CGETS(19, 4, "free(%p) below bottom of memory."), cp);
327 op = (union overhead *) (((caddr_t) cp) - MEMALIGN(sizeof(union overhead)));
328 CHECK(op->ov_magic != MAGIC,
329 CGETS(19, 5, "free(%p) bad block."), cp);
330
331 #ifdef RCHECK
332 if (op->ov_index <= 13)
333 CHECK(*(U_int *) ((caddr_t) op + op->ov_size + 1 - RSLOP) != RMAGIC,
334 CGETS(19, 6, "free(%p) bad range check."), cp);
335 #endif
336 CHECK(op->ov_index >= NBUCKETS,
337 CGETS(19, 7, "free(%p) bad block index."), cp);
338 size = op->ov_index;
339 op->ov_next = nextf[size];
340 nextf[size] = op;
341
342 nmalloc[size]--;
343
344 #else
345 if (cp == NULL)
346 return;
347 #endif
348 }
349
350 memalign_t
calloc(size_t i,size_t j)351 calloc(size_t i, size_t j)
352 {
353 #ifndef lint
354 char *cp;
355 volatile size_t k;
356
357 i *= j;
358 cp = xmalloc(i);
359 /* Stop gcc 5.x from optimizing malloc+memset = calloc */
360 k = i;
361 memset(cp, 0, k);
362
363 return ((memalign_t) cp);
364 #else
365 if (i && j)
366 return ((memalign_t) 0);
367 else
368 return ((memalign_t) 0);
369 #endif
370 }
371
372 /*
373 * When a program attempts "storage compaction" as mentioned in the
374 * old malloc man page, it realloc's an already freed block. Usually
375 * this is the last block it freed; occasionally it might be farther
376 * back. We have to search all the free lists for the block in order
377 * to determine its bucket: 1st we make one pass thru the lists
378 * checking only the first block in each; if that fails we search
379 * ``realloc_srchlen'' blocks in each list for a match (the variable
380 * is extern so the caller can modify it). If that fails we just copy
381 * however many bytes was given to realloc() and hope it's not huge.
382 */
383 #ifndef lint
384 /* 4 should be plenty, -1 =>'s whole list */
385 static int realloc_srchlen = 4;
386 #endif /* lint */
387
388 memalign_t
realloc(ptr_t cp,size_t nbytes)389 realloc(ptr_t cp, size_t nbytes)
390 {
391 #ifndef lint
392 U_int onb;
393 union overhead *op;
394 ptr_t res;
395 int i;
396 int was_alloced = 0;
397
398 if (cp == NULL)
399 return (malloc(nbytes));
400 op = (union overhead *) (((caddr_t) cp) - MEMALIGN(sizeof(union overhead)));
401 if (op->ov_magic == MAGIC) {
402 was_alloced++;
403 i = op->ov_index;
404 }
405 else
406 /*
407 * Already free, doing "compaction".
408 *
409 * Search for the old block of memory on the free list. First, check the
410 * most common case (last element free'd), then (this failing) the last
411 * ``realloc_srchlen'' items free'd. If all lookups fail, then assume
412 * the size of the memory block being realloc'd is the smallest
413 * possible.
414 */
415 if ((i = findbucket(op, 1)) < 0 &&
416 (i = findbucket(op, realloc_srchlen)) < 0)
417 i = 0;
418
419 onb = MEMALIGN(nbytes + MEMALIGN(sizeof(union overhead)) + RSLOP);
420
421 /* avoid the copy if same size block */
422 if (was_alloced && (onb <= (U_int) (1 << (i + 3))) &&
423 (onb > (U_int) (1 << (i + 2)))) {
424 #ifdef RCHECK
425 /* JMR: formerly this wasn't updated ! */
426 nbytes = MEMALIGN(MEMALIGN(sizeof(union overhead))+nbytes+RSLOP);
427 *((U_int *) (((caddr_t) op) + nbytes - RSLOP)) = RMAGIC;
428 op->ov_rmagic = RMAGIC;
429 op->ov_size = (op->ov_index <= 13) ? nbytes - 1 : 0;
430 #endif
431 return ((memalign_t) cp);
432 }
433 if ((res = malloc(nbytes)) == NULL)
434 return ((memalign_t) NULL);
435 if (cp != res) { /* common optimization */
436 /*
437 * christos: this used to copy nbytes! It should copy the
438 * smaller of the old and new size
439 */
440 onb = (1 << (i + 3)) - MEMALIGN(sizeof(union overhead)) - RSLOP;
441 (void) memmove(res, cp, onb < nbytes ? onb : nbytes);
442 }
443 if (was_alloced)
444 free(cp);
445 return ((memalign_t) res);
446 #else
447 if (cp && nbytes)
448 return ((memalign_t) 0);
449 else
450 return ((memalign_t) 0);
451 #endif /* !lint */
452 }
453
454 /*
455 * On linux, _nss_nis_setnetgrent() calls this function to determine
456 * the usable size of the pointer passed, but this is not a portable
457 * API, so we cannot use our malloc replacement without providing one.
458 * Thanks a lot glibc!
459 */
460 #ifdef __linux__
461 #define M_U_S_CONST
462 #else
463 #define M_U_S_CONST
464 #endif
465 size_t malloc_usable_size(M_U_S_CONST void *);
466 size_t
malloc_usable_size(M_U_S_CONST void * ptr)467 malloc_usable_size(M_U_S_CONST void *ptr)
468 {
469 const union overhead *op = (const union overhead *)
470 (((const char *) ptr) - MEMALIGN(sizeof(*op)));
471 if (op->ov_magic == MAGIC)
472 return 1 << (op->ov_index + 3);
473 else
474 return 0;
475 }
476
477
478 #ifndef lint
479 /*
480 * Search ``srchlen'' elements of each free list for a block whose
481 * header starts at ``freep''. If srchlen is -1 search the whole list.
482 * Return bucket number, or -1 if not found.
483 */
484 static int
findbucket(union overhead * freep,int srchlen)485 findbucket(union overhead *freep, int srchlen)
486 {
487 union overhead *p;
488 size_t i;
489 int j;
490
491 for (i = 0; i < NBUCKETS; i++) {
492 j = 0;
493 for (p = nextf[i]; p && j != srchlen; p = p->ov_next) {
494 if (p == freep)
495 return (i);
496 j++;
497 }
498 }
499 return (-1);
500 }
501
502 #endif
503
504
505 #else /* SYSMALLOC */
506
507 /**
508 ** ``Protected versions'' of malloc, realloc, calloc, and free
509 **
510 ** On many systems:
511 **
512 ** 1. malloc(0) is bad
513 ** 2. free(0) is bad
514 ** 3. realloc(0, n) is bad
515 ** 4. realloc(n, 0) is bad
516 **
517 ** Also we call our error routine if we run out of memory.
518 **/
519 memalign_t
smalloc(size_t n)520 smalloc(size_t n)
521 {
522 ptr_t ptr;
523
524 n = n ? n : 1;
525
526 #ifdef USE_SBRK
527 if (membot == NULL)
528 membot = sbrk(0);
529 #endif /* USE_SBRK */
530
531 if ((ptr = malloc(n)) == NULL)
532 out_of_memory();
533 #ifndef USE_SBRK
534 if (memtop < ((char *) ptr) + n)
535 memtop = ((char *) ptr) + n;
536 if (membot == NULL)
537 membot = ptr;
538 #endif /* !USE_SBRK */
539 return ((memalign_t) ptr);
540 }
541
542 memalign_t
srealloc(ptr_t p,size_t n)543 srealloc(ptr_t p, size_t n)
544 {
545 ptr_t ptr;
546
547 n = n ? n : 1;
548
549 #ifdef USE_SBRK
550 if (membot == NULL)
551 membot = sbrk(0);
552 #endif /* USE_SBRK */
553
554 if ((ptr = (p ? realloc(p, n) : malloc(n))) == NULL)
555 out_of_memory();
556 #ifndef USE_SBRK
557 if (memtop < ((char *) ptr) + n)
558 memtop = ((char *) ptr) + n;
559 if (membot == NULL)
560 membot = ptr;
561 #endif /* !USE_SBRK */
562 return ((memalign_t) ptr);
563 }
564
565 memalign_t
scalloc(size_t s,size_t n)566 scalloc(size_t s, size_t n)
567 {
568 ptr_t ptr;
569
570 n *= s;
571 n = n ? n : 1;
572
573 #ifdef USE_SBRK
574 if (membot == NULL)
575 membot = sbrk(0);
576 #endif /* USE_SBRK */
577
578 if ((ptr = malloc(n)) == NULL)
579 out_of_memory();
580
581 memset (ptr, 0, n);
582
583 #ifndef USE_SBRK
584 if (memtop < ((char *) ptr) + n)
585 memtop = ((char *) ptr) + n;
586 if (membot == NULL)
587 membot = ptr;
588 #endif /* !USE_SBRK */
589
590 return ((memalign_t) ptr);
591 }
592
593 void
sfree(ptr_t p)594 sfree(ptr_t p)
595 {
596 if (p && !dont_free)
597 free(p);
598 }
599
600 #endif /* SYSMALLOC */
601
602 /*
603 * mstats - print out statistics about malloc
604 *
605 * Prints two lines of numbers, one showing the length of the free list
606 * for each size category, the second showing the number of mallocs -
607 * frees for each size category.
608 */
609 /*ARGSUSED*/
610 void
showall(Char ** v,struct command * c)611 showall(Char **v, struct command *c)
612 {
613 #ifndef SYSMALLOC
614 size_t i, j;
615 union overhead *p;
616 int totfree = 0, totused = 0;
617
618 xprintf(CGETS(19, 8, "%s current memory allocation:\nfree:\t"), progname);
619 for (i = 0; i < NBUCKETS; i++) {
620 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
621 continue;
622 xprintf(" %4zd", j);
623 totfree += j * (1 << (i + 3));
624 }
625 xprintf("\n%s:\t", CGETS(19, 9, "used"));
626 for (i = 0; i < NBUCKETS; i++) {
627 xprintf(" %4d", nmalloc[i]);
628 totused += nmalloc[i] * (1 << (i + 3));
629 }
630 xprintf(CGETS(19, 10, "\n\tTotal in use: %d, total free: %d\n"),
631 totused, totfree);
632 xprintf(CGETS(19, 11,
633 "\tAllocated memory from 0x%lx to 0x%lx. Real top at 0x%lx\n"),
634 (unsigned long) membot, (unsigned long) memtop,
635 (unsigned long) sbrk(0));
636 #else /* SYSMALLOC */
637 #ifndef HAVE_MALLINFO
638 #ifdef USE_SBRK
639 memtop = sbrk(0);
640 #endif /* USE_SBRK */
641 xprintf(CGETS(19, 12, "Allocated memory from 0x%lx to 0x%lx (%ld).\n"),
642 (unsigned long) membot, (unsigned long) memtop,
643 (unsigned long) (memtop - membot));
644 #else /* HAVE_MALLINFO */
645 struct mallinfo mi;
646
647 mi = mallinfo();
648 xprintf(CGETS(19, 13, "%s current memory allocation:\n"), progname);
649 xprintf(CGETS(19, 14, "Total space allocated from system: %d\n"), mi.arena);
650 xprintf(CGETS(19, 15, "Number of non-inuse chunks: %d\n"), mi.ordblks);
651 xprintf(CGETS(19, 16, "Number of mmapped regions: %d\n"), mi.hblks);
652 xprintf(CGETS(19, 17, "Total space in mmapped regions: %d\n"), mi.hblkhd);
653 xprintf(CGETS(19, 18, "Total allocated space: %d\n"), mi.uordblks);
654 xprintf(CGETS(19, 19, "Total non-inuse space: %d\n"), mi.fordblks);
655 xprintf(CGETS(19, 20, "Top-most, releasable space: %d\n"), mi.keepcost);
656 #endif /* HAVE_MALLINFO */
657 #endif /* SYSMALLOC */
658 USE(c);
659 USE(v);
660 }
661