xref: /freebsd/contrib/tcsh/tc.alloc.c (revision f3c5273d315a64826d2149ac453ff8c4583ddbe8)
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
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
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
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
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
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
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
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
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
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
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
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
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
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