/* $Header: /p/tcsh/cvsroot/tcsh/tc.alloc.c,v 3.46 2006/03/02 18:46:44 christos Exp $ */
/*
* tc.alloc.c (Caltech) 2/21/82
* Chris Kingsley, kingsley@cit-20.
*
* This is a very fast storage allocator. It allocates blocks of a small
* number of different sizes, and keeps free lists of each size. Blocks that
* don't exactly fit are passed up to the next larger size. In this
* implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
* This is designed for use in a program that uses vast quantities of memory,
* but bombs when it runs out.
*/
/*-
* Copyright (c) 1980, 1991 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "sh.h"
RCSID("$tcsh: tc.alloc.c,v 3.46 2006/03/02 18:46:44 christos Exp $")
#define RCHECK
#define DEBUG
static char *memtop = NULL; /* PWP: top of current memory */
static char *membot = NULL; /* PWP: bottom of allocatable memory */
int dont_free = 0;
#ifdef WINNT_NATIVE
# define malloc fmalloc
# define free ffree
# define calloc fcalloc
# define realloc frealloc
#endif /* WINNT_NATIVE */
#if !defined(DEBUG) || defined(SYSMALLOC)
static void
out_of_memory (void)
{
static const char msg[] = "Out of memory\n";
write(didfds ? 2 : SHDIAG, msg, strlen(msg));
_exit(1);
}
#endif
#ifndef SYSMALLOC
#ifdef SX
extern void* sbrk();
#endif
/*
* Lots of os routines are busted and try to free invalid pointers.
* Although our free routine is smart enough and it will pick bad
* pointers most of the time, in cases where we know we are going to get
* a bad pointer, we'd rather leak.
*/
#ifndef NULL
#define NULL 0
#endif
typedef unsigned char U_char; /* we don't really have signed chars */
typedef unsigned int U_int;
typedef unsigned short U_short;
typedef unsigned long U_long;
/*
* The overhead on a block is at least 4 bytes. When free, this space
* contains a pointer to the next free block, and the bottom two bits must
* be zero. When in use, the first byte is set to MAGIC, and the second
* byte is the size index. The remaining bytes are for alignment.
* If range checking is enabled and the size of the block fits
* in two bytes, then the top two bytes hold the size of the requested block
* plus the range checking words, and the header word MINUS ONE.
*/
#define MEMALIGN(a) (((a) + ROUNDUP) & ~ROUNDUP)
union overhead {
union overhead *ov_next; /* when free */
struct {
U_char ovu_magic; /* magic number */
U_char ovu_index; /* bucket # */
#ifdef RCHECK
U_short ovu_size; /* actual block size */
U_int ovu_rmagic; /* range magic number */
#endif
} ovu;
#define ov_magic ovu.ovu_magic
#define ov_index ovu.ovu_index
#define ov_size ovu.ovu_size
#define ov_rmagic ovu.ovu_rmagic
};
#define MAGIC 0xfd /* magic # on accounting info */
#define RMAGIC 0x55555555 /* magic # on range info */
#ifdef RCHECK
#define RSLOP sizeof (U_int)
#else
#define RSLOP 0
#endif
#define ROUNDUP 7
/*
* nextf[i] is the pointer to the next free block of size 2^(i+3). The
* smallest allocatable block is 8 bytes. The overhead information
* precedes the data area returned to the user.
*/
#define NBUCKETS ((sizeof(long) << 3) - 3)
static union overhead *nextf[NBUCKETS] IZERO_STRUCT;
/*
* nmalloc[i] is the difference between the number of mallocs and frees
* for a given block size.
*/
static U_int nmalloc[NBUCKETS] IZERO_STRUCT;
#ifndef lint
static int findbucket (union overhead *, int);
static void morecore (int);
#endif
#ifdef DEBUG
# define CHECK(a, str, p) \
if (a) { \
xprintf(str, p); \
xprintf(" (memtop = %p membot = %p)\n", memtop, membot); \
abort(); \
}
#else
# define CHECK(a, str, p) \
if (a) { \
xprintf(str, p); \
xprintf(" (memtop = %p membot = %p)\n", memtop, membot); \
return; \
}
#endif
memalign_t
malloc(size_t nbytes)
{
#ifndef lint
union overhead *p;
int bucket = 0;
unsigned shiftr;
/*
* Convert amount of memory requested into closest block size stored in
* hash buckets which satisfies request. Account for space used per block
* for accounting.
*/
#ifdef SUNOS4
/*
* SunOS localtime() overwrites the 9th byte on an 8 byte malloc()....
* so we get one more...
* From Michael Schroeder: This is not true. It depends on the
* timezone string. In Europe it can overwrite the 13th byte on a
* 12 byte malloc.
* So we punt and we always allocate an extra byte.
*/
nbytes++;
#endif
nbytes = MEMALIGN(MEMALIGN(sizeof(union overhead)) + nbytes + RSLOP);
shiftr = (nbytes - 1) >> 2;
/* apart from this loop, this is O(1) */
while ((shiftr >>= 1) != 0)
bucket++;
/*
* If nothing in hash bucket right now, request more memory from the
* system.
*/
if (nextf[bucket] == NULL)
morecore(bucket);
if ((p = nextf[bucket]) == NULL) {
child++;
#ifndef DEBUG
out_of_memory();
#else
showall(NULL, NULL);
xprintf(CGETS(19, 1, "nbytes=%zu: Out of memory\n"), nbytes);
abort();
#endif
/* fool lint */
return ((memalign_t) 0);
}
/* remove from linked list */
nextf[bucket] = nextf[bucket]->ov_next;
p->ov_magic = MAGIC;
p->ov_index = bucket;
nmalloc[bucket]++;
#ifdef RCHECK
/*
* Record allocated size of block and bound space with magic numbers.
*/
p->ov_size = (p->ov_index <= 13) ? nbytes - 1 : 0;
p->ov_rmagic = RMAGIC;
*((U_int *) (((caddr_t) p) + nbytes - RSLOP)) = RMAGIC;
#endif
return ((memalign_t) (((caddr_t) p) + MEMALIGN(sizeof(union overhead))));
#else
if (nbytes)
return ((memalign_t) 0);
else
return ((memalign_t) 0);
#endif /* !lint */
}
#ifndef lint
/*
* Allocate more memory to the indicated bucket.
*/
static void
morecore(int bucket)
{
union overhead *op;
int rnu; /* 2^rnu bytes will be requested */
int nblks; /* become nblks blocks of the desired size */
int siz;
if (nextf[bucket])
return;
/*
* Insure memory is allocated on a page boundary. Should make getpageize
* call?
*/
op = (union overhead *) sbrk(0);
memtop = (char *) op;
if (membot == NULL)
membot = memtop;
if ((long) op & 0x3ff) {
memtop = sbrk((int) (1024 - ((long) op & 0x3ff)));
memtop += (long) (1024 - ((long) op & 0x3ff));
}
/* take 2k unless the block is bigger than that */
rnu = (bucket <= 8) ? 11 : bucket + 3;
nblks = 1 << (rnu - (bucket + 3)); /* how many blocks to get */
memtop = sbrk(1 << rnu); /* PWP */
op = (union overhead *) memtop;
/* no more room! */
if ((long) op == -1)
return;
memtop += (long) (1 << rnu);
/*
* Round up to minimum allocation size boundary and deduct from block count
* to reflect.
*/
if (((U_long) op) & ROUNDUP) {
op = (union overhead *) (((U_long) op + (ROUNDUP + 1)) & ~ROUNDUP);
nblks--;
}
/*
* Add new memory allocated to that on free list for this hash bucket.
*/
nextf[bucket] = op;
siz = 1 << (bucket + 3);
while (--nblks > 0) {
op->ov_next = (union overhead *) (((caddr_t) op) + siz);
op = (union overhead *) (((caddr_t) op) + siz);
}
op->ov_next = NULL;
}
#endif
void
free(ptr_t cp)
{
#ifndef lint
int size;
union overhead *op;
/*
* the don't free flag is there so that we avoid os bugs in routines
* that free invalid pointers!
*/
if (cp == NULL || dont_free)
return;
CHECK(!memtop || !membot,
CGETS(19, 2, "free(%p) called before any allocations."), cp);
CHECK(cp > (ptr_t) memtop,
CGETS(19, 3, "free(%p) above top of memory."), cp);
CHECK(cp < (ptr_t) membot,
CGETS(19, 4, "free(%p) below bottom of memory."), cp);
op = (union overhead *) (((caddr_t) cp) - MEMALIGN(sizeof(union overhead)));
CHECK(op->ov_magic != MAGIC,
CGETS(19, 5, "free(%p) bad block."), cp);
#ifdef RCHECK
if (op->ov_index <= 13)
CHECK(*(U_int *) ((caddr_t) op + op->ov_size + 1 - RSLOP) != RMAGIC,
CGETS(19, 6, "free(%p) bad range check."), cp);
#endif
CHECK(op->ov_index >= NBUCKETS,
CGETS(19, 7, "free(%p) bad block index."), cp);
size = op->ov_index;
op->ov_next = nextf[size];
nextf[size] = op;
nmalloc[size]--;
#else
if (cp == NULL)
return;
#endif
}
memalign_t
calloc(size_t i, size_t j)
{
#ifndef lint
char *cp;
i *= j;
cp = xmalloc(i);
memset(cp, 0, i);
return ((memalign_t) cp);
#else
if (i && j)
return ((memalign_t) 0);
else
return ((memalign_t) 0);
#endif
}
/*
* When a program attempts "storage compaction" as mentioned in the
* old malloc man page, it realloc's an already freed block. Usually
* this is the last block it freed; occasionally it might be farther
* back. We have to search all the free lists for the block in order
* to determine its bucket: 1st we make one pass thru the lists
* checking only the first block in each; if that fails we search
* ``realloc_srchlen'' blocks in each list for a match (the variable
* is extern so the caller can modify it). If that fails we just copy
* however many bytes was given to realloc() and hope it's not huge.
*/
#ifndef lint
/* 4 should be plenty, -1 =>'s whole list */
static int realloc_srchlen = 4;
#endif /* lint */
memalign_t
realloc(ptr_t cp, size_t nbytes)
{
#ifndef lint
U_int onb;
union overhead *op;
ptr_t res;
int i;
int was_alloced = 0;
if (cp == NULL)
return (malloc(nbytes));
op = (union overhead *) (((caddr_t) cp) - MEMALIGN(sizeof(union overhead)));
if (op->ov_magic == MAGIC) {
was_alloced++;
i = op->ov_index;
}
else
/*
* Already free, doing "compaction".
*
* Search for the old block of memory on the free list. First, check the
* most common case (last element free'd), then (this failing) the last
* ``realloc_srchlen'' items free'd. If all lookups fail, then assume
* the size of the memory block being realloc'd is the smallest
* possible.
*/
if ((i = findbucket(op, 1)) < 0 &&
(i = findbucket(op, realloc_srchlen)) < 0)
i = 0;
onb = MEMALIGN(nbytes + MEMALIGN(sizeof(union overhead)) + RSLOP);
/* avoid the copy if same size block */
if (was_alloced && (onb <= (U_int) (1 << (i + 3))) &&
(onb > (U_int) (1 << (i + 2)))) {
#ifdef RCHECK
/* JMR: formerly this wasn't updated ! */
nbytes = MEMALIGN(MEMALIGN(sizeof(union overhead))+nbytes+RSLOP);
*((U_int *) (((caddr_t) op) + nbytes - RSLOP)) = RMAGIC;
op->ov_rmagic = RMAGIC;
op->ov_size = (op->ov_index <= 13) ? nbytes - 1 : 0;
#endif
return ((memalign_t) cp);
}
if ((res = malloc(nbytes)) == NULL)
return ((memalign_t) NULL);
if (cp != res) { /* common optimization */
/*
* christos: this used to copy nbytes! It should copy the
* smaller of the old and new size
*/
onb = (1 << (i + 3)) - MEMALIGN(sizeof(union overhead)) - RSLOP;
(void) memmove(res, cp, onb < nbytes ? onb : nbytes);
}
if (was_alloced)
free(cp);
return ((memalign_t) res);
#else
if (cp && nbytes)
return ((memalign_t) 0);
else
return ((memalign_t) 0);
#endif /* !lint */
}
#ifndef lint
/*
* Search ``srchlen'' elements of each free list for a block whose
* header starts at ``freep''. If srchlen is -1 search the whole list.
* Return bucket number, or -1 if not found.
*/
static int
findbucket(union overhead *freep, int srchlen)
{
union overhead *p;
size_t i;
int j;
for (i = 0; i < NBUCKETS; i++) {
j = 0;
for (p = nextf[i]; p && j != srchlen; p = p->ov_next) {
if (p == freep)
return (i);
j++;
}
}
return (-1);
}
#endif
#else /* SYSMALLOC */
/**
** ``Protected versions'' of malloc, realloc, calloc, and free
**
** On many systems:
**
** 1. malloc(0) is bad
** 2. free(0) is bad
** 3. realloc(0, n) is bad
** 4. realloc(n, 0) is bad
**
** Also we call our error routine if we run out of memory.
**/
memalign_t
smalloc(size_t n)
{
ptr_t ptr;
n = n ? n : 1;
#ifdef HAVE_SBRK
if (membot == NULL)
membot = sbrk(0);
#endif /* HAVE_SBRK */
if ((ptr = malloc(n)) == NULL)
out_of_memory();
#ifndef HAVE_SBRK
if (memtop < ((char *) ptr) + n)
memtop = ((char *) ptr) + n;
if (membot == NULL)
membot = ptr;
#endif /* !HAVE_SBRK */
return ((memalign_t) ptr);
}
memalign_t
srealloc(ptr_t p, size_t n)
{
ptr_t ptr;
n = n ? n : 1;
#ifdef HAVE_SBRK
if (membot == NULL)
membot = sbrk(0);
#endif /* HAVE_SBRK */
if ((ptr = (p ? realloc(p, n) : malloc(n))) == NULL)
out_of_memory();
#ifndef HAVE_SBRK
if (memtop < ((char *) ptr) + n)
memtop = ((char *) ptr) + n;
if (membot == NULL)
membot = ptr;
#endif /* !HAVE_SBRK */
return ((memalign_t) ptr);
}
memalign_t
scalloc(size_t s, size_t n)
{
ptr_t ptr;
n *= s;
n = n ? n : 1;
#ifdef HAVE_SBRK
if (membot == NULL)
membot = sbrk(0);
#endif /* HAVE_SBRK */
if ((ptr = malloc(n)) == NULL)
out_of_memory();
memset (ptr, 0, n);
#ifndef HAVE_SBRK
if (memtop < ((char *) ptr) + n)
memtop = ((char *) ptr) + n;
if (membot == NULL)
membot = ptr;
#endif /* !HAVE_SBRK */
return ((memalign_t) ptr);
}
void
sfree(ptr_t p)
{
if (p && !dont_free)
free(p);
}
#endif /* SYSMALLOC */
/*
* mstats - print out statistics about malloc
*
* Prints two lines of numbers, one showing the length of the free list
* for each size category, the second showing the number of mallocs -
* frees for each size category.
*/
/*ARGSUSED*/
void
showall(Char **v, struct command *c)
{
#ifndef SYSMALLOC
size_t i, j;
union overhead *p;
int totfree = 0, totused = 0;
xprintf(CGETS(19, 8, "%s current memory allocation:\nfree:\t"), progname);
for (i = 0; i < NBUCKETS; i++) {
for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
continue;
xprintf(" %4zd", j);
totfree += j * (1 << (i + 3));
}
xprintf(CGETS(19, 9, "\nused:\t"));
for (i = 0; i < NBUCKETS; i++) {
xprintf(" %4d", nmalloc[i]);
totused += nmalloc[i] * (1 << (i + 3));
}
xprintf(CGETS(19, 10, "\n\tTotal in use: %d, total free: %d\n"),
totused, totfree);
xprintf(CGETS(19, 11,
"\tAllocated memory from 0x%lx to 0x%lx. Real top at 0x%lx\n"),
(unsigned long) membot, (unsigned long) memtop,
(unsigned long) sbrk(0));
#else
#ifdef HAVE_SBRK
memtop = sbrk(0);
#endif /* HAVE_SBRK */
xprintf(CGETS(19, 12, "Allocated memory from 0x%lx to 0x%lx (%ld).\n"),
(unsigned long) membot, (unsigned long) memtop,
(unsigned long) (memtop - membot));
#endif /* SYSMALLOC */
USE(c);
USE(v);
}
