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7c5232c617
freebsd/lib/libc/stdlib/malloc.c
Poul-Henning Kamp 7c5232c617 Add yet an option, this time on how to deal with malloc(0) and realloc(ptr.0) 
Prompted by:	X11 & XFree86
1997-06-12 12:45:45 +00:00

1199 lines
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/*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
* ----------------------------------------------------------------------------
*
* $Id: malloc.c,v 1.24 1997/06/04 12:55:49 jb Exp $
*
*/
/*
* Defining EXTRA_SANITY will enable extra checks which are related
* to internal conditions and consistency in malloc.c. This has a
* noticeable runtime performance hit, and generally will not do you
* any good unless you fiddle with the internals of malloc or want
* to catch random pointer corruption as early as possible.
*/
#ifndef MALLOC_EXTRA_SANITY
#undef MALLOC_EXTRA_SANITY
#endif
/*
* Defining MALLOC_STATS will enable you to call malloc_dump() and set
* the [dD] options in the MALLOC_OPTIONS environment variable.
* It has no run-time performance hit.
*/
#ifndef MALLOC_STATS
#undef MALLOC_STATS
#endif
/*
* What to use for Junk. This is the byte value we use to fill with
* when the 'J' option is enabled.
*/
#define SOME_JUNK 0xd0 /* as in "Duh" :-) */
/*
* The basic parameters you can tweak.
*
* malloc_pageshift pagesize = 1 << malloc_pageshift
* It's probably best if this is the native
* page size, but it shouldn't have to be.
*
* malloc_minsize minimum size of an allocation in bytes.
* If this is too small it's too much work
* to manage them. This is also the smallest
* unit of alignment used for the storage
* returned by malloc/realloc.
*
*/
#if defined(__i386__) && defined(__FreeBSD__)
# define malloc_pageshift 12U
# define malloc_minsize 16U
#endif /* __i386__ && __FreeBSD__ */
#if defined(__sparc__)
# define malloc_pageshirt 12U
# define malloc_minsize 16U
# define MAP_ANON (0)
# define USE_DEV_ZERO
# define MADV_FREE MADV_DONTNEED
#endif /* __sparc__ */
/* Insert your combination here... */
#if defined(__FOOCPU__) && defined(__BAROS__)
# define malloc_pageshift 12U
# define malloc_minsize 16U
#endif /* __i386__ && __FreeBSD__ */
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
static struct pthread_mutex _malloc_lock = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t malloc_lock = &_malloc_lock;
#define THREAD_LOCK() pthread_mutex_lock(&malloc_lock)
#define THREAD_UNLOCK() pthread_mutex_unlock(&malloc_lock)
#else
#define THREAD_LOCK()
#define THREAD_UNLOCK()
#endif
/*
* No user serviceable parts behind this point.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/mman.h>
/*
* This structure describes a page worth of chunks.
*/
struct pginfo {
struct pginfo *next; /* next on the free list */
void *page; /* Pointer to the page */
u_short size; /* size of this page's chunks */
u_short shift; /* How far to shift for this size chunks */
u_short free; /* How many free chunks */
u_short total; /* How many chunk */
u_int bits[1]; /* Which chunks are free */
};
/*
* This structure describes a number of free pages.
*/
struct pgfree {
struct pgfree *next; /* next run of free pages */
struct pgfree *prev; /* prev run of free pages */
void *page; /* pointer to free pages */
void *end; /* pointer to end of free pages */
u_long size; /* number of bytes free */
};
/*
* How many bits per u_int in the bitmap.
* Change only if not 8 bits/byte
*/
#define MALLOC_BITS (8*sizeof(u_int))
/*
* Magic values to put in the page_directory
*/
#define MALLOC_NOT_MINE ((struct pginfo*) 0)
#define MALLOC_FREE ((struct pginfo*) 1)
#define MALLOC_FIRST ((struct pginfo*) 2)
#define MALLOC_FOLLOW ((struct pginfo*) 3)
#define MALLOC_MAGIC ((struct pginfo*) 4)
#ifndef malloc_pageshift
#define malloc_pageshift 12U
#endif
#ifndef malloc_minsize
#define malloc_minsize 16U
#endif
#ifndef malloc_pageshift
#error "malloc_pageshift undefined"
#endif
#if !defined(malloc_pagesize)
#define malloc_pagesize (1U<<malloc_pageshift)
#endif
#if ((1<<malloc_pageshift) != malloc_pagesize)
#error "(1<<malloc_pageshift) != malloc_pagesize"
#endif
#ifndef malloc_maxsize
#define malloc_maxsize ((malloc_pagesize)>>1)
#endif
/* A mask for the offset inside a page. */
#define malloc_pagemask ((malloc_pagesize)-1)
#define pageround(foo) (((foo) + (malloc_pagemask))&(~(malloc_pagemask)))
#define ptr2index(foo) (((u_long)(foo) >> malloc_pageshift)-malloc_origo)
/* fd of /dev/zero */
#ifdef USE_DEV_ZERO
static int fdzero;
#define MMAP_FD fdzero
#define INIT_MMAP() \
{ if ((fdzero=open("/dev/zero", O_RDWR, 0000)) == -1) \
wrterror("open of /dev/zero"); }
#else
#define MMAP_FD (-1)
#define INIT_MMAP()
#endif
/* Set when initialization has been done */
static unsigned malloc_started;
/* Number of free pages we cache */
static unsigned malloc_cache = 16;
/* The offset from pagenumber to index into the page directory */
static u_long malloc_origo;
/* The last index in the page directory we care about */
static u_long last_index;
/* Pointer to page directory. Allocated "as if with" malloc */
static struct pginfo **page_dir;
/* How many slots in the page directory */
static unsigned malloc_ninfo;
/* Free pages line up here */
static struct pgfree free_list;
/* Abort(), user doesn't handle problems. */
static int malloc_abort;
/* Are we trying to die ? */
static int suicide;
/* dump statistics */
static int malloc_stats;
/* always realloc ? */
static int malloc_realloc;
/* pass the kernel a hint on free pages ? */
static int malloc_hint;
/* xmalloc behaviour ? */
static int malloc_xmalloc;
/* sysv behaviour for malloc(0) ? */
static int malloc_sysv;
/* zero fill ? */
static int malloc_zero;
/* junk fill ? */
static int malloc_junk;
/* utrace ? */
static int malloc_utrace;
#ifdef __FreeBSD__
struct ut { void *p; size_t s; void *r; };
void utrace __P((struct ut *, int));
#define UTRACE(a, b, c) \
if (malloc_utrace) \
{struct ut u; u.p=a; u.s = b; u.r=c; utrace(&u, sizeof u);}
#else /* !__FreeBSD__ */
#define UTRACE(a,b,c)
#endif
/* my last break. */
static void *malloc_brk;
/* one location cache for free-list holders */
static struct pgfree *px;
/* compile-time options */
char *malloc_options;
/* Name of the current public function */
static char *malloc_func;
/* Macro for mmap */
#define MMAP(size) \
mmap((caddr_t)0, (size), PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, \
MMAP_FD, 0);
/*
* Necessary function declarations
*/
static int extend_pgdir(u_long index);
static void *imalloc(size_t size);
static void ifree(void *ptr);
static void *irealloc(void *ptr, size_t size);
#ifdef MALLOC_STATS
void
malloc_dump(FILE *fd)
{
struct pginfo **pd;
struct pgfree *pf;
int j;
pd = page_dir;
/* print out all the pages */
for(j=0;j<=last_index;j++) {
fprintf(fd, "%08lx %5d ", (j+malloc_origo) << malloc_pageshift, j);
if (pd[j] == MALLOC_NOT_MINE) {
for(j++;j<=last_index && pd[j] == MALLOC_NOT_MINE;j++)
;
j--;
fprintf(fd, ".. %5d not mine\n", j);
} else if (pd[j] == MALLOC_FREE) {
for(j++;j<=last_index && pd[j] == MALLOC_FREE;j++)
;
j--;
fprintf(fd, ".. %5d free\n", j);
} else if (pd[j] == MALLOC_FIRST) {
for(j++;j<=last_index && pd[j] == MALLOC_FOLLOW;j++)
;
j--;
fprintf(fd, ".. %5d in use\n", j);
} else if (pd[j] < MALLOC_MAGIC) {
fprintf(fd, "(%p)\n", pd[j]);
} else {
fprintf(fd, "%p %d (of %d) x %d @ %p --> %p\n",
pd[j], pd[j]->free, pd[j]->total,
pd[j]->size, pd[j]->page, pd[j]->next);
}
}
for(pf=free_list.next; pf; pf=pf->next) {
fprintf(fd, "Free: @%p [%p...%p[ %ld ->%p <-%p\n",
pf, pf->page, pf->end, pf->size, pf->prev, pf->next);
if (pf == pf->next) {
fprintf(fd, "Free_list loops.\n");
break;
}
}
/* print out various info */
fprintf(fd, "Minsize\t%d\n", malloc_minsize);
fprintf(fd, "Maxsize\t%d\n", malloc_maxsize);
fprintf(fd, "Pagesize\t%d\n", malloc_pagesize);
fprintf(fd, "Pageshift\t%d\n", malloc_pageshift);
fprintf(fd, "FirstPage\t%ld\n", malloc_origo);
fprintf(fd, "LastPage\t%ld %lx\n", last_index+malloc_pageshift,
(last_index + malloc_pageshift) << malloc_pageshift);
fprintf(fd, "Break\t%ld\n", (u_long)sbrk(0) >> malloc_pageshift);
}
#endif /* MALLOC_STATS */
extern char *__progname;
static void
wrterror(char *p)
{
char *q = " error: ";
write(2, __progname, strlen(__progname));
write(2, malloc_func, strlen(malloc_func));
write(2, q, strlen(q));
write(2, p, strlen(p));
suicide = 1;
#ifdef MALLOC_STATS
if (malloc_stats)
malloc_dump(stderr);
#endif /* MALLOC_STATS */
abort();
}
static void
wrtwarning(char *p)
{
char *q = " warning: ";
if (malloc_abort)
wrterror(p);
write(2, __progname, strlen(__progname));
write(2, malloc_func, strlen(malloc_func));
write(2, q, strlen(q));
write(2, p, strlen(p));
}
#ifdef MALLOC_STATS
static void
malloc_exit()
{
FILE *fd = fopen("malloc.out", "a");
char *q = "malloc() warning: Couldn't dump stats.\n";
if (fd) {
malloc_dump(fd);
fclose(fd);
} else
write(2, q, strlen(q));
}
#endif /* MALLOC_STATS */
/*
* Allocate a number of pages from the OS
*/
static caddr_t
map_pages(int pages)
{
caddr_t result, tail;
result = (caddr_t)pageround((u_long)sbrk(0));
tail = result + (pages << malloc_pageshift);
if (brk(tail)) {
#ifdef EXTRA_SANITY
wrterror("(ES): map_pages fails\n");
#endif /* EXTRA_SANITY */
return 0;
}
last_index = ptr2index(tail) - 1;
malloc_brk = tail;
if ((last_index+1) >= malloc_ninfo && !extend_pgdir(last_index))
return 0;;
return result;
}
/*
* Extend page directory
*/
static int
extend_pgdir(u_long index)
{
struct pginfo **new, **old;
int i, oldlen;
/* Make it this many pages */
i = index * sizeof *page_dir;
i /= malloc_pagesize;
i += 2;
/* remember the old mapping size */
oldlen = malloc_ninfo * sizeof *page_dir;
/*
* NOTE: we allocate new pages and copy the directory rather than tempt
* fate by trying to "grow" the region.. There is nothing to prevent
* us from accidently re-mapping space that's been allocated by our caller
* via dlopen() or other mmap().
*
* The copy problem is not too bad, as there is 4K of page index per
* 4MB of malloc arena.
*
* We can totally avoid the copy if we open a file descriptor to associate
* the anon mappings with. Then, when we remap the pages at the new
* address, the old pages will be "magically" remapped.. But this means
* keeping open a "secret" file descriptor.....
*/
/* Get new pages */
new = (struct pginfo**) MMAP(i * malloc_pagesize);
if (new == (struct pginfo **)-1)
return 0;
/* Copy the old stuff */
memcpy(new, page_dir,
malloc_ninfo * sizeof *page_dir);
/* register the new size */
malloc_ninfo = i * malloc_pagesize / sizeof *page_dir;
/* swap the pointers */
old = page_dir;
page_dir = new;
/* Now free the old stuff */
munmap((caddr_t)old, oldlen);
return 1;
}
/*
* Initialize the world
*/
static void
malloc_init ()
{
char *p, b[64];
int i, j;
INIT_MMAP();
#ifdef EXTRA_SANITY
malloc_junk = 1;
#endif /* EXTRA_SANITY */
for (i = 0; i < 3; i++) {
if (i == 0) {
j = readlink("/etc/malloc.conf", b, sizeof b - 1);
if (j <= 0)
continue;
b[j] = '\0';
p = b;
} else if (i == 1) {
p = getenv("MALLOC_OPTIONS");
} else {
p = malloc_options;
}
for (; p && *p; p++) {
switch (*p) {
case '>': malloc_cache <<= 1; break;
case '<': malloc_cache >>= 1; break;
case 'a': malloc_abort = 0; break;
case 'A': malloc_abort = 1; break;
case 'd': malloc_stats = 0; break;
case 'D': malloc_stats = 1; break;
case 'h': malloc_hint = 0; break;
case 'H': malloc_hint = 1; break;
case 'r': malloc_realloc = 0; break;
case 'R': malloc_realloc = 1; break;
case 'j': malloc_junk = 0; break;
case 'J': malloc_junk = 1; break;
case 'u': malloc_utrace = 0; break;
case 'U': malloc_utrace = 1; break;
case 'v': malloc_sysv = 0; break;
case 'V': malloc_sysv = 1; break;
case 'x': malloc_xmalloc = 0; break;
case 'X': malloc_xmalloc = 1; break;
case 'z': malloc_zero = 0; break;
case 'Z': malloc_zero = 1; break;
default:
j = malloc_abort;
malloc_abort = 0;
wrtwarning("unknown char in MALLOC_OPTIONS\n");
malloc_abort = j;
break;
}
}
}
UTRACE(0, 0, 0);
/*
* We want junk in the entire allocation, and zero only in the part
* the user asked for.
*/
if (malloc_zero)
malloc_junk=1;
#ifdef MALLOC_STATS
if (malloc_stats)
atexit(malloc_exit);
#endif /* MALLOC_STATS */
/* Allocate one page for the page directory */
page_dir = (struct pginfo **) MMAP(malloc_pagesize);
if (page_dir == (struct pginfo **) -1)
wrterror("mmap(2) failed, check limits.\n");
/*
* We need a maximum of malloc_pageshift buckets, steal these from the
* front of the page_directory;
*/
malloc_origo = ((u_long)pageround((u_long)sbrk(0))) >> malloc_pageshift;
malloc_origo -= malloc_pageshift;
malloc_ninfo = malloc_pagesize / sizeof *page_dir;
/* Been here, done that */
malloc_started++;
/* Recalculate the cache size in bytes, and make sure it's nonzero */
if (!malloc_cache)
malloc_cache++;
malloc_cache <<= malloc_pageshift;
/*
* This is a nice hack from Kaleb Keithly (kaleb@x.org).
* We can sbrk(2) further back when we keep this on a low address.
*/
px = (struct pgfree *) imalloc (sizeof *px);
}
/*
* Allocate a number of complete pages
*/
static void *
malloc_pages(size_t size)
{
void *p, *delay_free = 0;
int i;
struct pgfree *pf;
u_long index;
size = pageround(size);
p = 0;
/* Look for free pages before asking for more */
for(pf = free_list.next; pf; pf = pf->next) {
#ifdef EXTRA_SANITY
if (pf->size & malloc_pagemask)
wrterror("(ES): junk length entry on free_list\n");
if (!pf->size)
wrterror("(ES): zero length entry on free_list\n");
if (pf->page == pf->end)
wrterror("(ES): zero entry on free_list\n");
if (pf->page > pf->end)
wrterror("(ES): sick entry on free_list\n");
if ((void*)pf->page >= (void*)sbrk(0))
wrterror("(ES): entry on free_list past brk\n");
if (page_dir[ptr2index(pf->page)] != MALLOC_FREE)
wrterror("(ES): non-free first page on free-list\n");
if (page_dir[ptr2index(pf->end)-1] != MALLOC_FREE)
wrterror("(ES): non-free last page on free-list\n");
#endif /* EXTRA_SANITY */
if (pf->size < size)
continue;
if (pf->size == size) {
p = pf->page;
if (pf->next)
pf->next->prev = pf->prev;
pf->prev->next = pf->next;
delay_free = pf;
break;
}
p = pf->page;
pf->page = (char *)pf->page + size;
pf->size -= size;
break;
}
#ifdef EXTRA_SANITY
if (p && page_dir[ptr2index(p)] != MALLOC_FREE)
wrterror("(ES): allocated non-free page on free-list\n");
#endif /* EXTRA_SANITY */
size >>= malloc_pageshift;
/* Map new pages */
if (!p)
p = map_pages(size);
if (p) {
index = ptr2index(p);
page_dir[index] = MALLOC_FIRST;
for (i=1;i<size;i++)
page_dir[index+i] = MALLOC_FOLLOW;
if (malloc_junk)
memset(p, SOME_JUNK, size << malloc_pageshift);
}
if (delay_free) {
if (!px)
px = delay_free;
else
ifree(delay_free);
}
return p;
}
/*
* Allocate a page of fragments
*/
static __inline__ int
malloc_make_chunks(int bits)
{
struct pginfo *bp;
void *pp;
int i, k, l;
/* Allocate a new bucket */
pp = malloc_pages(malloc_pagesize);
if (!pp)
return 0;
/* Find length of admin structure */
l = sizeof *bp - sizeof(u_long);
l += sizeof(u_long) *
(((malloc_pagesize >> bits)+MALLOC_BITS-1) / MALLOC_BITS);
/* Don't waste more than two chunks on this */
if ((1<<(bits)) <= l+l) {
bp = (struct pginfo *)pp;
} else {
bp = (struct pginfo *)imalloc(l);
if (!bp) {
ifree(pp);
return 0;
}
}
bp->size = (1<<bits);
bp->shift = bits;
bp->total = bp->free = malloc_pagesize >> bits;
bp->page = pp;
/* set all valid bits in the bitmap */
k = bp->total;
i = 0;
/* Do a bunch at a time */
for(;k-i >= MALLOC_BITS; i += MALLOC_BITS)
bp->bits[i / MALLOC_BITS] = ~0;
for(; i < k; i++)
bp->bits[i/MALLOC_BITS] |= 1<<(i%MALLOC_BITS);
if (bp == bp->page) {
/* Mark the ones we stole for ourselves */
for(i=0;l > 0;i++) {
bp->bits[i/MALLOC_BITS] &= ~(1<<(i%MALLOC_BITS));
bp->free--;
bp->total--;
l -= (1 << bits);
}
}
/* MALLOC_LOCK */
page_dir[ptr2index(pp)] = bp;
bp->next = page_dir[bits];
page_dir[bits] = bp;
/* MALLOC_UNLOCK */
return 1;
}
/*
* Allocate a fragment
*/
static void *
malloc_bytes(size_t size)
{
int i,j;
u_int u;
struct pginfo *bp;
int k;
u_int *lp;
/* Don't bother with anything less than this */
if (size < malloc_minsize)
size = malloc_minsize;
/* Find the right bucket */
j = 1;
i = size-1;
while (i >>= 1)
j++;
/* If it's empty, make a page more of that size chunks */
if (!page_dir[j] && !malloc_make_chunks(j))
return 0;
bp = page_dir[j];
/* Find first word of bitmap which isn't empty */
for (lp = bp->bits; !*lp; lp++)
;
/* Find that bit, and tweak it */
u = 1;
k = 0;
while (!(*lp & u)) {
u += u;
k++;
}
*lp ^= u;
/* If there are no more free, remove from free-list */
if (!--bp->free) {
page_dir[j] = bp->next;
bp->next = 0;
}
/* Adjust to the real offset of that chunk */
k += (lp-bp->bits)*MALLOC_BITS;
k <<= bp->shift;
if (malloc_junk)
memset((u_char*)bp->page + k, SOME_JUNK, bp->size);
return (u_char *)bp->page + k;
}
/*
* Allocate a piece of memory
*/
static void *
imalloc(size_t size)
{
void *result;
if (!malloc_started)
malloc_init();
if (suicide)
abort();
if (malloc_sysv && !size)
result = 0;
else if ((size + malloc_pagesize) < size) /* Check for overflow */
result = 0;
else if (size <= malloc_maxsize)
result = malloc_bytes(size);
else
result = malloc_pages(size);
if (malloc_abort && !result)
wrterror("allocation failed.\n");
if (malloc_zero && result)
memset(result, 0, size);
return result;
}
/*
* Change the size of an allocation.
*/
static void *
irealloc(void *ptr, size_t size)
{
void *p;
u_long osize, index;
struct pginfo **mp;
int i;
if (suicide)
abort();
if (!malloc_started) {
wrtwarning("malloc() has never been called.\n");
return 0;
}
index = ptr2index(ptr);
if (index < malloc_pageshift) {
wrtwarning("junk pointer, too low to make sense.\n");
return 0;
}
if (index > last_index) {
wrtwarning("junk pointer, too high to make sense.\n");
return 0;
}
mp = &page_dir[index];
if (*mp == MALLOC_FIRST) { /* Page allocation */
/* Check the pointer */
if ((u_long)ptr & malloc_pagemask) {
wrtwarning("modified (page-) pointer.\n");
return 0;
}
/* Find the size in bytes */
for (osize = malloc_pagesize; *++mp == MALLOC_FOLLOW;)
osize += malloc_pagesize;
if (!malloc_realloc && /* unless we have to, */
size <= osize && /* .. or are too small, */
size > (osize - malloc_pagesize)) { /* .. or can free a page, */
return ptr; /* don't do anything. */
}
} else if (*mp >= MALLOC_MAGIC) { /* Chunk allocation */
/* Check the pointer for sane values */
if (((u_long)ptr & ((*mp)->size-1))) {
wrtwarning("modified (chunk-) pointer.\n");
return 0;
}
/* Find the chunk index in the page */
i = ((u_long)ptr & malloc_pagemask) >> (*mp)->shift;
/* Verify that it isn't a free chunk already */
if ((*mp)->bits[i/MALLOC_BITS] & (1<<(i%MALLOC_BITS))) {
wrtwarning("chunk is already free.\n");
return 0;
}
osize = (*mp)->size;
if (!malloc_realloc && /* Unless we have to, */
size < osize && /* ..or are too small, */
(size > osize/2 || /* ..or could use a smaller size, */
osize == malloc_minsize)) { /* ..(if there is one) */
return ptr; /* ..Don't do anything */
}
} else {
wrtwarning("pointer to wrong page.\n");
return 0;
}
p = imalloc(size);
if (p) {
/* copy the lesser of the two sizes, and free the old one */
if (osize < size)
memcpy(p, ptr, osize);
else
memcpy(p, ptr, size);
ifree(ptr);
}
return p;
}
/*
* Free a sequence of pages
*/
static __inline__ void
free_pages(void *ptr, int index, struct pginfo *info)
{
int i;
struct pgfree *pf, *pt=0;
u_long l;
void *tail;
if (info == MALLOC_FREE) {
wrtwarning("page is already free.\n");
return;
}
if (info != MALLOC_FIRST) {
wrtwarning("pointer to wrong page.\n");
return;
}
if ((u_long)ptr & malloc_pagemask) {
wrtwarning("modified (page-) pointer.\n");
return;
}
/* Count how many pages and mark them free at the same time */
page_dir[index] = MALLOC_FREE;
for (i = 1; page_dir[index+i] == MALLOC_FOLLOW; i++)
page_dir[index + i] = MALLOC_FREE;
l = i << malloc_pageshift;
if (malloc_junk)
memset(ptr, SOME_JUNK, l);
if (malloc_hint)
madvise(ptr, l, MADV_FREE);
tail = (char *)ptr+l;
/* add to free-list */
if (!px)
px = imalloc(sizeof *pt); /* This cannot fail... */
px->page = ptr;
px->end = tail;
px->size = l;
if (!free_list.next) {
/* Nothing on free list, put this at head */
px->next = free_list.next;
px->prev = &free_list;
free_list.next = px;
pf = px;
px = 0;
} else {
/* Find the right spot, leave pf pointing to the modified entry. */
tail = (char *)ptr+l;
for(pf = free_list.next; pf->end < ptr && pf->next; pf = pf->next)
; /* Race ahead here */
if (pf->page > tail) {
/* Insert before entry */
px->next = pf;
px->prev = pf->prev;
pf->prev = px;
px->prev->next = px;
pf = px;
px = 0;
} else if (pf->end == ptr ) {
/* Append to the previous entry */
pf->end = (char *)pf->end + l;
pf->size += l;
if (pf->next && pf->end == pf->next->page ) {
/* And collapse the next too. */
pt = pf->next;
pf->end = pt->end;
pf->size += pt->size;
pf->next = pt->next;
if (pf->next)
pf->next->prev = pf;
}
} else if (pf->page == tail) {
/* Prepend to entry */
pf->size += l;
pf->page = ptr;
} else if (!pf->next) {
/* Append at tail of chain */
px->next = 0;
px->prev = pf;
pf->next = px;
pf = px;
px = 0;
} else {
wrterror("freelist is destroyed.\n");
}
}
/* Return something to OS ? */
if (!pf->next && /* If we're the last one, */
pf->size > malloc_cache && /* ..and the cache is full, */
pf->end == malloc_brk && /* ..and none behind us, */
malloc_brk == sbrk(0)) { /* ..and it's OK to do... */
/*
* Keep the cache intact. Notice that the '>' above guarantees that
* the pf will always have at least one page afterwards.
*/
pf->end = (char *)pf->page + malloc_cache;
pf->size = malloc_cache;
brk(pf->end);
malloc_brk = pf->end;
index = ptr2index(pf->end);
last_index = index - 1;
for(i=index;i <= last_index;)
page_dir[i++] = MALLOC_NOT_MINE;
/* XXX: We could realloc/shrink the pagedir here I guess. */
}
if (pt)
ifree(pt);
}
/*
* Free a chunk, and possibly the page it's on, if the page becomes empty.
*/
static __inline__ void
free_bytes(void *ptr, int index, struct pginfo *info)
{
int i;
struct pginfo **mp;
void *vp;
/* Find the chunk number on the page */
i = ((u_long)ptr & malloc_pagemask) >> info->shift;
if (((u_long)ptr & (info->size-1))) {
wrtwarning("modified (chunk-) pointer.\n");
return;
}
if (info->bits[i/MALLOC_BITS] & (1<<(i%MALLOC_BITS))) {
wrtwarning("chunk is already free.\n");
return;
}
if (malloc_junk)
memset(ptr, SOME_JUNK, info->size);
info->bits[i/MALLOC_BITS] |= 1<<(i%MALLOC_BITS);
info->free++;
mp = page_dir + info->shift;
if (info->free == 1) {
/* Page became non-full */
mp = page_dir + info->shift;
/* Insert in address order */
while (*mp && (*mp)->next && (*mp)->next->page < info->page)
mp = &(*mp)->next;
info->next = *mp;
*mp = info;
return;
}
if (info->free != info->total)
return;
/* Find & remove this page in the queue */
while (*mp != info) {
mp = &((*mp)->next);
#ifdef EXTRA_SANITY
if (!*mp)
wrterror("(ES): Not on queue\n");
#endif /* EXTRA_SANITY */
}
*mp = info->next;
/* Free the page & the info structure if need be */
page_dir[ptr2index(info->page)] = MALLOC_FIRST;
vp = info->page; /* Order is important ! */
if(vp != (void*)info)
ifree(info);
ifree(vp);
}
static void
ifree(void *ptr)
{
struct pginfo *info;
int index;
/* This is legal */
if (!ptr)
return;
if (!malloc_started) {
wrtwarning("malloc() has never been called.\n");
return;
}
/* If we're already sinking, don't make matters any worse. */
if (suicide)
return;
index = ptr2index(ptr);
if (index < malloc_pageshift) {
wrtwarning("junk pointer, too low to make sense.\n");
return;
}
if (index > last_index) {
wrtwarning("junk pointer, too high to make sense.\n");
return;
}
info = page_dir[index];
if (info < MALLOC_MAGIC)
free_pages(ptr, index, info);
else
free_bytes(ptr, index, info);
return;
}
/*
* These are the public exported interface routines.
*/
static int malloc_active;
void *
malloc(size_t size)
{
register void *r;
malloc_func = " in malloc():";
THREAD_LOCK();
if (malloc_active++) {
wrtwarning("recursive call.\n");
malloc_active--;
return (0);
}
r = imalloc(size);
UTRACE(0, size, r);
malloc_active--;
THREAD_UNLOCK();
if (malloc_xmalloc && !r)
wrterror("out of memory.\n");
return (r);
}
void
free(void *ptr)
{
malloc_func = " in free():";
THREAD_LOCK();
if (malloc_active++) {
wrtwarning("recursive call.\n");
malloc_active--;
return;
}
ifree(ptr);
UTRACE(ptr, 0, 0);
malloc_active--;
THREAD_UNLOCK();
return;
}
void *
realloc(void *ptr, size_t size)
{
register void *r;
malloc_func = " in realloc():";
THREAD_LOCK();
if (malloc_active++) {
wrtwarning("recursive call.\n");
malloc_active--;
return (0);
}
if (!ptr) {
r = imalloc(size);
} else {
r = irealloc(ptr, size);
}
UTRACE(ptr, size, r);
malloc_active--;
THREAD_UNLOCK();
if (malloc_xmalloc && !r)
wrterror("out of memory.\n");
return (r);
}
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