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NetBSD/lib/libc/stdlib/malloc.c

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/* $NetBSD: malloc.c,v 1.54 2011/05/18 01:59:39 christos Exp $ */
/*
* ----------------------------------------------------------------------------
* "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
* ----------------------------------------------------------------------------
*
* From FreeBSD: malloc.c,v 1.91 2006/01/12 07:28:20 jasone
*
*/
/*
* Defining MALLOC_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
/*
* 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_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.
*
*/
#include "namespace.h"
#if defined(__FreeBSD__)
# if defined(__i386__)
# define malloc_minsize 16U
# endif
# if defined(__ia64__)
# define malloc_pageshift 13U
# define malloc_minsize 16U
# endif
# if defined(__alpha__)
# define malloc_pageshift 13U
# define malloc_minsize 16U
# endif
# if defined(__sparc64__)
# define malloc_pageshift 13U
# define malloc_minsize 16U
# endif
# if defined(__amd64__)
# define malloc_pageshift 12U
# define malloc_minsize 16U
# endif
# if defined(__arm__)
# define malloc_pageshift 12U
# define malloc_minsize 16U
# endif
# define HAS_UTRACE
# define UTRACE_LABEL
#include <sys/cdefs.h>
void utrace(struct ut *, int);
/*
* Make malloc/free/realloc thread-safe in libc for use with
* kernel threads.
*/
# include "libc_private.h"
# include "spinlock.h"
static spinlock_t thread_lock = _SPINLOCK_INITIALIZER;
# define _MALLOC_LOCK() if (__isthreaded) _SPINLOCK(&thread_lock);
# define _MALLOC_UNLOCK() if (__isthreaded) _SPINUNLOCK(&thread_lock);
#endif /* __FreeBSD__ */
#include <sys/types.h>
#if defined(__NetBSD__)
# define malloc_minsize 16U
# define HAS_UTRACE
# define UTRACE_LABEL "malloc",
#include <sys/cdefs.h>
#include "extern.h"
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: malloc.c,v 1.54 2011/05/18 01:59:39 christos Exp $");
#endif /* LIBC_SCCS and not lint */
int utrace(const char *, void *, size_t);
#include <reentrant.h>
extern int __isthreaded;
static mutex_t thread_lock = MUTEX_INITIALIZER;
#define _MALLOC_LOCK() if (__isthreaded) mutex_lock(&thread_lock);
#define _MALLOC_UNLOCK() if (__isthreaded) mutex_unlock(&thread_lock);
#endif /* __NetBSD__ */
#if defined(__sparc__) && defined(sun)
# define malloc_minsize 16U
# define MAP_ANON (0)
static int fdzero;
# define MMAP_FD fdzero
# define INIT_MMAP() \
{ if ((fdzero = open(_PATH_DEVZERO, O_RDWR, 0000)) == -1) \
wrterror("open of /dev/zero"); }
#endif /* __sparc__ */
/* Insert your combination here... */
#if defined(__FOOCPU__) && defined(__BAROS__)
# define malloc_minsize 16U
#endif /* __FOOCPU__ && __BAROS__ */
#ifndef ZEROSIZEPTR
#define ZEROSIZEPTR ((void *)(uintptr_t)(1UL << (malloc_pageshift - 1)))
#endif
/*
* No user serviceable parts behind this point.
*/
#include <sys/types.h>
#include <sys/mman.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.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 */
size_t size; /* number of bytes free */
};
/*
* How many bits per u_int in the bitmap.
* Change only if not 8 bits/byte
*/
#define MALLOC_BITS ((int)(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)
/*
* Page size related parameters, computed at run-time.
*/
static size_t malloc_pagesize;
static size_t malloc_pageshift;
static size_t malloc_pagemask;
#ifndef malloc_minsize
#define malloc_minsize 16U
#endif
#ifndef malloc_maxsize
#define malloc_maxsize ((malloc_pagesize)>>1)
#endif
#define pageround(foo) (((foo) + (malloc_pagemask))&(~(malloc_pagemask)))
#define ptr2idx(foo) \
(((size_t)(uintptr_t)(foo) >> malloc_pageshift)-malloc_origo)
#ifndef _MALLOC_LOCK
#define _MALLOC_LOCK()
#endif
#ifndef _MALLOC_UNLOCK
#define _MALLOC_UNLOCK()
#endif
#ifndef MMAP_FD
#define MMAP_FD (-1)
#endif
#ifndef INIT_MMAP
#define INIT_MMAP()
#endif
#ifndef MADV_FREE
#define MADV_FREE MADV_DONTNEED
#endif
/* Number of free pages we cache */
static size_t malloc_cache = 16;
/* The offset from pagenumber to index into the page directory */
static size_t malloc_origo;
/* The last index in the page directory we care about */
static size_t last_idx;
/* Pointer to page directory. Allocated "as if with" malloc */
static struct pginfo **page_dir;
/* How many slots in the page directory */
static size_t 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;
/* always realloc ? */
static int malloc_realloc;
/* pass the kernel a hint on free pages ? */
#if defined(MADV_FREE)
static int malloc_hint = 0;
#endif
/* 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;
#ifdef HAS_UTRACE
/* utrace ? */
static int malloc_utrace;
struct ut { void *p; size_t s; void *r; };
#define UTRACE(a, b, c) \
if (malloc_utrace) { \
struct ut u; \
u.p=a; u.s = b; u.r=c; \
utrace(UTRACE_LABEL (void *) &u, sizeof u); \
}
#else /* !HAS_UTRACE */
#define UTRACE(a,b,c)
#endif /* HAS_UTRACE */
/* my last break. */
static void *malloc_brk;
/* one location cache for free-list holders */
static struct pgfree *px;
/* compile-time options */
const char *_malloc_options;
/* Name of the current public function */
static const char *malloc_func;
/* Macro for mmap */
#define MMAP(size) \
mmap(NULL, (size), PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, \
MMAP_FD, (off_t)0);
/*
* Necessary function declarations
*/
static int extend_pgdir(size_t idx);
static void *imalloc(size_t size);
static void ifree(void *ptr);
static void *irealloc(void *ptr, size_t size);
static void
wrtmessage(const char *p1, const char *p2, const char *p3, const char *p4)
{
write(STDERR_FILENO, p1, strlen(p1));
write(STDERR_FILENO, p2, strlen(p2));
write(STDERR_FILENO, p3, strlen(p3));
write(STDERR_FILENO, p4, strlen(p4));
}
void (*_malloc_message)(const char *p1, const char *p2, const char *p3,
const char *p4) = wrtmessage;
static void
wrterror(const char *p)
{
suicide = 1;
_malloc_message(getprogname(), malloc_func, " error: ", p);
abort();
}
static void
wrtwarning(const char *p)
{
/*
* Sensitive processes, somewhat arbitrarily defined here as setuid,
* setgid, root and wheel cannot afford to have malloc mistakes.
*/
if (malloc_abort || issetugid() || getuid() == 0 || getgid() == 0)
wrterror(p);
}
/*
* Allocate a number of pages from the OS
*/
static void *
map_pages(size_t pages)
{
caddr_t result, rresult, tail;
intptr_t bytes = pages << malloc_pageshift;
if (bytes < 0 || (size_t)bytes < pages) {
errno = ENOMEM;
return NULL;
}
if ((result = sbrk(bytes)) == (void *)-1)
return NULL;
/*
* Round to a page, in case sbrk(2) did not do this for us
*/
rresult = (caddr_t)pageround((size_t)(uintptr_t)result);
if (result < rresult) {
/* make sure we have enough space to fit bytes */
if (sbrk((intptr_t)(rresult - result)) == (void *) -1) {
/* we failed, put everything back */
if (brk(result)) {
wrterror("brk(2) failed [internal error]\n");
}
}
}
tail = rresult + (size_t)bytes;
last_idx = ptr2idx(tail) - 1;
malloc_brk = tail;
if ((last_idx+1) >= malloc_ninfo && !extend_pgdir(last_idx)) {
malloc_brk = result;
last_idx = ptr2idx(malloc_brk) - 1;
/* Put back break point since we failed. */
if (brk(malloc_brk))
wrterror("brk(2) failed [internal error]\n");
return 0;
}
return rresult;
}
/*
* Extend page directory
*/
static int
extend_pgdir(size_t idx)
{
struct pginfo **new, **old;
size_t newlen, oldlen;
/* check for overflow */
if ((((~(1UL << ((sizeof(size_t) * NBBY) - 1)) / sizeof(*page_dir)) + 1)
+ (malloc_pagesize / sizeof *page_dir)) < idx) {
errno = ENOMEM;
return 0;
}
/* Make it this many pages */
newlen = pageround(idx * sizeof *page_dir) + malloc_pagesize;
/* 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 accidentally 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 = MMAP(newlen);
if (new == MAP_FAILED)
return 0;
/* Copy the old stuff */
memcpy(new, page_dir, oldlen);
/* register the new size */
malloc_ninfo = newlen / sizeof *page_dir;
/* swap the pointers */
old = page_dir;
page_dir = new;
/* Now free the old stuff */
munmap(old, oldlen);
return 1;
}
/*
* Initialize the world
*/
static void
malloc_init(void)
{
const char *p;
char b[64];
size_t i;
ssize_t j;
int serrno = errno;
/*
* Compute page-size related variables.
*/
malloc_pagesize = (size_t)sysconf(_SC_PAGESIZE);
malloc_pagemask = malloc_pagesize - 1;
for (malloc_pageshift = 0;
(1UL << malloc_pageshift) != malloc_pagesize;
malloc_pageshift++)
/* nothing */ ;
INIT_MMAP();
#ifdef MALLOC_EXTRA_SANITY
malloc_junk = 1;
#endif /* MALLOC_EXTRA_SANITY */
for (i = 0; i < 3; i++) {
if (i == 0) {
j = readlink("/etc/malloc.conf", b, sizeof b - 1);
if (j == -1)
continue;
b[j] = '\0';
p = b;
} else if (i == 1 && issetugid() == 0) {
p = getenv("MALLOC_OPTIONS");
} else if (i == 1) {
continue;
} else {
p = _malloc_options;
}
for (; p != NULL && *p != '\0'; 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 '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;
#ifdef HAS_UTRACE
case 'u': malloc_utrace = 0; break;
case 'U': malloc_utrace = 1; break;
#endif
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:
_malloc_message(getprogname(), malloc_func,
" warning: ", "unknown char in MALLOC_OPTIONS\n");
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;
/* Allocate one page for the page directory */
page_dir = MMAP(malloc_pagesize);
if (page_dir == MAP_FAILED)
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 = pageround((size_t)(uintptr_t)sbrk((intptr_t)0))
>> malloc_pageshift;
malloc_origo -= malloc_pageshift;
malloc_ninfo = malloc_pagesize / sizeof *page_dir;
/* 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 = imalloc(sizeof *px);
errno = serrno;
}
/*
* Allocate a number of complete pages
*/
static void *
malloc_pages(size_t size)
{
void *p, *delay_free = NULL;
size_t i;
struct pgfree *pf;
size_t idx;
idx = pageround(size);
if (idx < size) {
errno = ENOMEM;
return NULL;
} else
size = idx;
p = NULL;
/* Look for free pages before asking for more */
for(pf = free_list.next; pf; pf = pf->next) {
#ifdef MALLOC_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[ptr2idx(pf->page)] != MALLOC_FREE)
wrterror("(ES): non-free first page on free-list.\n");
if (page_dir[ptr2idx(pf->end)-1] != MALLOC_FREE)
wrterror("(ES): non-free last page on free-list.\n");
#endif /* MALLOC_EXTRA_SANITY */
if (pf->size < size)
continue;
if (pf->size == size) {
p = pf->page;
if (pf->next != NULL)
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 MALLOC_EXTRA_SANITY
if (p != NULL && page_dir[ptr2idx(p)] != MALLOC_FREE)
wrterror("(ES): allocated non-free page on free-list.\n");
#endif /* MALLOC_EXTRA_SANITY */
size >>= malloc_pageshift;
/* Map new pages */
if (p == NULL)
p = map_pages(size);
if (p != NULL) {
idx = ptr2idx(p);
page_dir[idx] = MALLOC_FIRST;
for (i=1;i<size;i++)
page_dir[idx+i] = MALLOC_FOLLOW;
if (malloc_junk)
memset(p, SOME_JUNK, size << malloc_pageshift);
}
if (delay_free) {
if (px == NULL)
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;
long l;
/* Allocate a new bucket */
pp = malloc_pages(malloc_pagesize);
if (pp == NULL)
return 0;
/* Find length of admin structure */
l = (long)offsetof(struct pginfo, bits[0]);
l += (long)sizeof bp->bits[0] *
(((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 = imalloc((size_t)l);
if (bp == NULL) {
ifree(pp);
return 0;
}
}
bp->size = (1<<bits);
bp->shift = bits;
bp->total = bp->free = (u_short)(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] = ~0U;
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 -= (long)(1 << bits);
}
}
/* MALLOC_LOCK */
page_dir[ptr2idx(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)
{
size_t i;
int j;
u_int u;
struct pginfo *bp;
size_t 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] == NULL && !malloc_make_chunks(j))
return NULL;
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 = NULL;
}
/* 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, (size_t)bp->size);
return (u_char *)bp->page + k;
}
/*
* Allocate a piece of memory
*/
static void *
imalloc(size_t size)
{
void *result;
if (suicide)
abort();
if ((size + malloc_pagesize) < size) /* Check for overflow */
result = NULL;
else if ((size + malloc_pagesize) >= (uintptr_t)page_dir)
result = NULL;
else if (size <= malloc_maxsize)
result = malloc_bytes(size);
else
result = malloc_pages(size);
if (malloc_abort && result == NULL)
wrterror("allocation failed.\n");
if (malloc_zero && result != NULL)
memset(result, 0, size);
return result;
}
/*
* Change the size of an allocation.
*/
static void *
irealloc(void *ptr, size_t size)
{
void *p;
size_t osize, idx;
struct pginfo **mp;
size_t i;
if (suicide)
abort();
idx = ptr2idx(ptr);
if (idx < malloc_pageshift) {
wrtwarning("junk pointer, too low to make sense.\n");
return 0;
}
if (idx > last_idx) {
wrtwarning("junk pointer, too high to make sense.\n");
return 0;
}
mp = &page_dir[idx];
if (*mp == MALLOC_FIRST) { /* Page allocation */
/* Check the pointer */
if ((size_t)(uintptr_t)ptr & malloc_pagemask) {
wrtwarning("modified (page-) pointer.\n");
return NULL;
}
/* 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, */
if (malloc_junk)
memset((u_char *)ptr + size, SOME_JUNK, osize-size);
return ptr; /* don't do anything. */
}
} else if (*mp >= MALLOC_MAGIC) { /* Chunk allocation */
/* Check the pointer for sane values */
if (((size_t)(uintptr_t)ptr & ((*mp)->size-1))) {
wrtwarning("modified (chunk-) pointer.\n");
return NULL;
}
/* Find the chunk index in the page */
i = ((size_t)(uintptr_t)ptr & malloc_pagemask) >> (*mp)->shift;
/* Verify that it isn't a free chunk already */
if ((*mp)->bits[i/MALLOC_BITS] & (1UL << (i % MALLOC_BITS))) {
wrtwarning("chunk is already free.\n");
return NULL;
}
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) */
if (malloc_junk)
memset((u_char *)ptr + size, SOME_JUNK, osize-size);
return ptr; /* ..Don't do anything */
}
} else {
wrtwarning("pointer to wrong page.\n");
return NULL;
}
p = imalloc(size);
if (p != NULL) {
/* copy the lesser of the two sizes, and free the old one */
if (!size || !osize)
;
else 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, size_t idx, struct pginfo *info)
{
size_t i;
struct pgfree *pf, *pt=NULL;
size_t 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 ((size_t)(uintptr_t)ptr & malloc_pagemask) {
wrtwarning("modified (page-) pointer.\n");
return;
}
/* Count how many pages and mark them free at the same time */
page_dir[idx] = MALLOC_FREE;
for (i = 1; page_dir[idx+i] == MALLOC_FOLLOW; i++)
page_dir[idx + 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 == NULL)
px = imalloc(sizeof *px); /* This cannot fail... */
px->page = ptr;
px->end = tail;
px->size = l;
if (free_list.next == NULL) {
/* Nothing on free list, put this at head */
px->next = free_list.next;
px->prev = &free_list;
free_list.next = px;
pf = px;
px = NULL;
} 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 != NULL;
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 = NULL;
} else if (pf->end == ptr ) {
/* Append to the previous entry */
pf->end = (char *)pf->end + l;
pf->size += l;
if (pf->next != NULL && 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 != NULL)
pf->next->prev = pf;
}
} else if (pf->page == tail) {
/* Prepend to entry */
pf->size += l;
pf->page = ptr;
} else if (pf->next == NULL) {
/* Append at tail of chain */
px->next = NULL;
px->prev = pf;
pf->next = px;
pf = px;
px = NULL;
} else {
wrterror("freelist is destroyed.\n");
}
}
/* Return something to OS ? */
if (pf->next == NULL && /* 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((intptr_t)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;
idx = ptr2idx(pf->end);
for(i=idx;i <= last_idx;)
page_dir[i++] = MALLOC_NOT_MINE;
last_idx = idx - 1;
/* XXX: We could realloc/shrink the pagedir here I guess. */
}
if (pt != NULL)
ifree(pt);
}
/*
* Free a chunk, and possibly the page it's on, if the page becomes empty.
*/
static inline void
free_bytes(void *ptr, size_t idx, struct pginfo *info)
{
size_t i;
struct pginfo **mp;
void *vp;
/* Find the chunk number on the page */
i = ((size_t)(uintptr_t)ptr & malloc_pagemask) >> info->shift;
if (((size_t)(uintptr_t)ptr & (info->size-1))) {
wrtwarning("modified (chunk-) pointer.\n");
return;
}
if (info->bits[i/MALLOC_BITS] & (1UL << (i % MALLOC_BITS))) {
wrtwarning("chunk is already free.\n");
return;
}
if (malloc_junk)
memset(ptr, SOME_JUNK, (size_t)info->size);
info->bits[i/MALLOC_BITS] |= (u_int)(1UL << (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 MALLOC_EXTRA_SANITY
if (!*mp)
wrterror("(ES): Not on queue.\n");
#endif /* MALLOC_EXTRA_SANITY */
}
*mp = info->next;
/* Free the page & the info structure if need be */
page_dir[idx] = MALLOC_FIRST;
vp = info->page; /* Order is important ! */
if(vp != (void*)info)
ifree(info);
ifree(vp);
}
static void
ifree(void *ptr)
{
struct pginfo *info;
size_t idx;
/* This is legal */
if (ptr == NULL)
return;
/* If we're already sinking, don't make matters any worse. */
if (suicide)
return;
idx = ptr2idx(ptr);
if (idx < malloc_pageshift) {
wrtwarning("junk pointer, too low to make sense.\n");
return;
}
if (idx > last_idx) {
wrtwarning("junk pointer, too high to make sense.\n");
return;
}
info = page_dir[idx];
if (info < MALLOC_MAGIC)
free_pages(ptr, idx, info);
else
free_bytes(ptr, idx, info);
return;
}
static int malloc_active; /* Recusion flag for public interface. */
static unsigned malloc_started; /* Set when initialization has been done */
static void *
pubrealloc(void *ptr, size_t size, const char *func)
{
void *r;
int err = 0;
/*
* If a thread is inside our code with a functional lock held, and then
* catches a signal which calls us again, we would get a deadlock if the
* lock is not of a recursive type.
*/
_MALLOC_LOCK();
malloc_func = func;
if (malloc_active > 0) {
if (malloc_active == 1) {
wrtwarning("recursive call\n");
malloc_active = 2;
}
_MALLOC_UNLOCK();
errno = EINVAL;
return (NULL);
}
malloc_active = 1;
if (!malloc_started) {
if (ptr != NULL) {
wrtwarning("malloc() has never been called\n");
malloc_active = 0;
_MALLOC_UNLOCK();
errno = EINVAL;
return (NULL);
}
malloc_init();
malloc_started = 1;
}
if (ptr == ZEROSIZEPTR)
ptr = NULL;
if (malloc_sysv && !size) {
if (ptr != NULL)
ifree(ptr);
r = NULL;
} else if (!size) {
if (ptr != NULL)
ifree(ptr);
r = ZEROSIZEPTR;
} else if (ptr == NULL) {
r = imalloc(size);
err = (r == NULL);
} else {
r = irealloc(ptr, size);
err = (r == NULL);
}
UTRACE(ptr, size, r);
malloc_active = 0;
_MALLOC_UNLOCK();
if (malloc_xmalloc && err)
wrterror("out of memory\n");
if (err)
errno = ENOMEM;
return (r);
}
/*
* These are the public exported interface routines.
*/
void *
malloc(size_t size)
{
return pubrealloc(NULL, size, " in malloc():");
}
int
posix_memalign(void **memptr, size_t alignment, size_t size)
{
int err;
void *result;
if (!malloc_started) {
malloc_init();
malloc_started = 1;
}
/* Make sure that alignment is a large enough power of 2. */
if (((alignment - 1) & alignment) != 0 || alignment < sizeof(void *) ||
alignment > malloc_pagesize)
return EINVAL;
/*
* (size | alignment) is enough to assure the requested alignment, since
* the allocator always allocates power-of-two blocks.
*/
err = errno; /* Protect errno against changes in pubrealloc(). */
result = pubrealloc(NULL, (size | alignment), " in posix_memalign()");
errno = err;
if (result == NULL)
return ENOMEM;
*memptr = result;
return 0;
}
void *
calloc(size_t num, size_t size)
{
void *ret;
if (size != 0 && (num * size) / size != num) {
/* size_t overflow. */
errno = ENOMEM;
return (NULL);
}
ret = pubrealloc(NULL, num * size, " in calloc():");
if (ret != NULL)
memset(ret, 0, num * size);
return ret;
}
void
free(void *ptr)
{
pubrealloc(ptr, 0, " in free():");
}
void *
realloc(void *ptr, size_t size)
{
return pubrealloc(ptr, size, " in realloc():");
}
/*
* Begin library-private functions, used by threading libraries for protection
* of malloc during fork(). These functions are only called if the program is
* running in threaded mode, so there is no need to check whether the program
* is threaded here.
*/
void
_malloc_prefork(void)
{
_MALLOC_LOCK();
}
void
_malloc_postfork(void)
{
_MALLOC_UNLOCK();
}
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