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minix/lib/nbsd_libc/stdlib/malloc.c
Gianluca Guida ad4dda469f Port NetBSD libc functions to Minix. 
This patch contains changes to NetBSD libc code base to make it
compile and work on Minix. Some of them are due to actual NetBSD
libc bugs, as we're compiling it in non-reentrant mode and with
a.out support, something not exactly frequent in NetBSD.
Others are proper fixes to port it to Minix (mostly sa_len
parameter missing in socket and a few mmap from files).
2011-02-15 12:19:40 +00:00

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/* $NetBSD: malloc.c,v 1.52 2008/02/03 22:56:53 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
#ifndef __minix
# define HAS_UTRACE
# define UTRACE_LABEL
#endif /* __minix */
#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 1.52 2008/02/03 22:56:53 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 __minix
#ifndef MADV_FREE
#define MADV_FREE MADV_DONTNEED
#endif
#endif /* !__minix */
/* 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 save_errno = 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 <= 0)
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;
#ifndef __minix
case 'h': malloc_hint = 0; break;
case 'H': malloc_hint = 1; break;
#endif /* !__minix */
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 = save_errno;
}
/*
* 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);
#ifndef __minix
if (malloc_hint)
madvise(ptr, l, MADV_FREE);
#endif /* !__minix */
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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