/*
* ----------------------------------------------------------------------------
* "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
* ----------------------------------------------------------------------------
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$OpenBSD: malloc.c,v 1.66 2004/02/19 23:20:53 tdeval Exp $";
#endif /* LIBC_SCCS and not lint */
/*
* 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
/*
* 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, but does pull in stdio...
*/
#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" :-) */
#include <sys/types.h>
#include <sys/param.h>
#include <sys/mman.h>
#include <sys/uio.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>
#include <errno.h>
#include "thread_private.h"
/*
* 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(__OpenBSD__) && defined(__sparc__)
# define malloc_pageshift 13U
#endif /* __OpenBSD__ */
/*
* No user serviceable parts behind this point.
*
* 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_long 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_long in the bitmap.
* Change only if not 8 bits/byte
*/
#define MALLOC_BITS (8*sizeof(u_long))
/*
* 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 (PGSHIFT)
#endif
#ifndef malloc_minsize
#define malloc_minsize 16U
#endif
#ifndef malloc_pageshift
#error "malloc_pageshift undefined"
#endif
#if !defined(malloc_pagesize)
#define malloc_pagesize (1UL<<malloc_pageshift)
#endif
#if ((1UL<<malloc_pageshift) != malloc_pagesize)
#error "(1UL<<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\n"); }
#else
#define MMAP_FD (-1)
#define INIT_MMAP()
#endif
/* Set when initialization has been done */
static unsigned int malloc_started;
/* Number of free pages we cache */
static unsigned int 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 size_t malloc_ninfo;
/* Free pages line up here */
static struct pgfree free_list;
/* Abort(), user doesn't handle problems. */
static int malloc_abort = 2;
/* Are we trying to die ? */
static int suicide;
#ifdef MALLOC_STATS
/* dump statistics */
static int malloc_stats;
#endif
/* avoid outputting warnings? */
static int malloc_silent;
/* always realloc ? */
static int malloc_realloc;
/* mprotect free pages PROT_NONE? */
static int malloc_freeprot;
/* use guard pages after allocations? */
static int malloc_guard = 0;
#if defined(__FreeBSD__) || (defined(__OpenBSD__) && defined(MADV_FREE))
/* pass the kernel a hint on free pages ? */
static int malloc_hint;
#endif
/* xmalloc behaviour ? */
static int malloc_xmalloc;
/* zero fill ? */
static int malloc_zero;
/* junk fill ? */
static int malloc_junk;
#ifdef __FreeBSD__
/* utrace ? */
static int malloc_utrace;
struct ut { void *p; size_t s; void *r; };
void utrace(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((void *)0, (size), PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, \
MMAP_FD, (off_t)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);
static void *malloc_bytes(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%lu\n", (u_long)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: ";
struct iovec iov[4];
iov[0].iov_base = __progname;
iov[0].iov_len = strlen(__progname);
iov[1].iov_base = malloc_func;
iov[1].iov_len = strlen(malloc_func);
iov[2].iov_base = q;
iov[2].iov_len = strlen(q);
iov[3].iov_base = p;
iov[3].iov_len = strlen(p);
writev(STDERR_FILENO, iov, 4);
suicide = 1;
#ifdef MALLOC_STATS
if (malloc_stats)
malloc_dump(stderr);
#endif /* MALLOC_STATS */
abort();
}
static void
wrtwarning(char *p)
{
char *q = " warning: ";
struct iovec iov[4];
if (malloc_abort)
wrterror(p);
else if (malloc_silent)
return;
iov[0].iov_base = __progname;
iov[0].iov_len = strlen(__progname);
iov[1].iov_base = malloc_func;
iov[1].iov_len = strlen(malloc_func);
iov[2].iov_base = q;
iov[2].iov_len = strlen(q);
iov[3].iov_base = p;
iov[3].iov_len = strlen(p);
writev(STDERR_FILENO, iov, 4);
}
#ifdef MALLOC_STATS
static void
malloc_exit(void)
{
FILE *fd = fopen("malloc.out", "a");
char *q = "malloc() warning: Couldn't dump stats\n";
if (fd != NULL) {
malloc_dump(fd);
fclose(fd);
} else
write(STDERR_FILENO, q, strlen(q));
}
#endif /* MALLOC_STATS */
/*
* Allocate a number of pages from the OS
*/
static void *
map_pages(size_t pages)
{
caddr_t result, tail;
result = (caddr_t)pageround((u_long)sbrk(0));
pages <<= malloc_pageshift;
if (pages > SIZE_T_MAX - (size_t)result) {
#ifdef MALLOC_EXTRA_SANITY
wrtwarning("(ES): overflow in map_pages fails\n");
#endif /* MALLOC_EXTRA_SANITY */
errno = ENOMEM;
return (NULL);
}
tail = result + pages + malloc_guard;
if (brk(tail) == (char *)-1) {
#ifdef MALLOC_EXTRA_SANITY
wrtwarning("(ES): map_pages fails\n");
#endif /* MALLOC_EXTRA_SANITY */
return (NULL);
}
if (malloc_guard)
mprotect(result + pages, malloc_pagesize, PROT_NONE);
last_index = ptr2index(tail) - 1;
malloc_brk = tail;
if ((last_index+1) >= malloc_ninfo && !extend_pgdir(last_index))
return (NULL);
return (result);
}
/*
* Extend page directory
*/
static int
extend_pgdir(u_long index)
{
struct pginfo **new, **old;
size_t 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 == MAP_FAILED)
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(old, oldlen);
return (1);
}
/*
* Initialize the world
*/
static void
malloc_init(void)
{
char *p, b[64];
int i, j;
int save_errno = errno;
_MALLOC_LOCK_INIT();
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) {
if (issetugid() == 0)
p = getenv("MALLOC_OPTIONS");
else
continue;
} else if (i == 2) {
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;
#ifdef MALLOC_STATS
case 'd': malloc_stats = 0; break;
case 'D': malloc_stats = 1; break;
#endif /* MALLOC_STATS */
case 'f': malloc_freeprot = 0; break;
case 'F': malloc_freeprot = 1; break;
case 'g': malloc_guard = 0; break;
case 'G': malloc_guard = malloc_pagesize; break;
#if defined(__FreeBSD__) || (defined(__OpenBSD__) && defined(MADV_FREE))
case 'h': malloc_hint = 0; break;
case 'H': malloc_hint = 1; break;
#endif /* __FreeBSD__ */
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 'n': malloc_silent = 0; break;
case 'N': malloc_silent = 1; break;
#ifdef __FreeBSD__
case 'u': malloc_utrace = 0; break;
case 'U': malloc_utrace = 1; break;
#endif /* __FreeBSD__ */
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) == -1))
wrtwarning("atexit(2) failed. Will not be able to dump malloc stats on exit\n");
#endif /* MALLOC_STATS */
/* Allocate one page for the page directory */
page_dir = (struct pginfo **) 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 = ((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);
errno = save_errno;
}
/*
* Allocate a number of complete pages
*/
static void *
malloc_pages(size_t size)
{
void *p, *delay_free = NULL;
int i;
struct pgfree *pf;
u_long index;
size = pageround(size) + malloc_guard;
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[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 /* 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;
}
size -= malloc_guard;
#ifdef MALLOC_EXTRA_SANITY
if (p != NULL && page_dir[ptr2index(p)] != MALLOC_FREE)
wrterror("(ES): allocated non-free page on free-list\n");
#endif /* MALLOC_EXTRA_SANITY */
if ((malloc_guard || malloc_freeprot) && p != NULL)
mprotect(p, size, PROT_READ|PROT_WRITE);
size >>= malloc_pageshift;
/* Map new pages */
if (p == NULL)
p = map_pages(size);
if (p != NULL) {
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 == 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, l;
/* Allocate a new bucket */
pp = malloc_pages((size_t)malloc_pagesize);
if (pp == NULL)
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 we are to allocate a memory protected page for the malloc(0)
* case (when bits=0), it must be from a different page than the
* pginfo page.
* --> Treat it like the big chunk alloc, get a second data page.
*/
if (bits != 0 && (1UL<<(bits)) <= l+l) {
bp = (struct pginfo *)pp;
} else {
bp = (struct pginfo *)imalloc(l);
if (bp == NULL) {
ifree(pp);
return (0);
}
}
/* memory protect the page allocated in the malloc(0) case */
if (bits == 0) {
bp->size = 0;
bp->shift = 1;
i = malloc_minsize-1;
while (i >>= 1)
bp->shift++;
bp->total = bp->free = malloc_pagesize >> bp->shift;
bp->page = pp;
k = mprotect(pp, malloc_pagesize, PROT_NONE);
if (k < 0) {
ifree(pp);
ifree(bp);
return (0);
}
} else {
bp->size = (1UL<<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] = ~0UL;
for(; i < k; i++)
bp->bits[i/MALLOC_BITS] |= 1UL<<(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] &= ~(1UL<<(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_long u;
struct pginfo *bp;
int k;
u_long *lp;
/* Don't bother with anything less than this */
/* unless we have a malloc(0) requests */
if (size != 0 && size < malloc_minsize)
size = malloc_minsize;
/* Find the right bucket */
if (size == 0)
j=0;
else {
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++;
}
if (malloc_guard) {
/* Walk to a random position. */
i = arc4random() % bp->free;
while (i > 0) {
u += u;
k++;
if (k >= MALLOC_BITS) {
lp++;
u = 1;
k = 0;
}
#ifdef MALLOC_EXTRA_SANITY
if (lp - bp->bits > (bp->total - 1) / MALLOC_BITS)
wrterror("chunk overflow\n");
#endif /* MALLOC_EXTRA_SANITY */
if (*lp & u)
i--;
}
}
*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 && bp->size != 0)
memset((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 ((size + malloc_pagesize) < size) { /* Check for overflow */
result = NULL;
errno = ENOMEM;
}
else if (size <= malloc_maxsize)
result = malloc_bytes(size);
else
result = malloc_pages(size);
if (malloc_abort == 1 && 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;
u_long osize, index;
struct pginfo **mp;
int i;
if (suicide)
abort();
if (!malloc_started) {
wrtwarning("malloc() has never been called\n");
return (NULL);
}
index = ptr2index(ptr);
if (index < malloc_pageshift) {
wrtwarning("junk pointer, too low to make sense\n");
return (NULL);
}
if (index > last_index) {
wrtwarning("junk pointer, too high to make sense\n");
return (NULL);
}
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 (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((char *)ptr + size, SOME_JUNK, osize-size);
return (ptr); /* ..don't do anything else. */
}
} else if (*mp >= MALLOC_MAGIC) { /* Chunk allocation */
/* Check the pointer for sane values */
if ((u_long)ptr & ((1UL<<((*mp)->shift))-1)) {
wrtwarning("modified (chunk-) pointer\n");
return (NULL);
}
/* 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] & (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((char *)ptr + size, SOME_JUNK, osize-size);
return (ptr); /* ..don't do anything else. */
}
} 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 */
/* Don't move from/to 0 sized region !!! */
if (osize != 0 && size != 0) {
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, u_long index, struct pginfo *info)
{
u_long i, l;
struct pgfree *pf, *pt=NULL;
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 defined(__FreeBSD__) || (defined(__OpenBSD__) && defined(MADV_FREE))
if (malloc_hint)
madvise(ptr, l, MADV_FREE);
#endif
if (malloc_guard) {
page_dir[index + i] = MALLOC_FREE;
l += malloc_guard;
}
tail = (char *)ptr+l;
if (malloc_freeprot)
mprotect(ptr, tail - ptr, PROT_NONE);
/* 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. */
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(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);
for(i=index;i <= last_index;)
page_dir[i++] = MALLOC_NOT_MINE;
last_index = index - 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.
*/
/* ARGSUSED */
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 & ((1UL<<(info->shift))-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 && info->size != 0)
memset(ptr, SOME_JUNK, info->size);
info->bits[i/MALLOC_BITS] |= 1UL<<(i%MALLOC_BITS);
info->free++;
if (info->size != 0)
mp = page_dir + info->shift;
else
mp = page_dir;
if (info->free == 1) {
/* Page became non-full */
/* 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[ptr2index(info->page)] = MALLOC_FIRST;
/* If the page was mprotected, unprotect it before releasing it */
if (info->size == 0) {
mprotect(info->page, malloc_pagesize, PROT_READ|PROT_WRITE);
/* Do we have to care if mprotect succeeds here ? */
}
vp = info->page; /* Order is important ! */
if(vp != (void*)info)
ifree(info);
ifree(vp);
}
static void
ifree(void *ptr)
{
struct pginfo *info;
u_long index;
/* This is legal */
if (ptr == NULL)
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;
}
static int malloc_active;
/*
* Common function for handling recursion. Only
* print the error message once, to avoid making the problem
* potentially worse.
*/
static void
malloc_recurse(void)
{
static int noprint;
if (noprint == 0)
wrtwarning("recursive call\n");
noprint = 1;
malloc_active--;
_MALLOC_UNLOCK();
errno = EDEADLK;
}
/*
* These are the public exported interface routines.
*/
void *
malloc(size_t size)
{
void *r;
_MALLOC_LOCK();
malloc_func = " in malloc():";
if (malloc_active++) {
malloc_recurse();
return (NULL);
}
r = imalloc(size);
UTRACE(0, size, r);
malloc_active--;
_MALLOC_UNLOCK();
if (malloc_xmalloc && r == NULL)
wrterror("out of memory\n");
return (r);
}
void
free(void *ptr)
{
_MALLOC_LOCK();
malloc_func = " in free():";
if (malloc_active++) {
malloc_recurse();
return;
}
ifree(ptr);
UTRACE(ptr, 0, 0);
malloc_active--;
_MALLOC_UNLOCK();
return;
}
void *
realloc(void *ptr, size_t size)
{
void *r;
_MALLOC_LOCK();
malloc_func = " in realloc():";
if (malloc_active++) {
malloc_recurse();
return (NULL);
}
if (ptr == NULL) {
r = imalloc(size);
} else {
r = irealloc(ptr, size);
}
UTRACE(ptr, size, r);
malloc_active--;
_MALLOC_UNLOCK();
if (malloc_xmalloc && r == NULL)
wrterror("out of memory\n");
return (r);
}