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e22c2d3
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eliminate OOB array hacks in malloc
author
Rich Felker
<dalias@aerifal.cx>
Sun, 26 Jun 2011 20:12:43 +0000
(16:12 -0400)
committer
Rich Felker
<dalias@aerifal.cx>
Sun, 26 Jun 2011 20:12:43 +0000
(16:12 -0400)
src/malloc/malloc.c
patch
|
blob
|
history
diff --git
a/src/malloc/malloc.c
b/src/malloc/malloc.c
index
207b6ef
..
db4287e
100644
(file)
--- a/
src/malloc/malloc.c
+++ b/
src/malloc/malloc.c
@@
-16,9
+16,8
@@
void *__mremap(void *, size_t, size_t, int, ...);
int __madvise(void *, size_t, int);
struct chunk {
int __madvise(void *, size_t, int);
struct chunk {
- size_t data[1];
- struct chunk *next;
- struct chunk *prev;
+ size_t psize, csize;
+ struct chunk *next, *prev;
};
struct bin {
};
struct bin {
@@
-44,19
+43,19
@@
static struct {
#define DONTCARE 16
#define RECLAIM 163840
#define DONTCARE 16
#define RECLAIM 163840
-#define CHUNK_SIZE(c) ((c)->
data[0]
& SIZE_MASK)
-#define CHUNK_PSIZE(c) ((c)->
data[-1]
& SIZE_MASK)
+#define CHUNK_SIZE(c) ((c)->
csize
& SIZE_MASK)
+#define CHUNK_PSIZE(c) ((c)->
psize
& SIZE_MASK)
#define PREV_CHUNK(c) ((struct chunk *)((char *)(c) - CHUNK_PSIZE(c)))
#define NEXT_CHUNK(c) ((struct chunk *)((char *)(c) + CHUNK_SIZE(c)))
#define PREV_CHUNK(c) ((struct chunk *)((char *)(c) - CHUNK_PSIZE(c)))
#define NEXT_CHUNK(c) ((struct chunk *)((char *)(c) + CHUNK_SIZE(c)))
-#define MEM_TO_CHUNK(p) (struct chunk *)((
size_t *)p - 1
)
-#define CHUNK_TO_MEM(c) (void *)((c
)->data+1
)
+#define MEM_TO_CHUNK(p) (struct chunk *)((
char *)(p) - OVERHEAD
)
+#define CHUNK_TO_MEM(c) (void *)((c
har *)(c) + OVERHEAD
)
#define BIN_TO_CHUNK(i) (MEM_TO_CHUNK(&mal.bins[i].head))
#define C_INUSE ((size_t)1)
#define C_FLAGS ((size_t)3)
#define C_SIZE SIZE_MASK
#define BIN_TO_CHUNK(i) (MEM_TO_CHUNK(&mal.bins[i].head))
#define C_INUSE ((size_t)1)
#define C_FLAGS ((size_t)3)
#define C_SIZE SIZE_MASK
-#define IS_MMAPPED(c) !((c)->
data[0]
& (C_INUSE))
+#define IS_MMAPPED(c) !((c)->
csize
& (C_INUSE))
/* Synchronization tools */
/* Synchronization tools */
@@
-138,8
+137,8
@@
void __dump_heap(int x)
for (c = (void *)mal.heap; CHUNK_SIZE(c); c = NEXT_CHUNK(c))
fprintf(stderr, "base %p size %zu (%d) flags %d/%d\n",
c, CHUNK_SIZE(c), bin_index(CHUNK_SIZE(c)),
for (c = (void *)mal.heap; CHUNK_SIZE(c); c = NEXT_CHUNK(c))
fprintf(stderr, "base %p size %zu (%d) flags %d/%d\n",
c, CHUNK_SIZE(c), bin_index(CHUNK_SIZE(c)),
- c->
data[0]
& 15,
- NEXT_CHUNK(c)->
data[-1]
& 15);
+ c->
csize
& 15,
+ NEXT_CHUNK(c)->
psize
& 15);
for (i=0; i<64; i++) {
if (mal.bins[i].head != BIN_TO_CHUNK(i) && mal.bins[i].head) {
fprintf(stderr, "bin %d: %p\n", i, mal.bins[i].head);
for (i=0; i<64; i++) {
if (mal.bins[i].head != BIN_TO_CHUNK(i) && mal.bins[i].head) {
fprintf(stderr, "bin %d: %p\n", i, mal.bins[i].head);
@@
-165,11
+164,11
@@
static struct chunk *expand_heap(size_t n)
if (__brk(new) != new) goto fail;
w = MEM_TO_CHUNK(new);
if (__brk(new) != new) goto fail;
w = MEM_TO_CHUNK(new);
- w->
data[-1]
= n | C_INUSE;
- w->
data[0]
= 0 | C_INUSE;
+ w->
psize
= n | C_INUSE;
+ w->
csize
= 0 | C_INUSE;
w = MEM_TO_CHUNK(mal.brk);
w = MEM_TO_CHUNK(mal.brk);
- w->
data[0]
= n | C_INUSE;
+ w->
csize
= n | C_INUSE;
mal.brk = new;
unlock(mal.brk_lock);
mal.brk = new;
unlock(mal.brk_lock);
@@
-206,7
+205,7
@@
static int init_malloc(size_t n)
}
mal.heap = (void *)c;
}
mal.heap = (void *)c;
- c->
data[-1]
= 0 | C_INUSE;
+ c->
psize
= 0 | C_INUSE;
free(CHUNK_TO_MEM(c));
a_store(&init, 2);
free(CHUNK_TO_MEM(c));
a_store(&init, 2);
@@
-236,18
+235,18
@@
static void unbin(struct chunk *c, int i)
a_and_64(&mal.binmap, ~(1ULL<<i));
c->prev->next = c->next;
c->next->prev = c->prev;
a_and_64(&mal.binmap, ~(1ULL<<i));
c->prev->next = c->next;
c->next->prev = c->prev;
- c->
data[0]
|= C_INUSE;
- NEXT_CHUNK(c)->
data[-1]
|= C_INUSE;
+ c->
csize
|= C_INUSE;
+ NEXT_CHUNK(c)->
psize
|= C_INUSE;
}
static int alloc_fwd(struct chunk *c)
{
int i;
size_t k;
}
static int alloc_fwd(struct chunk *c)
{
int i;
size_t k;
- while (!((k=c->
data[0]
) & C_INUSE)) {
+ while (!((k=c->
csize
) & C_INUSE)) {
i = bin_index(k);
lock_bin(i);
i = bin_index(k);
lock_bin(i);
- if (c->
data[0]
== k) {
+ if (c->
csize
== k) {
unbin(c, i);
unlock_bin(i);
return 1;
unbin(c, i);
unlock_bin(i);
return 1;
@@
-261,10
+260,10
@@
static int alloc_rev(struct chunk *c)
{
int i;
size_t k;
{
int i;
size_t k;
- while (!((k=c->
data[-1]
) & C_INUSE)) {
+ while (!((k=c->
psize
) & C_INUSE)) {
i = bin_index(k);
lock_bin(i);
i = bin_index(k);
lock_bin(i);
- if (c->
data[-1]
== k) {
+ if (c->
psize
== k) {
unbin(PREV_CHUNK(c), i);
unlock_bin(i);
return 1;
unbin(PREV_CHUNK(c), i);
unlock_bin(i);
return 1;
@@
-301,10
+300,10
@@
static int pretrim(struct chunk *self, size_t n, int i, int j)
split->next = self->next;
split->prev->next = split;
split->next->prev = split;
split->next = self->next;
split->prev->next = split;
split->next->prev = split;
- split->
data[-1]
= n | C_INUSE;
- split->
data[0]
= n1-n;
- next->
data[-1]
= n1-n;
- self->
data[0]
= n | C_INUSE;
+ split->
psize
= n | C_INUSE;
+ split->
csize
= n1-n;
+ next->
psize
= n1-n;
+ self->
csize
= n | C_INUSE;
return 1;
}
return 1;
}
@@
-318,10
+317,10
@@
static void trim(struct chunk *self, size_t n)
next = NEXT_CHUNK(self);
split = (void *)((char *)self + n);
next = NEXT_CHUNK(self);
split = (void *)((char *)self + n);
- split->
data[-1]
= n | C_INUSE;
- split->
data[0]
= n1-n | C_INUSE;
- next->
data[-1]
= n1-n | C_INUSE;
- self->
data[0]
= n | C_INUSE;
+ split->
psize
= n | C_INUSE;
+ split->
csize
= n1-n | C_INUSE;
+ next->
psize
= n1-n | C_INUSE;
+ self->
csize
= n | C_INUSE;
free(CHUNK_TO_MEM(split));
}
free(CHUNK_TO_MEM(split));
}
@@
-338,9
+337,9
@@
void *malloc(size_t n)
char *base = __mmap(0, len, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
if (base == (void *)-1) return 0;
char *base = __mmap(0, len, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
if (base == (void *)-1) return 0;
- c = (void *)(base + SIZE_ALIGN -
sizeof(size_t)
);
- c->
data[0] = len - (SIZE_ALIGN - sizeof(size_t)
);
- c->
data[-1] = SIZE_ALIGN - sizeof(size_t)
;
+ c = (void *)(base + SIZE_ALIGN -
OVERHEAD
);
+ c->
csize = len - (SIZE_ALIGN - OVERHEAD
);
+ c->
psize = SIZE_ALIGN - OVERHEAD
;
return CHUNK_TO_MEM(c);
}
return CHUNK_TO_MEM(c);
}
@@
-354,15
+353,15
@@
void *malloc(size_t n)
if (alloc_rev(c)) {
struct chunk *x = c;
c = PREV_CHUNK(c);
if (alloc_rev(c)) {
struct chunk *x = c;
c = PREV_CHUNK(c);
- NEXT_CHUNK(x)->
data[-1] = c->data[0]
=
- x->
data[0]
+ CHUNK_SIZE(c);
+ NEXT_CHUNK(x)->
psize = c->csize
=
+ x->
csize
+ CHUNK_SIZE(c);
}
break;
}
j = first_set(mask);
lock_bin(j);
c = mal.bins[j].head;
}
break;
}
j = first_set(mask);
lock_bin(j);
c = mal.bins[j].head;
- if (c != BIN_TO_CHUNK(j) && j == bin_index(c->
data[0]
)) {
+ if (c != BIN_TO_CHUNK(j) && j == bin_index(c->
csize
)) {
if (!pretrim(c, n, i, j)) unbin(c, j);
unlock_bin(j);
break;
if (!pretrim(c, n, i, j)) unbin(c, j);
unlock_bin(j);
break;
@@
-390,7
+389,7
@@
void *realloc(void *p, size_t n)
n1 = n0 = CHUNK_SIZE(self);
if (IS_MMAPPED(self)) {
n1 = n0 = CHUNK_SIZE(self);
if (IS_MMAPPED(self)) {
- size_t extra = self->
data[-1]
;
+ size_t extra = self->
psize
;
char *base = (char *)self - extra;
size_t oldlen = n0 + extra;
size_t newlen = n + extra;
char *base = (char *)self - extra;
size_t oldlen = n0 + extra;
size_t newlen = n + extra;
@@
-407,7
+406,7
@@
void *realloc(void *p, size_t n)
if (base == (void *)-1)
return newlen < oldlen ? p : 0;
self = (void *)(base + extra);
if (base == (void *)-1)
return newlen < oldlen ? p : 0;
self = (void *)(base + extra);
- self->
data[0]
= newlen - extra;
+ self->
csize
= newlen - extra;
return CHUNK_TO_MEM(self);
}
return CHUNK_TO_MEM(self);
}
@@
-425,8
+424,8
@@
void *realloc(void *p, size_t n)
self = PREV_CHUNK(self);
n1 += CHUNK_SIZE(self);
}
self = PREV_CHUNK(self);
n1 += CHUNK_SIZE(self);
}
- self->
data[0]
= n1 | C_INUSE;
- next->
data[-1]
= n1 | C_INUSE;
+ self->
csize
= n1 | C_INUSE;
+ next->
psize
= n1 | C_INUSE;
/* If we got enough space, split off the excess and return */
if (n <= n1) {
/* If we got enough space, split off the excess and return */
if (n <= n1) {
@@
-454,7
+453,7
@@
void free(void *p)
if (!p) return;
if (IS_MMAPPED(self)) {
if (!p) return;
if (IS_MMAPPED(self)) {
- size_t extra = self->
data[-1]
;
+ size_t extra = self->
psize
;
char *base = (char *)self - extra;
size_t len = CHUNK_SIZE(self) + extra;
/* Crash on double free */
char *base = (char *)self - extra;
size_t len = CHUNK_SIZE(self) + extra;
/* Crash on double free */
@@
-468,7
+467,7
@@
void free(void *p)
for (;;) {
/* Replace middle of large chunks with fresh zero pages */
for (;;) {
/* Replace middle of large chunks with fresh zero pages */
- if (reclaim && (self->
data[-1] & next->data[0]
& C_INUSE)) {
+ if (reclaim && (self->
psize & next->csize
& C_INUSE)) {
uintptr_t a = (uintptr_t)self + SIZE_ALIGN+PAGE_SIZE-1 & -PAGE_SIZE;
uintptr_t b = (uintptr_t)next - SIZE_ALIGN & -PAGE_SIZE;
#if 1
uintptr_t a = (uintptr_t)self + SIZE_ALIGN+PAGE_SIZE-1 & -PAGE_SIZE;
uintptr_t b = (uintptr_t)next - SIZE_ALIGN & -PAGE_SIZE;
#if 1
@@
-479,13
+478,13
@@
void free(void *p)
#endif
}
#endif
}
- if (self->
data[-1] & next->data[0]
& C_INUSE) {
- self->
data[0]
= final_size | C_INUSE;
- next->
data[-1]
= final_size | C_INUSE;
+ if (self->
psize & next->csize
& C_INUSE) {
+ self->
csize
= final_size | C_INUSE;
+ next->
psize
= final_size | C_INUSE;
i = bin_index(final_size);
lock_bin(i);
lock(mal.free_lock);
i = bin_index(final_size);
lock_bin(i);
lock(mal.free_lock);
- if (self->
data[-1] & next->data[0]
& C_INUSE)
+ if (self->
psize & next->csize
& C_INUSE)
break;
unlock(mal.free_lock);
unlock_bin(i);
break;
unlock(mal.free_lock);
unlock_bin(i);
@@
-508,8
+507,8
@@
void free(void *p)
}
}
}
}
- self->
data[0]
= final_size;
- next->
data[-1]
= final_size;
+ self->
csize
= final_size;
+ next->
psize
= final_size;
unlock(mal.free_lock);
self->next = BIN_TO_CHUNK(i);
unlock(mal.free_lock);
self->next = BIN_TO_CHUNK(i);