mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-07-26 20:40:28 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Improve memory safety

Browse source 
This commit makes numerous refinements to cosmopolitan memory handling.

The default stack size has been reduced from 2mb to 128kb. A new macro
is now provided so you can easily reconfigure the stack size to be any
value you want. Work around the breaking change by adding to your main:

    STATIC_STACK_SIZE(0x00200000);  // 2mb stack

If you're not sure how much stack you need, then you can use:

    STATIC_YOINK("stack_usage_logging");

After which you can `sort -nr o/$MODE/stack.log`. Based on the unit test
suite, nothing in the Cosmopolitan repository (except for Python) needs
a stack size greater than 30kb. There are also new macros for detecting
the size and address of the stack at runtime, e.g. GetStackAddr(). We
also now support sigaltstack() so if you want to see nice looking crash
reports whenever a stack overflow happens, you can put this in main():

    ShowCrashReports();

Under `make MODE=dbg` and `make MODE=asan` the unit testing framework
will now automatically print backtraces of memory allocations when
things like memory leaks happen. Bugs are now fixed in ASAN global
variable overrun detection. The memtrack and asan runtimes also handle
edge cases now. The new tools helped to identify a few memory leaks,
which are fixed by this change.

This change should fix an issue reported in #288 with ARG_MAX limits.
Fixing this doubled the performance of MKDEPS.COM and AR.COM yet again.
This commit is contained in:
Justine Tunney 2021-10-13 17:27:13 -07:00
parent a0b39f886c
commit 226aaf3547
317 changed files with 6474 additions and 3993 deletions
Download patch file Download diff file Expand all files Collapse all files

312
libc/mem/arena.c
View file

@ -22,37 +22,39 @@
#include "libc/calls/calls.h"
#include "libc/dce.h"
#include "libc/limits.h"
#include "libc/log/libfatal.internal.h"
#include "libc/log/log.h"
#include "libc/macros.internal.h"
#include "libc/mem/arena.h"
#include "libc/mem/hook/hook.internal.h"
#include "libc/nexgen32e/bsf.h"
#include "libc/nexgen32e/bsr.h"
#include "libc/runtime/memtrack.internal.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/errfuns.h"
#define BASE ((char *)0x30000000)
#define LIMIT ((char *)0x50000000)
#define BASE 0x50000000
#define SIZE 0x2ffe0000
#define P(i) ((void *)(intptr_t)(i))
#define EXCHANGE(HOOK, SLOT) \
__arena_hook((intptr_t *)weaken(HOOK), (intptr_t *)(&(SLOT)))
static struct Arena {
bool once;
uint8_t depth;
unsigned size;
unsigned offset[16];
size_t size;
size_t depth;
size_t offset[16];
void (*free)(void *);
void *(*malloc)(size_t);
void *(*calloc)(size_t, size_t);
void *(*memalign)(size_t, size_t);
void *(*realloc)(void *, size_t);
void *(*realloc_in_place)(void *, size_t);
void *(*valloc)(size_t);
void *(*pvalloc)(size_t);
int (*malloc_trim)(size_t);
size_t (*malloc_usable_size)(const void *);
size_t (*bulk_free)(void *[], size_t);
int (*malloc_trim)(size_t);
} __arena;
static wontreturn void __arena_die(void) {
@ -61,103 +63,202 @@ static wontreturn void __arena_die(void) {
}
static wontreturn void __arena_not_implemented(void) {
__printf("not implemented");
assert(!"not implemented");
__arena_die();
}
static void __arena_free(void *p) {
if (!p) return;
forceinline void __arena_check(void) {
assert(__arena.depth);
assert((intptr_t)BASE + __arena.offset[__arena.depth - 1] <= (intptr_t)p &&
(intptr_t)p < (intptr_t)BASE + __arena.offset[__arena.depth]);
}
forceinline void __arena_check_pointer(void *p) {
assert(BASE + __arena.offset[__arena.depth - 1] <= (uintptr_t)p &&
(uintptr_t)p < BASE + __arena.offset[__arena.depth]);
}
forceinline bool __arena_is_arena_pointer(void *p) {
return BASE <= (uintptr_t)p && (uintptr_t)p < BASE + SIZE;
}
forceinline size_t __arena_get_size(void *p) {
return *(const size_t *)((const char *)p - sizeof(size_t));
}
static void __arena_free(void *p) {
__arena_check();
if (p) {
__arena_check_pointer(p);
if (!(BASE <= (uintptr_t)p && (uintptr_t)p < BASE + SIZE)) {
__arena.free(p);
}
}
}
static size_t __arena_bulk_free(void *p[], size_t n) {
size_t i;
for (i = 0; i < n; ++i) {
if (p[i]) __arena_free(p[i]);
__arena_free(p[i]);
p[i] = 0;
}
bzero(p, n * sizeof(void *));
return 0;
}
static noinline bool __arena_grow(size_t offset, size_t request) {
size_t greed;
greed = __arena.size + 1;
do {
greed += greed >> 1;
greed = ROUNDUP(greed, FRAMESIZE);
} while (greed < offset + request);
if (greed <= SIZE) {
if (mmap(P(BASE + __arena.size), greed - __arena.size,
PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED,
-1, 0) != MAP_FAILED) {
__arena.size = greed;
return true;
}
} else {
enomem();
}
if (weaken(__oom_hook)) {
weaken(__oom_hook)(request);
}
return false;
}
static void *__arena_alloc(size_t a, size_t n) {
size_t o;
if (!n) n = 1;
o = ROUNDUP(__arena.offset[__arena.depth] + sizeof(size_t), a);
if (o + n >= n) {
if (n <= sizeof(size_t)) {
n = sizeof(size_t);
} else {
n = ROUNDUP(n, sizeof(size_t));
}
if (o + n <= SIZE) {
if (UNLIKELY(o + n > __arena.size)) {
if (!__arena_grow(o, n)) return 0;
}
__arena.offset[__arena.depth] = o + n;
*(size_t *)(BASE + o - sizeof(size_t)) = n;
return (void *)(BASE + o);
}
}
enomem();
return 0;
}
static void *__arena_malloc(size_t n) {
char *ptr;
size_t need, greed;
assert(__arena.depth);
if (!n) n = 1;
if (n < LIMIT - BASE) {
need = __arena.offset[__arena.depth] + n;
need = ROUNDUP(need, __BIGGEST_ALIGNMENT__);
if (UNLIKELY(need > __arena.size)) {
greed = __arena.size + 1;
do {
greed += greed >> 1;
greed = ROUNDUP(greed, FRAMESIZE);
} while (need > greed);
if (greed < LIMIT - BASE &&
mmap(BASE + __arena.size, greed - __arena.size,
PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED,
-1, 0) != MAP_FAILED) {
__arena.size = greed;
__arena_check();
return __arena_alloc(16, n);
}
static void *__arena_calloc(size_t n, size_t z) {
__arena_check();
if (__builtin_mul_overflow(n, z, &n)) n = -1;
return __arena_alloc(16, n);
}
static void *__arena_memalign(size_t a, size_t n) {
__arena_check();
if (a <= sizeof(size_t)) {
return __arena_alloc(8, n);
} else {
return __arena_alloc(2ul << bsrl(a - 1), n);
}
}
static size_t __arena_malloc_usable_size(const void *p) {
__arena_check();
__arena_check_pointer(p);
if (__arena_is_arena_pointer(p)) {
return __arena_get_size(p);
} else {
return __arena.malloc_usable_size(p);
}
}
static void *__arena_realloc(void *p, size_t n) {
char *q;
size_t m, o, z;
__arena_check();
if (p) {
__arena_check_pointer(p);
if (__arena_is_arena_pointer(p)) {
if (n) {
if ((m = __arena_get_size(p)) >= n) {
return p;
} else if (n <= SIZE) {
z = 2ul << bsrl(n - 1);
if (__arena.offset[__arena.depth] - m == (o = (intptr_t)p - BASE)) {
if (UNLIKELY(o + z > __arena.size)) {
if (o + z <= SIZE) {
if (!__arena_grow(o, z)) {
return 0;
}
} else {
enomem();
return 0;
}
}
__arena.offset[__arena.depth] = o + z;
*(size_t *)((char *)p - sizeof(size_t)) = z;
return p;
} else if ((q = __arena_alloc(1ul << bsfl((intptr_t)p), z))) {
memmove(q, p, m);
return q;
} else {
return 0;
}
} else {
enomem();
return 0;
}
} else {
return 0;
}
} else {
return __arena.realloc(p, n);
}
} else {
if (n <= 16) {
n = 16;
} else {
n = 2ul << bsrl(n - 1);
}
return __arena_alloc(16, n);
}
}
static void *__arena_realloc_in_place(void *p, size_t n) {
char *q;
size_t m, z;
__arena_check();
if (p) {
__arena_check_pointer(p);
if (__arena_is_arena_pointer(p)) {
if (n) {
if ((m = __arena_get_size(p)) >= n) {
return p;
} else {
return 0;
}
} else {
return 0;
}
} else {
return __arena.realloc_in_place(p, n);
}
ptr = BASE + __arena.offset[__arena.depth];
__arena.offset[__arena.depth] = need;
return ptr;
} else {
return 0;
}
}
static void *__arena_calloc(size_t n, size_t z) {
if (__builtin_mul_overflow(n, z, &n)) n = -1;
return __arena_malloc(n);
}
static void *__arena_memalign(size_t a, size_t n) {
if (a <= __BIGGEST_ALIGNMENT__) {
return __arena_malloc(n);
} else {
__arena_not_implemented();
}
}
static void *__arena_realloc(void *p, size_t n) {
if (p) {
if (n) {
__arena_not_implemented();
} else {
__arena_free(p);
return 0;
}
} else {
return __arena_malloc(n);
}
}
static int __arena_malloc_trim(size_t n) {
return 0;
}
static void *__arena_realloc_in_place(void *p, size_t n) {
__arena_not_implemented();
}
static void *__arena_valloc(size_t n) {
__arena_not_implemented();
}
static void *__arena_pvalloc(size_t n) {
__arena_not_implemented();
}
static size_t __arena_malloc_usable_size(const void *p) {
__arena_not_implemented();
}
static void __arena_hook(intptr_t *h, intptr_t *f) {
intptr_t t;
if (h) {
@ -169,42 +270,32 @@ static void __arena_hook(intptr_t *h, intptr_t *f) {
static void __arena_install(void) {
EXCHANGE(hook_free, __arena.free);
EXCHANGE(hook_realloc, __arena.realloc);
EXCHANGE(hook_realloc, __arena.realloc);
EXCHANGE(hook_malloc, __arena.malloc);
EXCHANGE(hook_calloc, __arena.calloc);
EXCHANGE(hook_realloc, __arena.realloc);
EXCHANGE(hook_memalign, __arena.memalign);
EXCHANGE(hook_realloc_in_place, __arena.realloc_in_place);
EXCHANGE(hook_valloc, __arena.valloc);
EXCHANGE(hook_pvalloc, __arena.pvalloc);
EXCHANGE(hook_malloc_trim, __arena.malloc_trim);
EXCHANGE(hook_malloc_usable_size, __arena.malloc_usable_size);
EXCHANGE(hook_bulk_free, __arena.bulk_free);
EXCHANGE(hook_malloc_trim, __arena.malloc_trim);
EXCHANGE(hook_realloc_in_place, __arena.realloc_in_place);
EXCHANGE(hook_malloc_usable_size, __arena.malloc_usable_size);
}
static void __arena_destroy(void) {
if (__arena.depth) {
__arena_install();
}
if (__arena.size) {
munmap(BASE, __arena.size);
}
if (__arena.depth) __arena_install();
if (__arena.size) munmap(P(BASE), __arena.size);
bzero(&__arena, sizeof(__arena));
}
static void __arena_init(void) {
__arena.free = __arena_free;
__arena.realloc = __arena_realloc;
__arena.realloc = __arena_realloc;
__arena.malloc = __arena_malloc;
__arena.calloc = __arena_calloc;
__arena.realloc = __arena_realloc;
__arena.memalign = __arena_memalign;
__arena.realloc_in_place = __arena_realloc_in_place;
__arena.valloc = __arena_valloc;
__arena.pvalloc = __arena_pvalloc;
__arena.malloc_trim = __arena_malloc_trim;
__arena.malloc_usable_size = __arena_malloc_usable_size;
__arena.bulk_free = __arena_bulk_free;
__arena.malloc_trim = __arena_malloc_trim;
__arena.realloc_in_place = __arena_realloc_in_place;
__arena.malloc_usable_size = __arena_malloc_usable_size;
atexit(__arena_destroy);
}
@ -215,24 +306,27 @@ void __arena_push(void) {
}
if (!__arena.depth) {
__arena_install();
} else if (__arena.depth == ARRAYLEN(__arena.offset) - 1) {
__printf("too many arenas");
__arena_die();
} else {
assert(__arena.depth < ARRAYLEN(__arena.offset) - 1);
}
__arena.offset[__arena.depth + 1] = __arena.offset[__arena.depth];
++__arena.depth;
}
void __arena_pop(void) {
unsigned greed;
assert(__arena.depth);
bzero(BASE + __arena.offset[__arena.depth - 1],
__arena.offset[__arena.depth] - __arena.offset[__arena.depth - 1]);
size_t a, b, greed;
__arena_check();
if (!--__arena.depth) __arena_install();
greed = __arena.offset[__arena.depth];
a = __arena.offset[__arena.depth];
b = __arena.offset[__arena.depth + 1];
greed = a;
greed += FRAMESIZE;
greed <<= 1;
if (__arena.size > greed) {
munmap(BASE + greed, __arena.size - greed);
munmap(P(BASE + greed), __arena.size - greed);
__arena.size = greed;
b = MIN(b, greed);
a = MIN(b, a);
}
bzero(P(BASE + a), b - a);
}