X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fmalloc%2Fmalloc.c;h=b90636cc67fda06dac201526d43a42f5e040971c;hb=6fef8cafbd0f6f185897bc87feb1ff66e2e204e1;hp=abf3e8fa268ad8a7244e9a1b938bd3f744fcf0d1;hpb=1c8bead345eca58ddc5177a121142b527937adee;p=musl diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c index abf3e8fa..b90636cc 100644 --- a/src/malloc/malloc.c +++ b/src/malloc/malloc.c @@ -9,7 +9,10 @@ #include "atomic.h" #include "pthread_impl.h" -uintptr_t __brk(uintptr_t); +#if defined(__GNUC__) && defined(__PIC__) +#define inline inline __attribute__((always_inline)) +#endif + void *__mmap(void *, size_t, int, int, int, off_t); int __munmap(void *, size_t); void *__mremap(void *, size_t, size_t, int, ...); @@ -21,18 +24,15 @@ struct chunk { }; struct bin { - int lock[2]; + volatile int lock[2]; struct chunk *head; struct chunk *tail; }; static struct { - uintptr_t brk; - size_t *heap; - uint64_t binmap; + volatile uint64_t binmap; struct bin bins[64]; - int brk_lock[2]; - int free_lock[2]; + volatile int free_lock[2]; } mal; @@ -43,8 +43,8 @@ static struct { #define DONTCARE 16 #define RECLAIM 163840 -#define CHUNK_SIZE(c) ((c)->csize & SIZE_MASK) -#define CHUNK_PSIZE(c) ((c)->psize & SIZE_MASK) +#define CHUNK_SIZE(c) ((c)->csize & -2) +#define CHUNK_PSIZE(c) ((c)->psize & -2) #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 *)((char *)(p) - OVERHEAD) @@ -52,38 +52,35 @@ static struct { #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)->csize & (C_INUSE)) /* Synchronization tools */ -static void lock(volatile int *lk) +static inline void lock(volatile int *lk) { - if (!libc.threads_minus_1) return; - while(a_swap(lk, 1)) __wait(lk, lk+1, 1, 1); + if (libc.threads_minus_1) + while(a_swap(lk, 1)) __wait(lk, lk+1, 1, 1); } -static void unlock(volatile int *lk) +static inline void unlock(volatile int *lk) { - if (!libc.threads_minus_1) return; - a_store(lk, 0); - if (lk[1]) __wake(lk, 1, 1); + if (lk[0]) { + a_store(lk, 0); + if (lk[1]) __wake(lk, 1, 1); + } } -static void lock_bin(int i) +static inline void lock_bin(int i) { - if (libc.threads_minus_1) - lock(mal.bins[i].lock); + lock(mal.bins[i].lock); if (!mal.bins[i].head) mal.bins[i].head = mal.bins[i].tail = BIN_TO_CHUNK(i); } -static void unlock_bin(int i) +static inline void unlock_bin(int i) { - if (!libc.threads_minus_1) return; unlock(mal.bins[i].lock); } @@ -150,67 +147,52 @@ void __dump_heap(int x) } #endif +void *__expand_heap(size_t *); + static struct chunk *expand_heap(size_t n) { + static int heap_lock[2]; + static void *end; + void *p; struct chunk *w; - uintptr_t new; - - lock(mal.brk_lock); - - if (n > SIZE_MAX - mal.brk - 2*PAGE_SIZE) goto fail; - new = mal.brk + n + SIZE_ALIGN + PAGE_SIZE - 1 & -PAGE_SIZE; - n = new - mal.brk; - - if (__brk(new) != new) goto fail; - - w = MEM_TO_CHUNK(new); - w->psize = n | C_INUSE; - w->csize = 0 | C_INUSE; - w = MEM_TO_CHUNK(mal.brk); - w->csize = n | C_INUSE; - mal.brk = new; - - unlock(mal.brk_lock); - - return w; -fail: - unlock(mal.brk_lock); - return 0; -} - -static int init_malloc(size_t n) -{ - static int init, waiters; - int state; - struct chunk *c; + /* The argument n already accounts for the caller's chunk + * overhead needs, but if the heap can't be extended in-place, + * we need room for an extra zero-sized sentinel chunk. */ + n += SIZE_ALIGN; - if (init == 2) return 0; + lock(heap_lock); - while ((state=a_swap(&init, 1)) == 1) - __wait(&init, &waiters, 1, 1); - if (state) { - a_store(&init, 2); + p = __expand_heap(&n); + if (!p) { + unlock(heap_lock); return 0; } - mal.brk = __brk(0) + 2*SIZE_ALIGN-1 & -SIZE_ALIGN; + /* If not just expanding existing space, we need to make a + * new sentinel chunk below the allocated space. */ + if (p != end) { + /* Valid/safe because of the prologue increment. */ + n -= SIZE_ALIGN; + p = (char *)p + SIZE_ALIGN; + w = MEM_TO_CHUNK(p); + w->psize = 0 | C_INUSE; + } - c = expand_heap(n); + /* Record new heap end and fill in footer. */ + end = (char *)p + n; + w = MEM_TO_CHUNK(end); + w->psize = n | C_INUSE; + w->csize = 0 | C_INUSE; - if (!c) { - a_store(&init, 0); - if (waiters) __wake(&init, 1, 1); - return -1; - } + /* Fill in header, which may be new or may be replacing a + * zero-size sentinel header at the old end-of-heap. */ + w = MEM_TO_CHUNK(p); + w->csize = n | C_INUSE; - mal.heap = (void *)c; - c->psize = 0 | C_INUSE; - free(CHUNK_TO_MEM(c)); + unlock(heap_lock); - a_store(&init, 2); - if (waiters) __wake(&init, -1, 1); - return 1; + return w; } static int adjust_size(size_t *n) @@ -347,7 +329,6 @@ void *malloc(size_t n) for (;;) { uint64_t mask = mal.binmap & -(1ULL< 0) continue; c = expand_heap(n); if (!c) return 0; if (alloc_rev(c)) { @@ -361,7 +342,7 @@ void *malloc(size_t n) j = first_set(mask); lock_bin(j); c = mal.bins[j].head; - if (c != BIN_TO_CHUNK(j) && j == bin_index(c->csize)) { + if (c != BIN_TO_CHUNK(j)) { if (!pretrim(c, n, i, j)) unbin(c, j); unlock_bin(j); break; @@ -375,6 +356,17 @@ void *malloc(size_t n) return CHUNK_TO_MEM(c); } +void *__malloc0(size_t n) +{ + void *p = malloc(n); + if (p && !IS_MMAPPED(MEM_TO_CHUNK(p))) { + size_t *z; + n = (n + sizeof *z - 1)/sizeof *z; + for (z=p; n; n--, z++) if (*z) *z=0; + } + return p; +} + void *realloc(void *p, size_t n) { struct chunk *self, *next; @@ -412,6 +404,9 @@ void *realloc(void *p, size_t n) next = NEXT_CHUNK(self); + /* Crash on corrupted footer (likely from buffer overflow) */ + if (next->psize != self->csize) a_crash(); + /* Merge adjacent chunks if we need more space. This is not * a waste of time even if we fail to get enough space, because our * subsequent call to free would otherwise have to do the merge. */ @@ -465,19 +460,10 @@ void free(void *p) final_size = new_size = CHUNK_SIZE(self); next = NEXT_CHUNK(self); - for (;;) { - /* Replace middle of large chunks with fresh zero pages */ - 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 - __madvise((void *)a, b-a, MADV_DONTNEED); -#else - __mmap((void *)a, b-a, PROT_READ|PROT_WRITE, - MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, -1, 0); -#endif - } + /* Crash on corrupted footer (likely from buffer overflow) */ + if (next->psize != self->csize) a_crash(); + for (;;) { if (self->psize & next->csize & C_INUSE) { self->csize = final_size | C_INUSE; next->psize = final_size | C_INUSE; @@ -507,6 +493,9 @@ void free(void *p) } } + if (!(mal.binmap & 1ULL<csize = final_size; next->psize = final_size; unlock(mal.free_lock); @@ -516,8 +505,17 @@ void free(void *p) self->next->prev = self; self->prev->next = self; - if (!(mal.binmap & 1ULL<