X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fmalloc%2Fmalloc.c;h=c38c46fe9e657e85fb3156ff7a7526f81d600827;hb=769f53598e781ffc89191520f3f8a93cb58db91f;hp=3c08c41e2fd6be42e765adc76e89113063e47d85;hpb=26031da0f83a2a3ed52190077931ee6c18dfd689;p=musl diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c index 3c08c41e..c38c46fe 100644 --- a/src/malloc/malloc.c +++ b/src/malloc/malloc.c @@ -1,3 +1,4 @@ +#define _GNU_SOURCE #include #include #include @@ -8,31 +9,30 @@ #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, ...); 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 { - 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; @@ -43,47 +43,44 @@ static struct { #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 & -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 *)((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 *)((char *)(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 IS_MMAPPED(c) !((c)->data[0] & (C_INUSE)) +#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); } @@ -114,19 +111,29 @@ static int first_set(uint64_t x) #endif } +static const unsigned char bin_tab[60] = { + 32,33,34,35,36,36,37,37,38,38,39,39, + 40,40,40,40,41,41,41,41,42,42,42,42,43,43,43,43, + 44,44,44,44,44,44,44,44,45,45,45,45,45,45,45,45, + 46,46,46,46,46,46,46,46,47,47,47,47,47,47,47,47, +}; + static int bin_index(size_t x) { x = x / SIZE_ALIGN - 1; if (x <= 32) return x; + if (x < 512) return bin_tab[x/8-4]; if (x > 0x1c00) return 63; - return ((union { float v; uint32_t r; }){ x }.r>>21) - 496; + return bin_tab[x/128-4] + 16; } static int bin_index_up(size_t x) { x = x / SIZE_ALIGN - 1; if (x <= 32) return x; - return ((union { float v; uint32_t r; }){ x }.r+0x1fffff>>21) - 496; + x--; + if (x < 512) return bin_tab[x/8-4] + 1; + return bin_tab[x/128-4] + 17; } #if 0 @@ -137,8 +144,8 @@ 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)), - 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); @@ -150,67 +157,52 @@ 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; + /* 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; - w = MEM_TO_CHUNK(new); - w->data[-1] = n | C_INUSE; - w->data[0] = 0 | C_INUSE; + lock(heap_lock); - w = MEM_TO_CHUNK(mal.brk); - w->data[0] = n | C_INUSE; - mal.brk = new; - - unlock(mal.brk_lock); - - return w; -fail: - unlock(mal.brk_lock); - return 0; -} - -static int init_malloc() -{ - static int init, waiters; - int state; - struct chunk *c; - - if (init == 2) return 0; - - 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(1); + /* 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->data[-1] = 0 | C_INUSE; - free(CHUNK_TO_MEM(c)); + unlock(heap_lock); - a_store(&init, 2); - if (waiters) __wake(&init, -1, 1); - return 0; + return w; } static int adjust_size(size_t *n) @@ -235,18 +227,18 @@ static void unbin(struct chunk *c, int i) a_and_64(&mal.binmap, ~(1ULL<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; - while (!((k=c->data[0]) & C_INUSE)) { + while (!((k=c->csize) & C_INUSE)) { i = bin_index(k); lock_bin(i); - if (c->data[0] == k) { + if (c->csize == k) { unbin(c, i); unlock_bin(i); return 1; @@ -260,10 +252,10 @@ static int alloc_rev(struct chunk *c) { 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); - if (c->data[-1] == k) { + if (c->psize == k) { unbin(PREV_CHUNK(c), i); unlock_bin(i); return 1; @@ -300,10 +292,10 @@ 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->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; } @@ -317,10 +309,10 @@ static void trim(struct chunk *self, size_t 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)); } @@ -333,13 +325,13 @@ void *malloc(size_t n) if (adjust_size(&n) < 0) return 0; if (n > MMAP_THRESHOLD) { - size_t len = n + PAGE_SIZE - 1 & -PAGE_SIZE; + size_t len = n + OVERHEAD + PAGE_SIZE - 1 & -PAGE_SIZE; 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); } @@ -347,21 +339,20 @@ void *malloc(size_t n) for (;;) { uint64_t mask = mal.binmap & -(1ULL<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; - if (c != BIN_TO_CHUNK(j) && j == bin_index(c->data[0])) { + if (c != BIN_TO_CHUNK(j)) { if (!pretrim(c, n, i, j)) unbin(c, j); unlock_bin(j); break; @@ -375,6 +366,17 @@ 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; @@ -389,10 +391,12 @@ void *realloc(void *p, size_t n) 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; + /* Crash on realloc of freed chunk */ + if (extra & 1) a_crash(); if (newlen < PAGE_SIZE && (new = malloc(n))) { memcpy(new, p, n-OVERHEAD); free(p); @@ -404,12 +408,15 @@ void *realloc(void *p, size_t n) 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); } 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. */ @@ -422,8 +429,8 @@ void *realloc(void *p, size_t n) 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) { @@ -451,9 +458,11 @@ void free(void *p) 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 */ + if (extra & 1) a_crash(); __munmap(base, len); return; } @@ -461,26 +470,17 @@ 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->data[-1] & next->data[0] & 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(); - if (self->data[-1] & next->data[0] & C_INUSE) { - self->data[0] = final_size | C_INUSE; - next->data[-1] = final_size | C_INUSE; + for (;;) { + 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); - if (self->data[-1] & next->data[0] & C_INUSE) + if (self->psize & next->csize & C_INUSE) break; unlock(mal.free_lock); unlock_bin(i); @@ -503,8 +503,11 @@ void free(void *p) } } - self->data[0] = final_size; - next->data[-1] = final_size; + if (!(mal.binmap & 1ULL<csize = final_size; + next->psize = final_size; unlock(mal.free_lock); self->next = BIN_TO_CHUNK(i); @@ -512,8 +515,17 @@ void free(void *p) self->next->prev = self; self->prev->next = self; - if (!(mal.binmap & 1ULL<