provide __stack_chk_fail_local in libc.a

[musl] / src / malloc / malloc.c

diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c
index 4044eb2..290fda1 100644 (file)
--- a/src/malloc/malloc.c
+++ b/src/malloc/malloc.c
@@ -13,7 +13,6 @@
 #define inline inline __attribute__((always_inline))
 #endif
 
-uintptr_t __brk(uintptr_t);
 void *__mmap(void *, size_t, int, int, int, off_t);
 int __munmap(void *, size_t);
 void *__mremap(void *, size_t, size_t, int, ...);
@@ -25,18 +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;
 
 
@@ -64,28 +60,27 @@ static struct {
 
 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 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 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 inline void unlock_bin(int i)
 {
-       if (!libc.threads_minus_1) return;
        unlock(mal.bins[i].lock);
 }
 
@@ -152,71 +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);
-#ifdef SHARED
-       mal.brk = mal.brk + PAGE_SIZE-1 & -PAGE_SIZE;
-#endif
-       mal.brk = mal.brk + 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)
@@ -353,7 +329,6 @@ void *malloc(size_t n)
        for (;;) {
                uint64_t mask = mal.binmap & -(1ULL<<i);
                if (!mask) {
-                       if (init_malloc(n) > 0) continue;
                        c = expand_heap(n);
                        if (!c) return 0;
                        if (alloc_rev(c)) {
@@ -367,7 +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;