From 759a6ef877fe2284cce166b470209d2b62993665 Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Sat, 14 Jul 2018 05:37:51 +0000 Subject: ensure ENOMEM is preserved in errno when appropriate rcu_read_unlock may clobber errno, so it's our responsibility to preserve it. Fortunately, ENOMEM is the only error which real_malloc can fail with. Also, do not set errno for posix_memalign. --- ext/mwrap/mwrap.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/ext/mwrap/mwrap.c b/ext/mwrap/mwrap.c index fa52631..7ae892c 100644 --- a/ext/mwrap/mwrap.c +++ b/ext/mwrap/mwrap.c @@ -401,10 +401,9 @@ static void *internal_memalign(size_t alignment, size_t size, uintptr_t caller) for (; alignment < sizeof(struct alloc_hdr); alignment *= 2) ; /* double alignment until >= sizeof(struct alloc_hdr) */ if (__builtin_add_overflow(size, alignment, &asize) || - __builtin_add_overflow(asize, sizeof(struct alloc_hdr), &asize)) { - errno = ENOMEM; + __builtin_add_overflow(asize, sizeof(struct alloc_hdr), &asize)) return 0; - } + /* assert(asize == (alignment + size + sizeof(struct alloc_hdr))); */ rcu_read_lock(); l = update_stats_rcu(size, caller); @@ -423,7 +422,9 @@ static void *internal_memalign(size_t alignment, size_t size, uintptr_t caller) void *memalign(size_t alignment, size_t size) { - return internal_memalign(alignment, size, RETURN_ADDRESS(0)); + void *p = internal_memalign(alignment, size, RETURN_ADDRESS(0)); + if (caa_unlikely(!p)) errno = ENOMEM; + return p; } static bool is_power_of_two(size_t n) { return (n & (n - 1)) == 0; } @@ -445,7 +446,9 @@ void cfree(void *) __attribute__((alias("free"))); void *valloc(size_t size) { - return internal_memalign(page_size, size, RETURN_ADDRESS(0)); + void *p = internal_memalign(page_size, size, RETURN_ADDRESS(0)); + if (caa_unlikely(!p)) errno = ENOMEM; + return p; } #if __GNUC__ < 7 @@ -461,13 +464,16 @@ void *valloc(size_t size) void *pvalloc(size_t size) { size_t alignment = page_size; + void *p; if (add_overflow_p(size, alignment)) { errno = ENOMEM; return 0; } size = size_align(size, alignment); - return internal_memalign(alignment, size, RETURN_ADDRESS(0)); + p = internal_memalign(alignment, size, RETURN_ADDRESS(0)); + if (caa_unlikely(!p)) errno = ENOMEM; + return p; } void *malloc(size_t size) @@ -490,6 +496,7 @@ void *malloc(size_t size) p = hdr2ptr(h); } rcu_read_unlock(); + if (caa_unlikely(!p)) errno = ENOMEM; return p; } @@ -518,6 +525,7 @@ void *calloc(size_t nmemb, size_t size) memset(p, 0, size); } rcu_read_unlock(); + if (caa_unlikely(!p)) errno = ENOMEM; return p; } @@ -552,6 +560,7 @@ void *realloc(void *ptr, size_t size) memcpy(p, ptr, old->size < size ? old->size : size); free(ptr); } + if (caa_unlikely(!p)) errno = ENOMEM; return p; } -- cgit v1.2.3-24-ge0c7