From c9f415d7ea2dace5bf77f6518b6afc36bb7a5732 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Tue, 17 Apr 2018 18:36:19 -0400 Subject: allow interposition/replacement of allocator (malloc) replacement is subject to conditions on the replacement functions. they may only call functions which are async-signal-safe, as specified either by POSIX or as an implementation-defined extension. if any allocator functions are replaced, at least malloc, realloc, and free must be provided. if calloc is not provided, it will behave as malloc+memset. any of the memalign-family functions not provided will fail with ENOMEM. in order to implement the above properties, calloc and __memalign check that they are using their own malloc or free, respectively. choice to check malloc or free is based on considerations of supporting __simple_malloc. in order to make this work, calloc is split into separate versions for __simple_malloc and full malloc; commit ba819787ee93ceae94efd274f7849e317c1bff58 already did most of the split anyway, and completing it saves an extra call frame. previously, use of -Bsymbolic-functions made dynamic interposition impossible. now, we are using an explicit dynamic-list, so add allocator functions to the list. most are not referenced anyway, but all are added for completeness. --- src/malloc/lite_malloc.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'src/malloc/lite_malloc.c') diff --git a/src/malloc/lite_malloc.c b/src/malloc/lite_malloc.c index 701f60b4..29cccb10 100644 --- a/src/malloc/lite_malloc.c +++ b/src/malloc/lite_malloc.c @@ -47,4 +47,14 @@ static void *__simple_malloc(size_t n) } weak_alias(__simple_malloc, malloc); -weak_alias(__simple_malloc, __malloc0); + +static void *__simple_calloc(size_t m, size_t n) +{ + if (n && m > (size_t)-1/n || malloc != __simple_malloc) { + errno = ENOMEM; + return 0; + } + return __simple_malloc(n * m); +} + +weak_alias(__simple_calloc, calloc); -- cgit v1.2.1