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. --- dynamic.list | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'dynamic.list') diff --git a/dynamic.list b/dynamic.list index 8b4f2366..686f8eb4 100644 --- a/dynamic.list +++ b/dynamic.list @@ -6,6 +6,15 @@ stdin; stdout; stderr; +malloc; +calloc; +realloc; +free; +memalign; +posix_memalign; +aligned_alloc; +malloc_usable_size; + timezone; daylight; tzname; -- cgit 1.4.1