From 6ef9cc37f0ea151a54e5c8a19950a6d5b6ff8a96 Mon Sep 17 00:00:00 2001 From: Siddhesh Poyarekar Date: Wed, 5 Sep 2012 21:49:00 +0530 Subject: Return requested size for malloc_usable_size when MALLOC_CHECK_ > 0 [BZ #1349] malloc_usable_size returns the usable size in an allocated chunk, which may be >= the requested size. In the case of MALLOC_CHECK_ being exported to > 0 however, only the requested size is usable, since a magic value is written at the end of the request size to trap writes beyond request bounds. Hence, when MALLOC_CHECK_ is exported to > 0, malloc_usable_size() should return the request size. --- malloc/tst-malloc-usable.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 malloc/tst-malloc-usable.c (limited to 'malloc/tst-malloc-usable.c') diff --git a/malloc/tst-malloc-usable.c b/malloc/tst-malloc-usable.c new file mode 100644 index 0000000000..18decd852c --- /dev/null +++ b/malloc/tst-malloc-usable.c @@ -0,0 +1,49 @@ +/* Ensure that malloc_usable_size returns the request size with + MALLOC_CHECK_ exported to a positive value. + + Copyright (C) 2012 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include + +static int +do_test (void) +{ + size_t usable_size; + void *p = malloc (7); + if (!p) + { + printf ("memory allocation failed\n"); + return 1; + } + + usable_size = malloc_usable_size (p); + if (usable_size != 7) + { + printf ("malloc_usable_size: expected 7 but got %zu\n", usable_size); + return 1; + } + + memset (p, 0, usable_size); + free (p); + return 0; +} + +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c" -- cgit v1.2.3