From d1417176a35d27ffb8da0ffb1e33154163b6eeb2 Mon Sep 17 00:00:00 2001 From: DJ Delorie Date: Tue, 21 Mar 2023 00:46:43 -0400 Subject: aligned_alloc: conform to C17 This patch adds the strict checking for power-of-two alignments in aligned_alloc(), and updates the manual accordingly. Reviewed-by: Carlos O'Donell --- malloc/Makefile | 6 ++- malloc/malloc-debug.c | 9 ++++- malloc/malloc.c | 26 +++++++++++-- malloc/tst-aligned-alloc-static.c | 1 + malloc/tst-aligned-alloc.c | 80 +++++++++++++++++++++++++++++++++++++++ 5 files changed, 116 insertions(+), 6 deletions(-) create mode 100644 malloc/tst-aligned-alloc-static.c create mode 100644 malloc/tst-aligned-alloc.c (limited to 'malloc') diff --git a/malloc/Makefile b/malloc/Makefile index 21c5a7c..ce6ebcf 100644 --- a/malloc/Makefile +++ b/malloc/Makefile @@ -44,11 +44,13 @@ tests := mallocbug tst-malloc tst-valloc tst-calloc tst-obstack \ tst-safe-linking \ tst-mallocalign1 \ tst-memalign-2 \ - tst-memalign-3 + tst-memalign-3 \ + tst-aligned-alloc tests-static := \ tst-interpose-static-nothread \ - tst-interpose-static-thread + tst-interpose-static-thread \ + tst-aligned-alloc-static # Test for the malloc_set_state symbol removed in glibc 2.25. ifeq ($(have-GLIBC_2.23)$(build-shared),yesyes) diff --git a/malloc/malloc-debug.c b/malloc/malloc-debug.c index 3867d15..da9d234 100644 --- a/malloc/malloc-debug.c +++ b/malloc/malloc-debug.c @@ -299,7 +299,14 @@ __debug_memalign (size_t alignment, size_t bytes) return _debug_mid_memalign (alignment, bytes, RETURN_ADDRESS (0)); } strong_alias (__debug_memalign, memalign) -strong_alias (__debug_memalign, aligned_alloc) +static void * +__debug_aligned_alloc (size_t alignment, size_t bytes) +{ + if (!powerof2 (alignment) || alignment == 0) + return NULL; + return _debug_mid_memalign (alignment, bytes, RETURN_ADDRESS (0)); +} +strong_alias (__debug_aligned_alloc, aligned_alloc) static void * __debug_pvalloc (size_t bytes) diff --git a/malloc/malloc.c b/malloc/malloc.c index e33ed66..5d8b61d 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -3528,6 +3528,29 @@ __libc_memalign (size_t alignment, size_t bytes) void *address = RETURN_ADDRESS (0); return _mid_memalign (alignment, bytes, address); } +libc_hidden_def (__libc_memalign) + +/* For ISO C17. */ +void * +weak_function +aligned_alloc (size_t alignment, size_t bytes) +{ + if (!__malloc_initialized) + ptmalloc_init (); + +/* Similar to memalign, but starting with ISO C17 the standard + requires an error for alignments that are not supported by the + implementation. Valid alignments for the current implementation + are non-negative powers of two. */ + if (!powerof2 (alignment) || alignment == 0) + { + __set_errno (EINVAL); + return 0; + } + + void *address = RETURN_ADDRESS (0); + return _mid_memalign (alignment, bytes, address); +} static void * _mid_memalign (size_t alignment, size_t bytes, void *address) @@ -3618,9 +3641,6 @@ _mid_memalign (size_t alignment, size_t bytes, void *address) ar_ptr == arena_for_chunk (mem2chunk (p))); return tag_new_usable (p); } -/* For ISO C11. */ -weak_alias (__libc_memalign, aligned_alloc) -libc_hidden_def (__libc_memalign) void * __libc_valloc (size_t bytes) diff --git a/malloc/tst-aligned-alloc-static.c b/malloc/tst-aligned-alloc-static.c new file mode 100644 index 0000000..d504473 --- /dev/null +++ b/malloc/tst-aligned-alloc-static.c @@ -0,0 +1 @@ +#include "tst-aligned-alloc.c" diff --git a/malloc/tst-aligned-alloc.c b/malloc/tst-aligned-alloc.c new file mode 100644 index 0000000..8bd6527 --- /dev/null +++ b/malloc/tst-aligned-alloc.c @@ -0,0 +1,80 @@ +/* Test for C17 alignment requirements. + Copyright (C) 2023 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 +#include +#include +#include +#include +#include + +static int +do_test (void) +{ + void *p1; + void *p2; + void *p3; + void *p4; + void *p5; + + errno = 0; + + /* The implementation supports alignments that are non-negative powers of 2. + We test 5 distinct conditions here: + - A non-negative power of 2 alignment e.g. 64. + - A degenerate zero power of 2 alignment e.g. 1. + - A non-power-of-2 alignment e.g. 65. + - A zero alignment. + - A corner case SIZE_MAX / 2 + 1 alignment. + */ + + p1 = aligned_alloc (64, 64); + + if (p1 == NULL) + FAIL_EXIT1 ("aligned_alloc(64, 64) failed"); + + p2 = aligned_alloc (1, 64); + + if (p2 == NULL) + FAIL_EXIT1 ("aligned_alloc(1, 64) failed"); + + p3 = aligned_alloc (65, 64); + + if (p3 != NULL) + FAIL_EXIT1 ("aligned_alloc(65, 64) did not fail"); + + p4 = aligned_alloc (0, 64); + + if (p4 != NULL) + FAIL_EXIT1 ("aligned_alloc(0, 64) did not fail"); + + /* This is an alignment like 0x80000000...UL */ + p5 = aligned_alloc (SIZE_MAX / 2 + 1, 64); + + if (p5 != NULL) + FAIL_EXIT1 ("aligned_alloc(SIZE_MAX/2+1, 64) did not fail"); + + free (p1); + free (p2); + return 0; +} + +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c" -- cgit v1.1