135 lines
3.8 KiB
C
135 lines
3.8 KiB
C
/* aligned memory allocation
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Copyright 2022-2025 Free Software Foundation, Inc.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Written by Paul Eggert. */
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#ifndef ALIGNALLOC_H_
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#define ALIGNALLOC_H_
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/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE, _GL_ATTRIBUTE_ALLOC_SIZE,
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_GL_ATTRIBUTE_MALLOC, _GL_ATTRIBUTE_RETURNS_NONNULL, HAVE_POSIX_MEMALIGN. */
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#if !_GL_CONFIG_H_INCLUDED
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#error "Please include config.h first."
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#endif
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#include <errno.h>
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#include <stdlib.h>
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#include "idx.h"
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#if defined __CHERI_PURE_CAPABILITY__
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# include <cheri.h>
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#endif
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_GL_INLINE_HEADER_BEGIN
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#ifndef ALIGNALLOC_INLINE
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# define ALIGNALLOC_INLINE _GL_INLINE
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#endif
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Whether aligned_alloc supports any power-of-two alignment,
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returns a nonnull pointer for size-zero allocations,
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and sets errno on failure. */
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#if 2 < __GLIBC__ + (16 <= __GLIBC_MINOR__)
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# define ALIGNALLOC_VIA_ALIGNED_ALLOC 1
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#else
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# define ALIGNALLOC_VIA_ALIGNED_ALLOC 0
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#endif
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/* Work around AddressSanitizer bug.
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104262
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https://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20220124/1001910.html
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*/
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#ifdef __SANITIZE_ADDRESS__
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# undef ALIGNALLOC_VIA_ALIGNED_ALLOC
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# define ALIGNALLOC_VIA_ALIGNED_ALLOC 0
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#endif
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#ifdef __has_feature
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# if __has_feature (address_sanitizer)
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# undef ALIGNALLOC_VIA_ALIGNED_ALLOC
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# define ALIGNALLOC_VIA_ALIGNED_ALLOC 0
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# endif
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#endif
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#if ALIGNALLOC_VIA_ALIGNED_ALLOC || HAVE_POSIX_MEMALIGN
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/* Free storage allocated via alignalloc. Do nothing if PTR is null. */
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ALIGNALLOC_INLINE void
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alignfree (void *ptr)
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{
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free (ptr);
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}
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/* Return an ALIGNMENT-aligned pointer to new storage of size SIZE,
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or a null pointer (setting errno) if memory is exhausted.
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ALIGNMENT must be a power of two.
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If SIZE is zero, on success return a unique pointer each time.
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To free storage later, call alignfree. */
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ALIGNALLOC_INLINE
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_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2))
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/* _GL_ATTRIBUTE_DEALLOC (alignfree, 1) */
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void *
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alignalloc (idx_t alignment, idx_t size)
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{
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if ((size_t) -1 < alignment)
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alignment = (size_t) -1;
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if ((size_t) -1 < size)
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size = (size_t) -1;
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# if ALIGNALLOC_VIA_ALIGNED_ALLOC
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return aligned_alloc (alignment, size);
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# else
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void *ptr = NULL;
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if (alignment < sizeof (void *))
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alignment = sizeof (void *);
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/* Work around posix_memalign glitch by treating a 0 size as if it were 1,
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so that returning NULL is equivalent to failing. */
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errno = posix_memalign (&ptr, alignment, size ? size : 1);
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# if defined __CHERI_PURE_CAPABILITY__
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if (ptr != NULL)
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ptr = cheri_bounds_set (ptr, size);
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# endif
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return ptr;
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# endif
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}
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#else /* ! (ALIGNALLOC_VIA_ALIGNED_ALLOC || HAVE_POSIX_MEMALIGN) */
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void alignfree (void *);
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void *alignalloc (idx_t, idx_t)
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_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2))
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_GL_ATTRIBUTE_DEALLOC (alignfree, 1);
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#endif
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/* Like alignalloc, but die instead of returning a null pointer. */
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void *xalignalloc (idx_t, idx_t)
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_GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_ALLOC_SIZE ((2))
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_GL_ATTRIBUTE_RETURNS_NONNULL /* _GL_ATTRIBUTE_DEALLOC (alignfree, 1) */;
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#ifdef __cplusplus
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}
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#endif
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_GL_INLINE_HEADER_END
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#endif /* !ALIGNALLOC_H_ */
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