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23ce05f906
SPDX is an international standard for documenting software license requirements. Remove the existing headers and replace with a brief SPDX preamble. See: https://spdx.dev/use/specifications/ The script used to convert the files is added to "tools", and the file header templates in headers/ are updated. Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
110 lines
2.6 KiB
C
110 lines
2.6 KiB
C
/* SPDX-License-Identifier: BSD-2-Clause */
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/* Copyright 1996-2017 The NASM Authors - All Rights Reserved */
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#include "file.h"
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/* ----------------------------------------------------------------------- *
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* Unix-style memory mapping, using mmap().
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* ----------------------------------------------------------------------- */
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#if defined(HAVE_FILENO) && defined(HAVE_MMAP)
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/*
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* System page size
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*/
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/* File scope since not all compilers like static data in inline functions */
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static size_t nasm_pagemask;
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static size_t get_pagemask(void)
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{
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size_t ps = 0;
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# if defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
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ps = sysconf(_SC_PAGESIZE);
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# elif defined(HAVE_GETPAGESIZE)
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ps = getpagesize();
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# elif defined(PAGE_SIZE)
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ps = PAGE_SIZE;
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# endif
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nasm_pagemask = ps = is_power2(ps) ? (ps - 1) : 0;
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return ps;
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}
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static inline size_t pagemask(void)
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{
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size_t pm = nasm_pagemask;
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if (unlikely(!pm))
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return get_pagemask();
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return pm;
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}
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/*
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* Try to map an input file into memory
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*/
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const void *nasm_map_file(FILE *fp, off_t start, off_t len)
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{
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const char *p;
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off_t astart; /* Aligned start */
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size_t salign; /* Amount of start adjustment */
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size_t alen; /* Aligned length */
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const size_t page_mask = pagemask();
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if (unlikely(!page_mask))
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return NULL; /* Page size undefined? */
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if (unlikely(!len))
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return NULL; /* Mapping nothing... */
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if (unlikely(len != (off_t)(size_t)len))
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return NULL; /* Address space insufficient */
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astart = start & ~(off_t)page_mask;
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salign = start - astart;
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alen = (len + salign + page_mask) & ~page_mask;
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p = mmap(NULL, alen, PROT_READ, MAP_SHARED, fileno(fp), astart);
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return unlikely(p == MAP_FAILED) ? NULL : p + salign;
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}
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/*
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* Unmap an input file
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*/
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void nasm_unmap_file(const void *p, size_t len)
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{
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const size_t page_mask = pagemask();
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uintptr_t astart;
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size_t salign;
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size_t alen;
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if (unlikely(!page_mask))
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return;
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astart = (uintptr_t)p & ~(uintptr_t)page_mask;
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salign = (uintptr_t)p - astart;
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alen = (len + salign + page_mask) & ~page_mask;
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munmap((void *)astart, alen);
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}
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/* ----------------------------------------------------------------------- *
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* No memory map support at all
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* XXX: Add a section with Windows support
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* ----------------------------------------------------------------------- */
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#else
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const void *nasm_map_file(FILE *fp, off_t start, off_t len)
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{
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(void)fp; (void)start; (void)len;
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return NULL;
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}
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void nasm_unmap_file(const void *p, size_t len)
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{
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(void)p; (void)len;
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}
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#endif
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