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/* ----------------------------------------------------------------------- *
*
* Copyright 1996-2017 The NASM Authors - All Rights Reserved
* See the file AUTHORS included with the NASM distribution for
* the specific copyright holders.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following
* conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* ----------------------------------------------------------------------- */
#include "file.h"
/* ----------------------------------------------------------------------- *
* Unix-style memory mapping, using mmap().
* ----------------------------------------------------------------------- */
#if defined(HAVE_FILENO) && defined(HAVE_MMAP)
/*
* System page size
*/
/* File scope since not all compilers like static data in inline functions */
static size_t nasm_pagemask;
static size_t get_pagemask(void)
{
size_t ps = 0;
# if defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
ps = sysconf(_SC_PAGESIZE);
# elif defined(HAVE_GETPAGESIZE)
ps = getpagesize();
# elif defined(PAGE_SIZE)
ps = PAGE_SIZE;
# endif
nasm_pagemask = ps = is_power2(ps) ? (ps - 1) : 0;
return ps;
}
static inline size_t pagemask(void)
{
size_t pm = nasm_pagemask;
if (unlikely(!pm))
return get_pagemask();
return pm;
}
/*
* Try to map an input file into memory
*/
const void *nasm_map_file(FILE *fp, off_t start, off_t len)
{
const char *p;
off_t astart; /* Aligned start */
size_t salign; /* Amount of start adjustment */
size_t alen; /* Aligned length */
const size_t page_mask = pagemask();
if (unlikely(!page_mask))
return NULL; /* Page size undefined? */
if (unlikely(!len))
return NULL; /* Mapping nothing... */
if (unlikely(len != (off_t)(size_t)len))
return NULL; /* Address space insufficient */
astart = start & ~(off_t)page_mask;
salign = start - astart;
alen = (len + salign + page_mask) & ~page_mask;
p = mmap(NULL, alen, PROT_READ, MAP_SHARED, fileno(fp), astart);
return unlikely(p == MAP_FAILED) ? NULL : p + salign;
}
/*
* Unmap an input file
*/
void nasm_unmap_file(const void *p, size_t len)
{
const size_t page_mask = pagemask();
uintptr_t astart;
size_t salign;
size_t alen;
if (unlikely(!page_mask))
return;
astart = (uintptr_t)p & ~(uintptr_t)page_mask;
salign = (uintptr_t)p - astart;
alen = (len + salign + page_mask) & ~page_mask;
munmap((void *)astart, alen);
}
/* ----------------------------------------------------------------------- *
* No memory map support at all
* XXX: Add a section with Windows support
* ----------------------------------------------------------------------- */
#else
const void *nasm_map_file(FILE *fp, off_t start, off_t len)
{
(void)fp; (void)start; (void)len;
return NULL;
}
void nasm_unmap_file(const void *p, size_t len)
{
(void)p; (void)len;
}
#endif
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