489102d28e
(see the comments starting at <https://reviews.llvm.org/D100581#2795966> "[Clang] -Wunused-but-set-parameter and -Wunused-but-set-variable" that warning on volatile variables is intentional) Change-Id: I2f9d0ed4a7f11f0bc2bdea57c0434654cd9fdf95 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/116813 Tested-by: Jenkins Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
121 lines
2.8 KiB
C
121 lines
2.8 KiB
C
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* This file incorporates work covered by the following license notice:
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed
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* with this work for additional information regarding copyright
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* ownership. The ASF licenses this file to you under the Apache
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* License, Version 2.0 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.apache.org/licenses/LICENSE-2.0 .
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*/
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#include "file_image.h"
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#include <unistd.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <string.h>
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/*
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* file_image_open
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*/
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int file_image_open (file_image * image, const char * filename)
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{
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int result = 0;
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int fd;
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struct stat st;
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void * p;
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if (image == NULL)
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return EINVAL;
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image->m_base = MAP_FAILED;
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image->m_size = 0;
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if ((fd = open (filename, O_RDONLY)) == -1)
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return errno;
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if (fstat (fd, &st) == -1)
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{
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result = errno;
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goto cleanup_and_leave;
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}
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p = mmap (NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
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if (p == MAP_FAILED)
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{
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result = errno;
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goto cleanup_and_leave;
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}
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image->m_base = p;
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image->m_size = st.st_size;
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cleanup_and_leave:
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close (fd);
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return result;
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}
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/*
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* file_image_pagein.
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*/
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int file_image_pagein (file_image * image)
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{
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long s = -1;
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volatile char c =0;
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size_t idx;
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if (image == NULL)
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return EINVAL;
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if (image->m_base == NULL)
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return EINVAL;
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if (image->m_size == 0)
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return 0;
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if (madvise (image->m_base, image->m_size, MADV_WILLNEED) == -1)
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return errno;
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s = sysconf (_SC_PAGESIZE);
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if (s == -1)
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s = 0x1000;
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// force touching of each page despite the optimizer
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for(idx = 0; idx < image->m_size; idx += (size_t)s)
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{
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c ^= ((volatile const char*)(image->m_base))[idx];
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}
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c ^= ((volatile const char*)(image->m_base))[image->m_size-1];
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(void)c; // silence Clang 13 trunk -Wunused-but-set-variable
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return 0;
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}
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/*
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* file_image_close
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*/
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int file_image_close (file_image * image)
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{
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if (image == NULL)
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return EINVAL;
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if (munmap (image->m_base, image->m_size) == -1)
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return errno;
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image->m_base = NULL;
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image->m_size = 0;
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return 0;
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}
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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