desktop/unx/source/file_image_unx.c

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #include "file_image.h"
  21
  22 #include <unistd.h>
  23
  24 #include <errno.h>
  25 #include <fcntl.h>
  26
  27 #if defined(LINUX)
  28 #  ifndef __USE_BSD
  29 #    define __USE_BSD /* madvise, MADV_WILLNEED */
  30 #  endif
  31 #endif /* Linux */
  32
  33 #include <sys/mman.h>
  34 #include <sys/stat.h>
  35
  36 #include <string.h>
  37
  38 /*
  39  * file_image_open
  40  */
  41 int file_image_open (file_image * image, const char * filename)
  42 {
  43     int         result = 0;
  44     int         fd;
  45     struct stat st;
  46     void *      p;
  47
  48     if (image == 0)
  49         return (EINVAL);
  50
  51     image->m_base = MAP_FAILED, image->m_size = 0;
  52
  53     if ((fd = open (filename, O_RDONLY)) == -1)
  54         return (errno);
  55
  56     if (fstat (fd, &st) == -1)
  57     {
  58         result = errno;
  59         goto cleanup_and_leave;
  60     }
  61
  62     p = mmap (0, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
  63     if (p == MAP_FAILED)
  64     {
  65         result = errno;
  66         goto cleanup_and_leave;
  67     }
  68
  69     image->m_base = p, image->m_size = st.st_size;
  70
  71 cleanup_and_leave:
  72     close (fd);
  73     return (result);
  74 }
  75
  76 /*
  77  * file_image_pagein.
  78  */
  79 int file_image_pagein (file_image * image)
  80 {
  81     file_image    w;
  82     long          s;
  83     size_t        k;
  84     // force touching of each page despite the optimizer
  85     volatile char c = 0;
  86
  87     if (image == 0)
  88         return (EINVAL);
  89
  90     if ((w.m_base = image->m_base) == 0)
  91         return (EINVAL);
  92     if ((w.m_size = image->m_size) == 0)
  93         return (0);
  94
  95     if (madvise (w.m_base, w.m_size, MADV_WILLNEED) == -1)
  96         return (errno);
  97
  98     if ((s = sysconf (_SC_PAGESIZE)) == -1)
  99         s = 0x1000;
 100
 101     k = (size_t)(s);
 102     while (w.m_size > k)
 103     {
 104         c ^= ((char*)(w.m_base))[0];
 105         w.m_base  = (char*)(w.m_base) + k;
 106         w.m_size -= k;
 107     }
 108     if (w.m_size > 0)
 109     {
 110         c ^= ((char*)(w.m_base))[0];
 111     }
 112
 113     return (0);
 114 }
 115
 116 /*
 117  * file_image_close
 118  */
 119 int file_image_close (file_image * image)
 120 {
 121     if (image == 0)
 122         return (EINVAL);
 123
 124     if (munmap (image->m_base, image->m_size) == -1)
 125         return (errno);
 126
 127     image->m_base = 0, image->m_size = 0;
 128     return (0);
 129 }
 130
 131 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */