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 #include <sys/mman.h>
  28 #include <sys/stat.h>
  29
  30 #include <string.h>
  31
  32 /*
  33  * file_image_open
  34  */
  35 int file_image_open (file_image * image, const char * filename)
  36 {
  37     int         result = 0;
  38     int         fd;
  39     struct stat st;
  40     void *      p;
  41
  42     if (image == NULL)
  43         return EINVAL;
  44
  45     image->m_base = MAP_FAILED;
  46     image->m_size = 0;
  47
  48     if ((fd = open (filename, O_RDONLY)) == -1)
  49         return errno;
  50
  51     if (fstat (fd, &st) == -1)
  52     {
  53         result = errno;
  54         goto cleanup_and_leave;
  55     }
  56
  57     p = mmap (NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
  58     if (p == MAP_FAILED)
  59     {
  60         result = errno;
  61         goto cleanup_and_leave;
  62     }
  63
  64     image->m_base = p;
  65     image->m_size = st.st_size;
  66
  67 cleanup_and_leave:
  68     close (fd);
  69     return result;
  70 }
  71
  72 /*
  73  * file_image_pagein.
  74  */
  75 int file_image_pagein (file_image * image)
  76 {
  77     long s = -1;
  78     volatile char c =0;
  79     size_t idx;
  80
  81     if (image == NULL)
  82         return EINVAL;
  83     if (image->m_base == NULL)
  84         return EINVAL;
  85     if (image->m_size == 0)
  86         return 0;
  87
  88     if (madvise (image->m_base, image->m_size, MADV_WILLNEED) == -1)
  89         return errno;
  90
  91     s = sysconf (_SC_PAGESIZE);
  92     if (s == -1)
  93         s = 0x1000;
  94     // force touching of each page despite the optimizer
  95     for(idx = 0; idx < image->m_size; idx += (size_t)s)
  96     {
  97         c ^= ((volatile const char*)(image->m_base))[idx];
  98     }
  99     c ^= ((volatile const char*)(image->m_base))[image->m_size-1];
 100
 101     return 0;
 102 }
 103
 104 /*
 105  * file_image_close
 106  */
 107 int file_image_close (file_image * image)
 108 {
 109     if (image == NULL)
 110         return EINVAL;
 111
 112     if (munmap (image->m_base, image->m_size) == -1)
 113         return errno;
 114
 115     image->m_base = NULL;
 116     image->m_size = 0;
 117     return 0;
 118 }
 119
 120 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */