desktop/source/pagein/file_image_unx.c

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   5  * Copyright 2008 by Sun Microsystems, Inc.
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   7  * OpenOffice.org - a multi-platform office productivity suite
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   9  * $RCSfile: file_image_unx.c,v $
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  21  * GNU Lesser General Public License version 3 for more details
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  30
  31 #include "file_image.h"
  32
  33 #include <unistd.h>
  34
  35 #include <errno.h>
  36 #include <fcntl.h>
  37
  38 #if defined(LINUX)
  39 #  ifndef __USE_BSD
  40 #    define __USE_BSD /* madvise, MADV_WILLNEED */
  41 #  endif
  42 #endif /* Linux */
  43
  44 #include <sys/mman.h>
  45 #include <sys/stat.h>
  46
  47 #include <string.h>
  48
  49 /*
  50  * file_image_open
  51  */
  52 int file_image_open (file_image * image, const char * filename)
  53 {
  54     int         result = 0;
  55     int         fd;
  56     struct stat st;
  57     void *      p;
  58
  59     if (image == 0)
  60         return (EINVAL);
  61
  62     image->m_base = MAP_FAILED, image->m_size = 0;
  63
  64     if ((fd = open (filename, O_RDONLY)) == -1)
  65         return (errno);
  66
  67     if (fstat (fd, &st) == -1)
  68     {
  69         result = errno;
  70         goto cleanup_and_leave;
  71     }
  72
  73     p = mmap (0, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
  74     if (p == MAP_FAILED)
  75     {
  76         result = errno;
  77         goto cleanup_and_leave;
  78     }
  79
  80     image->m_base = p, image->m_size = st.st_size;
  81
  82 cleanup_and_leave:
  83     close (fd);
  84     return (result);
  85 }
  86
  87 /*
  88  * file_image_pagein.
  89  */
  90 int file_image_pagein (file_image * image)
  91 {
  92     file_image    w;
  93     long          s;
  94     size_t        k;
  95     volatile char c = 0;
  96
  97     if (image == 0)
  98         return (EINVAL);
  99
 100     if ((w.m_base = image->m_base) == 0)
 101         return (EINVAL);
 102     if ((w.m_size = image->m_size) == 0)
 103         return (0);
 104
 105     if (madvise (w.m_base, w.m_size, MADV_WILLNEED) == -1)
 106     {
 107 #ifndef MACOSX
 108         return (errno);
 109 #else
 110         /* madvise MADV_WILLNEED need not succeed here */
 111         /* but that is fine */
 112 #endif
 113     }
 114
 115
 116 #ifndef MACOSX
 117     if ((s = sysconf (_SC_PAGESIZE)) == -1)
 118         s = 0x1000;
 119 #else
 120     s = getpagesize();
 121 #endif
 122
 123     k = (size_t)(s);
 124     while (w.m_size > k)
 125     {
 126         c ^= ((char*)(w.m_base))[0];
 127         w.m_base  = (char*)(w.m_base) + k;
 128         w.m_size -= k;
 129     }
 130     if (w.m_size > 0)
 131     {
 132         c ^= ((char*)(w.m_base))[0];
 133         w.m_base  = (char*)(w.m_base) + w.m_size;
 134         w.m_size -= w.m_size;
 135     }
 136
 137     return (0);
 138 }
 139
 140 /*
 141  * file_image_close
 142  */
 143 int file_image_close (file_image * image)
 144 {
 145     if (image == 0)
 146         return (EINVAL);
 147
 148     if (munmap (image->m_base, image->m_size) == -1)
 149         return (errno);
 150
 151     image->m_base = 0, image->m_size = 0;
 152     return (0);
 153 }