pkgbuilds/wiifuse/src/wiifuse-0.2.0/io.c

   1 /*
   2  *  Copyright (C) 2008 dhewg, #wiidev efnet
   3  *
   4  *  this file is part of wiifuse
   5  *  http://wiibrew.org/index.php?title=Wiifuse
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the Free Software
  19  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include <stdio.h>
  23
  24 #include "io.h"
  25
  26 int io_read (void *ptr, size_t size, struct image_file *image, u64 offset) {
  27         size_t bytes;
  28
  29         if (fseeko (image->fp, offset, SEEK_SET)) {
  30                 perror ("io_seek");
  31                 return -1;
  32         }
  33
  34         bytes = fread (ptr, 1, size, image->fp);
  35
  36         if (bytes != size)
  37                 perror ("io_read");
  38
  39         return bytes;
  40 }
  41
  42 int decrypt_block (struct image_file *image, u32 part, u32 block) {
  43         if (block == image->parts[part].cached_block)
  44                 return 0;
  45
  46         LOG (3, "decrypting part/block %u/%08x", part, block);
  47
  48         if (io_read (image->parts[part].dec_buffer, 0x8000, image,
  49                      image->parts[part].offset +
  50                      image->parts[part].data_offset + 0x8000ull * block)
  51             != 0x8000) {
  52                 perror ("decrypt read");
  53                 return -1;
  54         }
  55
  56         AES_cbc_encrypt (&image->parts[part].dec_buffer[0x400],
  57                          image->parts[part].cache, 0x7c00,
  58                          &image->parts[part].key,
  59                          &image->parts[part].dec_buffer[0x3d0], 0);
  60
  61         image->parts[part].cached_block = block;
  62
  63         return 0;
  64 }
  65
  66 size_t io_read_part (void *ptr, size_t size, struct image_file *image,
  67                      u32 part, u64 offset) {
  68         u32 block = offset / 0x7c00;
  69         u32 cache_offset = offset % 0x7c00;
  70         u32 cache_size;
  71         void *dst = ptr;
  72
  73         if (!image->parts[part].is_encrypted)
  74                 return io_read (ptr, size, image,
  75                                 image->parts[part].offset + offset);
  76
  77         while (size) {
  78                 if (decrypt_block (image, part, block))
  79                         return dst - ptr;
  80
  81                 cache_size = size;
  82                 if (cache_size + cache_offset > 0x7c00)
  83                         cache_size = 0x7c00 - cache_offset;
  84
  85                 memcpy (dst, image->parts[part].cache + cache_offset,
  86                         cache_size);
  87                 dst += cache_size;
  88                 size -= cache_size;
  89                 cache_offset = 0;
  90
  91                 block++;
  92         }
  93
  94         return dst - ptr;
  95 }
  96