tools/scramble.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2002 by Björn Stenberg
  11  *
  12  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22
  23 int main (int argc, char** argv)
  24 {
  25     unsigned long length,i,slen;
  26     unsigned char *inbuf,*outbuf;
  27     unsigned short crc=0;
  28     unsigned char header[24];
  29     unsigned char *iname = argv[1];
  30     unsigned char *oname = argv[2];
  31     int headerlen = 6;
  32     FILE* file;
  33
  34     if (argc < 3) {
  35        printf("usage: %s [-fm] <input file> <output file>\n",argv[0]);
  36        return -1;
  37     }
  38
  39     if (argv[1][0] == '-') { /* assume any parameter is -fm :-) */
  40         headerlen = 24;
  41         iname = argv[2];
  42         oname = argv[3];
  43     }
  44
  45     /* open file */
  46     file = fopen(iname,"rb");
  47     if (!file) {
  48        perror(iname);
  49        return -1;
  50     }
  51     fseek(file,0,SEEK_END);
  52     length = ftell(file);
  53     length = (length + 3) & ~3; /* Round up to nearest 4 byte boundary */
  54
  55     if ((length + headerlen) >= 0x32000) {
  56         printf("error: max firmware size is 200KB!\n");
  57         fclose(file);
  58         return -1;
  59     }
  60
  61     fseek(file,0,SEEK_SET);
  62     inbuf = malloc(length);
  63     outbuf = malloc(length);
  64     if ( !inbuf || !outbuf ) {
  65        printf("out of memory!\n");
  66        return -1;
  67     }
  68
  69     /* read file */
  70     i=fread(inbuf,1,length,file);
  71     if ( !i ) {
  72        perror(iname);
  73        return -1;
  74     }
  75     fclose(file);
  76
  77     /* scramble */
  78     slen = length/4;
  79     for (i = 0; i < length; i++) {
  80        unsigned long addr = (i >> 2) + ((i % 4) * slen);
  81        unsigned char data = inbuf[i];
  82        data = ~((data << 1) | ((data >> 7) & 1)); /* poor man's ROL */
  83        outbuf[addr] = data;
  84     }
  85
  86     /* calculate checksum */
  87     for (i=0;i<length;i++)
  88        crc += inbuf[i];
  89
  90     /* make header */
  91     memset(header, 0, sizeof header);
  92     if (headerlen == 6) {
  93         header[0] = (length >> 24) & 0xff;
  94         header[1] = (length >> 16) & 0xff;
  95         header[2] = (length >> 8) & 0xff;
  96         header[3] = length & 0xff;
  97         header[4] = (crc >> 8) & 0xff;
  98         header[5] = crc & 0xff;
  99     }
 100     else {
 101         header[0] =
 102             header[1] =
 103             header[2] =
 104             header[3] = 0xff; /* ??? */
 105
 106         header[6] = (crc >> 8) & 0xff;
 107         header[7] = crc & 0xff;
 108
 109         header[11] = 4; /* ??? */
 110
 111         header[15] = headerlen; /* really? */
 112
 113         header[20] = (length >> 24) & 0xff;
 114         header[21] = (length >> 16) & 0xff;
 115         header[22] = (length >> 8) & 0xff;
 116         header[23] = length & 0xff;
 117     }
 118
 119     /* write file */
 120     file = fopen(oname,"wb");
 121     if ( !file ) {
 122        perror(oname);
 123        return -1;
 124     }
 125     if ( !fwrite(header,headerlen,1,file) ) {
 126        perror(oname);
 127        return -1;
 128     }
 129     if ( !fwrite(outbuf,length,1,file) ) {
 130        perror(oname);
 131        return -1;
 132     }
 133     fclose(file);
 134
 135     free(inbuf);
 136     free(outbuf);
 137
 138     return 0;
 139 }