extboot/signrom.c

   1 /*
   2  * Extended Boot Option ROM
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  17  *
  18  * Copyright IBM Corporation, 2007
  19  *   Authors: Anthony Liguori <aliguori@us.ibm.com>
  20  */
  21
  22 #include <stdio.h>
  23 #include <stdint.h>
  24 #include <string.h>
  25
  26 int main(int argc, char **argv)
  27 {
  28         FILE *fin, *fout;
  29         char buffer[512], oldbuffer[512];
  30         int i, size, lag = 0;
  31         uint8_t sum = 0;
  32
  33         if (argc != 3) {
  34                 printf("Usage: %s ROM OUTPUT\n", argv[0]);
  35                 return 1;
  36         }
  37
  38         fin = fopen(argv[1], "rb");
  39         fout = fopen(argv[2], "wb");
  40
  41         if (fin == NULL || fout == NULL) {
  42                 fprintf(stderr, "Could not open input/output files\n");
  43                 return 1;
  44         }
  45
  46         do {
  47                 size = fread(buffer, 512, 1, fin);
  48                 if (size == 1) {
  49                         for (i = 0; i < 512; i++)
  50                                 sum += buffer[i];
  51
  52                         if (lag) {
  53                                 if (fwrite(oldbuffer, 512, 1, fout) != 1) {
  54                                         fprintf(stderr, "Write failed\n");
  55                                         return 1;
  56                                 }
  57                         }
  58                         lag = 1;
  59                         memcpy(oldbuffer, buffer, 512);
  60                 }
  61         } while (size == 1);
  62
  63         if (size != 0) {
  64                 fprintf(stderr, "Failed to read from input file\n");
  65                 return 1;
  66         }
  67
  68         oldbuffer[511] = -sum;
  69
  70         if (fwrite(oldbuffer, 512, 1, fout) != 1) {
  71                 fprintf(stderr, "Failed to write to output file\n");
  72                 return 1;
  73         }
  74
  75         fclose(fin);
  76         fclose(fout);
  77
  78         return 0;
  79 }