freeldr/ntvdmpat.c

   1 /* Copyright (C) 2000 CW Sandmann (sandmann@clio.rice.edu) 1206 Braelinn, Sugar Land, TX 77479 */
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <fcntl.h>
   6 #ifdef GO32
   7 #include <unistd.h>
   8 #else
   9 #include <io.h>
  10 #endif
  11
  12 char view_only = 0;
  13 const char *client_patch_code;
  14 char buffer[20480];
  15 unsigned long search_base = 0x4c800L;
  16 int f;
  17
  18 char oldpatch[] = {0x3b, 0x05, 0xac, 0xe6 };
  19 char newpatch[] = {0x3b, 0x05, 0x58, 0x5e };
  20
  21 void patch_image(char *filename)
  22 {
  23   int i,size;
  24
  25   view_only = 0;
  26   f = open(filename, O_RDWR | O_BINARY);
  27   if (f < 0) {
  28     f = open(filename, O_RDONLY | O_BINARY);
  29     if (f < 0) {
  30       perror(filename);
  31       return;
  32     }
  33     view_only = 1;
  34   }
  35
  36   lseek(f, search_base, SEEK_SET);
  37   size = read(f, buffer, sizeof(buffer));
  38
  39   client_patch_code = NULL;
  40   for(i=0; i<size && !client_patch_code; i++)
  41     if(!memcmp(buffer+i,oldpatch,sizeof(oldpatch)))
  42       client_patch_code = (buffer+i);
  43
  44   if(!client_patch_code) {
  45     printf("Old patch string not found in %s!\n",filename);
  46   } else {
  47     lseek(f, search_base+i-1, SEEK_SET);        /* Ready to update */
  48     if(!view_only) {
  49       write(f, newpatch, sizeof(newpatch));
  50       printf("%s patched\n",filename);
  51     } else
  52       printf("%s patchable (not changed, readonly)\n",filename);
  53   }
  54   close(f);
  55   return;
  56 }
  57
  58 int main(int argc, char **argv)
  59 {
  60   int i;
  61   char filename[256];
  62   char buf1[256];
  63   char file2[256];
  64
  65   if (argc != 1) {              /* If they specify names, patch them, exit */
  66     for(i=1; i<argc; i++)
  67      patch_image(argv[i]);
  68     return 0;
  69   }
  70
  71   fprintf(stderr, "This image patches Windows 2000 NTVDM to fix nesting DPMI bug.\n");
  72
  73   strcpy(filename,getenv("SYSTEMROOT"));
  74   strcpy(file2,filename);
  75   strcat(filename,"\\system32\\ntvdm.exe");
  76   strcat(file2,"\\system32\\dllcache\\ntvdm.exe");
  77
  78   sprintf(buf1,"copy %s %s\\system32\\ntvdm.ori",filename,getenv("SYSTEMROOT"));
  79   printf("%s\n",buf1);
  80   system(buf1);
  81
  82   patch_image(file2);
  83   patch_image(filename);
  84   return 0;
  85 }