prebuilt/windows/binpatch.c

   1 /* File: "binpatch.c", Time-stamp: <2007-04-23 22:00:14 feeley> */
   2
   3 /* Copyright (c) 2007 by Marc Feeley, All Rights Reserved. */
   4
   5 /* This is a tool for patching binary files */
   6
   7 /*---------------------------------------------------------------------------*/
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12
  13 void binpatch (char *oldstr, char *newstr, char *filename)
  14 {
  15   int oldlen = strlen (oldstr) + 1;
  16   int newlen = strlen (newstr) + 1;
  17   int step = 65536;
  18   int buflen = step + oldlen - 1;
  19   int pos;
  20   int len;
  21   char *buf;
  22   FILE *f;
  23
  24   buf = malloc (buflen);
  25   if (buf == NULL)
  26     {
  27       printf ("Could not allocate buffer\n");
  28       exit (1);
  29     }
  30
  31   f = fopen (filename, "r+b");
  32
  33   if (f == NULL)
  34     {
  35       printf ("Could not open file \"%s\"\n", filename);
  36       exit (1);
  37     }
  38
  39   fseek (f, 0, SEEK_END);
  40   len = ftell (f);
  41   if (len < 0)
  42     {
  43       fclose (f);
  44       printf ("Could not seek\n");
  45       exit (1);
  46     }
  47
  48   pos = 0;
  49
  50   while (pos < len)
  51     {
  52       int i;
  53       int n = len-pos;
  54       if (n > buflen)
  55         n = buflen;
  56       int x = fseek (f, pos, SEEK_SET);
  57       if (x < 0)
  58         {
  59           fclose (f);
  60           printf ("Could not seek\n");
  61           exit (1);
  62         }
  63       if (fread (buf, 1, n, f) != n)
  64         {
  65           fclose (f);
  66           printf ("Could not read\n");
  67           exit (1);
  68         }
  69       n = n - oldlen + 1;
  70       for (i=0; i<n; i++)
  71         if (buf[i] == oldstr[0])
  72           {
  73             int j;
  74             for (j=1; j<oldlen; j++)
  75               if (buf[i+j] != oldstr[j])
  76                 goto fail;
  77             pos = pos + i;
  78             x = fseek (f, pos, SEEK_SET);
  79             if (x < 0)
  80               {
  81                 fclose (f);
  82                 printf ("Could not seek\n");
  83                 exit (1);
  84               }
  85             if (fwrite (newstr, 1, newlen, f) != newlen)
  86               {
  87                 fclose (f);
  88                 printf ("Could not write\n");
  89                 exit (1);
  90               }
  91             fclose (f);
  92             return;
  93           fail: ;
  94           }
  95       pos += step;
  96     }
  97
  98   fclose (f);
  99   printf ("Did not find string in file \"%s\"\n", filename);
 100   exit (1);
 101 }
 102
 103 int main (int argc, char *argv[])
 104 {
 105   int i;
 106
 107   if (argc < 3)
 108     {
 109       printf ("Usage: binpatch <old-string> <new-string> <filename>...\n");
 110       exit (1);
 111     }
 112
 113   for (i=3; i<argc; i++)
 114     binpatch (argv[1], argv[2], argv[i]);
 115
 116   return 0;
 117 }
 118
 119 /*---------------------------------------------------------------------------*/