source/libs/zziplib/zziplib-0.13.62/bins/zzxorcopy.c

   1 /*
   2  *      Copyright (c) 2000,2001,2002 Guido Draheim <guidod@gmx.de>
   3  *      Use freely under the restrictions of the ZLIB License
   4  *
   5  *      show a simple program to add xor-obfuscation.
   6  *      look at the resulting file with zzxordir an zzxorcat
   7  *      Remember that xor'ing data twice will result in the original data.
   8  *      This file has no dependency with zziplib - it's freestanding.
   9  */
  10
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14 #include <ctype.h>
  15
  16 #include <zzip/_config.h> /* for ZZIP_VERSION */
  17
  18 #ifndef O_BINARY
  19 #define O_BINARY 0
  20 #endif
  21
  22 #if __STDC_VERSION__+0 < 199901
  23 #define _ssize_t int
  24 #define _size_t unsigned
  25 #else
  26 #define _ssize_t ssize_t
  27 #define _size_t size_t
  28 #endif
  29
  30 static const char usage[] =
  31 {
  32     " zzxopy [-#] <input-file> <output-file> \n"
  33     "   copies data from input-file to output-file adding simple \n"
  34     "   obfuscation by xor-ing each byte with the numeric value given. \n"
  35     "   the default xor-value is 0x55. Remember that copying data twice \n"
  36     "   with the same xor-value will result in the original file data. \n"
  37 };
  38
  39 static int xor_value;
  40
  41 static _ssize_t xor_read (FILE* f, void* p, _size_t l)
  42 {
  43     _ssize_t r = fread(p, 1, l, f);
  44     _ssize_t x; char* q; for (x=0, q=p; x < r; x++) q[x] ^= xor_value;
  45     return r;
  46 }
  47
  48 int
  49 main (int argc, char ** argv)
  50 {
  51     int argn;
  52     xor_value = 0x55;
  53
  54     if (argc <= 1 || ! strcmp (argv[1], "--help"))
  55     {
  56         printf (usage);
  57         return 0;
  58     }
  59     if (! strcmp (argv[1], "--version"))
  60     {
  61         printf (__FILE__" version "ZZIP_PACKAGE" "ZZIP_VERSION"\n");
  62         return 0;
  63     }
  64
  65     for (argn=1; argn < argc; argn++)
  66     {
  67         FILE* iF = 0;
  68         FILE* oF = 0;
  69
  70         if (argv[argn][0] == '-')
  71         {
  72             if (isdigit(argv[argn][1])) xor_value = atoi (argv[argn]+1);
  73             continue;
  74         }
  75
  76         if (argn + 1 >= argc)
  77         {
  78             printf (usage);
  79             exit (1);
  80         }
  81
  82         iF = fopen (argv[argn], "rb");
  83         if (! iF) { perror (argv[argn]); exit (2); }
  84         argn++;
  85         oF = fopen (argv[argn], "wb");
  86         if (! oF) { perror (argv[argn]); fclose(iF); exit (3); }
  87
  88         {
  89             char buf[17];
  90             _ssize_t n;
  91
  92             /* read chunks of 16 bytes into buf and print them to stdout */
  93             while (0 < (n = xor_read(iF, buf, 16)))
  94             {
  95                 buf[n] = '\0';
  96                 n = fwrite (buf, 1, n, oF);
  97                 if (n < 0) break;
  98             }
  99
 100             if (n < 0 && ferror (iF))
 101                 perror (argv[argn]);
 102         }
 103     }
 104
 105     return 0;
 106 }
 107
 108 /*
 109  * Local variables:
 110  * c-file-style: "stroustrup"
 111  * End:
 112  */