/* Generic xor handler. With no args, xors stdin against 0xFF to stdout. A single argument is a file to read xor-bytes out of. Any zero in the xor-bytes array is treated as the end; if you need to xor against a string that *includes* zeros, you're on your own. *Hobbit*, 960208 */ #include <stdio.h> #include <fcntl.h> char buf[8192]; char bytes[256]; char * py; /* do the xor, in place. Uses global ptr "py" to maintain "bytes" state */ xorb (buf, len) char * buf; int len; { register int x; register char * pb; pb = buf; x = len; while (x > 0) { *pb = (*pb ^ *py); pb++; py++; if (! *py) py = bytes; x--; } } /* xorb */ /* blah */ main (argc, argv) int argc; char ** argv; { register int x = 0; register int y; /* manually preload; xor-with-0xFF is all too common */ memset (bytes, 0, sizeof (bytes)); bytes[0] = 0xff; /* if file named in any arg, reload from that */ #ifdef O_BINARY /* DOS shit... */ x = setmode (0, O_BINARY); /* make stdin raw */ if (x < 0) { fprintf (stderr, "stdin binary setmode oops: %d\n", x); exit (1); } x = setmode (1, O_BINARY); /* make stdout raw */ if (x < 0) { fprintf (stderr, "stdout binary setmode oops: %d\n", x); exit (1); } #endif /* O_BINARY */ if (argv[1]) #ifdef O_BINARY x = open (argv[1], O_RDONLY | O_BINARY); #else x = open (argv[1], O_RDONLY); #endif if (x > 0) { read (x, bytes, 250); /* nothin' fancy here */ close (x); } py = bytes; x = 1; while (x > 0) { x = read (0, buf, sizeof (buf)); if (x <= 0) break; xorb (buf, x); y = write (1, buf, x); if (y <= 0) exit (1); } exit (0); }