mdw@git.distorted.org.uk Git - secnet/blob - test-example/random-fake-userv

   1 #!/usr/bin/perl -w
   2
   3 use strict;
   4 use POSIX;
   5
   6 open R, '/dev/urandom' or die $!;
   7
   8 system 'cat >/dev/null &';
   9
  10 sub randbytes ($) {
  11     my ($count) = @_;
  12     my $s;
  13     my $r = read R, $s, $count;
  14     die $! unless $r==$count;
  15     return $s;
  16 }
  17
  18 sub randbyteval () {
  19     my $b = randbytes 1;
  20     my ($r) = unpack 'C', $b;
  21     return $r;
  22 }
  23
  24 sub randvalue ($$) {
  25     my ($min,$maxplus1) = @_;
  26     my $b = randbyteval;
  27     return floor(($b/256.0) * ($maxplus1-$min)) + $min;
  28 }
  29
  30 for (;;) {
  31     my $lenbits = randvalue 0,14;
  32     my $len= (randbyteval << 8) | randbyteval;
  33     $len &= (1 << $lenbits)-1;
  34     my $data = randbytes $len;
  35     if (randbyteval >= 0x80) {
  36         $data =~ s{[\xc0\xdb]}{
  37             $& eq "\xc0" ? "\xcb\xdc" :
  38             $& eq "\xdb" ? "\xcb\xdd" :
  39             die
  40         }ge;
  41     }
  42     print "\xc0";
  43     print $data;
  44     STDOUT->flush;
  45 }