#!/usr/bin/perl -w
#
# This script generates a (binary) file of a chosen size
# filled with random bytes
#


use strict;
$|++;

use CGI::Pretty ":standard";
use CGI::Carp qw(fatalsToBrowser);
use POSIX 'floor';

## Final pass: generate file
if ( my $filename = param('file_name') and 
     my $file_size = param('file_size') and
     my $unit = param('unit') ) 
{

    open STDERR, '/dev/null';
    print header("application/octet-stream");
    exec "dd if=/dev/urandom bs=$unit count=$file_size" ;
    die "cannot exec dd: $!";
}




## Second pass: confirm and get file name
if (my $file_size = param('file_size_0') 
    and my $unit = param('unit_0') )
{
    $file_size = floor($file_size);
    my $filename = "$file_size"."$unit";
    print header, start_html("Confirm file download");
    print h1("Confirm file download");

    print start_form(-action => url()."/"."$filename".".bin");

    print checkbox(-name => 'file_name', 
                   -checked => 'checked', 
                   -value => $filename, 
                   -label => $filename.".bin");

    print hidden(-name => 'file_size',
                 -default => $file_size);
    print hidden(-name => 'unit',
                 -default => $unit eq 'KB' ? '1024' : '1M');


    print submit(-name => 'submit_button',
                 -value => 'download');
    print button(-name => 'reset_button',
                 -value => 'reset',
                 -onClick => 'history.go(-1)');

    print end_form, end_html;
    exit 0;
}

## First pass: get user input

print header, start_html("Enter a file size");
print h1("Enter the size of the file you want");
print start_form;
print textfield(-name => "file_size_0", 
                -default => 1,
                -size => 4,
                -maxlength => 4);
print radio_group(-name => "unit_0",
                  -values => ['KB', 'MB'],
                  -default => 'MB',
                  -columns => 1);
print submit;
print end_form, end_html;
exit 0;