randomize

#!/usr/bin/perl

use strict;
use warnings;
use IO::File;

$|=1;

my $file;

sub randomString(){
        my $fetch=(int(rand(512))+512)*16384;
        my $data='';
        my $packet;
        my $fh=new IO::File('/dev/urandom','r')
                || die("Unable to open /dev/urandom: $!\n");
        binmode($fh);
        while(length($data) < $fetch){
                printf("\rGenerating %d bytes urandom string... %d%%",$fetch,(length($data)*100/$fetch));
                read($fh,$packet,8192);
                $data.=$packet;
        }
        $fh->close();
        printf("\rGenerating %d bytes urandom string... done\n",$fetch);
        return($data);
}

sub fillDisk($){
        my $string=shift;
        my $written=0;
        my $size=length($string);
        my $started=time;
        my $mbytes;
        $SIG{TERM}=$SIG{INT}=sub{
                        print("\n");
                        removeFile();
                        exit(1);
                };
        my $fh=new IO::File($file,'w')
                || die("Unable to open $file: $!\n");
        binmode($fh);
        while(print($fh $string)){
                $written+=$size;
                $mbytes=$written/1048576;
                printf("\rWriting growing file to disk... %d MB (%d MB/s)   ",$mbytes,($mbytes/((time-$started)||1)));
        }
        $fh->close();
        print("\n");
}

sub syncDisk(){
        print('Writing cached data to disk... ');
        system('/bin/sync');
        print("done\n");
}

sub removeFile(){
        print('Removing the growing file from disk... ');
        unlink($file);
        system('/bin/sync');
        print("done\n");
}

sub showUsage(){
print(<<__EOF);
This programm will generate a urandom string of 8 to 16 MBytes,
repeatedly write this into the given file until writing becomes impossible
and remove the file from disk.

The given file must NOT exist!

Usage: $0 <filename>

__EOF
        exit(1);
}

sub main(){
        $file=$ARGV[0];
        print("Randomize Free Space, (C)2006 Veit Wahlich <cru at zodia dot de>\n\n");
        unless(defined($file) && $file=~/^[^\-]/ && not(-e $file)){
                showUsage();
        }
        fillDisk(randomString());
        syncDisk();
        removeFile();
        exit(0);
}

main();
1;