#/usr/bin/perl

use warnings;
use strict;
use CGI;

$CGI::POST_MAX = 1024 * 100;
$CGI::DISABLE_UPLOADS = 0;

my $cgi = new CGI;

my $fh = $cgi->upload('file');
my $fn = $cgi->param('file');

print $cgi->header;
print "Dateiname: ", $fn;   # Zeigt den Dateiname korrekt an!!!!

my $bin_data = 0;
for (<$fh>) {
   $bin_data .= $_;
}

my $size = length($bin_data);
print "Filesize: ", $size;     # 0 <--------------------------------

<form action="/cgi-bin/test.pl" method="post" enctype="multipart/form-data">
<input type="file" name="file">
<input type="submit">
</form>