use Tie::File;
use Data::Dumper;
use strict;
use warnings;

print Dumper(foo('profile.txt'));

sub  foo {
	my (@a, %result);
	tie @a, 'Tie::File', shift;
	foreach (@a) {
		/(.*?)\s+(.*)/g;
		$result{$1} = $2 if (($1 eq 'firstname') or ($1 eq 'lastname') or ($1 eq 'middlename'));
	}
	return \%result;
}