#!/usr/bin/perl

use strict;
use warnings;

my $sendmail = '/usr/lib/sendmail';
my $mail_to = 'mobile@example.jp';
my $mail_from = 'mb@example.com';

{
	my ($from, $subject, $body) = &make_mail();

	&sendmail($from, $subject, $body);
}

exit 0;

sub make_mail {
	my ($from, $subject, $body);
	my $head_flag = 1;

	open (STDIN);
		while (<STDIN>) {
			if ($head_flag) {
				if (/^$/) {
					$head_flag = 0;
				} elsif ((/^From:[^<]+<([^\@>]+)\@([^>]+)>/) || (/^From: ([^\@\s]+)\@([^\s]+)/)) {
					$from = $1 . '@' . $2;
				} elsif (/^Subject:/) {
					$subject = $_;
				}
			} else {
				$body .= $_;
			}
		}
	close (STDIN);

	return $from, $subject, $body;
}

sub sendmail {
	my ($from, $subject, $body) = @_;

	open (MAIL, "| $sendmail -t") || die "Can't open $sendmail";
		print MAIL "To: $mail_to\r\n";
		print MAIL "From: $mail_from\r\n";
		print MAIL $subject;
		print MAIL "\r\n";
		print MAIL "from $from\n";
		print MAIL $body;
	close (MAIL);
}