#!/usr/bin/perl -w
#
##########################################################################
#                                                                        #
# sendmail, a perl-replacement for the original, it just collects the    #
# data, and sends them to the specified eMailserver.                     #
# diposition to enable mailing for servers, who don't have a dinosaur :) #
#                                                                        #
# No relay by smtp possible with this script!                            #
# No commands the original knows are recognized!                         #
#                                                                        #
# put it to /usr/lib/sendmail, the standard place for the original or    #
# the place it is expected to satisfy other applications.                #
#                                                                        #
##########################################################################


use Net::SMTP;                          # module which does the mailing
                                        # has to be installed

use strict;

my @textdata = <STDIN>;                 # fetch incoming data

undef my $hclf;                         # variables initialised for use strict
my $textdata;                           # other mys are spread over the script
my $loop;
my @loop;
undef my $mail_to;
undef my $mail_subject;
undef my $mail_from;
my $mail_text;

############################
#                          #
# user setting start here: #

$mailhost = "host.domain.where";        # the mailserver, which delivers mail

$maileruser = "username\@domain.where"; # the user, who is allowed to use the mailserver
                                        # the user, who gets errormessages, too
#$hclf = "/tmp/sendmail.log"            # file, where to pipe all mailcontent at.
                                        # use only for debugging!
                                        # if used by cgi, webserver's user needs
                                        # rights to write there (apache).

#my $mdebug = "1";                      # debug the module on stdout, default value is "1"
                                        # higher values are possible but not useful
my $mdebug = "0";                       # don't debug the module on stdout

# user settings stop here! #
#                          #
############################

if ($hclf) {
    open (GUN,">>$hclf") || die "cant write to $hclf";
    print GUN scalar localtime();
   }

undef my $counter;                      # init helpers, just to be safe
undef my $body;

foreach $textdata (@textdata) {
 print GUN $textdata if $hclf;
 if ($counter < 3) {
  $loop[$counter] = $textdata;            # collect "To:", "From:" and "Subject:"
                                        # "To:" and "From:" are required,
                                        # "Subject:" is optional, see later
 }
 else {
  $body = $body . $textdata;            # collect bodytext
 }

 $counter++;
}

print GUN "\n###################################\n" if $hclf;

if ($hclf) {
    close (GUN) || die "cant close $hclf";
   }

undef my $count;

for my $i (0 .. 2) {
 if ($loop[$i] =~ /to:\s*([\w\W]*)/i) { # case insensitive is required here!
     $mail_to      = $1;             # to match all clients using this :)
     $count++;
    }
 if ($loop[$i] =~ /subject:\s*([\w\W]*)/i) {
     $mail_subject = $1;
     $count++;
    }
 if ($loop[$i] =~ /from:\s*([\w\W]*)/i) {
     $mail_from    = $1;
     $count++;
    }
}

if (                                    # cases, if mail is undeliverable
    (! $mail_to) or                     # if so, alarm defined $maileruser
    (! $mail_from)
   ) {
 my $whereat      = `/bin/uname -n`;
 chomp $whereat;
 $mail_to      = $maileruser;
 $mail_from    = "perlsendmail <$maileruser>";
 $mail_subject = "perlsendmail has found an error at $whereat!";
 $mail_text    = "0: $loop[0]1: $loop[1]2: $loop[2]$body";
}

else {                                  # if ok, init remaining vars
 if ($count lt 3) {
  $mail_text   = $loop[2]
 }
 $mail_text    = $mail_text . $body;
 $mail_subject = "\n" if (! $mail_subject); # catch empty subjects even not given

                                        # any other header informatin should
                                        # be at the top of the $body

}

my $time = "Date: " . localtime();
chomp $mail_from;
chomp $mail_to;
chomp $mail_subject;

my $smtp = Net::SMTP->new("$mailhost",
                           Debug   => $mdebug,
                      );
$smtp->mail("$mail_from");
$smtp->to("$mail_to");
$smtp->data();
$smtp->datasend("From: $mail_from
$time
To: $mail_to
Subject: $mail_subject
$mail_text
");

$smtp->quit;
exit;                                   # bye-bye, baby :)