#!/bin/sh
[ "$1" ] && {
  cat <<END
upload when email from any ESP is detected
usually run as a server with the start utility
END
  exit 2
}

revdns()
#reverse dns lookup on $1
{
  res=`nslookup $1` || return $?
  echo "$res" | tail -n1 | ( 
    read -r addr num ip name extra
    echo $name
  )
}

trigger="smtp accepted connection from"
logread -f | while read -r line; do
  ip=`expr match "$line" ".*$trigger  *\(.*\):.*"` && [ "$ip" ] &&
  fqname=`revdns "$ip"` && [ "$fqname" ] && {
    echo "==> Received email from $fqname <=="
    upload ${fqname/.*} &
  }
done