How to log email sent from PHP through mail() function

env.php

<?php
putenv("HTTP_HOST=".@$_SERVER["HTTP_HOST"]);
putenv("SCRIPT_NAME=".@$_SERVER["SCRIPT_NAME"]);
putenv("SCRIPT_FILENAME=".@$_SERVER["SCRIPT_FILENAME"]);
putenv("DOCUMENT_ROOT=".@$_SERVER["DOCUMENT_ROOT"]);
putenv("REMOTE_ADDR=".@$_SERVER["REMOTE_ADDR"]);
?>

sendmail-wrapper

#!/bin/sh
logger -p mail.info sendmail-wrapper.sh: \
  site=${HTTP_HOST}, \
  client=${REMOTE_ADDR}, \
  script=${SCRIPT_NAME}, \
  pwd=${PWD}, \
  uid=${UID}, \
  user=$(whoami)
/usr/sbin/sendmail -t -i $*