[systemd-devel] systemd unit to launch perl script/service launches the script but doesn't exit the unit

[jen142 at promessage.com]

I'm trying to launch a perl service using systemd.

The perl script is 'smtpprox'
(https://github.com/jnorell/smtpprox/blob/master/smtpprox)

The unit file I created is

	cat /etc/systemd/system/smtpprox.service
		[Unit]
		Description=smtpprox
		Requires=var-run.mount
		After=var-run.mount

		[Service]
		Type=oneshot
		KeepAfterExit=true
		PrivateTmp=false
		ExecStart=/usr/local/etc/postfix/filters/smtpprox
		127.0.0.1:10025 127.0.0.1:10026
		ExecStop=kill `pidof perl`

		[Install]
		WantedBy=multi-user.target

When I exec

	systemctl daemon-reload
	systemctl start smtpprox.service

It does start the service

	ps ax | grep smtpprox
		10835 pts/2    S+     0:00 systemctl start
		smtpprox-custom.service
		10837 ?        Ss     0:00 /usr/bin/perl -w
		/usr/local/etc/postfix/filters/smtpprox --children=4
		127.0.0.1:10025 127.0.0.1:10026
		10838 ?        S      0:00 /usr/bin/perl -w
		/usr/local/etc/postfix/filters/smtpprox --children=4
		127.0.0.1:10025 127.0.0.1:10026
		10839 ?        S      0:00 /usr/bin/perl -w
		/usr/local/etc/postfix/filters/smtpprox --children=4
		127.0.0.1:10025 127.0.0.1:10026
		10840 ?        S      0:00 /usr/bin/perl -w
		/usr/local/etc/postfix/filters/smtpprox --children=4
		127.0.0.1:10025 127.0.0.1:10026
		10841 ?        S      0:00 /usr/bin/perl -w
		/usr/local/etc/postfix/filters/smtpprox --children=4
		127.0.0.1:10025 127.0.0.1:10026

but never exits/releases at shell

	systemctl start smtpprox-custom.service
		( ... just sits here ... )

How do I get the unit to exec that script, leave the script running, and
exit the properly?

Also,  the 

	ExecStop=kill `pidof perl`

works, but kills ALL running perl scripts/jobs -- not just the smtpprox
parent/children.

What's the right way to get systemd to find/kill only the pids related
to smtpprox?

JenL