Description of problem:
Sometimes restarting squid leaves old processes running for a short while at the same times as new processes, and so the new processes won't start fine, forcing me to killall squid and start anew.

Version-Release number of selected component (if applicable):
3.3.x/3.4.x

How reproducible:
You have to be (un)lucky. The time to stop squid varies a lot, and the problem only happens if it takes longer than SQUID_SHUTDOWN_TIMEOUT defined in /etc/sysconfig/squid

Steps to Reproduce:
1. service squid restart

Actual results:
squid won't proxy http requests

Expected results:
squid working as usual

Additional info:
I tested this in CentOS 6.5 and using an unofficial RPM package from squid-cache.org. But I checked the squid RPM packates for Fedora and CentOS and the init.d script is the same, so the problem should affect at least RHEL6. I'm not sure this will affect Fedora 19/20 with systemd or RHEL7.

I think it's better having service squid restart failling than leaving a broken squid, so I propose the following change to /etc/init.d/squid:

------------
restart() {
	stop
	RETVAL=$?
	if [ $RETVAL -eq 0 ] ; then
		rm -rf $SQUID_PIDFILE_DIR/*
		start
	else
		echo "Failure stopping squid or stopping squid took too long. Please check before restarting."
		return 1
        fi
}
-------------

Now the restart() function, instead of blindly calling start() after stop(), it checks the return code from stop(). If stop() timeouts, it returns an error code and so restart() refuses to call start() aftewards.

This little change makes squid more robust for sysadmins who still have to use init.d scripts.

Increasing SQUID_SHUTDOWN_TIMEOUT reduces the frequence of restart failing, but doesn't guarantees success.