Merge lp:~clint-fewbar/ubuntu/lucid/squid/fix-upgrades-after-reload into lp:ubuntu/lucid/squid

[Clint Byrum]

This branch fixes the problem by checking to see if the problem the recent update is trying to correct has actually happened, and if so, doing a stop/start on the service using invoke-rc.d Between the stop/start, it also kills the errant pid (but only if invoke-rc.d worked, so policy is still respected).

I test this on a lucid vm in the following scenarios:

* bare bones no updates with just 'apt-get install squid' version 2.7.STABLE7-1ubuntu12
 - When preinst is run, the upstart pid and the pidfile agree, and so it exits doing nothing.

* same, but also running 'sudo reload squid', verifying that squid is not tracked by upstart anymore with 'status squid' showing stop/waiting, but 'ps auxw | grep squid' showing a running squid.
 - the job is stopped, the old squid is killed, squid is started again

* start squid, reload, kill -9, leaving stale pid file.
 - Code stops because /proc/`cat pidfile` does not exist.

* modify /etc/init/squid.conf to not use expect fork, and pass -N (basically manually putting in the new job file). This simulates the chance that a user may have applied the fix manually.
 - Code stops because the upstart pid matches the pidfile.

* stopped service before hand
 - pidfile is gone, code is not run

* removed upstart file
 - code checks for that, does not run.

[Chuck Short (zulcss)]

Looks good to me, however can you put the info in the bug report as well. ;)
chuck

review: Approve

Unmerged revisions

53. By Clint Byrum on 2011-02-15

Detect and deal with the situation where upstart has lost track of
squid. (LP: #717397)

=== modified file 'debian/changelog'
--- debian/changelog	2011-02-01 13:26:36 +0000
+++ debian/changelog	2011-02-15 00:21:42 +0000
@@ -1,3 +1,10 @@
+squid (2.7.STABLE7-1ubuntu12.2) lucid-proposed; urgency=low
+
+  * Detect and deal with the situation where upstart has lost track of
+    squid. (LP: #717397)
+
+ -- Clint Byrum <[e-mail]>  Mon, 14 Feb 2011 14:39:47 -0800
+
 squid (2.7.STABLE7-1ubuntu12.1) lucid-proposed; urgency=low
 
   * Run squid with -N and drop 'expect fork' to prevent HUP's from

=== modified file 'debian/preinst'
--- debian/preinst	2010-04-16 09:00:19 +0000
+++ debian/preinst	2011-02-15 00:21:42 +0000
@@ -52,6 +52,37 @@
 	chsh -s /bin/sh proxy
 fi
 
+# Because of this bug:
+# https://bugs.launchpad.net/bugs/573853 
+# Upstart may have lost track of squid. Correct that by using the
+# pid file to stop it and then start the job back up
+if [ "$1" = "upgrade" ] \
+  && dpkg --compare-versions "$2" lt '2.7.STABLE7-1ubuntu12.1' \
+  && [ -f "/var/run/squid.pid" ] \
+  && [ -f "/etc/init/squid.conf" ]
+then
+	SQUID_PID=`cat /var/run/squid.pid`
+	# is this still running, and actually squid
+	if [ -d "/proc/${SQUID_PID}" ] \
+	 && [ "`stat -L -c %D%i /proc/${SQUID_PID}/exe`" = "`stat -L -c %D%i /usr/sbin/squid`" ]
+	then
+		UPSTART_SQUID_PID=`initctl status squid | awk -F'process ' '/start\/running, process / { print $2 }'`
+		PIDFILE_PPID=`awk '{print $4}' /proc/$SQUID_PID/stat`
+		# If the user has disabled expect fork the pids will be the same
+		if [ "$UPSTART_SQUID_PID" != "$SQUID_PID" -a "$PIDFILE_PPID" != "$UPSTART_SQUID_PID" ]
+		then
+			# stop the job
+			if invoke-rc.d squid stop
+			then
+				# kill the pid file pid
+				kill ${SQUID_PID}
+				# start the job again
+				invoke-rc.d squid start
+			fi
+		fi
+	fi
+fi
+
 #DEBHELPER#
 
 exit 0