#!/bin/sh

set -e

# summary of how this script can be called:
#        * <postinst> `configure' <most-recently-configured-version>
#        * <old-postinst> `abort-upgrade' <new version>
#        * <conflictor's-postinst> `abort-remove' `in-favour' <package>
#          <new-version>
#        * <postinst> `abort-remove'
#        * <deconfigured's-postinst> `abort-deconfigure' `in-favour'
#          <failed-install-package> <version> `removing'
#          <conflicting-package> <version>
# for details, see http://www.debian.org/doc/debian-policy/ or
# the debian-policy package

rotate_old_log_files()
{
	log_files="syslog mail.info mail.warn mail.err mail.log daemon.log \
	           kern.log auth.log user.log lpr.log cron.log debug messages"
	skipped_files=""
	dir=/var/log

	for f in $log_files; do
		if [ -e $dir/$f.0 ]; then
			rotate="yes"
			if [ -e $dir/$f.1.gz ]; then
				date0=$(stat --format=%Y $dir/$f.0)
				date1=$(stat --format=%Y $dir/$f.1.gz)
				if [ $date0 -lt $date1 ] ; then
					# .0 log file is older than .1
					skipped_files="$dir/$f.0\n$skipped_files"
					rotate="no"
				fi
			fi
			if [ "$rotate" = "yes" ] ; then
				for s in $(seq 9 -1 1) ; do
					if [ -e $dir/$f.$s.gz ]; then
						mv $dir/$f.$s.gz $dir/$f.$(($s+1)).gz
					fi
				done
				mv $dir/$f.0 $dir/$f.1
			fi
		fi
	done
	if [ -n "$skipped_files" ]; then
		printf "The following old log files were found which could not be rotated safely.\n"
		printf "\n$skipped_files\n"
		printf "Please inspect them manually and delete them, if no longer required.\n"
	fi
}


case "$1" in
    configure)
	# Rotate .0 log files when migrating from sysklogd
	if dpkg --compare-versions "$2" lt "3.18.5-1"; then
		rotate_old_log_files
	fi

	# Stop the service on upgrades before it is started again.
	# dh_installinit -r will create the start code.
	if [ -n "$2" ]; then
		if [ -x "/etc/init.d/rsyslog" ]; then
			invoke-rc.d rsyslog stop || true
		fi
	fi
    ;;

    abort-upgrade|abort-remove|abort-deconfigure)
    ;;

    *)
	echo "postinst called with unknown argument \`$1'" >&2
	exit 1
    ;;
esac


#DEBHELPER#

exit 0