#!/bin/sh -e

if dpkg --compare-versions "$2" lt-nl 0.6.0; then
# We're upgrading from a version of Upstart that doesn't use
# D-Bus for its IPC. We have to tell it to re-exec into one
# that does. It'll lose all state, but we didn't keep much
# in those days.
telinit u
elif ! ischroot; then
# Do not honour re-exec when requested from within a
# chroot since:
#
# (a) The version of Upstart outside might not support it.
# (b) An isolated environment such as a chroot should
# not be able to modify its containing environment.
#
# A sufficiently new Upstart will actually handle a re-exec
# request coming from telinit within a chroot correctly,
# but it's simple enough to perform the check here and save
# Upstart the effort.

# Query running version of Upstart, but only when we know
# that initctl will work.
#
# The calculated version string may be the null string if
# Upstart is not running (where for example an alternative
# init is running outside a chroot environment) or if the
# query failed for some reason. However, the version check
# below handles a null version string correctly.
UPSTART_VERSION_RUNNING=$(initctl version 2>/dev/null |\
awk '{print $3}'|tr -d ')' || :)

if dpkg --compare-versions "$UPSTART_VERSION_RUNNING" ge 1.9 || [ "$UPSTART_VERSION_RUNNING" = 1.8-ubuntu-full-serialization ]; then
# We are not running inside a chroot and the running version
# of Upstart supports lossless stateful re-exec, so we can
# restart immediately.
#
# XXX: Note that the check on the running version must
# remain *indefinitely* since it's the only safe way to
# know if stateful re-exec is supported: simply checking
# packaged version numbers is not sufficient since
# the package could be upgraded multiple times without a
# reboot.
telinit u || :
elif [ "$UPSTART_JOB" = "cloud-config" ]; then
# If upgraded by cloud-init, do not perform partial
# stateful re-exec, as cloud-init instance will fail
# to initialise.
touch /var/run/init.upgraded || :
[ -x /usr/share/update-notifier/notify-reboot-required ] && \
/usr/share/update-notifier/notify-reboot-required || true

elif dpkg --compare-versions "$UPSTART_VERSION_RUNNING" ge 1.6.1; then
# Otherwise, perform partial stateful re-exec and
# request a reboot.
telinit u || :
[ -x /usr/share/update-notifier/notify-reboot-required ] && \
/usr/share/update-notifier/notify-reboot-required || true
else
# Before we shutdown or reboot, we need to re-exec so that we
# can safely remount the root filesystem; we can't just do that
# here because we lose state.
touch /var/run/init.upgraded || :
fi
fi

# Automatically added by dh_installdeb
dpkg-maintscript-helper rm_conffile /etc/init/dbus-reconnect.conf 0.6.3-7 -- "$@"
# End automatically added section
# Automatically added by dh_installdeb
dpkg-maintscript-helper rm_conffile /etc/init/upstart-dbus-bridge.conf 1.9.1-0ubuntu4 -- "$@"
# End automatically added section