#!/bin/sh
#
# This file is part of the resolvconf package.
#

set -e

. /usr/share/debconf/confmodule

MYNAME=resolvconf.postinst
report() { echo "${MYNAME}: $*" ; }
report_err() { report "Error: $*" >&2 ; }
report_warn() { report "Warning: $*" >&2 ; }
report_info() { report "$*" >&2 ; }

is_immutable_file() {
	[ "$1" ] || return 2
	[ -e "$1" ] || return 1
	[ ! -L "$1" ] || return 1
	local ATTR="$(lsattr "$1" 2>/dev/null || :)"
	[ "$ATTR" ] || return 1
	echo "$ATTR" | awk '$1 ~ /i/ { exit 0; }; { exit 1; }'
}

dnssec_trigger_is_installed() {
	[ -x /usr/sbin/dnssec-triggerd ]
}

case "$1" in
  configure)
	### Deal with obsolete configuration files ###
	rm -f /etc/dhcp3/dhclient-enter-hooks.d/resolvconf
	[ -f /etc/resolvconf/update.d/bind ] && mv -f /etc/resolvconf/update.d/bind /etc/resolvconf/update.d/bind.dpkg-old

	### If there are "S" runlevel symlinks in runlevels 1-5 then that is bad. Delete them. ###
	G='/etc/rc[1-5].d/S??resolvconf'
	if [ "$(echo $G)" != "$G" ] ; then
		update-rc.d resolvconf remove >/dev/null || :
	fi
	;;
esac

# Automatically added by dh_systemd_enable
# This will only remove masks created by d-s-h on package removal.
deb-systemd-helper unmask resolvconf.service >/dev/null || true

# was-enabled defaults to true, so new installations run enable.
if deb-systemd-helper --quiet was-enabled resolvconf.service; then
	# Enables the unit on first installation, creates new
	# symlinks on upgrades if the unit file has changed.
	deb-systemd-helper enable resolvconf.service >/dev/null || true
else
	# Update the statefile to add new symlinks (if any), which need to be
	# cleaned up on purge. Also remove old symlinks.
	deb-systemd-helper update-state resolvconf.service >/dev/null || true
fi
# End automatically added section
# Automatically added by dh_installinit
if [ "$1" = "configure" ] || [ "$1" = "abort-upgrade" ]; then
	if [ -x "/etc/init.d/resolvconf" ]; then
		update-rc.d resolvconf defaults >/dev/null || exit $?
	fi
fi
# End automatically added section


### Create run-time directories and linkify ###
#
# We create the run-time directories here, in the postinst, even though
# we also do so in the preinst, because
# * the system may have rebooted since the preinst ran, causing
#   everything on tmpfses to disappear;
# * multistrap doesn't run the preinst at all.
#
case "$1" in
  configure)
	# Do linkify once again on dpkg-reconfigure
	if [ "$DEBCONF_RECONFIGURE" = 1 ] || [ "$1" = reconfigure ] ; then
		rm -f /var/lib/resolvconf/linkified
	fi

	# Link tail to original if appropriate
	if [ ! -e /etc/resolvconf/resolv.conf.d/tail ] && [ ! -e /var/lib/resolvconf/linkified ] ; then
		db_get resolvconf/link-tail-to-original
		if [ "$RET" = "true" ] ; then
			ln -nsf original /etc/resolvconf/resolv.conf.d/tail
		else
			: > /etc/resolvconf/resolv.conf.d/tail
		fi
	fi

	# Linkify /etc/resolv.conf if appropriate
	if [ ! -e /var/lib/resolvconf/linkified ] ; then
		db_get resolvconf/linkify-resolvconf
		if [ "$RET" = "true" ] ; then
			if is_immutable_file /etc/resolv.conf ; then
				if dnssec_trigger_is_installed ; then
					# dnssec-trigger sets the immutability attribute. Override it.
					chattr -i /etc/resolv.conf
				else
					# Respect the admin
					report_err "Cannot replace the current /etc/resolv.conf with a symbolic link because it is immutable; to correct this problem, gain root privileges in a terminal and run 'chattr -i /etc/resolv.conf' and then 'dpkg --configure resolvconf'; aborting"
					exit 1
				fi
			else
				if
					[ -f /etc/resolv.conf ] \
					&& {
						[ ! -L /etc/resolv.conf ] \
						|| [ ! "$(readlink /etc/resolv.conf)" = "/run/resolvconf/resolv.conf" ]
					}
				then
					# Back up original file
					if [ ! -e /etc/resolvconf/resolv.conf.d/original ] ; then
						cp -a /etc/resolv.conf /etc/resolvconf/resolv.conf.d/original
					else
						cp -a /etc/resolv.conf /etc/resolv.conf.dpkg-old
					fi
					# Before creating the link, make sure that the original file is
					# at the target of the link.  /sbin/resolvconf will overwrite
					# this when it does an update, of course.
					if [ ! -e /run/resolvconf/resolv.conf ] ; then
						cp -a /etc/resolv.conf /run/resolvconf/resolv.conf
					fi
					# Add the original file to the database so that its contents
					# are included when resolvconf updates.
					# Yes, this is an ugly workaround for the problem that some
					# interface configurers haven't added a dpkg-event.d script.
					cp -a /etc/resolv.conf /run/resolvconf/interface/original.resolvconf
				fi
				# Create the link
				# The link is relative to allow for cp from outside a chroot into a chroot
				# to work without overwriting the file outside the chroot (or failing)
				ln -nsf ../run/resolvconf/resolv.conf /etc/resolv.conf
				# Make a record that we have created it
				:> /var/lib/resolvconf/linkified
			fi
		fi
	fi
	;;
  # triggered)
	# Don't do anything here
	# ;;
  # abort-upgrade)
	# Don't do anything here since we don't do anything in the prerm on upgrade or on failed-upgrade
	# ;;
  # abort-remove)
	# Don't do anything extra here since we don't deconfigure anything in the prerm on remove
	# ;;
  # abort-deconfigure)
	# Don't do anything extra here since we don't do anything in the prerm on deconfigure
	# ;;
esac

db_stop


### Notify others of our installation ###

is_installed() {
	# Same function in preinst, postinst, postrm
	[ "$1" ] || return 1
	dpkg-query -W -f='${Status}\n' "$1" 2>/dev/null | grep -siq '^[[:alpha:]]\+ [[:alpha:]]\+ installed$' >/dev/null 2>&1
}

case "$1" in
  configure)
	if [ -f /run/resolvconf/packages-to-notify ] ; then
		PACKAGES_TO_NOTIFY="$(cat /run/resolvconf/packages-to-notify)"
		rm -f /run/resolvconf/packages-to-notify
		for PKG in $PACKAGES_TO_NOTIFY ; do
			if is_installed "$PKG" ; then
				SCRPT="/usr/lib/resolvconf/dpkg-event.d/$PKG"
				if [ -x "$SCRPT" ] ; then
					"$SCRPT" install || :
				fi
			fi
		done
	fi
	;;
  # triggered)
	# Don't do anything
	# ;;
  # abort-upgrade)
	# Don't do anything here since we don't do anything in the prerm on upgrade or on failed-upgrade
	# ;;
  # abort-remove)
	# Don't do anything extra here since we don't deconfigure anything in the prerm on remove
	# ;;
  # abort-deconfigure)
	# Don't do anything extra here since we don't do anything in the prerm on deconfigure
	# ;;
esac


### (Trigger self to) enable updates ###

case "$1" in
  reconfigure)
		resolvconf --enable-updates
	;;
  configure)
	if [ "$DEBCONF_RECONFIGURE" = 1 ] ; then
		resolvconf --enable-updates
	else
		# Trigger self to enable updates later
		dpkg-trigger --no-await resolvconf-enable-updates || resolvconf --enable-updates
	fi
	;;
  triggered)
	# Runs after this and other packages have been configured
        for trggr in $2 ; do
		case "$trggr" in
		  resolvconf-enable-updates)
			resolvconf --enable-updates
			break
			;;
		esac
        done
	;;
  abort-remove)
	# We disable updates in the prerm on remove.
	# So, enable them again
	resolvconf --enable-updates
	;;
  # abort-upgrade)
	# Don't do anything here since we don't do anything in the prerm on upgrade or on failed-upgrade
	# ;;
  # abort-deconfigure)
	# Don't do anything extra here since we don't do anything in the prerm on deconfigure
	# ;;
esac

exit 0