#!/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; }'
}

### 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

# We use dh_installinit with --no-start
#DEBHELPER#


### 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 "$1" in
  configure)
	if [ -L /etc/resolvconf/run ] ; then
		# Make sure that the symlink is canonicalizable.
		RUN_CANONICALPATH="$(readlink -f /etc/resolvconf/run || :)"
		if [ -z "$RUN_CANONICALPATH" ] ; then
			# It's not canonicalizable
			report_warn "Deleting old symlink /etc/resolvconf/run, the canonical path of whose target could not be determined"
			rm -f /etc/resolvconf/run
		fi
	fi

	# /etc/resolvconf/run is not a non-canonicalizable symlink.

	if [ -d /etc/resolvconf/run ] && ! [ -L /etc/resolvconf/run ] ; then
		# It's a directory right in /etc/resolvconf
		# Move to the new standard location.
		# The initscripts package guarantees that the new standard location is available.
		if mkdir -p /run/resolvconf/interface ; then
			F="$(echo /etc/resolvconf/run/*)"
			if [ "$F" ] && [ "$F" != '/etc/resolvconf/run/*' ] ; then
				if cp -a /etc/resolvconf/run/* /run/resolvconf ; then
					report_info "Migrated resolvconf run-time data from /etc/resolvconf/run to /run/resolvconf"
					rm -rf /etc/resolvconf/run
				fi
			else
				rm -rf /etc/resolvconf/run
			fi
			ln -nsf /run/resolvconf /etc/resolvconf/run
		else
			report_err "Could not create run-time directories; aborting"
			exit 1
		fi
	fi

	# Delete /etc/resolvconf/run if it exists but is neither a directory nor a link to one
	if [ -e /etc/resolvconf/run ] && [ ! -d /etc/resolvconf/run ] ; then
		report_warn "Deleting /etc/resolvconf/run which isn't a directory"
		rm -f /etc/resolvconf/run
	fi

	# OK, now /etc/resolvconf/run is either:
	# * nonexistent, or
	# * a dangling but canonicalizable symlink, or
	# * a symlink to a directory

	# Create subdirectory
	if [ -d /etc/resolvconf/run ] ; then
		# It's a symlink to a directory
		[ -d /etc/resolvconf/run/interface ] || mkdir /etc/resolvconf/run/interface
	elif [ -L /etc/resolvconf/run ] ; then
		# It's a dangling but canonicalizable symlink
		mkdir "$RUN_CANONICALPATH" "${RUN_CANONICALPATH}/interface"
	else
		# It's nonexistent.
		# Make directory in the standard location and link to it
		if mkdir -p /run/resolvconf/interface ; then
			ln -s /run/resolvconf /etc/resolvconf/run
		else
			report_err "Could not create run-time directories; aborting"
			exit 1
		fi
	fi

	# Link tail to original if appropriate
	if [ ! -e /etc/resolvconf/resolv.conf.d/tail ] ; 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 [ "$DEBCONF_RECONFIGURE" = 1 ] || [ "$1" = reconfigure ] ; then
		rm -f /etc/resolvconf/do-not-linkify-resolvconf
	fi
	db_get resolvconf/linkify-resolvconf
	if
		[ "$RET" = "true" ] && [ ! -e /etc/resolvconf/do-not-linkify-resolvconf ]
	then
		if is_immutable_file /etc/resolv.conf ; then
			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
		else
			if
				[ -f /etc/resolv.conf ] \
				&& {
					[ ! -L /etc/resolv.conf ] \
					|| [ ! "$(readlink /etc/resolv.conf)" = "/etc/resolvconf/run/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 /etc/resolvconf/run/resolv.conf ] ; then
					cp -a /etc/resolv.conf /etc/resolvconf/run/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 /etc/resolvconf/run/interface/original.resolvconf
			fi
			# Create the link
			ln -nsf /etc/resolvconf/run/resolv.conf /etc/resolv.conf
			# Make a record that we have created it
			echo "This is a flag file whose presence indicates that
the resolvconf package should not create a symbolic link
at /etc/resolv.conf even if the linkify-resolvconf debconf
question was answered in the affirmative.

If you remove this file then the resolvconf package may
create the symbolic link again the next time the package
is upgraded, provided the linkify-resolvconf debconf
question was answered in the affirmative.

If the administrator runs 'dpkg-reconfigure resolvconf'
then this file is removed.

This file was created by the resolvconf package's postinst
maintainer script." > /etc/resolvconf/do-not-linkify-resolvconf
		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 "$1" in
  configure)
	if [ -f /etc/resolvconf/run/packages-to-notify ] ; then
		PACKAGES_TO_NOTIFY="$(cat /etc/resolvconf/run/packages-to-notify)"
		rm -f /etc/resolvconf/run/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
