#!/bin/sh -efu
#
# Copyright (C) 2012  Dmitry V. Levin <ldv@altlinux.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with the package; if not, see <http://www.gnu.org/licenses/>.

conf_file=/etc/timezone
env_file=/etc/sysconfig/clock
dst_file=/etc/localtime
src_dir=/usr/share/zoneinfo
update_chrooted=/usr/sbin/update_chrooted
readonly conf_file env_file dst_file src_dir update_chrooted

# get configured timezone name
tz_name=
if [ -s "$conf_file" ]; then
	tz_name="$(cat -- "$conf_file")"
fi
[ -n "$tz_name" ] || if [ -s "$env_file" ]; then
	tz_name="$(ZONE= && . "$env_file" && printf %s "$ZONE")"
fi
[ -n "$tz_name" ] || exit 0
readonly tz_name

src_file="$src_dir/$tz_name"
readonly src_file
[ -f "$src_file" ] || exit 0

if cmp -s "$src_file" "$dst_file"; then
	# up to date already
	exit 0
fi

cleanup()
{
	if [ -f "$tmp_file" ]; then
		rm -f -- "$tmp_file"
	fi
	exit "$@"
}

tmp_file="$(mktemp -- "$dst_file.XXXXXX")"
readonly tmp_file
trap 'cleanup $?' EXIT
trap 'exit 143' HUP INT QUIT PIPE TERM

ln -nf -- "$src_file" "$tmp_file" 2>/dev/null ||
cp -p -- "$src_file" "$tmp_file"
mv -f -- "$tmp_file" "$dst_file"

trap - EXIT HUP INT QUIT PIPE TERM

if [ -x "$update_chrooted" ]; then
	"$update_chrooted" conf ||:
fi