diff options
Diffstat (limited to 'debian/chrony-helper')
| -rwxr-xr-x | debian/chrony-helper | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/debian/chrony-helper b/debian/chrony-helper new file mode 100755 index 0000000..5099161 --- /dev/null +++ b/debian/chrony-helper @@ -0,0 +1,264 @@ +#!/bin/bash +# This script configures running chronyd to use NTP servers obtained from +# DHCP and _ntp._udp DNS SRV records. Files with servers from DHCP are managed +# externally (e.g. by a dhclient script). Files with servers from DNS SRV +# records are updated here using the dig utility. The script can also list +# and set static sources in the chronyd configuration file. +# +# Modified for Debian by Vincent Blut <vincent.debian@free.fr>. + +chronyc=/usr/bin/chronyc +chrony_conf=/etc/chrony/chrony.conf +chrony_service=chrony.service +helper_dir=/run/chrony-helper +added_servers_file=$helper_dir/added_servers + +dhclient_servers_files="/var/lib/dhcp/chrony.servers.*" +dnssrv_servers_files="$helper_dir/dnssrv@*" +dnssrv_timer_prefix=chrony-dnssrv@ + +chrony_command() { + $chronyc -n -m "$1" +} + +is_running() { + chrony_command "tracking" &> /dev/null +} + +get_servers_files() { + echo "$dhclient_servers_files" + echo "$dnssrv_servers_files" +} + +is_update_needed() { + for file in $(get_servers_files) $added_servers_file; do + [ -e "$file" ] && return 0 + done + return 1 +} + +update_daemon() { + local all_servers_with_args all_servers added_servers + + if ! is_running; then + rm -f $added_servers_file + return 0 + fi + + all_servers_with_args=$(cat $(get_servers_files) 2> /dev/null) + + all_servers=$( + echo "$all_servers_with_args" | + while read -r server serverargs; do + echo "$server" + done | sort -u) + added_servers=$( ( + cat $added_servers_file 2> /dev/null + echo "$all_servers_with_args" | + while read -r server serverargs; do + [ -z "$server" ] && continue + chrony_command "add server $server $serverargs" &> /dev/null && + echo "$server" + done) | sort -u) + + comm -23 <(echo -n "$added_servers") <(echo -n "$all_servers") | + while read -r server; do + chrony_command "delete $server" &> /dev/null + done + + added_servers=$(comm -12 <(echo -n "$added_servers") <(echo -n "$all_servers")) + + if [ -n "$added_servers" ]; then + echo "$added_servers" > $added_servers_file + else + rm -f $added_servers_file + fi +} + +get_dnssrv_servers() { + local name=$1 output + + if ! command -v dig &> /dev/null; then + echo "Missing dig (DNS lookup utility)" >&2 + return 1 + fi + + output=$(dig "$name" srv +short +ndots=2 +search 2> /dev/null) || return 0 + + echo "$output" | while read -r _ _ port target; do + server=${target%.} + [ -z "$server" ] && continue + echo "$server port $port iburst" + done +} + +check_dnssrv_name() { + local name=$1 + + if [ -z "$name" ]; then + echo "No DNS SRV name specified" >&2 + return 1 + fi + + if [ "${name:0:9}" != _ntp._udp ]; then + echo "DNS SRV name $name doesn't start with _ntp._udp" >&2 + return 1 + fi +} + +update_dnssrv_servers() { + local name=$1 + local srv_file=$helper_dir/dnssrv@$name servers + + check_dnssrv_name "$name" || return 1 + + servers=$(get_dnssrv_servers "$name") + if [ -n "$servers" ]; then + echo "$servers" > "$srv_file" + else + rm -f "$srv_file" + fi +} + +set_dnssrv_timer() { + local state=$1 name=$2 + local srv_file=$helper_dir/dnssrv@$name servers + local timer + + timer=$dnssrv_timer_prefix$(systemd-escape "$name").timer || return 1 + + check_dnssrv_name "$name" || return 1 + + if [ "$state" = enable ]; then + systemctl enable "$timer" + systemctl start "$timer" + elif [ "$state" = disable ]; then + systemctl stop "$timer" + systemctl disable "$timer" + rm -f "$srv_file" + fi +} + +list_dnssrv_timers() { + systemctl --all --full -t timer list-units | grep "^$dnssrv_timer_prefix" | \ + sed "s|^$dnssrv_timer_prefix\(.*\)\.timer.*|\1|" | + while read -r name; do + systemd-escape --unescape "$name" + done +} + +prepare_helper_dir() { + mkdir -p $helper_dir + exec 100> $helper_dir/lock + if ! flock -w 20 100; then + echo "Failed to lock $helper_dir" >&2 + return 1 + fi +} + +is_source_line() { + local pattern="^[ \t]*(server|pool|peer|refclock)[ \t]+[^ \t]+" + [[ "$1" =~ $pattern ]] +} + +list_static_sources() { + while read -r line; do + if is_source_line "$line"; then + echo "$line" + fi + done < $chrony_conf +} + +set_static_sources() { + local new_config tmp_conf + + new_config=$( + sources=$( + while read -r line; do + is_source_line "$line" && echo "$line" + done) + + while read -r line; do + if ! is_source_line "$line"; then + echo "$line" + continue + fi + + tmp_sources=$( + local removed=0 + + echo "$sources" | while read -r line2; do + if [ "$removed" -ne 0 ] || [ "$line" != "$line2" ]; then + echo "$line2" + else + removed=1 + fi + done) + + [ "$sources" == "$tmp_sources" ] && continue + sources=$tmp_sources + echo "$line" + done < $chrony_conf + + echo "$sources" + ) + + tmp_conf=${chrony_conf}.tmp + + cp -a $chrony_conf $tmp_conf && + echo "$new_config" > $tmp_conf && + mv $tmp_conf $chrony_conf || return 1 + + systemctl try-restart $chrony_service +} + +print_help() { + echo "Usage: $0 COMMAND" + echo + echo "Commands:" + echo " update-daemon" + echo " update-dnssrv-servers NAME" + echo " enable-dnssrv NAME" + echo " disable-dnssrv NAME" + echo " list-dnssrv" + echo " list-static-sources" + echo " set-static-sources < sources.list" + echo " is-running" + echo " command CHRONYC-COMMAND" +} + +case "$1" in + update-daemon|add-dhclient-servers|remove-dhclient-servers) + is_update_needed || exit 0 + prepare_helper_dir && update_daemon + ;; + update-dnssrv-servers) + prepare_helper_dir && update_dnssrv_servers "$2" && update_daemon + ;; + enable-dnssrv) + set_dnssrv_timer enable "$2" + ;; + disable-dnssrv) + set_dnssrv_timer disable "$2" && prepare_helper_dir && update_daemon + ;; + list-dnssrv) + list_dnssrv_timers + ;; + list-static-sources) + list_static_sources + ;; + set-static-sources) + set_static_sources + ;; + is-running) + is_running + ;; + command|forced-command) + chrony_command "$2" + ;; + *) + print_help + exit 2 +esac + +exit $? |