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Diffstat (limited to 'scripts/update-leap/update-leap')
| -rw-r--r-- | scripts/update-leap/update-leap | 434 |
1 files changed, 434 insertions, 0 deletions
diff --git a/scripts/update-leap/update-leap b/scripts/update-leap/update-leap new file mode 100644 index 0000000..2dab4ec --- /dev/null +++ b/scripts/update-leap/update-leap @@ -0,0 +1,434 @@ +#!/bin/bash + +# Copyright (C) 2014 Timothe Litt litt at acm dot org + +# This script may be freely copied, used and modified providing that +# this notice and the copyright statement are included in all copies +# and derivative works. No warranty is offered, and use is entirely at +# your own risk. Bugfixes and improvements would be appreciated by the +# author. + +VERSION="1.003" + +# leap-seconds file manager/updater + +# Depends on: +# wget sed, tr, shasum, logger + +# ########## Default configuration ########## +# +# Where to get the file +LEAPSRC="ftp://time.nist.gov/pub/leap-seconds.list" + +# How many times to try to download new file +MAXTRIES=6 +INTERVAL=10 + +# Where to find ntp config file +NTPCONF=/etc/ntp.conf + +# How long before expiration to get updated file +PREFETCH="60 days" + +# How to restart NTP - older NTP: service ntpd? try-restart | condrestart +# Recent NTP checks for new file daily, so there's nothing to do +RESTART= + +# Where to put temporary copy before it's validated +TMPFILE="/tmp/leap-seconds.$$.tmp" + +# Syslog facility +LOGFAC=daemon +# ########################################### + +# Places to look for commands. Allows for CRON having path to +# old utilities on embedded systems + +PATHLIST="/opt/sbin:/opt/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:" + +REQUIREDCMDS=" wget logger tr sed shasum" + +SELF="`basename $0`" + +function displayHelp { + cat <<EOF +Usage: $SELF [options] [leapfile] + +Verifies and if necessary, updates leap-second definition file + +All arguments are optional: Default (or current value) shown: + -s Specify the URL of the master copy to download + $LEAPSRC + -4 Use only IPv4 + -6 Use only IPv6 + -p 4|6 + Prefer IPv4 or IPv6 (as specified) addresses, but use either + -d Specify the filename on the local system + $LEAPFILE + -e Specify how long before expiration the file is to be refreshed + Units are required, e.g. "-e 60 days" Note that larger values + imply more frequent refreshes. + "$PREFETCH" + -f Specify location of ntp.conf (used to make sure leapfile directive is + present and to default leapfile) + $NTPCONF + -F Force update even if current file is OK and not close to expiring. + -c Command to restart NTP after installing a new file + <none> - ntpd checks file daily + -r Specify number of times to retry on get failure + $MAXTRIES + -i Specify number of minutes between retries + $INTERVAL + -l Use syslog for output (Implied if CRONJOB is set) + -L Don't use syslog for output + -P Specify the syslog facility for logging + $LOGFAC + -t Name of temporary file used in validation + $TMPFILE + -q Only report errors to stdout + -v Verbose output + -z Specify path for utilities + $PATHLIST + -Z Only use system path + +$SELF will validate the file currently on the local system + +Ordinarily, the file is found using the "leapfile" directive in $NTPCONF. +However, an alternate location can be specified on the command line. + +If the file does not exist, is not valid, has expired, or is expiring soon, +a new copy will be downloaded. If the new copy validates, it is installed and +NTP is (optionally) restarted. + +If the current file is acceptable, no download or restart occurs. + +-c can also be used to invoke another script to perform administrative +functions, e.g. to copy the file to other local systems. + +This can be run as a cron job. As the file is rarely updated, and leap +seconds are announced at least one month in advance (usually longer), it +need not be run more frequently than about once every three weeks. + +For cron-friendly behavior, define CRONJOB=1 in the crontab. + +This script depends on$REQUIREDCMDS + +Version $VERSION +EOF + return 0 +} + +# Default: Use syslog for logging if running under cron + +SYSLOG="$CRONJOB" + +if [ "$1" = "--help" ]; then + displayHelp + exit 0 +fi + +# Parse options + +while getopts 46p:P:s:e:f:Fc:r:i:lLt:hqvz:Z opt; do + case $opt in + 4) + PROTO="-4" + ;; + 6) + PROTO="-6" + ;; + p) + if [ "$OPTARG" = '4' -o "$OPTARG" = '6' ]; then + PREFER="--prefer-family=IPv$OPTARG" + else + echo "Invalid -p $OPTARG" >&2 + exit 1; + fi + ;; + P) + LOGFAC="$OPTARG" + ;; + s) + LEAPSRC="$OPTARG" + ;; + e) + PREFETCH="$OPTARG" + ;; + f) + NTPCONF="$OPTARG" + ;; + F) + FORCE="Y" + ;; + c) + RESTART="$OPTARG" + ;; + r) + MAXTRIES="$OPTARG" + ;; + i) + INTERVAL="$OPTARG" + ;; + t) + TMPFILE="$OPTARG" + ;; + l) + SYSLOG="y" + ;; + L) + SYSLOG= + ;; + h) + displayHelp + exit 0 + ;; + q) + QUIET="Y" + ;; + v) + VERBOSE="Y" + ;; + z) + PATHLIST="$OPTARG:" + ;; + Z) + PATHLIST= + ;; + *) + echo "$SELF -h for usage" >&2 + exit 1 + ;; + esac +done +shift $((OPTIND-1)) + +export PATH="$PATHLIST$PATH" + +# Add to path to deal with embedded systems +# +for P in $REQUIREDCMDS ; do + if >/dev/null 2>&1 which "$P" ; then + continue + fi + [ "$P" = "logger" ] && continue + echo "FATAL: missing $P command, please install" + exit 1 +done + +# Handle logging + +if ! LOGGER="`2>/dev/null which logger`" ; then + LOGGER= +fi + +function log { + # "priority" "message" + # + # Stdout unless syslog specified or logger isn't available + # + if [ -z "$SYSLOG" -o -z "$LOGGER" ]; then + if [ -n "$QUIET" -a \( "$1" = "info" -o "$1" = "notice" -o "$1" = "debug" \) ]; then + return 0 + fi + echo "`echo \"$1\" | tr a-z A-Z`: $2" + return 0 + fi + + # Also log to stdout if cron job && notice or higher + local S + if [ -n "$CRONJOB" -a \( "$1" != "info" \) -a \( "$1" != "debug" \) ] || [ -n "$VERBOSE" ]; then + S="-s" + fi + $LOGGER $S -t "$SELF[$$]" -p "$LOGFAC.$1" "$2" +} + +# Verify interval +INTERVAL=$(( $INTERVAL *1 )) + +# Validate a leap-seconds file checksum +# +# File format: (full description in files) +# # marks comments, except: +# #$ number : the NTP date of the last update +# #@ number : the NTP date that the file expires +# Date (seconds since 1900) leaps : leaps is the # of seconds to add for times >= Date +# Date lines have comments. +# #h hex hex hex hex hex is the SHA-1 checksum of the data & dates, excluding whitespace w/o leading zeroes + +function verifySHA { + + if [ ! -f "$1" ]; then + return 1 + fi + + # Remove comments, except those that are markers for last update, expires and hash + + local RAW="`sed $1 -e'/^\\([0-9]\\|#[\$@h]\)/!d' -e'/^#[\$@h]/!s/#.*\$//g'`" + + # Extract just the data, removing all whitespace + + local DATA="`echo \"$RAW\" | sed -e'/^#h/d' -e's/^#[\$@]//g' | tr -d '[:space:]'`" + + # Compute the SHA hash of the data, removing the marker and filename + # Computed in binary mode, which shouldn't matter since whitespace has been removed + # shasum comes in several flavors; a portable one is available in Perl (with Digest::SHA) + + local DSHA="`echo -n \"$DATA\" | shasum | sed -e's/[? *].*$//'`" + + # Extract the file's hash. Restore any leading zeroes in hash segments. + + # The sed [] includes a tab (\t) and space; #h is followed by a tab and space + local FSHA="`echo \"$RAW\" | sed -e'/^#h/!d' -e's/^#h//' -e's/[ ] */ 0x/g'`" + FSHA=`printf '%08x%08x%08x%08x%08x' $FSHA` + + if [ -n "$FSHA" -a \( "$FSHA" = "$DSHA" \) ]; then + if [ -n "$2" ]; then + log "info" "Checksum of $1 validated" + fi + else + log "error" "Checksum of $1 is invalid:" + [ -z "$FSHA" ] && FSHA="(no checksum record found in file)" + log "error" "EXPECTED: $FSHA" + log "error" "COMPUTED: $DSHA" + return 1 + fi + + # Check the expiration date, converting NTP epoch to Unix epoch used by date + + EXPIRES="`echo \"$RAW\" | sed -e'/^#@/!d' -e's/^#@//' | tr -d '[:space:]'`" + EXPIRES="$(($EXPIRES - 2208988800 ))" + + if [ $EXPIRES -lt `date -u +%s` ]; then + log "notice" "File expired on `date -u -d \"Jan 1, 1970 00:00:00 +0000 + $EXPIRES seconds\"`" + return 2 + fi + +} + +# Verify ntp.conf + +if ! [ -f "$NTPCONF" ]; then + log "critical" "Missing ntp configuration $NTPCONF" + exit 1 +fi + +# Parse ntp.conf for leapfile directive + +LEAPFILE="`sed $NTPCONF -e'/^ *leapfile *.*$/!d' -e's/^ *leapfile *//'`" +if [ -z "$LEAPFILE" ]; then + log "error" "$NTPCONF does not specify a leapfile" +fi + +# Allow placing the file someplace else - testing + +if [ -n "$1" ]; then + if [ "$1" != "$LEAPFILE" ]; then + log "notice" "Requested install to $1, but $NTPCONF specifies $LEAPFILE" + fi + LEAPFILE="$1" +fi + +# Verify the current file +# If it is missing, doesn't validate or expired +# Or is expiring soon +# Download a new one + +if [ -n "$FORCE" ] || ! verifySHA $LEAPFILE "$VERBOSE" || [ $EXPIRES -lt `date -d "NOW + $PREFETCH" +%s` ] ; then + TRY=0 + while true; do + TRY=$(( $TRY + 1 )) + if [ -n "$VERBOSE" ]; then + log "info" "Attempting download from $LEAPSRC, try $TRY.." + fi + if wget $PROTO $PREFER -o ${TMPFILE}.log $LEAPSRC -O $TMPFILE ; then + log "info" "Download of $LEAPSRC succeeded" + if [ -n "$VERBOSE" ]; then + cat ${TMPFILE}.log + fi + + if ! verifySHA $TMPFILE "$VERBOSE" ; then + # There is no point in retrying, as the file on the server is almost + # certainly corrupt. + + log "warning" "Downloaded file $TMPFILE rejected -- saved for diagnosis" + cat ${TMPFILE}.log + rm -f ${TMPFILE}.log + exit 1 + fi + rm -f ${TMPFILE}.log + + # Set correct permissions on temporary file + + REFFILE="$LEAPFILE" + if [ ! -f $LEAPFILE ]; then + log "notice" "$LEAPFILE was missing, creating new copy - check permissions" + touch $LEAPFILE + # Can't copy permissions from old file, copy from NTPCONF instead + REFFILE="$NTPCONF" + fi + chmod --reference $REFFILE $TMPFILE + chown --reference $REFFILE $TMPFILE + ( which selinuxenabled && selinuxenabled && which chcon ) >/dev/null 2>&1 + if [ $? == 0 ] ; then + chcon --reference $REFFILE $TMPFILE + fi + + # Replace current file with validated new one + + if mv -f $TMPFILE $LEAPFILE ; then + log "notice" "Installed new $LEAPFILE from $LEAPSRC" + else + log "error" "Install $TMPFILE => $LEAPFILE failed -- saved for diagnosis" + exit 1 + fi + + # Restart NTP (or whatever else is specified) + + if [ -n "$RESTART" ]; then + if [ -n "$VERBOSE" ]; then + log "info" "Attempting restart action: $RESTART" + fi + R="$( 2>&1 $RESTART )" + if [ $? -eq 0 ]; then + log "notice" "Restart action succeeded" + if [ -n "$VERBOSE" -a -n "$R" ]; then + log "info" "$R" + fi + else + log "error" "Restart action failed" + if [ -n "$R" ]; then + log "error" "$R" + fi + exit 2 + fi + fi + exit 0 + fi + + # Failed to download. See about trying again + + rm -f $TMPFILE + if [ $TRY -ge $MAXTRIES ]; then + break; + fi + if [ -n "$VERBOSE" ]; then + cat ${TMPFILE}.log + log "info" "Waiting $INTERVAL minutes before retrying..." + fi + sleep $(( $INTERVAL * 60)) + done + + # Failed and out of retries + + log "warning" "Download from $LEAPSRC failed after $TRY attempts" + if [ -f ${TMPFILE}.log ]; then + cat ${TMPFILE}.log + rm -f ${TMPFILE}.log $TMPFILE + fi + exit 1 +fi +log "info" "Not time to replace $LEAPFILE" + +exit 0 + +# EOF
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