check_domain.sh

#!/bin/bash
# Nagios plugin for checking a domain name expiration date
#
# Copyright (c) 2005 Tomàs Núñez Lirola <tnunez@criptos.com> (Original Author),
# Copyright (c) 2009-2016 Elan Ruusamäe <glen@pld-linux.org> (Current Maintainer)
#
# Licensed under GPL v2 License
# URL: https://github.com/glensc/nagios-plugin-check_domain

# License: GPL v2
# Homepage: https://github.com/glensc/nagios-plugin-check_domain
# Changes: https://github.com/glensc/nagios-plugin-check_domain/commits/master
# Nagios Exchange Entry: http://exchange.nagios.org/directory/Plugins/Internet-Domains-and-WHOIS/check_domain/details
# Reporting Bugs: https://github.com/glensc/nagios-plugin-check_domain/issues/new

# fail on first error, do not continue
set -e

PROGRAM=${0##*/}
VERSION=1.6.0

STATE_OK=0
STATE_WARNING=1
STATE_CRITICAL=2
STATE_UNKNOWN=3

WHOIS_CALLS=0

die() {
    local rc="$1"
    local msg="$2"
    echo "$msg"

    if [ "$rc" = 0 ]; then
        # remove outfile if not caching
        [ -z "$cache_dir" ] && rm -f "$outfile"
    else
        # always remove output even if caching to force re-check in case on errors
        rm -f "$outfile"
    fi

    exit "$rc"
}

# return true if argument is numeric
# http://stackoverflow.com/a/3951175/2314626
is_numeric() {
    case "$1" in
    ''|*[!0-9]*)
        return 1
        ;;
    esac
    return 0
}

version() {
    echo "check_domain - v$VERSION"
}

usage() {
    echo "Usage: $PROGRAM -h | -d <domain> [-c <critical>] [-w <warning>] [-P <path_to_whois>] [-s <server>]"
}

fullusage() {
    cat <<EOF
check_domain - v$VERSION
Copyright (c) 2005 Tomàs Núñez Lirola <tnunez@criptos.com> (Original Author),
Copyright (c) 2009-2017 Elan Ruusamäe <glen@pld-linux.org> (Current Maintainer)
Under GPL v2 License

This plugin checks the expiration date of a domain name.

Usage: $PROGRAM -h | -d <domain> [-c <critical>] [-w <warning>] [-P <path_to_whois>] [-s <server>]
NOTE: -d must be specified

Options:
-h, --help
     Print detailed help
-V, --version
     Print version information
-d, --domain
     Domain name to check
-w, --warning
     Response time to result in warning status (days)
-c, --critical
     Response time to result in critical status (days)
-P, --path
     Path to whois binary
-s, --server
     Specific Whois server for domain name check
-a, --cache-age
     How many days should each WHOIS lookup be cached for (default 0). Requires cache dir.
-C, --cache-dir
     Directory where to cache lookups

This plugin will use whois service to get the expiration date for the domain name.
Example:
     $PROGRAM -d domain.tld -w 30 -c 10

EOF
}

set_defaults() {
    # Default values (days):
    critical=7
    warning=30

    cache_age=0
    cache_dir=

    awk=${AWK:-awk}
}

# Parse command line arguments
parse_arguments() {
    local args
    args=$(getopt -o hVd:w:c:P:s:a:C: --long help,version,domain:,warning:,critical:,path:,server:,cache-age:,cache-dir: -u -n "$PROGRAM" -- "$@")
    eval set -- "$args"

    while :; do
        case "$1" in
        -c|--critical)
            shift
            critical=$1
        ;;
        -w|--warning)
            shift
            warning=$1
        ;;
        -d|--domain)
            shift
            domain=$(echo $1 | awk -F/ '{n=split($1, a, "."); printf("%s.%s\n", a[n-1], a[n])}')
        ;;
        -P|--path)
            shift
            whoispath=$1
        ;;
        -s|--server)
            shift
            server=$1
        ;;
        -V|--version)
            version
            exit
        ;;
        -a|--cache-age)
            shift
            cache_age=$1
        ;;
        -C|--cache-dir)
            shift
            cache_dir=$1
        ;;
        -h|--help)
            fullusage
            exit
        ;;
        --)
            shift
            break
        ;;
        *)
            die "$STATE_UNKNOWN" "Internal error!"
        ;;
        esac
        shift
    done

    if [ -z "$domain" ]; then
        die "$STATE_UNKNOWN" "UNKNOWN - There is no domain name to check"
    fi

    # validate cache args
    if [ -n "$cache_dir" ] && [ ! -d "$cache_dir" ]; then
        die "$STATE_UNKNOWN" "Cache dir: '$cache_dir' does not exist"
    fi
    if [ -n "$cache_age" ] && ! is_numeric "$cache_age"; then
        die "$STATE_UNKNOWN" "Cache age is not numeric: '$cache_age'"
    fi
    if [ -n "$cache_dir" ] && [ "$cache_age" -le 0 ]; then
        die "$STATE_UNKNOWN" "Cache dir set, but age not"
    fi
}

# create tempfile. as secure as possible
# tempfile name is returned to stdout
tempfile() {
    mktemp --tmpdir -t check_domainXXXXXX 2>/dev/null || echo "${TMPDIR:-/tmp}/check_domain.$RANDOM.$$"
}

# Looking for whois binary
setup_whois() {
    if [ -n "$whoispath" ]; then
        if [ -x "$whoispath" ]; then
            whois=$whoispath
        elif [ -x "$whoispath/whois" ]; then
            whois=$whoispath/whois
        fi
        [ -n "$whois" ] || die "$STATE_UNKNOWN" "UNKNOWN - Unable to find whois binary, you specified an incorrect path"
    else
        type whois > /dev/null 2>&1 || die "$STATE_UNKNOWN" "UNKNOWN - Unable to find whois binary in your path. Is it installed? Please specify path."
        whois=whois
    fi
}

# Run whois(1)
run_whois() {
    local error

    setup_whois

    $whois ${server:+-h $server} "$domain" > "$outfile" 2>&1 && error=$? || error=$?
    WHOIS_CALLS=$((WHOIS_CALLS+1))

    [ -s "$outfile" ] || die "$STATE_UNKNOWN" "UNKNOWN - Domain $domain doesn't exist or no WHOIS server available."

    if grep -q -e "No match for" -e "NOT FOUND" -e "NO DOMAIN" "$outfile"; then
        die "$STATE_UNKNOWN" "UNKNOWN - Domain $domain doesn't exist."
    fi

    # check for common errors
    if grep -q -e "Query rate limit exceeded. Reduced information." -e "WHOIS LIMIT EXCEEDED" "$outfile"; then
        die "$STATE_UNKNOWN" "UNKNOWN - Rate limited WHOIS response"
    fi
    if grep -q -e "fgets: Connection reset by peer" "$outfile"; then
        error=0
    fi

    # We need to try up to 10 times because whois can be unreliable
    if [ $error -ne 0 ] ; then
        if [ $WHOIS_CALLS -gt 10 ]; then
            die "$STATE_UNKNOWN" "UNKNOWN - WHOIS exited with error $error."
        fi
        sleep 1
        run_whois
    fi
}

# Calculate days until expiration from whois output
get_expiration() {
    local outfile=$1

    # shellcheck disable=SC2016
    $awk '
    BEGIN {
        HH_MM_DD = "[0-9][0-9]:[0-9][0-9]:[0-9][0-9]"
        YYYY = "[0-9][0-9][0-9][0-9]"
        DD = "[0-9][0-9]"
        MON = "[A-Za-z][a-z][a-z]"
        DATE_DD_MM_YYYY_DOT = "[0-9][0-9]\\.[0-9][0-9]\\.[0-9][0-9][0-9][0-9]"
        DATE_DD_MON_YYYY = "[0-9][0-9]-[A-Za-z][a-z][a-z]-[0-9][0-9][0-9][0-9]"
        DATE_ISO_FULL = "[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]T"
        DATE_ISO_LIKE = "[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9] "
        DATE_YYYY_MM_DD_DASH = "[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]"
        DATE_YYYY_MM_DD_DOT = "[0-9][0-9][0-9][0-9]\\.[0-9][0-9]\\.[0-9][0-9]"
        DATE_YYYY_MM_DD_SLASH = "[0-9][0-9][0-9][0-9]/[0-9][0-9]/[0-9][0-9]"
        DATE_DD_MM_YYYY_SLASH = "[0-9][0-9]/[0-9][0-9]/[0-9][0-9][0-9][0-9]"
        DATE_YYYY_MM_DD_NIL = "[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]"
        # 2015-10-03 13:36:48
        DATE_YYYY_MM_DD_DASH_HH_MM_SS = DATE_YYYY_MM_DD_DASH " " HH_MM_DD
        # 15.05.2016 13:36:48
        DATE_DD_MM_YYYY_DOT_HH_MM_SS = DATE_DD_MM_YYYY_DOT " " HH_MM_DD

        # Wed Mar 02 23:59:59 GMT 2016
        DATE_DAY_MON_DD_HHMMSS_TZ_YYYY = "[A-Z][a-z][a-z] [A-Z][a-z][a-z] [0-9][0-9] " HH_MM_DD " GMT " YYYY
        # 25-Apr-2018 16:00:50
        DATE_DD_MON_YYYY_HHMMSS = "[0-9][0-9]-" MON "-" YYYY " " HH_MM_DD
        # 02-May-2018 16:12:25 UTC
        DATE_DD_MON_YYYY_HHMMSS_TZ = "[0-9][0-9]-" MON "-" YYYY " " HH_MM_DD " UTC"
        # 2016.01.14 18:47:31
        DATE_YYYYMMDD_HHMMSS = DATE_YYYY_MM_DD_DOT " " HH_MM_DD
        # 21/05/2017 00:00:00 EEST
        DATE_DD_MM_YYYY_SLASH_HHMMSS_TZ = DATE_DD_MM_YYYY_SLASH " " HH_MM_DD " [A-Z]+"
        # 14 Jan 2016 22:40:29 UTC
        DATE_DD_MON_YYYY_HHMMSS_TZ_SPACE = "[0-9][0-9] " MON " " YYYY " " HH_MM_DD " UTC"

        # 2007-02-28 11:48:53+02
        DATE_YYYY_MM_DD_DASH_HH_MM_SS_TZOFFSET = DATE_YYYY_MM_DD_DASH " " HH_MM_DD "\\+[0-9]+"
        split("january february march april may june july august september october november december", months, " ");
        for (i in months) {
            mon = months[i]
            Month[mon] = i;
            mon = substr(mon, 1, 3)
            Mon[mon] = i;
        }
    }

    # convert short month name to month number (Month Of Year)
    function mon2moy(month) {
        return Mon[tolower(month)]
    }

    # convert long month name to month number (Month Of Year)
    function month2moy(month) {
        return Month[tolower(month)]
    }

    # get date from DATE_ISO_FULL format from `s` using field separator `fs` from index `i` and exit
    function get_iso_date(s, fs, i,   a, d) {
        if (split(s, a, fs)) {
            if (split(a[i], d, /T/)) {
                print d[1];
                exit;
            }
        }
    }

    # Expiry date:  05-Dec-2014
    /Expir(y|ation) [Dd]ate:/ && $NF ~ DATE_DD_MON_YYYY {split($3, a, "-"); printf("%s-%s-%s\n", a[3], mon2moy(a[2]), a[1]); exit}

    # expires:      05-Dec-2014
    /expires:/ && $NF ~ DATE_DD_MON_YYYY {split($3, a, "-"); printf("%s-%s-%s\n", a[3], mon2moy(a[2]), a[1]); exit}

    # Expiry Date: 19/11/2015
    /Expiry Date:/ && $NF ~ DATE_DD_MM_YYYY_SLASH {split($3, a, "/"); printf("%s-%s-%s", a[3], a[2], a[1]); exit}

    # Expiration date: 16.11.2013 15:30:13
    /Expiration date:/ && $0 ~ DATE_DD_MM_YYYY_DOT_HH_MM_SS {split($(NF-1), a, "."); printf("%s-%s-%s", a[3], a[2], a[1]); exit}

    # Expire Date:  2015-10-22
    # expire-date:  2016-02-05
    /[Ee]xpire[- ][Dd]ate:/ && $NF ~ DATE_YYYY_MM_DD_DASH {print $NF; exit}

    # expires: 20170716
    /expires:/ && $NF ~ DATE_YYYY_MM_DD_NIL  {printf("%s-%s-%s", substr($2,0,4), substr($2,5,2), substr($2,7,2)); exit}

    # expires:  2015-11-18
    /expires:[ ]+/ && $NF ~ DATE_YYYY_MM_DD_DASH {print $NF; exit}

    # renewal date: 2016.01.14 18:47:31
    /renewal date:/ && $0 ~ DATE_YYYYMMDD_HHMMSS {split($(NF-1), a, "."); printf("%s-%s-%s", a[1], a[2], a[3]); exit}

    # paid-till: 2013.11.01
    /paid-till:/ && $NF ~ DATE_YYYY_MM_DD_DOT {split($2, a, "."); printf("%s-%s-%s", a[1], a[2], a[3]); exit}

    # paid-till: 2016-01-19
    /paid-till:/ && $NF ~ DATE_YYYY_MM_DD_DASH {print $NF; exit}

    # expire: 16.11.2013
    /expire:/ && $NF ~ DATE_DD_MM_YYYY_DOT {split($2, a, "."); printf("%s-%s-%s", a[3], a[2], a[1]); exit}

    # expire: 2016-01-19
    /expire:/ && $NF ~ DATE_YYYY_MM_DD_DASH {print $NF; exit}

    # Expiration Date: 2017-01-26T10:14:11Z
    # Registrar Registration Expiration Date: 2015-02-22T00:00:00Z
    # Registrar Registration Expiration Date: 2015-01-11T23:00:00-07:00Z
    $0 ~ "Expiration Date: " DATE_ISO_FULL { get_iso_date($0, ":", 2) }

    # domain_datebilleduntil: 2015-01-11T23:00:00-07:00Z
    $0 ~ "billed[ ]*until: " DATE_ISO_FULL { get_iso_date($0, ":", 2) }

    # Registrar Registration Expiration Date: 2018-09-21 00:00:00 -0400
    $0 ~ "Expiration Date: " DATE_ISO_LIKE { get_iso_date($0, ":", 2) }

    # Data de expiração / Expiration Date (dd/mm/yyyy): 18/01/2016
    $0 ~ "Expiration Date .dd/mm/yyyy" {split($NF, a, "/"); printf("%s-%s-%s", a[3], a[2], a[1]); exit}

    # Domain Expiration Date: Wed Mar 02 23:59:59 GMT 2016
    $0 ~ "Expiration Date: *" DATE_DAY_MON_DD_HHMMSS_TZ_YYYY {
        printf("%s-%s-%s", $9, mon2moy($5), $6);
    }

    # Expiration Date:02-May-2018 16:12:25 UTC
    $0 ~ "Expiration Date: *" DATE_DD_MON_YYYY_HHMMSS_TZ {
        sub(/^.*Expiration Date: */, "")
        split($1, a, "-");
        printf("%s-%s-%s", a[3], mon2moy(a[2]), a[1]);
    }

    # .sg domains
    # Expiration Date:      25-Apr-2018 16:00:50
    # (uses tabs between colon and date, we match tabs or spaces regardless)
    $0 ~ "Expiration Date:[ \t]*" DATE_DD_MON_YYYY_HHMMSS {
        sub(/^.*Expiration Date:[ \t]*/, "")
        split($1, a, "-");
        printf("%s-%s-%s", a[3], mon2moy(a[2]), a[1]);
    }

    # Expiry Date: 14 Jan 2016 22:40:29 UTC
    $0 ~ "Expiry Date: *" DATE_DD_MON_YYYY_HHMMSS_TZ_SPACE {
        printf("%s-%s-%s", $5, mon2moy($4), $3);
    }

    # Registry Expiry Date: 2015-08-03T04:00:00Z
    # Registry Expiry Date: 2017-01-26T10:14:11Z
    $0 ~ "Expiry Date: " DATE_ISO_FULL {split($0, a, ":"); s = a[2]; if (split(s,d,/T/)) print d[1]; exit}

    # Expiry date: 2017/07/16
    /Expiry date:/ && $NF ~ DATE_YYYY_MM_DD_SLASH {split($3, a, "/"); printf("%s-%s-%s", a[1], a[2], a[3]); exit}

    # Expiry Date: 19/11/2015 00:59:58
    /Expiry Date:/ && $(NF-1) ~ DATE_DD_MM_YYYY_SLASH {split($3, a, "/"); printf("%s-%s-%s", a[3], a[2], a[1]); exit}

    # Expires: 2014-01-31
    # Expiry : 2014-03-08
    # Valid-date 2014-10-21
    /Valid-date|Expir(es|ation|y)/ && $NF ~ DATE_YYYY_MM_DD_DASH {print $NF; exit}

    # [Expires on] 2014/12/01
    /\[Expires on\]/ && $NF ~ DATE_YYYY_MM_DD_SLASH {split($3, a, "/"); printf("%s-%s-%s", a[1], a[2], a[3]); exit}

    # [State] Connected (2014/12/01)
    /\[State\]/ && $NF ~ DATE_YYYY_MM_DD_SLASH {gsub("[()]", "", $3); split($3, a, "/"); printf("%s-%s-%s", a[1], a[2], a[3]); exit}

    # expires at: 21/05/2017 00:00:00 EEST
    $0 ~ "expires at: *" DATE_DD_MM_YYYY_SLASH_HHMMSS_TZ {split($3, a, "/"); printf("%s-%s-%s", a[3], a[2], a[1]); exit}

    # Renewal Date: 2016-06-25
    $0 ~ "Renewal Date: *" DATE_YYYY_MM_DD { print($3); exit}

    # Expiry Date: 31-03-2016
    $0 ~ "Expiry Date: *" DATE_DD_MM_YYYY {split($3, a, "-"); printf("%s-%s-%s", a[3], a[2], a[1]); exit}

    # Expired: 2015-10-03 13:36:48
    $0 ~ "Expired: *" DATE_YYYY_MM_DD_DASH_HH_MM_SS {split($2, a, "-"); printf("%s-%s-%s", a[1], a[2], a[3]); exit}

    # Expiration Time: 2015-10-03 13:36:48
    $0 ~ "Expiration Time: *" DATE_YYYY_MM_DD_DASH_HH_MM_SS {split($3, a, "-"); printf("%s-%s-%s", a[1], a[2], a[3]); exit}

    # .fi domains
    # expires............: 4.7.2017
    /^expires\.*: +[0-9][0-9]?\.[0-9][0-9]?\.[0-9][0-9][0-9][0-9]$/ {
        sub(/^expires\.*: +/, "")
        split($1, a, ".");
        printf("%s-%02d-%02d", a[3], a[2], a[1]);
        exit;
    }

    # .ua domain
    # expires: 2017-09-01 17:09:32+03
    $0 ~ "expires: *" DATE_YYYY_MM_DD_DASH_HH_MM_SS_TZOFFSET {split($2, a, "-"); printf("%s-%s-%s", a[1], a[2], a[3]); exit}
    # FIXME: XXX: weak patterns

    # renewal: 31-March-2016
    /renewal:/{split($2, a, "-"); printf("%s-%s-%s\n", a[3], month2moy(a[2]), a[1]); exit}

    # expires: March 5 2014
    /expires:/{printf("%s-%s-%s\n", $4, month2moy($2), $3); exit}

    # Renewal date:
    # Monday 21st Sep 2015
    /Renewal date:/{renewal = 1; next}
    {if (renewal) { sub(/[^0-9]+/, "", $2); printf("%s-%s-%s", $4, mon2moy($3), $2); exit}}

    # paid-till:     2017-12-10T12:42:36Z
    /paid-till:/ && $NF ~ DATE_ISO_FULL {split($0, a, ":"); s = a[2]; if (split(s,d,/T/)) print d[1]; exit}
    ' "$outfile"
}

set_defaults
parse_arguments "$@"

# We need to try up to 10 times because whois can be unreliable
for run in {1..10}; do
    if [ -n "$cache_dir" ]; then
        # we might consider whois server name in cache file
        outfile=$cache_dir/$domain

        # clean up cache file if it's outdated
        test -f "$outfile" && find "$outfile" -mtime +"$cache_age" -delete

        # run whois if cache is empty or missing
        test -s "$outfile" || run_whois
    else
        # shellcheck disable=SC2186
        outfile=$(tempfile)
        run_whois
    fi
    expiration=$(get_expiration "$outfile")

    if [ -n "$expiration" ] ; then
        break
    fi
    if [ "$run" -eq 10 ]; then
        die "$STATE_UNKNOWN" "UNKNOWN - Unable to figure out expiration date for $domain Domain."
    else
        sleep 1
    fi
done


expseconds=$(date +%s --date="$expiration")
expdate=$(date +'%Y-%m-%d' --date="$expiration")
nowseconds=$(date +%s)
diffseconds=$((expseconds-nowseconds))
expdays=$((diffseconds/86400))

# Trigger alarms (if applicable) if the domain is not expired.
if [ $expdays -ge 0 ]; then
    [ $expdays -lt "$critical" ] && die "$STATE_CRITICAL" "CRITICAL - Domain $domain will expire in $expdays days ($expdate). | domain_days_until_expiry=$expdays;$warning;$critical"
    [ $expdays -lt "$warning" ] && die "$STATE_WARNING" "WARNING - Domain $domain will expire in $expdays days ($expdate). | domain_days_until_expiry=$expdays;$warning;$critical"

    # No alarms? Ok, everything is right.
    die "$STATE_OK" "OK - Domain $domain will expire in $expdays days ($expdate). | domain_days_until_expiry=$expdays;$warning;$critical"
fi

# Trigger alarms if applicable in the case that $warning and/or $critical are negative
[ $expdays -lt "$critical" ] && die "$STATE_CRITICAL" "CRITICAL - Domain $domain expired ${expdays#-} days ago ($expdate). | domain_days_until_expiry=$expdays;$warning;$critical"
[ $expdays -lt "$warning" ] && die "$STATE_WARNING" "WARNING - Domain $domain expired ${expdays#-} days ago ($expdate). | domain_days_until_expiry=$expdays;$warning;$critical"
# No alarms? Ok, everything is right.
die "$STATE_OK" "OK - Domain $domain expired ${expdays#-} days ago ($expdate). | domain_days_until_expiry=$expdays;$warning;$critical"