#!/usr/local/bin/bash
# Copyright (C) 2019 Checkmk GmbH - License: GNU General Public License v2
# This file is part of Checkmk (https://checkmk.com). It is subject to the terms and
# conditions defined in the file COPYING, which is part of this source code package.

# Author: Lars Michelsen <lm@mathias-kettner.de>
#         Florian Heigl <florian.heigl@gmail.com>
#           (Added sections: df mount mem netctr ipmitool)

# NOTE: This agent has been adapted from the Checkmk linux agent.
#       The most sections are commented out at the moment because
#       they have not been ported yet. We will try to adapt most
#       sections to print out the same output as the linux agent so
#       that the current checks can be used.

# This might be a good source as description of sysctl output:
# http://people.freebsd.org/~hmp/utilities/satbl/_sysctl.html

#
# BEGIN COMMON AGENT CODE
#

###
# Note on agent package deployment modes:
# (Only relevant when deploying a Checkmk agent package manually)
# Agent paths (MK_LIBDIR, MK_CONFDIR, MK_VARDIR, MK_LOGDIR, MK_BIN)
# can be configured implicitly by setting MK_INSTALLDIR in function "set_up_single_directory()"
# or by setting the path variables explicitly under "set_default_paths()".
# Please refer to the official documentation for more details.
###

usage() {
    cat <<HERE
Usage: ${0} [OPTION...]

The Checkmk agent to monitor *nix style systems.

Options:
  -h, --help                 show this message and exit
  -d, --debug                emit debugging messages
  -p, --profile              create files containing the execution times
  --force-inventory          get the output of the agent plugin 'mk_inventory'
                             independent of the last run state.
HERE
}

inpath() {
    # replace "if type [somecmd]" idiom
    # 'command -v' tends to be more robust vs 'which' and 'type' based tests
    command -v "${1:?No command to test}" >/dev/null 2>&1
}

get_file_atime() {
    stat -c %X "${1}" 2>/dev/null ||
        stat -f %a "${1}" 2>/dev/null ||
        perl -e 'if (! -f $ARGV[0]){die "0000000"};$atime=(stat($ARGV[0]))[8];print $atime."\n";' "${1}"
}

get_file_mtime() {
    stat -c %Y "${1}" 2>/dev/null ||
        stat -f %m "${1}" 2>/dev/null ||
        perl -e 'if (! -f $ARGV[0]){die "0000000"};$mtime=(stat($ARGV[0]))[9];print $mtime."\n";' "${1}"
}

is_valid_plugin() {
    # test if a file is executable and does not have certain
    # extensions (remnants from distro upgrades).
    case "${1:?No plugin defined}" in
        *.dpkg-new | *.dpkg-old | *.dpkg-temp | *.dpkg-tmp) return 1 ;;
        *) [ -f "${1}" ] && [ -x "${1}" ] ;;
    esac
}

set_up_process_commandline_arguments() {
    while [ -n "${1}" ]; do
        case "${1}" in
            -d | --debug)
                set -xv
                DISABLE_STDERR=false
                shift
                ;;

            -p | --profile)
                LOG_SECTION_TIME=true
                # disable caching to get the whole execution time
                DISABLE_CACHING=true
                shift
                ;;

            --force-inventory)
                export MK_FORCE_INVENTORY=true
                shift
                ;;

            -h | --help)
                usage
                exit 1
                ;;

            *)
                shift
                ;;
        esac
    done
}

set_up_get_epoch() {
    # On some systems date +%s returns a literal %s
    if date +%s | grep "^[0-9].*$" >/dev/null 2>&1; then
        get_epoch() { date +%s; }
    else
        # do not check whether perl is even present.
        # in weird cases we may be fine without get_epoch.
        get_epoch() { perl -e 'print($^T."\n");'; }
    fi
}

set_up_current_shell() {
    # Note the current shell may not be the same as what is specified in the
    # shebang, e.g. when reconfigured in the xinetd/systemd/whateverd config file
    CURRENT_SHELL="$(ps -o args= -p $$ | cut -d' ' -f1)"
}

set_up_single_directory() {
    # Set this path when deploying the Checkmk agent installation
    # under a single directory.
    : "${MK_INSTALLDIR:=""}"
}

#
# END COMMON AGENT CODE
#

set_default_paths() {
    # Set/edit these paths when deploying the Checkmk agent installation
    # under multiple directories.
    # Will be ignored if MK_INSTALLDIR is already set and not empty.
    : "${MK_LIBDIR:="/usr/local/lib/check_mk_agent"}"
    : "${MK_CONFDIR:="/etc/check_mk"}"
    : "${MK_VARDIR:="/var/lib/check_mk_agent"}"
    : "${MK_LOGDIR:="/var/log/check_mk_agent"}"
    : "${MK_BIN:="/usr/bin"}"
}

preamble_1() {
    # Make sure locally installed binaries are found
    # Only add binaries if they are not already in the path! If you append to path in a loop the process will
    # eventually each the 128k size limit for the environment and become a zombie process. See execve manpage.
    [ "${PATH#*"/usr/local/bin"}" != "${PATH}" ] || PATH="${PATH}:/usr/local/bin"
    [ "${PATH#*"/usr/local/sbin"}" != "${PATH}" ] || PATH="${PATH}:/usr/local/sbin"
    [ -d "/var/qmail/bin" ] && { [ "${PATH#*"/var/qmail/bin"}" != "${PATH}" ] || PATH="${PATH}:/var/qmail/bin"; }
}

# encryption not implemented
optionally_encrypt() { cat; }
#
# BEGIN COMMON AGENT CODE
#

determine_sync_async() {
    # some 'booleans'
    [ "${MK_RUN_SYNC_PARTS}" = "false" ] || MK_RUN_SYNC_PARTS=true
    [ "${MK_RUN_ASYNC_PARTS}" = "false" ] || MK_RUN_ASYNC_PARTS=true
}

provide_agent_paths() {
    # If MK_INSTALLDIR is set, this will always win over separately set agent paths
    [ -n "${MK_INSTALLDIR}" ] && {
        MK_LIBDIR="${MK_INSTALLDIR}/package"
        MK_CONFDIR="${MK_INSTALLDIR}/package/config"
        MK_VARDIR="${MK_INSTALLDIR}/runtime"
        MK_LOGDIR="${MK_INSTALLDIR}/runtime/log"
        MK_BIN="${MK_INSTALLDIR}/package/bin"
    }

    export MK_LIBDIR
    export MK_CONFDIR
    export MK_VARDIR
    export MK_LOGDIR
    export MK_BIN

    # Optionally set a tempdir for all subsequent calls
    #export TMPDIR=

    # All executables in PLUGINSDIR will simply be executed and their
    # ouput appended to the output of the agent. Plugins define their own
    # sections and must output headers with '<<<' and '>>>'
    PLUGINSDIR=${MK_LIBDIR}/plugins

    # All executables in LOCALDIR will by executabled and their
    # output inserted into the section <<<local>>>. Please
    # refer to online documentation for details about local checks.
    LOCALDIR=${MK_LIBDIR}/local

    # All files in SPOOLDIR will simply appended to the agent
    # output if they are not outdated (see below)
    SPOOLDIR=${MK_VARDIR}/spool

    # JOBDIR contains subfolders with snippets of agent output
    # coming from the mk-job executable.
    # These snippets will be used to create the <<<job>>> section.
    JOBDIR=${MK_VARDIR}/job

    # Cache directory for agent output from asynchonous parts of the agent and plugins.
    # Handled in a sophisticated way by our caching mechanism.
    CACHEDIR=${MK_VARDIR}/cache
}

# SC2089: Quotes/backslashes will be treated literally. Use an array.
# shellcheck disable=SC2089
MK_DEFINE_LOG_SECTION_TIME='_log_section_time() { "$@"; }'
finalize_profiling() { :; }

set_up_profiling() {

    PROFILING_CONFIG="${MK_CONFDIR}/profiling.cfg"
    if [ -e "${PROFILING_CONFIG}" ]; then
        # Config vars:
        #   LOG_SECTION_TIME=true/false
        #   DISABLE_CACHING=true/false

        # If LOG_SECTION_TIME=true via profiling.cfg do NOT disable caching in order
        # to get the real execution time during operation.
        # shellcheck disable=SC1090
        . "${PROFILING_CONFIG}"
    fi

    PROFILING_LOGFILE_DIR="${MK_LOGDIR}/profiling/$(date +%Y%m%d_%H%M%S)"

    if ${LOG_SECTION_TIME:-false}; then
        mkdir -p "${PROFILING_LOGFILE_DIR}"
        agent_start="$(perl -MTime::HiRes=time -le 'print time()')"

        # SC2016: Expressions don't expand in single quotes, use double quotes for that.
        # SC2089: Quotes/backslashes will be treated literally. Use an array.
        # shellcheck disable=SC2016,SC2089
        MK_DEFINE_LOG_SECTION_TIME='_log_section_time() {
            section_func="$@"

            base_name=$(echo "${section_func}" | sed "s/[^A-Za-z0-9.-]/_/g")
            profiling_logfile="'"${PROFILING_LOGFILE_DIR}"'/${base_name}.log"

            start="$(perl -MTime::HiRes=time -le "print time()")"
            { time ${section_func}; } 2>> "${profiling_logfile}"
            echo "runtime $(perl -MTime::HiRes=time -le "print time() - ${start}")" >> "${profiling_logfile}"
        }'

        finalize_profiling() {
            pro_log_file="${PROFILING_LOGFILE_DIR}/profiling_check_mk_agent.log"
            agent_end="$(perl -MTime::HiRes=time -le 'print time()')"
            echo "runtime $(echo "${agent_end} - ${agent_start}" | bc)" >>"${pro_log_file}"
        }
    fi

    eval "${MK_DEFINE_LOG_SECTION_TIME}"
    # SC2090: Quotes/backslashes in this variable will not be respected.
    # shellcheck disable=SC2090
    export MK_DEFINE_LOG_SECTION_TIME
}

unset_locale() {
    # eliminate localized outputs where possible
    # The locale logic here is used to make the Python encoding detection work (see CMK-2778).
    unset -v LANG LC_ALL
    if inpath locale && inpath paste; then
        # match C.UTF-8 at the beginning, but not e.g. es_EC.UTF-8!
        case "$(locale -a | paste -sd ' ' -)" in
            *' C.UTF-8'* | 'C.UTF-8'*) LC_ALL="C.UTF-8" ;;
            *' C.utf8'* | 'C.utf8'*) LC_ALL="C.utf8" ;;
        esac
    fi
    LC_ALL="${LC_ALL:-C}"
    export LC_ALL
}

read_python_version() {
    if inpath "${1}"; then
        version=$(${1} -c 'import sys; print("%s.%s"%(sys.version_info[0], sys.version_info[1]))')

        major=${version%%.*}
        minor=${version##*.}

        if [ "${major}" -eq "${2}" ] && [ "${minor}" -ge "${3}" ]; then
            echo "${1}"
            return 0
        fi
    fi
    return 1
}

detect_python() {
    PYTHON3=$(read_python_version python3 3 4 || read_python_version python 3 4)
    PYTHON2=$(read_python_version python2 2 6 || read_python_version python 2 6)
    if [ -f "${MK_CONFDIR}/python_path.cfg" ]; then
        # shellcheck source=/dev/null
        . "${MK_CONFDIR}/python_path.cfg"
    fi
    export PYTHON2 PYTHON3

    if [ -z "${PYTHON2}" ] && [ -z "${PYTHON3}" ]; then
        NO_PYTHON=true
    elif [ -n "${PYTHON3}" ] && [ "$(
        ${PYTHON3} -c 'pass' >/dev/null 2>&1
        echo $?
    )" -eq 127 ]; then
        WRONG_PYTHON_COMMAND=true
    elif [ -z "${PYTHON3}" ] && [ "$(
        ${PYTHON2} -c 'pass' >/dev/null 2>&1
        echo $?
    )" -eq 127 ]; then
        WRONG_PYTHON_COMMAND=true
    fi
}

#
# END COMMON AGENT CODE
#

section_checkmk() {
    echo "<<<check_mk>>>"
    echo "Version: 2.4.0b1"
    echo "AgentOS: freebsd"
    echo "Hostname: $(hostname)"
    echo "AgentDirectory: ${MK_CONFDIR}"
    echo "DataDirectory: ${MK_VARDIR}"
    echo "SpoolDirectory: ${SPOOLDIR}"
    echo "PluginsDirectory: ${PLUGINSDIR}"
    echo "LocalDirectory: ${LOCALDIR}"
    echo "OSType: unix"

    while read -r line; do
        raw_line="${line//\"/}"
        case $line in
            NAME=*) echo "OSName: ${raw_line##*=}" ;;
            VERSION_ID=*) echo "OSVersion: ${raw_line##*=}" ;;
        esac
    done </etc/os-release 2>/dev/null

    #
    # BEGIN COMMON AGENT CODE
    #

    if [ -n "${NO_PYTHON}" ]; then
        python_fail_msg="No suitable python installation found."
    elif [ -n "${WRONG_PYTHON_COMMAND}" ]; then
        python_fail_msg="Configured python command not found."
    fi

    cat <<HERE
FailedPythonReason: ${python_fail_msg}
SSHClient: ${SSH_CLIENT}
HERE
}

section_cmk_agent_ctl_status() {
    cmk-agent-ctl --version 2>/dev/null >&2 || return

    printf "<<<cmk_agent_ctl_status:sep(0)>>>\n"
    cmk-agent-ctl status --json --no-query-remote
}

section_checkmk_agent_plugins() {
    printf "<<<checkmk_agent_plugins_lnx:sep(0)>>>\n"
    printf "pluginsdir %s\n" "${PLUGINSDIR}"
    printf "localdir %s\n" "${LOCALDIR}"
    for script in \
        "${PLUGINSDIR}"/* \
        "${PLUGINSDIR}"/[1-9]*/* \
        "${LOCALDIR}"/* \
        "${LOCALDIR}"/[1-9]*/*; do
        if is_valid_plugin "${script}"; then
            script_version=$(grep -e '^__version__' -e '^CMK_VERSION' "${script}" || echo 'CMK_VERSION="unversioned"')
            printf "%s:%s\n" "${script}" "${script_version}"
        fi
    done
}

section_checkmk_failed_plugin() {
    ${MK_RUN_SYNC_PARTS} || return
    echo "<<<check_mk>>>"
    echo "FailedPythonPlugins: ${1}"
}

#
#

section_job() {
    # Get statistics about monitored jobs.

    _cat_files() {
        # read file names from stdin and write like `head -n -0 -v file`
        while read -r file; do
            printf "==> %s <==\n" "${file##./}"
            cat "${file}"
        done
    }

    (
        cd "${JOBDIR}" 2>/dev/null || return
        printf "<<<job>>>\n"
        for user in *; do
            (
                cd "${user}" 2>/dev/null || return # return from subshell only
                # This folder is owned (and thus writable) by the user that ran the jobs.
                # The agent (root) must not read files that are not owned by the user.
                # This prevents symlink or hardlink attacks.
                find -L . -type f -user "${user}" | _cat_files
            )
        done
    )
}

section_fileinfo() {
    # fileinfo check: put patterns for files into /etc/check_mk/fileinfo.cfg
    perl -e '
    use File::Glob "bsd_glob";
    my @patterns = ();
    foreach (bsd_glob("$ARGV[0]/fileinfo.cfg"), bsd_glob("$ARGV[0]/fileinfo.d/*")) {
        open my $handle, "<", $_ or next;
        while (<$handle>) {
            chomp;
            next if /^\s*(#|$)/;
            my $pattern = $_;
            $pattern =~ s/\$DATE:(.*?)\$/substr(`date +"$1"`, 0, -1)/eg;
            push @patterns, $pattern;
        }
        warn "error while reading $_: $!\n" if $!;
        close $handle;
    }
    exit if ! @patterns;

    my $file_stats = "";
    foreach (@patterns) {
        foreach (bsd_glob("$_")) {
            if (! -f) {
                $file_stats .= "$_|missing\n" if ! -d;
            } elsif (my @infos = stat) {
                $file_stats .= "$_|ok|$infos[7]|$infos[9]\n";
            } else {
                $file_stats .= "$_|stat failed: $!\n";
            }
        }
    }

    print "<<<fileinfo:sep(124)>>>\n", time, "\n[[[header]]]\nname|status|size|time\n[[[content]]]\n$file_stats";
    ' -- "${MK_CONFDIR}"
}

#
# END COMMON AGENT CODE
#

section_sysctlmem() {
    # Output FreeBSD memory info from sysctl
    printf '<<<sysctl_mem>>>\n'
    sysctl "vm.stats.vm.v_page_size" "vm.stats.vm.v_cache_count" "vm.stats.vm.v_free_count" "vm.kmem_size" "vm.swap_total"
    printf "swap.used %s\n" "$(($(swapinfo | tail -1 | awk '{print $3}') * 1024))"
}

run_purely_synchronous_sections() {

    section_checkmk

    section_cmk_agent_ctl_status

    section_checkmk_agent_plugins

    section_sysctlmem

    osver="$(uname -r)"
    is_jailed="$(sysctl -n security.jail.jailed)"

    # Partitionen (-P verhindert Zeilenumbruch bei langen Mountpunkten)
    # Achtung: NFS-Mounts werden grundsaetzlich ausgeblendet, um
    # Haenger zu vermeiden. Diese sollten ohnehin besser auf dem
    # Server, als auf dem Client ueberwacht werden.

    echo '<<<df>>>'
    # no special zfs handling so far, the ZFS.pools plugin has been tested to
    # work on FreeBSD
    if df -T >/dev/null; then
        df -kTP -t ufs | grep -v -E '(Filesystem|devfs|procfs|fdescfs|basejail)'
    else
        df -kP -t ufs | grep -v -E '(Filesystem|devfs|procfs|fdescfs|basejail)' | awk '{ print $1,"ufs",$2,$3,$4,$5,$6 }'
    fi

    # Filesystem usage for ZFS
    if inpath zfs; then
        echo '<<<zfsget>>>'
        zfs get -t filesystem,volume -Hp name,quota,used,avail,mountpoint,type ||
            zfs get -Hp name,quota,used,avail,mountpoint,type
        echo '[df]'
        df -kP -t zfs | sed 1d
        # arc stats for zfs_arc_cache
        echo '<<<zfs_arc_cache>>>'
        sysctl -q kstat.zfs.misc.arcstats | sed -e 's/kstat.zfs.misc.arcstats.//g' -e 's/: / = /g'
    fi

    # Check NFS mounts by accessing them with stat -f (System
    # call statfs()). If this lasts more then 2 seconds we
    # consider it as hanging. We need waitmax.
    #if inpath waitmax
    #then
    #    STAT_VERSION=$(stat --version | head -1 | cut -d" " -f4)
    #    STAT_BROKE="5.3.0"
    #
    #    echo '<<<nfsmounts>>>'
    #    sed -n '/ nfs /s/[^ ]* \([^ ]*\) .*/\1/p' < /proc/mounts |
    #        while read MP
    #  do
    #   if [ ${STAT_VERSION} != ${STAT_BROKE} ]; then
    #      waitmax -s 9 2 stat -f -c "${MP} ok %b %f %a %s" "${MP}" || \
    #    echo "${MP} hanging 0 0 0 0"
    #   else
    #      waitmax -s 9 2 stat -f -c "${MP} ok %b %f %a %s" "${MP}" && \
    #      printf '\n'|| echo "${MP} hanging 0 0 0 0"
    #   fi
    #  done
    #fi

    # Check mount options.
    # FreeBSD doesn't do remount-ro on errors, but the users might consider
    # security related mount options more important.
    echo '<<<mounts>>>'
    mount -p -t ufs

    # processes including username, without kernel processes
    echo '<<<ps>>>'
    echo "[time]"
    get_epoch
    echo "[processes]"
    if [ "${is_jailed}" = "0" ]; then
        ps ax -ww -o state,user,vsz,rss,pcpu,command | sed -e 1d -e '/\([^ ]*J\) */d' -e 's/ *\([^ ]*\) *\([^ ]*\) *\([^ ]*\) *\([^ ]*\) *\([^ ]*\) */(\2,\3,\4,\5) /'
    else
        ps ax -ww -o user,vsz,rss,pcpu,command | sed -e 1d -e 's/ *\([^ ]*\) *\([^ ]*\) *\([^ ]*\) *\([^ ]*\) */(\1,\2,\3,\4) /'
    fi

    # Produce compatible load/cpu output to linux agent. Not so easy here.
    echo '<<<cpu>>>'
    printf "%s %s %s %s\n" \
        "$(sysctl -n vm.loadavg | tr -d '{}')" \
        "$(top -b -n 1 | grep -E '^[0-9]+ processes' | awk '{print $3"/"$1}')" \
        "$(sysctl -n kern.lastpid)" \
        "$(sysctl -n hw.ncpu)"

    # Calculate the uptime in seconds since epoch compatible to /proc/uptime in linux
    echo '<<<uptime>>>'
    up_seconds=$(($(get_epoch) - $(sysctl -n kern.boottime | cut -f1 -d\, | awk '{print $4}')))
    idle_seconds=$(ps axw | grep idle | grep -v grep | awk '{print $4}' | cut -f1 -d:)
    echo "${up_seconds} ${idle_seconds}"

    # Platten- und RAID-Status von LSI-Controlleren, falls vorhanden
    #if inpath cfggen; then
    #   echo '<<<lsi>>>'
    #   cfggen 0 DISPLAY | grep -E '(Target ID|State|Volume ID|Status of volume)[[:space:]]*:' | sed -e 's/ *//g' -e 's/:/ /'
    #fi

    # Multipathing is supported in FreeBSD by now
    # http://www.mywushublog.com/2010/06/freebsd-and-multipath/
    if kldstat -v | grep g_multipath >/dev/null; then
        echo '<<<freebsd_multipath>>>'
        gmultipath status | grep -v ^Name
    fi

    # Soft-RAID
    echo '<<<freebsd_geom_mirrors>>>'
    gmirror status | grep -v ^Name

    # Performancecounter Kernel
    echo "<<<kernel>>>"
    get_epoch
    forks=$(sysctl -n vm.stats.vm.v_forks)
    vforks=$(sysctl -n vm.stats.vm.v_vforks)
    rforks=$(sysctl -n vm.stats.vm.v_rforks)
    kthreads=$(sysctl -n vm.stats.vm.v_kthreads)
    echo "cpu $(sysctl -n kern.cp_time | awk ' { print $1" "$2" "$3" "$5" "$4 } ')"
    echo "ctxt $(sysctl -n vm.stats.sys.v_swtch)"
    echo "processes $((forks + vforks + rforks + kthreads))"

    # Network device statistics (Packets, Collisions, etc)
    # only the "Link/Num" interface has all counters.
    echo '<<<netctr>>>'
    get_epoch
    if [ "$(echo "${osver}" | cut -f1 -d\.)" -gt "8" ]; then
        netstat -inb | grep -v -E '(^Name|lo|plip)' | grep Link | awk '{print $1" "$8" "$5" "$6" "$7" 0 0 0 0 "$11" "$9" "$10" 0 0 0 0 0"}'
    else
        # pad output for freebsd 7 and before
        netstat -inb | grep -v -E '(^Name|lo|plip)' | grep Link | awk '{print $1" "$7" "$5" "$6" 0 0 0 0 0 "$10" "$8" "$9" 0 0 "$11" 0 0"}'
    fi

    # IPMI-Data (Fans, CPU, temperature, etc)
    # needs the sysutils/ipmitool and kldload ipmi.ko
    if inpath ipmitool; then
        echo '<<<ipmi>>>'
        ipmitool sensor list |
            grep -v 'command failed' |
            sed -e 's/ *| */|/g' -e "s/ /_/g" -e 's/_*$//' -e 's/|/ /g' |
            grep -v -E '^[^ ]+ na ' |
            grep -v ' discrete '
    fi

    # State of LSI MegaRAID controller via MegaCli.
    # To install: pkg install megacli
    if inpath MegaCli; then
        echo '<<<megaraid_pdisks>>>'
        MegaCli -PDList -aALL -NoLog </dev/null | grep -E 'Enclosure|Raw Size|Slot Number|Device Id|Firmware state|Inquiry|Predictive Failure Count'
        echo '<<<megaraid_ldisks>>>'
        MegaCli -LDInfo -Lall -aALL -NoLog </dev/null | grep -E 'Size|State|Number|Adapter|Virtual'
        echo '<<<megaraid_bbu>>>'
        MegaCli -AdpBbuCmd -GetBbuStatus -aALL -NoLog </dev/null | grep -v Exit
    fi

    # OpenVPN Clients.
    # Correct log location unknown, sed call might also be broken
    if [ -e /var/log/openvpn/openvpn-status.log ]; then
        echo '<<<openvpn_clients:sep(44)>>>'
        sed -n -e '/CLIENT LIST/,/ROUTING TABLE/p' </var/log/openvpn/openvpn-status.log | sed -e 1,3d -e '$d'
    fi

    if inpath ntpq; then
        echo '<<<ntp>>>'
        # remote heading, make first column space separated
        ntpq -np | sed -e 1,2d -e 's/^\(.\)/\1 /' -e 's/^ /%/'
    fi

    # Number of TCP connections in the various states
    echo '<<<tcp_conn_stats>>>'
    netstat -na | awk ' /^tcp/ { c[$6]++; } END { for (x in c) { print x, c[x]; } }'

    # Postfix mailqueue monitoring
    #
    # Only handle mailq when postfix user is present. The mailq command is also
    # available when postfix is not installed. But it produces different outputs
    # which are not handled by the check at the moment. So try to filter out the
    # systems not using postfix by searching for the postfix user.
    #
    # Cannot take the whole outout. This could produce several MB of agent output
    # on blocking queues.
    # Only handle the last 6 lines (includes the summary line at the bottom and
    # the last message in the queue. The last message is not used at the moment
    # but it could be used to get the timestamp of the last message.
    if inpath postconf; then
        echo '<<<postfix_mailq>>>'
        postfix_queue_dir=$(postconf -h queue_directory)
        postfix_count=$(find "${postfix_queue_dir}/deferred" -type f | wc -l)
        postfix_size=$(du -ks "${postfix_queue_dir}/deferred" | awk '{print $1 }')
        if [ "${postfix_count}" -gt 0 ]; then
            echo -- "${postfix_size} Kbytes in ${postfix_count} Requests."
        else
            echo Mail queue is empty
        fi
    elif [ -x /usr/sbin/ssmtp ]; then
        echo '<<<postfix_mailq>>>'
        mailq 2>&1 | sed 's/^[^:]*: \(.*\)/\1/' | tail -n 6
    fi

    # Check status of qmail mailqueue
    if inpath qmail-qstat; then
        echo "<<<qmail_stats>>>"
        qmail-qstat
    fi

    # check zpool status
    if inpath zpool; then
        echo "<<<zpool_status>>>"
        zpool status -x | grep -v "errors: No known data errors"
    fi

    # Statgrab
    # To install: pkg install libstatgrab
    if inpath statgrab; then

        tmpfile="/tmp/statgrab.$$"

        statgrab const. disk. general. page. proc. user. | grep -v md >"${tmpfile}"
        statgrab mem. swap. >>"${tmpfile}"

        for s in proc disk page; do
            echo "<<<statgrab_${s}>>>"
            grep "^${s}\." "${tmpfile}" | cut -d. -f2-99 | sed 's/ *= */ /'
        done

        echo '<<<statgrab_net>>>'
        statgrab net. 2>&1 | cut -d. -f2-99 | sed 's/ *= */ /'

        rm -f "${tmpfile}"
    fi
}

#
# BEGIN COMMON AGENT CODE
#

run_cached() {
    # Compatibility wrapper for plugins that might use run_cached.
    # We should have never exposed this as quasi API.
    NAME="${1}"
    MAXAGE="${2}"
    REFRESH_INTERVAL="${3}"
    shift 3

    OUTPUT_TIMEOUT=$((MAXAGE * 3))
    CREATION_TIMEOUT=$((MAXAGE * 2))

    _run_cached_internal "${NAME}" "${REFRESH_INTERVAL}" "${MAXAGE}" "${OUTPUT_TIMEOUT}" "${CREATION_TIMEOUT}" "$@"
}

if inpath setsid; then
    # we can kill the whole process group, including children.
    _nohup_kill_id() { printf "0"; }
    _nohup() { setsid nohup "$@"; }
else
    # we can only the main process, children will survive :-/
    _nohup_kill_id() { printf "\$\$"; }
    _nohup() { nohup "$@"; }
fi

_run_cached_internal() {
    # Run a command asynchronous by use of a cache file.
    # Usage: _run_cached_internal NAME REFRESH_INTERVAL MAXAGE OUTPUT_TIMEOUT OUTPUT_TIMEOUT CREATION_TIMEOUT [COMMAND ...]
    # Note that while multiple COMMAND arguments are considered, they are evaluated in a string.
    # This means that extra escaping is required.
    # For example:
    # To run a cat command every two minutes, considering the created data valid for one three minutes,
    # send the created data for four minutes and allowing the command to run for 12 minutes, you'll have to call
    #
    #   _run_cached_interal "my_file_content" 120 180 240 720 "cat \"My File\""
    #
    # Mind the escaping...

    NAME="${1}"
    # name of the section (also used as cache file name)

    REFRESH_INTERVAL="${2}"
    # threshold in seconds when the cache file needs to be regenerated

    MAXAGE="${3}"
    # maximum cache livetime in seconds

    OUTPUT_TIMEOUT="${4}"
    # threshold in seconds for how long the cache file will be output (regardless of whether it is outdated)

    CREATION_TIMEOUT="${5}"
    # threshold in seconds for how long the process is allowed to be running before it is killed (see below for details)

    shift 5
    # $* is now the command to run

    if ${DISABLE_CACHING:-false}; then
        # We need the re-splitting to be compatible with the caching case, so:
        # shellcheck disable=SC2068
        $@
        return
    fi

    [ -d "${CACHEDIR}" ] || mkdir -p "${CACHEDIR}"
    CACHEFILE="${CACHEDIR}/${NAME}.cache"
    FAIL_REPORT_FILE="${SPOOLDIR}/${NAME}.cachefail"

    NOW="$(get_epoch)"
    MTIME="$(get_file_mtime "${CACHEFILE}" 2>/dev/null)" || MTIME=0

    if ${MK_RUN_SYNC_PARTS}; then
        if [ -s "${CACHEFILE}" ] && [ $((NOW - MTIME)) -le "${OUTPUT_TIMEOUT}" ]; then
            # Output the file (if it is not too outdated)
            CACHE_INFO="cached(${MTIME},${MAXAGE})"
            # prefix or insert cache info, unless already present.
            # WATCH OUT: AIX does not allow us to pass this as a single '-e' option!
            if [ "${NAME%%_*}" = "local" ] || [ "${NAME%%_*}" = "mrpe" ]; then
                sed -e '/^<<<.*>>>/{p;d;}' -e '/^cached([0-9]*,[0-9]*) /{p;d;}' -e "s/^/${CACHE_INFO} /" "${CACHEFILE}"
            else
                sed -e '/^<<<.*\(:cached(\).*>>>/{p;d;}' -e 's/^<<<\([^>]*\)>>>$/<<<\1:'"${CACHE_INFO}"'>>>/' "${CACHEFILE}"
            fi
        fi

    fi

    if ${MK_RUN_ASYNC_PARTS}; then
        # This does the right thing, regardless whether the pattern matches!
        _cfile_in_use() {
            for cfile in "${CACHEFILE}.new."*; do
                printf "%s\n" "${cfile}"
                break
            done
        }

        # Time to refresh cache file and new job not yet running?
        if [ $((NOW - MTIME)) -gt "${REFRESH_INTERVAL}" ] && [ ! -e "$(_cfile_in_use)" ]; then

            # Start it.
            # We're running two parrallel blocks, implementing a timeout. Roughly:
            # First block: Run command then kill ourselves (including the other block!)
            # Second block: Sleep for a while. If I survive: Handle the fact that block one did not kill me.
            cat <<HERE | _nohup "${CURRENT_SHELL}" >/dev/null 2>&1 &
             {
                eval '${MK_DEFINE_LOG_SECTION_TIME}'
                exec > "${CACHEFILE}.new.\$\$" || exit 1
                $* \
                && mv -f "${CACHEFILE}.new.\$\$" "${CACHEFILE}" && rm -f "${FAIL_REPORT_FILE}" \
                || rm -f "${CACHEFILE}.new.\$\$"
                kill $(_nohup_kill_id)
             } &
             {
                sleep ${CREATION_TIMEOUT}
                {
                      printf "<<<checkmk_cached_plugins:sep(124)>>>\\n"
                      printf "timeout|${NAME}|${CREATION_TIMEOUT}|\$\$\\n"
                } >"${FAIL_REPORT_FILE}" 2>&1
                rm -f "${CACHEFILE}.new.\$\$"
                kill -9 $(_nohup_kill_id)
             } &
HERE
        fi

    fi

    unset NAME MAXAGE CREATION_TIMEOUT REFRESH_INTERVAL CACHEFILE NOW MTIME CACHE_INFO TRYING_SINCE OUTPUT_TIMEOUT
}

run_local_checks() {
    cd "${LOCALDIR}" || return

    if ${MK_RUN_SYNC_PARTS}; then
        echo '<<<local:sep(0)>>>'
        for script in ./*; do
            if is_valid_plugin "${script}"; then
                _log_section_time "${script}"
            fi
        done
    fi

    # Call some local checks only every X'th second
    for script in [1-9]*/*; do
        if is_valid_plugin "${script}"; then
            interval="${script%/*}"
            _run_cached_internal "local_${script##*/}" "${interval}" "${interval}" $((interval * 3)) $((interval * 2)) "_log_section_time '${script}'"
        fi
    done
}

run_spooler() {
    (
        cd "${SPOOLDIR}" 2>/dev/null || return

        now=$(get_epoch)

        for file in *; do
            [ "${file}" != "*" ] || return

            # If prefixed with a number, then that is the maximum age in seconds.
            # If the file is older than that, it is ignored.
            maxage="${file%%[^0-9]*}"
            if [ "${maxage}" ]; then
                mtime=$(get_file_mtime "${file}")
                [ $((now - mtime)) -le "${maxage}" ] || continue
            fi

            cat "${file}"
        done
    )
}

get_plugin_interpreter() {
    # Return the interpreter (or "") for the plugin file (or fail).
    # We return the interpreter instead of wrapping the call, so we don't
    # have to export the function (which is not portable).

    # normalize input
    agent_plugin="${1#./}"

    extension="${agent_plugin##*.}"
    filename="${agent_plugin%.*}"

    # Execute all non python plugins with ./foo
    if [ "${extension}" != "py" ]; then
        return 0
    fi

    if [ "${filename#"${filename%??}"}" != "_2" ]; then
        if [ -n "${NO_PYTHON}" ] || [ -n "${WRONG_PYTHON_COMMAND}" ]; then
            section_checkmk_failed_plugin "${agent_plugin}"
            return 1
        fi

        if [ -n "${PYTHON3}" ]; then
            echo "${PYTHON3}"
            return 0
        fi

        if [ ! -e "${filename}_2.py" ]; then
            section_checkmk_failed_plugin "${agent_plugin} (Missing Python 3 installation)"
            return 1
        fi

        # no python3 found, but python2 plugin file present
        return 1
    fi

    if [ -x "${filename%??}.py" ] && [ -n "${PYTHON3}" ]; then
        return 1
    fi

    if [ -n "${PYTHON2}" ]; then
        echo "${PYTHON2}"
        return 0
    fi

    section_checkmk_failed_plugin "${agent_plugin} (missing Python 2 installation)"
    return 1
}

run_plugins() {
    cd "${PLUGINSDIR}" || return

    if ${MK_RUN_SYNC_PARTS}; then
        for script in ./*; do
            if is_valid_plugin "${script}"; then
                if plugin_interpreter=$(get_plugin_interpreter "${script}"); then
                    # SC2086: We don't want to quote, interpreter is "nothing" if empty, not "''"
                    # shellcheck disable=SC2086
                    _log_section_time ${plugin_interpreter} "${script}"
                fi
            fi
        done
    fi

    # Call some plugins only every X'th second
    for script in [1-9]*/*; do
        if is_valid_plugin "${script}"; then
            if plugin_interpreter=$(get_plugin_interpreter "${script}"); then
                interval="${script%/*}"
                # shellcheck disable=SC2086
                _run_cached_internal "plugins_${script##*/}" "${interval}" "${interval}" $((interval * 3)) $((interval * 2)) _log_section_time ${plugin_interpreter} "${script}"
            fi
        fi
    done
}

_non_comment_lines() {
    grep -Ev '^[[:space:]]*($|#)' "${1}"
}

_mrpe_get_interval() {
    echo "${1}" | grep -E '^\([^)]*\)' | sed -n 's/^.*interval=\([^:)]*\).*$/\1/p'
}

_mrpe_normalize_spaces() {
    # watch out:
    # * [:blank:] does not include \t on AIX
    # * [:space:] does include \n on Linux
    tr -s '\t' ' '
}

run_remote_plugins() {
    configfile="${1}"
    prefix="${2}"
    [ -f "${configfile}" ] || return

    _non_comment_lines "${configfile}" | _mrpe_normalize_spaces | while read -r descr rest; do
        interval="$(_mrpe_get_interval "${rest}")"
        cmdline="${rest#\(*\) }"

        if [ -n "${prefix}" ]; then
            cmdline="${prefix} '${cmdline}'"
        fi

        if [ -z "${interval}" ]; then
            ${MK_RUN_SYNC_PARTS} && run_mrpe "${descr}" "${cmdline}"
        else
            # Sourcing the agent here is not very performant, but we need 'run_mrpe', and not all shells support exporting of functions.
            _run_cached_internal "mrpe_${descr}" "${interval}" "${interval}" $((interval * 3)) $((interval * 2)) "MK_SOURCE_AGENT=yes . '${0}'; run_mrpe \"${descr}\" \"${cmdline}\""
        fi

    done
}

run_mrpe() {
    descr="${1}"
    shift

    PLUGIN="${1%% *}"
    OUTPUT="$(eval "${MK_DEFINE_LOG_SECTION_TIME}; _log_section_time $*")"
    STATUS="$?"

    printf "<<<mrpe>>>\n"
    printf "(%s) %s %s %s" "${PLUGIN##*/}" "${descr}" "${STATUS}" "${OUTPUT}" | tr \\n \\1
    printf "\n"

    unset descr PLUGIN OUTPUT STATUS
}

#
# END COMMON AGENT CODE
#

run_partially_asynchronous_sections() {
    # kept to keep agents similar. Currently no section in this agent calls run_cached.
    :
}

main_setup() {

    exec </dev/null

    set_up_process_commandline_arguments "$@"

    if "${DISABLE_STDERR:-true}"; then
        exec 2>/dev/null
    fi

    set_up_get_epoch

    set_up_current_shell

    determine_sync_async

    set_up_single_directory
    set_default_paths
    provide_agent_paths

    unset_locale

    detect_python

    preamble_1

    set_up_profiling

}

main_sync_parts() {
    run_purely_synchronous_sections

    section_fileinfo

    run_spooler
}

main_mixed_parts() {
    run_partially_asynchronous_sections

    run_local_checks

    run_plugins

    run_remote_plugins "${MK_CONFDIR}/mrpe.cfg"
}

main_async_parts() {
    :
}

main_finalize_sync() {
    finalize_profiling
}

#
# BEGIN COMMON AGENT CODE
#

main() {

    while true; do

        main_setup "$@"

        (

            ${MK_RUN_SYNC_PARTS} && main_sync_parts

            (${MK_RUN_ASYNC_PARTS} || ${MK_RUN_SYNC_PARTS}) && main_mixed_parts

            ${MK_RUN_ASYNC_PARTS} && main_async_parts

            ${MK_RUN_SYNC_PARTS} && main_finalize_sync

        ) | { if ${MK_RUN_SYNC_PARTS}; then optionally_encrypt "${PASSPHRASE}" ""; else cat; fi; }

        [ "${MK_LOOP_INTERVAL}" -gt 0 ] 2>/dev/null || return 0

        sleep "${MK_LOOP_INTERVAL}"

    done

}

[ -z "${MK_SOURCE_AGENT}" ] && main "$@"