#!/usr/bin/ksh93
# 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.

# Reason for this no-op: shellcheck disable=... before the first command disables the error for the
# entire script.
:

# Disable unused variable error (needed to keep track of version)
# shellcheck disable=SC2034
CMK_VERSION="2.3.0p38"

# Monitor DB/2 databases on AIX
# $HOME/sqllib/db2profile

# This script can be called in two ways
# Without any arguments:
#   Checks if cache of the instances is up to date and starts the
#   command 'mk_db.aix query {instance}' if applicable
#   If its outdated the script calls itself with the argument 'query'
# With 'query {instance}' as argument:
#   Does the actual queries to the db2 instance and writes this info
#   into the cache file
# Each instance has its own cache file and all of them are filled in parallel

if [ ! "$MK_CONFDIR" ]; then
    echo "MK_CONFDIR not set!" >&2
    exit 1
fi

if [ ! "$MK_VARDIR" ]; then
    export MK_VARDIR=$MK_CONFDIR
fi

function waitmax {
    TIMEOUT=${1}0
    shift

    # Run command in background
    if [ "${#}" -ge 1 ]; then
        ksh -c "$*" &
    else
        TEST=$(cat)
        ksh -c "$TEST" &
    fi

    PID=$!

    # Wait for termination within TIMOUT seconds
    while [ "$TIMEOUT" -gt 0 ]; do
        TIMEOUT=$((TIMEOUT - 1))
        if [ ! -e /proc/$PID ]; then
            return 0
        fi
        perl -e "select(undef, undef, undef, 0.1);"
    done

    # Process did not terminate in time. Kill and
    # return with an error
    kill -9 $PID
    return 255
}

function query_instance {
    INSTANCE=$1
    # find home directory
    HOMEDIR=$(grep -w "^$INSTANCE:" /etc/passwd | awk -F: '{print $6}')
    NOW=$(perl -e "print time();")

    waitmax 200 <<WAITMAX
    su - $INSTANCE -c "/usr/bin/ksh93" << EOF

    if [ ! -f $HOMEDIR/sqllib/db2profile ] ;
    then
        exit 0
    fi

    . $HOMEDIR/sqllib/db2profile >/dev/null 2>&1 ;


    function compare_version_greater_equal {
        GREATER_ONE=\\\$(echo "\\\$1 \\\$2" | awk "{if (\\\$1 >= \\\$2) print \\\$1; else print \\\$2}")
        if [ \\\$GREATER_ONE == \\\$1 ] ; then
            return 0
        else
           return 1
        fi
    }

    echo '<<<db2_version:sep(1)>>>'
    DBVERSION=\\\$(db2 get snapshot for dbm | grep -e 'Product name' -e 'Service level' | awk -v FS='=' '{print \\\$2}' | sed 'N;s/\n/,/g' | sed 's/ //g')
    echo $INSTANCE \\\$DBVERSION
    VERSION_NUMBER=\\\$(echo \\\$DBVERSION | sed  -e 's/DB2v\\\(.*\),.*/\\\1/' | awk -v FS="." '{print \\\$1"."\\\$2}')

    DBS=\\\$(db2 list database directory on $HOMEDIR | grep 'Database name' | awk '{ print \\\$NF }')

    GET_PORT=1
    DB_PORT='port 0'
    for DB in \\\$DBS; do
            db2 connect to \\\$DB > /dev/null;
            if [ $? -ne 0 ] ; then
                exit 1
            fi

            if [ 1 -eq \\\$GET_PORT ] ; then
                # Each database in an instance has the same port information
                db2_tcp_service=\\\$(db2 -x get dbm cfg | grep $INSTANCE | grep "TCP/IP Service" | awk -v FS='=' '{print \\\$2}'|tr -d ' ')
                if ( grep \\\$db2_tcp_service /etc/services | grep -q "^\\\$db2_tcp_service " ); then
                    DB_PORT='port '\\\$(grep \\\$db2_tcp_service /etc/services | grep "^\\\$db2_tcp_service " | awk '{print \\\$2}' | awk -v FS="/" '{print \\\$1}')
                fi
                GET_PORT=0
            fi

            echo "<<<db2_tablespaces>>>"
            echo "[[[$INSTANCE:\\\$DB]]]"
            db2 "SELECT tbsp_name, tbsp_type, tbsp_state, tbsp_usable_size_kb, tbsp_total_size_kb, tbsp_used_size_kb, tbsp_free_size_kb FROM sysibmadm.tbsp_utilization WHERE tbsp_type = 'DMS' UNION ALL SELECT tu.tbsp_name, tu.tbsp_type, tu.tbsp_state, tu.tbsp_usable_size_kb, tu.tbsp_total_size_kb, tu.tbsp_used_size_kb, (cu.fs_total_size_kb - cu.fs_used_size_kb) AS tbsp_free_size_kb FROM sysibmadm.tbsp_utilization tu INNER JOIN ( SELECT tbsp_id, 1 AS fs_total_size_kb, 0 AS fs_used_size_kb FROM sysibmadm.container_utilization WHERE (fs_total_size_kb IS NULL OR fs_used_size_kb IS NULL) GROUP BY tbsp_id) cu ON (tu.tbsp_type = 'SMS' AND tu.tbsp_id = cu.tbsp_id) UNION ALL SELECT tu.tbsp_name, tu.tbsp_type, tu.tbsp_state, tu.tbsp_usable_size_kb, tu.tbsp_total_size_kb, tu.tbsp_used_size_kb, (cu.fs_total_size_kb - cu.fs_used_size_kb) AS tbsp_free_size_kb FROM sysibmadm.tbsp_utilization tu INNER JOIN ( SELECT tbsp_id, SUM(fs_total_size_kb) AS fs_total_size_kb, SUM(fs_used_size_kb) AS fs_used_size_kb FROM sysibmadm.container_utilization WHERE (fs_total_size_kb IS NOT NULL AND fs_used_size_kb IS NOT NULL) GROUP BY tbsp_id) cu ON (tu.tbsp_type = 'SMS' AND tu.tbsp_id = cu.tbsp_id)" | awk '{print \\\$1" "\\\$2" "\\\$3" "\\\$4" "\\\$5" "\\\$6" "\\\$7}' | sed -e '/^[ ]*$/d' -e '/^-/d' -e '/selected/d'

            echo "<<<db2_counters>>>"
            echo "TIMESTAMP $NOW"
            cat \\\$(db2 get dbm cfg|grep "Default database path"|awk -v FS="=" '{print \\\$2"/sqllib/db2nodes.cfg"}'|tr -d ' ') | sed "s/\(.*\)/$INSTANCE:\\\$DB node \1/"
            db2 -x "SELECT deadlocks from sysibmadm.snapdb" | tr -d ' ' | sed "s/\(.*\)/$INSTANCE:\\\$DB deadlocks \1/"
            db2 -x "SELECT lock_waits from sysibmadm.snapdb" | tr -d ' ' | sed "s/\(.*\)/$INSTANCE:\\\$DB lockwaits \1/"
            db2 -x "SELECT sort_overflows from sysibmadm.snapdb" | tr -d ' ' | sed "s/\(.*\)/$INSTANCE:\\\$DB sortoverflows \1/"

            echo "<<<db2_logsizes>>>"
            echo "[[[$INSTANCE:\\\$DB]]]"
            echo "TIMESTAMP $NOW"
            cat \\\$(db2 get dbm cfg|grep "Default database path"|awk -v FS="=" '{print \\\$2"/sqllib/db2nodes.cfg"}'|tr -d ' ') | sed 's/\(.*\)/node \1/'
            db2 -x "SELECT 'usedspace', total_log_used from sysibmadm.snapdb" | awk '{print \\\$1" "\\\$2}'
            db2 -x "SELECT NAME, VALUE FROM SYSIBMADM.DBCFG WHERE NAME IN ('logfilsiz','logprimary','logsecond')"| awk '{print \\\$1" "\\\$2}'

            echo "<<<db2_connections>>>"
            echo "[[[$INSTANCE:\\\$DB]]]"
            echo \\\$DB_PORT
            echo "connections " | tr -d '\n'
            db2 list applications | grep -v Auth | grep -v Name | sed -e '/^$/d' | wc -l | tr -d ' '
            # TODO: the time command seems to be broken and outputs 1 second steps
            ksh -c "time db2 connect to \\\$DB > /dev/null" 2>&1 | grep real | awk '{print "latency "\\\$2}'| sed -e 's/m/:/' -e 's/s//'

            echo "<<<db2_bp_hitratios>>>"
            echo "[[[$INSTANCE:\\\$DB]]]"
            cat \\\$(db2 get dbm cfg|grep "Default database path"|awk -v FS="=" '{print \\\$2"/sqllib/db2nodes.cfg"}'|tr -d ' ') | sed "s/\(.*\)/node \1/"
            db2 "SELECT SUBSTR(BP_NAME,1,14) AS BP_NAME, TOTAL_HIT_RATIO_PERCENT, DATA_HIT_RATIO_PERCENT, INDEX_HIT_RATIO_PERCENT, XDA_HIT_RATIO_PERCENT FROM SYSIBMADM.BP_HITRATIO" | grep -v "selected." | sed -e '/^$/d' -e '/^-/d'

            echo "<<<db2_sort_overflow>>>"
            echo "[[[$INSTANCE:\\\$DB]]]"
            db2 -x "get snapshot for database on \\\$DB" | grep -e "^Total sorts" -e "^Sort overflows" | tr -d '='

            echo "<<<db2_backup>>>"
            echo "[[[$INSTANCE:\\\$DB]]]"
            if compare_version_greater_equal \\\$VERSION_NUMBER 10.5; then
                # MON_GET_DATBASE(-2) gets information of all active members
                db2 -x "select LAST_BACKUP from TABLE (MON_GET_DATABASE(-2))" | grep -v "selected." | tail -n 1
            else
                db2 -x "select SQLM_ELM_LAST_BACKUP from table(SNAPSHOT_DATABASE( cast( null as VARCHAR(255)), cast(null as int))) as ref" | grep -v "selected." | tail -n 1
            fi

            # disconnect from database
            db2 connect reset > /dev/null
        done
EOF
WAITMAX
    return $?
}

if [ "$1" = "query" ]; then
    query_instance "$2"
    exit $?
else
    #### RUN CACHED #####
    function file_age {
        /usr/bin/perl -e 'if (! -f $ARGV[0]){die "0000000"};$mtime=(stat($ARGV[0]))[9];print ($^T-$mtime);' "$1"
    }

    if [ ! -d "$MK_VARDIR/cache" ]; then mkdir -p "$MK_VARDIR/cache"; fi

    if [ -e "$MK_VARDIR/cache/mk_db2.aix.cache" ]; then
        rm "$MK_VARDIR/cache/mk_db2.aix.cache"
    fi
    INSTANCES=$(ps -ef | grep "[d]b2sysc" | awk '{print $1 }')

    # Output any section headers
    # If no data is available there will be at least the section headers
    # This happens when a database is down. In this scenario the db2_version check
    # should go CRIT and the other checks go stale
    echo "<<<db2_version:sep(1)>>>"
    echo "<<<db2_tablespaces>>>"
    echo "<<<db2_counters>>>"
    echo "<<<db2_logsizes>>>"
    echo "<<<db2_connections>>>"
    echo "<<<db2_bp_hitratios>>>"
    echo "<<<db2_sort_overflow>>>"
    echo "<<<db2_backup>>>"

    for INSTANCE in $INSTANCES; do
        CACHEFILE="$MK_VARDIR/cache/mk_db2.aix.cache.$INSTANCE"
        MAXAGE=300

        # Check if the creation of the cache takes way to long and delete this file
        # The process might have crashed...
        # Since the processes are called with waitmax it is very unlikely that
        # there are still unwanted processes soiling the system.
        if [ -e "$CACHEFILE.new" ]; then
            AGE=$(file_age "$CACHEFILE.new")
            if [ "$AGE" -ge $((MAXAGE * 10)) ]; then
                rm "$CACHEFILE.new"
            fi
        fi

        # Check if the creation of the cache takes suspiciously long and return
        # nothing if the age (access time) of $CACHEFILE.new is twice the MAXAGE
        if [ -e "$CACHEFILE.new" ]; then
            AGE=$(file_age "$CACHEFILE.new")
            if [ "$AGE" -ge $((MAXAGE * 2)) ]; then
                return
            fi
        fi

        # Check if cache file exists and is recent enough
        USE_CACHEFILE=""
        if [ -s "$CACHEFILE" ]; then
            AGE=$(file_age "$CACHEFILE")
            if [ "$AGE" -le $MAXAGE ]; then USE_CACHEFILE=1; fi
            # Output the file in any case, even if it is
            # outdated. The new file will not yet be available
            cat "$CACHEFILE"
        fi

        # Cache file outdated and new job not yet running? Start it
        if [ -z "$USE_CACHEFILE" ] && [ ! -e "$CACHEFILE.new" ]; then
            echo "set -o noclobber ; exec > \"$CACHEFILE.new\" || exit 1 ; ./$0 query $INSTANCE && mv \"$CACHEFILE.new\" \"$CACHEFILE\" || rm -f \"$CACHEFILE\" \"$CACHEFILE.new\"" | nohup ksh 2>/dev/null &
        fi

    done

fi

exit 0