yum

#!/bin/bash

if [ -z $MK_VARDIR ]; then
    echo "Unable to load ENV variables"
    exit 2
fi

BOOT_REQUIRED=no
UPDATES=0
SECURITY_UPDATES=0
CACHE_RESULT_CHECK=$MK_VARDIR/cache/yum_result.cache
CACHE_YUM_UPDATE=$MK_VARDIR/cache/yum_update.cache
CACHE_PREV_UPTIME=$MK_VARDIR/cache/yum_uptime.cache
LAST_UPDATE_TIMESTAMP=-1


# get current yum state - use cache directory contents as fingerprint
YUM_CURRENT="$(ls -lR /var/cache/{yum,dnf}/)"

# check if cached listing of /var/cache/yum already exists - create empty one otherwise
if [ ! -e $CACHE_YUM_UPDATE ]
then
    touch $CACHE_YUM_UPDATE
elif [ ! -f $CACHE_YUM_UPDATE ] || [ -L $CACHE_YUM_UPDATE ]
then
    # something is wrong here...
    echo "invalid cache file"
    exit 2
else
    # get cached information
    YUM_CACHED=$(cat "$CACHE_YUM_UPDATE")
fi

# check if cached check result already exists and is nothing but a file
if [ ! -e $CACHE_RESULT_CHECK  ]
then
    touch $CACHE_RESULT_CHECK
elif [ ! -f $CACHE_RESULT_CHECK ] || [ -L $CACHE_RESULT_CHECK ]
then
    # something is wrong here...
    echo "invalid cache file"
    exit 2
fi

# check if system has rebooted - if so, remove cached check file to avoid wrong "reboot required"-state
RUNNING_SECS=$(cat /proc/uptime | cut -d" " -f1 | cut -d"." -f1)

# check if cache file with previously seen uptime is existing - create one otherwise
if [ ! -e $CACHE_PREV_UPTIME ]
then
    echo 0 > $CACHE_PREV_UPTIME
    PREV_UPTIME=0
elif [ ! -f $CACHE_PREV_UPTIME ] || [ -L $CACHE_PREV_UPTIME ]
then
    # something is wrong here...
    echo "invalid cache file"
    exit 2
else
    # get cached information
    PREV_UPTIME=$(cat "$CACHE_PREV_UPTIME")
    # save current uptime
    echo $RUNNING_SECS > $CACHE_PREV_UPTIME
fi

# check if current uptime is lower than cached last seen uptime to detect reboot
if (( RUNNING_SECS < PREV_UPTIME ))
then
    # remove pre-reboot cache which requires reboot
    rm -f $CACHE_RESULT_CHECK
    # create empty check cache
    touch $CACHE_RESULT_CHECK
fi

echo "<<<yum>>>"

# compare current and cached yum information
# Update cached data if YUM fingerprint has changed OR machine has recently rebooted.
if [ "$YUM_CURRENT" != "$YUM_CACHED" ] || [ ! -s $CACHE_RESULT_CHECK ]
then
    count=0
        while [ -n "$(pgrep -f "python (/usr|)/bin/(yum|dnf)")" ]; do
            if [ $count -eq 3 ]; then
                echo "Tried to run yum for 30 secs but another yum instance was running"
                exit 2
            else
                ((count++))
                sleep 10
            fi
        done
    LATEST_KERNEL=$(yum -q -C --noplugins --debuglevel 0 list installed | egrep "^(vz)?kernel(|-(uek|ml|lt))\." | grep "\." | tail -n1 | awk '{print $2};')
    RUNNING_KERNEL=$(cat /proc/version | awk '{print $3}' | sed 's/.x86_64//g')
    if [[ "$RUNNING_KERNEL" == "$LATEST_KERNEL"* ]]
    then
        BOOT_REQUIRED="no"
    else
        BOOT_REQUIRED="yes"
    fi
    UPDATES=$(waitmax 25 /usr/bin/yum -C --noplugins --quiet list updates | grep "\." | cut -d' ' -f1 | wc -l || echo "-1")
    # check if --security is available
    waitmax 10 /usr/bin/yum -C --noplugins --quiet --security list updates > /dev/null 2>&1
    if [ $? -eq 0 ]
    then
        SECURITY_UPDATES=$(waitmax 25 /usr/bin/yum -C --noplugins --quiet --security list updates | grep "\." | cut -d' ' -f1 | wc -l || echo "-1")
    else
    # --security not supported with this yum version
    # maybe the yum-plugin-security package is needed (RH 6)
            SECURITY_UPDATES="-2"
    fi

    # Check last time of installed Updates from yum history
    LAST_UPDATE_TIMESTAMP=$(/usr/bin/yum -C --quiet --noplugins history | awk '{if(NR>2)print}' | grep  ' U \|Upgrade' | cut -d '|' -f3  | head -n 1 | date -f - +"%s" || echo "-1")


    echo $BOOT_REQUIRED
    echo $UPDATES
    echo $SECURITY_UPDATES
    echo $LAST_UPDATE_TIMESTAMP

    # cache check yum
    # check if cached check already exists and is nothing but a file
    if [ -f $CACHE_YUM_UPDATE ] || [ ! -L $CACHE_YUM_UPDATE ]; then
        echo "$YUM_CURRENT" > $CACHE_YUM_UPDATE
    else
        # something is wrong here...
        echo "invalid check cache file"
        exit 2
    fi
    # cache check results
    # check if cached check result already exists and is nothing but a file
    if [ -f $CACHE_RESULT_CHECK ] || [ ! -L $CACHE_RESULT_CHECK ]
    then
        echo $BOOT_REQUIRED > $CACHE_RESULT_CHECK
        echo $UPDATES >> $CACHE_RESULT_CHECK
        echo $SECURITY_UPDATES >> $CACHE_RESULT_CHECK
        echo $LAST_UPDATE_TIMESTAMP >> $CACHE_RESULT_CHECK
    else
        # something is wrong here...
        echo "invalid check result cache file"
        exit 2
    fi
else
    # use cache file
    cat $CACHE_RESULT_CHECK
fi