#!/usr/bin/env sh

. /etc/log2ram.conf

LOG_NAME="log2ram.log"


isSafe () {
    [ -d $HDD_LOG/ ] || echo "ERROR: $HDD_LOG/ doesn't exist! Can't sync."
    [ -d $HDD_LOG/ ] || exit 1
}

syncToDisk () {
    isSafe
    
    if [ "$USE_RSYNC" = true ]; then
        rsync -aXv --inplace --no-whole-file --delete-after $RAM_LOG/ $HDD_LOG/ 2>&1 | tee -a $LOG2RAM_LOG
    else
        cp -rfup --preserve=context $RAM_LOG/ -T $HDD_LOG/ 2>&1 | tee -a $LOG2RAM_LOG
    fi
}

syncFromDisk () {
    isSafe
    
    TP_SIZE=$SIZE
    if [ "$ZL2R" = true ]; then
        TP_SIZE=$LOG_DISK_SIZE
    then
    
    if [ ! -z "$(du -sh -t "$TP_SIZE" $HDD_LOG/ | cut -f1)" ]; then
        echo "ERROR: RAM disk for "$HDD_LOG/" too small. Can't sync."
        umount -l $RAM_LOG/
        umount -l $HDD_LOG/
        if [ "$MAIL" = true ]; then
            echo "LOG2RAM : No place on RAM for "$HDD_LOG/" anymore, fallback on the disk" | mail -s 'Log2Ram Error' root;
        fi
        exit 1
    fi

    if [ "$USE_RSYNC" = true ]; then
        rsync -aXv --inplace --no-whole-file --delete-after $HDD_LOG/ $RAM_LOG/ 2>&1 | tee -a $LOG2RAM_LOG
    else
        cp -rfup --preserve=context $HDD_LOG/ -T $RAM_LOG/ 2>&1 | tee -a $LOG2RAM_LOG
    fi
}

wait_for () {
    while ! grep -qs "$1" /proc/mounts; do
        sleep 0.1
    done
}

createZramLogDrive () {
	# Check Zram Class created
	if [ ! -d "/sys/class/zram-control" ]; then
		modprobe zram
		RAM_DEV='0'
	else
		RAM_DEV=$(cat /sys/class/zram-control/hot_add)
	fi
	echo ${COMP_ALG} > /sys/block/zram${RAM_DEV}/comp_algorithm
	echo ${LOG_DISK_SIZE} > /sys/block/zram${RAM_DEV}/disksize
	echo ${SIZE} > /sys/block/zram${RAM_DEV}/mem_limit
	mke2fs -t ext4 /dev/zram${RAM_DEV}
}

case "$1" in
    start)
        IFS=';'
        for i in $PATH_DISK; do
            PATH_FIRST_PART=$( echo ${i%/*} )
            PATH_LAST_PART=$( echo ${i##/*/} )
            RAM_LOG=$i
            HDD_LOG=$PATH_FIRST_PART/hdd.$PATH_LAST_PART
            LOG2RAM_LOG="${RAM_LOG}/${LOG_NAME}"
        
            [ -d $HDD_LOG/ ] || mkdir $HDD_LOG/
            mount --bind $RAM_LOG/ $HDD_LOG/
            mount --make-private $HDD_LOG/
            wait_for $HDD_LOG
        
            if [ "$ZL2R" = true ]; then
                createZramLogDrive
                mount -t ext4 -o nosuid,noexec,nodev,user=log2ram /dev/zram${RAM_DEV} ${RAM_LOG}/
            else
                mount -t tmpfs -o nosuid,noexec,nodev,mode=0755,size=${SIZE} log2ram $RAM_LOG/
            fi
            wait_for $RAM_LOG
            syncFromDisk
        done
        ;;

    stop)
        IFS=';'
        for i in $PATH_DISK; do
            PATH_FIRST_PART=$( echo ${i%/*} )
            PATH_LAST_PART=$( echo ${i##/*/} )
            RAM_LOG=$i
            HDD_LOG=$PATH_FIRST_PART/hdd.$PATH_LAST_PART
            LOG2RAM_LOG="${RAM_LOG}/${LOG_NAME}"
            
            syncToDisk
            #ZRAM_LOG=$(awk '$2 == "/var/log" {print $1}' /proc/mounts)
            #ZRAM_LOG=$(echo ${ZRAM_LOG} | grep -o -E '[0-9]+')
            umount -l $RAM_LOG/
            umount -l $HDD_LOG/
            # Unsure as even with Root permision denied
            #echo ${ZRAM_LOG} > /sys/class/zram-control/hot_remove
        done
        ;;

    write)
        IFS=';'
        for i in $PATH_DISK; do
            PATH_FIRST_PART=$( echo ${i%/*} )
            PATH_LAST_PART=$( echo ${i##/*/} )
            RAM_LOG=$i
            HDD_LOG=$PATH_FIRST_PART/hdd.$PATH_LAST_PART
            LOG2RAM_LOG="${RAM_LOG}/${LOG_NAME}"
            
            syncToDisk
        done
        ;;

    *)
        echo "Usage: log2ram {start|stop|write}" >&2
        exit 1
        ;;
esac