#!/bin/bash
# ext_check start <dev> <id> <options>
# ext_check status <dev> <id>
# ext_check cancel <dev> <id>

# Exit codes:
# 0 - No corruption detected or process not found.
# 1 - Corruption detected.
# 4 - File system corruption fixed.
# 8 - No check has been run yet.
# 9 - Process is still running.

# Using /var/lib because that's where btrfs puts status
mkdir -p /var/lib/ext

case "$1" in
'start')
    # Start the e2fsck process in the background and log output
    rm -f /var/lib/ext/check.status.$3
    {
        /sbin/e2fsck $4 $2 &> /var/lib/ext/check.status.$3
        echo $? > /var/lib/ext/check.status.$3.exit
    } > /dev/null 2>&1 &
    echo $! > /var/lib/ext/check.pid.$3
    exit 0
    ;;

'status')
    # Check if the process is still running
    if [ -f /var/lib/ext/check.pid.$3 ]; then
        pid=$(cat /var/lib/ext/check.pid.$3)
        if kill -0 $pid 2>/dev/null; then
            # Process is running, return status and exit code 9
            cat /var/lib/ext/check.status.$3
            exit 9
        else
            # Process is not running, read the exit status if available
            if [ -f /var/lib/ext/check.status.$3.exit ]; then
                exit_status=$(cat /var/lib/ext/check.status.$3.exit)
                cat /var/lib/ext/check.status.$3
                rm -f /var/lib/ext/check.pid.$3
    		(( exit_status & 1 )) && exit 4
    		(( exit_status & 4 )) && exit 1
		exit 0
            else
                # Exit status file does not exist, but return status file if available
                if [ -f /var/lib/ext/check.status.$3 ]; then
                    cat /var/lib/ext/check.status.$3
                fi
                exit 8
            fi
        fi
    else
        # No PID file found, check for existing status
        if [ -f /var/lib/ext/check.status.$3 ]; then
            cat /var/lib/ext/check.status.$3
            # If no exit status file, assume process completed successfully
            if [ -f /var/lib/ext/check.status.$3.exit ]; then
                exit_status=$(cat /var/lib/ext/check.status.$3.exit)
    		(( exit_status & 1 )) && exit 4
    		(( exit_status & 4 )) && exit 1
                exit 0
            else
                exit 8
            fi
        else
            # No status file found
            echo "Not available"
            exit 8
        fi
    fi
    ;;

'cancel')
    # Cancel the e2fsck process
    if [ -f /var/lib/ext/check.pid.$3 ]; then
        pid=$(cat /var/lib/ext/check.pid.$3)
        kill $pid
        while kill -0 $pid 2>/dev/null; do
            sleep 1
        done
        echo -e "\nCancelled" >> /var/lib/ext/check.status.$3
        rm -f /var/lib/ext/check.pid.$3
    else
        echo "No process to cancel"
    fi

    exit 0
    ;;

*)
    # Handle invalid commands
    echo "Invalid command"
    exit 0
    ;;
esac