mdevctl.libexec

#!/usr/bin/bash

persist_base=/etc/mdevctl.d
mdev_base=/sys/bus/mdev/devices
parent_base=/sys/class/mdev_bus
defaults=/etc/mdevctl.conf

declare -A config
config=([start]="auto")

read_config() {
    if [ -s ${1} ]; then
        while read line; do
            if echo $line | grep -F = &>/dev/null; then
                varname=$(echo "$line" | cut -d '=' -f 1)
                config[$varname]=$(echo "$line" | cut -d '=' -f 2-)
            fi
        done < ${1}
    fi
}

read_config $defaults

valid_uuid () {
    if [[ $1 =~ ^\{?[A-F0-9a-f]{8}-[A-F0-9a-f]{4}-[A-F0-9a-f]{4}-[A-F0-9a-f]{4}-[A-F0-9a-f]{12}\}?$ ]]; then
        echo $1
    fi
}

# The mdev device shows up before the link back to the type, wait for it
wait_for_mdev_type () {
    for i in $(seq 1 10); do
        if [ -L $mdev_base/$1/mdev_type ]; then
            break;
        fi
        sleep 0.5
    done
    if [ -L $mdev_base/$1/mdev_type ]; then
        readlink -f $mdev_base/$1/mdev_type
    fi
}

# udev can trigger start-mdev when the parent appears, give it some time
# to register with mdev
wait_for_supported_types () {
    for i in $(seq 1 10); do
        if [ -d $parent_base/$1/mdev_supported_types ]; then
            break;
        fi
        sleep 0.5
    done
    if [ -d $parent_base/$1/mdev_supported_types ]; then
        echo "$parent_base/$1/mdev_supported_types"
    fi
}

case ${1} in
    start-mdev|stop-mdev)
        if [ $# -ne 2 ]; then
            echo "Usage: $0 $1 <mdev UUID>" >&2
            exit 1
        fi
        cmd=$1
        uuid=$2
        ;;
    add-mdev)
        if [ $# -ne 2 ]; then
            echo "Usage: $0 $1 <mdev UUID>" >&2
            exit 1
        fi
        cmd=$1
        uuid=$2
        ;;
    get-mdevs)
        if [ $# -ne 2 ]; then
            echo "Usage: $0 $1 <parent device>" >&2
            exit 1
        fi
        cmd=$1
        parent=$2
        ;;
    *)
        echo "Unknown option $1" >&2
        exit 1
esac

case ${cmd} in
    stop-mdev)
        if [ -z "$(valid_uuid $uuid)" ]; then
            echo "Invalid UUID $uuid" >&2
            exit 1
        fi

        if [ ! -L $mdev_base/$uuid ]; then
            echo "No device named $uuid found" >&2
            exit 1
        fi

        echo 1 > $mdev_base/$uuid/remove
        if [ $? -ne 0 ]; then
            echo "Error removin device $uuid" >&2
            exit 1
        fi
        ;;

    start-mdev)
        if [ -z "$(valid_uuid $uuid)" ]; then
            echo "Invalid UUID $uuid" >&2
            exit 1
        fi

        if [ -L $mdev_base/$uuid ]; then
            echo "Device $uuid already exists" >&2
            exit 1
        fi

        file=$(find $persist_base -name $uuid -type f)
        if [ -z "$file" ]; then
            echo "No configuration found for $uuid" >&2
            exit 1
        fi

        read_config $file
        if [ -z "${config[mdev_type]}" ]; then
            echo "Invalid configuration for $uuid, no mdev_type" >&2
            exit 1
        fi
        parent=$(basename $(echo $file | sed -s "s/\/$uuid//"))
        supported_types=$(wait_for_supported_types $parent)
        if [ -z "$supported_types" ]; then
            echo "Parent $parent not enabled for mdev" >&2
            exit 1
        fi

        if [ ! -d $supported_types/${config[mdev_type]} ]; then
            echo "Parent $parent does not support mdev type ${config[mdev_type]}" >&2
            exit 1
        fi

        avail=$(cat $supported_types/${config[mdev_type]}/available_instances)
        if [ $? -ne 0 ] || [ $avail -eq 0 ]; then
            echo "No available instances of ${config[mdev_type]} on $parent" >&2
            exit 1
        fi

        echo $uuid > $supported_types/${config[mdev_type]}/create
        if [ $? -ne 0 ]; then
            echo "Error creating mdev type ${config[mdev_type]} on $parent" >&2
            exit 1
        fi
        ;;

    add-mdev)
        if [ -z "$(valid_uuid $uuid)" ]; then
            echo "Invalid UUID $uuid" >&2
            exit 1
        fi

        parent_type=$(wait_for_mdev_type $uuid)
        if [ -z "$parent_type" ]; then
            echo "Type of device $uuid unavailable" >&2
            exit 1
        fi

        mdev_type=$(basename $parent_type)
        parent=$(basename $(echo $parent_type | sed -e 's/\/mdev_supported_types.*//'))

        file=$(find $persist_base -name $uuid -type f)
        if [ -n "$file" ]; then
            if [ $file == $persist_base/$parent/$uuid ]; then
                orig=${config[start]}
                read_config $file
                if [  ${config[mdev_type]} != $mdev_type ]; then
                    config[start]=$orig
                    rm -f $file
                fi
            else
                rm -f $file
            fi
        fi

        if [ -z "$file" ] || [ ! -e $file ]; then
            if [ ! -d $persist_base/$parent ]; then
                mkdir -p $persist_base/$parent
            fi
            echo "mdev_type=$mdev_type" > $persist_base/$parent/$uuid
            echo "start=${config[start]}" >> $persist_base/$parent/$uuid
        fi
        ;;

    get-mdevs)
        if [ ! -d $persist_base/$parent ]; then
          exit 1
        fi

        for file in $(find $persist_base/$parent/ -maxdepth 1 -mindepth 1 -type f); do
            uuid=$(basename $file)
            if [ -n "$(valid_uuid $uuid)" ]; then
                orig=${config[start]}
                read_config $file
                if [ ${config[start]} == "auto" ]; then
                    result+="mdev@$uuid.service "
                fi
                config[start]=$orig
            fi
        done

        if [ -z "$result" ]; then
            exit 1
        fi

        echo $result
        ;;
esac