svectl

#!/bin/sh

TEMPLATE_DIR="/opt/victronenergy/service-templates"
SERVICE_DIR="/run/service"
PERMANENT_SERVICE_DIR="/opt/victronenergy/service"
CONFIG_DIR="$TEMPLATE_DIR/conf"

usage() {
    echo "$0 -- install or remove services on a Venus Device."
    echo
    echo "Services on Venus are typically supervised by daemontools. For devices which are"
    echo "discovered later these service can be created once found. Typically they need some"
    echo "parameter to be change, e.g. the tty or network interface. This script reads which"
    echo "parameters to change from /opt/victronenergy/service-templates/conf and creates"
    echo "the corresponding service from /opt/victronenergy/service-templates/[service] in"
    echo "/run/service after changing the parameters. Optionally it can be created in the"
    echo "rootfs as well, so it will survive a reboot, but in normal cases the rootfs is"
    echo "readonly."
    echo
    echo "Options:"
    echo "-D var=value  set service dependend parameters"
    echo "-h            this help"
    echo "-l            list the avialable services"
    echo "-p            permanently install the service in the rootfs as well."
    echo "              This requires a writable rootfs!"
    echo "-r            remove the service"
    echo "-s            the service to be installed, see -l"
    echo "-t            the template dir to be used, /opt/victronenergy/service-templates by default"
    echo "-w            wait for a service dir to be supervised when adding a service"
    echo
    exit
}

error() {
    printf "%s\n" "$*" >&2
    exit 1
}

# Checks if the first sentence contains the word passed as second argument.
# returns 0 if that is the case, 1 otherwise.
contains() {
    for word in $1; do
        if [ "$word" = "$2" ]; then
            return 0
        fi
    done

    return 1
}

reset_config() {
    PARAMS=""
    PARAM_HELP=""
    SERVICE_EXT=""
}

parse_config_file() {
    local file
    file="$1"

    if [ ! -f "$file" ]; then
        error "The config file $file doesn't exists"
    fi

    local config
    config="$(sed -e 's/#.*//' -e '/^[[:space:]]*$/d' -e 's/[[:space:]]*=[[:space:]]*/=/' "${file}")"

	# read will succesfully read an empty variable, prevent that.
    if [ "$config" = "" ]; then
        return
    fi

    while read -r line; do
        firstword="${line%% *}"
        case "$firstword" in
            # instructions
            include)
                inc="$CONFIG_DIR/${line#* }"
                if contains "$INCLUDED" "$inc"; then
                    error "$inc is included multiple times!"
                fi
                INCLUDED="${INCLUDED} $inc"
                parse_config_file "$inc"
                ;;

            # assumed to be variables
            *)
                # split in var=value
                var="${line%%=*}"
                value="${line#*=}"

                case "$var" in
                    "PARAM")
                        param="${value%%:*}"
                        PARAMS="${PARAMS} $param"
                        PARAM_HELP="${PARAM_HELP}$value\n"
                    ;;
                    "SERVICE_EXT")
                        SERVICE_EXT="$value"
                    ;;
                    *)
                        error "unknown config option $var in $file"
                    ;;
                esac
                ;;
        esac

    done <<EOF
        $config
EOF
}

parse_config() {
    reset_config
    parse_config_file "$1"
}

create_service_dir() {
    src="$1"
    tg="$2"
    subst="$3"

    # check if service already exists
    test -d "$tg" && return 0

    # copy service template
    if ! mkdir -p "$tg"; then
        return 1
    fi
    cp -a "$src/." "$tg"

    # patch run files for CAN-bus device
    cmd="sed -i $subst '$tg/run'" && eval "$cmd"
    cmd="sed -i $subst '$tg/log/run'" && eval "$cmd"
}

check_supervise() {
    sv="$1"

    for i in {1..70}; do
        sleep 0.1
        if [ -e "$sv/supervise/control" ] && [ -e "$sv/log/supervise/control" ]; then
            return 0
        fi
    done

    return 1
}

# substitute nothing by default
subst="-e ''"
permanent=0
action="add"
wait=0

while getopts "h:D:lprs:t:w" arg; do
    case $arg in
        h)
            usage
            ;;
        D)
            var="${OPTARG%=*}"
            value="${OPTARG#*=}"
            subst="$subst -e 's:$var:$value:'"
            vars="$vars $var"
            ;;
        l)
            echo "Available services:"
            for service in $(find /opt/victronenergy/service-templates/conf/ -name "*.conf" -exec sh -c 'f="$1"; basename "$f" .conf' dummy {} \; | sort); do
                echo " - $service"
            done
            exit
            ;;
        p)
            permanent=1
            ;;
        r)
            action="remove"
            ;;
        s)
            service=$OPTARG
            ;;
        t)
            TEMPLATE_DIR="$OPTARG"
            ;;
        w)
            wait=1
            ;;
    esac
done

if [ -z "$service" ]; then
    echo "Service is not set, see -s"
    usage
fi

src="$TEMPLATE_DIR/$service"
if [ ! -d "$src" ]; then
    error "The template directory $src doesn't exist"
fi

config="${CONFIG_DIR}/$service.conf"
parse_config "${config}"

# make sure all additional variables are set.
for arg in $PARAMS; do
    if ! contains "$vars" "$arg" ; then
        echo "$arg is needed, but is not defined, -D $arg=..."
        exit 1
    fi
done

# make sure no garbage is set.
for var in $vars; do
    if ! contains "$PARAMS" "$var" ; then
        echo "$var is defined, but is not valid"
        exit 1
    fi
done

cmd="echo $SERVICE_EXT | sed $subst"
service_dir="$service$(eval "$cmd")"
tg="$SERVICE_DIR/$service_dir"
svc="/service/$service_dir"
perm="${PERMANENT_SERVICE_DIR}/$service_dir"

case $action in

    "add")
        # By default only a service is created on the RAM-disk, since Venus OS uses a readonly
        # rootfs. After a reboot, they are no longer present and will be re-added by serial-starter,
        # venus-platform etc. This option will add them permanently, but that does require a
        # writable rootfs.
        if [ $permanent -eq 1 ]; then
            echo "Adding permanent service: $perm"
            if ! create_service_dir "$src" "$perm" "$subst" 2>/dev/null; then
                error "Adding permanent service failed. Forgot to run /opt/victronenergy/swupdate-scripts/resize2fs.sh ?"
            fi
        fi

        # The RAM-disk service
        echo "Adding runtime service: $tg"
        create_service_dir "$src" "$tg" "$subst"

        # symlink into /service for svscan to find
        echo "Adding svc service (symlink): $svc"
        ln -sf "$tg" "$svc"

        if [ -e "$svc/down" ]; then
            echo "NOTE: the service ($svc) is still down."
        fi

        # This is venus specific, with a stock daemontools, this can take up to 5 seconds.
        # In venus daemontools is patched, so it can be signalled to scan. Since svscan
        # will be killed in an unpatched case, make sure to only signal it when supported.
        if which svrescan; then
            svrescan
        fi

        if [ $wait -eq 1 ]; then
            check_supervise "$svc"
        fi
        ;;

    "remove")
        [ -e "$svc" ] && echo "Removing svc service $svc" && rm -rf "$svc"
        [ -e "$tg" ] && echo "Stopping: $tg" && svc -dx "$tg" "$tg/log"
        [ -e "$tg" ] && echo "Removing runtime service: $tg" && rm -rf "$tg"
        [ -e "$perm" ] && echo "Removing permanent service: $perm" && rm -rf "$perm"
        exit 0
        ;;

esac