Passing variable in init.d script

Question

I have the init.d script show below.

I want to start the daemon with the argument

--http_root /tv

When I start the application without the daemon the argument is accepted

However I cannot seem to figure out how to adjust the script below to start the daemon with that argument. I want the argument to be passed every time

sudo service tvheadend start

is issued. I do not want to pass an argument to the init.d script.

How can I achieve that?

#! /bin/sh
### BEGIN INIT INFO
# Provides:          tvheadend
# Required-Start:    $local_fs $remote_fs udev
# Required-Stop:     $local_fs $remote_fs
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
### END INIT INFO

# Author: Andreas Öman

# Do NOT "set -e"

# PATH should only include /usr/* if it runs after the mountnfs.sh script
PATH=/usr/sbin:/usr/bin:/sbin:/bin
DESC="Tvheadend"
NAME=tvheadend
DAEMON=/usr/bin/$NAME
PIDFILE=/var/run/$NAME.pid
SCRIPTNAME=/etc/init.d/$NAME

# Exit if the package is not installed
[ -x "$DAEMON" ] || exit 0

# Read configuration variable file if it is present
[ -r /etc/default/$NAME ] && . /etc/default/$NAME

# Configure command line options
[ "$TVH_ENABLED" = "1" ] || exit 0

ARGS="-f"
[ -z "$TVH_USER"      ] || ARGS="$ARGS -u $TVH_USER"
[ -z "$TVH_GROUP"     ] || ARGS="$ARGS -g $TVH_GROUP"
[ -z "$TVH_CONF_DIR"  ] || ARGS="$ARGS -c $TVH_CONF_DIR"
[ -z "$TVH_ADAPTERS"  ] || ARGS="$ARGS -a $TVH_ADAPTERS"
[ "$TVH_IPV6" = "1"   ] && ARGS="$ARGS -6"
[ -z "$TVH_HTTP_PORT" ] || ARGS="$ARGS --http_port $TVH_HTTP_PORT"
[ -z "$TVH_HTTP_ROOT" ] || ARGS="$ARGS --http_root $TVH_HTTP_ROOT"
[ -z "$TVH_HTSP_PORT" ] || ARGS="$ARGS --htsp_port $TVH_HTSP_PORT"
[ -z "$TVH_ARGS"      ] || ARGS="$ARGS $TVH_ARGS"
[ "$TVH_DEBUG" = "1"  ] && ARGS="$ARGS -s"

# Load the VERBOSE setting and other rcS variables
[ -f /etc/default/rcS ] && . /etc/default/rcS

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.
. /lib/lsb/init-functions

#
# Function that starts the daemon/service
#
do_start()
{
    # Return
    #   0 if daemon has been started
    #   1 if daemon was already running
    #   2 if daemon could not be started
        udevadm settle
    start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON --test > /dev/null \
        || return 1
    start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON -- \
        $ARGS \
        || return 2
}

#
# Function that stops the daemon/service
#
do_stop()
{
    # Return
    #   0 if daemon has been stopped
    #   1 if daemon was already stopped
    #   2 if daemon could not be stopped
    #   other if a failure occurred
    start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile $PIDFILE --name $NAME
    RETVAL="$?"
    [ "$RETVAL" = 2 ] && return 2
    # Many daemons don't delete their pidfiles when they exit.
    rm -f $PIDFILE
    return "$RETVAL"
}


case "$1" in
  start)
    [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
    do_start
    case "$?" in
        0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;
  stop)
    [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
    do_stop
    case "$?" in
        0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;
  restart|force-reload)
    #
    # If the "reload" option is implemented then remove the
    # 'force-reload' alias
    #
    log_daemon_msg "Restarting $DESC" "$NAME"
    do_stop
    case "$?" in
      0|1)
        do_start
        case "$?" in
            0) log_end_msg 0 ;;
            1) log_end_msg 1 ;; # Old process is still running
            *) log_end_msg 1 ;; # Failed to start
        esac
        ;;
      *)
        # Failed to stop
        log_end_msg 1
        ;;
    esac
    ;;
  *)
    echo "Usage: $SCRIPTNAME {start|stop|restart|force-reload}" >&2
    exit 3
    ;;
esac

:

Solution

If you don't want to modify the init.d script, change (or create)

/etc/default/tvheadend

as steeldriver pointed out in his comment, edit (add, extend) the entry:

TVH_HTTP_ROOT=/tv

This file gets sourced in the init.d script, with this line:

[ -r /etc/default/$NAME ] && . /etc/default/$NAME

and then

[ -z "$TVH_HTTP_ROOT" ] || ARGS="$ARGS --http_root $TVH_HTTP_ROOT"

will set the argument to the daemon invocation.

Otherwise you can also just change the line.

ARGS="-f"

in the script to

ARGS="-f --http_root /tv"

But that gets overwritten on a package update.

Comments

[smw]

Is there any particular reason not to set the TVH_HTTP_ROOT variable directly, rather than modifying TVH_ARGS?

[Anthon]

I actually missed that that already provides the --http_root part (I haven't got this app installed myself), I'll update my answer.