Daemon - how to tell the start daemon to execute this daemon as different username than root?

Question

I have this startup script, when i launch i have the execution done by username: root, instead of username: sun.

How can i tell the start_daemon to execute it as username : sun not root?

$ ps aux | grep python
root       950  0.1  0.2 171132 18936 ?        S    05:35   0:00 /usr/bin/python /var/tmp/mp.py

root@nson:/etc/rc0.d# cat K20mp 
#! /bin/sh
PATH=/bin:/usr/bin:/sbin:/usr/sbin
DAEMON=/var/tmp/mp.sh
PIDFILE=/var/run/mp.pid

test -x $DAEMON || exit 0

. /lib/lsb/init-functions

case "$1" in
  start)
     log_daemon_msg "Starting mp"
     start_daemon -p $PIDFILE $DAEMON --user sun --chuid sun
     log_end_msg $?
   ;;
  stop)
     log_daemon_msg "Stopping mp"
     killproc -p $PIDFILE $DAEMON
     PID=`ps x |grep mp.py | head -1 | awk '{print $1}'`
     kill -9 $PID       
     log_end_msg $?
   ;;
  force-reload|restart)
     $0 stop
     $0 start
   ;;
  status)
     status_of_proc -p $PIDFILE $DAEMON atd && exit 0 || exit $?
   ;;
 *)
   echo "Usage: /etc/init.d/atd {start|stop|restart|force-reload|status}"
   exit 1
  ;;
esac
exit 0

EDIT: Reference not working

http://man.he.net/man8/start-stop-daemon

http://refspecs.linuxbase.org/LSB_3.1.1/LSB-Core-generic/LSB-Core-generic/iniscrptfunc.html

Solution

--user and --chuid works but has to be used with start-stop-daemon.

Example: As root user if now execute: /etc/init.d/PythonGUI start it execute as username: sun

#! /bin/sh
PATH=/sbin:/usr/sbin:/bin:/usr/bin
DESC="Python GUI - Server"
NAME=PythonGUI.sh
DAEMON=/var/tmp/$NAME
DAEMON_ARGS="--options args"
PIDFILE=/var/run/$NAME.pid
SCRIPTNAME=/etc/init.d/PythonGUI

[ -x "$DAEMON" ] || exit 0
[ -r /etc/default/$NAME ] && . /etc/default/$NAME
. /lib/init/vars.sh
. /lib/lsb/init-functions

do_start() {
    start-stop-daemon --start --quiet --user sun --pidfile $PIDFILE --chuid sun --exec $DAEMON --test > /dev/null \
        || return 1
    start-stop-daemon --start --quiet --user sun --pidfile $PIDFILE --chuid sun --exec $DAEMON -- \
        $DAEMON_ARGS \
        || return 2
}

do_stop() {
    start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile $PIDFILE --name $NAME
    RETVAL="$?"
    [ "$RETVAL" = 2 ] && return 2
    start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec $DAEMON
    [ "$?" = 2 ] && return 2    
    rm -f $PIDFILE
    return "$RETVAL"
}

do_reload() {
    start-stop-daemon --stop --signal 1 --quiet --pidfile $PIDFILE --name $NAME
    return 0
}

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) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;
  status)
    status_of_proc "$DAEMON" "$NAME" && exit 0 || exit $?
    ;;
  restart|force-reload)
    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
        ;;
      *)
        log_end_msg 1
        ;;
    esac
    ;;
  *)
    echo "Usage: $SCRIPTNAME {start|stop|status|restart|force-reload}" >&2
    exit 3
    ;;
esac
:

EDIT:

update-rc.d apache2 start 20 2 3 4 . start 30 5 . stop 80 0 1 6 .

• priority 20 (it can be 30, 80 etc)
• runlevels for start / stop

Runlevels are logical groups of tasks. Traditionally you have five run levels.

0 boot
1 single user 
2 not used
3 multiuser
4 not used 
5 gui
6 reboot 

Comments

[Danila Ladner]

which OS are you trying to run this on?

[Hauke Laging]

Doesn't the service start at all or does it start but run as root? Does the user sun exist (id sun)?

[Admin]

service starts fine. but the problem is it start as root. it needs to be started as username: sun (# id -u sun 1000 )

[Danila Ladner]

Can you paste from your OS "/etc/rc.d/init.d/functions" for me please?

[Admin]

Its working now see my Answer section. Thank you