ubuntu12.04 Daemon的简单实现

使用命令 start-stop-daemon

官方文档：http://manpages.ubuntu.com/manpages/lucid/en/man8/start-stop-daemon.8.html

Usage: start-stop-daemon [<option> ...] <command>

Commands:
  -S|--start -- <argument> ...  start a program and pass <arguments> to it
  -K|--stop                     stop a program
  -T|--status                   get the program status
  -H|--help                     print help information
  -V|--version                  print version

Matching options (at least one is required):
  -p|--pidfile <pid-file>       pid file to check
  -x|--exec <executable>        program to start/check if it is running
  -n|--name <process-name>      process name to check
  -u|--user <username|uid>      process owner to check

Options:
  -g|--group <group|gid>        run process as this group
  -c|--chuid <name|uid[:group|gid]>
                                change to this user/group before starting
                                  process
  -s|--signal <signal>          signal to send (default TERM)
  -a|--startas <pathname>       program to start (default is <executable>)
  -r|--chroot <directory>       chroot to <directory> before starting
  -d|--chdir <directory>        change to <directory> (default is /)
  -N|--nicelevel <incr>         add incr to the process' nice level
  -P|--procsched <policy[:prio]>
                                use <policy> with <prio> for the kernel
                                  process scheduler (default prio is 0)
  -I|--iosched <class[:prio]>   use <class> with <prio> to set the IO
                                  scheduler (default prio is 4)
  -k|--umask <mask>             change the umask to <mask> before starting
  -b|--background               force the process to detach
  -m|--make-pidfile             create the pidfile before starting
  -R|--retry <schedule>         check whether processes die, and retry
  -t|--test                     test mode, don't do anything
  -o|--oknodo                   exit status 0 (not 1) if nothing done
  -q|--quiet                    be more quiet
  -v|--verbose                  be more verbose

Retry <schedule> is <item>|/<item>/... where <item> is one of
 -<signal-num>|[-]<signal-name>  send that signal
 <timeout>                       wait that many seconds
 forever                         repeat remainder forever
or <schedule> may be just <timeout>, meaning <signal>/<timeout>/KILL/<timeout>

The process scheduler <policy> can be one of:
  other, fifo or rr

The IO scheduler <class> can be one of:
  real-time, best-effort or idle

Exit status:
  0 = done
  1 = nothing done (=> 0 if --oknodo)
  2 = with --retry, processes would not die
  3 = trouble
Exit status with --status:
  0 = program is running
  1 = program is not running and the pid file exists
  3 = program is not running
  4 = unable to determine status

　　

demo：

odoo的启动脚本

#!/bin/sh

### BEGIN INIT INFO
# Provides:             openerp-server
# Required-Start:       $remote_fs $syslog
# Required-Stop:        $remote_fs $syslog
# Should-Start:         $network
# Should-Stop:          $network
# Default-Start:        2 3 4 5
# Default-Stop:         0 1 6
# Short-Description:    Enterprise Resource Management software
# Description:          Open ERP is a complete ERP and CRM software.
### END INIT INFO

PATH=/bin:/sbin:/usr/bin
DAEMON=/opt/openerp/server/openerp-server
NAME=openerp-server
DESC=openerp-server

# Specify the user name (Default: openerp).
USER=openerp

# Specify an alternate config file (Default: /etc/openerp-server.conf).
CONFIGFILE="/etc/openerp-server.conf"

# pidfile
PIDFILE=/var/run/$NAME.pid

# Additional options that are passed to the Daemon.
DAEMON_OPTS="-c $CONFIGFILE"

[ -x $DAEMON ] || exit 0
[ -f $CONFIGFILE ] || exit 0

checkpid() {
    [ -f $PIDFILE ] || return 1
    pid=`cat $PIDFILE`
    [ -d /proc/$pid ] && return 0
    return 1
}

case "${1}" in
        start)
                echo -n "Starting ${DESC}: "

                start-stop-daemon --start --quiet --pidfile ${PIDFILE} 
                        --chuid ${USER} --background --make-pidfile 
                        --exec ${DAEMON} -- ${DAEMON_OPTS}

                echo "${NAME}."
                ;;

        stop)
                echo -n "Stopping ${DESC}: "

                start-stop-daemon --stop --quiet --pidfile ${PIDFILE} 
                        --oknodo

                echo "${NAME}."
                ;;

        restart|force-reload)
                echo -n "Restarting ${DESC}: "

                start-stop-daemon --stop --quiet --pidfile ${PIDFILE} 
                        --oknodo

                sleep 1

                start-stop-daemon --start --quiet --pidfile ${PIDFILE} 
                        --chuid ${USER} --background --make-pidfile 
                        --exec ${DAEMON} -- ${DAEMON_OPTS}

                echo "${NAME}."
                ;;

        *)
                N=/etc/init.d/${NAME}
                echo "Usage: ${NAME} {start|stop|restart|force-reload}" >&2
                exit 1
                ;;
esac

exit 0