Difference between revisions of "Initscripts/Writing rc.d scripts"

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If a daemon accepts arguments, the script must have its equivalent in /etc/conf.d.
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[[Category:Boot process]]
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[[Category:Package development]]
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[[cs:Writing rc.d scripts]]
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[[es:Writing rc.d scripts]]
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[[zh-CN:Writing rc.d scripts]]
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{{Article summary start}}
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{{Article summary text|Writing rc.d daemon scripts.}}
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{{Article summary heading|Related}}
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{{Article summary wiki|Arch Boot Process}}
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{{Article summary wiki|Daemon}}
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{{Article summary wiki|rc.conf}}
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{{Article summary end}}
  
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[[Initscripts]] uses rc.d scripts to used to control the starting, stopping and restarting of [[Daemon|daemons]].
  
A proper example for tftpd:
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== Guideline ==
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* Source {{ic|/etc/rc.conf}}, {{ic|/etc/rc.d/functions}}, and optionally {{ic|/etc/conf.d/DAEMON_NAME}}.
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* Arguments and other daemon options should be placed in {{ic|/etc/conf.d/DAEMON_NAME}}. This is done to separate configuration from logic and to keep a consistent style among daemon scripts.
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* Use functions in {{ic|/etc/rc.d/functions}} instead of duplicating their functionality.
 +
* Include at least start, stop and restart as arguments to the script.
  
/etc/conf.d/tftpd:
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== Available functions ==
TFTPD_ARGS="-l -s /var/tftpboot -c"
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* There are some functions provided by {{ic|/etc/rc.d/functions}}:
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** {{Ic|stat_busy "''message''"}}: set status ''busy'' for printed message (e.g. <nowiki>Starting daemon  [BUSY]</nowiki>)
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** {{Ic|stat_done}}: set status ''done'' (e.g. <nowiki>Starting daemon  [DONE]</nowiki>)
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** {{Ic|stat_fail}}: set status ''failed'' (e.g. <nowiki>Starting daemon  [FAILED]</nowiki>)
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** {{Ic|get_pid ''program''}}: get PID of the program
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** {{Ic|ck_pidfile ''PID-file'' ''program''}}: check whether PID-file is still valid for the program (e.g. <nowiki>ck_pidfile /var/run/daemon.pid daemon || rm -f /var/run/daemon.pid</nowiki>)
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** {{Ic|<nowiki>[add|rm]_daemon</nowiki> ''program''}}: add/remove program to running daemons (stored in {{ic|/run/daemons/}})
  
/etc/rc.d/tftpd
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Full list of functions is much longer and most possibilities (like way to control whether or not non-root users can launch daemon) are still undocumented and can be learned only from {{ic|/etc/rc.d/functions}} source. See also {{Ic|man rc.d}}.
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#!/bin/bash
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. /etc/rc.conf
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== Example ==
. /etc/rc.d/functions
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The following is an example for ''crond''. Look in {{ic|/etc/rc.d}} for greater variety.
  
TFTPD_ARGS=
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The configuration file:
[ -f /etc/conf.d/tftpd ] && . /etc/conf.d/tftpd
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{{hc|/etc/conf.d/crond|2=<nowiki>ARGS="-S -l info"</nowiki>}}
  
PID=`pidof -o %PPID /usr/sbin/in.tftpd`
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The actual script:
case "$1" in
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{{hc|/etc/rc.d/crond|2=<nowiki>
  start)
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#!/bin/bash
    stat_busy "Starting TFTPD"
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    [ -z "$PID" ] && /usr/sbin/in.tftpd ${TFTPD_ARGS}
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. /etc/rc.conf
    if [ $? -gt 0 ]; then
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. /etc/rc.d/functions
      stat_fail
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    else
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DAEMON=crond
      add_daemon in.tftpd
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ARGS=
      stat_done
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    fi
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[ -r /etc/conf.d/$DAEMON ] && . /etc/conf.d/$DAEMON
    ;;
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  stop)
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PID=$(get_pid $DAEMON)
    stat_busy "Stopping TFTPD"
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    [ ! -z "$PID" ] && kill $PID &> /dev/null
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case "$1" in
    if [ $? -gt 0 ]; then
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start)
      stat_fail
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  stat_busy "Starting $DAEMON"
    else
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  [ -z "$PID" ] && $DAEMON $ARGS &>/dev/null
      rm_daemon in.tftpd
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  if [ $? = 0 ]; then
      stat_done
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    add_daemon $DAEMON
    fi
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    stat_done
    ;;
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  else
  restart)
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    stat_fail
    $0 stop
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    exit 1
    $0 start
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  fi
    ;;
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  ;;
  *)
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stop)
    echo "usage: $0 {start|stop|restart}"   
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  stat_busy "Stopping $DAEMON"
esac
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  [ -n "$PID" ] && kill $PID &>/dev/null
exit 0
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  if [ $? = 0 ]; then
 +
    rm_daemon $DAEMON
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    stat_done
 +
  else
 +
    stat_fail
 +
    exit 1
 +
  fi
 +
  ;;
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restart)
 +
  $0 stop
 +
  sleep 1
 +
  $0 start
 +
  ;;
 +
*)
 +
  echo "usage: $0 {start|stop|restart}"   
 +
esac
 +
</nowiki>}}

Revision as of 06:00, 26 October 2012

Template:Article summary start Template:Article summary text Template:Article summary heading Template:Article summary wiki Template:Article summary wiki Template:Article summary wiki Template:Article summary end

Initscripts uses rc.d scripts to used to control the starting, stopping and restarting of daemons.

Guideline

  • Source /etc/rc.conf, /etc/rc.d/functions, and optionally /etc/conf.d/DAEMON_NAME.
  • Arguments and other daemon options should be placed in /etc/conf.d/DAEMON_NAME. This is done to separate configuration from logic and to keep a consistent style among daemon scripts.
  • Use functions in /etc/rc.d/functions instead of duplicating their functionality.
  • Include at least start, stop and restart as arguments to the script.

Available functions

  • There are some functions provided by /etc/rc.d/functions:
    • stat_busy "message": set status busy for printed message (e.g. Starting daemon [BUSY])
    • stat_done: set status done (e.g. Starting daemon [DONE])
    • stat_fail: set status failed (e.g. Starting daemon [FAILED])
    • get_pid program: get PID of the program
    • ck_pidfile PID-file program: check whether PID-file is still valid for the program (e.g. ck_pidfile /var/run/daemon.pid daemon || rm -f /var/run/daemon.pid)
    • [add|rm]_daemon program: add/remove program to running daemons (stored in /run/daemons/)

Full list of functions is much longer and most possibilities (like way to control whether or not non-root users can launch daemon) are still undocumented and can be learned only from /etc/rc.d/functions source. See also man rc.d.

Example

The following is an example for crond. Look in /etc/rc.d for greater variety.

The configuration file:

/etc/conf.d/crond
ARGS="-S -l info"

The actual script:

/etc/rc.d/crond
#!/bin/bash

. /etc/rc.conf
. /etc/rc.d/functions

DAEMON=crond
ARGS=

[ -r /etc/conf.d/$DAEMON ] && . /etc/conf.d/$DAEMON

PID=$(get_pid $DAEMON)

case "$1" in
 start)
   stat_busy "Starting $DAEMON"
   [ -z "$PID" ] && $DAEMON $ARGS &>/dev/null
   if [ $? = 0 ]; then
     add_daemon $DAEMON
     stat_done
   else
     stat_fail
     exit 1
   fi
   ;;
 stop)
   stat_busy "Stopping $DAEMON"
   [ -n "$PID" ] && kill $PID &>/dev/null
   if [ $? = 0 ]; then
     rm_daemon $DAEMON
     stat_done
   else
     stat_fail
     exit 1
   fi
   ;;
 restart)
   $0 stop
   sleep 1
   $0 start
   ;;
 *)
   echo "usage: $0 {start|stop|restart}"  
esac