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

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[[Category:Boot process (English)]]
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[[Category:Boot process]]
{{i18n|Writing rc.d scripts}}
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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]]
 
{{Article summary start}}
 
{{Article summary start}}
 
{{Article summary text|Writing rc.d daemon scripts.}}
 
{{Article summary text|Writing rc.d daemon scripts.}}
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{{Article summary end}}
 
{{Article summary end}}
  
As part of Arch's 'BSD-style' init, rc.d scripts are used to control the starting, stopping and restarting of [[Daemon|daemons]].
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[[Initscripts]] uses rc.d scripts to used to control the starting, stopping and restarting of [[Daemon|daemons]].
  
==Guideline==
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== Guideline ==
*Source {{ic|/etc/rc.conf}}, {{ic|/etc/rc.d/functions}}, and optionally {{ic|/etc/conf.d/DAEMON_NAME}}.
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* Source {{ic|/etc/rc.conf}}, {{ic|/etc/rc.d/functions}}, and optionally {{ic|/etc/conf.d/DAEMON_NAME}}.
*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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* 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.
*Use functions in {{ic|/etc/rc.d/functions}} instead of duplicating their functionality.
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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.
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* Include at least start, stop and restart as arguments to the script.
*There are some functions provided by {{ic|/etc/rc.d/functions}}:
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**stat_busy "<message>": set status ''busy'' for printed message (e.g. <nowiki>Starting daemon  [BUSY]</nowiki>)
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**stat_done: set status ''done'' (e.g. <nowiki>Starting daemon  [DONE]</nowiki>)
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**stat_fail: set status ''failed'' (e.g. <nowiki>Starting daemon  [FAILED]</nowiki>)
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**get_pid <program>: get PID of the program
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**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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**[add|rm]_daemon <program>: add/remove program to running daemons (stored in {{ic|/run/daemons/}})
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==Example==
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== Available functions ==
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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/}})
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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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== Example ==
 
The following is an example for ''crond''. Look in {{ic|/etc/rc.d}} for greater variety.
 
The following is an example for ''crond''. Look in {{ic|/etc/rc.d}} for greater variety.
  

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