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

From ArchWiki
Jump to: navigation, search
(Tips: most daemons create their own pid file: exception, not the rule; grammar; random bullet nesting)
(20 intermediate revisions by 8 users not shown)
Line 1: Line 1:
[[Category:Boot process (English)]]
+
[[Category:Boot process]]
[[Category:HOWTOs (English)]]
+
[[Category:Package development]]
 +
[[cs:Writing rc.d scripts]]
 +
[[es:Writing rc.d scripts]]
 +
[[zh-CN:Writing rc.d scripts]]
 
{{Article summary start}}
 
{{Article summary start}}
{{Article summary text|How to write rc.d (daemon) scripts.}}
+
{{Article summary text|Writing rc.d daemon scripts.}}
 
{{Article summary heading|Related}}
 
{{Article summary heading|Related}}
 +
{{Article summary wiki|Arch Boot Process}}
 
{{Article summary wiki|Daemon}}
 
{{Article summary wiki|Daemon}}
 
{{Article summary wiki|rc.conf}}
 
{{Article summary wiki|rc.conf}}
{{Article summary wiki|Arch_Boot_Process|Arch Boot Process}}
 
 
{{Article summary end}}
 
{{Article summary end}}
  
==Introduction==
+
[[Initscripts]] uses rc.d scripts to used to control the starting, stopping and restarting of [[Daemon|daemons]].
As part of Arch's 'BSD-style' init, rc.d scripts are used to control the starting,stopping and restarting of [[Daemon|daemons]]. This guide will help to create your own rc.d scripts.
+
  
==Basic scheme==
+
== Guideline ==
Most rc.d scripts follow the same structure but the details are typically specific to the daemon.
+
* 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.
 +
* 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.
  
===Daemon arguments===
+
== Available functions ==
Arguments to your daemon should be placed in {{Filename|/etc/conf.d/DAEMON_NAME}}
+
* There are some functions provided by {{ic|/etc/rc.d/functions}}:
 +
** {{Ic|stat_busy "''message''"}}: set status ''busy'' for printed message (e.g. <nowiki>Starting daemon  [BUSY]</nowiki>)
 +
** {{Ic|stat_done}}: set status ''done'' (e.g. <nowiki>Starting daemon  [DONE]</nowiki>)
 +
** {{Ic|stat_fail}}: set status ''failed'' (e.g. <nowiki>Starting daemon  [FAILED]</nowiki>)
 +
** {{Ic|get_pid ''program''}}: get PID of the program
 +
** {{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>)
 +
** {{Ic|<nowiki>[add|rm]_daemon</nowiki> ''program''}}: add/remove program to running daemons (stored in {{ic|/run/daemons/}})
  
===Prototype===
+
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}}.
<pre>
+
 
 +
== Example ==
 +
The following is an example for ''crond''. Look in {{ic|/etc/rc.d}} for greater variety.
 +
 
 +
The configuration file:
 +
{{hc|/etc/conf.d/crond|2=<nowiki>ARGS="-S -l info"</nowiki>}}
 +
 
 +
The actual script:
 +
{{hc|/etc/rc.d/crond|2=<nowiki>
 
#!/bin/bash
 
#!/bin/bash
  
Line 25: Line 44:
 
. /etc/rc.d/functions
 
. /etc/rc.d/functions
  
[ -r /etc/conf.d/$DAEMON.conf ] && . /etc/conf.d/$DAEMON.conf
+
DAEMON=crond
 +
ARGS=
  
DAEMON=DAEMON_NAME
+
[ -r /etc/conf.d/$DAEMON ] && . /etc/conf.d/$DAEMON
PID=$(pidof -o %PPID $DAEMON)
+
  
case "$1" in
+
PID=$(get_pid $DAEMON)
  start)
+
    stat_busy "Starting $DAEMON daemon"
+
    [ -z "$PID" ] && $DAEMON &>/dev/null
+
    if [ $? = 0 ]; then
+
      add_daemon $DAEMON
+
      stat_done
+
    else
+
      stat_fail
+
      exit 1
+
    fi
+
    ;;
+
  stop)
+
    stat_busy "Stopping $DAEMON daemon"
+
    [ -n "$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
+
    ;;
+
  status)
+
    stat_busy "Checking $DAEMON status"
+
    ck_status $DAEMON
+
    ;;
+
  *)
+
    echo "usage: $0 {start|stop|restart|status}"
+
esac
+
</pre>
+
 
+
==Example==
+
{{Tip|{{Filename|/etc/rc.d/}} and {{Filename|/etc/conf.d/}} contain many examples}}
+
 
+
A proper example for tftpd:
+
 
+
{{File|name=/etc/conf.d/tftpd|content=<nowiki>TFTPD_ARGS="-l -s /var/tftpboot -c"</nowiki>}}
+
 
+
{{File|name=/etc/rc.d/tftpd|content=<nowiki>
+
#!/bin/bash
+
. /etc/rc.conf
+
. /etc/rc.d/functions
+
 
+
TFTPD_ARGS=
+
[ -f /etc/conf.d/tftpd ] && . /etc/conf.d/tftpd
+
PID=`pidof -o %PPID /usr/sbin/in.tftpd`
+
  
 
case "$1" in
 
case "$1" in
 
  start)
 
  start)
   stat_busy "Starting TFTPD"
+
   stat_busy "Starting $DAEMON"
   [ -z "$PID" ] && /usr/sbin/in.tftpd ${TFTPD_ARGS}
+
   [ -z "$PID" ] && $DAEMON $ARGS &>/dev/null
   if [ $? -gt 0 ]; then
+
   if [ $? = 0 ]; then
 +
    add_daemon $DAEMON
 +
    stat_done
 +
  else
 
     stat_fail
 
     stat_fail
  else
+
     exit 1
     add_daemon in.tftpd
+
    stat_done
+
 
   fi
 
   fi
 
   ;;
 
   ;;
 
  stop)
 
  stop)
   stat_busy "Stopping TFTPD"
+
   stat_busy "Stopping $DAEMON"
   [ -n "$PID" ] && kill $PID &> /dev/null
+
   [ -n "$PID" ] && kill $PID &>/dev/null
   if [ $? -gt 0 ]; then
+
   if [ $? = 0 ]; then
 +
    rm_daemon $DAEMON
 +
    stat_done
 +
  else
 
     stat_fail
 
     stat_fail
  else
+
     exit 1
     rm_daemon in.tftpd
+
    stat_done
+
 
   fi
 
   fi
 
   ;;
 
   ;;
 
  restart)
 
  restart)
 
   $0 stop
 
   $0 stop
 +
  sleep 1
 
   $0 start
 
   $0 start
 
   ;;
 
   ;;
Line 111: Line 82:
 
   echo "usage: $0 {start|stop|restart}"   
 
   echo "usage: $0 {start|stop|restart}"   
 
esac
 
esac
exit 0
 
 
</nowiki>}}
 
</nowiki>}}
 
==Tips==
 
*Follow the same structure as other rc.d scripts
 
*Source {{Filename|/etc/rc.conf}}, {{Filename|/etc/rc.d/functions}}, and optionally {{Filename|/etc/conf.d/DAEMON_NAME}}
 
*Use functions in /etc/rc.d/functions
 
*Include at least start, stop and restart
 

Revision as of 06:00, 26 October 2012

Summary help replacing me
Writing rc.d daemon scripts.
Related
Arch Boot Process
Daemon
rc.conf

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