init-d-script

INIT-D-SCRIPT(5)            BSD File Formats Manual           INIT-D-SCRIPT(5)

NAME
     init-d-script -- interpreter for short and simple init.d scripts

DESCRIPTION
     Generic init.d script framework to reduce the redundant code in
     /etc/init.d/.  The goal is to create an init.d script that is Debian and
     LSB compliant.  When the Debian policy conflicts with the LSB, the Debian
     policy takes precedence.

     This is a simple example on how init-d-script can be used to start and
     stop a daemon with PID file support:

           #!/usr/bin/env /lib/init/init-d-script
           ### BEGIN INIT INFO
           # Provides:          atd
           # Required-Start:    $syslog $time $remote_fs
           # Required-Stop:     $syslog $time $remote_fs
           # Default-Start:     2 3 4 5
           # Default-Stop:      0 1 6
           # Short-Description: run at jobs
           # Description:       Debian init script to start the daemon
           #                    running at jobs.
           ### END INIT INFO
           DAEMON=/usr/sbin/atd

     The following variables affect behaviour of an init script:

     DAEMON       Path to daemon being started.  If the init script is not
                  supposed to start any kind of daemon, the functions
                  do_start_override(), do_stop_override() and
                  do_status_override() should be defined instead.

     DAEMON_ARGS  Additional arguments, passed to daemon during start.

     NAME         Additional environment variables are sources from
                  /etc/default/${NAME}.  If unset, this variable defaults to
                  the basename of the "DAEMON" value.

     COMMAND_NAME
                  If this variable is set, it is used as argument to the
                  --name option of start-stop-daemon(8).  It may be useful if
                  the value of the NAME variable is too long.

     PIDFILE      Path to file where the process identifier of the started
                  daemon will be stored during start.  If the value is verba-
                  tim "none", the process identifier will not be stored in any
                  file.  If this variable is not set, it gets a sensible de-
                  fault value, so it is rarely necessary to set this variable
                  explicitly.

     Additionally, it is possible to change the behaviour of the resulting
     shell script by overriding some of the internal functions.  To do so, de-
     fine function with an _override suffix.  So, for example, to override the
     do_status() function, one should define a do_status_override() function.
     The exception to this rule is the do_reload() function, whose override
     should be defined as-is, without the above-mentioned suffix.

     Here is a control flow chart that explains what functions are called and
     when:

           /etc/init.d/script start
             do_start
               do_start_prepare # no-op
               do_start_cmd     # start-stop-daemon is called here
               do_start_cleanup # no-op

           /etc/init.d/script stop
             do_stop
               do_stop_prepare # no-op
               do_stop_cmd     # start-stop-daemon is called here
               do_stop_cleanup # no-op

           /etc/init.d/script status
             do_status

           /etc/init.d/script reload
             do_reload
               do_usage
               exit 3

           /etc/init.d/script force-reload
             do_force_reload
               do_reload   # if overridden
               do_restart
                 do_restart_prepare
                 do_stop_cmd
                 do_start_cmd
                 do_restart_cleanup

           /etc/init.d/script restart
             do_force_restart
           /etc/init.d/script try-restart
             if do_status; then
               do_restart
                 do_restart_prepare
                 do_stop_cmd  # start-stop-daemon is called here
                 do_start_cmd # start-stop-daemon is called here
                 do_restart_cleanup

           /etc/init.d/script <arg>
             do_unknown <arg>
               exit 3

           /etc/init.d/script
             do_usage

     As can be seen, by default, the script does not support the reload ac-
     tion; it should be implemented by the script writer by defining a
     do_reload() function.

     If the daemon performs reload action upon receiving a SIGUSR1 signal, a
     generic implementation can be used with the following code:

           alias do_reload=do_reload_sigusr1

SEE ALSO
     inittab(8), service(8), update-rc.d(8).

AUTHORS
     Petter Reinholdtsen <pere@debian.org>

Debian                          August 5, 2019                          Debian