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:

           #!/bin/sh /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, it should be set to
                    "none" and the functions do_start_override(),
                    do_stop_override() and do_status_override() should be de-
                    fined instead.

     DAEMON_ARGS    Additional arguments, passed to daemon during start.

     DESC           Full name or short description of the daemon, printed on
                    screen.  If unset, this variable defaults to the "NAME"
                    value.

     NAME           Additional environment variables are sourced 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 longer than the
                    command name length supported by the running kernel.  If
                    the value is verbatim "none", the command name will not be
                    used to match the processes.  If unset, this variable de-
                    faults to the "NAME" value.

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

     RELOAD_SIGNAL  Signal number or name (without the SIG prefix) that will
                    be sent to the process on reload.  If the daemon performs
                    reload action upon receiving a SIGHUP signal, this vari-
                    able should be set to "1" or "HUP".

     The variables RELOAD_ARGS, START_ARGS and STOP_ARGS are additional argu-
     ments, passed to start-stop-daemon(8) during reload, start and stop ac-
     tions, to override the default options.

     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 do_reload() is not defined but do_reload_cmd() is, the latter will be
     called on reload, after do_reload_prepare() and before
     do_reload_cleanup().

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

AUTHORS
     Petter Reinholdtsen <pere@debian.org>

Debian                          August 5, 2019                          Debian