init-d-script
INIT-D-SCRIPT(5) File Formats Manual INIT-D-SCRIPT(5)
NAME
init-d-script — interpreter for short and simple init.d scriptsDESCRIPTION
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 con‐
flicts 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 $remote_fs
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: run at jobs
# Description: Debian init script to start the daemon
# running at jobs.
### END INIT INFO
DAEMON=/usr/sbin/atd
The following variables affect behaviour of an init script:
DAEMON Path to daemon being started. If the init script is not supposed to start any kind of daemon, it should be set to “none” and the functions do_start_override(),
do_stop_override() and do_status_override() should be defined instead.
DAEMON_ARGS Additional arguments, passed to daemon during start.
DESC Full name or short description of the daemon, printed on screen. If unset, this variable defaults to the “NAME” value.
NAME Additional environment variables are sourced from /etc/default/${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 vari‐
able defaults 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 verbatim “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 variable explicitly.
SETPRIV_ARGS If this directive is set and setpriv(1) is available, the invocation of start-stop-daemon(8) is wrapped in a call to setpriv(1) with the specified arguments. Note that
the --chuid argument to start-stop-daemon(8) requires CAP_SETUID and CAP_SETGID in the bounding capabilities set.
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
variable should be set to “1” or “HUP”.
The variables RELOAD_ARGS, START_ARGS and STOP_ARGS are additional arguments, passed to start-stop-daemon(8) during reload, start and stop actions, 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, define 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 action; 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), setpriv(1), update-rc.d(8).AUTHORS
Petter Reinholdtsen <pere@debian.org>Debian September 3, 2024 INIT-D-SCRIPT(5)