.Dd May 24, 2024
.Dt SERVICE 8
.Os
.Sh NAME
.Nm service
.Nd daemon maintenance
.Sh SYNOPSIS
.Nm service
.Op Fl lr
.Op Fl \-s Ns "=" Ns source-daemon
.Op Fl \-exit-code
.Op Fl \-no-await
.Op Fl \-no-optional
.Op Fl \-raw
.Op Fl \-source Ns "=" Ns source-daemon
.Ar daemon
.Oo
.Sy dependents
|
.Sy disable
|
.Sy edges
|
.Sy enable
|
.Sy exit-code
|
.Sy kill
|
.Sy pid
|
.Sy reconfigure
|
.Sy reload
|
.Sy requirements
|
.Sy restart
|
.Sy signal
|
.Sy start
|
.Sy state
|
.Sy status
|
.Sy stop
|
.Sy terminate
.Oc
.Sh DESCRIPTION
.Nm
performs maintenance of daemons run by
.Xr init 8
as configured in
.Xr init 5 .
The daemons are serviced by connecting to the
.Nm init
process and writing the requested command to the
.Pa /var/run/init
filesytem socket.
.Pp
The options are as follows:
.Bl -tag -width "12345678"
.It Fl s , Fl \-source-daemon Ns "=" Ns Ar source-daemon
When modifying a dependency using the
.Sy enable , disable , start
and
.Sy stop
commands, use the
.Ar source-daemon
as the source daemon in the dependency on the target
.Ar daemon .
The default the
.Sy local
daemon which is the parent of the locally configured daemons.
.It Fl \-exit-code
Set the
.Sy exit-code
flag on the dependency created in the
.Sy enable
and
.Sy start
commands.
.It Fl \-no-await
Set the
.Sy no-await
flag on the dependency created in the
.Sy enable
and
.Sy start
commands.
.It Fl \-no-optional
Unset the
.Sy optional
flag on the dependency created in the
.Sy enable
and
.Sy start
commands.
The default is to set the
.Sy optional
flag, which is the opposite of the
.Xr init 5
.Sy require
declaration where dependencies are mandatory by default.
.It Fl l , \-list
Write a table containing the status of every loaded daemon in the format of the
.Sy status
command.
.It Fl r , \-raw
Write the command and additional operands as a raw message without verification
on the
.Nm init
socket
and output the raw reply sent from
.Nm init.
.El
.Pp
The commands are as follows:
.Bl -tag -width "requirements"
.It Sy dependents
Write the incoming dependencies on the
.Ar daemon
in the format of the
.Sy edges
command, which explains why a daemon is running.
.It Sy disable
Permanently disable the
.Ar daemon
by removing the dependency on it from the configuration of the
.Ar source-daemon
(the
.Sy local
daemon by default, see
.Xr init 5 )
and then stopping it using the
.Sy stop
command.
The daemon will continue to run if any other daemon depends on it, which can
be diagnosed using the
.Sy dependents
command.
.It Sy edges
Write the incoming dependencies on the
.Ar daemon
and its outgoing dependencies in the format of the
.Sy require
declaration in
.Xr init 5
with an extra
.Ar source
operand:
.Pp
.Sy require
.Ar source
.Ar target
[exit-code]
[no-await]
[optional]
.It Sy enable
Permanently enable the
.Ar daemon
by adding it to the configuration of the
.Ar source-daemon
(the
.Sy local
daemon by default, see
.Xr init 5 )
with the dependency flags per
.Fl \-exit-code ,
.Fl \-no-await ,
and
.Fl \-no-optional
and starting it by sending the
.Sy start
command.
The daemon only starts if the
.Ar source-daemon
is running.
.It Sy exit-code
Write the exit code of the
.Ar daemon ,
or the empty string if it has not exited.
.It Sy kill
Kill the
.Ar daemon
by sending the
.Sy SIGKILL
signal as a last resort that may cause data loss.
.It Sy pid
Write the process id of the
.Ar daemon
if it is running, or the empty output if it
does not have a process.
Process ids can be recycled and are subject to inherent race conditions.
Prefer to use the other commands in
.Nm
that addresses the daemon by its symbolic name as
.Xr init 8
will ensure the command operates on the correct process.
.It Sy reconfigure
Reread the
.Xr init 5
configuration for the
.Ar daemon
and apply it after restarting the daemon.
.It Sy reload
Request the
.Ar daemon
gracefully reload its own configuration sending
the reload signal (usually
.Sy SIGHUP )
without restarting the daemon and without reloading the
.Xr init 5
configuration.
.It Sy requirements
Write the outgoing dependencies from the
.Ar daemon
in the format of the
.Sy edges
command, which explains what daemons the daemon needs.
.It Sy restart
Restart the
.Ar daemon
by terminating it and starting it up again afterwards.
.It Sy signal Ar signal
Send the
.Ar signal
in the symbolic signal name format (e.g.
.Sy SIGUSR1 )
to the
.Ar daemon .
.It Sy start
Start the
.Ar daemon
by asking
.Xr init 8
to add a runtime dependency from the
.Ar source-daemon
(the
.Sy local
daemon by default, see
.Xr init 5 )
to the daemon with the dependency flags per
.Fl \-exit-code ,
.Fl \-no-await ,
and
.Fl \-no-optional
and starting it by sending the
.Sy start
command.
The daemon only starts if the
.Ar source-daemon
is running.
.It Sy state
Write which the state the
.Ar daemon
is in.
.It Sy status
Write the status of the
.Ar daemon
as a single table row in the format:
.Pp
.Ar name
.Ar state
.Li pid Ns "=" Ns Ar pid
.Li exit Ns "=" Ns Ar exit-code
.Pp
The
.Ar state
is one of
.Sy terminated ,
.Sy scheduled ,
.Sy waiting ,
.Sy satisfied ,
.Sy starting ,
.Sy running ,
.Sy terminating ,
.Sy finishing ,
.Sy finished ,
or
.Sy failed .
The
.Ar pid
is the process id if any, or
.Li 0
otherwise.
The
.Ar exit-code
is the exit code of the daemon if it has exited, or the name of a signal that
killed it, or
.Li n/a
if the daemon has not exited.
.It Sy stop
Stop the
.Ar daemon
by asking
.Xr init 8
to remove the dependency from the
.Ar source-daemon
(the
.Sy local
daemon by default, see
.Xr init 5 )
on the daemon.
The daemon will continue to run as long if other daemon depends on it, which can
be diagnosed using the
.Sy dependents
command.
.It Sy terminate
Terminate the
.Ar daemon
gracefully by sending the
.Sy SIGTERM
signal and
.Sy SIGKILL
after a timeout.
Prefer the
.Sy stop
command if possible as the
.Sy terminate
command bypasses the reference count and may cause data loss if other daemons
malfunction when the daemon is unexpectedly terminated.
.El
.Sh ENVIRONMENT
.Bl -tag -width "INIT_SOCKET"
.It Ev INIT_SOCKET
.Xr init 8 Ns 's
filesystem socket for communication,
.Pa /var/run/init
by default.
.El
.Sh FILES
.Bl -tag -width "/etc/init/local" -compact
.It Pa /etc/init/
Daemon configuration for the local system (first in search path) (see
.Xr init 5 )
.It Pa /etc/init/local
Configuration for the
.Sy local
daemon (see
.Xr init 5 )
.El
.Sh EXIT STATUS
.Nm
will exit 0 on success and non-zero otherwise.
.Sh EXAMPLES
Permanently enable the sshd daemon:
.Bd -literal
$ service sshd enable
.Ed
.Pp
Permanently disable the ntpd daemon:
.Bd -literal
$ service ntpd disable
.Ed
.Pp
Temporarily start the nginx daemon without changing
.Pa /etc/init/local :
.Bd -literal
$ service nginx start
.Ed
.Pp
Temporarily disable the sshd daemon without changing
.Pa /etc/init/local :
.Bd -literal
$ service sshd stop
.Ed
.Pp
Temporarily stop the ntpd daemon and diagnose why it kept running due to the
.Sy time
daemon depending on it:
.Bd -literal
$ service ntpd stop
$ service ntpd state
running
$ service ntpd dependents
require time ntpd exit-code
$ service --source-daemon=time ntpd stop
$ service ntpd state
finished
.Ed
.Sh SEE ALSO
.Xr kill 1 ,
.Xr init 5 ,
.Xr halt 8 ,
.Xr init 8 ,
.Xr poweroff 8 ,
.Xr reboot 8