openrc/man/start-stop-daemon.8

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.Dd December 14, 2009
.Dt START-STOP-DAEMON 8 SMM
.Os OpenRC
.Sh NAME
.Nm start-stop-daemon
.Nd ensures that daemons start and stop
.Sh SYNOPSIS
.Nm
.Fl S , -start
.Ar daemon
.Op Fl -
.Op Ar arguments
.Nm
.Fl K , -stop
.Ar daemon
.Nm
.Fl s , -signal
.Ar signal
.Ar daemon
.Sh DESCRIPTION
.Nm
provides a consistent method of starting, stopping and signaling daemons.
If neither
.Fl K , -stop
nor
.Fl s , -signal
are provided, then we assume we are starting the daemon.
If a daemon cannot background by itself, nor create a pidfile,
.Nm
can do it for the daemon in a secure fashion.
.Pp
If
.Nm
is used in an OpenRC service, then OpenRC can in turn check to see if the
daemon is still running. If not, then the service is marked as crashed.
.Pp
Here are the options to specify the daemon and how it should start or stop:
.Bl -tag -width indent
.It Fl x , -exec Ar daemon
The
.Ar daemon
we start or stop.
If this option is not specified, then the first non option argument
is used.
.It Fl p , -pidfile Ar pidfile
When starting, we expect the daemon to create a valid
.Ar pidfile
within a reasonable amount of time. When stopping we only stop the first pid
listed in the
.Ar pidfile .
.It Fl n , -name Ar name
Match the process
.Ar name
instead of a pidfile or executable.
.It Fl i , -interpreted
When matching process name, we should ensure that the correct interpreter
is also matched.
So if the daemon foo starts off like so
.D1 #!/usr/bin/perl -w
then
.Nm
matches the process
.D1 /usr/bin/perl -w foo
If an interpreted daemon changes its process name then this won't work.
.It Fl u , -user Ar user Ns Op : Ns Ar group
Start the daemon as the
.Ar user
and update $HOME accordingly or stop daemons
owned by the user. You can optionally append a
.Ar group
name here also.
.It Fl t , -test
Print the action(s) that would be taken, but don't actually do anything.
The return value is set as if the command was taken and worked.
.It Fl v , -verbose
Print the action(s) that are taken just before doing them.
.It Fl P , -progress
Echo a . to the console for each second elapsed whilst waiting.
.El
.Pp
These options are only used for starting daemons:
.Bl -tag -width indent
.It Fl a , -startas Ar name
Change the process name of the daemon to
.Ar name .
This just changes the first argument passed to the daemon.
.It Fl b , -background
Force the daemon into the background. Some daemons don't create pidfiles, so a
good trick is to get the daemon to run in the foreground, and use the this
option along with
.Fl m , -make-pidfile
to create a working pidfile.
.It Fl d , -chdir Ar path
chdir to this directory before starting the daemon.
.It Fl r , -chroot Ar path
chroot to this directory before starting the daemon. All other paths, such
as the path to the daemon, chdir and pidfile, should be relative to the chroot.
.It Fl c , -chuid Ar user
Same as the
.Fl u , -user
option.
.It Fl e , -env Ar VAR=VALUE
Set the environment variable VAR to VALUE.
.It Fl g , -group Ar group
Start the daemon as in the group.
.It Fl k , -umask Ar mode
Set the umask of the daemon.
.It Fl m , -make-pidfile
Saves the pid of the daemon in the file specified by the
.Fl p , -pidfile
option. Only useful when used with daemons that run in the foreground and
forced into the background with the
.Fl b , -background
option.
.It Fl I , -ionice Ar class Ns Op : Ns Ar data
Modifies the IO scheduling priority of the daemon.
Class can be 0 for none, 1 for real time, 2 for best effort and 3 for idle.
Data can be from 0 to 7 inclusive.
.It Fl N , -nicelevel Ar level
Modifies the scheduling priority of the daemon.
.It Fl -oom-score-adj Ar adj
Modifies the OOM score adjustment of the daemon.
.It Fl 1 , -stdout Ar logfile
Redirect the standard output of the process to logfile when started with
.Fl background .
The logfile Must be an absolute pathname, but relative to the path
optionally given with
.Fl r , -chroot .
The logfile can also be a named pipe.
.It Fl 2 , -stderr Ar logfile
Redirect the standard error of the process to logfile when started with
.Fl background .
The logfile must be an absolute pathname, but relative to the path
optionally given with
.Fl r , -chroot .
The logfile can also be a named pipe.
.It Fl 3 , -stdout-logger Ar cmd
Run cmd as a child process redirecting the standard output to the
standard input of cmd when started with
.Fl background .
Cmd must be an absolute pathname, but relative to the path optionally given with
.Fl r , -chroot .
This process must be prepared to accept input on stdin and be able to
log it or send it to another location.
.It Fl 4 , -stderr-logger Ar cmd
Run cmd as a child process and 
Redirect the standard error of the process to the standard input of cmd
when started with
.Fl background .
Cmd must be an absolute pathname, but relative to the path optionally given with
.Fl r , -chroot .
This process must be prepared to accept input on stdin and be able to
log it or send it to another location.
.It Fl -capabilities Ar cap-list
Start the daemon with the listed inheritable, ambient and bounding capabilities.
The format is the same as in cap_iab(3).
.It Fl w , -wait Ar milliseconds
Wait
.Ar milliseconds
after starting and check that daemon is still running.
Useful for daemons that check configuration after forking or stopping race
conditions where the pidfile is written out after forking.
.It Fl 2 , -stderr Ar logfile
The same thing as
.Fl 1 , -stdout
but with the standard error output.
.El
.Pp
These options are only used for stopping daemons:
.Bl -tag -width indent
.It Fl R , -retry Ar timeout | Ar signal Ns / Ns Ar timeout
The retry specification can be either a timeout in seconds or multiple
signal/timeout pairs (like SIGTERM/5).
If this option is not given, the default is SIGTERM/5.
.El
.Sh ENVIRONMENT
.Va SSD_IONICELEVEL
can also set the IO scheduling priority of the daemon, but the command line
option takes precedence.
.Pp
.Va SSD_NICELEVEL
can also set the scheduling priority of the daemon, but the command line
option takes precedence.
.Pp
.Va SSD_OOM_SCORE_ADJ
can also set the OOM score adjustment of the daemon, but the command line
option takes precedence.
.Pp
.Va SSD_STARTWAIT
As the
.Fl w , -wait option above.
.Pa /etc/rc.conf
.Nm
waits for to check the daemon is still running.
.Sh NOTE
.Nm
uses
.Xr getopt 3
to parse its options, which allows it to accept the `--' option which will
cause it to stop processing options at that point. Any subsequent arguments
are passed as arguments to the daemon to start and used when finding a daemon
to stop or signal.
.Sh SEE ALSO
.Xr chdir 2 ,
.Xr chroot 2 ,
.Xr getopt 3 ,
.Xr nice 2 ,
.Xr rc_find_pids 3
.Sh BUGS
.Nm
cannot stop an interpreted daemon that no longer exists without a pidfile.
.Sh HISTORY
.Nm
first appeared in Debian.
.Pp
This is a complete re-implementation with the process finding code in the
OpenRC library (librc, -lrc) so other programs can make use of it.
.Sh AUTHORS
.An Roy Marples <roy@marples.name>