1 .\" dpkg manual page - start-stop-daemon(8)
2 .\"
3 .\" Copyright © 1999 Klee Dienes <klee@mit.edu>
4 .\" Copyright © 1999 Ben Collins <bcollins@debian.org>
5 .\" Copyright © 2000-2001 Wichert Akkerman <wakkerma@debian.org>
6 .\" Copyright © 2002-2003 Adam Heath <doogie@debian.org>
7 .\" Copyright © 2004 Scott James Remnant <keybuk@debian.org>
8 .\" Copyright © 2008-2015 Guillem Jover <guillem@debian.org>
9 .\"
10 .\" This is free software; you can redistribute it and/or modify
11 .\" it under the terms of the GNU General Public License as published by
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15 .\" This is distributed in the hope that it will be useful,
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18 .\" GNU General Public License for more details.
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22 .
23 .TH start\-stop\-daemon 8 "2017-07-04" "Debian Project" "dpkg suite"
24 .nh
25 .SH NAME
26 start\-stop\-daemon \- start and stop system daemon programs
27 .
28 .SH SYNOPSIS
29 .B start\-stop\-daemon
30 .RI [ option "...] " command
31 .
32 .SH DESCRIPTION
33 .B start\-stop\-daemon
34 is used to control the creation and termination of system-level processes.
35 Using one of the matching options, \fBstart\-stop\-daemon\fP
36 can be configured to find existing instances of a running process.
37 .PP
38 Note: unless
39 .B \-\-pid
40 or
41 .B \-\-pidfile
42 are specified,
43 .B start\-stop\-daemon
44 behaves similar to
45 .BR killall (1).
46 .B start\-stop\-daemon
47 will scan the process table looking for any processes which
48 match the process name, parent pid, uid, and/or gid (if specified). Any
49 matching process will prevent
50 .BR \-\-start
51 from starting the daemon. All matching processes will be sent the TERM
52 signal (or the one specified via \fB\-\-signal\fP or \fB\-\-retry\fP) if
53 .BR \-\-stop
54 is specified. For daemons which have long-lived children
55 which need to live through a
56 .BR \-\-stop ,
57 you must specify a pidfile.
58 .
59 .SH COMMANDS
60 .TP
61 .BR \-S ", " \-\-start " [" \-\- "] \fIarguments\fP"
62 Check for the existence of a specified process.
63 If such a process exists,
64 .B start\-stop\-daemon
65 does nothing, and exits with error status 1 (0 if
66 .BR \-\-oknodo
67 is specified).
68 If such a process does not exist, it starts an
69 instance, using either the executable specified by
70 .B \-\-exec
71 or, if specified, by
72 .BR \-\-startas .
73 Any arguments given after
74 .BR \-\-
75 on the command line are passed unmodified to the program being
76 started.
77 .TP
78 .BR \-K ", " \-\-stop
79 Checks for the existence of a specified process.
80 If such a process exists,
81 .B start\-stop\-daemon
82 sends it the signal specified by
83 .BR \-\-signal ,
84 and exits with error status 0.
85 If such a process does not exist,
86 .B start\-stop\-daemon
87 exits with error status 1
88 (0 if
89 .BR \-\-oknodo
90 is specified). If
91 .B \-\-retry
92 is specified, then
93 .B start\-stop\-daemon
94 will check that the process(es) have terminated.
95 .TP
96 .BR \-T ", " \-\-status
97 Check for the existence of a specified process, and returns an exit status
98 code, according to the LSB Init Script Actions (since version 1.16.1).
99 .TP
100 .BR \-H ", " \-\-help
101 Show usage information and exit.
102 .TP
103 .BR \-V ", " \-\-version
104 Show the program version and exit.
105 .
106 .SH OPTIONS
107 .SS Matching options
108 .TP
109 .BR \-\-pid " \fIpid\fP"
110 Check for a process with the specified \fIpid\fP (since version 1.17.6).
111 The \fIpid\fP must be a number greater than 0.
112 .TP
113 .BR \-\-ppid " \fIppid\fP"
114 Check for a process with the specified parent pid \fIppid\fP
115 (since version 1.17.7).
116 The \fIppid\fP must be a number greater than 0.
117 .TP
118 .BR \-p ", " \-\-pidfile " \fIpid-file\fP"
119 Check whether a process has created the file \fIpid-file\fP. Note: using this
120 matching option alone might cause unintended processes to be acted on, if the
121 old process terminated without being able to remove the \fIpid-file\fP.
122 .TP
123 .BR \-x ", " \-\-exec " \fIexecutable\fP"
124 Check for processes that are instances of this \fIexecutable\fP. The
125 \fIexecutable\fP argument should be an absolute pathname. Note: this might
126 not work as intended with interpreted scripts, as the executable will point
127 to the interpreter. Take into account processes running from inside a chroot
128 will also be matched, so other match restrictions might be needed.
129 .TP
130 .BR \-n ", " \-\-name " \fIprocess-name\fP"
131 Check for processes with the name \fIprocess-name\fP. The \fIprocess-name\fP
132 is usually the process filename, but it could have been changed by the
133 process itself. Note: on most systems this information is retrieved from
134 the process comm name from the kernel, which tends to have a relatively
135 short length limit (assuming more than 15 characters is non-portable).
136 .TP
137 .BR \-u ", " \-\-user " \fIusername\fP|\fIuid\fP
138 Check for processes owned by the user specified by \fIusername\fP or
139 \fIuid\fP. Note: using this matching option alone will cause all processes
140 matching the user to be acted on.
141 .
142 .SS Generic options
143 .TP
144 .BR \-g ", " \-\-group " \fIgroup\fP|\fIgid\fP"
145 Change to \fIgroup\fP or \fIgid\fP when starting the process.
146 .TP
147 .BR \-s ", " \-\-signal " \fIsignal\fP"
148 With
149 .BR \-\-stop ,
150 specifies the signal to send to processes being stopped (default TERM).
151 .TP
152 .BR \-R ", " \-\-retry " \fItimeout\fP|\fIschedule\fP"
153 With
154 .BR \-\-stop ,
155 specifies that
156 .B start\-stop\-daemon
157 is to check whether the process(es)
158 do finish. It will check repeatedly whether any matching processes
159 are running, until none are. If the processes do not exit it will
160 then take further action as determined by the schedule.
161
162 If
163 .I timeout
164 is specified instead of
165 .IR schedule ,
166 then the schedule
167 .IB signal / timeout /KILL/ timeout
168 is used, where
169 .I signal
170 is the signal specified with
171 .BR \-\-signal .
172
173 .I schedule
174 is a list of at least two items separated by slashes
175 .RB ( / );
176 each item may be
177 .BI \- signal-number
178 or [\fB\-\fP]\fIsignal-name\fP,
179 which means to send that signal,
180 or
181 .IR timeout ,
182 which means to wait that many seconds for processes to
183 exit,
184 or
185 .BR forever ,
186 which means to repeat the rest of the schedule forever if
187 necessary.
188
189 If the end of the schedule is reached and
190 .BR forever
191 is not specified, then
192 .B start\-stop\-daemon
193 exits with error status 2.
194 If a schedule is specified, then any signal specified
195 with
196 .B \-\-signal
197 is ignored.
198 .TP
199 .BR \-a ", " \-\-startas " \fIpathname\fP"
200 With
201 .BR \-\-start ,
202 start the process specified by
203 .IR pathname .
204 If not specified, defaults to the argument given to
205 .BR \-\-exec .
206 .TP
207 .BR \-t ", " \-\-test
208 Print actions that would be taken and set appropriate return value,
209 but take no action.
210 .TP
211 .BR \-o ", " \-\-oknodo
212 Return exit status 0 instead of 1 if no actions are (would be) taken.
213 .TP
214 .BR \-q ", " \-\-quiet
215 Do not print informational messages; only display error messages.
216 .TP
217 .BR \-c ", " \-\-chuid " \fIusername\fR|\fIuid\fP[\fB:\fP\fIgroup\fR|\fIgid\fP]"
218 Change to this username/uid before starting the process. You can also
219 specify a group by appending a
220 .BR : ,
221 then the group or gid in the same way
222 as you would for the \fBchown\fP(1) command (\fIuser\fP\fB:\fP\fIgroup\fP).
223 If a user is specified without a group, the primary GID for that user is used.
224 When using this option
225 you must realize that the primary and supplemental groups are set as well,
226 even if the
227 .B \-\-group
228 option is not specified. The
229 .B \-\-group
230 option is only for
231 groups that the user isn't normally a member of (like adding per process
232 group membership for generic users like
233 .BR nobody ).
234 .TP
235 .BR \-r ", " \-\-chroot " \fIroot\fP"
236 Chdir and chroot to
237 .I root
238 before starting the process. Please note that the pidfile is also written
239 after the chroot.
240 .TP
241 .BR \-d ", " \-\-chdir " \fIpath\fP"
242 Chdir to
243 .I path
244 before starting the process. This is done after the chroot if the
245 \fB\-r\fP|\fB\-\-chroot\fP option is set. When not specified,
246 .B start\-stop\-daemon
247 will chdir to the root directory before starting the process.
248 .TP
249 .BR \-b ", " \-\-background
250 Typically used with programs that don't detach on their own. This option
251 will force
252 .B start\-stop\-daemon
253 to fork before starting the process, and force it into the background.
254 .B Warning: start\-stop\-daemon
255 cannot check the exit status if the process fails to execute for
256 .B any
257 reason. This is a last resort, and is only meant for programs that either
258 make no sense forking on their own, or where it's not feasible to add the
259 code for them to do this themselves.
260 .TP
261 .BR \-C ", " \-\-no\-close
262 Do not close any file descriptor when forcing the daemon into the background
263 (since version 1.16.5).
264 Used for debugging purposes to see the process output, or to redirect file
265 descriptors to log the process output.
266 Only relevant when using \fB\-\-background\fP.
267 .TP
268 .BR \-N ", " \-\-nicelevel " \fIint\fP"
269 This alters the priority of the process before starting it.
270 .TP
271 .BR \-P ", " \-\-procsched " \fIpolicy\fP\fB:\fP\fIpriority\fP"
272 This alters the process scheduler policy and priority of the process before
273 starting it (since version 1.15.0).
274 The priority can be optionally specified by appending a \fB:\fP
275 followed by the value. The default \fIpriority\fP is 0. The currently
276 supported policy values are \fBother\fP, \fBfifo\fP and \fBrr\fP.
277 .TP
278 .BR \-I ", " \-\-iosched " \fIclass\fP\fB:\fP\fIpriority\fP"
279 This alters the IO scheduler class and priority of the process before starting
280 it (since version 1.15.0).
281 The priority can be optionally specified by appending a \fB:\fP followed
282 by the value. The default \fIpriority\fP is 4, unless \fIclass\fP is \fBidle\fP,
283 then \fIpriority\fP will always be 7. The currently supported values for
284 \fIclass\fP are \fBidle\fP, \fBbest-effort\fP and \fBreal-time\fP.
285 .TP
286 .BR \-k ", " \-\-umask " \fImask\fP"
287 This sets the umask of the process before starting it (since version 1.13.22).
288 .TP
289 .BR \-m ", " \-\-make\-pidfile
290 Used when starting a program that does not create its own pid file. This
291 option will make
292 .B start\-stop\-daemon
293 create the file referenced with
294 .B \-\-pidfile
295 and place the pid into it just before executing the process. Note, the
296 file will only be removed when stopping the program if
297 \fB\-\-remove\-pidfile\fP is used.
298 .B Note:
299 This feature may not work in all cases. Most notably when the program
300 being executed forks from its main process. Because of this, it is usually
301 only useful when combined with the
302 .B \-\-background
303 option.
304 .TP
305 .B \-\-remove\-pidfile
306 Used when stopping a program that does not remove its own pid file
307 (since version 1.17.19).
308 This option will make
309 .B start\-stop\-daemon
310 remove the file referenced with
311 .B \-\-pidfile
312 after terminating the process.
313 .TP
314 .BR \-v ", " \-\-verbose
315 Print verbose informational messages.
316 .
317 .SH EXIT STATUS
318 .TP
319 .B 0
320 The requested action was performed. If
321 .B \-\-oknodo
322 was specified, it's also possible that nothing had to be done.
323 This can happen when
324 .B \-\-start
325 was specified and a matching process was already running, or when
326 .B \-\-stop
327 was specified and there were no matching processes.
328 .TP
329 .B 1
330 If
331 .B \-\-oknodo
332 was not specified and nothing was done.
333 .TP
334 .B 2
335 If
336 .B \-\-stop
337 and
338 .B \-\-retry
339 were specified, but the end of the schedule was reached and the processes were
340 still running.
341 .TP
342 .B 3
343 Any other error.
344 .PP
345 When using the \fB\-\-status\fP command, the following status codes are
346 returned:
347 .TP
348 .B 0
349 Program is running.
350 .TP
351 .B 1
352 Program is not running and the pid file exists.
353 .TP
354 .B 3
355 Program is not running.
356 .TP
357 .B 4
358 Unable to determine program status.
359 .
360 .SH EXAMPLE
361 Start the \fBfood\fP daemon, unless one is already running (a process named
362 food, running as user food, with pid in food.pid):
363 .IP
364 .nf
365 start\-stop\-daemon \-\-start \-\-oknodo \-\-user food \-\-name food \\
366 \-\-pidfile /run/food.pid \-\-startas /usr/sbin/food \\
367 \-\-chuid food \-\- \-\-daemon
368 .fi
369 .PP
370 Send \fBSIGTERM\fP to \fBfood\fP and wait up to 5 seconds for it to stop:
371 .IP
372 .nf
373 start\-stop\-daemon \-\-stop \-\-oknodo \-\-user food \-\-name food \\
374 \-\-pidfile /run/food.pid \-\-retry 5
375 .fi
376 .PP
377 Demonstration of a custom schedule for stopping \fBfood\fP:
378 .IP
379 .nf
380 start\-stop\-daemon \-\-stop \-\-oknodo \-\-user food \-\-name food \\
381 \-\-pidfile /run/food.pid \-\-retry=TERM/30/KILL/5
382 .fi
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