1start-stop-daemon(8) dpkg suite start-stop-daemon(8)
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6 start-stop-daemon - start and stop system daemon programs
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9 start-stop-daemon [option...] command
10
12 start-stop-daemon is used to control the creation and termination of
13 system-level processes. Using one of the matching options,
14 start-stop-daemon can be configured to find existing instances of a
15 running process.
16 Note: unless --pid or --pidfile are specified, start-stop-daemon
18 behaves similar to killall(1). start-stop-daemon will scan the process
19 table looking for any processes which match the process name, parent
20 pid, uid, and/or gid (if specified). Any matching process will prevent
21 --start from starting the daemon. All matching processes will be sent
22 the TERM signal (or the one specified via --signal or --retry) if
23 --stop is specified. For daemons which have long-lived children which
24 need to live through a --stop, you must specify a pidfile.
25
27 -S, --start [--] arguments
28 Check for the existence of a specified process. If such a
29 process exists, start-stop-daemon does nothing, and exits with
30 error status 1 (0 if --oknodo is specified). If such a process
31 does not exist, it starts an instance, using either the
32 executable specified by --exec or, if specified, by --startas.
33 Any arguments given after -- on the command line are passed
34 unmodified to the program being started.
35 -K, --stop
37 Checks for the existence of a specified process. If such a
38 process exists, start-stop-daemon sends it the signal specified
39 by --signal, and exits with error status 0. If such a process
40 does not exist, start-stop-daemon exits with error status 1 (0
41 if --oknodo is specified). If --retry is specified, then
42 start-stop-daemon will check that the process(es) have
43 terminated.
44 -T, --status
46 Check for the existence of a specified process, and returns an
47 exit status code, according to the LSB Init Script Actions
48 (since version 1.16.1).
49 -H, --help
51 Show usage information and exit.
52 -V, --version
54 Show the program version and exit.
55
57 Matching options
58 --pid pid
59 Check for a process with the specified pid (since version
60 1.17.6). The pid must be a number greater than 0.
61 --ppid ppid
63 Check for a process with the specified parent pid ppid (since
64 version 1.17.7). The ppid must be a number greater than 0.
65 -p, --pidfile pid-file
67 Check whether a process has created the file pid-file.
68 Note: using this matching option alone might cause unintended
70 processes to be acted on, if the old process terminated without
71 being able to remove the pid-file.
72 Warning: using this match option with a world-writable pidfile
74 or using it alone with a daemon that writes the pidfile as an
75 unprivileged (non-root) user will be refused with an error
76 (since version 1.19.3) as this is a security risk, because
77 either any user can write to it, or if the daemon gets
78 compromised, the contents of the pidfile cannot be trusted, and
79 then a privileged runner (such as an init script executed as
80 root) would end up acting on any system process. Using
81 /dev/null is exempt from these checks.
82 -x, --exec executable
84 Check for processes that are instances of this executable. The
85 executable argument should be an absolute pathname. Note: this
86 might not work as intended with interpreted scripts, as the
87 executable will point to the interpreter. Take into account
88 processes running from inside a chroot will also be matched, so
89 other match restrictions might be needed.
90 -n, --name process-name
92 Check for processes with the name process-name. The process-name
93 is usually the process filename, but it could have been changed
94 by the process itself. Note: on most systems this information is
95 retrieved from the process comm name from the kernel, which
96 tends to have a relatively short length limit (assuming more
97 than 15 characters is non-portable).
98 -u, --user username|uid
100 Check for processes owned by the user specified by username or
101 uid. Note: using this matching option alone will cause all
102 processes matching the user to be acted on.
103 Generic options
105 -g, --group group|gid
106 Change to group or gid when starting the process.
107 -s, --signal signal
109 With --stop, specifies the signal to send to processes being
110 stopped (default TERM).
111 -R, --retry timeout|schedule
113 With --stop, specifies that start-stop-daemon is to check
114 whether the process(es) do finish. It will check repeatedly
115 whether any matching processes are running, until none are. If
116 the processes do not exit it will then take further action as
117 determined by the schedule.
118 If timeout is specified instead of schedule, then the schedule
120 signal/timeout/KILL/timeout is used, where signal is the signal
121 specified with --signal.
122 schedule is a list of at least two items separated by slashes
124 (/); each item may be -signal-number or [-]signal-name, which
125 means to send that signal, or timeout, which means to wait that
126 many seconds for processes to exit, or forever, which means to
127 repeat the rest of the schedule forever if necessary.
128 If the end of the schedule is reached and forever is not
130 specified, then start-stop-daemon exits with error status 2. If
131 a schedule is specified, then any signal specified with --signal
132 is ignored.
133 -a, --startas pathname
135 With --start, start the process specified by pathname. If not
136 specified, defaults to the argument given to --exec.
137 -t, --test
139 Print actions that would be taken and set appropriate return
140 value, but take no action.
141 -o, --oknodo
143 Return exit status 0 instead of 1 if no actions are (would be)
144 taken.
145 -q, --quiet
147 Do not print informational messages; only display error
148 messages.
149 -c, --chuid username|uid[:group|gid]
151 Change to this username/uid before starting the process. You can
152 also specify a group by appending a :, then the group or gid in
153 the same way as you would for the chown(1) command (user:group).
154 If a user is specified without a group, the primary GID for that
155 user is used. When using this option you must realize that the
156 primary and supplemental groups are set as well, even if the
157 --group option is not specified. The --group option is only for
158 groups that the user isn't normally a member of (like adding per
159 process group membership for generic users like nobody).
160 -r, --chroot root
162 Chdir and chroot to root before starting the process. Please
163 note that the pidfile is also written after the chroot.
164 -d, --chdir path
166 Chdir to path before starting the process. This is done after
167 the chroot if the -r|--chroot option is set. When not specified,
168 start-stop-daemon will chdir to the root directory before
169 starting the process.
170 -b, --background
172 Typically used with programs that don't detach on their own.
173 This option will force start-stop-daemon to fork before starting
174 the process, and force it into the background. Warning:
175 start-stop-daemon cannot check the exit status if the process
176 fails to execute for any reason. This is a last resort, and is
177 only meant for programs that either make no sense forking on
178 their own, or where it's not feasible to add the code for them
179 to do this themselves.
180 --notify-await
182 Wait for the background process to send a readiness notification
183 before considering the service started (since version 1.19.3).
184 This implements parts of the systemd readiness protocol, as
185 specified in the sd_notify(3) man page. The following variables
186 are supported:
187 READY=1
189 The program is ready to give service, so we can exit
190 safely.
191 EXTEND_TIMEOUT_USEC=number
193 The program requests to extend the timeout by number
194 microseconds. This will reset the current timeout to the
195 specified value.
196 ERRNO=number
198 The program is exiting with an error. Do the same and
199 print the user-friendly string for the errno value.
200 --notify-timeouttimeout
202 Set a timeout for the --notify-await option (since version
203 1.19.3). When the timeout is reached, start-stop-daemon will
204 exit with an error code, and no readiness notification will be
205 awaited. The default is 60 seconds.
206 -C, --no-close
208 Do not close any file descriptor when forcing the daemon into
209 the background (since version 1.16.5). Used for debugging
210 purposes to see the process output, or to redirect file
211 descriptors to log the process output. Only relevant when using
212 --background.
213 -N, --nicelevel int
215 This alters the priority of the process before starting it.
216 -P, --procsched policy:priority
218 This alters the process scheduler policy and priority of the
219 process before starting it (since version 1.15.0). The priority
220 can be optionally specified by appending a : followed by the
221 value. The default priority is 0. The currently supported policy
222 values are other, fifo and rr.
223 -I, --iosched class:priority
225 This alters the IO scheduler class and priority of the process
226 before starting it (since version 1.15.0). The priority can be
227 optionally specified by appending a : followed by the value. The
228 default priority is 4, unless class is idle, then priority will
229 always be 7. The currently supported values for class are idle,
230 best-effort and real-time.
231 -k, --umask mask
233 This sets the umask of the process before starting it (since
234 version 1.13.22).
235 -m, --make-pidfile
237 Used when starting a program that does not create its own pid
238 file. This option will make start-stop-daemon create the file
239 referenced with --pidfile and place the pid into it just before
240 executing the process. Note, the file will only be removed when
241 stopping the program if --remove-pidfile is used. Note: This
242 feature may not work in all cases. Most notably when the program
243 being executed forks from its main process. Because of this, it
244 is usually only useful when combined with the --background
245 option.
246 --remove-pidfile
248 Used when stopping a program that does not remove its own pid
249 file (since version 1.17.19). This option will make
250 start-stop-daemon remove the file referenced with --pidfile
251 after terminating the process.
252 -v, --verbose
254 Print verbose informational messages.
255
257 0 The requested action was performed. If --oknodo was specified,
258 it's also possible that nothing had to be done. This can happen
259 when --start was specified and a matching process was already
260 running, or when --stop was specified and there were no matching
261 processes.
262 1 If --oknodo was not specified and nothing was done.
264 2 If --stop and --retry were specified, but the end of the
266 schedule was reached and the processes were still running.
267 3 Any other error.
269 When using the --status command, the following status codes are
271 returned:
272 0 Program is running.
274 1 Program is not running and the pid file exists.
276 3 Program is not running.
278 4 Unable to determine program status.
280
282 Start the food daemon, unless one is already running (a process named
283 food, running as user food, with pid in food.pid):
284 start-stop-daemon --start --oknodo --user food --name food \
286 --pidfile /run/food.pid --startas /usr/sbin/food \
287 --chuid food -- --daemon
288 Send SIGTERM to food and wait up to 5 seconds for it to stop:
290 start-stop-daemon --stop --oknodo --user food --name food \
292 --pidfile /run/food.pid --retry 5
293 Demonstration of a custom schedule for stopping food:
295 start-stop-daemon --stop --oknodo --user food --name food \
297 --pidfile /run/food.pid --retry=TERM/30/KILL/5
2981.19.7 2019-06-03 start-stop-daemon(8)