start-stop-daemon/start-stop-daemon.8

   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
  12 .\" the Free Software Foundation; either version 2 of the License, or
  13 .\" (at your option) any later version.
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  15 .\" This is distributed in the hope that it will be useful,
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  17 .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 .\" GNU General Public License for more details.
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  20 .\" You should have received a copy of the GNU General Public License
  21 .\" along with this program.  If not, see <https://www.gnu.org/licenses/>.
  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