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023a4f67 | 1 | <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> |
dd1eb43b | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
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4 | |
5 | <!-- | |
6 | This file is part of systemd. | |
7 | ||
8 | Copyright 2010 Lennart Poettering | |
9 | ||
10 | systemd is free software; you can redistribute it and/or modify it | |
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11 | under the terms of the GNU Lesser General Public License as published by |
12 | the Free Software Foundation; either version 2.1 of the License, or | |
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13 | (at your option) any later version. |
14 | ||
15 | systemd is distributed in the hope that it will be useful, but | |
16 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
5430f7f2 | 18 | Lesser General Public License for more details. |
dd1eb43b | 19 | |
5430f7f2 | 20 | You should have received a copy of the GNU Lesser General Public License |
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21 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
22 | --> | |
23 | ||
24 | <refentry id="systemd.exec"> | |
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25 | <refentryinfo> |
26 | <title>systemd.exec</title> | |
27 | <productname>systemd</productname> | |
28 | ||
29 | <authorgroup> | |
30 | <author> | |
31 | <contrib>Developer</contrib> | |
32 | <firstname>Lennart</firstname> | |
33 | <surname>Poettering</surname> | |
34 | <email>lennart@poettering.net</email> | |
35 | </author> | |
36 | </authorgroup> | |
37 | </refentryinfo> | |
38 | ||
39 | <refmeta> | |
40 | <refentrytitle>systemd.exec</refentrytitle> | |
41 | <manvolnum>5</manvolnum> | |
42 | </refmeta> | |
43 | ||
44 | <refnamediv> | |
45 | <refname>systemd.exec</refname> | |
46 | <refpurpose>Execution environment configuration</refpurpose> | |
47 | </refnamediv> | |
48 | ||
49 | <refsynopsisdiv> | |
50 | <para><filename><replaceable>service</replaceable>.service</filename>, | |
51 | <filename><replaceable>socket</replaceable>.socket</filename>, | |
52 | <filename><replaceable>mount</replaceable>.mount</filename>, | |
53 | <filename><replaceable>swap</replaceable>.swap</filename></para> | |
54 | </refsynopsisdiv> | |
55 | ||
56 | <refsect1> | |
57 | <title>Description</title> | |
58 | ||
59 | <para>Unit configuration files for services, sockets, mount | |
60 | points, and swap devices share a subset of configuration options | |
61 | which define the execution environment of spawned | |
62 | processes.</para> | |
63 | ||
64 | <para>This man page lists the configuration options shared by | |
65 | these four unit types. See | |
66 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
67 | for the common options of all unit configuration files, and | |
68 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
69 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
70 | <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
71 | and | |
72 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
73 | for more information on the specific unit configuration files. The | |
74 | execution specific configuration options are configured in the | |
75 | [Service], [Socket], [Mount], or [Swap] sections, depending on the | |
76 | unit type.</para> | |
77 | </refsect1> | |
78 | ||
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79 | <refsect1> |
80 | <title>Automatic Dependencies</title> | |
81 | ||
82 | <para>A few execution parameters result in additional, automatic | |
83 | dependencies to be added.</para> | |
84 | ||
85 | <para>Units with <varname>WorkingDirectory=</varname> or | |
86 | <varname>RootDirectory=</varname> set automatically gain | |
87 | dependencies of type <varname>Requires=</varname> and | |
88 | <varname>After=</varname> on all mount units required to access | |
89 | the specified paths. This is equivalent to having them listed | |
90 | explicitly in <varname>RequiresMountsFor=</varname>.</para> | |
91 | ||
92 | <para>Similar, units with <varname>PrivateTmp=</varname> enabled | |
93 | automatically get mount unit dependencies for all mounts | |
94 | required to access <filename>/tmp</filename> and | |
95 | <filename>/var/tmp</filename>.</para> | |
96 | ||
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97 | <para>Units whose standard output or error output is connected to <option>journal</option>, <option>syslog</option> |
98 | or <option>kmsg</option> (or their combinations with console output, see below) automatically acquire dependencies | |
99 | of type <varname>After=</varname> on <filename>systemd-journald.socket</filename>.</para> | |
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100 | </refsect1> |
101 | ||
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102 | <refsect1> |
103 | <title>Options</title> | |
104 | ||
105 | <variablelist class='unit-directives'> | |
106 | ||
107 | <varlistentry> | |
108 | <term><varname>WorkingDirectory=</varname></term> | |
109 | ||
043cc715 AP |
110 | <listitem><para>Takes a directory path relative to the service's root |
111 | directory specified by <varname>RootDirectory=</varname>, or the | |
5f5d8eab | 112 | special value <literal>~</literal>. Sets the working directory |
b938cb90 | 113 | for executed processes. If set to <literal>~</literal>, the |
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114 | home directory of the user specified in |
115 | <varname>User=</varname> is used. If not set, defaults to the | |
116 | root directory when systemd is running as a system instance | |
117 | and the respective user's home directory if run as user. If | |
118 | the setting is prefixed with the <literal>-</literal> | |
119 | character, a missing working directory is not considered | |
043cc715 AP |
120 | fatal. If <varname>RootDirectory=</varname> is not set, then |
121 | <varname>WorkingDirectory=</varname> is relative to the root of | |
122 | the system running the service manager. | |
123 | Note that setting this parameter might result in | |
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124 | additional dependencies to be added to the unit (see |
125 | above).</para></listitem> | |
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126 | </varlistentry> |
127 | ||
128 | <varlistentry> | |
129 | <term><varname>RootDirectory=</varname></term> | |
130 | ||
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131 | <listitem><para>Takes a directory path relative to the host's root directory |
132 | (i.e. the root of the system running the service manager). Sets the | |
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133 | root directory for executed processes, with the <citerefentry |
134 | project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
798d3a52 | 135 | system call. If this is used, it must be ensured that the |
5f5d8eab | 136 | process binary and all its auxiliary files are available in |
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137 | the <function>chroot()</function> jail. Note that setting this |
138 | parameter might result in additional dependencies to be added | |
139 | to the unit (see above).</para></listitem> | |
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140 | </varlistentry> |
141 | ||
142 | <varlistentry> | |
143 | <term><varname>User=</varname></term> | |
144 | <term><varname>Group=</varname></term> | |
145 | ||
146 | <listitem><para>Sets the Unix user or group that the processes | |
147 | are executed as, respectively. Takes a single user or group | |
148 | name or ID as argument. If no group is set, the default group | |
43eb109a | 149 | of the user is chosen. These do not affect commands prefixed with <literal>+</literal>.</para></listitem> |
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150 | </varlistentry> |
151 | ||
152 | <varlistentry> | |
153 | <term><varname>SupplementaryGroups=</varname></term> | |
154 | ||
155 | <listitem><para>Sets the supplementary Unix groups the | |
156 | processes are executed as. This takes a space-separated list | |
157 | of group names or IDs. This option may be specified more than | |
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158 | once, in which case all listed groups are set as supplementary |
159 | groups. When the empty string is assigned, the list of | |
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160 | supplementary groups is reset, and all assignments prior to |
161 | this one will have no effect. In any way, this option does not | |
162 | override, but extends the list of supplementary groups | |
163 | configured in the system group database for the | |
43eb109a | 164 | user. This does not affect commands prefixed with <literal>+</literal>.</para></listitem> |
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165 | </varlistentry> |
166 | ||
167 | <varlistentry> | |
168 | <term><varname>Nice=</varname></term> | |
169 | ||
170 | <listitem><para>Sets the default nice level (scheduling | |
171 | priority) for executed processes. Takes an integer between -20 | |
172 | (highest priority) and 19 (lowest priority). See | |
173 | <citerefentry><refentrytitle>setpriority</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
174 | for details.</para></listitem> | |
175 | </varlistentry> | |
176 | ||
177 | <varlistentry> | |
178 | <term><varname>OOMScoreAdjust=</varname></term> | |
179 | ||
180 | <listitem><para>Sets the adjustment level for the | |
181 | Out-Of-Memory killer for executed processes. Takes an integer | |
182 | between -1000 (to disable OOM killing for this process) and | |
183 | 1000 (to make killing of this process under memory pressure | |
184 | very likely). See <ulink | |
185 | url="https://www.kernel.org/doc/Documentation/filesystems/proc.txt">proc.txt</ulink> | |
186 | for details.</para></listitem> | |
187 | </varlistentry> | |
188 | ||
189 | <varlistentry> | |
190 | <term><varname>IOSchedulingClass=</varname></term> | |
191 | ||
b938cb90 | 192 | <listitem><para>Sets the I/O scheduling class for executed |
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193 | processes. Takes an integer between 0 and 3 or one of the |
194 | strings <option>none</option>, <option>realtime</option>, | |
195 | <option>best-effort</option> or <option>idle</option>. See | |
196 | <citerefentry><refentrytitle>ioprio_set</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
197 | for details.</para></listitem> | |
198 | </varlistentry> | |
199 | ||
200 | <varlistentry> | |
201 | <term><varname>IOSchedulingPriority=</varname></term> | |
202 | ||
b938cb90 | 203 | <listitem><para>Sets the I/O scheduling priority for executed |
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204 | processes. Takes an integer between 0 (highest priority) and 7 |
205 | (lowest priority). The available priorities depend on the | |
b938cb90 | 206 | selected I/O scheduling class (see above). See |
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207 | <citerefentry><refentrytitle>ioprio_set</refentrytitle><manvolnum>2</manvolnum></citerefentry> |
208 | for details.</para></listitem> | |
209 | </varlistentry> | |
210 | ||
211 | <varlistentry> | |
212 | <term><varname>CPUSchedulingPolicy=</varname></term> | |
213 | ||
214 | <listitem><para>Sets the CPU scheduling policy for executed | |
215 | processes. Takes one of | |
216 | <option>other</option>, | |
217 | <option>batch</option>, | |
218 | <option>idle</option>, | |
219 | <option>fifo</option> or | |
220 | <option>rr</option>. See | |
221 | <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
222 | for details.</para></listitem> | |
223 | </varlistentry> | |
224 | ||
225 | <varlistentry> | |
226 | <term><varname>CPUSchedulingPriority=</varname></term> | |
227 | ||
228 | <listitem><para>Sets the CPU scheduling priority for executed | |
229 | processes. The available priority range depends on the | |
230 | selected CPU scheduling policy (see above). For real-time | |
231 | scheduling policies an integer between 1 (lowest priority) and | |
232 | 99 (highest priority) can be used. See | |
233 | <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
234 | for details. </para></listitem> | |
235 | </varlistentry> | |
236 | ||
237 | <varlistentry> | |
238 | <term><varname>CPUSchedulingResetOnFork=</varname></term> | |
239 | ||
240 | <listitem><para>Takes a boolean argument. If true, elevated | |
241 | CPU scheduling priorities and policies will be reset when the | |
242 | executed processes fork, and can hence not leak into child | |
243 | processes. See | |
244 | <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
245 | for details. Defaults to false.</para></listitem> | |
246 | </varlistentry> | |
247 | ||
248 | <varlistentry> | |
249 | <term><varname>CPUAffinity=</varname></term> | |
250 | ||
251 | <listitem><para>Controls the CPU affinity of the executed | |
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252 | processes. Takes a list of CPU indices or ranges separated by |
253 | either whitespace or commas. CPU ranges are specified by the | |
254 | lower and upper CPU indices separated by a dash. | |
b938cb90 | 255 | This option may be specified more than once, in which case the |
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256 | specified CPU affinity masks are merged. If the empty string |
257 | is assigned, the mask is reset, all assignments prior to this | |
258 | will have no effect. See | |
259 | <citerefentry><refentrytitle>sched_setaffinity</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
260 | for details.</para></listitem> | |
261 | </varlistentry> | |
262 | ||
263 | <varlistentry> | |
264 | <term><varname>UMask=</varname></term> | |
265 | ||
266 | <listitem><para>Controls the file mode creation mask. Takes an | |
267 | access mode in octal notation. See | |
268 | <citerefentry><refentrytitle>umask</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
269 | for details. Defaults to 0022.</para></listitem> | |
270 | </varlistentry> | |
271 | ||
272 | <varlistentry> | |
273 | <term><varname>Environment=</varname></term> | |
274 | ||
275 | <listitem><para>Sets environment variables for executed | |
276 | processes. Takes a space-separated list of variable | |
b938cb90 | 277 | assignments. This option may be specified more than once, in |
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278 | which case all listed variables will be set. If the same |
279 | variable is set twice, the later setting will override the | |
280 | earlier setting. If the empty string is assigned to this | |
281 | option, the list of environment variables is reset, all prior | |
282 | assignments have no effect. Variable expansion is not | |
283 | performed inside the strings, however, specifier expansion is | |
284 | possible. The $ character has no special meaning. If you need | |
285 | to assign a value containing spaces to a variable, use double | |
286 | quotes (") for the assignment.</para> | |
287 | ||
288 | <para>Example: | |
289 | <programlisting>Environment="VAR1=word1 word2" VAR2=word3 "VAR3=$word 5 6"</programlisting> | |
290 | gives three variables <literal>VAR1</literal>, | |
291 | <literal>VAR2</literal>, <literal>VAR3</literal> | |
292 | with the values <literal>word1 word2</literal>, | |
293 | <literal>word3</literal>, <literal>$word 5 6</literal>. | |
294 | </para> | |
295 | ||
296 | <para> | |
297 | See | |
298 | <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
299 | for details about environment variables.</para></listitem> | |
300 | </varlistentry> | |
301 | <varlistentry> | |
302 | <term><varname>EnvironmentFile=</varname></term> | |
303 | <listitem><para>Similar to <varname>Environment=</varname> but | |
304 | reads the environment variables from a text file. The text | |
305 | file should contain new-line-separated variable assignments. | |
8f0d2981 RM |
306 | Empty lines, lines without an <literal>=</literal> separator, |
307 | or lines starting with ; or # will be ignored, | |
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308 | which may be used for commenting. A line ending with a |
309 | backslash will be concatenated with the following one, | |
310 | allowing multiline variable definitions. The parser strips | |
311 | leading and trailing whitespace from the values of | |
312 | assignments, unless you use double quotes (").</para> | |
313 | ||
314 | <para>The argument passed should be an absolute filename or | |
315 | wildcard expression, optionally prefixed with | |
316 | <literal>-</literal>, which indicates that if the file does | |
317 | not exist, it will not be read and no error or warning message | |
318 | is logged. This option may be specified more than once in | |
319 | which case all specified files are read. If the empty string | |
320 | is assigned to this option, the list of file to read is reset, | |
321 | all prior assignments have no effect.</para> | |
322 | ||
323 | <para>The files listed with this directive will be read | |
324 | shortly before the process is executed (more specifically, | |
325 | after all processes from a previous unit state terminated. | |
326 | This means you can generate these files in one unit state, and | |
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327 | read it with this option in the next).</para> |
328 | ||
329 | <para>Settings from these | |
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330 | files override settings made with |
331 | <varname>Environment=</varname>. If the same variable is set | |
332 | twice from these files, the files will be read in the order | |
333 | they are specified and the later setting will override the | |
334 | earlier setting.</para></listitem> | |
335 | </varlistentry> | |
336 | ||
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337 | <varlistentry> |
338 | <term><varname>PassEnvironment=</varname></term> | |
339 | ||
340 | <listitem><para>Pass environment variables from the systemd system | |
341 | manager to executed processes. Takes a space-separated list of variable | |
342 | names. This option may be specified more than once, in which case all | |
343 | listed variables will be set. If the empty string is assigned to this | |
344 | option, the list of environment variables is reset, all prior | |
345 | assignments have no effect. Variables that are not set in the system | |
346 | manager will not be passed and will be silently ignored.</para> | |
347 | ||
348 | <para>Variables passed from this setting are overridden by those passed | |
349 | from <varname>Environment=</varname> or | |
350 | <varname>EnvironmentFile=</varname>.</para> | |
351 | ||
352 | <para>Example: | |
353 | <programlisting>PassEnvironment=VAR1 VAR2 VAR3</programlisting> | |
354 | passes three variables <literal>VAR1</literal>, | |
355 | <literal>VAR2</literal>, <literal>VAR3</literal> | |
356 | with the values set for those variables in PID1.</para> | |
357 | ||
358 | <para> | |
359 | See | |
360 | <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
361 | for details about environment variables.</para></listitem> | |
362 | </varlistentry> | |
363 | ||
798d3a52 ZJS |
364 | <varlistentry> |
365 | <term><varname>StandardInput=</varname></term> | |
366 | <listitem><para>Controls where file descriptor 0 (STDIN) of | |
367 | the executed processes is connected to. Takes one of | |
368 | <option>null</option>, | |
369 | <option>tty</option>, | |
370 | <option>tty-force</option>, | |
371 | <option>tty-fail</option> or | |
372 | <option>socket</option>.</para> | |
373 | ||
374 | <para>If <option>null</option> is selected, standard input | |
375 | will be connected to <filename>/dev/null</filename>, i.e. all | |
376 | read attempts by the process will result in immediate | |
377 | EOF.</para> | |
378 | ||
379 | <para>If <option>tty</option> is selected, standard input is | |
380 | connected to a TTY (as configured by | |
381 | <varname>TTYPath=</varname>, see below) and the executed | |
382 | process becomes the controlling process of the terminal. If | |
383 | the terminal is already being controlled by another process, | |
384 | the executed process waits until the current controlling | |
385 | process releases the terminal.</para> | |
386 | ||
387 | <para><option>tty-force</option> is similar to | |
388 | <option>tty</option>, but the executed process is forcefully | |
389 | and immediately made the controlling process of the terminal, | |
390 | potentially removing previous controlling processes from the | |
391 | terminal.</para> | |
392 | ||
393 | <para><option>tty-fail</option> is similar to | |
394 | <option>tty</option> but if the terminal already has a | |
395 | controlling process start-up of the executed process | |
396 | fails.</para> | |
397 | ||
398 | <para>The <option>socket</option> option is only valid in | |
399 | socket-activated services, and only when the socket | |
400 | configuration file (see | |
401 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
402 | for details) specifies a single socket only. If this option is | |
403 | set, standard input will be connected to the socket the | |
404 | service was activated from, which is primarily useful for | |
405 | compatibility with daemons designed for use with the | |
406 | traditional | |
b5c7d097 | 407 | <citerefentry project='freebsd'><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
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408 | daemon.</para> |
409 | ||
410 | <para>This setting defaults to | |
411 | <option>null</option>.</para></listitem> | |
412 | </varlistentry> | |
c129bd5d | 413 | |
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414 | <varlistentry> |
415 | <term><varname>StandardOutput=</varname></term> | |
416 | <listitem><para>Controls where file descriptor 1 (STDOUT) of | |
417 | the executed processes is connected to. Takes one of | |
418 | <option>inherit</option>, | |
419 | <option>null</option>, | |
420 | <option>tty</option>, | |
421 | <option>journal</option>, | |
422 | <option>syslog</option>, | |
423 | <option>kmsg</option>, | |
424 | <option>journal+console</option>, | |
425 | <option>syslog+console</option>, | |
426 | <option>kmsg+console</option> or | |
427 | <option>socket</option>.</para> | |
428 | ||
429 | <para><option>inherit</option> duplicates the file descriptor | |
430 | of standard input for standard output.</para> | |
431 | ||
432 | <para><option>null</option> connects standard output to | |
433 | <filename>/dev/null</filename>, i.e. everything written to it | |
434 | will be lost.</para> | |
435 | ||
436 | <para><option>tty</option> connects standard output to a tty | |
437 | (as configured via <varname>TTYPath=</varname>, see below). If | |
438 | the TTY is used for output only, the executed process will not | |
439 | become the controlling process of the terminal, and will not | |
440 | fail or wait for other processes to release the | |
441 | terminal.</para> | |
442 | ||
443 | <para><option>journal</option> connects standard output with | |
444 | the journal which is accessible via | |
445 | <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>. | |
446 | Note that everything that is written to syslog or kmsg (see | |
447 | below) is implicitly stored in the journal as well, the | |
448 | specific two options listed below are hence supersets of this | |
449 | one.</para> | |
450 | ||
451 | <para><option>syslog</option> connects standard output to the | |
452 | <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
453 | system syslog service, in addition to the journal. Note that | |
454 | the journal daemon is usually configured to forward everything | |
455 | it receives to syslog anyway, in which case this option is no | |
456 | different from <option>journal</option>.</para> | |
457 | ||
458 | <para><option>kmsg</option> connects standard output with the | |
459 | kernel log buffer which is accessible via | |
460 | <citerefentry project='man-pages'><refentrytitle>dmesg</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
461 | in addition to the journal. The journal daemon might be | |
462 | configured to send all logs to kmsg anyway, in which case this | |
463 | option is no different from <option>journal</option>.</para> | |
464 | ||
465 | <para><option>journal+console</option>, | |
466 | <option>syslog+console</option> and | |
467 | <option>kmsg+console</option> work in a similar way as the | |
468 | three options above but copy the output to the system console | |
469 | as well.</para> | |
470 | ||
471 | <para><option>socket</option> connects standard output to a | |
472 | socket acquired via socket activation. The semantics are | |
473 | similar to the same option of | |
474 | <varname>StandardInput=</varname>.</para> | |
475 | ||
dfe85b38 LP |
476 | <para>If the standard output (or error output, see below) of a unit is connected to the journal, syslog or the |
477 | kernel log buffer, the unit will implicitly gain a dependency of type <varname>After=</varname> on | |
28c75e25 LP |
478 | <filename>systemd-journald.socket</filename> (also see the automatic dependencies section above).</para> |
479 | ||
798d3a52 ZJS |
480 | <para>This setting defaults to the value set with |
481 | <option>DefaultStandardOutput=</option> in | |
482 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
c129bd5d LP |
483 | which defaults to <option>journal</option>. Note that setting |
484 | this parameter might result in additional dependencies to be | |
485 | added to the unit (see above).</para></listitem> | |
798d3a52 | 486 | </varlistentry> |
c129bd5d | 487 | |
798d3a52 ZJS |
488 | <varlistentry> |
489 | <term><varname>StandardError=</varname></term> | |
490 | <listitem><para>Controls where file descriptor 2 (STDERR) of | |
491 | the executed processes is connected to. The available options | |
492 | are identical to those of <varname>StandardOutput=</varname>, | |
493 | with one exception: if set to <option>inherit</option> the | |
494 | file descriptor used for standard output is duplicated for | |
495 | standard error. This setting defaults to the value set with | |
496 | <option>DefaultStandardError=</option> in | |
497 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
c129bd5d LP |
498 | which defaults to <option>inherit</option>. Note that setting |
499 | this parameter might result in additional dependencies to be | |
500 | added to the unit (see above).</para></listitem> | |
798d3a52 | 501 | </varlistentry> |
c129bd5d | 502 | |
798d3a52 ZJS |
503 | <varlistentry> |
504 | <term><varname>TTYPath=</varname></term> | |
505 | <listitem><para>Sets the terminal device node to use if | |
506 | standard input, output, or error are connected to a TTY (see | |
507 | above). Defaults to | |
508 | <filename>/dev/console</filename>.</para></listitem> | |
509 | </varlistentry> | |
510 | <varlistentry> | |
511 | <term><varname>TTYReset=</varname></term> | |
512 | <listitem><para>Reset the terminal device specified with | |
513 | <varname>TTYPath=</varname> before and after execution. | |
514 | Defaults to <literal>no</literal>.</para></listitem> | |
515 | </varlistentry> | |
516 | <varlistentry> | |
517 | <term><varname>TTYVHangup=</varname></term> | |
518 | <listitem><para>Disconnect all clients which have opened the | |
519 | terminal device specified with <varname>TTYPath=</varname> | |
520 | before and after execution. Defaults to | |
521 | <literal>no</literal>.</para></listitem> | |
522 | </varlistentry> | |
523 | <varlistentry> | |
524 | <term><varname>TTYVTDisallocate=</varname></term> | |
525 | <listitem><para>If the terminal device specified with | |
526 | <varname>TTYPath=</varname> is a virtual console terminal, try | |
527 | to deallocate the TTY before and after execution. This ensures | |
528 | that the screen and scrollback buffer is cleared. Defaults to | |
529 | <literal>no</literal>.</para></listitem> | |
530 | </varlistentry> | |
531 | <varlistentry> | |
532 | <term><varname>SyslogIdentifier=</varname></term> | |
533 | <listitem><para>Sets the process name to prefix log lines sent | |
534 | to the logging system or the kernel log buffer with. If not | |
535 | set, defaults to the process name of the executed process. | |
536 | This option is only useful when | |
537 | <varname>StandardOutput=</varname> or | |
538 | <varname>StandardError=</varname> are set to | |
539 | <option>syslog</option>, <option>journal</option> or | |
540 | <option>kmsg</option> (or to the same settings in combination | |
541 | with <option>+console</option>).</para></listitem> | |
542 | </varlistentry> | |
543 | <varlistentry> | |
544 | <term><varname>SyslogFacility=</varname></term> | |
545 | <listitem><para>Sets the syslog facility to use when logging | |
546 | to syslog. One of <option>kern</option>, | |
547 | <option>user</option>, <option>mail</option>, | |
548 | <option>daemon</option>, <option>auth</option>, | |
549 | <option>syslog</option>, <option>lpr</option>, | |
550 | <option>news</option>, <option>uucp</option>, | |
551 | <option>cron</option>, <option>authpriv</option>, | |
552 | <option>ftp</option>, <option>local0</option>, | |
553 | <option>local1</option>, <option>local2</option>, | |
554 | <option>local3</option>, <option>local4</option>, | |
555 | <option>local5</option>, <option>local6</option> or | |
556 | <option>local7</option>. See | |
557 | <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
558 | for details. This option is only useful when | |
559 | <varname>StandardOutput=</varname> or | |
560 | <varname>StandardError=</varname> are set to | |
561 | <option>syslog</option>. Defaults to | |
562 | <option>daemon</option>.</para></listitem> | |
563 | </varlistentry> | |
564 | <varlistentry> | |
565 | <term><varname>SyslogLevel=</varname></term> | |
a8eaaee7 | 566 | <listitem><para>The default syslog level to use when logging to |
798d3a52 ZJS |
567 | syslog or the kernel log buffer. One of |
568 | <option>emerg</option>, | |
569 | <option>alert</option>, | |
570 | <option>crit</option>, | |
571 | <option>err</option>, | |
572 | <option>warning</option>, | |
573 | <option>notice</option>, | |
574 | <option>info</option>, | |
575 | <option>debug</option>. See | |
576 | <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
577 | for details. This option is only useful when | |
578 | <varname>StandardOutput=</varname> or | |
579 | <varname>StandardError=</varname> are set to | |
580 | <option>syslog</option> or <option>kmsg</option>. Note that | |
581 | individual lines output by the daemon might be prefixed with a | |
582 | different log level which can be used to override the default | |
583 | log level specified here. The interpretation of these prefixes | |
584 | may be disabled with <varname>SyslogLevelPrefix=</varname>, | |
b938cb90 | 585 | see below. For details, see |
798d3a52 ZJS |
586 | <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>. |
587 | ||
588 | Defaults to | |
589 | <option>info</option>.</para></listitem> | |
590 | </varlistentry> | |
591 | ||
592 | <varlistentry> | |
593 | <term><varname>SyslogLevelPrefix=</varname></term> | |
594 | <listitem><para>Takes a boolean argument. If true and | |
595 | <varname>StandardOutput=</varname> or | |
596 | <varname>StandardError=</varname> are set to | |
597 | <option>syslog</option>, <option>kmsg</option> or | |
598 | <option>journal</option>, log lines written by the executed | |
599 | process that are prefixed with a log level will be passed on | |
600 | to syslog with this log level set but the prefix removed. If | |
601 | set to false, the interpretation of these prefixes is disabled | |
602 | and the logged lines are passed on as-is. For details about | |
603 | this prefixing see | |
604 | <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
605 | Defaults to true.</para></listitem> | |
606 | </varlistentry> | |
607 | ||
608 | <varlistentry> | |
609 | <term><varname>TimerSlackNSec=</varname></term> | |
610 | <listitem><para>Sets the timer slack in nanoseconds for the | |
611 | executed processes. The timer slack controls the accuracy of | |
612 | wake-ups triggered by timers. See | |
613 | <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
614 | for more information. Note that in contrast to most other time | |
615 | span definitions this parameter takes an integer value in | |
616 | nano-seconds if no unit is specified. The usual time units are | |
617 | understood too.</para></listitem> | |
618 | </varlistentry> | |
619 | ||
620 | <varlistentry> | |
621 | <term><varname>LimitCPU=</varname></term> | |
622 | <term><varname>LimitFSIZE=</varname></term> | |
623 | <term><varname>LimitDATA=</varname></term> | |
624 | <term><varname>LimitSTACK=</varname></term> | |
625 | <term><varname>LimitCORE=</varname></term> | |
626 | <term><varname>LimitRSS=</varname></term> | |
627 | <term><varname>LimitNOFILE=</varname></term> | |
628 | <term><varname>LimitAS=</varname></term> | |
629 | <term><varname>LimitNPROC=</varname></term> | |
630 | <term><varname>LimitMEMLOCK=</varname></term> | |
631 | <term><varname>LimitLOCKS=</varname></term> | |
632 | <term><varname>LimitSIGPENDING=</varname></term> | |
633 | <term><varname>LimitMSGQUEUE=</varname></term> | |
634 | <term><varname>LimitNICE=</varname></term> | |
635 | <term><varname>LimitRTPRIO=</varname></term> | |
636 | <term><varname>LimitRTTIME=</varname></term> | |
29857001 LP |
637 | <listitem><para>Set soft and hard limits on various resources for executed processes. See |
638 | <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry> for details on | |
639 | the resource limit concept. Resource limits may be specified in two formats: either as single value to set a | |
640 | specific soft and hard limit to the same value, or as colon-separated pair <option>soft:hard</option> to set | |
641 | both limits individually (e.g. <literal>LimitAS=4G:16G</literal>). Use the string <varname>infinity</varname> | |
642 | to configure no limit on a specific resource. The multiplicative suffixes K, M, G, T, P and E (to the base | |
643 | 1024) may be used for resource limits measured in bytes (e.g. LimitAS=16G). For the limits referring to time | |
644 | values, the usual time units ms, s, min, h and so on may be used (see | |
645 | <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry> for | |
646 | details). Note that if no time unit is specified for <varname>LimitCPU=</varname> the default unit of seconds | |
647 | is implied, while for <varname>LimitRTTIME=</varname> the default unit of microseconds is implied. Also, note | |
648 | that the effective granularity of the limits might influence their enforcement. For example, time limits | |
649 | specified for <varname>LimitCPU=</varname> will be rounded up implicitly to multiples of 1s. For | |
650 | <varname>LimitNICE=</varname> the value may be specified in two syntaxes: if prefixed with <literal>+</literal> | |
651 | or <literal>-</literal>, the value is understood as regular Linux nice value in the range -20..19. If not | |
652 | prefixed like this the value is understood as raw resource limit parameter in the range 0..40 (with 0 being | |
653 | equivalent to 1).</para> | |
a4c18002 LP |
654 | |
655 | <para>Note that most process resource limits configured with | |
656 | these options are per-process, and processes may fork in order | |
657 | to acquire a new set of resources that are accounted | |
658 | independently of the original process, and may thus escape | |
659 | limits set. Also note that <varname>LimitRSS=</varname> is not | |
660 | implemented on Linux, and setting it has no effect. Often it | |
661 | is advisable to prefer the resource controls listed in | |
662 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
663 | over these per-process limits, as they apply to services as a | |
664 | whole, may be altered dynamically at runtime, and are | |
665 | generally more expressive. For example, | |
666 | <varname>MemoryLimit=</varname> is a more powerful (and | |
667 | working) replacement for <varname>LimitRSS=</varname>.</para> | |
798d3a52 ZJS |
668 | |
669 | <table> | |
670 | <title>Limit directives and their equivalent with ulimit</title> | |
671 | ||
a4c18002 | 672 | <tgroup cols='3'> |
798d3a52 ZJS |
673 | <colspec colname='directive' /> |
674 | <colspec colname='equivalent' /> | |
a4c18002 | 675 | <colspec colname='unit' /> |
798d3a52 ZJS |
676 | <thead> |
677 | <row> | |
678 | <entry>Directive</entry> | |
679 | <entry>ulimit equivalent</entry> | |
a4c18002 | 680 | <entry>Unit</entry> |
798d3a52 ZJS |
681 | </row> |
682 | </thead> | |
683 | <tbody> | |
684 | <row> | |
a4c18002 | 685 | <entry>LimitCPU=</entry> |
798d3a52 | 686 | <entry>ulimit -t</entry> |
a4c18002 | 687 | <entry>Seconds</entry> |
798d3a52 ZJS |
688 | </row> |
689 | <row> | |
a4c18002 | 690 | <entry>LimitFSIZE=</entry> |
798d3a52 | 691 | <entry>ulimit -f</entry> |
a4c18002 | 692 | <entry>Bytes</entry> |
798d3a52 ZJS |
693 | </row> |
694 | <row> | |
a4c18002 | 695 | <entry>LimitDATA=</entry> |
798d3a52 | 696 | <entry>ulimit -d</entry> |
a4c18002 | 697 | <entry>Bytes</entry> |
798d3a52 ZJS |
698 | </row> |
699 | <row> | |
a4c18002 | 700 | <entry>LimitSTACK=</entry> |
798d3a52 | 701 | <entry>ulimit -s</entry> |
a4c18002 | 702 | <entry>Bytes</entry> |
798d3a52 ZJS |
703 | </row> |
704 | <row> | |
a4c18002 | 705 | <entry>LimitCORE=</entry> |
798d3a52 | 706 | <entry>ulimit -c</entry> |
a4c18002 | 707 | <entry>Bytes</entry> |
798d3a52 ZJS |
708 | </row> |
709 | <row> | |
a4c18002 | 710 | <entry>LimitRSS=</entry> |
798d3a52 | 711 | <entry>ulimit -m</entry> |
a4c18002 | 712 | <entry>Bytes</entry> |
798d3a52 ZJS |
713 | </row> |
714 | <row> | |
a4c18002 | 715 | <entry>LimitNOFILE=</entry> |
798d3a52 | 716 | <entry>ulimit -n</entry> |
a4c18002 | 717 | <entry>Number of File Descriptors</entry> |
798d3a52 ZJS |
718 | </row> |
719 | <row> | |
a4c18002 | 720 | <entry>LimitAS=</entry> |
798d3a52 | 721 | <entry>ulimit -v</entry> |
a4c18002 | 722 | <entry>Bytes</entry> |
798d3a52 ZJS |
723 | </row> |
724 | <row> | |
a4c18002 | 725 | <entry>LimitNPROC=</entry> |
798d3a52 | 726 | <entry>ulimit -u</entry> |
a4c18002 | 727 | <entry>Number of Processes</entry> |
798d3a52 ZJS |
728 | </row> |
729 | <row> | |
a4c18002 | 730 | <entry>LimitMEMLOCK=</entry> |
798d3a52 | 731 | <entry>ulimit -l</entry> |
a4c18002 | 732 | <entry>Bytes</entry> |
798d3a52 ZJS |
733 | </row> |
734 | <row> | |
a4c18002 | 735 | <entry>LimitLOCKS=</entry> |
798d3a52 | 736 | <entry>ulimit -x</entry> |
a4c18002 | 737 | <entry>Number of Locks</entry> |
798d3a52 ZJS |
738 | </row> |
739 | <row> | |
a4c18002 | 740 | <entry>LimitSIGPENDING=</entry> |
798d3a52 | 741 | <entry>ulimit -i</entry> |
a4c18002 | 742 | <entry>Number of Queued Signals</entry> |
798d3a52 ZJS |
743 | </row> |
744 | <row> | |
a4c18002 | 745 | <entry>LimitMSGQUEUE=</entry> |
798d3a52 | 746 | <entry>ulimit -q</entry> |
a4c18002 | 747 | <entry>Bytes</entry> |
798d3a52 ZJS |
748 | </row> |
749 | <row> | |
a4c18002 | 750 | <entry>LimitNICE=</entry> |
798d3a52 | 751 | <entry>ulimit -e</entry> |
a4c18002 | 752 | <entry>Nice Level</entry> |
798d3a52 ZJS |
753 | </row> |
754 | <row> | |
a4c18002 | 755 | <entry>LimitRTPRIO=</entry> |
798d3a52 | 756 | <entry>ulimit -r</entry> |
a4c18002 | 757 | <entry>Realtime Priority</entry> |
798d3a52 ZJS |
758 | </row> |
759 | <row> | |
a4c18002 | 760 | <entry>LimitRTTIME=</entry> |
798d3a52 | 761 | <entry>No equivalent</entry> |
a4c18002 | 762 | <entry>Microseconds</entry> |
798d3a52 ZJS |
763 | </row> |
764 | </tbody> | |
765 | </tgroup> | |
a4c18002 | 766 | </table></listitem> |
798d3a52 ZJS |
767 | </varlistentry> |
768 | ||
769 | <varlistentry> | |
770 | <term><varname>PAMName=</varname></term> | |
771 | <listitem><para>Sets the PAM service name to set up a session | |
772 | as. If set, the executed process will be registered as a PAM | |
773 | session under the specified service name. This is only useful | |
774 | in conjunction with the <varname>User=</varname> setting. If | |
775 | not set, no PAM session will be opened for the executed | |
776 | processes. See | |
777 | <citerefentry project='man-pages'><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
778 | for details.</para></listitem> | |
779 | </varlistentry> | |
780 | ||
781 | <varlistentry> | |
782 | <term><varname>CapabilityBoundingSet=</varname></term> | |
783 | ||
479050b3 LP |
784 | <listitem><para>Controls which capabilities to include in the capability bounding set for the executed |
785 | process. See <citerefentry | |
786 | project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> for | |
787 | details. Takes a whitespace-separated list of capability names as read by <citerefentry | |
788 | project='mankier'><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
789 | e.g. <constant>CAP_SYS_ADMIN</constant>, <constant>CAP_DAC_OVERRIDE</constant>, | |
790 | <constant>CAP_SYS_PTRACE</constant>. Capabilities listed will be included in the bounding set, all others are | |
791 | removed. If the list of capabilities is prefixed with <literal>~</literal>, all but the listed capabilities | |
792 | will be included, the effect of the assignment inverted. Note that this option also affects the respective | |
793 | capabilities in the effective, permitted and inheritable capability sets. If this option is not used, the | |
794 | capability bounding set is not modified on process execution, hence no limits on the capabilities of the | |
795 | process are enforced. This option may appear more than once, in which case the bounding sets are merged. If the | |
796 | empty string is assigned to this option, the bounding set is reset to the empty capability set, and all prior | |
797 | settings have no effect. If set to <literal>~</literal> (without any further argument), the bounding set is | |
cf677fe6 | 798 | reset to the full set of available capabilities, also undoing any previous settings. This does not affect |
43eb109a | 799 | commands prefixed with <literal>+</literal>.</para></listitem> |
798d3a52 ZJS |
800 | </varlistentry> |
801 | ||
ece87975 IP |
802 | <varlistentry> |
803 | <term><varname>AmbientCapabilities=</varname></term> | |
804 | ||
805 | <listitem><para>Controls which capabilities to include in the | |
806 | ambient capability set for the executed process. Takes a | |
807 | whitespace-separated list of capability names as read by | |
808 | <citerefentry project='mankier'><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
809 | e.g. <constant>CAP_SYS_ADMIN</constant>, | |
810 | <constant>CAP_DAC_OVERRIDE</constant>, | |
811 | <constant>CAP_SYS_PTRACE</constant>. This option may appear more than | |
812 | once in which case the ambient capability sets are merged. | |
813 | If the list of capabilities is prefixed with <literal>~</literal>, all | |
814 | but the listed capabilities will be included, the effect of the | |
815 | assignment inverted. If the empty string is | |
816 | assigned to this option, the ambient capability set is reset to | |
817 | the empty capability set, and all prior settings have no effect. | |
818 | If set to <literal>~</literal> (without any further argument), the | |
819 | ambient capability set is reset to the full set of available | |
820 | capabilities, also undoing any previous settings. Note that adding | |
821 | capabilities to ambient capability set adds them to the process's | |
822 | inherited capability set. | |
823 | </para><para> | |
824 | Ambient capability sets are useful if you want to execute a process | |
825 | as a non-privileged user but still want to give it some capabilities. | |
826 | Note that in this case option <constant>keep-caps</constant> is | |
827 | automatically added to <varname>SecureBits=</varname> to retain the | |
cf677fe6 | 828 | capabilities over the user change. <varname>AmbientCapabilities=</varname> does not affect |
43eb109a | 829 | commands prefixed with <literal>+</literal>.</para></listitem> |
ece87975 IP |
830 | </varlistentry> |
831 | ||
798d3a52 ZJS |
832 | <varlistentry> |
833 | <term><varname>SecureBits=</varname></term> | |
834 | <listitem><para>Controls the secure bits set for the executed | |
835 | process. Takes a space-separated combination of options from | |
836 | the following list: | |
837 | <option>keep-caps</option>, | |
838 | <option>keep-caps-locked</option>, | |
839 | <option>no-setuid-fixup</option>, | |
840 | <option>no-setuid-fixup-locked</option>, | |
841 | <option>noroot</option>, and | |
842 | <option>noroot-locked</option>. | |
b938cb90 | 843 | This option may appear more than once, in which case the secure |
798d3a52 | 844 | bits are ORed. If the empty string is assigned to this option, |
43eb109a | 845 | the bits are reset to 0. This does not affect commands prefixed with <literal>+</literal>. |
cf677fe6 | 846 | See <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
798d3a52 ZJS |
847 | for details.</para></listitem> |
848 | </varlistentry> | |
849 | ||
798d3a52 | 850 | <varlistentry> |
2a624c36 AP |
851 | <term><varname>ReadWritePaths=</varname></term> |
852 | <term><varname>ReadOnlyPaths=</varname></term> | |
853 | <term><varname>InaccessiblePaths=</varname></term> | |
798d3a52 ZJS |
854 | |
855 | <listitem><para>Sets up a new file system namespace for | |
856 | executed processes. These options may be used to limit access | |
857 | a process might have to the main file system hierarchy. Each | |
c4b41707 | 858 | setting takes a space-separated list of paths relative to |
043cc715 | 859 | the host's root directory (i.e. the system running the service manager). |
c4b41707 | 860 | Note that if entries contain symlinks, they are resolved from the host's root directory as well. |
2a624c36 AP |
861 | Entries (files or directories) listed in |
862 | <varname>ReadWritePaths=</varname> are accessible from | |
798d3a52 | 863 | within the namespace with the same access rights as from |
c4b41707 | 864 | outside. Entries listed in |
2a624c36 | 865 | <varname>ReadOnlyPaths=</varname> are accessible for |
798d3a52 | 866 | reading only, writing will be refused even if the usual file |
c4b41707 | 867 | access controls would permit this. Entries listed in |
2a624c36 | 868 | <varname>InaccessiblePaths=</varname> will be made |
b50a16af NBS |
869 | inaccessible for processes inside the namespace, and may not |
870 | countain any other mountpoints, including those specified by | |
2a624c36 AP |
871 | <varname>ReadWritePaths=</varname> or |
872 | <varname>ReadOnlyPaths=</varname>. | |
b50a16af | 873 | Note that restricting access with these options does not extend |
c4b41707 AP |
874 | to submounts of a directory that are created later on. |
875 | Non-directory paths can be specified as well. These | |
b938cb90 | 876 | options may be specified more than once, in which case all |
c4b41707 | 877 | paths listed will have limited access from within the |
798d3a52 ZJS |
878 | namespace. If the empty string is assigned to this option, the |
879 | specific list is reset, and all prior assignments have no | |
880 | effect.</para> | |
881 | <para>Paths in | |
2a624c36 | 882 | <varname>ReadOnlyPaths=</varname> |
798d3a52 | 883 | and |
2a624c36 | 884 | <varname>InaccessiblePaths=</varname> |
798d3a52 ZJS |
885 | may be prefixed with |
886 | <literal>-</literal>, in which case | |
887 | they will be ignored when they do not | |
888 | exist. Note that using this | |
889 | setting will disconnect propagation of | |
890 | mounts from the service to the host | |
891 | (propagation in the opposite direction | |
892 | continues to work). This means that | |
893 | this setting may not be used for | |
894 | services which shall be able to | |
895 | install mount points in the main mount | |
896 | namespace.</para></listitem> | |
897 | </varlistentry> | |
898 | ||
899 | <varlistentry> | |
900 | <term><varname>PrivateTmp=</varname></term> | |
901 | ||
902 | <listitem><para>Takes a boolean argument. If true, sets up a | |
903 | new file system namespace for the executed processes and | |
904 | mounts private <filename>/tmp</filename> and | |
905 | <filename>/var/tmp</filename> directories inside it that is | |
906 | not shared by processes outside of the namespace. This is | |
907 | useful to secure access to temporary files of the process, but | |
908 | makes sharing between processes via <filename>/tmp</filename> | |
909 | or <filename>/var/tmp</filename> impossible. If this is | |
910 | enabled, all temporary files created by a service in these | |
911 | directories will be removed after the service is stopped. | |
912 | Defaults to false. It is possible to run two or more units | |
913 | within the same private <filename>/tmp</filename> and | |
914 | <filename>/var/tmp</filename> namespace by using the | |
915 | <varname>JoinsNamespaceOf=</varname> directive, see | |
916 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
917 | for details. Note that using this setting will disconnect | |
918 | propagation of mounts from the service to the host | |
919 | (propagation in the opposite direction continues to work). | |
920 | This means that this setting may not be used for services | |
921 | which shall be able to install mount points in the main mount | |
922 | namespace.</para></listitem> | |
923 | </varlistentry> | |
924 | ||
925 | <varlistentry> | |
926 | <term><varname>PrivateDevices=</varname></term> | |
927 | ||
928 | <listitem><para>Takes a boolean argument. If true, sets up a | |
929 | new /dev namespace for the executed processes and only adds | |
930 | API pseudo devices such as <filename>/dev/null</filename>, | |
931 | <filename>/dev/zero</filename> or | |
932 | <filename>/dev/random</filename> (as well as the pseudo TTY | |
933 | subsystem) to it, but no physical devices such as | |
934 | <filename>/dev/sda</filename>. This is useful to securely turn | |
935 | off physical device access by the executed process. Defaults | |
936 | to false. Enabling this option will also remove | |
937 | <constant>CAP_MKNOD</constant> from the capability bounding | |
938 | set for the unit (see above), and set | |
939 | <varname>DevicePolicy=closed</varname> (see | |
940 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
941 | for details). Note that using this setting will disconnect | |
942 | propagation of mounts from the service to the host | |
943 | (propagation in the opposite direction continues to work). | |
944 | This means that this setting may not be used for services | |
945 | which shall be able to install mount points in the main mount | |
737ba3c8 | 946 | namespace. The /dev namespace will be mounted read-only and 'noexec'. |
947 | The latter may break old programs which try to set up executable | |
948 | memory by using <citerefentry><refentrytitle>mmap</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
949 | of <filename>/dev/zero</filename> instead of using <constant>MAP_ANON</constant>.</para></listitem> | |
798d3a52 ZJS |
950 | </varlistentry> |
951 | ||
952 | <varlistentry> | |
953 | <term><varname>PrivateNetwork=</varname></term> | |
954 | ||
955 | <listitem><para>Takes a boolean argument. If true, sets up a | |
956 | new network namespace for the executed processes and | |
957 | configures only the loopback network device | |
958 | <literal>lo</literal> inside it. No other network devices will | |
959 | be available to the executed process. This is useful to | |
960 | securely turn off network access by the executed process. | |
961 | Defaults to false. It is possible to run two or more units | |
962 | within the same private network namespace by using the | |
963 | <varname>JoinsNamespaceOf=</varname> directive, see | |
964 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
965 | for details. Note that this option will disconnect all socket | |
966 | families from the host, this includes AF_NETLINK and AF_UNIX. | |
967 | The latter has the effect that AF_UNIX sockets in the abstract | |
968 | socket namespace will become unavailable to the processes | |
969 | (however, those located in the file system will continue to be | |
970 | accessible).</para></listitem> | |
971 | </varlistentry> | |
972 | ||
973 | <varlistentry> | |
974 | <term><varname>ProtectSystem=</varname></term> | |
975 | ||
976 | <listitem><para>Takes a boolean argument or | |
977 | <literal>full</literal>. If true, mounts the | |
978 | <filename>/usr</filename> and <filename>/boot</filename> | |
979 | directories read-only for processes invoked by this unit. If | |
980 | set to <literal>full</literal>, the <filename>/etc</filename> | |
981 | directory is mounted read-only, too. This setting ensures that | |
b938cb90 | 982 | any modification of the vendor-supplied operating system (and |
798d3a52 ZJS |
983 | optionally its configuration) is prohibited for the service. |
984 | It is recommended to enable this setting for all long-running | |
985 | services, unless they are involved with system updates or need | |
986 | to modify the operating system in other ways. Note however | |
987 | that processes retaining the CAP_SYS_ADMIN capability can undo | |
988 | the effect of this setting. This setting is hence particularly | |
989 | useful for daemons which have this capability removed, for | |
990 | example with <varname>CapabilityBoundingSet=</varname>. | |
991 | Defaults to off.</para></listitem> | |
992 | </varlistentry> | |
993 | ||
994 | <varlistentry> | |
995 | <term><varname>ProtectHome=</varname></term> | |
996 | ||
997 | <listitem><para>Takes a boolean argument or | |
998 | <literal>read-only</literal>. If true, the directories | |
58331437 CH |
999 | <filename>/home</filename>, <filename>/root</filename> and |
1000 | <filename>/run/user</filename> | |
798d3a52 | 1001 | are made inaccessible and empty for processes invoked by this |
58331437 | 1002 | unit. If set to <literal>read-only</literal>, the three |
798d3a52 ZJS |
1003 | directories are made read-only instead. It is recommended to |
1004 | enable this setting for all long-running services (in | |
1005 | particular network-facing ones), to ensure they cannot get | |
1006 | access to private user data, unless the services actually | |
1007 | require access to the user's private data. Note however that | |
1008 | processes retaining the CAP_SYS_ADMIN capability can undo the | |
1009 | effect of this setting. This setting is hence particularly | |
1010 | useful for daemons which have this capability removed, for | |
1011 | example with <varname>CapabilityBoundingSet=</varname>. | |
1012 | Defaults to off.</para></listitem> | |
1013 | </varlistentry> | |
1014 | ||
1015 | <varlistentry> | |
1016 | <term><varname>MountFlags=</varname></term> | |
1017 | ||
1018 | <listitem><para>Takes a mount propagation flag: | |
1019 | <option>shared</option>, <option>slave</option> or | |
1020 | <option>private</option>, which control whether mounts in the | |
1021 | file system namespace set up for this unit's processes will | |
1022 | receive or propagate mounts or unmounts. See | |
3ba3a79d | 1023 | <citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>2</manvolnum></citerefentry> |
798d3a52 ZJS |
1024 | for details. Defaults to <option>shared</option>. Use |
1025 | <option>shared</option> to ensure that mounts and unmounts are | |
1026 | propagated from the host to the container and vice versa. Use | |
1027 | <option>slave</option> to run processes so that none of their | |
1028 | mounts and unmounts will propagate to the host. Use | |
1029 | <option>private</option> to also ensure that no mounts and | |
1030 | unmounts from the host will propagate into the unit processes' | |
1031 | namespace. Note that <option>slave</option> means that file | |
1032 | systems mounted on the host might stay mounted continuously in | |
1033 | the unit's namespace, and thus keep the device busy. Note that | |
1034 | the file system namespace related options | |
1035 | (<varname>PrivateTmp=</varname>, | |
1036 | <varname>PrivateDevices=</varname>, | |
1037 | <varname>ProtectSystem=</varname>, | |
1038 | <varname>ProtectHome=</varname>, | |
2a624c36 AP |
1039 | <varname>ReadOnlyPaths=</varname>, |
1040 | <varname>InaccessiblePaths=</varname> and | |
1041 | <varname>ReadWritePaths=</varname>) require that mount | |
798d3a52 ZJS |
1042 | and unmount propagation from the unit's file system namespace |
1043 | is disabled, and hence downgrade <option>shared</option> to | |
1044 | <option>slave</option>. </para></listitem> | |
1045 | </varlistentry> | |
1046 | ||
1047 | <varlistentry> | |
1048 | <term><varname>UtmpIdentifier=</varname></term> | |
1049 | ||
1050 | <listitem><para>Takes a four character identifier string for | |
023a4f67 LP |
1051 | an <citerefentry |
1052 | project='man-pages'><refentrytitle>utmp</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
1053 | and wtmp entry for this service. This should only be | |
1054 | set for services such as <command>getty</command> | |
1055 | implementations (such as <citerefentry | |
1056 | project='die-net'><refentrytitle>agetty</refentrytitle><manvolnum>8</manvolnum></citerefentry>) | |
798d3a52 | 1057 | where utmp/wtmp entries must be created and cleared before and |
023a4f67 LP |
1058 | after execution, or for services that shall be executed as if |
1059 | they were run by a <command>getty</command> process (see | |
1060 | below). If the configured string is longer than four | |
798d3a52 ZJS |
1061 | characters, it is truncated and the terminal four characters |
1062 | are used. This setting interprets %I style string | |
1063 | replacements. This setting is unset by default, i.e. no | |
1064 | utmp/wtmp entries are created or cleaned up for this | |
1065 | service.</para></listitem> | |
1066 | </varlistentry> | |
1067 | ||
023a4f67 LP |
1068 | <varlistentry> |
1069 | <term><varname>UtmpMode=</varname></term> | |
1070 | ||
1071 | <listitem><para>Takes one of <literal>init</literal>, | |
1072 | <literal>login</literal> or <literal>user</literal>. If | |
1073 | <varname>UtmpIdentifier=</varname> is set, controls which | |
1074 | type of <citerefentry | |
1075 | project='man-pages'><refentrytitle>utmp</refentrytitle><manvolnum>5</manvolnum></citerefentry>/wtmp | |
1076 | entries for this service are generated. This setting has no | |
1077 | effect unless <varname>UtmpIdentifier=</varname> is set | |
1078 | too. If <literal>init</literal> is set, only an | |
1079 | <constant>INIT_PROCESS</constant> entry is generated and the | |
6cd16034 LP |
1080 | invoked process must implement a |
1081 | <command>getty</command>-compatible utmp/wtmp logic. If | |
1082 | <literal>login</literal> is set, first an | |
a8eaaee7 | 1083 | <constant>INIT_PROCESS</constant> entry, followed by a |
6cd16034 | 1084 | <constant>LOGIN_PROCESS</constant> entry is generated. In |
b938cb90 | 1085 | this case, the invoked process must implement a <citerefentry |
023a4f67 LP |
1086 | project='die-net'><refentrytitle>login</refentrytitle><manvolnum>1</manvolnum></citerefentry>-compatible |
1087 | utmp/wtmp logic. If <literal>user</literal> is set, first an | |
1088 | <constant>INIT_PROCESS</constant> entry, then a | |
a8eaaee7 | 1089 | <constant>LOGIN_PROCESS</constant> entry and finally a |
023a4f67 | 1090 | <constant>USER_PROCESS</constant> entry is generated. In this |
b938cb90 | 1091 | case, the invoked process may be any process that is suitable |
023a4f67 LP |
1092 | to be run as session leader. Defaults to |
1093 | <literal>init</literal>.</para></listitem> | |
1094 | </varlistentry> | |
1095 | ||
798d3a52 ZJS |
1096 | <varlistentry> |
1097 | <term><varname>SELinuxContext=</varname></term> | |
1098 | ||
1099 | <listitem><para>Set the SELinux security context of the | |
1100 | executed process. If set, this will override the automated | |
1101 | domain transition. However, the policy still needs to | |
1102 | authorize the transition. This directive is ignored if SELinux | |
1103 | is disabled. If prefixed by <literal>-</literal>, all errors | |
43eb109a | 1104 | will be ignored. This does not affect commands prefixed with <literal>+</literal>. |
cf677fe6 | 1105 | See <citerefentry project='die-net'><refentrytitle>setexeccon</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
798d3a52 ZJS |
1106 | for details.</para></listitem> |
1107 | </varlistentry> | |
1108 | ||
1109 | <varlistentry> | |
1110 | <term><varname>AppArmorProfile=</varname></term> | |
1111 | ||
1112 | <listitem><para>Takes a profile name as argument. The process | |
1113 | executed by the unit will switch to this profile when started. | |
1114 | Profiles must already be loaded in the kernel, or the unit | |
1115 | will fail. This result in a non operation if AppArmor is not | |
1116 | enabled. If prefixed by <literal>-</literal>, all errors will | |
43eb109a | 1117 | be ignored. This does not affect commands prefixed with <literal>+</literal>.</para></listitem> |
798d3a52 ZJS |
1118 | </varlistentry> |
1119 | ||
1120 | <varlistentry> | |
1121 | <term><varname>SmackProcessLabel=</varname></term> | |
1122 | ||
1123 | <listitem><para>Takes a <option>SMACK64</option> security | |
1124 | label as argument. The process executed by the unit will be | |
1125 | started under this label and SMACK will decide whether the | |
b938cb90 | 1126 | process is allowed to run or not, based on it. The process |
798d3a52 ZJS |
1127 | will continue to run under the label specified here unless the |
1128 | executable has its own <option>SMACK64EXEC</option> label, in | |
1129 | which case the process will transition to run under that | |
1130 | label. When not specified, the label that systemd is running | |
1131 | under is used. This directive is ignored if SMACK is | |
1132 | disabled.</para> | |
1133 | ||
1134 | <para>The value may be prefixed by <literal>-</literal>, in | |
1135 | which case all errors will be ignored. An empty value may be | |
cf677fe6 | 1136 | specified to unset previous assignments. This does not affect |
43eb109a | 1137 | commands prefixed with <literal>+</literal>.</para> |
798d3a52 ZJS |
1138 | </listitem> |
1139 | </varlistentry> | |
1140 | ||
1141 | <varlistentry> | |
1142 | <term><varname>IgnoreSIGPIPE=</varname></term> | |
1143 | ||
1144 | <listitem><para>Takes a boolean argument. If true, causes | |
1145 | <constant>SIGPIPE</constant> to be ignored in the executed | |
1146 | process. Defaults to true because <constant>SIGPIPE</constant> | |
1147 | generally is useful only in shell pipelines.</para></listitem> | |
1148 | </varlistentry> | |
1149 | ||
1150 | <varlistentry> | |
1151 | <term><varname>NoNewPrivileges=</varname></term> | |
1152 | ||
1153 | <listitem><para>Takes a boolean argument. If true, ensures | |
1154 | that the service process and all its children can never gain | |
1155 | new privileges. This option is more powerful than the | |
1156 | respective secure bits flags (see above), as it also prohibits | |
1157 | UID changes of any kind. This is the simplest, most effective | |
1158 | way to ensure that a process and its children can never | |
1159 | elevate privileges again.</para></listitem> | |
1160 | </varlistentry> | |
1161 | ||
1162 | <varlistentry> | |
1163 | <term><varname>SystemCallFilter=</varname></term> | |
1164 | ||
1165 | <listitem><para>Takes a space-separated list of system call | |
1166 | names. If this setting is used, all system calls executed by | |
1167 | the unit processes except for the listed ones will result in | |
1168 | immediate process termination with the | |
1169 | <constant>SIGSYS</constant> signal (whitelisting). If the | |
1170 | first character of the list is <literal>~</literal>, the | |
1171 | effect is inverted: only the listed system calls will result | |
1172 | in immediate process termination (blacklisting). If running in | |
19c0b0b9 | 1173 | user mode, or in system mode, but without the |
008dce38 | 1174 | <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting |
19c0b0b9 | 1175 | <varname>User=nobody</varname>), |
798d3a52 ZJS |
1176 | <varname>NoNewPrivileges=yes</varname> is implied. This |
1177 | feature makes use of the Secure Computing Mode 2 interfaces of | |
1178 | the kernel ('seccomp filtering') and is useful for enforcing a | |
1179 | minimal sandboxing environment. Note that the | |
1180 | <function>execve</function>, | |
1181 | <function>rt_sigreturn</function>, | |
1182 | <function>sigreturn</function>, | |
1183 | <function>exit_group</function>, <function>exit</function> | |
1184 | system calls are implicitly whitelisted and do not need to be | |
b938cb90 | 1185 | listed explicitly. This option may be specified more than once, |
798d3a52 ZJS |
1186 | in which case the filter masks are merged. If the empty string |
1187 | is assigned, the filter is reset, all prior assignments will | |
43eb109a | 1188 | have no effect. This does not affect commands prefixed with <literal>+</literal>.</para> |
798d3a52 ZJS |
1189 | |
1190 | <para>If you specify both types of this option (i.e. | |
1191 | whitelisting and blacklisting), the first encountered will | |
1192 | take precedence and will dictate the default action | |
1193 | (termination or approval of a system call). Then the next | |
1194 | occurrences of this option will add or delete the listed | |
1195 | system calls from the set of the filtered system calls, | |
1196 | depending of its type and the default action. (For example, if | |
1197 | you have started with a whitelisting of | |
1198 | <function>read</function> and <function>write</function>, and | |
1199 | right after it add a blacklisting of | |
1200 | <function>write</function>, then <function>write</function> | |
201c1cc2 TM |
1201 | will be removed from the set.)</para> |
1202 | ||
1203 | <para>As the number of possible system | |
1204 | calls is large, predefined sets of system calls are provided. | |
1205 | A set starts with <literal>@</literal> character, followed by | |
1206 | name of the set. | |
1207 | ||
1208 | <table> | |
1209 | <title>Currently predefined system call sets</title> | |
1210 | ||
1211 | <tgroup cols='2'> | |
1212 | <colspec colname='set' /> | |
1213 | <colspec colname='description' /> | |
1214 | <thead> | |
1215 | <row> | |
1216 | <entry>Set</entry> | |
1217 | <entry>Description</entry> | |
1218 | </row> | |
1219 | </thead> | |
1220 | <tbody> | |
1221 | <row> | |
1222 | <entry>@clock</entry> | |
1f9ac68b LP |
1223 | <entry>System calls for changing the system clock (<citerefentry project='man-pages'><refentrytitle>adjtimex</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>settimeofday</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry> |
1224 | </row> | |
1225 | <row> | |
1226 | <entry>@cpu-emulation</entry> | |
1227 | <entry>System calls for CPU emulation functionality (<citerefentry project='man-pages'><refentrytitle>vm86</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry> | |
1228 | </row> | |
1229 | <row> | |
1230 | <entry>@debug</entry> | |
1231 | <entry>Debugging, performance monitoring and tracing functionality (<citerefentry project='man-pages'><refentrytitle>ptrace</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>perf_event_open</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry> | |
201c1cc2 TM |
1232 | </row> |
1233 | <row> | |
1234 | <entry>@io-event</entry> | |
1f9ac68b | 1235 | <entry>Event loop system calls (<citerefentry project='man-pages'><refentrytitle>poll</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>select</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>epoll</refentrytitle><manvolnum>7</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>eventfd</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry> |
201c1cc2 TM |
1236 | </row> |
1237 | <row> | |
1238 | <entry>@ipc</entry> | |
1f9ac68b LP |
1239 | <entry>SysV IPC, POSIX Message Queues or other IPC (<citerefentry project='man-pages'><refentrytitle>mq_overview</refentrytitle><manvolnum>7</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>svipc</refentrytitle><manvolnum>7</manvolnum></citerefentry>)</entry> |
1240 | </row> | |
1241 | <row> | |
1242 | <entry>@keyring</entry> | |
1243 | <entry>Kernel keyring access (<citerefentry project='man-pages'><refentrytitle>keyctl</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry> | |
201c1cc2 TM |
1244 | </row> |
1245 | <row> | |
1246 | <entry>@module</entry> | |
1f9ac68b | 1247 | <entry>Kernel module control (<citerefentry project='man-pages'><refentrytitle>init_module</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>delete_module</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry> |
201c1cc2 TM |
1248 | </row> |
1249 | <row> | |
1250 | <entry>@mount</entry> | |
1f9ac68b | 1251 | <entry>File system mounting and unmounting (<citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry> |
201c1cc2 TM |
1252 | </row> |
1253 | <row> | |
1254 | <entry>@network-io</entry> | |
1f9ac68b | 1255 | <entry>Socket I/O (including local AF_UNIX): <citerefentry project='man-pages'><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>unix</refentrytitle><manvolnum>7</manvolnum></citerefentry></entry> |
201c1cc2 TM |
1256 | </row> |
1257 | <row> | |
1258 | <entry>@obsolete</entry> | |
1f9ac68b | 1259 | <entry>Unusual, obsolete or unimplemented (<citerefentry project='man-pages'><refentrytitle>create_module</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>gtty</refentrytitle><manvolnum>2</manvolnum></citerefentry>, …)</entry> |
201c1cc2 TM |
1260 | </row> |
1261 | <row> | |
1262 | <entry>@privileged</entry> | |
1f9ac68b | 1263 | <entry>All system calls which need super-user capabilities (<citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>)</entry> |
201c1cc2 TM |
1264 | </row> |
1265 | <row> | |
1266 | <entry>@process</entry> | |
1f9ac68b | 1267 | <entry>Process control, execution, namespaces (<citerefentry project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>kill</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>namespaces</refentrytitle><manvolnum>7</manvolnum></citerefentry>, …</entry> |
201c1cc2 TM |
1268 | </row> |
1269 | <row> | |
1270 | <entry>@raw-io</entry> | |
1f9ac68b | 1271 | <entry>Raw I/O port access (<citerefentry project='man-pages'><refentrytitle>ioperm</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>iopl</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <function>pciconfig_read()</function>, …</entry> |
201c1cc2 TM |
1272 | </row> |
1273 | </tbody> | |
1274 | </tgroup> | |
1275 | </table> | |
1276 | ||
1277 | Note, that as new system calls are added to the kernel, additional system calls might be added to the groups | |
1278 | above, so the contents of the sets may change between systemd versions.</para></listitem> | |
798d3a52 ZJS |
1279 | </varlistentry> |
1280 | ||
1281 | <varlistentry> | |
1282 | <term><varname>SystemCallErrorNumber=</varname></term> | |
1283 | ||
1284 | <listitem><para>Takes an <literal>errno</literal> error number | |
1285 | name to return when the system call filter configured with | |
1286 | <varname>SystemCallFilter=</varname> is triggered, instead of | |
1287 | terminating the process immediately. Takes an error name such | |
1288 | as <constant>EPERM</constant>, <constant>EACCES</constant> or | |
1289 | <constant>EUCLEAN</constant>. When this setting is not used, | |
1290 | or when the empty string is assigned, the process will be | |
1291 | terminated immediately when the filter is | |
1292 | triggered.</para></listitem> | |
1293 | </varlistentry> | |
1294 | ||
1295 | <varlistentry> | |
1296 | <term><varname>SystemCallArchitectures=</varname></term> | |
1297 | ||
b938cb90 | 1298 | <listitem><para>Takes a space-separated list of architecture |
798d3a52 ZJS |
1299 | identifiers to include in the system call filter. The known |
1300 | architecture identifiers are <constant>x86</constant>, | |
1301 | <constant>x86-64</constant>, <constant>x32</constant>, | |
1302 | <constant>arm</constant> as well as the special identifier | |
1303 | <constant>native</constant>. Only system calls of the | |
1304 | specified architectures will be permitted to processes of this | |
1305 | unit. This is an effective way to disable compatibility with | |
1306 | non-native architectures for processes, for example to | |
1307 | prohibit execution of 32-bit x86 binaries on 64-bit x86-64 | |
1308 | systems. The special <constant>native</constant> identifier | |
1309 | implicitly maps to the native architecture of the system (or | |
1310 | more strictly: to the architecture the system manager is | |
19c0b0b9 RC |
1311 | compiled for). If running in user mode, or in system mode, |
1312 | but without the <constant>CAP_SYS_ADMIN</constant> | |
008dce38 | 1313 | capability (e.g. setting <varname>User=nobody</varname>), |
19c0b0b9 | 1314 | <varname>NoNewPrivileges=yes</varname> is implied. Note |
798d3a52 ZJS |
1315 | that setting this option to a non-empty list implies that |
1316 | <constant>native</constant> is included too. By default, this | |
1317 | option is set to the empty list, i.e. no architecture system | |
1318 | call filtering is applied.</para></listitem> | |
1319 | </varlistentry> | |
1320 | ||
1321 | <varlistentry> | |
1322 | <term><varname>RestrictAddressFamilies=</varname></term> | |
1323 | ||
1324 | <listitem><para>Restricts the set of socket address families | |
1325 | accessible to the processes of this unit. Takes a | |
1326 | space-separated list of address family names to whitelist, | |
1327 | such as | |
1328 | <constant>AF_UNIX</constant>, | |
1329 | <constant>AF_INET</constant> or | |
1330 | <constant>AF_INET6</constant>. When | |
1331 | prefixed with <constant>~</constant> the listed address | |
1332 | families will be applied as blacklist, otherwise as whitelist. | |
1333 | Note that this restricts access to the | |
3ba3a79d | 1334 | <citerefentry project='man-pages'><refentrytitle>socket</refentrytitle><manvolnum>2</manvolnum></citerefentry> |
798d3a52 ZJS |
1335 | system call only. Sockets passed into the process by other |
1336 | means (for example, by using socket activation with socket | |
1337 | units, see | |
1338 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>) | |
1339 | are unaffected. Also, sockets created with | |
1340 | <function>socketpair()</function> (which creates connected | |
1341 | AF_UNIX sockets only) are unaffected. Note that this option | |
1342 | has no effect on 32-bit x86 and is ignored (but works | |
19c0b0b9 RC |
1343 | correctly on x86-64). If running in user mode, or in system |
1344 | mode, but without the <constant>CAP_SYS_ADMIN</constant> | |
008dce38 | 1345 | capability (e.g. setting <varname>User=nobody</varname>), |
19c0b0b9 | 1346 | <varname>NoNewPrivileges=yes</varname> is implied. By |
798d3a52 ZJS |
1347 | default, no restriction applies, all address families are |
1348 | accessible to processes. If assigned the empty string, any | |
1349 | previous list changes are undone.</para> | |
1350 | ||
1351 | <para>Use this option to limit exposure of processes to remote | |
1352 | systems, in particular via exotic network protocols. Note that | |
1353 | in most cases, the local <constant>AF_UNIX</constant> address | |
1354 | family should be included in the configured whitelist as it is | |
1355 | frequently used for local communication, including for | |
1356 | <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
43eb109a | 1357 | logging. This does not affect commands prefixed with <literal>+</literal>.</para></listitem> |
798d3a52 ZJS |
1358 | </varlistentry> |
1359 | ||
1360 | <varlistentry> | |
1361 | <term><varname>Personality=</varname></term> | |
1362 | ||
7882632d LP |
1363 | <listitem><para>Controls which kernel architecture <citerefentry |
1364 | project='man-pages'><refentrytitle>uname</refentrytitle><manvolnum>2</manvolnum></citerefentry> shall report, | |
1365 | when invoked by unit processes. Takes one of the architecture identifiers <constant>x86</constant>, | |
1366 | <constant>x86-64</constant>, <constant>ppc</constant>, <constant>ppc-le</constant>, <constant>ppc64</constant>, | |
1367 | <constant>ppc64-le</constant>, <constant>s390</constant> or <constant>s390x</constant>. Which personality | |
1368 | architectures are supported depends on the system architecture. Usually the 64bit versions of the various | |
1369 | system architectures support their immediate 32bit personality architecture counterpart, but no others. For | |
1370 | example, <constant>x86-64</constant> systems support the <constant>x86-64</constant> and | |
1371 | <constant>x86</constant> personalities but no others. The personality feature is useful when running 32-bit | |
1372 | services on a 64-bit host system. If not specified, the personality is left unmodified and thus reflects the | |
1373 | personality of the host system's kernel.</para></listitem> | |
798d3a52 ZJS |
1374 | </varlistentry> |
1375 | ||
1376 | <varlistentry> | |
1377 | <term><varname>RuntimeDirectory=</varname></term> | |
1378 | <term><varname>RuntimeDirectoryMode=</varname></term> | |
1379 | ||
1380 | <listitem><para>Takes a list of directory names. If set, one | |
1381 | or more directories by the specified names will be created | |
1382 | below <filename>/run</filename> (for system services) or below | |
1383 | <varname>$XDG_RUNTIME_DIR</varname> (for user services) when | |
1384 | the unit is started, and removed when the unit is stopped. The | |
1385 | directories will have the access mode specified in | |
1386 | <varname>RuntimeDirectoryMode=</varname>, and will be owned by | |
1387 | the user and group specified in <varname>User=</varname> and | |
1388 | <varname>Group=</varname>. Use this to manage one or more | |
1389 | runtime directories of the unit and bind their lifetime to the | |
1390 | daemon runtime. The specified directory names must be | |
1391 | relative, and may not include a <literal>/</literal>, i.e. | |
1392 | must refer to simple directories to create or remove. This is | |
1393 | particularly useful for unprivileged daemons that cannot | |
1394 | create runtime directories in <filename>/run</filename> due to | |
1395 | lack of privileges, and to make sure the runtime directory is | |
1396 | cleaned up automatically after use. For runtime directories | |
1397 | that require more complex or different configuration or | |
1398 | lifetime guarantees, please consider using | |
1399 | <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> | |
1400 | </varlistentry> | |
1401 | ||
f3e43635 TM |
1402 | <varlistentry> |
1403 | <term><varname>MemoryDenyWriteExecute=</varname></term> | |
1404 | ||
1405 | <listitem><para>Takes a boolean argument. If set, attempts to create memory mappings that are writable and | |
1406 | executable at the same time, or to change existing memory mappings to become executable are prohibited. | |
1407 | Specifically, a system call filter is added that rejects | |
1408 | <citerefentry><refentrytitle>mmap</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
1409 | system calls with both <constant>PROT_EXEC</constant> and <constant>PROT_WRITE</constant> set | |
1410 | and <citerefentry><refentrytitle>mprotect</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
1411 | system calls with <constant>PROT_EXEC</constant> set. Note that this option is incompatible with programs | |
1412 | that generate program code dynamically at runtime, such as JIT execution engines, or programs compiled making | |
1413 | use of the code "trampoline" feature of various C compilers. This option improves service security, as it makes | |
1414 | harder for software exploits to change running code dynamically. | |
1415 | </para></listitem> | |
1416 | </varlistentry> | |
1417 | ||
f4170c67 LP |
1418 | <varlistentry> |
1419 | <term><varname>RestrictRealtime=</varname></term> | |
1420 | ||
1421 | <listitem><para>Takes a boolean argument. If set, any attempts to enable realtime scheduling in a process of | |
1422 | the unit are refused. This restricts access to realtime task scheduling policies such as | |
1423 | <constant>SCHED_FIFO</constant>, <constant>SCHED_RR</constant> or <constant>SCHED_DEADLINE</constant>. See | |
1424 | <citerefentry><refentrytitle>sched</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details about | |
1425 | these scheduling policies. Realtime scheduling policies may be used to monopolize CPU time for longer periods | |
1426 | of time, and may hence be used to lock up or otherwise trigger Denial-of-Service situations on the system. It | |
1427 | is hence recommended to restrict access to realtime scheduling to the few programs that actually require | |
1428 | them. Defaults to off.</para></listitem> | |
1429 | </varlistentry> | |
1430 | ||
798d3a52 ZJS |
1431 | </variablelist> |
1432 | </refsect1> | |
1433 | ||
1434 | <refsect1> | |
1435 | <title>Environment variables in spawned processes</title> | |
1436 | ||
1437 | <para>Processes started by the system are executed in a clean | |
1438 | environment in which select variables listed below are set. System | |
1439 | processes started by systemd do not inherit variables from PID 1, | |
1440 | but processes started by user systemd instances inherit all | |
1441 | environment variables from the user systemd instance. | |
1442 | </para> | |
1443 | ||
1444 | <variablelist class='environment-variables'> | |
1445 | <varlistentry> | |
1446 | <term><varname>$PATH</varname></term> | |
1447 | ||
1448 | <listitem><para>Colon-separated list of directories to use | |
1449 | when launching executables. Systemd uses a fixed value of | |
1450 | <filename>/usr/local/sbin</filename>:<filename>/usr/local/bin</filename>:<filename>/usr/sbin</filename>:<filename>/usr/bin</filename>:<filename>/sbin</filename>:<filename>/bin</filename>. | |
1451 | </para></listitem> | |
1452 | </varlistentry> | |
1453 | ||
1454 | <varlistentry> | |
1455 | <term><varname>$LANG</varname></term> | |
1456 | ||
1457 | <listitem><para>Locale. Can be set in | |
3ba3a79d | 1458 | <citerefentry project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
798d3a52 ZJS |
1459 | or on the kernel command line (see |
1460 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
1461 | and | |
1462 | <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>). | |
1463 | </para></listitem> | |
1464 | </varlistentry> | |
1465 | ||
1466 | <varlistentry> | |
1467 | <term><varname>$USER</varname></term> | |
1468 | <term><varname>$LOGNAME</varname></term> | |
1469 | <term><varname>$HOME</varname></term> | |
1470 | <term><varname>$SHELL</varname></term> | |
1471 | ||
1472 | <listitem><para>User name (twice), home directory, and the | |
1473 | login shell. The variables are set for the units that have | |
1474 | <varname>User=</varname> set, which includes user | |
1475 | <command>systemd</command> instances. See | |
3ba3a79d | 1476 | <citerefentry project='die-net'><refentrytitle>passwd</refentrytitle><manvolnum>5</manvolnum></citerefentry>. |
798d3a52 ZJS |
1477 | </para></listitem> |
1478 | </varlistentry> | |
1479 | ||
1480 | <varlistentry> | |
1481 | <term><varname>$XDG_RUNTIME_DIR</varname></term> | |
1482 | ||
1483 | <listitem><para>The directory for volatile state. Set for the | |
1484 | user <command>systemd</command> instance, and also in user | |
1485 | sessions. See | |
1486 | <citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>. | |
1487 | </para></listitem> | |
1488 | </varlistentry> | |
1489 | ||
1490 | <varlistentry> | |
1491 | <term><varname>$XDG_SESSION_ID</varname></term> | |
1492 | <term><varname>$XDG_SEAT</varname></term> | |
1493 | <term><varname>$XDG_VTNR</varname></term> | |
1494 | ||
1495 | <listitem><para>The identifier of the session, the seat name, | |
1496 | and virtual terminal of the session. Set by | |
1497 | <citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
1498 | for login sessions. <varname>$XDG_SEAT</varname> and | |
1499 | <varname>$XDG_VTNR</varname> will only be set when attached to | |
1500 | a seat and a tty.</para></listitem> | |
1501 | </varlistentry> | |
1502 | ||
1503 | <varlistentry> | |
1504 | <term><varname>$MAINPID</varname></term> | |
1505 | ||
1506 | <listitem><para>The PID of the units main process if it is | |
1507 | known. This is only set for control processes as invoked by | |
1508 | <varname>ExecReload=</varname> and similar. </para></listitem> | |
1509 | </varlistentry> | |
1510 | ||
1511 | <varlistentry> | |
1512 | <term><varname>$MANAGERPID</varname></term> | |
1513 | ||
1514 | <listitem><para>The PID of the user <command>systemd</command> | |
1515 | instance, set for processes spawned by it. </para></listitem> | |
1516 | </varlistentry> | |
1517 | ||
1518 | <varlistentry> | |
1519 | <term><varname>$LISTEN_FDS</varname></term> | |
1520 | <term><varname>$LISTEN_PID</varname></term> | |
5c019cf2 | 1521 | <term><varname>$LISTEN_FDNAMES</varname></term> |
798d3a52 ZJS |
1522 | |
1523 | <listitem><para>Information about file descriptors passed to a | |
1524 | service for socket activation. See | |
1525 | <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
1526 | </para></listitem> | |
1527 | </varlistentry> | |
1528 | ||
5c019cf2 EV |
1529 | <varlistentry> |
1530 | <term><varname>$NOTIFY_SOCKET</varname></term> | |
1531 | ||
1532 | <listitem><para>The socket | |
1533 | <function>sd_notify()</function> talks to. See | |
1534 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
1535 | </para></listitem> | |
1536 | </varlistentry> | |
1537 | ||
1538 | <varlistentry> | |
1539 | <term><varname>$WATCHDOG_PID</varname></term> | |
1540 | <term><varname>$WATCHDOG_USEC</varname></term> | |
1541 | ||
1542 | <listitem><para>Information about watchdog keep-alive notifications. See | |
1543 | <citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
1544 | </para></listitem> | |
1545 | </varlistentry> | |
1546 | ||
798d3a52 ZJS |
1547 | <varlistentry> |
1548 | <term><varname>$TERM</varname></term> | |
1549 | ||
1550 | <listitem><para>Terminal type, set only for units connected to | |
1551 | a terminal (<varname>StandardInput=tty</varname>, | |
1552 | <varname>StandardOutput=tty</varname>, or | |
1553 | <varname>StandardError=tty</varname>). See | |
1554 | <citerefentry project='man-pages'><refentrytitle>termcap</refentrytitle><manvolnum>5</manvolnum></citerefentry>. | |
1555 | </para></listitem> | |
1556 | </varlistentry> | |
7bce046b LP |
1557 | |
1558 | <varlistentry> | |
1559 | <term><varname>$JOURNAL_STREAM</varname></term> | |
1560 | ||
1561 | <listitem><para>If the standard output or standard error output of the executed processes are connected to the | |
1562 | journal (for example, by setting <varname>StandardError=journal</varname>) <varname>$JOURNAL_STREAM</varname> | |
1563 | contains the device and inode numbers of the connection file descriptor, formatted in decimal, separated by a | |
1564 | colon (<literal>:</literal>). This permits invoked processes to safely detect whether their standard output or | |
1565 | standard error output are connected to the journal. The device and inode numbers of the file descriptors should | |
1566 | be compared with the values set in the environment variable to determine whether the process output is still | |
1567 | connected to the journal. Note that it is generally not sufficient to only check whether | |
1568 | <varname>$JOURNAL_STREAM</varname> is set at all as services might invoke external processes replacing their | |
1569 | standard output or standard error output, without unsetting the environment variable.</para> | |
1570 | ||
1571 | <para>This environment variable is primarily useful to allow services to optionally upgrade their used log | |
1572 | protocol to the native journal protocol (using | |
1573 | <citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry> and other | |
1574 | functions) if their standard output or standard error output is connected to the journal anyway, thus enabling | |
1575 | delivery of structured metadata along with logged messages.</para></listitem> | |
1576 | </varlistentry> | |
798d3a52 ZJS |
1577 | </variablelist> |
1578 | ||
1579 | <para>Additional variables may be configured by the following | |
1580 | means: for processes spawned in specific units, use the | |
5c019cf2 EV |
1581 | <varname>Environment=</varname>, <varname>EnvironmentFile=</varname> |
1582 | and <varname>PassEnvironment=</varname> options above; to specify | |
798d3a52 ZJS |
1583 | variables globally, use <varname>DefaultEnvironment=</varname> |
1584 | (see | |
1585 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>) | |
1586 | or the kernel option <varname>systemd.setenv=</varname> (see | |
1587 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>). | |
1588 | Additional variables may also be set through PAM, | |
1589 | cf. <citerefentry project='man-pages'><refentrytitle>pam_env</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
1590 | </refsect1> | |
1591 | ||
1592 | <refsect1> | |
1593 | <title>See Also</title> | |
1594 | <para> | |
1595 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
1596 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
1597 | <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
1598 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
1599 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
1600 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
1601 | <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
1602 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
1603 | <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
1604 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
a4c18002 | 1605 | <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
798d3a52 ZJS |
1606 | <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
1607 | <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
1608 | <citerefentry project='man-pages'><refentrytitle>exec</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
1609 | </para> | |
1610 | </refsect1> | |
dd1eb43b LP |
1611 | |
1612 | </refentry> |