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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"> |
dd1eb43b LP |
4 | |
5 | <!-- | |
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6 | SPDX-License-Identifier: LGPL-2.1+ |
7 | ||
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8 | This file is part of systemd. |
9 | ||
10 | Copyright 2010 Lennart Poettering | |
11 | ||
12 | systemd is free software; you can redistribute it and/or modify it | |
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13 | under the terms of the GNU Lesser General Public License as published by |
14 | the Free Software Foundation; either version 2.1 of the License, or | |
dd1eb43b LP |
15 | (at your option) any later version. |
16 | ||
17 | systemd is distributed in the hope that it will be useful, but | |
18 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
5430f7f2 | 20 | Lesser General Public License for more details. |
dd1eb43b | 21 | |
5430f7f2 | 22 | You should have received a copy of the GNU Lesser General Public License |
dd1eb43b LP |
23 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
24 | --> | |
25 | ||
26 | <refentry id="systemd.exec"> | |
798d3a52 ZJS |
27 | <refentryinfo> |
28 | <title>systemd.exec</title> | |
29 | <productname>systemd</productname> | |
30 | ||
31 | <authorgroup> | |
32 | <author> | |
33 | <contrib>Developer</contrib> | |
34 | <firstname>Lennart</firstname> | |
35 | <surname>Poettering</surname> | |
36 | <email>lennart@poettering.net</email> | |
37 | </author> | |
38 | </authorgroup> | |
39 | </refentryinfo> | |
40 | ||
41 | <refmeta> | |
42 | <refentrytitle>systemd.exec</refentrytitle> | |
43 | <manvolnum>5</manvolnum> | |
44 | </refmeta> | |
45 | ||
46 | <refnamediv> | |
47 | <refname>systemd.exec</refname> | |
48 | <refpurpose>Execution environment configuration</refpurpose> | |
49 | </refnamediv> | |
50 | ||
51 | <refsynopsisdiv> | |
52 | <para><filename><replaceable>service</replaceable>.service</filename>, | |
53 | <filename><replaceable>socket</replaceable>.socket</filename>, | |
54 | <filename><replaceable>mount</replaceable>.mount</filename>, | |
55 | <filename><replaceable>swap</replaceable>.swap</filename></para> | |
56 | </refsynopsisdiv> | |
57 | ||
58 | <refsect1> | |
59 | <title>Description</title> | |
60 | ||
b8afec21 LP |
61 | <para>Unit configuration files for services, sockets, mount points, and swap devices share a subset of |
62 | configuration options which define the execution environment of spawned processes.</para> | |
63 | ||
64 | <para>This man page lists the configuration options shared by these four unit types. See | |
65 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for the common | |
66 | options of all unit configuration files, and | |
798d3a52 ZJS |
67 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
68 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
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69 | <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>, and |
70 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more | |
71 | information on the specific unit configuration files. The execution specific configuration options are configured | |
72 | in the [Service], [Socket], [Mount], or [Swap] sections, depending on the unit type.</para> | |
74b47bbd | 73 | |
c7458f93 | 74 | <para>In addition, options which control resources through Linux Control Groups (cgroups) are listed in |
74b47bbd ZJS |
75 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>. |
76 | Those options complement options listed here.</para> | |
798d3a52 ZJS |
77 | </refsect1> |
78 | ||
c129bd5d | 79 | <refsect1> |
45f09f93 JL |
80 | <title>Implicit Dependencies</title> |
81 | ||
82 | <para>A few execution parameters result in additional, automatic dependencies to be added:</para> | |
83 | ||
84 | <itemizedlist> | |
b8afec21 LP |
85 | <listitem><para>Units with <varname>WorkingDirectory=</varname>, <varname>RootDirectory=</varname>, |
86 | <varname>RootImage=</varname>, <varname>RuntimeDirectory=</varname>, <varname>StateDirectory=</varname>, | |
87 | <varname>CacheDirectory=</varname>, <varname>LogsDirectory=</varname> or | |
88 | <varname>ConfigurationDirectory=</varname> set automatically gain dependencies of type | |
89 | <varname>Requires=</varname> and <varname>After=</varname> on all mount units required to access the specified | |
90 | paths. This is equivalent to having them listed explicitly in | |
91 | <varname>RequiresMountsFor=</varname>.</para></listitem> | |
92 | ||
93 | <listitem><para>Similar, units with <varname>PrivateTmp=</varname> enabled automatically get mount unit | |
94 | dependencies for all mounts required to access <filename>/tmp</filename> and <filename>/var/tmp</filename>. They | |
95 | will also gain an automatic <varname>After=</varname> dependency on | |
45f09f93 JL |
96 | <citerefentry><refentrytitle>systemd-tmpfiles-setup.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para></listitem> |
97 | ||
b8afec21 LP |
98 | <listitem><para>Units whose standard output or error output is connected to <option>journal</option>, |
99 | <option>syslog</option> or <option>kmsg</option> (or their combinations with console output, see below) | |
100 | automatically acquire dependencies of type <varname>After=</varname> on | |
101 | <filename>systemd-journald.socket</filename>.</para></listitem> | |
45f09f93 | 102 | </itemizedlist> |
c129bd5d LP |
103 | </refsect1> |
104 | ||
45f09f93 JL |
105 | <!-- We don't have any default dependency here. --> |
106 | ||
798d3a52 | 107 | <refsect1> |
b8afec21 | 108 | <title>Paths</title> |
798d3a52 ZJS |
109 | |
110 | <variablelist class='unit-directives'> | |
111 | ||
112 | <varlistentry> | |
113 | <term><varname>WorkingDirectory=</varname></term> | |
114 | ||
d251207d LP |
115 | <listitem><para>Takes a directory path relative to the service's root directory specified by |
116 | <varname>RootDirectory=</varname>, or the special value <literal>~</literal>. Sets the working directory for | |
117 | executed processes. If set to <literal>~</literal>, the home directory of the user specified in | |
118 | <varname>User=</varname> is used. If not set, defaults to the root directory when systemd is running as a | |
119 | system instance and the respective user's home directory if run as user. If the setting is prefixed with the | |
120 | <literal>-</literal> character, a missing working directory is not considered fatal. If | |
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121 | <varname>RootDirectory=</varname>/<varname>RootImage=</varname> is not set, then |
122 | <varname>WorkingDirectory=</varname> is relative to the root of the system running the service manager. Note | |
123 | that setting this parameter might result in additional dependencies to be added to the unit (see | |
124 | above).</para></listitem> | |
798d3a52 ZJS |
125 | </varlistentry> |
126 | ||
127 | <varlistentry> | |
128 | <term><varname>RootDirectory=</varname></term> | |
129 | ||
d251207d LP |
130 | <listitem><para>Takes a directory path relative to the host's root directory (i.e. the root of the system |
131 | running the service manager). Sets the root directory for executed processes, with the <citerefentry | |
132 | project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry> system | |
133 | call. If this is used, it must be ensured that the process binary and all its auxiliary files are available in | |
134 | the <function>chroot()</function> jail. Note that setting this parameter might result in additional | |
135 | dependencies to be added to the unit (see above).</para> | |
136 | ||
5d997827 LP |
137 | <para>The <varname>MountAPIVFS=</varname> and <varname>PrivateUsers=</varname> settings are particularly useful |
138 | in conjunction with <varname>RootDirectory=</varname>. For details, see below.</para></listitem> | |
139 | </varlistentry> | |
140 | ||
915e6d16 LP |
141 | <varlistentry> |
142 | <term><varname>RootImage=</varname></term> | |
b8afec21 | 143 | |
915e6d16 | 144 | <listitem><para>Takes a path to a block device node or regular file as argument. This call is similar to |
6cf5a964 | 145 | <varname>RootDirectory=</varname> however mounts a file system hierarchy from a block device node or loopback |
915e6d16 LP |
146 | file instead of a directory. The device node or file system image file needs to contain a file system without a |
147 | partition table, or a file system within an MBR/MS-DOS or GPT partition table with only a single | |
148 | Linux-compatible partition, or a set of file systems within a GPT partition table that follows the <ulink | |
28a0ad81 | 149 | url="https://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/">Discoverable Partitions |
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150 | Specification</ulink>.</para></listitem> |
151 | </varlistentry> | |
152 | ||
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153 | <varlistentry> |
154 | <term><varname>MountAPIVFS=</varname></term> | |
155 | ||
156 | <listitem><para>Takes a boolean argument. If on, a private mount namespace for the unit's processes is created | |
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157 | and the API file systems <filename>/proc</filename>, <filename>/sys</filename>, and <filename>/dev</filename> |
158 | are mounted inside of it, unless they are already mounted. Note that this option has no effect unless used in | |
159 | conjunction with <varname>RootDirectory=</varname>/<varname>RootImage=</varname> as these three mounts are | |
160 | generally mounted in the host anyway, and unless the root directory is changed, the private mount namespace | |
161 | will be a 1:1 copy of the host's, and include these three mounts. Note that the <filename>/dev</filename> file | |
162 | system of the host is bind mounted if this option is used without <varname>PrivateDevices=</varname>. To run | |
163 | the service with a private, minimal version of <filename>/dev/</filename>, combine this option with | |
5d997827 | 164 | <varname>PrivateDevices=</varname>.</para></listitem> |
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165 | </varlistentry> |
166 | ||
b8afec21 LP |
167 | <varlistentry> |
168 | <term><varname>BindPaths=</varname></term> | |
169 | <term><varname>BindReadOnlyPaths=</varname></term> | |
170 | ||
171 | <listitem><para>Configures unit-specific bind mounts. A bind mount makes a particular file or directory | |
172 | available at an additional place in the unit's view of the file system. Any bind mounts created with this | |
173 | option are specific to the unit, and are not visible in the host's mount table. This option expects a | |
174 | whitespace separated list of bind mount definitions. Each definition consists of a colon-separated triple of | |
175 | source path, destination path and option string, where the latter two are optional. If only a source path is | |
176 | specified the source and destination is taken to be the same. The option string may be either | |
177 | <literal>rbind</literal> or <literal>norbind</literal> for configuring a recursive or non-recursive bind | |
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178 | mount. If the destination path is omitted, the option string must be omitted too. |
179 | Each bind mount definition may be prefixed with <literal>-</literal>, in which case it will be ignored | |
180 | when its source path does not exist.</para> | |
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181 | |
182 | <para><varname>BindPaths=</varname> creates regular writable bind mounts (unless the source file system mount | |
183 | is already marked read-only), while <varname>BindReadOnlyPaths=</varname> creates read-only bind mounts. These | |
184 | settings may be used more than once, each usage appends to the unit's list of bind mounts. If the empty string | |
185 | is assigned to either of these two options the entire list of bind mounts defined prior to this is reset. Note | |
186 | that in this case both read-only and regular bind mounts are reset, regardless which of the two settings is | |
187 | used.</para> | |
188 | ||
189 | <para>This option is particularly useful when <varname>RootDirectory=</varname>/<varname>RootImage=</varname> | |
190 | is used. In this case the source path refers to a path on the host file system, while the destination path | |
191 | refers to a path below the root directory of the unit.</para></listitem> | |
192 | </varlistentry> | |
193 | ||
194 | </variablelist> | |
195 | </refsect1> | |
196 | ||
197 | <refsect1> | |
198 | <title>Credentials</title> | |
199 | ||
200 | <variablelist class='unit-directives'> | |
201 | ||
798d3a52 ZJS |
202 | <varlistentry> |
203 | <term><varname>User=</varname></term> | |
204 | <term><varname>Group=</varname></term> | |
205 | ||
29206d46 | 206 | <listitem><para>Set the UNIX user or group that the processes are executed as, respectively. Takes a single |
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207 | user or group name, or a numeric ID as argument. For system services (services run by the system service |
208 | manager, i.e. managed by PID 1) and for user services of the root user (services managed by root's instance of | |
47da760e LP |
209 | <command>systemd --user</command>), the default is <literal>root</literal>, but <varname>User=</varname> may be |
210 | used to specify a different user. For user services of any other user, switching user identity is not | |
211 | permitted, hence the only valid setting is the same user the user's service manager is running as. If no group | |
212 | is set, the default group of the user is used. This setting does not affect commands whose command line is | |
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213 | prefixed with <literal>+</literal>.</para> |
214 | ||
215 | <para>Note that restrictions on the user/group name syntax are enforced: the specified name must consist only | |
216 | of the characters a-z, A-Z, 0-9, <literal>_</literal> and <literal>-</literal>, except for the first character | |
217 | which must be one of a-z, A-Z or <literal>_</literal> (i.e. numbers and <literal>-</literal> are not permitted | |
218 | as first character). The user/group name must have at least one character, and at most 31. These restrictions | |
219 | are enforced in order to avoid ambiguities and to ensure user/group names and unit files remain portable among | |
220 | Linux systems.</para> | |
221 | ||
222 | <para>When used in conjunction with <varname>DynamicUser=</varname> the user/group name specified is | |
223 | dynamically allocated at the time the service is started, and released at the time the service is stopped — | |
224 | unless it is already allocated statically (see below). If <varname>DynamicUser=</varname> is not used the | |
225 | specified user and group must have been created statically in the user database no later than the moment the | |
226 | service is started, for example using the | |
227 | <citerefentry><refentrytitle>sysusers.d</refentrytitle><manvolnum>5</manvolnum></citerefentry> facility, which | |
228 | is applied at boot or package install time.</para></listitem> | |
29206d46 LP |
229 | </varlistentry> |
230 | ||
231 | <varlistentry> | |
232 | <term><varname>DynamicUser=</varname></term> | |
233 | ||
234 | <listitem><para>Takes a boolean parameter. If set, a UNIX user and group pair is allocated dynamically when the | |
235 | unit is started, and released as soon as it is stopped. The user and group will not be added to | |
236 | <filename>/etc/passwd</filename> or <filename>/etc/group</filename>, but are managed transiently during | |
237 | runtime. The <citerefentry><refentrytitle>nss-systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
238 | glibc NSS module provides integration of these dynamic users/groups into the system's user and group | |
239 | databases. The user and group name to use may be configured via <varname>User=</varname> and | |
240 | <varname>Group=</varname> (see above). If these options are not used and dynamic user/group allocation is | |
241 | enabled for a unit, the name of the dynamic user/group is implicitly derived from the unit name. If the unit | |
242 | name without the type suffix qualifies as valid user name it is used directly, otherwise a name incorporating a | |
243 | hash of it is used. If a statically allocated user or group of the configured name already exists, it is used | |
3bd493dc | 244 | and no dynamic user/group is allocated. Note that if <varname>User=</varname> is specified and the static group |
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245 | with the name exists, then it is required that the static user with the name already exists. Similarly, if |
246 | <varname>Group=</varname> is specified and the static user with the name exists, then it is required that the | |
247 | static group with the name already exists. Dynamic users/groups are allocated from the UID/GID range | |
29206d46 LP |
248 | 61184…65519. It is recommended to avoid this range for regular system or login users. At any point in time |
249 | each UID/GID from this range is only assigned to zero or one dynamically allocated users/groups in | |
250 | use. However, UID/GIDs are recycled after a unit is terminated. Care should be taken that any processes running | |
251 | as part of a unit for which dynamic users/groups are enabled do not leave files or directories owned by these | |
252 | users/groups around, as a different unit might get the same UID/GID assigned later on, and thus gain access to | |
63bb64a0 | 253 | these files or directories. If <varname>DynamicUser=</varname> is enabled, <varname>RemoveIPC=</varname>, |
00d9ef85 LP |
254 | <varname>PrivateTmp=</varname> are implied. This ensures that the lifetime of IPC objects and temporary files |
255 | created by the executed processes is bound to the runtime of the service, and hence the lifetime of the dynamic | |
256 | user/group. Since <filename>/tmp</filename> and <filename>/var/tmp</filename> are usually the only | |
257 | world-writable directories on a system this ensures that a unit making use of dynamic user/group allocation | |
63bb64a0 LP |
258 | cannot leave files around after unit termination. Moreover <varname>ProtectSystem=strict</varname> and |
259 | <varname>ProtectHome=read-only</varname> are implied, thus prohibiting the service to write to arbitrary file | |
260 | system locations. In order to allow the service to write to certain directories, they have to be whitelisted | |
4a628360 LP |
261 | using <varname>ReadWritePaths=</varname>, but care must be taken so that UID/GID recycling doesn't create |
262 | security issues involving files created by the service. Use <varname>RuntimeDirectory=</varname> (see below) in | |
263 | order to assign a writable runtime directory to a service, owned by the dynamic user/group and removed | |
264 | automatically when the unit is terminated. Use <varname>StateDirectory=</varname>, | |
265 | <varname>CacheDirectory=</varname> and <varname>LogsDirectory=</varname> in order to assign a set of writable | |
266 | directories for specific purposes to the service in a way that they are protected from vulnerabilities due to | |
267 | UID reuse (see below). Defaults to off.</para></listitem> | |
798d3a52 ZJS |
268 | </varlistentry> |
269 | ||
270 | <varlistentry> | |
271 | <term><varname>SupplementaryGroups=</varname></term> | |
272 | ||
b8afec21 LP |
273 | <listitem><para>Sets the supplementary Unix groups the processes are executed as. This takes a space-separated |
274 | list of group names or IDs. This option may be specified more than once, in which case all listed groups are | |
275 | set as supplementary groups. When the empty string is assigned, the list of supplementary groups is reset, and | |
276 | all assignments prior to this one will have no effect. In any way, this option does not override, but extends | |
277 | the list of supplementary groups configured in the system group database for the user. This does not affect | |
278 | commands prefixed with <literal>+</literal>.</para></listitem> | |
798d3a52 ZJS |
279 | </varlistentry> |
280 | ||
00d9ef85 | 281 | <varlistentry> |
b8afec21 | 282 | <term><varname>PAMName=</varname></term> |
00d9ef85 | 283 | |
b8afec21 LP |
284 | <listitem><para>Sets the PAM service name to set up a session as. If set, the executed process will be |
285 | registered as a PAM session under the specified service name. This is only useful in conjunction with the | |
286 | <varname>User=</varname> setting, and is otherwise ignored. If not set, no PAM session will be opened for the | |
287 | executed processes. See <citerefentry | |
288 | project='man-pages'><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry> for | |
289 | details.</para> | |
00d9ef85 | 290 | |
b8afec21 LP |
291 | <para>Note that for each unit making use of this option a PAM session handler process will be maintained as |
292 | part of the unit and stays around as long as the unit is active, to ensure that appropriate actions can be | |
293 | taken when the unit and hence the PAM session terminates. This process is named <literal>(sd-pam)</literal> and | |
294 | is an immediate child process of the unit's main process.</para> | |
798d3a52 | 295 | |
b8afec21 LP |
296 | <para>Note that when this option is used for a unit it is very likely (depending on PAM configuration) that the |
297 | main unit process will be migrated to its own session scope unit when it is activated. This process will hence | |
298 | be associated with two units: the unit it was originally started from (and for which | |
299 | <varname>PAMName=</varname> was configured), and the session scope unit. Any child processes of that process | |
300 | will however be associated with the session scope unit only. This has implications when used in combination | |
301 | with <varname>NotifyAccess=</varname><option>all</option>, as these child processes will not be able to affect | |
302 | changes in the original unit through notification messages. These messages will be considered belonging to the | |
303 | session scope unit and not the original unit. It is hence not recommended to use <varname>PAMName=</varname> in | |
304 | combination with <varname>NotifyAccess=</varname><option>all</option>.</para> | |
305 | </listitem> | |
798d3a52 ZJS |
306 | </varlistentry> |
307 | ||
b8afec21 LP |
308 | </variablelist> |
309 | </refsect1> | |
798d3a52 | 310 | |
b8afec21 LP |
311 | <refsect1> |
312 | <title>Capabilities</title> | |
798d3a52 | 313 | |
b8afec21 | 314 | <variablelist class='unit-directives'> |
798d3a52 ZJS |
315 | |
316 | <varlistentry> | |
b8afec21 LP |
317 | <term><varname>CapabilityBoundingSet=</varname></term> |
318 | ||
319 | <listitem><para>Controls which capabilities to include in the capability bounding set for the executed | |
320 | process. See <citerefentry | |
321 | project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> for | |
322 | details. Takes a whitespace-separated list of capability names, e.g. <constant>CAP_SYS_ADMIN</constant>, | |
323 | <constant>CAP_DAC_OVERRIDE</constant>, <constant>CAP_SYS_PTRACE</constant>. Capabilities listed will be | |
324 | included in the bounding set, all others are removed. If the list of capabilities is prefixed with | |
325 | <literal>~</literal>, all but the listed capabilities will be included, the effect of the assignment | |
326 | inverted. Note that this option also affects the respective capabilities in the effective, permitted and | |
327 | inheritable capability sets. If this option is not used, the capability bounding set is not modified on process | |
328 | execution, hence no limits on the capabilities of the process are enforced. This option may appear more than | |
329 | once, in which case the bounding sets are merged by <constant>AND</constant>, or by <constant>OR</constant> if | |
330 | the lines are prefixed with <literal>~</literal> (see below). If the empty string is assigned to this option, | |
331 | the bounding set is reset to the empty capability set, and all prior settings have no effect. If set to | |
332 | <literal>~</literal> (without any further argument), the bounding set is reset to the full set of available | |
333 | capabilities, also undoing any previous settings. This does not affect commands prefixed with | |
334 | <literal>+</literal>.</para> | |
798d3a52 | 335 | |
b8afec21 LP |
336 | <para>Example: if a unit has the following, |
337 | <programlisting>CapabilityBoundingSet=CAP_A CAP_B | |
338 | CapabilityBoundingSet=CAP_B CAP_C</programlisting> | |
339 | then <constant>CAP_A</constant>, <constant>CAP_B</constant>, and <constant>CAP_C</constant> are set. | |
340 | If the second line is prefixed with <literal>~</literal>, e.g., | |
341 | <programlisting>CapabilityBoundingSet=CAP_A CAP_B | |
342 | CapabilityBoundingSet=~CAP_B CAP_C</programlisting> | |
343 | then, only <constant>CAP_A</constant> is set.</para></listitem> | |
798d3a52 ZJS |
344 | </varlistentry> |
345 | ||
346 | <varlistentry> | |
b8afec21 | 347 | <term><varname>AmbientCapabilities=</varname></term> |
798d3a52 | 348 | |
b8afec21 LP |
349 | <listitem><para>Controls which capabilities to include in the ambient capability set for the executed |
350 | process. Takes a whitespace-separated list of capability names, e.g. <constant>CAP_SYS_ADMIN</constant>, | |
351 | <constant>CAP_DAC_OVERRIDE</constant>, <constant>CAP_SYS_PTRACE</constant>. This option may appear more than | |
352 | once in which case the ambient capability sets are merged (see the above examples in | |
353 | <varname>CapabilityBoundingSet=</varname>). If the list of capabilities is prefixed with <literal>~</literal>, | |
354 | all but the listed capabilities will be included, the effect of the assignment inverted. If the empty string is | |
355 | assigned to this option, the ambient capability set is reset to the empty capability set, and all prior | |
356 | settings have no effect. If set to <literal>~</literal> (without any further argument), the ambient capability | |
357 | set is reset to the full set of available capabilities, also undoing any previous settings. Note that adding | |
358 | capabilities to ambient capability set adds them to the process's inherited capability set. </para><para> | |
359 | Ambient capability sets are useful if you want to execute a process as a non-privileged user but still want to | |
360 | give it some capabilities. Note that in this case option <constant>keep-caps</constant> is automatically added | |
361 | to <varname>SecureBits=</varname> to retain the capabilities over the user | |
362 | change. <varname>AmbientCapabilities=</varname> does not affect commands prefixed with | |
363 | <literal>+</literal>.</para></listitem> | |
798d3a52 ZJS |
364 | </varlistentry> |
365 | ||
b8afec21 LP |
366 | </variablelist> |
367 | </refsect1> | |
798d3a52 | 368 | |
798d3a52 | 369 | |
b8afec21 LP |
370 | <refsect1> |
371 | <title>Security</title> | |
798d3a52 | 372 | |
b8afec21 | 373 | <variablelist class='unit-directives'> |
798d3a52 ZJS |
374 | |
375 | <varlistentry> | |
b8afec21 | 376 | <term><varname>NoNewPrivileges=</varname></term> |
798d3a52 | 377 | |
b8afec21 LP |
378 | <listitem><para>Takes a boolean argument. If true, ensures that the service process and all its children can |
379 | never gain new privileges through <function>execve()</function> (e.g. via setuid or setgid bits, or filesystem | |
380 | capabilities). This is the simplest and most effective way to ensure that a process and its children can never | |
5af16443 YW |
381 | elevate privileges again. Defaults to false, but certain settings override this and ignore the value of this |
382 | setting. This is the case when <varname>SystemCallFilter=</varname>, | |
b8afec21 LP |
383 | <varname>SystemCallArchitectures=</varname>, <varname>RestrictAddressFamilies=</varname>, |
384 | <varname>RestrictNamespaces=</varname>, <varname>PrivateDevices=</varname>, | |
385 | <varname>ProtectKernelTunables=</varname>, <varname>ProtectKernelModules=</varname>, | |
69b52883 | 386 | <varname>MemoryDenyWriteExecute=</varname>, <varname>RestrictRealtime=</varname>, or |
5af16443 YW |
387 | <varname>LockPersonality=</varname> are specified. Note that even if this setting is overridden by them, |
388 | <command>systemctl show</command> shows the original value of this setting. Also see | |
b8afec21 LP |
389 | <ulink url="https://www.kernel.org/doc/html/latest/userspace-api/no_new_privs.html">No New Privileges |
390 | Flag</ulink>. </para></listitem> | |
798d3a52 ZJS |
391 | </varlistentry> |
392 | ||
393 | <varlistentry> | |
b8afec21 | 394 | <term><varname>SecureBits=</varname></term> |
798d3a52 | 395 | |
b8afec21 LP |
396 | <listitem><para>Controls the secure bits set for the executed process. Takes a space-separated combination of |
397 | options from the following list: <option>keep-caps</option>, <option>keep-caps-locked</option>, | |
398 | <option>no-setuid-fixup</option>, <option>no-setuid-fixup-locked</option>, <option>noroot</option>, and | |
399 | <option>noroot-locked</option>. This option may appear more than once, in which case the secure bits are | |
400 | ORed. If the empty string is assigned to this option, the bits are reset to 0. This does not affect commands | |
401 | prefixed with <literal>+</literal>. See <citerefentry | |
402 | project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> for | |
403 | details.</para></listitem> | |
798d3a52 ZJS |
404 | </varlistentry> |
405 | ||
b8afec21 LP |
406 | </variablelist> |
407 | </refsect1> | |
798d3a52 | 408 | |
b8afec21 LP |
409 | <refsect1> |
410 | <title>Mandatory Access Control</title> | |
411 | <variablelist> | |
798d3a52 | 412 | |
798d3a52 | 413 | <varlistentry> |
b8afec21 LP |
414 | <term><varname>SELinuxContext=</varname></term> |
415 | ||
416 | <listitem><para>Set the SELinux security context of the executed process. If set, this will override the | |
417 | automated domain transition. However, the policy still needs to authorize the transition. This directive is | |
418 | ignored if SELinux is disabled. If prefixed by <literal>-</literal>, all errors will be ignored. This does not | |
419 | affect commands prefixed with <literal>+</literal>. See <citerefentry | |
420 | project='die-net'><refentrytitle>setexeccon</refentrytitle><manvolnum>3</manvolnum></citerefentry> for | |
421 | details.</para></listitem> | |
798d3a52 ZJS |
422 | </varlistentry> |
423 | ||
b4c14404 | 424 | <varlistentry> |
b8afec21 | 425 | <term><varname>AppArmorProfile=</varname></term> |
b4c14404 | 426 | |
b8afec21 LP |
427 | <listitem><para>Takes a profile name as argument. The process executed by the unit will switch to this profile |
428 | when started. Profiles must already be loaded in the kernel, or the unit will fail. This result in a non | |
429 | operation if AppArmor is not enabled. If prefixed by <literal>-</literal>, all errors will be ignored. This | |
430 | does not affect commands prefixed with <literal>+</literal>.</para></listitem> | |
431 | </varlistentry> | |
00819cc1 | 432 | |
b8afec21 LP |
433 | <varlistentry> |
434 | <term><varname>SmackProcessLabel=</varname></term> | |
b4c14404 | 435 | |
b8afec21 LP |
436 | <listitem><para>Takes a <option>SMACK64</option> security label as argument. The process executed by the unit |
437 | will be started under this label and SMACK will decide whether the process is allowed to run or not, based on | |
438 | it. The process will continue to run under the label specified here unless the executable has its own | |
439 | <option>SMACK64EXEC</option> label, in which case the process will transition to run under that label. When not | |
440 | specified, the label that systemd is running under is used. This directive is ignored if SMACK is | |
441 | disabled.</para> | |
b4c14404 | 442 | |
b8afec21 LP |
443 | <para>The value may be prefixed by <literal>-</literal>, in which case all errors will be ignored. An empty |
444 | value may be specified to unset previous assignments. This does not affect commands prefixed with | |
445 | <literal>+</literal>.</para></listitem> | |
b4c14404 FB |
446 | </varlistentry> |
447 | ||
b8afec21 LP |
448 | </variablelist> |
449 | </refsect1> | |
00819cc1 | 450 | |
b8afec21 LP |
451 | <refsect1> |
452 | <title>Process Properties</title> | |
00819cc1 | 453 | |
b8afec21 | 454 | <variablelist> |
00819cc1 | 455 | |
798d3a52 | 456 | <varlistentry> |
b8afec21 LP |
457 | <term><varname>LimitCPU=</varname></term> |
458 | <term><varname>LimitFSIZE=</varname></term> | |
459 | <term><varname>LimitDATA=</varname></term> | |
460 | <term><varname>LimitSTACK=</varname></term> | |
461 | <term><varname>LimitCORE=</varname></term> | |
462 | <term><varname>LimitRSS=</varname></term> | |
463 | <term><varname>LimitNOFILE=</varname></term> | |
464 | <term><varname>LimitAS=</varname></term> | |
465 | <term><varname>LimitNPROC=</varname></term> | |
466 | <term><varname>LimitMEMLOCK=</varname></term> | |
467 | <term><varname>LimitLOCKS=</varname></term> | |
468 | <term><varname>LimitSIGPENDING=</varname></term> | |
469 | <term><varname>LimitMSGQUEUE=</varname></term> | |
470 | <term><varname>LimitNICE=</varname></term> | |
471 | <term><varname>LimitRTPRIO=</varname></term> | |
472 | <term><varname>LimitRTTIME=</varname></term> | |
fc8d0381 | 473 | |
b8afec21 LP |
474 | <listitem><para>Set soft and hard limits on various resources for executed processes. See |
475 | <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry> for details on | |
476 | the resource limit concept. Resource limits may be specified in two formats: either as single value to set a | |
477 | specific soft and hard limit to the same value, or as colon-separated pair <option>soft:hard</option> to set | |
478 | both limits individually (e.g. <literal>LimitAS=4G:16G</literal>). Use the string <option>infinity</option> to | |
479 | configure no limit on a specific resource. The multiplicative suffixes K, M, G, T, P and E (to the base 1024) | |
480 | may be used for resource limits measured in bytes (e.g. LimitAS=16G). For the limits referring to time values, | |
481 | the usual time units ms, s, min, h and so on may be used (see | |
482 | <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry> for | |
483 | details). Note that if no time unit is specified for <varname>LimitCPU=</varname> the default unit of seconds | |
484 | is implied, while for <varname>LimitRTTIME=</varname> the default unit of microseconds is implied. Also, note | |
485 | that the effective granularity of the limits might influence their enforcement. For example, time limits | |
486 | specified for <varname>LimitCPU=</varname> will be rounded up implicitly to multiples of 1s. For | |
487 | <varname>LimitNICE=</varname> the value may be specified in two syntaxes: if prefixed with <literal>+</literal> | |
488 | or <literal>-</literal>, the value is understood as regular Linux nice value in the range -20..19. If not | |
489 | prefixed like this the value is understood as raw resource limit parameter in the range 0..40 (with 0 being | |
490 | equivalent to 1).</para> | |
fc8d0381 | 491 | |
b8afec21 LP |
492 | <para>Note that most process resource limits configured with these options are per-process, and processes may |
493 | fork in order to acquire a new set of resources that are accounted independently of the original process, and | |
494 | may thus escape limits set. Also note that <varname>LimitRSS=</varname> is not implemented on Linux, and | |
495 | setting it has no effect. Often it is advisable to prefer the resource controls listed in | |
496 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
497 | over these per-process limits, as they apply to services as a whole, may be altered dynamically at runtime, and | |
498 | are generally more expressive. For example, <varname>MemoryLimit=</varname> is a more powerful (and working) | |
499 | replacement for <varname>LimitRSS=</varname>.</para> | |
fc8d0381 | 500 | |
b8afec21 LP |
501 | <para>For system units these resource limits may be chosen freely. For user units however (i.e. units run by a |
502 | per-user instance of | |
503 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>), these limits are | |
504 | bound by (possibly more restrictive) per-user limits enforced by the OS.</para> | |
fc8d0381 | 505 | |
b8afec21 LP |
506 | <para>Resource limits not configured explicitly for a unit default to the value configured in the various |
507 | <varname>DefaultLimitCPU=</varname>, <varname>DefaultLimitFSIZE=</varname>, … options available in | |
508 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, and – | |
509 | if not configured there – the kernel or per-user defaults, as defined by the OS (the latter only for user | |
510 | services, see above).</para> | |
fc8d0381 | 511 | |
b8afec21 LP |
512 | <table> |
513 | <title>Resource limit directives, their equivalent <command>ulimit</command> shell commands and the unit used</title> | |
798d3a52 | 514 | |
a4c18002 | 515 | <tgroup cols='3'> |
798d3a52 ZJS |
516 | <colspec colname='directive' /> |
517 | <colspec colname='equivalent' /> | |
a4c18002 | 518 | <colspec colname='unit' /> |
798d3a52 ZJS |
519 | <thead> |
520 | <row> | |
521 | <entry>Directive</entry> | |
f4c9356d | 522 | <entry><command>ulimit</command> equivalent</entry> |
a4c18002 | 523 | <entry>Unit</entry> |
798d3a52 ZJS |
524 | </row> |
525 | </thead> | |
526 | <tbody> | |
527 | <row> | |
a4c18002 | 528 | <entry>LimitCPU=</entry> |
798d3a52 | 529 | <entry>ulimit -t</entry> |
a4c18002 | 530 | <entry>Seconds</entry> |
798d3a52 ZJS |
531 | </row> |
532 | <row> | |
a4c18002 | 533 | <entry>LimitFSIZE=</entry> |
798d3a52 | 534 | <entry>ulimit -f</entry> |
a4c18002 | 535 | <entry>Bytes</entry> |
798d3a52 ZJS |
536 | </row> |
537 | <row> | |
a4c18002 | 538 | <entry>LimitDATA=</entry> |
798d3a52 | 539 | <entry>ulimit -d</entry> |
a4c18002 | 540 | <entry>Bytes</entry> |
798d3a52 ZJS |
541 | </row> |
542 | <row> | |
a4c18002 | 543 | <entry>LimitSTACK=</entry> |
798d3a52 | 544 | <entry>ulimit -s</entry> |
a4c18002 | 545 | <entry>Bytes</entry> |
798d3a52 ZJS |
546 | </row> |
547 | <row> | |
a4c18002 | 548 | <entry>LimitCORE=</entry> |
798d3a52 | 549 | <entry>ulimit -c</entry> |
a4c18002 | 550 | <entry>Bytes</entry> |
798d3a52 ZJS |
551 | </row> |
552 | <row> | |
a4c18002 | 553 | <entry>LimitRSS=</entry> |
798d3a52 | 554 | <entry>ulimit -m</entry> |
a4c18002 | 555 | <entry>Bytes</entry> |
798d3a52 ZJS |
556 | </row> |
557 | <row> | |
a4c18002 | 558 | <entry>LimitNOFILE=</entry> |
798d3a52 | 559 | <entry>ulimit -n</entry> |
a4c18002 | 560 | <entry>Number of File Descriptors</entry> |
798d3a52 ZJS |
561 | </row> |
562 | <row> | |
a4c18002 | 563 | <entry>LimitAS=</entry> |
798d3a52 | 564 | <entry>ulimit -v</entry> |
a4c18002 | 565 | <entry>Bytes</entry> |
798d3a52 ZJS |
566 | </row> |
567 | <row> | |
a4c18002 | 568 | <entry>LimitNPROC=</entry> |
798d3a52 | 569 | <entry>ulimit -u</entry> |
a4c18002 | 570 | <entry>Number of Processes</entry> |
798d3a52 ZJS |
571 | </row> |
572 | <row> | |
a4c18002 | 573 | <entry>LimitMEMLOCK=</entry> |
798d3a52 | 574 | <entry>ulimit -l</entry> |
a4c18002 | 575 | <entry>Bytes</entry> |
798d3a52 ZJS |
576 | </row> |
577 | <row> | |
a4c18002 | 578 | <entry>LimitLOCKS=</entry> |
798d3a52 | 579 | <entry>ulimit -x</entry> |
a4c18002 | 580 | <entry>Number of Locks</entry> |
798d3a52 ZJS |
581 | </row> |
582 | <row> | |
a4c18002 | 583 | <entry>LimitSIGPENDING=</entry> |
798d3a52 | 584 | <entry>ulimit -i</entry> |
a4c18002 | 585 | <entry>Number of Queued Signals</entry> |
798d3a52 ZJS |
586 | </row> |
587 | <row> | |
a4c18002 | 588 | <entry>LimitMSGQUEUE=</entry> |
798d3a52 | 589 | <entry>ulimit -q</entry> |
a4c18002 | 590 | <entry>Bytes</entry> |
798d3a52 ZJS |
591 | </row> |
592 | <row> | |
a4c18002 | 593 | <entry>LimitNICE=</entry> |
798d3a52 | 594 | <entry>ulimit -e</entry> |
a4c18002 | 595 | <entry>Nice Level</entry> |
798d3a52 ZJS |
596 | </row> |
597 | <row> | |
a4c18002 | 598 | <entry>LimitRTPRIO=</entry> |
798d3a52 | 599 | <entry>ulimit -r</entry> |
a4c18002 | 600 | <entry>Realtime Priority</entry> |
798d3a52 ZJS |
601 | </row> |
602 | <row> | |
a4c18002 | 603 | <entry>LimitRTTIME=</entry> |
798d3a52 | 604 | <entry>No equivalent</entry> |
a4c18002 | 605 | <entry>Microseconds</entry> |
798d3a52 ZJS |
606 | </row> |
607 | </tbody> | |
608 | </tgroup> | |
a4c18002 | 609 | </table></listitem> |
798d3a52 ZJS |
610 | </varlistentry> |
611 | ||
612 | <varlistentry> | |
b8afec21 | 613 | <term><varname>UMask=</varname></term> |
9eb484fa | 614 | |
b8afec21 LP |
615 | <listitem><para>Controls the file mode creation mask. Takes an access mode in octal notation. See |
616 | <citerefentry><refentrytitle>umask</refentrytitle><manvolnum>2</manvolnum></citerefentry> for details. Defaults | |
617 | to 0022.</para></listitem> | |
618 | </varlistentry> | |
619 | ||
620 | <varlistentry> | |
621 | <term><varname>KeyringMode=</varname></term> | |
622 | ||
623 | <listitem><para>Controls how the kernel session keyring is set up for the service (see <citerefentry | |
624 | project='man-pages'><refentrytitle>session-keyring</refentrytitle><manvolnum>7</manvolnum></citerefentry> for | |
625 | details on the session keyring). Takes one of <option>inherit</option>, <option>private</option>, | |
626 | <option>shared</option>. If set to <option>inherit</option> no special keyring setup is done, and the kernel's | |
627 | default behaviour is applied. If <option>private</option> is used a new session keyring is allocated when a | |
628 | service process is invoked, and it is not linked up with any user keyring. This is the recommended setting for | |
629 | system services, as this ensures that multiple services running under the same system user ID (in particular | |
630 | the root user) do not share their key material among each other. If <option>shared</option> is used a new | |
631 | session keyring is allocated as for <option>private</option>, but the user keyring of the user configured with | |
632 | <varname>User=</varname> is linked into it, so that keys assigned to the user may be requested by the unit's | |
633 | processes. In this modes multiple units running processes under the same user ID may share key material. Unless | |
634 | <option>inherit</option> is selected the unique invocation ID for the unit (see below) is added as a protected | |
635 | key by the name <literal>invocation_id</literal> to the newly created session keyring. Defaults to | |
636 | <option>private</option> for the system service manager and to <option>inherit</option> for the user service | |
637 | manager.</para></listitem> | |
638 | </varlistentry> | |
639 | ||
640 | <varlistentry> | |
641 | <term><varname>OOMScoreAdjust=</varname></term> | |
642 | ||
643 | <listitem><para>Sets the adjustment level for the Out-Of-Memory killer for executed processes. Takes an integer | |
644 | between -1000 (to disable OOM killing for this process) and 1000 (to make killing of this process under memory | |
645 | pressure very likely). See <ulink | |
646 | url="https://www.kernel.org/doc/Documentation/filesystems/proc.txt">proc.txt</ulink> for | |
647 | details.</para></listitem> | |
648 | </varlistentry> | |
649 | ||
650 | <varlistentry> | |
651 | <term><varname>TimerSlackNSec=</varname></term> | |
652 | <listitem><para>Sets the timer slack in nanoseconds for the executed processes. The timer slack controls the | |
653 | accuracy of wake-ups triggered by timers. See | |
654 | <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry> for more | |
655 | information. Note that in contrast to most other time span definitions this parameter takes an integer value in | |
656 | nano-seconds if no unit is specified. The usual time units are understood too.</para></listitem> | |
657 | </varlistentry> | |
658 | ||
659 | <varlistentry> | |
660 | <term><varname>Personality=</varname></term> | |
661 | ||
662 | <listitem><para>Controls which kernel architecture <citerefentry | |
663 | project='man-pages'><refentrytitle>uname</refentrytitle><manvolnum>2</manvolnum></citerefentry> shall report, | |
664 | when invoked by unit processes. Takes one of the architecture identifiers <constant>x86</constant>, | |
665 | <constant>x86-64</constant>, <constant>ppc</constant>, <constant>ppc-le</constant>, <constant>ppc64</constant>, | |
666 | <constant>ppc64-le</constant>, <constant>s390</constant> or <constant>s390x</constant>. Which personality | |
667 | architectures are supported depends on the system architecture. Usually the 64bit versions of the various | |
668 | system architectures support their immediate 32bit personality architecture counterpart, but no others. For | |
669 | example, <constant>x86-64</constant> systems support the <constant>x86-64</constant> and | |
670 | <constant>x86</constant> personalities but no others. The personality feature is useful when running 32-bit | |
671 | services on a 64-bit host system. If not specified, the personality is left unmodified and thus reflects the | |
672 | personality of the host system's kernel.</para></listitem> | |
673 | </varlistentry> | |
674 | ||
675 | <varlistentry> | |
676 | <term><varname>IgnoreSIGPIPE=</varname></term> | |
677 | ||
678 | <listitem><para>Takes a boolean argument. If true, causes <constant>SIGPIPE</constant> to be ignored in the | |
679 | executed process. Defaults to true because <constant>SIGPIPE</constant> generally is useful only in shell | |
680 | pipelines.</para></listitem> | |
681 | </varlistentry> | |
682 | ||
683 | </variablelist> | |
684 | </refsect1> | |
685 | ||
686 | <refsect1> | |
687 | <title>Scheduling</title> | |
688 | ||
689 | <variablelist> | |
690 | ||
691 | <varlistentry> | |
692 | <term><varname>Nice=</varname></term> | |
693 | ||
694 | <listitem><para>Sets the default nice level (scheduling priority) for executed processes. Takes an integer | |
695 | between -20 (highest priority) and 19 (lowest priority). See | |
696 | <citerefentry><refentrytitle>setpriority</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
697 | details.</para></listitem> | |
698 | </varlistentry> | |
699 | ||
700 | <varlistentry> | |
701 | <term><varname>CPUSchedulingPolicy=</varname></term> | |
702 | ||
703 | <listitem><para>Sets the CPU scheduling policy for executed processes. Takes one of <option>other</option>, | |
704 | <option>batch</option>, <option>idle</option>, <option>fifo</option> or <option>rr</option>. See | |
705 | <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
706 | details.</para></listitem> | |
707 | </varlistentry> | |
708 | ||
709 | <varlistentry> | |
710 | <term><varname>CPUSchedulingPriority=</varname></term> | |
711 | ||
712 | <listitem><para>Sets the CPU scheduling priority for executed processes. The available priority range depends | |
713 | on the selected CPU scheduling policy (see above). For real-time scheduling policies an integer between 1 | |
714 | (lowest priority) and 99 (highest priority) can be used. See | |
715 | <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
716 | details. </para></listitem> | |
717 | </varlistentry> | |
718 | ||
719 | <varlistentry> | |
720 | <term><varname>CPUSchedulingResetOnFork=</varname></term> | |
721 | ||
722 | <listitem><para>Takes a boolean argument. If true, elevated CPU scheduling priorities and policies will be | |
723 | reset when the executed processes fork, and can hence not leak into child processes. See | |
724 | <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
725 | details. Defaults to false.</para></listitem> | |
726 | </varlistentry> | |
727 | ||
728 | <varlistentry> | |
729 | <term><varname>CPUAffinity=</varname></term> | |
730 | ||
731 | <listitem><para>Controls the CPU affinity of the executed processes. Takes a list of CPU indices or ranges | |
732 | separated by either whitespace or commas. CPU ranges are specified by the lower and upper CPU indices separated | |
733 | by a dash. This option may be specified more than once, in which case the specified CPU affinity masks are | |
734 | merged. If the empty string is assigned, the mask is reset, all assignments prior to this will have no | |
735 | effect. See | |
736 | <citerefentry><refentrytitle>sched_setaffinity</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
737 | details.</para></listitem> | |
738 | </varlistentry> | |
739 | ||
740 | <varlistentry> | |
741 | <term><varname>IOSchedulingClass=</varname></term> | |
742 | ||
743 | <listitem><para>Sets the I/O scheduling class for executed processes. Takes an integer between 0 and 3 or one | |
744 | of the strings <option>none</option>, <option>realtime</option>, <option>best-effort</option> or | |
745 | <option>idle</option>. See | |
746 | <citerefentry><refentrytitle>ioprio_set</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
747 | details.</para></listitem> | |
748 | </varlistentry> | |
749 | ||
750 | <varlistentry> | |
751 | <term><varname>IOSchedulingPriority=</varname></term> | |
752 | ||
753 | <listitem><para>Sets the I/O scheduling priority for executed processes. Takes an integer between 0 (highest | |
754 | priority) and 7 (lowest priority). The available priorities depend on the selected I/O scheduling class (see | |
755 | above). See <citerefentry><refentrytitle>ioprio_set</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
756 | details.</para></listitem> | |
757 | </varlistentry> | |
758 | ||
759 | </variablelist> | |
760 | </refsect1> | |
761 | ||
762 | ||
763 | <refsect1> | |
764 | <title>Sandboxing</title> | |
765 | ||
766 | <variablelist> | |
767 | ||
768 | <varlistentry> | |
769 | <term><varname>ProtectSystem=</varname></term> | |
770 | ||
771 | <listitem><para>Takes a boolean argument or the special values <literal>full</literal> or | |
772 | <literal>strict</literal>. If true, mounts the <filename>/usr</filename> and <filename>/boot</filename> | |
773 | directories read-only for processes invoked by this unit. If set to <literal>full</literal>, the | |
774 | <filename>/etc</filename> directory is mounted read-only, too. If set to <literal>strict</literal> the entire | |
775 | file system hierarchy is mounted read-only, except for the API file system subtrees <filename>/dev</filename>, | |
776 | <filename>/proc</filename> and <filename>/sys</filename> (protect these directories using | |
777 | <varname>PrivateDevices=</varname>, <varname>ProtectKernelTunables=</varname>, | |
778 | <varname>ProtectControlGroups=</varname>). This setting ensures that any modification of the vendor-supplied | |
779 | operating system (and optionally its configuration, and local mounts) is prohibited for the service. It is | |
780 | recommended to enable this setting for all long-running services, unless they are involved with system updates | |
781 | or need to modify the operating system in other ways. If this option is used, | |
782 | <varname>ReadWritePaths=</varname> may be used to exclude specific directories from being made read-only. This | |
783 | setting is implied if <varname>DynamicUser=</varname> is set. For this setting the same restrictions regarding | |
784 | mount propagation and privileges apply as for <varname>ReadOnlyPaths=</varname> and related calls, see | |
785 | below. Defaults to off.</para></listitem> | |
786 | </varlistentry> | |
787 | ||
788 | <varlistentry> | |
789 | <term><varname>ProtectHome=</varname></term> | |
790 | ||
791 | <listitem><para>Takes a boolean argument or <literal>read-only</literal>. If true, the directories | |
792 | <filename>/home</filename>, <filename>/root</filename> and <filename>/run/user</filename> are made inaccessible | |
793 | and empty for processes invoked by this unit. If set to <literal>read-only</literal>, the three directories are | |
794 | made read-only instead. It is recommended to enable this setting for all long-running services (in particular | |
795 | network-facing ones), to ensure they cannot get access to private user data, unless the services actually | |
796 | require access to the user's private data. This setting is implied if <varname>DynamicUser=</varname> is | |
797 | set. For this setting the same restrictions regarding mount propagation and privileges apply as for | |
798 | <varname>ReadOnlyPaths=</varname> and related calls, see below.</para></listitem> | |
799 | </varlistentry> | |
800 | ||
801 | <varlistentry> | |
802 | <term><varname>RuntimeDirectory=</varname></term> | |
803 | <term><varname>StateDirectory=</varname></term> | |
804 | <term><varname>CacheDirectory=</varname></term> | |
805 | <term><varname>LogsDirectory=</varname></term> | |
806 | <term><varname>ConfigurationDirectory=</varname></term> | |
807 | ||
808 | <listitem><para>These options take a whitespace-separated list of directory names. The specified directory | |
809 | names must be relative, and may not include <literal>.</literal> or <literal>..</literal>. If set, one or more | |
810 | directories by the specified names will be created (including their parents) below <filename>/run</filename> | |
811 | (or <varname>$XDG_RUNTIME_DIR</varname> for user services), <filename>/var/lib</filename> (or | |
812 | <varname>$XDG_CONFIG_HOME</varname> for user services), <filename>/var/cache</filename> (or | |
813 | <varname>$XDG_CACHE_HOME</varname> for user services), <filename>/var/log</filename> (or | |
814 | <varname>$XDG_CONFIG_HOME</varname><filename>/log</filename> for user services), or <filename>/etc</filename> | |
815 | (or <varname>$XDG_CONFIG_HOME</varname> for user services), respectively, when the unit is started.</para> | |
816 | ||
817 | <para>In case of <varname>RuntimeDirectory=</varname> the lowest subdirectories are removed when the unit is | |
818 | stopped. It is possible to preserve the specified directories in this case if | |
819 | <varname>RuntimeDirectoryPreserve=</varname> is configured to <option>restart</option> or <option>yes</option> | |
820 | (see below). The directories specified with <varname>StateDirectory=</varname>, | |
821 | <varname>CacheDirectory=</varname>, <varname>LogsDirectory=</varname>, | |
822 | <varname>ConfigurationDirectory=</varname> are not removed when the unit is stopped.</para> | |
823 | ||
824 | <para>Except in case of <varname>ConfigurationDirectory=</varname>, the innermost specified directories will be | |
825 | owned by the user and group specified in <varname>User=</varname> and <varname>Group=</varname>. If the | |
826 | specified directories already exist and their owning user or group do not match the configured ones, all files | |
827 | and directories below the specified directories as well as the directories themselves will have their file | |
828 | ownership recursively changed to match what is configured. As an optimization, if the specified directories are | |
829 | already owned by the right user and group, files and directories below of them are left as-is, even if they do | |
830 | not match what is requested. The innermost specified directories will have their access mode adjusted to the | |
831 | what is specified in <varname>RuntimeDirectoryMode=</varname>, <varname>StateDirectoryMode=</varname>, | |
832 | <varname>CacheDirectoryMode=</varname>, <varname>LogsDirectoryMode=</varname> and | |
833 | <varname>ConfigurationDirectoryMode=</varname>.</para> | |
5aaeeffb | 834 | |
b8afec21 LP |
835 | <para>These options imply <varname>BindPaths=</varname> for the specified paths. When combined with |
836 | <varname>RootDirectory=</varname> or <varname>RootImage=</varname> these paths always reside on the host and | |
837 | are mounted from there into the unit's file system namespace.</para> | |
798d3a52 | 838 | |
b8afec21 LP |
839 | <para>If <varname>DynamicUser=</varname> is used in conjunction with <varname>StateDirectory=</varname>, |
840 | <varname>CacheDirectory=</varname> and <varname>LogsDirectory=</varname> is slightly altered: the directories | |
841 | are created below <filename>/var/lib/private</filename>, <filename>/var/cache/private</filename> and | |
842 | <filename>/var/log/private</filename>, respectively, which are host directories made inaccessible to | |
843 | unprivileged users, which ensures that access to these directories cannot be gained through dynamic user ID | |
844 | recycling. Symbolic links are created to hide this difference in behaviour. Both from perspective of the host | |
845 | and from inside the unit, the relevant directories hence always appear directly below | |
846 | <filename>/var/lib</filename>, <filename>/var/cache</filename> and <filename>/var/log</filename>.</para> | |
798d3a52 | 847 | |
b8afec21 LP |
848 | <para>Use <varname>RuntimeDirectory=</varname> to manage one or more runtime directories for the unit and bind |
849 | their lifetime to the daemon runtime. This is particularly useful for unprivileged daemons that cannot create | |
850 | runtime directories in <filename>/run</filename> due to lack of privileges, and to make sure the runtime | |
851 | directory is cleaned up automatically after use. For runtime directories that require more complex or different | |
852 | configuration or lifetime guarantees, please consider using | |
853 | <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
de7070b4 | 854 | |
b8afec21 LP |
855 | <para>Example: if a system service unit has the following, |
856 | <programlisting>RuntimeDirectory=foo/bar baz</programlisting> | |
857 | the service manager creates <filename>/run/foo</filename> (if it does not exist), | |
858 | <filename>/run/foo/bar</filename>, and <filename>/run/baz</filename>. The directories | |
859 | <filename>/run/foo/bar</filename> and <filename>/run/baz</filename> except <filename>/run/foo</filename> are | |
860 | owned by the user and group specified in <varname>User=</varname> and <varname>Group=</varname>, and removed | |
861 | when the service is stopped.</para></listitem> | |
798d3a52 ZJS |
862 | </varlistentry> |
863 | ||
ece87975 | 864 | <varlistentry> |
b8afec21 LP |
865 | <term><varname>RuntimeDirectoryMode=</varname></term> |
866 | <term><varname>StateDirectoryMode=</varname></term> | |
867 | <term><varname>CacheDirectoryMode=</varname></term> | |
868 | <term><varname>LogsDirectoryMode=</varname></term> | |
869 | <term><varname>ConfigurationDirectoryMode=</varname></term> | |
ece87975 | 870 | |
b8afec21 LP |
871 | <listitem><para>Specifies the access mode of the directories specified in <varname>RuntimeDirectory=</varname>, |
872 | <varname>StateDirectory=</varname>, <varname>CacheDirectory=</varname>, <varname>LogsDirectory=</varname>, or | |
873 | <varname>ConfigurationDirectory=</varname>, respectively, as an octal number. Defaults to | |
874 | <constant>0755</constant>. See "Permissions" in <citerefentry | |
875 | project='man-pages'><refentrytitle>path_resolution</refentrytitle><manvolnum>7</manvolnum></citerefentry> for a | |
876 | discussion of the meaning of permission bits.</para></listitem> | |
ece87975 IP |
877 | </varlistentry> |
878 | ||
798d3a52 | 879 | <varlistentry> |
b8afec21 LP |
880 | <term><varname>RuntimeDirectoryPreserve=</varname></term> |
881 | ||
882 | <listitem><para>Takes a boolean argument or <option>restart</option>. If set to <option>no</option> (the | |
883 | default), the directories specified in <varname>RuntimeDirectory=</varname> are always removed when the service | |
884 | stops. If set to <option>restart</option> the directories are preserved when the service is both automatically | |
885 | and manually restarted. Here, the automatic restart means the operation specified in | |
886 | <varname>Restart=</varname>, and manual restart means the one triggered by <command>systemctl restart | |
887 | foo.service</command>. If set to <option>yes</option>, then the directories are not removed when the service is | |
888 | stopped. Note that since the runtime directory <filename>/run</filename> is a mount point of | |
889 | <literal>tmpfs</literal>, then for system services the directories specified in | |
890 | <varname>RuntimeDirectory=</varname> are removed when the system is rebooted.</para></listitem> | |
798d3a52 ZJS |
891 | </varlistentry> |
892 | ||
798d3a52 | 893 | <varlistentry> |
2a624c36 AP |
894 | <term><varname>ReadWritePaths=</varname></term> |
895 | <term><varname>ReadOnlyPaths=</varname></term> | |
896 | <term><varname>InaccessiblePaths=</varname></term> | |
798d3a52 | 897 | |
effbd6d2 LP |
898 | <listitem><para>Sets up a new file system namespace for executed processes. These options may be used to limit |
899 | access a process might have to the file system hierarchy. Each setting takes a space-separated list of paths | |
900 | relative to the host's root directory (i.e. the system running the service manager). Note that if paths | |
901 | contain symlinks, they are resolved relative to the root directory set with | |
915e6d16 | 902 | <varname>RootDirectory=</varname>/<varname>RootImage=</varname>.</para> |
effbd6d2 LP |
903 | |
904 | <para>Paths listed in <varname>ReadWritePaths=</varname> are accessible from within the namespace with the same | |
905 | access modes as from outside of it. Paths listed in <varname>ReadOnlyPaths=</varname> are accessible for | |
906 | reading only, writing will be refused even if the usual file access controls would permit this. Nest | |
907 | <varname>ReadWritePaths=</varname> inside of <varname>ReadOnlyPaths=</varname> in order to provide writable | |
908 | subdirectories within read-only directories. Use <varname>ReadWritePaths=</varname> in order to whitelist | |
909 | specific paths for write access if <varname>ProtectSystem=strict</varname> is used. Paths listed in | |
910 | <varname>InaccessiblePaths=</varname> will be made inaccessible for processes inside the namespace (along with | |
911 | everything below them in the file system hierarchy).</para> | |
912 | ||
913 | <para>Note that restricting access with these options does not extend to submounts of a directory that are | |
914 | created later on. Non-directory paths may be specified as well. These options may be specified more than once, | |
915 | in which case all paths listed will have limited access from within the namespace. If the empty string is | |
916 | assigned to this option, the specific list is reset, and all prior assignments have no effect.</para> | |
917 | ||
e778185b | 918 | <para>Paths in <varname>ReadWritePaths=</varname>, <varname>ReadOnlyPaths=</varname> and |
5327c910 LP |
919 | <varname>InaccessiblePaths=</varname> may be prefixed with <literal>-</literal>, in which case they will be |
920 | ignored when they do not exist. If prefixed with <literal>+</literal> the paths are taken relative to the root | |
915e6d16 LP |
921 | directory of the unit, as configured with <varname>RootDirectory=</varname>/<varname>RootImage=</varname>, |
922 | instead of relative to the root directory of the host (see above). When combining <literal>-</literal> and | |
923 | <literal>+</literal> on the same path make sure to specify <literal>-</literal> first, and <literal>+</literal> | |
924 | second.</para> | |
5327c910 LP |
925 | |
926 | <para>Note that using this setting will disconnect propagation of mounts from the service to the host | |
927 | (propagation in the opposite direction continues to work). This means that this setting may not be used for | |
928 | services which shall be able to install mount points in the main mount namespace. Note that the effect of these | |
929 | settings may be undone by privileged processes. In order to set up an effective sandboxed environment for a | |
930 | unit it is thus recommended to combine these settings with either | |
931 | <varname>CapabilityBoundingSet=~CAP_SYS_ADMIN</varname> or | |
932 | <varname>SystemCallFilter=~@mount</varname>.</para></listitem> | |
798d3a52 ZJS |
933 | </varlistentry> |
934 | ||
c10b460b YW |
935 | <varlistentry> |
936 | <term><varname>TemporaryFileSystem=</varname></term> | |
937 | ||
938 | <listitem><para>Takes a space-separated list of mount points for temporary file systems (tmpfs). If set, a new file | |
939 | system namespace is set up for executed processes, and a temporary file system is mounted on each mount point. | |
940 | This option may be specified more than once, in which case temporary file systems are mounted on all listed mount | |
941 | points. If the empty string is assigned to this option, the list is reset, and all prior assignments have no effect. | |
942 | Each mount point may optionally be suffixed with a colon (<literal>:</literal>) and mount options such as | |
943 | <literal>size=10%</literal> or <literal>ro</literal>. By default, each temporary file system is mounted | |
944 | with <literal>nodev,strictatime,mode=0755</literal>. These can be disabled by explicitly specifying the corresponding | |
945 | mount options, e.g., <literal>dev</literal> or <literal>nostrictatime</literal>.</para> | |
946 | ||
947 | <para>This is useful to hide files or directories not relevant to the processes invoked by the unit, while necessary | |
948 | files or directories can be still accessed by combining with <varname>BindPaths=</varname> or | |
949 | <varname>BindReadOnlyPaths=</varname>. See the example below.</para> | |
950 | ||
951 | <para>Example: if a unit has the following, | |
952 | <programlisting>TemporaryFileSystem=/var:ro | |
953 | BindReadOnlyPaths=/var/lib/systemd</programlisting> | |
954 | then the invoked processes by the unit cannot see any files or directories under <filename>/var</filename> except for | |
955 | <filename>/var/lib/systemd</filename> or its contents.</para></listitem> | |
956 | </varlistentry> | |
957 | ||
798d3a52 ZJS |
958 | <varlistentry> |
959 | <term><varname>PrivateTmp=</varname></term> | |
960 | ||
00d9ef85 LP |
961 | <listitem><para>Takes a boolean argument. If true, sets up a new file system namespace for the executed |
962 | processes and mounts private <filename>/tmp</filename> and <filename>/var/tmp</filename> directories inside it | |
963 | that is not shared by processes outside of the namespace. This is useful to secure access to temporary files of | |
964 | the process, but makes sharing between processes via <filename>/tmp</filename> or <filename>/var/tmp</filename> | |
965 | impossible. If this is enabled, all temporary files created by a service in these directories will be removed | |
966 | after the service is stopped. Defaults to false. It is possible to run two or more units within the same | |
967 | private <filename>/tmp</filename> and <filename>/var/tmp</filename> namespace by using the | |
798d3a52 | 968 | <varname>JoinsNamespaceOf=</varname> directive, see |
00d9ef85 | 969 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for |
effbd6d2 LP |
970 | details. This setting is implied if <varname>DynamicUser=</varname> is set. For this setting the same |
971 | restrictions regarding mount propagation and privileges apply as for <varname>ReadOnlyPaths=</varname> and | |
d71f0505 LP |
972 | related calls, see above. Enabling this setting has the side effect of adding <varname>Requires=</varname> and |
973 | <varname>After=</varname> dependencies on all mount units necessary to access <filename>/tmp</filename> and | |
974 | <filename>/var/tmp</filename>. Moreover an implicitly <varname>After=</varname> ordering on | |
975 | <citerefentry><refentrytitle>systemd-tmpfiles-setup.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
b0238568 ZJS |
976 | is added.</para> |
977 | ||
b8afec21 LP |
978 | <para>Note that the implementation of this setting might be impossible (for example if mount namespaces are not |
979 | available), and the unit should be written in a way that does not solely rely on this setting for | |
b0238568 | 980 | security.</para></listitem> |
798d3a52 ZJS |
981 | </varlistentry> |
982 | ||
983 | <varlistentry> | |
984 | <term><varname>PrivateDevices=</varname></term> | |
985 | ||
b0238568 ZJS |
986 | <listitem><para>Takes a boolean argument. If true, sets up a new <filename>/dev</filename> mount for the |
987 | executed processes and only adds API pseudo devices such as <filename>/dev/null</filename>, | |
b8afec21 LP |
988 | <filename>/dev/zero</filename> or <filename>/dev/random</filename> (as well as the pseudo TTY subsystem) to it, |
989 | but no physical devices such as <filename>/dev/sda</filename>, system memory <filename>/dev/mem</filename>, | |
990 | system ports <filename>/dev/port</filename> and others. This is useful to securely turn off physical device | |
991 | access by the executed process. Defaults to false. Enabling this option will install a system call filter to | |
992 | block low-level I/O system calls that are grouped in the <varname>@raw-io</varname> set, will also remove | |
993 | <constant>CAP_MKNOD</constant> and <constant>CAP_SYS_RAWIO</constant> from the capability bounding set for the | |
994 | unit (see above), and set <varname>DevicePolicy=closed</varname> (see | |
798d3a52 | 995 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
effbd6d2 LP |
996 | for details). Note that using this setting will disconnect propagation of mounts from the service to the host |
997 | (propagation in the opposite direction continues to work). This means that this setting may not be used for | |
b8afec21 LP |
998 | services which shall be able to install mount points in the main mount namespace. The new |
999 | <filename>/dev</filename> will be mounted read-only and 'noexec'. The latter may break old programs which try | |
1000 | to set up executable memory by using | |
1001 | <citerefentry><refentrytitle>mmap</refentrytitle><manvolnum>2</manvolnum></citerefentry> of | |
1002 | <filename>/dev/zero</filename> instead of using <constant>MAP_ANON</constant>. For this setting the same | |
1003 | restrictions regarding mount propagation and privileges apply as for <varname>ReadOnlyPaths=</varname> and | |
1004 | related calls, see above. If turned on and if running in user mode, or in system mode, but without the | |
1005 | <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting <varname>User=</varname>), | |
1006 | <varname>NoNewPrivileges=yes</varname> is implied.</para> | |
b0238568 | 1007 | |
b8afec21 LP |
1008 | <para>Note that the implementation of this setting might be impossible (for example if mount namespaces are not |
1009 | available), and the unit should be written in a way that does not solely rely on this setting for | |
b0238568 | 1010 | security.</para></listitem> |
798d3a52 ZJS |
1011 | </varlistentry> |
1012 | ||
1013 | <varlistentry> | |
1014 | <term><varname>PrivateNetwork=</varname></term> | |
1015 | ||
b8afec21 LP |
1016 | <listitem><para>Takes a boolean argument. If true, sets up a new network namespace for the executed processes |
1017 | and configures only the loopback network device <literal>lo</literal> inside it. No other network devices will | |
1018 | be available to the executed process. This is useful to turn off network access by the executed process. | |
1019 | Defaults to false. It is possible to run two or more units within the same private network namespace by using | |
1020 | the <varname>JoinsNamespaceOf=</varname> directive, see | |
1021 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for | |
1022 | details. Note that this option will disconnect all socket families from the host, this includes AF_NETLINK and | |
1023 | AF_UNIX. The latter has the effect that AF_UNIX sockets in the abstract socket namespace will become | |
1024 | unavailable to the processes (however, those located in the file system will continue to be accessible).</para> | |
1025 | ||
1026 | <para>Note that the implementation of this setting might be impossible (for example if network namespaces are | |
1027 | not available), and the unit should be written in a way that does not solely rely on this setting for | |
b0238568 | 1028 | security.</para></listitem> |
798d3a52 ZJS |
1029 | </varlistentry> |
1030 | ||
1031 | <varlistentry> | |
d251207d LP |
1032 | <term><varname>PrivateUsers=</varname></term> |
1033 | ||
1034 | <listitem><para>Takes a boolean argument. If true, sets up a new user namespace for the executed processes and | |
1035 | configures a minimal user and group mapping, that maps the <literal>root</literal> user and group as well as | |
1036 | the unit's own user and group to themselves and everything else to the <literal>nobody</literal> user and | |
1037 | group. This is useful to securely detach the user and group databases used by the unit from the rest of the | |
1038 | system, and thus to create an effective sandbox environment. All files, directories, processes, IPC objects and | |
2dd67817 | 1039 | other resources owned by users/groups not equaling <literal>root</literal> or the unit's own will stay visible |
d251207d LP |
1040 | from within the unit but appear owned by the <literal>nobody</literal> user and group. If this mode is enabled, |
1041 | all unit processes are run without privileges in the host user namespace (regardless if the unit's own | |
1042 | user/group is <literal>root</literal> or not). Specifically this means that the process will have zero process | |
1043 | capabilities on the host's user namespace, but full capabilities within the service's user namespace. Settings | |
1044 | such as <varname>CapabilityBoundingSet=</varname> will affect only the latter, and there's no way to acquire | |
1045 | additional capabilities in the host's user namespace. Defaults to off.</para> | |
1046 | ||
915e6d16 LP |
1047 | <para>This setting is particularly useful in conjunction with |
1048 | <varname>RootDirectory=</varname>/<varname>RootImage=</varname>, as the need to synchronize the user and group | |
1049 | databases in the root directory and on the host is reduced, as the only users and groups who need to be matched | |
b0238568 ZJS |
1050 | are <literal>root</literal>, <literal>nobody</literal> and the unit's own user and group.</para> |
1051 | ||
b8afec21 LP |
1052 | <para>Note that the implementation of this setting might be impossible (for example if user namespaces are not |
1053 | available), and the unit should be written in a way that does not solely rely on this setting for | |
b0238568 | 1054 | security.</para></listitem> |
d251207d LP |
1055 | </varlistentry> |
1056 | ||
59eeb84b LP |
1057 | <varlistentry> |
1058 | <term><varname>ProtectKernelTunables=</varname></term> | |
1059 | ||
1060 | <listitem><para>Takes a boolean argument. If true, kernel variables accessible through | |
49accde7 DH |
1061 | <filename>/proc/sys</filename>, <filename>/sys</filename>, <filename>/proc/sysrq-trigger</filename>, |
1062 | <filename>/proc/latency_stats</filename>, <filename>/proc/acpi</filename>, | |
1063 | <filename>/proc/timer_stats</filename>, <filename>/proc/fs</filename> and <filename>/proc/irq</filename> will | |
525872bf LP |
1064 | be made read-only to all processes of the unit. Usually, tunable kernel variables should be initialized only at |
1065 | boot-time, for example with the | |
1066 | <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry> mechanism. Few | |
1067 | services need to write to these at runtime; it is hence recommended to turn this on for most services. For this | |
1068 | setting the same restrictions regarding mount propagation and privileges apply as for | |
1069 | <varname>ReadOnlyPaths=</varname> and related calls, see above. Defaults to off. If turned on and if running | |
1070 | in user mode, or in system mode, but without the <constant>CAP_SYS_ADMIN</constant> capability (e.g. services | |
1071 | for which <varname>User=</varname> is set), <varname>NoNewPrivileges=yes</varname> is implied. Note that this | |
1072 | option does not prevent indirect changes to kernel tunables effected by IPC calls to other processes. However, | |
1073 | <varname>InaccessiblePaths=</varname> may be used to make relevant IPC file system objects inaccessible. If | |
1074 | <varname>ProtectKernelTunables=</varname> is set, <varname>MountAPIVFS=yes</varname> is | |
1075 | implied.</para></listitem> | |
59eeb84b LP |
1076 | </varlistentry> |
1077 | ||
85265556 DH |
1078 | <varlistentry> |
1079 | <term><varname>ProtectKernelModules=</varname></term> | |
1080 | ||
b8afec21 LP |
1081 | <listitem><para>Takes a boolean argument. If true, explicit module loading will be denied. This allows to turn |
1082 | off module load and unload operations on modular kernels. It is recommended to turn this on for most services | |
bf2d3d7c | 1083 | that do not need special file systems or extra kernel modules to work. Defaults to off. Enabling this option |
b8afec21 LP |
1084 | removes <constant>CAP_SYS_MODULE</constant> from the capability bounding set for the unit, and installs a |
1085 | system call filter to block module system calls, also <filename>/usr/lib/modules</filename> is made | |
1086 | inaccessible. For this setting the same restrictions regarding mount propagation and privileges apply as for | |
1087 | <varname>ReadOnlyPaths=</varname> and related calls, see above. Note that limited automatic module loading due | |
1088 | to user configuration or kernel mapping tables might still happen as side effect of requested user operations, | |
85265556 DH |
1089 | both privileged and unprivileged. To disable module auto-load feature please see |
1090 | <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
1091 | <constant>kernel.modules_disabled</constant> mechanism and | |
b8afec21 LP |
1092 | <filename>/proc/sys/kernel/modules_disabled</filename> documentation. If turned on and if running in user |
1093 | mode, or in system mode, but without the <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting | |
1094 | <varname>User=</varname>), <varname>NoNewPrivileges=yes</varname> is implied.</para></listitem> | |
85265556 DH |
1095 | </varlistentry> |
1096 | ||
59eeb84b LP |
1097 | <varlistentry> |
1098 | <term><varname>ProtectControlGroups=</varname></term> | |
1099 | ||
effbd6d2 LP |
1100 | <listitem><para>Takes a boolean argument. If true, the Linux Control Groups (<citerefentry |
1101 | project='man-pages'><refentrytitle>cgroups</refentrytitle><manvolnum>7</manvolnum></citerefentry>) hierarchies | |
1102 | accessible through <filename>/sys/fs/cgroup</filename> will be made read-only to all processes of the | |
1103 | unit. Except for container managers no services should require write access to the control groups hierarchies; | |
1104 | it is hence recommended to turn this on for most services. For this setting the same restrictions regarding | |
1105 | mount propagation and privileges apply as for <varname>ReadOnlyPaths=</varname> and related calls, see | |
b8afec21 LP |
1106 | above. Defaults to off. If <varname>ProtectControlGroups=</varname> is set, <varname>MountAPIVFS=yes</varname> |
1107 | is implied.</para></listitem> | |
798d3a52 ZJS |
1108 | </varlistentry> |
1109 | ||
1110 | <varlistentry> | |
b8afec21 | 1111 | <term><varname>RestrictAddressFamilies=</varname></term> |
798d3a52 | 1112 | |
b8afec21 LP |
1113 | <listitem><para>Restricts the set of socket address families accessible to the processes of this unit. Takes a |
1114 | space-separated list of address family names to whitelist, such as <constant>AF_UNIX</constant>, | |
1115 | <constant>AF_INET</constant> or <constant>AF_INET6</constant>. When prefixed with <constant>~</constant> the | |
1116 | listed address families will be applied as blacklist, otherwise as whitelist. Note that this restricts access | |
1117 | to the <citerefentry | |
1118 | project='man-pages'><refentrytitle>socket</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call | |
1119 | only. Sockets passed into the process by other means (for example, by using socket activation with socket | |
1120 | units, see <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>) | |
1121 | are unaffected. Also, sockets created with <function>socketpair()</function> (which creates connected AF_UNIX | |
1122 | sockets only) are unaffected. Note that this option has no effect on 32-bit x86, s390, s390x, mips, mips-le, | |
1123 | ppc, ppc-le, pcc64, ppc64-le and is ignored (but works correctly on other ABIs, including x86-64). Note that on | |
1124 | systems supporting multiple ABIs (such as x86/x86-64) it is recommended to turn off alternative ABIs for | |
1125 | services, so that they cannot be used to circumvent the restrictions of this option. Specifically, it is | |
1126 | recommended to combine this option with <varname>SystemCallArchitectures=native</varname> or similar. If | |
1127 | running in user mode, or in system mode, but without the <constant>CAP_SYS_ADMIN</constant> capability | |
1128 | (e.g. setting <varname>User=nobody</varname>), <varname>NoNewPrivileges=yes</varname> is implied. By default, | |
1129 | no restrictions apply, all address families are accessible to processes. If assigned the empty string, any | |
1130 | previous address familiy restriction changes are undone. This setting does not affect commands prefixed with | |
1131 | <literal>+</literal>.</para> | |
1132 | ||
1133 | <para>Use this option to limit exposure of processes to remote access, in particular via exotic and sensitive | |
1134 | network protocols, such as <constant>AF_PACKET</constant>. Note that in most cases, the local | |
1135 | <constant>AF_UNIX</constant> address family should be included in the configured whitelist as it is frequently | |
1136 | used for local communication, including for | |
1137 | <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
1138 | logging.</para></listitem> | |
798d3a52 ZJS |
1139 | </varlistentry> |
1140 | ||
1141 | <varlistentry> | |
b8afec21 | 1142 | <term><varname>RestrictNamespaces=</varname></term> |
798d3a52 | 1143 | |
b8afec21 LP |
1144 | <listitem><para>Restricts access to Linux namespace functionality for the processes of this unit. For details |
1145 | about Linux namespaces, see <citerefentry | |
1146 | project='man-pages'><refentrytitle>namespaces</refentrytitle><manvolnum>7</manvolnum></citerefentry>. Either | |
1147 | takes a boolean argument, or a space-separated list of namespace type identifiers. If false (the default), no | |
1148 | restrictions on namespace creation and switching are made. If true, access to any kind of namespacing is | |
1149 | prohibited. Otherwise, a space-separated list of namespace type identifiers must be specified, consisting of | |
1150 | any combination of: <constant>cgroup</constant>, <constant>ipc</constant>, <constant>net</constant>, | |
1151 | <constant>mnt</constant>, <constant>pid</constant>, <constant>user</constant> and <constant>uts</constant>. Any | |
1152 | namespace type listed is made accessible to the unit's processes, access to namespace types not listed is | |
1153 | prohibited (whitelisting). By prepending the list with a single tilde character (<literal>~</literal>) the | |
1154 | effect may be inverted: only the listed namespace types will be made inaccessible, all unlisted ones are | |
1155 | permitted (blacklisting). If the empty string is assigned, the default namespace restrictions are applied, | |
1156 | which is equivalent to false. Internally, this setting limits access to the | |
1157 | <citerefentry><refentrytitle>unshare</refentrytitle><manvolnum>2</manvolnum></citerefentry>, | |
1158 | <citerefentry><refentrytitle>clone</refentrytitle><manvolnum>2</manvolnum></citerefentry> and | |
1159 | <citerefentry><refentrytitle>setns</refentrytitle><manvolnum>2</manvolnum></citerefentry> system calls, taking | |
1160 | the specified flags parameters into account. Note that — if this option is used — in addition to restricting | |
1161 | creation and switching of the specified types of namespaces (or all of them, if true) access to the | |
1162 | <function>setns()</function> system call with a zero flags parameter is prohibited. This setting is only | |
1163 | supported on x86, x86-64, mips, mips-le, mips64, mips64-le, mips64-n32, mips64-le-n32, ppc64, ppc64-le, s390 | |
1164 | and s390x, and enforces no restrictions on other architectures. If running in user mode, or in system mode, but | |
1165 | without the <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting <varname>User=</varname>), | |
1166 | <varname>NoNewPrivileges=yes</varname> is implied. </para></listitem> | |
798d3a52 ZJS |
1167 | </varlistentry> |
1168 | ||
023a4f67 | 1169 | <varlistentry> |
b8afec21 | 1170 | <term><varname>LockPersonality=</varname></term> |
023a4f67 | 1171 | |
b8afec21 LP |
1172 | <listitem><para>Takes a boolean argument. If set, locks down the <citerefentry |
1173 | project='man-pages'><refentrytitle>personality</refentrytitle><manvolnum>2</manvolnum></citerefentry> system | |
1174 | call so that the kernel execution domain may not be changed from the default or the personality selected with | |
1175 | <varname>Personality=</varname> directive. This may be useful to improve security, because odd personality | |
1176 | emulations may be poorly tested and source of vulnerabilities. If running in user mode, or in system mode, but | |
1177 | without the <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting <varname>User=</varname>), | |
1178 | <varname>NoNewPrivileges=yes</varname> is implied.</para></listitem> | |
023a4f67 LP |
1179 | </varlistentry> |
1180 | ||
798d3a52 | 1181 | <varlistentry> |
b8afec21 | 1182 | <term><varname>MemoryDenyWriteExecute=</varname></term> |
798d3a52 | 1183 | |
b8afec21 LP |
1184 | <listitem><para>Takes a boolean argument. If set, attempts to create memory mappings that are writable and |
1185 | executable at the same time, or to change existing memory mappings to become executable, or mapping shared | |
1186 | memory segments as executable are prohibited. Specifically, a system call filter is added that rejects | |
1187 | <citerefentry><refentrytitle>mmap</refentrytitle><manvolnum>2</manvolnum></citerefentry> system calls with both | |
1188 | <constant>PROT_EXEC</constant> and <constant>PROT_WRITE</constant> set, | |
1189 | <citerefentry><refentrytitle>mprotect</refentrytitle><manvolnum>2</manvolnum></citerefentry> or | |
1190 | <citerefentry><refentrytitle>pkey_mprotect</refentrytitle><manvolnum>2</manvolnum></citerefentry> system calls | |
1191 | with <constant>PROT_EXEC</constant> set and | |
1192 | <citerefentry><refentrytitle>shmat</refentrytitle><manvolnum>2</manvolnum></citerefentry> system calls with | |
1193 | <constant>SHM_EXEC</constant> set. Note that this option is incompatible with programs and libraries that | |
1194 | generate program code dynamically at runtime, including JIT execution engines, executable stacks, and code | |
1195 | "trampoline" feature of various C compilers. This option improves service security, as it makes harder for | |
1196 | software exploits to change running code dynamically. Note that this feature is fully available on x86-64, and | |
1197 | partially on x86. Specifically, the <function>shmat()</function> protection is not available on x86. Note that | |
1198 | on systems supporting multiple ABIs (such as x86/x86-64) it is recommended to turn off alternative ABIs for | |
1199 | services, so that they cannot be used to circumvent the restrictions of this option. Specifically, it is | |
1200 | recommended to combine this option with <varname>SystemCallArchitectures=native</varname> or similar. If | |
1201 | running in user mode, or in system mode, but without the <constant>CAP_SYS_ADMIN</constant> capability | |
1202 | (e.g. setting <varname>User=</varname>), <varname>NoNewPrivileges=yes</varname> is implied.</para></listitem> | |
798d3a52 ZJS |
1203 | </varlistentry> |
1204 | ||
1205 | <varlistentry> | |
b8afec21 | 1206 | <term><varname>RestrictRealtime=</varname></term> |
798d3a52 | 1207 | |
b8afec21 LP |
1208 | <listitem><para>Takes a boolean argument. If set, any attempts to enable realtime scheduling in a process of |
1209 | the unit are refused. This restricts access to realtime task scheduling policies such as | |
1210 | <constant>SCHED_FIFO</constant>, <constant>SCHED_RR</constant> or <constant>SCHED_DEADLINE</constant>. See | |
1211 | <citerefentry project='man-pages'><refentrytitle>sched</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
1212 | for details about these scheduling policies. If running in user mode, or in system mode, but without the | |
1213 | <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting <varname>User=</varname>), | |
1214 | <varname>NoNewPrivileges=yes</varname> is implied. Realtime scheduling policies may be used to monopolize CPU | |
1215 | time for longer periods of time, and may hence be used to lock up or otherwise trigger Denial-of-Service | |
1216 | situations on the system. It is hence recommended to restrict access to realtime scheduling to the few programs | |
1217 | that actually require them. Defaults to off.</para></listitem> | |
798d3a52 ZJS |
1218 | </varlistentry> |
1219 | ||
1220 | <varlistentry> | |
b8afec21 | 1221 | <term><varname>RemoveIPC=</varname></term> |
798d3a52 | 1222 | |
b8afec21 LP |
1223 | <listitem><para>Takes a boolean parameter. If set, all System V and POSIX IPC objects owned by the user and |
1224 | group the processes of this unit are run as are removed when the unit is stopped. This setting only has an | |
1225 | effect if at least one of <varname>User=</varname>, <varname>Group=</varname> and | |
1226 | <varname>DynamicUser=</varname> are used. It has no effect on IPC objects owned by the root user. Specifically, | |
1227 | this removes System V semaphores, as well as System V and POSIX shared memory segments and message queues. If | |
1228 | multiple units use the same user or group the IPC objects are removed when the last of these units is | |
1229 | stopped. This setting is implied if <varname>DynamicUser=</varname> is set.</para></listitem> | |
798d3a52 ZJS |
1230 | </varlistentry> |
1231 | ||
1232 | <varlistentry> | |
b8afec21 | 1233 | <term><varname>MountFlags=</varname></term> |
798d3a52 | 1234 | |
b8afec21 LP |
1235 | <listitem><para>Takes a mount propagation flag: <option>shared</option>, <option>slave</option> or |
1236 | <option>private</option>, which control whether mounts in the file system namespace set up for this unit's | |
1237 | processes will receive or propagate mounts and unmounts. See <citerefentry | |
1238 | project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
1239 | details. Defaults to <option>shared</option>. Use <option>shared</option> to ensure that mounts and unmounts | |
1240 | are propagated from systemd's namespace to the service's namespace and vice versa. Use <option>slave</option> | |
1241 | to run processes so that none of their mounts and unmounts will propagate to the host. Use | |
1242 | <option>private</option> to also ensure that no mounts and unmounts from the host will propagate into the unit | |
1243 | processes' namespace. If this is set to <option>slave</option> or <option>private</option>, any mounts created | |
1244 | by spawned processes will be unmounted after the completion of the current command line of | |
1245 | <varname>ExecStartPre=</varname>, <varname>ExecStartPost=</varname>, <varname>ExecStart=</varname>, and | |
1246 | <varname>ExecStopPost=</varname>. Note that <option>slave</option> means that file systems mounted on the host | |
1247 | might stay mounted continuously in the unit's namespace, and thus keep the device busy. Note that the file | |
1248 | system namespace related options (<varname>PrivateTmp=</varname>, <varname>PrivateDevices=</varname>, | |
1249 | <varname>ProtectSystem=</varname>, <varname>ProtectHome=</varname>, <varname>ProtectKernelTunables=</varname>, | |
1250 | <varname>ProtectControlGroups=</varname>, <varname>ReadOnlyPaths=</varname>, | |
1251 | <varname>InaccessiblePaths=</varname>, <varname>ReadWritePaths=</varname>) require that mount and unmount | |
1252 | propagation from the unit's file system namespace is disabled, and hence downgrade <option>shared</option> to | |
1253 | <option>slave</option>. </para></listitem> | |
798d3a52 ZJS |
1254 | </varlistentry> |
1255 | ||
b8afec21 LP |
1256 | </variablelist> |
1257 | </refsect1> | |
a6fabe38 | 1258 | |
b8afec21 LP |
1259 | <refsect1> |
1260 | <title>System Call Filtering</title> | |
1261 | <variablelist> | |
798d3a52 ZJS |
1262 | |
1263 | <varlistentry> | |
1264 | <term><varname>SystemCallFilter=</varname></term> | |
1265 | ||
c79aff9a LP |
1266 | <listitem><para>Takes a space-separated list of system call names. If this setting is used, all system calls |
1267 | executed by the unit processes except for the listed ones will result in immediate process termination with the | |
1268 | <constant>SIGSYS</constant> signal (whitelisting). If the first character of the list is <literal>~</literal>, | |
1269 | the effect is inverted: only the listed system calls will result in immediate process termination | |
8cfa775f YW |
1270 | (blacklisting). Blacklisted system calls and system call groups may optionally be suffixed with a colon |
1271 | (<literal>:</literal>) and <literal>errno</literal> error number (between 0 and 4095) or errno name such as | |
1272 | <constant>EPERM</constant>, <constant>EACCES</constant> or <constant>EUCLEAN</constant>. This value will be | |
b8afec21 LP |
1273 | returned when a blacklisted system call is triggered, instead of terminating the processes immediately. This |
1274 | value takes precedence over the one given in <varname>SystemCallErrorNumber=</varname>. If running in user | |
1275 | mode, or in system mode, but without the <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting | |
1276 | <varname>User=nobody</varname>), <varname>NoNewPrivileges=yes</varname> is implied. This feature makes use of | |
1277 | the Secure Computing Mode 2 interfaces of the kernel ('seccomp filtering') and is useful for enforcing a | |
1278 | minimal sandboxing environment. Note that the <function>execve</function>, <function>exit</function>, | |
1279 | <function>exit_group</function>, <function>getrlimit</function>, <function>rt_sigreturn</function>, | |
1280 | <function>sigreturn</function> system calls and the system calls for querying time and sleeping are implicitly | |
1281 | whitelisted and do not need to be listed explicitly. This option may be specified more than once, in which case | |
1282 | the filter masks are merged. If the empty string is assigned, the filter is reset, all prior assignments will | |
1283 | have no effect. This does not affect commands prefixed with <literal>+</literal>.</para> | |
798d3a52 | 1284 | |
0b8fab97 LP |
1285 | <para>Note that on systems supporting multiple ABIs (such as x86/x86-64) it is recommended to turn off |
1286 | alternative ABIs for services, so that they cannot be used to circumvent the restrictions of this | |
1287 | option. Specifically, it is recommended to combine this option with | |
1288 | <varname>SystemCallArchitectures=native</varname> or similar.</para> | |
1289 | ||
2ca8dc15 LP |
1290 | <para>Note that strict system call filters may impact execution and error handling code paths of the service |
1291 | invocation. Specifically, access to the <function>execve</function> system call is required for the execution | |
1292 | of the service binary — if it is blocked service invocation will necessarily fail. Also, if execution of the | |
1293 | service binary fails for some reason (for example: missing service executable), the error handling logic might | |
1294 | require access to an additional set of system calls in order to process and log this failure correctly. It | |
1295 | might be necessary to temporarily disable system call filters in order to simplify debugging of such | |
1296 | failures.</para> | |
1297 | ||
b8afec21 LP |
1298 | <para>If you specify both types of this option (i.e. whitelisting and blacklisting), the first encountered |
1299 | will take precedence and will dictate the default action (termination or approval of a system call). Then the | |
1300 | next occurrences of this option will add or delete the listed system calls from the set of the filtered system | |
1301 | calls, depending of its type and the default action. (For example, if you have started with a whitelisting of | |
1302 | <function>read</function> and <function>write</function>, and right after it add a blacklisting of | |
1303 | <function>write</function>, then <function>write</function> will be removed from the set.)</para> | |
1304 | ||
1305 | <para>As the number of possible system calls is large, predefined sets of system calls are provided. A set | |
1306 | starts with <literal>@</literal> character, followed by name of the set. | |
201c1cc2 TM |
1307 | |
1308 | <table> | |
1309 | <title>Currently predefined system call sets</title> | |
1310 | ||
1311 | <tgroup cols='2'> | |
1312 | <colspec colname='set' /> | |
1313 | <colspec colname='description' /> | |
1314 | <thead> | |
1315 | <row> | |
1316 | <entry>Set</entry> | |
1317 | <entry>Description</entry> | |
1318 | </row> | |
1319 | </thead> | |
1320 | <tbody> | |
44898c53 LP |
1321 | <row> |
1322 | <entry>@aio</entry> | |
1323 | <entry>Asynchronous I/O (<citerefentry project='man-pages'><refentrytitle>io_setup</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>io_submit</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry> | |
1324 | </row> | |
133ddbbe LP |
1325 | <row> |
1326 | <entry>@basic-io</entry> | |
1327 | <entry>System calls for basic I/O: reading, writing, seeking, file descriptor duplication and closing (<citerefentry project='man-pages'><refentrytitle>read</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>write</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry> | |
1328 | </row> | |
44898c53 LP |
1329 | <row> |
1330 | <entry>@chown</entry> | |
1331 | <entry>Changing file ownership (<citerefentry project='man-pages'><refentrytitle>chown</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>fchownat</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry> | |
1332 | </row> | |
201c1cc2 TM |
1333 | <row> |
1334 | <entry>@clock</entry> | |
1f9ac68b LP |
1335 | <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> |
1336 | </row> | |
1337 | <row> | |
1338 | <entry>@cpu-emulation</entry> | |
1339 | <entry>System calls for CPU emulation functionality (<citerefentry project='man-pages'><refentrytitle>vm86</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry> | |
1340 | </row> | |
1341 | <row> | |
1342 | <entry>@debug</entry> | |
1343 | <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 | 1344 | </row> |
1a1b13c9 LP |
1345 | <row> |
1346 | <entry>@file-system</entry> | |
1347 | <entry>File system operations: opening, creating files and directories for read and write, renaming and removing them, reading file properties, or creating hard and symbolic links.</entry> | |
1348 | </row> | |
201c1cc2 TM |
1349 | <row> |
1350 | <entry>@io-event</entry> | |
1f9ac68b | 1351 | <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 |
1352 | </row> |
1353 | <row> | |
1354 | <entry>@ipc</entry> | |
cd5bfd7e | 1355 | <entry>Pipes, SysV IPC, POSIX Message Queues and 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> |
1f9ac68b LP |
1356 | </row> |
1357 | <row> | |
1358 | <entry>@keyring</entry> | |
1359 | <entry>Kernel keyring access (<citerefentry project='man-pages'><refentrytitle>keyctl</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry> | |
201c1cc2 | 1360 | </row> |
cd0ddf6f LP |
1361 | <row> |
1362 | <entry>@memlock</entry> | |
1363 | <entry>Locking of memory into RAM (<citerefentry project='man-pages'><refentrytitle>mlock</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>mlockall</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry> | |
1364 | </row> | |
201c1cc2 TM |
1365 | <row> |
1366 | <entry>@module</entry> | |
d5efc18b | 1367 | <entry>Loading and unloading of kernel modules (<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 |
1368 | </row> |
1369 | <row> | |
1370 | <entry>@mount</entry> | |
d5efc18b | 1371 | <entry>Mounting and unmounting of file systems (<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 |
1372 | </row> |
1373 | <row> | |
1374 | <entry>@network-io</entry> | |
1f9ac68b | 1375 | <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 |
1376 | </row> |
1377 | <row> | |
1378 | <entry>@obsolete</entry> | |
1f9ac68b | 1379 | <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 |
1380 | </row> |
1381 | <row> | |
1382 | <entry>@privileged</entry> | |
1f9ac68b | 1383 | <entry>All system calls which need super-user capabilities (<citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>)</entry> |
201c1cc2 TM |
1384 | </row> |
1385 | <row> | |
1386 | <entry>@process</entry> | |
d5efc18b | 1387 | <entry>Process control, execution, namespaceing operations (<citerefentry project='man-pages'><refentrytitle>clone</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 |
1388 | </row> |
1389 | <row> | |
1390 | <entry>@raw-io</entry> | |
aa6b9cec | 1391 | <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 | 1392 | </row> |
bd2ab3f4 LP |
1393 | <row> |
1394 | <entry>@reboot</entry> | |
1395 | <entry>System calls for rebooting and reboot preparation (<citerefentry project='man-pages'><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <function>kexec()</function>, …)</entry> | |
1396 | </row> | |
133ddbbe LP |
1397 | <row> |
1398 | <entry>@resources</entry> | |
1399 | <entry>System calls for changing resource limits, memory and scheduling parameters (<citerefentry project='man-pages'><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>setpriority</refentrytitle><manvolnum>2</manvolnum></citerefentry>, …)</entry> | |
1400 | </row> | |
6eaaeee9 LP |
1401 | <row> |
1402 | <entry>@setuid</entry> | |
1403 | <entry>System calls for changing user ID and group ID credentials, (<citerefentry project='man-pages'><refentrytitle>setuid</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>setgid</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>setresuid</refentrytitle><manvolnum>2</manvolnum></citerefentry>, …)</entry> | |
1404 | </row> | |
cd0ddf6f LP |
1405 | <row> |
1406 | <entry>@signal</entry> | |
1407 | <entry>System calls for manipulating and handling process signals (<citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>sigprocmask</refentrytitle><manvolnum>2</manvolnum></citerefentry>, …)</entry> | |
1408 | </row> | |
bd2ab3f4 LP |
1409 | <row> |
1410 | <entry>@swap</entry> | |
1411 | <entry>System calls for enabling/disabling swap devices (<citerefentry project='man-pages'><refentrytitle>swapon</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>swapoff</refentrytitle><manvolnum>2</manvolnum></citerefentry>)</entry> | |
1412 | </row> | |
44898c53 LP |
1413 | <row> |
1414 | <entry>@sync</entry> | |
1415 | <entry>Synchronizing files and memory to disk: (<citerefentry project='man-pages'><refentrytitle>fsync</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>msync</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry> | |
1416 | </row> | |
cd0ddf6f LP |
1417 | <row> |
1418 | <entry>@timer</entry> | |
1419 | <entry>System calls for scheduling operations by time (<citerefentry project='man-pages'><refentrytitle>alarm</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>timer_create</refentrytitle><manvolnum>2</manvolnum></citerefentry>, …)</entry> | |
1420 | </row> | |
201c1cc2 TM |
1421 | </tbody> |
1422 | </tgroup> | |
1423 | </table> | |
1424 | ||
b8afec21 LP |
1425 | Note, that as new system calls are added to the kernel, additional system calls might be added to the groups |
1426 | above. Contents of the sets may also change between systemd versions. In addition, the list of system calls | |
1427 | depends on the kernel version and architecture for which systemd was compiled. Use | |
1428 | <command>systemd-analyze syscall-filter</command> to list the actual list of system calls in each | |
1429 | filter.</para> | |
effbd6d2 LP |
1430 | |
1431 | <para>It is recommended to combine the file system namespacing related options with | |
1432 | <varname>SystemCallFilter=~@mount</varname>, in order to prohibit the unit's processes to undo the | |
1433 | mappings. Specifically these are the options <varname>PrivateTmp=</varname>, | |
1434 | <varname>PrivateDevices=</varname>, <varname>ProtectSystem=</varname>, <varname>ProtectHome=</varname>, | |
1435 | <varname>ProtectKernelTunables=</varname>, <varname>ProtectControlGroups=</varname>, | |
1436 | <varname>ReadOnlyPaths=</varname>, <varname>InaccessiblePaths=</varname> and | |
1437 | <varname>ReadWritePaths=</varname>.</para></listitem> | |
798d3a52 ZJS |
1438 | </varlistentry> |
1439 | ||
1440 | <varlistentry> | |
1441 | <term><varname>SystemCallErrorNumber=</varname></term> | |
1442 | ||
3df90f24 YW |
1443 | <listitem><para>Takes an <literal>errno</literal> error number (between 1 and 4095) or errno name such as |
1444 | <constant>EPERM</constant>, <constant>EACCES</constant> or <constant>EUCLEAN</constant>, to return when the | |
1445 | system call filter configured with <varname>SystemCallFilter=</varname> is triggered, instead of terminating | |
b8afec21 LP |
1446 | the process immediately. When this setting is not used, or when the empty string is assigned, the process will |
1447 | be terminated immediately when the filter is triggered.</para></listitem> | |
798d3a52 ZJS |
1448 | </varlistentry> |
1449 | ||
1450 | <varlistentry> | |
1451 | <term><varname>SystemCallArchitectures=</varname></term> | |
1452 | ||
0b8fab97 LP |
1453 | <listitem><para>Takes a space-separated list of architecture identifiers to include in the system call |
1454 | filter. The known architecture identifiers are the same as for <varname>ConditionArchitecture=</varname> | |
1455 | described in <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
1456 | as well as <constant>x32</constant>, <constant>mips64-n32</constant>, <constant>mips64-le-n32</constant>, and | |
2428aaf8 | 1457 | the special identifier <constant>native</constant>. The special identifier <constant>native</constant> |
62a0680b AJ |
1458 | implicitly maps to the native architecture of the system (or more precisely: to the architecture the system |
1459 | manager is compiled for). If running in user mode, or in system mode, but without the | |
1460 | <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting <varname>User=nobody</varname>), | |
1461 | <varname>NoNewPrivileges=yes</varname> is implied. By default, this option is set to the empty list, i.e. no | |
1462 | system call architecture filtering is applied.</para> | |
0b8fab97 | 1463 | |
2428aaf8 AJ |
1464 | <para>If this setting is used, processes of this unit will only be permitted to call native system calls, and |
1465 | system calls of the specified architectures. For the purposes of this option, the x32 architecture is treated | |
1466 | as including x86-64 system calls. However, this setting still fulfills its purpose, as explained below, on | |
1467 | x32.</para> | |
1468 | ||
1469 | <para>System call filtering is not equally effective on all architectures. For example, on x86 | |
0b8fab97 LP |
1470 | filtering of network socket-related calls is not possible, due to ABI limitations — a limitation that x86-64 |
1471 | does not have, however. On systems supporting multiple ABIs at the same time — such as x86/x86-64 — it is hence | |
1472 | recommended to limit the set of permitted system call architectures so that secondary ABIs may not be used to | |
1473 | circumvent the restrictions applied to the native ABI of the system. In particular, setting | |
c29ebc1a | 1474 | <varname>SystemCallArchitectures=native</varname> is a good choice for disabling non-native ABIs.</para> |
0b8fab97 | 1475 | |
b8afec21 LP |
1476 | <para>System call architectures may also be restricted system-wide via the |
1477 | <varname>SystemCallArchitectures=</varname> option in the global configuration. See | |
1478 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> for | |
1479 | details.</para></listitem> | |
1480 | </varlistentry> | |
1481 | ||
1482 | </variablelist> | |
1483 | </refsect1> | |
1484 | ||
1485 | <refsect1> | |
1486 | <title>Environment</title> | |
1487 | ||
1488 | <variablelist> | |
1489 | ||
1490 | <varlistentry> | |
1491 | <term><varname>Environment=</varname></term> | |
1492 | ||
1493 | <listitem><para>Sets environment variables for executed processes. Takes a space-separated list of variable | |
1494 | assignments. This option may be specified more than once, in which case all listed variables will be set. If | |
1495 | the same variable is set twice, the later setting will override the earlier setting. If the empty string is | |
1496 | assigned to this option, the list of environment variables is reset, all prior assignments have no | |
1497 | effect. Variable expansion is not performed inside the strings, however, specifier expansion is possible. The $ | |
1498 | character has no special meaning. If you need to assign a value containing spaces or the equals sign to a | |
1499 | variable, use double quotes (") for the assignment.</para> | |
1500 | ||
1501 | <para>Example: | |
1502 | <programlisting>Environment="VAR1=word1 word2" VAR2=word3 "VAR3=$word 5 6"</programlisting> | |
1503 | gives three variables <literal>VAR1</literal>, | |
1504 | <literal>VAR2</literal>, <literal>VAR3</literal> | |
1505 | with the values <literal>word1 word2</literal>, | |
1506 | <literal>word3</literal>, <literal>$word 5 6</literal>. | |
1507 | </para> | |
1508 | ||
1509 | <para> | |
1510 | See <citerefentry | |
1511 | project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details | |
1512 | about environment variables.</para></listitem> | |
1513 | </varlistentry> | |
1514 | ||
1515 | <varlistentry> | |
1516 | <term><varname>EnvironmentFile=</varname></term> | |
1517 | ||
1518 | <listitem><para>Similar to <varname>Environment=</varname> but reads the environment variables from a text | |
1519 | file. The text file should contain new-line-separated variable assignments. Empty lines, lines without an | |
1520 | <literal>=</literal> separator, or lines starting with ; or # will be ignored, which may be used for | |
1521 | commenting. A line ending with a backslash will be concatenated with the following one, allowing multiline | |
1522 | variable definitions. The parser strips leading and trailing whitespace from the values of assignments, unless | |
1523 | you use double quotes (").</para> | |
1524 | ||
1525 | <para>The argument passed should be an absolute filename or wildcard expression, optionally prefixed with | |
1526 | <literal>-</literal>, which indicates that if the file does not exist, it will not be read and no error or | |
1527 | warning message is logged. This option may be specified more than once in which case all specified files are | |
1528 | read. If the empty string is assigned to this option, the list of file to read is reset, all prior assignments | |
1529 | have no effect.</para> | |
1530 | ||
1531 | <para>The files listed with this directive will be read shortly before the process is executed (more | |
1532 | specifically, after all processes from a previous unit state terminated. This means you can generate these | |
1533 | files in one unit state, and read it with this option in the next).</para> | |
1534 | ||
1535 | <para>Settings from these files override settings made with <varname>Environment=</varname>. If the same | |
1536 | variable is set twice from these files, the files will be read in the order they are specified and the later | |
1537 | setting will override the earlier setting.</para></listitem> | |
1538 | </varlistentry> | |
1539 | ||
1540 | <varlistentry> | |
1541 | <term><varname>PassEnvironment=</varname></term> | |
1542 | ||
1543 | <listitem><para>Pass environment variables set for the system service manager to executed processes. Takes a | |
1544 | space-separated list of variable names. This option may be specified more than once, in which case all listed | |
1545 | variables will be passed. If the empty string is assigned to this option, the list of environment variables to | |
1546 | pass is reset, all prior assignments have no effect. Variables specified that are not set for the system | |
1547 | manager will not be passed and will be silently ignored. Note that this option is only relevant for the system | |
1548 | service manager, as system services by default do not automatically inherit any environment variables set for | |
1549 | the service manager itself. However, in case of the user service manager all environment variables are passed | |
1550 | to the executed processes anyway, hence this option is without effect for the user service manager.</para> | |
1551 | ||
1552 | <para>Variables set for invoked processes due to this setting are subject to being overridden by those | |
1553 | configured with <varname>Environment=</varname> or <varname>EnvironmentFile=</varname>.</para> | |
1554 | ||
1555 | <para>Example: | |
1556 | <programlisting>PassEnvironment=VAR1 VAR2 VAR3</programlisting> | |
1557 | passes three variables <literal>VAR1</literal>, | |
1558 | <literal>VAR2</literal>, <literal>VAR3</literal> | |
1559 | with the values set for those variables in PID1.</para> | |
1560 | ||
1561 | <para> | |
1562 | See <citerefentry | |
1563 | project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details | |
1564 | about environment variables.</para></listitem> | |
1565 | </varlistentry> | |
1566 | ||
1567 | <varlistentry> | |
1568 | <term><varname>UnsetEnvironment=</varname></term> | |
1569 | ||
1570 | <listitem><para>Explicitly unset environment variable assignments that would normally be passed from the | |
1571 | service manager to invoked processes of this unit. Takes a space-separated list of variable names or variable | |
1572 | assignments. This option may be specified more than once, in which case all listed variables/assignments will | |
1573 | be unset. If the empty string is assigned to this option, the list of environment variables/assignments to | |
1574 | unset is reset. If a variable assignment is specified (that is: a variable name, followed by | |
1575 | <literal>=</literal>, followed by its value), then any environment variable matching this precise assignment is | |
1576 | removed. If a variable name is specified (that is a variable name without any following <literal>=</literal> or | |
1577 | value), then any assignment matching the variable name, regardless of its value is removed. Note that the | |
1578 | effect of <varname>UnsetEnvironment=</varname> is applied as final step when the environment list passed to | |
1579 | executed processes is compiled. That means it may undo assignments from any configuration source, including | |
1580 | assignments made through <varname>Environment=</varname> or <varname>EnvironmentFile=</varname>, inherited from | |
1581 | the system manager's global set of environment variables, inherited via <varname>PassEnvironment=</varname>, | |
1582 | set by the service manager itself (such as <varname>$NOTIFY_SOCKET</varname> and such), or set by a PAM module | |
1583 | (in case <varname>PAMName=</varname> is used).</para> | |
1584 | ||
1585 | <para> | |
1586 | See <citerefentry | |
1587 | project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details | |
1588 | about environment variables.</para></listitem> | |
1589 | </varlistentry> | |
1590 | ||
1591 | </variablelist> | |
1592 | </refsect1> | |
1593 | ||
1594 | <refsect1> | |
1595 | <title>Logging and Standard Input/Output</title> | |
1596 | ||
1597 | <variablelist> | |
1598 | <varlistentry> | |
1599 | ||
1600 | <term><varname>StandardInput=</varname></term> | |
1601 | ||
1602 | <listitem><para>Controls where file descriptor 0 (STDIN) of the executed processes is connected to. Takes one | |
1603 | of <option>null</option>, <option>tty</option>, <option>tty-force</option>, <option>tty-fail</option>, | |
1604 | <option>data</option>, <option>file:<replaceable>path</replaceable></option>, <option>socket</option> or | |
1605 | <option>fd:<replaceable>name</replaceable></option>.</para> | |
1606 | ||
1607 | <para>If <option>null</option> is selected, standard input will be connected to <filename>/dev/null</filename>, | |
1608 | i.e. all read attempts by the process will result in immediate EOF.</para> | |
1609 | ||
1610 | <para>If <option>tty</option> is selected, standard input is connected to a TTY (as configured by | |
1611 | <varname>TTYPath=</varname>, see below) and the executed process becomes the controlling process of the | |
1612 | terminal. If the terminal is already being controlled by another process, the executed process waits until the | |
1613 | current controlling process releases the terminal.</para> | |
1614 | ||
1615 | <para><option>tty-force</option> is similar to <option>tty</option>, but the executed process is forcefully and | |
1616 | immediately made the controlling process of the terminal, potentially removing previous controlling processes | |
1617 | from the terminal.</para> | |
1618 | ||
1619 | <para><option>tty-fail</option> is similar to <option>tty</option>, but if the terminal already has a | |
1620 | controlling process start-up of the executed process fails.</para> | |
1621 | ||
1622 | <para>The <option>data</option> option may be used to configure arbitrary textual or binary data to pass via | |
1623 | standard input to the executed process. The data to pass is configured via | |
1624 | <varname>StandardInputText=</varname>/<varname>StandardInputData=</varname> (see below). Note that the actual | |
1625 | file descriptor type passed (memory file, regular file, UNIX pipe, …) might depend on the kernel and available | |
1626 | privileges. In any case, the file descriptor is read-only, and when read returns the specified data followed by | |
1627 | EOF.</para> | |
1628 | ||
1629 | <para>The <option>file:<replaceable>path</replaceable></option> option may be used to connect a specific file | |
1630 | system object to standard input. An absolute path following the <literal>:</literal> character is expected, | |
1631 | which may refer to a regular file, a FIFO or special file. If an <constant>AF_UNIX</constant> socket in the | |
1632 | file system is specified, a stream socket is connected to it. The latter is useful for connecting standard | |
1633 | input of processes to arbitrary system services.</para> | |
1634 | ||
1635 | <para>The <option>socket</option> option is valid in socket-activated services only, and requires the relevant | |
1636 | socket unit file (see | |
1637 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details) | |
1638 | to have <varname>Accept=yes</varname> set, or to specify a single socket only. If this option is set, standard | |
1639 | input will be connected to the socket the service was activated from, which is primarily useful for | |
1640 | compatibility with daemons designed for use with the traditional <citerefentry | |
1641 | project='freebsd'><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry> socket activation | |
1642 | daemon.</para> | |
1643 | ||
1644 | <para>The <option>fd:<replaceable>name</replaceable></option> option connects standard input to a specific, | |
1645 | named file descriptor provided by a socket unit. The name may be specified as part of this option, following a | |
1646 | <literal>:</literal> character (e.g. <literal>fd:foobar</literal>). If no name is specified, the name | |
1647 | <literal>stdin</literal> is implied (i.e. <literal>fd</literal> is equivalent to <literal>fd:stdin</literal>). | |
1648 | At least one socket unit defining the specified name must be provided via the <varname>Sockets=</varname> | |
1649 | option, and the file descriptor name may differ from the name of its containing socket unit. If multiple | |
1650 | matches are found, the first one will be used. See <varname>FileDescriptorName=</varname> in | |
1651 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more | |
1652 | details about named file descriptors and their ordering.</para> | |
1653 | ||
1654 | <para>This setting defaults to <option>null</option>.</para></listitem> | |
1655 | </varlistentry> | |
1656 | ||
1657 | <varlistentry> | |
1658 | <term><varname>StandardOutput=</varname></term> | |
1659 | ||
1660 | <listitem><para>Controls where file descriptor 1 (STDOUT) of the executed processes is connected to. Takes one | |
1661 | of <option>inherit</option>, <option>null</option>, <option>tty</option>, <option>journal</option>, | |
1662 | <option>syslog</option>, <option>kmsg</option>, <option>journal+console</option>, | |
1663 | <option>syslog+console</option>, <option>kmsg+console</option>, | |
1664 | <option>file:<replaceable>path</replaceable></option>, <option>socket</option> or | |
1665 | <option>fd:<replaceable>name</replaceable></option>.</para> | |
1666 | ||
1667 | <para><option>inherit</option> duplicates the file descriptor of standard input for standard output.</para> | |
1668 | ||
1669 | <para><option>null</option> connects standard output to <filename>/dev/null</filename>, i.e. everything written | |
1670 | to it will be lost.</para> | |
1671 | ||
1672 | <para><option>tty</option> connects standard output to a tty (as configured via <varname>TTYPath=</varname>, | |
1673 | see below). If the TTY is used for output only, the executed process will not become the controlling process of | |
1674 | the terminal, and will not fail or wait for other processes to release the terminal.</para> | |
1675 | ||
1676 | <para><option>journal</option> connects standard output with the journal which is accessible via | |
1677 | <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Note that | |
1678 | everything that is written to syslog or kmsg (see below) is implicitly stored in the journal as well, the | |
1679 | specific two options listed below are hence supersets of this one.</para> | |
1680 | ||
1681 | <para><option>syslog</option> connects standard output to the <citerefentry | |
1682 | project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> system syslog | |
1683 | service, in addition to the journal. Note that the journal daemon is usually configured to forward everything | |
1684 | it receives to syslog anyway, in which case this option is no different from <option>journal</option>.</para> | |
1685 | ||
1686 | <para><option>kmsg</option> connects standard output with the kernel log buffer which is accessible via | |
1687 | <citerefentry project='man-pages'><refentrytitle>dmesg</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
1688 | in addition to the journal. The journal daemon might be configured to send all logs to kmsg anyway, in which | |
1689 | case this option is no different from <option>journal</option>.</para> | |
1690 | ||
1691 | <para><option>journal+console</option>, <option>syslog+console</option> and <option>kmsg+console</option> work | |
1692 | in a similar way as the three options above but copy the output to the system console as well.</para> | |
1693 | ||
1694 | <para>The <option>file:<replaceable>path</replaceable></option> option may be used to connect a specific file | |
1695 | system object to standard output. The semantics are similar to the same option of | |
1696 | <varname>StandardInputText=</varname>, see above. If standard input and output are directed to the same file | |
1697 | path, it is opened only once, for reading as well as writing and duplicated. This is particular useful when the | |
1698 | specified path refers to an <constant>AF_UNIX</constant> socket in the file system, as in that case only a | |
1699 | single stream connection is created for both input and output.</para> | |
1700 | ||
1701 | <para><option>socket</option> connects standard output to a socket acquired via socket activation. The | |
1702 | semantics are similar to the same option of <varname>StandardInput=</varname>, see above.</para> | |
1703 | ||
1704 | <para>The <option>fd:<replaceable>name</replaceable></option> option connects standard output to a specific, | |
1705 | named file descriptor provided by a socket unit. A name may be specified as part of this option, following a | |
1706 | <literal>:</literal> character (e.g. <literal>fd:foobar</literal>). If no name is specified, the name | |
1707 | <literal>stdout</literal> is implied (i.e. <literal>fd</literal> is equivalent to | |
1708 | <literal>fd:stdout</literal>). At least one socket unit defining the specified name must be provided via the | |
1709 | <varname>Sockets=</varname> option, and the file descriptor name may differ from the name of its containing | |
1710 | socket unit. If multiple matches are found, the first one will be used. See | |
1711 | <varname>FileDescriptorName=</varname> in | |
1712 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more | |
1713 | details about named descriptors and their ordering.</para> | |
1714 | ||
1715 | <para>If the standard output (or error output, see below) of a unit is connected to the journal, syslog or the | |
1716 | kernel log buffer, the unit will implicitly gain a dependency of type <varname>After=</varname> on | |
1717 | <filename>systemd-journald.socket</filename> (also see the "Implicit Dependencies" section above). Also note | |
1718 | that in this case stdout (or stderr, see below) will be an <constant>AF_UNIX</constant> stream socket, and not | |
1719 | a pipe or FIFO that can be re-opened. This means when executing shell scripts the construct <command>echo | |
1720 | "hello" > /dev/stderr</command> for writing text to stderr will not work. To mitigate this use the construct | |
1721 | <command>echo "hello" >&2</command> instead, which is mostly equivalent and avoids this pitfall.</para> | |
1722 | ||
1723 | <para>This setting defaults to the value set with <varname>DefaultStandardOutput=</varname> in | |
1724 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, which | |
1725 | defaults to <option>journal</option>. Note that setting this parameter might result in additional dependencies | |
1726 | to be added to the unit (see above).</para></listitem> | |
1727 | </varlistentry> | |
1728 | ||
1729 | <varlistentry> | |
1730 | <term><varname>StandardError=</varname></term> | |
1731 | ||
1732 | <listitem><para>Controls where file descriptor 2 (STDERR) of the executed processes is connected to. The | |
1733 | available options are identical to those of <varname>StandardOutput=</varname>, with some exceptions: if set to | |
1734 | <option>inherit</option> the file descriptor used for standard output is duplicated for standard error, while | |
1735 | <option>fd:<replaceable>name</replaceable></option> will use a default file descriptor name of | |
1736 | <literal>stderr</literal>.</para> | |
1737 | ||
1738 | <para>This setting defaults to the value set with <varname>DefaultStandardError=</varname> in | |
1739 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, which | |
1740 | defaults to <option>inherit</option>. Note that setting this parameter might result in additional dependencies | |
1741 | to be added to the unit (see above).</para></listitem> | |
1742 | </varlistentry> | |
1743 | ||
1744 | <varlistentry> | |
1745 | <term><varname>StandardInputText=</varname></term> | |
1746 | <term><varname>StandardInputData=</varname></term> | |
1747 | ||
1748 | <listitem><para>Configures arbitrary textual or binary data to pass via file descriptor 0 (STDIN) to the | |
1749 | executed processes. These settings have no effect unless <varname>StandardInput=</varname> is set to | |
1750 | <option>data</option>. Use this option to embed process input data directly in the unit file.</para> | |
1751 | ||
1752 | <para><varname>StandardInputText=</varname> accepts arbitrary textual data. C-style escapes for special | |
1753 | characters as well as the usual <literal>%</literal>-specifiers are resolved. Each time this setting is used | |
1754 | the the specified text is appended to the per-unit data buffer, followed by a newline character (thus every use | |
1755 | appends a new line to the end of the buffer). Note that leading and trailing whitespace of lines configured | |
1756 | with this option is removed. If an empty line is specified the buffer is cleared (hence, in order to insert an | |
1757 | empty line, add an additional <literal>\n</literal> to the end or beginning of a line).</para> | |
1758 | ||
1759 | <para><varname>StandardInputData=</varname> accepts arbitrary binary data, encoded in <ulink | |
1760 | url="https://tools.ietf.org/html/rfc2045#section-6.8">Base64</ulink>. No escape sequences or specifiers are | |
1761 | resolved. Any whitespace in the encoded version is ignored during decoding.</para> | |
1762 | ||
1763 | <para>Note that <varname>StandardInputText=</varname> and <varname>StandardInputData=</varname> operate on the | |
1764 | same data buffer, and may be mixed in order to configure both binary and textual data for the same input | |
1765 | stream. The textual or binary data is joined strictly in the order the settings appear in the unit | |
1766 | file. Assigning an empty string to either will reset the data buffer.</para> | |
1767 | ||
1768 | <para>Please keep in mind that in order to maintain readability long unit file settings may be split into | |
1769 | multiple lines, by suffixing each line (except for the last) with a <literal>\</literal> character (see | |
1770 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for | |
1771 | details). This is particularly useful for large data configured with these two options. Example:</para> | |
1772 | ||
1773 | <programlisting>… | |
1774 | StandardInput=data | |
1775 | StandardInputData=SWNrIHNpdHplIGRhIHVuJyBlc3NlIEtsb3BzLAp1ZmYgZWVtYWwga2xvcHAncy4KSWNrIGtpZWtl \ | |
1776 | LCBzdGF1bmUsIHd1bmRyZSBtaXIsCnVmZiBlZW1hbCBqZWh0IHNlIHVmZiBkaWUgVMO8ci4KTmFu \ | |
1777 | dSwgZGVuayBpY2ssIGljayBkZW5rIG5hbnUhCkpldHogaXNzZSB1ZmYsIGVyc2NodCB3YXIgc2Ug \ | |
1778 | enUhCkljayBqZWhlIHJhdXMgdW5kIGJsaWNrZSDigJQKdW5kIHdlciBzdGVodCBkcmF1w59lbj8g \ | |
1779 | SWNrZSEK | |
1780 | …</programlisting></listitem> | |
798d3a52 ZJS |
1781 | </varlistentry> |
1782 | ||
1783 | <varlistentry> | |
b8afec21 | 1784 | <term><varname>LogLevelMax=</varname></term> |
142bd808 | 1785 | |
b8afec21 LP |
1786 | <listitem><para>Configures filtering by log level of log messages generated by this unit. Takes a |
1787 | <command>syslog</command> log level, one of <option>emerg</option> (lowest log level, only highest priority | |
1788 | messages), <option>alert</option>, <option>crit</option>, <option>err</option>, <option>warning</option>, | |
1789 | <option>notice</option>, <option>info</option>, <option>debug</option> (highest log level, also lowest priority | |
1790 | messages). See <citerefentry | |
1791 | project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> for | |
1792 | details. By default no filtering is applied (i.e. the default maximum log level is <option>debug</option>). Use | |
1793 | this option to configure the logging system to drop log messages of a specific service above the specified | |
1794 | level. For example, set <varname>LogLevelMax=</varname><option>info</option> in order to turn off debug logging | |
1795 | of a particularly chatty unit. Note that the the configured level is applied to any log messages written by any | |
1796 | of the processes belonging to this unit, sent via any supported logging protocol. The filtering is applied | |
1797 | early in the logging pipeline, before any kind of further processing is done. Moreover, messages which pass | |
1798 | through this filter successfully might still be dropped by filters applied at a later stage in the logging | |
1799 | subsystem. For example, <varname>MaxLevelStore=</varname> configured in | |
1800 | <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> might | |
1801 | prohibit messages of higher log levels to be stored on disk, even though the per-unit | |
1802 | <varname>LogLevelMax=</varname> permitted it to be processed.</para></listitem> | |
798d3a52 ZJS |
1803 | </varlistentry> |
1804 | ||
add00535 | 1805 | <varlistentry> |
b8afec21 | 1806 | <term><varname>LogExtraFields=</varname></term> |
add00535 | 1807 | |
b8afec21 LP |
1808 | <listitem><para>Configures additional log metadata fields to include in all log records generated by processes |
1809 | associated with this unit. This setting takes one or more journal field assignments in the format | |
1810 | <literal>FIELD=VALUE</literal> separated by whitespace. See | |
1811 | <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry> for | |
1812 | details on the journal field concept. Even though the underlying journal implementation permits binary field | |
1813 | values, this setting accepts only valid UTF-8 values. To include space characters in a journal field value, | |
1814 | enclose the assignment in double quotes ("). The usual specifiers are expanded in all assignments (see | |
1815 | below). Note that this setting is not only useful for attaching additional metadata to log records of a unit, | |
1816 | but given that all fields and values are indexed may also be used to implement cross-unit log record | |
1817 | matching. Assign an empty string to reset the list.</para></listitem> | |
add00535 LP |
1818 | </varlistentry> |
1819 | ||
798d3a52 | 1820 | <varlistentry> |
b8afec21 | 1821 | <term><varname>SyslogIdentifier=</varname></term> |
798d3a52 | 1822 | |
b8afec21 LP |
1823 | <listitem><para>Sets the process name ("<command>syslog</command> tag") to prefix log lines sent to the logging |
1824 | system or the kernel log buffer with. If not set, defaults to the process name of the executed process. This | |
1825 | option is only useful when <varname>StandardOutput=</varname> or <varname>StandardError=</varname> are set to | |
1826 | <option>journal</option>, <option>syslog</option> or <option>kmsg</option> (or to the same settings in | |
1827 | combination with <option>+console</option>) and only applies to log messages written to stdout or | |
1828 | stderr.</para></listitem> | |
798d3a52 ZJS |
1829 | </varlistentry> |
1830 | ||
1831 | <varlistentry> | |
b8afec21 | 1832 | <term><varname>SyslogFacility=</varname></term> |
78e864e5 | 1833 | |
b8afec21 LP |
1834 | <listitem><para>Sets the <command>syslog</command> facility identifier to use when logging. One of |
1835 | <option>kern</option>, <option>user</option>, <option>mail</option>, <option>daemon</option>, | |
1836 | <option>auth</option>, <option>syslog</option>, <option>lpr</option>, <option>news</option>, | |
1837 | <option>uucp</option>, <option>cron</option>, <option>authpriv</option>, <option>ftp</option>, | |
1838 | <option>local0</option>, <option>local1</option>, <option>local2</option>, <option>local3</option>, | |
1839 | <option>local4</option>, <option>local5</option>, <option>local6</option> or <option>local7</option>. See | |
1840 | <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
1841 | for details. This option is only useful when <varname>StandardOutput=</varname> or | |
1842 | <varname>StandardError=</varname> are set to <option>journal</option>, <option>syslog</option> or | |
1843 | <option>kmsg</option> (or to the same settings in combination with <option>+console</option>), and only applies | |
1844 | to log messages written to stdout or stderr. Defaults to <option>daemon</option>.</para></listitem> | |
78e864e5 TM |
1845 | </varlistentry> |
1846 | ||
b1edf445 | 1847 | <varlistentry> |
b8afec21 | 1848 | <term><varname>SyslogLevel=</varname></term> |
b1edf445 | 1849 | |
b8afec21 LP |
1850 | <listitem><para>The default <command>syslog</command> log level to use when logging to the logging system or |
1851 | the kernel log buffer. One of <option>emerg</option>, <option>alert</option>, <option>crit</option>, | |
1852 | <option>err</option>, <option>warning</option>, <option>notice</option>, <option>info</option>, | |
1853 | <option>debug</option>. See <citerefentry | |
1854 | project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> for | |
1855 | details. This option is only useful when <varname>StandardOutput=</varname> or | |
1856 | <varname>StandardError=</varname> are set to <option>journal</option>, <option>syslog</option> or | |
1857 | <option>kmsg</option> (or to the same settings in combination with <option>+console</option>), and only applies | |
1858 | to log messages written to stdout or stderr. Note that individual lines output by executed processes may be | |
1859 | prefixed with a different log level which can be used to override the default log level specified here. The | |
1860 | interpretation of these prefixes may be disabled with <varname>SyslogLevelPrefix=</varname>, see below. For | |
1861 | details, see <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
1862 | Defaults to <option>info</option>.</para></listitem> | |
78e864e5 TM |
1863 | </varlistentry> |
1864 | ||
1865 | <varlistentry> | |
b8afec21 | 1866 | <term><varname>SyslogLevelPrefix=</varname></term> |
4a628360 | 1867 | |
b8afec21 LP |
1868 | <listitem><para>Takes a boolean argument. If true and <varname>StandardOutput=</varname> or |
1869 | <varname>StandardError=</varname> are set to <option>journal</option>, <option>syslog</option> or | |
1870 | <option>kmsg</option> (or to the same settings in combination with <option>+console</option>), log lines | |
1871 | written by the executed process that are prefixed with a log level will be processed with this log level set | |
1872 | but the prefix removed. If set to false, the interpretation of these prefixes is disabled and the logged lines | |
1873 | are passed on as-is. This only applies to log messages written to stdout or stderr. For details about this | |
1874 | prefixing see <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
1875 | Defaults to true.</para></listitem> | |
1876 | </varlistentry> | |
fdfcb946 | 1877 | |
b8afec21 LP |
1878 | <varlistentry> |
1879 | <term><varname>TTYPath=</varname></term> | |
4a628360 | 1880 | |
b8afec21 LP |
1881 | <listitem><para>Sets the terminal device node to use if standard input, output, or error are connected to a TTY |
1882 | (see above). Defaults to <filename>/dev/console</filename>.</para></listitem> | |
1883 | </varlistentry> | |
23a7448e | 1884 | |
b8afec21 LP |
1885 | <varlistentry> |
1886 | <term><varname>TTYReset=</varname></term> | |
3536f49e | 1887 | |
b8afec21 LP |
1888 | <listitem><para>Reset the terminal device specified with <varname>TTYPath=</varname> before and after |
1889 | execution. Defaults to <literal>no</literal>.</para></listitem> | |
3536f49e YW |
1890 | </varlistentry> |
1891 | ||
189cd8c2 | 1892 | <varlistentry> |
b8afec21 | 1893 | <term><varname>TTYVHangup=</varname></term> |
189cd8c2 | 1894 | |
b8afec21 LP |
1895 | <listitem><para>Disconnect all clients which have opened the terminal device specified with |
1896 | <varname>TTYPath=</varname> before and after execution. Defaults to <literal>no</literal>.</para></listitem> | |
189cd8c2 ZJS |
1897 | </varlistentry> |
1898 | ||
53f47dfc | 1899 | <varlistentry> |
b8afec21 | 1900 | <term><varname>TTYVTDisallocate=</varname></term> |
53f47dfc | 1901 | |
b8afec21 LP |
1902 | <listitem><para>If the terminal device specified with <varname>TTYPath=</varname> is a virtual console |
1903 | terminal, try to deallocate the TTY before and after execution. This ensures that the screen and scrollback | |
1904 | buffer is cleared. Defaults to <literal>no</literal>.</para></listitem> | |
189cd8c2 | 1905 | </varlistentry> |
b8afec21 LP |
1906 | </variablelist> |
1907 | </refsect1> | |
1908 | ||
1909 | <refsect1> | |
1910 | <title>System V Compatibility</title> | |
1911 | <variablelist> | |
189cd8c2 | 1912 | |
f3e43635 | 1913 | <varlistentry> |
b8afec21 | 1914 | <term><varname>UtmpIdentifier=</varname></term> |
f3e43635 | 1915 | |
b8afec21 LP |
1916 | <listitem><para>Takes a four character identifier string for an <citerefentry |
1917 | project='man-pages'><refentrytitle>utmp</refentrytitle><manvolnum>5</manvolnum></citerefentry> and wtmp entry | |
1918 | for this service. This should only be set for services such as <command>getty</command> implementations (such | |
1919 | as <citerefentry | |
1920 | project='die-net'><refentrytitle>agetty</refentrytitle><manvolnum>8</manvolnum></citerefentry>) where utmp/wtmp | |
1921 | entries must be created and cleared before and after execution, or for services that shall be executed as if | |
1922 | they were run by a <command>getty</command> process (see below). If the configured string is longer than four | |
1923 | characters, it is truncated and the terminal four characters are used. This setting interprets %I style string | |
1924 | replacements. This setting is unset by default, i.e. no utmp/wtmp entries are created or cleaned up for this | |
1925 | service.</para></listitem> | |
f3e43635 TM |
1926 | </varlistentry> |
1927 | ||
f4170c67 | 1928 | <varlistentry> |
b8afec21 | 1929 | <term><varname>UtmpMode=</varname></term> |
f4170c67 | 1930 | |
b8afec21 LP |
1931 | <listitem><para>Takes one of <literal>init</literal>, <literal>login</literal> or <literal>user</literal>. If |
1932 | <varname>UtmpIdentifier=</varname> is set, controls which type of <citerefentry | |
1933 | project='man-pages'><refentrytitle>utmp</refentrytitle><manvolnum>5</manvolnum></citerefentry>/wtmp entries | |
1934 | for this service are generated. This setting has no effect unless <varname>UtmpIdentifier=</varname> is set | |
1935 | too. If <literal>init</literal> is set, only an <constant>INIT_PROCESS</constant> entry is generated and the | |
1936 | invoked process must implement a <command>getty</command>-compatible utmp/wtmp logic. If | |
1937 | <literal>login</literal> is set, first an <constant>INIT_PROCESS</constant> entry, followed by a | |
1938 | <constant>LOGIN_PROCESS</constant> entry is generated. In this case, the invoked process must implement a | |
1939 | <citerefentry | |
1940 | project='die-net'><refentrytitle>login</refentrytitle><manvolnum>1</manvolnum></citerefentry>-compatible | |
1941 | utmp/wtmp logic. If <literal>user</literal> is set, first an <constant>INIT_PROCESS</constant> entry, then a | |
1942 | <constant>LOGIN_PROCESS</constant> entry and finally a <constant>USER_PROCESS</constant> entry is | |
1943 | generated. In this case, the invoked process may be any process that is suitable to be run as session | |
1944 | leader. Defaults to <literal>init</literal>.</para></listitem> | |
f4170c67 LP |
1945 | </varlistentry> |
1946 | ||
798d3a52 ZJS |
1947 | </variablelist> |
1948 | </refsect1> | |
1949 | ||
1950 | <refsect1> | |
1951 | <title>Environment variables in spawned processes</title> | |
1952 | ||
00819cc1 LP |
1953 | <para>Processes started by the service manager are executed with an environment variable block assembled from |
1954 | multiple sources. Processes started by the system service manager generally do not inherit environment variables | |
1955 | set for the service manager itself (but this may be altered via <varname>PassEnvironment=</varname>), but processes | |
1956 | started by the user service manager instances generally do inherit all environment variables set for the service | |
1957 | manager itself.</para> | |
1958 | ||
1959 | <para>For each invoked process the list of environment variables set is compiled from the following sources:</para> | |
1960 | ||
1961 | <itemizedlist> | |
1962 | <listitem><para>Variables globally configured for the service manager, using the | |
1963 | <varname>DefaultEnvironment=</varname> setting in | |
1964 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, the kernel command line option <varname>systemd.setenv=</varname> (see | |
1965 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>) or via | |
1966 | <command>systemctl set-environment</command> (see <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>).</para></listitem> | |
1967 | ||
1968 | <listitem><para>Variables defined by the service manager itself (see the list below)</para></listitem> | |
1969 | ||
1970 | <listitem><para>Variables set in the service manager's own environment variable block (subject to <varname>PassEnvironment=</varname> for the system service manager)</para></listitem> | |
1971 | ||
1972 | <listitem><para>Variables set via <varname>Environment=</varname> in the unit file</para></listitem> | |
1973 | ||
606df9a5 | 1974 | <listitem><para>Variables read from files specified via <varname>EnvironmentFile=</varname> in the unit file</para></listitem> |
00819cc1 LP |
1975 | |
1976 | <listitem><para>Variables set by any PAM modules in case <varname>PAMName=</varname> is in effect, cf. <citerefentry project='man-pages'><refentrytitle>pam_env</refentrytitle><manvolnum>8</manvolnum></citerefentry></para></listitem> | |
1977 | </itemizedlist> | |
1978 | ||
1979 | <para>If the same environment variables are set by multiple of these sources, the later source — according to the | |
1980 | order of the list above — wins. Note that as final step all variables listed in | |
1981 | <varname>UnsetEnvironment=</varname> are removed again from the compiled environment variable list, immediately | |
1982 | before it is passed to the executed process.</para> | |
1983 | ||
1984 | <para>The following select environment variables are set by the service manager itself for each invoked process:</para> | |
798d3a52 ZJS |
1985 | |
1986 | <variablelist class='environment-variables'> | |
1987 | <varlistentry> | |
1988 | <term><varname>$PATH</varname></term> | |
1989 | ||
1990 | <listitem><para>Colon-separated list of directories to use | |
f95b0be7 | 1991 | when launching executables. systemd uses a fixed value of |
798d3a52 ZJS |
1992 | <filename>/usr/local/sbin</filename>:<filename>/usr/local/bin</filename>:<filename>/usr/sbin</filename>:<filename>/usr/bin</filename>:<filename>/sbin</filename>:<filename>/bin</filename>. |
1993 | </para></listitem> | |
1994 | </varlistentry> | |
1995 | ||
1996 | <varlistentry> | |
1997 | <term><varname>$LANG</varname></term> | |
1998 | ||
1999 | <listitem><para>Locale. Can be set in | |
3ba3a79d | 2000 | <citerefentry project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
798d3a52 ZJS |
2001 | or on the kernel command line (see |
2002 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
2003 | and | |
2004 | <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>). | |
2005 | </para></listitem> | |
2006 | </varlistentry> | |
2007 | ||
2008 | <varlistentry> | |
2009 | <term><varname>$USER</varname></term> | |
2010 | <term><varname>$LOGNAME</varname></term> | |
2011 | <term><varname>$HOME</varname></term> | |
2012 | <term><varname>$SHELL</varname></term> | |
2013 | ||
2014 | <listitem><para>User name (twice), home directory, and the | |
23deef88 LP |
2015 | login shell. The variables are set for the units that have |
2016 | <varname>User=</varname> set, which includes user | |
2017 | <command>systemd</command> instances. See | |
3ba3a79d | 2018 | <citerefentry project='die-net'><refentrytitle>passwd</refentrytitle><manvolnum>5</manvolnum></citerefentry>. |
798d3a52 ZJS |
2019 | </para></listitem> |
2020 | </varlistentry> | |
2021 | ||
4b58153d LP |
2022 | <varlistentry> |
2023 | <term><varname>$INVOCATION_ID</varname></term> | |
2024 | ||
2025 | <listitem><para>Contains a randomized, unique 128bit ID identifying each runtime cycle of the unit, formatted | |
2026 | as 32 character hexadecimal string. A new ID is assigned each time the unit changes from an inactive state into | |
2027 | an activating or active state, and may be used to identify this specific runtime cycle, in particular in data | |
2028 | stored offline, such as the journal. The same ID is passed to all processes run as part of the | |
2029 | unit.</para></listitem> | |
2030 | </varlistentry> | |
2031 | ||
798d3a52 ZJS |
2032 | <varlistentry> |
2033 | <term><varname>$XDG_RUNTIME_DIR</varname></term> | |
2034 | ||
2035 | <listitem><para>The directory for volatile state. Set for the | |
2036 | user <command>systemd</command> instance, and also in user | |
2037 | sessions. See | |
2038 | <citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>. | |
2039 | </para></listitem> | |
2040 | </varlistentry> | |
2041 | ||
2042 | <varlistentry> | |
2043 | <term><varname>$XDG_SESSION_ID</varname></term> | |
2044 | <term><varname>$XDG_SEAT</varname></term> | |
2045 | <term><varname>$XDG_VTNR</varname></term> | |
2046 | ||
2047 | <listitem><para>The identifier of the session, the seat name, | |
2048 | and virtual terminal of the session. Set by | |
2049 | <citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
2050 | for login sessions. <varname>$XDG_SEAT</varname> and | |
2051 | <varname>$XDG_VTNR</varname> will only be set when attached to | |
2052 | a seat and a tty.</para></listitem> | |
2053 | </varlistentry> | |
2054 | ||
2055 | <varlistentry> | |
2056 | <term><varname>$MAINPID</varname></term> | |
2057 | ||
2dd67817 | 2058 | <listitem><para>The PID of the unit's main process if it is |
798d3a52 ZJS |
2059 | known. This is only set for control processes as invoked by |
2060 | <varname>ExecReload=</varname> and similar. </para></listitem> | |
2061 | </varlistentry> | |
2062 | ||
2063 | <varlistentry> | |
2064 | <term><varname>$MANAGERPID</varname></term> | |
2065 | ||
2066 | <listitem><para>The PID of the user <command>systemd</command> | |
2067 | instance, set for processes spawned by it. </para></listitem> | |
2068 | </varlistentry> | |
2069 | ||
2070 | <varlistentry> | |
2071 | <term><varname>$LISTEN_FDS</varname></term> | |
2072 | <term><varname>$LISTEN_PID</varname></term> | |
5c019cf2 | 2073 | <term><varname>$LISTEN_FDNAMES</varname></term> |
798d3a52 ZJS |
2074 | |
2075 | <listitem><para>Information about file descriptors passed to a | |
2076 | service for socket activation. See | |
2077 | <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
2078 | </para></listitem> | |
2079 | </varlistentry> | |
2080 | ||
5c019cf2 EV |
2081 | <varlistentry> |
2082 | <term><varname>$NOTIFY_SOCKET</varname></term> | |
2083 | ||
2084 | <listitem><para>The socket | |
2085 | <function>sd_notify()</function> talks to. See | |
2086 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
2087 | </para></listitem> | |
2088 | </varlistentry> | |
2089 | ||
2090 | <varlistentry> | |
2091 | <term><varname>$WATCHDOG_PID</varname></term> | |
2092 | <term><varname>$WATCHDOG_USEC</varname></term> | |
2093 | ||
2094 | <listitem><para>Information about watchdog keep-alive notifications. See | |
2095 | <citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
2096 | </para></listitem> | |
2097 | </varlistentry> | |
2098 | ||
798d3a52 ZJS |
2099 | <varlistentry> |
2100 | <term><varname>$TERM</varname></term> | |
2101 | ||
2102 | <listitem><para>Terminal type, set only for units connected to | |
2103 | a terminal (<varname>StandardInput=tty</varname>, | |
2104 | <varname>StandardOutput=tty</varname>, or | |
2105 | <varname>StandardError=tty</varname>). See | |
2106 | <citerefentry project='man-pages'><refentrytitle>termcap</refentrytitle><manvolnum>5</manvolnum></citerefentry>. | |
2107 | </para></listitem> | |
2108 | </varlistentry> | |
7bce046b LP |
2109 | |
2110 | <varlistentry> | |
2111 | <term><varname>$JOURNAL_STREAM</varname></term> | |
2112 | ||
2113 | <listitem><para>If the standard output or standard error output of the executed processes are connected to the | |
2114 | journal (for example, by setting <varname>StandardError=journal</varname>) <varname>$JOURNAL_STREAM</varname> | |
2115 | contains the device and inode numbers of the connection file descriptor, formatted in decimal, separated by a | |
2116 | colon (<literal>:</literal>). This permits invoked processes to safely detect whether their standard output or | |
2117 | standard error output are connected to the journal. The device and inode numbers of the file descriptors should | |
2118 | be compared with the values set in the environment variable to determine whether the process output is still | |
2119 | connected to the journal. Note that it is generally not sufficient to only check whether | |
2120 | <varname>$JOURNAL_STREAM</varname> is set at all as services might invoke external processes replacing their | |
2121 | standard output or standard error output, without unsetting the environment variable.</para> | |
2122 | ||
ab2116b1 LP |
2123 | <para>If both standard output and standard error of the executed processes are connected to the journal via a |
2124 | stream socket, this environment variable will contain information about the standard error stream, as that's | |
2125 | usually the preferred destination for log data. (Note that typically the same stream is used for both standard | |
2126 | output and standard error, hence very likely the environment variable contains device and inode information | |
2127 | matching both stream file descriptors.)</para> | |
2128 | ||
7bce046b LP |
2129 | <para>This environment variable is primarily useful to allow services to optionally upgrade their used log |
2130 | protocol to the native journal protocol (using | |
2131 | <citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry> and other | |
2132 | functions) if their standard output or standard error output is connected to the journal anyway, thus enabling | |
2133 | delivery of structured metadata along with logged messages.</para></listitem> | |
2134 | </varlistentry> | |
136dc4c4 LP |
2135 | |
2136 | <varlistentry> | |
2137 | <term><varname>$SERVICE_RESULT</varname></term> | |
2138 | ||
2139 | <listitem><para>Only defined for the service unit type, this environment variable is passed to all | |
2140 | <varname>ExecStop=</varname> and <varname>ExecStopPost=</varname> processes, and encodes the service | |
38a7c3c0 LP |
2141 | "result". Currently, the following values are defined:</para> |
2142 | ||
2143 | <table> | |
2144 | <title>Defined <varname>$SERVICE_RESULT</varname> values</title> | |
2145 | <tgroup cols='2'> | |
2146 | <colspec colname='result'/> | |
2147 | <colspec colname='meaning'/> | |
2148 | <thead> | |
2149 | <row> | |
2150 | <entry>Value</entry> | |
2151 | <entry>Meaning</entry> | |
2152 | </row> | |
2153 | </thead> | |
2154 | ||
2155 | <tbody> | |
2156 | <row> | |
2157 | <entry><literal>success</literal></entry> | |
e124ccdf | 2158 | <entry>The service ran successfully and exited cleanly.</entry> |
38a7c3c0 LP |
2159 | </row> |
2160 | <row> | |
2161 | <entry><literal>protocol</literal></entry> | |
e124ccdf | 2162 | <entry>A protocol violation occurred: the service did not take the steps required by its unit configuration (specifically what is configured in its <varname>Type=</varname> setting).</entry> |
38a7c3c0 LP |
2163 | </row> |
2164 | <row> | |
2165 | <entry><literal>timeout</literal></entry> | |
e124ccdf | 2166 | <entry>One of the steps timed out.</entry> |
38a7c3c0 LP |
2167 | </row> |
2168 | <row> | |
2169 | <entry><literal>exit-code</literal></entry> | |
e124ccdf | 2170 | <entry>Service process exited with a non-zero exit code; see <varname>$EXIT_CODE</varname> below for the actual exit code returned.</entry> |
38a7c3c0 LP |
2171 | </row> |
2172 | <row> | |
2173 | <entry><literal>signal</literal></entry> | |
e124ccdf | 2174 | <entry>A service process was terminated abnormally by a signal, without dumping core. See <varname>$EXIT_CODE</varname> below for the actual signal causing the termination.</entry> |
38a7c3c0 LP |
2175 | </row> |
2176 | <row> | |
2177 | <entry><literal>core-dump</literal></entry> | |
e124ccdf | 2178 | <entry>A service process terminated abnormally with a signal and dumped core. See <varname>$EXIT_CODE</varname> below for the signal causing the termination.</entry> |
38a7c3c0 LP |
2179 | </row> |
2180 | <row> | |
2181 | <entry><literal>watchdog</literal></entry> | |
e124ccdf | 2182 | <entry>Watchdog keep-alive ping was enabled for the service, but the deadline was missed.</entry> |
38a7c3c0 LP |
2183 | </row> |
2184 | <row> | |
2185 | <entry><literal>start-limit-hit</literal></entry> | |
e124ccdf | 2186 | <entry>A start limit was defined for the unit and it was hit, causing the unit to fail to start. See <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s <varname>StartLimitIntervalSec=</varname> and <varname>StartLimitBurst=</varname> for details.</entry> |
38a7c3c0 LP |
2187 | </row> |
2188 | <row> | |
2189 | <entry><literal>resources</literal></entry> | |
2190 | <entry>A catch-all condition in case a system operation failed.</entry> | |
2191 | </row> | |
2192 | </tbody> | |
2193 | </tgroup> | |
2194 | </table> | |
136dc4c4 LP |
2195 | |
2196 | <para>This environment variable is useful to monitor failure or successful termination of a service. Even | |
2197 | though this variable is available in both <varname>ExecStop=</varname> and <varname>ExecStopPost=</varname>, it | |
2198 | is usually a better choice to place monitoring tools in the latter, as the former is only invoked for services | |
2199 | that managed to start up correctly, and the latter covers both services that failed during their start-up and | |
2200 | those which failed during their runtime.</para></listitem> | |
2201 | </varlistentry> | |
2202 | ||
2203 | <varlistentry> | |
2204 | <term><varname>$EXIT_CODE</varname></term> | |
2205 | <term><varname>$EXIT_STATUS</varname></term> | |
2206 | ||
2207 | <listitem><para>Only defined for the service unit type, these environment variables are passed to all | |
2208 | <varname>ExecStop=</varname>, <varname>ExecStopPost=</varname> processes and contain exit status/code | |
2209 | information of the main process of the service. For the precise definition of the exit code and status, see | |
2210 | <citerefentry><refentrytitle>wait</refentrytitle><manvolnum>2</manvolnum></citerefentry>. <varname>$EXIT_CODE</varname> | |
2211 | is one of <literal>exited</literal>, <literal>killed</literal>, | |
2212 | <literal>dumped</literal>. <varname>$EXIT_STATUS</varname> contains the numeric exit code formatted as string | |
2213 | if <varname>$EXIT_CODE</varname> is <literal>exited</literal>, and the signal name in all other cases. Note | |
2214 | that these environment variables are only set if the service manager succeeded to start and identify the main | |
e64e1bfd ZJS |
2215 | process of the service.</para> |
2216 | ||
2217 | <table> | |
2218 | <title>Summary of possible service result variable values</title> | |
2219 | <tgroup cols='3'> | |
2220 | <colspec colname='result' /> | |
e64e1bfd | 2221 | <colspec colname='code' /> |
a4e26faf | 2222 | <colspec colname='status' /> |
e64e1bfd ZJS |
2223 | <thead> |
2224 | <row> | |
2225 | <entry><varname>$SERVICE_RESULT</varname></entry> | |
e64e1bfd | 2226 | <entry><varname>$EXIT_CODE</varname></entry> |
a4e26faf | 2227 | <entry><varname>$EXIT_STATUS</varname></entry> |
e64e1bfd ZJS |
2228 | </row> |
2229 | </thead> | |
2230 | ||
2231 | <tbody> | |
38a7c3c0 LP |
2232 | <row> |
2233 | <entry valign="top"><literal>success</literal></entry> | |
2234 | <entry valign="top"><literal>exited</literal></entry> | |
2235 | <entry><literal>0</literal></entry> | |
2236 | </row> | |
a4e26faf JW |
2237 | <row> |
2238 | <entry morerows="1" valign="top"><literal>protocol</literal></entry> | |
2239 | <entry valign="top">not set</entry> | |
2240 | <entry>not set</entry> | |
2241 | </row> | |
2242 | <row> | |
2243 | <entry><literal>exited</literal></entry> | |
2244 | <entry><literal>0</literal></entry> | |
2245 | </row> | |
29df65f9 ZJS |
2246 | <row> |
2247 | <entry morerows="1" valign="top"><literal>timeout</literal></entry> | |
2248 | <entry valign="top"><literal>killed</literal></entry> | |
6757c06a | 2249 | <entry><literal>TERM</literal>, <literal>KILL</literal></entry> |
29df65f9 | 2250 | </row> |
29df65f9 ZJS |
2251 | <row> |
2252 | <entry valign="top"><literal>exited</literal></entry> | |
6757c06a LP |
2253 | <entry><literal>0</literal>, <literal>1</literal>, <literal>2</literal>, <literal |
2254 | >3</literal>, …, <literal>255</literal></entry> | |
29df65f9 | 2255 | </row> |
e64e1bfd ZJS |
2256 | <row> |
2257 | <entry valign="top"><literal>exit-code</literal></entry> | |
2258 | <entry valign="top"><literal>exited</literal></entry> | |
38a7c3c0 | 2259 | <entry><literal>1</literal>, <literal>2</literal>, <literal |
6757c06a | 2260 | >3</literal>, …, <literal>255</literal></entry> |
e64e1bfd | 2261 | </row> |
e64e1bfd ZJS |
2262 | <row> |
2263 | <entry valign="top"><literal>signal</literal></entry> | |
2264 | <entry valign="top"><literal>killed</literal></entry> | |
6757c06a | 2265 | <entry><literal>HUP</literal>, <literal>INT</literal>, <literal>KILL</literal>, …</entry> |
e64e1bfd | 2266 | </row> |
e64e1bfd ZJS |
2267 | <row> |
2268 | <entry valign="top"><literal>core-dump</literal></entry> | |
2269 | <entry valign="top"><literal>dumped</literal></entry> | |
6757c06a | 2270 | <entry><literal>ABRT</literal>, <literal>SEGV</literal>, <literal>QUIT</literal>, …</entry> |
e64e1bfd | 2271 | </row> |
e64e1bfd ZJS |
2272 | <row> |
2273 | <entry morerows="2" valign="top"><literal>watchdog</literal></entry> | |
2274 | <entry><literal>dumped</literal></entry> | |
2275 | <entry><literal>ABRT</literal></entry> | |
2276 | </row> | |
2277 | <row> | |
2278 | <entry><literal>killed</literal></entry> | |
6757c06a | 2279 | <entry><literal>TERM</literal>, <literal>KILL</literal></entry> |
e64e1bfd ZJS |
2280 | </row> |
2281 | <row> | |
2282 | <entry><literal>exited</literal></entry> | |
6757c06a LP |
2283 | <entry><literal>0</literal>, <literal>1</literal>, <literal>2</literal>, <literal |
2284 | >3</literal>, …, <literal>255</literal></entry> | |
e64e1bfd | 2285 | </row> |
38a7c3c0 LP |
2286 | <row> |
2287 | <entry><literal>start-limit-hit</literal></entry> | |
2288 | <entry>not set</entry> | |
2289 | <entry>not set</entry> | |
2290 | </row> | |
e64e1bfd ZJS |
2291 | <row> |
2292 | <entry><literal>resources</literal></entry> | |
2293 | <entry>any of the above</entry> | |
2294 | <entry>any of the above</entry> | |
2295 | </row> | |
29df65f9 | 2296 | <row> |
38a7c3c0 | 2297 | <entry namest="results" nameend="status">Note: the process may be also terminated by a signal not sent by systemd. In particular the process may send an arbitrary signal to itself in a handler for any of the non-maskable signals. Nevertheless, in the <literal>timeout</literal> and <literal>watchdog</literal> rows above only the signals that systemd sends have been included. Moreover, using <varname>SuccessExitStatus=</varname> additional exit statuses may be declared to indicate clean termination, which is not reflected by this table.</entry> |
29df65f9 | 2298 | </row> |
e64e1bfd ZJS |
2299 | </tbody> |
2300 | </tgroup> | |
2301 | </table> | |
2302 | ||
2303 | </listitem> | |
2304 | </varlistentry> | |
798d3a52 | 2305 | </variablelist> |
798d3a52 ZJS |
2306 | </refsect1> |
2307 | ||
91a8f867 JS |
2308 | <refsect1> |
2309 | <title>Process exit codes</title> | |
2310 | ||
2311 | <para>When invoking a unit process the service manager possibly fails to apply the execution parameters configured | |
2312 | with the settings above. In that case the already created service process will exit with a non-zero exit code | |
2313 | before the configured command line is executed. (Or in other words, the child process possibly exits with these | |
2314 | error codes, after having been created by the <citerefentry | |
2315 | project='man-pages'><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call, but | |
2316 | before the matching <citerefentry | |
2317 | project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call is | |
2318 | called.) Specifically, exit codes defined by the C library, by the LSB specification and by the systemd service | |
2319 | manager itself are used.</para> | |
2320 | ||
2321 | <para>The following basic service exit codes are defined by the C library.</para> | |
2322 | ||
2323 | <table> | |
2324 | <title>Basic C library exit codes</title> | |
2325 | <tgroup cols='3'> | |
2326 | <thead> | |
2327 | <row> | |
2328 | <entry>Exit Code</entry> | |
2329 | <entry>Symbolic Name</entry> | |
2330 | <entry>Description</entry> | |
2331 | </row> | |
2332 | </thead> | |
2333 | <tbody> | |
2334 | <row> | |
2335 | <entry>0</entry> | |
2336 | <entry><constant>EXIT_SUCCESS</constant></entry> | |
2337 | <entry>Generic success code.</entry> | |
2338 | </row> | |
2339 | <row> | |
2340 | <entry>1</entry> | |
2341 | <entry><constant>EXIT_FAILURE</constant></entry> | |
2342 | <entry>Generic failure or unspecified error.</entry> | |
2343 | </row> | |
2344 | </tbody> | |
2345 | </tgroup> | |
2346 | </table> | |
2347 | ||
2348 | <para>The following service exit codes are defined by the <ulink | |
2349 | url="https://refspecs.linuxbase.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/iniscrptact.html">LSB specification | |
2350 | </ulink>. | |
2351 | </para> | |
2352 | ||
2353 | <table> | |
2354 | <title>LSB service exit codes</title> | |
2355 | <tgroup cols='3'> | |
2356 | <thead> | |
2357 | <row> | |
2358 | <entry>Exit Code</entry> | |
2359 | <entry>Symbolic Name</entry> | |
2360 | <entry>Description</entry> | |
2361 | </row> | |
2362 | </thead> | |
2363 | <tbody> | |
2364 | <row> | |
2365 | <entry>2</entry> | |
2366 | <entry><constant>EXIT_INVALIDARGUMENT</constant></entry> | |
2367 | <entry>Invalid or excess arguments.</entry> | |
2368 | </row> | |
2369 | <row> | |
2370 | <entry>3</entry> | |
2371 | <entry><constant>EXIT_NOTIMPLEMENTED</constant></entry> | |
2372 | <entry>Unimplemented feature.</entry> | |
2373 | </row> | |
2374 | <row> | |
2375 | <entry>4</entry> | |
2376 | <entry><constant>EXIT_NOPERMISSION</constant></entry> | |
2377 | <entry>The user has insufficient privileges.</entry> | |
2378 | </row> | |
2379 | <row> | |
2380 | <entry>5</entry> | |
2381 | <entry><constant>EXIT_NOTINSTALLED</constant></entry> | |
2382 | <entry>The program is not installed.</entry> | |
2383 | </row> | |
2384 | <row> | |
2385 | <entry>6</entry> | |
2386 | <entry><constant>EXIT_NOTCONFIGURED</constant></entry> | |
2387 | <entry>The program is not configured.</entry> | |
2388 | </row> | |
2389 | <row> | |
2390 | <entry>7</entry> | |
2391 | <entry><constant>EXIT_NOTRUNNING</constant></entry> | |
2392 | <entry>The program is not running.</entry> | |
2393 | </row> | |
2394 | </tbody> | |
2395 | </tgroup> | |
2396 | </table> | |
2397 | ||
2398 | <para> | |
2399 | The LSB specification suggests that error codes 200 and above are reserved for implementations. Some of them are | |
2400 | used by the service manager to indicate problems during process invocation: | |
2401 | </para> | |
2402 | <table> | |
2403 | <title>systemd-specific exit codes</title> | |
2404 | <tgroup cols='3'> | |
2405 | <thead> | |
2406 | <row> | |
2407 | <entry>Exit Code</entry> | |
2408 | <entry>Symbolic Name</entry> | |
2409 | <entry>Description</entry> | |
2410 | </row> | |
2411 | </thead> | |
2412 | <tbody> | |
2413 | <row> | |
2414 | <entry>200</entry> | |
2415 | <entry><constant>EXIT_CHDIR</constant></entry> | |
2416 | <entry>Changing to the requested working directory failed. See <varname>WorkingDirectory=</varname> above.</entry> | |
2417 | </row> | |
2418 | <row> | |
2419 | <entry>201</entry> | |
2420 | <entry><constant>EXIT_NICE</constant></entry> | |
2421 | <entry>Failed to set up process scheduling priority (nice level). See <varname>Nice=</varname> above.</entry> | |
2422 | </row> | |
2423 | <row> | |
2424 | <entry>202</entry> | |
2425 | <entry><constant>EXIT_FDS</constant></entry> | |
2426 | <entry>Failed to close unwanted file descriptors, or to adjust passed file descriptors.</entry> | |
2427 | </row> | |
2428 | <row> | |
2429 | <entry>203</entry> | |
2430 | <entry><constant>EXIT_EXEC</constant></entry> | |
2431 | <entry>The actual process execution failed (specifically, the <citerefentry project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call). Most likely this is caused by a missing or non-accessible executable file.</entry> | |
2432 | </row> | |
2433 | <row> | |
2434 | <entry>204</entry> | |
2435 | <entry><constant>EXIT_MEMORY</constant></entry> | |
2436 | <entry>Failed to perform an action due to memory shortage.</entry> | |
2437 | </row> | |
2438 | <row> | |
2439 | <entry>205</entry> | |
2440 | <entry><constant>EXIT_LIMITS</constant></entry> | |
dcfaecc7 | 2441 | <entry>Failed to adjust resource limits. See <varname>LimitCPU=</varname> and related settings above.</entry> |
91a8f867 JS |
2442 | </row> |
2443 | <row> | |
2444 | <entry>206</entry> | |
2445 | <entry><constant>EXIT_OOM_ADJUST</constant></entry> | |
2446 | <entry>Failed to adjust the OOM setting. See <varname>OOMScoreAdjust=</varname> above.</entry> | |
2447 | </row> | |
2448 | <row> | |
2449 | <entry>207</entry> | |
2450 | <entry><constant>EXIT_SIGNAL_MASK</constant></entry> | |
2451 | <entry>Failed to set process signal mask.</entry> | |
2452 | </row> | |
2453 | <row> | |
2454 | <entry>208</entry> | |
2455 | <entry><constant>EXIT_STDIN</constant></entry> | |
2456 | <entry>Failed to set up standard input. See <varname>StandardInput=</varname> above.</entry> | |
2457 | </row> | |
2458 | <row> | |
2459 | <entry>209</entry> | |
2460 | <entry><constant>EXIT_STDOUT</constant></entry> | |
2461 | <entry>Failed to set up standard output. See <varname>StandardOutput=</varname> above.</entry> | |
2462 | </row> | |
2463 | <row> | |
2464 | <entry>210</entry> | |
2465 | <entry><constant>EXIT_CHROOT</constant></entry> | |
2466 | <entry>Failed to change root directory (<citerefentry project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry>). See <varname>RootDirectory=</varname>/<varname>RootImage=</varname> above.</entry> | |
2467 | </row> | |
2468 | <row> | |
2469 | <entry>211</entry> | |
2470 | <entry><constant>EXIT_IOPRIO</constant></entry> | |
2471 | <entry>Failed to set up IO scheduling priority. See <varname>IOSchedulingClass=</varname>/<varname>IOSchedulingPriority=</varname> above.</entry> | |
2472 | </row> | |
2473 | <row> | |
2474 | <entry>212</entry> | |
2475 | <entry><constant>EXIT_TIMERSLACK</constant></entry> | |
2476 | <entry>Failed to set up timer slack. See <varname>TimerSlackNSec=</varname> above.</entry> | |
2477 | </row> | |
2478 | <row> | |
2479 | <entry>213</entry> | |
2480 | <entry><constant>EXIT_SECUREBITS</constant></entry> | |
2481 | <entry>Failed to set process secure bits. See <varname>SecureBits=</varname> above.</entry> | |
2482 | </row> | |
2483 | <row> | |
2484 | <entry>214</entry> | |
2485 | <entry><constant>EXIT_SETSCHEDULER</constant></entry> | |
2486 | <entry>Failed to set up CPU scheduling. See <varname>CPUSchedulingPolicy=</varname>/<varname>CPUSchedulingPriority=</varname> above.</entry> | |
2487 | </row> | |
2488 | <row> | |
2489 | <entry>215</entry> | |
2490 | <entry><constant>EXIT_CPUAFFINITY</constant></entry> | |
2491 | <entry>Failed to set up CPU affinity. See <varname>CPUAffinity=</varname> above.</entry> | |
2492 | </row> | |
2493 | <row> | |
2494 | <entry>216</entry> | |
2495 | <entry><constant>EXIT_GROUP</constant></entry> | |
2496 | <entry>Failed to determine or change group credentials. See <varname>Group=</varname>/<varname>SupplementaryGroups=</varname> above.</entry> | |
2497 | </row> | |
2498 | <row> | |
2499 | <entry>217</entry> | |
2500 | <entry><constant>EXIT_USER</constant></entry> | |
2501 | <entry>Failed to determine or change user credentials, or to set up user namespacing. See <varname>User=</varname>/<varname>PrivateUsers=</varname> above.</entry> | |
2502 | </row> | |
2503 | <row> | |
2504 | <entry>218</entry> | |
2505 | <entry><constant>EXIT_CAPABILITIES</constant></entry> | |
2506 | <entry>Failed to drop capabilities, or apply ambient capabilities. See <varname>CapabilityBoundingSet=</varname>/<varname>AmbientCapabilities=</varname> above.</entry> | |
2507 | </row> | |
2508 | <row> | |
2509 | <entry>219</entry> | |
2510 | <entry><constant>EXIT_CGROUP</constant></entry> | |
2511 | <entry>Setting up the service control group failed.</entry> | |
2512 | </row> | |
2513 | <row> | |
2514 | <entry>220</entry> | |
2515 | <entry><constant>EXIT_SETSID</constant></entry> | |
2516 | <entry>Failed to create new process session.</entry> | |
2517 | </row> | |
2518 | <row> | |
2519 | <entry>221</entry> | |
2520 | <entry><constant>EXIT_CONFIRM</constant></entry> | |
2521 | <entry>Execution has been cancelled by the user. See the <varname>systemd.confirm_spawn=</varname> kernel command line setting on <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details.</entry> | |
2522 | </row> | |
2523 | <row> | |
2524 | <entry>222</entry> | |
2525 | <entry><constant>EXIT_STDERR</constant></entry> | |
2526 | <entry>Failed to set up standard error output. See <varname>StandardError=</varname> above.</entry> | |
2527 | </row> | |
2528 | <row> | |
2529 | <entry>224</entry> | |
2530 | <entry><constant>EXIT_PAM</constant></entry> | |
2531 | <entry>Failed to set up PAM session. See <varname>PAMName=</varname> above.</entry> | |
2532 | </row> | |
2533 | <row> | |
2534 | <entry>225</entry> | |
2535 | <entry><constant>EXIT_NETWORK</constant></entry> | |
2536 | <entry>Failed to set up network namespacing. See <varname>PrivateNetwork=</varname> above.</entry> | |
2537 | </row> | |
2538 | <row> | |
2539 | <entry>226</entry> | |
2540 | <entry><constant>EXIT_NAMESPACE</constant></entry> | |
2541 | <entry>Failed to set up mount namespacing. See <varname>ReadOnlyPaths=</varname> and related settings above.</entry> | |
2542 | </row> | |
2543 | <row> | |
2544 | <entry>227</entry> | |
2545 | <entry><constant>EXIT_NO_NEW_PRIVILEGES</constant></entry> | |
dcfaecc7 | 2546 | <entry>Failed to disable new privileges. See <varname>NoNewPrivileges=yes</varname> above.</entry> |
91a8f867 JS |
2547 | </row> |
2548 | <row> | |
2549 | <entry>228</entry> | |
2550 | <entry><constant>EXIT_SECCOMP</constant></entry> | |
2551 | <entry>Failed to apply system call filters. See <varname>SystemCallFilter=</varname> and related settings above.</entry> | |
2552 | </row> | |
2553 | <row> | |
2554 | <entry>229</entry> | |
2555 | <entry><constant>EXIT_SELINUX_CONTEXT</constant></entry> | |
2556 | <entry>Determining or changing SELinux context failed. See <varname>SELinuxContext=</varname> above.</entry> | |
2557 | </row> | |
2558 | <row> | |
2559 | <entry>230</entry> | |
2560 | <entry><constant>EXIT_PERSONALITY</constant></entry> | |
dcfaecc7 | 2561 | <entry>Failed to set up an execution domain (personality). See <varname>Personality=</varname> above.</entry> |
91a8f867 JS |
2562 | </row> |
2563 | <row> | |
2564 | <entry>231</entry> | |
2565 | <entry><constant>EXIT_APPARMOR_PROFILE</constant></entry> | |
2566 | <entry>Failed to prepare changing AppArmor profile. See <varname>AppArmorProfile=</varname> above.</entry> | |
2567 | </row> | |
2568 | <row> | |
2569 | <entry>232</entry> | |
2570 | <entry><constant>EXIT_ADDRESS_FAMILIES</constant></entry> | |
2571 | <entry>Failed to restrict address families. See <varname>RestrictAddressFamilies=</varname> above.</entry> | |
2572 | </row> | |
2573 | <row> | |
2574 | <entry>233</entry> | |
2575 | <entry><constant>EXIT_RUNTIME_DIRECTORY</constant></entry> | |
2576 | <entry>Setting up runtime directory failed. See <varname>RuntimeDirectory=</varname> and related settings above.</entry> | |
2577 | </row> | |
2578 | <row> | |
2579 | <entry>235</entry> | |
2580 | <entry><constant>EXIT_CHOWN</constant></entry> | |
2581 | <entry>Failed to adjust socket ownership. Used for socket units only.</entry> | |
2582 | </row> | |
2583 | <row> | |
2584 | <entry>236</entry> | |
2585 | <entry><constant>EXIT_SMACK_PROCESS_LABEL</constant></entry> | |
2586 | <entry>Failed to set SMACK label. See <varname>SmackProcessLabel=</varname> above.</entry> | |
2587 | </row> | |
2588 | <row> | |
2589 | <entry>237</entry> | |
2590 | <entry><constant>EXIT_KEYRING</constant></entry> | |
2591 | <entry>Failed to set up kernel keyring.</entry> | |
2592 | </row> | |
2593 | <row> | |
2594 | <entry>238</entry> | |
2595 | <entry><constant>EXIT_STATE_DIRECTORY</constant></entry> | |
dcfaecc7 | 2596 | <entry>Failed to set up unit's state directory. See <varname>StateDirectory=</varname> above.</entry> |
91a8f867 JS |
2597 | </row> |
2598 | <row> | |
2599 | <entry>239</entry> | |
2600 | <entry><constant>EXIT_CACHE_DIRECTORY</constant></entry> | |
dcfaecc7 | 2601 | <entry>Failed to set up unit's cache directory. See <varname>CacheDirectory=</varname> above.</entry> |
91a8f867 JS |
2602 | </row> |
2603 | <row> | |
2604 | <entry>240</entry> | |
2605 | <entry><constant>EXIT_LOGS_DIRECTORY</constant></entry> | |
dcfaecc7 | 2606 | <entry>Failed to set up unit's logging directory. See <varname>LogsDirectory=</varname> above.</entry> |
91a8f867 JS |
2607 | </row> |
2608 | <row> | |
2609 | <entry>241</entry> | |
2610 | <entry><constant>EXIT_CONFIGURATION_DIRECTORY</constant></entry> | |
dcfaecc7 | 2611 | <entry>Failed to set up unit's configuration directory. See <varname>ConfigurationDirectory=</varname> above.</entry> |
91a8f867 JS |
2612 | </row> |
2613 | </tbody> | |
2614 | </tgroup> | |
2615 | </table> | |
2616 | </refsect1> | |
2617 | ||
798d3a52 ZJS |
2618 | <refsect1> |
2619 | <title>See Also</title> | |
2620 | <para> | |
2621 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
2622 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
869feb33 | 2623 | <citerefentry><refentrytitle>systemd-analyze</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
798d3a52 ZJS |
2624 | <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
2625 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
2626 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
2627 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
2628 | <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
2629 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
2630 | <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
2631 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
a4c18002 | 2632 | <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
798d3a52 ZJS |
2633 | <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
2634 | <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
2635 | <citerefentry project='man-pages'><refentrytitle>exec</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
2636 | </para> | |
2637 | </refsect1> | |
dd1eb43b | 2638 | |
e64e1bfd | 2639 | |
dd1eb43b | 2640 | </refentry> |