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514094f9 | 1 | <?xml version='1.0'?> |
3a54a157 | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
0307f791 | 4 | <!-- SPDX-License-Identifier: LGPL-2.1+ --> |
dd1eb43b | 5 | |
c4d4b5a7 | 6 | <refentry id="systemd.exec" xmlns:xi="http://www.w3.org/2001/XInclude"> |
798d3a52 ZJS |
7 | <refentryinfo> |
8 | <title>systemd.exec</title> | |
9 | <productname>systemd</productname> | |
798d3a52 ZJS |
10 | </refentryinfo> |
11 | ||
12 | <refmeta> | |
13 | <refentrytitle>systemd.exec</refentrytitle> | |
14 | <manvolnum>5</manvolnum> | |
15 | </refmeta> | |
16 | ||
17 | <refnamediv> | |
18 | <refname>systemd.exec</refname> | |
19 | <refpurpose>Execution environment configuration</refpurpose> | |
20 | </refnamediv> | |
21 | ||
22 | <refsynopsisdiv> | |
23 | <para><filename><replaceable>service</replaceable>.service</filename>, | |
24 | <filename><replaceable>socket</replaceable>.socket</filename>, | |
25 | <filename><replaceable>mount</replaceable>.mount</filename>, | |
26 | <filename><replaceable>swap</replaceable>.swap</filename></para> | |
27 | </refsynopsisdiv> | |
28 | ||
29 | <refsect1> | |
30 | <title>Description</title> | |
31 | ||
b8afec21 LP |
32 | <para>Unit configuration files for services, sockets, mount points, and swap devices share a subset of |
33 | configuration options which define the execution environment of spawned processes.</para> | |
34 | ||
35 | <para>This man page lists the configuration options shared by these four unit types. See | |
36 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for the common | |
37 | options of all unit configuration files, and | |
798d3a52 ZJS |
38 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
39 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
b8afec21 LP |
40 | <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>, and |
41 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more | |
42 | information on the specific unit configuration files. The execution specific configuration options are configured | |
43 | in the [Service], [Socket], [Mount], or [Swap] sections, depending on the unit type.</para> | |
74b47bbd | 44 | |
c7458f93 | 45 | <para>In addition, options which control resources through Linux Control Groups (cgroups) are listed in |
74b47bbd ZJS |
46 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>. |
47 | Those options complement options listed here.</para> | |
798d3a52 ZJS |
48 | </refsect1> |
49 | ||
c129bd5d | 50 | <refsect1> |
45f09f93 JL |
51 | <title>Implicit Dependencies</title> |
52 | ||
53 | <para>A few execution parameters result in additional, automatic dependencies to be added:</para> | |
54 | ||
55 | <itemizedlist> | |
b8afec21 LP |
56 | <listitem><para>Units with <varname>WorkingDirectory=</varname>, <varname>RootDirectory=</varname>, |
57 | <varname>RootImage=</varname>, <varname>RuntimeDirectory=</varname>, <varname>StateDirectory=</varname>, | |
58 | <varname>CacheDirectory=</varname>, <varname>LogsDirectory=</varname> or | |
59 | <varname>ConfigurationDirectory=</varname> set automatically gain dependencies of type | |
60 | <varname>Requires=</varname> and <varname>After=</varname> on all mount units required to access the specified | |
61 | paths. This is equivalent to having them listed explicitly in | |
62 | <varname>RequiresMountsFor=</varname>.</para></listitem> | |
63 | ||
64 | <listitem><para>Similar, units with <varname>PrivateTmp=</varname> enabled automatically get mount unit | |
65 | dependencies for all mounts required to access <filename>/tmp</filename> and <filename>/var/tmp</filename>. They | |
66 | will also gain an automatic <varname>After=</varname> dependency on | |
45f09f93 JL |
67 | <citerefentry><refentrytitle>systemd-tmpfiles-setup.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para></listitem> |
68 | ||
d2b84355 LP |
69 | <listitem><para>Units whose standard output or error output is connected to <option>journal</option> or |
70 | <option>kmsg</option> (or their combinations with console output, see below) automatically acquire | |
71 | dependencies of type <varname>After=</varname> on | |
b8afec21 | 72 | <filename>systemd-journald.socket</filename>.</para></listitem> |
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73 | |
74 | <listitem><para>Units using <varname>LogNamespace=</varname> will automatically gain ordering and | |
75 | requirement dependencies on the two socket units associated with | |
76 | <filename>systemd-journald@.service</filename> instances.</para></listitem> | |
45f09f93 | 77 | </itemizedlist> |
c129bd5d LP |
78 | </refsect1> |
79 | ||
45f09f93 JL |
80 | <!-- We don't have any default dependency here. --> |
81 | ||
798d3a52 | 82 | <refsect1> |
b8afec21 | 83 | <title>Paths</title> |
798d3a52 | 84 | |
1448dfa6 AK |
85 | <para>The following settings may be used to change a service's view of the filesystem. Please note that the paths |
86 | must be absolute and must not contain a <literal>..</literal> path component.</para> | |
87 | ||
798d3a52 ZJS |
88 | <variablelist class='unit-directives'> |
89 | ||
90 | <varlistentry> | |
91 | <term><varname>WorkingDirectory=</varname></term> | |
92 | ||
d251207d LP |
93 | <listitem><para>Takes a directory path relative to the service's root directory specified by |
94 | <varname>RootDirectory=</varname>, or the special value <literal>~</literal>. Sets the working directory for | |
95 | executed processes. If set to <literal>~</literal>, the home directory of the user specified in | |
96 | <varname>User=</varname> is used. If not set, defaults to the root directory when systemd is running as a | |
97 | system instance and the respective user's home directory if run as user. If the setting is prefixed with the | |
98 | <literal>-</literal> character, a missing working directory is not considered fatal. If | |
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99 | <varname>RootDirectory=</varname>/<varname>RootImage=</varname> is not set, then |
100 | <varname>WorkingDirectory=</varname> is relative to the root of the system running the service manager. Note | |
101 | that setting this parameter might result in additional dependencies to be added to the unit (see | |
102 | above).</para></listitem> | |
798d3a52 ZJS |
103 | </varlistentry> |
104 | ||
105 | <varlistentry> | |
106 | <term><varname>RootDirectory=</varname></term> | |
107 | ||
d251207d LP |
108 | <listitem><para>Takes a directory path relative to the host's root directory (i.e. the root of the system |
109 | running the service manager). Sets the root directory for executed processes, with the <citerefentry | |
110 | project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry> system | |
111 | call. If this is used, it must be ensured that the process binary and all its auxiliary files are available in | |
112 | the <function>chroot()</function> jail. Note that setting this parameter might result in additional | |
113 | dependencies to be added to the unit (see above).</para> | |
114 | ||
5d997827 | 115 | <para>The <varname>MountAPIVFS=</varname> and <varname>PrivateUsers=</varname> settings are particularly useful |
c4d4b5a7 LP |
116 | in conjunction with <varname>RootDirectory=</varname>. For details, see below.</para> |
117 | ||
118 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
5d997827 LP |
119 | </varlistentry> |
120 | ||
915e6d16 LP |
121 | <varlistentry> |
122 | <term><varname>RootImage=</varname></term> | |
b8afec21 | 123 | |
19ac32cd LP |
124 | <listitem><para>Takes a path to a block device node or regular file as argument. This call is similar |
125 | to <varname>RootDirectory=</varname> however mounts a file system hierarchy from a block device node | |
126 | or loopback file instead of a directory. The device node or file system image file needs to contain a | |
127 | file system without a partition table, or a file system within an MBR/MS-DOS or GPT partition table | |
128 | with only a single Linux-compatible partition, or a set of file systems within a GPT partition table | |
129 | that follows the <ulink url="https://systemd.io/DISCOVERABLE_PARTITIONS">Discoverable Partitions | |
fe65e88b YW |
130 | Specification</ulink>.</para> |
131 | ||
c4d4b5a7 LP |
132 | <para>When <varname>DevicePolicy=</varname> is set to <literal>closed</literal> or |
133 | <literal>strict</literal>, or set to <literal>auto</literal> and <varname>DeviceAllow=</varname> is | |
134 | set, then this setting adds <filename>/dev/loop-control</filename> with <constant>rw</constant> mode, | |
135 | <literal>block-loop</literal> and <literal>block-blkext</literal> with <constant>rwm</constant> mode | |
136 | to <varname>DeviceAllow=</varname>. See | |
fe65e88b YW |
137 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
138 | for the details about <varname>DevicePolicy=</varname> or <varname>DeviceAllow=</varname>. Also, see | |
c4d4b5a7 LP |
139 | <varname>PrivateDevices=</varname> below, as it may change the setting of |
140 | <varname>DevicePolicy=</varname>.</para> | |
141 | ||
33b58dfb LP |
142 | <para>Units making use of <varname>RootImage=</varname> automatically gain an |
143 | <varname>After=</varname> dependency on <filename>systemd-udevd.service</filename>.</para> | |
144 | ||
c4d4b5a7 | 145 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> |
915e6d16 LP |
146 | </varlistentry> |
147 | ||
18d73705 LB |
148 | <varlistentry> |
149 | <term><varname>RootImageOptions=</varname></term> | |
150 | ||
151 | <listitem><para>Takes a comma-separated list of mount options that will be used on disk images specified by | |
152 | <varname>RootImage=</varname>. Optionally a partition number can be prefixed, followed by colon, in | |
153 | case the image has multiple partitions, otherwise partition number 0 is implied. | |
154 | Options for multiple partitions can be specified in a single line with space separators. Assigning an empty | |
155 | string removes previous assignments. For a list of valid mount options, please refer to | |
156 | <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
157 | ||
158 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
159 | </varlistentry> | |
160 | ||
0389f4fa LB |
161 | <varlistentry> |
162 | <term><varname>RootHash=</varname></term> | |
163 | ||
164 | <listitem><para>Takes a data integrity (dm-verity) root hash specified in hexadecimal, or the path to a file | |
165 | containing a root hash in ASCII hexadecimal format. This option enables data integrity checks using dm-verity, | |
166 | if the used image contains the appropriate integrity data (see above) or if <varname>RootVerity=</varname> is used. | |
167 | The specified hash must match the root hash of integrity data, and is usually at least 256 bits (and hence 64 | |
168 | formatted hexadecimal characters) long (in case of SHA256 for example). If this option is not specified, but | |
169 | the image file carries the <literal>user.verity.roothash</literal> extended file attribute (see <citerefentry | |
170 | project='man-pages'><refentrytitle>xattr</refentrytitle><manvolnum>7</manvolnum></citerefentry>), then the root | |
171 | hash is read from it, also as formatted hexadecimal characters. If the extended file attribute is not found (or | |
172 | is not supported by the underlying file system), but a file with the <filename>.roothash</filename> suffix is | |
173 | found next to the image file, bearing otherwise the same name (except if the image has the | |
174 | <filename>.raw</filename> suffix, in which case the root hash file must not have it in its name), the root hash | |
175 | is read from it and automatically used, also as formatted hexadecimal characters.</para> | |
176 | ||
177 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
178 | </varlistentry> | |
179 | ||
d4d55b0d LB |
180 | <varlistentry> |
181 | <term><varname>RootHashSignature=</varname></term> | |
182 | ||
183 | <listitem><para>Takes a PKCS7 formatted binary signature of the <varname>RootHash=</varname> option as a path | |
184 | to a DER encoded signature file or as an ASCII base64 string encoding of the DER encoded signature, prefixed | |
185 | by <literal>base64:</literal>. The dm-verity volume will only be opened if the signature of the root hash | |
186 | signature is valid and created by a public key present in the kernel keyring. If this option is not specified, | |
187 | but a file with the <filename>.roothash.p7s</filename> suffix is found next to the image file, bearing otherwise | |
188 | the same name (except if the image has the <filename>.raw</filename> suffix, in which case the signature file | |
189 | must not have it in its name), the signature is read from it and automatically used.</para> | |
190 | ||
191 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
192 | </varlistentry> | |
193 | ||
0389f4fa LB |
194 | <varlistentry> |
195 | <term><varname>RootVerity=</varname></term> | |
196 | ||
197 | <listitem><para>Takes the path to a data integrity (dm-verity) file. This option enables data integrity checks | |
198 | using dm-verity, if <varname>RootImage=</varname> is used and a root-hash is passed and if the used image itself | |
199 | does not contains the integrity data. The integrity data must be matched by the root hash. If this option is not | |
200 | specified, but a file with the <filename>.verity</filename> suffix is found next to the image file, bearing otherwise | |
201 | the same name (except if the image has the <filename>.raw</filename> suffix, in which case the verity data file must | |
202 | not have it in its name), the verity data is read from it and automatically used.</para> | |
203 | ||
6b222c4b LP |
204 | <para>This option is supported only for disk images that contain a single file system, without an |
205 | enveloping partition table. Images that contain a GPT partition table should instead include both | |
206 | root file system and matching Verity data in the same image, implementing the <ulink | |
207 | url="https://systemd.io/DISCOVERABLE_PARTITIONS">Discoverable Partition Specification</ulink>.</para> | |
0389f4fa LB |
208 | |
209 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
210 | </varlistentry> | |
211 | ||
5d997827 LP |
212 | <varlistentry> |
213 | <term><varname>MountAPIVFS=</varname></term> | |
214 | ||
215 | <listitem><para>Takes a boolean argument. If on, a private mount namespace for the unit's processes is created | |
ef3116b5 ZJS |
216 | and the API file systems <filename>/proc</filename>, <filename>/sys</filename>, and <filename>/dev</filename> |
217 | are mounted inside of it, unless they are already mounted. Note that this option has no effect unless used in | |
218 | conjunction with <varname>RootDirectory=</varname>/<varname>RootImage=</varname> as these three mounts are | |
219 | generally mounted in the host anyway, and unless the root directory is changed, the private mount namespace | |
220 | will be a 1:1 copy of the host's, and include these three mounts. Note that the <filename>/dev</filename> file | |
221 | system of the host is bind mounted if this option is used without <varname>PrivateDevices=</varname>. To run | |
222 | the service with a private, minimal version of <filename>/dev/</filename>, combine this option with | |
c4d4b5a7 LP |
223 | <varname>PrivateDevices=</varname>.</para> |
224 | ||
225 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
798d3a52 ZJS |
226 | </varlistentry> |
227 | ||
b8afec21 LP |
228 | <varlistentry> |
229 | <term><varname>BindPaths=</varname></term> | |
230 | <term><varname>BindReadOnlyPaths=</varname></term> | |
231 | ||
232 | <listitem><para>Configures unit-specific bind mounts. A bind mount makes a particular file or directory | |
233 | available at an additional place in the unit's view of the file system. Any bind mounts created with this | |
234 | option are specific to the unit, and are not visible in the host's mount table. This option expects a | |
235 | whitespace separated list of bind mount definitions. Each definition consists of a colon-separated triple of | |
236 | source path, destination path and option string, where the latter two are optional. If only a source path is | |
237 | specified the source and destination is taken to be the same. The option string may be either | |
238 | <literal>rbind</literal> or <literal>norbind</literal> for configuring a recursive or non-recursive bind | |
4ca763a9 YW |
239 | mount. If the destination path is omitted, the option string must be omitted too. |
240 | Each bind mount definition may be prefixed with <literal>-</literal>, in which case it will be ignored | |
241 | when its source path does not exist.</para> | |
b8afec21 LP |
242 | |
243 | <para><varname>BindPaths=</varname> creates regular writable bind mounts (unless the source file system mount | |
244 | is already marked read-only), while <varname>BindReadOnlyPaths=</varname> creates read-only bind mounts. These | |
245 | settings may be used more than once, each usage appends to the unit's list of bind mounts. If the empty string | |
246 | is assigned to either of these two options the entire list of bind mounts defined prior to this is reset. Note | |
247 | that in this case both read-only and regular bind mounts are reset, regardless which of the two settings is | |
248 | used.</para> | |
249 | ||
250 | <para>This option is particularly useful when <varname>RootDirectory=</varname>/<varname>RootImage=</varname> | |
251 | is used. In this case the source path refers to a path on the host file system, while the destination path | |
c4d4b5a7 LP |
252 | refers to a path below the root directory of the unit.</para> |
253 | ||
db8d154d ZJS |
254 | <para>Note that the destination directory must exist or systemd must be able to create it. Thus, it |
255 | is not possible to use those options for mount points nested underneath paths specified in | |
256 | <varname>InaccessiblePaths=</varname>, or under <filename>/home/</filename> and other protected | |
257 | directories if <varname>ProtectHome=yes</varname> is | |
258 | specified. <varname>TemporaryFileSystem=</varname> with <literal>:ro</literal> or | |
259 | <varname>ProtectHome=tmpfs</varname> should be used instead.</para> | |
260 | ||
c4d4b5a7 | 261 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> |
b8afec21 LP |
262 | </varlistentry> |
263 | ||
b3d13314 LB |
264 | <varlistentry> |
265 | <term><varname>MountImages=</varname></term> | |
266 | ||
267 | <listitem><para>This setting is similar to <varname>RootImage=</varname> in that it mounts a file | |
268 | system hierarchy from a block device node or loopback file, but the destination directory can be | |
269 | specified as well as mount options. This option expects a whitespace separated list of mount | |
270 | definitions. Each definition consists of a colon-separated tuple of source path and destination | |
271 | directory. Each mount definition may be prefixed with <literal>-</literal>, in which case it will be | |
272 | ignored when its source path does not exist. The source argument is a path to a block device node or | |
273 | regular file. If source or destination contain a <literal>:</literal>, it needs to be escaped as | |
274 | <literal>\:</literal>. | |
275 | The device node or file system image file needs to follow the same rules as specified | |
276 | for <varname>RootImage=</varname>. Any mounts created with this option are specific to the unit, and | |
277 | are not visible in the host's mount table.</para> | |
278 | ||
279 | <para>These settings may be used more than once, each usage appends to the unit's list of mount | |
280 | paths. If the empty string is assigned, the entire list of mount paths defined prior to this is | |
281 | reset.</para> | |
282 | ||
283 | <para>Note that the destination directory must exist or systemd must be able to create it. Thus, it | |
284 | is not possible to use those options for mount points nested underneath paths specified in | |
285 | <varname>InaccessiblePaths=</varname>, or under <filename>/home/</filename> and other protected | |
286 | directories if <varname>ProtectHome=yes</varname> is specified.</para> | |
287 | ||
288 | <para>When <varname>DevicePolicy=</varname> is set to <literal>closed</literal> or | |
289 | <literal>strict</literal>, or set to <literal>auto</literal> and <varname>DeviceAllow=</varname> is | |
290 | set, then this setting adds <filename>/dev/loop-control</filename> with <constant>rw</constant> mode, | |
291 | <literal>block-loop</literal> and <literal>block-blkext</literal> with <constant>rwm</constant> mode | |
292 | to <varname>DeviceAllow=</varname>. See | |
293 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
294 | for the details about <varname>DevicePolicy=</varname> or <varname>DeviceAllow=</varname>. Also, see | |
295 | <varname>PrivateDevices=</varname> below, as it may change the setting of | |
296 | <varname>DevicePolicy=</varname>.</para> | |
297 | ||
298 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
299 | </varlistentry> | |
b8afec21 LP |
300 | </variablelist> |
301 | </refsect1> | |
302 | ||
303 | <refsect1> | |
304 | <title>Credentials</title> | |
305 | ||
c4d4b5a7 LP |
306 | <xi:include href="system-only.xml" xpointer="plural"/> |
307 | ||
b8afec21 LP |
308 | <variablelist class='unit-directives'> |
309 | ||
798d3a52 ZJS |
310 | <varlistentry> |
311 | <term><varname>User=</varname></term> | |
312 | <term><varname>Group=</varname></term> | |
313 | ||
29206d46 | 314 | <listitem><para>Set the UNIX user or group that the processes are executed as, respectively. Takes a single |
b8afec21 LP |
315 | user or group name, or a numeric ID as argument. For system services (services run by the system service |
316 | manager, i.e. managed by PID 1) and for user services of the root user (services managed by root's instance of | |
47da760e LP |
317 | <command>systemd --user</command>), the default is <literal>root</literal>, but <varname>User=</varname> may be |
318 | used to specify a different user. For user services of any other user, switching user identity is not | |
319 | permitted, hence the only valid setting is the same user the user's service manager is running as. If no group | |
320 | is set, the default group of the user is used. This setting does not affect commands whose command line is | |
565dab8e LP |
321 | prefixed with <literal>+</literal>.</para> |
322 | ||
887a8fa3 LP |
323 | <para>Note that this enforces only weak restrictions on the user/group name syntax, but will generate |
324 | warnings in many cases where user/group names do not adhere to the following rules: the specified | |
325 | name should consist only of the characters a-z, A-Z, 0-9, <literal>_</literal> and | |
326 | <literal>-</literal>, except for the first character which must be one of a-z, A-Z and | |
327 | <literal>_</literal> (i.e. digits and <literal>-</literal> are not permitted as first character). The | |
328 | user/group name must have at least one character, and at most 31. These restrictions are made in | |
329 | order to avoid ambiguities and to ensure user/group names and unit files remain portable among Linux | |
330 | systems. For further details on the names accepted and the names warned about see <ulink | |
331 | url="https://systemd.io/USER_NAMES">User/Group Name Syntax</ulink>.</para> | |
565dab8e LP |
332 | |
333 | <para>When used in conjunction with <varname>DynamicUser=</varname> the user/group name specified is | |
ba96a8a2 LP |
334 | dynamically allocated at the time the service is started, and released at the time the service is |
335 | stopped — unless it is already allocated statically (see below). If <varname>DynamicUser=</varname> | |
336 | is not used the specified user and group must have been created statically in the user database no | |
337 | later than the moment the service is started, for example using the | |
338 | <citerefentry><refentrytitle>sysusers.d</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
339 | facility, which is applied at boot or package install time. If the user does not exist by then | |
340 | program invocation will fail.</para> | |
b042dd68 LP |
341 | |
342 | <para>If the <varname>User=</varname> setting is used the supplementary group list is initialized | |
343 | from the specified user's default group list, as defined in the system's user and group | |
344 | database. Additional groups may be configured through the <varname>SupplementaryGroups=</varname> | |
345 | setting (see below).</para></listitem> | |
29206d46 LP |
346 | </varlistentry> |
347 | ||
348 | <varlistentry> | |
349 | <term><varname>DynamicUser=</varname></term> | |
350 | ||
c648d4d4 LP |
351 | <listitem><para>Takes a boolean parameter. If set, a UNIX user and group pair is allocated |
352 | dynamically when the unit is started, and released as soon as it is stopped. The user and group will | |
353 | not be added to <filename>/etc/passwd</filename> or <filename>/etc/group</filename>, but are managed | |
354 | transiently during runtime. The | |
355 | <citerefentry><refentrytitle>nss-systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry> glibc | |
356 | NSS module provides integration of these dynamic users/groups into the system's user and group | |
29206d46 | 357 | databases. The user and group name to use may be configured via <varname>User=</varname> and |
c648d4d4 LP |
358 | <varname>Group=</varname> (see above). If these options are not used and dynamic user/group |
359 | allocation is enabled for a unit, the name of the dynamic user/group is implicitly derived from the | |
360 | unit name. If the unit name without the type suffix qualifies as valid user name it is used directly, | |
361 | otherwise a name incorporating a hash of it is used. If a statically allocated user or group of the | |
362 | configured name already exists, it is used and no dynamic user/group is allocated. Note that if | |
363 | <varname>User=</varname> is specified and the static group with the name exists, then it is required | |
364 | that the static user with the name already exists. Similarly, if <varname>Group=</varname> is | |
365 | specified and the static user with the name exists, then it is required that the static group with | |
366 | the name already exists. Dynamic users/groups are allocated from the UID/GID range 61184…65519. It is | |
367 | recommended to avoid this range for regular system or login users. At any point in time each UID/GID | |
368 | from this range is only assigned to zero or one dynamically allocated users/groups in use. However, | |
369 | UID/GIDs are recycled after a unit is terminated. Care should be taken that any processes running as | |
370 | part of a unit for which dynamic users/groups are enabled do not leave files or directories owned by | |
371 | these users/groups around, as a different unit might get the same UID/GID assigned later on, and thus | |
372 | gain access to these files or directories. If <varname>DynamicUser=</varname> is enabled, | |
e0e65f7d LP |
373 | <varname>RemoveIPC=</varname> and <varname>PrivateTmp=</varname> are implied (and cannot be turned |
374 | off). This ensures that the lifetime of IPC objects and temporary files created by the executed | |
375 | processes is bound to the runtime of the service, and hence the lifetime of the dynamic | |
376 | user/group. Since <filename>/tmp/</filename> and <filename>/var/tmp/</filename> are usually the only | |
377 | world-writable directories on a system this ensures that a unit making use of dynamic user/group | |
378 | allocation cannot leave files around after unit termination. Furthermore | |
379 | <varname>NoNewPrivileges=</varname> and <varname>RestrictSUIDSGID=</varname> are implicitly enabled | |
380 | (and cannot be disabled), to ensure that processes invoked cannot take benefit or create SUID/SGID | |
381 | files or directories. Moreover <varname>ProtectSystem=strict</varname> and | |
c648d4d4 LP |
382 | <varname>ProtectHome=read-only</varname> are implied, thus prohibiting the service to write to |
383 | arbitrary file system locations. In order to allow the service to write to certain directories, they | |
6b000af4 | 384 | have to be allow-listed using <varname>ReadWritePaths=</varname>, but care must be taken so that |
c648d4d4 LP |
385 | UID/GID recycling doesn't create security issues involving files created by the service. Use |
386 | <varname>RuntimeDirectory=</varname> (see below) in order to assign a writable runtime directory to a | |
387 | service, owned by the dynamic user/group and removed automatically when the unit is terminated. Use | |
388 | <varname>StateDirectory=</varname>, <varname>CacheDirectory=</varname> and | |
389 | <varname>LogsDirectory=</varname> in order to assign a set of writable directories for specific | |
390 | purposes to the service in a way that they are protected from vulnerabilities due to UID reuse (see | |
391 | below). If this option is enabled, care should be taken that the unit's processes do not get access | |
392 | to directories outside of these explicitly configured and managed ones. Specifically, do not use | |
393 | <varname>BindPaths=</varname> and be careful with <constant>AF_UNIX</constant> file descriptor | |
394 | passing for directory file descriptors, as this would permit processes to create files or directories | |
de04bbdc | 395 | owned by the dynamic user/group that are not subject to the lifecycle and access guarantees of the |
c648d4d4 | 396 | service. Defaults to off.</para></listitem> |
798d3a52 ZJS |
397 | </varlistentry> |
398 | ||
399 | <varlistentry> | |
400 | <term><varname>SupplementaryGroups=</varname></term> | |
401 | ||
b8afec21 LP |
402 | <listitem><para>Sets the supplementary Unix groups the processes are executed as. This takes a space-separated |
403 | list of group names or IDs. This option may be specified more than once, in which case all listed groups are | |
404 | set as supplementary groups. When the empty string is assigned, the list of supplementary groups is reset, and | |
405 | all assignments prior to this one will have no effect. In any way, this option does not override, but extends | |
406 | the list of supplementary groups configured in the system group database for the user. This does not affect | |
407 | commands prefixed with <literal>+</literal>.</para></listitem> | |
798d3a52 ZJS |
408 | </varlistentry> |
409 | ||
00d9ef85 | 410 | <varlistentry> |
b8afec21 | 411 | <term><varname>PAMName=</varname></term> |
00d9ef85 | 412 | |
b8afec21 LP |
413 | <listitem><para>Sets the PAM service name to set up a session as. If set, the executed process will be |
414 | registered as a PAM session under the specified service name. This is only useful in conjunction with the | |
415 | <varname>User=</varname> setting, and is otherwise ignored. If not set, no PAM session will be opened for the | |
416 | executed processes. See <citerefentry | |
417 | project='man-pages'><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry> for | |
418 | details.</para> | |
00d9ef85 | 419 | |
b8afec21 LP |
420 | <para>Note that for each unit making use of this option a PAM session handler process will be maintained as |
421 | part of the unit and stays around as long as the unit is active, to ensure that appropriate actions can be | |
422 | taken when the unit and hence the PAM session terminates. This process is named <literal>(sd-pam)</literal> and | |
423 | is an immediate child process of the unit's main process.</para> | |
798d3a52 | 424 | |
b8afec21 LP |
425 | <para>Note that when this option is used for a unit it is very likely (depending on PAM configuration) that the |
426 | main unit process will be migrated to its own session scope unit when it is activated. This process will hence | |
427 | be associated with two units: the unit it was originally started from (and for which | |
428 | <varname>PAMName=</varname> was configured), and the session scope unit. Any child processes of that process | |
429 | will however be associated with the session scope unit only. This has implications when used in combination | |
430 | with <varname>NotifyAccess=</varname><option>all</option>, as these child processes will not be able to affect | |
431 | changes in the original unit through notification messages. These messages will be considered belonging to the | |
432 | session scope unit and not the original unit. It is hence not recommended to use <varname>PAMName=</varname> in | |
433 | combination with <varname>NotifyAccess=</varname><option>all</option>.</para> | |
434 | </listitem> | |
798d3a52 ZJS |
435 | </varlistentry> |
436 | ||
b8afec21 LP |
437 | </variablelist> |
438 | </refsect1> | |
798d3a52 | 439 | |
b8afec21 LP |
440 | <refsect1> |
441 | <title>Capabilities</title> | |
798d3a52 | 442 | |
c4d4b5a7 LP |
443 | <xi:include href="system-only.xml" xpointer="plural"/> |
444 | ||
b8afec21 | 445 | <variablelist class='unit-directives'> |
798d3a52 ZJS |
446 | |
447 | <varlistentry> | |
b8afec21 LP |
448 | <term><varname>CapabilityBoundingSet=</varname></term> |
449 | ||
450 | <listitem><para>Controls which capabilities to include in the capability bounding set for the executed | |
451 | process. See <citerefentry | |
452 | project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> for | |
453 | details. Takes a whitespace-separated list of capability names, e.g. <constant>CAP_SYS_ADMIN</constant>, | |
454 | <constant>CAP_DAC_OVERRIDE</constant>, <constant>CAP_SYS_PTRACE</constant>. Capabilities listed will be | |
455 | included in the bounding set, all others are removed. If the list of capabilities is prefixed with | |
456 | <literal>~</literal>, all but the listed capabilities will be included, the effect of the assignment | |
457 | inverted. Note that this option also affects the respective capabilities in the effective, permitted and | |
458 | inheritable capability sets. If this option is not used, the capability bounding set is not modified on process | |
459 | execution, hence no limits on the capabilities of the process are enforced. This option may appear more than | |
b086654c | 460 | once, in which case the bounding sets are merged by <constant>OR</constant>, or by <constant>AND</constant> if |
b8afec21 LP |
461 | the lines are prefixed with <literal>~</literal> (see below). If the empty string is assigned to this option, |
462 | the bounding set is reset to the empty capability set, and all prior settings have no effect. If set to | |
463 | <literal>~</literal> (without any further argument), the bounding set is reset to the full set of available | |
464 | capabilities, also undoing any previous settings. This does not affect commands prefixed with | |
465 | <literal>+</literal>.</para> | |
798d3a52 | 466 | |
b8afec21 LP |
467 | <para>Example: if a unit has the following, |
468 | <programlisting>CapabilityBoundingSet=CAP_A CAP_B | |
469 | CapabilityBoundingSet=CAP_B CAP_C</programlisting> | |
f8b68539 ZJS |
470 | then <constant index='false'>CAP_A</constant>, <constant index='false'>CAP_B</constant>, and |
471 | <constant index='false'>CAP_C</constant> are set. If the second line is prefixed with | |
472 | <literal>~</literal>, e.g., | |
b8afec21 LP |
473 | <programlisting>CapabilityBoundingSet=CAP_A CAP_B |
474 | CapabilityBoundingSet=~CAP_B CAP_C</programlisting> | |
f8b68539 | 475 | then, only <constant index='false'>CAP_A</constant> is set.</para></listitem> |
798d3a52 ZJS |
476 | </varlistentry> |
477 | ||
478 | <varlistentry> | |
b8afec21 | 479 | <term><varname>AmbientCapabilities=</varname></term> |
798d3a52 | 480 | |
b8afec21 LP |
481 | <listitem><para>Controls which capabilities to include in the ambient capability set for the executed |
482 | process. Takes a whitespace-separated list of capability names, e.g. <constant>CAP_SYS_ADMIN</constant>, | |
483 | <constant>CAP_DAC_OVERRIDE</constant>, <constant>CAP_SYS_PTRACE</constant>. This option may appear more than | |
484 | once in which case the ambient capability sets are merged (see the above examples in | |
485 | <varname>CapabilityBoundingSet=</varname>). If the list of capabilities is prefixed with <literal>~</literal>, | |
486 | all but the listed capabilities will be included, the effect of the assignment inverted. If the empty string is | |
487 | assigned to this option, the ambient capability set is reset to the empty capability set, and all prior | |
488 | settings have no effect. If set to <literal>~</literal> (without any further argument), the ambient capability | |
489 | set is reset to the full set of available capabilities, also undoing any previous settings. Note that adding | |
490 | capabilities to ambient capability set adds them to the process's inherited capability set. </para><para> | |
491 | Ambient capability sets are useful if you want to execute a process as a non-privileged user but still want to | |
492 | give it some capabilities. Note that in this case option <constant>keep-caps</constant> is automatically added | |
493 | to <varname>SecureBits=</varname> to retain the capabilities over the user | |
494 | change. <varname>AmbientCapabilities=</varname> does not affect commands prefixed with | |
495 | <literal>+</literal>.</para></listitem> | |
798d3a52 ZJS |
496 | </varlistentry> |
497 | ||
b8afec21 LP |
498 | </variablelist> |
499 | </refsect1> | |
798d3a52 | 500 | |
b8afec21 LP |
501 | <refsect1> |
502 | <title>Security</title> | |
798d3a52 | 503 | |
b8afec21 | 504 | <variablelist class='unit-directives'> |
798d3a52 ZJS |
505 | |
506 | <varlistentry> | |
b8afec21 | 507 | <term><varname>NoNewPrivileges=</varname></term> |
798d3a52 | 508 | |
7445db6e LP |
509 | <listitem><para>Takes a boolean argument. If true, ensures that the service process and all its |
510 | children can never gain new privileges through <function>execve()</function> (e.g. via setuid or | |
511 | setgid bits, or filesystem capabilities). This is the simplest and most effective way to ensure that | |
512 | a process and its children can never elevate privileges again. Defaults to false, but certain | |
513 | settings override this and ignore the value of this setting. This is the case when | |
514 | <varname>SystemCallFilter=</varname>, <varname>SystemCallArchitectures=</varname>, | |
515 | <varname>RestrictAddressFamilies=</varname>, <varname>RestrictNamespaces=</varname>, | |
516 | <varname>PrivateDevices=</varname>, <varname>ProtectKernelTunables=</varname>, | |
d916e35b | 517 | <varname>ProtectKernelModules=</varname>, <varname>ProtectKernelLogs=</varname>, |
022d3345 KK |
518 | <varname>ProtectClock=</varname>, <varname>MemoryDenyWriteExecute=</varname>, |
519 | <varname>RestrictRealtime=</varname>, <varname>RestrictSUIDSGID=</varname>, <varname>DynamicUser=</varname> | |
520 | or <varname>LockPersonality=</varname> are specified. Note that even if this setting is overridden by them, | |
521 | <command>systemctl show</command> shows the original value of this setting. | |
522 | Also see <ulink url="https://www.kernel.org/doc/html/latest/userspace-api/no_new_privs.html">No New Privileges | |
bf65b7e0 | 523 | Flag</ulink>.</para></listitem> |
798d3a52 ZJS |
524 | </varlistentry> |
525 | ||
526 | <varlistentry> | |
b8afec21 | 527 | <term><varname>SecureBits=</varname></term> |
798d3a52 | 528 | |
b8afec21 LP |
529 | <listitem><para>Controls the secure bits set for the executed process. Takes a space-separated combination of |
530 | options from the following list: <option>keep-caps</option>, <option>keep-caps-locked</option>, | |
531 | <option>no-setuid-fixup</option>, <option>no-setuid-fixup-locked</option>, <option>noroot</option>, and | |
532 | <option>noroot-locked</option>. This option may appear more than once, in which case the secure bits are | |
533 | ORed. If the empty string is assigned to this option, the bits are reset to 0. This does not affect commands | |
534 | prefixed with <literal>+</literal>. See <citerefentry | |
535 | project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> for | |
536 | details.</para></listitem> | |
798d3a52 ZJS |
537 | </varlistentry> |
538 | ||
b8afec21 LP |
539 | </variablelist> |
540 | </refsect1> | |
798d3a52 | 541 | |
b8afec21 LP |
542 | <refsect1> |
543 | <title>Mandatory Access Control</title> | |
c4d4b5a7 LP |
544 | |
545 | <xi:include href="system-only.xml" xpointer="plural"/> | |
546 | ||
e0e2ecd5 | 547 | <variablelist class='unit-directives'> |
798d3a52 | 548 | |
798d3a52 | 549 | <varlistentry> |
b8afec21 LP |
550 | <term><varname>SELinuxContext=</varname></term> |
551 | ||
552 | <listitem><para>Set the SELinux security context of the executed process. If set, this will override the | |
553 | automated domain transition. However, the policy still needs to authorize the transition. This directive is | |
554 | ignored if SELinux is disabled. If prefixed by <literal>-</literal>, all errors will be ignored. This does not | |
555 | affect commands prefixed with <literal>+</literal>. See <citerefentry | |
556 | project='die-net'><refentrytitle>setexeccon</refentrytitle><manvolnum>3</manvolnum></citerefentry> for | |
557 | details.</para></listitem> | |
798d3a52 ZJS |
558 | </varlistentry> |
559 | ||
b4c14404 | 560 | <varlistentry> |
b8afec21 | 561 | <term><varname>AppArmorProfile=</varname></term> |
b4c14404 | 562 | |
e9dd6984 ZJS |
563 | <listitem><para>Takes a profile name as argument. The process executed by the unit will switch to |
564 | this profile when started. Profiles must already be loaded in the kernel, or the unit will fail. If | |
565 | prefixed by <literal>-</literal>, all errors will be ignored. This setting has no effect if AppArmor | |
566 | is not enabled. This setting not affect commands prefixed with <literal>+</literal>.</para> | |
567 | </listitem> | |
b8afec21 | 568 | </varlistentry> |
00819cc1 | 569 | |
b8afec21 LP |
570 | <varlistentry> |
571 | <term><varname>SmackProcessLabel=</varname></term> | |
b4c14404 | 572 | |
b8afec21 LP |
573 | <listitem><para>Takes a <option>SMACK64</option> security label as argument. The process executed by the unit |
574 | will be started under this label and SMACK will decide whether the process is allowed to run or not, based on | |
575 | it. The process will continue to run under the label specified here unless the executable has its own | |
576 | <option>SMACK64EXEC</option> label, in which case the process will transition to run under that label. When not | |
577 | specified, the label that systemd is running under is used. This directive is ignored if SMACK is | |
578 | disabled.</para> | |
b4c14404 | 579 | |
b8afec21 LP |
580 | <para>The value may be prefixed by <literal>-</literal>, in which case all errors will be ignored. An empty |
581 | value may be specified to unset previous assignments. This does not affect commands prefixed with | |
582 | <literal>+</literal>.</para></listitem> | |
b4c14404 FB |
583 | </varlistentry> |
584 | ||
b8afec21 LP |
585 | </variablelist> |
586 | </refsect1> | |
00819cc1 | 587 | |
b8afec21 LP |
588 | <refsect1> |
589 | <title>Process Properties</title> | |
00819cc1 | 590 | |
e0e2ecd5 | 591 | <variablelist class='unit-directives'> |
00819cc1 | 592 | |
798d3a52 | 593 | <varlistentry> |
b8afec21 LP |
594 | <term><varname>LimitCPU=</varname></term> |
595 | <term><varname>LimitFSIZE=</varname></term> | |
596 | <term><varname>LimitDATA=</varname></term> | |
597 | <term><varname>LimitSTACK=</varname></term> | |
598 | <term><varname>LimitCORE=</varname></term> | |
599 | <term><varname>LimitRSS=</varname></term> | |
600 | <term><varname>LimitNOFILE=</varname></term> | |
601 | <term><varname>LimitAS=</varname></term> | |
602 | <term><varname>LimitNPROC=</varname></term> | |
603 | <term><varname>LimitMEMLOCK=</varname></term> | |
604 | <term><varname>LimitLOCKS=</varname></term> | |
605 | <term><varname>LimitSIGPENDING=</varname></term> | |
606 | <term><varname>LimitMSGQUEUE=</varname></term> | |
607 | <term><varname>LimitNICE=</varname></term> | |
608 | <term><varname>LimitRTPRIO=</varname></term> | |
609 | <term><varname>LimitRTTIME=</varname></term> | |
fc8d0381 | 610 | |
b8afec21 | 611 | <listitem><para>Set soft and hard limits on various resources for executed processes. See |
54ed193f LP |
612 | <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry> for |
613 | details on the resource limit concept. Resource limits may be specified in two formats: either as | |
614 | single value to set a specific soft and hard limit to the same value, or as colon-separated pair | |
615 | <option>soft:hard</option> to set both limits individually (e.g. <literal>LimitAS=4G:16G</literal>). | |
616 | Use the string <option>infinity</option> to configure no limit on a specific resource. The | |
617 | multiplicative suffixes K, M, G, T, P and E (to the base 1024) may be used for resource limits | |
618 | measured in bytes (e.g. <literal>LimitAS=16G</literal>). For the limits referring to time values, the | |
619 | usual time units ms, s, min, h and so on may be used (see | |
b8afec21 | 620 | <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry> for |
54ed193f LP |
621 | details). Note that if no time unit is specified for <varname>LimitCPU=</varname> the default unit of |
622 | seconds is implied, while for <varname>LimitRTTIME=</varname> the default unit of microseconds is | |
623 | implied. Also, note that the effective granularity of the limits might influence their | |
624 | enforcement. For example, time limits specified for <varname>LimitCPU=</varname> will be rounded up | |
625 | implicitly to multiples of 1s. For <varname>LimitNICE=</varname> the value may be specified in two | |
626 | syntaxes: if prefixed with <literal>+</literal> or <literal>-</literal>, the value is understood as | |
627 | regular Linux nice value in the range -20..19. If not prefixed like this the value is understood as | |
628 | raw resource limit parameter in the range 0..40 (with 0 being equivalent to 1).</para> | |
629 | ||
630 | <para>Note that most process resource limits configured with these options are per-process, and | |
631 | processes may fork in order to acquire a new set of resources that are accounted independently of the | |
632 | original process, and may thus escape limits set. Also note that <varname>LimitRSS=</varname> is not | |
633 | implemented on Linux, and setting it has no effect. Often it is advisable to prefer the resource | |
634 | controls listed in | |
b8afec21 | 635 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
54ed193f LP |
636 | over these per-process limits, as they apply to services as a whole, may be altered dynamically at |
637 | runtime, and are generally more expressive. For example, <varname>MemoryMax=</varname> is a more | |
638 | powerful (and working) replacement for <varname>LimitRSS=</varname>.</para> | |
fc8d0381 | 639 | |
b8afec21 LP |
640 | <para>Resource limits not configured explicitly for a unit default to the value configured in the various |
641 | <varname>DefaultLimitCPU=</varname>, <varname>DefaultLimitFSIZE=</varname>, … options available in | |
642 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, and – | |
643 | if not configured there – the kernel or per-user defaults, as defined by the OS (the latter only for user | |
54ed193f LP |
644 | services, see below).</para> |
645 | ||
646 | <para>For system units these resource limits may be chosen freely. When these settings are configured | |
647 | in a user service (i.e. a service run by the per-user instance of the service manager) they cannot be | |
648 | used to raise the limits above those set for the user manager itself when it was first invoked, as | |
649 | the user's service manager generally lacks the privileges to do so. In user context these | |
650 | configuration options are hence only useful to lower the limits passed in or to raise the soft limit | |
651 | to the maximum of the hard limit as configured for the user. To raise the user's limits further, the | |
652 | available configuration mechanisms differ between operating systems, but typically require | |
653 | privileges. In most cases it is possible to configure higher per-user resource limits via PAM or by | |
654 | setting limits on the system service encapsulating the user's service manager, i.e. the user's | |
655 | instance of <filename>user@.service</filename>. After making such changes, make sure to restart the | |
656 | user's service manager.</para> | |
fc8d0381 | 657 | |
b8afec21 LP |
658 | <table> |
659 | <title>Resource limit directives, their equivalent <command>ulimit</command> shell commands and the unit used</title> | |
798d3a52 | 660 | |
a4c18002 | 661 | <tgroup cols='3'> |
798d3a52 ZJS |
662 | <colspec colname='directive' /> |
663 | <colspec colname='equivalent' /> | |
a4c18002 | 664 | <colspec colname='unit' /> |
798d3a52 ZJS |
665 | <thead> |
666 | <row> | |
667 | <entry>Directive</entry> | |
f4c9356d | 668 | <entry><command>ulimit</command> equivalent</entry> |
a4c18002 | 669 | <entry>Unit</entry> |
798d3a52 ZJS |
670 | </row> |
671 | </thead> | |
672 | <tbody> | |
673 | <row> | |
a4c18002 | 674 | <entry>LimitCPU=</entry> |
798d3a52 | 675 | <entry>ulimit -t</entry> |
a4c18002 | 676 | <entry>Seconds</entry> |
798d3a52 ZJS |
677 | </row> |
678 | <row> | |
a4c18002 | 679 | <entry>LimitFSIZE=</entry> |
798d3a52 | 680 | <entry>ulimit -f</entry> |
a4c18002 | 681 | <entry>Bytes</entry> |
798d3a52 ZJS |
682 | </row> |
683 | <row> | |
a4c18002 | 684 | <entry>LimitDATA=</entry> |
798d3a52 | 685 | <entry>ulimit -d</entry> |
a4c18002 | 686 | <entry>Bytes</entry> |
798d3a52 ZJS |
687 | </row> |
688 | <row> | |
a4c18002 | 689 | <entry>LimitSTACK=</entry> |
798d3a52 | 690 | <entry>ulimit -s</entry> |
a4c18002 | 691 | <entry>Bytes</entry> |
798d3a52 ZJS |
692 | </row> |
693 | <row> | |
a4c18002 | 694 | <entry>LimitCORE=</entry> |
798d3a52 | 695 | <entry>ulimit -c</entry> |
a4c18002 | 696 | <entry>Bytes</entry> |
798d3a52 ZJS |
697 | </row> |
698 | <row> | |
a4c18002 | 699 | <entry>LimitRSS=</entry> |
798d3a52 | 700 | <entry>ulimit -m</entry> |
a4c18002 | 701 | <entry>Bytes</entry> |
798d3a52 ZJS |
702 | </row> |
703 | <row> | |
a4c18002 | 704 | <entry>LimitNOFILE=</entry> |
798d3a52 | 705 | <entry>ulimit -n</entry> |
a4c18002 | 706 | <entry>Number of File Descriptors</entry> |
798d3a52 ZJS |
707 | </row> |
708 | <row> | |
a4c18002 | 709 | <entry>LimitAS=</entry> |
798d3a52 | 710 | <entry>ulimit -v</entry> |
a4c18002 | 711 | <entry>Bytes</entry> |
798d3a52 ZJS |
712 | </row> |
713 | <row> | |
a4c18002 | 714 | <entry>LimitNPROC=</entry> |
798d3a52 | 715 | <entry>ulimit -u</entry> |
a4c18002 | 716 | <entry>Number of Processes</entry> |
798d3a52 ZJS |
717 | </row> |
718 | <row> | |
a4c18002 | 719 | <entry>LimitMEMLOCK=</entry> |
798d3a52 | 720 | <entry>ulimit -l</entry> |
a4c18002 | 721 | <entry>Bytes</entry> |
798d3a52 ZJS |
722 | </row> |
723 | <row> | |
a4c18002 | 724 | <entry>LimitLOCKS=</entry> |
798d3a52 | 725 | <entry>ulimit -x</entry> |
a4c18002 | 726 | <entry>Number of Locks</entry> |
798d3a52 ZJS |
727 | </row> |
728 | <row> | |
a4c18002 | 729 | <entry>LimitSIGPENDING=</entry> |
798d3a52 | 730 | <entry>ulimit -i</entry> |
a4c18002 | 731 | <entry>Number of Queued Signals</entry> |
798d3a52 ZJS |
732 | </row> |
733 | <row> | |
a4c18002 | 734 | <entry>LimitMSGQUEUE=</entry> |
798d3a52 | 735 | <entry>ulimit -q</entry> |
a4c18002 | 736 | <entry>Bytes</entry> |
798d3a52 ZJS |
737 | </row> |
738 | <row> | |
a4c18002 | 739 | <entry>LimitNICE=</entry> |
798d3a52 | 740 | <entry>ulimit -e</entry> |
a4c18002 | 741 | <entry>Nice Level</entry> |
798d3a52 ZJS |
742 | </row> |
743 | <row> | |
a4c18002 | 744 | <entry>LimitRTPRIO=</entry> |
798d3a52 | 745 | <entry>ulimit -r</entry> |
a4c18002 | 746 | <entry>Realtime Priority</entry> |
798d3a52 ZJS |
747 | </row> |
748 | <row> | |
a4c18002 | 749 | <entry>LimitRTTIME=</entry> |
798d3a52 | 750 | <entry>No equivalent</entry> |
a4c18002 | 751 | <entry>Microseconds</entry> |
798d3a52 ZJS |
752 | </row> |
753 | </tbody> | |
754 | </tgroup> | |
a4c18002 | 755 | </table></listitem> |
798d3a52 ZJS |
756 | </varlistentry> |
757 | ||
758 | <varlistentry> | |
b8afec21 | 759 | <term><varname>UMask=</varname></term> |
9eb484fa | 760 | |
b8afec21 | 761 | <listitem><para>Controls the file mode creation mask. Takes an access mode in octal notation. See |
5e37d193 FB |
762 | <citerefentry><refentrytitle>umask</refentrytitle><manvolnum>2</manvolnum></citerefentry> for |
763 | details. Defaults to 0022 for system units. For units of the user service manager the default value | |
764 | is inherited from the user instance (whose default is inherited from the system service manager, and | |
765 | thus also is 0022). Hence changing the default value of a user instance, either via | |
766 | <varname>UMask=</varname> or via a PAM module, will affect the user instance itself and all user | |
767 | units started by the user instance unless a user unit has specified its own | |
768 | <varname>UMask=</varname>.</para></listitem> | |
b8afec21 LP |
769 | </varlistentry> |
770 | ||
ad21e542 ZJS |
771 | <varlistentry> |
772 | <term><varname>CoredumpFilter=</varname></term> | |
773 | ||
774 | <listitem><para>Controls which types of memory mappings will be saved if the process dumps core | |
775 | (using the <filename>/proc/<replaceable>pid</replaceable>/coredump_filter</filename> file). Takes a | |
776 | whitespace-separated combination of mapping type names or numbers (with the default base 16). Mapping | |
777 | type names are <constant>private-anonymous</constant>, <constant>shared-anonymous</constant>, | |
778 | <constant>private-file-backed</constant>, <constant>shared-file-backed</constant>, | |
779 | <constant>elf-headers</constant>, <constant>private-huge</constant>, | |
780 | <constant>shared-huge</constant>, <constant>private-dax</constant>, <constant>shared-dax</constant>, | |
781 | and the special values <constant>all</constant> (all types) and <constant>default</constant> (the | |
782 | kernel default of <literal><constant>private-anonymous</constant> | |
783 | <constant>shared-anonymous</constant> <constant>elf-headers</constant> | |
784 | <constant>private-huge</constant></literal>). See | |
b7a47345 ZJS |
785 | <citerefentry project='man-pages'><refentrytitle>core</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
786 | for the meaning of the mapping types. When specified multiple times, all specified masks are | |
787 | ORed. When not set, or if the empty value is assigned, the inherited value is not changed.</para> | |
ad21e542 ZJS |
788 | |
789 | <example> | |
790 | <title>Add DAX pages to the dump filter</title> | |
791 | ||
792 | <programlisting>CoredumpFilter=default private-dax shared-dax</programlisting> | |
793 | </example> | |
794 | </listitem> | |
795 | </varlistentry> | |
796 | ||
b8afec21 LP |
797 | <varlistentry> |
798 | <term><varname>KeyringMode=</varname></term> | |
799 | ||
800 | <listitem><para>Controls how the kernel session keyring is set up for the service (see <citerefentry | |
801 | project='man-pages'><refentrytitle>session-keyring</refentrytitle><manvolnum>7</manvolnum></citerefentry> for | |
802 | details on the session keyring). Takes one of <option>inherit</option>, <option>private</option>, | |
803 | <option>shared</option>. If set to <option>inherit</option> no special keyring setup is done, and the kernel's | |
804 | default behaviour is applied. If <option>private</option> is used a new session keyring is allocated when a | |
805 | service process is invoked, and it is not linked up with any user keyring. This is the recommended setting for | |
806 | system services, as this ensures that multiple services running under the same system user ID (in particular | |
807 | the root user) do not share their key material among each other. If <option>shared</option> is used a new | |
808 | session keyring is allocated as for <option>private</option>, but the user keyring of the user configured with | |
809 | <varname>User=</varname> is linked into it, so that keys assigned to the user may be requested by the unit's | |
810 | processes. In this modes multiple units running processes under the same user ID may share key material. Unless | |
811 | <option>inherit</option> is selected the unique invocation ID for the unit (see below) is added as a protected | |
812 | key by the name <literal>invocation_id</literal> to the newly created session keyring. Defaults to | |
00f5ad93 LP |
813 | <option>private</option> for services of the system service manager and to <option>inherit</option> for |
814 | non-service units and for services of the user service manager.</para></listitem> | |
b8afec21 LP |
815 | </varlistentry> |
816 | ||
817 | <varlistentry> | |
818 | <term><varname>OOMScoreAdjust=</varname></term> | |
819 | ||
8e74bf7f LP |
820 | <listitem><para>Sets the adjustment value for the Linux kernel's Out-Of-Memory (OOM) killer score for |
821 | executed processes. Takes an integer between -1000 (to disable OOM killing of processes of this unit) | |
822 | and 1000 (to make killing of processes of this unit under memory pressure very likely). See <ulink | |
823 | url="https://www.kernel.org/doc/Documentation/filesystems/proc.txt">proc.txt</ulink> for details. If | |
824 | not specified defaults to the OOM score adjustment level of the service manager itself, which is | |
825 | normally at 0.</para> | |
826 | ||
827 | <para>Use the <varname>OOMPolicy=</varname> setting of service units to configure how the service | |
828 | manager shall react to the kernel OOM killer terminating a process of the service. See | |
829 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
830 | for details.</para></listitem> | |
b8afec21 LP |
831 | </varlistentry> |
832 | ||
833 | <varlistentry> | |
834 | <term><varname>TimerSlackNSec=</varname></term> | |
835 | <listitem><para>Sets the timer slack in nanoseconds for the executed processes. The timer slack controls the | |
836 | accuracy of wake-ups triggered by timers. See | |
837 | <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry> for more | |
838 | information. Note that in contrast to most other time span definitions this parameter takes an integer value in | |
839 | nano-seconds if no unit is specified. The usual time units are understood too.</para></listitem> | |
840 | </varlistentry> | |
841 | ||
842 | <varlistentry> | |
843 | <term><varname>Personality=</varname></term> | |
844 | ||
845 | <listitem><para>Controls which kernel architecture <citerefentry | |
846 | project='man-pages'><refentrytitle>uname</refentrytitle><manvolnum>2</manvolnum></citerefentry> shall report, | |
847 | when invoked by unit processes. Takes one of the architecture identifiers <constant>x86</constant>, | |
848 | <constant>x86-64</constant>, <constant>ppc</constant>, <constant>ppc-le</constant>, <constant>ppc64</constant>, | |
849 | <constant>ppc64-le</constant>, <constant>s390</constant> or <constant>s390x</constant>. Which personality | |
850 | architectures are supported depends on the system architecture. Usually the 64bit versions of the various | |
851 | system architectures support their immediate 32bit personality architecture counterpart, but no others. For | |
852 | example, <constant>x86-64</constant> systems support the <constant>x86-64</constant> and | |
853 | <constant>x86</constant> personalities but no others. The personality feature is useful when running 32-bit | |
854 | services on a 64-bit host system. If not specified, the personality is left unmodified and thus reflects the | |
855 | personality of the host system's kernel.</para></listitem> | |
856 | </varlistentry> | |
857 | ||
858 | <varlistentry> | |
859 | <term><varname>IgnoreSIGPIPE=</varname></term> | |
860 | ||
861 | <listitem><para>Takes a boolean argument. If true, causes <constant>SIGPIPE</constant> to be ignored in the | |
862 | executed process. Defaults to true because <constant>SIGPIPE</constant> generally is useful only in shell | |
863 | pipelines.</para></listitem> | |
864 | </varlistentry> | |
865 | ||
866 | </variablelist> | |
867 | </refsect1> | |
868 | ||
869 | <refsect1> | |
870 | <title>Scheduling</title> | |
871 | ||
e0e2ecd5 | 872 | <variablelist class='unit-directives'> |
b8afec21 LP |
873 | |
874 | <varlistentry> | |
875 | <term><varname>Nice=</varname></term> | |
876 | ||
877 | <listitem><para>Sets the default nice level (scheduling priority) for executed processes. Takes an integer | |
878 | between -20 (highest priority) and 19 (lowest priority). See | |
879 | <citerefentry><refentrytitle>setpriority</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
880 | details.</para></listitem> | |
881 | </varlistentry> | |
882 | ||
883 | <varlistentry> | |
884 | <term><varname>CPUSchedulingPolicy=</varname></term> | |
885 | ||
886 | <listitem><para>Sets the CPU scheduling policy for executed processes. Takes one of <option>other</option>, | |
887 | <option>batch</option>, <option>idle</option>, <option>fifo</option> or <option>rr</option>. See | |
888 | <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
889 | details.</para></listitem> | |
890 | </varlistentry> | |
891 | ||
892 | <varlistentry> | |
893 | <term><varname>CPUSchedulingPriority=</varname></term> | |
894 | ||
895 | <listitem><para>Sets the CPU scheduling priority for executed processes. The available priority range depends | |
896 | on the selected CPU scheduling policy (see above). For real-time scheduling policies an integer between 1 | |
897 | (lowest priority) and 99 (highest priority) can be used. See | |
898 | <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
899 | details. </para></listitem> | |
900 | </varlistentry> | |
901 | ||
902 | <varlistentry> | |
903 | <term><varname>CPUSchedulingResetOnFork=</varname></term> | |
904 | ||
905 | <listitem><para>Takes a boolean argument. If true, elevated CPU scheduling priorities and policies will be | |
906 | reset when the executed processes fork, and can hence not leak into child processes. See | |
907 | <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
908 | details. Defaults to false.</para></listitem> | |
909 | </varlistentry> | |
910 | ||
911 | <varlistentry> | |
912 | <term><varname>CPUAffinity=</varname></term> | |
913 | ||
914 | <listitem><para>Controls the CPU affinity of the executed processes. Takes a list of CPU indices or ranges | |
e2b2fb7f MS |
915 | separated by either whitespace or commas. Alternatively, takes a special "numa" value in which case systemd |
916 | automatically derives allowed CPU range based on the value of <varname>NUMAMask=</varname> option. CPU ranges | |
917 | are specified by the lower and upper CPU indices separated by a dash. This option may be specified more than | |
918 | once, in which case the specified CPU affinity masks are merged. If the empty string is assigned, the mask | |
919 | is reset, all assignments prior to this will have no effect. See | |
b8afec21 LP |
920 | <citerefentry><refentrytitle>sched_setaffinity</refentrytitle><manvolnum>2</manvolnum></citerefentry> for |
921 | details.</para></listitem> | |
922 | </varlistentry> | |
923 | ||
b070c7c0 MS |
924 | <varlistentry> |
925 | <term><varname>NUMAPolicy=</varname></term> | |
926 | ||
927 | <listitem><para>Controls the NUMA memory policy of the executed processes. Takes a policy type, one of: | |
928 | <option>default</option>, <option>preferred</option>, <option>bind</option>, <option>interleave</option> and | |
929 | <option>local</option>. A list of NUMA nodes that should be associated with the policy must be specified | |
930 | in <varname>NUMAMask=</varname>. For more details on each policy please see, | |
931 | <citerefentry><refentrytitle>set_mempolicy</refentrytitle><manvolnum>2</manvolnum></citerefentry>. For overall | |
932 | overview of NUMA support in Linux see, | |
e9dd6984 | 933 | <citerefentry project='man-pages'><refentrytitle>numa</refentrytitle><manvolnum>7</manvolnum></citerefentry>. |
b070c7c0 MS |
934 | </para></listitem> |
935 | </varlistentry> | |
936 | ||
937 | <varlistentry> | |
938 | <term><varname>NUMAMask=</varname></term> | |
939 | ||
940 | <listitem><para>Controls the NUMA node list which will be applied alongside with selected NUMA policy. | |
941 | Takes a list of NUMA nodes and has the same syntax as a list of CPUs for <varname>CPUAffinity=</varname> | |
942 | option. Note that the list of NUMA nodes is not required for <option>default</option> and <option>local</option> | |
943 | policies and for <option>preferred</option> policy we expect a single NUMA node.</para></listitem> | |
944 | </varlistentry> | |
945 | ||
b8afec21 LP |
946 | <varlistentry> |
947 | <term><varname>IOSchedulingClass=</varname></term> | |
948 | ||
949 | <listitem><para>Sets the I/O scheduling class for executed processes. Takes an integer between 0 and 3 or one | |
950 | of the strings <option>none</option>, <option>realtime</option>, <option>best-effort</option> or | |
617d253a YW |
951 | <option>idle</option>. If the empty string is assigned to this option, all prior assignments to both |
952 | <varname>IOSchedulingClass=</varname> and <varname>IOSchedulingPriority=</varname> have no effect. See | |
b8afec21 LP |
953 | <citerefentry><refentrytitle>ioprio_set</refentrytitle><manvolnum>2</manvolnum></citerefentry> for |
954 | details.</para></listitem> | |
955 | </varlistentry> | |
956 | ||
957 | <varlistentry> | |
958 | <term><varname>IOSchedulingPriority=</varname></term> | |
959 | ||
960 | <listitem><para>Sets the I/O scheduling priority for executed processes. Takes an integer between 0 (highest | |
961 | priority) and 7 (lowest priority). The available priorities depend on the selected I/O scheduling class (see | |
617d253a YW |
962 | above). If the empty string is assigned to this option, all prior assignments to both |
963 | <varname>IOSchedulingClass=</varname> and <varname>IOSchedulingPriority=</varname> have no effect. | |
964 | See <citerefentry><refentrytitle>ioprio_set</refentrytitle><manvolnum>2</manvolnum></citerefentry> for | |
b8afec21 LP |
965 | details.</para></listitem> |
966 | </varlistentry> | |
967 | ||
968 | </variablelist> | |
969 | </refsect1> | |
970 | ||
b8afec21 LP |
971 | <refsect1> |
972 | <title>Sandboxing</title> | |
973 | ||
2d2224e4 LP |
974 | <para>The following sandboxing options are an effective way to limit the exposure of the system towards the unit's |
975 | processes. It is recommended to turn on as many of these options for each unit as is possible without negatively | |
976 | affecting the process' ability to operate. Note that many of these sandboxing features are gracefully turned off on | |
977 | systems where the underlying security mechanism is not available. For example, <varname>ProtectSystem=</varname> | |
978 | has no effect if the kernel is built without file system namespacing or if the service manager runs in a container | |
979 | manager that makes file system namespacing unavailable to its payload. Similar, | |
980 | <varname>RestrictRealtime=</varname> has no effect on systems that lack support for SECCOMP system call filtering, | |
981 | or in containers where support for this is turned off.</para> | |
982 | ||
d287820d LP |
983 | <para>Also note that some sandboxing functionality is generally not available in user services (i.e. services run |
984 | by the per-user service manager). Specifically, the various settings requiring file system namespacing support | |
985 | (such as <varname>ProtectSystem=</varname>) are not available, as the underlying kernel functionality is only | |
5749f855 AZ |
986 | accessible to privileged processes. However, most namespacing settings, that will not work on their own in user |
987 | services, will work when used in conjunction with <varname>PrivateUsers=</varname><option>true</option>.</para> | |
d287820d | 988 | |
e0e2ecd5 | 989 | <variablelist class='unit-directives'> |
b8afec21 LP |
990 | |
991 | <varlistentry> | |
992 | <term><varname>ProtectSystem=</varname></term> | |
993 | ||
994 | <listitem><para>Takes a boolean argument or the special values <literal>full</literal> or | |
26b81908 ZJS |
995 | <literal>strict</literal>. If true, mounts the <filename>/usr</filename> and the boot loader |
996 | directories (<filename>/boot</filename> and <filename>/efi</filename>) read-only for processes | |
997 | invoked by this unit. If set to <literal>full</literal>, the <filename>/etc</filename> directory is | |
998 | mounted read-only, too. If set to <literal>strict</literal> the entire file system hierarchy is | |
999 | mounted read-only, except for the API file system subtrees <filename>/dev</filename>, | |
b8afec21 LP |
1000 | <filename>/proc</filename> and <filename>/sys</filename> (protect these directories using |
1001 | <varname>PrivateDevices=</varname>, <varname>ProtectKernelTunables=</varname>, | |
1002 | <varname>ProtectControlGroups=</varname>). This setting ensures that any modification of the vendor-supplied | |
1003 | operating system (and optionally its configuration, and local mounts) is prohibited for the service. It is | |
1004 | recommended to enable this setting for all long-running services, unless they are involved with system updates | |
1005 | or need to modify the operating system in other ways. If this option is used, | |
1006 | <varname>ReadWritePaths=</varname> may be used to exclude specific directories from being made read-only. This | |
0e18724e LP |
1007 | setting is implied if <varname>DynamicUser=</varname> is set. This setting cannot ensure protection in all |
1008 | cases. In general it has the same limitations as <varname>ReadOnlyPaths=</varname>, see below. Defaults to | |
1009 | off.</para></listitem> | |
b8afec21 LP |
1010 | </varlistentry> |
1011 | ||
1012 | <varlistentry> | |
1013 | <term><varname>ProtectHome=</varname></term> | |
1014 | ||
e4da7d8c | 1015 | <listitem><para>Takes a boolean argument or the special values <literal>read-only</literal> or |
db8d154d ZJS |
1016 | <literal>tmpfs</literal>. If true, the directories <filename>/home</filename>, |
1017 | <filename>/root</filename>, and <filename>/run/user</filename> are made inaccessible and empty for | |
1018 | processes invoked by this unit. If set to <literal>read-only</literal>, the three directories are | |
1019 | made read-only instead. If set to <literal>tmpfs</literal>, temporary file systems are mounted on the | |
1020 | three directories in read-only mode. The value <literal>tmpfs</literal> is useful to hide home | |
1021 | directories not relevant to the processes invoked by the unit, while still allowing necessary | |
1022 | directories to be made visible when listed in <varname>BindPaths=</varname> or | |
1023 | <varname>BindReadOnlyPaths=</varname>.</para> | |
e4da7d8c YW |
1024 | |
1025 | <para>Setting this to <literal>yes</literal> is mostly equivalent to set the three directories in | |
1b2ad5d9 | 1026 | <varname>InaccessiblePaths=</varname>. Similarly, <literal>read-only</literal> is mostly equivalent to |
e4da7d8c | 1027 | <varname>ReadOnlyPaths=</varname>, and <literal>tmpfs</literal> is mostly equivalent to |
db8d154d | 1028 | <varname>TemporaryFileSystem=</varname> with <literal>:ro</literal>.</para> |
e4da7d8c | 1029 | |
db8d154d ZJS |
1030 | <para>It is recommended to enable this setting for all long-running services (in particular |
1031 | network-facing ones), to ensure they cannot get access to private user data, unless the services | |
1032 | actually require access to the user's private data. This setting is implied if | |
1033 | <varname>DynamicUser=</varname> is set. This setting cannot ensure protection in all cases. In | |
1034 | general it has the same limitations as <varname>ReadOnlyPaths=</varname>, see below.</para> | |
c4d4b5a7 LP |
1035 | |
1036 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
b8afec21 LP |
1037 | </varlistentry> |
1038 | ||
1039 | <varlistentry> | |
1040 | <term><varname>RuntimeDirectory=</varname></term> | |
1041 | <term><varname>StateDirectory=</varname></term> | |
1042 | <term><varname>CacheDirectory=</varname></term> | |
1043 | <term><varname>LogsDirectory=</varname></term> | |
1044 | <term><varname>ConfigurationDirectory=</varname></term> | |
1045 | ||
1046 | <listitem><para>These options take a whitespace-separated list of directory names. The specified directory | |
d3c8afd0 | 1047 | names must be relative, and may not include <literal>..</literal>. If set, one or more |
8d00da49 | 1048 | directories by the specified names will be created (including their parents) below the locations |
d491e65e | 1049 | defined in the following table, when the unit is started. Also, the corresponding environment variable |
35f2c0ba | 1050 | is defined with the full path of directories. If multiple directories are set, then in the environment variable |
d491e65e | 1051 | the paths are concatenated with colon (<literal>:</literal>).</para> |
8d00da49 | 1052 | <table> |
d491e65e YW |
1053 | <title>Automatic directory creation and environment variables</title> |
1054 | <tgroup cols='4'> | |
8d00da49 BV |
1055 | <thead> |
1056 | <row> | |
8601482c LP |
1057 | <entry>Directory</entry> |
1058 | <entry>Below path for system units</entry> | |
1059 | <entry>Below path for user units</entry> | |
1060 | <entry>Environment variable set</entry> | |
8d00da49 BV |
1061 | </row> |
1062 | </thead> | |
1063 | <tbody> | |
1064 | <row> | |
1065 | <entry><varname>RuntimeDirectory=</varname></entry> | |
8601482c | 1066 | <entry><filename>/run/</filename></entry> |
8d00da49 | 1067 | <entry><varname>$XDG_RUNTIME_DIR</varname></entry> |
d491e65e | 1068 | <entry><varname>$RUNTIME_DIRECTORY</varname></entry> |
8d00da49 BV |
1069 | </row> |
1070 | <row> | |
1071 | <entry><varname>StateDirectory=</varname></entry> | |
8601482c | 1072 | <entry><filename>/var/lib/</filename></entry> |
8d00da49 | 1073 | <entry><varname>$XDG_CONFIG_HOME</varname></entry> |
d491e65e | 1074 | <entry><varname>$STATE_DIRECTORY</varname></entry> |
8d00da49 BV |
1075 | </row> |
1076 | <row> | |
1077 | <entry><varname>CacheDirectory=</varname></entry> | |
8601482c | 1078 | <entry><filename>/var/cache/</filename></entry> |
8d00da49 | 1079 | <entry><varname>$XDG_CACHE_HOME</varname></entry> |
d491e65e | 1080 | <entry><varname>$CACHE_DIRECTORY</varname></entry> |
8d00da49 BV |
1081 | </row> |
1082 | <row> | |
1083 | <entry><varname>LogsDirectory=</varname></entry> | |
8601482c LP |
1084 | <entry><filename>/var/log/</filename></entry> |
1085 | <entry><varname>$XDG_CONFIG_HOME</varname><filename>/log/</filename></entry> | |
d491e65e | 1086 | <entry><varname>$LOGS_DIRECTORY</varname></entry> |
8d00da49 BV |
1087 | </row> |
1088 | <row> | |
1089 | <entry><varname>ConfigurationDirectory=</varname></entry> | |
8601482c | 1090 | <entry><filename>/etc/</filename></entry> |
8d00da49 | 1091 | <entry><varname>$XDG_CONFIG_HOME</varname></entry> |
d491e65e | 1092 | <entry><varname>$CONFIGURATION_DIRECTORY</varname></entry> |
8d00da49 BV |
1093 | </row> |
1094 | </tbody> | |
1095 | </tgroup> | |
1096 | </table> | |
f86fae61 | 1097 | |
6d463b8a LP |
1098 | <para>In case of <varname>RuntimeDirectory=</varname> the innermost subdirectories are removed when |
1099 | the unit is stopped. It is possible to preserve the specified directories in this case if | |
1100 | <varname>RuntimeDirectoryPreserve=</varname> is configured to <option>restart</option> or | |
1101 | <option>yes</option> (see below). The directories specified with <varname>StateDirectory=</varname>, | |
b8afec21 LP |
1102 | <varname>CacheDirectory=</varname>, <varname>LogsDirectory=</varname>, |
1103 | <varname>ConfigurationDirectory=</varname> are not removed when the unit is stopped.</para> | |
1104 | ||
1105 | <para>Except in case of <varname>ConfigurationDirectory=</varname>, the innermost specified directories will be | |
1106 | owned by the user and group specified in <varname>User=</varname> and <varname>Group=</varname>. If the | |
1107 | specified directories already exist and their owning user or group do not match the configured ones, all files | |
1108 | and directories below the specified directories as well as the directories themselves will have their file | |
1109 | ownership recursively changed to match what is configured. As an optimization, if the specified directories are | |
1110 | already owned by the right user and group, files and directories below of them are left as-is, even if they do | |
1111 | not match what is requested. The innermost specified directories will have their access mode adjusted to the | |
1112 | what is specified in <varname>RuntimeDirectoryMode=</varname>, <varname>StateDirectoryMode=</varname>, | |
1113 | <varname>CacheDirectoryMode=</varname>, <varname>LogsDirectoryMode=</varname> and | |
1114 | <varname>ConfigurationDirectoryMode=</varname>.</para> | |
5aaeeffb | 1115 | |
b8afec21 LP |
1116 | <para>These options imply <varname>BindPaths=</varname> for the specified paths. When combined with |
1117 | <varname>RootDirectory=</varname> or <varname>RootImage=</varname> these paths always reside on the host and | |
1118 | are mounted from there into the unit's file system namespace.</para> | |
798d3a52 | 1119 | |
e9dd6984 ZJS |
1120 | <para>If <varname>DynamicUser=</varname> is used in conjunction with |
1121 | <varname>StateDirectory=</varname>, the logic for <varname>CacheDirectory=</varname> and | |
1122 | <varname>LogsDirectory=</varname> is slightly altered: the directories are created below | |
1123 | <filename>/var/lib/private</filename>, <filename>/var/cache/private</filename> and | |
b8afec21 | 1124 | <filename>/var/log/private</filename>, respectively, which are host directories made inaccessible to |
e9dd6984 ZJS |
1125 | unprivileged users, which ensures that access to these directories cannot be gained through dynamic |
1126 | user ID recycling. Symbolic links are created to hide this difference in behaviour. Both from | |
1127 | perspective of the host and from inside the unit, the relevant directories hence always appear | |
1128 | directly below <filename>/var/lib</filename>, <filename>/var/cache</filename> and | |
1129 | <filename>/var/log</filename>.</para> | |
798d3a52 | 1130 | |
b8afec21 LP |
1131 | <para>Use <varname>RuntimeDirectory=</varname> to manage one or more runtime directories for the unit and bind |
1132 | their lifetime to the daemon runtime. This is particularly useful for unprivileged daemons that cannot create | |
1133 | runtime directories in <filename>/run</filename> due to lack of privileges, and to make sure the runtime | |
1134 | directory is cleaned up automatically after use. For runtime directories that require more complex or different | |
1135 | configuration or lifetime guarantees, please consider using | |
1136 | <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
de7070b4 | 1137 | |
a9a50bd6 PW |
1138 | <para>The directories defined by these options are always created under the standard paths used by systemd |
1139 | (<filename>/var</filename>, <filename>/run</filename>, <filename>/etc</filename>, …). If the service needs | |
1140 | directories in a different location, a different mechanism has to be used to create them.</para> | |
1141 | ||
1142 | <para><citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry> provides | |
1143 | functionality that overlaps with these options. Using these options is recommended, because the lifetime of | |
1144 | the directories is tied directly to the lifetime of the unit, and it is not necessary to ensure that the | |
1145 | <filename>tmpfiles.d</filename> configuration is executed before the unit is started.</para> | |
1146 | ||
8c8208cb LP |
1147 | <para>To remove any of the directories created by these settings, use the <command>systemctl clean |
1148 | …</command> command on the relevant units, see | |
1149 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> for | |
1150 | details.</para> | |
1151 | ||
b8afec21 LP |
1152 | <para>Example: if a system service unit has the following, |
1153 | <programlisting>RuntimeDirectory=foo/bar baz</programlisting> | |
1154 | the service manager creates <filename>/run/foo</filename> (if it does not exist), | |
f8b68539 ZJS |
1155 | |
1156 | <filename index='false'>/run/foo/bar</filename>, and <filename index='false'>/run/baz</filename>. The | |
1157 | directories <filename index='false'>/run/foo/bar</filename> and | |
1158 | <filename index='false'>/run/baz</filename> except <filename index='false'>/run/foo</filename> are | |
b8afec21 | 1159 | owned by the user and group specified in <varname>User=</varname> and <varname>Group=</varname>, and removed |
d491e65e YW |
1160 | when the service is stopped.</para> |
1161 | ||
1162 | <para>Example: if a system service unit has the following, | |
1163 | <programlisting>RuntimeDirectory=foo/bar | |
1164 | StateDirectory=aaa/bbb ccc</programlisting> | |
1165 | then the environment variable <literal>RUNTIME_DIRECTORY</literal> is set with <literal>/run/foo/bar</literal>, and | |
1166 | <literal>STATE_DIRECTORY</literal> is set with <literal>/var/lib/aaa/bbb:/var/lib/ccc</literal>.</para></listitem> | |
798d3a52 ZJS |
1167 | </varlistentry> |
1168 | ||
ece87975 | 1169 | <varlistentry> |
b8afec21 LP |
1170 | <term><varname>RuntimeDirectoryMode=</varname></term> |
1171 | <term><varname>StateDirectoryMode=</varname></term> | |
1172 | <term><varname>CacheDirectoryMode=</varname></term> | |
1173 | <term><varname>LogsDirectoryMode=</varname></term> | |
1174 | <term><varname>ConfigurationDirectoryMode=</varname></term> | |
ece87975 | 1175 | |
b8afec21 LP |
1176 | <listitem><para>Specifies the access mode of the directories specified in <varname>RuntimeDirectory=</varname>, |
1177 | <varname>StateDirectory=</varname>, <varname>CacheDirectory=</varname>, <varname>LogsDirectory=</varname>, or | |
1178 | <varname>ConfigurationDirectory=</varname>, respectively, as an octal number. Defaults to | |
1179 | <constant>0755</constant>. See "Permissions" in <citerefentry | |
1180 | project='man-pages'><refentrytitle>path_resolution</refentrytitle><manvolnum>7</manvolnum></citerefentry> for a | |
1181 | discussion of the meaning of permission bits.</para></listitem> | |
ece87975 IP |
1182 | </varlistentry> |
1183 | ||
798d3a52 | 1184 | <varlistentry> |
b8afec21 LP |
1185 | <term><varname>RuntimeDirectoryPreserve=</varname></term> |
1186 | ||
1187 | <listitem><para>Takes a boolean argument or <option>restart</option>. If set to <option>no</option> (the | |
1188 | default), the directories specified in <varname>RuntimeDirectory=</varname> are always removed when the service | |
1189 | stops. If set to <option>restart</option> the directories are preserved when the service is both automatically | |
1190 | and manually restarted. Here, the automatic restart means the operation specified in | |
1191 | <varname>Restart=</varname>, and manual restart means the one triggered by <command>systemctl restart | |
1192 | foo.service</command>. If set to <option>yes</option>, then the directories are not removed when the service is | |
1193 | stopped. Note that since the runtime directory <filename>/run</filename> is a mount point of | |
1194 | <literal>tmpfs</literal>, then for system services the directories specified in | |
1195 | <varname>RuntimeDirectory=</varname> are removed when the system is rebooted.</para></listitem> | |
798d3a52 ZJS |
1196 | </varlistentry> |
1197 | ||
bd9014c3 YW |
1198 | <varlistentry> |
1199 | <term><varname>TimeoutCleanSec=</varname></term> | |
1200 | <listitem><para>Configures a timeout on the clean-up operation requested through <command>systemctl | |
1201 | clean …</command>, see | |
1202 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> for | |
1203 | details. Takes the usual time values and defaults to <constant>infinity</constant>, i.e. by default | |
201632e3 ZJS |
1204 | no timeout is applied. If a timeout is configured the clean operation will be aborted forcibly when |
1205 | the timeout is reached, potentially leaving resources on disk.</para></listitem> | |
bd9014c3 YW |
1206 | </varlistentry> |
1207 | ||
798d3a52 | 1208 | <varlistentry> |
2a624c36 AP |
1209 | <term><varname>ReadWritePaths=</varname></term> |
1210 | <term><varname>ReadOnlyPaths=</varname></term> | |
1211 | <term><varname>InaccessiblePaths=</varname></term> | |
798d3a52 | 1212 | |
effbd6d2 LP |
1213 | <listitem><para>Sets up a new file system namespace for executed processes. These options may be used to limit |
1214 | access a process might have to the file system hierarchy. Each setting takes a space-separated list of paths | |
1215 | relative to the host's root directory (i.e. the system running the service manager). Note that if paths | |
1216 | contain symlinks, they are resolved relative to the root directory set with | |
915e6d16 | 1217 | <varname>RootDirectory=</varname>/<varname>RootImage=</varname>.</para> |
effbd6d2 | 1218 | |
6b000af4 LP |
1219 | <para>Paths listed in <varname>ReadWritePaths=</varname> are accessible from within the namespace |
1220 | with the same access modes as from outside of it. Paths listed in <varname>ReadOnlyPaths=</varname> | |
1221 | are accessible for reading only, writing will be refused even if the usual file access controls would | |
1222 | permit this. Nest <varname>ReadWritePaths=</varname> inside of <varname>ReadOnlyPaths=</varname> in | |
1223 | order to provide writable subdirectories within read-only directories. Use | |
1224 | <varname>ReadWritePaths=</varname> in order to allow-list specific paths for write access if | |
1225 | <varname>ProtectSystem=strict</varname> is used.</para> | |
e568a92d YW |
1226 | |
1227 | <para>Paths listed in <varname>InaccessiblePaths=</varname> will be made inaccessible for processes inside | |
1228 | the namespace along with everything below them in the file system hierarchy. This may be more restrictive than | |
1229 | desired, because it is not possible to nest <varname>ReadWritePaths=</varname>, <varname>ReadOnlyPaths=</varname>, | |
1230 | <varname>BindPaths=</varname>, or <varname>BindReadOnlyPaths=</varname> inside it. For a more flexible option, | |
1231 | see <varname>TemporaryFileSystem=</varname>.</para> | |
effbd6d2 | 1232 | |
0e18724e | 1233 | <para>Non-directory paths may be specified as well. These options may be specified more than once, |
effbd6d2 LP |
1234 | in which case all paths listed will have limited access from within the namespace. If the empty string is |
1235 | assigned to this option, the specific list is reset, and all prior assignments have no effect.</para> | |
1236 | ||
e778185b | 1237 | <para>Paths in <varname>ReadWritePaths=</varname>, <varname>ReadOnlyPaths=</varname> and |
5327c910 LP |
1238 | <varname>InaccessiblePaths=</varname> may be prefixed with <literal>-</literal>, in which case they will be |
1239 | ignored when they do not exist. If prefixed with <literal>+</literal> the paths are taken relative to the root | |
915e6d16 LP |
1240 | directory of the unit, as configured with <varname>RootDirectory=</varname>/<varname>RootImage=</varname>, |
1241 | instead of relative to the root directory of the host (see above). When combining <literal>-</literal> and | |
1242 | <literal>+</literal> on the same path make sure to specify <literal>-</literal> first, and <literal>+</literal> | |
1243 | second.</para> | |
5327c910 | 1244 | |
0e18724e LP |
1245 | <para>Note that these settings will disconnect propagation of mounts from the unit's processes to the |
1246 | host. This means that this setting may not be used for services which shall be able to install mount points in | |
1247 | the main mount namespace. For <varname>ReadWritePaths=</varname> and <varname>ReadOnlyPaths=</varname> | |
1248 | propagation in the other direction is not affected, i.e. mounts created on the host generally appear in the | |
1249 | unit processes' namespace, and mounts removed on the host also disappear there too. In particular, note that | |
1250 | mount propagation from host to unit will result in unmodified mounts to be created in the unit's namespace, | |
1251 | i.e. writable mounts appearing on the host will be writable in the unit's namespace too, even when propagated | |
1252 | below a path marked with <varname>ReadOnlyPaths=</varname>! Restricting access with these options hence does | |
1253 | not extend to submounts of a directory that are created later on. This means the lock-down offered by that | |
1254 | setting is not complete, and does not offer full protection. </para> | |
1255 | ||
1256 | <para>Note that the effect of these settings may be undone by privileged processes. In order to set up an | |
1257 | effective sandboxed environment for a unit it is thus recommended to combine these settings with either | |
5327c910 | 1258 | <varname>CapabilityBoundingSet=~CAP_SYS_ADMIN</varname> or |
c4d4b5a7 LP |
1259 | <varname>SystemCallFilter=~@mount</varname>.</para> |
1260 | ||
1261 | <xi:include href="system-only.xml" xpointer="plural"/></listitem> | |
798d3a52 ZJS |
1262 | </varlistentry> |
1263 | ||
c10b460b YW |
1264 | <varlistentry> |
1265 | <term><varname>TemporaryFileSystem=</varname></term> | |
1266 | ||
1267 | <listitem><para>Takes a space-separated list of mount points for temporary file systems (tmpfs). If set, a new file | |
1268 | system namespace is set up for executed processes, and a temporary file system is mounted on each mount point. | |
1269 | This option may be specified more than once, in which case temporary file systems are mounted on all listed mount | |
1270 | points. If the empty string is assigned to this option, the list is reset, and all prior assignments have no effect. | |
1271 | Each mount point may optionally be suffixed with a colon (<literal>:</literal>) and mount options such as | |
1272 | <literal>size=10%</literal> or <literal>ro</literal>. By default, each temporary file system is mounted | |
1273 | with <literal>nodev,strictatime,mode=0755</literal>. These can be disabled by explicitly specifying the corresponding | |
1274 | mount options, e.g., <literal>dev</literal> or <literal>nostrictatime</literal>.</para> | |
1275 | ||
1276 | <para>This is useful to hide files or directories not relevant to the processes invoked by the unit, while necessary | |
1277 | files or directories can be still accessed by combining with <varname>BindPaths=</varname> or | |
db8d154d | 1278 | <varname>BindReadOnlyPaths=</varname>:</para> |
c10b460b YW |
1279 | |
1280 | <para>Example: if a unit has the following, | |
1281 | <programlisting>TemporaryFileSystem=/var:ro | |
1282 | BindReadOnlyPaths=/var/lib/systemd</programlisting> | |
1283 | then the invoked processes by the unit cannot see any files or directories under <filename>/var</filename> except for | |
c4d4b5a7 LP |
1284 | <filename>/var/lib/systemd</filename> or its contents.</para> |
1285 | ||
1286 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
c10b460b YW |
1287 | </varlistentry> |
1288 | ||
798d3a52 ZJS |
1289 | <varlistentry> |
1290 | <term><varname>PrivateTmp=</varname></term> | |
1291 | ||
00d9ef85 | 1292 | <listitem><para>Takes a boolean argument. If true, sets up a new file system namespace for the executed |
e9dd6984 ZJS |
1293 | processes and mounts private <filename>/tmp/</filename> and <filename>/var/tmp/</filename> directories inside it |
1294 | that are not shared by processes outside of the namespace. This is useful to secure access to temporary files of | |
00d9ef85 LP |
1295 | the process, but makes sharing between processes via <filename>/tmp</filename> or <filename>/var/tmp</filename> |
1296 | impossible. If this is enabled, all temporary files created by a service in these directories will be removed | |
1297 | after the service is stopped. Defaults to false. It is possible to run two or more units within the same | |
1298 | private <filename>/tmp</filename> and <filename>/var/tmp</filename> namespace by using the | |
798d3a52 | 1299 | <varname>JoinsNamespaceOf=</varname> directive, see |
00d9ef85 | 1300 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for |
effbd6d2 LP |
1301 | details. This setting is implied if <varname>DynamicUser=</varname> is set. For this setting the same |
1302 | restrictions regarding mount propagation and privileges apply as for <varname>ReadOnlyPaths=</varname> and | |
d71f0505 LP |
1303 | related calls, see above. Enabling this setting has the side effect of adding <varname>Requires=</varname> and |
1304 | <varname>After=</varname> dependencies on all mount units necessary to access <filename>/tmp</filename> and | |
1305 | <filename>/var/tmp</filename>. Moreover an implicitly <varname>After=</varname> ordering on | |
1306 | <citerefentry><refentrytitle>systemd-tmpfiles-setup.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
b0238568 ZJS |
1307 | is added.</para> |
1308 | ||
b8afec21 LP |
1309 | <para>Note that the implementation of this setting might be impossible (for example if mount namespaces are not |
1310 | available), and the unit should be written in a way that does not solely rely on this setting for | |
c4d4b5a7 LP |
1311 | security.</para> |
1312 | ||
1313 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
798d3a52 ZJS |
1314 | </varlistentry> |
1315 | ||
1316 | <varlistentry> | |
1317 | <term><varname>PrivateDevices=</varname></term> | |
1318 | ||
b0238568 ZJS |
1319 | <listitem><para>Takes a boolean argument. If true, sets up a new <filename>/dev</filename> mount for the |
1320 | executed processes and only adds API pseudo devices such as <filename>/dev/null</filename>, | |
b8afec21 LP |
1321 | <filename>/dev/zero</filename> or <filename>/dev/random</filename> (as well as the pseudo TTY subsystem) to it, |
1322 | but no physical devices such as <filename>/dev/sda</filename>, system memory <filename>/dev/mem</filename>, | |
1323 | system ports <filename>/dev/port</filename> and others. This is useful to securely turn off physical device | |
1324 | access by the executed process. Defaults to false. Enabling this option will install a system call filter to | |
1325 | block low-level I/O system calls that are grouped in the <varname>@raw-io</varname> set, will also remove | |
1326 | <constant>CAP_MKNOD</constant> and <constant>CAP_SYS_RAWIO</constant> from the capability bounding set for the | |
1327 | unit (see above), and set <varname>DevicePolicy=closed</varname> (see | |
798d3a52 | 1328 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
effbd6d2 LP |
1329 | for details). Note that using this setting will disconnect propagation of mounts from the service to the host |
1330 | (propagation in the opposite direction continues to work). This means that this setting may not be used for | |
b8afec21 LP |
1331 | services which shall be able to install mount points in the main mount namespace. The new |
1332 | <filename>/dev</filename> will be mounted read-only and 'noexec'. The latter may break old programs which try | |
1333 | to set up executable memory by using | |
1334 | <citerefentry><refentrytitle>mmap</refentrytitle><manvolnum>2</manvolnum></citerefentry> of | |
1335 | <filename>/dev/zero</filename> instead of using <constant>MAP_ANON</constant>. For this setting the same | |
1336 | restrictions regarding mount propagation and privileges apply as for <varname>ReadOnlyPaths=</varname> and | |
1337 | related calls, see above. If turned on and if running in user mode, or in system mode, but without the | |
1338 | <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting <varname>User=</varname>), | |
1339 | <varname>NoNewPrivileges=yes</varname> is implied.</para> | |
b0238568 | 1340 | |
b8afec21 LP |
1341 | <para>Note that the implementation of this setting might be impossible (for example if mount namespaces are not |
1342 | available), and the unit should be written in a way that does not solely rely on this setting for | |
c4d4b5a7 LP |
1343 | security.</para> |
1344 | ||
1345 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
798d3a52 ZJS |
1346 | </varlistentry> |
1347 | ||
1348 | <varlistentry> | |
1349 | <term><varname>PrivateNetwork=</varname></term> | |
1350 | ||
b8afec21 LP |
1351 | <listitem><para>Takes a boolean argument. If true, sets up a new network namespace for the executed processes |
1352 | and configures only the loopback network device <literal>lo</literal> inside it. No other network devices will | |
1353 | be available to the executed process. This is useful to turn off network access by the executed process. | |
1354 | Defaults to false. It is possible to run two or more units within the same private network namespace by using | |
1355 | the <varname>JoinsNamespaceOf=</varname> directive, see | |
1356 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for | |
9236cabf LP |
1357 | details. Note that this option will disconnect all socket families from the host, including |
1358 | <constant>AF_NETLINK</constant> and <constant>AF_UNIX</constant>. Effectively, for | |
1359 | <constant>AF_NETLINK</constant> this means that device configuration events received from | |
1360 | <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> are | |
1361 | not delivered to the unit's processes. And for <constant>AF_UNIX</constant> this has the effect that | |
1362 | <constant>AF_UNIX</constant> sockets in the abstract socket namespace of the host will become unavailable to | |
1363 | the unit's processes (however, those located in the file system will continue to be accessible).</para> | |
b8afec21 LP |
1364 | |
1365 | <para>Note that the implementation of this setting might be impossible (for example if network namespaces are | |
1366 | not available), and the unit should be written in a way that does not solely rely on this setting for | |
4107452e LP |
1367 | security.</para> |
1368 | ||
1369 | <para>When this option is used on a socket unit any sockets bound on behalf of this unit will be | |
1370 | bound within a private network namespace. This may be combined with | |
1371 | <varname>JoinsNamespaceOf=</varname> to listen on sockets inside of network namespaces of other | |
c4d4b5a7 LP |
1372 | services.</para> |
1373 | ||
1374 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
4107452e LP |
1375 | </varlistentry> |
1376 | ||
1377 | <varlistentry> | |
1378 | <term><varname>NetworkNamespacePath=</varname></term> | |
1379 | ||
1380 | <listitem><para>Takes an absolute file system path refererring to a Linux network namespace | |
1381 | pseudo-file (i.e. a file like <filename>/proc/$PID/ns/net</filename> or a bind mount or symlink to | |
1382 | one). When set the invoked processes are added to the network namespace referenced by that path. The | |
1383 | path has to point to a valid namespace file at the moment the processes are forked off. If this | |
1384 | option is used <varname>PrivateNetwork=</varname> has no effect. If this option is used together with | |
1385 | <varname>JoinsNamespaceOf=</varname> then it only has an effect if this unit is started before any of | |
1386 | the listed units that have <varname>PrivateNetwork=</varname> or | |
1387 | <varname>NetworkNamespacePath=</varname> configured, as otherwise the network namespace of those | |
1388 | units is reused.</para> | |
1389 | ||
1390 | <para>When this option is used on a socket unit any sockets bound on behalf of this unit will be | |
c4d4b5a7 LP |
1391 | bound within the specified network namespace.</para> |
1392 | ||
1393 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
798d3a52 ZJS |
1394 | </varlistentry> |
1395 | ||
1396 | <varlistentry> | |
d251207d LP |
1397 | <term><varname>PrivateUsers=</varname></term> |
1398 | ||
1399 | <listitem><para>Takes a boolean argument. If true, sets up a new user namespace for the executed processes and | |
1400 | configures a minimal user and group mapping, that maps the <literal>root</literal> user and group as well as | |
1401 | the unit's own user and group to themselves and everything else to the <literal>nobody</literal> user and | |
1402 | group. This is useful to securely detach the user and group databases used by the unit from the rest of the | |
1403 | system, and thus to create an effective sandbox environment. All files, directories, processes, IPC objects and | |
2dd67817 | 1404 | other resources owned by users/groups not equaling <literal>root</literal> or the unit's own will stay visible |
d251207d LP |
1405 | from within the unit but appear owned by the <literal>nobody</literal> user and group. If this mode is enabled, |
1406 | all unit processes are run without privileges in the host user namespace (regardless if the unit's own | |
1407 | user/group is <literal>root</literal> or not). Specifically this means that the process will have zero process | |
1408 | capabilities on the host's user namespace, but full capabilities within the service's user namespace. Settings | |
1409 | such as <varname>CapabilityBoundingSet=</varname> will affect only the latter, and there's no way to acquire | |
1410 | additional capabilities in the host's user namespace. Defaults to off.</para> | |
1411 | ||
5749f855 AZ |
1412 | <para>When this setting is set up by a per-user instance of the service manager, the mapping of the |
1413 | <literal>root</literal> user and group to itself is omitted (unless the user manager is root). | |
1414 | Additionally, in the per-user instance manager case, the | |
1415 | user namespace will be set up before most other namespaces. This means that combining | |
1416 | <varname>PrivateUsers=</varname><option>true</option> with other namespaces will enable use of features not | |
1417 | normally supported by the per-user instances of the service manager.</para> | |
1418 | ||
915e6d16 LP |
1419 | <para>This setting is particularly useful in conjunction with |
1420 | <varname>RootDirectory=</varname>/<varname>RootImage=</varname>, as the need to synchronize the user and group | |
1421 | databases in the root directory and on the host is reduced, as the only users and groups who need to be matched | |
b0238568 ZJS |
1422 | are <literal>root</literal>, <literal>nobody</literal> and the unit's own user and group.</para> |
1423 | ||
b8afec21 LP |
1424 | <para>Note that the implementation of this setting might be impossible (for example if user namespaces are not |
1425 | available), and the unit should be written in a way that does not solely rely on this setting for | |
5749f855 | 1426 | security.</para></listitem> |
d251207d LP |
1427 | </varlistentry> |
1428 | ||
aecd5ac6 TM |
1429 | <varlistentry> |
1430 | <term><varname>ProtectHostname=</varname></term> | |
1431 | ||
1432 | <listitem><para>Takes a boolean argument. When set, sets up a new UTS namespace for the executed | |
1433 | processes. In addition, changing hostname or domainname is prevented. Defaults to off.</para> | |
1434 | ||
8df87b43 LP |
1435 | <para>Note that the implementation of this setting might be impossible (for example if UTS namespaces |
1436 | are not available), and the unit should be written in a way that does not solely rely on this setting | |
1437 | for security.</para> | |
1438 | ||
1439 | <para>Note that when this option is enabled for a service hostname changes no longer propagate from | |
1440 | the system into the service, it is hence not suitable for services that need to take notice of system | |
c4d4b5a7 LP |
1441 | hostname changes dynamically.</para> |
1442 | ||
1443 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
aecd5ac6 TM |
1444 | </varlistentry> |
1445 | ||
022d3345 KK |
1446 | <varlistentry> |
1447 | <term><varname>ProtectClock=</varname></term> | |
1448 | ||
1449 | <listitem><para>Takes a boolean argument. If set, writes to the hardware clock or system clock will be denied. | |
1450 | It is recommended to turn this on for most services that do not need modify the clock. Defaults to off. Enabling | |
1451 | this option removes <constant>CAP_SYS_TIME</constant> and <constant>CAP_WAKE_ALARM</constant> from the | |
1452 | capability bounding set for this unit, installs a system call filter to block calls that can set the | |
1453 | clock, and <varname>DeviceAllow=char-rtc r</varname> is implied. This ensures <filename>/dev/rtc0</filename>, | |
e9dd6984 | 1454 | <filename>/dev/rtc1</filename>, etc. are made read-only to the service. See |
022d3345 KK |
1455 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
1456 | for the details about <varname>DeviceAllow=</varname>.</para> | |
1457 | ||
1458 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
1459 | </varlistentry> | |
1460 | ||
59eeb84b LP |
1461 | <varlistentry> |
1462 | <term><varname>ProtectKernelTunables=</varname></term> | |
1463 | ||
1464 | <listitem><para>Takes a boolean argument. If true, kernel variables accessible through | |
49accde7 DH |
1465 | <filename>/proc/sys</filename>, <filename>/sys</filename>, <filename>/proc/sysrq-trigger</filename>, |
1466 | <filename>/proc/latency_stats</filename>, <filename>/proc/acpi</filename>, | |
1467 | <filename>/proc/timer_stats</filename>, <filename>/proc/fs</filename> and <filename>/proc/irq</filename> will | |
525872bf LP |
1468 | be made read-only to all processes of the unit. Usually, tunable kernel variables should be initialized only at |
1469 | boot-time, for example with the | |
1470 | <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry> mechanism. Few | |
1471 | services need to write to these at runtime; it is hence recommended to turn this on for most services. For this | |
1472 | setting the same restrictions regarding mount propagation and privileges apply as for | |
1473 | <varname>ReadOnlyPaths=</varname> and related calls, see above. Defaults to off. If turned on and if running | |
1474 | in user mode, or in system mode, but without the <constant>CAP_SYS_ADMIN</constant> capability (e.g. services | |
1475 | for which <varname>User=</varname> is set), <varname>NoNewPrivileges=yes</varname> is implied. Note that this | |
1476 | option does not prevent indirect changes to kernel tunables effected by IPC calls to other processes. However, | |
1477 | <varname>InaccessiblePaths=</varname> may be used to make relevant IPC file system objects inaccessible. If | |
1478 | <varname>ProtectKernelTunables=</varname> is set, <varname>MountAPIVFS=yes</varname> is | |
c4d4b5a7 LP |
1479 | implied.</para> |
1480 | ||
1481 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
59eeb84b LP |
1482 | </varlistentry> |
1483 | ||
85265556 DH |
1484 | <varlistentry> |
1485 | <term><varname>ProtectKernelModules=</varname></term> | |
1486 | ||
1b2ad5d9 MB |
1487 | <listitem><para>Takes a boolean argument. If true, explicit module loading will be denied. This allows |
1488 | module load and unload operations to be turned off on modular kernels. It is recommended to turn this on for most services | |
bf2d3d7c | 1489 | that do not need special file systems or extra kernel modules to work. Defaults to off. Enabling this option |
b8afec21 LP |
1490 | removes <constant>CAP_SYS_MODULE</constant> from the capability bounding set for the unit, and installs a |
1491 | system call filter to block module system calls, also <filename>/usr/lib/modules</filename> is made | |
1492 | inaccessible. For this setting the same restrictions regarding mount propagation and privileges apply as for | |
1493 | <varname>ReadOnlyPaths=</varname> and related calls, see above. Note that limited automatic module loading due | |
1494 | to user configuration or kernel mapping tables might still happen as side effect of requested user operations, | |
85265556 DH |
1495 | both privileged and unprivileged. To disable module auto-load feature please see |
1496 | <citerefentry><refentrytitle>sysctl.d</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
1497 | <constant>kernel.modules_disabled</constant> mechanism and | |
b8afec21 LP |
1498 | <filename>/proc/sys/kernel/modules_disabled</filename> documentation. If turned on and if running in user |
1499 | mode, or in system mode, but without the <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting | |
c4d4b5a7 LP |
1500 | <varname>User=</varname>), <varname>NoNewPrivileges=yes</varname> is implied.</para> |
1501 | ||
1502 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
85265556 DH |
1503 | </varlistentry> |
1504 | ||
d916e35b KK |
1505 | <varlistentry> |
1506 | <term><varname>ProtectKernelLogs=</varname></term> | |
1507 | ||
1508 | <listitem><para>Takes a boolean argument. If true, access to the kernel log ring buffer will be denied. It is | |
1509 | recommended to turn this on for most services that do not need to read from or write to the kernel log ring | |
1510 | buffer. Enabling this option removes <constant>CAP_SYSLOG</constant> from the capability bounding set for this | |
1511 | unit, and installs a system call filter to block the | |
1512 | <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
1513 | system call (not to be confused with the libc API | |
1514 | <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
1515 | for userspace logging). The kernel exposes its log buffer to userspace via <filename>/dev/kmsg</filename> and | |
1516 | <filename>/proc/kmsg</filename>. If enabled, these are made inaccessible to all the processes in the unit.</para> | |
1517 | ||
1518 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
1519 | </varlistentry> | |
1520 | ||
59eeb84b LP |
1521 | <varlistentry> |
1522 | <term><varname>ProtectControlGroups=</varname></term> | |
1523 | ||
effbd6d2 LP |
1524 | <listitem><para>Takes a boolean argument. If true, the Linux Control Groups (<citerefentry |
1525 | project='man-pages'><refentrytitle>cgroups</refentrytitle><manvolnum>7</manvolnum></citerefentry>) hierarchies | |
1526 | accessible through <filename>/sys/fs/cgroup</filename> will be made read-only to all processes of the | |
1527 | unit. Except for container managers no services should require write access to the control groups hierarchies; | |
1528 | it is hence recommended to turn this on for most services. For this setting the same restrictions regarding | |
1529 | mount propagation and privileges apply as for <varname>ReadOnlyPaths=</varname> and related calls, see | |
b8afec21 | 1530 | above. Defaults to off. If <varname>ProtectControlGroups=</varname> is set, <varname>MountAPIVFS=yes</varname> |
c4d4b5a7 LP |
1531 | is implied.</para> |
1532 | ||
1533 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
798d3a52 ZJS |
1534 | </varlistentry> |
1535 | ||
1536 | <varlistentry> | |
b8afec21 | 1537 | <term><varname>RestrictAddressFamilies=</varname></term> |
798d3a52 | 1538 | |
6b000af4 LP |
1539 | <listitem><para>Restricts the set of socket address families accessible to the processes of this |
1540 | unit. Takes a space-separated list of address family names to allow-list, such as | |
1541 | <constant>AF_UNIX</constant>, <constant>AF_INET</constant> or <constant>AF_INET6</constant>. When | |
1542 | prefixed with <constant>~</constant> the listed address families will be applied as deny list, | |
1543 | otherwise as allow list. Note that this restricts access to the <citerefentry | |
1544 | project='man-pages'><refentrytitle>socket</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
1545 | system call only. Sockets passed into the process by other means (for example, by using socket | |
1546 | activation with socket units, see | |
1547 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>) | |
1548 | are unaffected. Also, sockets created with <function>socketpair()</function> (which creates connected | |
1549 | AF_UNIX sockets only) are unaffected. Note that this option has no effect on 32-bit x86, s390, s390x, | |
e9dd6984 | 1550 | mips, mips-le, ppc, ppc-le, ppc64, ppc64-le and is ignored (but works correctly on other ABIs, |
6b000af4 LP |
1551 | including x86-64). Note that on systems supporting multiple ABIs (such as x86/x86-64) it is |
1552 | recommended to turn off alternative ABIs for services, so that they cannot be used to circumvent the | |
1553 | restrictions of this option. Specifically, it is recommended to combine this option with | |
1554 | <varname>SystemCallArchitectures=native</varname> or similar. If running in user mode, or in system | |
1555 | mode, but without the <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting | |
1556 | <varname>User=nobody</varname>), <varname>NoNewPrivileges=yes</varname> is implied. By default, no | |
1557 | restrictions apply, all address families are accessible to processes. If assigned the empty string, | |
1558 | any previous address family restriction changes are undone. This setting does not affect commands | |
1559 | prefixed with <literal>+</literal>.</para> | |
b8afec21 LP |
1560 | |
1561 | <para>Use this option to limit exposure of processes to remote access, in particular via exotic and sensitive | |
1562 | network protocols, such as <constant>AF_PACKET</constant>. Note that in most cases, the local | |
6b000af4 | 1563 | <constant>AF_UNIX</constant> address family should be included in the configured allow list as it is frequently |
b8afec21 LP |
1564 | used for local communication, including for |
1565 | <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
1566 | logging.</para></listitem> | |
798d3a52 ZJS |
1567 | </varlistentry> |
1568 | ||
1569 | <varlistentry> | |
b8afec21 | 1570 | <term><varname>RestrictNamespaces=</varname></term> |
798d3a52 | 1571 | |
b8afec21 LP |
1572 | <listitem><para>Restricts access to Linux namespace functionality for the processes of this unit. For details |
1573 | about Linux namespaces, see <citerefentry | |
1574 | project='man-pages'><refentrytitle>namespaces</refentrytitle><manvolnum>7</manvolnum></citerefentry>. Either | |
1575 | takes a boolean argument, or a space-separated list of namespace type identifiers. If false (the default), no | |
1576 | restrictions on namespace creation and switching are made. If true, access to any kind of namespacing is | |
1577 | prohibited. Otherwise, a space-separated list of namespace type identifiers must be specified, consisting of | |
1578 | any combination of: <constant>cgroup</constant>, <constant>ipc</constant>, <constant>net</constant>, | |
1579 | <constant>mnt</constant>, <constant>pid</constant>, <constant>user</constant> and <constant>uts</constant>. Any | |
1580 | namespace type listed is made accessible to the unit's processes, access to namespace types not listed is | |
6b000af4 | 1581 | prohibited (allow-listing). By prepending the list with a single tilde character (<literal>~</literal>) the |
b8afec21 | 1582 | effect may be inverted: only the listed namespace types will be made inaccessible, all unlisted ones are |
6b000af4 | 1583 | permitted (deny-listing). If the empty string is assigned, the default namespace restrictions are applied, |
53255e53 YW |
1584 | which is equivalent to false. This option may appear more than once, in which case the namespace types are |
1585 | merged by <constant>OR</constant>, or by <constant>AND</constant> if the lines are prefixed with | |
1586 | <literal>~</literal> (see examples below). Internally, this setting limits access to the | |
b8afec21 LP |
1587 | <citerefentry><refentrytitle>unshare</refentrytitle><manvolnum>2</manvolnum></citerefentry>, |
1588 | <citerefentry><refentrytitle>clone</refentrytitle><manvolnum>2</manvolnum></citerefentry> and | |
1589 | <citerefentry><refentrytitle>setns</refentrytitle><manvolnum>2</manvolnum></citerefentry> system calls, taking | |
1590 | the specified flags parameters into account. Note that — if this option is used — in addition to restricting | |
1591 | creation and switching of the specified types of namespaces (or all of them, if true) access to the | |
1592 | <function>setns()</function> system call with a zero flags parameter is prohibited. This setting is only | |
1593 | supported on x86, x86-64, mips, mips-le, mips64, mips64-le, mips64-n32, mips64-le-n32, ppc64, ppc64-le, s390 | |
1594 | and s390x, and enforces no restrictions on other architectures. If running in user mode, or in system mode, but | |
1595 | without the <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting <varname>User=</varname>), | |
53255e53 YW |
1596 | <varname>NoNewPrivileges=yes</varname> is implied.</para> |
1597 | ||
1598 | <para>Example: if a unit has the following, | |
1599 | <programlisting>RestrictNamespaces=cgroup ipc | |
1600 | RestrictNamespaces=cgroup net</programlisting> | |
1601 | then <constant>cgroup</constant>, <constant>ipc</constant>, and <constant>net</constant> are set. | |
1602 | If the second line is prefixed with <literal>~</literal>, e.g., | |
1603 | <programlisting>RestrictNamespaces=cgroup ipc | |
1604 | RestrictNamespaces=~cgroup net</programlisting> | |
1605 | then, only <constant>ipc</constant> is set.</para></listitem> | |
798d3a52 ZJS |
1606 | </varlistentry> |
1607 | ||
023a4f67 | 1608 | <varlistentry> |
b8afec21 | 1609 | <term><varname>LockPersonality=</varname></term> |
023a4f67 | 1610 | |
b8afec21 LP |
1611 | <listitem><para>Takes a boolean argument. If set, locks down the <citerefentry |
1612 | project='man-pages'><refentrytitle>personality</refentrytitle><manvolnum>2</manvolnum></citerefentry> system | |
1613 | call so that the kernel execution domain may not be changed from the default or the personality selected with | |
1614 | <varname>Personality=</varname> directive. This may be useful to improve security, because odd personality | |
1615 | emulations may be poorly tested and source of vulnerabilities. If running in user mode, or in system mode, but | |
1616 | without the <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting <varname>User=</varname>), | |
1617 | <varname>NoNewPrivileges=yes</varname> is implied.</para></listitem> | |
023a4f67 LP |
1618 | </varlistentry> |
1619 | ||
798d3a52 | 1620 | <varlistentry> |
b8afec21 | 1621 | <term><varname>MemoryDenyWriteExecute=</varname></term> |
798d3a52 | 1622 | |
b8afec21 LP |
1623 | <listitem><para>Takes a boolean argument. If set, attempts to create memory mappings that are writable and |
1624 | executable at the same time, or to change existing memory mappings to become executable, or mapping shared | |
1625 | memory segments as executable are prohibited. Specifically, a system call filter is added that rejects | |
1626 | <citerefentry><refentrytitle>mmap</refentrytitle><manvolnum>2</manvolnum></citerefentry> system calls with both | |
1627 | <constant>PROT_EXEC</constant> and <constant>PROT_WRITE</constant> set, | |
1628 | <citerefentry><refentrytitle>mprotect</refentrytitle><manvolnum>2</manvolnum></citerefentry> or | |
1629 | <citerefentry><refentrytitle>pkey_mprotect</refentrytitle><manvolnum>2</manvolnum></citerefentry> system calls | |
1630 | with <constant>PROT_EXEC</constant> set and | |
1631 | <citerefentry><refentrytitle>shmat</refentrytitle><manvolnum>2</manvolnum></citerefentry> system calls with | |
1632 | <constant>SHM_EXEC</constant> set. Note that this option is incompatible with programs and libraries that | |
1633 | generate program code dynamically at runtime, including JIT execution engines, executable stacks, and code | |
1634 | "trampoline" feature of various C compilers. This option improves service security, as it makes harder for | |
10d44e72 TM |
1635 | software exploits to change running code dynamically. However, the protection can be circumvented, if |
1636 | the service can write to a filesystem, which is not mounted with <constant>noexec</constant> (such as | |
1637 | <filename>/dev/shm</filename>), or it can use <function>memfd_create()</function>. This can be | |
1638 | prevented by making such file systems inaccessible to the service | |
1639 | (e.g. <varname>InaccessiblePaths=/dev/shm</varname>) and installing further system call filters | |
1640 | (<varname>SystemCallFilter=~memfd_create</varname>). Note that this feature is fully available on | |
1641 | x86-64, and partially on x86. Specifically, the <function>shmat()</function> protection is not | |
1642 | available on x86. Note that on systems supporting multiple ABIs (such as x86/x86-64) it is | |
1643 | recommended to turn off alternative ABIs for services, so that they cannot be used to circumvent the | |
1644 | restrictions of this option. Specifically, it is recommended to combine this option with | |
1645 | <varname>SystemCallArchitectures=native</varname> or similar. If running in user mode, or in system | |
1646 | mode, but without the <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting | |
1647 | <varname>User=</varname>), <varname>NoNewPrivileges=yes</varname> is implied.</para></listitem> | |
798d3a52 ZJS |
1648 | </varlistentry> |
1649 | ||
1650 | <varlistentry> | |
b8afec21 | 1651 | <term><varname>RestrictRealtime=</varname></term> |
798d3a52 | 1652 | |
b8afec21 LP |
1653 | <listitem><para>Takes a boolean argument. If set, any attempts to enable realtime scheduling in a process of |
1654 | the unit are refused. This restricts access to realtime task scheduling policies such as | |
1655 | <constant>SCHED_FIFO</constant>, <constant>SCHED_RR</constant> or <constant>SCHED_DEADLINE</constant>. See | |
1656 | <citerefentry project='man-pages'><refentrytitle>sched</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
1657 | for details about these scheduling policies. If running in user mode, or in system mode, but without the | |
1658 | <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting <varname>User=</varname>), | |
1659 | <varname>NoNewPrivileges=yes</varname> is implied. Realtime scheduling policies may be used to monopolize CPU | |
1660 | time for longer periods of time, and may hence be used to lock up or otherwise trigger Denial-of-Service | |
1661 | situations on the system. It is hence recommended to restrict access to realtime scheduling to the few programs | |
1662 | that actually require them. Defaults to off.</para></listitem> | |
798d3a52 ZJS |
1663 | </varlistentry> |
1664 | ||
7445db6e LP |
1665 | <varlistentry> |
1666 | <term><varname>RestrictSUIDSGID=</varname></term> | |
1667 | ||
1668 | <listitem><para>Takes a boolean argument. If set, any attempts to set the set-user-ID (SUID) or | |
1669 | set-group-ID (SGID) bits on files or directories will be denied (for details on these bits see | |
1670 | <citerefentry | |
1671 | project='man-pages'><refentrytitle>inode</refentrytitle><manvolnum>7</manvolnum></citerefentry>). If | |
1672 | running in user mode, or in system mode, but without the <constant>CAP_SYS_ADMIN</constant> | |
1673 | capability (e.g. setting <varname>User=</varname>), <varname>NoNewPrivileges=yes</varname> is | |
1674 | implied. As the SUID/SGID bits are mechanisms to elevate privileges, and allows users to acquire the | |
1675 | identity of other users, it is recommended to restrict creation of SUID/SGID files to the few | |
1676 | programs that actually require them. Note that this restricts marking of any type of file system | |
1677 | object with these bits, including both regular files and directories (where the SGID is a different | |
bf65b7e0 LP |
1678 | meaning than for files, see documentation). This option is implied if <varname>DynamicUser=</varname> |
1679 | is enabled. Defaults to off.</para></listitem> | |
7445db6e LP |
1680 | </varlistentry> |
1681 | ||
798d3a52 | 1682 | <varlistentry> |
b8afec21 | 1683 | <term><varname>RemoveIPC=</varname></term> |
798d3a52 | 1684 | |
b8afec21 LP |
1685 | <listitem><para>Takes a boolean parameter. If set, all System V and POSIX IPC objects owned by the user and |
1686 | group the processes of this unit are run as are removed when the unit is stopped. This setting only has an | |
1687 | effect if at least one of <varname>User=</varname>, <varname>Group=</varname> and | |
1688 | <varname>DynamicUser=</varname> are used. It has no effect on IPC objects owned by the root user. Specifically, | |
1689 | this removes System V semaphores, as well as System V and POSIX shared memory segments and message queues. If | |
1690 | multiple units use the same user or group the IPC objects are removed when the last of these units is | |
c4d4b5a7 LP |
1691 | stopped. This setting is implied if <varname>DynamicUser=</varname> is set.</para> |
1692 | ||
1693 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
798d3a52 ZJS |
1694 | </varlistentry> |
1695 | ||
2f2e14b2 LP |
1696 | <varlistentry> |
1697 | <term><varname>PrivateMounts=</varname></term> | |
1698 | ||
1699 | <listitem><para>Takes a boolean parameter. If set, the processes of this unit will be run in their own private | |
1700 | file system (mount) namespace with all mount propagation from the processes towards the host's main file system | |
1701 | namespace turned off. This means any file system mount points established or removed by the unit's processes | |
1702 | will be private to them and not be visible to the host. However, file system mount points established or | |
1703 | removed on the host will be propagated to the unit's processes. See <citerefentry | |
1704 | project='man-pages'><refentrytitle>mount_namespaces</refentrytitle><manvolnum>7</manvolnum></citerefentry> for | |
1705 | details on file system namespaces. Defaults to off.</para> | |
1706 | ||
1707 | <para>When turned on, this executes three operations for each invoked process: a new | |
1708 | <constant>CLONE_NEWNS</constant> namespace is created, after which all existing mounts are remounted to | |
1709 | <constant>MS_SLAVE</constant> to disable propagation from the unit's processes to the host (but leaving | |
1710 | propagation in the opposite direction in effect). Finally, the mounts are remounted again to the propagation | |
1711 | mode configured with <varname>MountFlags=</varname>, see below.</para> | |
1712 | ||
1713 | <para>File system namespaces are set up individually for each process forked off by the service manager. Mounts | |
1714 | established in the namespace of the process created by <varname>ExecStartPre=</varname> will hence be cleaned | |
1715 | up automatically as soon as that process exits and will not be available to subsequent processes forked off for | |
1716 | <varname>ExecStart=</varname> (and similar applies to the various other commands configured for | |
1717 | units). Similarly, <varname>JoinsNamespaceOf=</varname> does not permit sharing kernel mount namespaces between | |
1718 | units, it only enables sharing of the <filename>/tmp/</filename> and <filename>/var/tmp/</filename> | |
1719 | directories.</para> | |
1720 | ||
1721 | <para>Other file system namespace unit settings — <varname>PrivateMounts=</varname>, | |
1722 | <varname>PrivateTmp=</varname>, <varname>PrivateDevices=</varname>, <varname>ProtectSystem=</varname>, | |
1723 | <varname>ProtectHome=</varname>, <varname>ReadOnlyPaths=</varname>, <varname>InaccessiblePaths=</varname>, | |
1724 | <varname>ReadWritePaths=</varname>, … — also enable file system namespacing in a fashion equivalent to this | |
1725 | option. Hence it is primarily useful to explicitly request this behaviour if none of the other settings are | |
c4d4b5a7 LP |
1726 | used.</para> |
1727 | ||
1728 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
2f2e14b2 LP |
1729 | </varlistentry> |
1730 | ||
798d3a52 | 1731 | <varlistentry> |
b8afec21 | 1732 | <term><varname>MountFlags=</varname></term> |
798d3a52 | 1733 | |
2f2e14b2 LP |
1734 | <listitem><para>Takes a mount propagation setting: <option>shared</option>, <option>slave</option> or |
1735 | <option>private</option>, which controls whether file system mount points in the file system namespaces set up | |
1736 | for this unit's processes will receive or propagate mounts and unmounts from other file system namespaces. See | |
1737 | <citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
1738 | for details on mount propagation, and the three propagation flags in particular.</para> | |
1739 | ||
1740 | <para>This setting only controls the <emphasis>final</emphasis> propagation setting in effect on all mount | |
1741 | points of the file system namespace created for each process of this unit. Other file system namespacing unit | |
1742 | settings (see the discussion in <varname>PrivateMounts=</varname> above) will implicitly disable mount and | |
1743 | unmount propagation from the unit's processes towards the host by changing the propagation setting of all mount | |
86b52a39 | 1744 | points in the unit's file system namespace to <option>slave</option> first. Setting this option to |
923f9101 | 1745 | <option>shared</option> does not reestablish propagation in that case.</para> |
2f2e14b2 LP |
1746 | |
1747 | <para>If not set – but file system namespaces are enabled through another file system namespace unit setting – | |
1748 | <option>shared</option> mount propagation is used, but — as mentioned — as <option>slave</option> is applied | |
1749 | first, propagation from the unit's processes to the host is still turned off.</para> | |
1750 | ||
cd990847 | 1751 | <para>It is not recommended to use <option>private</option> mount propagation for units, as this means |
2f2e14b2 LP |
1752 | temporary mounts (such as removable media) of the host will stay mounted and thus indefinitely busy in forked |
1753 | off processes, as unmount propagation events won't be received by the file system namespace of the unit.</para> | |
1754 | ||
1755 | <para>Usually, it is best to leave this setting unmodified, and use higher level file system namespacing | |
1756 | options instead, in particular <varname>PrivateMounts=</varname>, see above.</para> | |
c4d4b5a7 LP |
1757 | |
1758 | <xi:include href="system-only.xml" xpointer="singular"/></listitem> | |
798d3a52 ZJS |
1759 | </varlistentry> |
1760 | ||
b8afec21 LP |
1761 | </variablelist> |
1762 | </refsect1> | |
a6fabe38 | 1763 | |
b8afec21 LP |
1764 | <refsect1> |
1765 | <title>System Call Filtering</title> | |
e0e2ecd5 | 1766 | <variablelist class='unit-directives'> |
798d3a52 ZJS |
1767 | |
1768 | <varlistentry> | |
1769 | <term><varname>SystemCallFilter=</varname></term> | |
1770 | ||
330703fb LP |
1771 | <listitem><para>Takes a space-separated list of system call names. If this setting is used, all |
1772 | system calls executed by the unit processes except for the listed ones will result in immediate | |
6b000af4 | 1773 | process termination with the <constant>SIGSYS</constant> signal (allow-listing). (See |
330703fb LP |
1774 | <varname>SystemCallErrorNumber=</varname> below for changing the default action). If the first |
1775 | character of the list is <literal>~</literal>, the effect is inverted: only the listed system calls | |
6b000af4 | 1776 | will result in immediate process termination (deny-listing). Deny-listed system calls and system call |
330703fb LP |
1777 | groups may optionally be suffixed with a colon (<literal>:</literal>) and <literal>errno</literal> |
1778 | error number (between 0 and 4095) or errno name such as <constant>EPERM</constant>, | |
1779 | <constant>EACCES</constant> or <constant>EUCLEAN</constant> (see <citerefentry | |
1780 | project='man-pages'><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry> for a | |
6b000af4 | 1781 | full list). This value will be returned when a deny-listed system call is triggered, instead of |
330703fb LP |
1782 | terminating the processes immediately. This value takes precedence over the one given in |
1783 | <varname>SystemCallErrorNumber=</varname>, see below. If running in user mode, or in system mode, | |
1784 | but without the <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting | |
1785 | <varname>User=nobody</varname>), <varname>NoNewPrivileges=yes</varname> is implied. This feature | |
1786 | makes use of the Secure Computing Mode 2 interfaces of the kernel ('seccomp filtering') and is useful | |
1787 | for enforcing a minimal sandboxing environment. Note that the <function>execve</function>, | |
1788 | <function>exit</function>, <function>exit_group</function>, <function>getrlimit</function>, | |
1789 | <function>rt_sigreturn</function>, <function>sigreturn</function> system calls and the system calls | |
6b000af4 | 1790 | for querying time and sleeping are implicitly allow-listed and do not need to be listed |
330703fb LP |
1791 | explicitly. This option may be specified more than once, in which case the filter masks are |
1792 | merged. If the empty string is assigned, the filter is reset, all prior assignments will have no | |
1793 | effect. This does not affect commands prefixed with <literal>+</literal>.</para> | |
798d3a52 | 1794 | |
0b8fab97 LP |
1795 | <para>Note that on systems supporting multiple ABIs (such as x86/x86-64) it is recommended to turn off |
1796 | alternative ABIs for services, so that they cannot be used to circumvent the restrictions of this | |
1797 | option. Specifically, it is recommended to combine this option with | |
1798 | <varname>SystemCallArchitectures=native</varname> or similar.</para> | |
1799 | ||
2ca8dc15 LP |
1800 | <para>Note that strict system call filters may impact execution and error handling code paths of the service |
1801 | invocation. Specifically, access to the <function>execve</function> system call is required for the execution | |
1802 | of the service binary — if it is blocked service invocation will necessarily fail. Also, if execution of the | |
1803 | service binary fails for some reason (for example: missing service executable), the error handling logic might | |
1804 | require access to an additional set of system calls in order to process and log this failure correctly. It | |
1805 | might be necessary to temporarily disable system call filters in order to simplify debugging of such | |
1806 | failures.</para> | |
1807 | ||
6b000af4 LP |
1808 | <para>If you specify both types of this option (i.e. allow-listing and deny-listing), the first |
1809 | encountered will take precedence and will dictate the default action (termination or approval of a | |
1810 | system call). Then the next occurrences of this option will add or delete the listed system calls | |
1811 | from the set of the filtered system calls, depending of its type and the default action. (For | |
1812 | example, if you have started with an allow list rule for <function>read</function> and | |
1813 | <function>write</function>, and right after it add a deny list rule for <function>write</function>, | |
1814 | then <function>write</function> will be removed from the set.)</para> | |
b8afec21 LP |
1815 | |
1816 | <para>As the number of possible system calls is large, predefined sets of system calls are provided. A set | |
1817 | starts with <literal>@</literal> character, followed by name of the set. | |
201c1cc2 TM |
1818 | |
1819 | <table> | |
1820 | <title>Currently predefined system call sets</title> | |
1821 | ||
1822 | <tgroup cols='2'> | |
1823 | <colspec colname='set' /> | |
1824 | <colspec colname='description' /> | |
1825 | <thead> | |
1826 | <row> | |
1827 | <entry>Set</entry> | |
1828 | <entry>Description</entry> | |
1829 | </row> | |
1830 | </thead> | |
1831 | <tbody> | |
44898c53 LP |
1832 | <row> |
1833 | <entry>@aio</entry> | |
1834 | <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> | |
1835 | </row> | |
133ddbbe LP |
1836 | <row> |
1837 | <entry>@basic-io</entry> | |
1838 | <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> | |
1839 | </row> | |
44898c53 LP |
1840 | <row> |
1841 | <entry>@chown</entry> | |
1842 | <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> | |
1843 | </row> | |
201c1cc2 TM |
1844 | <row> |
1845 | <entry>@clock</entry> | |
1f9ac68b LP |
1846 | <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> |
1847 | </row> | |
1848 | <row> | |
1849 | <entry>@cpu-emulation</entry> | |
1850 | <entry>System calls for CPU emulation functionality (<citerefentry project='man-pages'><refentrytitle>vm86</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry> | |
1851 | </row> | |
1852 | <row> | |
1853 | <entry>@debug</entry> | |
1854 | <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 | 1855 | </row> |
1a1b13c9 LP |
1856 | <row> |
1857 | <entry>@file-system</entry> | |
e9dd6984 | 1858 | <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> |
1a1b13c9 | 1859 | </row> |
201c1cc2 TM |
1860 | <row> |
1861 | <entry>@io-event</entry> | |
1f9ac68b | 1862 | <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 |
1863 | </row> |
1864 | <row> | |
1865 | <entry>@ipc</entry> | |
cd5bfd7e | 1866 | <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 |
1867 | </row> |
1868 | <row> | |
1869 | <entry>@keyring</entry> | |
1870 | <entry>Kernel keyring access (<citerefentry project='man-pages'><refentrytitle>keyctl</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry> | |
201c1cc2 | 1871 | </row> |
cd0ddf6f LP |
1872 | <row> |
1873 | <entry>@memlock</entry> | |
e9dd6984 | 1874 | <entry>Locking of memory in 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> |
cd0ddf6f | 1875 | </row> |
201c1cc2 TM |
1876 | <row> |
1877 | <entry>@module</entry> | |
d5efc18b | 1878 | <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 |
1879 | </row> |
1880 | <row> | |
1881 | <entry>@mount</entry> | |
d5efc18b | 1882 | <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 |
1883 | </row> |
1884 | <row> | |
1885 | <entry>@network-io</entry> | |
1f9ac68b | 1886 | <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 |
1887 | </row> |
1888 | <row> | |
1889 | <entry>@obsolete</entry> | |
1f9ac68b | 1890 | <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 |
1891 | </row> |
1892 | <row> | |
1893 | <entry>@privileged</entry> | |
1f9ac68b | 1894 | <entry>All system calls which need super-user capabilities (<citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>)</entry> |
201c1cc2 TM |
1895 | </row> |
1896 | <row> | |
1897 | <entry>@process</entry> | |
e9dd6984 | 1898 | <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 |
1899 | </row> |
1900 | <row> | |
1901 | <entry>@raw-io</entry> | |
aa6b9cec | 1902 | <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 | 1903 | </row> |
bd2ab3f4 LP |
1904 | <row> |
1905 | <entry>@reboot</entry> | |
1906 | <entry>System calls for rebooting and reboot preparation (<citerefentry project='man-pages'><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <function>kexec()</function>, …)</entry> | |
1907 | </row> | |
133ddbbe LP |
1908 | <row> |
1909 | <entry>@resources</entry> | |
1910 | <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> | |
1911 | </row> | |
6eaaeee9 LP |
1912 | <row> |
1913 | <entry>@setuid</entry> | |
1914 | <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> | |
1915 | </row> | |
cd0ddf6f LP |
1916 | <row> |
1917 | <entry>@signal</entry> | |
1918 | <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> | |
1919 | </row> | |
bd2ab3f4 LP |
1920 | <row> |
1921 | <entry>@swap</entry> | |
1922 | <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> | |
1923 | </row> | |
44898c53 LP |
1924 | <row> |
1925 | <entry>@sync</entry> | |
e9dd6984 | 1926 | <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> |
44898c53 | 1927 | </row> |
70526841 LP |
1928 | <row> |
1929 | <entry>@system-service</entry> | |
6b000af4 | 1930 | <entry>A reasonable set of system calls used by common system services, excluding any special purpose calls. This is the recommended starting point for allow-listing system calls for system services, as it contains what is typically needed by system services, but excludes overly specific interfaces. For example, the following APIs are excluded: <literal>@clock</literal>, <literal>@mount</literal>, <literal>@swap</literal>, <literal>@reboot</literal>.</entry> |
70526841 | 1931 | </row> |
cd0ddf6f LP |
1932 | <row> |
1933 | <entry>@timer</entry> | |
1934 | <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> | |
1935 | </row> | |
201c1cc2 TM |
1936 | </tbody> |
1937 | </tgroup> | |
1938 | </table> | |
1939 | ||
b8afec21 LP |
1940 | Note, that as new system calls are added to the kernel, additional system calls might be added to the groups |
1941 | above. Contents of the sets may also change between systemd versions. In addition, the list of system calls | |
1942 | depends on the kernel version and architecture for which systemd was compiled. Use | |
1943 | <command>systemd-analyze syscall-filter</command> to list the actual list of system calls in each | |
1944 | filter.</para> | |
effbd6d2 | 1945 | |
6b000af4 LP |
1946 | <para>Generally, allow-listing system calls (rather than deny-listing) is the safer mode of |
1947 | operation. It is recommended to enforce system call allow lists for all long-running system | |
1948 | services. Specifically, the following lines are a relatively safe basic choice for the majority of | |
1949 | system services:</para> | |
70526841 LP |
1950 | |
1951 | <programlisting>[Service] | |
1952 | SystemCallFilter=@system-service | |
1953 | SystemCallErrorNumber=EPERM</programlisting> | |
1954 | ||
330703fb LP |
1955 | <para>Note that various kernel system calls are defined redundantly: there are multiple system calls |
1956 | for executing the same operation. For example, the <function>pidfd_send_signal()</function> system | |
1957 | call may be used to execute operations similar to what can be done with the older | |
1958 | <function>kill()</function> system call, hence blocking the latter without the former only provides | |
1959 | weak protection. Since new system calls are added regularly to the kernel as development progresses, | |
6b000af4 LP |
1960 | keeping system call deny lists comprehensive requires constant work. It is thus recommended to use |
1961 | allow-listing instead, which offers the benefit that new system calls are by default implicitly | |
1962 | blocked until the allow list is updated.</para> | |
330703fb LP |
1963 | |
1964 | <para>Also note that a number of system calls are required to be accessible for the dynamic linker to | |
1965 | work. The dynamic linker is required for running most regular programs (specifically: all dynamic ELF | |
1966 | binaries, which is how most distributions build packaged programs). This means that blocking these | |
1967 | system calls (which include <function>open()</function>, <function>openat()</function> or | |
1968 | <function>mmap()</function>) will make most programs typically shipped with generic distributions | |
1969 | unusable.</para> | |
1970 | ||
effbd6d2 LP |
1971 | <para>It is recommended to combine the file system namespacing related options with |
1972 | <varname>SystemCallFilter=~@mount</varname>, in order to prohibit the unit's processes to undo the | |
1973 | mappings. Specifically these are the options <varname>PrivateTmp=</varname>, | |
1974 | <varname>PrivateDevices=</varname>, <varname>ProtectSystem=</varname>, <varname>ProtectHome=</varname>, | |
1975 | <varname>ProtectKernelTunables=</varname>, <varname>ProtectControlGroups=</varname>, | |
022d3345 | 1976 | <varname>ProtectKernelLogs=</varname>, <varname>ProtectClock=</varname>, <varname>ReadOnlyPaths=</varname>, |
d916e35b | 1977 | <varname>InaccessiblePaths=</varname> and <varname>ReadWritePaths=</varname>.</para></listitem> |
798d3a52 ZJS |
1978 | </varlistentry> |
1979 | ||
1980 | <varlistentry> | |
1981 | <term><varname>SystemCallErrorNumber=</varname></term> | |
1982 | ||
330703fb LP |
1983 | <listitem><para>Takes an <literal>errno</literal> error number (between 1 and 4095) or errno name |
1984 | such as <constant>EPERM</constant>, <constant>EACCES</constant> or <constant>EUCLEAN</constant>, to | |
1985 | return when the system call filter configured with <varname>SystemCallFilter=</varname> is triggered, | |
1986 | instead of terminating the process immediately. See <citerefentry | |
1987 | project='man-pages'><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry> for a | |
1988 | full list of error codes. When this setting is not used, or when the empty string is assigned, the | |
1989 | process will be terminated immediately when the filter is triggered.</para></listitem> | |
798d3a52 ZJS |
1990 | </varlistentry> |
1991 | ||
1992 | <varlistentry> | |
1993 | <term><varname>SystemCallArchitectures=</varname></term> | |
1994 | ||
0b8fab97 LP |
1995 | <listitem><para>Takes a space-separated list of architecture identifiers to include in the system call |
1996 | filter. The known architecture identifiers are the same as for <varname>ConditionArchitecture=</varname> | |
1997 | described in <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
1998 | as well as <constant>x32</constant>, <constant>mips64-n32</constant>, <constant>mips64-le-n32</constant>, and | |
2428aaf8 | 1999 | the special identifier <constant>native</constant>. The special identifier <constant>native</constant> |
62a0680b AJ |
2000 | implicitly maps to the native architecture of the system (or more precisely: to the architecture the system |
2001 | manager is compiled for). If running in user mode, or in system mode, but without the | |
2002 | <constant>CAP_SYS_ADMIN</constant> capability (e.g. setting <varname>User=nobody</varname>), | |
2003 | <varname>NoNewPrivileges=yes</varname> is implied. By default, this option is set to the empty list, i.e. no | |
e9dd6984 | 2004 | filtering is applied.</para> |
0b8fab97 | 2005 | |
2428aaf8 AJ |
2006 | <para>If this setting is used, processes of this unit will only be permitted to call native system calls, and |
2007 | system calls of the specified architectures. For the purposes of this option, the x32 architecture is treated | |
2008 | as including x86-64 system calls. However, this setting still fulfills its purpose, as explained below, on | |
2009 | x32.</para> | |
2010 | ||
2011 | <para>System call filtering is not equally effective on all architectures. For example, on x86 | |
0b8fab97 LP |
2012 | filtering of network socket-related calls is not possible, due to ABI limitations — a limitation that x86-64 |
2013 | does not have, however. On systems supporting multiple ABIs at the same time — such as x86/x86-64 — it is hence | |
2014 | recommended to limit the set of permitted system call architectures so that secondary ABIs may not be used to | |
2015 | circumvent the restrictions applied to the native ABI of the system. In particular, setting | |
c29ebc1a | 2016 | <varname>SystemCallArchitectures=native</varname> is a good choice for disabling non-native ABIs.</para> |
0b8fab97 | 2017 | |
b8afec21 LP |
2018 | <para>System call architectures may also be restricted system-wide via the |
2019 | <varname>SystemCallArchitectures=</varname> option in the global configuration. See | |
2020 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> for | |
2021 | details.</para></listitem> | |
2022 | </varlistentry> | |
2023 | ||
2024 | </variablelist> | |
2025 | </refsect1> | |
2026 | ||
2027 | <refsect1> | |
2028 | <title>Environment</title> | |
2029 | ||
e0e2ecd5 | 2030 | <variablelist class='unit-directives'> |
b8afec21 LP |
2031 | |
2032 | <varlistentry> | |
2033 | <term><varname>Environment=</varname></term> | |
2034 | ||
2035 | <listitem><para>Sets environment variables for executed processes. Takes a space-separated list of variable | |
2036 | assignments. This option may be specified more than once, in which case all listed variables will be set. If | |
2037 | the same variable is set twice, the later setting will override the earlier setting. If the empty string is | |
2038 | assigned to this option, the list of environment variables is reset, all prior assignments have no | |
2039 | effect. Variable expansion is not performed inside the strings, however, specifier expansion is possible. The $ | |
2040 | character has no special meaning. If you need to assign a value containing spaces or the equals sign to a | |
2041 | variable, use double quotes (") for the assignment.</para> | |
2042 | ||
2043 | <para>Example: | |
2044 | <programlisting>Environment="VAR1=word1 word2" VAR2=word3 "VAR3=$word 5 6"</programlisting> | |
2045 | gives three variables <literal>VAR1</literal>, | |
2046 | <literal>VAR2</literal>, <literal>VAR3</literal> | |
2047 | with the values <literal>word1 word2</literal>, | |
2048 | <literal>word3</literal>, <literal>$word 5 6</literal>. | |
2049 | </para> | |
2050 | ||
2051 | <para> | |
2052 | See <citerefentry | |
2053 | project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details | |
438311a5 LP |
2054 | about environment variables.</para> |
2055 | ||
2056 | <para>Note that environment variables are not suitable for passing secrets (such as passwords, key material, …) | |
2057 | to service processes. Environment variables set for a unit are exposed to unprivileged clients via D-Bus IPC, | |
2058 | and generally not understood as being data that requires protection. Moreover, environment variables are | |
2059 | propagated down the process tree, including across security boundaries (such as setuid/setgid executables), and | |
2060 | hence might leak to processes that should not have access to the secret data.</para></listitem> | |
b8afec21 LP |
2061 | </varlistentry> |
2062 | ||
2063 | <varlistentry> | |
2064 | <term><varname>EnvironmentFile=</varname></term> | |
2065 | ||
2066 | <listitem><para>Similar to <varname>Environment=</varname> but reads the environment variables from a text | |
2067 | file. The text file should contain new-line-separated variable assignments. Empty lines, lines without an | |
2068 | <literal>=</literal> separator, or lines starting with ; or # will be ignored, which may be used for | |
2069 | commenting. A line ending with a backslash will be concatenated with the following one, allowing multiline | |
2070 | variable definitions. The parser strips leading and trailing whitespace from the values of assignments, unless | |
2071 | you use double quotes (").</para> | |
2072 | ||
69bdb3b1 MS |
2073 | <para><ulink url="https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C escapes</ulink> |
2074 | are supported, but not | |
2075 | <ulink url="https://en.wikipedia.org/wiki/Control_character#In_ASCII">most control characters</ulink>. | |
2076 | <literal>\t</literal> and <literal>\n</literal> can be used to insert tabs and newlines within | |
2077 | <varname>EnvironmentFile=</varname>.</para> | |
2078 | ||
b8afec21 LP |
2079 | <para>The argument passed should be an absolute filename or wildcard expression, optionally prefixed with |
2080 | <literal>-</literal>, which indicates that if the file does not exist, it will not be read and no error or | |
2081 | warning message is logged. This option may be specified more than once in which case all specified files are | |
2082 | read. If the empty string is assigned to this option, the list of file to read is reset, all prior assignments | |
2083 | have no effect.</para> | |
2084 | ||
2085 | <para>The files listed with this directive will be read shortly before the process is executed (more | |
2086 | specifically, after all processes from a previous unit state terminated. This means you can generate these | |
412a6c64 TM |
2087 | files in one unit state, and read it with this option in the next. The files are read from the file |
2088 | system of the service manager, before any file system changes like bind mounts take place).</para> | |
b8afec21 LP |
2089 | |
2090 | <para>Settings from these files override settings made with <varname>Environment=</varname>. If the same | |
2091 | variable is set twice from these files, the files will be read in the order they are specified and the later | |
2092 | setting will override the earlier setting.</para></listitem> | |
2093 | </varlistentry> | |
2094 | ||
2095 | <varlistentry> | |
2096 | <term><varname>PassEnvironment=</varname></term> | |
2097 | ||
2098 | <listitem><para>Pass environment variables set for the system service manager to executed processes. Takes a | |
2099 | space-separated list of variable names. This option may be specified more than once, in which case all listed | |
2100 | variables will be passed. If the empty string is assigned to this option, the list of environment variables to | |
2101 | pass is reset, all prior assignments have no effect. Variables specified that are not set for the system | |
2102 | manager will not be passed and will be silently ignored. Note that this option is only relevant for the system | |
2103 | service manager, as system services by default do not automatically inherit any environment variables set for | |
2104 | the service manager itself. However, in case of the user service manager all environment variables are passed | |
2105 | to the executed processes anyway, hence this option is without effect for the user service manager.</para> | |
2106 | ||
2107 | <para>Variables set for invoked processes due to this setting are subject to being overridden by those | |
2108 | configured with <varname>Environment=</varname> or <varname>EnvironmentFile=</varname>.</para> | |
2109 | ||
69bdb3b1 MS |
2110 | <para><ulink url="https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C escapes</ulink> |
2111 | are supported, but not | |
2112 | <ulink url="https://en.wikipedia.org/wiki/Control_character#In_ASCII">most control characters</ulink>. | |
2113 | <literal>\t</literal> and <literal>\n</literal> can be used to insert tabs and newlines within | |
2114 | <varname>EnvironmentFile=</varname>.</para> | |
2115 | ||
b8afec21 LP |
2116 | <para>Example: |
2117 | <programlisting>PassEnvironment=VAR1 VAR2 VAR3</programlisting> | |
2118 | passes three variables <literal>VAR1</literal>, | |
2119 | <literal>VAR2</literal>, <literal>VAR3</literal> | |
2120 | with the values set for those variables in PID1.</para> | |
2121 | ||
2122 | <para> | |
2123 | See <citerefentry | |
2124 | project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details | |
2125 | about environment variables.</para></listitem> | |
2126 | </varlistentry> | |
2127 | ||
2128 | <varlistentry> | |
2129 | <term><varname>UnsetEnvironment=</varname></term> | |
2130 | ||
2131 | <listitem><para>Explicitly unset environment variable assignments that would normally be passed from the | |
2132 | service manager to invoked processes of this unit. Takes a space-separated list of variable names or variable | |
2133 | assignments. This option may be specified more than once, in which case all listed variables/assignments will | |
2134 | be unset. If the empty string is assigned to this option, the list of environment variables/assignments to | |
2135 | unset is reset. If a variable assignment is specified (that is: a variable name, followed by | |
2136 | <literal>=</literal>, followed by its value), then any environment variable matching this precise assignment is | |
2137 | removed. If a variable name is specified (that is a variable name without any following <literal>=</literal> or | |
2138 | value), then any assignment matching the variable name, regardless of its value is removed. Note that the | |
2139 | effect of <varname>UnsetEnvironment=</varname> is applied as final step when the environment list passed to | |
2140 | executed processes is compiled. That means it may undo assignments from any configuration source, including | |
2141 | assignments made through <varname>Environment=</varname> or <varname>EnvironmentFile=</varname>, inherited from | |
2142 | the system manager's global set of environment variables, inherited via <varname>PassEnvironment=</varname>, | |
2143 | set by the service manager itself (such as <varname>$NOTIFY_SOCKET</varname> and such), or set by a PAM module | |
2144 | (in case <varname>PAMName=</varname> is used).</para> | |
2145 | ||
2146 | <para> | |
2147 | See <citerefentry | |
2148 | project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details | |
2149 | about environment variables.</para></listitem> | |
2150 | </varlistentry> | |
2151 | ||
2152 | </variablelist> | |
2153 | </refsect1> | |
2154 | ||
2155 | <refsect1> | |
2156 | <title>Logging and Standard Input/Output</title> | |
2157 | ||
e0e2ecd5 | 2158 | <variablelist class='unit-directives'> |
b8afec21 LP |
2159 | <varlistentry> |
2160 | ||
2161 | <term><varname>StandardInput=</varname></term> | |
2162 | ||
2163 | <listitem><para>Controls where file descriptor 0 (STDIN) of the executed processes is connected to. Takes one | |
2164 | of <option>null</option>, <option>tty</option>, <option>tty-force</option>, <option>tty-fail</option>, | |
2165 | <option>data</option>, <option>file:<replaceable>path</replaceable></option>, <option>socket</option> or | |
2166 | <option>fd:<replaceable>name</replaceable></option>.</para> | |
2167 | ||
2168 | <para>If <option>null</option> is selected, standard input will be connected to <filename>/dev/null</filename>, | |
2169 | i.e. all read attempts by the process will result in immediate EOF.</para> | |
2170 | ||
2171 | <para>If <option>tty</option> is selected, standard input is connected to a TTY (as configured by | |
2172 | <varname>TTYPath=</varname>, see below) and the executed process becomes the controlling process of the | |
2173 | terminal. If the terminal is already being controlled by another process, the executed process waits until the | |
2174 | current controlling process releases the terminal.</para> | |
2175 | ||
2176 | <para><option>tty-force</option> is similar to <option>tty</option>, but the executed process is forcefully and | |
2177 | immediately made the controlling process of the terminal, potentially removing previous controlling processes | |
2178 | from the terminal.</para> | |
2179 | ||
2180 | <para><option>tty-fail</option> is similar to <option>tty</option>, but if the terminal already has a | |
2181 | controlling process start-up of the executed process fails.</para> | |
2182 | ||
2183 | <para>The <option>data</option> option may be used to configure arbitrary textual or binary data to pass via | |
2184 | standard input to the executed process. The data to pass is configured via | |
2185 | <varname>StandardInputText=</varname>/<varname>StandardInputData=</varname> (see below). Note that the actual | |
2186 | file descriptor type passed (memory file, regular file, UNIX pipe, …) might depend on the kernel and available | |
2187 | privileges. In any case, the file descriptor is read-only, and when read returns the specified data followed by | |
2188 | EOF.</para> | |
2189 | ||
2190 | <para>The <option>file:<replaceable>path</replaceable></option> option may be used to connect a specific file | |
2191 | system object to standard input. An absolute path following the <literal>:</literal> character is expected, | |
2192 | which may refer to a regular file, a FIFO or special file. If an <constant>AF_UNIX</constant> socket in the | |
2193 | file system is specified, a stream socket is connected to it. The latter is useful for connecting standard | |
2194 | input of processes to arbitrary system services.</para> | |
2195 | ||
2196 | <para>The <option>socket</option> option is valid in socket-activated services only, and requires the relevant | |
2197 | socket unit file (see | |
2198 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details) | |
2199 | to have <varname>Accept=yes</varname> set, or to specify a single socket only. If this option is set, standard | |
2200 | input will be connected to the socket the service was activated from, which is primarily useful for | |
2201 | compatibility with daemons designed for use with the traditional <citerefentry | |
2202 | project='freebsd'><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry> socket activation | |
2203 | daemon.</para> | |
2204 | ||
2205 | <para>The <option>fd:<replaceable>name</replaceable></option> option connects standard input to a specific, | |
2206 | named file descriptor provided by a socket unit. The name may be specified as part of this option, following a | |
2207 | <literal>:</literal> character (e.g. <literal>fd:foobar</literal>). If no name is specified, the name | |
2208 | <literal>stdin</literal> is implied (i.e. <literal>fd</literal> is equivalent to <literal>fd:stdin</literal>). | |
2209 | At least one socket unit defining the specified name must be provided via the <varname>Sockets=</varname> | |
2210 | option, and the file descriptor name may differ from the name of its containing socket unit. If multiple | |
2211 | matches are found, the first one will be used. See <varname>FileDescriptorName=</varname> in | |
2212 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more | |
2213 | details about named file descriptors and their ordering.</para> | |
2214 | ||
8fa2cd83 | 2215 | <para>This setting defaults to <option>null</option>.</para></listitem> |
b8afec21 LP |
2216 | </varlistentry> |
2217 | ||
2218 | <varlistentry> | |
2219 | <term><varname>StandardOutput=</varname></term> | |
2220 | ||
d58b613b | 2221 | <listitem><para>Controls where file descriptor 1 (stdout) of the executed processes is connected |
eedaf7f3 LP |
2222 | to. Takes one of <option>inherit</option>, <option>null</option>, <option>tty</option>, |
2223 | <option>journal</option>, <option>kmsg</option>, <option>journal+console</option>, | |
2224 | <option>kmsg+console</option>, <option>file:<replaceable>path</replaceable></option>, | |
2225 | <option>append:<replaceable>path</replaceable></option>, <option>socket</option> or | |
2226 | <option>fd:<replaceable>name</replaceable></option>.</para> | |
b8afec21 LP |
2227 | |
2228 | <para><option>inherit</option> duplicates the file descriptor of standard input for standard output.</para> | |
2229 | ||
2230 | <para><option>null</option> connects standard output to <filename>/dev/null</filename>, i.e. everything written | |
2231 | to it will be lost.</para> | |
2232 | ||
2233 | <para><option>tty</option> connects standard output to a tty (as configured via <varname>TTYPath=</varname>, | |
2234 | see below). If the TTY is used for output only, the executed process will not become the controlling process of | |
2235 | the terminal, and will not fail or wait for other processes to release the terminal.</para> | |
2236 | ||
eedaf7f3 LP |
2237 | <para><option>journal</option> connects standard output with the journal, which is accessible via |
2238 | <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Note | |
2239 | that everything that is written to kmsg (see below) is implicitly stored in the journal as well, the | |
2240 | specific option listed below is hence a superset of this one. (Also note that any external, | |
2241 | additional syslog daemons receive their log data from the journal, too, hence this is the option to | |
2242 | use when logging shall be processed with such a daemon.)</para> | |
b8afec21 LP |
2243 | |
2244 | <para><option>kmsg</option> connects standard output with the kernel log buffer which is accessible via | |
2245 | <citerefentry project='man-pages'><refentrytitle>dmesg</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
2246 | in addition to the journal. The journal daemon might be configured to send all logs to kmsg anyway, in which | |
2247 | case this option is no different from <option>journal</option>.</para> | |
2248 | ||
eedaf7f3 LP |
2249 | <para><option>journal+console</option> and <option>kmsg+console</option> work in a similar way as the |
2250 | two options above but copy the output to the system console as well.</para> | |
b8afec21 LP |
2251 | |
2252 | <para>The <option>file:<replaceable>path</replaceable></option> option may be used to connect a specific file | |
2253 | system object to standard output. The semantics are similar to the same option of | |
566b7d23 ZD |
2254 | <varname>StandardInput=</varname>, see above. If <replaceable>path</replaceable> refers to a regular file |
2255 | on the filesystem, it is opened (created if it doesn't exist yet) for writing at the beginning of the file, | |
2256 | but without truncating it. | |
2257 | If standard input and output are directed to the same file path, it is opened only once, for reading as well | |
2258 | as writing and duplicated. This is particularly useful when the specified path refers to an | |
2259 | <constant>AF_UNIX</constant> socket in the file system, as in that case only a | |
b8afec21 LP |
2260 | single stream connection is created for both input and output.</para> |
2261 | ||
e9dd6984 ZJS |
2262 | <para><option>append:<replaceable>path</replaceable></option> is similar to |
2263 | <option>file:<replaceable>path</replaceable></option> above, but it opens the file in append mode. | |
2264 | </para> | |
566b7d23 | 2265 | |
b8afec21 LP |
2266 | <para><option>socket</option> connects standard output to a socket acquired via socket activation. The |
2267 | semantics are similar to the same option of <varname>StandardInput=</varname>, see above.</para> | |
2268 | ||
2269 | <para>The <option>fd:<replaceable>name</replaceable></option> option connects standard output to a specific, | |
2270 | named file descriptor provided by a socket unit. A name may be specified as part of this option, following a | |
2271 | <literal>:</literal> character (e.g. <literal>fd:foobar</literal>). If no name is specified, the name | |
2272 | <literal>stdout</literal> is implied (i.e. <literal>fd</literal> is equivalent to | |
2273 | <literal>fd:stdout</literal>). At least one socket unit defining the specified name must be provided via the | |
2274 | <varname>Sockets=</varname> option, and the file descriptor name may differ from the name of its containing | |
2275 | socket unit. If multiple matches are found, the first one will be used. See | |
2276 | <varname>FileDescriptorName=</varname> in | |
2277 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more | |
2278 | details about named descriptors and their ordering.</para> | |
2279 | ||
eedaf7f3 LP |
2280 | <para>If the standard output (or error output, see below) of a unit is connected to the journal or |
2281 | the kernel log buffer, the unit will implicitly gain a dependency of type <varname>After=</varname> | |
2282 | on <filename>systemd-journald.socket</filename> (also see the "Implicit Dependencies" section | |
2283 | above). Also note that in this case stdout (or stderr, see below) will be an | |
2284 | <constant>AF_UNIX</constant> stream socket, and not a pipe or FIFO that can be re-opened. This means | |
2285 | when executing shell scripts the construct <command>echo "hello" > /dev/stderr</command> for | |
2286 | writing text to stderr will not work. To mitigate this use the construct <command>echo "hello" | |
2287 | >&2</command> instead, which is mostly equivalent and avoids this pitfall.</para> | |
b8afec21 LP |
2288 | |
2289 | <para>This setting defaults to the value set with <varname>DefaultStandardOutput=</varname> in | |
2290 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, which | |
2291 | defaults to <option>journal</option>. Note that setting this parameter might result in additional dependencies | |
2292 | to be added to the unit (see above).</para></listitem> | |
2293 | </varlistentry> | |
2294 | ||
2295 | <varlistentry> | |
2296 | <term><varname>StandardError=</varname></term> | |
2297 | ||
d58b613b | 2298 | <listitem><para>Controls where file descriptor 2 (stderr) of the executed processes is connected to. The |
b8afec21 LP |
2299 | available options are identical to those of <varname>StandardOutput=</varname>, with some exceptions: if set to |
2300 | <option>inherit</option> the file descriptor used for standard output is duplicated for standard error, while | |
2301 | <option>fd:<replaceable>name</replaceable></option> will use a default file descriptor name of | |
2302 | <literal>stderr</literal>.</para> | |
2303 | ||
2304 | <para>This setting defaults to the value set with <varname>DefaultStandardError=</varname> in | |
2305 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, which | |
2306 | defaults to <option>inherit</option>. Note that setting this parameter might result in additional dependencies | |
2307 | to be added to the unit (see above).</para></listitem> | |
2308 | </varlistentry> | |
2309 | ||
2310 | <varlistentry> | |
2311 | <term><varname>StandardInputText=</varname></term> | |
2312 | <term><varname>StandardInputData=</varname></term> | |
2313 | ||
2314 | <listitem><para>Configures arbitrary textual or binary data to pass via file descriptor 0 (STDIN) to the | |
2315 | executed processes. These settings have no effect unless <varname>StandardInput=</varname> is set to | |
2316 | <option>data</option>. Use this option to embed process input data directly in the unit file.</para> | |
2317 | ||
2318 | <para><varname>StandardInputText=</varname> accepts arbitrary textual data. C-style escapes for special | |
2319 | characters as well as the usual <literal>%</literal>-specifiers are resolved. Each time this setting is used | |
1b2ad5d9 | 2320 | the specified text is appended to the per-unit data buffer, followed by a newline character (thus every use |
b8afec21 LP |
2321 | appends a new line to the end of the buffer). Note that leading and trailing whitespace of lines configured |
2322 | with this option is removed. If an empty line is specified the buffer is cleared (hence, in order to insert an | |
2323 | empty line, add an additional <literal>\n</literal> to the end or beginning of a line).</para> | |
2324 | ||
2325 | <para><varname>StandardInputData=</varname> accepts arbitrary binary data, encoded in <ulink | |
2326 | url="https://tools.ietf.org/html/rfc2045#section-6.8">Base64</ulink>. No escape sequences or specifiers are | |
2327 | resolved. Any whitespace in the encoded version is ignored during decoding.</para> | |
2328 | ||
2329 | <para>Note that <varname>StandardInputText=</varname> and <varname>StandardInputData=</varname> operate on the | |
2330 | same data buffer, and may be mixed in order to configure both binary and textual data for the same input | |
2331 | stream. The textual or binary data is joined strictly in the order the settings appear in the unit | |
2332 | file. Assigning an empty string to either will reset the data buffer.</para> | |
2333 | ||
2334 | <para>Please keep in mind that in order to maintain readability long unit file settings may be split into | |
2335 | multiple lines, by suffixing each line (except for the last) with a <literal>\</literal> character (see | |
2336 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for | |
2337 | details). This is particularly useful for large data configured with these two options. Example:</para> | |
2338 | ||
2339 | <programlisting>… | |
2340 | StandardInput=data | |
2341 | StandardInputData=SWNrIHNpdHplIGRhIHVuJyBlc3NlIEtsb3BzLAp1ZmYgZWVtYWwga2xvcHAncy4KSWNrIGtpZWtl \ | |
2342 | LCBzdGF1bmUsIHd1bmRyZSBtaXIsCnVmZiBlZW1hbCBqZWh0IHNlIHVmZiBkaWUgVMO8ci4KTmFu \ | |
2343 | dSwgZGVuayBpY2ssIGljayBkZW5rIG5hbnUhCkpldHogaXNzZSB1ZmYsIGVyc2NodCB3YXIgc2Ug \ | |
2344 | enUhCkljayBqZWhlIHJhdXMgdW5kIGJsaWNrZSDigJQKdW5kIHdlciBzdGVodCBkcmF1w59lbj8g \ | |
2345 | SWNrZSEK | |
2346 | …</programlisting></listitem> | |
798d3a52 ZJS |
2347 | </varlistentry> |
2348 | ||
2349 | <varlistentry> | |
b8afec21 | 2350 | <term><varname>LogLevelMax=</varname></term> |
142bd808 | 2351 | |
b8afec21 LP |
2352 | <listitem><para>Configures filtering by log level of log messages generated by this unit. Takes a |
2353 | <command>syslog</command> log level, one of <option>emerg</option> (lowest log level, only highest priority | |
2354 | messages), <option>alert</option>, <option>crit</option>, <option>err</option>, <option>warning</option>, | |
2355 | <option>notice</option>, <option>info</option>, <option>debug</option> (highest log level, also lowest priority | |
2356 | messages). See <citerefentry | |
2357 | project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> for | |
2358 | details. By default no filtering is applied (i.e. the default maximum log level is <option>debug</option>). Use | |
2359 | this option to configure the logging system to drop log messages of a specific service above the specified | |
2360 | level. For example, set <varname>LogLevelMax=</varname><option>info</option> in order to turn off debug logging | |
1b2ad5d9 | 2361 | of a particularly chatty unit. Note that the configured level is applied to any log messages written by any |
b8afec21 LP |
2362 | of the processes belonging to this unit, sent via any supported logging protocol. The filtering is applied |
2363 | early in the logging pipeline, before any kind of further processing is done. Moreover, messages which pass | |
2364 | through this filter successfully might still be dropped by filters applied at a later stage in the logging | |
2365 | subsystem. For example, <varname>MaxLevelStore=</varname> configured in | |
2366 | <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> might | |
2367 | prohibit messages of higher log levels to be stored on disk, even though the per-unit | |
2368 | <varname>LogLevelMax=</varname> permitted it to be processed.</para></listitem> | |
798d3a52 ZJS |
2369 | </varlistentry> |
2370 | ||
add00535 | 2371 | <varlistentry> |
b8afec21 | 2372 | <term><varname>LogExtraFields=</varname></term> |
add00535 | 2373 | |
db11487d ZJS |
2374 | <listitem><para>Configures additional log metadata fields to include in all log records generated by |
2375 | processes associated with this unit. This setting takes one or more journal field assignments in the | |
2376 | format <literal>FIELD=VALUE</literal> separated by whitespace. See | |
2377 | <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
2378 | for details on the journal field concept. Even though the underlying journal implementation permits | |
2379 | binary field values, this setting accepts only valid UTF-8 values. To include space characters in a | |
2380 | journal field value, enclose the assignment in double quotes ("). <!-- " fake closing quote for emacs--> | |
2381 | The usual specifiers are expanded in all assignments (see below). Note that this setting is not only | |
2382 | useful for attaching additional metadata to log records of a unit, but given that all fields and | |
2383 | values are indexed may also be used to implement cross-unit log record matching. Assign an empty | |
2384 | string to reset the list.</para></listitem> | |
add00535 LP |
2385 | </varlistentry> |
2386 | ||
90fc172e AZ |
2387 | <varlistentry> |
2388 | <term><varname>LogRateLimitIntervalSec=</varname></term> | |
2389 | <term><varname>LogRateLimitBurst=</varname></term> | |
2390 | ||
2391 | <listitem><para>Configures the rate limiting that is applied to messages generated by this unit. If, in the | |
2392 | time interval defined by <varname>LogRateLimitIntervalSec=</varname>, more messages than specified in | |
2393 | <varname>LogRateLimitBurst=</varname> are logged by a service, all further messages within the interval are | |
2394 | dropped until the interval is over. A message about the number of dropped messages is generated. The time | |
2395 | specification for <varname>LogRateLimitIntervalSec=</varname> may be specified in the following units: "s", | |
2396 | "min", "h", "ms", "us" (see | |
2397 | <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details). | |
2398 | The default settings are set by <varname>RateLimitIntervalSec=</varname> and <varname>RateLimitBurst=</varname> | |
2399 | configured in <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. | |
2400 | </para></listitem> | |
2401 | </varlistentry> | |
2402 | ||
5b0a76d1 LP |
2403 | <varlistentry> |
2404 | <term><varname>LogNamespace=</varname></term> | |
2405 | ||
2406 | <listitem><para>Run the unit's processes in the specified journal namespace. Expects a short | |
2407 | user-defined string identifying the namespace. If not used the processes of the service are run in | |
2408 | the default journal namespace, i.e. their log stream is collected and processed by | |
2409 | <filename>systemd-journald.service</filename>. If this option is used any log data generated by | |
2410 | processes of this unit (regardless if via the <function>syslog()</function>, journal native logging | |
2411 | or stdout/stderr logging) is collected and processed by an instance of the | |
2412 | <filename>systemd-journald@.service</filename> template unit, which manages the specified | |
2413 | namespace. The log data is stored in a data store independent from the default log namespace's data | |
2414 | store. See | |
2415 | <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
2416 | for details about journal namespaces.</para> | |
2417 | ||
2418 | <para>Internally, journal namespaces are implemented through Linux mount namespacing and | |
2419 | over-mounting the directory that contains the relevant <constant>AF_UNIX</constant> sockets used for | |
2420 | logging in the unit's mount namespace. Since mount namespaces are used this setting disconnects | |
2421 | propagation of mounts from the unit's processes to the host, similar to how | |
2422 | <varname>ReadOnlyPaths=</varname> and similar settings (see above) work. Journal namespaces may hence | |
2423 | not be used for services that need to establish mount points on the host.</para> | |
2424 | ||
2425 | <para>When this option is used the unit will automatically gain ordering and requirement dependencies | |
2426 | on the two socket units associated with the <filename>systemd-journald@.service</filename> instance | |
2427 | so that they are automatically established prior to the unit starting up. Note that when this option | |
2428 | is used log output of this service does not appear in the regular | |
2429 | <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
2430 | output, unless the <option>--namespace=</option> option is used.</para></listitem> | |
2431 | </varlistentry> | |
2432 | ||
798d3a52 | 2433 | <varlistentry> |
b8afec21 | 2434 | <term><varname>SyslogIdentifier=</varname></term> |
798d3a52 | 2435 | |
eedaf7f3 LP |
2436 | <listitem><para>Sets the process name ("<command>syslog</command> tag") to prefix log lines sent to |
2437 | the logging system or the kernel log buffer with. If not set, defaults to the process name of the | |
2438 | executed process. This option is only useful when <varname>StandardOutput=</varname> or | |
2439 | <varname>StandardError=</varname> are set to <option>journal</option> or <option>kmsg</option> (or to | |
2440 | the same settings in combination with <option>+console</option>) and only applies to log messages | |
2441 | written to stdout or stderr.</para></listitem> | |
798d3a52 ZJS |
2442 | </varlistentry> |
2443 | ||
2444 | <varlistentry> | |
b8afec21 | 2445 | <term><varname>SyslogFacility=</varname></term> |
78e864e5 | 2446 | |
b8afec21 LP |
2447 | <listitem><para>Sets the <command>syslog</command> facility identifier to use when logging. One of |
2448 | <option>kern</option>, <option>user</option>, <option>mail</option>, <option>daemon</option>, | |
2449 | <option>auth</option>, <option>syslog</option>, <option>lpr</option>, <option>news</option>, | |
2450 | <option>uucp</option>, <option>cron</option>, <option>authpriv</option>, <option>ftp</option>, | |
2451 | <option>local0</option>, <option>local1</option>, <option>local2</option>, <option>local3</option>, | |
eedaf7f3 LP |
2452 | <option>local4</option>, <option>local5</option>, <option>local6</option> or |
2453 | <option>local7</option>. See <citerefentry | |
2454 | project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> for | |
2455 | details. This option is only useful when <varname>StandardOutput=</varname> or | |
2456 | <varname>StandardError=</varname> are set to <option>journal</option> or <option>kmsg</option> (or to | |
2457 | the same settings in combination with <option>+console</option>), and only applies to log messages | |
2458 | written to stdout or stderr. Defaults to <option>daemon</option>.</para></listitem> | |
78e864e5 TM |
2459 | </varlistentry> |
2460 | ||
b1edf445 | 2461 | <varlistentry> |
b8afec21 | 2462 | <term><varname>SyslogLevel=</varname></term> |
b1edf445 | 2463 | |
b8afec21 LP |
2464 | <listitem><para>The default <command>syslog</command> log level to use when logging to the logging system or |
2465 | the kernel log buffer. One of <option>emerg</option>, <option>alert</option>, <option>crit</option>, | |
2466 | <option>err</option>, <option>warning</option>, <option>notice</option>, <option>info</option>, | |
2467 | <option>debug</option>. See <citerefentry | |
2468 | project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> for | |
2469 | details. This option is only useful when <varname>StandardOutput=</varname> or | |
eedaf7f3 | 2470 | <varname>StandardError=</varname> are set to <option>journal</option> or |
b8afec21 LP |
2471 | <option>kmsg</option> (or to the same settings in combination with <option>+console</option>), and only applies |
2472 | to log messages written to stdout or stderr. Note that individual lines output by executed processes may be | |
2473 | prefixed with a different log level which can be used to override the default log level specified here. The | |
2474 | interpretation of these prefixes may be disabled with <varname>SyslogLevelPrefix=</varname>, see below. For | |
2475 | details, see <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
2476 | Defaults to <option>info</option>.</para></listitem> | |
78e864e5 TM |
2477 | </varlistentry> |
2478 | ||
2479 | <varlistentry> | |
b8afec21 | 2480 | <term><varname>SyslogLevelPrefix=</varname></term> |
4a628360 | 2481 | |
b8afec21 | 2482 | <listitem><para>Takes a boolean argument. If true and <varname>StandardOutput=</varname> or |
eedaf7f3 LP |
2483 | <varname>StandardError=</varname> are set to <option>journal</option> or <option>kmsg</option> (or to |
2484 | the same settings in combination with <option>+console</option>), log lines written by the executed | |
2485 | process that are prefixed with a log level will be processed with this log level set but the prefix | |
2486 | removed. If set to false, the interpretation of these prefixes is disabled and the logged lines are | |
2487 | passed on as-is. This only applies to log messages written to stdout or stderr. For details about | |
2488 | this prefixing see | |
2489 | <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
b8afec21 LP |
2490 | Defaults to true.</para></listitem> |
2491 | </varlistentry> | |
fdfcb946 | 2492 | |
b8afec21 LP |
2493 | <varlistentry> |
2494 | <term><varname>TTYPath=</varname></term> | |
4a628360 | 2495 | |
b8afec21 LP |
2496 | <listitem><para>Sets the terminal device node to use if standard input, output, or error are connected to a TTY |
2497 | (see above). Defaults to <filename>/dev/console</filename>.</para></listitem> | |
2498 | </varlistentry> | |
23a7448e | 2499 | |
b8afec21 LP |
2500 | <varlistentry> |
2501 | <term><varname>TTYReset=</varname></term> | |
3536f49e | 2502 | |
b8afec21 LP |
2503 | <listitem><para>Reset the terminal device specified with <varname>TTYPath=</varname> before and after |
2504 | execution. Defaults to <literal>no</literal>.</para></listitem> | |
3536f49e YW |
2505 | </varlistentry> |
2506 | ||
189cd8c2 | 2507 | <varlistentry> |
b8afec21 | 2508 | <term><varname>TTYVHangup=</varname></term> |
189cd8c2 | 2509 | |
b8afec21 LP |
2510 | <listitem><para>Disconnect all clients which have opened the terminal device specified with |
2511 | <varname>TTYPath=</varname> before and after execution. Defaults to <literal>no</literal>.</para></listitem> | |
189cd8c2 ZJS |
2512 | </varlistentry> |
2513 | ||
53f47dfc | 2514 | <varlistentry> |
b8afec21 | 2515 | <term><varname>TTYVTDisallocate=</varname></term> |
53f47dfc | 2516 | |
b8afec21 LP |
2517 | <listitem><para>If the terminal device specified with <varname>TTYPath=</varname> is a virtual console |
2518 | terminal, try to deallocate the TTY before and after execution. This ensures that the screen and scrollback | |
2519 | buffer is cleared. Defaults to <literal>no</literal>.</para></listitem> | |
189cd8c2 | 2520 | </varlistentry> |
b8afec21 LP |
2521 | </variablelist> |
2522 | </refsect1> | |
2523 | ||
2524 | <refsect1> | |
2525 | <title>System V Compatibility</title> | |
e0e2ecd5 | 2526 | <variablelist class='unit-directives'> |
189cd8c2 | 2527 | |
f3e43635 | 2528 | <varlistentry> |
b8afec21 | 2529 | <term><varname>UtmpIdentifier=</varname></term> |
f3e43635 | 2530 | |
b8afec21 LP |
2531 | <listitem><para>Takes a four character identifier string for an <citerefentry |
2532 | project='man-pages'><refentrytitle>utmp</refentrytitle><manvolnum>5</manvolnum></citerefentry> and wtmp entry | |
2533 | for this service. This should only be set for services such as <command>getty</command> implementations (such | |
2534 | as <citerefentry | |
2535 | project='die-net'><refentrytitle>agetty</refentrytitle><manvolnum>8</manvolnum></citerefentry>) where utmp/wtmp | |
2536 | entries must be created and cleared before and after execution, or for services that shall be executed as if | |
2537 | they were run by a <command>getty</command> process (see below). If the configured string is longer than four | |
2538 | characters, it is truncated and the terminal four characters are used. This setting interprets %I style string | |
2539 | replacements. This setting is unset by default, i.e. no utmp/wtmp entries are created or cleaned up for this | |
2540 | service.</para></listitem> | |
f3e43635 TM |
2541 | </varlistentry> |
2542 | ||
f4170c67 | 2543 | <varlistentry> |
b8afec21 | 2544 | <term><varname>UtmpMode=</varname></term> |
f4170c67 | 2545 | |
b8afec21 LP |
2546 | <listitem><para>Takes one of <literal>init</literal>, <literal>login</literal> or <literal>user</literal>. If |
2547 | <varname>UtmpIdentifier=</varname> is set, controls which type of <citerefentry | |
2548 | project='man-pages'><refentrytitle>utmp</refentrytitle><manvolnum>5</manvolnum></citerefentry>/wtmp entries | |
2549 | for this service are generated. This setting has no effect unless <varname>UtmpIdentifier=</varname> is set | |
2550 | too. If <literal>init</literal> is set, only an <constant>INIT_PROCESS</constant> entry is generated and the | |
2551 | invoked process must implement a <command>getty</command>-compatible utmp/wtmp logic. If | |
2552 | <literal>login</literal> is set, first an <constant>INIT_PROCESS</constant> entry, followed by a | |
2553 | <constant>LOGIN_PROCESS</constant> entry is generated. In this case, the invoked process must implement a | |
2554 | <citerefentry | |
2555 | project='die-net'><refentrytitle>login</refentrytitle><manvolnum>1</manvolnum></citerefentry>-compatible | |
2556 | utmp/wtmp logic. If <literal>user</literal> is set, first an <constant>INIT_PROCESS</constant> entry, then a | |
2557 | <constant>LOGIN_PROCESS</constant> entry and finally a <constant>USER_PROCESS</constant> entry is | |
2558 | generated. In this case, the invoked process may be any process that is suitable to be run as session | |
2559 | leader. Defaults to <literal>init</literal>.</para></listitem> | |
f4170c67 LP |
2560 | </varlistentry> |
2561 | ||
798d3a52 ZJS |
2562 | </variablelist> |
2563 | </refsect1> | |
2564 | ||
2565 | <refsect1> | |
2566 | <title>Environment variables in spawned processes</title> | |
2567 | ||
00819cc1 LP |
2568 | <para>Processes started by the service manager are executed with an environment variable block assembled from |
2569 | multiple sources. Processes started by the system service manager generally do not inherit environment variables | |
2570 | set for the service manager itself (but this may be altered via <varname>PassEnvironment=</varname>), but processes | |
2571 | started by the user service manager instances generally do inherit all environment variables set for the service | |
2572 | manager itself.</para> | |
2573 | ||
2574 | <para>For each invoked process the list of environment variables set is compiled from the following sources:</para> | |
2575 | ||
2576 | <itemizedlist> | |
2577 | <listitem><para>Variables globally configured for the service manager, using the | |
2578 | <varname>DefaultEnvironment=</varname> setting in | |
2579 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, the kernel command line option <varname>systemd.setenv=</varname> (see | |
2580 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>) or via | |
2581 | <command>systemctl set-environment</command> (see <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>).</para></listitem> | |
2582 | ||
2583 | <listitem><para>Variables defined by the service manager itself (see the list below)</para></listitem> | |
2584 | ||
2585 | <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> | |
2586 | ||
2587 | <listitem><para>Variables set via <varname>Environment=</varname> in the unit file</para></listitem> | |
2588 | ||
606df9a5 | 2589 | <listitem><para>Variables read from files specified via <varname>EnvironmentFile=</varname> in the unit file</para></listitem> |
00819cc1 | 2590 | |
46b07329 LP |
2591 | <listitem><para>Variables set by any PAM modules in case <varname>PAMName=</varname> is in effect, |
2592 | cf. <citerefentry | |
2593 | project='man-pages'><refentrytitle>pam_env</refentrytitle><manvolnum>8</manvolnum></citerefentry></para></listitem> | |
00819cc1 LP |
2594 | </itemizedlist> |
2595 | ||
2596 | <para>If the same environment variables are set by multiple of these sources, the later source — according to the | |
2597 | order of the list above — wins. Note that as final step all variables listed in | |
2598 | <varname>UnsetEnvironment=</varname> are removed again from the compiled environment variable list, immediately | |
2599 | before it is passed to the executed process.</para> | |
2600 | ||
e9dd6984 | 2601 | <para>The following environment variables are set or propagated by the service manager for each invoked |
46b07329 | 2602 | process:</para> |
798d3a52 ZJS |
2603 | |
2604 | <variablelist class='environment-variables'> | |
2605 | <varlistentry> | |
2606 | <term><varname>$PATH</varname></term> | |
2607 | ||
db11487d ZJS |
2608 | <listitem><para>Colon-separated list of directories to use when launching |
2609 | executables. <command>systemd</command> uses a fixed value of | |
2610 | <literal><filename>/usr/local/sbin</filename>:<filename>/usr/local/bin</filename>:<filename>/usr/sbin</filename>:<filename>/usr/bin</filename></literal> | |
2611 | in the system manager. When compiled for systems with "unmerged /usr" (<filename>/bin</filename> is | |
2612 | not a symlink to <filename>/usr/bin</filename>), | |
2613 | <literal>:<filename>/sbin</filename>:<filename>/bin</filename></literal> is appended. In case of the | |
3602ca6f ZJS |
2614 | the user manager, a different path may be configured by the distribution. It is recommended to not |
2615 | rely on the order of entries, and have only one program with a given name in | |
2616 | <varname>$PATH</varname>.</para></listitem> | |
798d3a52 ZJS |
2617 | </varlistentry> |
2618 | ||
2619 | <varlistentry> | |
2620 | <term><varname>$LANG</varname></term> | |
2621 | ||
2622 | <listitem><para>Locale. Can be set in | |
3ba3a79d | 2623 | <citerefentry project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
798d3a52 ZJS |
2624 | or on the kernel command line (see |
2625 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
2626 | and | |
2627 | <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>). | |
2628 | </para></listitem> | |
2629 | </varlistentry> | |
2630 | ||
2631 | <varlistentry> | |
2632 | <term><varname>$USER</varname></term> | |
2633 | <term><varname>$LOGNAME</varname></term> | |
2634 | <term><varname>$HOME</varname></term> | |
2635 | <term><varname>$SHELL</varname></term> | |
2636 | ||
2637 | <listitem><para>User name (twice), home directory, and the | |
23deef88 LP |
2638 | login shell. The variables are set for the units that have |
2639 | <varname>User=</varname> set, which includes user | |
2640 | <command>systemd</command> instances. See | |
3ba3a79d | 2641 | <citerefentry project='die-net'><refentrytitle>passwd</refentrytitle><manvolnum>5</manvolnum></citerefentry>. |
798d3a52 ZJS |
2642 | </para></listitem> |
2643 | </varlistentry> | |
2644 | ||
4b58153d LP |
2645 | <varlistentry> |
2646 | <term><varname>$INVOCATION_ID</varname></term> | |
2647 | ||
2648 | <listitem><para>Contains a randomized, unique 128bit ID identifying each runtime cycle of the unit, formatted | |
2649 | as 32 character hexadecimal string. A new ID is assigned each time the unit changes from an inactive state into | |
2650 | an activating or active state, and may be used to identify this specific runtime cycle, in particular in data | |
2651 | stored offline, such as the journal. The same ID is passed to all processes run as part of the | |
2652 | unit.</para></listitem> | |
2653 | </varlistentry> | |
2654 | ||
798d3a52 ZJS |
2655 | <varlistentry> |
2656 | <term><varname>$XDG_RUNTIME_DIR</varname></term> | |
2657 | ||
46b07329 LP |
2658 | <listitem><para>The directory to use for runtime objects (such as IPC objects) and volatile state. Set for all |
2659 | services run by the user <command>systemd</command> instance, as well as any system services that use | |
2660 | <varname>PAMName=</varname> with a PAM stack that includes <command>pam_systemd</command>. See below and | |
2661 | <citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry> for more | |
2662 | information.</para></listitem> | |
798d3a52 ZJS |
2663 | </varlistentry> |
2664 | ||
1f6597a8 ZJS |
2665 | <varlistentry> |
2666 | <term><varname>$RUNTIME_DIRECTORY</varname></term> | |
2667 | <term><varname>$STATE_DIRECTORY</varname></term> | |
2668 | <term><varname>$CACHE_DIRECTORY</varname></term> | |
2669 | <term><varname>$LOGS_DIRECTORY</varname></term> | |
2670 | <term><varname>$CONFIGURATION_DIRECTORY</varname></term> | |
2671 | ||
e9dd6984 | 2672 | <listitem><para>Absolute paths to the directories defined with |
1f6597a8 ZJS |
2673 | <varname>RuntimeDirectory=</varname>, <varname>StateDirectory=</varname>, |
2674 | <varname>CacheDirectory=</varname>, <varname>LogsDirectory=</varname>, and | |
2675 | <varname>ConfigurationDirectory=</varname> when those settings are used.</para> | |
2676 | </listitem> | |
2677 | </varlistentry> | |
2678 | ||
798d3a52 ZJS |
2679 | <varlistentry> |
2680 | <term><varname>$MAINPID</varname></term> | |
2681 | ||
2dd67817 | 2682 | <listitem><para>The PID of the unit's main process if it is |
798d3a52 ZJS |
2683 | known. This is only set for control processes as invoked by |
2684 | <varname>ExecReload=</varname> and similar. </para></listitem> | |
2685 | </varlistentry> | |
2686 | ||
2687 | <varlistentry> | |
2688 | <term><varname>$MANAGERPID</varname></term> | |
2689 | ||
2690 | <listitem><para>The PID of the user <command>systemd</command> | |
2691 | instance, set for processes spawned by it. </para></listitem> | |
2692 | </varlistentry> | |
2693 | ||
2694 | <varlistentry> | |
2695 | <term><varname>$LISTEN_FDS</varname></term> | |
2696 | <term><varname>$LISTEN_PID</varname></term> | |
5c019cf2 | 2697 | <term><varname>$LISTEN_FDNAMES</varname></term> |
798d3a52 ZJS |
2698 | |
2699 | <listitem><para>Information about file descriptors passed to a | |
2700 | service for socket activation. See | |
2701 | <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
2702 | </para></listitem> | |
2703 | </varlistentry> | |
2704 | ||
5c019cf2 EV |
2705 | <varlistentry> |
2706 | <term><varname>$NOTIFY_SOCKET</varname></term> | |
2707 | ||
2708 | <listitem><para>The socket | |
2709 | <function>sd_notify()</function> talks to. See | |
2710 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
2711 | </para></listitem> | |
2712 | </varlistentry> | |
2713 | ||
2714 | <varlistentry> | |
2715 | <term><varname>$WATCHDOG_PID</varname></term> | |
2716 | <term><varname>$WATCHDOG_USEC</varname></term> | |
2717 | ||
2718 | <listitem><para>Information about watchdog keep-alive notifications. See | |
2719 | <citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
2720 | </para></listitem> | |
2721 | </varlistentry> | |
2722 | ||
798d3a52 ZJS |
2723 | <varlistentry> |
2724 | <term><varname>$TERM</varname></term> | |
2725 | ||
2726 | <listitem><para>Terminal type, set only for units connected to | |
2727 | a terminal (<varname>StandardInput=tty</varname>, | |
2728 | <varname>StandardOutput=tty</varname>, or | |
2729 | <varname>StandardError=tty</varname>). See | |
2730 | <citerefentry project='man-pages'><refentrytitle>termcap</refentrytitle><manvolnum>5</manvolnum></citerefentry>. | |
2731 | </para></listitem> | |
2732 | </varlistentry> | |
7bce046b | 2733 | |
6551cf2d LP |
2734 | <varlistentry> |
2735 | <term><varname>$LOG_NAMESPACE</varname></term> | |
2736 | ||
2737 | <listitem><para>If the <varname>LogNamespace=</varname> service setting is used, contains name of the | |
2738 | selected logging namespace.</para></listitem> | |
2739 | </varlistentry> | |
2740 | ||
7bce046b LP |
2741 | <varlistentry> |
2742 | <term><varname>$JOURNAL_STREAM</varname></term> | |
2743 | ||
2744 | <listitem><para>If the standard output or standard error output of the executed processes are connected to the | |
2745 | journal (for example, by setting <varname>StandardError=journal</varname>) <varname>$JOURNAL_STREAM</varname> | |
2746 | contains the device and inode numbers of the connection file descriptor, formatted in decimal, separated by a | |
2747 | colon (<literal>:</literal>). This permits invoked processes to safely detect whether their standard output or | |
2748 | standard error output are connected to the journal. The device and inode numbers of the file descriptors should | |
2749 | be compared with the values set in the environment variable to determine whether the process output is still | |
2750 | connected to the journal. Note that it is generally not sufficient to only check whether | |
2751 | <varname>$JOURNAL_STREAM</varname> is set at all as services might invoke external processes replacing their | |
2752 | standard output or standard error output, without unsetting the environment variable.</para> | |
2753 | ||
ab2116b1 LP |
2754 | <para>If both standard output and standard error of the executed processes are connected to the journal via a |
2755 | stream socket, this environment variable will contain information about the standard error stream, as that's | |
2756 | usually the preferred destination for log data. (Note that typically the same stream is used for both standard | |
2757 | output and standard error, hence very likely the environment variable contains device and inode information | |
2758 | matching both stream file descriptors.)</para> | |
2759 | ||
7bce046b LP |
2760 | <para>This environment variable is primarily useful to allow services to optionally upgrade their used log |
2761 | protocol to the native journal protocol (using | |
2762 | <citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry> and other | |
2763 | functions) if their standard output or standard error output is connected to the journal anyway, thus enabling | |
2764 | delivery of structured metadata along with logged messages.</para></listitem> | |
2765 | </varlistentry> | |
136dc4c4 LP |
2766 | |
2767 | <varlistentry> | |
2768 | <term><varname>$SERVICE_RESULT</varname></term> | |
2769 | ||
2770 | <listitem><para>Only defined for the service unit type, this environment variable is passed to all | |
2771 | <varname>ExecStop=</varname> and <varname>ExecStopPost=</varname> processes, and encodes the service | |
38a7c3c0 LP |
2772 | "result". Currently, the following values are defined:</para> |
2773 | ||
2774 | <table> | |
2775 | <title>Defined <varname>$SERVICE_RESULT</varname> values</title> | |
2776 | <tgroup cols='2'> | |
2777 | <colspec colname='result'/> | |
2778 | <colspec colname='meaning'/> | |
2779 | <thead> | |
2780 | <row> | |
2781 | <entry>Value</entry> | |
2782 | <entry>Meaning</entry> | |
2783 | </row> | |
2784 | </thead> | |
2785 | ||
2786 | <tbody> | |
2787 | <row> | |
2788 | <entry><literal>success</literal></entry> | |
e124ccdf | 2789 | <entry>The service ran successfully and exited cleanly.</entry> |
38a7c3c0 LP |
2790 | </row> |
2791 | <row> | |
2792 | <entry><literal>protocol</literal></entry> | |
e124ccdf | 2793 | <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 |
2794 | </row> |
2795 | <row> | |
2796 | <entry><literal>timeout</literal></entry> | |
e124ccdf | 2797 | <entry>One of the steps timed out.</entry> |
38a7c3c0 LP |
2798 | </row> |
2799 | <row> | |
2800 | <entry><literal>exit-code</literal></entry> | |
e124ccdf | 2801 | <entry>Service process exited with a non-zero exit code; see <varname>$EXIT_CODE</varname> below for the actual exit code returned.</entry> |
38a7c3c0 LP |
2802 | </row> |
2803 | <row> | |
2804 | <entry><literal>signal</literal></entry> | |
e124ccdf | 2805 | <entry>A service process was terminated abnormally by a signal, without dumping core. See <varname>$EXIT_CODE</varname> below for the actual signal causing the termination.</entry> |
38a7c3c0 LP |
2806 | </row> |
2807 | <row> | |
2808 | <entry><literal>core-dump</literal></entry> | |
e124ccdf | 2809 | <entry>A service process terminated abnormally with a signal and dumped core. See <varname>$EXIT_CODE</varname> below for the signal causing the termination.</entry> |
38a7c3c0 LP |
2810 | </row> |
2811 | <row> | |
2812 | <entry><literal>watchdog</literal></entry> | |
e124ccdf | 2813 | <entry>Watchdog keep-alive ping was enabled for the service, but the deadline was missed.</entry> |
38a7c3c0 LP |
2814 | </row> |
2815 | <row> | |
2816 | <entry><literal>start-limit-hit</literal></entry> | |
e124ccdf | 2817 | <entry>A start limit was defined for the unit and it was hit, causing the unit to fail to start. See <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s <varname>StartLimitIntervalSec=</varname> and <varname>StartLimitBurst=</varname> for details.</entry> |
38a7c3c0 LP |
2818 | </row> |
2819 | <row> | |
2820 | <entry><literal>resources</literal></entry> | |
2821 | <entry>A catch-all condition in case a system operation failed.</entry> | |
2822 | </row> | |
2823 | </tbody> | |
2824 | </tgroup> | |
2825 | </table> | |
136dc4c4 LP |
2826 | |
2827 | <para>This environment variable is useful to monitor failure or successful termination of a service. Even | |
2828 | though this variable is available in both <varname>ExecStop=</varname> and <varname>ExecStopPost=</varname>, it | |
2829 | is usually a better choice to place monitoring tools in the latter, as the former is only invoked for services | |
2830 | that managed to start up correctly, and the latter covers both services that failed during their start-up and | |
2831 | those which failed during their runtime.</para></listitem> | |
2832 | </varlistentry> | |
2833 | ||
2834 | <varlistentry> | |
2835 | <term><varname>$EXIT_CODE</varname></term> | |
2836 | <term><varname>$EXIT_STATUS</varname></term> | |
2837 | ||
2838 | <listitem><para>Only defined for the service unit type, these environment variables are passed to all | |
2839 | <varname>ExecStop=</varname>, <varname>ExecStopPost=</varname> processes and contain exit status/code | |
2840 | information of the main process of the service. For the precise definition of the exit code and status, see | |
2841 | <citerefentry><refentrytitle>wait</refentrytitle><manvolnum>2</manvolnum></citerefentry>. <varname>$EXIT_CODE</varname> | |
2842 | is one of <literal>exited</literal>, <literal>killed</literal>, | |
2843 | <literal>dumped</literal>. <varname>$EXIT_STATUS</varname> contains the numeric exit code formatted as string | |
2844 | if <varname>$EXIT_CODE</varname> is <literal>exited</literal>, and the signal name in all other cases. Note | |
2845 | that these environment variables are only set if the service manager succeeded to start and identify the main | |
e64e1bfd ZJS |
2846 | process of the service.</para> |
2847 | ||
2848 | <table> | |
2849 | <title>Summary of possible service result variable values</title> | |
2850 | <tgroup cols='3'> | |
2851 | <colspec colname='result' /> | |
e64e1bfd | 2852 | <colspec colname='code' /> |
a4e26faf | 2853 | <colspec colname='status' /> |
e64e1bfd ZJS |
2854 | <thead> |
2855 | <row> | |
2856 | <entry><varname>$SERVICE_RESULT</varname></entry> | |
e64e1bfd | 2857 | <entry><varname>$EXIT_CODE</varname></entry> |
a4e26faf | 2858 | <entry><varname>$EXIT_STATUS</varname></entry> |
e64e1bfd ZJS |
2859 | </row> |
2860 | </thead> | |
2861 | ||
2862 | <tbody> | |
38a7c3c0 | 2863 | <row> |
b1222962 C |
2864 | <entry morerows="1" valign="top"><literal>success</literal></entry> |
2865 | <entry valign="top"><literal>killed</literal></entry> | |
2866 | <entry><literal>HUP</literal>, <literal>INT</literal>, <literal>TERM</literal>, <literal>PIPE</literal></entry> | |
2867 | </row> | |
2868 | <row> | |
38a7c3c0 LP |
2869 | <entry valign="top"><literal>exited</literal></entry> |
2870 | <entry><literal>0</literal></entry> | |
2871 | </row> | |
a4e26faf JW |
2872 | <row> |
2873 | <entry morerows="1" valign="top"><literal>protocol</literal></entry> | |
2874 | <entry valign="top">not set</entry> | |
2875 | <entry>not set</entry> | |
2876 | </row> | |
2877 | <row> | |
2878 | <entry><literal>exited</literal></entry> | |
2879 | <entry><literal>0</literal></entry> | |
2880 | </row> | |
29df65f9 ZJS |
2881 | <row> |
2882 | <entry morerows="1" valign="top"><literal>timeout</literal></entry> | |
2883 | <entry valign="top"><literal>killed</literal></entry> | |
6757c06a | 2884 | <entry><literal>TERM</literal>, <literal>KILL</literal></entry> |
29df65f9 | 2885 | </row> |
29df65f9 ZJS |
2886 | <row> |
2887 | <entry valign="top"><literal>exited</literal></entry> | |
6757c06a LP |
2888 | <entry><literal>0</literal>, <literal>1</literal>, <literal>2</literal>, <literal |
2889 | >3</literal>, …, <literal>255</literal></entry> | |
29df65f9 | 2890 | </row> |
e64e1bfd ZJS |
2891 | <row> |
2892 | <entry valign="top"><literal>exit-code</literal></entry> | |
2893 | <entry valign="top"><literal>exited</literal></entry> | |
38a7c3c0 | 2894 | <entry><literal>1</literal>, <literal>2</literal>, <literal |
6757c06a | 2895 | >3</literal>, …, <literal>255</literal></entry> |
e64e1bfd | 2896 | </row> |
e64e1bfd ZJS |
2897 | <row> |
2898 | <entry valign="top"><literal>signal</literal></entry> | |
2899 | <entry valign="top"><literal>killed</literal></entry> | |
6757c06a | 2900 | <entry><literal>HUP</literal>, <literal>INT</literal>, <literal>KILL</literal>, …</entry> |
e64e1bfd | 2901 | </row> |
e64e1bfd ZJS |
2902 | <row> |
2903 | <entry valign="top"><literal>core-dump</literal></entry> | |
2904 | <entry valign="top"><literal>dumped</literal></entry> | |
6757c06a | 2905 | <entry><literal>ABRT</literal>, <literal>SEGV</literal>, <literal>QUIT</literal>, …</entry> |
e64e1bfd | 2906 | </row> |
e64e1bfd ZJS |
2907 | <row> |
2908 | <entry morerows="2" valign="top"><literal>watchdog</literal></entry> | |
2909 | <entry><literal>dumped</literal></entry> | |
2910 | <entry><literal>ABRT</literal></entry> | |
2911 | </row> | |
2912 | <row> | |
2913 | <entry><literal>killed</literal></entry> | |
6757c06a | 2914 | <entry><literal>TERM</literal>, <literal>KILL</literal></entry> |
e64e1bfd ZJS |
2915 | </row> |
2916 | <row> | |
2917 | <entry><literal>exited</literal></entry> | |
6757c06a LP |
2918 | <entry><literal>0</literal>, <literal>1</literal>, <literal>2</literal>, <literal |
2919 | >3</literal>, …, <literal>255</literal></entry> | |
e64e1bfd | 2920 | </row> |
b1222962 C |
2921 | <row> |
2922 | <entry valign="top"><literal>exec-condition</literal></entry> | |
2923 | <entry><literal>exited</literal></entry> | |
2924 | <entry><literal>1</literal>, <literal>2</literal>, <literal>3</literal>, <literal | |
2925 | >4</literal>, …, <literal>254</literal></entry> | |
2926 | </row> | |
2927 | <row> | |
2928 | <entry valign="top"><literal>oom-kill</literal></entry> | |
2929 | <entry valign="top"><literal>killed</literal></entry> | |
2930 | <entry><literal>TERM</literal>, <literal>KILL</literal></entry> | |
2931 | </row> | |
38a7c3c0 LP |
2932 | <row> |
2933 | <entry><literal>start-limit-hit</literal></entry> | |
2934 | <entry>not set</entry> | |
2935 | <entry>not set</entry> | |
2936 | </row> | |
e64e1bfd ZJS |
2937 | <row> |
2938 | <entry><literal>resources</literal></entry> | |
2939 | <entry>any of the above</entry> | |
2940 | <entry>any of the above</entry> | |
2941 | </row> | |
29df65f9 | 2942 | <row> |
38a7c3c0 | 2943 | <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 | 2944 | </row> |
e64e1bfd ZJS |
2945 | </tbody> |
2946 | </tgroup> | |
2947 | </table> | |
2948 | ||
2949 | </listitem> | |
2950 | </varlistentry> | |
dcf3c3c3 LP |
2951 | |
2952 | <varlistentry> | |
2953 | <term><varname>$PIDFILE</varname></term> | |
2954 | ||
2955 | <listitem><para>The path to the configured PID file, in case the process is forked off on behalf of a | |
2956 | service that uses the <varname>PIDFile=</varname> setting, see | |
2957 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
2958 | for details. Service code may use this environment variable to automatically generate a PID file at | |
2959 | the location configured in the unit file. This field is set to an absolute path in the file | |
2960 | system.</para></listitem> | |
2961 | </varlistentry> | |
2962 | ||
798d3a52 | 2963 | </variablelist> |
46b07329 LP |
2964 | |
2965 | <para>For system services, when <varname>PAMName=</varname> is enabled and <command>pam_systemd</command> is part | |
2966 | of the selected PAM stack, additional environment variables defined by systemd may be set for | |
2967 | services. Specifically, these are <varname>$XDG_SEAT</varname>, <varname>$XDG_VTNR</varname>, see | |
2968 | <citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry> for details.</para> | |
798d3a52 ZJS |
2969 | </refsect1> |
2970 | ||
91a8f867 JS |
2971 | <refsect1> |
2972 | <title>Process exit codes</title> | |
2973 | ||
2974 | <para>When invoking a unit process the service manager possibly fails to apply the execution parameters configured | |
2975 | with the settings above. In that case the already created service process will exit with a non-zero exit code | |
2976 | before the configured command line is executed. (Or in other words, the child process possibly exits with these | |
2977 | error codes, after having been created by the <citerefentry | |
2978 | project='man-pages'><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call, but | |
2979 | before the matching <citerefentry | |
2980 | project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call is | |
2981 | called.) Specifically, exit codes defined by the C library, by the LSB specification and by the systemd service | |
2982 | manager itself are used.</para> | |
2983 | ||
2984 | <para>The following basic service exit codes are defined by the C library.</para> | |
2985 | ||
2986 | <table> | |
2987 | <title>Basic C library exit codes</title> | |
2988 | <tgroup cols='3'> | |
2989 | <thead> | |
2990 | <row> | |
2991 | <entry>Exit Code</entry> | |
2992 | <entry>Symbolic Name</entry> | |
2993 | <entry>Description</entry> | |
2994 | </row> | |
2995 | </thead> | |
2996 | <tbody> | |
2997 | <row> | |
2998 | <entry>0</entry> | |
2999 | <entry><constant>EXIT_SUCCESS</constant></entry> | |
3000 | <entry>Generic success code.</entry> | |
3001 | </row> | |
3002 | <row> | |
3003 | <entry>1</entry> | |
3004 | <entry><constant>EXIT_FAILURE</constant></entry> | |
3005 | <entry>Generic failure or unspecified error.</entry> | |
3006 | </row> | |
3007 | </tbody> | |
3008 | </tgroup> | |
3009 | </table> | |
3010 | ||
3011 | <para>The following service exit codes are defined by the <ulink | |
29a3d5ca | 3012 | url="https://refspecs.linuxbase.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/iniscrptact.html">LSB specification</ulink>. |
91a8f867 JS |
3013 | </para> |
3014 | ||
3015 | <table> | |
3016 | <title>LSB service exit codes</title> | |
3017 | <tgroup cols='3'> | |
3018 | <thead> | |
3019 | <row> | |
3020 | <entry>Exit Code</entry> | |
3021 | <entry>Symbolic Name</entry> | |
3022 | <entry>Description</entry> | |
3023 | </row> | |
3024 | </thead> | |
3025 | <tbody> | |
3026 | <row> | |
3027 | <entry>2</entry> | |
3028 | <entry><constant>EXIT_INVALIDARGUMENT</constant></entry> | |
3029 | <entry>Invalid or excess arguments.</entry> | |
3030 | </row> | |
3031 | <row> | |
3032 | <entry>3</entry> | |
3033 | <entry><constant>EXIT_NOTIMPLEMENTED</constant></entry> | |
3034 | <entry>Unimplemented feature.</entry> | |
3035 | </row> | |
3036 | <row> | |
3037 | <entry>4</entry> | |
3038 | <entry><constant>EXIT_NOPERMISSION</constant></entry> | |
3039 | <entry>The user has insufficient privileges.</entry> | |
3040 | </row> | |
3041 | <row> | |
3042 | <entry>5</entry> | |
3043 | <entry><constant>EXIT_NOTINSTALLED</constant></entry> | |
3044 | <entry>The program is not installed.</entry> | |
3045 | </row> | |
3046 | <row> | |
3047 | <entry>6</entry> | |
3048 | <entry><constant>EXIT_NOTCONFIGURED</constant></entry> | |
3049 | <entry>The program is not configured.</entry> | |
3050 | </row> | |
3051 | <row> | |
3052 | <entry>7</entry> | |
3053 | <entry><constant>EXIT_NOTRUNNING</constant></entry> | |
3054 | <entry>The program is not running.</entry> | |
3055 | </row> | |
3056 | </tbody> | |
3057 | </tgroup> | |
3058 | </table> | |
3059 | ||
3060 | <para> | |
3061 | The LSB specification suggests that error codes 200 and above are reserved for implementations. Some of them are | |
3062 | used by the service manager to indicate problems during process invocation: | |
3063 | </para> | |
3064 | <table> | |
3065 | <title>systemd-specific exit codes</title> | |
3066 | <tgroup cols='3'> | |
3067 | <thead> | |
3068 | <row> | |
3069 | <entry>Exit Code</entry> | |
3070 | <entry>Symbolic Name</entry> | |
3071 | <entry>Description</entry> | |
3072 | </row> | |
3073 | </thead> | |
3074 | <tbody> | |
3075 | <row> | |
3076 | <entry>200</entry> | |
3077 | <entry><constant>EXIT_CHDIR</constant></entry> | |
3078 | <entry>Changing to the requested working directory failed. See <varname>WorkingDirectory=</varname> above.</entry> | |
3079 | </row> | |
3080 | <row> | |
3081 | <entry>201</entry> | |
3082 | <entry><constant>EXIT_NICE</constant></entry> | |
3083 | <entry>Failed to set up process scheduling priority (nice level). See <varname>Nice=</varname> above.</entry> | |
3084 | </row> | |
3085 | <row> | |
3086 | <entry>202</entry> | |
3087 | <entry><constant>EXIT_FDS</constant></entry> | |
3088 | <entry>Failed to close unwanted file descriptors, or to adjust passed file descriptors.</entry> | |
3089 | </row> | |
3090 | <row> | |
3091 | <entry>203</entry> | |
3092 | <entry><constant>EXIT_EXEC</constant></entry> | |
3093 | <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> | |
3094 | </row> | |
3095 | <row> | |
3096 | <entry>204</entry> | |
3097 | <entry><constant>EXIT_MEMORY</constant></entry> | |
3098 | <entry>Failed to perform an action due to memory shortage.</entry> | |
3099 | </row> | |
3100 | <row> | |
3101 | <entry>205</entry> | |
3102 | <entry><constant>EXIT_LIMITS</constant></entry> | |
dcfaecc7 | 3103 | <entry>Failed to adjust resource limits. See <varname>LimitCPU=</varname> and related settings above.</entry> |
91a8f867 JS |
3104 | </row> |
3105 | <row> | |
3106 | <entry>206</entry> | |
3107 | <entry><constant>EXIT_OOM_ADJUST</constant></entry> | |
3108 | <entry>Failed to adjust the OOM setting. See <varname>OOMScoreAdjust=</varname> above.</entry> | |
3109 | </row> | |
3110 | <row> | |
3111 | <entry>207</entry> | |
3112 | <entry><constant>EXIT_SIGNAL_MASK</constant></entry> | |
3113 | <entry>Failed to set process signal mask.</entry> | |
3114 | </row> | |
3115 | <row> | |
3116 | <entry>208</entry> | |
3117 | <entry><constant>EXIT_STDIN</constant></entry> | |
3118 | <entry>Failed to set up standard input. See <varname>StandardInput=</varname> above.</entry> | |
3119 | </row> | |
3120 | <row> | |
3121 | <entry>209</entry> | |
3122 | <entry><constant>EXIT_STDOUT</constant></entry> | |
3123 | <entry>Failed to set up standard output. See <varname>StandardOutput=</varname> above.</entry> | |
3124 | </row> | |
3125 | <row> | |
3126 | <entry>210</entry> | |
3127 | <entry><constant>EXIT_CHROOT</constant></entry> | |
3128 | <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> | |
3129 | </row> | |
3130 | <row> | |
3131 | <entry>211</entry> | |
3132 | <entry><constant>EXIT_IOPRIO</constant></entry> | |
3133 | <entry>Failed to set up IO scheduling priority. See <varname>IOSchedulingClass=</varname>/<varname>IOSchedulingPriority=</varname> above.</entry> | |
3134 | </row> | |
3135 | <row> | |
3136 | <entry>212</entry> | |
3137 | <entry><constant>EXIT_TIMERSLACK</constant></entry> | |
3138 | <entry>Failed to set up timer slack. See <varname>TimerSlackNSec=</varname> above.</entry> | |
3139 | </row> | |
3140 | <row> | |
3141 | <entry>213</entry> | |
3142 | <entry><constant>EXIT_SECUREBITS</constant></entry> | |
3143 | <entry>Failed to set process secure bits. See <varname>SecureBits=</varname> above.</entry> | |
3144 | </row> | |
3145 | <row> | |
3146 | <entry>214</entry> | |
3147 | <entry><constant>EXIT_SETSCHEDULER</constant></entry> | |
3148 | <entry>Failed to set up CPU scheduling. See <varname>CPUSchedulingPolicy=</varname>/<varname>CPUSchedulingPriority=</varname> above.</entry> | |
3149 | </row> | |
3150 | <row> | |
3151 | <entry>215</entry> | |
3152 | <entry><constant>EXIT_CPUAFFINITY</constant></entry> | |
3153 | <entry>Failed to set up CPU affinity. See <varname>CPUAffinity=</varname> above.</entry> | |
3154 | </row> | |
3155 | <row> | |
3156 | <entry>216</entry> | |
3157 | <entry><constant>EXIT_GROUP</constant></entry> | |
3158 | <entry>Failed to determine or change group credentials. See <varname>Group=</varname>/<varname>SupplementaryGroups=</varname> above.</entry> | |
3159 | </row> | |
3160 | <row> | |
3161 | <entry>217</entry> | |
3162 | <entry><constant>EXIT_USER</constant></entry> | |
3163 | <entry>Failed to determine or change user credentials, or to set up user namespacing. See <varname>User=</varname>/<varname>PrivateUsers=</varname> above.</entry> | |
3164 | </row> | |
3165 | <row> | |
3166 | <entry>218</entry> | |
3167 | <entry><constant>EXIT_CAPABILITIES</constant></entry> | |
3168 | <entry>Failed to drop capabilities, or apply ambient capabilities. See <varname>CapabilityBoundingSet=</varname>/<varname>AmbientCapabilities=</varname> above.</entry> | |
3169 | </row> | |
3170 | <row> | |
3171 | <entry>219</entry> | |
3172 | <entry><constant>EXIT_CGROUP</constant></entry> | |
3173 | <entry>Setting up the service control group failed.</entry> | |
3174 | </row> | |
3175 | <row> | |
3176 | <entry>220</entry> | |
3177 | <entry><constant>EXIT_SETSID</constant></entry> | |
3178 | <entry>Failed to create new process session.</entry> | |
3179 | </row> | |
3180 | <row> | |
3181 | <entry>221</entry> | |
3182 | <entry><constant>EXIT_CONFIRM</constant></entry> | |
3183 | <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> | |
3184 | </row> | |
3185 | <row> | |
3186 | <entry>222</entry> | |
3187 | <entry><constant>EXIT_STDERR</constant></entry> | |
3188 | <entry>Failed to set up standard error output. See <varname>StandardError=</varname> above.</entry> | |
3189 | </row> | |
3190 | <row> | |
3191 | <entry>224</entry> | |
3192 | <entry><constant>EXIT_PAM</constant></entry> | |
3193 | <entry>Failed to set up PAM session. See <varname>PAMName=</varname> above.</entry> | |
3194 | </row> | |
3195 | <row> | |
3196 | <entry>225</entry> | |
3197 | <entry><constant>EXIT_NETWORK</constant></entry> | |
3198 | <entry>Failed to set up network namespacing. See <varname>PrivateNetwork=</varname> above.</entry> | |
3199 | </row> | |
3200 | <row> | |
3201 | <entry>226</entry> | |
3202 | <entry><constant>EXIT_NAMESPACE</constant></entry> | |
3203 | <entry>Failed to set up mount namespacing. See <varname>ReadOnlyPaths=</varname> and related settings above.</entry> | |
3204 | </row> | |
3205 | <row> | |
3206 | <entry>227</entry> | |
3207 | <entry><constant>EXIT_NO_NEW_PRIVILEGES</constant></entry> | |
dcfaecc7 | 3208 | <entry>Failed to disable new privileges. See <varname>NoNewPrivileges=yes</varname> above.</entry> |
91a8f867 JS |
3209 | </row> |
3210 | <row> | |
3211 | <entry>228</entry> | |
3212 | <entry><constant>EXIT_SECCOMP</constant></entry> | |
3213 | <entry>Failed to apply system call filters. See <varname>SystemCallFilter=</varname> and related settings above.</entry> | |
3214 | </row> | |
3215 | <row> | |
3216 | <entry>229</entry> | |
3217 | <entry><constant>EXIT_SELINUX_CONTEXT</constant></entry> | |
3218 | <entry>Determining or changing SELinux context failed. See <varname>SELinuxContext=</varname> above.</entry> | |
3219 | </row> | |
3220 | <row> | |
3221 | <entry>230</entry> | |
3222 | <entry><constant>EXIT_PERSONALITY</constant></entry> | |
dcfaecc7 | 3223 | <entry>Failed to set up an execution domain (personality). See <varname>Personality=</varname> above.</entry> |
91a8f867 JS |
3224 | </row> |
3225 | <row> | |
3226 | <entry>231</entry> | |
3227 | <entry><constant>EXIT_APPARMOR_PROFILE</constant></entry> | |
3228 | <entry>Failed to prepare changing AppArmor profile. See <varname>AppArmorProfile=</varname> above.</entry> | |
3229 | </row> | |
3230 | <row> | |
3231 | <entry>232</entry> | |
3232 | <entry><constant>EXIT_ADDRESS_FAMILIES</constant></entry> | |
3233 | <entry>Failed to restrict address families. See <varname>RestrictAddressFamilies=</varname> above.</entry> | |
3234 | </row> | |
3235 | <row> | |
3236 | <entry>233</entry> | |
3237 | <entry><constant>EXIT_RUNTIME_DIRECTORY</constant></entry> | |
3238 | <entry>Setting up runtime directory failed. See <varname>RuntimeDirectory=</varname> and related settings above.</entry> | |
3239 | </row> | |
3240 | <row> | |
3241 | <entry>235</entry> | |
3242 | <entry><constant>EXIT_CHOWN</constant></entry> | |
3243 | <entry>Failed to adjust socket ownership. Used for socket units only.</entry> | |
3244 | </row> | |
3245 | <row> | |
3246 | <entry>236</entry> | |
3247 | <entry><constant>EXIT_SMACK_PROCESS_LABEL</constant></entry> | |
3248 | <entry>Failed to set SMACK label. See <varname>SmackProcessLabel=</varname> above.</entry> | |
3249 | </row> | |
3250 | <row> | |
3251 | <entry>237</entry> | |
3252 | <entry><constant>EXIT_KEYRING</constant></entry> | |
3253 | <entry>Failed to set up kernel keyring.</entry> | |
3254 | </row> | |
3255 | <row> | |
3256 | <entry>238</entry> | |
3257 | <entry><constant>EXIT_STATE_DIRECTORY</constant></entry> | |
dcfaecc7 | 3258 | <entry>Failed to set up unit's state directory. See <varname>StateDirectory=</varname> above.</entry> |
91a8f867 JS |
3259 | </row> |
3260 | <row> | |
3261 | <entry>239</entry> | |
3262 | <entry><constant>EXIT_CACHE_DIRECTORY</constant></entry> | |
dcfaecc7 | 3263 | <entry>Failed to set up unit's cache directory. See <varname>CacheDirectory=</varname> above.</entry> |
91a8f867 JS |
3264 | </row> |
3265 | <row> | |
3266 | <entry>240</entry> | |
3267 | <entry><constant>EXIT_LOGS_DIRECTORY</constant></entry> | |
dcfaecc7 | 3268 | <entry>Failed to set up unit's logging directory. See <varname>LogsDirectory=</varname> above.</entry> |
91a8f867 JS |
3269 | </row> |
3270 | <row> | |
3271 | <entry>241</entry> | |
3272 | <entry><constant>EXIT_CONFIGURATION_DIRECTORY</constant></entry> | |
dcfaecc7 | 3273 | <entry>Failed to set up unit's configuration directory. See <varname>ConfigurationDirectory=</varname> above.</entry> |
91a8f867 | 3274 | </row> |
b070c7c0 MS |
3275 | <row> |
3276 | <entry>242</entry> | |
3277 | <entry><constant>EXIT_NUMA_POLICY</constant></entry> | |
e9dd6984 | 3278 | <entry>Failed to set up unit's NUMA memory policy. See <varname>NUMAPolicy=</varname> and <varname>NUMAMask=</varname> above.</entry> |
b070c7c0 MS |
3279 | </row> |
3280 | ||
91a8f867 JS |
3281 | </tbody> |
3282 | </tgroup> | |
3283 | </table> | |
3e0bff7d LP |
3284 | |
3285 | <para>Finally, the BSD operating systems define a set of exit codes, typically defined on Linux systems too:</para> | |
3286 | ||
3287 | <table> | |
3288 | <title>BSD exit codes</title> | |
3289 | <tgroup cols='3'> | |
3290 | <thead> | |
3291 | <row> | |
3292 | <entry>Exit Code</entry> | |
3293 | <entry>Symbolic Name</entry> | |
3294 | <entry>Description</entry> | |
3295 | </row> | |
3296 | </thead> | |
3297 | <tbody> | |
3298 | <row> | |
3299 | <entry>64</entry> | |
3300 | <entry><constant>EX_USAGE</constant></entry> | |
3301 | <entry>Command line usage error</entry> | |
3302 | </row> | |
3303 | <row> | |
3304 | <entry>65</entry> | |
3305 | <entry><constant>EX_DATAERR</constant></entry> | |
3306 | <entry>Data format error</entry> | |
3307 | </row> | |
3308 | <row> | |
3309 | <entry>66</entry> | |
3310 | <entry><constant>EX_NOINPUT</constant></entry> | |
3311 | <entry>Cannot open input</entry> | |
3312 | </row> | |
3313 | <row> | |
3314 | <entry>67</entry> | |
3315 | <entry><constant>EX_NOUSER</constant></entry> | |
3316 | <entry>Addressee unknown</entry> | |
3317 | </row> | |
3318 | <row> | |
3319 | <entry>68</entry> | |
3320 | <entry><constant>EX_NOHOST</constant></entry> | |
3321 | <entry>Host name unknown</entry> | |
3322 | </row> | |
3323 | <row> | |
3324 | <entry>69</entry> | |
3325 | <entry><constant>EX_UNAVAILABLE</constant></entry> | |
3326 | <entry>Service unavailable</entry> | |
3327 | </row> | |
3328 | <row> | |
3329 | <entry>70</entry> | |
3330 | <entry><constant>EX_SOFTWARE</constant></entry> | |
3331 | <entry>internal software error</entry> | |
3332 | </row> | |
3333 | <row> | |
3334 | <entry>71</entry> | |
3335 | <entry><constant>EX_OSERR</constant></entry> | |
3336 | <entry>System error (e.g., can't fork)</entry> | |
3337 | </row> | |
3338 | <row> | |
3339 | <entry>72</entry> | |
3340 | <entry><constant>EX_OSFILE</constant></entry> | |
3341 | <entry>Critical OS file missing</entry> | |
3342 | </row> | |
3343 | <row> | |
3344 | <entry>73</entry> | |
3345 | <entry><constant>EX_CANTCREAT</constant></entry> | |
3346 | <entry>Can't create (user) output file</entry> | |
3347 | </row> | |
3348 | <row> | |
3349 | <entry>74</entry> | |
3350 | <entry><constant>EX_IOERR</constant></entry> | |
3351 | <entry>Input/output error</entry> | |
3352 | </row> | |
3353 | <row> | |
3354 | <entry>75</entry> | |
3355 | <entry><constant>EX_TEMPFAIL</constant></entry> | |
3356 | <entry>Temporary failure; user is invited to retry</entry> | |
3357 | </row> | |
3358 | <row> | |
3359 | <entry>76</entry> | |
3360 | <entry><constant>EX_PROTOCOL</constant></entry> | |
3361 | <entry>Remote error in protocol</entry> | |
3362 | </row> | |
3363 | <row> | |
3364 | <entry>77</entry> | |
3365 | <entry><constant>EX_NOPERM</constant></entry> | |
3366 | <entry>Permission denied</entry> | |
3367 | </row> | |
3368 | <row> | |
3369 | <entry>78</entry> | |
3370 | <entry><constant>EX_CONFIG</constant></entry> | |
3371 | <entry>Configuration error</entry> | |
3372 | </row> | |
3373 | </tbody> | |
3374 | </tgroup> | |
3375 | </table> | |
91a8f867 JS |
3376 | </refsect1> |
3377 | ||
798d3a52 ZJS |
3378 | <refsect1> |
3379 | <title>See Also</title> | |
3380 | <para> | |
3381 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
3382 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
869feb33 | 3383 | <citerefentry><refentrytitle>systemd-analyze</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
68d838f7 | 3384 | <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
d1698b82 | 3385 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
798d3a52 ZJS |
3386 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
3387 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
3388 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
3389 | <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
3390 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
3391 | <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
3392 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
a4c18002 | 3393 | <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
798d3a52 ZJS |
3394 | <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
3395 | <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
3396 | <citerefentry project='man-pages'><refentrytitle>exec</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
3397 | </para> | |
3398 | </refsect1> | |
dd1eb43b LP |
3399 | |
3400 | </refentry> |