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b36b082c | 1 | <?xml version='1.0'?> <!--*-nxml-*--> |
b36b082c | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
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4 | |
5 | <!-- | |
572eb058 | 6 | SPDX-License-Identifier: LGPL-2.1+ |
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7 | --> |
8 | ||
9 | <refentry id="systemd.path"> | |
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10 | <refentryinfo> |
11 | <title>systemd.path</title> | |
12 | <productname>systemd</productname> | |
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13 | </refentryinfo> |
14 | ||
15 | <refmeta> | |
16 | <refentrytitle>systemd.path</refentrytitle> | |
17 | <manvolnum>5</manvolnum> | |
18 | </refmeta> | |
19 | ||
20 | <refnamediv> | |
21 | <refname>systemd.path</refname> | |
22 | <refpurpose>Path unit configuration</refpurpose> | |
23 | </refnamediv> | |
24 | ||
25 | <refsynopsisdiv> | |
26 | <para><filename><replaceable>path</replaceable>.path</filename></para> | |
27 | </refsynopsisdiv> | |
28 | ||
29 | <refsect1> | |
30 | <title>Description</title> | |
31 | ||
32 | <para>A unit configuration file whose name ends in | |
33 | <literal>.path</literal> encodes information about a path | |
34 | monitored by systemd, for path-based activation.</para> | |
35 | ||
36 | <para>This man page lists the configuration options specific to | |
37 | this unit type. See | |
38 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
39 | for the common options of all unit configuration files. The common | |
40 | configuration items are configured in the generic [Unit] and | |
41 | [Install] sections. The path specific configuration options are | |
42 | configured in the [Path] section.</para> | |
43 | ||
44 | <para>For each path file, a matching unit file must exist, | |
45 | describing the unit to activate when the path changes. By default, | |
46 | a service by the same name as the path (except for the suffix) is | |
47 | activated. Example: a path file <filename>foo.path</filename> | |
48 | activates a matching service <filename>foo.service</filename>. The | |
49 | unit to activate may be controlled by <varname>Unit=</varname> | |
50 | (see below).</para> | |
51 | ||
52 | <para>Internally, path units use the | |
3ba3a79d | 53 | <citerefentry project='man-pages'><refentrytitle>inotify</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
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54 | API to monitor file systems. Due to that, it suffers by the same |
55 | limitations as inotify, and for example cannot be used to monitor | |
56 | files or directories changed by other machines on remote NFS file | |
57 | systems.</para> | |
c129bd5d | 58 | </refsect1> |
798d3a52 | 59 | |
c129bd5d | 60 | <refsect1> |
aed5cb03 | 61 | <title>Automatic Dependencies</title> |
45f09f93 | 62 | |
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63 | <refsect2> |
64 | <title>Implicit Dependencies</title> | |
45f09f93 | 65 | |
aed5cb03 | 66 | <para>The following dependencies are implicitly added:</para> |
45f09f93 | 67 | |
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68 | <itemizedlist> |
69 | <listitem><para>If a path unit is beneath another mount unit in the file | |
70 | system hierarchy, both a requirement and an ordering dependency | |
71 | between both units are created automatically.</para></listitem> | |
45f09f93 | 72 | |
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73 | <listitem><para>An implicit <varname>Before=</varname> dependency is added |
74 | between a path unit and the unit it is supposed to activate.</para></listitem> | |
75 | </itemizedlist> | |
76 | </refsect2> | |
77 | ||
78 | <refsect2> | |
79 | <title>Default Dependencies</title> | |
45f09f93 | 80 | |
aed5cb03 | 81 | <para>The following dependencies are added unless <varname>DefaultDependencies=no</varname> is set:</para> |
45f09f93 | 82 | |
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83 | <itemizedlist> |
84 | <listitem><para>Path units will automatically have dependencies of type <varname>Before=</varname> on | |
85 | <filename>paths.target</filename>, | |
86 | dependencies of type <varname>After=</varname> and <varname>Requires=</varname> on | |
87 | <filename>sysinit.target</filename>, and have dependencies of type <varname>Conflicts=</varname> and | |
88 | <varname>Before=</varname> on <filename>shutdown.target</filename>. These ensure that path units are terminated | |
89 | cleanly prior to system shutdown. Only path units involved with early boot or late system shutdown should | |
90 | disable <varname>DefaultDependencies=</varname> option.</para></listitem> | |
91 | </itemizedlist> | |
45f09f93 | 92 | |
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93 | <para></para> |
94 | </refsect2> | |
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95 | </refsect1> |
96 | ||
97 | <refsect1> | |
98 | <title>Options</title> | |
99 | ||
100 | <para>Path files must include a [Path] section, which carries | |
101 | information about the path(s) it monitors. The options specific to | |
102 | the [Path] section of path units are the following:</para> | |
103 | ||
104 | <variablelist class='unit-directives'> | |
105 | <varlistentry> | |
106 | <term><varname>PathExists=</varname></term> | |
107 | <term><varname>PathExistsGlob=</varname></term> | |
108 | <term><varname>PathChanged=</varname></term> | |
109 | <term><varname>PathModified=</varname></term> | |
110 | <term><varname>DirectoryNotEmpty=</varname></term> | |
111 | ||
112 | <listitem><para>Defines paths to monitor for certain changes: | |
113 | <varname>PathExists=</varname> may be used to watch the mere | |
114 | existence of a file or directory. If the file specified | |
115 | exists, the configured unit is activated. | |
116 | <varname>PathExistsGlob=</varname> works similar, but checks | |
117 | for the existence of at least one file matching the globbing | |
118 | pattern specified. <varname>PathChanged=</varname> may be used | |
119 | to watch a file or directory and activate the configured unit | |
120 | whenever it changes. It is not activated on every write to the | |
121 | watched file but it is activated if the file which was open | |
122 | for writing gets closed. <varname>PathModified=</varname> is | |
123 | similar, but additionally it is activated also on simple | |
124 | writes to the watched file. | |
125 | <varname>DirectoryNotEmpty=</varname> may be used to watch a | |
126 | directory and activate the configured unit whenever it | |
127 | contains at least one file.</para> | |
128 | ||
129 | <para>The arguments of these directives must be absolute file | |
130 | system paths.</para> | |
131 | ||
132 | <para>Multiple directives may be combined, of the same and of | |
133 | different types, to watch multiple paths. If the empty string | |
134 | is assigned to any of these options, the list of paths to | |
135 | watch is reset, and any prior assignments of these options | |
136 | will not have any effect.</para> | |
137 | ||
138 | <para>If a path already exists (in case of | |
139 | <varname>PathExists=</varname> and | |
140 | <varname>PathExistsGlob=</varname>) or a directory already is | |
141 | not empty (in case of <varname>DirectoryNotEmpty=</varname>) | |
142 | at the time the path unit is activated, then the configured | |
143 | unit is immediately activated as well. Something similar does | |
144 | not apply to <varname>PathChanged=</varname> and | |
145 | <varname>PathModified=</varname>.</para> | |
146 | ||
147 | <para>If the path itself or any of the containing directories | |
148 | are not accessible, <command>systemd</command> will watch for | |
149 | permission changes and notice that conditions are satisfied | |
150 | when permissions allow that. </para></listitem> | |
151 | </varlistentry> | |
152 | <varlistentry> | |
153 | <term><varname>Unit=</varname></term> | |
154 | ||
155 | <listitem><para>The unit to activate when any of the | |
156 | configured paths changes. The argument is a unit name, whose | |
157 | suffix is not <literal>.path</literal>. If not specified, this | |
158 | value defaults to a service that has the same name as the path | |
159 | unit, except for the suffix. (See above.) It is recommended | |
160 | that the unit name that is activated and the unit name of the | |
161 | path unit are named identical, except for the | |
162 | suffix.</para></listitem> | |
163 | </varlistentry> | |
164 | <varlistentry> | |
165 | <term><varname>MakeDirectory=</varname></term> | |
166 | ||
167 | <listitem><para>Takes a boolean argument. If true, the | |
168 | directories to watch are created before watching. This option | |
169 | is ignored for <varname>PathExists=</varname> settings. | |
170 | Defaults to <option>false</option>.</para></listitem> | |
171 | </varlistentry> | |
172 | <varlistentry> | |
173 | <term><varname>DirectoryMode=</varname></term> | |
174 | ||
175 | <listitem><para>If <varname>MakeDirectory=</varname> is | |
176 | enabled, use the mode specified here to create the directories | |
177 | in question. Takes an access mode in octal notation. Defaults | |
178 | to <option>0755</option>.</para></listitem> | |
179 | </varlistentry> | |
180 | </variablelist> | |
181 | </refsect1> | |
182 | ||
183 | <refsect1> | |
184 | <title>See Also</title> | |
185 | <para> | |
186 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
187 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
188 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
189 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
3ba3a79d | 190 | <citerefentry project='man-pages'><refentrytitle>inotify</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
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191 | <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
192 | </para> | |
193 | </refsect1> | |
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194 | |
195 | </refentry> |