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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 | <!-- | |
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6 | SPDX-License-Identifier: LGPL-2.1+ |
7 | ||
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8 | This file is part of systemd. |
9 | ||
10 | Copyright 2010 Lennart Poettering | |
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11 | --> |
12 | ||
13 | <refentry id="systemd.path"> | |
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14 | <refentryinfo> |
15 | <title>systemd.path</title> | |
16 | <productname>systemd</productname> | |
17 | ||
18 | <authorgroup> | |
19 | <author> | |
20 | <contrib>Developer</contrib> | |
21 | <firstname>Lennart</firstname> | |
22 | <surname>Poettering</surname> | |
23 | <email>lennart@poettering.net</email> | |
24 | </author> | |
25 | </authorgroup> | |
26 | </refentryinfo> | |
27 | ||
28 | <refmeta> | |
29 | <refentrytitle>systemd.path</refentrytitle> | |
30 | <manvolnum>5</manvolnum> | |
31 | </refmeta> | |
32 | ||
33 | <refnamediv> | |
34 | <refname>systemd.path</refname> | |
35 | <refpurpose>Path unit configuration</refpurpose> | |
36 | </refnamediv> | |
37 | ||
38 | <refsynopsisdiv> | |
39 | <para><filename><replaceable>path</replaceable>.path</filename></para> | |
40 | </refsynopsisdiv> | |
41 | ||
42 | <refsect1> | |
43 | <title>Description</title> | |
44 | ||
45 | <para>A unit configuration file whose name ends in | |
46 | <literal>.path</literal> encodes information about a path | |
47 | monitored by systemd, for path-based activation.</para> | |
48 | ||
49 | <para>This man page lists the configuration options specific to | |
50 | this unit type. See | |
51 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
52 | for the common options of all unit configuration files. The common | |
53 | configuration items are configured in the generic [Unit] and | |
54 | [Install] sections. The path specific configuration options are | |
55 | configured in the [Path] section.</para> | |
56 | ||
57 | <para>For each path file, a matching unit file must exist, | |
58 | describing the unit to activate when the path changes. By default, | |
59 | a service by the same name as the path (except for the suffix) is | |
60 | activated. Example: a path file <filename>foo.path</filename> | |
61 | activates a matching service <filename>foo.service</filename>. The | |
62 | unit to activate may be controlled by <varname>Unit=</varname> | |
63 | (see below).</para> | |
64 | ||
65 | <para>Internally, path units use the | |
3ba3a79d | 66 | <citerefentry project='man-pages'><refentrytitle>inotify</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
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67 | API to monitor file systems. Due to that, it suffers by the same |
68 | limitations as inotify, and for example cannot be used to monitor | |
69 | files or directories changed by other machines on remote NFS file | |
70 | systems.</para> | |
c129bd5d | 71 | </refsect1> |
798d3a52 | 72 | |
c129bd5d | 73 | <refsect1> |
45f09f93 JL |
74 | <title>Implicit Dependencies</title> |
75 | ||
76 | <para>The following dependencies are implicitly added:</para> | |
77 | ||
78 | <itemizedlist> | |
79 | <listitem><para>If a path unit is beneath another mount unit in the file | |
80 | system hierarchy, both a requirement and an ordering dependency | |
81 | between both units are created automatically.</para></listitem> | |
82 | ||
83 | <listitem><para>An implicit <varname>Before=</varname> dependency is added | |
84 | between a path unit and the unit it is supposed to activate.</para></listitem> | |
85 | </itemizedlist> | |
86 | </refsect1> | |
87 | ||
88 | <refsect1> | |
89 | <title>Default Dependencies</title> | |
90 | ||
91 | <para>The following dependencies are added unless <varname>DefaultDependencies=no</varname> is set:</para> | |
92 | ||
93 | <itemizedlist> | |
94 | <listitem><para>Path units will automatically have dependencies of type <varname>Before=</varname> on | |
95 | <filename>paths.target</filename>, | |
96 | dependencies of type <varname>After=</varname> and <varname>Requires=</varname> on | |
97 | <filename>sysinit.target</filename>, and have dependencies of type <varname>Conflicts=</varname> and | |
98 | <varname>Before=</varname> on <filename>shutdown.target</filename>. These ensure that path units are terminated | |
99 | cleanly prior to system shutdown. Only path units involved with early boot or late system shutdown should | |
100 | disable <varname>DefaultDependencies=</varname> option.</para></listitem> | |
101 | </itemizedlist> | |
102 | ||
103 | <para></para> | |
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104 | </refsect1> |
105 | ||
106 | <refsect1> | |
107 | <title>Options</title> | |
108 | ||
109 | <para>Path files must include a [Path] section, which carries | |
110 | information about the path(s) it monitors. The options specific to | |
111 | the [Path] section of path units are the following:</para> | |
112 | ||
113 | <variablelist class='unit-directives'> | |
114 | <varlistentry> | |
115 | <term><varname>PathExists=</varname></term> | |
116 | <term><varname>PathExistsGlob=</varname></term> | |
117 | <term><varname>PathChanged=</varname></term> | |
118 | <term><varname>PathModified=</varname></term> | |
119 | <term><varname>DirectoryNotEmpty=</varname></term> | |
120 | ||
121 | <listitem><para>Defines paths to monitor for certain changes: | |
122 | <varname>PathExists=</varname> may be used to watch the mere | |
123 | existence of a file or directory. If the file specified | |
124 | exists, the configured unit is activated. | |
125 | <varname>PathExistsGlob=</varname> works similar, but checks | |
126 | for the existence of at least one file matching the globbing | |
127 | pattern specified. <varname>PathChanged=</varname> may be used | |
128 | to watch a file or directory and activate the configured unit | |
129 | whenever it changes. It is not activated on every write to the | |
130 | watched file but it is activated if the file which was open | |
131 | for writing gets closed. <varname>PathModified=</varname> is | |
132 | similar, but additionally it is activated also on simple | |
133 | writes to the watched file. | |
134 | <varname>DirectoryNotEmpty=</varname> may be used to watch a | |
135 | directory and activate the configured unit whenever it | |
136 | contains at least one file.</para> | |
137 | ||
138 | <para>The arguments of these directives must be absolute file | |
139 | system paths.</para> | |
140 | ||
141 | <para>Multiple directives may be combined, of the same and of | |
142 | different types, to watch multiple paths. If the empty string | |
143 | is assigned to any of these options, the list of paths to | |
144 | watch is reset, and any prior assignments of these options | |
145 | will not have any effect.</para> | |
146 | ||
147 | <para>If a path already exists (in case of | |
148 | <varname>PathExists=</varname> and | |
149 | <varname>PathExistsGlob=</varname>) or a directory already is | |
150 | not empty (in case of <varname>DirectoryNotEmpty=</varname>) | |
151 | at the time the path unit is activated, then the configured | |
152 | unit is immediately activated as well. Something similar does | |
153 | not apply to <varname>PathChanged=</varname> and | |
154 | <varname>PathModified=</varname>.</para> | |
155 | ||
156 | <para>If the path itself or any of the containing directories | |
157 | are not accessible, <command>systemd</command> will watch for | |
158 | permission changes and notice that conditions are satisfied | |
159 | when permissions allow that. </para></listitem> | |
160 | </varlistentry> | |
161 | <varlistentry> | |
162 | <term><varname>Unit=</varname></term> | |
163 | ||
164 | <listitem><para>The unit to activate when any of the | |
165 | configured paths changes. The argument is a unit name, whose | |
166 | suffix is not <literal>.path</literal>. If not specified, this | |
167 | value defaults to a service that has the same name as the path | |
168 | unit, except for the suffix. (See above.) It is recommended | |
169 | that the unit name that is activated and the unit name of the | |
170 | path unit are named identical, except for the | |
171 | suffix.</para></listitem> | |
172 | </varlistentry> | |
173 | <varlistentry> | |
174 | <term><varname>MakeDirectory=</varname></term> | |
175 | ||
176 | <listitem><para>Takes a boolean argument. If true, the | |
177 | directories to watch are created before watching. This option | |
178 | is ignored for <varname>PathExists=</varname> settings. | |
179 | Defaults to <option>false</option>.</para></listitem> | |
180 | </varlistentry> | |
181 | <varlistentry> | |
182 | <term><varname>DirectoryMode=</varname></term> | |
183 | ||
184 | <listitem><para>If <varname>MakeDirectory=</varname> is | |
185 | enabled, use the mode specified here to create the directories | |
186 | in question. Takes an access mode in octal notation. Defaults | |
187 | to <option>0755</option>.</para></listitem> | |
188 | </varlistentry> | |
189 | </variablelist> | |
190 | </refsect1> | |
191 | ||
192 | <refsect1> | |
193 | <title>See Also</title> | |
194 | <para> | |
195 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
196 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
197 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
198 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
3ba3a79d | 199 | <citerefentry project='man-pages'><refentrytitle>inotify</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
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200 | <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
201 | </para> | |
202 | </refsect1> | |
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203 | |
204 | </refentry> |