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tmpfiles: support simple specifier expansion for specified paths
[elogind.git] / man / tmpfiles.d.xml
1 <?xml version="1.0"?>
2 <!--*-nxml-*-->
3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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7   Copyright 2010 Brandon Philips
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22 <refentry id="tmpfiles.d">
23
24         <refentryinfo>
25                 <title>tmpfiles.d</title>
26                 <productname>systemd</productname>
27
28                 <authorgroup>
29                         <author>
30                                 <contrib>Documentation</contrib>
31                                 <firstname>Brandon</firstname>
32                                 <surname>Philips</surname>
33                                 <email>brandon@ifup.org</email>
34                         </author>
35                 </authorgroup>
36         </refentryinfo>
37
38         <refmeta>
39                 <refentrytitle>tmpfiles.d</refentrytitle>
40                 <manvolnum>5</manvolnum>
41         </refmeta>
42
43         <refnamediv>
44                 <refname>tmpfiles.d</refname>
45                 <refpurpose>Configuration for creation, deletion and
46                 cleaning of volatile and temporary files</refpurpose>
47         </refnamediv>
48
49         <refsynopsisdiv>
50                 <para><filename>/etc/tmpfiles.d/*.conf</filename></para>
51                 <para><filename>/run/tmpfiles.d/*.conf</filename></para>
52                 <para><filename>/usr/lib/tmpfiles.d/*.conf</filename></para>
53         </refsynopsisdiv>
54
55         <refsect1>
56                 <title>Description</title>
57
58                 <para><command>systemd-tmpfiles</command> uses the
59                 configuration files from the above directories to describe the
60                 creation, cleaning and removal of volatile and
61                 temporary files and directories which usually reside
62                 in directories such as <filename>/run</filename>
63                 or <filename>/tmp</filename>.</para>
64         </refsect1>
65
66         <refsect1>
67                 <title>Configuration Format</title>
68
69                 <para>Each configuration file shall be named in the
70                 style of <filename>&lt;package&gt;.conf</filename>.
71                 Files in <filename>/etc/</filename> override files
72                 with the same name in <filename>/usr/lib/</filename>
73                 and <filename>/run/</filename>.  Files in
74                 <filename>/run/</filename> override files with the same
75                 name in <filename>/usr/lib/</filename>. Packages
76                 should install their configuration files in
77                 <filename>/usr/lib/</filename>. Files in
78                 <filename>/etc/</filename> are reserved for the local
79                 administrator, who may use this logic to override the
80                 configuration files installed by vendor packages. All
81                 configuration files are sorted by their filename in
82                 lexicographic order, regardless in which of the
83                 directories they reside. If multiple files specify the
84                 same path, the entry in the file with the lexicographically
85                 earliest name will be applied, all all other conflicting
86                 entries logged as errors.</para>
87
88                 <para>If the administrator wants to disable a
89                 configuration file supplied by the vendor, the
90                 recommended way is to place a symlink to
91                 <filename>/dev/null</filename> in
92                 <filename>/etc/tmpfiles.d/</filename> bearing the
93                 same filename.</para>
94
95                 <para>The configuration format is one line per path
96                 containing action, path, mode, ownership, age and argument
97                 fields:</para>
98
99                 <programlisting>Type Path        Mode UID  GID  Age Argument
100 d    /run/user   0755 root root 10d -
101 L    /tmp/foobar -    -    -    -   /dev/null</programlisting>
102
103
104                 <refsect2>
105                         <title>Type</title>
106
107                         <para>The following line types are understood:</para>
108
109                         <variablelist>
110                                 <varlistentry>
111                                         <term><varname>f</varname></term>
112                                         <listitem><para>Create a file if it does not exist yet (optionally writing a short string into it, if the argument parameter is passed)</para></listitem>
113                                 </varlistentry>
114
115                                 <varlistentry>
116                                         <term><varname>F</varname></term>
117                                         <listitem><para>Create or truncate a file (optionally writing a short string into it, if the argument parameter is passed)</para></listitem>
118                                 </varlistentry>
119
120                                 <varlistentry>
121                                         <term><varname>w</varname></term>
122                                         <listitem><para>Write the argument parameter to a file, if the file exists.
123                                             Lines of this type accept shell-style globs in place of normal path
124                                             names. The argument parameter will be written without a trailing
125                                             newline. C-style backslash escapes are interpreted.</para></listitem>
126                                 </varlistentry>
127
128                                 <varlistentry>
129                                         <term><varname>d</varname></term>
130                                         <listitem><para>Create a directory if it does not exist yet</para></listitem>
131                                 </varlistentry>
132
133                                 <varlistentry>
134                                         <term><varname>D</varname></term>
135                                         <listitem><para>Create or empty a directory</para></listitem>
136                                 </varlistentry>
137
138                                 <varlistentry>
139                                         <term><varname>p</varname></term>
140                                         <listitem><para>Create a named pipe (FIFO) if it does not exist yet</para></listitem>
141                                 </varlistentry>
142
143                                 <varlistentry>
144                                         <term><varname>L</varname></term>
145                                         <listitem><para>Create a symlink if it does not exist yet</para></listitem>
146                                 </varlistentry>
147
148                                 <varlistentry>
149                                         <term><varname>c</varname></term>
150                                         <listitem><para>Create a character device node if it does not exist yet</para></listitem>
151                                 </varlistentry>
152
153                                 <varlistentry>
154                                         <term><varname>b</varname></term>
155                                         <listitem><para>Create a block device node if it does not exist yet</para></listitem>
156                                 </varlistentry>
157
158                                 <varlistentry>
159                                         <term><varname>x</varname></term>
160                                         <listitem><para>Ignore a path
161                                         during cleaning. Use this type
162                                         to exclude paths from clean-up
163                                         as controlled with the Age
164                                         parameter. Note that lines of
165                                         this type do not influence the
166                                         effect of r or R lines. Lines
167                                         of this type accept
168                                         shell-style globs in place of
169                                         normal path
170                                         names.</para></listitem>
171                                 </varlistentry>
172
173                                 <varlistentry>
174                                         <term><varname>X</varname></term>
175                                         <listitem><para>Ignore a path
176                                         during cleanup. Use this type
177                                         to prevent path removal as
178                                         controlled with the Age parameter.
179                                         Note that if path is a directory,
180                                         content of a directory is not
181                                         excluded from clean-up, only
182                                         directory itself. Lines of this
183                                         type accept shell-style globs
184                                         in place of normal path
185                                         names.</para></listitem>
186                                 </varlistentry>
187
188                                 <varlistentry>
189                                         <term><varname>r</varname></term>
190                                         <listitem><para>Remove a file
191                                         or directory if it
192                                         exists. This may not be used
193                                         to remove non-empty
194                                         directories, use R for
195                                         that. Lines of this type
196                                         accept shell-style globs in
197                                         place of normal path
198                                         names.</para></listitem>
199                                 </varlistentry>
200
201                                 <varlistentry>
202                                         <term><varname>R</varname></term>
203                                         <listitem><para>Recursively
204                                         remove a path and all its
205                                         subdirectories (if it is a
206                                         directory). Lines of this type
207                                         accept shell-style globs in
208                                         place of normal path
209                                         names.</para></listitem>
210                                 </varlistentry>
211
212                                 <varlistentry>
213                                         <term><varname>z</varname></term>
214                                         <listitem><para>Restore
215                                         SELinux security context label
216                                         and set ownership and access
217                                         mode of a file or directory if
218                                         it exists.  Lines of this type
219                                         accept shell-style globs in
220                                         place of normal path names.
221                                         </para></listitem>
222                                 </varlistentry>
223
224                                 <varlistentry>
225                                         <term><varname>Z</varname></term>
226                                         <listitem><para>Recursively
227                                         restore SELinux security
228                                         context label and set
229                                         ownership and access mode of a
230                                         path and all its
231                                         subdirectories (if it is a
232                                         directory). Lines of this type
233                                         accept shell-style globs in
234                                         place of normal path
235                                         names.</para></listitem>
236                                 </varlistentry>
237                         </variablelist>
238                 </refsect2>
239
240                 <refsect2>
241                         <title>Path</title>
242
243                         <para>The file system path specification supports simple specifier
244                         expansion. The following expansions are
245                         understood:</para>
246
247                         <table>
248                                 <title>Specifiers available</title>
249                                 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
250                                         <colspec colname="spec" />
251                                         <colspec colname="mean" />
252                                         <colspec colname="detail" />
253                                         <thead>
254                                                 <row>
255                                                         <entry>Specifier</entry>
256                                                         <entry>Meaning</entry>
257                                                         <entry>Details</entry>
258                                                 </row>
259                                         </thead>
260                                         <tbody>
261                                                 <row>
262                                                         <entry><literal>%m</literal></entry>
263                                                         <entry>Machine ID</entry>
264                                                         <entry>The machine ID of the running system, formatted as string. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</entry>
265                                                 </row>
266                                                 <row>
267                                                         <entry><literal>%b</literal></entry>
268                                                         <entry>Boot ID</entry>
269                                                         <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
270                                                 </row>
271                                                 <row>
272                                                         <entry><literal>%H</literal></entry>
273                                                         <entry>Host name</entry>
274                                                         <entry>The hostname of the running system.</entry>
275                                                 </row>
276                                                 <row>
277                                                         <entry><literal>%v</literal></entry>
278                                                         <entry>Kernel release</entry>
279                                                         <entry>Identical to <command>uname -r</command> output.</entry>
280                                                 </row>
281                                                 <row>
282                                                         <entry><literal>%%</literal></entry>
283                                                         <entry>Escaped %</entry>
284                                                         <entry>Single percent sign.</entry>
285                                                 </row>
286                                         </tbody>
287                                 </tgroup>
288                         </table>
289                 </refsect2>
290
291                 <refsect2>
292                         <title>Mode</title>
293
294                         <para>The file access mode to use when
295                         creating this file or directory. If omitted or
296                         when set to -, the default is used: 0755 for
297                         directories, 0644 for all other file
298                         objects. For z, Z lines, if omitted or when set
299                         to -, the file access mode will not be
300                         modified. This parameter is ignored for x, r,
301                         R, L lines.</para>
302                 </refsect2>
303
304                 <refsect2>
305                         <title>UID, GID</title>
306
307                         <para>The user and group to use for this file
308                         or directory. This may either be a numeric
309                         user/group ID or a user or group name. If
310                         omitted or when set to -, the default 0 (root)
311                         is used. For z, Z lines, when omitted or when set to -,
312                         the file ownership will not be modified.
313                         These parameters are ignored for x, r, R, L lines.</para>
314                 </refsect2>
315
316                 <refsect2>
317                         <title>Age</title>
318                         <para>The date field, when set, is used to
319                         decide what files to delete when cleaning. If
320                         a file or directory is older than the current
321                         time minus the age field, it is deleted. The
322                         field format is a series of integers each
323                         followed by one of the following
324                         postfixes for the respective time units:</para>
325
326                         <variablelist>
327                                 <varlistentry>
328                                 <term><varname>s</varname></term>
329                                 <term><varname>min</varname></term>
330                                 <term><varname>h</varname></term>
331                                 <term><varname>d</varname></term>
332                                 <term><varname>w</varname></term>
333                                 <term><varname>ms</varname></term>
334                                 <term><varname>m</varname></term>
335                                 <term><varname>us</varname></term></varlistentry>
336                         </variablelist>
337
338                         <para>If multiple integers and units are specified, the time
339                         values are summed up. If an integer is given without a unit,
340                         s is assumed.
341                         </para>
342
343                         <para>When the age is set to zero, the files are cleaned
344                         unconditionally.</para>
345
346                         <para>The age field only applies to lines starting with
347                         d, D and x. If omitted or set to -, no automatic clean-up
348                         is done.</para>
349
350                         <para>If the age field starts with a tilde
351                         character (~), the clean-up is only applied to
352                         files and directories one level inside the
353                         directory specified, but not the files and
354                         directories immediately inside it.</para>
355                 </refsect2>
356
357                 <refsect2>
358                         <title>Argument</title>
359
360                         <para>For L lines determines the destination
361                         path of the symlink. For c, b determines the
362                         major/minor of the device node, with major and
363                         minor formatted as integers, separated by :,
364                         e.g. "1:3". For f, F, w may be used to specify
365                         a short string that is written to the file,
366                         suffixed by a newline. Ignored for all other
367                         lines.</para>
368                 </refsect2>
369
370         </refsect1>
371
372         <refsect1>
373                 <title>Example</title>
374                 <example>
375                         <title>/etc/tmpfiles.d/screen.conf example</title>
376                         <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
377
378                         <programlisting>d /var/run/screens  1777 root root 10d
379 d /var/run/uscreens 0755 root root 10d12h</programlisting>
380                 </example>
381                 <example>
382                         <title>/etc/tmpfiles.d/abrt.conf example</title>
383                         <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
384
385                         <programlisting>d /var/tmp/abrt 0755 abrt abrt
386 x /var/tmp/abrt/*</programlisting>
387                 </example>
388         </refsect1>
389
390         <refsect1>
391                 <title>See Also</title>
392                 <para>
393                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
394                         <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
395                         <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>
396                 </para>
397         </refsect1>
398
399 </refentry>