3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
5 This file is part of systemd.
7 Copyright 2010 Brandon Philips
9 systemd is free software; you can redistribute it and/or modify it
10 under the terms of the GNU Lesser General Public License as published by
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14 systemd is distributed in the hope that it will be useful, but
15 WITHOUT ANY WARRANTY; without even the implied warranty of
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22 <refentry id="tmpfiles.d">
25 <title>tmpfiles.d</title>
26 <productname>systemd</productname>
30 <contrib>Documentation</contrib>
31 <firstname>Brandon</firstname>
32 <surname>Philips</surname>
33 <email>brandon@ifup.org</email>
39 <refentrytitle>tmpfiles.d</refentrytitle>
40 <manvolnum>5</manvolnum>
44 <refname>tmpfiles.d</refname>
45 <refpurpose>Configuration for creation, deletion and
46 cleaning of volatile and temporary files</refpurpose>
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>
56 <title>Description</title>
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>
67 <title>Configuration Format</title>
69 <para>Each configuration file shall be named in the
70 style of <filename><package>.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>
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
95 <para>The configuration format is one line per path
96 containing action, path, mode, ownership, age and argument
99 <programlisting>Type Path Mode UID GID Age Argument
100 d /run/user 0755 root root 10d -
101 L /tmp/foobar - - - - /dev/null</programlisting>
107 <para>The following line types are understood:</para>
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>
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>
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>
129 <term><varname>d</varname></term>
130 <listitem><para>Create a directory if it does not exist yet</para></listitem>
134 <term><varname>D</varname></term>
135 <listitem><para>Create or empty a directory</para></listitem>
139 <term><varname>p</varname></term>
140 <listitem><para>Create a named pipe (FIFO) if it does not exist yet</para></listitem>
144 <term><varname>L</varname></term>
145 <listitem><para>Create a symlink if it does not exist yet</para></listitem>
149 <term><varname>c</varname></term>
150 <listitem><para>Create a character device node if it does not exist yet</para></listitem>
154 <term><varname>b</varname></term>
155 <listitem><para>Create a block device node if it does not exist yet</para></listitem>
159 <term><varname>m</varname></term>
160 <listitem><para>If the
161 specified file path exists
162 adjust its access mode, group
163 and user to the specified
164 values and reset the SELinux
165 label. If it doesn't exist do
166 nothing.</para></listitem>
170 <term><varname>x</varname></term>
171 <listitem><para>Ignore a path
172 during cleaning. Use this type
173 to exclude paths from clean-up
174 as controlled with the Age
175 parameter. Note that lines of
176 this type do not influence the
177 effect of r or R lines. Lines
179 shell-style globs in place of
181 names.</para></listitem>
185 <term><varname>X</varname></term>
186 <listitem><para>Ignore a path
187 during cleanup. Use this type
188 to prevent path removal as
189 controlled with the Age parameter.
190 Note that if path is a directory,
191 content of a directory is not
192 excluded from clean-up, only
193 directory itself. Lines of this
194 type accept shell-style globs
195 in place of normal path
196 names.</para></listitem>
200 <term><varname>r</varname></term>
201 <listitem><para>Remove a file
203 exists. This may not be used
205 directories, use R for
206 that. Lines of this type
207 accept shell-style globs in
209 names.</para></listitem>
213 <term><varname>R</varname></term>
214 <listitem><para>Recursively
215 remove a path and all its
216 subdirectories (if it is a
217 directory). Lines of this type
218 accept shell-style globs in
220 names.</para></listitem>
224 <term><varname>z</varname></term>
225 <listitem><para>Restore
226 SELinux security context label
227 and set ownership and access
228 mode of a file or directory if
229 it exists. Lines of this type
230 accept shell-style globs in
231 place of normal path names.
236 <term><varname>Z</varname></term>
237 <listitem><para>Recursively
238 restore SELinux security
239 context label and set
240 ownership and access mode of a
242 subdirectories (if it is a
243 directory). Lines of this type
244 accept shell-style globs in
246 names.</para></listitem>
254 <para>The file system path specification supports simple specifier
255 expansion. The following expansions are
259 <title>Specifiers available</title>
260 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
261 <colspec colname="spec" />
262 <colspec colname="mean" />
263 <colspec colname="detail" />
266 <entry>Specifier</entry>
267 <entry>Meaning</entry>
268 <entry>Details</entry>
273 <entry><literal>%m</literal></entry>
274 <entry>Machine ID</entry>
275 <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>
278 <entry><literal>%b</literal></entry>
279 <entry>Boot ID</entry>
280 <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
283 <entry><literal>%H</literal></entry>
284 <entry>Host name</entry>
285 <entry>The hostname of the running system.</entry>
288 <entry><literal>%v</literal></entry>
289 <entry>Kernel release</entry>
290 <entry>Identical to <command>uname -r</command> output.</entry>
293 <entry><literal>%%</literal></entry>
294 <entry>Escaped %</entry>
295 <entry>Single percent sign.</entry>
305 <para>The file access mode to use when
306 creating this file or directory. If omitted or
307 when set to -, the default is used: 0755 for
308 directories, 0644 for all other file
309 objects. For z, Z lines, if omitted or when set
310 to -, the file access mode will not be
311 modified. This parameter is ignored for x, r,
316 <title>UID, GID</title>
318 <para>The user and group to use for this file
319 or directory. This may either be a numeric
320 user/group ID or a user or group name. If
321 omitted or when set to -, the default 0 (root)
322 is used. For z, Z lines, when omitted or when set to -,
323 the file ownership will not be modified.
324 These parameters are ignored for x, r, R, L lines.</para>
329 <para>The date field, when set, is used to
330 decide what files to delete when cleaning. If
331 a file or directory is older than the current
332 time minus the age field, it is deleted. The
333 field format is a series of integers each
334 followed by one of the following
335 postfixes for the respective time units:</para>
339 <term><varname>s</varname></term>
340 <term><varname>min</varname></term>
341 <term><varname>h</varname></term>
342 <term><varname>d</varname></term>
343 <term><varname>w</varname></term>
344 <term><varname>ms</varname></term>
345 <term><varname>m</varname></term>
346 <term><varname>us</varname></term></varlistentry>
349 <para>If multiple integers and units are specified, the time
350 values are summed up. If an integer is given without a unit,
354 <para>When the age is set to zero, the files are cleaned
355 unconditionally.</para>
357 <para>The age field only applies to lines starting with
358 d, D and x. If omitted or set to -, no automatic clean-up
361 <para>If the age field starts with a tilde
362 character (~), the clean-up is only applied to
363 files and directories one level inside the
364 directory specified, but not the files and
365 directories immediately inside it.</para>
369 <title>Argument</title>
371 <para>For L lines determines the destination
372 path of the symlink. For c, b determines the
373 major/minor of the device node, with major and
374 minor formatted as integers, separated by :,
375 e.g. "1:3". For f, F, w may be used to specify
376 a short string that is written to the file,
377 suffixed by a newline. Ignored for all other
384 <title>Example</title>
386 <title>/etc/tmpfiles.d/screen.conf example</title>
387 <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
389 <programlisting>d /var/run/screens 1777 root root 10d
390 d /var/run/uscreens 0755 root root 10d12h</programlisting>
393 <title>/etc/tmpfiles.d/abrt.conf example</title>
394 <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
396 <programlisting>d /var/tmp/abrt 0755 abrt abrt
397 x /var/tmp/abrt/*</programlisting>
402 <title>See Also</title>
404 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
405 <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
406 <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>