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
11 the Free Software Foundation; either version 2.1 of the License, or
12 (at your option) any later version.
14 systemd is distributed in the hope that it will be useful, but
15 WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 Lesser General Public License for more details.
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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
71 <filename><replaceable>package</replaceable>.conf</filename>
73 <filename><replaceable>package</replaceable>-<replaceable>part</replaceable>.conf</filename>.
74 The second variant should be used when it is desirable
75 to make it easy to override just this part of
78 <para>Files in <filename>/etc/tmpfiles.d</filename>
79 override files with the same name in
80 <filename>/usr/lib/tmpfiles.d</filename> and
81 <filename>/run/tmpfiles.d</filename>. Files in
82 <filename>/run/tmpfiles.d</filename> override files
84 <filename>/usr/lib/tmpfiles.d</filename>. Packages
85 should install their configuration files in
86 <filename>/usr/lib/tmpfiles.d</filename>. Files in
87 <filename>/etc/tmpfiles.d</filename> are reserved for
88 the local administrator, who may use this logic to
89 override the configuration files installed by vendor
90 packages. All configuration files are sorted by their
91 filename in lexicographic order, regardless of which
92 of the directories they reside in. If multiple files
93 specify the same path, the entry in the file with the
94 lexicographically earliest name will be applied, all
95 all other conflicting entries logged as errors.</para>
97 <para>If the administrator wants to disable a
98 configuration file supplied by the vendor, the
99 recommended way is to place a symlink to
100 <filename>/dev/null</filename> in
101 <filename>/etc/tmpfiles.d/</filename> bearing the
102 same filename.</para>
104 <para>The configuration format is one line per path
105 containing type, path, mode, ownership, age, and argument
108 <programlisting>#Type Path Mode UID GID Age Argument
109 d /run/user 0755 root root 10d -
110 L /tmp/foobar - - - - /dev/null</programlisting>
115 <para>The type consists of a single letter and
116 optionally an exclamation mark.</para>
118 <para>The following line types are understood:</para>
122 <term><varname>f</varname></term>
123 <listitem><para>Create a file if it does not exist yet. If the argument parameter is given, it will be written to the file.</para></listitem>
127 <term><varname>F</varname></term>
128 <listitem><para>Create or truncate a file. If the argument parameter is given, it will be written to the file.</para></listitem>
132 <term><varname>w</varname></term>
133 <listitem><para>Write the argument parameter to a file, if the file exists.
134 Lines of this type accept shell-style globs in place of normal path
135 names. The argument parameter will be written without a trailing
136 newline. C-style backslash escapes are interpreted.</para></listitem>
140 <term><varname>d</varname></term>
141 <listitem><para>Create a directory if it does not exist yet.</para></listitem>
145 <term><varname>D</varname></term>
146 <listitem><para>Create or empty a directory.</para></listitem>
150 <term><varname>p</varname></term>
151 <listitem><para>Create a named pipe (FIFO) if it does not exist yet.</para></listitem>
155 <term><varname>L</varname></term>
156 <listitem><para>Create a symlink if it does not exist yet.</para></listitem>
160 <term><varname>c</varname></term>
161 <listitem><para>Create a character device node if it does not exist yet.</para></listitem>
165 <term><varname>b</varname></term>
166 <listitem><para>Create a block device node if it does not exist yet.</para></listitem>
170 <term><varname>m</varname></term>
171 <listitem><para>If the
172 specified file path exists,
173 adjust its access mode, group
174 and user to the specified
175 values and reset the SELinux
176 security context. If it does not exist, do
177 nothing.</para></listitem>
181 <term><varname>x</varname></term>
182 <listitem><para>Ignore a path
183 during cleaning. Use this type
184 to exclude paths from clean-up
185 as controlled with the Age
186 parameter. Note that lines of
187 this type do not influence the
188 effect of <varname>r</varname>
189 or <varname>R</varname> lines.
190 Lines of this type accept
191 shell-style globs in place of
197 <term><varname>X</varname></term>
198 <listitem><para>Ignore a path
199 during cleaning. Use this type
200 to exclude paths from clean-up
201 as controlled with the Age
203 <varname>x</varname>, this
204 parameter will not exclude the
206 directory, but only directory
207 itself. Note that lines of
208 this type do not influence the
209 effect of <varname>r</varname>
210 or <varname>R</varname> lines.
211 Lines of this type accept
212 shell-style globs in place of
218 <term><varname>r</varname></term>
219 <listitem><para>Remove a file
220 or directory if it exists.
221 This may not be used to remove
222 non-empty directories, use
223 <varname>R</varname> for that.
224 Lines of this type accept
225 shell-style globs in place of
227 names.</para></listitem>
231 <term><varname>R</varname></term>
232 <listitem><para>Recursively
233 remove a path and all its
234 subdirectories (if it is a
235 directory). Lines of this type
236 accept shell-style globs in
238 names.</para></listitem>
242 <term><varname>z</varname></term>
243 <listitem><para>Restore
244 SELinux security context
245 and set ownership and access
246 mode of a file or directory if
247 it exists. Lines of this type
248 accept shell-style globs in
249 place of normal path names.
254 <term><varname>Z</varname></term>
255 <listitem><para>Recursively
256 restore SELinux security
258 ownership and access mode of a
260 subdirectories (if it is a
261 directory). Lines of this type
262 accept shell-style globs in
264 names.</para></listitem>
268 <para>If the exclamation mark is used, this
269 line is only safe of execute during boot, and
270 can break a running system. Lines without the
271 exclamation mark are presumed to be safe to
272 execute at any time, e.g. on package upgrades.
273 <command>systemd-tmpfiles</command> will
274 execute line with an exclamation mark only if
275 option <option>--boot</option> is given.
279 <programlisting># Make sure these are created by default so that nobody else can
280 d /tmp/.X11-unix 1777 root root 10d
282 # Unlink the X11 lock files
283 r! /tmp/.X[0-9]*-lock</programlisting>
284 The second line in contrast to the first one
285 would break a running system, and will only be
286 executed with <option>--boot</option>.</para>
292 <para>The file system path specification supports simple specifier
293 expansion. The following expansions are
297 <title>Specifiers available</title>
298 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
299 <colspec colname="spec" />
300 <colspec colname="mean" />
301 <colspec colname="detail" />
304 <entry>Specifier</entry>
305 <entry>Meaning</entry>
306 <entry>Details</entry>
311 <entry><literal>%m</literal></entry>
312 <entry>Machine ID</entry>
313 <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>
316 <entry><literal>%b</literal></entry>
317 <entry>Boot ID</entry>
318 <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
321 <entry><literal>%H</literal></entry>
322 <entry>Host name</entry>
323 <entry>The hostname of the running system.</entry>
326 <entry><literal>%v</literal></entry>
327 <entry>Kernel release</entry>
328 <entry>Identical to <command>uname -r</command> output.</entry>
331 <entry><literal>%%</literal></entry>
332 <entry>Escaped %</entry>
333 <entry>Single percent sign.</entry>
343 <para>The file access mode to use when
344 creating this file or directory. If omitted or
345 when set to -, the default is used: 0755 for
346 directories, 0644 for all other file objects.
347 For <varname>z</varname>, <varname>Z</varname>
348 lines, if omitted or when set to
349 <literal>-</literal>, the file access mode
350 will not be modified. This parameter is
351 ignored for <varname>x</varname>,
352 <varname>r</varname>, <varname>R</varname>,
353 <varname>L</varname> lines.</para>
357 <title>UID, GID</title>
359 <para>The user and group to use for this file
360 or directory. This may either be a numeric
361 user/group ID or a user or group name. If
362 omitted or when set to <literal>-</literal>,
363 the default 0 (root) is used. For
364 <varname>z</varname>, <varname>Z</varname>
365 lines, when omitted or when set to -, the file
366 ownership will not be modified. These
367 parameters are ignored for
368 <varname>x</varname>, <varname>r</varname>,
369 <varname>R</varname>, <varname>L</varname>
375 <para>The date field, when set, is used to
376 decide what files to delete when cleaning. If
377 a file or directory is older than the current
378 time minus the age field, it is deleted. The
379 field format is a series of integers each
380 followed by one of the following
381 postfixes for the respective time units:</para>
385 <term><varname>s</varname></term>
386 <term><varname>min</varname></term>
387 <term><varname>h</varname></term>
388 <term><varname>d</varname></term>
389 <term><varname>w</varname></term>
390 <term><varname>ms</varname></term>
391 <term><varname>m</varname></term>
392 <term><varname>us</varname></term></varlistentry>
395 <para>If multiple integers and units are specified, the time
396 values are summed up. If an integer is given without a unit,
400 <para>When the age is set to zero, the files are cleaned
401 unconditionally.</para>
403 <para>The age field only applies to lines
404 starting with <varname>d</varname>,
405 <varname>D</varname>, and
406 <varname>x</varname>. If omitted or set to
407 <literal>-</literal>, no automatic clean-up is
410 <para>If the age field starts with a tilde
411 character <literal>~</literal>, the clean-up
412 is only applied to files and directories one
413 level inside the directory specified, but not
414 the files and directories immediately inside
419 <title>Argument</title>
421 <para>For <varname>L</varname> lines
422 determines the destination path of the
423 symlink. For <varname>c</varname>,
424 <varname>b</varname> determines the
425 major/minor of the device node, with major and
426 minor formatted as integers, separated by
427 <literal>:</literal>, e.g.
428 <literal>1:3</literal>. For
429 <varname>f</varname>, <varname>F</varname>,
430 and <varname>w</varname> may be used to
431 specify a short string that is written to the
432 file, suffixed by a newline. Ignored for all
439 <title>Example</title>
441 <title>/etc/tmpfiles.d/screen.conf example</title>
442 <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
444 <programlisting>d /var/run/screens 1777 root root 10d
445 d /var/run/uscreens 0755 root root 10d12h</programlisting>
448 <title>/etc/tmpfiles.d/abrt.conf example</title>
449 <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
451 <programlisting>d /var/tmp/abrt 0755 abrt abrt
452 x /var/tmp/abrt/*</programlisting>
457 <title>See Also</title>
459 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
460 <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
461 <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>