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>
116 <para>The type consists of a single letter and
117 optionally an exclamation mark.</para>
119 <para>The following line types are understood:</para>
123 <term><varname>f</varname></term>
124 <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>
128 <term><varname>F</varname></term>
129 <listitem><para>Create or truncate a file. If the argument parameter is given, it will be written to the file.</para></listitem>
133 <term><varname>w</varname></term>
134 <listitem><para>Write the argument parameter to a file, if the file exists.
135 Lines of this type accept shell-style globs in place of normal path
136 names. The argument parameter will be written without a trailing
137 newline. C-style backslash escapes are interpreted.</para></listitem>
141 <term><varname>d</varname></term>
142 <listitem><para>Create a directory if it does not exist yet.</para></listitem>
146 <term><varname>D</varname></term>
147 <listitem><para>Create or empty a directory.</para></listitem>
151 <term><varname>p</varname></term>
152 <listitem><para>Create a named pipe (FIFO) if it does not exist yet.</para></listitem>
156 <term><varname>L</varname></term>
157 <listitem><para>Create a symlink if it does not exist yet.</para></listitem>
161 <term><varname>c</varname></term>
162 <listitem><para>Create a character device node if it does not exist yet.</para></listitem>
166 <term><varname>b</varname></term>
167 <listitem><para>Create a block device node if it does not exist yet.</para></listitem>
171 <term><varname>m</varname></term>
172 <listitem><para>If the
173 specified file path exists,
174 adjust its access mode, group
175 and user to the specified
176 values and reset the SELinux
177 security context. If it does not exist, do
178 nothing.</para></listitem>
182 <term><varname>x</varname></term>
183 <listitem><para>Ignore a path
184 during cleaning. Use this type
185 to exclude paths from clean-up
186 as controlled with the Age
187 parameter. Note that lines of
188 this type do not influence the
189 effect of <varname>r</varname>
190 or <varname>R</varname> lines.
191 Lines of this type accept
192 shell-style globs in place of
198 <term><varname>X</varname></term>
199 <listitem><para>Ignore a path
200 during cleaning. Use this type
201 to exclude paths from clean-up
202 as controlled with the Age
204 <varname>x</varname>, this
205 parameter will not exclude the
207 directory, but only directory
208 itself. Note that lines of
209 this type do not influence the
210 effect of <varname>r</varname>
211 or <varname>R</varname> lines.
212 Lines of this type accept
213 shell-style globs in place of
219 <term><varname>r</varname></term>
220 <listitem><para>Remove a file
221 or directory if it exists.
222 This may not be used to remove
223 non-empty directories, use
224 <varname>R</varname> for that.
225 Lines of this type accept
226 shell-style globs in place of
228 names.</para></listitem>
232 <term><varname>R</varname></term>
233 <listitem><para>Recursively
234 remove a path and all its
235 subdirectories (if it is a
236 directory). Lines of this type
237 accept shell-style globs in
239 names.</para></listitem>
243 <term><varname>z</varname></term>
244 <listitem><para>Restore
245 SELinux security context
246 and set ownership and access
247 mode of a file or directory if
248 it exists. Lines of this type
249 accept shell-style globs in
250 place of normal path names.
255 <term><varname>Z</varname></term>
256 <listitem><para>Recursively
257 restore SELinux security
259 ownership and access mode of a
261 subdirectories (if it is a
262 directory). Lines of this type
263 accept shell-style globs in
265 names.</para></listitem>
269 <para>If the exclamation mark is used, this
270 line is only safe of execute during boot, and
271 can break a running system. Lines without the
272 exclamation mark are presumed to be safe to
273 execute at any time, e.g. on package upgrades.
274 <command>systemd-tmpfiles</command> will
275 execute line with an exclamation mark only if
276 option <option>--boot</option> is given.
281 # Make sure these are created by default so that nobody else can
282 d /tmp/.X11-unix 1777 root root 10d
284 # Unlink the X11 lock files
285 r! /tmp/.X[0-9]*-lock
287 The second line in contrast to the first one
288 would break a running system, and will only be
289 executed with <option>--boot</option>.</para>
295 <para>The file system path specification supports simple specifier
296 expansion. The following expansions are
300 <title>Specifiers available</title>
301 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
302 <colspec colname="spec" />
303 <colspec colname="mean" />
304 <colspec colname="detail" />
307 <entry>Specifier</entry>
308 <entry>Meaning</entry>
309 <entry>Details</entry>
314 <entry><literal>%m</literal></entry>
315 <entry>Machine ID</entry>
316 <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>
319 <entry><literal>%b</literal></entry>
320 <entry>Boot ID</entry>
321 <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
324 <entry><literal>%H</literal></entry>
325 <entry>Host name</entry>
326 <entry>The hostname of the running system.</entry>
329 <entry><literal>%v</literal></entry>
330 <entry>Kernel release</entry>
331 <entry>Identical to <command>uname -r</command> output.</entry>
334 <entry><literal>%%</literal></entry>
335 <entry>Escaped %</entry>
336 <entry>Single percent sign.</entry>
346 <para>The file access mode to use when
347 creating this file or directory. If omitted or
348 when set to -, the default is used: 0755 for
349 directories, 0644 for all other file objects.
350 For <varname>z</varname>, <varname>Z</varname>
351 lines, if omitted or when set to
352 <literal>-</literal>, the file access mode
353 will not be modified. This parameter is
354 ignored for <varname>x</varname>,
355 <varname>r</varname>, <varname>R</varname>,
356 <varname>L</varname> lines.</para>
360 <title>UID, GID</title>
362 <para>The user and group to use for this file
363 or directory. This may either be a numeric
364 user/group ID or a user or group name. If
365 omitted or when set to <literal>-</literal>,
366 the default 0 (root) is used. For
367 <varname>z</varname>, <varname>Z</varname>
368 lines, when omitted or when set to -, the file
369 ownership will not be modified. These
370 parameters are ignored for
371 <varname>x</varname>, <varname>r</varname>,
372 <varname>R</varname>, <varname>L</varname>
378 <para>The date field, when set, is used to
379 decide what files to delete when cleaning. If
380 a file or directory is older than the current
381 time minus the age field, it is deleted. The
382 field format is a series of integers each
383 followed by one of the following
384 postfixes for the respective time units:</para>
388 <term><varname>s</varname></term>
389 <term><varname>min</varname></term>
390 <term><varname>h</varname></term>
391 <term><varname>d</varname></term>
392 <term><varname>w</varname></term>
393 <term><varname>ms</varname></term>
394 <term><varname>m</varname></term>
395 <term><varname>us</varname></term></varlistentry>
398 <para>If multiple integers and units are specified, the time
399 values are summed up. If an integer is given without a unit,
403 <para>When the age is set to zero, the files are cleaned
404 unconditionally.</para>
406 <para>The age field only applies to lines
407 starting with <varname>d</varname>,
408 <varname>D</varname>, and
409 <varname>x</varname>. If omitted or set to
410 <literal>-</literal>, no automatic clean-up is
413 <para>If the age field starts with a tilde
414 character <literal>~</literal>, the clean-up
415 is only applied to files and directories one
416 level inside the directory specified, but not
417 the files and directories immediately inside
422 <title>Argument</title>
424 <para>For <varname>L</varname> lines
425 determines the destination path of the
426 symlink. For <varname>c</varname>,
427 <varname>b</varname> determines the
428 major/minor of the device node, with major and
429 minor formatted as integers, separated by
430 <literal>:</literal>, e.g.
431 <literal>1:3</literal>. For
432 <varname>f</varname>, <varname>F</varname>,
433 and <varname>w</varname> may be used to
434 specify a short string that is written to the
435 file, suffixed by a newline. Ignored for all
442 <title>Example</title>
444 <title>/etc/tmpfiles.d/screen.conf example</title>
445 <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
447 <programlisting>d /var/run/screens 1777 root root 10d
448 d /var/run/uscreens 0755 root root 10d12h</programlisting>
451 <title>/etc/tmpfiles.d/abrt.conf example</title>
452 <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
454 <programlisting>d /var/tmp/abrt 0755 abrt abrt
455 x /var/tmp/abrt/*</programlisting>
460 <title>See Also</title>
462 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
463 <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
464 <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>