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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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>
65 <para>Volatile and temporary files and directories are
66 those located in <filename>/run</filename> (and its
67 alias <filename>/var/run</filename>),
68 <filename>/tmp</filename>,
69 <filename>/var/tmp</filename>, the API file systems
70 such as <filename>/sys</filename> or
71 <filename>/proc</filename>, as well as some other
72 directories below <filename>/var</filename>.</para>
74 <para>System daemons frequently require private
75 runtime directories below <filename>/run</filename> to
76 place communication sockets and similar in. For these,
77 consider declaring them in their unit files using
78 <varname>RuntimeDirectory=</varname>
79 (see <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details),
80 if this is feasible.</para>
84 <title>Configuration Format</title>
86 <para>Each configuration file shall be named in the
88 <filename><replaceable>package</replaceable>.conf</filename>
90 <filename><replaceable>package</replaceable>-<replaceable>part</replaceable>.conf</filename>.
91 The second variant should be used when it is desirable
92 to make it easy to override just this part of
95 <para>Files in <filename>/etc/tmpfiles.d</filename>
96 override files with the same name in
97 <filename>/usr/lib/tmpfiles.d</filename> and
98 <filename>/run/tmpfiles.d</filename>. Files in
99 <filename>/run/tmpfiles.d</filename> override files
100 with the same name in
101 <filename>/usr/lib/tmpfiles.d</filename>. Packages
102 should install their configuration files in
103 <filename>/usr/lib/tmpfiles.d</filename>. Files in
104 <filename>/etc/tmpfiles.d</filename> are reserved for
105 the local administrator, who may use this logic to
106 override the configuration files installed by vendor
107 packages. All configuration files are sorted by their
108 filename in lexicographic order, regardless of which
109 of the directories they reside in. If multiple files
110 specify the same path, the entry in the file with the
111 lexicographically earliest name will be applied, all
112 all other conflicting entries logged as errors.</para>
114 <para>If the administrator wants to disable a
115 configuration file supplied by the vendor, the
116 recommended way is to place a symlink to
117 <filename>/dev/null</filename> in
118 <filename>/etc/tmpfiles.d/</filename> bearing the
119 same filename.</para>
121 <para>The configuration format is one line per path
122 containing type, path, mode, ownership, age, and argument
125 <programlisting>#Type Path Mode UID GID Age Argument
126 d /run/user 0755 root root 10d -
127 L /tmp/foobar - - - - /dev/null</programlisting>
132 <para>The type consists of a single letter and
133 optionally an exclamation mark.</para>
135 <para>The following line types are understood:</para>
139 <term><varname>f</varname></term>
140 <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>
144 <term><varname>F</varname></term>
145 <listitem><para>Create or truncate a file. If the argument parameter is given, it will be written to the file.</para></listitem>
149 <term><varname>w</varname></term>
150 <listitem><para>Write the argument parameter to a file, if the file exists.
151 Lines of this type accept shell-style globs in place of normal path
152 names. The argument parameter will be written without a trailing
153 newline. C-style backslash escapes are interpreted.</para></listitem>
157 <term><varname>d</varname></term>
158 <listitem><para>Create a directory if it does not exist yet.</para></listitem>
162 <term><varname>D</varname></term>
163 <listitem><para>Create or empty a directory.</para></listitem>
167 <term><varname>p</varname></term>
168 <listitem><para>Create a named pipe (FIFO) if it does not exist yet.</para></listitem>
172 <term><varname>L</varname></term>
173 <listitem><para>Create a symlink if it does not exist yet.</para></listitem>
177 <term><varname>c</varname></term>
178 <listitem><para>Create a character device node if it does not exist yet.</para></listitem>
182 <term><varname>b</varname></term>
183 <listitem><para>Create a block device node if it does not exist yet.</para></listitem>
187 <term><varname>m</varname></term>
188 <listitem><para>If the
189 specified file path exists,
190 adjust its access mode, group
191 and user to the specified
192 values and reset the SELinux
193 security context. If it does not exist, do
194 nothing.</para></listitem>
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
203 parameter. Note that lines of
204 this type do not influence the
205 effect of <varname>r</varname>
206 or <varname>R</varname> lines.
207 Lines of this type accept
208 shell-style globs in place of
214 <term><varname>X</varname></term>
215 <listitem><para>Ignore a path
216 during cleaning. Use this type
217 to exclude paths from clean-up
218 as controlled with the Age
220 <varname>x</varname>, this
221 parameter will not exclude the
223 directory, but only directory
224 itself. Note that lines of
225 this type do not influence the
226 effect of <varname>r</varname>
227 or <varname>R</varname> lines.
228 Lines of this type accept
229 shell-style globs in place of
235 <term><varname>r</varname></term>
236 <listitem><para>Remove a file
237 or directory if it exists.
238 This may not be used to remove
239 non-empty directories, use
240 <varname>R</varname> for that.
241 Lines of this type accept
242 shell-style globs in place of
244 names.</para></listitem>
248 <term><varname>R</varname></term>
249 <listitem><para>Recursively
250 remove a path and all its
251 subdirectories (if it is a
252 directory). Lines of this type
253 accept shell-style globs in
255 names.</para></listitem>
259 <term><varname>z</varname></term>
260 <listitem><para>Restore
261 SELinux security context
262 and set ownership and access
263 mode of a file or directory if
264 it exists. Lines of this type
265 accept shell-style globs in
266 place of normal path names.
271 <term><varname>Z</varname></term>
272 <listitem><para>Recursively
273 restore SELinux security
275 ownership and access mode of a
277 subdirectories (if it is a
278 directory). Lines of this type
279 accept shell-style globs in
281 names.</para></listitem>
285 <para>If the exclamation mark is used, this
286 line is only safe of execute during boot, and
287 can break a running system. Lines without the
288 exclamation mark are presumed to be safe to
289 execute at any time, e.g. on package upgrades.
290 <command>systemd-tmpfiles</command> will
291 execute line with an exclamation mark only if
292 option <option>--boot</option> is given.
296 <programlisting># Make sure these are created by default so that nobody else can
297 d /tmp/.X11-unix 1777 root root 10d
299 # Unlink the X11 lock files
300 r! /tmp/.X[0-9]*-lock</programlisting>
301 The second line in contrast to the first one
302 would break a running system, and will only be
303 executed with <option>--boot</option>.</para>
309 <para>The file system path specification supports simple specifier
310 expansion. The following expansions are
314 <title>Specifiers available</title>
315 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
316 <colspec colname="spec" />
317 <colspec colname="mean" />
318 <colspec colname="detail" />
321 <entry>Specifier</entry>
322 <entry>Meaning</entry>
323 <entry>Details</entry>
328 <entry><literal>%m</literal></entry>
329 <entry>Machine ID</entry>
330 <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>
333 <entry><literal>%b</literal></entry>
334 <entry>Boot ID</entry>
335 <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
338 <entry><literal>%H</literal></entry>
339 <entry>Host name</entry>
340 <entry>The hostname of the running system.</entry>
343 <entry><literal>%v</literal></entry>
344 <entry>Kernel release</entry>
345 <entry>Identical to <command>uname -r</command> output.</entry>
348 <entry><literal>%%</literal></entry>
349 <entry>Escaped %</entry>
350 <entry>Single percent sign.</entry>
360 <para>The file access mode to use when
361 creating this file or directory. If omitted or
362 when set to -, the default is used: 0755 for
363 directories, 0644 for all other file objects.
364 For <varname>z</varname>, <varname>Z</varname>
365 lines, if omitted or when set to
366 <literal>-</literal>, the file access mode
367 will not be modified. This parameter is
368 ignored for <varname>x</varname>,
369 <varname>r</varname>, <varname>R</varname>,
370 <varname>L</varname> lines.</para>
374 <title>UID, GID</title>
376 <para>The user and group to use for this file
377 or directory. This may either be a numeric
378 user/group ID or a user or group name. If
379 omitted or when set to <literal>-</literal>,
380 the default 0 (root) is used. For
381 <varname>z</varname>, <varname>Z</varname>
382 lines, when omitted or when set to -, the file
383 ownership will not be modified. These
384 parameters are ignored for
385 <varname>x</varname>, <varname>r</varname>,
386 <varname>R</varname>, <varname>L</varname>
392 <para>The date field, when set, is used to
393 decide what files to delete when cleaning. If
394 a file or directory is older than the current
395 time minus the age field, it is deleted. The
396 field format is a series of integers each
397 followed by one of the following
398 postfixes for the respective time units:</para>
402 <term><varname>s</varname></term>
403 <term><varname>min</varname></term>
404 <term><varname>h</varname></term>
405 <term><varname>d</varname></term>
406 <term><varname>w</varname></term>
407 <term><varname>ms</varname></term>
408 <term><varname>m</varname></term>
409 <term><varname>us</varname></term></varlistentry>
412 <para>If multiple integers and units are specified, the time
413 values are summed up. If an integer is given without a unit,
417 <para>When the age is set to zero, the files are cleaned
418 unconditionally.</para>
420 <para>The age field only applies to lines
421 starting with <varname>d</varname>,
422 <varname>D</varname>, and
423 <varname>x</varname>. If omitted or set to
424 <literal>-</literal>, no automatic clean-up is
427 <para>If the age field starts with a tilde
428 character <literal>~</literal>, the clean-up
429 is only applied to files and directories one
430 level inside the directory specified, but not
431 the files and directories immediately inside
436 <title>Argument</title>
438 <para>For <varname>L</varname> lines
439 determines the destination path of the
440 symlink. For <varname>c</varname>,
441 <varname>b</varname> determines the
442 major/minor of the device node, with major and
443 minor formatted as integers, separated by
444 <literal>:</literal>, e.g.
445 <literal>1:3</literal>. For
446 <varname>f</varname>, <varname>F</varname>,
447 and <varname>w</varname> may be used to
448 specify a short string that is written to the
449 file, suffixed by a newline. Ignored for all
456 <title>Example</title>
458 <title>/etc/tmpfiles.d/screen.conf example</title>
459 <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
461 <programlisting>d /run/screens 1777 root root 10d
462 d /run/uscreens 0755 root root 10d12h</programlisting>
465 <title>/etc/tmpfiles.d/abrt.conf example</title>
466 <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
468 <programlisting>d /var/tmp/abrt 0755 abrt abrt
469 x /var/tmp/abrt/*</programlisting>
474 <title>See Also</title>
476 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
477 <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
478 <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
479 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>