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>C</varname></term>
188 <listitem><para>Recursively copy a file or directory, if the destination files or directories don't exist yet.</para></listitem>
192 <term><varname>x</varname></term>
193 <listitem><para>Ignore a path
194 during cleaning. Use this type
195 to exclude paths from clean-up
196 as controlled with the Age
197 parameter. Note that lines of
198 this type do not influence the
199 effect of <varname>r</varname>
200 or <varname>R</varname> lines.
201 Lines of this type accept
202 shell-style globs in place of
208 <term><varname>X</varname></term>
209 <listitem><para>Ignore a path
210 during cleaning. Use this type
211 to exclude paths from clean-up
212 as controlled with the Age
214 <varname>x</varname>, this
215 parameter will not exclude the
217 directory, but only directory
218 itself. Note that lines of
219 this type do not influence the
220 effect of <varname>r</varname>
221 or <varname>R</varname> lines.
222 Lines of this type accept
223 shell-style globs in place of
229 <term><varname>r</varname></term>
230 <listitem><para>Remove a file
231 or directory if it exists.
232 This may not be used to remove
233 non-empty directories, use
234 <varname>R</varname> for that.
235 Lines of this type accept
236 shell-style globs in place of
238 names.</para></listitem>
242 <term><varname>R</varname></term>
243 <listitem><para>Recursively
244 remove a path and all its
245 subdirectories (if it is a
246 directory). Lines of this type
247 accept shell-style globs in
249 names.</para></listitem>
253 <term><varname>z</varname></term>
254 <listitem><para>Adjust the
255 access mode, group and user,
256 and restore the SELinux security
257 context of a file or directory,
258 if it exists. Lines of this
259 type accept shell-style globs
260 in place of normal path names.
265 <term><varname>Z</varname></term>
266 <listitem><para>Recursively
267 set the access mode, group and
268 user, and restore the SELinux
269 security context of a file or
270 directory if it exists, as
271 well as of its subdirectories
272 and the files contained
273 therein (if applicable). Lines
275 shell-style globs in place of
277 names.</para></listitem>
281 <para>If the exclamation mark is used, this
282 line is only safe of execute during boot, and
283 can break a running system. Lines without the
284 exclamation mark are presumed to be safe to
285 execute at any time, e.g. on package upgrades.
286 <command>systemd-tmpfiles</command> will
287 execute line with an exclamation mark only if
288 option <option>--boot</option> is given.
292 <programlisting># Make sure these are created by default so that nobody else can
293 d /tmp/.X11-unix 1777 root root 10d
295 # Unlink the X11 lock files
296 r! /tmp/.X[0-9]*-lock</programlisting>
297 The second line in contrast to the first one
298 would break a running system, and will only be
299 executed with <option>--boot</option>.</para>
305 <para>The file system path specification supports simple specifier
306 expansion. The following expansions are
310 <title>Specifiers available</title>
311 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
312 <colspec colname="spec" />
313 <colspec colname="mean" />
314 <colspec colname="detail" />
317 <entry>Specifier</entry>
318 <entry>Meaning</entry>
319 <entry>Details</entry>
324 <entry><literal>%m</literal></entry>
325 <entry>Machine ID</entry>
326 <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>
329 <entry><literal>%b</literal></entry>
330 <entry>Boot ID</entry>
331 <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
334 <entry><literal>%H</literal></entry>
335 <entry>Host name</entry>
336 <entry>The hostname of the running system.</entry>
339 <entry><literal>%v</literal></entry>
340 <entry>Kernel release</entry>
341 <entry>Identical to <command>uname -r</command> output.</entry>
344 <entry><literal>%%</literal></entry>
345 <entry>Escaped %</entry>
346 <entry>Single percent sign.</entry>
356 <para>The file access mode to use when
357 creating this file or directory. If omitted or
358 when set to -, the default is used: 0755 for
359 directories, 0644 for all other file objects.
360 For <varname>z</varname>, <varname>Z</varname>
361 lines, if omitted or when set to
362 <literal>-</literal>, the file access mode
363 will not be modified. This parameter is
364 ignored for <varname>x</varname>,
365 <varname>r</varname>, <varname>R</varname>,
366 <varname>L</varname> lines.</para>
370 <title>UID, GID</title>
372 <para>The user and group to use for this file
373 or directory. This may either be a numeric
374 user/group ID or a user or group name. If
375 omitted or when set to <literal>-</literal>,
376 the default 0 (root) is used. For
377 <varname>z</varname>, <varname>Z</varname>
378 lines, when omitted or when set to -, the file
379 ownership will not be modified. These
380 parameters are ignored for
381 <varname>x</varname>, <varname>r</varname>,
382 <varname>R</varname>, <varname>L</varname>
388 <para>The date field, when set, is used to
389 decide what files to delete when cleaning. If
390 a file or directory is older than the current
391 time minus the age field, it is deleted. The
392 field format is a series of integers each
393 followed by one of the following
394 postfixes for the respective time units:</para>
398 <term><varname>s</varname></term>
399 <term><varname>min</varname></term>
400 <term><varname>h</varname></term>
401 <term><varname>d</varname></term>
402 <term><varname>w</varname></term>
403 <term><varname>ms</varname></term>
404 <term><varname>m</varname></term>
405 <term><varname>us</varname></term></varlistentry>
408 <para>If multiple integers and units are specified, the time
409 values are summed up. If an integer is given without a unit,
413 <para>When the age is set to zero, the files are cleaned
414 unconditionally.</para>
416 <para>The age field only applies to lines
417 starting with <varname>d</varname>,
418 <varname>D</varname>, and
419 <varname>x</varname>. If omitted or set to
420 <literal>-</literal>, no automatic clean-up is
423 <para>If the age field starts with a tilde
424 character <literal>~</literal>, the clean-up
425 is only applied to files and directories one
426 level inside the directory specified, but not
427 the files and directories immediately inside
432 <title>Argument</title>
434 <para>For <varname>L</varname> lines
435 determines the destination path of the
436 symlink. For <varname>c</varname>,
437 <varname>b</varname> determines the
438 major/minor of the device node, with major and
439 minor formatted as integers, separated by
440 <literal>:</literal>, e.g.
441 <literal>1:3</literal>. For
442 <varname>f</varname>, <varname>F</varname>,
443 and <varname>w</varname> may be used to
444 specify a short string that is written to the
445 file, suffixed by a newline. For
446 <varname>C</varname> specifies the source file
447 or directory. Ignored for all other
454 <title>Example</title>
456 <title>/etc/tmpfiles.d/screen.conf example</title>
457 <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
459 <programlisting>d /run/screens 1777 root root 10d
460 d /run/uscreens 0755 root root 10d12h</programlisting>
463 <title>/etc/tmpfiles.d/abrt.conf example</title>
464 <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
466 <programlisting>d /var/tmp/abrt 0755 abrt abrt
467 x /var/tmp/abrt/*</programlisting>
472 <title>See Also</title>
474 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
475 <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
476 <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
477 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>