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 will be logged as
113 errors. When two lines are prefix and suffix of each
114 other, then the prefix is always processed first, the
115 suffix later. Otherwise the files/directories are
116 processed in the order they are listed.</para>
118 <para>If the administrator wants to disable a
119 configuration file supplied by the vendor, the
120 recommended way is to place a symlink to
121 <filename>/dev/null</filename> in
122 <filename>/etc/tmpfiles.d/</filename> bearing the
123 same filename.</para>
125 <para>The configuration format is one line per path
126 containing type, path, mode, ownership, age, and argument
129 <programlisting>#Type Path Mode UID GID Age Argument
130 d /run/user 0755 root root 10d -
131 L /tmp/foobar - - - - /dev/null</programlisting>
136 <para>The type consists of a single letter and
137 optionally an exclamation mark.</para>
139 <para>The following line types are understood:</para>
143 <term><varname>f</varname></term>
144 <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>
148 <term><varname>F</varname></term>
149 <listitem><para>Create or truncate a file. If the argument parameter is given, it will be written to the file.</para></listitem>
153 <term><varname>w</varname></term>
154 <listitem><para>Write the argument parameter to a file, if the file exists.
155 Lines of this type accept shell-style globs in place of normal path
156 names. The argument parameter will be written without a trailing
157 newline. C-style backslash escapes are interpreted.</para></listitem>
161 <term><varname>d</varname></term>
162 <listitem><para>Create a directory if it does not exist yet.</para></listitem>
166 <term><varname>D</varname></term>
167 <listitem><para>Create or empty a directory.</para></listitem>
171 <term><varname>p</varname></term>
172 <listitem><para>Create a named pipe (FIFO) if it does not exist yet.</para></listitem>
176 <term><varname>L</varname></term>
177 <listitem><para>Create a symlink if it does not exist yet.</para></listitem>
181 <term><varname>c</varname></term>
182 <listitem><para>Create a character device node if it does not exist yet.</para></listitem>
186 <term><varname>b</varname></term>
187 <listitem><para>Create a block device node if it does not exist yet.</para></listitem>
191 <term><varname>C</varname></term>
192 <listitem><para>Recursively copy a file or directory, if the destination files or directories don't exist yet.</para></listitem>
196 <term><varname>x</varname></term>
197 <listitem><para>Ignore a path
198 during cleaning. Use this type
199 to exclude paths from clean-up
200 as controlled with the Age
201 parameter. Note that lines of
202 this type do not influence the
203 effect of <varname>r</varname>
204 or <varname>R</varname> lines.
205 Lines of this type accept
206 shell-style globs in place of
212 <term><varname>X</varname></term>
213 <listitem><para>Ignore a path
214 during cleaning. Use this type
215 to exclude paths from clean-up
216 as controlled with the Age
218 <varname>x</varname>, this
219 parameter will not exclude the
221 directory, but only directory
222 itself. Note that lines of
223 this type do not influence the
224 effect of <varname>r</varname>
225 or <varname>R</varname> lines.
226 Lines of this type accept
227 shell-style globs in place of
233 <term><varname>r</varname></term>
234 <listitem><para>Remove a file
235 or directory if it exists.
236 This may not be used to remove
237 non-empty directories, use
238 <varname>R</varname> for that.
239 Lines of this type accept
240 shell-style globs in place of
242 names.</para></listitem>
246 <term><varname>R</varname></term>
247 <listitem><para>Recursively
248 remove a path and all its
249 subdirectories (if it is a
250 directory). Lines of this type
251 accept shell-style globs in
253 names.</para></listitem>
257 <term><varname>z</varname></term>
258 <listitem><para>Adjust the
259 access mode, group and user,
260 and restore the SELinux security
261 context of a file or directory,
262 if it exists. Lines of this
263 type accept shell-style globs
264 in place of normal path names.
269 <term><varname>Z</varname></term>
270 <listitem><para>Recursively
271 set the access mode, group and
272 user, and restore the SELinux
273 security context of a file or
274 directory if it exists, as
275 well as of its subdirectories
276 and the files contained
277 therein (if applicable). Lines
279 shell-style globs in place of
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>
372 <para>Optionally, if prefixed with
373 <literal>~</literal> the access mode is masked
374 based on the already set access bits for
375 existing file or directories: if the existing
376 file has all executable bits unset then all
377 executable bits are removed from the new
378 access mode, too. Similar, if all read bits
379 are removed from the old access mode they will
380 be removed from the new access mode too, and
381 if all write bits are removed, they will be
382 removed from the new access mode too. In
383 addition the sticky/suid/gid bit is removed unless
384 applied to a directory. This
385 functionality is particularly useful in
386 conjunction with <varname>Z</varname>.</para>
390 <title>UID, GID</title>
392 <para>The user and group to use for this file
393 or directory. This may either be a numeric
394 user/group ID or a user or group name. If
395 omitted or when set to <literal>-</literal>,
396 the default 0 (root) is used. For
397 <varname>z</varname>, <varname>Z</varname>
398 lines, when omitted or when set to -, the file
399 ownership will not be modified. These
400 parameters are ignored for
401 <varname>x</varname>, <varname>r</varname>,
402 <varname>R</varname>, <varname>L</varname>
408 <para>The date field, when set, is used to
409 decide what files to delete when cleaning. If
410 a file or directory is older than the current
411 time minus the age field, it is deleted. The
412 field format is a series of integers each
413 followed by one of the following
414 postfixes for the respective time units:</para>
418 <term><varname>s</varname></term>
419 <term><varname>min</varname></term>
420 <term><varname>h</varname></term>
421 <term><varname>d</varname></term>
422 <term><varname>w</varname></term>
423 <term><varname>ms</varname></term>
424 <term><varname>m</varname></term>
425 <term><varname>us</varname></term></varlistentry>
428 <para>If multiple integers and units are specified, the time
429 values are summed up. If an integer is given without a unit,
433 <para>When the age is set to zero, the files are cleaned
434 unconditionally.</para>
436 <para>The age field only applies to lines
437 starting with <varname>d</varname>,
438 <varname>D</varname>, and
439 <varname>x</varname>. If omitted or set to
440 <literal>-</literal>, no automatic clean-up is
443 <para>If the age field starts with a tilde
444 character <literal>~</literal>, the clean-up
445 is only applied to files and directories one
446 level inside the directory specified, but not
447 the files and directories immediately inside
452 <title>Argument</title>
454 <para>For <varname>L</varname> lines
455 determines the destination path of the
456 symlink. For <varname>c</varname>,
457 <varname>b</varname> determines the
458 major/minor of the device node, with major and
459 minor formatted as integers, separated by
460 <literal>:</literal>, e.g.
461 <literal>1:3</literal>. For
462 <varname>f</varname>, <varname>F</varname>,
463 and <varname>w</varname> may be used to
464 specify a short string that is written to the
465 file, suffixed by a newline. For
466 <varname>C</varname> specifies the source file
467 or directory. Ignored for all other
474 <title>Example</title>
476 <title>/etc/tmpfiles.d/screen.conf example</title>
477 <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
479 <programlisting>d /run/screens 1777 root root 10d
480 d /run/uscreens 0755 root root 10d12h</programlisting>
483 <title>/etc/tmpfiles.d/abrt.conf example</title>
484 <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
486 <programlisting>d /var/tmp/abrt 0755 abrt abrt
487 x /var/tmp/abrt/*</programlisting>
492 <title>See Also</title>
494 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
495 <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
496 <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
497 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>