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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15 WITHOUT ANY WARRANTY; without even the implied warranty of
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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 <term><varname>L+</varname></term>
178 <listitem><para>Create a
179 symlink if it does not exist
180 yet. If suffixed with
181 <varname>+</varname> and a
182 file already exists where the
183 symlink is to be created it
184 will be removed and be
186 symlink.</para></listitem>
190 <term><varname>c</varname></term>
191 <listitem><para>Create a character device node if it does not exist yet.</para></listitem>
195 <term><varname>b</varname></term>
196 <listitem><para>Create a block device node if it does not exist yet.</para></listitem>
200 <term><varname>C</varname></term>
201 <listitem><para>Recursively copy a file or directory, if the destination files or directories don't exist yet.</para></listitem>
205 <term><varname>x</varname></term>
206 <listitem><para>Ignore a path
207 during cleaning. Use this type
208 to exclude paths from clean-up
209 as controlled with the Age
210 parameter. Note that lines of
211 this type do not influence the
212 effect of <varname>r</varname>
213 or <varname>R</varname> lines.
214 Lines of this type accept
215 shell-style globs in place of
221 <term><varname>X</varname></term>
222 <listitem><para>Ignore a path
223 during cleaning. Use this type
224 to exclude paths from clean-up
225 as controlled with the Age
227 <varname>x</varname>, this
228 parameter will not exclude the
230 directory, but only directory
231 itself. Note that lines of
232 this type do not influence the
233 effect of <varname>r</varname>
234 or <varname>R</varname> lines.
235 Lines of this type accept
236 shell-style globs in place of
242 <term><varname>r</varname></term>
243 <listitem><para>Remove a file
244 or directory if it exists.
245 This may not be used to remove
246 non-empty directories, use
247 <varname>R</varname> for that.
248 Lines of this type accept
249 shell-style globs in place of
251 names.</para></listitem>
255 <term><varname>R</varname></term>
256 <listitem><para>Recursively
257 remove a path and all its
258 subdirectories (if it is a
259 directory). Lines of this type
260 accept shell-style globs in
262 names.</para></listitem>
266 <term><varname>z</varname></term>
267 <listitem><para>Adjust the
268 access mode, group and user,
269 and restore the SELinux security
270 context of a file or directory,
271 if it exists. Lines of this
272 type accept shell-style globs
273 in place of normal path names.
278 <term><varname>Z</varname></term>
279 <listitem><para>Recursively
280 set the access mode, group and
281 user, and restore the SELinux
282 security context of a file or
283 directory if it exists, as
284 well as of its subdirectories
285 and the files contained
286 therein (if applicable). Lines
288 shell-style globs in place of
290 names.</para></listitem>
294 <para>If the exclamation mark is used, this
295 line is only safe of execute during boot, and
296 can break a running system. Lines without the
297 exclamation mark are presumed to be safe to
298 execute at any time, e.g. on package upgrades.
299 <command>systemd-tmpfiles</command> will
300 execute line with an exclamation mark only if
301 option <option>--boot</option> is given.
305 <programlisting># Make sure these are created by default so that nobody else can
306 d /tmp/.X11-unix 1777 root root 10d
308 # Unlink the X11 lock files
309 r! /tmp/.X[0-9]*-lock</programlisting>
310 The second line in contrast to the first one
311 would break a running system, and will only be
312 executed with <option>--boot</option>.</para>
318 <para>The file system path specification supports simple specifier
319 expansion. The following expansions are
323 <title>Specifiers available</title>
324 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
325 <colspec colname="spec" />
326 <colspec colname="mean" />
327 <colspec colname="detail" />
330 <entry>Specifier</entry>
331 <entry>Meaning</entry>
332 <entry>Details</entry>
337 <entry><literal>%m</literal></entry>
338 <entry>Machine ID</entry>
339 <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>
342 <entry><literal>%b</literal></entry>
343 <entry>Boot ID</entry>
344 <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
347 <entry><literal>%H</literal></entry>
348 <entry>Host name</entry>
349 <entry>The hostname of the running system.</entry>
352 <entry><literal>%v</literal></entry>
353 <entry>Kernel release</entry>
354 <entry>Identical to <command>uname -r</command> output.</entry>
357 <entry><literal>%%</literal></entry>
358 <entry>Escaped %</entry>
359 <entry>Single percent sign.</entry>
369 <para>The file access mode to use when
370 creating this file or directory. If omitted or
371 when set to -, the default is used: 0755 for
372 directories, 0644 for all other file objects.
373 For <varname>z</varname>, <varname>Z</varname>
374 lines, if omitted or when set to
375 <literal>-</literal>, the file access mode
376 will not be modified. This parameter is
377 ignored for <varname>x</varname>,
378 <varname>r</varname>, <varname>R</varname>,
379 <varname>L</varname> lines.</para>
381 <para>Optionally, if prefixed with
382 <literal>~</literal> the access mode is masked
383 based on the already set access bits for
384 existing file or directories: if the existing
385 file has all executable bits unset then all
386 executable bits are removed from the new
387 access mode, too. Similar, if all read bits
388 are removed from the old access mode they will
389 be removed from the new access mode too, and
390 if all write bits are removed, they will be
391 removed from the new access mode too. In
392 addition the sticky/suid/gid bit is removed unless
393 applied to a directory. This
394 functionality is particularly useful in
395 conjunction with <varname>Z</varname>.</para>
399 <title>UID, GID</title>
401 <para>The user and group to use for this file
402 or directory. This may either be a numeric
403 user/group ID or a user or group name. If
404 omitted or when set to <literal>-</literal>,
405 the default 0 (root) is used. For
406 <varname>z</varname>, <varname>Z</varname>
407 lines, when omitted or when set to -, the file
408 ownership will not be modified. These
409 parameters are ignored for
410 <varname>x</varname>, <varname>r</varname>,
411 <varname>R</varname>, <varname>L</varname>
417 <para>The date field, when set, is used to
418 decide what files to delete when cleaning. If
419 a file or directory is older than the current
420 time minus the age field, it is deleted. The
421 field format is a series of integers each
422 followed by one of the following
423 postfixes for the respective time units:</para>
427 <term><varname>s</varname></term>
428 <term><varname>min</varname></term>
429 <term><varname>h</varname></term>
430 <term><varname>d</varname></term>
431 <term><varname>w</varname></term>
432 <term><varname>ms</varname></term>
433 <term><varname>m</varname></term>
434 <term><varname>us</varname></term></varlistentry>
437 <para>If multiple integers and units are specified, the time
438 values are summed up. If an integer is given without a unit,
442 <para>When the age is set to zero, the files are cleaned
443 unconditionally.</para>
445 <para>The age field only applies to lines
446 starting with <varname>d</varname>,
447 <varname>D</varname>, and
448 <varname>x</varname>. If omitted or set to
449 <literal>-</literal>, no automatic clean-up is
452 <para>If the age field starts with a tilde
453 character <literal>~</literal>, the clean-up
454 is only applied to files and directories one
455 level inside the directory specified, but not
456 the files and directories immediately inside
461 <title>Argument</title>
463 <para>For <varname>L</varname> lines
464 determines the destination path of the
465 symlink. For <varname>c</varname>,
466 <varname>b</varname> determines the
467 major/minor of the device node, with major and
468 minor formatted as integers, separated by
469 <literal>:</literal>, e.g.
470 <literal>1:3</literal>. For
471 <varname>f</varname>, <varname>F</varname>,
472 and <varname>w</varname> may be used to
473 specify a short string that is written to the
474 file, suffixed by a newline. For
475 <varname>C</varname> specifies the source file
476 or directory. Ignored for all other
483 <title>Example</title>
485 <title>/etc/tmpfiles.d/screen.conf example</title>
486 <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
488 <programlisting>d /run/screens 1777 root root 10d
489 d /run/uscreens 0755 root root 10d12h</programlisting>
492 <title>/etc/tmpfiles.d/abrt.conf example</title>
493 <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
495 <programlisting>d /var/tmp/abrt 0755 abrt abrt
496 x /var/tmp/abrt/*</programlisting>
501 <title>See Also</title>
503 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
504 <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
505 <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
506 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>