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[elogind.git] / man / tmpfiles.d.xml
1 <?xml version="1.0"?>
2 <!--*-nxml-*-->
3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4 <!--
5   This file is part of systemd.
6
7   Copyright 2010 Brandon Philips
8
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.
13
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.
18
19   You should have received a copy of the GNU Lesser General Public License
20   along with systemd; If not, see <http://www.gnu.org/licenses/>.
21 -->
22 <refentry id="tmpfiles.d">
23
24         <refentryinfo>
25                 <title>tmpfiles.d</title>
26                 <productname>systemd</productname>
27
28                 <authorgroup>
29                         <author>
30                                 <contrib>Documentation</contrib>
31                                 <firstname>Brandon</firstname>
32                                 <surname>Philips</surname>
33                                 <email>brandon@ifup.org</email>
34                         </author>
35                 </authorgroup>
36         </refentryinfo>
37
38         <refmeta>
39                 <refentrytitle>tmpfiles.d</refentrytitle>
40                 <manvolnum>5</manvolnum>
41         </refmeta>
42
43         <refnamediv>
44                 <refname>tmpfiles.d</refname>
45                 <refpurpose>Configuration for creation, deletion and
46                 cleaning of volatile and temporary files</refpurpose>
47         </refnamediv>
48
49         <refsynopsisdiv>
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>
53         </refsynopsisdiv>
54
55         <refsect1>
56                 <title>Description</title>
57
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>
64
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>
73
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>
81         </refsect1>
82
83         <refsect1>
84                 <title>Configuration Format</title>
85
86                 <para>Each configuration file shall be named in the
87                 style of
88                 <filename><replaceable>package</replaceable>.conf</filename>
89                 or
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
93                 configuration.</para>
94
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.
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>
117
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>
124
125                 <para>The configuration format is one line per path
126                 containing type, path, mode, ownership, age, and argument
127                 fields:</para>
128
129                 <programlisting>#Type Path        Mode UID  GID  Age Argument
130 d    /run/user   0755 root root 10d -
131 L    /tmp/foobar -    -    -    -   /dev/null</programlisting>
132
133                 <refsect2>
134                         <title>Type</title>
135
136                         <para>The type consists of a single letter and
137                         optionally an exclamation mark.</para>
138
139                         <para>The following line types are understood:</para>
140
141                         <variablelist>
142                                 <varlistentry>
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>
145                                 </varlistentry>
146
147                                 <varlistentry>
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>
150                                 </varlistentry>
151
152                                 <varlistentry>
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>
158                                 </varlistentry>
159
160                                 <varlistentry>
161                                         <term><varname>d</varname></term>
162                                         <listitem><para>Create a directory if it does not exist yet.</para></listitem>
163                                 </varlistentry>
164
165                                 <varlistentry>
166                                         <term><varname>D</varname></term>
167                                         <listitem><para>Create or empty a directory.</para></listitem>
168                                 </varlistentry>
169
170                                 <varlistentry>
171                                         <term><varname>p</varname></term>
172                                         <term><varname>p+</varname></term>
173                                         <listitem><para>Create a named
174                                         pipe (FIFO) if it does not
175                                         exist yet. If suffixed with
176                                         <varname>+</varname> and a
177                                         file already exists where the
178                                         pipe is to be created, it will
179                                         be removed and be replaced by
180                                         the pipe.</para></listitem>
181                                 </varlistentry>
182
183                                 <varlistentry>
184                                         <term><varname>L</varname></term>
185                                         <term><varname>L+</varname></term>
186                                         <listitem><para>Create a
187                                         symlink if it does not exist
188                                         yet. If suffixed with
189                                         <varname>+</varname> and a
190                                         file already exists where the
191                                         symlink is to be created, it
192                                         will be removed and be
193                                         replaced by the
194                                         symlink. If the argument is omitted,
195                                         symlinks to files with the same name
196                                         residing in the directory
197                                         <filename>/usr/share/factory/</filename>
198                                         are created.</para></listitem>
199                                 </varlistentry>
200
201                                 <varlistentry>
202                                         <term><varname>c</varname></term>
203                                         <term><varname>c+</varname></term>
204                                         <listitem><para>Create a
205                                         character device node if it
206                                         does not exist yet. If
207                                         suffixed with
208                                         <varname>+</varname> and a
209                                         file already exists where the
210                                         device node is to be created,
211                                         it will be removed and be
212                                         replaced by the device
213                                         node. It is recommended to suffix this
214                                         entry with an exclamation mark to only
215                                         create static device nodes at boot,
216                                         as udev will not manage static device
217                                         nodes that are created at runtime.
218                                         </para></listitem>
219                                 </varlistentry>
220
221                                 <varlistentry>
222                                         <term><varname>b</varname></term>
223                                         <term><varname>b+</varname></term>
224                                         <listitem><para>Create a block
225                                         device node if it does not
226                                         exist yet. If suffixed with
227                                         <varname>+</varname> and a
228                                         file already exists where the
229                                         device node is to be created,
230                                         it will be removed and be
231                                         replaced by the device
232                                         node. It is recommended to suffix this
233                                         entry with an exclamation mark to only
234                                         create static device nodes at boot,
235                                         as udev will not manage static device
236                                         nodes that are created at runtime.
237                                         </para></listitem>
238                                 </varlistentry>
239
240                                 <varlistentry>
241                                         <term><varname>C</varname></term>
242                                         <listitem><para>Recursively
243                                         copy a file or directory, if
244                                         the destination files or
245                                         directories do not exist
246                                         yet. Note that this command
247                                         will not descend into
248                                         subdirectories if the
249                                         destination directory already
250                                         exists. Instead, the entire
251                                         copy operation is
252                                         skipped. If the argument is omitted,
253                                         files from the source directory
254                                         <filename>/usr/share/factory/</filename>
255                                         with the same name are copied.</para></listitem>
256                                 </varlistentry>
257
258                                 <varlistentry>
259                                         <term><varname>x</varname></term>
260                                         <listitem><para>Ignore a path
261                                         during cleaning. Use this type
262                                         to exclude paths from clean-up
263                                         as controlled with the Age
264                                         parameter. Note that lines of
265                                         this type do not influence the
266                                         effect of <varname>r</varname>
267                                         or <varname>R</varname> lines.
268                                         Lines of this type accept
269                                         shell-style globs in place of
270                                         normal path names.
271                                         </para></listitem>
272                                 </varlistentry>
273
274                                 <varlistentry>
275                                         <term><varname>X</varname></term>
276                                         <listitem><para>Ignore a path
277                                         during cleaning. Use this type
278                                         to exclude paths from clean-up
279                                         as controlled with the Age
280                                         parameter. Unlike
281                                         <varname>x</varname>, this
282                                         parameter will not exclude the
283                                         content if path is a
284                                         directory, but only directory
285                                         itself. Note that lines of
286                                         this type do not influence the
287                                         effect of <varname>r</varname>
288                                         or <varname>R</varname> lines.
289                                         Lines of this type accept
290                                         shell-style globs in place of
291                                         normal path names.
292                                         </para></listitem>
293                                 </varlistentry>
294
295                                 <varlistentry>
296                                         <term><varname>r</varname></term>
297                                         <listitem><para>Remove a file
298                                         or directory if it exists.
299                                         This may not be used to remove
300                                         non-empty directories, use
301                                         <varname>R</varname> for that.
302                                         Lines of this type accept
303                                         shell-style globs in place of
304                                         normal path
305                                         names.</para></listitem>
306                                 </varlistentry>
307
308                                 <varlistentry>
309                                         <term><varname>R</varname></term>
310                                         <listitem><para>Recursively
311                                         remove a path and all its
312                                         subdirectories (if it is a
313                                         directory). Lines of this type
314                                         accept shell-style globs in
315                                         place of normal path
316                                         names.</para></listitem>
317                                 </varlistentry>
318
319                                 <varlistentry>
320                                         <term><varname>z</varname></term>
321                                         <listitem><para>Adjust the
322                                         access mode, group and user,
323                                         and restore the SELinux security
324                                         context of a file or directory,
325                                         if it exists. Lines of this
326                                         type accept shell-style globs
327                                         in place of normal path names.
328                                         </para></listitem>
329                                 </varlistentry>
330
331                                 <varlistentry>
332                                         <term><varname>Z</varname></term>
333                                         <listitem><para>Recursively
334                                         set the access mode, group and
335                                         user, and restore the SELinux
336                                         security context of a file or
337                                         directory if it exists, as
338                                         well as of its subdirectories
339                                         and the files contained
340                                         therein (if applicable). Lines
341                                         of this type accept
342                                         shell-style globs in place of
343                                         normal path
344                                         names.</para></listitem>
345                                 </varlistentry>
346
347                                 <varlistentry>
348                                         <term><varname>t</varname></term>
349                                         <listitem><para>Set extended
350                                         attributes on item. It may be
351                                         used in conjunction with other
352                                         types (only <varname>d</varname>,
353                                         <varname>D</varname>, <varname>f</varname>,
354                                         <varname>F</varname>, <varname>L</varname>,
355                                         <varname>p</varname>, <varname>c</varname>,
356                                         <varname>b</varname>, makes sense).
357                                         If used as a standalone line, then
358                                         <command>systemd-tmpfiles</command>
359                                         will try to set extended
360                                         attributes on specified path.
361                                         This can be especially used to set
362                                         SMACK labels.
363                                         </para></listitem>
364                                 </varlistentry>
365                         </variablelist>
366
367                         <para>If the exclamation mark is used, this
368                         line is only safe of execute during boot, and
369                         can break a running system. Lines without the
370                         exclamation mark are presumed to be safe to
371                         execute at any time, e.g. on package upgrades.
372                         <command>systemd-tmpfiles</command> will
373                         execute line with an exclamation mark only if
374                         option <option>--boot</option> is given.
375                         </para>
376
377                         <para>For example:
378                         <programlisting># Make sure these are created by default so that nobody else can
379 d /tmp/.X11-unix 1777 root root 10d
380
381 # Unlink the X11 lock files
382 r! /tmp/.X[0-9]*-lock</programlisting>
383                         The second line in contrast to the first one
384                         would break a running system, and will only be
385                         executed with <option>--boot</option>.</para>
386                 </refsect2>
387
388                 <refsect2>
389                         <title>Path</title>
390
391                         <para>The file system path specification supports simple specifier
392                         expansion. The following expansions are
393                         understood:</para>
394
395                         <table>
396                                 <title>Specifiers available</title>
397                                 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
398                                         <colspec colname="spec" />
399                                         <colspec colname="mean" />
400                                         <colspec colname="detail" />
401                                         <thead>
402                                                 <row>
403                                                         <entry>Specifier</entry>
404                                                         <entry>Meaning</entry>
405                                                         <entry>Details</entry>
406                                                 </row>
407                                         </thead>
408                                         <tbody>
409                                                 <row>
410                                                         <entry><literal>%m</literal></entry>
411                                                         <entry>Machine ID</entry>
412                                                         <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>
413                                                 </row>
414                                                 <row>
415                                                         <entry><literal>%b</literal></entry>
416                                                         <entry>Boot ID</entry>
417                                                         <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
418                                                 </row>
419                                                 <row>
420                                                         <entry><literal>%H</literal></entry>
421                                                         <entry>Host name</entry>
422                                                         <entry>The hostname of the running system.</entry>
423                                                 </row>
424                                                 <row>
425                                                         <entry><literal>%v</literal></entry>
426                                                         <entry>Kernel release</entry>
427                                                         <entry>Identical to <command>uname -r</command> output.</entry>
428                                                 </row>
429                                                 <row>
430                                                         <entry><literal>%%</literal></entry>
431                                                         <entry>Escaped %</entry>
432                                                         <entry>Single percent sign.</entry>
433                                                 </row>
434                                         </tbody>
435                                 </tgroup>
436                         </table>
437                 </refsect2>
438
439                 <refsect2>
440                         <title>Mode</title>
441
442                         <para>The file access mode to use when
443                         creating this file or directory. If omitted or
444                         when set to -, the default is used: 0755 for
445                         directories, 0644 for all other file objects.
446                         For <varname>z</varname>, <varname>Z</varname>
447                         lines, if omitted or when set to
448                         <literal>-</literal>, the file access mode
449                         will not be modified. This parameter is
450                         ignored for <varname>x</varname>,
451                         <varname>r</varname>, <varname>R</varname>,
452                         <varname>L</varname>, <varname>t</varname> lines.</para>
453
454                         <para>Optionally, if prefixed with
455                         <literal>~</literal>, the access mode is masked
456                         based on the already set access bits for
457                         existing file or directories: if the existing
458                         file has all executable bits unset, all
459                         executable bits are removed from the new
460                         access mode, too. Similarly, if all read bits
461                         are removed from the old access mode, they will
462                         be removed from the new access mode too, and
463                         if all write bits are removed, they will be
464                         removed from the new access mode too. In
465                         addition, the sticky/SUID/SGID bit is removed unless
466                         applied to a directory. This
467                         functionality is particularly useful in
468                         conjunction with <varname>Z</varname>.</para>
469                 </refsect2>
470
471                 <refsect2>
472                         <title>UID, GID</title>
473
474                         <para>The user and group to use for this file
475                         or directory. This may either be a numeric
476                         user/group ID or a user or group name. If
477                         omitted or when set to <literal>-</literal>,
478                         the default 0 (root) is used. For
479                         <varname>z</varname>, <varname>Z</varname>
480                         lines, when omitted or when set to -, the file
481                         ownership will not be modified. These
482                         parameters are ignored for
483                         <varname>x</varname>, <varname>r</varname>,
484                         <varname>R</varname>, <varname>L</varname>,
485                         <varname>t</varname> lines.</para>
486                 </refsect2>
487
488                 <refsect2>
489                         <title>Age</title>
490                         <para>The date field, when set, is used to
491                         decide what files to delete when cleaning. If
492                         a file or directory is older than the current
493                         time minus the age field, it is deleted. The
494                         field format is a series of integers each
495                         followed by one of the following
496                         postfixes for the respective time units:</para>
497
498                         <variablelist>
499                                 <varlistentry>
500                                 <term><varname>s</varname></term>
501                                 <term><varname>min</varname></term>
502                                 <term><varname>h</varname></term>
503                                 <term><varname>d</varname></term>
504                                 <term><varname>w</varname></term>
505                                 <term><varname>ms</varname></term>
506                                 <term><varname>m</varname></term>
507                                 <term><varname>us</varname></term></varlistentry>
508                         </variablelist>
509
510                         <para>If multiple integers and units are specified, the time
511                         values are summed up. If an integer is given without a unit,
512                         s is assumed.
513                         </para>
514
515                         <para>When the age is set to zero, the files are cleaned
516                         unconditionally.</para>
517
518                         <para>The age field only applies to lines
519                         starting with <varname>d</varname>,
520                         <varname>D</varname>, and
521                         <varname>x</varname>. If omitted or set to
522                         <literal>-</literal>, no automatic clean-up is
523                         done.</para>
524
525                         <para>If the age field starts with a tilde
526                         character <literal>~</literal>, the clean-up
527                         is only applied to files and directories one
528                         level inside the directory specified, but not
529                         the files and directories immediately inside
530                         it.</para>
531                 </refsect2>
532
533                 <refsect2>
534                         <title>Argument</title>
535
536                         <para>For <varname>L</varname> lines
537                         determines the destination path of the
538                         symlink. For <varname>c</varname>,
539                         <varname>b</varname> determines the
540                         major/minor of the device node, with major and
541                         minor formatted as integers, separated by
542                         <literal>:</literal>, e.g.
543                         <literal>1:3</literal>. For
544                         <varname>f</varname>, <varname>F</varname>,
545                         and <varname>w</varname> may be used to
546                         specify a short string that is written to the
547                         file, suffixed by a newline. For
548                         <varname>C</varname>, specifies the source file
549                         or directory. For <varname>t</varname> determines
550                         extended attributes to be set. Ignored for all other lines.</para>
551                 </refsect2>
552
553         </refsect1>
554
555         <refsect1>
556                 <title>Example</title>
557                 <example>
558                         <title>/etc/tmpfiles.d/screen.conf example</title>
559                         <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
560
561                         <programlisting>d /run/screens  1777 root root 10d
562 d /run/uscreens 0755 root root 10d12h
563 t /run/screen - - - - user.name="John Smith" security.SMACK64=screen</programlisting>
564                 </example>
565                 <example>
566                         <title>/etc/tmpfiles.d/abrt.conf example</title>
567                         <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
568
569                         <programlisting>d /var/tmp/abrt 0755 abrt abrt
570 x /var/tmp/abrt/*</programlisting>
571                 </example>
572         </refsect1>
573
574         <refsect1>
575                 <title>See Also</title>
576                 <para>
577                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
578                         <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
579                         <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
580                         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
581                 </para>
582         </refsect1>
583
584 </refentry>