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
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  17   Lesser General Public License for more details.
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  20   along with systemd; If not, see <http://www.gnu.org/licenses/>.
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  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, 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>
 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                                         <listitem><para>Create a named pipe (FIFO) if it does not exist yet.</para></listitem>
 173                                 </varlistentry>
 174
 175                                 <varlistentry>
 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
 185                                         replaced by the
 186                                         symlink.</para></listitem>
 187                                 </varlistentry>
 188
 189                                 <varlistentry>
 190                                         <term><varname>c</varname></term>
 191                                         <listitem><para>Create a character device node if it does not exist yet.</para></listitem>
 192                                 </varlistentry>
 193
 194                                 <varlistentry>
 195                                         <term><varname>b</varname></term>
 196                                         <listitem><para>Create a block device node if it does not exist yet.</para></listitem>
 197                                 </varlistentry>
 198
 199                                 <varlistentry>
 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>
 202                                 </varlistentry>
 203
 204                                 <varlistentry>
 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
 216                                         normal path names.
 217                                         </para></listitem>
 218                                 </varlistentry>
 219
 220                                 <varlistentry>
 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
 226                                         parameter. Unlike
 227                                         <varname>x</varname>, this
 228                                         parameter will not exclude the
 229                                         content if path is a
 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
 237                                         normal path names.
 238                                         </para></listitem>
 239                                 </varlistentry>
 240
 241                                 <varlistentry>
 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
 250                                         normal path
 251                                         names.</para></listitem>
 252                                 </varlistentry>
 253
 254                                 <varlistentry>
 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
 261                                         place of normal path
 262                                         names.</para></listitem>
 263                                 </varlistentry>
 264
 265                                 <varlistentry>
 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.
 274                                         </para></listitem>
 275                                 </varlistentry>
 276
 277                                 <varlistentry>
 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
 287                                         of this type accept
 288                                         shell-style globs in place of
 289                                         normal path
 290                                         names.</para></listitem>
 291                                 </varlistentry>
 292                         </variablelist>
 293
 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.
 302                         </para>
 303
 304                         <para>For example:
 305                         <programlisting># Make sure these are created by default so that nobody else can
 306 d /tmp/.X11-unix 1777 root root 10d
 307
 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>
 313                 </refsect2>
 314
 315                 <refsect2>
 316                         <title>Path</title>
 317
 318                         <para>The file system path specification supports simple specifier
 319                         expansion. The following expansions are
 320                         understood:</para>
 321
 322                         <table>
 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" />
 328                                         <thead>
 329                                                 <row>
 330                                                         <entry>Specifier</entry>
 331                                                         <entry>Meaning</entry>
 332                                                         <entry>Details</entry>
 333                                                 </row>
 334                                         </thead>
 335                                         <tbody>
 336                                                 <row>
 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>
 340                                                 </row>
 341                                                 <row>
 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>
 345                                                 </row>
 346                                                 <row>
 347                                                         <entry><literal>%H</literal></entry>
 348                                                         <entry>Host name</entry>
 349                                                         <entry>The hostname of the running system.</entry>
 350                                                 </row>
 351                                                 <row>
 352                                                         <entry><literal>%v</literal></entry>
 353                                                         <entry>Kernel release</entry>
 354                                                         <entry>Identical to <command>uname -r</command> output.</entry>
 355                                                 </row>
 356                                                 <row>
 357                                                         <entry><literal>%%</literal></entry>
 358                                                         <entry>Escaped %</entry>
 359                                                         <entry>Single percent sign.</entry>
 360                                                 </row>
 361                                         </tbody>
 362                                 </tgroup>
 363                         </table>
 364                 </refsect2>
 365
 366                 <refsect2>
 367                         <title>Mode</title>
 368
 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>
 380
 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>
 396                 </refsect2>
 397
 398                 <refsect2>
 399                         <title>UID, GID</title>
 400
 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>
 412                         lines.</para>
 413                 </refsect2>
 414
 415                 <refsect2>
 416                         <title>Age</title>
 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>
 424
 425                         <variablelist>
 426                                 <varlistentry>
 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>
 435                         </variablelist>
 436
 437                         <para>If multiple integers and units are specified, the time
 438                         values are summed up. If an integer is given without a unit,
 439                         s is assumed.
 440                         </para>
 441
 442                         <para>When the age is set to zero, the files are cleaned
 443                         unconditionally.</para>
 444
 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
 450                         done.</para>
 451
 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
 457                         it.</para>
 458                 </refsect2>
 459
 460                 <refsect2>
 461                         <title>Argument</title>
 462
 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
 477                         lines.</para>
 478                 </refsect2>
 479
 480         </refsect1>
 481
 482         <refsect1>
 483                 <title>Example</title>
 484                 <example>
 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>
 487
 488                         <programlisting>d /run/screens  1777 root root 10d
 489 d /run/uscreens 0755 root root 10d12h</programlisting>
 490                 </example>
 491                 <example>
 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>
 494
 495                         <programlisting>d /var/tmp/abrt 0755 abrt abrt
 496 x /var/tmp/abrt/*</programlisting>
 497                 </example>
 498         </refsect1>
 499
 500         <refsect1>
 501                 <title>See Also</title>
 502                 <para>
 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>
 507                 </para>
 508         </refsect1>
 509
 510 </refentry>