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, all
 112                 all other conflicting entries logged as errors.</para>
 113
 114                 <para>If the administrator wants to disable a
 115                 configuration file supplied by the vendor, the
 116                 recommended way is to place a symlink to
 117                 <filename>/dev/null</filename> in
 118                 <filename>/etc/tmpfiles.d/</filename> bearing the
 119                 same filename.</para>
 120
 121                 <para>The configuration format is one line per path
 122                 containing type, path, mode, ownership, age, and argument
 123                 fields:</para>
 124
 125                 <programlisting>#Type Path        Mode UID  GID  Age Argument
 126 d    /run/user   0755 root root 10d -
 127 L    /tmp/foobar -    -    -    -   /dev/null</programlisting>
 128
 129                 <refsect2>
 130                         <title>Type</title>
 131
 132                         <para>The type consists of a single letter and
 133                         optionally an exclamation mark.</para>
 134
 135                         <para>The following line types are understood:</para>
 136
 137                         <variablelist>
 138                                 <varlistentry>
 139                                         <term><varname>f</varname></term>
 140                                         <listitem><para>Create a file if it does not exist yet. If the argument parameter is given, it will be written to the file.</para></listitem>
 141                                 </varlistentry>
 142
 143                                 <varlistentry>
 144                                         <term><varname>F</varname></term>
 145                                         <listitem><para>Create or truncate a file. If the argument parameter is given, it will be written to the file.</para></listitem>
 146                                 </varlistentry>
 147
 148                                 <varlistentry>
 149                                         <term><varname>w</varname></term>
 150                                         <listitem><para>Write the argument parameter to a file, if the file exists.
 151                                             Lines of this type accept shell-style globs in place of normal path
 152                                             names. The argument parameter will be written without a trailing
 153                                             newline. C-style backslash escapes are interpreted.</para></listitem>
 154                                 </varlistentry>
 155
 156                                 <varlistentry>
 157                                         <term><varname>d</varname></term>
 158                                         <listitem><para>Create a directory if it does not exist yet.</para></listitem>
 159                                 </varlistentry>
 160
 161                                 <varlistentry>
 162                                         <term><varname>D</varname></term>
 163                                         <listitem><para>Create or empty a directory.</para></listitem>
 164                                 </varlistentry>
 165
 166                                 <varlistentry>
 167                                         <term><varname>p</varname></term>
 168                                         <listitem><para>Create a named pipe (FIFO) if it does not exist yet.</para></listitem>
 169                                 </varlistentry>
 170
 171                                 <varlistentry>
 172                                         <term><varname>L</varname></term>
 173                                         <listitem><para>Create a symlink if it does not exist yet.</para></listitem>
 174                                 </varlistentry>
 175
 176                                 <varlistentry>
 177                                         <term><varname>c</varname></term>
 178                                         <listitem><para>Create a character device node if it does not exist yet.</para></listitem>
 179                                 </varlistentry>
 180
 181                                 <varlistentry>
 182                                         <term><varname>b</varname></term>
 183                                         <listitem><para>Create a block device node if it does not exist yet.</para></listitem>
 184                                 </varlistentry>
 185
 186                                 <varlistentry>
 187                                         <term><varname>C</varname></term>
 188                                         <listitem><para>Recursively copy a file or directory, if the destination files or directories don't exist yet.</para></listitem>
 189                                 </varlistentry>
 190
 191                                 <varlistentry>
 192                                         <term><varname>x</varname></term>
 193                                         <listitem><para>Ignore a path
 194                                         during cleaning. Use this type
 195                                         to exclude paths from clean-up
 196                                         as controlled with the Age
 197                                         parameter. Note that lines of
 198                                         this type do not influence the
 199                                         effect of <varname>r</varname>
 200                                         or <varname>R</varname> lines.
 201                                         Lines of this type accept
 202                                         shell-style globs in place of
 203                                         normal path names.
 204                                         </para></listitem>
 205                                 </varlistentry>
 206
 207                                 <varlistentry>
 208                                         <term><varname>X</varname></term>
 209                                         <listitem><para>Ignore a path
 210                                         during cleaning. Use this type
 211                                         to exclude paths from clean-up
 212                                         as controlled with the Age
 213                                         parameter. Unlike
 214                                         <varname>x</varname>, this
 215                                         parameter will not exclude the
 216                                         content if path is a
 217                                         directory, but only directory
 218                                         itself. Note that lines of
 219                                         this type do not influence the
 220                                         effect of <varname>r</varname>
 221                                         or <varname>R</varname> lines.
 222                                         Lines of this type accept
 223                                         shell-style globs in place of
 224                                         normal path names.
 225                                         </para></listitem>
 226                                 </varlistentry>
 227
 228                                 <varlistentry>
 229                                         <term><varname>r</varname></term>
 230                                         <listitem><para>Remove a file
 231                                         or directory if it exists.
 232                                         This may not be used to remove
 233                                         non-empty directories, use
 234                                         <varname>R</varname> for that.
 235                                         Lines of this type accept
 236                                         shell-style globs in place of
 237                                         normal path
 238                                         names.</para></listitem>
 239                                 </varlistentry>
 240
 241                                 <varlistentry>
 242                                         <term><varname>R</varname></term>
 243                                         <listitem><para>Recursively
 244                                         remove a path and all its
 245                                         subdirectories (if it is a
 246                                         directory). Lines of this type
 247                                         accept shell-style globs in
 248                                         place of normal path
 249                                         names.</para></listitem>
 250                                 </varlistentry>
 251
 252                                 <varlistentry>
 253                                         <term><varname>z</varname></term>
 254                                         <listitem><para>Adjust the
 255                                         access mode, group and user,
 256                                         and restore the SELinux security
 257                                         context of a file or directory,
 258                                         if it exists. Lines of this
 259                                         type accept shell-style globs
 260                                         in place of normal path names.
 261                                         </para></listitem>
 262                                 </varlistentry>
 263
 264                                 <varlistentry>
 265                                         <term><varname>Z</varname></term>
 266                                         <listitem><para>Recursively
 267                                         set the access mode, group and
 268                                         user, and restore the SELinux
 269                                         security context of a file or
 270                                         directory if it exists, as
 271                                         well as of its subdirectories
 272                                         and the files contained
 273                                         therein (if applicable). Lines
 274                                         of this type accept
 275                                         shell-style globs in place of
 276                                         normal path
 277                                         names.</para></listitem>
 278                                 </varlistentry>
 279                         </variablelist>
 280
 281                         <para>If the exclamation mark is used, this
 282                         line is only safe of execute during boot, and
 283                         can break a running system. Lines without the
 284                         exclamation mark are presumed to be safe to
 285                         execute at any time, e.g. on package upgrades.
 286                         <command>systemd-tmpfiles</command> will
 287                         execute line with an exclamation mark only if
 288                         option <option>--boot</option> is given.
 289                         </para>
 290
 291                         <para>For example:
 292                         <programlisting># Make sure these are created by default so that nobody else can
 293 d /tmp/.X11-unix 1777 root root 10d
 294
 295 # Unlink the X11 lock files
 296 r! /tmp/.X[0-9]*-lock</programlisting>
 297                         The second line in contrast to the first one
 298                         would break a running system, and will only be
 299                         executed with <option>--boot</option>.</para>
 300                 </refsect2>
 301
 302                 <refsect2>
 303                         <title>Path</title>
 304
 305                         <para>The file system path specification supports simple specifier
 306                         expansion. The following expansions are
 307                         understood:</para>
 308
 309                         <table>
 310                                 <title>Specifiers available</title>
 311                                 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
 312                                         <colspec colname="spec" />
 313                                         <colspec colname="mean" />
 314                                         <colspec colname="detail" />
 315                                         <thead>
 316                                                 <row>
 317                                                         <entry>Specifier</entry>
 318                                                         <entry>Meaning</entry>
 319                                                         <entry>Details</entry>
 320                                                 </row>
 321                                         </thead>
 322                                         <tbody>
 323                                                 <row>
 324                                                         <entry><literal>%m</literal></entry>
 325                                                         <entry>Machine ID</entry>
 326                                                         <entry>The machine ID of the running system, formatted as string. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</entry>
 327                                                 </row>
 328                                                 <row>
 329                                                         <entry><literal>%b</literal></entry>
 330                                                         <entry>Boot ID</entry>
 331                                                         <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
 332                                                 </row>
 333                                                 <row>
 334                                                         <entry><literal>%H</literal></entry>
 335                                                         <entry>Host name</entry>
 336                                                         <entry>The hostname of the running system.</entry>
 337                                                 </row>
 338                                                 <row>
 339                                                         <entry><literal>%v</literal></entry>
 340                                                         <entry>Kernel release</entry>
 341                                                         <entry>Identical to <command>uname -r</command> output.</entry>
 342                                                 </row>
 343                                                 <row>
 344                                                         <entry><literal>%%</literal></entry>
 345                                                         <entry>Escaped %</entry>
 346                                                         <entry>Single percent sign.</entry>
 347                                                 </row>
 348                                         </tbody>
 349                                 </tgroup>
 350                         </table>
 351                 </refsect2>
 352
 353                 <refsect2>
 354                         <title>Mode</title>
 355
 356                         <para>The file access mode to use when
 357                         creating this file or directory. If omitted or
 358                         when set to -, the default is used: 0755 for
 359                         directories, 0644 for all other file objects.
 360                         For <varname>z</varname>, <varname>Z</varname>
 361                         lines, if omitted or when set to
 362                         <literal>-</literal>, the file access mode
 363                         will not be modified. This parameter is
 364                         ignored for <varname>x</varname>,
 365                         <varname>r</varname>, <varname>R</varname>,
 366                         <varname>L</varname> lines.</para>
 367                 </refsect2>
 368
 369                 <refsect2>
 370                         <title>UID, GID</title>
 371
 372                         <para>The user and group to use for this file
 373                         or directory. This may either be a numeric
 374                         user/group ID or a user or group name. If
 375                         omitted or when set to <literal>-</literal>,
 376                         the default 0 (root) is used. For
 377                         <varname>z</varname>, <varname>Z</varname>
 378                         lines, when omitted or when set to -, the file
 379                         ownership will not be modified. These
 380                         parameters are ignored for
 381                         <varname>x</varname>, <varname>r</varname>,
 382                         <varname>R</varname>, <varname>L</varname>
 383                         lines.</para>
 384                 </refsect2>
 385
 386                 <refsect2>
 387                         <title>Age</title>
 388                         <para>The date field, when set, is used to
 389                         decide what files to delete when cleaning. If
 390                         a file or directory is older than the current
 391                         time minus the age field, it is deleted. The
 392                         field format is a series of integers each
 393                         followed by one of the following
 394                         postfixes for the respective time units:</para>
 395
 396                         <variablelist>
 397                                 <varlistentry>
 398                                 <term><varname>s</varname></term>
 399                                 <term><varname>min</varname></term>
 400                                 <term><varname>h</varname></term>
 401                                 <term><varname>d</varname></term>
 402                                 <term><varname>w</varname></term>
 403                                 <term><varname>ms</varname></term>
 404                                 <term><varname>m</varname></term>
 405                                 <term><varname>us</varname></term></varlistentry>
 406                         </variablelist>
 407
 408                         <para>If multiple integers and units are specified, the time
 409                         values are summed up. If an integer is given without a unit,
 410                         s is assumed.
 411                         </para>
 412
 413                         <para>When the age is set to zero, the files are cleaned
 414                         unconditionally.</para>
 415
 416                         <para>The age field only applies to lines
 417                         starting with <varname>d</varname>,
 418                         <varname>D</varname>, and
 419                         <varname>x</varname>. If omitted or set to
 420                         <literal>-</literal>, no automatic clean-up is
 421                         done.</para>
 422
 423                         <para>If the age field starts with a tilde
 424                         character <literal>~</literal>, the clean-up
 425                         is only applied to files and directories one
 426                         level inside the directory specified, but not
 427                         the files and directories immediately inside
 428                         it.</para>
 429                 </refsect2>
 430
 431                 <refsect2>
 432                         <title>Argument</title>
 433
 434                         <para>For <varname>L</varname> lines
 435                         determines the destination path of the
 436                         symlink. For <varname>c</varname>,
 437                         <varname>b</varname> determines the
 438                         major/minor of the device node, with major and
 439                         minor formatted as integers, separated by
 440                         <literal>:</literal>, e.g.
 441                         <literal>1:3</literal>. For
 442                         <varname>f</varname>, <varname>F</varname>,
 443                         and <varname>w</varname> may be used to
 444                         specify a short string that is written to the
 445                         file, suffixed by a newline. For
 446                         <varname>C</varname> specifies the source file
 447                         or directory. Ignored for all other
 448                         lines.</para>
 449                 </refsect2>
 450
 451         </refsect1>
 452
 453         <refsect1>
 454                 <title>Example</title>
 455                 <example>
 456                         <title>/etc/tmpfiles.d/screen.conf example</title>
 457                         <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
 458
 459                         <programlisting>d /run/screens  1777 root root 10d
 460 d /run/uscreens 0755 root root 10d12h</programlisting>
 461                 </example>
 462                 <example>
 463                         <title>/etc/tmpfiles.d/abrt.conf example</title>
 464                         <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
 465
 466                         <programlisting>d /var/tmp/abrt 0755 abrt abrt
 467 x /var/tmp/abrt/*</programlisting>
 468                 </example>
 469         </refsect1>
 470
 471         <refsect1>
 472                 <title>See Also</title>
 473                 <para>
 474                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 475                         <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 476                         <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 477                         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 478                 </para>
 479         </refsect1>
 480
 481 </refentry>