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 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.</para></listitem>
 195                                 </varlistentry>
 196
 197                                 <varlistentry>
 198                                         <term><varname>c</varname></term>
 199                                         <term><varname>c+</varname></term>
 200                                         <listitem><para>Create a
 201                                         character device node if it
 202                                         does not exist yet. If
 203                                         suffixed with
 204                                         <varname>+</varname> and a
 205                                         file already exists where the
 206                                         device node is to be created
 207                                         it will be removed and be
 208                                         replaced by the device
 209                                         node.</para></listitem>
 210                                 </varlistentry>
 211
 212                                 <varlistentry>
 213                                         <term><varname>b</varname></term>
 214                                         <term><varname>b+</varname></term>
 215                                         <listitem><para>Create a block
 216                                         device node if it does not
 217                                         exist yet. If suffixed with
 218                                         <varname>+</varname> and a
 219                                         file already exists where the
 220                                         device node is to be created
 221                                         it will be removed and be
 222                                         replaced by the device
 223                                         node.</para></listitem>
 224                                 </varlistentry>
 225
 226                                 <varlistentry>
 227                                         <term><varname>C</varname></term>
 228                                         <listitem><para>Recursively
 229                                         copy a file or directory, if
 230                                         the destination files or
 231                                         directories don't exist
 232                                         yet. Note that this command
 233                                         will not descend into
 234                                         subdirectories if the
 235                                         destination directory already
 236                                         exists, instead the entire
 237                                         copy operation is
 238                                         skipped.</para></listitem>
 239                                 </varlistentry>
 240
 241                                 <varlistentry>
 242                                         <term><varname>x</varname></term>
 243                                         <listitem><para>Ignore a path
 244                                         during cleaning. Use this type
 245                                         to exclude paths from clean-up
 246                                         as controlled with the Age
 247                                         parameter. Note that lines of
 248                                         this type do not influence the
 249                                         effect of <varname>r</varname>
 250                                         or <varname>R</varname> lines.
 251                                         Lines of this type accept
 252                                         shell-style globs in place of
 253                                         normal path names.
 254                                         </para></listitem>
 255                                 </varlistentry>
 256
 257                                 <varlistentry>
 258                                         <term><varname>X</varname></term>
 259                                         <listitem><para>Ignore a path
 260                                         during cleaning. Use this type
 261                                         to exclude paths from clean-up
 262                                         as controlled with the Age
 263                                         parameter. Unlike
 264                                         <varname>x</varname>, this
 265                                         parameter will not exclude the
 266                                         content if path is a
 267                                         directory, but only directory
 268                                         itself. Note that lines of
 269                                         this type do not influence the
 270                                         effect of <varname>r</varname>
 271                                         or <varname>R</varname> lines.
 272                                         Lines of this type accept
 273                                         shell-style globs in place of
 274                                         normal path names.
 275                                         </para></listitem>
 276                                 </varlistentry>
 277
 278                                 <varlistentry>
 279                                         <term><varname>r</varname></term>
 280                                         <listitem><para>Remove a file
 281                                         or directory if it exists.
 282                                         This may not be used to remove
 283                                         non-empty directories, use
 284                                         <varname>R</varname> for that.
 285                                         Lines of this type accept
 286                                         shell-style globs in place of
 287                                         normal path
 288                                         names.</para></listitem>
 289                                 </varlistentry>
 290
 291                                 <varlistentry>
 292                                         <term><varname>R</varname></term>
 293                                         <listitem><para>Recursively
 294                                         remove a path and all its
 295                                         subdirectories (if it is a
 296                                         directory). Lines of this type
 297                                         accept shell-style globs in
 298                                         place of normal path
 299                                         names.</para></listitem>
 300                                 </varlistentry>
 301
 302                                 <varlistentry>
 303                                         <term><varname>z</varname></term>
 304                                         <listitem><para>Adjust the
 305                                         access mode, group and user,
 306                                         and restore the SELinux security
 307                                         context of a file or directory,
 308                                         if it exists. Lines of this
 309                                         type accept shell-style globs
 310                                         in place of normal path names.
 311                                         </para></listitem>
 312                                 </varlistentry>
 313
 314                                 <varlistentry>
 315                                         <term><varname>Z</varname></term>
 316                                         <listitem><para>Recursively
 317                                         set the access mode, group and
 318                                         user, and restore the SELinux
 319                                         security context of a file or
 320                                         directory if it exists, as
 321                                         well as of its subdirectories
 322                                         and the files contained
 323                                         therein (if applicable). Lines
 324                                         of this type accept
 325                                         shell-style globs in place of
 326                                         normal path
 327                                         names.</para></listitem>
 328                                 </varlistentry>
 329                         </variablelist>
 330
 331                         <para>If the exclamation mark is used, this
 332                         line is only safe of execute during boot, and
 333                         can break a running system. Lines without the
 334                         exclamation mark are presumed to be safe to
 335                         execute at any time, e.g. on package upgrades.
 336                         <command>systemd-tmpfiles</command> will
 337                         execute line with an exclamation mark only if
 338                         option <option>--boot</option> is given.
 339                         </para>
 340
 341                         <para>For example:
 342                         <programlisting># Make sure these are created by default so that nobody else can
 343 d /tmp/.X11-unix 1777 root root 10d
 344
 345 # Unlink the X11 lock files
 346 r! /tmp/.X[0-9]*-lock</programlisting>
 347                         The second line in contrast to the first one
 348                         would break a running system, and will only be
 349                         executed with <option>--boot</option>.</para>
 350                 </refsect2>
 351
 352                 <refsect2>
 353                         <title>Path</title>
 354
 355                         <para>The file system path specification supports simple specifier
 356                         expansion. The following expansions are
 357                         understood:</para>
 358
 359                         <table>
 360                                 <title>Specifiers available</title>
 361                                 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
 362                                         <colspec colname="spec" />
 363                                         <colspec colname="mean" />
 364                                         <colspec colname="detail" />
 365                                         <thead>
 366                                                 <row>
 367                                                         <entry>Specifier</entry>
 368                                                         <entry>Meaning</entry>
 369                                                         <entry>Details</entry>
 370                                                 </row>
 371                                         </thead>
 372                                         <tbody>
 373                                                 <row>
 374                                                         <entry><literal>%m</literal></entry>
 375                                                         <entry>Machine ID</entry>
 376                                                         <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>
 377                                                 </row>
 378                                                 <row>
 379                                                         <entry><literal>%b</literal></entry>
 380                                                         <entry>Boot ID</entry>
 381                                                         <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
 382                                                 </row>
 383                                                 <row>
 384                                                         <entry><literal>%H</literal></entry>
 385                                                         <entry>Host name</entry>
 386                                                         <entry>The hostname of the running system.</entry>
 387                                                 </row>
 388                                                 <row>
 389                                                         <entry><literal>%v</literal></entry>
 390                                                         <entry>Kernel release</entry>
 391                                                         <entry>Identical to <command>uname -r</command> output.</entry>
 392                                                 </row>
 393                                                 <row>
 394                                                         <entry><literal>%%</literal></entry>
 395                                                         <entry>Escaped %</entry>
 396                                                         <entry>Single percent sign.</entry>
 397                                                 </row>
 398                                         </tbody>
 399                                 </tgroup>
 400                         </table>
 401                 </refsect2>
 402
 403                 <refsect2>
 404                         <title>Mode</title>
 405
 406                         <para>The file access mode to use when
 407                         creating this file or directory. If omitted or
 408                         when set to -, the default is used: 0755 for
 409                         directories, 0644 for all other file objects.
 410                         For <varname>z</varname>, <varname>Z</varname>
 411                         lines, if omitted or when set to
 412                         <literal>-</literal>, the file access mode
 413                         will not be modified. This parameter is
 414                         ignored for <varname>x</varname>,
 415                         <varname>r</varname>, <varname>R</varname>,
 416                         <varname>L</varname> lines.</para>
 417
 418                         <para>Optionally, if prefixed with
 419                         <literal>~</literal> the access mode is masked
 420                         based on the already set access bits for
 421                         existing file or directories: if the existing
 422                         file has all executable bits unset then all
 423                         executable bits are removed from the new
 424                         access mode, too. Similar, if all read bits
 425                         are removed from the old access mode they will
 426                         be removed from the new access mode too, and
 427                         if all write bits are removed, they will be
 428                         removed from the new access mode too. In
 429                         addition the sticky/suid/gid bit is removed unless
 430                         applied to a directory. This
 431                         functionality is particularly useful in
 432                         conjunction with <varname>Z</varname>.</para>
 433                 </refsect2>
 434
 435                 <refsect2>
 436                         <title>UID, GID</title>
 437
 438                         <para>The user and group to use for this file
 439                         or directory. This may either be a numeric
 440                         user/group ID or a user or group name. If
 441                         omitted or when set to <literal>-</literal>,
 442                         the default 0 (root) is used. For
 443                         <varname>z</varname>, <varname>Z</varname>
 444                         lines, when omitted or when set to -, the file
 445                         ownership will not be modified. These
 446                         parameters are ignored for
 447                         <varname>x</varname>, <varname>r</varname>,
 448                         <varname>R</varname>, <varname>L</varname>
 449                         lines.</para>
 450                 </refsect2>
 451
 452                 <refsect2>
 453                         <title>Age</title>
 454                         <para>The date field, when set, is used to
 455                         decide what files to delete when cleaning. If
 456                         a file or directory is older than the current
 457                         time minus the age field, it is deleted. The
 458                         field format is a series of integers each
 459                         followed by one of the following
 460                         postfixes for the respective time units:</para>
 461
 462                         <variablelist>
 463                                 <varlistentry>
 464                                 <term><varname>s</varname></term>
 465                                 <term><varname>min</varname></term>
 466                                 <term><varname>h</varname></term>
 467                                 <term><varname>d</varname></term>
 468                                 <term><varname>w</varname></term>
 469                                 <term><varname>ms</varname></term>
 470                                 <term><varname>m</varname></term>
 471                                 <term><varname>us</varname></term></varlistentry>
 472                         </variablelist>
 473
 474                         <para>If multiple integers and units are specified, the time
 475                         values are summed up. If an integer is given without a unit,
 476                         s is assumed.
 477                         </para>
 478
 479                         <para>When the age is set to zero, the files are cleaned
 480                         unconditionally.</para>
 481
 482                         <para>The age field only applies to lines
 483                         starting with <varname>d</varname>,
 484                         <varname>D</varname>, and
 485                         <varname>x</varname>. If omitted or set to
 486                         <literal>-</literal>, no automatic clean-up is
 487                         done.</para>
 488
 489                         <para>If the age field starts with a tilde
 490                         character <literal>~</literal>, the clean-up
 491                         is only applied to files and directories one
 492                         level inside the directory specified, but not
 493                         the files and directories immediately inside
 494                         it.</para>
 495                 </refsect2>
 496
 497                 <refsect2>
 498                         <title>Argument</title>
 499
 500                         <para>For <varname>L</varname> lines
 501                         determines the destination path of the
 502                         symlink. For <varname>c</varname>,
 503                         <varname>b</varname> determines the
 504                         major/minor of the device node, with major and
 505                         minor formatted as integers, separated by
 506                         <literal>:</literal>, e.g.
 507                         <literal>1:3</literal>. For
 508                         <varname>f</varname>, <varname>F</varname>,
 509                         and <varname>w</varname> may be used to
 510                         specify a short string that is written to the
 511                         file, suffixed by a newline. For
 512                         <varname>C</varname> specifies the source file
 513                         or directory. Ignored for all other
 514                         lines.</para>
 515                 </refsect2>
 516
 517         </refsect1>
 518
 519         <refsect1>
 520                 <title>Example</title>
 521                 <example>
 522                         <title>/etc/tmpfiles.d/screen.conf example</title>
 523                         <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
 524
 525                         <programlisting>d /run/screens  1777 root root 10d
 526 d /run/uscreens 0755 root root 10d12h</programlisting>
 527                 </example>
 528                 <example>
 529                         <title>/etc/tmpfiles.d/abrt.conf example</title>
 530                         <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
 531
 532                         <programlisting>d /var/tmp/abrt 0755 abrt abrt
 533 x /var/tmp/abrt/*</programlisting>
 534                 </example>
 535         </refsect1>
 536
 537         <refsect1>
 538                 <title>See Also</title>
 539                 <para>
 540                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 541                         <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 542                         <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 543                         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 544                 </para>
 545         </refsect1>
 546
 547 </refentry>