man/tmpfiles.d.xml

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   7   Copyright 2010 Brandon Philips
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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.
 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>v</varname></term>
 172                                         <listitem><para>Create a
 173                                         subvolume if the path does not
 174                                         exist yet and the file system
 175                                         supports this (btrfs). Otherwise
 176                                         create a normal directory, in
 177                                         the same way as
 178                                         <varname>d</varname>.</para></listitem>
 179                                 </varlistentry>
 180
 181                                 <varlistentry>
 182                                         <term><varname>p</varname></term>
 183                                         <term><varname>p+</varname></term>
 184                                         <listitem><para>Create a named
 185                                         pipe (FIFO) if it does not
 186                                         exist yet. If suffixed with
 187                                         <varname>+</varname> and a
 188                                         file already exists where the
 189                                         pipe is to be created, it will
 190                                         be removed and be replaced by
 191                                         the pipe.</para></listitem>
 192                                 </varlistentry>
 193
 194                                 <varlistentry>
 195                                         <term><varname>L</varname></term>
 196                                         <term><varname>L+</varname></term>
 197                                         <listitem><para>Create a
 198                                         symlink if it does not exist
 199                                         yet. If suffixed with
 200                                         <varname>+</varname> and a
 201                                         file already exists where the
 202                                         symlink is to be created, it
 203                                         will be removed and be
 204                                         replaced by the
 205                                         symlink. If the argument is omitted,
 206                                         symlinks to files with the same name
 207                                         residing in the directory
 208                                         <filename>/usr/share/factory/</filename>
 209                                         are created.</para></listitem>
 210                                 </varlistentry>
 211
 212                                 <varlistentry>
 213                                         <term><varname>c</varname></term>
 214                                         <term><varname>c+</varname></term>
 215                                         <listitem><para>Create a
 216                                         character device node if it
 217                                         does not exist yet. If
 218                                         suffixed with
 219                                         <varname>+</varname> and a
 220                                         file already exists where the
 221                                         device node is to be created,
 222                                         it will be removed and be
 223                                         replaced by the device
 224                                         node. It is recommended to suffix this
 225                                         entry with an exclamation mark to only
 226                                         create static device nodes at boot,
 227                                         as udev will not manage static device
 228                                         nodes that are created at runtime.
 229                                         </para></listitem>
 230                                 </varlistentry>
 231
 232                                 <varlistentry>
 233                                         <term><varname>b</varname></term>
 234                                         <term><varname>b+</varname></term>
 235                                         <listitem><para>Create a block
 236                                         device node if it does not
 237                                         exist yet. If suffixed with
 238                                         <varname>+</varname> and a
 239                                         file already exists where the
 240                                         device node is to be created,
 241                                         it will be removed and be
 242                                         replaced by the device
 243                                         node. It is recommended to suffix this
 244                                         entry with an exclamation mark to only
 245                                         create static device nodes at boot,
 246                                         as udev will not manage static device
 247                                         nodes that are created at runtime.
 248                                         </para></listitem>
 249                                 </varlistentry>
 250
 251                                 <varlistentry>
 252                                         <term><varname>C</varname></term>
 253                                         <listitem><para>Recursively
 254                                         copy a file or directory, if
 255                                         the destination files or
 256                                         directories do not exist
 257                                         yet. Note that this command
 258                                         will not descend into
 259                                         subdirectories if the
 260                                         destination directory already
 261                                         exists. Instead, the entire
 262                                         copy operation is
 263                                         skipped. If the argument is omitted,
 264                                         files from the source directory
 265                                         <filename>/usr/share/factory/</filename>
 266                                         with the same name are copied.</para></listitem>
 267                                 </varlistentry>
 268
 269                                 <varlistentry>
 270                                         <term><varname>x</varname></term>
 271                                         <listitem><para>Ignore a path
 272                                         during cleaning. Use this type
 273                                         to exclude paths from clean-up
 274                                         as controlled with the Age
 275                                         parameter. Note that lines of
 276                                         this type do not influence the
 277                                         effect of <varname>r</varname>
 278                                         or <varname>R</varname> lines.
 279                                         Lines of this type accept
 280                                         shell-style globs in place of
 281                                         normal path names.
 282                                         </para></listitem>
 283                                 </varlistentry>
 284
 285                                 <varlistentry>
 286                                         <term><varname>X</varname></term>
 287                                         <listitem><para>Ignore a path
 288                                         during cleaning. Use this type
 289                                         to exclude paths from clean-up
 290                                         as controlled with the Age
 291                                         parameter. Unlike
 292                                         <varname>x</varname>, this
 293                                         parameter will not exclude the
 294                                         content if path is a
 295                                         directory, but only directory
 296                                         itself. Note that lines of
 297                                         this type do not influence the
 298                                         effect of <varname>r</varname>
 299                                         or <varname>R</varname> lines.
 300                                         Lines of this type accept
 301                                         shell-style globs in place of
 302                                         normal path names.
 303                                         </para></listitem>
 304                                 </varlistentry>
 305
 306                                 <varlistentry>
 307                                         <term><varname>r</varname></term>
 308                                         <listitem><para>Remove a file
 309                                         or directory if it exists.
 310                                         This may not be used to remove
 311                                         non-empty directories, use
 312                                         <varname>R</varname> for that.
 313                                         Lines of this type accept
 314                                         shell-style globs in place of
 315                                         normal path
 316                                         names.</para></listitem>
 317                                 </varlistentry>
 318
 319                                 <varlistentry>
 320                                         <term><varname>R</varname></term>
 321                                         <listitem><para>Recursively
 322                                         remove a path and all its
 323                                         subdirectories (if it is a
 324                                         directory). Lines of this type
 325                                         accept shell-style globs in
 326                                         place of normal path
 327                                         names.</para></listitem>
 328                                 </varlistentry>
 329
 330                                 <varlistentry>
 331                                         <term><varname>z</varname></term>
 332                                         <listitem><para>Adjust the
 333                                         access mode, group and user,
 334                                         and restore the SELinux security
 335                                         context of a file or directory,
 336                                         if it exists. Lines of this
 337                                         type accept shell-style globs
 338                                         in place of normal path names.
 339                                         </para></listitem>
 340                                 </varlistentry>
 341
 342                                 <varlistentry>
 343                                         <term><varname>Z</varname></term>
 344                                         <listitem><para>Recursively
 345                                         set the access mode, group and
 346                                         user, and restore the SELinux
 347                                         security context of a file or
 348                                         directory if it exists, as
 349                                         well as of its subdirectories
 350                                         and the files contained
 351                                         therein (if applicable). Lines
 352                                         of this type accept
 353                                         shell-style globs in place of
 354                                         normal path
 355                                         names.</para></listitem>
 356                                 </varlistentry>
 357
 358                                 <varlistentry>
 359                                         <term><varname>t</varname></term>
 360                                         <listitem><para>Set extended
 361                                         attributes on item. It may be
 362                                         used in conjunction with other
 363                                         types (only <varname>d</varname>,
 364                                         <varname>D</varname>, <varname>f</varname>,
 365                                         <varname>F</varname>, <varname>L</varname>,
 366                                         <varname>p</varname>, <varname>c</varname>,
 367                                         <varname>b</varname>, makes sense).
 368                                         If used as a standalone line, then
 369                                         <command>systemd-tmpfiles</command>
 370                                         will try to set extended
 371                                         attributes on specified path.
 372                                         This can be especially used to set
 373                                         SMACK labels.
 374                                         </para></listitem>
 375                                 </varlistentry>
 376                         </variablelist>
 377
 378                         <para>If the exclamation mark is used, this
 379                         line is only safe of execute during boot, and
 380                         can break a running system. Lines without the
 381                         exclamation mark are presumed to be safe to
 382                         execute at any time, e.g. on package upgrades.
 383                         <command>systemd-tmpfiles</command> will
 384                         execute line with an exclamation mark only if
 385                         option <option>--boot</option> is given.
 386                         </para>
 387
 388                         <para>For example:
 389                         <programlisting># Make sure these are created by default so that nobody else can
 390 d /tmp/.X11-unix 1777 root root 10d
 391
 392 # Unlink the X11 lock files
 393 r! /tmp/.X[0-9]*-lock</programlisting>
 394                         The second line in contrast to the first one
 395                         would break a running system, and will only be
 396                         executed with <option>--boot</option>.</para>
 397                 </refsect2>
 398
 399                 <refsect2>
 400                         <title>Path</title>
 401
 402                         <para>The file system path specification supports simple specifier
 403                         expansion. The following expansions are
 404                         understood:</para>
 405
 406                         <table>
 407                                 <title>Specifiers available</title>
 408                                 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
 409                                         <colspec colname="spec" />
 410                                         <colspec colname="mean" />
 411                                         <colspec colname="detail" />
 412                                         <thead>
 413                                                 <row>
 414                                                         <entry>Specifier</entry>
 415                                                         <entry>Meaning</entry>
 416                                                         <entry>Details</entry>
 417                                                 </row>
 418                                         </thead>
 419                                         <tbody>
 420                                                 <row>
 421                                                         <entry><literal>%m</literal></entry>
 422                                                         <entry>Machine ID</entry>
 423                                                         <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>
 424                                                 </row>
 425                                                 <row>
 426                                                         <entry><literal>%b</literal></entry>
 427                                                         <entry>Boot ID</entry>
 428                                                         <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
 429                                                 </row>
 430                                                 <row>
 431                                                         <entry><literal>%H</literal></entry>
 432                                                         <entry>Host name</entry>
 433                                                         <entry>The hostname of the running system.</entry>
 434                                                 </row>
 435                                                 <row>
 436                                                         <entry><literal>%v</literal></entry>
 437                                                         <entry>Kernel release</entry>
 438                                                         <entry>Identical to <command>uname -r</command> output.</entry>
 439                                                 </row>
 440                                                 <row>
 441                                                         <entry><literal>%%</literal></entry>
 442                                                         <entry>Escaped %</entry>
 443                                                         <entry>Single percent sign.</entry>
 444                                                 </row>
 445                                         </tbody>
 446                                 </tgroup>
 447                         </table>
 448                 </refsect2>
 449
 450                 <refsect2>
 451                         <title>Mode</title>
 452
 453                         <para>The file access mode to use when
 454                         creating this file or directory. If omitted or
 455                         when set to -, the default is used: 0755 for
 456                         directories, 0644 for all other file objects.
 457                         For <varname>z</varname>, <varname>Z</varname>
 458                         lines, if omitted or when set to
 459                         <literal>-</literal>, the file access mode
 460                         will not be modified. This parameter is
 461                         ignored for <varname>x</varname>,
 462                         <varname>r</varname>, <varname>R</varname>,
 463                         <varname>L</varname>, <varname>t</varname> lines.</para>
 464
 465                         <para>Optionally, if prefixed with
 466                         <literal>~</literal>, the access mode is masked
 467                         based on the already set access bits for
 468                         existing file or directories: if the existing
 469                         file has all executable bits unset, all
 470                         executable bits are removed from the new
 471                         access mode, too. Similarly, if all read bits
 472                         are removed from the old access mode, they will
 473                         be removed from the new access mode too, and
 474                         if all write bits are removed, they will be
 475                         removed from the new access mode too. In
 476                         addition, the sticky/SUID/SGID bit is removed unless
 477                         applied to a directory. This
 478                         functionality is particularly useful in
 479                         conjunction with <varname>Z</varname>.</para>
 480                 </refsect2>
 481
 482                 <refsect2>
 483                         <title>UID, GID</title>
 484
 485                         <para>The user and group to use for this file
 486                         or directory. This may either be a numeric
 487                         user/group ID or a user or group name. If
 488                         omitted or when set to <literal>-</literal>,
 489                         the default 0 (root) is used. For
 490                         <varname>z</varname>, <varname>Z</varname>
 491                         lines, when omitted or when set to -, the file
 492                         ownership will not be modified. These
 493                         parameters are ignored for
 494                         <varname>x</varname>, <varname>r</varname>,
 495                         <varname>R</varname>, <varname>L</varname>,
 496                         <varname>t</varname> lines.</para>
 497                 </refsect2>
 498
 499                 <refsect2>
 500                         <title>Age</title>
 501                         <para>The date field, when set, is used to
 502                         decide what files to delete when cleaning. If
 503                         a file or directory is older than the current
 504                         time minus the age field, it is deleted. The
 505                         field format is a series of integers each
 506                         followed by one of the following
 507                         postfixes for the respective time units:</para>
 508
 509                         <variablelist>
 510                                 <varlistentry>
 511                                 <term><varname>s</varname></term>
 512                                 <term><varname>min</varname></term>
 513                                 <term><varname>h</varname></term>
 514                                 <term><varname>d</varname></term>
 515                                 <term><varname>w</varname></term>
 516                                 <term><varname>ms</varname></term>
 517                                 <term><varname>m</varname></term>
 518                                 <term><varname>us</varname></term></varlistentry>
 519                         </variablelist>
 520
 521                         <para>If multiple integers and units are specified, the time
 522                         values are summed up. If an integer is given without a unit,
 523                         s is assumed.
 524                         </para>
 525
 526                         <para>When the age is set to zero, the files are cleaned
 527                         unconditionally.</para>
 528
 529                         <para>The age field only applies to lines
 530                         starting with <varname>d</varname>,
 531                         <varname>D</varname>, and
 532                         <varname>x</varname>. If omitted or set to
 533                         <literal>-</literal>, no automatic clean-up is
 534                         done.</para>
 535
 536                         <para>If the age field starts with a tilde
 537                         character <literal>~</literal>, the clean-up
 538                         is only applied to files and directories one
 539                         level inside the directory specified, but not
 540                         the files and directories immediately inside
 541                         it.</para>
 542                 </refsect2>
 543
 544                 <refsect2>
 545                         <title>Argument</title>
 546
 547                         <para>For <varname>L</varname> lines
 548                         determines the destination path of the
 549                         symlink. For <varname>c</varname>,
 550                         <varname>b</varname> determines the
 551                         major/minor of the device node, with major and
 552                         minor formatted as integers, separated by
 553                         <literal>:</literal>, e.g.
 554                         <literal>1:3</literal>. For
 555                         <varname>f</varname>, <varname>F</varname>,
 556                         and <varname>w</varname> may be used to
 557                         specify a short string that is written to the
 558                         file, suffixed by a newline. For
 559                         <varname>C</varname>, specifies the source file
 560                         or directory. For <varname>t</varname> determines
 561                         extended attributes to be set. Ignored for all other lines.</para>
 562                 </refsect2>
 563
 564         </refsect1>
 565
 566         <refsect1>
 567                 <title>Example</title>
 568                 <example>
 569                         <title>/etc/tmpfiles.d/screen.conf example</title>
 570                         <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
 571
 572                         <programlisting>d /run/screens  1777 root root 10d
 573 d /run/uscreens 0755 root root 10d12h
 574 t /run/screen - - - - user.name="John Smith" security.SMACK64=screen</programlisting>
 575                 </example>
 576                 <example>
 577                         <title>/etc/tmpfiles.d/abrt.conf example</title>
 578                         <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
 579
 580                         <programlisting>d /var/tmp/abrt 0755 abrt abrt
 581 x /var/tmp/abrt/*</programlisting>
 582                 </example>
 583         </refsect1>
 584
 585         <refsect1>
 586                 <title>See Also</title>
 587                 <para>
 588                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 589                         <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 590                         <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 591                         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 592                 </para>
 593         </refsect1>
 594
 595 </refentry>