man/tmpfiles.d.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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   4   SPDX-License-Identifier: LGPL-2.1+
   5
   6   Copyright © 2010 Brandon Philips
   7 -->
   8 <refentry id="tmpfiles.d">
   9
  10   <refentryinfo>
  11     <title>tmpfiles.d</title>
  12     <productname>systemd</productname>
  13   </refentryinfo>
  14
  15   <refmeta>
  16     <refentrytitle>tmpfiles.d</refentrytitle>
  17     <manvolnum>5</manvolnum>
  18   </refmeta>
  19
  20   <refnamediv>
  21     <refname>tmpfiles.d</refname>
  22     <refpurpose>Configuration for creation, deletion and cleaning of
  23     volatile and temporary files</refpurpose>
  24   </refnamediv>
  25
  26   <refsynopsisdiv>
  27     <para><literallayout><filename>/etc/tmpfiles.d/*.conf</filename>
  28 <filename>/run/tmpfiles.d/*.conf</filename>
  29 <filename>/usr/lib/tmpfiles.d/*.conf</filename>
  30     </literallayout></para>
  31
  32     <para><literallayout><filename>~/.config/user-tmpfiles.d/*.conf</filename>
  33 <filename>$XDG_RUNTIME_DIR/user-tmpfiles.d/*.conf</filename>
  34 <filename>~/.local/share/user-tmpfiles.d/*.conf</filename>
  35 <filename>…</filename>
  36 <filename>/usr/share/user-tmpfiles.d/*.conf</filename>
  37     </literallayout></para>
  38   </refsynopsisdiv>
  39
  40   <refsect1>
  41     <title>Description</title>
  42
  43     <para><command>systemd-tmpfiles</command> uses the configuration
  44     files from the above directories to describe the creation,
  45     cleaning and removal of volatile and temporary files and
  46     directories which usually reside in directories such as
  47     <filename>/run</filename> or <filename>/tmp</filename>.</para>
  48
  49     <para>Volatile and temporary files and directories are those
  50     located in <filename>/run</filename> (and its alias
  51     <filename>/var/run</filename>), <filename>/tmp</filename>,
  52     <filename>/var/tmp</filename>, the API file systems such as
  53     <filename>/sys</filename> or <filename>/proc</filename>, as well
  54     as some other directories below <filename>/var</filename>.</para>
  55
  56     <para>System daemons frequently require private runtime
  57     directories below <filename>/run</filename> to place communication
  58     sockets and similar in. For these, consider declaring them in
  59     their unit files using <varname>RuntimeDirectory=</varname> (see
  60     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  61     for details), if this is feasible.</para>
  62   </refsect1>
  63
  64   <refsect1>
  65     <title>Configuration Directories and Precedence</title>
  66
  67     <para>Each configuration file shall be named in the style of
  68     <filename><replaceable>package</replaceable>.conf</filename> or
  69     <filename><replaceable>package</replaceable>-<replaceable>part</replaceable>.conf</filename>.
  70     The second variant should be used when it is desirable to make it
  71     easy to override just this part of configuration.</para>
  72
  73     <para>Files in <filename>/etc/tmpfiles.d</filename> override files
  74     with the same name in <filename>/usr/lib/tmpfiles.d</filename> and
  75     <filename>/run/tmpfiles.d</filename>. Files in
  76     <filename>/run/tmpfiles.d</filename> override files with the same
  77     name in <filename>/usr/lib/tmpfiles.d</filename>. Packages should
  78     install their configuration files in
  79     <filename>/usr/lib/tmpfiles.d</filename>. Files in
  80     <filename>/etc/tmpfiles.d</filename> are reserved for the local
  81     administrator, who may use this logic to override the
  82     configuration files installed by vendor packages. All
  83     configuration files are sorted by their filename in lexicographic
  84     order, regardless of which of the directories they reside in. If
  85     multiple files specify the same path, the entry in the file with
  86     the lexicographically earliest name will be applied.  All other
  87     conflicting entries will be logged as errors. When two lines are
  88     prefix and suffix of each other, then the prefix is always
  89     processed first, the suffix later. Lines that take globs are
  90     applied after those accepting no globs. If multiple operations
  91     shall be applied on the same file, (such as ACL, xattr, file
  92     attribute adjustments), these are always done in the same fixed
  93     order. Otherwise, the files/directories are processed in the order
  94     they are listed.</para>
  95
  96     <para>If the administrator wants to disable a configuration file
  97     supplied by the vendor, the recommended way is to place a symlink
  98     to <filename>/dev/null</filename> in
  99     <filename>/etc/tmpfiles.d/</filename> bearing the same filename.
 100     </para>
 101   </refsect1>
 102
 103   <refsect1>
 104     <title>Configuration File Format</title>
 105
 106     <para>The configuration format is one line per path containing
 107     type, path, mode, ownership, age, and argument fields:</para>
 108
 109     <programlisting>#Type Path        Mode UID  GID  Age Argument
 110 d     /run/user   0755 root root 10d -
 111 L     /tmp/foobar -    -    -    -   /dev/null</programlisting>
 112
 113     <para>Fields may be enclosed within quotes and contain C-style escapes.</para>
 114
 115     <refsect2>
 116       <title>Type</title>
 117
 118       <para>The type consists of a single letter and optionally an
 119       exclamation mark and/or minus sign.</para>
 120
 121       <para>The following line types are understood:</para>
 122
 123       <variablelist>
 124         <varlistentry>
 125           <term><varname>f</varname></term>
 126           <listitem><para>Create a file if it does not exist yet. If the argument parameter is given and the file did
 127           not exist yet, it will be written to the file. Does not follow symlinks.</para></listitem>
 128         </varlistentry>
 129
 130         <varlistentry>
 131           <term><varname>F</varname></term>
 132           <listitem><para>Create or truncate a file. If the argument
 133           parameter is given, it will be written to the file. Does not follow symlinks.</para>
 134           </listitem>
 135         </varlistentry>
 136
 137         <varlistentry>
 138           <term><varname>w</varname></term>
 139           <listitem><para>Write the argument parameter to a file, if
 140           the file exists.  Lines of this type accept shell-style
 141           globs in place of normal path names. The argument parameter
 142           will be written without a trailing newline. C-style
 143           backslash escapes are interpreted. Follows
 144           symlinks.</para></listitem>
 145         </varlistentry>
 146
 147         <varlistentry>
 148           <term><varname>d</varname></term>
 149           <listitem><para>Create a directory. The mode and ownership will be adjusted if
 150           specified and the directory already exists. Contents of this directory are subject
 151           to time based cleanup if the age argument is specified.</para></listitem>
 152         </varlistentry>
 153
 154         <varlistentry>
 155           <term><varname>D</varname></term>
 156           <listitem><para>Similar to <varname>d</varname>, but in addition the contents
 157           of the directory will be removed when <option>--remove</option> is used.
 158           </para></listitem>
 159         </varlistentry>
 160
 161         <varlistentry>
 162           <term><varname>e</varname></term>
 163           <listitem><para>Similar to <varname>d</varname>, but the directory will not be created if
 164           it does not exist. Lines of this type accept shell-style globs in place of normal path
 165           names. For this entry to be useful, at least one of the mode, uid, gid, or age arguments
 166           must be specified, since otherwise this entry has no effect. If the age argument is
 167           <literal>0</literal>, contents of the directory will be unconditionally deleted every time
 168           <command>systemd-tmpfiles --clean</command> is run. This can be useful when combined with
 169           <varname>!</varname>, see the examples.</para></listitem>
 170         </varlistentry>
 171
 172         <varlistentry>
 173           <term><varname>v</varname></term>
 174           <listitem><para>Create a subvolume if the path does not
 175           exist yet, the file system supports subvolumes (btrfs), and
 176           the system itself is installed into a subvolume
 177           (specifically: the root directory <filename>/</filename> is
 178           itself a subvolume). Otherwise, create a normal directory, in
 179           the same way as <varname>d</varname>. A subvolume created
 180           with this line type is not assigned to any higher-level
 181           quota group. For that, use <varname>q</varname> or
 182           <varname>Q</varname>, which allow creating simple quota
 183           group hierarchies, see below.</para></listitem>
 184         </varlistentry>
 185
 186         <varlistentry>
 187           <term><varname>q</varname></term>
 188           <listitem><para>Similar to <varname>v</varname>. However, makes sure that the subvolume will be assigned to
 189           the same higher-level quota groups as the subvolume it has been created in. This ensures that higher-level
 190           limits and accounting applied to the parent subvolume also include the specified subvolume. On non-btrfs file
 191           systems, this line type is identical to <varname>d</varname>.</para>
 192
 193           <para>If the subvolume already exists, no change to the quota hierarchy is made, regardless of whether the
 194           subvolume is already attached to a quota group or not. Also see <varname>Q</varname> below. See <citerefentry
 195           project='die-net'><refentrytitle>btrfs-qgroup</refentrytitle><manvolnum>8</manvolnum></citerefentry> for
 196           details about the btrfs quota group concept.</para></listitem>
 197         </varlistentry>
 198
 199         <varlistentry>
 200           <term><varname>Q</varname></term>
 201           <listitem><para>Similar to <varname>q</varname>. However, instead of copying the higher-level quota group
 202           assignments from the parent as-is, the lowest quota group of the parent subvolume is determined that is not
 203           the leaf quota group. Then, an "intermediary" quota group is inserted that is one level below this level, and
 204           shares the same ID part as the specified subvolume. If no higher-level quota group exists for the parent
 205           subvolume, a new quota group at level 255 sharing the same ID as the specified subvolume is inserted
 206           instead. This new intermediary quota group is then assigned to the parent subvolume's higher-level quota
 207           groups, and the specified subvolume's leaf quota group is assigned to it.</para>
 208
 209           <para>Effectively, this has a similar effect as <varname>q</varname>, however introduces a new higher-level
 210           quota group for the specified subvolume that may be used to enforce limits and accounting to the specified
 211           subvolume and children subvolume created within it. Thus, by creating subvolumes only via
 212           <varname>q</varname> and <varname>Q</varname>, a concept of "subtree quotas" is implemented. Each subvolume
 213           for which <varname>Q</varname> is set will get a "subtree" quota group created, and all child subvolumes
 214           created within it will be assigned to it. Each subvolume for which <varname>q</varname> is set will not get
 215           such a "subtree" quota group, but it is ensured that they are added to the same "subtree" quota group as
 216           their immediate parents.</para>
 217
 218           <para>It is recommended to use <varname>Q</varname> for subvolumes that typically contain further subvolumes,
 219           and where it is desirable to have accounting and quota limits on all child subvolumes together. Examples for
 220           <varname>Q</varname> are typically <filename>/home</filename> or <filename>/var/lib/machines</filename>. In
 221           contrast, <varname>q</varname> should be used for subvolumes that either usually do not include further
 222           subvolumes or where no accounting and quota limits are needed that apply to all child subvolumes
 223           together. Examples for <varname>q</varname> are typically <filename>/var</filename> or
 224           <filename>/var/tmp</filename>. </para>
 225
 226           <para>As with <varname>q</varname>, <varname>Q</varname> has no effect on the quota group hierarchy if the
 227           subvolume already exists, regardless of whether the subvolume already belong to a quota group or
 228           not.</para></listitem>
 229         </varlistentry>
 230
 231         <varlistentry>
 232           <term><varname>p</varname></term>
 233           <term><varname>p+</varname></term>
 234           <listitem><para>Create a named pipe (FIFO) if it does not
 235           exist yet. If suffixed with <varname>+</varname> and a file
 236           already exists where the pipe is to be created, it will be
 237           removed and be replaced by the pipe.</para></listitem>
 238         </varlistentry>
 239
 240         <varlistentry>
 241           <term><varname>L</varname></term>
 242           <term><varname>L+</varname></term>
 243           <listitem><para>Create a symlink if it does not exist
 244           yet. If suffixed with <varname>+</varname> and a file or
 245           directory already exists where the symlink is to be created,
 246           it will be removed and be replaced by the symlink. If the
 247           argument is omitted, symlinks to files with the same name
 248           residing in the directory
 249           <filename>/usr/share/factory/</filename> are created. Note
 250           that permissions and ownership on symlinks are ignored.
 251           </para></listitem>
 252         </varlistentry>
 253
 254         <varlistentry>
 255           <term><varname>c</varname></term>
 256           <term><varname>c+</varname></term>
 257           <listitem><para>Create a character device node if it does
 258           not exist yet. If suffixed with <varname>+</varname> and a
 259           file already exists where the device node is to be created,
 260           it will be removed and be replaced by the device node. It is
 261           recommended to suffix this entry with an exclamation mark to
 262           only create static device nodes at boot, as udev will not
 263           manage static device nodes that are created at runtime.
 264           </para></listitem>
 265         </varlistentry>
 266
 267         <varlistentry>
 268           <term><varname>b</varname></term>
 269           <term><varname>b+</varname></term>
 270           <listitem><para>Create a block device node if it does not
 271           exist yet. If suffixed with <varname>+</varname> and a file
 272           already exists where the device node is to be created, it
 273           will be removed and be replaced by the device node. It is
 274           recommended to suffix this entry with an exclamation mark to
 275           only create static device nodes at boot, as udev will not
 276           manage static device nodes that are created at runtime.
 277           </para></listitem>
 278         </varlistentry>
 279
 280         <varlistentry>
 281           <term><varname>C</varname></term>
 282           <listitem><para>Recursively copy a file or directory, if the
 283           destination files or directories do not exist yet. Note that
 284           this command will not descend into subdirectories if the
 285           destination directory already exists. Instead, the entire
 286           copy operation is skipped. If the argument is omitted, files
 287           from the source directory
 288           <filename>/usr/share/factory/</filename> with the same name
 289           are copied. Does not follow symlinks.</para></listitem>
 290         </varlistentry>
 291
 292         <varlistentry>
 293           <term><varname>x</varname></term>
 294           <listitem><para>Ignore a path during cleaning. Use this type
 295           to exclude paths from clean-up as controlled with the Age
 296           parameter. Note that lines of this type do not influence the
 297           effect of <varname>r</varname> or <varname>R</varname>
 298           lines. Lines of this type accept shell-style globs in place
 299           of normal path names.  </para></listitem>
 300         </varlistentry>
 301
 302         <varlistentry>
 303           <term><varname>X</varname></term>
 304           <listitem><para>Ignore a path during cleaning. Use this type
 305           to exclude paths from clean-up as controlled with the Age
 306           parameter. Unlike <varname>x</varname>, this parameter will
 307           not exclude the content if path is a directory, but only
 308           directory itself. Note that lines of this type do not
 309           influence the effect of <varname>r</varname> or
 310           <varname>R</varname> lines. Lines of this type accept
 311           shell-style globs in place of normal path names.
 312           </para></listitem>
 313         </varlistentry>
 314
 315         <varlistentry>
 316           <term><varname>r</varname></term>
 317           <listitem><para>Remove a file or directory if it exists.
 318           This may not be used to remove non-empty directories, use
 319           <varname>R</varname> for that.  Lines of this type accept
 320           shell-style globs in place of normal path
 321           names. Does not follow symlinks.</para></listitem>
 322         </varlistentry>
 323
 324         <varlistentry>
 325           <term><varname>R</varname></term>
 326           <listitem><para>Recursively remove a path and all its
 327           subdirectories (if it is a directory). Lines of this type
 328           accept shell-style globs in place of normal path
 329           names. Does not follow symlinks.</para></listitem>
 330         </varlistentry>
 331
 332         <varlistentry>
 333           <term><varname>z</varname></term>
 334           <listitem><para>Adjust the access mode, group and user, and
 335           restore the SELinux security context of a file or directory,
 336           if it exists. Lines of this type accept shell-style globs in
 337           place of normal path names. Does not follow symlinks.</para></listitem>
 338         </varlistentry>
 339
 340         <varlistentry>
 341           <term><varname>Z</varname></term>
 342           <listitem><para>Recursively set the access mode, group and
 343           user, and restore the SELinux security context of a file or
 344           directory if it exists, as well as of its subdirectories and
 345           the files contained therein (if applicable). Lines of this
 346           type accept shell-style globs in place of normal path
 347           names. Does not follow symlinks.  </para></listitem>
 348         </varlistentry>
 349
 350         <varlistentry>
 351           <term><varname>t</varname></term>
 352           <listitem><para>Set extended attributes. Lines of this type
 353           accept shell-style globs in place of normal path names.
 354           This can be useful for setting SMACK labels. Does not follow
 355           symlinks.</para></listitem>
 356         </varlistentry>
 357
 358         <varlistentry>
 359           <term><varname>T</varname></term>
 360           <listitem><para>Recursively set extended attributes. Lines
 361           of this type accept shell-style globs in place of normal
 362           path names.  This can be useful for setting SMACK
 363           labels. Does not follow symlinks.  </para></listitem>
 364         </varlistentry>
 365
 366         <varlistentry>
 367           <term><varname>h</varname></term>
 368           <listitem><para>Set file/directory attributes. Lines of this type
 369           accept shell-style globs in place of normal path names.</para>
 370
 371           <para>The format of the argument field is
 372           <varname>[+-=][aAcCdDeijsStTu] </varname>. The prefix
 373           <varname>+</varname> (the default one) causes the
 374           attribute(s) to be added; <varname>-</varname> causes the
 375           attribute(s) to be removed; <varname>=</varname> causes the
 376           attributes to be set exactly as the following letters. The
 377           letters <literal>aAcCdDeijsStTu</literal> select the new
 378           attributes for the files, see
 379           <citerefentry project='man-pages'><refentrytitle>chattr</refentrytitle>
 380           <manvolnum>1</manvolnum></citerefentry> for further information.
 381           </para>
 382           <para>Passing only <varname>=</varname> as argument resets
 383           all the file attributes listed above. It has to be pointed
 384           out that the <varname>=</varname> prefix limits itself to
 385           the attributes corresponding to the letters listed here. All
 386           other attributes will be left untouched. Does not follow
 387           symlinks.</para>
 388           </listitem>
 389         </varlistentry>
 390
 391         <varlistentry>
 392           <term><varname>H</varname></term>
 393           <listitem><para>Recursively set file/directory attributes. Lines
 394           of this type accept shell-style globs in place of normal
 395           path names. Does not follow symlinks.
 396           </para></listitem>
 397         </varlistentry>
 398
 399         <varlistentry>
 400           <term><varname>a</varname></term>
 401           <term><varname>a+</varname></term>
 402           <listitem><para>Set POSIX ACLs (access control lists). If
 403           suffixed with <varname>+</varname>, the specified entries will
 404           be added to the existing set.
 405           <command>systemd-tmpfiles</command> will automatically add
 406           the required base entries for user and group based on the
 407           access mode of the file, unless base entries already exist
 408           or are explicitly specified. The mask will be added if not
 409           specified explicitly or already present. Lines of this type
 410           accept shell-style globs in place of normal path names. This
 411           can be useful for allowing additional access to certain
 412           files. Does not follow symlinks.</para></listitem>
 413         </varlistentry>
 414
 415         <varlistentry>
 416           <term><varname>A</varname></term>
 417           <term><varname>A+</varname></term>
 418           <listitem><para>Same as <varname>a</varname> and
 419           <varname>a+</varname>, but recursive. Does not follow
 420           symlinks.</para></listitem>
 421         </varlistentry>
 422       </variablelist>
 423
 424       <para>If the exclamation mark is used, this line is only safe of
 425       execute during boot, and can break a running system. Lines
 426       without the exclamation mark are presumed to be safe to execute
 427       at any time, e.g. on package upgrades.
 428       <command>systemd-tmpfiles</command> will execute line with an
 429       exclamation mark only if option <option>--boot</option> is
 430       given.</para>
 431
 432       <para>For example:
 433       <programlisting># Make sure these are created by default so that nobody else can
 434 d /tmp/.X11-unix 1777 root root 10d
 435
 436 # Unlink the X11 lock files
 437 r! /tmp/.X[0-9]*-lock</programlisting>
 438       The second line in contrast to the first one would break a
 439       running system, and will only be executed with
 440       <option>--boot</option>.</para>
 441
 442       <para>If the minus sign is used, this line failing to run
 443       successfully during create (and only create) will not cause
 444       the execution of <command>systemd-tmpfiles</command> to return
 445       an error.</para>
 446
 447       <para>For example:
 448       <programlisting># Modify sysfs but don't fail if we are in a container with a read-only /proc
 449 w- /proc/sys/vm/swappiness - - - - 10</programlisting></para>
 450
 451       <para>Note that for all line types that result in creation of any kind of file node
 452       (i.e. <varname>f</varname>/<varname>F</varname>,
 453       <varname>d</varname>/<varname>D</varname>/<varname>v</varname>/<varname>q</varname>/<varname>Q</varname>,
 454       <varname>p</varname>, <varname>L</varname>, <varname>c</varname>/<varname>b</varname> and <varname>C</varname>)
 455       leading directories are implicitly created if needed, owned by root with an access mode of 0755. In order to
 456       create them with different modes or ownership make sure to add appropriate <varname>d</varname> lines.</para>
 457     </refsect2>
 458
 459     <refsect2>
 460       <title>Path</title>
 461
 462       <para>The file system path specification supports simple
 463       specifier expansion, see below. The path (after expansion) must be
 464       absolute.</para>
 465     </refsect2>
 466
 467     <refsect2>
 468       <title>Mode</title>
 469
 470       <para>The file access mode to use when creating this file or
 471       directory. If omitted or when set to <literal>-</literal>, the
 472       default is used: 0755 for directories, 0644 for all other file
 473       objects.  For <varname>z</varname>, <varname>Z</varname> lines,
 474       if omitted or when set to <literal>-</literal>, the file access
 475       mode will not be modified. This parameter is ignored for
 476       <varname>x</varname>, <varname>r</varname>,
 477       <varname>R</varname>, <varname>L</varname>, <varname>t</varname>,
 478       and <varname>a</varname> lines.</para>
 479
 480       <para>Optionally, if prefixed with <literal>~</literal>, the
 481       access mode is masked based on the already set access bits for
 482       existing file or directories: if the existing file has all
 483       executable bits unset, all executable bits are removed from the
 484       new access mode, too. Similarly, if all read bits are removed
 485       from the old access mode, they will be removed from the new
 486       access mode too, and if all write bits are removed, they will be
 487       removed from the new access mode too. In addition, the
 488       sticky/SUID/SGID bit is removed unless applied to a
 489       directory. This functionality is particularly useful in
 490       conjunction with <varname>Z</varname>.</para>
 491     </refsect2>
 492
 493     <refsect2>
 494       <title>UID, GID</title>
 495
 496       <para>The user and group to use for this file or directory. This may either be a numeric user/group ID or a user or group
 497       name. If omitted or when set to <literal>-</literal>, the user/group ID of the user who invokes <command>systemd-tmpfiles</command> is used.
 498       For <varname>z</varname> and <varname>Z</varname> lines, when omitted or when set to <literal>-</literal>, the file ownership will not be
 499       modified. These parameters are ignored for <varname>x</varname>, <varname>r</varname>, <varname>R</varname>, <varname>L</varname>,
 500       <varname>t</varname>, and <varname>a</varname> lines.</para>
 501     </refsect2>
 502
 503     <refsect2>
 504       <title>Age</title>
 505       <para>The date field, when set, is used to decide what files to
 506       delete when cleaning. If a file or directory is older than the
 507       current time minus the age field, it is deleted. The field
 508       format is a series of integers each followed by one of the
 509       following suffixes for the respective time units:
 510       <constant>s</constant>,
 511       <constant>m</constant> or <constant>min</constant>,
 512       <constant>h</constant>,
 513       <constant>d</constant>,
 514       <constant>w</constant>,
 515       <constant>ms</constant>, and
 516       <constant>us</constant>,
 517       meaning seconds, minutes, hours, days, weeks,
 518       milliseconds, and microseconds, respectively. Full names of the time units can
 519       be used too.
 520       </para>
 521
 522       <para>If multiple integers and units are specified, the time
 523       values are summed. If an integer is given without a unit,
 524       <constant>s</constant> is assumed.
 525       </para>
 526
 527       <para>When the age is set to zero, the files are cleaned
 528       unconditionally.</para>
 529
 530       <para>The age field only applies to lines starting with
 531       <varname>d</varname>, <varname>D</varname>, <varname>e</varname>,
 532       <varname>v</varname>, <varname>q</varname>,
 533       <varname>Q</varname>, <varname>C</varname>, <varname>x</varname>
 534       and <varname>X</varname>. If omitted or set to
 535       <literal>-</literal>, no automatic clean-up is done.</para>
 536
 537       <para>If the age field starts with a tilde character
 538       <literal>~</literal>, the clean-up is only applied to files and
 539       directories one level inside the directory specified, but not
 540       the files and directories immediately inside it.</para>
 541
 542       <para>The age of a file system entry is determined from its last
 543       modification timestamp (mtime), its last access timestamp (atime),
 544       and (except for directories) its last status change timestamp
 545       (ctime). Any of these three (or two) values will prevent cleanup
 546       if it is more recent than the current time minus the age
 547       field.</para>
 548     </refsect2>
 549
 550     <refsect2>
 551       <title>Argument</title>
 552
 553       <para>For <varname>L</varname> lines determines the destination path of the symlink. For <varname>c</varname> and
 554       <varname>b</varname>, determines the major/minor of the device node, with major and minor formatted as integers,
 555       separated by <literal>:</literal>, e.g.  <literal>1:3</literal>. For <varname>f</varname>, <varname>F</varname>,
 556       and <varname>w</varname>, the argument may be used to specify a short string that is written to the file,
 557       suffixed by a newline. For <varname>C</varname>, specifies the source file or directory. For <varname>t</varname>
 558       and <varname>T</varname>, determines extended attributes to be set. For <varname>a</varname> and
 559       <varname>A</varname>, determines ACL attributes to be set. For <varname>h</varname> and <varname>H</varname>,
 560       determines the file attributes to set. Ignored for all other lines.</para>
 561
 562       <para>This field can contain specifiers, see below.</para>
 563     </refsect2>
 564   </refsect1>
 565
 566   <refsect1>
 567     <title>Specifiers</title>
 568
 569     <para>Specifiers can be used in the "path" and "argument" fields.
 570     An unknown or unresolvable specifier is treated as invalid configuration.
 571     The following expansions are understood:</para>
 572       <table>
 573         <title>Specifiers available</title>
 574         <tgroup cols='3' align='left' colsep='1' rowsep='1'>
 575           <colspec colname="spec" />
 576           <colspec colname="mean" />
 577           <colspec colname="detail" />
 578           <thead>
 579             <row>
 580               <entry>Specifier</entry>
 581               <entry>Meaning</entry>
 582               <entry>Details</entry>
 583             </row>
 584           </thead>
 585           <tbody>
 586             <row>
 587               <entry><literal>%b</literal></entry>
 588               <entry>Boot ID</entry>
 589               <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
 590             </row>
 591             <row>
 592               <entry><literal>%C</literal></entry>
 593               <entry>System or user cache directory</entry>
 594               <entry>In <option>--user</option> mode, this is the same as <varname>$XDG_CACHE_HOME</varname>, and <filename>/var/cache</filename> otherwise.</entry>
 595             </row>
 596             <row>
 597               <entry><literal>%h</literal></entry>
 598               <entry>User home directory</entry>
 599               <entry>This is the home directory of the user running the command. In case of the system instance this resolves to <literal>/root</literal>.</entry>
 600             </row>
 601             <row>
 602               <entry><literal>%H</literal></entry>
 603               <entry>Host name</entry>
 604               <entry>The hostname of the running system.</entry>
 605             </row>
 606             <row>
 607               <entry><literal>%L</literal></entry>
 608               <entry>System or user log directory</entry>
 609               <entry>In <option>--user</option> mode, this is the same as <varname>$XDG_CONFIG_HOME</varname> with <filename noindex='true'>/log</filename> appended, and <filename>/var/log</filename> otherwise.</entry>
 610             </row>
 611             <row>
 612               <entry><literal>%m</literal></entry>
 613               <entry>Machine ID</entry>
 614               <entry>The machine ID of the running system, formatted as string. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</entry>
 615             </row>
 616             <row>
 617               <entry><literal>%S</literal></entry>
 618               <entry>System or user state directory</entry>
 619               <entry>In <option>--user</option> mode, this is the same as <varname>$XDG_CONFIG_HOME</varname>, and <filename>/var/lib</filename> otherwise.</entry>
 620             </row>
 621             <row>
 622               <entry><literal>%t</literal></entry>
 623               <entry>System or user runtime directory</entry>
 624               <entry>In <option>--user</option> mode, this is the same <varname>$XDG_RUNTIME_DIR</varname>, and <filename>/run</filename> otherwise.</entry>
 625             </row>
 626             <row>
 627               <entry><literal>%T</literal></entry>
 628               <entry>Directory for temporary files</entry>
 629               <entry>This is either <filename>/tmp</filename> or the path <literal>$TMPDIR</literal>, <literal>$TEMP</literal> or <literal>$TMP</literal> are set to.</entry>
 630             </row>
 631             <row>
 632               <entry><literal>%g</literal></entry>
 633               <entry>User group</entry>
 634               <entry>This is the name of the group running the command. In case of the system instance this resolves to <literal>root</literal>.</entry>
 635             </row>
 636             <row>
 637               <entry><literal>%G</literal></entry>
 638               <entry>User GID</entry>
 639               <entry>This is the numeric GID of the group running the command. In case of the system instance this resolves to <constant>0</constant>.</entry>
 640             </row>
 641             <row>
 642               <entry><literal>%u</literal></entry>
 643               <entry>User name</entry>
 644               <entry>This is the name of the user running the command. In case of the system instance this resolves to <literal>root</literal>.</entry>
 645             </row>
 646             <row>
 647               <entry><literal>%U</literal></entry>
 648               <entry>User UID</entry>
 649               <entry>This is the numeric UID of the user running the command. In case of the system instance this resolves to <constant>0</constant>.</entry>
 650             </row>
 651             <row>
 652               <entry><literal>%v</literal></entry>
 653               <entry>Kernel release</entry>
 654               <entry>Identical to <command>uname -r</command> output.</entry>
 655             </row>
 656             <row>
 657               <entry><literal>%V</literal></entry>
 658               <entry>Directory for larger and persistent temporary files</entry>
 659               <entry>This is either <filename>/var/tmp</filename> or the path <literal>$TMPDIR</literal>, <literal>$TEMP</literal> or <literal>$TMP</literal> are set to.</entry>
 660             </row>
 661             <row>
 662               <entry><literal>%%</literal></entry>
 663               <entry>Escaped <literal>%</literal></entry>
 664               <entry>Single percent sign.</entry>
 665             </row>
 666           </tbody>
 667         </tgroup>
 668       </table>
 669   </refsect1>
 670
 671   <refsect1>
 672     <title>Examples</title>
 673     <example>
 674       <title>Create directories with specific mode and ownership</title>
 675       <para>
 676       <citerefentry project='die-net'><refentrytitle>screen</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 677       needs two directories created at boot with specific modes and ownership:</para>
 678
 679       <programlisting># /usr/lib/tmpfiles.d/screen.conf
 680 d /run/screens  1777 root screen 10d
 681 d /run/uscreens 0755 root screen 10d12h
 682 </programlisting>
 683
 684       <para>Contents of <filename>/run/screens</filename> and /run/uscreens will
 685       be cleaned up after 10 and 10½ days, respectively.</para>
 686     </example>
 687
 688     <example>
 689       <title>Create a directory with a SMACK attribute</title>
 690       <programlisting>D /run/cups - - - -
 691 t /run/cups - - - - security.SMACK64=printing user.attr-with-spaces="foo bar"
 692       </programlisting>
 693
 694       <para>The directory will be owned by root and have default mode. Its contents are
 695       not subject to time based cleanup, but will be obliterated when
 696       <command>systemd-tmpfiles --remove</command> runs.</para>
 697     </example>
 698
 699     <example>
 700       <title>Create a directory and prevent its contents from cleanup</title>
 701       <para>
 702       <citerefentry project='die-net'><refentrytitle>abrt</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 703       needs a directory created at boot with specific mode and ownership and its content
 704       should be preserved from the automatic cleanup applied to the contents of
 705       <filename>/var/tmp</filename>:</para>
 706
 707       <programlisting># /usr/lib/tmpfiles.d/tmp.conf
 708 d /var/tmp 1777 root root 30d
 709 </programlisting>
 710
 711       <programlisting># /usr/lib/tmpfiles.d/abrt.conf
 712 d /var/tmp/abrt 0755 abrt abrt -
 713 </programlisting>
 714     </example>
 715
 716     <example>
 717       <title>Apply clean up during boot and based on time</title>
 718
 719       <programlisting># /usr/lib/tmpfiles.d/dnf.conf
 720 r! /var/cache/dnf/*/*/download_lock.pid
 721 r! /var/cache/dnf/*/*/metadata_lock.pid
 722 r! /var/lib/dnf/rpmdb_lock.pid
 723 e  /var/cache/dnf/ - - - 30d
 724 </programlisting>
 725
 726      <para>The lock files will be removed during boot. Any files and directories in
 727      <filename>/var/cache/dnf/</filename> will be removed after they have not been
 728      accessed in 30 days.</para>
 729     </example>
 730
 731     <example>
 732       <title>Empty the contents of a cache directory on boot</title>
 733
 734       <programlisting># /usr/lib/tmpfiles.d/krb5rcache.conf
 735 e! /var/cache/krb5rcache - - - 0
 736 </programlisting>
 737
 738       <para>Any files and subdirectories in <filename>/var/cache/krb5rcache/</filename>
 739       will be removed on boot. The directory will not be created.
 740       </para>
 741     </example>
 742   </refsect1>
 743
 744   <refsect1>
 745     <title>See Also</title>
 746     <para>
 747       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 748       <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 749       <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 750       <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 751       <citerefentry project='man-pages'><refentrytitle>attr</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 752       <citerefentry project='man-pages'><refentrytitle>getfattr</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 753       <citerefentry project='man-pages'><refentrytitle>setfattr</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 754       <citerefentry project='man-pages'><refentrytitle>setfacl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 755       <citerefentry project='man-pages'><refentrytitle>getfacl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 756       <citerefentry project='man-pages'><refentrytitle>chattr</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 757       <citerefentry project='die-net'><refentrytitle>btrfs-subvolume</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 758       <citerefentry project='die-net'><refentrytitle>btrfs-qgroup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 759     </para>
 760   </refsect1>
 761
 762 </refentry>