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">
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   5   This file is part of systemd.
   6
   7   Copyright 2010 Brandon Philips
   8
   9   systemd is free software; you can redistribute it and/or modify it
  10   under the terms of the GNU Lesser General Public License as published by
  11   the Free Software Foundation; either version 2.1 of the License, or
  12   (at your option) any later version.
  13
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  17   Lesser General Public License for more details.
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  20   along with systemd; If not, see <http://www.gnu.org/licenses/>.
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  22 <refentry id="tmpfiles.d">
  23
  24         <refentryinfo>
  25                 <title>tmpfiles.d</title>
  26                 <productname>systemd</productname>
  27
  28                 <authorgroup>
  29                         <author>
  30                                 <contrib>Documentation</contrib>
  31                                 <firstname>Brandon</firstname>
  32                                 <surname>Philips</surname>
  33                                 <email>brandon@ifup.org</email>
  34                         </author>
  35                 </authorgroup>
  36         </refentryinfo>
  37
  38         <refmeta>
  39                 <refentrytitle>tmpfiles.d</refentrytitle>
  40                 <manvolnum>5</manvolnum>
  41         </refmeta>
  42
  43         <refnamediv>
  44                 <refname>tmpfiles.d</refname>
  45                 <refpurpose>Configuration for creation, deletion and
  46                 cleaning of volatile and temporary files</refpurpose>
  47         </refnamediv>
  48
  49         <refsynopsisdiv>
  50                 <para><filename>/etc/tmpfiles.d/*.conf</filename></para>
  51                 <para><filename>/run/tmpfiles.d/*.conf</filename></para>
  52                 <para><filename>/usr/lib/tmpfiles.d/*.conf</filename></para>
  53         </refsynopsisdiv>
  54
  55         <refsect1>
  56                 <title>Description</title>
  57
  58                 <para><command>systemd-tmpfiles</command> uses the
  59                 configuration files from the above directories to describe the
  60                 creation, cleaning and removal of volatile and
  61                 temporary files and directories which usually reside
  62                 in directories such as <filename>/run</filename>
  63                 or <filename>/tmp</filename>.</para>
  64
  65                 <para>Volatile and temporary files and directories are
  66                 those located in <filename>/run</filename> (and its
  67                 alias <filename>/var/run</filename>),
  68                 <filename>/tmp</filename>,
  69                 <filename>/var/tmp</filename>, the API file systems
  70                 such as <filename>/sys</filename> or
  71                 <filename>/proc</filename>, as well as some other
  72                 directories below <filename>/var</filename>.</para>
  73
  74                 <para>System daemons frequently require private
  75                 runtime directories below <filename>/run</filename> to
  76                 place communication sockets and similar in. For these
  77                 consider declaring them in their unit files using
  78                 <varname>RuntimeDirectory=</varname>
  79                 (see <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details),
  80                 if this is feasible.</para>
  81         </refsect1>
  82
  83         <refsect1>
  84                 <title>Configuration Format</title>
  85
  86                 <para>Each configuration file shall be named in the
  87                 style of
  88                 <filename><replaceable>package</replaceable>.conf</filename>
  89                 or
  90                 <filename><replaceable>package</replaceable>-<replaceable>part</replaceable>.conf</filename>.
  91                 The second variant should be used when it is desirable
  92                 to make it easy to override just this part of
  93                 configuration.</para>
  94
  95                 <para>Files in <filename>/etc/tmpfiles.d</filename>
  96                 override files with the same name in
  97                 <filename>/usr/lib/tmpfiles.d</filename> and
  98                 <filename>/run/tmpfiles.d</filename>. Files in
  99                 <filename>/run/tmpfiles.d</filename> override files
 100                 with the same name in
 101                 <filename>/usr/lib/tmpfiles.d</filename>. Packages
 102                 should install their configuration files in
 103                 <filename>/usr/lib/tmpfiles.d</filename>. Files in
 104                 <filename>/etc/tmpfiles.d</filename> are reserved for
 105                 the local administrator, who may use this logic to
 106                 override the configuration files installed by vendor
 107                 packages. All configuration files are sorted by their
 108                 filename in lexicographic order, regardless of which
 109                 of the directories they reside in. If multiple files
 110                 specify the same path, the entry in the file with the
 111                 lexicographically earliest name will be applied, all
 112                 all other conflicting entries logged as errors.</para>
 113
 114                 <para>If the administrator wants to disable a
 115                 configuration file supplied by the vendor, the
 116                 recommended way is to place a symlink to
 117                 <filename>/dev/null</filename> in
 118                 <filename>/etc/tmpfiles.d/</filename> bearing the
 119                 same filename.</para>
 120
 121                 <para>The configuration format is one line per path
 122                 containing type, path, mode, ownership, age, and argument
 123                 fields:</para>
 124
 125                 <programlisting>#Type Path        Mode UID  GID  Age Argument
 126 d    /run/user   0755 root root 10d -
 127 L    /tmp/foobar -    -    -    -   /dev/null</programlisting>
 128
 129                 <refsect2>
 130                         <title>Type</title>
 131
 132                         <para>The type consists of a single letter and
 133                         optionally an exclamation mark.</para>
 134
 135                         <para>The following line types are understood:</para>
 136
 137                         <variablelist>
 138                                 <varlistentry>
 139                                         <term><varname>f</varname></term>
 140                                         <listitem><para>Create a file if it does not exist yet. If the argument parameter is given, it will be written to the file.</para></listitem>
 141                                 </varlistentry>
 142
 143                                 <varlistentry>
 144                                         <term><varname>F</varname></term>
 145                                         <listitem><para>Create or truncate a file. If the argument parameter is given, it will be written to the file.</para></listitem>
 146                                 </varlistentry>
 147
 148                                 <varlistentry>
 149                                         <term><varname>w</varname></term>
 150                                         <listitem><para>Write the argument parameter to a file, if the file exists.
 151                                             Lines of this type accept shell-style globs in place of normal path
 152                                             names. The argument parameter will be written without a trailing
 153                                             newline. C-style backslash escapes are interpreted.</para></listitem>
 154                                 </varlistentry>
 155
 156                                 <varlistentry>
 157                                         <term><varname>d</varname></term>
 158                                         <listitem><para>Create a directory if it does not exist yet.</para></listitem>
 159                                 </varlistentry>
 160
 161                                 <varlistentry>
 162                                         <term><varname>D</varname></term>
 163                                         <listitem><para>Create or empty a directory.</para></listitem>
 164                                 </varlistentry>
 165
 166                                 <varlistentry>
 167                                         <term><varname>p</varname></term>
 168                                         <listitem><para>Create a named pipe (FIFO) if it does not exist yet.</para></listitem>
 169                                 </varlistentry>
 170
 171                                 <varlistentry>
 172                                         <term><varname>L</varname></term>
 173                                         <listitem><para>Create a symlink if it does not exist yet.</para></listitem>
 174                                 </varlistentry>
 175
 176                                 <varlistentry>
 177                                         <term><varname>c</varname></term>
 178                                         <listitem><para>Create a character device node if it does not exist yet.</para></listitem>
 179                                 </varlistentry>
 180
 181                                 <varlistentry>
 182                                         <term><varname>b</varname></term>
 183                                         <listitem><para>Create a block device node if it does not exist yet.</para></listitem>
 184                                 </varlistentry>
 185
 186                                 <varlistentry>
 187                                         <term><varname>m</varname></term>
 188                                         <listitem><para>If the
 189                                         specified file path exists,
 190                                         adjust its access mode, group
 191                                         and user to the specified
 192                                         values and reset the SELinux
 193                                         security context. If it does not exist, do
 194                                         nothing.</para></listitem>
 195                                 </varlistentry>
 196
 197                                 <varlistentry>
 198                                         <term><varname>x</varname></term>
 199                                         <listitem><para>Ignore a path
 200                                         during cleaning. Use this type
 201                                         to exclude paths from clean-up
 202                                         as controlled with the Age
 203                                         parameter. Note that lines of
 204                                         this type do not influence the
 205                                         effect of <varname>r</varname>
 206                                         or <varname>R</varname> lines.
 207                                         Lines of this type accept
 208                                         shell-style globs in place of
 209                                         normal path names.
 210                                         </para></listitem>
 211                                 </varlistentry>
 212
 213                                 <varlistentry>
 214                                         <term><varname>X</varname></term>
 215                                         <listitem><para>Ignore a path
 216                                         during cleaning. Use this type
 217                                         to exclude paths from clean-up
 218                                         as controlled with the Age
 219                                         parameter. Unlike
 220                                         <varname>x</varname>, this
 221                                         parameter will not exclude the
 222                                         content if path is a
 223                                         directory, but only directory
 224                                         itself. Note that lines of
 225                                         this type do not influence the
 226                                         effect of <varname>r</varname>
 227                                         or <varname>R</varname> lines.
 228                                         Lines of this type accept
 229                                         shell-style globs in place of
 230                                         normal path names.
 231                                         </para></listitem>
 232                                 </varlistentry>
 233
 234                                 <varlistentry>
 235                                         <term><varname>r</varname></term>
 236                                         <listitem><para>Remove a file
 237                                         or directory if it exists.
 238                                         This may not be used to remove
 239                                         non-empty directories, use
 240                                         <varname>R</varname> for that.
 241                                         Lines of this type accept
 242                                         shell-style globs in place of
 243                                         normal path
 244                                         names.</para></listitem>
 245                                 </varlistentry>
 246
 247                                 <varlistentry>
 248                                         <term><varname>R</varname></term>
 249                                         <listitem><para>Recursively
 250                                         remove a path and all its
 251                                         subdirectories (if it is a
 252                                         directory). Lines of this type
 253                                         accept shell-style globs in
 254                                         place of normal path
 255                                         names.</para></listitem>
 256                                 </varlistentry>
 257
 258                                 <varlistentry>
 259                                         <term><varname>z</varname></term>
 260                                         <listitem><para>Restore
 261                                         SELinux security context
 262                                         and set ownership and access
 263                                         mode of a file or directory if
 264                                         it exists.  Lines of this type
 265                                         accept shell-style globs in
 266                                         place of normal path names.
 267                                         </para></listitem>
 268                                 </varlistentry>
 269
 270                                 <varlistentry>
 271                                         <term><varname>Z</varname></term>
 272                                         <listitem><para>Recursively
 273                                         restore SELinux security
 274                                         context and set
 275                                         ownership and access mode of a
 276                                         path and all its
 277                                         subdirectories (if it is a
 278                                         directory). Lines of this type
 279                                         accept shell-style globs in
 280                                         place of normal path
 281                                         names.</para></listitem>
 282                                 </varlistentry>
 283                         </variablelist>
 284
 285                         <para>If the exclamation mark is used, this
 286                         line is only safe of execute during boot, and
 287                         can break a running system. Lines without the
 288                         exclamation mark are presumed to be safe to
 289                         execute at any time, e.g. on package upgrades.
 290                         <command>systemd-tmpfiles</command> will
 291                         execute line with an exclamation mark only if
 292                         option <option>--boot</option> is given.
 293                         </para>
 294
 295                         <para>For example:
 296                         <programlisting># Make sure these are created by default so that nobody else can
 297 d /tmp/.X11-unix 1777 root root 10d
 298
 299 # Unlink the X11 lock files
 300 r! /tmp/.X[0-9]*-lock</programlisting>
 301                         The second line in contrast to the first one
 302                         would break a running system, and will only be
 303                         executed with <option>--boot</option>.</para>
 304                 </refsect2>
 305
 306                 <refsect2>
 307                         <title>Path</title>
 308
 309                         <para>The file system path specification supports simple specifier
 310                         expansion. The following expansions are
 311                         understood:</para>
 312
 313                         <table>
 314                                 <title>Specifiers available</title>
 315                                 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
 316                                         <colspec colname="spec" />
 317                                         <colspec colname="mean" />
 318                                         <colspec colname="detail" />
 319                                         <thead>
 320                                                 <row>
 321                                                         <entry>Specifier</entry>
 322                                                         <entry>Meaning</entry>
 323                                                         <entry>Details</entry>
 324                                                 </row>
 325                                         </thead>
 326                                         <tbody>
 327                                                 <row>
 328                                                         <entry><literal>%m</literal></entry>
 329                                                         <entry>Machine ID</entry>
 330                                                         <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>
 331                                                 </row>
 332                                                 <row>
 333                                                         <entry><literal>%b</literal></entry>
 334                                                         <entry>Boot ID</entry>
 335                                                         <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
 336                                                 </row>
 337                                                 <row>
 338                                                         <entry><literal>%H</literal></entry>
 339                                                         <entry>Host name</entry>
 340                                                         <entry>The hostname of the running system.</entry>
 341                                                 </row>
 342                                                 <row>
 343                                                         <entry><literal>%v</literal></entry>
 344                                                         <entry>Kernel release</entry>
 345                                                         <entry>Identical to <command>uname -r</command> output.</entry>
 346                                                 </row>
 347                                                 <row>
 348                                                         <entry><literal>%%</literal></entry>
 349                                                         <entry>Escaped %</entry>
 350                                                         <entry>Single percent sign.</entry>
 351                                                 </row>
 352                                         </tbody>
 353                                 </tgroup>
 354                         </table>
 355                 </refsect2>
 356
 357                 <refsect2>
 358                         <title>Mode</title>
 359
 360                         <para>The file access mode to use when
 361                         creating this file or directory. If omitted or
 362                         when set to -, the default is used: 0755 for
 363                         directories, 0644 for all other file objects.
 364                         For <varname>z</varname>, <varname>Z</varname>
 365                         lines, if omitted or when set to
 366                         <literal>-</literal>, the file access mode
 367                         will not be modified. This parameter is
 368                         ignored for <varname>x</varname>,
 369                         <varname>r</varname>, <varname>R</varname>,
 370                         <varname>L</varname> lines.</para>
 371                 </refsect2>
 372
 373                 <refsect2>
 374                         <title>UID, GID</title>
 375
 376                         <para>The user and group to use for this file
 377                         or directory. This may either be a numeric
 378                         user/group ID or a user or group name. If
 379                         omitted or when set to <literal>-</literal>,
 380                         the default 0 (root) is used. For
 381                         <varname>z</varname>, <varname>Z</varname>
 382                         lines, when omitted or when set to -, the file
 383                         ownership will not be modified. These
 384                         parameters are ignored for
 385                         <varname>x</varname>, <varname>r</varname>,
 386                         <varname>R</varname>, <varname>L</varname>
 387                         lines.</para>
 388                 </refsect2>
 389
 390                 <refsect2>
 391                         <title>Age</title>
 392                         <para>The date field, when set, is used to
 393                         decide what files to delete when cleaning. If
 394                         a file or directory is older than the current
 395                         time minus the age field, it is deleted. The
 396                         field format is a series of integers each
 397                         followed by one of the following
 398                         postfixes for the respective time units:</para>
 399
 400                         <variablelist>
 401                                 <varlistentry>
 402                                 <term><varname>s</varname></term>
 403                                 <term><varname>min</varname></term>
 404                                 <term><varname>h</varname></term>
 405                                 <term><varname>d</varname></term>
 406                                 <term><varname>w</varname></term>
 407                                 <term><varname>ms</varname></term>
 408                                 <term><varname>m</varname></term>
 409                                 <term><varname>us</varname></term></varlistentry>
 410                         </variablelist>
 411
 412                         <para>If multiple integers and units are specified, the time
 413                         values are summed up. If an integer is given without a unit,
 414                         s is assumed.
 415                         </para>
 416
 417                         <para>When the age is set to zero, the files are cleaned
 418                         unconditionally.</para>
 419
 420                         <para>The age field only applies to lines
 421                         starting with <varname>d</varname>,
 422                         <varname>D</varname>, and
 423                         <varname>x</varname>. If omitted or set to
 424                         <literal>-</literal>, no automatic clean-up is
 425                         done.</para>
 426
 427                         <para>If the age field starts with a tilde
 428                         character <literal>~</literal>, the clean-up
 429                         is only applied to files and directories one
 430                         level inside the directory specified, but not
 431                         the files and directories immediately inside
 432                         it.</para>
 433                 </refsect2>
 434
 435                 <refsect2>
 436                         <title>Argument</title>
 437
 438                         <para>For <varname>L</varname> lines
 439                         determines the destination path of the
 440                         symlink. For <varname>c</varname>,
 441                         <varname>b</varname> determines the
 442                         major/minor of the device node, with major and
 443                         minor formatted as integers, separated by
 444                         <literal>:</literal>, e.g.
 445                         <literal>1:3</literal>. For
 446                         <varname>f</varname>, <varname>F</varname>,
 447                         and <varname>w</varname> may be used to
 448                         specify a short string that is written to the
 449                         file, suffixed by a newline. Ignored for all
 450                         other lines.</para>
 451                 </refsect2>
 452
 453         </refsect1>
 454
 455         <refsect1>
 456                 <title>Example</title>
 457                 <example>
 458                         <title>/etc/tmpfiles.d/screen.conf example</title>
 459                         <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
 460
 461                         <programlisting>d /run/screens  1777 root root 10d
 462 d /run/uscreens 0755 root root 10d12h</programlisting>
 463                 </example>
 464                 <example>
 465                         <title>/etc/tmpfiles.d/abrt.conf example</title>
 466                         <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
 467
 468                         <programlisting>d /var/tmp/abrt 0755 abrt abrt
 469 x /var/tmp/abrt/*</programlisting>
 470                 </example>
 471         </refsect1>
 472
 473         <refsect1>
 474                 <title>See Also</title>
 475                 <para>
 476                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 477                         <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 478                         <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 479                         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 480                 </para>
 481         </refsect1>
 482
 483 </refentry>