man/tmpfiles.d.xml

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   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
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  10   under the terms of the GNU Lesser General Public License as published by
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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         </refsect1>
  65
  66         <refsect1>
  67                 <title>Configuration Format</title>
  68
  69                 <para>Each configuration file shall be named in the
  70                 style of <filename>&lt;package&gt;.conf</filename>.
  71                 Files in <filename>/etc/</filename> override files
  72                 with the same name in <filename>/usr/lib/</filename>
  73                 and <filename>/run/</filename>.  Files in
  74                 <filename>/run/</filename> override files with the same
  75                 name in <filename>/usr/lib/</filename>. Packages
  76                 should install their configuration files in
  77                 <filename>/usr/lib/</filename>. Files in
  78                 <filename>/etc/</filename> are reserved for the local
  79                 administrator, who may use this logic to override the
  80                 configuration files installed by vendor packages. All
  81                 configuration files are sorted by their filename in
  82                 lexicographic order, regardless in which of the
  83                 directories they reside. If multiple files specify the
  84                 same path, the entry in the file with the lexicographically
  85                 earliest name will be applied, all all other conflicting
  86                 entries logged as errors.</para>
  87
  88                 <para>If the administrator wants to disable a
  89                 configuration file supplied by the vendor, the
  90                 recommended way is to place a symlink to
  91                 <filename>/dev/null</filename> in
  92                 <filename>/etc/tmpfiles.d/</filename> bearing the
  93                 same filename.</para>
  94
  95                 <para>The configuration format is one line per path
  96                 containing action, path, mode, ownership, age and argument
  97                 fields:</para>
  98
  99                 <programlisting>Type Path        Mode UID  GID  Age Argument
 100 d    /run/user   0755 root root 10d -
 101 L    /tmp/foobar -    -    -    -   /dev/null</programlisting>
 102
 103
 104                 <refsect2>
 105                         <title>Type</title>
 106
 107                         <para>The following line types are understood:</para>
 108
 109                         <variablelist>
 110                                 <varlistentry>
 111                                         <term><varname>f</varname></term>
 112                                         <listitem><para>Create a file if it does not exist yet (optionally writing a short string into it, if the argument parameter is passed)</para></listitem>
 113                                 </varlistentry>
 114
 115                                 <varlistentry>
 116                                         <term><varname>F</varname></term>
 117                                         <listitem><para>Create or truncate a file (optionally writing a short string into it, if the argument parameter is passed)</para></listitem>
 118                                 </varlistentry>
 119
 120                                 <varlistentry>
 121                                         <term><varname>w</varname></term>
 122                                         <listitem><para>Write the argument parameter to a file, if the file exists.
 123                                             Lines of this type accept shell-style globs in place of normal path
 124                                             names. The argument parameter will be written without a trailing
 125                                             newline. C-style backslash escapes are interpreted.</para></listitem>
 126                                 </varlistentry>
 127
 128                                 <varlistentry>
 129                                         <term><varname>d</varname></term>
 130                                         <listitem><para>Create a directory if it does not exist yet</para></listitem>
 131                                 </varlistentry>
 132
 133                                 <varlistentry>
 134                                         <term><varname>D</varname></term>
 135                                         <listitem><para>Create or empty a directory</para></listitem>
 136                                 </varlistentry>
 137
 138                                 <varlistentry>
 139                                         <term><varname>p</varname></term>
 140                                         <listitem><para>Create a named pipe (FIFO) if it does not exist yet</para></listitem>
 141                                 </varlistentry>
 142
 143                                 <varlistentry>
 144                                         <term><varname>L</varname></term>
 145                                         <listitem><para>Create a symlink if it does not exist yet</para></listitem>
 146                                 </varlistentry>
 147
 148                                 <varlistentry>
 149                                         <term><varname>c</varname></term>
 150                                         <listitem><para>Create a character device node if it does not exist yet</para></listitem>
 151                                 </varlistentry>
 152
 153                                 <varlistentry>
 154                                         <term><varname>b</varname></term>
 155                                         <listitem><para>Create a block device node if it does not exist yet</para></listitem>
 156                                 </varlistentry>
 157
 158                                 <varlistentry>
 159                                         <term><varname>x</varname></term>
 160                                         <listitem><para>Ignore a path
 161                                         during cleaning. Use this type
 162                                         to exclude paths from clean-up
 163                                         as controlled with the Age
 164                                         parameter. Note that lines of
 165                                         this type do not influence the
 166                                         effect of r or R lines. Lines
 167                                         of this type accept
 168                                         shell-style globs in place of
 169                                         normal path
 170                                         names.</para></listitem>
 171                                 </varlistentry>
 172
 173                                 <varlistentry>
 174                                         <term><varname>X</varname></term>
 175                                         <listitem><para>Ignore a path
 176                                         during cleanup. Use this type
 177                                         to prevent path removal as
 178                                         controlled with the Age parameter.
 179                                         Note that if path is a directory,
 180                                         content of a directory is not
 181                                         excluded from clean-up, only
 182                                         directory itself. Lines of this
 183                                         type accept shell-style globs
 184                                         in place of normal path
 185                                         names.</para></listitem>
 186                                 </varlistentry>
 187
 188                                 <varlistentry>
 189                                         <term><varname>r</varname></term>
 190                                         <listitem><para>Remove a file
 191                                         or directory if it
 192                                         exists. This may not be used
 193                                         to remove non-empty
 194                                         directories, use R for
 195                                         that. Lines of this type
 196                                         accept shell-style globs in
 197                                         place of normal path
 198                                         names.</para></listitem>
 199                                 </varlistentry>
 200
 201                                 <varlistentry>
 202                                         <term><varname>R</varname></term>
 203                                         <listitem><para>Recursively
 204                                         remove a path and all its
 205                                         subdirectories (if it is a
 206                                         directory). Lines of this type
 207                                         accept shell-style globs in
 208                                         place of normal path
 209                                         names.</para></listitem>
 210                                 </varlistentry>
 211
 212                                 <varlistentry>
 213                                         <term><varname>z</varname></term>
 214                                         <listitem><para>Restore
 215                                         SELinux security context label
 216                                         and set ownership and access
 217                                         mode of a file or directory if
 218                                         it exists.  Lines of this type
 219                                         accept shell-style globs in
 220                                         place of normal path names.
 221                                         </para></listitem>
 222                                 </varlistentry>
 223
 224                                 <varlistentry>
 225                                         <term><varname>Z</varname></term>
 226                                         <listitem><para>Recursively
 227                                         restore SELinux security
 228                                         context label and set
 229                                         ownership and access mode of a
 230                                         path and all its
 231                                         subdirectories (if it is a
 232                                         directory). Lines of this type
 233                                         accept shell-style globs in
 234                                         place of normal path
 235                                         names.</para></listitem>
 236                                 </varlistentry>
 237                         </variablelist>
 238                 </refsect2>
 239
 240                 <refsect2>
 241                         <title>Path</title>
 242
 243                         <para>The file system path specification supports simple specifier
 244                         expansion. The following expansions are
 245                         understood:</para>
 246
 247                         <table>
 248                                 <title>Specifiers available</title>
 249                                 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
 250                                         <colspec colname="spec" />
 251                                         <colspec colname="mean" />
 252                                         <colspec colname="detail" />
 253                                         <thead>
 254                                                 <row>
 255                                                         <entry>Specifier</entry>
 256                                                         <entry>Meaning</entry>
 257                                                         <entry>Details</entry>
 258                                                 </row>
 259                                         </thead>
 260                                         <tbody>
 261                                                 <row>
 262                                                         <entry><literal>%m</literal></entry>
 263                                                         <entry>Machine ID</entry>
 264                                                         <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>
 265                                                 </row>
 266                                                 <row>
 267                                                         <entry><literal>%b</literal></entry>
 268                                                         <entry>Boot ID</entry>
 269                                                         <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
 270                                                 </row>
 271                                                 <row>
 272                                                         <entry><literal>%H</literal></entry>
 273                                                         <entry>Host name</entry>
 274                                                         <entry>The hostname of the running system.</entry>
 275                                                 </row>
 276                                                 <row>
 277                                                         <entry><literal>%v</literal></entry>
 278                                                         <entry>Kernel release</entry>
 279                                                         <entry>Identical to <command>uname -r</command> output.</entry>
 280                                                 </row>
 281                                                 <row>
 282                                                         <entry><literal>%%</literal></entry>
 283                                                         <entry>Escaped %</entry>
 284                                                         <entry>Single percent sign.</entry>
 285                                                 </row>
 286                                         </tbody>
 287                                 </tgroup>
 288                         </table>
 289                 </refsect2>
 290
 291                 <refsect2>
 292                         <title>Mode</title>
 293
 294                         <para>The file access mode to use when
 295                         creating this file or directory. If omitted or
 296                         when set to -, the default is used: 0755 for
 297                         directories, 0644 for all other file
 298                         objects. For z, Z lines, if omitted or when set
 299                         to -, the file access mode will not be
 300                         modified. This parameter is ignored for x, r,
 301                         R, L lines.</para>
 302                 </refsect2>
 303
 304                 <refsect2>
 305                         <title>UID, GID</title>
 306
 307                         <para>The user and group to use for this file
 308                         or directory. This may either be a numeric
 309                         user/group ID or a user or group name. If
 310                         omitted or when set to -, the default 0 (root)
 311                         is used. For z, Z lines, when omitted or when set to -,
 312                         the file ownership will not be modified.
 313                         These parameters are ignored for x, r, R, L lines.</para>
 314                 </refsect2>
 315
 316                 <refsect2>
 317                         <title>Age</title>
 318                         <para>The date field, when set, is used to
 319                         decide what files to delete when cleaning. If
 320                         a file or directory is older than the current
 321                         time minus the age field, it is deleted. The
 322                         field format is a series of integers each
 323                         followed by one of the following
 324                         postfixes for the respective time units:</para>
 325
 326                         <variablelist>
 327                                 <varlistentry>
 328                                 <term><varname>s</varname></term>
 329                                 <term><varname>min</varname></term>
 330                                 <term><varname>h</varname></term>
 331                                 <term><varname>d</varname></term>
 332                                 <term><varname>w</varname></term>
 333                                 <term><varname>ms</varname></term>
 334                                 <term><varname>m</varname></term>
 335                                 <term><varname>us</varname></term></varlistentry>
 336                         </variablelist>
 337
 338                         <para>If multiple integers and units are specified, the time
 339                         values are summed up. If an integer is given without a unit,
 340                         s is assumed.
 341                         </para>
 342
 343                         <para>When the age is set to zero, the files are cleaned
 344                         unconditionally.</para>
 345
 346                         <para>The age field only applies to lines starting with
 347                         d, D and x. If omitted or set to -, no automatic clean-up
 348                         is done.</para>
 349
 350                         <para>If the age field starts with a tilde
 351                         character (~), the clean-up is only applied to
 352                         files and directories one level inside the
 353                         directory specified, but not the files and
 354                         directories immediately inside it.</para>
 355                 </refsect2>
 356
 357                 <refsect2>
 358                         <title>Argument</title>
 359
 360                         <para>For L lines determines the destination
 361                         path of the symlink. For c, b determines the
 362                         major/minor of the device node, with major and
 363                         minor formatted as integers, separated by :,
 364                         e.g. "1:3". For f, F, w may be used to specify
 365                         a short string that is written to the file,
 366                         suffixed by a newline. Ignored for all other
 367                         lines.</para>
 368                 </refsect2>
 369
 370         </refsect1>
 371
 372         <refsect1>
 373                 <title>Example</title>
 374                 <example>
 375                         <title>/etc/tmpfiles.d/screen.conf example</title>
 376                         <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
 377
 378                         <programlisting>d /var/run/screens  1777 root root 10d
 379 d /var/run/uscreens 0755 root root 10d12h</programlisting>
 380                 </example>
 381                 <example>
 382                         <title>/etc/tmpfiles.d/abrt.conf example</title>
 383                         <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
 384
 385                         <programlisting>d /var/tmp/abrt 0755 abrt abrt
 386 x /var/tmp/abrt/*</programlisting>
 387                 </example>
 388         </refsect1>
 389
 390         <refsect1>
 391                 <title>See Also</title>
 392                 <para>
 393                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 394                         <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 395                         <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 396                 </para>
 397         </refsect1>
 398
 399 </refentry>