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>m</varname></term>
 160                                         <listitem><para>If the
 161                                         specified file path exists
 162                                         adjust its access mode, group
 163                                         and user to the specified
 164                                         values and reset the SELinux
 165                                         label. If it doesn't exist do
 166                                         nothing.</para></listitem>
 167                                 </varlistentry>
 168
 169                                 <varlistentry>
 170                                         <term><varname>x</varname></term>
 171                                         <listitem><para>Ignore a path
 172                                         during cleaning. Use this type
 173                                         to exclude paths from clean-up
 174                                         as controlled with the Age
 175                                         parameter. Note that lines of
 176                                         this type do not influence the
 177                                         effect of r or R lines. Lines
 178                                         of this type accept
 179                                         shell-style globs in place of
 180                                         normal path
 181                                         names.</para></listitem>
 182                                 </varlistentry>
 183
 184                                 <varlistentry>
 185                                         <term><varname>X</varname></term>
 186                                         <listitem><para>Ignore a path
 187                                         during cleanup. Use this type
 188                                         to prevent path removal as
 189                                         controlled with the Age parameter.
 190                                         Note that if path is a directory,
 191                                         content of a directory is not
 192                                         excluded from clean-up, only
 193                                         directory itself. Lines of this
 194                                         type accept shell-style globs
 195                                         in place of normal path
 196                                         names.</para></listitem>
 197                                 </varlistentry>
 198
 199                                 <varlistentry>
 200                                         <term><varname>r</varname></term>
 201                                         <listitem><para>Remove a file
 202                                         or directory if it
 203                                         exists. This may not be used
 204                                         to remove non-empty
 205                                         directories, use R for
 206                                         that. 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>R</varname></term>
 214                                         <listitem><para>Recursively
 215                                         remove a path and all its
 216                                         subdirectories (if it is a
 217                                         directory). Lines of this type
 218                                         accept shell-style globs in
 219                                         place of normal path
 220                                         names.</para></listitem>
 221                                 </varlistentry>
 222
 223                                 <varlistentry>
 224                                         <term><varname>z</varname></term>
 225                                         <listitem><para>Restore
 226                                         SELinux security context label
 227                                         and set ownership and access
 228                                         mode of a file or directory if
 229                                         it exists.  Lines of this type
 230                                         accept shell-style globs in
 231                                         place of normal path names.
 232                                         </para></listitem>
 233                                 </varlistentry>
 234
 235                                 <varlistentry>
 236                                         <term><varname>Z</varname></term>
 237                                         <listitem><para>Recursively
 238                                         restore SELinux security
 239                                         context label and set
 240                                         ownership and access mode of a
 241                                         path and all its
 242                                         subdirectories (if it is a
 243                                         directory). Lines of this type
 244                                         accept shell-style globs in
 245                                         place of normal path
 246                                         names.</para></listitem>
 247                                 </varlistentry>
 248                         </variablelist>
 249                 </refsect2>
 250
 251                 <refsect2>
 252                         <title>Path</title>
 253
 254                         <para>The file system path specification supports simple specifier
 255                         expansion. The following expansions are
 256                         understood:</para>
 257
 258                         <table>
 259                                 <title>Specifiers available</title>
 260                                 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
 261                                         <colspec colname="spec" />
 262                                         <colspec colname="mean" />
 263                                         <colspec colname="detail" />
 264                                         <thead>
 265                                                 <row>
 266                                                         <entry>Specifier</entry>
 267                                                         <entry>Meaning</entry>
 268                                                         <entry>Details</entry>
 269                                                 </row>
 270                                         </thead>
 271                                         <tbody>
 272                                                 <row>
 273                                                         <entry><literal>%m</literal></entry>
 274                                                         <entry>Machine ID</entry>
 275                                                         <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>
 276                                                 </row>
 277                                                 <row>
 278                                                         <entry><literal>%b</literal></entry>
 279                                                         <entry>Boot ID</entry>
 280                                                         <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
 281                                                 </row>
 282                                                 <row>
 283                                                         <entry><literal>%H</literal></entry>
 284                                                         <entry>Host name</entry>
 285                                                         <entry>The hostname of the running system.</entry>
 286                                                 </row>
 287                                                 <row>
 288                                                         <entry><literal>%v</literal></entry>
 289                                                         <entry>Kernel release</entry>
 290                                                         <entry>Identical to <command>uname -r</command> output.</entry>
 291                                                 </row>
 292                                                 <row>
 293                                                         <entry><literal>%%</literal></entry>
 294                                                         <entry>Escaped %</entry>
 295                                                         <entry>Single percent sign.</entry>
 296                                                 </row>
 297                                         </tbody>
 298                                 </tgroup>
 299                         </table>
 300                 </refsect2>
 301
 302                 <refsect2>
 303                         <title>Mode</title>
 304
 305                         <para>The file access mode to use when
 306                         creating this file or directory. If omitted or
 307                         when set to -, the default is used: 0755 for
 308                         directories, 0644 for all other file
 309                         objects. For z, Z lines, if omitted or when set
 310                         to -, the file access mode will not be
 311                         modified. This parameter is ignored for x, r,
 312                         R, L lines.</para>
 313                 </refsect2>
 314
 315                 <refsect2>
 316                         <title>UID, GID</title>
 317
 318                         <para>The user and group to use for this file
 319                         or directory. This may either be a numeric
 320                         user/group ID or a user or group name. If
 321                         omitted or when set to -, the default 0 (root)
 322                         is used. For z, Z lines, when omitted or when set to -,
 323                         the file ownership will not be modified.
 324                         These parameters are ignored for x, r, R, L lines.</para>
 325                 </refsect2>
 326
 327                 <refsect2>
 328                         <title>Age</title>
 329                         <para>The date field, when set, is used to
 330                         decide what files to delete when cleaning. If
 331                         a file or directory is older than the current
 332                         time minus the age field, it is deleted. The
 333                         field format is a series of integers each
 334                         followed by one of the following
 335                         postfixes for the respective time units:</para>
 336
 337                         <variablelist>
 338                                 <varlistentry>
 339                                 <term><varname>s</varname></term>
 340                                 <term><varname>min</varname></term>
 341                                 <term><varname>h</varname></term>
 342                                 <term><varname>d</varname></term>
 343                                 <term><varname>w</varname></term>
 344                                 <term><varname>ms</varname></term>
 345                                 <term><varname>m</varname></term>
 346                                 <term><varname>us</varname></term></varlistentry>
 347                         </variablelist>
 348
 349                         <para>If multiple integers and units are specified, the time
 350                         values are summed up. If an integer is given without a unit,
 351                         s is assumed.
 352                         </para>
 353
 354                         <para>When the age is set to zero, the files are cleaned
 355                         unconditionally.</para>
 356
 357                         <para>The age field only applies to lines starting with
 358                         d, D and x. If omitted or set to -, no automatic clean-up
 359                         is done.</para>
 360
 361                         <para>If the age field starts with a tilde
 362                         character (~), the clean-up is only applied to
 363                         files and directories one level inside the
 364                         directory specified, but not the files and
 365                         directories immediately inside it.</para>
 366                 </refsect2>
 367
 368                 <refsect2>
 369                         <title>Argument</title>
 370
 371                         <para>For L lines determines the destination
 372                         path of the symlink. For c, b determines the
 373                         major/minor of the device node, with major and
 374                         minor formatted as integers, separated by :,
 375                         e.g. "1:3". For f, F, w may be used to specify
 376                         a short string that is written to the file,
 377                         suffixed by a newline. Ignored for all other
 378                         lines.</para>
 379                 </refsect2>
 380
 381         </refsect1>
 382
 383         <refsect1>
 384                 <title>Example</title>
 385                 <example>
 386                         <title>/etc/tmpfiles.d/screen.conf example</title>
 387                         <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
 388
 389                         <programlisting>d /var/run/screens  1777 root root 10d
 390 d /var/run/uscreens 0755 root root 10d12h</programlisting>
 391                 </example>
 392                 <example>
 393                         <title>/etc/tmpfiles.d/abrt.conf example</title>
 394                         <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>
 395
 396                         <programlisting>d /var/tmp/abrt 0755 abrt abrt
 397 x /var/tmp/abrt/*</programlisting>
 398                 </example>
 399         </refsect1>
 400
 401         <refsect1>
 402                 <title>See Also</title>
 403                 <para>
 404                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 405                         <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 406                         <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 407                 </para>
 408         </refsect1>
 409
 410 </refentry>