systemd/man/tmpfiles.d.xml

<?xml version="1.0"?>
<!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
  This file is part of systemd.

  Copyright 2010 Brandon Philips

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="tmpfiles.d">

        <refentryinfo>
                <title>tmpfiles.d</title>
                <productname>systemd</productname>

                <authorgroup>
                        <author>
                                <contrib>Documentation</contrib>
                                <firstname>Brandon</firstname>
                                <surname>Philips</surname>
                                <email>brandon@ifup.org</email>
                        </author>
                </authorgroup>
        </refentryinfo>

        <refmeta>
                <refentrytitle>tmpfiles.d</refentrytitle>
                <manvolnum>5</manvolnum>
        </refmeta>

        <refnamediv>
                <refname>tmpfiles.d</refname>
                <refpurpose>Configuration for creation, deletion and
                cleaning of volatile and temporary files</refpurpose>
        </refnamediv>

        <refsynopsisdiv>
                <para><filename>/etc/tmpfiles.d/*.conf</filename></para>
                <para><filename>/run/tmpfiles.d/*.conf</filename></para>
                <para><filename>/usr/lib/tmpfiles.d/*.conf</filename></para>
        </refsynopsisdiv>

        <refsect1>
                <title>Description</title>

                <para><command>systemd-tmpfiles</command> uses the
                configuration files from the above directories to describe the
                creation, cleaning and removal of volatile and
                temporary files and directories which usually reside
                in directories such as <filename>/run</filename>
                or <filename>/tmp</filename>.</para>
        </refsect1>

        <refsect1>
                <title>Configuration Format</title>

                <para>Each configuration file shall be named in the
                style of <filename>&lt;package&gt;.conf</filename>.
                Files in <filename>/etc/</filename> override files
                with the same name in <filename>/usr/lib/</filename>
                and <filename>/run/</filename>.  Files in
                <filename>/run/</filename> override files with the same
                name in <filename>/usr/lib/</filename>. Packages
                should install their configuration files in
                <filename>/usr/lib/</filename>. Files in
                <filename>/etc/</filename> are reserved for the local
                administrator, who may use this logic to override the
                configuration files installed by vendor packages. All
                configuration files are sorted by their filename in
                lexicographic order, regardless in which of the
                directories they reside. If multiple files specify the
                same path, the entry in the file with the lexicographically
                earliest name will be applied, all all other conflicting
                entries logged as errors.</para>

                <para>If the administrator wants to disable a
                configuration file supplied by the vendor, the
                recommended way is to place a symlink to
                <filename>/dev/null</filename> in
                <filename>/etc/tmpfiles.d/</filename> bearing the
                same filename.</para>

                <para>The configuration format is one line per path
                containing action, path, mode, ownership, age and argument
                fields:</para>

                <programlisting>Type Path        Mode UID  GID  Age Argument
d    /run/user   0755 root root 10d -
L    /tmp/foobar -    -    -    -   /dev/null</programlisting>


                <refsect2>
                        <title>Type</title>

                        <para>The following line types are understood:</para>

                        <variablelist>
                                <varlistentry>
                                        <term><varname>f</varname></term>
                                        <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>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>F</varname></term>
                                        <listitem><para>Create or truncate a file (optionally writing a short string into it, if the argument parameter is passed)</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>w</varname></term>
                                        <listitem><para>Write the argument parameter to a file, if the file exists.
                                            Lines of this type accept shell-style globs in place of normal path
                                            names. The argument parameter will be written without a trailing
                                            newline. C-style backslash escapes are interpreted.</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>d</varname></term>
                                        <listitem><para>Create a directory if it does not exist yet</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>D</varname></term>
                                        <listitem><para>Create or empty a directory</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>p</varname></term>
                                        <listitem><para>Create a named pipe (FIFO) if it does not exist yet</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>L</varname></term>
                                        <listitem><para>Create a symlink if it does not exist yet</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>c</varname></term>
                                        <listitem><para>Create a character device node if it does not exist yet</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>b</varname></term>
                                        <listitem><para>Create a block device node if it does not exist yet</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>m</varname></term>
                                        <listitem><para>If the
                                        specified file path exists,
                                        adjust its access mode, group
                                        and user to the specified
                                        values and reset the SELinux
                                        label. If it does not exist, do
                                        nothing.</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>x</varname></term>
                                        <listitem><para>Ignore a path
                                        during cleaning. Use this type
                                        to exclude paths from clean-up
                                        as controlled with the Age
                                        parameter. Note that lines of
                                        this type do not influence the
                                        effect of r or R lines. Lines
                                        of this type accept
                                        shell-style globs in place of
                                        normal path
                                        names.</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>X</varname></term>
                                        <listitem><para>Ignore a path
                                        during cleaning. Use this type
                                        to exclude paths from clean-up
                                        as controlled with the Age
                                        parameter. Unlike x, this
                                        parameter will not exclude the
                                        content if path is a directory,
                                        but only directory itself.
                                        Note that lines of this type do
                                        not influence the effect of r
                                        or R lines. Lines of this type
                                        accept shell-style globs in
                                        place of normal path
                                        names.</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>r</varname></term>
                                        <listitem><para>Remove a file
                                        or directory if it
                                        exists. This may not be used
                                        to remove non-empty
                                        directories, use R for
                                        that. Lines of this type
                                        accept shell-style globs in
                                        place of normal path
                                        names.</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>R</varname></term>
                                        <listitem><para>Recursively
                                        remove a path and all its
                                        subdirectories (if it is a
                                        directory). Lines of this type
                                        accept shell-style globs in
                                        place of normal path
                                        names.</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>z</varname></term>
                                        <listitem><para>Restore
                                        SELinux security context label
                                        and set ownership and access
                                        mode of a file or directory if
                                        it exists.  Lines of this type
                                        accept shell-style globs in
                                        place of normal path names.
                                        </para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>Z</varname></term>
                                        <listitem><para>Recursively
                                        restore SELinux security
                                        context label and set
                                        ownership and access mode of a
                                        path and all its
                                        subdirectories (if it is a
                                        directory). Lines of this type
                                        accept shell-style globs in
                                        place of normal path
                                        names.</para></listitem>
                                </varlistentry>
                        </variablelist>
                </refsect2>

                <refsect2>
                        <title>Path</title>

                        <para>The file system path specification supports simple specifier
                        expansion. The following expansions are
                        understood:</para>

                        <table>
                                <title>Specifiers available</title>
                                <tgroup cols='3' align='left' colsep='1' rowsep='1'>
                                        <colspec colname="spec" />
                                        <colspec colname="mean" />
                                        <colspec colname="detail" />
                                        <thead>
                                                <row>
                                                        <entry>Specifier</entry>
                                                        <entry>Meaning</entry>
                                                        <entry>Details</entry>
                                                </row>
                                        </thead>
                                        <tbody>
                                                <row>
                                                        <entry><literal>%m</literal></entry>
                                                        <entry>Machine ID</entry>
                                                        <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>
                                                </row>
                                                <row>
                                                        <entry><literal>%b</literal></entry>
                                                        <entry>Boot ID</entry>
                                                        <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
                                                </row>
                                                <row>
                                                        <entry><literal>%H</literal></entry>
                                                        <entry>Host name</entry>
                                                        <entry>The hostname of the running system.</entry>
                                                </row>
                                                <row>
                                                        <entry><literal>%v</literal></entry>
                                                        <entry>Kernel release</entry>
                                                        <entry>Identical to <command>uname -r</command> output.</entry>
                                                </row>
                                                <row>
                                                        <entry><literal>%%</literal></entry>
                                                        <entry>Escaped %</entry>
                                                        <entry>Single percent sign.</entry>
                                                </row>
                                        </tbody>
                                </tgroup>
                        </table>
                </refsect2>

                <refsect2>
                        <title>Mode</title>

                        <para>The file access mode to use when
                        creating this file or directory. If omitted or
                        when set to -, the default is used: 0755 for
                        directories, 0644 for all other file
                        objects. For z, Z lines, if omitted or when set
                        to -, the file access mode will not be
                        modified. This parameter is ignored for x, r,
                        R, L lines.</para>
                </refsect2>

                <refsect2>
                        <title>UID, GID</title>

                        <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 name. If
                        omitted or when set to -, the default 0 (root)
                        is used. For z, Z lines, when omitted or when set to -,
                        the file ownership will not be modified.
                        These parameters are ignored for x, r, R, L lines.</para>
                </refsect2>

                <refsect2>
                        <title>Age</title>
                        <para>The date field, when set, is used to
                        decide what files to delete when cleaning. If
                        a file or directory is older than the current
                        time minus the age field, it is deleted. The
                        field format is a series of integers each
                        followed by one of the following
                        postfixes for the respective time units:</para>

                        <variablelist>
                                <varlistentry>
                                <term><varname>s</varname></term>
                                <term><varname>min</varname></term>
                                <term><varname>h</varname></term>
                                <term><varname>d</varname></term>
                                <term><varname>w</varname></term>
                                <term><varname>ms</varname></term>
                                <term><varname>m</varname></term>
                                <term><varname>us</varname></term></varlistentry>
                        </variablelist>

                        <para>If multiple integers and units are specified, the time
                        values are summed up. If an integer is given without a unit,
                        s is assumed.
                        </para>

                        <para>When the age is set to zero, the files are cleaned
                        unconditionally.</para>

                        <para>The age field only applies to lines starting with
                        d, D and x. If omitted or set to -, no automatic clean-up
                        is done.</para>

                        <para>If the age field starts with a tilde
                        character (~), the clean-up is only applied to
                        files and directories one level inside the
                        directory specified, but not the files and
                        directories immediately inside it.</para>
                </refsect2>

                <refsect2>
                        <title>Argument</title>

                        <para>For L lines determines the destination
                        path of the symlink. For c, b determines the
                        major/minor of the device node, with major and
                        minor formatted as integers, separated by :,
                        e.g. "1:3". For f, F, w may be used to specify
                        a short string that is written to the file,
                        suffixed by a newline. Ignored for all other
                        lines.</para>
                </refsect2>

        </refsect1>

        <refsect1>
                <title>Example</title>
                <example>
                        <title>/etc/tmpfiles.d/screen.conf example</title>
                        <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>

                        <programlisting>d /var/run/screens  1777 root root 10d
d /var/run/uscreens 0755 root root 10d12h</programlisting>
                </example>
                <example>
                        <title>/etc/tmpfiles.d/abrt.conf example</title>
                        <para><command>abrt</command> needs a directory created at boot with specific mode and ownership and its content should be preserved.</para>

                        <programlisting>d /var/tmp/abrt 0755 abrt abrt
x /var/tmp/abrt/*</programlisting>
                </example>
        </refsect1>

        <refsect1>
                <title>See Also</title>
                <para>
                        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                        <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
                        <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>
                </para>
        </refsect1>

</refentry>