chiark / gitweb /
machined: optionally, allow registration of pre-existing units (scopes
[elogind.git] / man / tmpfiles.d.xml
index e137967..a304dd0 100644 (file)
@@ -7,16 +7,16 @@
   Copyright 2010 Brandon Philips
 
   systemd is free software; you can redistribute it and/or modify it
-  under the terms of the GNU General Public License as published by
-  the Free Software Foundation; either version 2 of the License, or
+  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
-  General Public License for more details.
+  Lesser General Public License for more details.
 
-  You should have received a copy of the GNU General Public License
+  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">
         </refnamediv>
 
         <refsynopsisdiv>
-                <para><filename>/usr/lib/tmpfiles.d/*.conf</filename></para>
                 <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>
+                <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 is named in the style of
-                <filename>&lt;program&gt;.conf</filename>.
-                Files in <filename>/etc/</filename> overwrite
-                files with the same name in <filename>/usr/lib/</filename>.
-                Files in <filename>/run</filename> overwrite files with
-                the same name in <filename>/etc/</filename> and
-                <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
-                administration, which possibly decides to overwrite the
-                configurations installed from packages. All files are sorted
-                by filename in alphabetical order, regardless in which of the
-                directories they reside, to ensure that a specific
-                configuration file takes precedence over another file with
-                an alphabetically later name.</para>
-
-               <para>The configuration format is one line per path
-               containing action, mode, ownership and age
-               fields:</para>
-
-                <programlisting>Type Path          Mode UID  GID  Age
-d    /run/user 0755 root root 10d</programlisting>
+                <title>Configuration Format</title>
+
+                <para>Each configuration file shall be named in the
+                style of
+                <filename><replaceable>package</replaceable>.conf</filename>
+                or
+                <filename><replaceable>package</replaceable>-<replaceable>part</replaceable>.conf</filename>.
+                The second variant should be used when it is desirable
+                to make it easy to override just this part of
+                configuration.</para>
+
+                <para>Files in <filename>/etc/tmpfiles.d</filename>
+                override files with the same name in
+                <filename>/usr/lib/tmpfiles.d</filename> and
+                <filename>/run/tmpfiles.d</filename>. Files in
+                <filename>/run/tmpfiles.d</filename> override files
+                with the same name in
+                <filename>/usr/lib/tmpfiles.d</filename>. Packages
+                should install their configuration files in
+                <filename>/usr/lib/tmpfiles.d</filename>. Files in
+                <filename>/etc/tmpfiles.d</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 of which
+                of the directories they reside in. 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 type, 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 type consists of a single letter and
+                        optionally an exclamation mark.</para>
+
+                        <para>The following line types are understood:</para>
+
                         <variablelist>
                                 <varlistentry>
                                         <term><varname>f</varname></term>
-                                        <listitem><para>Create a file if it doesn't exist yet</para></listitem>
+                                        <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>
                                 </varlistentry>
 
                                 <varlistentry>
                                         <term><varname>F</varname></term>
-                                        <listitem><para>Create or truncate a file</para></listitem>
+                                        <listitem><para>Create or truncate a file. If the argument parameter is given, it will be written to the file.</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 doesn't exist yet</para></listitem>
+                                        <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>
+                                        <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 doesn't exist yet</para></listitem>
+                                        <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
+                                        security context. If it does not exist, do
+                                        nothing.</para></listitem>
                                 </varlistentry>
 
                                 <varlistentry>
@@ -125,23 +186,45 @@ d    /run/user 0755 root root 10d</programlisting>
                                         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
+                                        effect of <varname>r</varname>
+                                        or <varname>R</varname> lines.
+                                        Lines of this type accept
                                         shell-style globs in place of
-                                        of normal path
-                                        names.</para></listitem>
+                                        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
+                                        <varname>x</varname>, 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 <varname>r</varname>
+                                        or <varname>R</varname> 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
+                                        or directory if it exists.
+                                        This may not be used to remove
+                                        non-empty directories, use
+                                        <varname>R</varname> for that.
+                                        Lines of this type accept
+                                        shell-style globs in place of
+                                        normal path
                                         names.</para></listitem>
                                 </varlistentry>
 
@@ -157,16 +240,104 @@ d    /run/user 0755 root root 10d</programlisting>
                                 </varlistentry>
 
                                 <varlistentry>
+                                        <term><varname>z</varname></term>
+                                        <listitem><para>Restore
+                                        SELinux security context
+                                        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 set
-                                        ownership, access mode and relabel
-                                        security context 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>
+                                        <listitem><para>Recursively
+                                        restore SELinux security
+                                        context 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>
+
+                        <para>If the exclamation mark is used, this
+                        line is only safe of execute during boot, and
+                        can break a running system. Lines without the
+                        exclamation mark are presumed to be safe to
+                        execute at any time, e.g. on package upgrades.
+                        <command>systemd-tmpfiles</command> will
+                        execute line with an exclamation mark only if
+                        option <option>--boot</option> is given.
+                        </para>
+
+                        <para>For example:
+                        <programlisting>
+# Make sure these are created by default so that nobody else can
+d /tmp/.X11-unix 1777 root root 10d
+
+# Unlink the X11 lock files
+r! /tmp/.X[0-9]*-lock
+                        </programlisting>
+                        The second line in contrast to the first one
+                        would break a running system, and will only be
+                        executed with <option>--boot</option>.</para>
+                </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>
@@ -174,11 +345,15 @@ d    /run/user 0755 root root 10d</programlisting>
 
                         <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 files. For Z lines
-                        if omitted or when set to - the file access mode will
-                        not be modified. This parameter is ignored for x, r, R
-                        lines.</para>
+                        when set to -, the default is used: 0755 for
+                        directories, 0644 for all other file objects.
+                        For <varname>z</varname>, <varname>Z</varname>
+                        lines, if omitted or when set to
+                        <literal>-</literal>, the file access mode
+                        will not be modified. This parameter is
+                        ignored for <varname>x</varname>,
+                        <varname>r</varname>, <varname>R</varname>,
+                        <varname>L</varname> lines.</para>
                 </refsect2>
 
                 <refsect2>
@@ -187,10 +362,15 @@ d    /run/user 0755 root root 10d</programlisting>
                         <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 lines when omitted or when set to -
-                        the file ownership will not be modified.
-                        These parameters are ignored for x, r, R lines.</para>
+                        omitted or when set to <literal>-</literal>,
+                        the default 0 (root) is used. For
+                        <varname>z</varname>, <varname>Z</varname>
+                        lines, when omitted or when set to -, the file
+                        ownership will not be modified. These
+                        parameters are ignored for
+                        <varname>x</varname>, <varname>r</varname>,
+                        <varname>R</varname>, <varname>L</varname>
+                        lines.</para>
                 </refsect2>
 
                 <refsect2>
@@ -198,7 +378,7 @@ d    /run/user 0755 root root 10d</programlisting>
                         <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
+                        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>
@@ -215,12 +395,45 @@ d    /run/user 0755 root root 10d</programlisting>
                                 <term><varname>us</varname></term></varlistentry>
                         </variablelist>
 
-                        <para>If multiple integers and units are specified the time
-                        values are summed up.</para>
+                        <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 <varname>d</varname>,
+                        <varname>D</varname>, and
+                        <varname>x</varname>. If omitted or set to
+                        <literal>-</literal>, no automatic clean-up is
+                        done.</para>
+
+                        <para>If the age field starts with a tilde
+                        character <literal>~</literal>, 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>
 
-                        <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>
+                <refsect2>
+                        <title>Argument</title>
+
+                        <para>For <varname>L</varname> lines
+                        determines the destination path of the
+                        symlink. For <varname>c</varname>,
+                        <varname>b</varname> determines the
+                        major/minor of the device node, with major and
+                        minor formatted as integers, separated by
+                        <literal>:</literal>, e.g.
+                        <literal>1:3</literal>. For
+                        <varname>f</varname>, <varname>F</varname>,
+                        and <varname>w</varname> 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>
@@ -231,16 +444,24 @@ d    /run/user 0755 root root 10d</programlisting>
                         <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
+                        <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-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>systemd-delta</refentrytitle><manvolnum>1</manvolnum></citerefentry>
                 </para>
         </refsect1>