systemd/man/tmpfiles.d.xml

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<?xml version="1.0"?>
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Copyright 2010 Brandon Philips
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<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><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 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. 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 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
security context. 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 <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>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
<varname>R</varname> 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
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 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>
<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 <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>
<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 <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>
<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 <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>
<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>
<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>