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+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
+ "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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SPDX-License-Identifier: LGPL-2.1+
<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>Volatile and temporary files and directories are those located in <filename>/run</filename>,
- <filename>/tmp</filename>, <filename>/var/tmp</filename>, the API file systems such as <filename>/sys</filename> or
- <filename>/proc</filename>, as well as some other directories below <filename>/var</filename>.</para>
-
- <para>System daemons frequently require private runtime
- directories below <filename>/run</filename> to place communication
- sockets and similar in. For these, consider declaring them in
- their unit files using <varname>RuntimeDirectory=</varname> (see
- <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- for details), if this is feasible.</para>
+ <para><filename>tmpfiles.d</filename> configuration files provide a generic mechanism to define the
+ <emphasis>creation</emphasis> of regular files, directories, pipes, and device nodes, adjustments to
+ their <emphasis>access mode, ownership, attributes, quota assignments, and contents</emphasis>, and
+ finally their time-based <emphasis>removal</emphasis>. It is mostly commonly used for volatile and
+ temporary files and directories (such as those located under <filename>/run</filename>,
+ <filename>/tmp</filename>, <filename>/var/tmp</filename>, the API file systems such as
+ <filename>/sys</filename> or <filename>/proc</filename>, as well as some other directories below
+ <filename>/var</filename>).</para>
+
+ <para><command>systemd-tmpfiles</command> uses this configuration to create volatile files and
+ directories during boot and to do periodic cleanup afterwards. See
+ <citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
+ the description of <filename>systemd-tmpfiles-setup.service</filename>,
+ <filename>systemd-tmpfiles-cleanup.service</filename>, and associated units.</para>
+
+ <para>System daemons frequently require private runtime directories below <filename>/run</filename> to
+ store communication sockets and similar. For these, is is better to use
+ <varname>RuntimeDirectory=</varname> in their unit files (see
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
+ details), if the flexibility provided by <filename>tmpfiles.d</filename> is not required. The advantages
+ are that the configuration required by the unit is centralized in one place, and that the lifetime of the
+ directory is tied to the lifetime of the service itself. Similarly, <varname>StateDirectory=</varname>,
+ <varname>CacheDirectory=</varname>, <varname>LogsDirectory=</varname>, and
+ <varname>ConfigurationDirectory=</varname> should be used to create directories under
+ <filename>/var/lib/</filename>, <filename>/var/cache/</filename>, <filename>/var/log/</filename>, and
+ <filename>/etc/</filename>. <filename>tmpfiles.d</filename> should be used for files whose lifetime is
+ independent of any service or requires more complicated configuration.</para>
</refsect1>
<refsect1>
name will be applied. All other conflicting entries will be logged as errors. When two lines are prefix path and
suffix path of each other, then the prefix line is always created first, the suffix later (and if removal applies
to the line, the order is reversed: the suffix is removed first, the prefix later). Lines that take globs are
- applied after those accepting no globs. If multiple operations shall be applied on the same file, (such as ACL,
- xattr, file attribute adjustments), these are always done in the same fixed order. Otherwise, the files/directories
- are processed in the order they are listed.</para>
+ applied after those accepting no globs. If multiple operations shall be applied on the same file (such as ACL,
+ xattr, file attribute adjustments), these are always done in the same fixed order. Except for those cases, the
+ files/directories are processed in the order they are listed.</para>
<para>If the administrator wants to disable a configuration file
supplied by the vendor, the recommended way is to place a symlink
<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>
+ <programlisting>#Type Path Mode User Group Age Argument
+d /run/user 0755 root root 10d -
+L /tmp/foobar - - - - /dev/null</programlisting>
<para>Fields may be enclosed within quotes and contain C-style escapes.</para>
<varlistentry>
<term><varname>d</varname></term>
- <listitem><para>Create a directory. The mode and ownership will be adjusted if
- specified and the directory already exists. Contents of this directory are subject
- to time based cleanup if the age argument is specified.</para></listitem>
+ <listitem><para>Create a directory. The mode and ownership will be adjusted if specified. Contents
+ of this directory are subject to time based cleanup if the age argument is specified.
+ </para></listitem>
</varlistentry>
<varlistentry>
<term><varname>D</varname></term>
- <listitem><para>Similar to <varname>d</varname>, but in addition the contents
- of the directory will be removed when <option>--remove</option> is used.
- </para></listitem>
+ <listitem><para>Similar to <varname>d</varname>, but in addition the contents of the directory will
+ be removed when <option>--remove</option> is used.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>e</varname></term>
- <listitem><para>Similar to <varname>d</varname>, but the directory will not be created if
- it does not exist. Lines of this type accept shell-style globs in place of normal path
- names. For this entry to be useful, at least one of the mode, uid, gid, or age arguments
- must be specified, since otherwise this entry has no effect. If the age argument is
- <literal>0</literal>, contents of the directory will be unconditionally deleted every time
- <command>systemd-tmpfiles --clean</command> is run. This can be useful when combined with
- <varname>!</varname>, see the examples.</para></listitem>
+ <listitem><para>Adjust the mode and ownership of existing directories and remove their contents
+ based on age.
+ Lines of this type accept shell-style globs in place of normal path names. Contents of the
+ directories are subject to time based cleanup if the age argument is specified. If the age argument
+ is <literal>0</literal>, contents will be unconditionally deleted every time
+ <command>systemd-tmpfiles --clean</command> is run.</para>
+
+ <para>For this entry to be useful, at least one of the mode, user, group, or age arguments must be
+ specified, since otherwise this entry has no effect. As an exception, an entry with no effect may
+ be useful when combined with <varname>!</varname>, see the examples.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>v</varname></term>
- <listitem><para>Create a subvolume if the path does not
- exist yet, the file system supports subvolumes (btrfs), and
- the system itself is installed into a subvolume
- (specifically: the root directory <filename>/</filename> is
- itself a subvolume). Otherwise, create a normal directory, in
- the same way as <varname>d</varname>. A subvolume created
- with this line type is not assigned to any higher-level
- quota group. For that, use <varname>q</varname> or
- <varname>Q</varname>, which allow creating simple quota
- group hierarchies, see below.</para></listitem>
+ <listitem><para>Create a subvolume if the path does not exist yet, the file system supports
+ subvolumes (btrfs), and the system itself is installed into a subvolume (specifically: the root
+ directory <filename>/</filename> is itself a subvolume). Otherwise, create a normal directory, in
+ the same way as <varname>d</varname>.</para>
+
+ <para>A subvolume created with this line type is not assigned to any higher-level quota group. For
+ that, use <varname>q</varname> or <varname>Q</varname>, which allow creating simple quota group
+ hierarchies, see below.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>q</varname></term>
- <listitem><para>Similar to <varname>v</varname>. However, makes sure that the subvolume will be assigned to
- the same higher-level quota groups as the subvolume it has been created in. This ensures that higher-level
- limits and accounting applied to the parent subvolume also include the specified subvolume. On non-btrfs file
- systems, this line type is identical to <varname>d</varname>.</para>
+ <listitem><para>Create a subvolume or directory the same as <varname>v</varname>, but assign the
+ subvolume to the same higher-level quota groups as the parent. This ensures that higher-level
+ limits and accounting applied to the parent subvolume also include the specified subvolume. On
+ non-btrfs file systems, this line type is identical to <varname>d</varname>.</para>
<para>If the subvolume already exists, no change to the quota hierarchy is made, regardless of whether the
subvolume is already attached to a quota group or not. Also see <varname>Q</varname> below. See <citerefentry
<varlistentry>
<term><varname>Q</varname></term>
- <listitem><para>Similar to <varname>q</varname>. However, instead of copying the higher-level quota group
- assignments from the parent as-is, the lowest quota group of the parent subvolume is determined that is not
- the leaf quota group. Then, an "intermediary" quota group is inserted that is one level below this level, and
- shares the same ID part as the specified subvolume. If no higher-level quota group exists for the parent
- subvolume, a new quota group at level 255 sharing the same ID as the specified subvolume is inserted
- instead. This new intermediary quota group is then assigned to the parent subvolume's higher-level quota
- groups, and the specified subvolume's leaf quota group is assigned to it.</para>
+ <listitem><para>Create the subvolume or directory the same as <varname>v</varname>, but assign the
+ new subvolume to a new leaf quota group. Instead of copying the higher-level quota group
+ assignments from the parent as is done with <varname>q</varname>, the lowest quota group of the
+ parent subvolume is determined that is not the leaf quota group. Then, an "intermediary" quota
+ group is inserted that is one level below this level, and shares the same ID part as the specified
+ subvolume. If no higher-level quota group exists for the parent subvolume, a new quota group at
+ level 255 sharing the same ID as the specified subvolume is inserted instead. This new intermediary
+ quota group is then assigned to the parent subvolume's higher-level quota groups, and the specified
+ subvolume's leaf quota group is assigned to it.</para>
<para>Effectively, this has a similar effect as <varname>q</varname>, however introduces a new higher-level
quota group for the specified subvolume that may be used to enforce limits and accounting to the specified
<filename>/var/tmp</filename>. </para>
<para>As with <varname>q</varname>, <varname>Q</varname> has no effect on the quota group hierarchy if the
- subvolume already exists, regardless of whether the subvolume already belong to a quota group or
- not.</para></listitem>
+ subvolume already exists, regardless of whether the subvolume already belong to a quota group or not.
+ </para></listitem>
</varlistentry>
<varlistentry>
<varlistentry>
<term><varname>C</varname></term>
<listitem><para>Recursively copy a file or directory, if the
- destination files or directories do not exist yet. Note that
- this command will not descend into subdirectories if the
- destination directory already exists. Instead, the entire
- copy operation is skipped. If the argument is omitted, files
- from the source directory
+ destination files or directories do not exist yet or the
+ destination directory is empty. Note that this command will not
+ descend into subdirectories if the destination directory already
+ exists and is not empty. Instead, the entire copy operation is
+ skipped. If the argument is omitted, files from the source directory
<filename>/usr/share/factory/</filename> with the same name
are copied. Does not follow symlinks.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>z</varname></term>
- <listitem><para>Adjust the access mode, group and user, and
- restore the SELinux security context of a file or directory,
- if it exists. Lines of this type accept shell-style globs in
- place of normal path names. Does not follow symlinks.</para></listitem>
+ <listitem><para>Adjust the access mode, user and group ownership, and restore the SELinux security
+ context of a file or directory, if it exists. Lines of this type accept shell-style globs in place
+ of normal path names. Does not follow symlinks.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>Z</varname></term>
- <listitem><para>Recursively set the access mode, group and
- user, and restore the SELinux security context of a file or
- directory if it exists, as well as of its subdirectories and
- the files contained therein (if applicable). Lines of this
- type accept shell-style globs in place of normal path
- names. Does not follow symlinks. </para></listitem>
+ <listitem><para>Recursively set the access mode, user and group ownership, and restore the SELinux
+ security context of a file or directory if it exists, as well as of its subdirectories and the
+ files contained therein (if applicable). Lines of this type accept shell-style globs in place of
+ normal path names. Does not follow symlinks.</para></listitem>
</varlistentry>
<varlistentry>
<listitem><para>Set file/directory attributes. Lines of this type
accept shell-style globs in place of normal path names.</para>
- <para>The format of the argument field is
- <varname>[+-=][aAcCdDeijsStTu] </varname>. The prefix
- <varname>+</varname> (the default one) causes the
- attribute(s) to be added; <varname>-</varname> causes the
- attribute(s) to be removed; <varname>=</varname> causes the
- attributes to be set exactly as the following letters. The
- letters <literal>aAcCdDeijsStTu</literal> select the new
- attributes for the files, see
- <citerefentry project='man-pages'><refentrytitle>chattr</refentrytitle>
+ <para>The format of the argument field is <varname>[+-=][aAcCdDeijPsStTu] </varname>. The prefix
+ <varname>+</varname> (the default one) causes the attribute(s) to be added; <varname>-</varname>
+ causes the attribute(s) to be removed; <varname>=</varname> causes the attributes to be set exactly
+ as the following letters. The letters <literal>aAcCdDeijPsStTu</literal> select the new attributes
+ for the files, see <citerefentry project='man-pages'><refentrytitle>chattr</refentrytitle>
<manvolnum>1</manvolnum></citerefentry> for further information.
</para>
<para>Passing only <varname>=</varname> as argument resets
</varlistentry>
</variablelist>
- <para>If the exclamation mark is used, this line is only safe of
+ <para>If the exclamation mark is used, this line is only safe to
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.
</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 user/group ID of the user who invokes <command>systemd-tmpfiles</command> is used.
- For <varname>z</varname> and <varname>Z</varname> lines, when omitted or when set to <literal>-</literal>, the file ownership will not be
- modified. These parameters are ignored for <varname>x</varname>, <varname>r</varname>, <varname>R</varname>, <varname>L</varname>,
- <varname>t</varname>, and <varname>a</varname> lines.</para>
+ <title>User, Group</title>
+
+ <para>The user and group to use for this file or directory. This may either be a numeric ID or a
+ user/group name. If omitted or when set to <literal>-</literal>, the user and group of the user who
+ invokes <command>systemd-tmpfiles</command> is used. For <varname>z</varname> and <varname>Z</varname>
+ lines, when omitted or when set to <literal>-</literal>, the file ownership will not be modified. These
+ parameters are ignored for <varname>x</varname>, <varname>r</varname>, <varname>R</varname>,
+ <varname>L</varname>, <varname>t</varname>, and <varname>a</varname> lines.</para>
</refsect2>
<refsect2>
(ctime). Any of these three (or two) values will prevent cleanup
if it is more recent than the current time minus the age
field.</para>
+
+ <para>Note that while the aging algorithm is run a 'shared' BSD file lock (see <citerefentry
+ project='man-pages'><refentrytitle>flock</refentrytitle><manvolnum>2</manvolnum></citerefentry>) is
+ taken on each directory the algorithm descends into (and each directory below that, and so on). If the
+ aging algorithm finds a lock is already taken on some directory, it (and everything below it) is
+ skipped. Applications may use this to temporarily exclude certain directory subtrees from the aging
+ algorithm: the applications can take a BSD file lock themselves, and as long as they keep it aging of
+ the directory and everything below it is disabled.</para>
</refsect2>
<refsect2>
</example>
</refsect1>
+ <refsect1>
+ <title><filename>/run/</filename> and <filename>/var/run/</filename></title>
+ <para><filename>/var/run/</filename> is a deprecated symlink to <filename>/run/</filename>, and
+ applications should use the latter. <command>systemd-tmpfiles</command> will warn if
+ <filename>/var/run/</filename> is used.</para>
+ </refsect1>
+
<refsect1>
<title>See Also</title>
<para>
projects / thirdparty / systemd.git / blobdiff