systemd-hwdb: introduce new tool

[elogind.git] / man / hwdb.xml

diff --git a/man/hwdb.xml b/man/hwdb.xml
new file mode 100644 (file)
index 0000000..9f2aff3
--- /dev/null
+++ b/man/hwdb.xml
@@ -0,0 +1,87 @@
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
+<?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+
+<refentry id="hwdb">
+  <refentryinfo>
+    <title>hwdb</title>
+    <productname>systemd</productname>
+    <authorgroup>
+      <author>
+        <contrib>Developer</contrib>
+        <firstname>Kay</firstname>
+        <surname>Sievers</surname>
+        <email>kay@vrfy.org</email>
+      </author>
+      <author>
+        <contrib>Developer</contrib>
+        <firstname>Tom</firstname>
+        <surname>Gundersen</surname>
+        <email>teg@jklm.no</email>
+      </author>
+    </authorgroup>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>hwdb</refentrytitle>
+    <manvolnum>7</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>hwdb</refname>
+    <refpurpose>Hardware Database</refpurpose>
+  </refnamediv>
+
+  <refsect1><title>Description</title>
+    <para>The hardware database is a key-value store for associating modalias-like keys to
+    udev-properties-like values. It is used primarily by udev to add the relevant properties
+    to matching devices, but it can also be queried directly.</para>
+  </refsect1>
+
+  <refsect1><title>Hardware Database Files</title>
+      <para>The hwdb files are read from the files located in the
+      system hwdb directory <filename>/usr/lib/udev/hwdb.d</filename>,
+      the volatile runtime directory <filename>/run/udev/hwdb.d</filename>
+      and the local administration directory <filename>/etc/udev/hwdb.d</filename>.
+      All hwdb files are collectively sorted and processed in lexical order,
+      regardless of the directories in which they live. However, files with
+      identical filenames replace each other. Files in <filename>/etc</filename>
+      have the highest priority, files in <filename>/run</filename> take precedence
+      over files with the same name in <filename>/usr/lib</filename>. This can be
+      used to override a system-supplied hwdb file with a local file if needed;
+      a symlink in <filename>/etc</filename> with the same name as a hwdb file in
+      <filename>/usr/lib</filename>, pointing to <filename>/dev/null</filename>,
+      disables the hwdb file entirely. hwdb files must have the extension
+      <filename>.hwdb</filename>; other extensions are ignored.</para>
+
+      <para>The hwdb file contains data records consisting of matches and
+      associated key-value pairs. Every record in the hwdb starts with one or
+      more match string, specifying a shell glob to compare the database
+      lookup string against. Multiple match lines are specified in additional
+      consecutive lines. Every match line is compared indivdually, they are
+      combined by OR. Every match line must start at the first character of
+      the line.</para>
+
+      <para>The match lines are followed by one or more key-value pair lines, which
+      are recognized by a leading space character. The key name and value are separated
+      by <literal>=</literal>. An empty line signifies the end
+      of a record. Lines beginning with <literal>#</literal> are ignored.</para>
+
+      <para>The content of all hwdb files is read by
+      <citerefentry><refentrytitle>systemd-hwdb</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+      and compiled to a binary database located at <filename>/etc/udev/hwdb.bin</filename>,
+      or alternatively <filename>/usr/lib/udev/hwdb.bin</filename> if you want ship the compiled
+      database in an immutable image.
+      During runtime only the binary database is used.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>See Also</title>
+    <para>
+      <citerefentry>
+        <refentrytitle>systemd-hwdb</refentrytitle><manvolnum>8</manvolnum>
+      </citerefentry>
+    </para>
+  </refsect1>
+</refentry>