systemd-hwdb: introduce new tool

This pulls out the hwdb managment from udevadm into an independent tool.

The old code is left in place for backwards compatibility, and easy of
testing, but all documentation is dropped to encourage use of the new
tool instead.

1 files changed, 87 insertions, 0 deletions

diff --git a/man/hwdb.xml b/man/hwdb.xml
new file mode 100644
index 0000000000..9f2aff3261
--- /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>