source: chapter08/udev.xml@ d6f618b

xry111/loongarch xry111/loongarch-12.0 xry111/loongarch-12.1
Last change on this file since d6f618b was 2882861, checked in by Xi Ruoyao <xry111@…>, 11 months ago

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1<?xml version="1.0" encoding="ISO-8859-1"?>
2<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
4 <!ENTITY % general-entities SYSTEM "../general.ent">
5 %general-entities;
6]>
7
8<sect1 id="ch-system-udev" role="wrap" revision="sysv">
9 <?dbhtml filename="udev.html"?>
10
11 <sect1info condition="script">
12 <productname>udev</productname>
13 <productnumber>&systemd-version;</productnumber>
14 <address>&systemd-url;</address>
15 </sect1info>
16
17 <title>Udev from Systemd-&systemd-version;</title>
18
19 <indexterm zone="ch-system-udev">
20 <primary sortas="a-Udev">Udev</primary>
21 </indexterm>
22
23 <sect2 role="package">
24 <title/>
25
26 <para>The Udev package contains programs for dynamic creation of device
27 nodes.</para>
28
29 <segmentedlist>
30 <segtitle>&buildtime;</segtitle>
31 <segtitle>&diskspace;</segtitle>
32
33 <seglistitem>
34 <seg>&udev-fin-sbu;</seg>
35 <seg>&udev-fin-du;</seg>
36 </seglistitem>
37 </segmentedlist>
38 </sect2>
39
40 <sect2 role="installation">
41 <title>Installation of Udev</title>
42
43 <para>Udev is part of the systemd-&systemd-version; package. Use
44 the systemd-&systemd-version;.tar.xz file as the source tarball.</para>
45
46 <para>Remove two unneeded groups,
47 <systemitem class="groupname">render</systemitem> and
48 <systemitem class="groupname">sgx</systemitem>, from the default udev
49 rules:</para>
50
51 <screen><userinput remap="pre">sed -i -e 's/GROUP="render"/GROUP="video"/' \
52 -e 's/GROUP="sgx", //' rules.d/50-udev-default.rules.in</userinput></screen>
53
54 <para>Remove one udev rule requiring a full Systemd installation:</para>
55
56 <screen><userinput remap="pre">sed '/systemd-sysctl/s/^/#/' -i rules.d/99-systemd.rules.in</userinput></screen>
57
58 <para>Prepare Udev for compilation:</para>
59
60<screen><userinput remap="configure">mkdir -p build
61cd build
62
63CFLAGS+=" -Wno-format-overflow" \
64meson setup \
65 --prefix=/usr \
66 --buildtype=release \
67 -Dmode=release \
68 -Ddev-kvm-mode=0660 \
69 -Dlink-udev-shared=false \
70 ..</userinput></screen>
71
72 <variablelist>
73 <title>The meaning of the meson options:</title>
74
75 <varlistentry>
76 <term><parameter>--buildtype=release</parameter></term>
77 <listitem>
78 <para>This switch overrides the default buildtype
79 (<quote>debug</quote>), which produces unoptimized
80 binaries.</para>
81 </listitem>
82 </varlistentry>
83
84 <varlistentry>
85 <term><parameter>-Dmode=release</parameter></term>
86 <listitem>
87 <para>Disable some features considered experimental by upstream.
88 </para>
89 </listitem>
90 </varlistentry>
91
92 <varlistentry>
93 <term><parameter>-Ddev-kvm-mode=0660</parameter></term>
94 <listitem>
95 <para>The default udev rule would allow all users to access
96 <filename class='devicefile'>/dev/kvm</filename>. The editors
97 consider it dangerous. This option overrides it.</para>
98 </listitem>
99 </varlistentry>
100
101 <varlistentry>
102 <term><parameter>-Dlink-udev-shared=false</parameter></term>
103 <listitem>
104 <para>This option prevents udev from linking to the internal
105 systemd shared library,
106 <systemitem class='library'>libsystemd-shared</systemitem>.
107 This library is designed to be shared by many Systemd components
108 and it's too overkill for a udev-only installation.</para>
109 </listitem>
110 </varlistentry>
111 </variablelist>
112
113 <para>Only build the components needed for udev:</para>
114
115 <screen><userinput remap="make">ninja udevadm systemd-hwdb \
116 $(grep -o -E "^build (src/libudev|src/udev|rules.d|hwdb.d)[^:]*" \
117 build.ninja | awk '{ print $2 }') \
118 $(realpath libudev.so --relative-to .)</userinput></screen>
119
120 <para>Remove one udev rule file requiring a full Systemd
121 installation:</para>
122
123<screen><userinput remap="make">rm rules.d/90-vconsole.rules</userinput></screen>
124
125 <para>Install the package:</para>
126
127 <screen><userinput remap="install">install -vm755 -d {/usr/lib,/etc}/udev/{hwdb,rules}.d
128install -vm755 -d /usr/{lib,share}/pkgconfig
129install -vm755 udevadm /usr/bin/
130install -vm755 systemd-hwdb /usr/bin/udev-hwdb
131ln -svfn ../bin/udevadm /usr/sbin/udevd
132cp -av libudev.so{,*[0-9]} /usr/lib/
133install -vm644 ../src/libudev/libudev.h /usr/include/
134install -vm644 src/libudev/*.pc /usr/lib/pkgconfig/
135install -vm644 src/udev/*.pc /usr/share/pkgconfig/
136install -vm644 ../src/udev/udev.conf /etc/udev/
137install -vm644 rules.d/* ../rules.d/{*.rules,README} /usr/lib/udev/rules.d/
138install -vm644 hwdb.d/* ../hwdb.d/{*.hwdb,README} /usr/lib/udev/hwdb.d/
139install -vm755 $(find src/udev -type f | grep -F -v ".") /usr/lib/udev</userinput></screen>
140
141 <para>Install some custom rules and support files useful in an LFS
142 environment:</para>
143
144<screen><userinput remap="install">tar -xvf ../../&udev-lfs-version;.tar.xz
145make -f &udev-lfs-version;/Makefile.lfs install</userinput></screen>
146
147 <para>Install the man pages:</para>
148
149 <!-- Please make sure systemd man pages tarball has a common leading
150 component in the path. -->
151<screen><userinput remap="install">tar -xf ../../systemd-man-pages-&systemd-man-version;.tar.xz \
152 --no-same-owner --strip-components=1 \
153 -C /usr/share/man --wildcards '*/udev*' '*/libudev*' \
154 '*/systemd-'{hwdb,udevd.service}.8
155sed 's/systemd\(\\\?-\)/udev\1/' /usr/share/man/man8/systemd-hwdb.8 \
156 > /usr/share/man/man8/udev-hwdb.8
157sed 's|lib.*udevd|sbin/udevd|' \
158 /usr/share/man/man8/systemd-udevd.service.8 \
159 > /usr/share/man/man8/udevd.8
160rm /usr/share/man/man8/systemd-*.8</userinput></screen>
161
162 </sect2>
163
164 <sect2 id="conf-udev" role="configuration">
165 <title>Configuring Udev</title>
166
167 <indexterm zone="conf-udev">
168 <primary sortas="a-Udev">Udev</primary>
169 <secondary>configuring</secondary>
170 </indexterm>
171
172 <indexterm zone="conf-udev">
173 <primary sortas="e-/etc/udev/hwdb.bin">/etc/udev/hwdb.bin</primary>
174 </indexterm>
175
176 <para>Information about hardware devices is maintained in the
177 <filename class="directory">/etc/udev/hwdb.d</filename> and
178 <filename class="directory">/usr/lib/udev/hwdb.d</filename> directories.
179 <application>Udev</application> needs that information to be compiled
180 into a binary database <filename>/etc/udev/hwdb.bin</filename>. Create the
181 initial database:</para>
182
183<screen><userinput>udev-hwdb update</userinput></screen>
184
185 <para>This command needs to be run each time the hardware information is
186 updated.</para>
187
188 </sect2>
189
190 <sect2 id="contents-udev" role="content">
191 <title>Contents of Udev</title>
192
193 <segmentedlist>
194 <segtitle>Installed programs</segtitle>
195 <segtitle>Installed libraries</segtitle>
196 <segtitle>Installed directories</segtitle>
197
198 <seglistitem>
199 <seg>udevadm, udevd (symlink to udevadm), and udev-hwdb</seg>
200
201 <seg>libudev.so</seg>
202
203 <seg>/etc/udev and /usr/lib/udev</seg>
204 </seglistitem>
205 </segmentedlist>
206
207 <variablelist>
208 <bridgehead renderas="sect3">Short Descriptions</bridgehead>
209 <?dbfo list-presentation="list"?>
210 <?dbhtml list-presentation="table"?>
211 <varlistentry id="udevadm" revision="sysv">
212 <term><command>udevadm</command></term>
213 <listitem>
214 <para>Generic udev administration tool: controls the udevd daemon,
215 provides info from the Udev database, monitors uevents, waits for
216 uevents to finish, tests Udev configuration, and triggers uevents
217 for a given device</para>
218 <indexterm zone="ch-system-udev udevadm">
219 <primary sortas="b-udevadm">udevadm</primary>
220 </indexterm>
221 </listitem>
222 </varlistentry>
223
224 <varlistentry id="udevd">
225 <term><command>udevd</command></term>
226 <listitem>
227 <para>A daemon that listens for uevents on the netlink socket,
228 creates devices and runs the configured external programs in
229 response to these uevents</para>
230 <indexterm zone="ch-system-udev udevd">
231 <primary sortas="b-udevd">udevd</primary>
232 </indexterm>
233 </listitem>
234 </varlistentry>
235
236 <varlistentry id="udev-hwdb">
237 <term><command>udev-hwdb</command></term>
238 <listitem>
239 <para>Updates or queries the hardware database.</para>
240 <indexterm zone="ch-system-udev udev-hwdb">
241 <primary sortas="b-udev-hwdb">udev-hwdb</primary>
242 </indexterm>
243 </listitem>
244 </varlistentry>
245
246 <varlistentry id="libudev">
247 <term><filename class="libraryfile">libudev</filename></term>
248 <listitem>
249 <para>A library interface to udev device information</para>
250 <indexterm zone="ch-system-udev libudev">
251 <primary sortas="c-libudev">libudev</primary>
252 </indexterm>
253 </listitem>
254 </varlistentry>
255
256 <varlistentry id="etc-udev">
257 <term><filename class="directory">/etc/udev</filename></term>
258 <listitem>
259 <para>Contains Udev configuration files,
260 device permissions, and rules for device naming</para>
261 <indexterm zone="ch-system-udev etc-udev">
262 <primary sortas="e-/etc/udev">/etc/udev</primary>
263 </indexterm>
264 </listitem>
265 </varlistentry>
266
267 </variablelist>
268
269 </sect2>
270
271</sect1>
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