1 | <?xml version="1.0" encoding="ISO-8859-1"?>
|
---|
2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
|
---|
3 | <!ENTITY % general-entities SYSTEM "../general.ent">
|
---|
4 | %general-entities;
|
---|
5 | ]>
|
---|
6 | <sect1 id="ch-system-devices" xreflabel="devices">
|
---|
7 | <title>Populating /dev</title>
|
---|
8 | <?dbhtml filename="devices.html"?>
|
---|
9 |
|
---|
10 | <indexterm zone="ch-system-devices"><primary sortas="e-Devices">Devices</primary></indexterm>
|
---|
11 |
|
---|
12 | <sect2>
|
---|
13 | <title>Creating initial device nodes</title>
|
---|
14 |
|
---|
15 | <para>When the kernel boots the system, it requires the presence of a few device
|
---|
16 | nodes, in particular the <filename class="devicefile">console</filename> and
|
---|
17 | <filename class="devicefile">null</filename> devices:</para>
|
---|
18 |
|
---|
19 | <screen><userinput>mknod -m 600 /dev/console c 5 1
|
---|
20 | mknod -m 666 /dev/null c 1 3</userinput></screen>
|
---|
21 | </sect2>
|
---|
22 |
|
---|
23 | <sect2>
|
---|
24 | <title>Mounting ramfs and populating /dev</title>
|
---|
25 |
|
---|
26 | <para>The ideal way to populate <filename class="directory">/dev</filename> is
|
---|
27 | to mount a <systemitem class="filesystem">ramfs</systemitem> onto <filename class="directory">/dev </filename>
|
---|
28 | like <systemitem class="filesystem">tmpfs</systemitem>, but it
|
---|
29 | cannot be swapped) and create the devices on there during each bootup. Since we haven't
|
---|
30 | booted the system, we have to do what the bootscripts would otherwise do for us, and
|
---|
31 | populate <filename class="directory">/dev</filename> ourselves. Begin by mounting <filename class="directory">/dev</filename>:</para>
|
---|
32 |
|
---|
33 | <screen><userinput>mount -n -t ramfs none /dev</userinput></screen>
|
---|
34 |
|
---|
35 | <para>Since we do not have the Udev package installed yet, we'll create a
|
---|
36 | minimal set of device nodes to use for building:</para>
|
---|
37 |
|
---|
38 | <screen><userinput>mknod -m 622 /dev/console c 5 1
|
---|
39 | mknod -m 666 /dev/null c 1 3
|
---|
40 | mknod -m 666 /dev/zero c 1 5
|
---|
41 | mknod -m 666 /dev/ptmx c 5 2
|
---|
42 | mknod -m 666 /dev/tty c 5 0
|
---|
43 | mknod -m 444 /dev/random c 1 8
|
---|
44 | mknod -m 444 /dev/urandom c 1 9
|
---|
45 | chown root:tty /dev/{console,ptmx,tty}</userinput></screen>
|
---|
46 |
|
---|
47 | <para>There are some symlinks and directories required by LFS that are not created by
|
---|
48 | Udev, so we create those ourselves here:</para>
|
---|
49 |
|
---|
50 | <screen><userinput>ln -s /proc/self/fd /dev/fd
|
---|
51 | ln -s /proc/self/fd/0 /dev/stdin
|
---|
52 | ln -s /proc/self/fd/1 /dev/stdout
|
---|
53 | ln -s /proc/self/fd/2 /dev/stderr
|
---|
54 | ln -s /proc/kcore /dev/core
|
---|
55 | mkdir /dev/pts
|
---|
56 | mkdir /dev/shm</userinput></screen>
|
---|
57 |
|
---|
58 | <para>Finally, mount the proper virtual (kernel) file systems on the directories we just
|
---|
59 | created:</para>
|
---|
60 |
|
---|
61 | <screen><userinput>mount -t devpts -o gid=4,mode=620 none /dev/pts
|
---|
62 | mount -t tmpfs none /dev/shm</userinput></screen>
|
---|
63 |
|
---|
64 | <para>The <command>mount</command> commands executed above may result in the
|
---|
65 | following warning message:</para>
|
---|
66 |
|
---|
67 | <screen><computeroutput>can't open /etc/fstab: No such file or directory.</computeroutput></screen>
|
---|
68 |
|
---|
69 | <para>This file—<filename>/etc/fstab</filename>—has not
|
---|
70 | been created yet but is also not required for the file systems to be
|
---|
71 | properly mounted. As such, the warning can be safely ignored.</para>
|
---|
72 | </sect2>
|
---|
73 |
|
---|
74 |
|
---|
75 | </sect1>
|
---|