source: BOOK/chroot/x86/before-chroot.xml@ 72815fe

clfs-2.1 clfs-3.0.0-systemd clfs-3.0.0-sysvinit systemd sysvinit
Last change on this file since 72815fe was 9d5337b, checked in by Chris Staub <chris@…>, 16 years ago

Text cleanup on the before-chroot page

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[42a32ea]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-chroot-before-chroot">
9 <?dbhtml filename="before-chroot.html"?>
10 <title>Before Entering the Chroot Environment</title>
11
12 <sect2 role="determining-ifneeded">
13 <title>Determining if steps need to be taken</title>
14
15 <para>Before we can enter the chroot we have to make sure that the system is
16 in the proper state. From this point on the <envar>${CLFS_TARGET}</envar>
[9d5337b]17 environment variable will no longer exist, so it will have no bearing on the
18 rest of the book - most packages will rely on
[42a32ea]19 <command>config.guess</command> provided by
20 <xref linkend="ch-system-automake"/>. Packages that do not use autotools
[9d5337b]21 either do not care about the target triplet, or have their own means
22 of determining its value.</para>
[42a32ea]23
[9d5337b]24 <para>In both cases, the information about the host cpu used to determine
[42a32ea]25 the target triplet is gathered from the same place,
26 <command>uname -m</command>. Executing this command outside of the chroot
[9d5337b]27 as well as inside the chroot will have the exact same output.</para>
[42a32ea]28
[9d5337b]29 <para>If you're unsure if your host and target have the same target
30 triplet, you can use this test to determine what the host's target triplet
[42a32ea]31 is and if you need to take any steps to ensure that you don't build for the
32 wrong architecture. Extract the <xref linkend="ch-system-automake"/> tarball
33 and <command>cd</command> into the created directory. Then execute the
[9d5337b]34 following to see what the detected target triplet is by
35 <command>config.guess</command>:</para>
[42a32ea]36
37<screen><userinput>lib/config.guess</userinput></screen>
38
39 <para>If the output of that command does not equal what is in
40 <envar>${CLFS_TARGET}</envar> then you need to read on. If it does then you
41 can safely continue onto <xref linkend="ch-chroot-chroot"/>.</para>
42
43 </sect2>
44
45 <sect2 role="using-setarch">
46 <title>Using Setarch</title>
47
48 <para>If your host has a tool called <command>setarch</command> this may
49 solve your problems. The reason for saying may is because on a architecture
50 such as x86_64, using <command>setarch linux32 uname -m</command> will only
51 ever output i686. It is not possible to get an output of i486 or i586.</para>
52
53 <para>To test if setarch does everything you need it to, execute the
[9d5337b]54 following command from inside the <xref linkend="ch-system-automake"/>
[42a32ea]55 directory:</para>
56
57<screen><userinput>setarch linux32 lib/config.guess</userinput></screen>
58
59 <para>If the output of the command above equals what is in
60 <envar>${CLFS_TARGET}</envar> then you have a viable solution. You can
61 wrap the chroot command on the next page with
62 <command>setarch linux32</command>. It will look like the following:</para>
63
64<screen><userinput>setarch linux32 chroot "${CLFS}" /tools/bin/env -i \
65 HOME=/root TERM="${TERM}" PS1='\u:\w\$ ' \
66 PATH=/bin:/usr/bin:/sbin:/usr/sbin:/tools/bin \
67 /tools/bin/bash --login +h</userinput></screen>
68
69 <para>If setarch works for you then you can safely continue onto
70 <xref linkend="ch-chroot-chroot"/>. If not, there is one more option
71 covered in this book.</para>
72
73 </sect2>
74
75 <sect2 role="using-uname_hack">
76 <title>Using a Uname Hack</title>
77
78 <para os="uua">The Uname Hack is a kernel module that modifies the output of
79 <command>uname -m</command> by directly changing the value of the
80 detected machine type. The kernel module will save the original value
81 and restore it when the module is unloaded.</para>
82
83 <variablelist os="uub" role="materials">
84 <varlistentry>
85 <term>Uname Hack (&uname_hack-version;) - &uname_hack-size;:</term>
86
87 <listitem>
88 <para>Home page: <ulink url="&uname_hack-home;"/></para>
89 <para>Download: <ulink url="&uname_hack-url;"/></para>
90 <para>MD5 sum: <literal>&uname_hack-md5;</literal></para>
91 </listitem>
92 </varlistentry>
93 </variablelist>
94
95 <para os="uuc">Extract the tarball and <command>cd</command> into the
96 created directory. To build the Uname Hack you must have the kernel sources
[9d5337b]97 for your currently running kernel available. Build the Uname Hack with the
[42a32ea]98 following or similar command:</para>
99
100<screen os="uud"><userinput>make uname_hack_fake_machine=i486</userinput></screen>
101
[bba53b5]102 <variablelist os="uue">
103 <title>The meaning of the make and install options:</title>
104
105 <varlistentry os="uue1">
106 <term><parameter>uname_hack_fake_machine=i486</parameter></term>
107 <listitem>
108 <para>This parameter sets the value that the uts machine type will be
[9d5337b]109 changed to. Alternatively this could be set to i586 or i686.</para>
[bba53b5]110 </listitem>
111 </varlistentry>
112
113 </variablelist>
114
[9d5337b]115 <para os="uuf">In the top level directory of the Uname Hack package you
116 should see a file named <filename>uname_hack.ko</filename>. As soon as
117 that module is loaded into the running kernel the output of
118 <command>uname -m</command> will be affected immediately system-wide.
119 Load the kernel module with the following command:</para>
[42a32ea]120
[bba53b5]121<screen os="uug"><userinput>insmod uname_hack.ko</userinput></screen>
[42a32ea]122
[bba53b5]123 <para os="uuh">To test if the Uname Hack is working properly, execute the
[9d5337b]124 following command from inside the <xref linkend="ch-system-automake"/>
[42a32ea]125 directory:</para>
126
[bba53b5]127<screen os="uui"><userinput>lib/config.guess</userinput></screen>
[42a32ea]128
[bba53b5]129 <para os="uuj">The output of the above command should be the same as the
[9d5337b]130 <envar>${CLFS_TARGET}</envar> environment variable. If this is not the
131 case, you can try and get help on the CLFS Support Mailing List or the
[42a32ea]132 IRC Channel. See <xref linkend="ch-intro-askforhelp"/> for more
133 information.</para>
134
135 </sect2>
136
137</sect1>
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