| 1 | <?xml version="1.0" encoding="ISO-8859-1"?>
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| 2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
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| 3 | <!ENTITY % general-entities SYSTEM "../general.ent">
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| 4 | %general-entities;
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| 5 | ]>
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| 6 | <sect1 id="ch-system-chroot">
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| 7 | <title>Entering the Chroot Environment</title>
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| 8 | <?dbhtml filename="chroot.html"?>
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| 9 |
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| 10 | <para>It is time to enter the chroot environment to begin
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| 11 | building and installing the final LFS system. As user
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| 12 | <emphasis>root</emphasis>, run the following command to enter the
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| 13 | realm that is, at the moment, populated with only the temporary
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| 14 | tools:</para>
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| 15 |
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| 16 | <screen><userinput>chroot "$LFS" /tools/bin/env -i \
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| 17 | HOME=/root TERM="$TERM" PS1='\u:\w\$ ' \
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| 18 | PATH=/bin:/usr/bin:/sbin:/usr/sbin:/tools/bin \
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| 19 | /tools/bin/bash --login +h</userinput></screen>
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| 20 |
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| 21 | <para>The <parameter>-i</parameter> option given to the
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| 22 | <command>env</command> command will clear all variables of the chroot
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| 23 | environment. After that, only the <emphasis>HOME</emphasis>,
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| 24 | <emphasis>TERM</emphasis>, <emphasis>PS1</emphasis>, and
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| 25 | <emphasis>PATH</emphasis> variables are set again. The
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| 26 | <parameter>TERM=$TERM</parameter> construct will set the
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| 27 | <emphasis>TERM</emphasis> variable inside chroot to the same value as
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| 28 | outside chroot. This variable is needed for programs like
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| 29 | <command>vim</command> and <command>less</command> to operate
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| 30 | properly. If other variables are needed, such as
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| 31 | <emphasis>CFLAGS</emphasis> or <emphasis>CXXFLAGS</emphasis>, this is
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| 32 | a good place to set them again.</para>
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| 33 |
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| 34 | <para>From this point on, there is no need to use the
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| 35 | <emphasis>LFS</emphasis> variable anymore, because all work will be
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| 36 | restricted to the LFS file system. This is because the Bash shell is
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| 37 | told that <filename class="directory">$LFS</filename> is now the root
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| 38 | (<filename class="directory">/</filename>) directory.</para>
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| 39 |
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| 40 | <para>Notice that <filename class="directory">/tools/bin</filename> comes last in the PATH. This means that a
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| 41 | temporary tool will not be used anymore as soon as its final version
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| 42 | is installed. This occurs when the shell does not <quote>remember</quote> the
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| 43 | locations of executed binaries—for this reason, hashing is switched
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| 44 | off by passing the +h option to bash.</para>
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| 45 |
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| 46 | <para>It is important that all the commands throughout the remainder
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| 47 | of this chapter and the following chapters be run from within the
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| 48 | chroot environment. If you leave this environment for any reason
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| 49 | (rebooting for example), remember to first mount the <systemitem
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| 50 | class="filesystem">proc</systemitem> and <systemitem
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| 51 | class="filesystem">devpts</systemitem> file systems (discussed in the
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| 52 | previous section) and enter chroot again before continuing with the
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| 53 | installations.</para>
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| 54 |
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| 55 | <para>Note that the bash prompt will say <quote>I have no
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| 56 | name!</quote> This is normal because the
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| 57 | <filename>/etc/passwd</filename> file has not been created yet.</para>
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| 58 |
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| 59 | </sect1>
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| 60 |
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