| 1 | <?xml version="1.0" encoding="ISO-8859-1"?>
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| 2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
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| 3 | "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
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| 4 | <!ENTITY % general-entities SYSTEM "../general.ent">
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| 5 | %general-entities;
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| 6 | ]>
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| 7 |
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| 8 | <sect1 id="ch-system-chroot">
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| 9 | <?dbhtml filename="chroot.html"?>
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| 10 |
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| 11 | <title>Entering the Chroot Environment</title>
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| 12 |
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| 13 | <para>It is time to enter the chroot environment to begin building and
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| 14 | installing the final LFS system. As user <systemitem
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| 15 | class="username">root</systemitem>, run the following command to enter the
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| 16 | realm that is, at the moment, populated with only the temporary tools:</para>
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| 17 |
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| 18 | <screen><userinput>chroot "$LFS" /tools/bin/env -i \
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| 19 | HOME=/root TERM="$TERM" PS1='\u:\w\$ ' \
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| 20 | PATH=/bin:/usr/bin:/sbin:/usr/sbin:/tools/bin \
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| 21 | /tools/bin/bash --login +h</userinput></screen>
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| 22 |
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| 23 | <para>The <parameter>-i</parameter> option given to the <command>env</command>
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| 24 | command will clear all variables of the chroot environment. After that, only
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| 25 | the <envar>HOME</envar>, <envar>TERM</envar>, <envar>PS1</envar>, and
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| 26 | <envar>PATH</envar> variables are set again. The
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| 27 | <parameter>TERM=$TERM</parameter> construct will set the <envar>TERM</envar>
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| 28 | variable inside chroot to the same value as outside chroot. This variable is
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| 29 | needed for programs like <command>vim</command> and <command>less</command>
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| 30 | to operate properly. If other variables are needed, such as
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| 31 | <envar>CFLAGS</envar> or <envar>CXXFLAGS</envar>, this is a good place to set
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| 32 | them again.</para>
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| 33 |
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| 34 | <para>From this point on, there is no need to use the
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| 35 | <envar>LFS</envar> variable anymore, because all work will be restricted
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| 36 | to the LFS file system. This is because the Bash shell is told that
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| 37 | <filename class="directory">$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
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| 41 | in the <envar>PATH</envar>. This means that a temporary tool will no longer be
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| 42 | used once its final version is installed. This occurs when the shell does not
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| 43 | <quote>remember</quote> the locations of executed binaries—for this
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| 44 | reason, hashing is switched off by passing the <parameter>+h</parameter> option
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| 45 | to <command>bash</command>.</para>
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| 46 |
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| 47 | <para>It is important that all the commands throughout the remainder of this
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| 48 | chapter and the following chapters are run from within the chroot environment.
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| 49 | If you leave this environment for any reason (rebooting for example), remember
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| 50 | to first mount the <systemitem class="filesystem">proc</systemitem> and
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| 51 | <systemitem class="filesystem">devpts</systemitem> file systems (discussed
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| 52 | in the 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 <command>bash</command> prompt will say
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| 56 | <computeroutput>I have no name!</computeroutput> 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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