chroot.xml 3.0 KB

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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. <sect1 id="ch-system-chroot">
  8. <?dbhtml filename="chroot.html"?>
  9. <title>Entering the Chroot Environment</title>
  10. <para>It is time to enter the chroot environment to begin building and
  11. installing the final LFS system. As user <systemitem
  12. class="username">root</systemitem>, run the following command to enter the
  13. realm that is, at the moment, populated with only the temporary tools:</para>
  14. <screen role="nodump"><userinput>chroot "$LFS" /tools/bin/env -i \
  15. HOME=/root \
  16. TERM="$TERM" \
  17. PS1='(lfs chroot) \u:\w\$ ' \
  18. PATH=/bin:/usr/bin:/sbin:/usr/sbin:/tools/bin \
  19. /tools/bin/bash --login +h</userinput></screen>
  20. <para>The <parameter>-i</parameter> option given to the <command>env</command>
  21. command will clear all variables of the chroot environment. After that, only
  22. the <envar>HOME</envar>, <envar>TERM</envar>, <envar>PS1</envar>, and
  23. <envar>PATH</envar> variables are set again. The
  24. <parameter>TERM=$TERM</parameter> construct will set the <envar>TERM</envar>
  25. variable inside chroot to the same value as outside chroot. This variable is
  26. needed for programs like <command>vim</command> and <command>less</command>
  27. to operate properly. If other variables are needed, such as
  28. <envar>CFLAGS</envar> or <envar>CXXFLAGS</envar>, this is a good place to set
  29. them again.</para>
  30. <para>From this point on, there is no need to use the
  31. <envar>LFS</envar> variable anymore, because all work will be restricted
  32. to the LFS file system. This is because the Bash shell is told that
  33. <filename class="directory">$LFS</filename> is now the root
  34. (<filename class="directory">/</filename>) directory.</para>
  35. <para>Notice that <filename class="directory">/tools/bin</filename> comes last
  36. in the <envar>PATH</envar>. This means that a temporary tool will no longer be
  37. used once its final version is installed. This occurs when the shell does not
  38. <quote>remember</quote> the locations of executed binaries&mdash;for this
  39. reason, hashing is switched off by passing the <parameter>+h</parameter> option
  40. to <command>bash</command>.</para>
  41. <para>Note that the <command>bash</command> prompt will say
  42. <computeroutput>I have no name!</computeroutput> This is normal because the
  43. <filename>/etc/passwd</filename> file has not been created yet.</para>
  44. <note>
  45. <para>It is important that all the commands throughout the remainder of this
  46. chapter and the following chapters are run from within the chroot
  47. environment. If you leave this environment for any reason (rebooting for
  48. example), ensure that the virtual kernel filesystems are mounted as
  49. explained in <xref linkend="ch-system-bindmount"/> and <xref
  50. linkend="ch-system-kernfsmount"/> and enter chroot again before continuing
  51. with the installation.</para>
  52. </note>
  53. </sect1>