| 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-chroot-kernfs">
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| 9 | <?dbhtml filename="kernfs.html"?>
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| 10 |
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| 11 | <title>Mounting Virtual Kernel File Systems</title>
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| 12 |
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| 13 | <xi:include xmlns:xi="http://www.w3.org/2003/XInclude"
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| 14 | href="../../boot/common/devices.xml"
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| 15 | xpointer="xpointer(//*[@os='a'])"/>
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| 16 |
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| 17 | <para>Various file systems exported by the kernel are used to communicate
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| 18 | to and from the kernel itself. These file systems are virtual in that no
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| 19 | disk space is used for them. The content of the file systems resides in
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| 20 | memory.</para>
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| 21 |
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| 22 | <para>Begin by creating directories onto which the file systems will
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| 23 | be mounted:</para>
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| 24 |
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| 25 | <screen><userinput>mkdir -pv $CLFS/{dev,proc,sys}</userinput></screen>
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| 26 |
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| 27 | <para>Now mount the file systems:</para>
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| 28 |
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| 29 | <screen><userinput>mount -vt proc proc $CLFS/proc
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| 30 | mount -vt sysfs sysfs $CLFS/sys</userinput></screen>
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| 31 |
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| 32 | <para>Remember that if for any reason you stop working on the CLFS system
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| 33 | and start again later, it is important to check that these file systems
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| 34 | are mounted again before entering the chroot environment.</para>
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| 35 |
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| 36 | <para>Two device nodes, /dev/console and /dev/null, are required to be
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| 37 | present on the filesystem. These are needed by the kernel even before
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| 38 | starting Udev early in the boot process, so we create them here:</para>
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| 39 |
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| 40 | <screen><userinput>mknod -m 600 $CLFS/dev/console c 5 1
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| 41 | mknod -m 666 $CLFS/dev/null c 1 3</userinput></screen>
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| 42 |
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| 43 | <para>Once the system is complete and booting, the rest of our device
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| 44 | nodes are created by the Udev package. Since this package is not
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| 45 | available to us right now, we must take other steps to provide device
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| 46 | nodes under on the CLFS filesystem. We will use the <quote>bind</quote>
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| 47 | option in the mount command to make our host system's /dev structure
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| 48 | appear in the new CLFS filesystem:</para>
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| 49 |
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| 50 | <screen><userinput>mount -v -o bind /dev $CLFS/dev</userinput></screen>
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| 51 |
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| 52 | <para>Additional file systems will soon be mounted from within the chroot
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| 53 | environment. To keep the host up to date, perform a <quote>fake mount</quote>
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| 54 | for each of these now:</para>
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| 55 |
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| 56 | <screen><userinput>mount -f -vt tmpfs tmpfs $CLFS/dev/shm
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| 57 | mount -f -vt devpts -o gid=4,mode=620 devpts $CLFS/dev/pts</userinput></screen>
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| 58 |
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| 59 | </sect1>
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