[9dfc02f] | 1 | <?xml version="1.0" encoding="ISO-8859-1"?>
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[1770019] | 2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
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[9dfc02f] | 3 | <!ENTITY % general-entities SYSTEM "../general.ent">
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| 4 | %general-entities;
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| 5 | ]>
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[81fd230] | 6 | <sect1 id="ch-system-devices">
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[4f74577] | 7 | <title>Populating /dev</title>
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[9dfc02f] | 8 | <?dbhtml filename="devices.html"?>
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| 9 |
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[32b21a1] | 10 | <indexterm zone="ch-system-devices"><primary sortas="e-/dev/">/dev/*</primary></indexterm>
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[81fd230] | 11 |
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| 12 | <sect2>
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| 13 | <title>Creating Initial Device Nodes</title>
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| 14 |
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| 15 | <para>When the kernel boots the system, it requires the presence of a few device
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| 16 | nodes, in particular the <filename class="devicefile">console</filename> and
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| 17 | <filename class="devicefile">null</filename> devices. Create these by
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| 18 | running the following commands:</para>
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[9dfc02f] | 19 |
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| 20 | <screen><userinput>mknod -m 600 /dev/console c 5 1
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| 21 | mknod -m 666 /dev/null c 1 3</userinput></screen>
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[81fd230] | 22 | </sect2>
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| 23 |
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| 24 | <sect2>
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| 25 | <title>Mounting ramfs and Populating /dev</title>
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[9dfc02f] | 26 |
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[373a708] | 27 | <para>The recommended method of populating the <filename
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| 28 | class="directory">/dev</filename> directory with devices is to mount a virtual
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| 29 | filesystem (such as <systemitem class="filesystem">ramfs</systemitem> or
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| 30 | <systemitem class="filesystem">tmpfs</systemitem>) on the <filename
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| 31 | class="directory">/dev</filename> directory, and allow the devices to be created
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| 32 | dynamically on that virtual filesystem as they are detected or accessed. This is
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| 33 | generally done during the boot process. Since this new system has not been
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| 34 | booted, it is necessary to do what the bootscripts would otherwise do by
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| 35 | mounting <filename class="directory">/dev</filename>:</para>
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[9dfc02f] | 36 |
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| 37 | <screen><userinput>mount -n -t ramfs none /dev</userinput></screen>
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| 38 |
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[373a708] | 39 | <para>The Udev package is what actually creates the devices in the <filename
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| 40 | class="directory">/dev</filename> directory. Since it will not be installed
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| 41 | until later on in the process, manually create the minimal set of device nodes
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| 42 | needed to complete the building of this system:</para>
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[9dfc02f] | 43 |
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[0a9b2e0] | 44 | <screen><userinput>mknod -m 622 /dev/console c 5 1
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| 45 | mknod -m 666 /dev/null c 1 3
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| 46 | mknod -m 666 /dev/zero c 1 5
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| 47 | mknod -m 666 /dev/ptmx c 5 2
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[84dee3b4] | 48 | mknod -m 666 /dev/tty c 5 0
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| 49 | mknod -m 444 /dev/random c 1 8
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| 50 | mknod -m 444 /dev/urandom c 1 9
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| 51 | chown root:tty /dev/{console,ptmx,tty}</userinput></screen>
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[81fd230] | 52 | <!-- -->
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[9dfc02f] | 53 |
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[81fd230] | 54 | <para>There are some symlinks and directories required by LFS that are
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| 55 | not created by Udev, so create those here:</para>
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[9dfc02f] | 56 |
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| 57 | <screen><userinput>ln -s /proc/self/fd /dev/fd
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| 58 | ln -s /proc/self/fd/0 /dev/stdin
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| 59 | ln -s /proc/self/fd/1 /dev/stdout
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| 60 | ln -s /proc/self/fd/2 /dev/stderr
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| 61 | ln -s /proc/kcore /dev/core
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| 62 | mkdir /dev/pts
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| 63 | mkdir /dev/shm</userinput></screen>
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| 64 |
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[81fd230] | 65 | <para>Finally, mount the proper virtual (kernel) file systems on the
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| 66 | newly-created directories:</para>
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[9dfc02f] | 67 |
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| 68 | <screen><userinput>mount -t devpts -o gid=4,mode=620 none /dev/pts
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| 69 | mount -t tmpfs none /dev/shm</userinput></screen>
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[af133c3] | 70 |
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[81fd230] | 71 | <para>The <command>mount</command> commands executed above may result
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| 72 | in the following warning message:</para>
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| 73 |
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| 74 | <screen><computeroutput>can't open /etc/fstab: No such file or directory.</computeroutput></screen>
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| 75 |
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| 76 | <para>This file—<filename>/etc/fstab</filename>—has not
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| 77 | been created yet but is also not required for the file systems to be
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| 78 | properly mounted. As such, the warning can be safely ignored.</para>
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| 79 | </sect2>
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[9dfc02f] | 80 |
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| 81 | </sect1>
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[81fd230] | 82 |
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