[9dfc02f] | 1 | <?xml version="1.0" encoding="ISO-8859-1"?>
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[fa994c9] | 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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[9dfc02f] | 4 | <!ENTITY % general-entities SYSTEM "../general.ent">
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| 5 | %general-entities;
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| 6 | ]>
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[fa994c9] | 7 |
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[81fd230] | 8 | <sect1 id="ch-system-devices">
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[fa994c9] | 9 | <?dbhtml filename="devices.html"?>
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| 10 |
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| 11 | <title>Populating /dev</title>
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[9dfc02f] | 12 |
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[fa994c9] | 13 | <indexterm zone="ch-system-devices">
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| 14 | <primary sortas="e-/dev/">/dev/*</primary>
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| 15 | </indexterm>
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[81fd230] | 16 |
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[fa994c9] | 17 | <sect2>
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| 18 | <title>Creating Initial Device Nodes</title>
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[81fd230] | 19 |
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[fa994c9] | 20 | <para>When the kernel boots the system, it requires the presence of a few
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| 21 | device nodes, in particular the <filename class="devicefile">console</filename>
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| 22 | and <filename class="devicefile">null</filename> devices. The device nodes
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| 23 | will be created on the hard disk so that they are available before
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| 24 | <command>udev</command> has been started, and additionally when Linux is
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| 25 | started in single user mode (hence the restrictive permissions on
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| 26 | <filename class="devicefile">console</filename>). Create the devices by
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| 27 | running the following commands:</para>
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[9dfc02f] | 28 |
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| 29 | <screen><userinput>mknod -m 600 /dev/console c 5 1
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| 30 | mknod -m 666 /dev/null c 1 3</userinput></screen>
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[81fd230] | 31 |
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[fa994c9] | 32 | </sect2>
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| 33 |
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| 34 | <sect2>
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| 35 | <title>Mounting tmpfs and Populating /dev</title>
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[9dfc02f] | 36 |
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[fa994c9] | 37 | <para>The recommended method of populating the <filename
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| 38 | class="directory">/dev</filename> directory with devices is to mount a
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| 39 | virtual filesystem (such as <systemitem class="filesystem">tmpfs</systemitem>)
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| 40 | on the <filename class="directory">/dev</filename> directory, and allow the
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| 41 | devices to be created dynamically on that virtual filesystem as they are
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| 42 | detected or accessed. This is generally done during the boot process. Since
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| 43 | this new system has not been booted, it is necessary to do what the
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| 44 | LFS-Bootscripts package would otherwise do by mounting <filename
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| 45 | class="directory">/dev</filename>:</para>
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[9dfc02f] | 46 |
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[5998892] | 47 | <screen><userinput>mount -nvt tmpfs none /dev</userinput></screen>
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[9dfc02f] | 48 |
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[fa994c9] | 49 | <para>The Udev package is what actually creates the devices in the <filename
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| 50 | class="directory">/dev</filename> directory. Since it will not be installed
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| 51 | until later on in the process, manually create the minimal set of device nodes
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| 52 | needed to complete the building of this system:</para>
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[9dfc02f] | 53 |
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[0a9b2e0] | 54 | <screen><userinput>mknod -m 622 /dev/console c 5 1
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| 55 | mknod -m 666 /dev/null c 1 3
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| 56 | mknod -m 666 /dev/zero c 1 5
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| 57 | mknod -m 666 /dev/ptmx c 5 2
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[84dee3b4] | 58 | mknod -m 666 /dev/tty c 5 0
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| 59 | mknod -m 444 /dev/random c 1 8
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| 60 | mknod -m 444 /dev/urandom c 1 9
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[5998892] | 61 | chown -v root:tty /dev/{console,ptmx,tty}</userinput></screen>
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[9dfc02f] | 62 |
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[fa994c9] | 63 | <para>There are some symlinks and directories required by LFS that are
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| 64 | created during system startup by the LFS-Bootscripts package. Since this
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| 65 | is a chroot environment and not a booted environment, those symlinks and
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| 66 | directories need to be created here:</para>
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[9dfc02f] | 67 |
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[5998892] | 68 | <screen><userinput>ln -sv /proc/self/fd /dev/fd
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| 69 | ln -sv /proc/self/fd/0 /dev/stdin
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| 70 | ln -sv /proc/self/fd/1 /dev/stdout
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| 71 | ln -sv /proc/self/fd/2 /dev/stderr
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| 72 | ln -sv /proc/kcore /dev/core
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| 73 | mkdir -v /dev/pts
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| 74 | mkdir -v /dev/shm</userinput></screen>
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[9dfc02f] | 75 |
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[fa994c9] | 76 | <para>Finally, mount the proper virtual (kernel) file systems on the
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| 77 | newly-created directories:</para>
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[9dfc02f] | 78 |
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[5998892] | 79 | <screen><userinput>mount -vt devpts -o gid=4,mode=620 none /dev/pts
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| 80 | mount -vt tmpfs none /dev/shm</userinput></screen>
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[af133c3] | 81 |
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[fa994c9] | 82 | <para>The <command>mount</command> commands executed above may result
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| 83 | in the following warning message:</para>
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[81fd230] | 84 |
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| 85 | <screen><computeroutput>can't open /etc/fstab: No such file or directory.</computeroutput></screen>
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| 86 |
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[fa994c9] | 87 | <para>This file—<filename>/etc/fstab</filename>—has not
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| 88 | been created yet but is also not required for the file systems to be
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| 89 | properly mounted. As such, the warning can be safely ignored.</para>
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[9dfc02f] | 90 |
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[fa994c9] | 91 | </sect2>
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[81fd230] | 92 |
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[fa994c9] | 93 | </sect1>
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