1 | <?xml version="1.0" encoding="ISO-8859-1"?>
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2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
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3 | <!ENTITY % general-entities SYSTEM "../general.ent">
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4 | %general-entities;
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5 | ]>
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6 | <sect1 id="ch-system-devices" xreflabel="devices">
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7 | <title>Populating /dev</title>
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8 | <?dbhtml filename="devices.html"?>
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9 |
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10 | <indexterm zone="ch-system-devices"><primary sortas="e-Devices">Devices</primary></indexterm>
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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:</para>
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18 |
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19 | <screen><userinput>mknod -m 600 /dev/console c 5 1
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20 | mknod -m 666 /dev/null c 1 3</userinput></screen>
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21 | </sect2>
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22 |
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23 | <sect2>
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24 | <title>Mounting ramfs and populating /dev</title>
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25 |
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26 | <para>The ideal way to populate <filename class="directory">/dev</filename> is
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27 | to mount a <systemitem class="filesystem">ramfs</systemitem> onto <filename class="directory">/dev </filename>
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28 | like <systemitem class="filesystem">tmpfs</systemitem>, but it
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29 | cannot be swapped) and create the devices on there during each bootup. Since we haven't
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30 | booted the system, we have to do what the bootscripts would otherwise do for us, and
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31 | populate <filename class="directory">/dev</filename> ourselves. Begin by mounting <filename class="directory">/dev</filename>:</para>
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32 |
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33 | <screen><userinput>mount -n -t ramfs none /dev</userinput></screen>
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34 |
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35 | <para>Now use the provided udevstart utility to create the initial devices based on
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36 | all the information in <filename class="directory">/sys</filename>:</para>
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37 |
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38 | <screen><userinput>/tools/sbin/udevstart</userinput></screen>
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39 |
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40 | <para>There are some symlinks and directories required by LFS that are not created by
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41 | Udev, so we create those ourselves here:</para>
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42 |
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43 | <screen><userinput>ln -s /proc/self/fd /dev/fd
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44 | ln -s /proc/self/fd/0 /dev/stdin
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45 | ln -s /proc/self/fd/1 /dev/stdout
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46 | ln -s /proc/self/fd/2 /dev/stderr
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47 | ln -s /proc/kcore /dev/core
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48 | mkdir /dev/pts
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49 | mkdir /dev/shm</userinput></screen>
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50 |
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51 | <para>Finally, mount the proper virtual (kernel) file systems on the directories we just
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52 | created:</para>
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53 |
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54 | <screen><userinput>mount -t devpts -o gid=4,mode=620 none /dev/pts
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55 | mount -t tmpfs none /dev/shm</userinput></screen>
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56 | </sect2>
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57 |
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58 |
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59 | </sect1>
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