source: chapter06/createfiles.xml@ ca2f2b4e

7.9-systemd 7.9-systemd-rc1 7.9-systemd-rc2 systemd
Last change on this file since ca2f2b4e was ca2f2b4e, checked in by Krejzi <krejzi@…>, 6 years ago

Add new user/group required by systemd-229.

git-svn-id: http://svn.linuxfromscratch.org/LFS/branches/systemd@11005 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

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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
8<sect1 id="ch-system-createfiles">
9 <?dbhtml filename="createfiles.html"?>
10
11 <title>Creating Essential Files and Symlinks</title>
12
13 <indexterm zone="ch-system-createfiles">
14 <primary sortas="e-/etc/passwd">/etc/passwd</primary>
15 </indexterm>
16
17 <indexterm zone="ch-system-createfiles">
18 <primary sortas="e-/etc/group">/etc/group</primary>
19 </indexterm>
20
21 <indexterm zone="ch-system-createfiles">
22 <primary sortas="e-/var/run/utmp">/var/run/utmp</primary>
23 </indexterm>
24
25 <indexterm zone="ch-system-createfiles">
26 <primary sortas="e-/var/log/btmp">/var/log/btmp</primary>
27 </indexterm>
28
29 <indexterm zone="ch-system-createfiles">
30 <primary sortas="e-/var/log/lastlog">/var/log/lastlog</primary>
31 </indexterm>
32
33 <indexterm zone="ch-system-createfiles">
34 <primary sortas="e-/var/log/wtmp">/var/log/wtmp</primary>
35 </indexterm>
36
37 <para>Some programs use hard-wired paths to programs which do not exist yet. In
38 order to satisfy these programs, create a number of symbolic links which will be
39 replaced by real files throughout the course of this chapter after the software
40 has been installed:</para>
41
42<screen><userinput>ln -sv /tools/bin/{bash,cat,echo,pwd,stty} /bin
43ln -sv /tools/bin/perl /usr/bin
44ln -sv /tools/lib/libgcc_s.so{,.1} /usr/lib
45ln -sv /tools/lib/libstdc++.so{,.6} /usr/lib
46sed 's/tools/usr/' /tools/lib/libstdc++.la > /usr/lib/libstdc++.la
47ln -sv bash /bin/sh</userinput></screen>
48
49 <variablelist>
50 <title>The purpose of each link:</title>
51
52 <varlistentry>
53 <term><parameter><filename>/bin/bash</filename></parameter></term>
54 <listitem>
55 <para>Many <command>bash</command> scripts specify
56 <filename>/bin/bash</filename>.</para>
57 </listitem>
58 </varlistentry>
59
60 <varlistentry>
61 <term><parameter><filename>/bin/cat</filename></parameter></term>
62 <listitem>
63 <para>This pathname is hard-coded into Glibc's configure script.</para>
64 </listitem>
65 </varlistentry>
66
67 <varlistentry>
68 <term><parameter><filename>/bin/echo</filename></parameter></term>
69 <listitem>
70 <para>This is to satisfy one of the tests in Glibc's test suite, which
71 expects <filename>/bin/echo</filename>.</para>
72 </listitem>
73 </varlistentry>
74
75 <varlistentry>
76 <term><parameter><filename>/bin/pwd</filename></parameter></term>
77 <listitem>
78 <para>Some <command>configure</command> scripts, particularly Glibc's,
79 have this pathname hard-coded.</para>
80 </listitem>
81 </varlistentry>
82
83 <varlistentry>
84 <term><parameter><filename>/bin/stty</filename></parameter></term>
85 <listitem>
86 <para>This pathname is hard-coded into Expect, therefore it is needed
87 for Binutils and GCC test suites to pass.</para>
88 </listitem>
89 </varlistentry>
90
91 <varlistentry>
92 <term><parameter><filename>/usr/bin/perl</filename></parameter></term>
93 <listitem>
94 <para>Many Perl scripts hard-code this path to the
95 <command>perl</command> program.</para>
96 </listitem>
97 </varlistentry>
98
99 <varlistentry>
100 <term><parameter><filename>/usr/lib/libgcc_s.so{,.1}</filename></parameter></term>
101 <listitem>
102 <para>Glibc needs this for the pthreads library to work.</para>
103 </listitem>
104 </varlistentry>
105
106 <varlistentry>
107 <term><parameter><filename>/usr/lib/libstdc++{,.6}</filename></parameter></term>
108 <listitem>
109 <para>This is needed by several tests in Glibc's test suite, as well as
110 for C++ support in GMP.</para>
111 </listitem>
112 </varlistentry>
113
114 <varlistentry>
115 <term><parameter><filename>/usr/lib/libstdc++.la</filename></parameter></term>
116 <listitem>
117 <para>This prevents a <filename class="directory">/tools</filename>
118 reference that would otherwise be in
119 <filename>/usr/lib/libstdc++.la</filename> after GCC is installed.</para>
120 </listitem>
121 </varlistentry>
122
123 <varlistentry>
124 <term><parameter><filename>/bin/sh</filename></parameter></term>
125 <listitem>
126 <para>Many shell scripts hard-code <filename>/bin/sh</filename>.</para>
127 </listitem>
128 </varlistentry>
129
130 </variablelist>
131
132 <para>Historically, Linux maintains a list of the mounted file systems in the
133 file <filename>/etc/mtab</filename>. Modern kernels maintain this list
134 internally and exposes it to the user via the <filename
135 class="directory">/proc</filename> filesystem. To satisfy utilities that
136 expect the presence of <filename>/etc/mtab</filename>, create the following
137 symbolic link:</para>
138
139<screen><userinput>ln -sv /proc/self/mounts /etc/mtab</userinput></screen>
140
141 <para>In order for user <systemitem class="username">root</systemitem> to be
142 able to login and for the name <quote>root</quote> to be recognized, there
143 must be relevant entries in the <filename>/etc/passwd</filename> and
144 <filename>/etc/group</filename> files.</para>
145
146 <para>Create the <filename>/etc/passwd</filename> file by running the following
147 command:</para>
148
149<screen><userinput>cat &gt; /etc/passwd &lt;&lt; "EOF"
150<literal>root:x:0:0:root:/root:/bin/bash
151bin:x:1:1:bin:/dev/null:/bin/false
152daemon:x:6:6:Daemon User:/dev/null:/bin/false
153messagebus:x:18:18:D-Bus Message Daemon User:/var/run/dbus:/bin/false
154systemd-bus-proxy:x:72:72:systemd Bus Proxy:/:/bin/false
155systemd-journal-gateway:x:73:73:systemd Journal Gateway:/:/bin/false
156systemd-journal-remote:x:74:74:systemd Journal Remote:/:/bin/false
157systemd-journal-upload:x:75:75:systemd Journal Upload:/:/bin/false
158systemd-network:x:76:76:systemd Network Management:/:/bin/false
159systemd-resolve:x:77:77:systemd Resolver:/:/bin/false
160systemd-timesync:x:78:78:systemd Time Synchronization:/:/bin/false
161systemd-coredump:x:79:79:systemd Core Dumper:/:/bin/false
162nobody:x:99:99:Unprivileged User:/dev/null:/bin/false</literal>
163EOF</userinput></screen>
164
165 <para>The actual password for <systemitem class="username">root</systemitem>
166 (the <quote>x</quote> used here is just a placeholder) will be set later.</para>
167
168 <para>Create the <filename>/etc/group</filename> file by running the following
169 command:</para>
170
171<screen><userinput>cat &gt; /etc/group &lt;&lt; "EOF"
172<literal>root:x:0:
173bin:x:1:daemon
174sys:x:2:
175kmem:x:3:
176tape:x:4:
177tty:x:5:
178daemon:x:6:
179floppy:x:7:
180disk:x:8:
181lp:x:9:
182dialout:x:10:
183audio:x:11:
184video:x:12:
185utmp:x:13:
186usb:x:14:
187cdrom:x:15:
188adm:x:16:
189messagebus:x:18:
190systemd-journal:x:23:
191input:x:24:
192mail:x:34:
193systemd-bus-proxy:x:72:
194systemd-journal-gateway:x:73:
195systemd-journal-remote:x:74:
196systemd-journal-upload:x:75:
197systemd-network:x:76:
198systemd-resolve:x:77:
199systemd-timesync:x:78:
200systemd-coredump:x:79:
201nogroup:x:99:
202users:x:999:</literal>
203EOF</userinput></screen>
204
205 <para>The created groups are not part of any standard&mdash;they are groups
206 decided on in part by the requirements of the Udev configuration in this
207 chapter, and in part by common convention employed by a number of existing
208 Linux distributions. In addition, some test suites rely on specific users
209 or groups. The Linux Standard Base (LSB, available at <ulink
210 url="http://www.linuxbase.org"/>) recommends only that, besides the group
211 <systemitem class="groupname">root</systemitem> with a Group ID (GID) of 0,
212 a group <systemitem class="groupname">bin</systemitem> with a GID of 1 be
213 present. All other group names and GIDs can be chosen freely by the system
214 administrator since well-written programs do not depend on GID numbers, but
215 rather use the group's name.</para>
216
217 <para>To remove the <quote>I have no name!</quote> prompt, start a new
218 shell. Since a full Glibc was installed in <xref
219 linkend="chapter-temporary-tools"/> and the
220 <filename>/etc/passwd</filename> and <filename>/etc/group</filename>
221 files have been created, user name and group name resolution will now
222 work:</para>
223
224<screen role="nodump"><userinput>exec /tools/bin/bash --login +h</userinput></screen>
225
226 <para>Note the use of the <parameter>+h</parameter> directive. This tells
227 <command>bash</command> not to use its internal path hashing. Without this
228 directive, <command>bash</command> would remember the paths to binaries it has
229 executed. To ensure the use of the newly compiled binaries as soon as they are
230 installed, the <parameter>+h</parameter> directive will be used for the duration
231 of this chapter.</para>
232
233 <para>The <command>login</command>, <command>agetty</command>, and
234 <command>init</command> programs (and others) use a number of log
235 files to record information such as who was logged into the system and
236 when. However, these programs will not write to the log files if they
237 do not already exist. Initialize the log files and give them
238 proper permissions:</para>
239
240<screen><userinput>touch /var/log/{btmp,lastlog,wtmp}
241chgrp -v utmp /var/log/lastlog
242chmod -v 664 /var/log/lastlog
243chmod -v 600 /var/log/btmp</userinput></screen>
244
245 <para>The <filename>/var/log/wtmp</filename> file records all logins and
246 logouts. The <filename>/var/log/lastlog</filename> file records when each
247 user last logged in. The <filename>/var/log/btmp</filename> file records the
248 bad login attempts.</para>
249
250 <note><para>The <filename>/run/utmp</filename> file records the users that
251 are currently logged in. This file is created dynamically in the boot
252 scripts.</para></note>
253
254</sect1>
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