1 | <sect1 id="ch05-settingenviron">
|
---|
2 | <title>Setting up the environment</title>
|
---|
3 | <?dbhtml filename="settingenvironment.html" dir="chapter05"?>
|
---|
4 |
|
---|
5 | <para>While logged in as user <emphasis>lfs</emphasis>, issue the
|
---|
6 | following commands to set up a good work environment:</para>
|
---|
7 |
|
---|
8 | <para><screen><userinput>cat > ~/.bash_profile << "EOF"</userinput>
|
---|
9 | set +h
|
---|
10 | umask 022
|
---|
11 | LFS=/mnt/lfs
|
---|
12 | LC_ALL=POSIX
|
---|
13 | PATH=/tools/bin:$PATH
|
---|
14 | export LFS LC_ALL PATH
|
---|
15 | unset CC CXX CPP LD_LIBRARY_PATH LD_PRELOAD
|
---|
16 | <userinput>EOF
|
---|
17 |
|
---|
18 | source ~/.bash_profile</userinput></screen></para>
|
---|
19 |
|
---|
20 | <para>The <userinput>set +h</userinput> command turns off
|
---|
21 | <userinput>bash</userinput>'s hash function. Normally hashing is a useful
|
---|
22 | feature: <userinput>bash</userinput> uses a hash table to remember the
|
---|
23 | full pathnames of executable files to avoid searching the PATH time and time
|
---|
24 | again to find the same executable. However, we'd like the new tools to be
|
---|
25 | used as soon as they are installed. By switching off the hash function, our
|
---|
26 | "interactive" commands (<userinput>make</userinput>,
|
---|
27 | <userinput>patch</userinput>, <userinput>sed</userinput>,
|
---|
28 | <userinput>cp</userinput> and so forth) will always use
|
---|
29 | the newest available version during the build process.</para>
|
---|
30 |
|
---|
31 | <para>Setting the user file-creation mask to 022 ensures that newly created
|
---|
32 | files and directories are only writable for their owner, but readable and
|
---|
33 | executable for anyone.</para>
|
---|
34 |
|
---|
35 | <para>The LFS variable should of course be set to the mount point you
|
---|
36 | chose.</para>
|
---|
37 |
|
---|
38 | <para>The LC_ALL variable controls the localization of certain programs,
|
---|
39 | making their messages follow the conventions of a specified country. If your
|
---|
40 | host system uses a version of <emphasis>glibc</emphasis> older than 2.2.4,
|
---|
41 | having LC_ALL set to something other than "POSIX" or "C" during this chapter
|
---|
42 | may cause trouble if you exit the chroot environment and wish to return later.
|
---|
43 | By setting LC_ALL to "POSIX" (or "C", the two are equivalent) we ensure that
|
---|
44 | everything will work as expected in the chroot environment.</para>
|
---|
45 |
|
---|
46 | <para>We prepend <filename>/tools/bin</filename> to the standard PATH so
|
---|
47 | that, as we move along through this chapter, the tools we build will get used
|
---|
48 | during the rest of the building process.</para>
|
---|
49 |
|
---|
50 | <para>The CC, CXX, CPP, LD_LIBRARY_PATH and LD_PRELOAD environment variables all
|
---|
51 | have the potential to cause havoc with our Chapter 5 toolchain. We therefore
|
---|
52 | unset them to prevent any chance of this happening.</para>
|
---|
53 |
|
---|
54 | <para>Now, after sourcing the just-created profile, we're all set to begin
|
---|
55 | building the temporary tools that will support us in later chapters.</para>
|
---|
56 |
|
---|
57 | </sect1>
|
---|
58 |
|
---|