lfs-book/chapter05/chapter05.xml

<chapter id="chapter05">
<title>Preparing the LFS system</title>
<?dbhtml filename="chapter05.html" dir="chapter05"?>

&c5-introduction;
&c5-whystatic;
&c5-creatingstage1dir;
&c5-addinguser;
&c5-settingenviron;
&c5-binutils-pass1;
&c5-gcc-pass1;
&c5-kernelheaders;
&c5-glibc;
&c5-lockingglibc;
&c5-tcl;
&c5-expect;
&c5-dejagnu;
&c5-gcc-pass2;
&c5-binutils-pass2;
&c5-gawk;
&c5-coreutils;
&c5-bzip2;
&c5-gzip;
&c5-diffutils;
&c5-findutils;
&c5-make;
&c5-grep;
&c5-sed;
&c5-gettext;
&c5-ncurses;
&c5-patch;
&c5-tar;
&c5-texinfo;
&c5-bash;
&c5-utillinux;
&c5-perl;


<sect1 id="ch05-adjustingtoolchain">
<title>Re-adjusting the toolchain</title>
<?dbhtml filename="adjustingtoolchain.html" dir="chapter05"?>

<para>Now that we have compiled all the necessary tools, it is time to
re-adjust our toolchain. We will set it up so that it will link any newly
compiled program against the new Glibc, which is the first thing to get
compiled in the next chapter. Basically, this is the reverse of what we did
in the "Locking in" stage in the beginning of this chapter.</para>

<para>The first thing to do is to adjust the linker scripts. For this we
retained the <filename>binutils-build</filename> directory from the second
pass over Binutils. Do the following:</para>

<para><screen><userinput>cd binutils-build
make -C ld INSTALL=/stage1/bin/install install-data-local</userinput></screen></para>

<para>This installs the adjusted linker scripts. The linker scripts now contain
no mention of <filename>/stage1/lib</filename>. From now on every compiled
program will link <emphasis>only</emphasis> against the libraries in
<filename>/usr/lib</filename> and <filename>/lib</filename>. The extra
<userinput>INSTALL=/stage1/bin/install</userinput> is needed because the
Makefile created during the second pass still contains the reference to
<filename>/usr/bin/install</filename>, which we obviously haven't installed
yet.</para>

<para>You can now remove the Binutils source and build directories.</para>

<para>The next thing to do is to amend our GCC specs file so that it points to
the new dynamic linker. Just like earlier on, we use a sed to accomplish
this:</para>

<para><screen><userinput>CURRENTSPECFILE=/stage1/lib/gcc-lib/*/*/specs
sed -e 's@/stage1/lib/ld.so.1@/lib/ld.so.1@g' \
&nbsp;&nbsp;&nbsp;&nbsp;-e 's@/stage1/lib/ld-linux.so.2@/lib/ld-linux.so.2@g' \
&nbsp;&nbsp;&nbsp;&nbsp;$CURRENTSPECFILE > newspecfile
mv newspecfile $CURRENTSPECFILE
unset CURRENTSPECFILE</userinput></screen></para>

<para>Again, cutting and pasting the above is recommended. And just like
before, it is a good idea to check the linker scripts and the specs file to
ensure the intended changes were actually made.</para>

<para>Note that the linker scripts will still contain a reference to
<filename>/stage1/i686-pc-linux-gnu/lib</filename>. This is unavoidable, but
luckily does not present a problem. There are no libraries in that location
as all the temporary stage1 libraries are located in
<filename>/stage1/lib</filename>.</para>

</sect1>



<sect1 id="ch05-stripping">
<title>Stripping</title>
<?dbhtml filename="stripping.html" dir="chapter05"?>

<para>If your LFS partition is rather small, you will be glad to learn that you
can throw away some unnecessary things. The executables and libraries you have
built so far contain about 130 MB of unneeded debugging symbols. Remove those
symbols like this:</para>

<para><screen><userinput>strip --strip-unneeded /stage1/{,s}bin/*
strip --strip-debug /stage1/lib/*</userinput></screen></para>

<para>The first of the above commands will skip some twenty files, reporting
that it doesn't recognize their file format. Most of them are scripts instead
of binaries.</para>

<para>Take care <emphasis>not</emphasis> to use
<userinput>--strip-unneeded</userinput> on the libraries -- they would be
destroyed and you would have to build Glibc all over again.</para>

<para>To save another couple of megabytes, you can throw away the documentation
and some of the bigger unneeded programs:</para>

<para><screen><userinput>rm -r /stage1/share/{doc,info,man}
rm /stage1/bin/{addr2line,gprof,nm,size,strings,strip}</userinput></screen></para>

<para>You will now need to have at least 700 MB of free space on your LFS
filesystem to be able to build and install Glibc in the next phase.</para>

</sect1>

</chapter>