path: root/chapter05/glibc.xml

<sect1 id="ch05-glibc">
<title>Installing Glibc-&glibc-version;</title>
<?dbhtml filename="glibc.html" dir="chapter05"?>

<screen>Estimated build time:           &glibc-time-tools;
Estimated required disk space:  &glibc-compsize-tools;</screen>

&aa-glibc-shortdesc;
&aa-glibc-dep;

<sect2><title>&nbsp;</title><para>&nbsp;</para></sect2>

<sect2>
<title>Glibc installation</title>

<para>Before starting to install Glibc, you must <userinput>cd</userinput>
into the <filename>glibc-&glibc-version;</filename> directory and unpack
Glibc-linuxthreads in that directory, not in the directory where you usually
unpack all the sources.</para>

<note><para>We are going to run the test suite for Glibc in this chapter.
However, it's worth pointing out that running the Glibc test suite here
is considered not as important as running it in
<xref linkend="chapter06"/>.</para></note>

<para>This package is known to behave badly when you have changed its
default optimization flags (including the -march and -mcpu options).
Therefore, if you have defined any environment variables that override
default optimizations, such as CFLAGS and CXXFLAGS, we recommend unsetting
them when building Glibc.</para>

<para>Basically, compiling Glibc in any other way than the book suggests
is putting the stability of your system at risk.</para>

<para>Though it is a harmless message, the install stage of Glibc will
complain about the absence of <filename>/tools/etc/ld.so.conf</filename>.
Fix this annoying little warning with:</para>

<screen><userinput>mkdir /tools/etc
touch /tools/etc/ld.so.conf</userinput></screen>

<para>Also, Glibc has a subtle problem when compiled with GCC &gcc-version;.
Apply the following patch to fix this:</para>

<screen><userinput>patch -Np1 -i ../&glibc-sscanf-patch;</userinput></screen>

<para>The Glibc documentation recommends building Glibc outside of the source
directory in a dedicated build directory:</para>

<screen><userinput>mkdir ../glibc-build
cd ../glibc-build</userinput></screen>

<para>Next, prepare Glibc to be compiled:</para>

<screen><userinput>../glibc-&glibc-version;/configure --prefix=/tools \
&nbsp;&nbsp;&nbsp;&nbsp;--disable-profile --enable-add-ons \
&nbsp;&nbsp;&nbsp;&nbsp;--with-headers=/tools/include \
&nbsp;&nbsp;&nbsp;&nbsp;--with-binutils=/tools/bin \
&nbsp;&nbsp;&nbsp;&nbsp;--without-gd</userinput></screen>

<para>The meaning of the configure options:</para>

<itemizedlist>
<listitem><para><userinput>--disable-profile</userinput>: This disables the
building of the libraries with profiling information. Omit this option if you
plan to do profiling.</para></listitem>

<listitem><para><userinput>--enable-add-ons</userinput>: This enables any
add-ons that were installed with Glibc, in our case Linuxthreads.</para></listitem>

<listitem><para><userinput>--with-binutils=/tools/bin</userinput> and
<userinput>--with-headers=/tools/include</userinput>: Strictly speaking
these switches are not required. But they ensure nothing can go wrong with
regard to what kernel headers and Binutils programs get used during the
Glibc build.</para></listitem>

<listitem><para><userinput> --without-gd</userinput>: This switch ensures
that we don't build the <userinput>memusagestat</userinput> program, which
strangely enough insists on linking against the host's libraries (libgd,
libpng, libz, and so forth).</para></listitem>
</itemizedlist>

<para>During this stage you might see the following warning:</para>

<blockquote><screen>configure: WARNING:
*** These auxiliary programs are missing or incompatible versions: msgfmt
*** some features will be disabled.
*** Check the INSTALL file for required versions.</screen></blockquote>

<para>The missing or incompatible <filename>msgfmt</filename> program is
generally harmless, but it's believed it can sometimes cause problems when
running the test suite.</para>

<para>Compile the package:</para>

<screen><userinput>make</userinput></screen>

<para>Run the test suite:</para>

<screen><userinput>make check</userinput></screen>

<para>The Glibc test suite is highly dependent on certain functions of your host
system, in particular the kernel. Additionally, here in this chapter some tests
can be adversely affected by existing tools or environmental issues on the host
system. Of course, these won't be a problem when we run the Glibc test suite
inside the chroot environment of <xref linkend="chapter06"/>. In general, the
Glibc test suite is always expected to pass. However, as mentioned above, some
failures are unavoidable in certain circumstances. Here is a list of the most
common issues we are aware of:</para>

<itemizedlist>
<listitem><para>The <emphasis>math</emphasis> tests sometimes fail when running
on systems where the CPU is not a relatively new genuine Intel or authentic AMD.
Certain optimization settings are also known to be a factor here.</para></listitem>

<listitem><para>The <emphasis>gettext</emphasis> test sometimes fails due to
host system issues. The exact reasons are not yet clear.</para></listitem>

<listitem><para>The <emphasis>atime</emphasis> test sometimes fails when the
LFS partition is mounted with the <emphasis>noatime</emphasis> option, or due
to other file system quirks.</para></listitem>

<listitem><para>The <emphasis>shm</emphasis> test might fail when the host
system is running the devfs file system but doesn't have the tmpfs file system
mounted at <filename>/dev/shm</filename> due to lack of support for tmpfs in
the kernel.</para></listitem>

<listitem><para>When running on older and slower hardware, some tests might
fail due to test timeouts being exceeded.</para></listitem>
</itemizedlist>

<para>In summary, don't worry too much if you see Glibc test suite failures
here in this chapter. The Glibc in <xref linkend="chapter06"/> is the one we'll
ultimately end up using so that is the one we would really like to see pass.
But please keep in mind, even in <xref linkend="chapter06"/> some failures
could still occur -- the <emphasis>math</emphasis>
tests for example. When experiencing a failure, make a note of it, then
continue by reissuing the <userinput>make check</userinput>. The test suite
should pick up where it left off and continue on. You can circumvent this
stop-start sequence by issuing a <userinput>make -k check</userinput>. But if
you do that, be sure to log the output so that you can later peruse the log
file and examine the total number of failures.</para>

<para>Now install the package:</para>

<screen><userinput>make install</userinput></screen>

<para>Different countries and cultures have varying conventions for how to
communicate. These conventions range from very simple ones, such as the format
for representing dates and times, to very complex ones, such as the language
spoken. The "internationalization" of GNU programs works by means of
<emphasis>locales</emphasis>. We'll install the Glibc locales now:</para>

<screen><userinput>make localedata/install-locales</userinput></screen>

<para>An alternative to running the previous command is to install only
those locales which you need or want. This can be achieved by using the
<userinput>localedef</userinput> command. Information on this can be
found in the <filename>INSTALL</filename> file in the
<filename>glibc-&glibc-version;</filename> source. However, there are a number
of locales that are essential for the tests of future packages to pass, in
particular, the <emphasis>libstdc++</emphasis> tests from GCC.  The following
instructions, instead of the install-locales target above, will install
the minimum set of locales necessary for the tests to run successfully:</para>

<screen><userinput>mkdir -p /tools/lib/locale
localedef -i de_DE -f ISO-8859-1 de_DE
localedef -i de_DE@euro -f ISO-8859-15 de_DE@euro
localedef -i en_HK -f ISO-8859-1 en_HK
localedef -i en_PH -f ISO-8859-1 en_PH
localedef -i en_US -f ISO-8859-1 en_US
localedef -i es_MX -f ISO-8859-1 es_MX
localedef -i fr_FR -f ISO-8859-1 fr_FR
localedef -i fr_FR@euro -f ISO-8859-15 fr_FR@euro
localedef -i it_IT -f ISO-8859-1 it_IT
localedef -i ja_JP -f EUC-JP ja_JP</userinput></screen>

</sect2>

</sect1>