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-              r287ea55
+              r673b0d8
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
+  <!ENTITY % general-entities SYSTEM "../general.ent">
+  %general-entities;
+]>
 <chapter id="chapter-temporary-tools" xreflabel="Chapter 5">
+<?dbhtml dir="chapter05"?>
 <title>Constructing a temporary system</title>
 <?dbhtml filename="chapter05.html" dir="chapter05"?>
+<?dbhtml filename="chapter05.html"?>
+<sect1 id="ch-tools-introduction">
+<title>Introduction</title>
+<?dbhtml filename="introduction.html" dir="chapter05"?>
+<para>In this chapter we will compile and install a minimal
+Linux system. This system will contain just enough tools to be able
+to start constructing the final LFS system in the next chapter.</para>
+<para>The building of this minimal system is done in two steps: first we
+build a brand-new and host-independent toolchain (compiler, assembler,
+linker and libraries), and then use this to build all the other essential
+tools.</para>
+<para>The files compiled in this chapter will be installed under the
+<filename class="directory">$LFS/tools</filename> directory
+to keep them separate from the files installed in the next chapter.
+Since the packages compiled here are merely temporary, we don't want
+them to pollute the soon-to-be LFS system.</para>
+<para>Before issuing the build instructions for a package you are expected to
+have already unpacked it as user <emphasis>lfs</emphasis>, and to have
+performed a <userinput>cd</userinput> into the created directory. The build
+instructions assume that you are using the <command>bash</command>
+shell.</para>
+<para>Several of the packages are patched before compilation, but only when
+the patch is needed to circumvent a problem. Often the patch is needed in
+both this and the next chapter, but sometimes in only one of them. Therefore,
+don't worry when instructions for a downloaded patch seem to be missing. Also,
+when applying a patch, you'll occasionally see warning messages about
+<emphasis>offset</emphasis> or <emphasis>fuzz</emphasis>. These warnings are
+nothing to worry about, as the patch was still successfully applied.</para>
+<para>During the compilation of most packages you will see many warnings
+scroll by on your screen. These are normal and can safely be ignored. They are
+just what they say they are: warnings -- mostly about deprecated, but not
+invalid, use of the C or C++ syntax. It's just that C standards have changed
+rather often and some packages still use the older standard, which is not
+really a problem.</para>
+<para>After installing each package you should delete its source and build
+directories, <emphasis>unless</emphasis> told otherwise. Deleting the sources
+saves space, but also prevents misconfiguration when the same package is
+reinstalled further on. Only for three packages you will need to keep the
+source and build directories around for a while, so their contents can be used
+by later commands. Do not miss the reminders.</para>
+</sect1>
+<sect1 id="tools-technicalnotes">
+<title>Technical notes</title>
+<?dbhtml filename="technicalnotes.html" dir="chapter05"?>
+<para>This section attempts to explain some of the rationale and technical
+details behind the overall build method. It's not essential that you understand
+everything here immediately. Most of it will make sense once you have performed
+an actual build. Feel free to refer back here at any time.</para>
+<para>The overall goal of <xref linkend="chapter-temporary-tools"/> is to provide a sane,
+temporary environment that we can chroot into, and from which we can produce a
+clean, trouble-free build of the target LFS system in
+<xref linkend="chapter-building-system"/>. Along the way, we attempt to divorce ourselves
+from the host system as much as possible, and in so doing build a
+self-contained and self-hosted toolchain. It should be noted that the
+build process has been designed in such a way so as to minimize the risks for
+new readers and provide maximum educational value at the same time. In other
+words, more advanced techniques could be used to build the system.</para>
+<important>
+<para>Before continuing, you really should be aware of the name of your working
+platform, often also referred to as the <emphasis>target triplet</emphasis>. For
+many folks the target triplet will probably be
+<emphasis>i686-pc-linux-gnu</emphasis>. A simple way to determine your target
+triplet is to run the <filename>config.guess</filename> script that comes with
+the source for many packages. Unpack the Binutils sources and run the script:
+<userinput>./config.guess</userinput> and note the output.</para>
+<para>You'll also need to be aware of the name of your platform's
+<emphasis>dynamic linker</emphasis>, often also referred to as the
+<emphasis>dynamic loader</emphasis>, not to be confused with the standard linker
+<emphasis>ld</emphasis> that is part of Binutils. The dynamic linker is provided
+by Glibc and has the job of finding and loading the shared libraries needed by a
+program, preparing the program to run and then running it. For most folks the
+name of the dynamic linker will be <emphasis>ld-linux.so.2</emphasis>. On
+platforms that are less prevalent, the name might be
+<emphasis>ld.so.1</emphasis> and newer 64 bit platforms might even have
+something completely different. You should be able to determine the name
+of your platform's dynamic linker by looking in the
+<filename class="directory">/lib</filename> directory on your host system. A
+surefire way is to inspect a random binary from your host system by running:
+<userinput>readelf -l &lt;name of binary&gt; | grep interpreter</userinput>
+and noting the output. The authoritative reference covering all platforms is in
+the <filename>shlib-versions</filename> file in the root of the Glibc source
+tree.</para>
+</important>
+<para>Some key technical points of how the <xref linkend="chapter-temporary-tools"/> build
+method works:</para>
+<itemizedlist>
+<listitem><para>Similar in principle to cross compiling whereby tools installed
+into the same prefix work in cooperation and thus utilize a little GNU
+"magic".</para></listitem>
+<listitem><para>Careful manipulation of the standard linker's library search
+path to ensure programs are linked only against libraries we
+choose.</para></listitem>
+<listitem><para>Careful manipulation of <command>gcc</command>'s
+<emphasis>specs</emphasis> file to tell the compiler which target dynamic
+linker will be used.</para></listitem>
+</itemizedlist>
+<para>Binutils is installed first because both GCC and Glibc perform various
+feature tests on the assembler and linker during their respective runs of
+<command>./configure</command> to determine which software features to enable
+or disable. This is more important than one might first realize. An incorrectly
+configured GCC or Glibc can result in a subtly broken toolchain where the impact
+of such breakage might not show up until near the end of the build of a whole
+distribution. Thankfully, a test suite failure will usually alert us before too
+much time is wasted.</para>
+<para>Binutils installs its assembler and linker into two locations,
+<filename class="directory">/tools/bin</filename> and
+<filename class="directory">/tools/$TARGET_TRIPLET/bin</filename>. In reality,
+the tools in one location are hard linked to the other. An important facet of
+the linker is its library search order. Detailed information can be obtained
+from <command>ld</command> by passing it the <emphasis>--verbose</emphasis>
+flag. For example: <command>ld --verbose | grep SEARCH</command> will
+show you the current search paths and their order. You can see what files are
+actually linked by <command>ld</command> by compiling a dummy program and
+passing the <emphasis>--verbose</emphasis> switch to the linker. For example:
+<command>gcc dummy.c -Wl,--verbose 2>&amp;1 | grep succeeded</command>
+will show you all the files successfully opened during the linking.</para>
+<para>The next package installed is GCC and during its run of
+<command>./configure</command> you'll see, for example:</para>
+<blockquote><screen>checking what assembler to use... /tools/i686-pc-linux-gnu/bin/as
+checking what linker to use... /tools/i686-pc-linux-gnu/bin/ld</screen></blockquote>
+<para>This is important for the reasons mentioned above. It also demonstrates
+that GCC's configure script does not search the PATH directories to find which
+tools to use. However, during the actual operation of <command>gcc</command>
+itself, the same search paths are not necessarily used. You can find out which
+standard linker <command>gcc</command> will use by running:
+<command>gcc -print-prog-name=ld</command>.
+Detailed information can be obtained from <command>gcc</command> by passing
+it the <emphasis>-v</emphasis> flag while compiling a dummy program. For
+example: <command>gcc -v dummy.c</command> will show you detailed
+information about the preprocessor, compilation and assembly stages, including
+<command>gcc</command>'s include search paths and their order.</para>
+<para>The next package installed is Glibc. The most important considerations for
+building Glibc are the compiler, binary tools and kernel headers. The compiler
+is generally no problem as Glibc will always use the <command>gcc</command>
+found in a PATH directory. The binary tools and kernel headers can be a little
+more troublesome. Therefore we take no risks and use the available configure
+switches to enforce the correct selections. After the run of
+<command>./configure</command> you can check the contents of the
+<filename>config.make</filename> file in the
+<filename class="directory">glibc-build</filename> directory for all the
+important details. You'll note some interesting items like the use of
+<emphasis>CC="gcc -B/tools/bin/"</emphasis> to control which binary tools are
+used, and also the use of the <emphasis>-nostdinc</emphasis> and
+<emphasis>-isystem</emphasis> flags to control the compiler's include search
+path. These items help to highlight an important aspect of the Glibc package:
+it is very self-sufficient in terms of its build machinery and generally does
+not rely on toolchain defaults.</para>
+<para>After the Glibc installation, we make some adjustments to ensure that
+searching and linking take place only within our <filename>/tools</filename>
+prefix. We install an adjusted <command>ld</command>, which has a hard-wired
+search path limited to <filename class="directory">/tools/lib</filename>. Then
+we amend <command>gcc</command>'s specs file to point to our new dynamic
+linker in <filename class="directory">/tools/lib</filename>. This last step is
+<emphasis>vital</emphasis> to the whole process. As mentioned above, a
+hard-wired path to a dynamic linker is embedded into every ELF shared
+executable. You can inspect this by running:
+<command>readelf -l &lt;name of binary&gt; | grep interpreter</command>.
+By amending <command>gcc</command>'s specs file, we are ensuring that every
+program compiled from here through the end of this chapter will use our new
+dynamic linker in <filename class="directory">/tools/lib</filename>.</para>
+<para>The need to use the new dynamic linker is also the reason why we apply the
+Specs patch for the second pass of GCC. Failure to do so will result in the GCC
+programs themselves having the name of the dynamic linker from the host system's
+<filename class="directory">/lib</filename> directory embedded into them, which
+would defeat our goal of getting away from the host.</para>
+<para>During the second pass of Binutils, we are able to utilize the
+<emphasis>--with-lib-path</emphasis> configure switch to control
+<command>ld</command>'s library search path. From this point onwards, the
+core toolchain is self-contained and self-hosted. The remainder of the
+<xref linkend="chapter-temporary-tools"/> packages all build against the new Glibc in
+<filename class="directory">/tools</filename> and all is well.</para>
+<para>Upon entering the chroot environment in <xref linkend="chapter-building-system"/>, the
+first major package we install is Glibc, due to its self-sufficient nature that
+we mentioned above. Once this Glibc is installed into
+<filename class="directory">/usr</filename>, we perform a quick changeover of
+the toolchain defaults, then proceed for real in building the rest of the
+target LFS system.</para>
+</sect1>
+<sect1 id="tools-aboutlinking">
+<title>Notes on static linking</title>
+<?dbhtml filename="aboutlinking.html" dir="chapter05"?>
+<para>Most programs have to perform, beside their specific task, many rather
+common and sometimes trivial operations. These include allocating memory,
+searching directories, reading and writing files, string handling, pattern
+matching, arithmetic and many other tasks. Instead of obliging each program to
+reinvent the wheel, the GNU system provides all these basic functions in
+ready-made libraries. The major library on any Linux system is
+<emphasis>Glibc</emphasis>.</para>
+<para>There are two primary ways of linking the functions from a library to a
+program that uses them: statically or dynamically. When a program is linked
+statically, the code of the used functions is included in the executable,
+resulting in a rather bulky program. When a program is dynamically linked, what
+is included is a reference to the dynamic linker, the name of the library, and
+the name of the function, resulting in a much smaller executable. (A third way
+is to use the programming interface of the dynamic linker. See the
+<emphasis>dlopen</emphasis> man page for more information.)</para>
+<para>Dynamic linking is the default on Linux and has three major advantages
+over static linking. First, you need only one copy of the executable library
+code on your hard disk, instead of having many copies of the same code included
+into a whole bunch of programs -- thus saving disk space. Second, when several
+programs use the same library function at the same time, only one copy of the
+function's code is required in core -- thus saving memory space. Third, when a
+library function gets a bug fixed or is otherwise improved, you only need to
+recompile this one library, instead of having to recompile all the programs that
+make use of the improved function.</para>
+<para>If dynamic linking has several advantages, why then do we statically link
+the first two packages in this chapter? The reasons are threefold: historical,
+educational, and technical. Historical, because earlier versions of LFS
+statically linked every program in this chapter. Educational, because knowing
+the difference is useful. Technical, because we gain an element of independence
+from the host in doing so, meaning that those programs can be used
+independently of the host system. However, it's worth noting that an overall
+successful LFS build can still be achieved when the first two packages are
+built dynamically.</para>
+</sect1>
+&c5-binutils-pass1;
+&c5-gcc-pass1;
+&c5-kernelheaders;
+&c5-glibc;
+<sect1 id="ch-tools-adjusting">
+<title>Adjusting the toolchain</title>
+<?dbhtml filename="adjusting.html" dir="chapter05"?>
+<para>Now that the temporary C libraries have been installed, we want all
+the tools compiled in the rest of this chapter to be linked against these
+libraries. To accomplish this, we need to adjust the linker and the compiler's
+specs file. Some people would say that it is <emphasis>"black magic juju below
+this line"</emphasis>, but it is really very simple.</para>
+<para>First install the adjusted linker (adjusted at the end of the first pass
+of Binutils) by running the following command from within
+the <filename class="directory">binutils-build</filename> directory:</para>
+<screen><userinput>make -C ld install</userinput></screen>
+<para>From this point onwards everything will link <emphasis>only</emphasis>
+against the libraries in <filename>/tools/lib</filename>.</para>
+<note><para>If you somehow missed the earlier warning to retain the Binutils
+source and build directories from the first pass or otherwise accidentally
+deleted them or just don't have access to them, don't worry, all is not lost.
+Just ignore the above command. The result is a small chance of the subsequent
+testing programs linking against libraries on the host. This is not ideal, but
+it's not a major problem. The situation is corrected when we install the
+second pass of Binutils a bit further on.</para></note>
+<para>Now that the adjusted linker is installed, you have to
+<emphasis>remove</emphasis> the Binutils build and source directories.</para>
+<para>The next thing to do is to amend our GCC specs file so that it points
+to the new dynamic linker. A simple sed will accomplish this:</para>
+<!-- Ampersands are needed to allow cut and paste -->
+<screen><userinput>SPECFILE=/tools/lib/gcc-lib/*/*/specs &amp;&amp;
+sed -e 's@ /lib/ld-linux.so.2@ /tools/lib/ld-linux.so.2@g' \
+&nbsp;&nbsp;&nbsp;&nbsp;$SPECFILE &gt; tempspecfile &amp;&amp;
+mv -f tempspecfile $SPECFILE &amp;&amp;
+unset SPECFILE</userinput></screen>
+<para>We recommend that you cut-and-paste the above rather than try and type it
+all in. Or you can edit the specs file by hand if you want to: just replace the
+occurrence of "/lib/ld-linux.so.2" with "/tools/lib/ld-linux.so.2". Be sure to
+visually inspect the specs file to verify the intended change was actually
+made.</para>
+<important><para>If you are working on a platform where the name of the dynamic
+linker is something other than <filename>ld-linux.so.2</filename>, you
+<emphasis>must</emphasis> substitute <filename>ld-linux.so.2</filename> with the
+name of your platform's dynamic linker in the above commands. Refer back to
+<xref linkend="tools-technicalnotes"/> if necessary.</para></important>
+<para>Lastly, there is a possibility that some include files from the host
+system have found their way into GCC's private include dir. This can happen
+because of GCC's "fixincludes" process which runs as part of the GCC build.
+We'll explain more about this further on in this chapter. For now, run the
+following commands to eliminate this possibility:</para>
+<screen><userinput>rm -f /tools/lib/gcc-lib/*/*/include/{pthread.h,bits/sigthread.h}</userinput></screen>
+<!-- HACK - Force some whitespace to appease tidy -->
+<literallayout></literallayout>
+<caution><para>It is imperative at this point to stop and ensure that the basic
+functions (compiling and linking) of the new toolchain are working as expected.
+For this we are going to perform a simple sanity check:</para>
+<screen><userinput>echo 'main(){}' &gt; dummy.c
+cc dummy.c
+readelf -l a.out | grep ': /tools'</userinput></screen>
+<para>If everything is working correctly, there should be no errors, and the
+output of the last command will be (allowing for platform specific differences
+in dynamic linker name):</para>
+<blockquote><screen>[Requesting program interpreter: /tools/lib/ld-linux.so.2]</screen></blockquote>
+<para>Note especially that <filename class="directory">/tools/lib</filename>
+appears as the prefix of our dynamic linker.</para>
+<para>If you did not receive the output
+as shown above, or received no output at all, then something is seriously wrong.
+You will need to investigate and retrace your steps to find out where the
+problem is and correct it. There is no point in continuing until this is done.
+First, redo the sanity check using <command>gcc</command> instead of
+<command>cc</command>. If this works it means the
+<filename class="symlink">/tools/bin/cc</filename> symlink is missing. Revisit
+<xref linkend="ch-tools-gcc-pass1"/> and fix the symlink. Second, ensure your PATH
+is correct. You can check this by running <userinput>echo $PATH</userinput> and
+verifying that <filename class="directory">/tools/bin</filename> is at the head
+of the list. If the PATH is wrong it could mean you're not logged in as user
+<emphasis>lfs</emphasis> or something went wrong back in <xref
+linkend="prepare-settingenvironment"/>. Third, something may have gone wrong
+with the specs file amendment above. In this case redo the specs file amendment
+ensuring to cut-and-paste the commands as was recommended.</para>
+<para>Once you are satisfied that all is well, clean up the test files:</para>
+<screen><userinput>rm dummy.c a.out</userinput></screen>
+</caution>
+<!-- HACK - Force some whitespace to appease tidy -->
+<literallayout></literallayout>
+</sect1>
+&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-perl;
+<sect1 id="ch-tools-stripping">
+<title>Stripping</title>
+<?dbhtml filename="stripping.html" dir="chapter05"?>
+<para>The steps in this section are optional, but if your LFS partition is
+rather small, you will be glad to learn that you can remove some unnecessary
+things. The executables and libraries you have built so far contain about 130
+MB of unneeded debugging symbols. Remove those symbols with:</para>
+<screen><userinput>strip --strip-debug /tools/lib/*
+strip --strip-unneeded /tools/{,s}bin/*</userinput></screen>
+<para>The last 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
+<emphasis>--strip-unneeded</emphasis> on the libraries -- the static ones
+would be destroyed and you would have to build the three toolchain packages
+all over again.</para>
+<para>To save another 30 MB, you can remove all the documentation:</para>
+<screen><userinput>rm -rf /tools/{doc,info,man}</userinput></screen>
+<para>You will now need to have at least 850 MB of free space on your LFS
+file system to be able to build and install Glibc in the next phase. If you can
+build and install Glibc, you can build and install the rest too.</para>
+</sect1>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="introduction.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="toolchaintechnotes.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="binutils-pass1.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="gcc-pass1.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="kernel-headers.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="glibc.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="adjusting.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="tcl.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="expect.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="dejagnu.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="gcc-pass2.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="binutils-pass2.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="gawk.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="coreutils.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="bzip2.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="gzip.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="diffutils.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="findutils.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="make.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="grep.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="sed.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="gettext.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="ncurses.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="patch.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="tar.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="texinfo.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="bash.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="util-linux.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="perl.xml"/>
+<xi:include xmlns:xi="http://www.w3.org/2003/XInclude" href="stripping.xml"/>
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