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diff --git a/chapter06/adjusting.xml b/chapter06/adjusting.xml deleted file mode 100644 index 3e6b49e19..000000000 --- a/chapter06/adjusting.xml +++ /dev/null @@ -1,126 +0,0 @@ -<?xml version="1.0" encoding="ISO-8859-1"?> -<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" - "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ - <!ENTITY % general-entities SYSTEM "../general.ent"> - %general-entities; -]> - -<sect1 id="ch-system-adjusting"> - <?dbhtml filename="adjusting.html"?> - - <title>Adjusting the Toolchain</title> - - <para>Now that the final C libraries have been installed, it is time to adjust - the toolchain so that it will link any - newly compiled program against these new libraries.</para> - - <para>First, backup the <filename class="directory">/tools</filename> linker, - and replace it with the adjusted linker we made in chapter 5. We'll also create - a link to its counterpart in - <filename class="directory">/tools/$(uname -m)-pc-linux-gnu/bin</filename>:</para> - -<screen><userinput>mv -v /tools/bin/{ld,ld-old} -mv -v /tools/$(uname -m)-pc-linux-gnu/bin/{ld,ld-old} -mv -v /tools/bin/{ld-new,ld} -ln -sv /tools/bin/ld /tools/$(uname -m)-pc-linux-gnu/bin/ld</userinput></screen> - - <para>the next command amends the GCC specs file to achieve three goals: - first point GCC to the new dynamic linker. Simply deleting all instances of - <quote>/tools</quote> should leave us with the correct path to the dynamic - linker. Second, let GCC know where to find the Glibc start files. Third, - add the /usr/include directory at the end of the default search path, so - that header files added in chapter 6 are found. - A <command>sed</command> command accomplishes this:</para> - -<screen><userinput>gcc -dumpspecs | sed -e 's@/tools@@g' \ - -e '/\*startfile_prefix_spec:/{n;s@.*@/usr/lib/ @}' \ - -e '/\*cpp:/{n;s@$@ -idirafter /usr/include@}' > \ - `dirname $(gcc --print-libgcc-file-name)`/specs</userinput></screen> - - <para>It is a good idea to visually inspect the specs file to verify the - intended change was actually made.</para> - - <para>It is imperative at this point to ensure that the basic - functions (compiling and linking) of the adjusted toolchain are working - as expected. To do this, perform the following sanity checks:</para> - -<screen os="a"><userinput>echo 'int main(){}' > dummy.c -cc dummy.c -v -Wl,--verbose &> dummy.log -readelf -l a.out | grep ': /lib'</userinput></screen> - - <para os="b">There should be no errors, - and the output of the last command will be (allowing for - platform-specific differences in dynamic linker name):</para> - -<screen os="c"><computeroutput>[Requesting program interpreter: /lib64/ld-linux-x86-64.so.2]</computeroutput></screen> - - <para>Note that on 64-bit systems <filename class="directory">/lib</filename> is - the location of our dynamic linker, but is accessed via a symbolic link - in /lib64.</para> - - <note><para>On 32-bit systems the interpreter should be - /lib/ld-linux.so.2.</para></note> - - <para os="d">Now make sure that we're setup to use the correct start files:</para> - -<screen os="e"><userinput>grep -o '/usr/lib.*/crt[1in].*succeeded' dummy.log</userinput></screen> - - <para os="f">The output of the last command should be:</para> - -<screen><computeroutput>/usr/lib/../lib/crt1.o succeeded -/usr/lib/../lib/crti.o succeeded -/usr/lib/../lib/crtn.o succeeded</computeroutput></screen> - - <para os="g">Verify that the compiler is searching for the correct header - files:</para> - -<screen><userinput>grep -B4 '^ /usr/include' dummy.log</userinput></screen> - - <para os="h">This command should return the following output:</para> - -<screen><computeroutput>#include <...> search starts here: - /tools/lib/gcc/x86_64-pc-linux-gnu/&gcc-version;/include - /tools/include - /tools/lib/gcc/x86_64-pc-linux-gnu/&gcc-version;/include-fixed - /usr/include</computeroutput></screen> - - <note><para>On a 32 bit system, x86_64 is replaced with i686.</para></note> - - <para os="i">Next, verify that the new linker is being used with the correct search paths:</para> - -<screen os="j"><userinput>grep 'SEARCH.*/usr/lib' dummy.log |sed 's|; |\n|g'</userinput></screen> - - <para os="k">References to paths that have components with '-linux-gnu' should - be ignored, but otherwise the output of the last command should be:</para> - -<screen><computeroutput>SEARCH_DIR("/usr/lib") -SEARCH_DIR("/lib")</computeroutput></screen> - - <para os="l">Next make sure that we're using the correct libc:</para> - -<screen os="m"><userinput>grep "/lib.*/libc.so.6 " dummy.log</userinput></screen> - - <para os="n">The output of the last command should be:</para> - -<screen os="o"><computeroutput>attempt to open /lib/libc.so.6 succeeded</computeroutput></screen> - - <para os="p">Lastly, make sure GCC is using the correct dynamic linker:</para> - -<screen os="q"><userinput>grep found dummy.log</userinput></screen> - - <para os="r">The output of the last command should be (allowing for - platform-specific differences in dynamic linker name):</para> - -<screen os="s"><computeroutput>found ld-linux-x86-64.so.2 at /lib/ld-linux-x86-64.so.2</computeroutput></screen> - - <para os="t">If the output does not appear as shown above or is not received - at all, then something is seriously wrong. Investigate and retrace the - steps to find out where the problem is and correct it. The most likely - reason is that something went wrong with the specs file adjustment. Any - issues will need to be resolved before continuing with the process.</para> - - <para os="u">Once everything is working correctly, clean up the test files:</para> - -<screen os="v"><userinput>rm -v dummy.c a.out dummy.log</userinput></screen> - -</sect1> |