%general-entities; ]> 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. First, backup the /tools linker, and replace it with the adjusted linker we made in chapter 5. We'll also create a link to its counterpart in /tools/$(uname -m)-pc-linux-gnu/bin: mv -v /tools/bin/{ld,ld-old} mv -v /tools/$(uname -m)-pc-linux-gnu/bin/{ld,ld-old} mv -v /tools/bin/{ld-new,ld} ln -sv /tools/bin/ld /tools/$(uname -m)-pc-linux-gnu/bin/ld the next command amends the GCC specs file to achieve three goals: first point GCC to the new dynamic linker. Simply deleting all instances of /tools should leave us with the correct path to the dynamic linker. Second, let GCC know where to find the Glibc start files. Third, add the /usr/include directory at the end of the default search path, so that header files added in chapter 6 are found. A sed command accomplishes this: gcc -dumpspecs | sed -e 's@/tools@@g' \ -e '/\*startfile_prefix_spec:/{n;s@.*@/usr/lib/ @}' \ -e '/\*cpp:/{n;s@$@ -idirafter /usr/include@}' > \ `dirname $(gcc --print-libgcc-file-name)`/specs It is a good idea to visually inspect the specs file to verify the intended change was actually made. 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: echo 'int main(){}' > dummy.c cc dummy.c -v -Wl,--verbose &> dummy.log readelf -l a.out | grep ': /lib' There should be no errors, and the output of the last command will be (allowing for platform-specific differences in the dynamic linker name): [Requesting program interpreter: /lib64/ld-linux-x86-64.so.2] Note that on 64-bit systems /lib is the location of our dynamic linker, but is accessed via a symbolic link in /lib64. On 32-bit systems the interpreter should be /lib/ld-linux.so.2. Now make sure that we're setup to use the correct start files: grep -o '/usr/lib.*/crt[1in].*succeeded' dummy.log The output of the last command should be: /usr/lib/../lib/crt1.o succeeded /usr/lib/../lib/crti.o succeeded /usr/lib/../lib/crtn.o succeeded Verify that the compiler is searching for the correct header files: grep -B4 '^ /usr/include' dummy.log This command should return the following output: #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 On a 32 bit system, x86_64 is replaced with i686. Next, verify that the new linker is being used with the correct search paths: grep 'SEARCH.*/usr/lib' dummy.log |sed 's|; |\n|g' References to paths that have components with '-linux-gnu' should be ignored, but otherwise the output of the last command should be: SEARCH_DIR("/usr/lib") SEARCH_DIR("/lib") Next make sure that we're using the correct libc: grep "/lib.*/libc.so.6 " dummy.log The output of the last command should be: attempt to open /usr/lib/libc.so.6 succeeded Make sure GCC is using the correct dynamic linker: grep found dummy.log The output of the last command should be (allowing for platform-specific differences in dynamic linker name): found ld-linux-x86-64.so.2 at /usr/lib/ld-linux-x86-64.so.2 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. Any issues will need to be resolved before continuing with the process. Once everything is working correctly, clean up the test files: rm -v dummy.c a.out dummy.log