doc/src/crosscompile.html

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   6      Written by Ken Bantoft <ken@freeswan.ca> for the Linux FreeS/WAN project
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  23 <H1><A NAME="guide"></A>Linux FreeS/WAN Cross Compiling Guide</H1>
  24
  25 <H2><A NAME="overview"></A>Overview</H2>
  26
  27 <P>
  28 This document provides general instructions on how to cross compile
  29 FreeS/WAN,
  30 that is - compile it for another architecture (eg: StrongARM)</P>
  31 <OL>
  32         <LI><A HREF="#setup">Setting up your environment</A>.</LI>
  33         <LI><A HREF="#building">Building</A>.</LI>
  34         <LI><A HREF="#common">Common Problems</A>.</LI>
  35 </OL>
  36 <H2><A NAME="setup"></A>Setting up your Environment</H2>
  37 <H3>Enviroment Variables</H3>
  38 <P>There are a number of environment variables you can set to help facilitate
  39 cross compiling FreeS/WAN.  All examples will are using the bash shell.
  40 </P>
  41 <P>The following is an example of the how to set the environment variables if
  42 you were cross compiling using the Embedix ARM toolchain, to build for an embedded
  43 device like the Sharp Zaurus.  Set these while you are in the FreeS/WAN directory.
  44 It is often simpler to put the entire list into a script (eg: cross-setup.sh), and
  45 then "source cross-setup.sh" or similar.
  46 <pre>
  47 export ARCH=arm
  48 export CC=/opt/Embedix/tools/bin/arm-linux-gcc
  49 export LD=/opt/Embedix/tools/bin/arm-linux-ld
  50 export RANLIB=/opt/Embedix/tools/bin/arm-linux-ranlib
  51 export AR=/opt/Embedix/tools/bin/arm-linux-ar
  52 export AS=/opt/Embedix/tools/bin/arm-linux-as
  53 export STRIP=/opt/Embedix/tools/bin/arm-linux-strip
  54 export KERNELSRC=/zaurus/kernel-2.4.6
  55 export LD_LIBRARY_PATH=/opt/Embedix/tools/lib/gcc-lib/arm-linux/2.95.2/
  56 export PATH=$PATH:/opt/Embedix/tools/bin
  57 export DESTDIR=/zaurus/binaries
  58 </pre>
  59 In the example above, we setup all of the usual gcc + bin-utils programs,
  60 as well as setting the LD_LIBRARY_PATH to our cross-compiled system libraries,
  61 and DESTDIR to our output directory.
  62 </P>
  63
  64 <H3>Kernel Source</H3>
  65 <P>Place a copy of the kernel source, setup for your target device somewhere on
  66 your filesystem and set KERNELSRC= to this directory.  You will need to prepare
  67 your kernel source treefirst, by running "make menuconfig && make dep && make
  68 modules".  Once this is done, you can move on to building FreeS/WAN</P>
  69
  70 <H2><A NAME="building"></A>Building</H2>
  71 <H3>The Make Process</H3>
  72 <P>There are two parts to building FreeS/WAN - the userland programs and utilities,
  73 and the ipsec.o kernel module.  Each can be built seperatly, making debugging the
  74 build process simpler.
  75 </P>
  76 <P>Step 1 is to run "make programs".  This will build the required libs
  77 (libfreeswan.a) as well as all of the userland tools (pluto, whack, etc...).
  78 Provided your environment variables are set correctly, you should see the output
  79 using your specified gcc (arm-linux-gcc for our example), ld, as, ar and
  80 ranlib.</P>
  81 <P>If this completes successfully, you can run "make install" to install a copy of
  82 all of the binaries, man pages and other documentation to DESTDIR.</P>
  83 <P>Step 2 is to build the ipsec.o module.  This is done with "make oldmod", which
  84 should change into the KERNELSRC directory and then compile and link the required
  85 files to generate an ipsec.o file.  If this is successful, you will end up with an
  86 ipsec.o file in your FreeS/WAN directory, under linux/net/ipsec/.</P>
  87 <P>Remember to install this to /lib/modules/$kernelversion/kernel/net/ipsec/ on
  88 your target machine.</P>
  89
  90
  91
  92 <H2><A NAME="common"></A>Common Problems Building</H2>
  93 <P>Here is a list of common problems/errors you may run into when cross compiling
  94 FreeS/WAN.</P>
  95 <UL>
  96 <LI>gmp.h, libgmp not found, error with -lgmp.  All of these refer to the GNU Math
  97 Precision Library.  You will need to have already built this for your target
  98 system.  Place libgmp.so in LD_LIBRARY_PATH, and ensure the headers are in your
  99 include path as well.
 100 </UL>
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