James, Very nice! This is not an easy thing to do. As Mick said, we do something very similar, all inside Docker containers, to speed up armhf builds on the amd64-arch CI systems the project uses to run tests and builds.
Building packages is an additional challenge, and requires installing even more package dependencies alongside the build-arch tool chain to get `dpkg-buildpackage` even to *agree to try* building your packages! The basic trick we use to get around incomplete `MultiArch` support is to install conflicting packages in a multistrap root under `/sysroot`, and tell the compiler and linker to grab headers and libraries from there with the `gcc --sysroot=/sysroot` argument. After that, the real fun begins! Your `libboost-python-dev` hack is a good example of the many tricks we use to make this work, and the result is a big, stinky mess. Happily, Docker neatly contains all this ugliness in an image that's easy to reproduce and easy to run, both in the project's CI systems and in our developer environments. You can see what exactly goes into it in the below GitHub repository (PRs are very welcome if you can improve it). Hopefully these kinks in `MultiArch` will be worked out some day and this will all be much simpler. https://github.com/zultron/mk-cross-builder John ________________________________________ From: machinekit@googlegroups.com <machinekit@googlegroups.com> on behalf of schoone...@gmail.com <schoone...@gmail.com> Sent: Saturday, April 20, 2019 8:56 PM To: machinekit@googlegroups.com Subject: Re: [Machinekit] Successful cross-compiling with Debian Stretch Hi James, I went on a similar journey a few years ago, first using a chroot file system and qemu and then multiarch cross builds. You learn a lot on the way and the latter is certainly faster. We have been using John Morris's multiarch cross compiling docker containers for a while now. They use the same approach as you did. If you install docker-ce and checkout dovetailautomata/mk-cross-builder:armhf_9 from dockerhub, you can build your packages with `scripts/build_docker -t armhf_9 -c deb -j $(nproc)` from the root dir of the machinekit repo. That is how we produce all the machinekit packages now and it works well locally too. regards On 19/04/19 17:30, James Gao wrote: Hi everyone, Just wanted to report that I got Machinekit to successfully cross-compile through a Debian Stretch debootstrap. It seems that the latest multiarch support in stretch is good enough that (most) of the armhf libraries installed correctly. This doesn't require qemu, so it takes a fraction of the time to build. I was searching for more instructions on how to do a cross-compile build, and came across this thread: https://groups.google.com/forum/#!topic/machinekit/HWS807SS8ks<https://groups.google.com/forum/#%21topic/machinekit/HWS807SS8ks> which requested a PR -- let me know if that's still preferred. This is partially for my own benefit, but here's a short summary of the commands I used to get it to work: sudo debootstrap --components=main,contrib,non-free stretch {DEST_FOLDER} http://deb.debian.org/debian/ I configured schroot to launch the system: cat <<EOF > /etc/schroot/chroot.d/amd64-stretch [amd64-stretch] description=Debian Stretch (amd64) directory={DEST_FOLDER} root-users={USERNAME} users={USERNAME} type=directory EOF schroot -s amd64-stretch Once inside, I configured multiarch and installed some basic packages: sudo dpkg --add-architecture armhf sudo apt update sudo apt install gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf cython pkg-config autoconf git libczmq-dev:armhf git pull https://github.com/machinekit/machinekit.git cd machinekit/src/ ./autogen.sh PKG_CONFIG_PATH="/usr/lib/arm-linux-gnueabihf/pkgconfig/" ./configure --with-platform-beaglebone --host arm-linux-gnueabihf Now the great dependency hunt begins -- basically just run the configure line, and install the :armhf version of whatever library it complains about. I can put together a more comprehensive list if requested. The only library that requires special treatment is libboost-python-dev. If you try to install the :armhf version of that library, it tries to replace python with the armhf version, which will break the system. I went ahead and just directly extracted only the contents of /usr/lib/arm-linux-gnueabihf/ from http://ftp.us.debian.org/debian/pool/main/b/boost1.62/libboost-python1.62.0_1.62.0+dfsg-4_armhf.deb and http://ftp.us.debian.org/debian/pool/main/b/boost1.62/libboost-python1.62-dev_1.62.0+dfsg-4_armhf.deb I'm pretty sure I have a working armhf build -- I haven't had a chance to run it on target yet because I need to figure out how to package it (currently still in the RIP environment). -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to machinekit+unsubscr...@googlegroups.com<mailto:machinekit+unsubscr...@googlegroups.com>. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout. -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to machinekit+unsubscr...@googlegroups.com<mailto:machinekit+unsubscr...@googlegroups.com>. Visit this group at https://groups.google.com/group/machinekit. 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