Bullseye armhf cross compile docker

From Technologic Systems Manuals

Debian only provides their cross compiler for their distribution. Our examples will set up a Docker for Debian to use for development. If using Debian 11 Bullseye directly, or through a VM then the docker usage can be skipped.

Create a file called "Dockerfile" with these contents:

FROM debian:bullseye

RUN dpkg --add-architecture armhf

RUN apt-get update && apt-get install -y \
    autogen \
    automake \
    bash \
    bc \
    bison \
    build-essential \
    bzip2 \
    ca-certificates \
    ccache \
    chrpath \
    cpio \
    curl \
    diffstat \
    fakeroot \
    file \
    flex \
    gawk \
    gcc-arm-linux-gnueabihf \
    git \
    gzip \
    kmod \
    libgpiod-dev:armhf \
    libncursesw5-dev \
    libssl-dev \
    libtool \
    locales \
    lzop \
    make \
    multistrap \
    ncurses-dev \
    pkg-config \
    python \
    python3 \
    python3-pip \
    python3-pexpect \
    qemu-user-static \
    rsync \
    socat \
    runit \
    texinfo \
    u-boot-tools \
    unzip \
    vim \
    wget \
    xz-utils

# To make a more readable PS1 to show we are in the Docker
ENV debian_chroot debian_bullseye
RUN echo "PS1='\${debian_chroot}\\[\033[01;32m\\]@\\H\[\\033[00m\\]:\\[\\033[01;34m\\]\\w\\[\\033[00m\\]\\$ '" >> /etc/bash.bashrc

# Set up locales.  Needed by yocto.
RUN sed -i -e 's/# en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/' /etc/locale.gen && \
        echo 'LANG="en_US.UTF-8"'>/etc/default/locale && \
        dpkg-reconfigure --frontend=noninteractive locales && \
        update-locale LANG=en_US.UTF-8

ENV LC_ALL en_US.UTF-8
ENV LANG en_US.UTF-8
ENV LANGUAGE en_US.UTF-8

In the same directory as the file named "Dockerfile" run:

docker build --tag armhf-bullseye-toolchain .

When this has finished the docker can be used with:

docker run --rm -it --volume $(pwd):/work armhf-bullseye-toolchain bash

This will map the current directory to /work.

At this point the Debian Docker is ready to compile armhf binaries. For example, create a hello world in your home folder at ~/hello.c

#include <stdio.h>
int main(){
    printf("Hello World\n");
}

To compile this enter the docker with:

docker run -it --volume $(pwd):/work armhf-bullseye-toolchain bash
# Then from the docker:
cd /work/
arm-linux-gnueabihf-gcc hello.c -o hello

Check "file hello" to verify the binary type:

debian_bullseye@b720b8ba6c1e:/work# file hello
hello: ELF 32-bit LSB pie executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-armhf.so.3, BuildID[sha1]=fc6389ca8da310bb5d0b87e5998b59894c078d9f, for GNU/Linux 3.2.0, not stripped

This can also be used to develop against dynamic libraries from Debian. The armhf packages can be installed in the Docker. For example, to link against curl:

# Enter the Docker:
docker run -it --volume $(pwd):/work armhf-bullseye-toolchain bash
cd /work/

apt-get install libcurl4-openssl-dev:armhf
# Download curl's simple.c example
wget https://raw.githubusercontent.com/bagder/curl/master/docs/examples/simple.c
arm-linux-gnueabihf-gcc simple.c -o simple -lcurl

The "simple" binary is now built for armhf and links dynamically to curl.

This will only retain the armhf libcurl package until the docker is exited. To make the changes permanent, add the package to the Dockerfile and rerun:

docker build --tag armhf-bullseye-toolchain .