WIP

.gitignore

@@ -1,5 +1,5 @@
 
-/build
+/build*
 
 # ---> C++
 # Prerequisites

conanfile.py

@@ -10,7 +10,7 @@ class BmrConan(ConanFile):
 
     def configure(self):
         self.options["boost"].without_cobalt = True
-        if self.settings.arch == "armv7":
+        if self.settings.arch == "armv7" or self.settings.arch == "armv6":
             self.options["libpng"].neon = False
 
 

scripts/create-cross-compiler/README.md

@@ -0,0 +1,47 @@
+# Creating cross-compilers
+This folder contains configuration, scripts and docker images used in the creation of cross-compilers and a cross-compilation environment. The intended use case is that these scripts can be used to very easilly create an environment where we can build software for different platforms. Docker is being used to create a contained reproducable environment.
+
+For these scripts and instructions to work you only need docker and the bare minimum of shell scripting support.
+
+## How to use:
+1. Have this repository available on your local machine
+2. Build the cross compiler & create a cross build environment.
+   ``cd scripts/create-cross-compiler``
+   ``./create-armv6-rpi-linux-gnueabihf.sh``
+   The resulting cross compiler is stored in the "build-tools" folder. There will also be a docker image created that can be used in the process of building.
+3. Do some cross compiling
+````
+docker run -ti \
+    -v ../../:/workspace \
+    bmr-cross-compiler
+````
+
+How to build the software:
+````
+cd /workspace
+conan remote remove conancenter
+conan remote add conan-upload https://artifacts.4beumer.nl/repository/conan-bmrdev/
+conan remote add conan-remote https://artifacts.4beumer.nl/repository/conan-center-proxy/
+
+conan build . -of build-cross \
+   -s compiler.cppstd=23 \
+   -s build_type=Debug \
+   --build=missing \
+   -pr:b=/x-tools/armv6-rpi-linux-gnueabihf/conan.profile \
+   -pr:h=default
+
+cmake --preset conan-debug .
+cmake --preset conan-debug . 
+cmake --build ./build-cross
+````
+
+
+
+   * Configuration needs to be provided. (environment variable: CROSS_TARGET_INFO_PATH).
+   * Destination location needs to be provided (environment variable: CROSS_TARGET_DST_PATH).
+   * Use docker volume functionality to link directories to the docker container.
+   ``docker run -ti -e CROSS_TARGET_INFO_PATH=/config -e CROSS_TARGET_DST_PATH=/dst -v ./armv6-rpi-linux:/config -v ./dst:/dst <docker image name>``
+
+
+
+

scripts/create-cross-compiler/build-cross-compiler.Dockerfile

@@ -0,0 +1,89 @@
+FROM alpine:3.22.2
+
+# Install packages needed in both building and running.
+RUN apk update && \
+    apk add --no-cache \
+    libstdc++
+
+# Install tools required for building.
+RUN mkdir -p /root/.local/bin
+ENV PATH="${PATH}:/root/.local/bin"
+
+RUN apk add --no-cache \
+    autoconf \
+    bash \
+    binutils \
+    build-base \
+    cmake \
+    clang \
+    clang-extra-tools \
+    gdb \
+    git \
+    libtool \
+    linux-headers \
+    ninja \
+    m4 \
+    perl \
+    python3 \
+    pipx
+
+# Install tools we need for building the cross compiler.
+RUN apk add --no-cache \
+    gpg \
+    gpg-agent \
+    automake \
+    flex \
+    make \
+    texinfo \
+    xz \
+    help2man \
+    gawk \
+    bison \
+    ncurses-dev \
+    rsync \
+    wget
+
+RUN mkdir -p /workspace
+WORKDIR /workspace
+
+# Download crosstool-ng that we use to build the cross compiler.
+RUN <<EOF
+    gpg --keyserver pgp.surfnet.nl --recv-keys 721B0FB1CDC8318AEBB888B809F6DD5F1F30EF2E
+    wget http://crosstool-ng.org/download/crosstool-ng/crosstool-ng-1.28.0.tar.bz2.sig
+    wget http://crosstool-ng.org/download/crosstool-ng/crosstool-ng-1.28.0.tar.bz2
+    gpg --verify crosstool-ng-1.28.0.tar.bz2.sig
+    tar -xjf crosstool-ng-1.28.0.tar.bz2
+    mv /workspace/crosstool-ng-1.28.0 /crosstool
+EOF
+
+# - Add a user that we need for building (crosstool-ng requires non-root user for that).
+# - Add some directories we need in the future for building.
+# - Build crosstool-ng, which in it's turn will be used to build the cross compiler.
+
+ENV CROSS_DESTDIR=/x-tools
+
+WORKDIR /crosstool
+RUN <<EOF
+    adduser -D crosstoolng    
+
+    mkdir -p /home/crosstoolng/src
+    mkdir -p $CROSS_DESTDIR
+
+    ./bootstrap
+    ./configure
+    make DESTDIR=$CROSS_DESTDIR
+    make install
+
+    chown -R crosstoolng:crosstoolng /crosstool
+    chown -R crosstoolng:crosstoolng $CROSS_DESTDIR
+    chown -R crosstoolng:crosstoolng /home/crosstoolng
+EOF
+
+# We now have crosstool-ng built and ready to be used for building the cross-compiler that we actually want. To
+# do that we need to feed some configuration
+
+WORKDIR /workspace
+ADD --chmod=544 ./scripts/create-cross-compiler.py . 
+ADD --chmod=544 ./scripts/entrypoint.sh . 
+
+ENTRYPOINT ["./entrypoint.sh"]

scripts/create-cross-compiler/configurations/armv6-rpi-linux-gnueabihf/conan.profile

@@ -0,0 +1,12 @@
+[settings]
+os=Linux
+arch=armv6
+compiler=gcc
+build_type=Release
+compiler.cppstd=gnu17
+compiler.libcxx=libstdc++11
+compiler.version=14
+[buildenv]
+CC=/x-tools/armv6-rpi-linux-gnueabihf/bin/armv6-rpi-linux-gnueabihf-gcc
+CXX=/x-tools/armv6-rpi-linux-gnueabihf/bin/armv6-rpi-linux-gnueabihf-g++
+LD=/x-tools/armv6-rpi-linux-gnueabihf/bin/armv6-rpi-linux-gnueabihf-ld

scripts/create-cross-compiler/create-armv6-rpi-linux-gnueabihf.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+# Prepare a directory that will contain the cross compiler
+mkdir -p ../../build-tools/x-tools
+
+# Build docker image responsible for building the cross compiler
+docker build \
+    -t bmr-build-cross-compiler \
+    -f build-cross-compiler.Dockerfile .
+
+# Perform building of cross compiler
+docker run -ti \
+    -e CROSS_TARGET_INFO_PATH=/extern-config \
+    -e CROSS_TARGET_DST_PATH=/extern-dst \
+    -v ./configurations/armv6-rpi-linux-gnueabihf:/extern-config \
+    -v ../../build-tools/x-tools:/extern-dst \
+    bmr-build-cross-compiler
+    
+
+# Build docker image to be used for cross compiling
+docker build \
+    -t bmr-cross-compiler \
+    --build-arg CROSS_COMPILER=armv6-rpi-linux-gnueabihf \
+    -f cross-compiler.Dockerfile ../..
+

scripts/create-cross-compiler/scripts/create-cross-compiler.py

@@ -0,0 +1,57 @@
+#! /usr/bin/python
+import argparse
+import json
+import os
+import shutil
+import subprocess
+import sys
+
+def runcmd(command):
+    print('RUN ' + command)
+    process = subprocess.Popen(command, stdout=subprocess.PIPE, shell=True)
+    for line in iter(process.stdout.readline, b''):  # b'' indicates EOF
+        print(line.decode('utf-8'), end='')
+
+def load_environment(filename):
+    with open(filename) as f:
+        return json.load(f)
+
+
+parser = argparse.ArgumentParser()
+parser.add_argument('--cross-target-info-path', dest='target_info')
+parser.add_argument('--cross-destination-path', dest='dst')
+args = parser.parse_args()
+
+cross_target_info_path    = args.target_info
+cross_destination_path    = args.dst
+ctng_config               = cross_target_info_path + '/ct-ng.config'
+cross_destdir             = os.environ['CROSS_DESTDIR']
+
+if not os.path.isdir(cross_destdir):
+    raise Exception("ERROR... expected internal destination for ct-ng does not exist")
+if not os.path.isdir(cross_target_info_path):
+    raise Exception("Supplied configuration info path is not a directory")
+if not os.path.isfile(ctng_config):
+    raise Exception("No crosstool ng configuration file found (ct-ng.config)")
+
+shutil.copy(ctng_config, '/crosstool/.config')
+os.chdir('/crosstool')
+
+runcmd("su crosstoolng -c 'ct-ng source'")
+runcmd("su crosstoolng -c 'ct-ng build'")
+
+# Determine directory of the cross compiler built, then copy the conan profile into it.
+
+cross_compiler_built = None
+if True:
+    entries = os.listdir(cross_destdir)
+    if len(entries) == 1:
+        cross_compiler_built = entries[0]
+
+if cross_compiler_built is None:
+    raise Exception("ERROR... Something went wrong determining where the cross compiler build result is stored.")
+
+runcmd("cp -r " + cross_destdir + "/* " + cross_destination_path + "/")
+runcmd("cp " + cross_target_info_path + '/conan.profile ' + cross_destination_path + '/' + cross_compiler_built + '/conan.profile')
+
+sys.exit(0)

scripts/create-cross-compiler/scripts/entrypoint.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+./create-cross-compiler.py --cross-target-info-path=$CROSS_TARGET_INFO_PATH --cross-destination-path=$CROSS_TARGET_DST_PATH
+