Helpful script to build a copy of Nix 2.0 for ARM (arm-linux-gnueabihf)

nix2-arm-build.sh

#!/bin/bash

# USAGE: docker run -t -i --rm -v $PWD:/out ubuntu:16.04 /out/build.sh

set -eu

# Install
install_packages() {
    apt-get update && apt-get upgrade -yy

    local packages=(
        # Compiler/linker
        binutils-arm-linux-gnueabihf
        gcc-arm-linux-gnueabihf
        g++-arm-linux-gnueabihf

        # Required build tools
        make
        cmake
        autoconf
        automake
        pkg-config
        libtool
        flex
        bison
        gettext

        # Utilities required
        curl
        ca-certificates
        xz-utils

        # For debugging
        less
        silversearcher-ag
        tree
        vim
    )

    apt-get install -yy --no-install-recommends "${packages[@]}"
}

# Download helper function
fetch() {
    local url fileopt

    if [[ $# -eq 2 ]]; then
        fileopt="-o $1"
        url="$2"
    elif [[ $# -eq 1 ]]; then
        fileopt="-O"
        url="$1"
    else
        echo "Bad args"
        exit 1
    fi

    curl -L '-#' $fileopt $url
}

fetch_deps() {
    cd $BUILDROOT/srcs

    echo "Fetching sources..."
    fetch https://zlib.net/zlib-1.2.11.tar.gz
    fetch http://www.bzip.org/1.0.6/bzip2-1.0.6.tar.gz
    fetch https://tukaani.org/xz/xz-5.2.3.tar.gz
    fetch https://www.openssl.org/source/openssl-1.0.2o.tar.gz
    fetch https://curl.haxx.se/download/curl-7.59.0.tar.gz
    fetch https://github.com/nghttp2/nghttp2/releases/download/v1.31.0/nghttp2-1.31.0.tar.gz
    fetch https://www.sqlite.org/2018/sqlite-autoconf-3230000.tar.gz
    fetch https://github.com/seccomp/libseccomp/releases/download/v2.3.3/libseccomp-2.3.3.tar.gz
    fetch https://dl.bintray.com/boostorg/release/1.66.0/source/boost_1_66_0.tar.gz

    # Renamed files.  Note that the nix tarball is a version with the fix for '$CPPFLAGS'
    fetch aws-sdk-cpp-1.4.31.tar.gz     https://github.com/aws/aws-sdk-cpp/archive/1.4.31.tar.gz
    fetch nix-2.0.tar.gz                https://github.com/NixOS/nix/archive/b828051659cf7cac21577982afd3f9314dc2e68c.tar.gz
}

build_zlib() {
    cd $BUILDROOT/build
    tar -xf $BUILDROOT/srcs/zlib-* && cd zlib-*

    CROSS_PREFIX=arm-linux-gnueabihf- \
        CFLAGS="-fPIC" \
        ./configure \
        --prefix=$BUILDROOT/sysroot \
        --static
    make -j4
    make install
}

build_bzip2() {
    cd $BUILDROOT/build
    tar -xf $BUILDROOT/srcs/bzip2-* && cd bzip2-*

    local flags=(
        "CC=arm-linux-gnueabihf-gcc -fPIC"
        "AR=arm-linux-gnueabihf-ar"
        "RANLIB=arm-linux-gnueabihf-ranlib"
    )

    make -j4 "${flags[@]}" libbz2.a
    make "${flags[@]}" PREFIX=$BUILDROOT/sysroot install
}

build_liblzma() {
    cd $BUILDROOT/build
    tar -xf $BUILDROOT/srcs/xz-* && cd xz-*

    ./configure \
        --host=arm-linux-gnueabihf \
        --prefix=$BUILDROOT/sysroot \
        --disable-shared \
        CFLAGS="-fPIC"

    make -j4
    make install
}

build_nghttp2() {
    cd $BUILDROOT/build
    tar -xf $BUILDROOT/srcs/nghttp2-* && cd nghttp2-*

    PKG_CONFIG_PATH=$BUILDROOT/sysroot/lib/pkgconfig \
        ./configure \
        --host=arm-linux-gnueabihf \
        --prefix=$BUILDROOT/sysroot \
        --disable-shared \
        CFLAGS="-fPIC"

    make -j4
    make install
}

build_openssl() {
    cd $BUILDROOT/build
    tar -xf $BUILDROOT/srcs/openssl-* && cd openssl-*

    ./Configure \
        --openssldir=$BUILDROOT/sysroot \
        no-shared \
        os/compiler:arm-linux-gnueabihf-gcc \
        -fPIC

    make -j4 AR='arm-linux-gnueabihf-ar r ' RANLIB=arm-linux-gnueabihf-ranlib
    make install
}

build_curl() {
    cd $BUILDROOT/build
    tar -xf $BUILDROOT/srcs/curl-* && cd curl-*

    ./configure \
        --host=arm-linux-gnueabihf \
        --prefix=$BUILDROOT/sysroot \
        --disable-shared \
        PKG_CONFIG_PATH="$BUILDROOT/sysroot/lib/pkgconfig" \
        CFLAGS="-fPIC"

    make -j4
    make install
}

build_aws_sdk_cpp() {
    cd $BUILDROOT/build
    tar -xf $BUILDROOT/srcs/aws-sdk-cpp-* && cd aws-sdk-cpp-*

    mkdir build && cd build
    cat <<EOF > aws.cmake
set(CMAKE_SYSTEM_NAME Linux)

set(CMAKE_SYSROOT "$BUILDROOT/sysroot")

set(CMAKE_C_COMPILER "arm-linux-gnueabihf-gcc")
set(CMAKE_CXX_COMPILER "arm-linux-gnueabihf-g++")

set(CMAKE_C_FLAGS "\${CMAKE_C_FLAGS} -fPIC")
set(CMAKE_CXX_FLAGS "\${CMAKE_CXX_FLAGS} -fPIC")

# Extra flags require for HTTP/2 support
set(AWS_SDK_ADDITIONAL_LIBRARIES "$BUILDROOT/sysroot/lib/libnghttp2.a")
EOF

    cmake \
        -DCMAKE_BUILD_TYPE=Release \
        -DBUILD_ONLY="config;core;s3" \
        -DCMAKE_TOOLCHAIN_FILE=aws.cmake \
        -DBUILD_SHARED_LIBS=OFF \
        -DCMAKE_INSTALL_PREFIX="$BUILDROOT/sysroot" \
        ..

    make -j2
    make install
}

build_sqlite() {
    cd $BUILDROOT/build
    tar -xf $BUILDROOT/srcs/sqlite-* && cd sqlite-*

    ./configure \
        --prefix=$BUILDROOT/sysroot \
        --host=arm-linux-gnueabihf \
        --disable-shared \
        CFLAGS="-fPIC" \
        CPPFLAGS=-I$BUILDROOT/sysroot/include \
        LDFLAGS=-L$BUILDROOT/sysroot/lib

    make
    make install
}

build_libseccomp() {
    cd $BUILDROOT/build
    tar -xf $BUILDROOT/srcs/libseccomp-* && cd libseccomp-*

    ./configure \
        --prefix=$BUILDROOT/sysroot \
        --host=arm-linux-gnueabihf \
        --disable-shared \
        CFLAGS="-fPIC"

    make
    make install
}

build_boost() {
    cd $BUILDROOT/build
    tar -xf $BUILDROOT/srcs/boost_* && cd boost_*

    ./bootstrap.sh \
        --prefix=$BUILDROOT/sysroot \
        --with-libraries=coroutine,context

    # Enable cross-compilation
    sed -i \
        -e "s|using gcc.*|using gcc : arm : arm-linux-gnueabihf-g++ ;|g" \
        project-config.jam

    # NOTE: The `-a` means "always rebuild"
    ./bjam install \
        cxxflags='-fPIC -std=c++14' \
        cflags=-fPIC \
        link=static \
        architecture=arm \
        variant=release \
        abi=aapcs \
        binary-format=elf \
        threading=multi \
        toolset=gcc \
        -a
}

build_nix() {
    cd $BUILDROOT/build
    tar -xf $BUILDROOT/srcs/nix-* && cd nix-*

    # Handle both from git and from releases
    if [[ ! -f configure ]]; then
        ./bootstrap.sh
    fi

    # NOTE: we need to pass `-std=c++11` (or newer) in $CPPFLAGS so that our
    # autodetection of aws-sdk-cpp works properly
    ./configure \
        --prefix=/usr \
        --host=arm-linux-gnueabihf \
        --disable-doc-gen \
        PKG_CONFIG_PATH="$BUILDROOT/sysroot/lib/pkgconfig" \
        CPPFLAGS="-I$BUILDROOT/sysroot/include -std=c++14" \
        CXXFLAGS='-std=c++14' \
        LDFLAGS="-L$BUILDROOT/sysroot/lib/"

    # Patch various dependency issues
    # TODO: should we submit the LIBS ordering issue upstream?
    sed -i -e 's|-laws-cpp-sdk-s3 -laws-cpp-sdk-core|-laws-cpp-sdk-s3 -laws-cpp-sdk-core -lssl -lcrypto -lz|g' src/libstore/local.mk
    sed -i -e "s|-lbz2|-L$BUILDROOT/sysroot/lib -lbz2|g" src/nix-store/local.mk
    for subdir in nix-copy-closure nix-channel build-remote; do
        sed -i -e 's|LIBS = libmain libutil libformat libstore|LIBS = libmain libformat libstore libutil|g' src/$subdir/local.mk
    done

    # Fix install directory
    # TODO: remove once https://github.com/NixOS/nix/pull/2059 is merged
    sed -i -e 's|install -t $$($(1)_INSTALL_DIR)|install -t $(DESTDIR)$$($(1)_INSTALL_DIR)|g' mk/programs.mk

    # These flags are:
    #   - Build with C++14 (required by Nix)
    #   - Link libnghttp2 along with curl
    #   - Link both libcrypto and libssl in OpenSSL
    #   - Link binaries statically
    #   - Don't build shared libraries (since everything is static)
    #
    local makeflags=(
        "CXXFLAGS=-std=c++14 -I/root/sysroot/include"
        "LIBCURL_LIBS=-L$BUILDROOT/sysroot/lib -lcurl -lnghttp2"
        "OPENSSL_LIBS=-L$BUILDROOT/sysroot/lib -lcrypto -lssl"
        "LDFLAGS=-static"
        "BUILD_SHARED_LIBS=0"
    )
    make -j4 "${makeflags[@]}"
    make "${makeflags[@]}" DESTDIR="$OUTDIR" install
}

main() {
    # Prep and variables
    export BUILDROOT=$HOME
    export OUTDIR=/out/install

    mkdir -p $BUILDROOT/srcs $BUILDROOT/build $BUILDROOT/sysroot
    mkdir -p $OUTDIR

    install_packages
    fetch_deps

    build_zlib
    build_bzip2
    build_liblzma
    build_nghttp2
    build_openssl
    build_curl
    build_aws_sdk_cpp
    build_sqlite
    build_libseccomp
    build_boost
    build_nix

    # Finally, strip everything in the bin directory to reduce the size
    find "$OUTDIR" -type f -executable -exec arm-linux-gnueabihf-strip {} \;
}

main "$@"