make.sh

#!/bin/bash

set -e;
set -u;
set +m;

if [ "$#" -lt 1 ]; then
    echo "Usage: $0 target component [component ...]" >&2;
    echo "       $0 [dist]clean" >&2;
    echo 'Fetch/build SDK components for target.' >&2;
    echo '' >&2;
    echo 'Supported targets:' >&2;
    echo '    all-linux-gnu' >&2;
    echo '    armel-linux-gnu' >&2;
    echo '    armhf-linux-gnu' >&2;
    echo '    arm64-linux-gnu' >&2;
    echo '    x86-linux-gnu' >&2;
    echo '    x86_64-linux-gnu' >&2;
    echo '' >&2;
    echo '    all-linux-musl' >&2;
    echo '    armel-linux-musl' >&2;
    echo '    arm64-linux-musl' >&2;
    echo '    x86-linux-musl' >&2;
    echo '    x86_64-linux-musl' >&2;
    echo '' >&2;
    echo '    all-windows' >&2;
    echo '    armhf-windows' >&2;
    echo '    arm64-windows' >&2;
    echo '    x86-windows' >&2;
    echo '    x86_64-windows' >&2;
    echo '' >&2;
    echo 'Supported components:' >&2;
    echo '    all' >&2;
    echo '    libc' >&2;
    echo '    libc++' >&2;
    echo '    ncurses' >&2;
    exit 1;
fi;

self="./$(basename "$0")";
cd "$(dirname "$0")";
root="$(pwd)";

target="$1";
shift;

arch='none';
mode='unknown';

case "$target" in
    clean)
        if [ -d aux ]; then
            find aux -depth 2 -type d -print0 | xargs -0 -n 1 make clean -C;
        fi;
        if [ -e build ]; then
            echo 'rm -rf build';
            rm -rf build;
        fi;
        exit 0;
        ;;
    distclean)
        if [ -e aux ]; then
            echo 'rm -rf aux';
            rm -rf aux;
        fi;
        if [ -e build ]; then
            echo 'rm -rf build';
            rm -rf build;
        fi;
        if [ -e cache ]; then
            echo 'rm -rf cache';
            rm -rf cache;
        fi;
        exit 0;
        ;;

    all-linux-gnu)
        for arch in armel armhf arm64 x86 x86_64; do
            "$self" "$arch-linux-gnu" "$@";
        done;
        exit 0;
        ;;
    *-linux-gnu)
        if ! hash curl &>/dev/null; then
            echo 'Need curl.' >&2;
            exit 1;
        fi;
        mode='deb';
        arch="${target%-linux-gnu}";
        ;;

    all-linux-musl)
        for arch in armel arm64 x86 x86_64; do
            "$self" "$arch-linux-musl" "$@";
        done;
        exit 0;
        ;;
    *-linux-musl)
        mode='build-linux';
        arch="${target%-linux-musl}";
        ;;

    all-windows)
        for arch in armhf arm64 x86 x86_64; do
            "$self" "$arch-windows" "$@";
        done;
        exit 0;
        ;;
    *-windows)
        mode='build-windows';
        arch="${target%-windows}";
        ;;

    # Undocumented
    all-linux-gnu-dev)
        for arch in arm64 x86_64; do
            "$self" "$arch-linux-gnu-dev" "$@";
        done;
        exit 0;
        ;;
    *-linux-gnu-dev)
        if ! hash curl &>/dev/null; then
            echo 'Need curl.' >&2;
            exit 1;
        fi;
        mode='deb';
        arch="${target%-linux-gnu-dev}-dev";
        ;;

    *)
        echo "Unsupported target: $target" >&2;
        exit 1;
        ;;
esac;

if [ "$#" -lt 1 ]; then
    echo "No components given." >&2;
    exit 1;
fi;

if [ -z "${NUM_JOBS+x}" ]; then
    NUM_JOBS='';
fi;

install_kernel_headers()
{
    pushd "$1" >/dev/null;
    find . -name '*.h' | while read -r; do
        f="$2/$REPLY";
        mkdir -p "$(dirname "$f")";
        sed -E 's/([ \t(])(__user|__force|__iomem)[ \t]/\1/g;s/__attribute_const__([ \t]|$)/\1/g;s@^#include <linux/compiler.h>@@;s/(^|[^a-zA-Z0-9])__packed([^a-zA-Z0-9_]|$)/\1__attribute__((packed))\2/g;s/(^|[ \t(])(inline|asm|volatile)([ \t(]|$)/\1__\2__\3/g;s@#(ifndef|define|endif[ \t]*/[*])[ \t]*_UAPI@#\1 @' "$REPLY" | unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__ -o "$f" || if [ "$?" -eq 2 ]; then exit 1; fi;
    done;
    popd >/dev/null;
}

prefix="build/$target";

case "$mode" in
    build-linux)
        if ! [ -z "${LLVM_CONFIG+x}" ]; then
            bindir="$("$LLVM_CONFIG" --bindir)";
            if [ -z "${CLANG+x}" ]; then
                CLANG="$bindir/clang";
            fi;
            if [ -z "${CLANGXX+x}" ]; then
                CLANGXX="$bindir/clang++";
            fi;
            if [ -z "${LLD+x}" ]; then
                LLD="$bindir/ld.lld";
            fi;
            if [ -z "${AR+x}" ]; then
                AR="$bindir/llvm-ar";
            fi;
            if [ -z "${RANLIB+x}" ]; then
                RANLIB="$bindir/llvm-ranlib";
            fi;
        else
            LLVM_CONFIG='llvm-config';
        fi;
        if [ -z "${CLANG+x}" ]; then
            CLANG='clang';
        fi;
        if [ -z "${CLANGXX+x}" ]; then
            CLANGXX='clang++';
        fi;
        if [ -z "${LLD+x}" ]; then
            LLD="lld";
        fi;
        if [ -z "${AR+x}" ]; then
            AR='llvm-ar';
        fi;
        if [ -z "${RANLIB+x}" ]; then
            RANLIB='llvm-ranlib';
        fi;

        ARCH_FLAGS=();
        case "$arch" in
            armel)
                triplet='armv6-linux-musleabi';
                abi_triplet='arm-linux-musleabi';
                ;;
            arm64)
                triplet='aarch64-linux-musl';
                abi_triplet="$triplet";
                ;;
            x86)
                triplet='i386-linux-musl';
                abi_triplet="$triplet";
                ARCH_FLAGS+=('-march=i486');
                ;;
            x86_64)
                triplet='x86_64-linux-musl';
                abi_triplet="$triplet";
                ;;
            *)
                echo "Unsupported architecture: $arch" >&2;
                exit 1;
                ;;
        esac;
        CC_FLAGS=('-O3' "--target=$triplet");
        LD_FLAGS=("-fuse-ld=$LLD");
        CFG_FLAGS=("--host=$triplet" "--prefix=$root/$prefix");
        # Must be after --target
        if [ "${#ARCH_FLAGS}" -gt 0 ]; then
            CC_FLAGS+=("${ARCH_FLAGS[@]}");
        fi;
        # Must be after target and arch
        CC_FLAGS+=('-flto' "--sysroot=$root/$prefix");
        CXX_FLAGS=("${CC_FLAGS[@]}");
        if ! [ -z "${CFLAGS+x}" ]; then
            CC_FLAGS+=($CFLAGS); # no quotes
        fi;
        if ! [ -z "${CXXFLAGS+x}" ]; then
            CXX_FLAGS+=($CXXFLAGS); # no quotes
        fi;
        if ! [ -z "${LDFLAGS+x}" ]; then
            LD_FLAGS+=($LDFLAGS); # no quotes
        fi;
        CRT_FLAGS=('--rtlib=compiler-rt' "-resource-dir=$root/$prefix/lib/clang");

        components=("$@");
        if [ "${#components[@]}" -eq 1 ] && [ "${components[0]}" = 'all' ]; then
            components=('libc' 'libc++' 'ncurses');
        fi;
        for component in "${components[@]}"; do
            case "$component" in
                libc)
                    # Kernel headers
                    echo 'Installing kernel headers...';
                    install_kernel_headers 'src/linux/include/uapi' "../../../../$prefix/include";
                    case "$arch" in
                        armel)
                            folder='arm';
                            ;;
                        arm64)
                            folder='arm64';
                            ;;
                        x86|x86_64)
                            folder='x86';
                            ;;
                    esac;
                    install_kernel_headers "src/linux/arch/$folder/include/uapi" "../../../../../../$prefix/include/$abi_triplet";

                    # Fix up symlinks
                    pushd "$prefix/include" >/dev/null;
                    ln -sf "$abi_triplet/asm" 'asm';
                    cd "$abi_triplet/asm";
                    find '../../asm-generic' -name '*.h' | while read -r; do
                        if [ "${REPLY:0:18}" != '../../asm-generic/' ]; then
                            echo "Error: 'find' output starts with invalid prefix." >&2;
                            exit 1;
                        fi;
                        f="${REPLY:18}";
                        if ! [ -e "$f" ]; then
                            ln -s "$REPLY" "$f";
                        fi;
                    done;
                    popd >/dev/null;

                    # Musl
                    mkdir -p "aux/$target/musl";
                    pushd "aux/$target/musl" >/dev/null;
                    ../../../src/musl/configure --enable-static --disable-shared "${CFG_FLAGS[@]}" CC="$CLANG" CFLAGS="${CC_FLAGS[*]}" AR="$AR" RANLIB="$RANLIB";
                    make "-j$NUM_JOBS";
                    make install;
                    popd >/dev/null;

                    # Compiler-rt
                    mkdir -p "aux/$target/compiler-rt";
                    pushd "aux/$target/compiler-rt" >/dev/null;
                    cmake ../../../src/llvm/compiler-rt \
                        -DCMAKE_INSTALL_PREFIX:PATH="$root/$prefix/lib/clang" \
                        -DCMAKE_TRY_COMPILE_TARGET_TYPE:STRING=STATIC_LIBRARY \
                        -DCMAKE_SYSTEM_NAME:STRING='Linux' \
                        -DCMAKE_C_COMPILER:STRING="$CLANG" \
                        -DCMAKE_C_COMPILER_TARGET:STRING="$abi_triplet" \
                        -DCMAKE_C_FLAGS:STRING="${CC_FLAGS[*]}" \
                        -DCMAKE_ASM_COMPILER:STRING="$CLANG" \
                        -DCMAKE_ASM_COMPILER_TARGET:STRING="$abi_triplet" \
                        -DCMAKE_ASM_FLAGS:STRING="${CC_FLAGS[*]}" \
                        -DCMAKE_EXE_LINKER_FLAGS:STRING="${LD_FLAGS[*]}" \
                        -DCMAKE_AR:STRING="$AR" \
                        -DCMAKE_RANLIB:STRING="$RANLIB" \
                        -DLLVM_CONFIG_PATH:STRING="$LLVM_CONFIG" \
                        -DCOMPILER_RT_DEFAULT_TARGET_ONLY:BOOL='ON' \
                        -DCOMPILER_RT_BUILD_BUILTINS:BOOL='ON' \
                        -DCOMPILER_RT_BUILD_CRT:BOOL='ON' \
                        -DCOMPILER_RT_BUILD_SANITIZERS:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_CTX_PROFILE:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_XRAY:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_LIBFUZZER:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_PROFILE:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_MEMPROF:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_ORC:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_GWP_ASAN:BOOL='OFF' \
                        -DCOMPILER_RT_ENABLE_CET:BOOL='OFF' \
                        ;
                    make "-j$NUM_JOBS";
                    make install;
                    popd >/dev/null;
                    ;;

                libc++)
                    mkdir -p "aux/$target/libcxx";
                    pushd "aux/$target/libcxx" >/dev/null;
                    cmake ../../../src/llvm/runtimes \
                        -DCMAKE_INSTALL_PREFIX:PATH="$root/$prefix" \
                        -DCMAKE_TRY_COMPILE_TARGET_TYPE:STRING=STATIC_LIBRARY \
                        -DCMAKE_SYSTEM_NAME:STRING='Linux' \
                        -DCMAKE_C_COMPILER:STRING="$CLANG" \
                        -DCMAKE_C_COMPILER_TARGET:STRING="$abi_triplet" \
                        -DCMAKE_C_FLAGS:STRING="${CC_FLAGS[*]}" \
                        -DCMAKE_CXX_COMPILER:STRING="$CLANGXX" \
                        -DCMAKE_CXX_COMPILER_TARGET:STRING="$abi_triplet" \
                        -DCMAKE_CXX_FLAGS:STRING="${CXX_FLAGS[*]}" \
                        -DCMAKE_ASM_COMPILER:STRING="$CLANG" \
                        -DCMAKE_ASM_COMPILER_TARGET:STRING="$abi_triplet" \
                        -DCMAKE_ASM_FLAGS:STRING="${CC_FLAGS[*]}" \
                        -DCMAKE_EXE_LINKER_FLAGS:STRING="${LD_FLAGS[*]}" \
                        -DCMAKE_AR:STRING="$AR" \
                        -DCMAKE_RANLIB:STRING="$RANLIB" \
                        -DLLVM_ENABLE_RUNTIMES="libunwind;libcxxabi;libcxx" \
                        -DLIBUNWIND_ENABLE_SHARED:BOOL='OFF' \
                        -DLIBUNWIND_ENABLE_STATIC:BOOL='ON' \
                        -DLIBUNWIND_USE_COMPILER_RT:BOOL='ON' \
                        -DLIBCXXABI_ENABLE_SHARED:BOOL='OFF' \
                        -DLIBCXXABI_ENABLE_STATIC:BOOL='ON' \
                        -DLIBCXXABI_USE_COMPILER_RT:BOOL='ON' \
                        -DLIBCXXABI_USE_LLVM_UNWINDER:BOOL='ON' \
                        -DLIBCXXABI_ENABLE_STATIC_UNWINDER:BOOL='ON' \
                        -DLIBCXX_ENABLE_SHARED:BOOL='OFF' \
                        -DLIBCXX_ENABLE_STATIC:BOOL='ON' \
                        -DLIBCXX_USE_COMPILER_RT:BOOL='ON' \
                        -DLIBCXX_HAS_MUSL_LIBC:BOOL='ON' \
                        -DLIBCXX_INCLUDE_BENCHMARKS:BOOL='OFF' \
                        -DLIBCXX_HARDENING_MODE:STRING='fast' \
                        ;
                    make "-j$NUM_JOBS";
                    make install;
                    popd >/dev/null;
                    ;;

                ncurses)
                    mkdir -p "aux/$target/ncurses";
                    pushd "aux/$target/ncurses" >/dev/null;
                    ../../../src/ncurses/configure --without-shared --without-debug --with-normal --enable-overwrite --without-ada --without-cxx --without-cxx-binding --disable-db-install --without-manpages --without-progs --without-tack --without-tests --disable-pc-files "${CFG_FLAGS[@]}" CC="$CLANG" CFLAGS="${CC_FLAGS[*]}" CPPFLAGS="${CC_FLAGS[*]}" LDFLAGS="${LD_FLAGS[*]} ${CRT_FLAGS[*]}" AR="$AR" RANLIB="$RANLIB";
                    make "-j$NUM_JOBS";
                    make install;
                    popd >/dev/null;
                    ;;

                *)
                    echo "Unsupported component: $component" >&2;
                    exit 1;
                    ;;
            esac;
        done;
        ;;

    build-windows)
        if ! [ -z "${LLVM_CONFIG+x}" ]; then
            bindir="$("$LLVM_CONFIG" --bindir)";
            if [ -z "${CLANG+x}" ]; then
                CLANG="$bindir/clang";
            fi;
            if [ -z "${CLANGXX+x}" ]; then
                CLANGXX="$bindir/clang++";
            fi;
            if [ -z "${LLD+x}" ]; then
                LLD="$bindir/ld.lld";
            fi;
            if [ -z "${AS+x}" ]; then
                AS="$bindir/as";
            fi;
            if [ -z "${AR+x}" ]; then
                AR="$bindir/llvm-ar";
            fi;
            if [ -z "${RANLIB+x}" ]; then
                RANLIB="$bindir/llvm-ranlib";
            fi;
            if [ -z "${STRIP+x}" ]; then
                STRIP="$bindir/llvm-strip";
            fi;
            if [ -z "${DLLTOOL+x}" ]; then
                DLLTOOL="$bindir/llvm-dlltool";
            fi;
            if [ -z "${RC+x}" ]; then
                RC="$bindir/llvm-windres";
            fi;
        else
            LLVM_CONFIG='llvm-config';
        fi;
        if [ -z "${CLANG+x}" ]; then
            CLANG='clang';
        fi;
        if [ -z "${CLANGXX+x}" ]; then
            CLANGXX='clang++';
        fi;
        if [ -z "${LLD+x}" ]; then
            LLD="lld";
        fi;
        if [ -z "${AS+x}" ]; then
            AS='llvm-as';
        fi;
        if [ -z "${AR+x}" ]; then
            AR='llvm-ar';
        fi;
        if [ -z "${RANLIB+x}" ]; then
            RANLIB='llvm-ranlib';
        fi;
        if [ -z "${STRIP+x}" ]; then
            STRIP='llvm-strip';
        fi;
        if [ -z "${DLLTOOL+x}" ]; then
            DLLTOOL='llvm-dlltool';
        fi;
        if [ -z "${RC+x}" ]; then
            RC='llvm-windres';
        fi;

        ARCH_FLAGS=();
        case "$arch" in
            armhf)
                triplet='armv7-w64-mingw32';
                abi_triplet='arm-w64-mingw32';
                ;;
            arm64)
                triplet='aarch64-w64-mingw32';
                abi_triplet="$triplet";
                ;;
            x86)
                triplet='i686-w64-mingw32';
                abi_triplet="$triplet";
                ;;
            x86_64)
                triplet='x86_64-w64-mingw32';
                abi_triplet="$triplet";
                ;;
            *)
                echo "Unsupported architecture: $arch" >&2;
                exit 1;
                ;;
        esac;
        CC_FLAGS=('-O3' "--target=$triplet");
        LD_FLAGS=("-fuse-ld='$LLD'");
        CFG_FLAGS=("--host=$triplet" "--prefix=$root/$prefix");
        # Must be after --target
        if [ "${#ARCH_FLAGS}" -gt 0 ]; then
            CC_FLAGS+=("${ARCH_FLAGS[@]}");
        fi;
        # Must be after target and arch
        CC_FLAGS+=('-flto' "--sysroot=$root/$prefix");
        CXX_FLAGS=("${CC_FLAGS[@]}");
        if ! [ -z "${CFLAGS+x}" ]; then
            CC_FLAGS+=($CFLAGS); # no quotes
        fi;
        if ! [ -z "${CXXFLAGS+x}" ]; then
            CXX_FLAGS+=($CXXFLAGS); # no quotes
        fi;
        if ! [ -z "${LDFLAGS+x}" ]; then
            LD_FLAGS+=($LDFLAGS); # no quotes
        fi;
        CRT_FLAGS=('--rtlib=compiler-rt' "-resource-dir=$root/$prefix/lib/clang" "-I$("$CLANG" -print-resource-dir)/include");

        components=("$@");
        if [ "${#components[@]}" -eq 1 ] && [ "${components[0]}" = 'all' ]; then
            components=('libc'); # TODO: libc++ ncurses
        fi;
        for component in "${components[@]}"; do
            case "$component" in
                libc)
                    # MinGW
                    mkdir -p "aux/$target/mingw-hdr";
                    pushd "aux/$target/mingw-hdr" >/dev/null;
                    ../../../src/mingw/configure --with-headers --without-crt "${CFG_FLAGS[@]}" CC="$CLANG" CFLAGS="${CC_FLAGS[*]}" CXX="$CLANGXX" CXXFLAGS="${CXX_FLAGS[*]}" AS="$AS" AR="$AR" RANLIB="$RANLIB" STRIP="$STRIP" DLLTOOL="$DLLTOOL" RC="$RC" RCFLAGS="--target=$abi_triplet --include-dir=$root/$prefix/include";
                    make "-j$NUM_JOBS";
                    make install;
                    popd >/dev/null;

                    mkdir -p "aux/$target/mingw-crt";
                    pushd "aux/$target/mingw-crt" >/dev/null;
                    ../../../src/mingw/configure --without-headers --with-crt --with-libraries=winpthreads --enable-static --disable-shared "${CFG_FLAGS[@]}" CC="$CLANG" CFLAGS="${CC_FLAGS[*]}" CXX="$CLANGXX" CXXFLAGS="${CXX_FLAGS[*]}" AS="$AS" AR="$AR" RANLIB="$RANLIB" STRIP="$STRIP" DLLTOOL="$DLLTOOL" RC="$RC" RCFLAGS="--target=$abi_triplet --include-dir=$root/$prefix/include";
                    make "-j$NUM_JOBS";
                    make install;
                    popd >/dev/null;

                    # Compiler-rt
                    mkdir -p "aux/$target/compiler-rt";
                    pushd "aux/$target/compiler-rt" >/dev/null;
                    cmake ../../../src/llvm/compiler-rt \
                        -DCMAKE_INSTALL_PREFIX:PATH="$root/$prefix/lib/clang" \
                        -DCMAKE_TRY_COMPILE_TARGET_TYPE:STRING=STATIC_LIBRARY \
                        -DCMAKE_SYSTEM_NAME:STRING='Windows' \
                        -DCMAKE_STATIC_LIBRARY_PREFIX_C:STRING='lib' \
                        -DCMAKE_STATIC_LIBRARY_PREFIX_CXX:STRING='lib' \
                        -DCMAKE_STATIC_LIBRARY_SUFFIX_C:STRING='.a' \
                        -DCMAKE_STATIC_LIBRARY_SUFFIX_CXX:STRING='.a' \
                        -DCMAKE_C_COMPILER:STRING="$CLANG" \
                        -DCMAKE_C_COMPILER_TARGET:STRING="$abi_triplet" \
                        -DCMAKE_C_FLAGS:STRING="${CC_FLAGS[*]}" \
                        -DCMAKE_ASM_COMPILER:STRING="$CLANG" \
                        -DCMAKE_ASM_COMPILER_TARGET:STRING="$abi_triplet" \
                        -DCMAKE_ASM_FLAGS:STRING="${CC_FLAGS[*]}" \
                        -DCMAKE_EXE_LINKER_FLAGS:STRING="${LD_FLAGS[*]}" \
                        -DCMAKE_AR:STRING="$AR" \
                        -DCMAKE_RANLIB:STRING="$RANLIB" \
                        -DLLVM_CONFIG_PATH:STRING="$LLVM_CONFIG" \
                        -DCOMPILER_RT_DEFAULT_TARGET_ONLY:BOOL='ON' \
                        -DCOMPILER_RT_BUILD_BUILTINS:BOOL='ON' \
                        -DCOMPILER_RT_BUILD_CRT:BOOL='ON' \
                        -DCOMPILER_RT_BUILD_SANITIZERS:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_CTX_PROFILE:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_XRAY:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_LIBFUZZER:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_PROFILE:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_MEMPROF:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_ORC:BOOL='OFF' \
                        -DCOMPILER_RT_BUILD_GWP_ASAN:BOOL='OFF' \
                        -DCOMPILER_RT_ENABLE_CET:BOOL='OFF' \
                        -DCOMPILER_RT_BUILTINS_ENABLE_PIC:BOOL='OFF' \
                        ;
                    make "-j$NUM_JOBS";
                    make install;
                    popd >/dev/null;
                    ;;

                *)
                    echo "Unsupported component: $component" >&2;
                    exit 1;
                    ;;
            esac;
        done;
        ;;

    deb)
        mkdir -p "$prefix";
        mkdir -p "cache";

        components=("$@");
        if [ "${#components[@]}" -eq 1 ] && [ "${components[0]}" = 'all' ]; then
            lists=("res/packages-"*"-$arch.txt");
        else
            lists=("${components[@]/#/res/packages-}");
            lists=("${lists[@]/%/-$arch.txt}");
        fi;
        for list in "${lists[@]}"; do

            # http://archive.debian.org/debian-archive/debian/dists/jessie/main/
            # http://archive.debian.org/debian-archive/debian/dists/bullseye/main/
            if ! [ -e "$list" ]; then
                echo "Error: package list $list doesn't exist." >&2;
                exit 1;
            fi;

            debs=();
            while read -r; do
                url="$REPLY";
                deb="$(basename "$url")";
                echo "$deb";
                deb="cache/$deb";
                if ! [ -e "$deb" ]; then
                    curl -s -S -f -L --connect-timeout 3 --speed-time 30 --speed-limit 131072 -o "$deb" "$url" &
                fi;
                debs+=("$deb");
            done <"$list";
            wait;

            for deb in "${debs[@]}"; do
                data="$(ar t "$deb" | egrep '^data.tar.\w+$')";
                if [ "$(wc -l <<<"$data")" -ne 1 ]; then
                    echo "Error: deb $deb does not contain exactly one data.tar.* file." >&2;
                    exit 1;
                fi;
                flag='';
                case "${data#data.tar.}" in
                    bz2)
                        flag='-j';
                        ;;
                    gz)
                        flag='-z';
                        ;;
                    lzma)
                        flag='--lzma';
                        ;;
                    xz)
                        flag='-J';
                        ;;
                    *)
                        echo "Error: unknown compression format in $data";
                        ;;
                esac;
                ar p "$deb" "$data" | tar -x "$flag" -f - -C "$prefix";
            done;
        done;
        tools/rewrite-symlinks.sh "$prefix" >/dev/null;
        ;;

    *)
        echo "Bug: unknown mode $mode" >&2;
        exit 1;
        ;;
esac;