Allow VS Code Server to run on older Linux

!VS Code on older Linux.md

Allow VS Code Server to run on older Linux

https://code.visualstudio.com/docs/remote/faq#_can-i-run-vs-code-server-on-older-linux-distributions

The above "documentation" appears to be untested or verified. So here's an attempt to actually make crosstool-NG actually work.

Requirements

• docker with buildx
• PermitUserEnvironment yes in /etc/ssh/sshd_config

Installation

Run this on the older linux system you are remoting into via ssh:

• ./build-sysroot.sh

It will build the sysroot in docker, then install it to ~/.vscode-sysroot, and finally update your ~/.ssh/environment.

build-sysroot.sh

#! /usr/bin/env bash
#
# Allow VSCode Server to run on older Linux.
#
set -e
set -u
# set -x

# what Ubuntu 24/noble release
NOBLEREL=20251013

# crosstool-NG
CTVER=1.28.0

# gcc/glibc
GCCVER=10.5.0
GLIBCVER=2.28

# patchelf
PEVER=0.18.0

ARCH=$(uname --machine)
printf -v NOW '%(%FT%H:%M)T'

main() {

    if ! docker buildx ls |grep -q ^nocliplogs
    then
        docker buildx create --name nocliplogs \
            --driver-opt env.BUILDKIT_STEP_LOG_MAX_SIZE=-1 \
            --driver-opt env.BUILDKIT_STEP_LOG_MAX_SPEED=-1
    fi

    if [[ ! -e "$HOME/.vscode-sysroot" ]]
    then
        docker buildx build --builder nocliplogs --progress=plain \
            --build-arg NOBLEREL="$NOBLEREL" \
            --build-arg CTVER="$CTVER" \
            --build-arg GCCVER="$GCCVER" \
            --build-arg GLIBCVER="$GLIBCVER" \
            --build-arg ARCH="$ARCH" \
            --target=export-sysroot --output=type=local,dest="$HOME" .

    fi

    if [[ ! -x "$HOME/.vscode-sysroot/bin/patchelf" ]]
    then
        pushd "$HOME/.vscode-sysroot"
        PEDL="https://github.com/NixOS/patchelf/releases/download/$PEVER/patchelf-$PEVER-$ARCH.tar.gz"
        curl --location "$PEDL" |
            tar --extract --gzip --wildcards '*/bin' '*/share'
        popd
    fi

    if [[ -e "$HOME/.ssh/environment" ]]
    then
        
        cp -p "$HOME/.ssh/environment" "$HOME/.ssh/environment.$NOW"
        grep -v VSCODE_SERVER_ "$HOME/.ssh/environment.$NOW" >"$HOME/.ssh/environment" ||:
    fi
    cat >>"$HOME/.ssh/environment" <<-EOF
	VSCODE_SERVER_CUSTOM_GLIBC_LINKER="$HOME/.vscode-sysroot/lib/ld-linux-${ARCH/_/-}.so.${GLIBCVER::1}"
	VSCODE_SERVER_CUSTOM_GLIBC_PATH="$HOME/.vscode-sysroot/usr/lib"
	VSCODE_SERVER_PATCHELF_PATH="$HOME/.vscode-sysroot/bin/patchelf"
	EOF

    # shellcheck disable=SC1091
    source "$HOME/.ssh/environment"
    test -e "$VSCODE_SERVER_CUSTOM_GLIBC_LINKER" ||
        echo "ERROR: Missing file VSCODE_SERVER_CUSTOM_GLIBC_LINKER: $VSCODE_SERVER_CUSTOM_GLIBC_LINKER"
    test -d "$VSCODE_SERVER_CUSTOM_GLIBC_PATH" ||
        echo "ERROR: Missing file VSCODE_SERVER_CUSTOM_GLIBC_PATH: $VSCODE_SERVER_CUSTOM_GLIBC_PATH"
    test -x "$VSCODE_SERVER_PATCHELF_PATH" ||
        echo "ERROR: Missing file VSCODE_SERVER_PATCHELF_PATH: $VSCODE_SERVER_PATCHELF_PATH"

    if ! grep '^PermitUserEnvironment yes$' /etc/ssh/sshd_config
    then
        echo 'Make sure /etc/ssh/sshd_config has PermitUserEnvironment yes'
        echo 'and sshd is restarted.'
    fi
}

main
exit

Dockerfile

# Required env vars:
#  - NOBLEREL: The docker container release of Ubuntu 24LTS (noble).
#  - CTVER: The crosstool-NG version.
#  - GCCVER: The GNU Compiler Collection version.
#  - GLIBCVER: The GNU C Library version.
#  - ARCH: Machine archictecture.

ARG NOBLEREL

# ======================================================================
FROM ubuntu:noble-$NOBLEREL AS build-sysroot

ARG DEBIAN_FRONTEND=noninteractive

RUN apt-get update \
    && \
    apt-get install --yes --no-install-recommends \
        automake \
        bison \
        bzip2 \
        ca-certificates \
        file \
        flex \
        g++ \
        gawk \
        help2man \
        libncurses-dev \
        libtool-bin \
        make \
        patch \
        texinfo \
        unzip \
        wget \
        xz-utils \
    && :

RUN --mount=type=cache,target=/home/ubuntu/build/downloads,sharing=locked \
    --mount=type=cache,target=/home/ubuntu/build/.build,sharing=locked \
    mkdir --parents /home/ubuntu/build/downloads \
    && \
    chown --recursive ubuntu:ubuntu /home/ubuntu/build

# ----------------------------------------------------------------------
USER ubuntu
WORKDIR /home/ubuntu

ARG CTVER
ARG CTDL="http://crosstool-ng.org/download/crosstool-ng/crosstool-ng-$CTVER.tar.xz"

RUN wget --output-document=- "$CTDL" |tar --extract --xz --directory="$HOME"
RUN cd "$HOME/crosstool-ng-$CTVER" \
    && \
    ./configure --prefix="$HOME" \
    && \
    make -j \
    && \
    make install

WORKDIR /home/ubuntu/build

ARG ARCH
ARG GCCVER
ARG GLIBCVER
ARG VLBA="https://raw.githubusercontent.com/microsoft/vscode-linux-build-agent"
ARG CONFDL="$VLBA/refs/heads/main/$ARCH-gcc-$GCCVER-glibc-$GLIBCVER.config"

RUN wget --output-document=.config "$CONFDL" \
    && \
    echo "CT_PARALLEL_JOBS=$(nproc)" >>.config \
    && \
    echo 'CT_DEBUG_GDB=n' >>.config \
    && \
    $HOME/bin/ct-ng olddefconfig \
    && \
    $HOME/bin/ct-ng build

RUN find "$ARCH-linux-gnu/$ARCH-linux-gnu/sysroot" \
    -type d -print0 |xargs -r0 chmod u+w

# ======================================================================
FROM scratch AS export-sysroot

ARG ARCH

COPY --from=build-sysroot \
    /home/ubuntu/build/$ARCH-linux-gnu/$ARCH-linux-gnu/sysroot \
    /.vscode-sysroot
COPY --from=build-sysroot \
    /home/ubuntu/build/.config /.vscode-sysroot/