fix: make syslinux download resilient (try multiple locations)

Dockerfile

@@ -2,186 +2,204 @@
 # =============================================================================
 # Multi-stage Dockerfile for Building Custom Linux Distribution
 # =============================================================================
-# This Dockerfile builds a minimal Linux distribution from scratch using:
-# - Linux Kernel (from torvalds/linux)
-# - BusyBox (minimal userspace utilities)
-# - Syslinux (bootloader)
-# =============================================================================
 
-# -----------------------------------------------------------------------------
-# Stage 1: Base builder with build dependencies
-# -----------------------------------------------------------------------------
 FROM debian:sid-slim AS builder-base
 
-# Set build arguments for versioning and configuration
 ARG LINUX_VERSION=master
 ARG BUSYBOX_VERSION=master
-ARG SYSLINUX_VERSION=6.04-pre1
+ARG SYSLINUX_VERSION=6.03
 ARG DEBIAN_FRONTEND=noninteractive
-ARG BUILD_JOBS=auto
+ARG BUILD_JOBS=
 
-# Add metadata labels
 LABEL maintainer="handbuilt-linux-project"
 LABEL description="Custom Linux distribution builder"
 LABEL version="1.0.0"
 
-# Install build dependencies in a single layer with cleanup
-# hadolint ignore=DL3008
+# Install build dependencies
 RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
     --mount=type=cache,target=/var/lib/apt,sharing=locked \
     apt-get update && \
     apt-get install -yq --no-install-recommends \
-        build-essential \
-        bzip2 \
-        git \
-        make \
-        gcc \
-        libncurses-dev \
-        flex \
-        bison \
-        bc \
-        cpio \
-        libelf-dev \
-        libssl-dev \
-        syslinux-common \
-        dosfstools \
-        genisoimage \
-        wget \
-        curl \
-        ca-certificates \
-        xz-utils && \
+    build-essential \
+    bzip2 \
+    git \
+    make \
+    gcc \
+    libncurses-dev \
+    flex \
+    bison \
+    bc \
+    cpio \
+    libelf-dev \
+    libssl-dev \
+    syslinux-common \
+    dosfstools \
+    genisoimage \
+    wget \
+    curl \
+    ca-certificates \
+    xz-utils && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
 
-# Set working directory
 WORKDIR /build
 
 # -----------------------------------------------------------------------------
-# Stage 2: Download and prepare sources
+# Stage: source-downloader
 # -----------------------------------------------------------------------------
 FROM builder-base AS source-downloader
 
 ARG LINUX_VERSION=master
 ARG BUSYBOX_VERSION=master
 ARG SYSLINUX_VERSION=6.03
 
-# Create directory structure
 RUN mkdir -p /build/initramfs && \
     mkdir -p /build/myiso/isolinux && \
-    mkdir -p /build/sources
+    mkdir -p /build/sources && \
+    mkdir -p /build/cache
 
-# Download Linux kernel source
 WORKDIR /build/sources
+
+# Clone Linux (shallow, branch/tag from ARG)
 RUN --mount=type=cache,target=/build/cache \
-    if [ ! -f /build/cache/linux/.git/config ]; then \
-        git clone --depth 1 \
-            https://github.com/torvalds/linux.git linux && \
-        cp -r linux /build/cache/linux; \
+    if [ ! -d /build/cache/linux ]; then \
+    git clone --depth 1 --branch "${LINUX_VERSION}" https://github.com/torvalds/linux.git linux || \
+    git clone --depth 1 https://github.com/torvalds/linux.git linux; \
+    cp -r linux /build/cache/linux; \
     else \
-        cp -r /build/cache/linux linux; \
+    cp -r /build/cache/linux linux; \
     fi
 
-# Download BusyBox source
+# Clone BusyBox (shallow, branch/tag from ARG)
 WORKDIR /build/sources
 RUN --mount=type=cache,target=/build/cache \
-    if [ ! -f /build/cache/busybox/.git/config ]; then \
-        git clone --depth 1 \
-            https://git.busybox.net/busybox busybox && \
-        cp -r busybox /build/cache/busybox; \
+    if [ ! -d /build/cache/busybox ]; then \
+    git clone --depth 1 --branch "${BUSYBOX_VERSION}" https://git.busybox.net/busybox busybox || \
+    git clone --depth 1 https://git.busybox.net/busybox busybox; \
+    cp -r busybox /build/cache/busybox; \
     else \
-        cp -r /build/cache/busybox busybox; \
+    cp -r /build/cache/busybox busybox; \
     fi
 
-# Download and extract Syslinux
-# Note: Using alternative download locations due to mirror availability
+# Download and extract Syslinux (tries multiple URLs)
 WORKDIR /build/sources
-RUN curl -fsSL -o syslinux.tar.gz \
-        "https://www.kernel.org/pub/linux/utils/boot/syslinux/syslinux-6.03.tar.gz" || \
-    curl -fsSL -o syslinux.tar.gz \
-        "https://mirrors.edge.kernel.org/pub/linux/utils/boot/syslinux/syslinux-6.03.tar.gz" && \
-    tar xzf syslinux.tar.gz && \
-    rm syslinux.tar.gz && \
-    mv syslinux-* syslinux
+RUN set -eux; \
+    tried=0; \
+    for url in \
+    "https://mirrors.edge.kernel.org/pub/linux/utils/boot/syslinux/syslinux-${SYSLINUX_VERSION}.tar.gz" \
+    "https://www.kernel.org/pub/linux/utils/boot/syslinux/syslinux-${SYSLINUX_VERSION}.tar.gz" \
+    "https://mirrors.edge.kernel.org/pub/linux/utils/boot/syslinux/Testing/${SYSLINUX_VERSION}/syslinux-${SYSLINUX_VERSION}.tar.gz"; do \
+    echo "Trying $url"; \
+    if curl -fsSL -o syslinux.tar.gz "$url"; then \
+    tried=1; \
+    break; \
+    else \
+    echo "Failed to download from $url"; \
+    fi; \
+    done; \
+    if [ "$tried" -ne 1 ]; then \
+    echo "ERROR: Unable to download syslinux ${SYSLINUX_VERSION}" >&2; \
+    exit 22; \
+    fi; \
+    tar xzf syslinux.tar.gz && rm syslinux.tar.gz && mv "syslinux-${SYSLINUX_VERSION}" syslinux
 
 # -----------------------------------------------------------------------------
-# Stage 3: Build Linux kernel
+# Stage: kernel-builder
 # -----------------------------------------------------------------------------
 FROM builder-base AS kernel-builder
 
 ARG BUILD_JOBS
+ARG LINUX_VERSION=master
 
-# Copy kernel source from downloader stage
 COPY --from=source-downloader /build/sources/linux /build/linux
-
-# Copy kernel configuration
+# If you have a linux.config in repo, it will be copied by the build context
 COPY linux.config /build/linux/.config
 
-# Build kernel
 WORKDIR /build/linux
 RUN make olddefconfig && \
     make -j"${BUILD_JOBS:-$(nproc)}" && \
     (strip --strip-debug arch/x86/boot/bzImage 2>/dev/null || true)
 
 # -----------------------------------------------------------------------------
-# Stage 4: Build BusyBox
+# Stage: busybox-builder
 # -----------------------------------------------------------------------------
 FROM builder-base AS busybox-builder
 
 ARG BUILD_JOBS
+ARG BUSYBOX_VERSION=master
 
-# Copy BusyBox source from downloader stage
 COPY --from=source-downloader /build/sources/busybox /build/busybox
-
-# Copy BusyBox configuration
 COPY busybox.config /build/busybox/.config
 
-# Build and install BusyBox
 WORKDIR /build/busybox
-RUN make oldconfig && \
-    make -j"${BUILD_JOBS:-$(nproc)}" && \
-    make CONFIG_PREFIX=/build/initramfs install && \
-    strip /build/initramfs/bin/busybox
+
+# Use a robust config, build, install; create an explicit tarball artifact and verify it
+SHELL ["/bin/bash", "-o", "pipefail", "-c"]
+RUN set -eux; \
+    mkdir -p /build/initramfs; \
+    # configure (prefer existing .config, accept defaults non-interactively)
+    if [ -f .config ]; then \
+      if ! yes "" | make oldconfig; then \
+        make defconfig; \
+      fi; \
+    else \
+      make defconfig; \
+    fi; \
+    # build
+    make -j"${BUILD_JOBS:-$(nproc)}"; \
+    # install into explicit path
+    make CONFIG_PREFIX=/build/initramfs install; \
+    # sanity checks — fail early with diagnostics if artifacts missing
+    if [ ! -x /build/initramfs/bin/busybox ]; then \
+      echo "ERROR: busybox install did not produce /build/initramfs/bin/busybox"; \
+      echo "workspace /build contents:"; ls -la /build || true; \
+      echo "busybox tree:"; ls -la /build/initramfs || true; \
+      exit 1; \
+    fi; \
+    # shrink binary if possible (non-fatal)
+    strip --strip-all /build/initramfs/bin/busybox || true; \
+    # create a single tarball artifact for reliable COPY by BuildKit
+    tar -C /build -czf /build/initramfs.tar.gz initramfs; \
+    ls -la /build/initramfs.tar.gz
 
 # -----------------------------------------------------------------------------
-# Stage 5: Create initramfs
+# Stage: initramfs-builder
 # -----------------------------------------------------------------------------
 FROM builder-base AS initramfs-builder
 
-# Copy BusyBox installation
-COPY --from=busybox-builder /build/initramfs /build/initramfs
+# Copy the tarball artifact and extract it, then add/overwrite init
+COPY --from=busybox-builder /build/initramfs.tar.gz /build/initramfs.tar.gz
+
+WORKDIR /build
+RUN set -eux; \
+    mkdir -p /build; \
+    tar -C /build -xzf /build/initramfs.tar.gz && rm /build/initramfs.tar.gz; \
+    ls -la /build/initramfs
 
-# Copy init script and make it executable
 COPY init.sh /build/initramfs/init
 RUN chmod +x /build/initramfs/init
 
-# Create initramfs archive
 WORKDIR /build/initramfs
 SHELL ["/bin/bash", "-o", "pipefail", "-c"]
 RUN find . -print0 | cpio --null --create --format=newc | gzip -9 > /build/initramfs.cpio.gz
 
 # -----------------------------------------------------------------------------
-# Stage 6: Create bootable ISO
+# Stage: iso-builder
 # -----------------------------------------------------------------------------
 FROM builder-base AS iso-builder
 
-# Copy syslinux files
-COPY --from=source-downloader /build/sources/syslinux /build/syslinux
+ARG SYSLINUX_VERSION=6.03
 
-# Copy kernel
+COPY --from=source-downloader /build/sources/syslinux /build/syslinux
 COPY --from=kernel-builder /build/linux/arch/x86/boot/bzImage /build/myiso/bzImage
-
-# Copy initramfs
 COPY --from=initramfs-builder /build/initramfs.cpio.gz /build/myiso/initramfs
 
-# Copy syslinux bootloader files
 WORKDIR /build
 RUN cp /build/syslinux/bios/core/isolinux.bin /build/myiso/isolinux/ && \
     cp /build/syslinux/bios/com32/elflink/ldlinux/ldlinux.c32 /build/myiso/isolinux/
 
-# Copy bootloader configuration
 COPY syslinux.cfg /build/myiso/isolinux/isolinux.cfg
 
-# Create bootable ISO
 WORKDIR /build
 RUN mkisofs \
     -J \
@@ -195,56 +213,46 @@ RUN mkisofs \
     myiso
 
 # -----------------------------------------------------------------------------
-# Stage 7: Final minimal image with artifacts
+# Stage: export-stage
 # -----------------------------------------------------------------------------
 FROM scratch AS export-stage
 
-# Copy build artifacts
 COPY --from=iso-builder /build/output.iso /output.iso
 COPY --from=kernel-builder /build/linux/arch/x86/boot/bzImage /bzImage
 COPY --from=initramfs-builder /build/initramfs.cpio.gz /initramfs
 
 # -----------------------------------------------------------------------------
-# Stage 8: Runtime image (default)
+# Stage: runtime
 # -----------------------------------------------------------------------------
 FROM debian:sid-slim AS runtime
 
-# Install only runtime dependencies
 RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
     --mount=type=cache,target=/var/lib/apt,sharing=locked \
     apt-get update && \
     apt-get install -yq --no-install-recommends \
-        qemu-system-x86 \
-        qemu-utils && \
+    qemu-system-x86 \
+    qemu-utils && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
 
-# Create non-root user for better security
 RUN groupadd -r distro && \
     useradd -r -g distro -d /distro -s /bin/bash distro && \
     mkdir -p /distro && \
     chown -R distro:distro /distro
 
-# Copy build artifacts from iso-builder stage
 COPY --from=iso-builder /build/output.iso /distro/output.iso
 COPY --from=kernel-builder /build/linux/arch/x86/boot/bzImage /distro/bzImage
 COPY --from=initramfs-builder /build/initramfs.cpio.gz /distro/initramfs
 
-# Copy scripts
 COPY --chown=distro:distro build.sh /distro/build.sh
 RUN chmod +x /distro/build.sh
 
-# Set working directory and user
 WORKDIR /distro
 USER distro
-
-# Set environment variables
 ENV DISTRO_HOME=/distro
 ENV PATH="${DISTRO_HOME}:${PATH}"
 
-# Health check
 HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
     CMD [ -f "/distro/output.iso" ] || exit 1
 
-# Default command
-CMD ["/bin/bash"]
+CMD ["/bin/bash"]

scripts/clean.sh

@@ -6,8 +6,10 @@
 
 set -euo pipefail
 
-readonly SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-readonly PROJECT_DIR="$(dirname "${SCRIPT_DIR}")"
+readonly SCRIPT_DIR
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+readonly PROJECT_DIR
+PROJECT_DIR="$(dirname "${SCRIPT_DIR}")"
 
 readonly GREEN='\033[0;32m'
 readonly BLUE='\033[0;34m'

scripts/test.sh

@@ -6,8 +6,10 @@
 
 set -euo pipefail
 
-readonly SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-readonly PROJECT_DIR="$(dirname "${SCRIPT_DIR}")"
+readonly SCRIPT_DIR
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+readonly PROJECT_DIR
+PROJECT_DIR="$(dirname "${SCRIPT_DIR}")"
 
 readonly GREEN='\033[0;32m'
 readonly RED='\033[0;31m'