Dockerfile.linuxbusybox

# Dockerfile for building Linux kernel and BusyBox

# Stage 1: Build the Linux kernel and BusyBox
FROM ubuntu:latest AS builder

# Install necessary build dependencies
RUN apt-get update && apt-get install -y \
    wget \
    build-essential \
    libssl-dev \
    bc \
    flex \
    bison \
    libelf-dev \
    libncurses-dev \
    cpio

# Set the working directory
WORKDIR /build

# Check if the Linux kernel source code is already present
RUN [ -f "linux-5.14.tar.xz" ] || wget https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.14.tar.xz
RUN [ -d "linux-5.14" ] || tar -xf linux-5.14.tar.xz

# Change into the Linux kernel source code directory
WORKDIR /build/linux-5.14

# Build the kernel with tinyconfig
RUN make tinyconfig
RUN make -j$(nproc)

# Set the working directory
WORKDIR /build

# Check if the BusyBox source code is already present
RUN [ -f "busybox-1.34.1.tar.bz2" ] || wget https://busybox.net/downloads/busybox-1.34.1.tar.bz2
RUN [ -d "busybox-1.34.1" ] || tar -xf busybox-1.34.1.tar.bz2

# Change into the BusyBox source code directory
WORKDIR /build/busybox-1.34.1

# Build BusyBox with default configuration
RUN make defconfig
RUN make -j$(nproc)
RUN make install

# Stage 2: Create the bootable disk image
FROM scratch

# Set the necessary environment variables
ENV PATH="/bin"
ENV TERM="xterm"

# Copy the compiled BusyBox binaries from the builder stage
COPY --from=builder /build/busybox-1.34.1/_install/bin/busybox /bin/busybox

# Copy the compiled Linux kernel image from the builder stage
COPY --from=builder /build/linux-5.14/arch/x86/boot/bzImage /boot/vmlinuz

# Set the entrypoint to the BusyBox binary
ENTRYPOINT ["/bin/busybox"]