Downloading syslinux files on build

Dockerfile

@@ -3,25 +3,43 @@ FROM debian:buster
 RUN apt update
 RUN apt install -y make debootstrap supervisor isc-dhcp-server tftpd-hpa busybox squashfs-tools
 
-# Linux image
+# Downloads base Debian 10 to /linux/build/cache. The Makefile in linux/ would
+# download base debian system to linux/build/cache itself, but to speed up
+# rebuilding this Docker container the download is run separately to avoid
+# repeating it in future builds.
 ADD linux /linux
 RUN mkdir -p linux/build && debootstrap buster linux/build/cache
-RUN cd /linux && make
 
-# Files to be served
+# Copies src/tftpboot directory to /tftpboot
 ADD src/tftpboot /tftpboot
+
+# Downloads Syslinux and moves ldlinux.c32 and pxelinux.0 files to /tftpboot
+RUN wget https://mirrors.edge.kernel.org/pub/linux/utils/boot/syslinux/syslinux-6.03.tar.gz && \
+	tar -xzvf syslinux-6.03.tar.gz && \
+	cp syslinux-6.03/bios/core/pxelinux.0 /tftpboot/pxelinux.0 && \
+	cp syslinux-6.03/bios/com32/elflink/ldlinux/ldlinux.c32 /tftpboot/ldlinux.c32
+
+# Builds Linux with its Makefile
+RUN cd /linux && make
+
+# Creates and populates /tftpboot directory. Files stored there will be served
+# by TFTP and HTTP (on port 8014).
 RUN cp /linux/build/rootfs/initrd.img /tftpboot/initrd.img && \
 	cp /linux/build/rootfs/vmlinuz /tftpboot/vmlinuz && \
 	mksquashfs /linux/build/rootfs /tftpboot/root.squashfs
 
-# Supervisor
+# Supervisor's config
 COPY src/supervisor.conf /supervisor.conf
 
-# DHCP server
+# DHCP server config
 RUN mkdir -p /var/lib/dhcp && touch /var/lib/dhcp/dhcpd.leases
 COPY src/dhcpd.conf /etc/dhcp/dhcpd.conf
 
+# The run.sh script setups networking and starts supervisor.
 COPY src/run.sh /run.sh
 RUN chmod +x /run.sh
+
+# Interface on which the server will be listening. Set with `-e INTERFACE=eth1`
 ENV INTERFACE=eth0
+
 CMD ["/run.sh"]

Readme.md

@@ -36,7 +36,7 @@ An example run command might look like this:
 docker run -e INETRFACE=eth42 --privileged --net host hugo/images
 ```
 
-After starting the server, all PCs connected to the network, when in network boot mode, should boot linux for cloning and present the user with a menu.
+After starting the server, all PCs connected to the network, when in network boot mode, should boot specialised Linux for cloning and present the user with a menu.
 
 ## Technical details
 
@@ -60,9 +60,9 @@ The boot process of a computer connected to the server consists of the following
 
 ### Linux
 
-The Linux system served boots to a menu allowing to send/receive:
+The Linux system being server is based on minimal Debian 10 Buster and boots to a menu allowing to send/receive:
 1. MBR of `/dev/sda` (raw copy of first 512 bytes, made by `dd`)
-2. Partition table (in `sfdisk`'s format)
+2. Partition table (in `sfdisk` format)
 3. Image of `/dev/sda1` partition (in `partimage` format)
 
 Both sending and receiving is done with UDP broadcast with `udpsender`/`udpreceiver`. Any custom action can be performed with root shell. See `linux/scripts` for more details.

scripts/receive.sh

@@ -1,4 +0,0 @@
-#!/bin/bash
-
-INTERFACE=$1
-udp-receiver --interface $INTERFACE

scripts/send.sh

@@ -1,4 +0,0 @@
-#!/bin/bash
-
-INTERFACE=$1
-udp-sender --interface $INTERFACE