--- /dev/null
+#!/bin/bash
+#
+# A script to prepare the tiniest "linux system". It's a kernel and an
+# initrd within a FAT with a syslinux boot loader. The initrd contains
+# a fully expanded busybox and uses /bin/sh as its init.
+#
+# This script creates and packs that initrd, as well as the whole,
+# boot image.
+
+set -e
+
+### Step 1. Download original .deb file from the source
+REPO="deb.devuan.org/merged"
+SUITE="daedalus"
+SECTION="main"
+ARCH="amd64"
+
+PKGFILE=${REPO//\//_}_${SUITE}_${SECTION}_binary-${ARCH}_Packages
+if [ ! -r $PKGFILE ] ; then
+ wget -O - http://$REPO/dists/$SUITE/$SECTION/binary-$ARCH/Packages.xz | \
+ xzcat - > ${PKGFILE}
+fi
+
+# Reduce that Packages file into two maps for finding filename and depends
+echo "# Creating mapdepends.txt and mapfile.txt"
+awk '
+BEGIN { print "###" > "mapdepends.txt"; print "###" > "mapfile.txt"; }
+$1=="Package:" {P=$2; next}
+$1=="Depends:" {print P,$2 >> "mapdepends.txt";next }
+$1=="Filename:" {print P,$2 >> "mapfile.txt";next }
+' ${PKGFILE}
+
+# Function to find the filename (or an map file) for a given package
+maplookup() {
+ awk -v P="$1" '$1==P {$1="" ;print; exit}' ${2-mapfile.txt} | \
+ sed 's/ //'
+}
+
+# Function to download a deb file and return its name
+debfile() {
+ local F="$(maplookup $1 mapfile.txt)"
+ if [ ! -e "${F##*/}" ] ; then
+ wget "http://$REPO/$F" || return 1
+ fi
+ echo "${F##*/}"
+}
+
+# Function to extract from a deb without executing and pre/post scripts
+# $1 = rootfs $2 = package
+debextract() {
+ ar p $2 data.tar.xz | tar xJf - -C $1
+}
+
+# Deteremine which kernel to use; this is
+echo -n "# Determining kernel: "
+KERNEL="$(maplookup linux-image-amd64 mapdepends.txt | \
+ sed 's/.*\(linux-image[^ ]*\).*/\1/')"
+echo $KERNEL
+
+### Step 2. Create and populate the initrd, and packit up.
+# The initrd contains only a few kernel modules for coping with a
+# later pivoting onto a "full" filesystem.
+
+echo "# Create initrd filesystem"
+rm -r initrd
+
+echo "# Install busybox, and fluff it up"
+fakechroot fakeroot \
+dpkg --log=dpkg.log --root=initrd -i $(debfile busybox-static)
+for L in $(initrd/bin/busybox --listfull) ; do
+ mkdir -p $(dirname initrd/$L)
+ case "$L" in
+ bin/busybox) : ;;
+ usr/*) ln -s ../../bin/busybox initrd/$L ;;
+ sbin/*) ln -s ../bin/busybox initrd/$L ;;
+ bin/*) ln -s busybox initrd/$L ;;
+ linuxrc) ln -s bin/busybox initrd/$L ;;
+ esac
+done
+
+echo "# Extract the kernel package ($KERNEL)"
+echo "# .. and syslinux stuff if needed"
+if [ ! -d kernel ] ; then
+ mkdir kernel
+ debextract kernel $(debfile $KERNEL)
+ debextract kernel $(debfile syslinux)
+ debextract kernel $(debfile syslinux-common)
+ debextract kernel $(debfile syslinux-efi)
+ debextract kernel $(debfile syslinux-utils)
+fi
+
+echo "# Include some kernel modules in the initrd"
+MODULES=(
+ # disk
+ scsi_common scsi_mod libata ata_piix ata_generic cdrom sr_mod
+ crc32-pclmul crct10dif_common crc-t10dif crc64 crc64-rocksoft
+ t10-pi sd_mod sg nls_cp437 nls_ascii fat vfat ext4 isofs
+ # input
+ psmouse evdev
+ # network
+ e1000
+)
+MOODLES=""
+B=$(pwd)
+for m in ${MODULES[@]} ; do
+ km=$(find kernel/lib/modules -name $m.ko)
+ if [ -z "$km" ] ; then
+ echo "Missing module $m"
+ continue
+ fi
+ im=initrd/${km#kernel/}
+ MOODLES+=" $B/$im"
+ mkdir -p $(dirname $im)
+ cp -n $km $im
+done
+V=${KERNEL#linux-image-}
+mkdir -p initrd/boot initrd/lib/modules/$V
+cp kernel/boot/System.map-$V initrd/
+cp kernel/lib/modules/$V/modules.order initrd/lib/modules/$V/
+cp kernel/lib/modules/$V/modules.builtin initrd/lib/modules/$V/
+depmod -F initrd/System.map-$V -b initrd $V $MOODLES
+
+echo "# setup a scripted init. The kernel runs this via the #! interpreter"
+rm -f initrd/sbin/init # just in case
+cat <<EOF > initrd/init
+#!/bin/sh
+echo
+echo
+echo "Hi there, tiniest lover!"
+
+mkdir /proc
+mount -t proc proc /proc
+mount -t devtmpfs devtmpfs /dev
+mkdir /dev/pts
+mount -t devpts devpts /dev/pts
+mkdir /sys
+mount -t sysfs sysfs /sys
+$(for m in ${MODULES[@]} ; do echo modprobe $m ; done)
+exec /bin/sh
+EOF
+chmod a+x initrd/init
+
+echo "# Now pack up that initrd as initrd.gz"
+( cd initrd ; find . | fakeroot cpio -H newc -o | gzip ) >initrd.gz
+
+### Step 3. create a 32 Mb fat filesystem with bios and UEFI boot
+rm -f bootimage.raw
+dd if=/dev/zero of=bootimage.raw bs=32M count=1
+
+# Prepare a dos partition table with a first partition marked as EFI
+sfdisk bootimage.raw <<EOF
+2048 32767 U *
+- - L
+EOF
+
+# Add a fat filesystem at 2048 61440
+mkfs.fat -n TINIEST --offset 2048 -F 16 bootimage.raw
+IMG="-i bootimage.raw@@$((2048*512))"
+
+# Add an ext2 filesystem at offset 61440*512
+# Copy initrd.gz and kernel into the fat filesystem root
+mke2fs -E offset=$((61440*512)) -F bootimage.raw
+
+mcopy $IMG initrd.gz ::
+mcopy $IMG kernel/boot/vm* ::/vmlinuz
+mcopy $IMG bootmenu.cfg ::/
+mcopy $IMG splash.png ::/
+
+echo "# Set up legacy boot"
+cat <<EOF > syslinux-legacy.cfg
+path /boot/syslinux/bios
+include /bootmenu.cfg
+EOF
+
+mmd $IMG ::/boot
+mmd $IMG ::/boot/syslinux
+mmd $IMG ::/boot/syslinux/bios
+mcopy $IMG \
+ kernel/usr/lib/syslinux/modules/bios/* ::/boot/syslinux/bios
+mcopy $IMG syslinux-legacy.cfg ::/syslinux.cfg
+
+echo "# Set up UEFI boot"
+cat <<EOF > syslinux-uefi.cfg
+path /EFI/BOOT/efi64
+include /bootmenu.cfg
+EOF
+
+mmd $IMG ::/EFI
+mmd $IMG ::/EFI/BOOT
+mmd $IMG ::/EFI/BOOT/efi64
+mcopy $IMG kernel/usr/lib/SYSLINUX.EFI/efi64/syslinux.efi \
+ ::/EFI/BOOT/bootx64.efi
+mcopy $IMG \
+ kernel/usr/lib/syslinux/modules/efi64/* ::/EFI/BOOT
+mcopy $IMG syslinux-uefi.cfg ::/EFI/BOOT/syslx64.cfg
+
+syslinux --install --offset=${IMG#*@@} bootimage.raw
+dd conv=notrunc of=bootimage.raw bs=440 count=1 \
+ if=kernel/usr/lib/syslinux/mbr/mbr.bin
+
+exit
projects / rrq / tiniest.git / commitdiff
