mediagen

#!/usr/bin/env bash
#
# Copyright (C) 2018 Christopher Obbard <chris@64studio.com>
#
#

# command-line arguments
PDK_WORKSPACE="$1"
PDK_COMPONENT="$2"

# full path to the component meta xml file
PDK_COMPONENT_FILE="$PDK_WORKSPACE/$PDK_COMPONENT"

# full path to the apt repo
PDK_REPO="$PDK_WORKSPACE/repo"

# full path to build env
BUILDENV="$PDK_WORKSPACE/tmp"

# temp image file
IMAGE="$BUILDENV/tmp.img"

# full path to the rootfs
ROOTFS="$BUILDENV/rootfs"

# full path to the mediagen script
SCRIPTPATH="$(cd "$(dirname "$0")"; pwd -P)"

# include mediagen functions
. $SCRIPTPATH/functions.sh

# check root is running the script
if [ $EUID -ne 0 ]; then
  error "you must run as root"
  exit 1
fi

# check workspace exists
if [ ! -d $PDK_WORKSPACE ]; then
  error "cannot find PDK workspace"
  exit 1
fi

# check component file exists
if [ ! -f $PDK_COMPONENT_FILE ]; then
  error "cannot find PDK component"
  exit 1
fi

# check repo has been created
if [ ! -d $PDK_REPO ]; then
  error "cannot find repo! please run repogen first"
  exit 1
fi

# get configuration options
# TODO: sanitize options better
RECIPE=$(read_meta "mediagen.recipe")
if [ -z "$RECIPE" ]; then
  error "mediagen.recipe not found"
  exit 1
fi

ARCH=$(read_meta "mediagen.debarch")
if [ -z "$ARCH" ]; then
  error "mediagen.debarch not found"
  exit 1
fi

ROOTSIZE=$(read_meta "mediagen.rootsize")
if [ -z "$ROOTSIZE" ]; then
  error "mediagen.rootsize not found"
  exit 1
fi

BOOTSIZE=$(read_meta "mediagen.bootsize")
if [ -z "$BOOTSIZE" ]; then
  error "mediagen.bootsize not found"
  exit 1
fi

OUTFILE=$(read_meta "mediagen.outfile")
if [ -z "$OUTFILE" ]; then
  error "mediagen.outfile not found"
  exit 1
fi

# TODO: move these config options elsewhere?
HOSTNAME=$(read_meta "mediagen.hostname")
if [ -z "$HOSTNAME" ]; then
  info "mediagen.hostname not found; defaulting to 'pdk'"
  HOSTNAME="pdk"
fi

ROOT_PASSWORD=$(read_meta "mediagen.root-password")
if [ -z "$ROOT_PASSWORD" ]; then
  info "mediagen.root-password not found; defaulting to 'toor'"
  ROOT_PASSWORD="toor"
fi

PRESEED=$(read_meta "mediagen.preseed-conf")
if [ -z "$PRESEED" ]; then
  info "mediagen.preseed-conf not found; no preseed file selected"
fi

POSTINST=$(read_meta "mediagen.postinst-script")
if [ -z "$POSTINST" ]; then
  info "mediagen.postinst-script not found; no postinst script selected"
fi

REPO_URL=$(read_meta "mediagen.repo-url")
if [ -z "$REPO_URL" ]; then
  info "mediagen.repo-url not found; set this to the apt repository url to use in target installation"
fi


# get the codename
# TODO: read codename directly from pdk
CODENAME=$(ls "$PDK_REPO/dists" | head -1)
if [ -z "$CODENAME" ]; then
  error "codename not found"
  exit 1
fi


# purge old build env
rm -rf $IMAGE
rm -rf $BUILDENV
mkdir -p $BUILDENV

# create blank image $ROOTSIZE blocks long
info "creating blank image"
dd if=/dev/zero of=$IMAGE bs=1MiB count=$ROOTSIZE >& /dev/null

# create partition table
#
#  first 2kb bootloader & partition table,
#  next ${BOOTSIZE} mb FAT32,
#  rest of disk rootfs
info "creating filesystems"
fdisk $IMAGE &>/dev/null << EOF
n
p
1
2048
+${BOOTSIZE}M
t
c
a
1
n
p
2


w
EOF

# create device map
info "creating loop device"
DEVICE=`kpartx -a -v $IMAGE | sed -E 's/.*(loop[0-9])p.*/\1/g' | head -1`
sleep 1

DEVICE_BOOTFS="/dev/mapper/${DEVICE}p1"
DEVICE_ROOTFS="/dev/mapper/${DEVICE}p2"
info "created loop device $DEVICE"

# format
info "formatting filesystems"
mkfs.vfat $DEVICE_BOOTFS >& /dev/null
mkfs.ext4 $DEVICE_ROOTFS >& /dev/null

# mount
info "mounting rootfs"
mkdir -p $ROOTFS
mount $DEVICE_ROOTFS $ROOTFS

mkdir -p ${ROOTFS}/boot
mount $DEVICE_BOOTFS ${ROOTFS}/boot

# do evil things to the rootfs here

# loop over all of the scripts
for SHELL_SCRIPT in $SCRIPTPATH/scripts/*.sh; do
  # get the name of the script without the full path
  SHELL_SCRIPT_NAME=$(echo $SHELL_SCRIPT | rev | cut -d "/" -f1 | rev)

  # run it!
  info "Running $SHELL_SCRIPT_NAME"
  . "$SHELL_SCRIPT"
done

# stop the doing evil things to the rootfs here

# unmount
info "cleaning up"
info "unmounting rootfs"
cd $SCRIPTPATH
sleep 2
umount $DEVICE_BOOTFS
umount $DEVICE_ROOTFS

# remove the device maps
info "removing loop devices"
kpartx -d $IMAGE >& /dev/null
sleep 2

# move the image from the tmp dir to the workspace
# TODO: don't do this if it has failed
OUTFILE="$PDK_WORKSPACE/$OUTFILE"
rm -rf "$OUTFILE"
mv "$IMAGE" "$OUTFILE"
chown --reference="$PDK_COMPONENT_FILE" "$OUTFILE"

# remove the tmp dir
rm -rf $BUILDENV

# exit
info "completed!"
exit 0