rel2fw.sh

#!/usr/bin/env bash
set -e

PWD=${PWD:-$(pwd)}
BUILD_DIR=${MIX_BUILD_PATH:-$(pwd)/_build}
PROJECT_DIR=$(basename "$PWD")

SCRIPT_NAME=$0

# Check that we have everything that we need
[[ -z "$NERVES_SYSTEM" ]] && { echo "$SCRIPT_NAME: Source nerves-env.sh and try again."; exit 1; }

# Initialize this script's temporary directory
TMP_DIR=$BUILD_DIR/_nerves-tmp
rm -fr "$TMP_DIR"
mkdir -p "$TMP_DIR"
function cleanup {
  rm -fr "$TMP_DIR"
}
trap cleanup EXIT

usage() {
    echo "Usage: $SCRIPT_NAME [options] <Release directory>"
    echo
    echo "Options:"
    echo "  -a <path to rootfs overlay> May be supplied multiple times."
    echo "  -c <fwup.conf>             Default is $NERVES_SDK_IMAGES/fwup.conf"
    echo "  -f <firmware output file>  Default is $PROJECT_DIR.fw"
    echo "  -o <image output file>     Default is $PROJECT_DIR.img"
    echo "  -p <file priorities>       The ordering of files in the rootfs (may be specified more than once)"
    echo
    echo "Barring errors, the firmware file is always created. The raw image is only"
    echo "created if specified."
    echo

    echo "Example:"
    echo "$SCRIPT_NAME -f $PROJECT_DIR.fw -o $PROJECT_DIR.img _rel"
}

# Create a base priority file
#
# Seed it with erlinit being the highest priority since we know those
# files are guaranteed to be in the filesystem and accessed first on
# boot.
SQUASHFS_PRIORITIES="$TMP_DIR/squashfs.priority"
cat > "$SQUASHFS_PRIORITIES" <<END
sbin/init 32764
etc/erlinit.config 32763
END

while getopts "a:c:f:o:p:" opt; do
    case $opt in
        a)
            ROOTFS_OVERLAYS="$ROOTFS_OVERLAYS $OPTARG"
            ;;
        c)
            FWUP_CONFIG="$OPTARG"
            ;;
        f)
            FW_FILENAME="$OPTARG"
            ;;
        o)
            IMG_FILENAME="$OPTARG"
            ;;
        p)
            # Append priorities to the master list
            cat "$OPTARG" >> "$SQUASHFS_PRIORITIES"
            ;;
        \?)
            echo "$SCRIPT_NAME: ERROR: Invalid option: -$OPTARG"
            usage
            exit 1
            ;;
        :)
            echo "$SCRIPT_NAME: ERROR: Option -$OPTARG requires an argument."
            usage
            exit 1
            ;;
    esac
done
shift $((OPTIND-1))

if [[ $# -lt 1 ]]; then
    echo "$SCRIPT_NAME: ERROR: Expecting release directory"
    usage
    exit 1
fi

RELEASE_DIR=$1


# If the toolchain contains a pre-built version of fwup,
# use it; otherwise look for one in the path.
FWUP=$NERVES_TOOLCHAIN/usr/bin/fwup
[[ -e "$FWUP" ]] || FWUP=$(command -v fwup || echo "/usr/bin/fwup")
if [[ ! -e "$FWUP" ]]; then
    echo "$SCRIPT_NAME: ERROR: Please install fwup first"
    echo
    echo "See https://github.com/fhunleth/fwup"
    exit 1
fi

# Check that mksquashfs is in the path. It's needed by
# merge-squashfs.
MKSQUASHFS=$(command -v mksquashfs)
if [[ ! -e "$MKSQUASHFS" ]]; then
    echo "$SCRIPT_NAME: ERROR: Please install mksquashfs first"
    echo
    echo "For example:"
    echo "   sudo apt-get install squashfs-tools"
    echo "   brew install squashfs"
    exit 1
fi

# Fill in defaults
[[ -z "$FW_FILENAME" ]] && FW_FILENAME=${PROJECT_DIR}.fw
[[ -z "$FWUP_CONFIG" ]] && FWUP_CONFIG=$NERVES_SDK_IMAGES/fwup.conf

# Check that the release directory exists
if [[ ! -d "$RELEASE_DIR" ]]; then
    echo "$SCRIPT_NAME: ERROR: Missing Erlang release directory: ($RELEASE_DIR)"
    exit 1
fi
if [[ ! -d "$RELEASE_DIR/lib" || ! -d "$RELEASE_DIR/releases" ]]; then
    echo "$SCRIPT_NAME: ERROR: Expecting '$RELEASE_DIR' to contain 'lib' and 'releases' subdirectories"
    exit 1
fi

# Make sure that the firmware output directories are there.
mkdir -p "$(dirname "$FW_FILENAME")"

# Update the file system bundle
echo "Updating base firmware image with Erlang release..."

# Construct the proper path for the Erlang/OTP release
mkdir -p "$TMP_DIR/rootfs_overlay/srv/erlang"
cp -R "$RELEASE_DIR/." "$TMP_DIR/rootfs_overlay/srv/erlang"

# Clean up the Erlang release of all the files that we don't need.
"$NERVES_SYSTEM/scripts/scrub-otp-release.sh" "$TMP_DIR/rootfs_overlay/srv/erlang"

# Copy over any rootfs overlays from the user
# IMPORTANT: This must be the final step before the merge so that the user can
#            override anything.
if [[ "$ROOTFS_OVERLAYS" ]]; then
    for OVERLAY in $ROOTFS_OVERLAYS; do
      if [[ -d $OVERLAY ]]; then
          echo "Copying rootfs_overlay: $OVERLAY"
          cp -Rf "$OVERLAY/." "$TMP_DIR/rootfs_overlay"
      elif [[ -n "$OVERLAY" ]]; then
          echo "rootfs_overlay: $OVERLAY does not exist!"
          exit 1
      fi
    done
fi

# Merge the Erlang/OTP release onto the base image
"$NERVES_SYSTEM/scripts/merge-squashfs" "$NERVES_SDK_IMAGES/rootfs.squashfs" "$TMP_DIR/combined.squashfs" "$TMP_DIR/rootfs_overlay" "$SQUASHFS_PRIORITIES"

# Build the firmware image
echo "Building $FW_FILENAME..."
ROOTFS="$TMP_DIR/combined.squashfs" $FWUP -c -f "$FWUP_CONFIG" \
	-o "$FW_FILENAME"

if [[ -n "$IMG_FILENAME" ]]; then
    # Create the output directory - just in case
    mkdir -p "$(dirname "$IMG_FILENAME")"

    # Erase the image file in case it exists from a previous build.
    # We use fwup in "programming" mode to create the raw image so it expects there
    # the destination to exist (like an MMC device). This provides the minimum sized image.
    rm -f "$IMG_FILENAME"
    touch "$IMG_FILENAME"

    # Build the raw image for the bulk programmer
    echo "Building $IMG_FILENAME..."
    $FWUP -a -d "$IMG_FILENAME" -t complete -i "$FW_FILENAME"
fi