pelf-dwfs_extract

#!/bin/sh

set -e

# Function to display usage information
usage() {
	echo "Usage: $0 [--base64] input_file output_directory"
}

# Parse command line options
RAW_MODE=true # Default mode is now raw mode

while [ "$#" -ne 0 ]; do
	case "$1" in
	--base64)
		RAW_MODE=false # Switch to base64 mode if --base64 is specified
		;;
	*)
		break
		;;
	esac
	shift
done

# Check if the required arguments are provided
if [ $# -ne 2 ]; then
	usage
	exit 1
fi

INPUT_FILE="$1"
OUTPUT_DIR="$2"

# Create a temporary directory for the extraction process
_VAR_BUNDLE_DIR="${TMPDIR:-/tmp}/.pelf_extract"
_VAR_BWORK_DIR="${_VAR_BUNDLE_DIR}/pbundle_${INPUT_FILE##*/}_$(date '+%s%M%S')" # Temporary work directory
_VAR_ARCHIVE="$_VAR_BWORK_DIR/archive.dwfs"                                     # Path to the DwarFS archive
mkdir -p "$_VAR_BWORK_DIR"

# Cleanup function to remove the temporary directories
cleanup() {
	rm -rf "$_VAR_BUNDLE_DIR" 2>/dev/null || true
}
trap cleanup INT TERM HUP QUIT EXIT

# Find the line number where the archive starts
ARCHIVE_MARKER=$(awk '/^__ARCHIVE_MARKER__/ { print NR + 1; exit }' "$INPUT_FILE")

# Check if the archive marker was found
if [ -z "$ARCHIVE_MARKER" ]; then
	echo "Error: Archive marker not found in the input file." >&2
	exit 1
fi

# Ensure the output directory exists
mkdir -p "$OUTPUT_DIR"

# Extract the archive based on whether --base64 is used
if $RAW_MODE; then
	# Extract the archive directly (no decoding)
	tail -n +$ARCHIVE_MARKER "$INPUT_FILE" >"$_VAR_ARCHIVE" || {
		echo "Error: Failed to extract raw DwarfFS archive." >&2
		exit 1
	}
else
	# Decode the base64-encoded archive before extracting
	tail -n +$ARCHIVE_MARKER "$INPUT_FILE" | base64 -d >"$_VAR_ARCHIVE" || {
		echo "Error: Failed to decode and extract DwarFS archive." >&2
		exit 1
	}
fi

# Check if the archive was extracted and exists
if [ -f "$_VAR_ARCHIVE" ]; then
	# Try extracting the DwarFS archive using dwarfsextract
	dwarfsextract --input "$_VAR_ARCHIVE" --output "$OUTPUT_DIR" || {
		echo "Error: Failed to extract the DwarFS archive. Please check if the file is valid." >&2
		exit 1
	}
else
	echo "Error: DwarFS archive not found after extraction." >&2
	exit 1
fi

echo "Files extracted successfully to $OUTPUT_DIR"