unpacker.eclass: Add on-the-fly .gpkg.tar unpacking support

Signed-off-by: Michał Górny <[email protected]>

eclass/tests/unpacker.sh

@@ -136,6 +136,43 @@ test_deb() {
 		"create_deb '${suffix}' '${tool_cmd}' \${archive} \${TESTFILE}"
 }
 
+create_gpkg() {
+	local suffix=${1}
+	local tool=${2}
+	local archive=${3}
+	local infile=${4}
+	local gpkg_dir=${archive%.gpkg.tar}
+
+	mkdir image metadata "${gpkg_dir}" || die
+	cp "${infile}" image/ || die
+	tar -c metadata | ${tool} > "${gpkg_dir}/metadata.tar${suffix}"
+	assert "packing metadata.tar${suffix} failed"
+	: > "${gpkg_dir}/metadata.tar${suffix}.sig" || die
+	tar -c image | ${tool} > "${gpkg_dir}/image.tar${suffix}"
+	assert "packing image.tar${suffix} failed"
+	: > "${gpkg_dir}/image.tar${suffix}.sig" || die
+	: > "${gpkg_dir}"/gpkg-1 || die
+	tar -cf "${archive}" --format=ustar \
+		"${gpkg_dir}"/{gpkg-1,{metadata,image}.tar"${suffix}"} || die
+	rm -r image metadata "${gpkg_dir}" || die
+}
+
+test_gpkg() {
+	local suffix=${1}
+	local tool=${2}
+	local tool_cmd
+
+	if [[ -n ${tool} ]]; then
+		tool_cmd="${tool} -c"
+	else
+		tool_cmd=cat
+	fi
+
+	test_unpack "test-${tool}-1.2.3-1.gpkg.tar" \
+		"test-${tool}-1.2.3-1/image/test.in" "tar ${tool}" \
+		"create_gpkg '${suffix}' '${tool_cmd}' \${archive} \${TESTFILE}"
+}
+
 test_reject_junk() {
 	local suffix=${1}
 	local archive=test${1}
@@ -209,6 +246,16 @@ test_deb .xz xz
 test_deb .bz2 bzip2
 test_deb .lzma lzma
 
+test_gpkg
+test_gpkg .gz gzip
+test_gpkg .bz2 bzip2
+test_gpkg .lz4 lz4
+test_gpkg .lz lzip
+test_gpkg .lzma lzma
+test_gpkg .lzo lzop
+test_gpkg .xz xz
+test_gpkg .zst zstd
+
 test_unpack test.zip test.in zip 'zip -q ${archive} ${TESTFILE}'
 # test handling non-adjusted zip with junk prepended
 test_unpack test.zip test.in zip \

eclass/unpacker.eclass

@@ -408,6 +408,42 @@ _unpacker_get_decompressor() {
 	esac
 }
 
+# @FUNCTION: unpack_gpkg
+# @USAGE: <gpkg file>
+# @DESCRIPTION:
+# Unpack the image subarchive of a GPKG package on-the-fly, preserving
+# the original directory structure (i.e. into <gpkg-dir>/image).
+unpack_gpkg() {
+	[[ $# -eq 1 ]] || die "Usage: ${FUNCNAME} <file>"
+
+	local gpkg=$(find_unpackable_file "$1")
+	unpack_banner "${gpkg}"
+
+	local l images=()
+	while read -r l; do
+		case ${l} in
+			*/image.tar*.sig)
+				;;
+			*/image.tar*)
+				images+=( "${l}" )
+				;;
+		esac
+	done < <(tar -tf "${gpkg}" || die "unable to list ${gpkg}")
+
+	if [[ ${#images[@]} -eq 0 ]]; then
+		die "No image.tar found in ${gpkg}"
+	elif [[ ${#images[@]} -gt 1 ]]; then
+		die "More than one image.tar found in ${gpkg}"
+	fi
+
+	local decomp=$(_unpacker_get_decompressor "${images[0]}")
+	local dirname=${images[0]%/*}
+	mkdir -p "${dirname}" || die
+	tar -xOf "${gpkg}" "${images[0]}" | ${decomp:-cat} |
+		tar --no-same-owner -xC "${dirname}"
+	assert "Unpacking ${gpkg} failed"
+}
+
 # @FUNCTION: _unpacker
 # @USAGE: <one archive to unpack>
 # @INTERNAL
@@ -427,6 +463,8 @@ _unpacker() {
 	# then figure out if there are any archiving aspects
 	local arch=""
 	case ${m} in
+	*.gpkg.tar)
+		arch="unpack_gpkg" ;;
 	*.tgz|*.tbz|*.tbz2|*.txz|*.tar.*|*.tar)
 		arch="tar --no-same-owner -xof" ;;
 	*.cpio.*|*.cpio)