feat: extract bins

cmd/chisel/cmd_debug_check_release_archives.go

@@ -150,7 +150,7 @@ func computePathObservations(release *setup.Release, archives map[string]archive
 			if err != nil {
 				return nil, err
 			}
-			dataReader, err := deb.DataReader(pkgReader)
+			dataReader, err := deb.OpenTar(pkgReader)
 			if err != nil {
 				return nil, err
 			}

internal/archive/archive_test.go

@@ -20,6 +20,7 @@ import (
 
 	"github.com/canonical/chisel/internal/archive"
 	"github.com/canonical/chisel/internal/archive/testarchive"
+	"github.com/canonical/chisel/internal/deb"
 	"github.com/canonical/chisel/internal/tarball"
 	"github.com/canonical/chisel/internal/testutil"
 )
@@ -1235,7 +1236,7 @@ func (s *S) testOpenArchiveArch(c *C, test realArchiveTest, arch string) {
 	c.Assert(info.Name, DeepEquals, test.pkg)
 	c.Assert(info.Arch, DeepEquals, arch)
 
-	err = tarball.Extract(pkg, &tarball.ExtractOptions{
+	err = tarball.Extract(pkg, deb.OpenTar, &tarball.ExtractOptions{
 		Package:   test.pkg,
 		TargetDir: extractDir,
 		Extract: map[string][]tarball.ExtractInfo{

internal/deb/extract.go

@@ -10,9 +10,9 @@ import (
 	"github.com/ulikunitz/xz"
 )
 
-// DataReader takes a Reader for the ar file belonging to a Debian package and
-// returns a Reader to the inner tarball.
-func DataReader(pkgReader io.ReadSeeker) (io.ReadCloser, error) {
+// OpenTar takes a Reader for the ar file belonging to a Debian package and
+// returns a Reader to the uncompressed inner tarball.
+func OpenTar(pkgReader io.Reader) (io.ReadCloser, error) {
 	arReader := ar.NewReader(pkgReader)
 	var dataReader io.ReadCloser
 	for dataReader == nil {

internal/slicer/slicer.go

@@ -16,6 +16,7 @@ import (
 	"github.com/klauspost/compress/zstd"
 
 	"github.com/canonical/chisel/internal/archive"
+	"github.com/canonical/chisel/internal/deb"
 	"github.com/canonical/chisel/internal/fsutil"
 	"github.com/canonical/chisel/internal/manifestutil"
 	"github.com/canonical/chisel/internal/scripts"
@@ -239,7 +240,7 @@ func Run(options *RunOptions) error {
 		if reader == nil {
 			continue
 		}
-		err := tarball.Extract(reader, &tarball.ExtractOptions{
+		err := tarball.Extract(reader, deb.OpenTar, &tarball.ExtractOptions{
 			Package:   slice.Package,
 			Extract:   extract[slice.Package],
 			TargetDir: targetDir,

internal/tarball/extract.go

@@ -12,11 +12,25 @@ import (
 	"strings"
 	"syscall"
 
-	"github.com/canonical/chisel/internal/deb"
+	"github.com/ulikunitz/xz"
+
 	"github.com/canonical/chisel/internal/fsutil"
 	"github.com/canonical/chisel/internal/strdist"
 )
 
+// TarOpener returns a reader over the uncompressed tar stream contained in
+// its input, hiding the container and compression details from Extract.
+type TarOpener func(pkgReader io.Reader) (io.ReadCloser, error)
+
+// OpenXZTar returns a reader over the decompressed XZ stream.
+func OpenXZTar(pkgReader io.Reader) (io.ReadCloser, error) {
+	xzReader, err := xz.NewReader(pkgReader)
+	if err != nil {
+		return nil, err
+	}
+	return io.NopCloser(xzReader), nil
+}
+
 type ExtractOptions struct {
 	Package   string
 	TargetDir string
@@ -58,7 +72,7 @@ func getValidOptions(options *ExtractOptions) (*ExtractOptions, error) {
 	return options, nil
 }
 
-func Extract(pkgReader io.ReadSeeker, options *ExtractOptions) (err error) {
+func Extract(pkgReader io.ReadSeeker, opener TarOpener, options *ExtractOptions) (err error) {
 	defer func() {
 		if err != nil {
 			err = fmt.Errorf("cannot extract from package %q: %w", options.Package, err)
@@ -67,6 +81,10 @@ func Extract(pkgReader io.ReadSeeker, options *ExtractOptions) (err error) {
 
 	logf("Extracting files from package %q...", options.Package)
 
+	if opener == nil {
+		return fmt.Errorf("internal error: no tar opener provided")
+	}
+
 	validOpts, err := getValidOptions(options)
 	if err != nil {
 		return err
@@ -79,11 +97,11 @@ func Extract(pkgReader io.ReadSeeker, options *ExtractOptions) (err error) {
 		return err
 	}
 
-	return extractData(pkgReader, validOpts)
+	return extractData(pkgReader, opener, validOpts)
 }
 
-func extractData(pkgReader io.ReadSeeker, options *ExtractOptions) error {
-	dataReader, err := deb.DataReader(pkgReader)
+func extractData(pkgReader io.ReadSeeker, opener TarOpener, options *ExtractOptions) error {
+	dataReader, err := opener(pkgReader)
 	if err != nil {
 		return err
 	}
@@ -117,8 +135,8 @@ func extractData(pkgReader io.ReadSeeker, options *ExtractOptions) error {
 	// create them with the permissions defined in the tarball.
 	//
 	// The assumption is that the tar entries of the parent directories appear
-	// before the entry for the file itself. This is the case for .deb files but
-	// not for all tarballs.
+	// before the entry for the file itself. This is the case for the tarballs
+	// produced by common packaging tools but not for all tarballs.
 	tarDirMode := make(map[string]fs.FileMode)
 	tarReader := tar.NewReader(dataReader)
 	for {
@@ -265,7 +283,7 @@ func extractData(pkgReader io.ReadSeeker, options *ExtractOptions) error {
 		if err != nil {
 			return err
 		}
-		err = extractHardLinks(pkgReader, extractHardLinkOptions)
+		err = extractHardLinks(pkgReader, opener, extractHardLinkOptions)
 		if err != nil {
 			return err
 		}
@@ -299,8 +317,8 @@ type extractHardLinkOptions struct {
 
 // extractHardLinks iterates through the tarball a second time to extract the
 // hard links that were not extracted in the first pass.
-func extractHardLinks(pkgReader io.ReadSeeker, opts *extractHardLinkOptions) error {
-	dataReader, err := deb.DataReader(pkgReader)
+func extractHardLinks(pkgReader io.ReadSeeker, opener TarOpener, opts *extractHardLinkOptions) error {
+	dataReader, err := opener(pkgReader)
 	if err != nil {
 		return err
 	}

internal/tarball/extract_test.go

@@ -10,6 +10,7 @@ import (
 
 	. "gopkg.in/check.v1"
 
+	"github.com/canonical/chisel/internal/deb"
 	"github.com/canonical/chisel/internal/fsutil"
 	"github.com/canonical/chisel/internal/tarball"
 	"github.com/canonical/chisel/internal/testutil"
@@ -18,6 +19,7 @@ import (
 type extractTest struct {
 	summary string
 	pkgdata []byte
+	openTar tarball.TarOpener
 	options tarball.ExtractOptions
 	hackopt func(c *C, o *tarball.ExtractOptions)
 	result  map[string]string
@@ -511,7 +513,11 @@ func (s *S) TestExtract(c *C) {
 			test.hackopt(c, &options)
 		}
 
-		err := tarball.Extract(bytes.NewReader(test.pkgdata), &options)
+		openTar := test.openTar
+		if openTar == nil {
+			openTar = deb.OpenTar
+		}
+		err := tarball.Extract(bytes.NewReader(test.pkgdata), openTar, &options)
 		if test.error != "" {
 			c.Assert(err, ErrorMatches, test.error)
 			continue
@@ -539,6 +545,7 @@ func (s *S) TestExtract(c *C) {
 var extractCreateCallbackTests = []struct {
 	summary string
 	pkgdata []byte
+	openTar tarball.TarOpener
 	options tarball.ExtractOptions
 	calls   map[string][]tarball.ExtractInfo
 }{{
@@ -622,9 +629,25 @@ func (s *S) TestExtractCreateCallback(c *C) {
 			return nil
 		}
 
-		err := tarball.Extract(bytes.NewReader(test.pkgdata), &options)
+		openTar := test.openTar
+		if openTar == nil {
+			openTar = deb.OpenTar
+		}
+		err := tarball.Extract(bytes.NewReader(test.pkgdata), openTar, &options)
 		c.Assert(err, IsNil)
 
 		c.Assert(createExtractInfos, DeepEquals, test.calls)
 	}
 }
+
+func (s *S) TestExtractMissingOpenTar(c *C) {
+	options := tarball.ExtractOptions{
+		Package:   "test-package",
+		TargetDir: c.MkDir(),
+		Extract: map[string][]tarball.ExtractInfo{
+			"/dir/file": {{Path: "/dir/file"}},
+		},
+	}
+	err := tarball.Extract(bytes.NewReader(testutil.PackageData["test-package"]), nil, &options)
+	c.Assert(err, ErrorMatches, `cannot extract from package "test-package": internal error: no tar opener provided`)
+}