feat: support links inside archives (#2436)

Signed-off-by: Carlos Alexandro Becker <caarlos0@gmail.com>

pkg/archive/targz/targz.go

@@ -43,7 +43,7 @@ func (a Archive) Add(f config.File) error {
 		return err
 	}
 	defer file.Close()
-	info, err := file.Stat()
+	info, err := os.Lstat(f.Source) // #nosec
 	if err != nil {
 		return err
 	}
@@ -66,6 +66,13 @@ func (a Archive) Add(f config.File) error {
 		header.Gid = 0
 		header.Gname = f.Info.Group
 	}
+	if info.Mode()&os.ModeSymlink != 0 {
+		target, err := os.Readlink(f.Source)
+		if err != nil {
+			return err
+		}
+		header.Linkname = target
+	}
 	if err = a.tw.WriteHeader(header); err != nil {
 		return err
 	}

pkg/archive/targz/targz_test.go

@@ -50,6 +50,14 @@ func TestTarGzFile(t *testing.T) {
 		Source:      "../testdata/sub1/sub2/subfoo.txt",
 		Destination: "sub1/sub2/subfoo.txt",
 	}))
+	require.NoError(t, archive.Add(config.File{
+		Source:      "../testdata/regular.txt",
+		Destination: "regular.txt",
+	}))
+	require.NoError(t, archive.Add(config.File{
+		Source:      "../testdata/link.txt",
+		Destination: "link.txt",
+	}))
 
 	require.NoError(t, archive.Close())
 	require.Error(t, archive.Add(config.File{
@@ -84,6 +92,9 @@ func TestTarGzFile(t *testing.T) {
 			ex := next.FileInfo().Mode() | 0o111
 			require.Equal(t, next.FileInfo().Mode().String(), ex.String())
 		}
+		if next.Name == "link.txt" {
+			require.Equal(t, next.Linkname, "regular.txt")
+		}
 	}
 	require.Equal(t, []string{
 		"foo.txt",
@@ -92,6 +103,8 @@ func TestTarGzFile(t *testing.T) {
 		"sub1/executable",
 		"sub1/sub2",
 		"sub1/sub2/subfoo.txt",
+		"regular.txt",
+		"link.txt",
 	}, paths)
 }
 

pkg/archive/tarxz/tarxz.go

@@ -42,7 +42,7 @@ func (a Archive) Add(f config.File) error {
 		return err
 	}
 	defer file.Close()
-	info, err := file.Stat()
+	info, err := os.Lstat(f.Source) // #nosec
 	if err != nil {
 		return err
 	}
@@ -65,10 +65,17 @@ func (a Archive) Add(f config.File) error {
 		header.Gid = 0
 		header.Gname = f.Info.Group
 	}
+	if info.Mode()&os.ModeSymlink != 0 {
+		target, err := os.Readlink(f.Source)
+		if err != nil {
+			return err
+		}
+		header.Linkname = target
+	}
 	if err = a.tw.WriteHeader(header); err != nil {
 		return err
 	}
-	if info.IsDir() {
+	if info.IsDir() || info.Mode()&os.ModeSymlink != 0 {
 		return nil
 	}
 	_, err = io.Copy(a.tw, file)

pkg/archive/tarxz/tarxz_test.go

@@ -50,6 +50,14 @@ func TestTarXzFile(t *testing.T) {
 		Source:      "../testdata/sub1/sub2/subfoo.txt",
 		Destination: "sub1/sub2/subfoo.txt",
 	}))
+	require.NoError(t, archive.Add(config.File{
+		Source:      "../testdata/regular.txt",
+		Destination: "regular.txt",
+	}))
+	require.NoError(t, archive.Add(config.File{
+		Source:      "../testdata/link.txt",
+		Destination: "link.txt",
+	}))
 
 	require.NoError(t, archive.Close())
 	require.Error(t, archive.Add(config.File{
@@ -83,6 +91,9 @@ func TestTarXzFile(t *testing.T) {
 			ex := next.FileInfo().Mode() | 0o111
 			require.Equal(t, next.FileInfo().Mode().String(), ex.String())
 		}
+		if next.Name == "link.txt" {
+			require.Equal(t, next.Linkname, "regular.txt")
+		}
 	}
 	require.Equal(t, []string{
 		"foo.txt",
@@ -91,6 +102,8 @@ func TestTarXzFile(t *testing.T) {
 		"sub1/executable",
 		"sub1/sub2",
 		"sub1/sub2/subfoo.txt",
+		"regular.txt",
+		"link.txt",
 	}, paths)
 }
 

pkg/archive/testdata/link.txt

@@ -0,0 +1 @@
+regular.txt

pkg/archive/zip/zip.go

@@ -39,7 +39,7 @@ func (a Archive) Add(f config.File) error {
 		return err
 	}
 	defer file.Close()
-	info, err := file.Stat()
+	info, err := os.Lstat(f.Source) // #nosec
 	if err != nil {
 		return err
 	}

pkg/archive/zip/zip_test.go

@@ -48,6 +48,14 @@ func TestZipFile(t *testing.T) {
 		Source:      "../testdata/sub1/sub2/subfoo.txt",
 		Destination: "sub1/sub2/subfoo.txt",
 	}))
+	require.NoError(t, archive.Add(config.File{
+		Source:      "../testdata/regular.txt",
+		Destination: "regular.txt",
+	}))
+	require.NoError(t, archive.Add(config.File{
+		Source:      "../testdata/link.txt",
+		Destination: "link.txt",
+	}))
 
 	require.NoError(t, archive.Close())
 	require.Error(t, archive.Add(config.File{
@@ -75,12 +83,17 @@ func TestZipFile(t *testing.T) {
 			ex := zf.Mode() | 0o111
 			require.Equal(t, zf.Mode().String(), ex.String())
 		}
+		if zf.Name == "link.txt" {
+			require.True(t, zf.FileInfo().Mode()&os.ModeSymlink != 0)
+		}
 	}
 	require.Equal(t, []string{
 		"foo.txt",
 		"sub1/bar.txt",
 		"sub1/executable",
 		"sub1/sub2/subfoo.txt",
+		"regular.txt",
+		"link.txt",
 	}, paths)
 }