Adds sorting functionality for symlinks to ensure that symlinks of sy…

…mlinks have their base link created before themselves

vacation/init_test.go

@@ -10,6 +10,7 @@ import (
 func TestVacation(t *testing.T) {
 	suite := spec.New("vacation", spec.Report(report.Terminal{}))
 	suite("VacationArchive", testVacationArchive)
+	suite("VacationSymlinkSorting", testVacationSymlinkSorting)
 	suite("VacationTar", testVacationTar)
 	suite("VacationTarGzip", testVacationTarGzip)
 	suite("VacationTarXZ", testVacationTarXZ)

vacation/vacation.go

@@ -14,6 +14,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"sort"
 	"strings"
 
 	"github.com/gabriel-vasile/mimetype"
@@ -165,11 +166,15 @@ func (ta TarArchive) Decompress(destination string) error {
 		}
 	}
 
+	sort.Slice(symlinkHeaders, func(i, j int) bool {
+		return filepath.Clean(symlinkHeaders[i].name) < filepath.Clean(filepath.Join(filepath.Dir(symlinkHeaders[j].name), symlinkHeaders[j].linkname))
+	})
+
 	for _, h := range symlinkHeaders {
 		// Check to see if the file that will be linked to is valid for symlinking
 		_, err := filepath.EvalSymlinks(filepath.Join(filepath.Dir(h.path), h.linkname))
 		if err != nil {
-			return err
+			return fmt.Errorf("failed to evaluate symlink %s: %w", h.path, err)
 		}
 
 		// Check that the file being symlinked to is inside the destination
@@ -395,11 +400,15 @@ func (z ZipArchive) Decompress(destination string) error {
 		}
 	}
 
+	sort.Slice(symlinkHeaders, func(i, j int) bool {
+		return filepath.Clean(symlinkHeaders[i].name) < filepath.Clean(filepath.Join(filepath.Dir(symlinkHeaders[j].name), symlinkHeaders[j].linkname))
+	})
+
 	for _, h := range symlinkHeaders {
 		// Check to see if the file that will be linked to is valid for symlinking
 		_, err := filepath.EvalSymlinks(filepath.Join(filepath.Dir(h.path), h.linkname))
 		if err != nil {
-			return err
+			return fmt.Errorf("failed to evaluate symlink %s: %w", h.path, err)
 		}
 
 		// Check that the file being symlinked to is inside the destination

vacation/vacation_symlink_sorting_test.go

@@ -0,0 +1,167 @@
+package vacation_test
+
+import (
+	"archive/tar"
+	"archive/zip"
+	"bytes"
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/paketo-buildpacks/packit/vacation"
+	"github.com/sclevine/spec"
+
+	. "github.com/onsi/gomega"
+)
+
+func testVacationSymlinkSorting(t *testing.T, context spec.G, it spec.S) {
+	var (
+		Expect = NewWithT(t).Expect
+	)
+
+	context("TarArchive test that symlinks are sorted so that symlink to other symlinks are created after the initial symlink", func() {
+		var (
+			tempDir    string
+			tarArchive vacation.TarArchive
+		)
+
+		it.Before(func() {
+			var err error
+			tempDir, err = os.MkdirTemp("", "vacation")
+			Expect(err).NotTo(HaveOccurred())
+
+			buffer := bytes.NewBuffer(nil)
+			tw := tar.NewWriter(buffer)
+
+			Expect(tw.WriteHeader(&tar.Header{Name: "b-symlink", Mode: 0755, Size: int64(0), Typeflag: tar.TypeSymlink, Linkname: filepath.Join("a-symlink", "x")})).To(Succeed())
+			_, err = tw.Write([]byte{})
+			Expect(err).NotTo(HaveOccurred())
+
+			Expect(tw.WriteHeader(&tar.Header{Name: "a-symlink", Mode: 0755, Size: int64(0), Typeflag: tar.TypeSymlink, Linkname: "z"})).To(Succeed())
+			_, err = tw.Write([]byte{})
+			Expect(err).NotTo(HaveOccurred())
+
+			Expect(tw.WriteHeader(&tar.Header{Name: "z", Mode: 0755, Typeflag: tar.TypeDir})).To(Succeed())
+			_, err = tw.Write(nil)
+			Expect(err).NotTo(HaveOccurred())
+
+			xFile := filepath.Join("z", "x")
+			Expect(tw.WriteHeader(&tar.Header{Name: xFile, Mode: 0755, Size: int64(len(xFile))})).To(Succeed())
+			_, err = tw.Write([]byte(xFile))
+			Expect(err).NotTo(HaveOccurred())
+
+			Expect(tw.Close()).To(Succeed())
+
+			tarArchive = vacation.NewTarArchive(bytes.NewReader(buffer.Bytes()))
+		})
+
+		it.After(func() {
+			Expect(os.RemoveAll(tempDir)).To(Succeed())
+		})
+
+		it("unpackages the archive into the path", func() {
+			var err error
+			err = tarArchive.Decompress(tempDir)
+			Expect(err).ToNot(HaveOccurred())
+
+			files, err := filepath.Glob(fmt.Sprintf("%s/*", tempDir))
+			Expect(err).NotTo(HaveOccurred())
+			Expect(files).To(ConsistOf([]string{
+				filepath.Join(tempDir, "a-symlink"),
+				filepath.Join(tempDir, "b-symlink"),
+				filepath.Join(tempDir, "z"),
+			}))
+
+			Expect(filepath.Join(tempDir, "z")).To(BeADirectory())
+			Expect(filepath.Join(tempDir, "z", "x")).To(BeARegularFile())
+
+			link, err := os.Readlink(filepath.Join(tempDir, "a-symlink"))
+			Expect(err).NotTo(HaveOccurred())
+			Expect(link).To(Equal("z"))
+
+			data, err := os.ReadFile(filepath.Join(tempDir, "b-symlink"))
+			Expect(err).NotTo(HaveOccurred())
+			Expect(data).To(Equal([]byte(filepath.Join("z", "x"))))
+		})
+	})
+
+	context("ZipArchive test that symlinks are sorted so that symlink to other symlinks are created after the initial symlink", func() {
+		var (
+			tempDir    string
+			zipArchive vacation.ZipArchive
+		)
+
+		it.Before(func() {
+			var err error
+			tempDir, err = os.MkdirTemp("", "vacation")
+			Expect(err).NotTo(HaveOccurred())
+
+			buffer := bytes.NewBuffer(nil)
+			zw := zip.NewWriter(buffer)
+
+			fileHeader := &zip.FileHeader{Name: "b-symlink"}
+			fileHeader.SetMode(0755 | os.ModeSymlink)
+
+			bSymlink, err := zw.CreateHeader(fileHeader)
+			Expect(err).NotTo(HaveOccurred())
+
+			_, err = bSymlink.Write([]byte(filepath.Join("a-symlink", "x")))
+			Expect(err).NotTo(HaveOccurred())
+
+			fileHeader = &zip.FileHeader{Name: "a-symlink"}
+			fileHeader.SetMode(0755 | os.ModeSymlink)
+
+			aSymlink, err := zw.CreateHeader(fileHeader)
+			Expect(err).NotTo(HaveOccurred())
+
+			_, err = aSymlink.Write([]byte(`z`))
+			Expect(err).NotTo(HaveOccurred())
+
+			_, err = zw.Create("z" + string(filepath.Separator))
+			Expect(err).NotTo(HaveOccurred())
+
+			fileHeader = &zip.FileHeader{Name: filepath.Join("z", "x")}
+			fileHeader.SetMode(0644)
+
+			xFile, err := zw.CreateHeader(fileHeader)
+			Expect(err).NotTo(HaveOccurred())
+
+			_, err = xFile.Write([]byte("x file"))
+			Expect(err).NotTo(HaveOccurred())
+
+			Expect(zw.Close()).To(Succeed())
+
+			zipArchive = vacation.NewZipArchive(bytes.NewReader(buffer.Bytes()))
+		})
+
+		it.After(func() {
+			Expect(os.RemoveAll(tempDir)).To(Succeed())
+		})
+
+		it("unpackages the archive into the path", func() {
+			var err error
+			err = zipArchive.Decompress(tempDir)
+			Expect(err).ToNot(HaveOccurred())
+
+			files, err := filepath.Glob(fmt.Sprintf("%s/*", tempDir))
+			Expect(err).NotTo(HaveOccurred())
+			Expect(files).To(ConsistOf([]string{
+				filepath.Join(tempDir, "a-symlink"),
+				filepath.Join(tempDir, "b-symlink"),
+				filepath.Join(tempDir, "z"),
+			}))
+
+			Expect(filepath.Join(tempDir, "z")).To(BeADirectory())
+			Expect(filepath.Join(tempDir, "z", "x")).To(BeARegularFile())
+
+			link, err := os.Readlink(filepath.Join(tempDir, "a-symlink"))
+			Expect(err).NotTo(HaveOccurred())
+			Expect(link).To(Equal("z"))
+
+			data, err := os.ReadFile(filepath.Join(tempDir, "b-symlink"))
+			Expect(err).NotTo(HaveOccurred())
+			Expect(data).To(Equal([]byte(`x file`)))
+		})
+	})
+}

vacation/vacation_tar_test.go

@@ -255,6 +255,7 @@ func testVacationTar(t *testing.T, context spec.G, it spec.S) {
 
 				it("returns an error", func() {
 					err := zipSlipSymlinkTar.Decompress(tempDir)
+					Expect(err).To(MatchError(ContainSubstring("failed to evaluate symlink")))
 					Expect(err).To(MatchError(ContainSubstring("no such file or directory")))
 				})
 			})

vacation/vacation_zip_test.go

@@ -82,7 +82,7 @@ func testVacationZip(t *testing.T, context spec.G, it spec.S) {
 			Expect(os.RemoveAll(tempDir)).To(Succeed())
 		})
 
-		it("downloads the dependency and unpackages it into the path", func() {
+		it("unpackages the archive into the path", func() {
 			var err error
 			err = zipArchive.Decompress(tempDir)
 			Expect(err).ToNot(HaveOccurred())
@@ -223,6 +223,7 @@ func testVacationZip(t *testing.T, context spec.G, it spec.S) {
 					readyArchive := vacation.NewZipArchive(buffer)
 
 					err := readyArchive.Decompress(tempDir)
+					Expect(err).To(MatchError(ContainSubstring("failed to evaluate symlink")))
 					Expect(err).To(MatchError(ContainSubstring("no such file or directory")))
 				})
 			})