From b80b2221df73d18ddc1291946f84142ec721541f Mon Sep 17 00:00:00 2001
From: Colin Walters <walters@verbum.org>
Date: Fri, 15 Sep 2023 08:53:45 -0400
Subject: [PATCH] proxy: Make `OpenImageOptional` work with `oci-archive:`

By adding the standard ENOENT to our list of errors.

I hit this while working on
https://github.com/coreos/rpm-ostree/pull/4598
which is a tool that builds base images and wants to query
if the image exists beforehand.

Signed-off-by: Colin Walters <walters@verbum.org>
---
 cmd/skopeo/proxy.go                           | 12 +++++++++++-
 integration/proxy_test.go                     | 19 +++++++++++++++++++
 .../image/v5/oci/archive/oci_transport.go     | 19 +++++++++++++------
 3 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/cmd/skopeo/proxy.go b/cmd/skopeo/proxy.go
index aab85365b1..40c8e85fc0 100644
--- a/cmd/skopeo/proxy.go
+++ b/cmd/skopeo/proxy.go
@@ -73,6 +73,7 @@ import (
 
 	"github.com/containers/image/v5/image"
 	"github.com/containers/image/v5/manifest"
+	ociarchive "github.com/containers/image/v5/oci/archive"
 	ocilayout "github.com/containers/image/v5/oci/layout"
 	"github.com/containers/image/v5/pkg/blobinfocache"
 	"github.com/containers/image/v5/transports"
@@ -229,13 +230,22 @@ func isDockerManifestUnknownError(err error) bool {
 	return ec.ErrorCode() == dockerdistributionapi.ErrorCodeManifestUnknown
 }
 
+func isOciImageNotFound(err error) bool {
+	var lerr ocilayout.ImageNotFoundError
+	if errors.As(err, &lerr) {
+		return true
+	}
+	var aerr ociarchive.ImageNotFoundError
+	return errors.As(err, &aerr)
+}
+
 // isNotFoundImageError heuristically attempts to determine whether an error
 // is saying the remote source couldn't find the image (as opposed to an
 // authentication error, an I/O error etc.)
 // TODO drive this into containers/image properly
 func isNotFoundImageError(err error) bool {
 	return isDockerManifestUnknownError(err) ||
-		errors.Is(err, ocilayout.ImageNotFoundError{})
+		isOciImageNotFound(err)
 }
 
 func (h *proxyHandler) openImageImpl(args []any, allowNotFound bool) (retReplyBuf replyBuf, retErr error) {
diff --git a/integration/proxy_test.go b/integration/proxy_test.go
index 826128da64..0907b9be5e 100644
--- a/integration/proxy_test.go
+++ b/integration/proxy_test.go
@@ -332,6 +332,15 @@ func runTestOpenImageOptionalNotFound(p *proxy, img string) error {
 	return nil
 }
 
+// Verify that we do see an error if the parent directory doesn't exist
+func runTestOpenImageOptionalNoParentDirectory(p *proxy) error {
+	_, err := p.callNoFd("OpenImageOptional", []any{"oci-archive:/no/such/parent/directory/foo.ociarchive"})
+	if err == nil {
+		return fmt.Errorf("Successfully opened nonexistent parent directory")
+	}
+	return nil
+}
+
 func (s *proxySuite) TestProxy() {
 	t := s.T()
 	p, err := newProxy()
@@ -354,4 +363,14 @@ func (s *proxySuite) TestProxy() {
 		err = fmt.Errorf("Testing optional image %s: %v", knownNotExtantImage, err)
 	}
 	assert.NoError(t, err)
+
+	nonExistentArchive := "oci-archive:/enoent"
+	err = runTestOpenImageOptionalNotFound(p, nonExistentArchive)
+	if err != nil {
+		err = fmt.Errorf("Testing optional image %s: %v", nonExistentArchive, err)
+	}
+	assert.NoError(t, err)
+
+	err = runTestOpenImageOptionalNoParentDirectory(p)
+	assert.NoError(t, err)
 }
diff --git a/vendor/github.com/containers/image/v5/oci/archive/oci_transport.go b/vendor/github.com/containers/image/v5/oci/archive/oci_transport.go
index 2a03feeeac..6d25383a3c 100644
--- a/vendor/github.com/containers/image/v5/oci/archive/oci_transport.go
+++ b/vendor/github.com/containers/image/v5/oci/archive/oci_transport.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io/fs"
 	"os"
 	"strings"
 
@@ -171,18 +172,24 @@ func createOCIRef(sys *types.SystemContext, image string) (tempDirOCIRef, error)
 
 // creates the temporary directory and copies the tarred content to it
 func createUntarTempDir(sys *types.SystemContext, ref ociArchiveReference) (tempDirOCIRef, error) {
-	tempDirRef, err := createOCIRef(sys, ref.image)
-	if err != nil {
-		return tempDirOCIRef{}, fmt.Errorf("creating oci reference: %w", err)
-	}
 	src := ref.resolvedFile
-	dst := tempDirRef.tempDirectory
 	// TODO: This can take quite some time, and should ideally be cancellable using a context.Context.
 	arch, err := os.Open(src)
 	if err != nil {
-		return tempDirOCIRef{}, err
+		if errors.Is(err, fs.ErrNotExist) {
+			return tempDirOCIRef{}, ImageNotFoundError{ref: ref}
+		} else {
+			return tempDirOCIRef{}, err
+		}
 	}
 	defer arch.Close()
+
+	tempDirRef, err := createOCIRef(sys, ref.image)
+	if err != nil {
+		return tempDirOCIRef{}, fmt.Errorf("creating oci reference: %w", err)
+	}
+	dst := tempDirRef.tempDirectory
+
 	if err := archive.NewDefaultArchiver().Untar(arch, dst, &archive.TarOptions{NoLchown: true}); err != nil {
 		if err := tempDirRef.deleteTempDir(); err != nil {
 			return tempDirOCIRef{}, fmt.Errorf("deleting temp directory %q: %w", tempDirRef.tempDirectory, err)