package distribution // import "github.com/docker/docker/distribution" import ( "context" "errors" "fmt" "io" "net/http" "runtime" "sort" "strconv" "strings" "github.com/Microsoft/hcsshim/osversion" "github.com/containerd/containerd/platforms" "github.com/docker/distribution" "github.com/docker/distribution/manifest/manifestlist" "github.com/docker/distribution/manifest/schema2" "github.com/docker/distribution/registry/client/transport" "github.com/docker/docker/pkg/system" specs "github.com/opencontainers/image-spec/specs-go/v1" "github.com/sirupsen/logrus" ) var _ distribution.Describable = &layerDescriptor{} func (ld *layerDescriptor) Descriptor() distribution.Descriptor { if ld.src.MediaType == schema2.MediaTypeForeignLayer && len(ld.src.URLs) > 0 { return ld.src } return distribution.Descriptor{} } func (ld *layerDescriptor) open(ctx context.Context) (distribution.ReadSeekCloser, error) { blobs := ld.repo.Blobs(ctx) rsc, err := blobs.Open(ctx, ld.digest) if len(ld.src.URLs) == 0 { return rsc, err } // We're done if the registry has this blob. if err == nil { // Seek does an HTTP GET. If it succeeds, the blob really is accessible. if _, err = rsc.Seek(0, io.SeekStart); err == nil { return rsc, nil } rsc.Close() } // Find the first URL that results in a 200 result code. for _, url := range ld.src.URLs { logrus.Debugf("Pulling %v from foreign URL %v", ld.digest, url) rsc = transport.NewHTTPReadSeeker(http.DefaultClient, url, nil) // Seek does an HTTP GET. If it succeeds, the blob really is accessible. _, err = rsc.Seek(0, io.SeekStart) if err == nil { break } logrus.Debugf("Download for %v failed: %v", ld.digest, err) rsc.Close() rsc = nil } return rsc, err } func filterManifests(manifests []manifestlist.ManifestDescriptor, p specs.Platform) []manifestlist.ManifestDescriptor { version := osversion.Get() osVersion := fmt.Sprintf("%d.%d.%d", version.MajorVersion, version.MinorVersion, version.Build) logrus.Debugf("will prefer Windows entries with version %s", osVersion) var matches []manifestlist.ManifestDescriptor foundWindowsMatch := false for _, manifestDescriptor := range manifests { if (manifestDescriptor.Platform.Architecture == runtime.GOARCH) && ((p.OS != "" && manifestDescriptor.Platform.OS == p.OS) || // Explicit user request for an OS we know we support (p.OS == "" && system.IsOSSupported(manifestDescriptor.Platform.OS))) { // No user requested OS, but one we can support if strings.EqualFold("windows", manifestDescriptor.Platform.OS) { if err := checkImageCompatibility("windows", manifestDescriptor.Platform.OSVersion); err != nil { continue } foundWindowsMatch = true } matches = append(matches, manifestDescriptor) logrus.Debugf("found match %s/%s %s with media type %s, digest %s", manifestDescriptor.Platform.OS, runtime.GOARCH, manifestDescriptor.Platform.OSVersion, manifestDescriptor.MediaType, manifestDescriptor.Digest.String()) } else { logrus.Debugf("ignoring %s/%s %s with media type %s, digest %s", manifestDescriptor.Platform.OS, manifestDescriptor.Platform.Architecture, manifestDescriptor.Platform.OSVersion, manifestDescriptor.MediaType, manifestDescriptor.Digest.String()) } } if foundWindowsMatch { sort.Stable(manifestsByVersion{osVersion, matches}) } return matches } func versionMatch(actual, expected string) bool { // Check whether the version matches up to the build, ignoring UBR return strings.HasPrefix(actual, expected+".") } type manifestsByVersion struct { version string list []manifestlist.ManifestDescriptor } func (mbv manifestsByVersion) Less(i, j int) bool { // TODO: Split version by parts and compare // TODO: Prefer versions which have a greater version number // Move compatible versions to the top, with no other ordering changes return (strings.EqualFold("windows", mbv.list[i].Platform.OS) && !strings.EqualFold("windows", mbv.list[j].Platform.OS)) || (versionMatch(mbv.list[i].Platform.OSVersion, mbv.version) && !versionMatch(mbv.list[j].Platform.OSVersion, mbv.version)) } func (mbv manifestsByVersion) Len() int { return len(mbv.list) } func (mbv manifestsByVersion) Swap(i, j int) { mbv.list[i], mbv.list[j] = mbv.list[j], mbv.list[i] } // checkImageCompatibility blocks pulling incompatible images based on a later OS build // Fixes https://github.com/moby/moby/issues/36184. func checkImageCompatibility(imageOS, imageOSVersion string) error { if imageOS == "windows" { hostOSV := osversion.Get() splitImageOSVersion := strings.Split(imageOSVersion, ".") // eg 10.0.16299.nnnn if len(splitImageOSVersion) >= 3 { if imageOSBuild, err := strconv.Atoi(splitImageOSVersion[2]); err == nil { if imageOSBuild > int(hostOSV.Build) { errMsg := fmt.Sprintf("a Windows version %s.%s.%s-based image is incompatible with a %s host", splitImageOSVersion[0], splitImageOSVersion[1], splitImageOSVersion[2], hostOSV.ToString()) logrus.Debugf(errMsg) return errors.New(errMsg) } } } } return nil } func formatPlatform(platform specs.Platform) string { if platform.OS == "" { platform = platforms.DefaultSpec() } return fmt.Sprintf("%s %s", platforms.Format(platform), osversion.Get().ToString()) }