image.go

package storage

import (
	"bufio"
	"context"
	"errors"
	"fmt"
	"io"
	"net"
	"os"
	"regexp"
	"sort"
	"strings"
	"sync"
	"time"

	"github.com/containers/image/v5/copy"
	"github.com/containers/image/v5/docker/reference"
	"github.com/containers/image/v5/pkg/shortnames"
	"github.com/containers/image/v5/signature"
	istorage "github.com/containers/image/v5/storage"
	"github.com/containers/image/v5/transports"
	"github.com/containers/image/v5/transports/alltransports"
	"github.com/containers/image/v5/types"
	encconfig "github.com/containers/ocicrypt/config"
	"github.com/containers/storage"
	"github.com/containers/storage/pkg/reexec"
	"github.com/containers/storage/pkg/unshare"

	"github.com/cri-o/cri-o/internal/storage/references"
	"github.com/cri-o/cri-o/pkg/config"
	json "github.com/json-iterator/go"
	digest "github.com/opencontainers/go-digest"
	specs "github.com/opencontainers/image-spec/specs-go/v1"
	"github.com/sirupsen/logrus"
)

const (
	minimumTruncatedIDLength = 3
)

// ImageResult wraps a subset of information about an image: its ID, its names,
// and the size, if known, or nil if it isn't.
type ImageResult struct {
	ID StorageImageID
	// May be nil if the image was referenced by ID and has no names.
	// It also has NO RELATIONSHIP to user input when returned by ImageStatusByName.
	SomeNameOfThisImage *RegistryImageReference
	RepoTags            []string
	RepoDigests         []string
	Size                *uint64
	Digest              digest.Digest
	ConfigDigest        digest.Digest
	User                string
	PreviousName        string
	Labels              map[string]string
	OCIConfig           *specs.Image
	Annotations         map[string]string
	Pinned              bool // pinned image to prevent it from garbage collection
}

type indexInfo struct {
	name   string
	secure bool
}

// A set of information that we prefer to cache about images, so that we can
// avoid having to reread them every time we need to return information about
// images.
// Every field in imageCacheItem are fixed properties of an "image", which in this
// context is the image.ID stored in c/storage, and thus don't need to be recomputed.
type imageCacheItem struct {
	config       *specs.Image
	size         *uint64
	configDigest digest.Digest
	info         *types.ImageInspectInfo
	annotations  map[string]string
}

type imageCache map[string]imageCacheItem

// WARNING: All of imageLookupService must be JSON-representable because it is included in pullImageArgs.
type imageLookupService struct {
	DefaultTransport      string
	InsecureRegistryCIDRs []*net.IPNet
	IndexConfigs          map[string]*indexInfo
}

type imageService struct {
	lookup               *imageLookupService
	store                storage.Store
	storageTransport     StorageTransport
	imageCache           imageCache
	imageCacheLock       sync.Mutex
	ctx                  context.Context
	config               *config.Config
	regexForPinnedImages []*regexp.Regexp
}

// ImageBeingPulled map[string]bool to keep track of the images haven't done pulling.
var ImageBeingPulled sync.Map

// CgroupPullConfiguration
// WARNING: All of imageLookupService must be JSON-representable because it is included in pullImageArgs.
type CgroupPullConfiguration struct {
	UseNewCgroup bool
	ParentCgroup string
}

// subset of copy.Options that is supported by reexec.
// WARNING: All ofImageCopyOptions must be JSON-representable because it is included in pullImageArgs.
type ImageCopyOptions struct {
	SourceCtx        *types.SystemContext
	DestinationCtx   *types.SystemContext
	OciDecryptConfig *encconfig.DecryptConfig
	ProgressInterval time.Duration
	Progress         chan types.ProgressProperties `json:"-"`
	CgroupPull       CgroupPullConfiguration
}

// ImageServer wraps up various CRI-related activities into a reusable
// implementation.
type ImageServer interface {
	// ListImages returns list of all images.
	ListImages(systemContext *types.SystemContext) ([]ImageResult, error)
	// ImageStatusByID returns status of a single image
	ImageStatusByID(systemContext *types.SystemContext, id StorageImageID) (*ImageResult, error)
	// ImageStatusByName returns status of an image tagged with name.
	ImageStatusByName(systemContext *types.SystemContext, name RegistryImageReference) (*ImageResult, error)

	// PrepareImage returns an Image where the config digest can be grabbed
	// for further analysis. Call Close() on the resulting image.
	PrepareImage(systemContext *types.SystemContext, imageName RegistryImageReference) (types.ImageCloser, error)
	// PullImage imports an image from the specified location.
	PullImage(ctx context.Context, imageName RegistryImageReference, options *ImageCopyOptions) (types.ImageReference, error)

	// DeleteImage deletes a storage image (impacting all its tags)
	DeleteImage(systemContext *types.SystemContext, id StorageImageID) error
	// UntagImage removes a name from the specified image, and if it was
	// the only name the image had, removes the image.
	UntagImage(systemContext *types.SystemContext, name RegistryImageReference) error

	// GetStore returns the reference to the storage library Store which
	// the image server uses to hold images, and is the destination used
	// when it's asked to pull an image.
	GetStore() storage.Store

	// HeuristicallyTryResolvingStringAsIDPrefix checks if heuristicInput could be a valid image ID or a prefix, and returns
	// a StorageImageID if so, or nil if the input can be something else.
	// DO NOT CALL THIS from in-process callers who know what their input is and don't NEED to involve heuristics.
	HeuristicallyTryResolvingStringAsIDPrefix(heuristicInput string) *StorageImageID
	// CandidatesForPotentiallyShortImageName resolves an image name into a set of fully-qualified image names (domain/repo/image:tag|@digest).
	// It will only return an empty slice if err != nil.
	CandidatesForPotentiallyShortImageName(systemContext *types.SystemContext, imageName string) ([]RegistryImageReference, error)

	// UpdatePinnedImagesList updates pinned and pause images list in imageService.
	UpdatePinnedImagesList(imageList []string)
}

func parseImageNames(image *storage.Image) (someName *RegistryImageReference, tags []reference.NamedTagged, digests []reference.Canonical, err error) {
	for _, nameString := range image.Names {
		name, err := reference.ParseNormalizedNamed(nameString)
		if err != nil {
			return nil, nil, nil, fmt.Errorf("invalid name %q in image %q: %w", nameString, image.ID, err)
		}
		if reference.IsNameOnly(name) {
			return nil, nil, nil, fmt.Errorf("invalid name %q in image %q, it has neither a tag nor a digest", nameString, image.ID)
		}
		switch name := name.(type) {
		case reference.Canonical:
			digests = append(digests, name)
		case reference.NamedTagged:
			tags = append(tags, name)
		default:
			return nil, nil, nil, fmt.Errorf("internal error, invalid name %q in image %q is !IsNameOnly but neither Canonical nor NamedTagged", nameString, image.ID)
		}
	}
	if len(digests) > 0 {
		best := references.RegistryImageReferenceFromRaw(digests[0])
		someName = &best
	}
	if len(tags) > 0 {
		best := references.RegistryImageReferenceFromRaw(tags[0])
		someName = &best
	}
	return someName, tags, digests, nil
}

func (svc *imageService) makeRepoDigests(knownRepoDigests []reference.Canonical, tags []reference.NamedTagged, img *storage.Image) (imageDigest digest.Digest, repoDigests []reference.Canonical) {
	// Look up the image's digests.
	imageDigest = img.Digest
	if imageDigest == "" {
		imgDigest, err := svc.store.ImageBigDataDigest(img.ID, storage.ImageDigestBigDataKey)
		if err != nil || imgDigest == "" {
			return "", knownRepoDigests
		}
		imageDigest = imgDigest
	}
	imageDigests := []digest.Digest{imageDigest}
	for _, anotherImageDigest := range img.Digests {
		if anotherImageDigest != imageDigest {
			imageDigests = append(imageDigests, anotherImageDigest)
		}
	}
	// We only want to supplement what's already explicitly in the list, so keep track of values
	// that we already know.
	digestMap := make(map[string]struct{})
	repoDigests = knownRepoDigests
	for _, repoDigest := range knownRepoDigests {
		digestMap[repoDigest.String()] = struct{}{}
	}
	// Collect all known repos...
	repos := []reference.Named{}
	for _, tagged := range tags {
		repos = append(repos, reference.TrimNamed(tagged))
	}
	for _, digested := range knownRepoDigests {
		repos = append(repos, reference.TrimNamed(digested))
	}
	// ... and combine each repo with each digest.
	// Note that this may create digested references that never existed on those registries.
	for _, repo := range repos {
		for _, imageDigest := range imageDigests {
			if imageRef, err3 := reference.WithDigest(repo, imageDigest); err3 == nil {
				if _, ok := digestMap[imageRef.String()]; !ok {
					repoDigests = append(repoDigests, imageRef)
					digestMap[imageRef.String()] = struct{}{}
				}
			}
		}
	}
	return imageDigest, repoDigests
}

func (svc *imageService) buildImageCacheItem(systemContext *types.SystemContext, ref types.ImageReference) (imageCacheItem, error) {
	imageFull, err := ref.NewImage(svc.ctx, systemContext)
	if err != nil {
		return imageCacheItem{}, err
	}
	defer imageFull.Close()
	configDigest := imageFull.ConfigInfo().Digest
	imageConfig, err := imageFull.OCIConfig(svc.ctx)
	if err != nil {
		return imageCacheItem{}, err
	}
	size := imageSize(imageFull)

	info, err := imageFull.Inspect(svc.ctx)
	if err != nil {
		return imageCacheItem{}, fmt.Errorf("inspecting image: %w", err)
	}

	rawSource, err := ref.NewImageSource(svc.ctx, systemContext)
	if err != nil {
		return imageCacheItem{}, err
	}
	defer rawSource.Close()

	topManifestBlob, manifestType, err := rawSource.GetManifest(svc.ctx, nil)
	if err != nil {
		return imageCacheItem{}, err
	}
	var ociManifest specs.Manifest
	if manifestType == specs.MediaTypeImageManifest {
		if err := json.Unmarshal(topManifestBlob, &ociManifest); err != nil {
			return imageCacheItem{}, err
		}
	}

	return imageCacheItem{
		config:       imageConfig,
		size:         size,
		configDigest: configDigest,
		info:         info,
		annotations:  ociManifest.Annotations,
	}, nil
}

func (svc *imageService) buildImageResult(image *storage.Image, cacheItem imageCacheItem) (ImageResult, error) {
	someName, tags, digests, err := parseImageNames(image)
	if err != nil {
		return ImageResult{}, err
	}
	imageDigest, repoDigests := svc.makeRepoDigests(digests, tags, image)

	repoTagStrings := make([]string, 0, len(tags))
	for _, t := range tags {
		repoTagStrings = append(repoTagStrings, t.String())
	}
	sort.Strings(repoTagStrings)
	repoDigestStrings := make([]string, 0, len(repoDigests))
	for _, d := range repoDigests {
		repoDigestStrings = append(repoDigestStrings, d.String())
	}
	sort.Strings(repoDigestStrings)

	previousName := ""
	if len(image.NamesHistory) > 0 {
		// Remove the tag because we can only keep the name as indicator
		split := strings.SplitN(image.NamesHistory[0], ":", 2)
		if len(split) > 0 {
			previousName = split[0]
		}
	}

	imagePinned := false
	for _, image := range image.Names {
		if FilterPinnedImage(image, svc.regexForPinnedImages) {
			imagePinned = true
			break
		}
	}
	return ImageResult{
		ID:                  storageImageIDFromImage(image),
		SomeNameOfThisImage: someName,
		RepoTags:            repoTagStrings,
		RepoDigests:         repoDigestStrings,
		Size:                cacheItem.size,
		Digest:              imageDigest,
		ConfigDigest:        cacheItem.configDigest,
		User:                cacheItem.config.Config.User,
		PreviousName:        previousName,
		Labels:              cacheItem.info.Labels,
		OCIConfig:           cacheItem.config,
		Annotations:         cacheItem.annotations,
		Pinned:              imagePinned,
	}, nil
}

func (svc *imageService) ListImages(systemContext *types.SystemContext) ([]ImageResult, error) {
	images, err := svc.store.Images()
	if err != nil {
		return nil, err
	}
	results := make([]ImageResult, 0, len(images))
	newImageCache := make(imageCache, len(images))
	for i := range images {
		image := &images[i]
		ref, err := istorage.Transport.NewStoreReference(svc.store, nil, image.ID)
		if err != nil {
			return nil, err
		}
		svc.imageCacheLock.Lock()
		cacheItem, ok := svc.imageCache[image.ID]
		svc.imageCacheLock.Unlock()
		if !ok {
			cacheItem, err = svc.buildImageCacheItem(systemContext, ref)
			if err != nil {
				if os.IsNotExist(err) && imageIsBeingPulled(image) { // skip reporting errors if the images haven't finished pulling
					continue
				}
				return nil, err
			}
		}

		newImageCache[image.ID] = cacheItem
		res, err := svc.buildImageResult(image, cacheItem)
		if err != nil {
			return nil, err
		}
		results = append(results, res)
	}
	// replace image cache with cache we just built
	// this invalidates all stale entries in cache
	svc.imageCacheLock.Lock()
	svc.imageCache = newImageCache
	svc.imageCacheLock.Unlock()
	return results, nil
}

func imageIsBeingPulled(image *storage.Image) bool {
	for _, name := range image.Names {
		if _, ok := ImageBeingPulled.Load(name); ok {
			return true
		}
	}
	return false
}

func (svc *imageService) ImageStatusByName(systemContext *types.SystemContext, name RegistryImageReference) (*ImageResult, error) {
	unstableRef, err := istorage.Transport.NewStoreReference(svc.store, name.Raw(), "")
	if err != nil {
		return nil, err
	}
	return svc.imageStatus(systemContext, unstableRef)
}

func (svc *imageService) ImageStatusByID(systemContext *types.SystemContext, id StorageImageID) (*ImageResult, error) {
	ref, err := id.imageRef(svc)
	if err != nil {
		return nil, err
	}
	return svc.imageStatus(systemContext, ref)
}

// imageStatus is the underlying implementation of ImageStatus* for a storage unstableRef.
func (svc *imageService) imageStatus(systemContext *types.SystemContext, unstableRef types.ImageReference) (*ImageResult, error) {
	resolvedRef, image, err := svc.storageTransport.ResolveReference(unstableRef)
	if err != nil {
		return nil, err
	}
	// unstableRef might point to different images over time. Use resolvedRef, which precisely
	// matches image, from now on.

	svc.imageCacheLock.Lock()
	cacheItem, ok := svc.imageCache[image.ID]
	svc.imageCacheLock.Unlock()

	if !ok {
		var err error
		cacheItem, err = svc.buildImageCacheItem(systemContext, resolvedRef) // Single-use-only, not actually cached
		if err != nil {
			return nil, err
		}
	}

	result, err := svc.buildImageResult(image, cacheItem)
	if err != nil {
		return nil, err
	}
	return &result, nil
}

func imageSize(img types.Image) *uint64 {
	if sum, err := img.Size(); err == nil {
		usum := uint64(sum)
		return &usum
	}
	return nil
}

// remoteImageReference creates an image reference for a CRI-O image reference
func (svc *imageLookupService) remoteImageReference(imageName RegistryImageReference) (types.ImageReference, error) {
	if svc.DefaultTransport == "" {
		return nil, errors.New("DefaultTransport is not set")
	}
	// This is not actually out-of-process; the ParseImageName input is defined as cross-process strings, so, close enough.
	// Practically, the only reasonable value of DefaultTransport is docker://, so this should ideally be replaced by
	// a call to c/image/v5/docker.NewReference, and DefaultTransport should be deprecated.
	return alltransports.ParseImageName(svc.DefaultTransport + imageName.StringForOutOfProcessConsumptionOnly())
}

// prepareReference creates an image reference from an image string and returns an updated types.SystemContext (never nil) for the image
func (svc *imageLookupService) prepareReference(inputSystemContext *types.SystemContext, imageName RegistryImageReference) (*types.SystemContext, types.ImageReference, error) {
	srcRef, err := svc.remoteImageReference(imageName)
	if err != nil {
		return nil, nil, err
	}

	sc := types.SystemContext{}
	if inputSystemContext != nil {
		sc = *inputSystemContext // A shallow copy
	}
	if secure := svc.isSecureIndex(imageName.Registry()); !secure {
		sc.DockerInsecureSkipTLSVerify = types.OptionalBoolTrue
	}
	return &sc, srcRef, nil
}

func (svc *imageService) PrepareImage(inputSystemContext *types.SystemContext, imageName RegistryImageReference) (types.ImageCloser, error) {
	systemContext, srcRef, err := svc.lookup.prepareReference(inputSystemContext, imageName)
	if err != nil {
		return nil, err
	}

	return srcRef.NewImage(svc.ctx, systemContext)
}

// nolint: gochecknoinits
func init() {
	reexec.Register("crio-pull-image", pullImageChild)
}

type pullImageArgs struct {
	Lookup       *imageLookupService
	ImageName    string // In the format of RegistryImageReference.StringForOutOfProcessConsumptionOnly()
	ParentCgroup string
	Options      *ImageCopyOptions

	StoreOptions storage.StoreOptions
}

type pullImageOutputItem struct {
	Progress *types.ProgressProperties `json:",omitempty"`
	Result   string                    `json:",omitempty"` // If not "", in the format of transport.ImageName()
}

func pullImageChild() {
	var args pullImageArgs

	if err := json.NewDecoder(os.NewFile(0, "stdin")).Decode(&args); err != nil {
		fmt.Fprintf(os.Stderr, "%v", err)
		os.Exit(1)
	}

	if err := moveSelfToCgroup(args.ParentCgroup); err != nil {
		fmt.Fprintf(os.Stderr, "%v", err)
		os.Exit(1)
	}

	store, err := storage.GetStore(args.StoreOptions)
	if err != nil {
		fmt.Fprintf(os.Stderr, "%v", err)
		os.Exit(1)
	}

	imageName, err := references.ParseRegistryImageReferenceFromOutOfProcessData(args.ImageName)
	if err != nil {
		fmt.Fprintf(os.Stderr, "%v", err)
		os.Exit(1)
	}

	output := make(chan pullImageOutputItem)
	outputWritten := make(chan struct{})
	go formatPullImageOutputItemGoroutine(os.Stdout, output, outputWritten)

	progress := make(chan types.ProgressProperties)
	go func() {
		for p := range progress {
			output <- pullImageOutputItem{Progress: &p}
		}
	}()
	args.Options.Progress = progress

	destRef, err := pullImageImplementation(context.Background(), args.Lookup, store, imageName, args.Options)
	if err != nil {
		fmt.Fprintf(os.Stderr, "%v", err)
		os.Exit(1)
	}
	output <- pullImageOutputItem{Result: transports.ImageName(destRef)}

	close(output)
	<-outputWritten

	os.Exit(0)
}

func formatPullImageOutputItemGoroutine(dest io.Writer, items <-chan pullImageOutputItem, outputWritten chan<- struct{}) {
	defer func() {
		outputWritten <- struct{}{}
	}()

	stream := json.NewStream(json.ConfigDefault, dest, 4096)
	for item := range items {
		stream.WriteVal(item)
		stream.WriteRaw("\n")
		if err := stream.Flush(); err != nil {
			fmt.Fprintf(os.Stderr, "%v", err)
			//nolint:gocritic // “exitAfterDefer: os.Exit will exit, and `defer func(){...}(...)` will not run”
			// If we fail writing output, outputWritten can never really be set, and it is no longer relevant.
			// Just abort.
			os.Exit(1)
		}
	}
}

func (svc *imageService) pullImageParent(ctx context.Context, imageName RegistryImageReference, parentCgroup string, options *ImageCopyOptions) (types.ImageReference, error) {
	progress := options.Progress
	// the first argument imageName is not used by the re-execed command but it is useful for debugging as it
	// shows in the ps output.
	cmd := reexec.CommandContext(ctx, "crio-pull-image", imageName.StringForOutOfProcessConsumptionOnly())
	stdout, err := cmd.StdoutPipe()
	if err != nil {
		return nil, fmt.Errorf("error getting stdout pipe for image copy process: %w", err)
	}
	defer stdout.Close()

	stderr, err := cmd.StderrPipe()
	if err != nil {
		return nil, fmt.Errorf("error getting stderr pipe for image copy process: %w", err)
	}
	defer stderr.Close()

	stdin, err := cmd.StdinPipe()
	if err != nil {
		return nil, fmt.Errorf("error getting stdin pipe for image copy process: %w", err)
	}

	stdinArguments := pullImageArgs{
		Lookup:       svc.lookup,
		Options:      options,
		ImageName:    imageName.StringForOutOfProcessConsumptionOnly(),
		ParentCgroup: parentCgroup,
		StoreOptions: storage.StoreOptions{
			RunRoot:            svc.store.RunRoot(),
			GraphRoot:          svc.store.GraphRoot(),
			GraphDriverName:    svc.store.GraphDriverName(),
			GraphDriverOptions: svc.store.GraphOptions(),
			UIDMap:             svc.store.UIDMap(),
			GIDMap:             svc.store.GIDMap(),
		},
	}

	stdinArguments.Options.Progress = nil
	if err := cmd.Start(); err != nil {
		return nil, err
	}
	if err := json.NewEncoder(stdin).Encode(&stdinArguments); err != nil {
		stdin.Close()
		if waitErr := cmd.Wait(); waitErr != nil {
			return nil, fmt.Errorf("%w: %w", waitErr, err)
		}
		return nil, fmt.Errorf("json encode to pipe failed: %w", err)
	}
	stdin.Close()

	resultChan := make(chan string)
	go func() {
		defer func() {
			close(resultChan) // Future reads, if any, will get "".
		}()

		decoder := json.NewDecoder(bufio.NewReader(stdout))
		if progress != nil {
			defer close(progress)
		}
		for decoder.More() {
			var item pullImageOutputItem
			if err := decoder.Decode(&item); err != nil {
				break
			}

			if item.Progress != nil && progress != nil {
				progress <- *item.Progress
			}
			if item.Result != "" {
				resultChan <- item.Result
			}
		}
	}()

	result := <-resultChan // Possibly "" if the process terminates before sending a result

	errOutput, errReadAll := io.ReadAll(stderr)
	if err := cmd.Wait(); err != nil {
		if errReadAll == nil && len(errOutput) > 0 {
			return nil, fmt.Errorf("pull image: %s", string(errOutput))
		}
		return nil, err
	}

	if result == "" {
		return nil, errors.New("pull child finished successfully but didn’t send a result")
	}

	destRef, err := alltransports.ParseImageName(result)
	if err != nil {
		return nil, err
	}
	return destRef, nil
}

func (svc *imageService) PullImage(ctx context.Context, imageName RegistryImageReference, options *ImageCopyOptions) (types.ImageReference, error) {
	if options.CgroupPull.UseNewCgroup {
		return svc.pullImageParent(ctx, imageName, options.CgroupPull.ParentCgroup, options)
	} else {
		return pullImageImplementation(ctx, svc.lookup, svc.store, imageName, options)
	}
}

// pullImageImplementation is called in PullImage, both directly and inside pullImageChild.
// NOTE: That means this code can run in a separate process, and it should not access any CRI-O global state.
//
// It returns a c/storage ImageReference for the destination.
func pullImageImplementation(ctx context.Context, lookup *imageLookupService, store storage.Store, imageName RegistryImageReference, options *ImageCopyOptions) (types.ImageReference, error) {
	srcSystemContext, srcRef, err := lookup.prepareReference(options.SourceCtx, imageName)
	if err != nil {
		return nil, err
	}
	destRef, err := istorage.Transport.NewStoreReference(store, imageName.Raw(), "")
	if err != nil {
		return nil, err
	}

	policy, err := signature.DefaultPolicy(options.SourceCtx)
	if err != nil {
		return nil, err
	}
	policyContext, err := signature.NewPolicyContext(policy)
	if err != nil {
		return nil, err
	}

	_, err = copy.Image(ctx, policyContext, destRef, srcRef, &copy.Options{
		SourceCtx:        srcSystemContext,
		DestinationCtx:   options.DestinationCtx,
		OciDecryptConfig: options.OciDecryptConfig,
		ProgressInterval: options.ProgressInterval,
		Progress:         options.Progress,
	})
	if err != nil {
		return nil, err
	}
	return destRef, err
}

func (svc *imageService) UntagImage(systemContext *types.SystemContext, name RegistryImageReference) error {
	unstableRef, err := istorage.Transport.NewStoreReference(svc.store, name.Raw(), "")
	if err != nil {
		return err
	}
	_, img, err := svc.storageTransport.ResolveReference(unstableRef)
	if err != nil {
		return err
	}
	// Do not use unstableRef from now on; if the tag moves, ref can refer to a different image.
	// Prefer img.ID or the other return value of ResolveReference.

	nameString := name.Raw().String()
	remainingNames := 0
	for _, imgName := range img.Names {
		if imgName != nameString {
			remainingNames += 1
		}
	}

	if remainingNames > 0 {
		return svc.store.RemoveNames(img.ID, []string{nameString})
	}
	// Note that the remainingNames check is unavoidably racy:
	// the image can be tagged with another name at this point.
	return svc.DeleteImage(systemContext, newExactStorageImageID(img.ID))
}

// DeleteImage deletes a storage image (impacting all its tags)
func (svc *imageService) DeleteImage(systemContext *types.SystemContext, id StorageImageID) error {
	ref, err := id.imageRef(svc)
	if err != nil {
		return err
	}

	return ref.DeleteImage(svc.ctx, systemContext)
}

func (svc *imageService) GetStore() storage.Store {
	return svc.store
}

func (svc *imageLookupService) isSecureIndex(indexName string) bool {
	if index, ok := svc.IndexConfigs[indexName]; ok {
		return index.secure
	}

	host, _, err := net.SplitHostPort(indexName)
	if err != nil {
		// assume indexName is of the form `host` without the port and go on.
		host = indexName
	}

	addrs, err := net.LookupIP(host)
	if err != nil {
		ip := net.ParseIP(host)
		if ip != nil {
			addrs = []net.IP{ip}
		}

		// if ip == nil, then `host` is neither an IP nor it could be looked up,
		// either because the index is unreachable, or because the index is behind an HTTP proxy.
		// So, len(addrs) == 0 and we're not aborting.
	}

	// Try CIDR notation only if addrs has any elements, i.e. if `host`'s IP could be determined.
	for _, addr := range addrs {
		for _, ipnet := range svc.InsecureRegistryCIDRs {
			// check if the addr falls in the subnet
			if ipnet.Contains(addr) {
				return false
			}
		}
	}

	return true
}

// HeuristicallyTryResolvingStringAsIDPrefix checks if heuristicInput could be a valid image ID or a prefix, and returns
// a StorageImageID if so, or nil if the input can be something else.
// DO NOT CALL THIS from in-process callers who know what their input is and don't NEED to involve heuristics.
func (svc *imageService) HeuristicallyTryResolvingStringAsIDPrefix(heuristicInput string) *StorageImageID {
	if res, err := parseStorageImageID(heuristicInput); err == nil {
		return &res // If it is already a full image ID, accept it.
	}
	if len(heuristicInput) >= minimumTruncatedIDLength {
		if img, err := svc.store.Image(heuristicInput); err == nil && strings.HasPrefix(img.ID, heuristicInput) {
			// It's a truncated version of the ID of an image that's present in local storage;
			// we need to expand it.
			res := storageImageIDFromImage(img)
			return &res
		}
	}
	return nil
}

// CandidatesForPotentiallyShortImageName resolves an image name into a set of fully-qualified image names (domain/repo/image:tag|@digest).
// It will only return an empty slice if err != nil.
func (svc *imageService) CandidatesForPotentiallyShortImageName(systemContext *types.SystemContext, imageName string) ([]RegistryImageReference, error) {
	// Always resolve unqualified names to all candidates. We should use a more secure mode once we settle on a shortname alias table.
	sc := types.SystemContext{}
	if systemContext != nil {
		sc = *systemContext // A shallow copy
	}
	disabled := types.ShortNameModeDisabled
	sc.ShortNameMode = &disabled
	resolved, err := shortnames.Resolve(&sc, imageName)
	if err != nil {
		return nil, err
	}

	if desc := resolved.Description(); desc != "" {
		logrus.Info(desc)
	}

	images := make([]RegistryImageReference, len(resolved.PullCandidates))
	for i := range resolved.PullCandidates {
		// Strip the tag from ambiguous image references that have a
		// digest as well (e.g.  `image:tag@sha256:123...`).  Such
		// image references are supported by docker but, due to their
		// ambiguity, explicitly not by containers/image.
		ref := resolved.PullCandidates[i].Value
		_, isTagged := ref.(reference.NamedTagged)
		canonical, isDigested := ref.(reference.Canonical)
		if isTagged && isDigested {
			canonical, err = reference.WithDigest(reference.TrimNamed(ref), canonical.Digest())
			if err != nil {
				return nil, err
			}
			ref = canonical
		}
		images[i] = references.RegistryImageReferenceFromRaw(ref)
	}

	return images, nil
}

// GetImageService returns an ImageServer that uses the passed-in store, and
// which will prepend the passed-in DefaultTransport value to an image name if
// a name that's passed to its PullImage() method can't be resolved to an image
// in the store and can't be resolved to a source on its own.
func GetImageService(ctx context.Context, store storage.Store, storageTransport StorageTransport, serverConfig *config.Config) (ImageServer, error) {
	if store == nil {
		var err error
		storeOpts, err := storage.DefaultStoreOptions(unshare.IsRootless(), unshare.GetRootlessUID())
		if err != nil {
			return nil, err
		}
		store, err = storage.GetStore(storeOpts)
		if err != nil {
			return nil, err
		}
	}
	if storageTransport == nil {
		storageTransport = nativeStorageTransport{}
	}
	ils := &imageLookupService{
		DefaultTransport:      serverConfig.DefaultTransport,
		IndexConfigs:          make(map[string]*indexInfo),
		InsecureRegistryCIDRs: make([]*net.IPNet, 0),
	}
	// add the sandbox/pause image configured by the user (if any) to the list of pinned_images.
	if serverConfig.PauseImage != "" {
		serverConfig.PinnedImages = append(serverConfig.PinnedImages, serverConfig.PauseImage)
	}
	is := &imageService{
		lookup:               ils,
		store:                store,
		storageTransport:     storageTransport,
		imageCache:           make(map[string]imageCacheItem),
		ctx:                  ctx,
		config:               serverConfig,
		regexForPinnedImages: CompileRegexpsForPinnedImages(serverConfig.PinnedImages),
	}

	serverConfig.InsecureRegistries = append(serverConfig.InsecureRegistries, "127.0.0.0/8")
	// Split --insecure-registry into CIDR and registry-specific settings.
	for _, r := range serverConfig.InsecureRegistries {
		// Check if CIDR was passed to --insecure-registry
		_, ipnet, err := net.ParseCIDR(r)
		if err == nil {
			// Valid CIDR.
			is.lookup.InsecureRegistryCIDRs = append(is.lookup.InsecureRegistryCIDRs, ipnet)
		} else {
			// Assume `host:port` if not CIDR.
			is.lookup.IndexConfigs[r] = &indexInfo{
				name:   r,
				secure: false,
			}
		}
	}

	return is, nil
}

// StorageTransport is a level of indirection to allow mocking istorage.ResolveReference
type StorageTransport interface {
	ResolveReference(ref types.ImageReference) (types.ImageReference, *storage.Image, error)
}

type nativeStorageTransport struct{}

func (st nativeStorageTransport) ResolveReference(ref types.ImageReference) (types.ImageReference, *storage.Image, error) {
	return istorage.ResolveReference(ref)
}

// UpdatePinnedImagesList updates pinned images list in imageService.
func (svc *imageService) UpdatePinnedImagesList(pinnedImages []string) {
	svc.regexForPinnedImages = CompileRegexpsForPinnedImages(pinnedImages)
}

// FilterPinnedImage checks if the given image needs to be pinned
// and excluded from kubelet's image GC.
func FilterPinnedImage(image string, pinnedImages []*regexp.Regexp) bool {
	if len(pinnedImages) == 0 {
		return false
	}

	for _, pinnedImage := range pinnedImages {
		if pinnedImage.MatchString(image) {
			return true
		}
	}
	return false
}

// CompileRegexpsForPinnedImages compiles regular expressions for the given
// list of pinned images.
func CompileRegexpsForPinnedImages(patterns []string) []*regexp.Regexp {
	regexps := make([]*regexp.Regexp, 0, len(patterns))
	for _, pattern := range patterns {
		var re *regexp.Regexp
		switch {
		case strings.HasPrefix(pattern, "*") && strings.HasSuffix(pattern, "*"):
			// keyword pattern
			keyword := regexp.QuoteMeta(pattern[1 : len(pattern)-1])
			re = regexp.MustCompile("(?i)" + keyword)
		case strings.HasSuffix(pattern, "*"):
			// glob pattern
			pattern = regexp.QuoteMeta(pattern[:len(pattern)-1]) + ".*"
			re = regexp.MustCompile("(?i)" + pattern)
		default:
			// exact pattern
			re = regexp.MustCompile("(?i)^" + regexp.QuoteMeta(pattern) + "$")
		}
		regexps = append(regexps, re)
	}

	return regexps
}