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Diffstat (limited to 'vendor/github.com/containerd/stargz-snapshotter/estargz/build.go')
-rw-r--r--vendor/github.com/containerd/stargz-snapshotter/estargz/build.go628
1 files changed, 628 insertions, 0 deletions
diff --git a/vendor/github.com/containerd/stargz-snapshotter/estargz/build.go b/vendor/github.com/containerd/stargz-snapshotter/estargz/build.go
new file mode 100644
index 000000000..708b26689
--- /dev/null
+++ b/vendor/github.com/containerd/stargz-snapshotter/estargz/build.go
@@ -0,0 +1,628 @@
+/*
+ Copyright The containerd Authors.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+*/
+
+/*
+ Copyright 2019 The Go Authors. All rights reserved.
+ Use of this source code is governed by a BSD-style
+ license that can be found in the LICENSE file.
+*/
+
+package estargz
+
+import (
+ "archive/tar"
+ "bytes"
+ "compress/gzip"
+ "fmt"
+ "io"
+ "io/ioutil"
+ "os"
+ "path"
+ "runtime"
+ "strings"
+ "sync"
+
+ "github.com/containerd/stargz-snapshotter/estargz/errorutil"
+ "github.com/klauspost/compress/zstd"
+ digest "github.com/opencontainers/go-digest"
+ "github.com/pkg/errors"
+ "golang.org/x/sync/errgroup"
+)
+
+type options struct {
+ chunkSize int
+ compressionLevel int
+ prioritizedFiles []string
+ missedPrioritizedFiles *[]string
+ compression Compression
+}
+
+type Option func(o *options) error
+
+// WithChunkSize option specifies the chunk size of eStargz blob to build.
+func WithChunkSize(chunkSize int) Option {
+ return func(o *options) error {
+ o.chunkSize = chunkSize
+ return nil
+ }
+}
+
+// WithCompressionLevel option specifies the gzip compression level.
+// The default is gzip.BestCompression.
+// See also: https://godoc.org/compress/gzip#pkg-constants
+func WithCompressionLevel(level int) Option {
+ return func(o *options) error {
+ o.compressionLevel = level
+ return nil
+ }
+}
+
+// WithPrioritizedFiles option specifies the list of prioritized files.
+// These files must be complete paths that are absolute or relative to "/"
+// For example, all of "foo/bar", "/foo/bar", "./foo/bar" and "../foo/bar"
+// are treated as "/foo/bar".
+func WithPrioritizedFiles(files []string) Option {
+ return func(o *options) error {
+ o.prioritizedFiles = files
+ return nil
+ }
+}
+
+// WithAllowPrioritizeNotFound makes Build continue the execution even if some
+// of prioritized files specified by WithPrioritizedFiles option aren't found
+// in the input tar. Instead, this records all missed file names to the passed
+// slice.
+func WithAllowPrioritizeNotFound(missedFiles *[]string) Option {
+ return func(o *options) error {
+ if missedFiles == nil {
+ return fmt.Errorf("WithAllowPrioritizeNotFound: slice must be passed")
+ }
+ o.missedPrioritizedFiles = missedFiles
+ return nil
+ }
+}
+
+// WithCompression specifies compression algorithm to be used.
+// Default is gzip.
+func WithCompression(compression Compression) Option {
+ return func(o *options) error {
+ o.compression = compression
+ return nil
+ }
+}
+
+// Blob is an eStargz blob.
+type Blob struct {
+ io.ReadCloser
+ diffID digest.Digester
+ tocDigest digest.Digest
+}
+
+// DiffID returns the digest of uncompressed blob.
+// It is only valid to call DiffID after Close.
+func (b *Blob) DiffID() digest.Digest {
+ return b.diffID.Digest()
+}
+
+// TOCDigest returns the digest of uncompressed TOC JSON.
+func (b *Blob) TOCDigest() digest.Digest {
+ return b.tocDigest
+}
+
+// Build builds an eStargz blob which is an extended version of stargz, from a blob (gzip, zstd
+// or plain tar) passed through the argument. If there are some prioritized files are listed in
+// the option, these files are grouped as "prioritized" and can be used for runtime optimization
+// (e.g. prefetch). This function builds a blob in parallel, with dividing that blob into several
+// (at least the number of runtime.GOMAXPROCS(0)) sub-blobs.
+func Build(tarBlob *io.SectionReader, opt ...Option) (_ *Blob, rErr error) {
+ var opts options
+ opts.compressionLevel = gzip.BestCompression // BestCompression by default
+ for _, o := range opt {
+ if err := o(&opts); err != nil {
+ return nil, err
+ }
+ }
+ if opts.compression == nil {
+ opts.compression = newGzipCompressionWithLevel(opts.compressionLevel)
+ }
+ layerFiles := newTempFiles()
+ defer func() {
+ if rErr != nil {
+ if err := layerFiles.CleanupAll(); err != nil {
+ rErr = errors.Wrapf(rErr, "failed to cleanup tmp files: %v", err)
+ }
+ }
+ }()
+ tarBlob, err := decompressBlob(tarBlob, layerFiles)
+ if err != nil {
+ return nil, err
+ }
+ entries, err := sortEntries(tarBlob, opts.prioritizedFiles, opts.missedPrioritizedFiles)
+ if err != nil {
+ return nil, err
+ }
+ tarParts := divideEntries(entries, runtime.GOMAXPROCS(0))
+ writers := make([]*Writer, len(tarParts))
+ payloads := make([]*os.File, len(tarParts))
+ var mu sync.Mutex
+ var eg errgroup.Group
+ for i, parts := range tarParts {
+ i, parts := i, parts
+ // builds verifiable stargz sub-blobs
+ eg.Go(func() error {
+ esgzFile, err := layerFiles.TempFile("", "esgzdata")
+ if err != nil {
+ return err
+ }
+ sw := NewWriterWithCompressor(esgzFile, opts.compression)
+ sw.ChunkSize = opts.chunkSize
+ if err := sw.AppendTar(readerFromEntries(parts...)); err != nil {
+ return err
+ }
+ mu.Lock()
+ writers[i] = sw
+ payloads[i] = esgzFile
+ mu.Unlock()
+ return nil
+ })
+ }
+ if err := eg.Wait(); err != nil {
+ rErr = err
+ return nil, err
+ }
+ tocAndFooter, tocDgst, err := closeWithCombine(opts.compressionLevel, writers...)
+ if err != nil {
+ rErr = err
+ return nil, err
+ }
+ var rs []io.Reader
+ for _, p := range payloads {
+ fs, err := fileSectionReader(p)
+ if err != nil {
+ return nil, err
+ }
+ rs = append(rs, fs)
+ }
+ diffID := digest.Canonical.Digester()
+ pr, pw := io.Pipe()
+ go func() {
+ r, err := opts.compression.Reader(io.TeeReader(io.MultiReader(append(rs, tocAndFooter)...), pw))
+ if err != nil {
+ pw.CloseWithError(err)
+ return
+ }
+ defer r.Close()
+ if _, err := io.Copy(diffID.Hash(), r); err != nil {
+ pw.CloseWithError(err)
+ return
+ }
+ pw.Close()
+ }()
+ return &Blob{
+ ReadCloser: readCloser{
+ Reader: pr,
+ closeFunc: layerFiles.CleanupAll,
+ },
+ tocDigest: tocDgst,
+ diffID: diffID,
+ }, nil
+}
+
+// closeWithCombine takes unclosed Writers and close them. This also returns the
+// toc that combined all Writers into.
+// Writers doesn't write TOC and footer to the underlying writers so they can be
+// combined into a single eStargz and tocAndFooter returned by this function can
+// be appended at the tail of that combined blob.
+func closeWithCombine(compressionLevel int, ws ...*Writer) (tocAndFooterR io.Reader, tocDgst digest.Digest, err error) {
+ if len(ws) == 0 {
+ return nil, "", fmt.Errorf("at least one writer must be passed")
+ }
+ for _, w := range ws {
+ if w.closed {
+ return nil, "", fmt.Errorf("writer must be unclosed")
+ }
+ defer func(w *Writer) { w.closed = true }(w)
+ if err := w.closeGz(); err != nil {
+ return nil, "", err
+ }
+ if err := w.bw.Flush(); err != nil {
+ return nil, "", err
+ }
+ }
+ var (
+ mtoc = new(JTOC)
+ currentOffset int64
+ )
+ mtoc.Version = ws[0].toc.Version
+ for _, w := range ws {
+ for _, e := range w.toc.Entries {
+ // Recalculate Offset of non-empty files/chunks
+ if (e.Type == "reg" && e.Size > 0) || e.Type == "chunk" {
+ e.Offset += currentOffset
+ }
+ mtoc.Entries = append(mtoc.Entries, e)
+ }
+ if w.toc.Version > mtoc.Version {
+ mtoc.Version = w.toc.Version
+ }
+ currentOffset += w.cw.n
+ }
+
+ return tocAndFooter(ws[0].compressor, mtoc, currentOffset)
+}
+
+func tocAndFooter(compressor Compressor, toc *JTOC, offset int64) (io.Reader, digest.Digest, error) {
+ buf := new(bytes.Buffer)
+ tocDigest, err := compressor.WriteTOCAndFooter(buf, offset, toc, nil)
+ if err != nil {
+ return nil, "", err
+ }
+ return buf, tocDigest, nil
+}
+
+// divideEntries divides passed entries to the parts at least the number specified by the
+// argument.
+func divideEntries(entries []*entry, minPartsNum int) (set [][]*entry) {
+ var estimatedSize int64
+ for _, e := range entries {
+ estimatedSize += e.header.Size
+ }
+ unitSize := estimatedSize / int64(minPartsNum)
+ var (
+ nextEnd = unitSize
+ offset int64
+ )
+ set = append(set, []*entry{})
+ for _, e := range entries {
+ set[len(set)-1] = append(set[len(set)-1], e)
+ offset += e.header.Size
+ if offset > nextEnd {
+ set = append(set, []*entry{})
+ nextEnd += unitSize
+ }
+ }
+ return
+}
+
+var errNotFound = errors.New("not found")
+
+// sortEntries reads the specified tar blob and returns a list of tar entries.
+// If some of prioritized files are specified, the list starts from these
+// files with keeping the order specified by the argument.
+func sortEntries(in io.ReaderAt, prioritized []string, missedPrioritized *[]string) ([]*entry, error) {
+
+ // Import tar file.
+ intar, err := importTar(in)
+ if err != nil {
+ return nil, errors.Wrap(err, "failed to sort")
+ }
+
+ // Sort the tar file respecting to the prioritized files list.
+ sorted := &tarFile{}
+ for _, l := range prioritized {
+ if err := moveRec(l, intar, sorted); err != nil {
+ if errors.Is(err, errNotFound) && missedPrioritized != nil {
+ *missedPrioritized = append(*missedPrioritized, l)
+ continue // allow not found
+ }
+ return nil, errors.Wrap(err, "failed to sort tar entries")
+ }
+ }
+ if len(prioritized) == 0 {
+ sorted.add(&entry{
+ header: &tar.Header{
+ Name: NoPrefetchLandmark,
+ Typeflag: tar.TypeReg,
+ Size: int64(len([]byte{landmarkContents})),
+ },
+ payload: bytes.NewReader([]byte{landmarkContents}),
+ })
+ } else {
+ sorted.add(&entry{
+ header: &tar.Header{
+ Name: PrefetchLandmark,
+ Typeflag: tar.TypeReg,
+ Size: int64(len([]byte{landmarkContents})),
+ },
+ payload: bytes.NewReader([]byte{landmarkContents}),
+ })
+ }
+
+ // Dump all entry and concatinate them.
+ return append(sorted.dump(), intar.dump()...), nil
+}
+
+// readerFromEntries returns a reader of tar archive that contains entries passed
+// through the arguments.
+func readerFromEntries(entries ...*entry) io.Reader {
+ pr, pw := io.Pipe()
+ go func() {
+ tw := tar.NewWriter(pw)
+ defer tw.Close()
+ for _, entry := range entries {
+ if err := tw.WriteHeader(entry.header); err != nil {
+ pw.CloseWithError(fmt.Errorf("Failed to write tar header: %v", err))
+ return
+ }
+ if _, err := io.Copy(tw, entry.payload); err != nil {
+ pw.CloseWithError(fmt.Errorf("Failed to write tar payload: %v", err))
+ return
+ }
+ }
+ pw.Close()
+ }()
+ return pr
+}
+
+func importTar(in io.ReaderAt) (*tarFile, error) {
+ tf := &tarFile{}
+ pw, err := newCountReader(in)
+ if err != nil {
+ return nil, errors.Wrap(err, "failed to make position watcher")
+ }
+ tr := tar.NewReader(pw)
+
+ // Walk through all nodes.
+ for {
+ // Fetch and parse next header.
+ h, err := tr.Next()
+ if err != nil {
+ if err == io.EOF {
+ break
+ } else {
+ return nil, errors.Wrap(err, "failed to parse tar file")
+ }
+ }
+ switch cleanEntryName(h.Name) {
+ case PrefetchLandmark, NoPrefetchLandmark:
+ // Ignore existing landmark
+ continue
+ }
+
+ // Add entry. If it already exists, replace it.
+ if _, ok := tf.get(h.Name); ok {
+ tf.remove(h.Name)
+ }
+ tf.add(&entry{
+ header: h,
+ payload: io.NewSectionReader(in, pw.currentPos(), h.Size),
+ })
+ }
+
+ return tf, nil
+}
+
+func moveRec(name string, in *tarFile, out *tarFile) error {
+ name = cleanEntryName(name)
+ if name == "" { // root directory. stop recursion.
+ if e, ok := in.get(name); ok {
+ // entry of the root directory exists. we should move it as well.
+ // this case will occur if tar entries are prefixed with "./", "/", etc.
+ out.add(e)
+ in.remove(name)
+ }
+ return nil
+ }
+
+ _, okIn := in.get(name)
+ _, okOut := out.get(name)
+ if !okIn && !okOut {
+ return errors.Wrapf(errNotFound, "file: %q", name)
+ }
+
+ parent, _ := path.Split(strings.TrimSuffix(name, "/"))
+ if err := moveRec(parent, in, out); err != nil {
+ return err
+ }
+ if e, ok := in.get(name); ok && e.header.Typeflag == tar.TypeLink {
+ if err := moveRec(e.header.Linkname, in, out); err != nil {
+ return err
+ }
+ }
+ if e, ok := in.get(name); ok {
+ out.add(e)
+ in.remove(name)
+ }
+ return nil
+}
+
+type entry struct {
+ header *tar.Header
+ payload io.ReadSeeker
+}
+
+type tarFile struct {
+ index map[string]*entry
+ stream []*entry
+}
+
+func (f *tarFile) add(e *entry) {
+ if f.index == nil {
+ f.index = make(map[string]*entry)
+ }
+ f.index[cleanEntryName(e.header.Name)] = e
+ f.stream = append(f.stream, e)
+}
+
+func (f *tarFile) remove(name string) {
+ name = cleanEntryName(name)
+ if f.index != nil {
+ delete(f.index, name)
+ }
+ var filtered []*entry
+ for _, e := range f.stream {
+ if cleanEntryName(e.header.Name) == name {
+ continue
+ }
+ filtered = append(filtered, e)
+ }
+ f.stream = filtered
+}
+
+func (f *tarFile) get(name string) (e *entry, ok bool) {
+ if f.index == nil {
+ return nil, false
+ }
+ e, ok = f.index[cleanEntryName(name)]
+ return
+}
+
+func (f *tarFile) dump() []*entry {
+ return f.stream
+}
+
+type readCloser struct {
+ io.Reader
+ closeFunc func() error
+}
+
+func (rc readCloser) Close() error {
+ return rc.closeFunc()
+}
+
+func fileSectionReader(file *os.File) (*io.SectionReader, error) {
+ info, err := file.Stat()
+ if err != nil {
+ return nil, err
+ }
+ return io.NewSectionReader(file, 0, info.Size()), nil
+}
+
+func newTempFiles() *tempFiles {
+ return &tempFiles{}
+}
+
+type tempFiles struct {
+ files []*os.File
+ filesMu sync.Mutex
+}
+
+func (tf *tempFiles) TempFile(dir, pattern string) (*os.File, error) {
+ f, err := ioutil.TempFile(dir, pattern)
+ if err != nil {
+ return nil, err
+ }
+ tf.filesMu.Lock()
+ tf.files = append(tf.files, f)
+ tf.filesMu.Unlock()
+ return f, nil
+}
+
+func (tf *tempFiles) CleanupAll() error {
+ tf.filesMu.Lock()
+ defer tf.filesMu.Unlock()
+ var allErr []error
+ for _, f := range tf.files {
+ if err := f.Close(); err != nil {
+ allErr = append(allErr, err)
+ }
+ if err := os.Remove(f.Name()); err != nil {
+ allErr = append(allErr, err)
+ }
+ }
+ tf.files = nil
+ return errorutil.Aggregate(allErr)
+}
+
+func newCountReader(r io.ReaderAt) (*countReader, error) {
+ pos := int64(0)
+ return &countReader{r: r, cPos: &pos}, nil
+}
+
+type countReader struct {
+ r io.ReaderAt
+ cPos *int64
+
+ mu sync.Mutex
+}
+
+func (cr *countReader) Read(p []byte) (int, error) {
+ cr.mu.Lock()
+ defer cr.mu.Unlock()
+
+ n, err := cr.r.ReadAt(p, *cr.cPos)
+ if err == nil {
+ *cr.cPos += int64(n)
+ }
+ return n, err
+}
+
+func (cr *countReader) Seek(offset int64, whence int) (int64, error) {
+ cr.mu.Lock()
+ defer cr.mu.Unlock()
+
+ switch whence {
+ default:
+ return 0, fmt.Errorf("Unknown whence: %v", whence)
+ case io.SeekStart:
+ case io.SeekCurrent:
+ offset += *cr.cPos
+ case io.SeekEnd:
+ return 0, fmt.Errorf("Unsupported whence: %v", whence)
+ }
+
+ if offset < 0 {
+ return 0, fmt.Errorf("invalid offset")
+ }
+ *cr.cPos = offset
+ return offset, nil
+}
+
+func (cr *countReader) currentPos() int64 {
+ cr.mu.Lock()
+ defer cr.mu.Unlock()
+
+ return *cr.cPos
+}
+
+func decompressBlob(org *io.SectionReader, tmp *tempFiles) (*io.SectionReader, error) {
+ if org.Size() < 4 {
+ return org, nil
+ }
+ src := make([]byte, 4)
+ if _, err := org.Read(src); err != nil && err != io.EOF {
+ return nil, err
+ }
+ var dR io.Reader
+ if bytes.Equal([]byte{0x1F, 0x8B, 0x08}, src[:3]) {
+ // gzip
+ dgR, err := gzip.NewReader(io.NewSectionReader(org, 0, org.Size()))
+ if err != nil {
+ return nil, err
+ }
+ defer dgR.Close()
+ dR = io.Reader(dgR)
+ } else if bytes.Equal([]byte{0x28, 0xb5, 0x2f, 0xfd}, src[:4]) {
+ // zstd
+ dzR, err := zstd.NewReader(io.NewSectionReader(org, 0, org.Size()))
+ if err != nil {
+ return nil, err
+ }
+ defer dzR.Close()
+ dR = io.Reader(dzR)
+ } else {
+ // uncompressed
+ return io.NewSectionReader(org, 0, org.Size()), nil
+ }
+ b, err := tmp.TempFile("", "uncompresseddata")
+ if err != nil {
+ return nil, err
+ }
+ if _, err := io.Copy(b, dR); err != nil {
+ return nil, err
+ }
+ return fileSectionReader(b)
+}
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2024-10-01 02:22:07 +0000