Merge pull request #1903 from darrenstahlmsft/ArchiveOpts

Implement Archive.apply on Windows
This commit is contained in:
Michael Crosby 2018-01-02 16:08:36 -05:00 committed by GitHub
commit e479165a38
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
12 changed files with 688 additions and 101 deletions

52
archive/strconv.go Normal file
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@ -0,0 +1,52 @@
// +build windows
package archive
import (
"strconv"
"strings"
"time"
"github.com/dmcgowan/go-tar"
)
// Forked from https://github.com/golang/go/blob/master/src/archive/tar/strconv.go
// as archive/tar doesn't support CreationTime, but does handle PAX time parsing,
// and there's no need to re-invent the wheel.
// parsePAXTime takes a string of the form %d.%d as described in the PAX
// specification. Note that this implementation allows for negative timestamps,
// which is allowed for by the PAX specification, but not always portable.
func parsePAXTime(s string) (time.Time, error) {
const maxNanoSecondDigits = 9
// Split string into seconds and sub-seconds parts.
ss, sn := s, ""
if pos := strings.IndexByte(s, '.'); pos >= 0 {
ss, sn = s[:pos], s[pos+1:]
}
// Parse the seconds.
secs, err := strconv.ParseInt(ss, 10, 64)
if err != nil {
return time.Time{}, tar.ErrHeader
}
if len(sn) == 0 {
return time.Unix(secs, 0), nil // No sub-second values
}
// Parse the nanoseconds.
if strings.Trim(sn, "0123456789") != "" {
return time.Time{}, tar.ErrHeader
}
if len(sn) < maxNanoSecondDigits {
sn += strings.Repeat("0", maxNanoSecondDigits-len(sn)) // Right pad
} else {
sn = sn[:maxNanoSecondDigits] // Right truncate
}
nsecs, _ := strconv.ParseInt(sn, 10, 64) // Must succeed
if len(ss) > 0 && ss[0] == '-' {
return time.Unix(secs, -1*int64(nsecs)), nil // Negative correction
}
return time.Unix(secs, int64(nsecs)), nil
}

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@ -87,12 +87,23 @@ const (
// Apply applies a tar stream of an OCI style diff tar.
// See https://github.com/opencontainers/image-spec/blob/master/layer.md#applying-changesets
func Apply(ctx context.Context, root string, r io.Reader) (int64, error) {
func Apply(ctx context.Context, root string, r io.Reader, opts ...ApplyOpt) (int64, error) {
root = filepath.Clean(root)
var options ApplyOptions
for _, opt := range opts {
if err := opt(&options); err != nil {
return 0, errors.Wrap(err, "failed to apply option")
}
}
return apply(ctx, root, tar.NewReader(r), options)
}
// applyNaive applies a tar stream of an OCI style diff tar.
// See https://github.com/opencontainers/image-spec/blob/master/layer.md#applying-changesets
func applyNaive(ctx context.Context, root string, tr *tar.Reader, options ApplyOptions) (size int64, err error) {
var (
tr = tar.NewReader(r)
size int64
dirs []*tar.Header
// Used for handling opaque directory markers which
@ -285,6 +296,99 @@ func Apply(ctx context.Context, root string, r io.Reader) (int64, error) {
return size, nil
}
func createTarFile(ctx context.Context, path, extractDir string, hdr *tar.Header, reader io.Reader) error {
// hdr.Mode is in linux format, which we can use for syscalls,
// but for os.Foo() calls we need the mode converted to os.FileMode,
// so use hdrInfo.Mode() (they differ for e.g. setuid bits)
hdrInfo := hdr.FileInfo()
switch hdr.Typeflag {
case tar.TypeDir:
// Create directory unless it exists as a directory already.
// In that case we just want to merge the two
if fi, err := os.Lstat(path); !(err == nil && fi.IsDir()) {
if err := mkdir(path, hdrInfo.Mode()); err != nil {
return err
}
}
case tar.TypeReg, tar.TypeRegA:
file, err := openFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, hdrInfo.Mode())
if err != nil {
return err
}
_, err = copyBuffered(ctx, file, reader)
if err1 := file.Close(); err == nil {
err = err1
}
if err != nil {
return err
}
case tar.TypeBlock, tar.TypeChar:
// Handle this is an OS-specific way
if err := handleTarTypeBlockCharFifo(hdr, path); err != nil {
return err
}
case tar.TypeFifo:
// Handle this is an OS-specific way
if err := handleTarTypeBlockCharFifo(hdr, path); err != nil {
return err
}
case tar.TypeLink:
targetPath, err := fs.RootPath(extractDir, hdr.Linkname)
if err != nil {
return err
}
if err := os.Link(targetPath, path); err != nil {
return err
}
case tar.TypeSymlink:
if err := os.Symlink(hdr.Linkname, path); err != nil {
return err
}
case tar.TypeXGlobalHeader:
log.G(ctx).Debug("PAX Global Extended Headers found and ignored")
return nil
default:
return errors.Errorf("unhandled tar header type %d\n", hdr.Typeflag)
}
// Lchown is not supported on Windows.
if runtime.GOOS != "windows" {
if err := os.Lchown(path, hdr.Uid, hdr.Gid); err != nil {
return err
}
}
for key, value := range hdr.PAXRecords {
if strings.HasPrefix(key, paxSchilyXattr) {
key = key[len(paxSchilyXattr):]
if err := setxattr(path, key, value); err != nil {
if errors.Cause(err) == syscall.ENOTSUP {
log.G(ctx).WithError(err).Warnf("ignored xattr %s in archive", key)
continue
}
return err
}
}
}
// There is no LChmod, so ignore mode for symlink. Also, this
// must happen after chown, as that can modify the file mode
if err := handleLChmod(hdr, path, hdrInfo); err != nil {
return err
}
return chtimes(path, boundTime(latestTime(hdr.AccessTime, hdr.ModTime)), boundTime(hdr.ModTime))
}
type changeWriter struct {
tw *tar.Writer
source string
@ -442,99 +546,6 @@ func (cw *changeWriter) Close() error {
return nil
}
func createTarFile(ctx context.Context, path, extractDir string, hdr *tar.Header, reader io.Reader) error {
// hdr.Mode is in linux format, which we can use for syscalls,
// but for os.Foo() calls we need the mode converted to os.FileMode,
// so use hdrInfo.Mode() (they differ for e.g. setuid bits)
hdrInfo := hdr.FileInfo()
switch hdr.Typeflag {
case tar.TypeDir:
// Create directory unless it exists as a directory already.
// In that case we just want to merge the two
if fi, err := os.Lstat(path); !(err == nil && fi.IsDir()) {
if err := mkdir(path, hdrInfo.Mode()); err != nil {
return err
}
}
case tar.TypeReg, tar.TypeRegA:
file, err := openFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, hdrInfo.Mode())
if err != nil {
return err
}
_, err = copyBuffered(ctx, file, reader)
if err1 := file.Close(); err == nil {
err = err1
}
if err != nil {
return err
}
case tar.TypeBlock, tar.TypeChar:
// Handle this is an OS-specific way
if err := handleTarTypeBlockCharFifo(hdr, path); err != nil {
return err
}
case tar.TypeFifo:
// Handle this is an OS-specific way
if err := handleTarTypeBlockCharFifo(hdr, path); err != nil {
return err
}
case tar.TypeLink:
targetPath, err := fs.RootPath(extractDir, hdr.Linkname)
if err != nil {
return err
}
if err := os.Link(targetPath, path); err != nil {
return err
}
case tar.TypeSymlink:
if err := os.Symlink(hdr.Linkname, path); err != nil {
return err
}
case tar.TypeXGlobalHeader:
log.G(ctx).Debug("PAX Global Extended Headers found and ignored")
return nil
default:
return errors.Errorf("unhandled tar header type %d\n", hdr.Typeflag)
}
// Lchown is not supported on Windows.
if runtime.GOOS != "windows" {
if err := os.Lchown(path, hdr.Uid, hdr.Gid); err != nil {
return err
}
}
for key, value := range hdr.PAXRecords {
if strings.HasPrefix(key, paxSchilyXattr) {
key = key[len(paxSchilyXattr):]
if err := setxattr(path, key, value); err != nil {
if errors.Cause(err) == syscall.ENOTSUP {
log.G(ctx).WithError(err).Warnf("ignored xattr %s in archive", key)
continue
}
return err
}
}
}
// There is no LChmod, so ignore mode for symlink. Also, this
// must happen after chown, as that can modify the file mode
if err := handleLChmod(hdr, path, hdrInfo); err != nil {
return err
}
return chtimes(path, boundTime(latestTime(hdr.AccessTime, hdr.ModTime)), boundTime(hdr.ModTime))
}
func copyBuffered(ctx context.Context, dst io.Writer, src io.Reader) (written int64, err error) {
buf := bufferPool.Get().(*[]byte)
defer bufferPool.Put(buf)

4
archive/tar_opts.go Normal file
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@ -0,0 +1,4 @@
package archive
// ApplyOpt allows setting mutable archive apply properties on creation
type ApplyOpt func(options *ApplyOptions) error

7
archive/tar_opts_unix.go Normal file
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@ -0,0 +1,7 @@
// +build !windows
package archive
// ApplyOptions provides additional options for an Apply operation
type ApplyOptions struct {
}

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@ -0,0 +1,28 @@
// +build windows
package archive
// ApplyOptions provides additional options for an Apply operation
type ApplyOptions struct {
ParentLayerPaths []string // Parent layer paths used for Windows layer apply
IsWindowsContainerLayer bool // True if the tar stream to be applied is a Windows Container Layer
}
// WithParentLayers adds parent layers to the apply process this is required
// for all Windows layers except the base layer.
func WithParentLayers(parentPaths []string) ApplyOpt {
return func(options *ApplyOptions) error {
options.ParentLayerPaths = parentPaths
return nil
}
}
// AsWindowsContainerLayer indicates that the tar stream to apply is that of
// a Windows Container Layer. The caller must be holding SeBackupPrivilege and
// SeRestorePrivilege.
func AsWindowsContainerLayer() ApplyOpt {
return func(options *ApplyOptions) error {
options.IsWindowsContainerLayer = true
return nil
}
}

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@ -3,6 +3,7 @@
package archive
import (
"context"
"os"
"sync"
"syscall"
@ -128,3 +129,9 @@ func getxattr(path, attr string) ([]byte, error) {
func setxattr(path, key, value string) error {
return sysx.LSetxattr(path, key, []byte(value), 0)
}
// apply applies a tar stream of an OCI style diff tar.
// See https://github.com/opencontainers/image-spec/blob/master/layer.md#applying-changesets
func apply(ctx context.Context, root string, tr *tar.Reader, options ApplyOptions) (size int64, err error) {
return applyNaive(ctx, root, tr, options)
}

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@ -1,15 +1,55 @@
// +build windows
package archive
import (
"bufio"
"context"
"encoding/base64"
"errors"
"fmt"
"io"
"os"
"path"
"path/filepath"
"strconv"
"strings"
"syscall"
"github.com/Microsoft/go-winio"
"github.com/Microsoft/hcsshim"
"github.com/containerd/containerd/log"
"github.com/containerd/containerd/sys"
"github.com/dmcgowan/go-tar"
)
const (
// MSWINDOWS pax vendor extensions
hdrMSWindowsPrefix = "MSWINDOWS."
hdrFileAttributes = hdrMSWindowsPrefix + "fileattr"
hdrSecurityDescriptor = hdrMSWindowsPrefix + "sd"
hdrRawSecurityDescriptor = hdrMSWindowsPrefix + "rawsd"
hdrMountPoint = hdrMSWindowsPrefix + "mountpoint"
hdrEaPrefix = hdrMSWindowsPrefix + "xattr."
// LIBARCHIVE pax vendor extensions
hdrLibArchivePrefix = "LIBARCHIVE."
hdrCreateTime = hdrLibArchivePrefix + "creationtime"
)
var (
// mutatedFiles is a list of files that are mutated by the import process
// and must be backed up and restored.
mutatedFiles = map[string]string{
"UtilityVM/Files/EFI/Microsoft/Boot/BCD": "bcd.bak",
"UtilityVM/Files/EFI/Microsoft/Boot/BCD.LOG": "bcd.log.bak",
"UtilityVM/Files/EFI/Microsoft/Boot/BCD.LOG1": "bcd.log1.bak",
"UtilityVM/Files/EFI/Microsoft/Boot/BCD.LOG2": "bcd.log2.bak",
}
)
// tarName returns platform-specific filepath
// to canonical posix-style path for tar archival. p is relative
// path.
@ -101,3 +141,286 @@ func setxattr(path, key, value string) error {
// since xattrs should not exist in windows diff archives
return errors.New("xattrs not supported on Windows")
}
// apply applies a tar stream of an OCI style diff tar of a Windows layer.
// See https://github.com/opencontainers/image-spec/blob/master/layer.md#applying-changesets
func apply(ctx context.Context, root string, tr *tar.Reader, options ApplyOptions) (size int64, err error) {
if options.IsWindowsContainerLayer {
return applyWindowsLayer(ctx, root, tr, options)
}
return applyNaive(ctx, root, tr, options)
}
// applyWindowsLayer applies a tar stream of an OCI style diff tar of a Windows layer.
// See https://github.com/opencontainers/image-spec/blob/master/layer.md#applying-changesets
func applyWindowsLayer(ctx context.Context, root string, tr *tar.Reader, options ApplyOptions) (size int64, err error) {
home, id := filepath.Split(root)
info := hcsshim.DriverInfo{
HomeDir: home,
}
w, err := hcsshim.NewLayerWriter(info, id, options.ParentLayerPaths)
if err != nil {
return 0, err
}
defer func() {
if err := w.Close(); err != nil {
log.G(ctx).Errorf("failed to close layer writer: %v", err)
}
}()
buf := bufio.NewWriter(nil)
hdr, nextErr := tr.Next()
// Iterate through the files in the archive.
for {
select {
case <-ctx.Done():
return 0, ctx.Err()
default:
}
if nextErr == io.EOF {
// end of tar archive
break
}
if nextErr != nil {
return 0, nextErr
}
// Note: path is used instead of filepath to prevent OS specific handling
// of the tar path
base := path.Base(hdr.Name)
if strings.HasPrefix(base, whiteoutPrefix) {
dir := path.Dir(hdr.Name)
originalBase := base[len(whiteoutPrefix):]
originalPath := path.Join(dir, originalBase)
if err := w.Remove(filepath.FromSlash(originalPath)); err != nil {
return 0, err
}
hdr, nextErr = tr.Next()
} else if hdr.Typeflag == tar.TypeLink {
err := w.AddLink(filepath.FromSlash(hdr.Name), filepath.FromSlash(hdr.Linkname))
if err != nil {
return 0, err
}
hdr, nextErr = tr.Next()
} else {
name, fileSize, fileInfo, err := fileInfoFromHeader(hdr)
if err != nil {
return 0, err
}
if err := w.Add(filepath.FromSlash(name), fileInfo); err != nil {
return 0, err
}
size += fileSize
hdr, nextErr = tarToBackupStreamWithMutatedFiles(buf, w, tr, hdr, root)
}
}
return
}
// fileInfoFromHeader retrieves basic Win32 file information from a tar header, using the additional metadata written by
// WriteTarFileFromBackupStream.
func fileInfoFromHeader(hdr *tar.Header) (name string, size int64, fileInfo *winio.FileBasicInfo, err error) {
name = hdr.Name
if hdr.Typeflag == tar.TypeReg || hdr.Typeflag == tar.TypeRegA {
size = hdr.Size
}
fileInfo = &winio.FileBasicInfo{
LastAccessTime: syscall.NsecToFiletime(hdr.AccessTime.UnixNano()),
LastWriteTime: syscall.NsecToFiletime(hdr.ModTime.UnixNano()),
ChangeTime: syscall.NsecToFiletime(hdr.ChangeTime.UnixNano()),
// Default CreationTime to ModTime, updated below if MSWINDOWS.createtime exists
CreationTime: syscall.NsecToFiletime(hdr.ModTime.UnixNano()),
}
if attrStr, ok := hdr.PAXRecords[hdrFileAttributes]; ok {
attr, err := strconv.ParseUint(attrStr, 10, 32)
if err != nil {
return "", 0, nil, err
}
fileInfo.FileAttributes = uintptr(attr)
} else {
if hdr.Typeflag == tar.TypeDir {
fileInfo.FileAttributes |= syscall.FILE_ATTRIBUTE_DIRECTORY
}
}
if createStr, ok := hdr.PAXRecords[hdrCreateTime]; ok {
createTime, err := parsePAXTime(createStr)
if err != nil {
return "", 0, nil, err
}
fileInfo.CreationTime = syscall.NsecToFiletime(createTime.UnixNano())
}
return
}
// tarToBackupStreamWithMutatedFiles reads data from a tar stream and
// writes it to a backup stream, and also saves any files that will be mutated
// by the import layer process to a backup location.
func tarToBackupStreamWithMutatedFiles(buf *bufio.Writer, w io.Writer, t *tar.Reader, hdr *tar.Header, root string) (nextHdr *tar.Header, err error) {
var (
bcdBackup *os.File
bcdBackupWriter *winio.BackupFileWriter
)
if backupPath, ok := mutatedFiles[hdr.Name]; ok {
bcdBackup, err = os.Create(filepath.Join(root, backupPath))
if err != nil {
return nil, err
}
defer func() {
cerr := bcdBackup.Close()
if err == nil {
err = cerr
}
}()
bcdBackupWriter = winio.NewBackupFileWriter(bcdBackup, false)
defer func() {
cerr := bcdBackupWriter.Close()
if err == nil {
err = cerr
}
}()
buf.Reset(io.MultiWriter(w, bcdBackupWriter))
} else {
buf.Reset(w)
}
defer func() {
ferr := buf.Flush()
if err == nil {
err = ferr
}
}()
return writeBackupStreamFromTarFile(buf, t, hdr)
}
// writeBackupStreamFromTarFile writes a Win32 backup stream from the current tar file. Since this function may process multiple
// tar file entries in order to collect all the alternate data streams for the file, it returns the next
// tar file that was not processed, or io.EOF is there are no more.
func writeBackupStreamFromTarFile(w io.Writer, t *tar.Reader, hdr *tar.Header) (*tar.Header, error) {
bw := winio.NewBackupStreamWriter(w)
var sd []byte
var err error
// Maintaining old SDDL-based behavior for backward compatibility. All new tar headers written
// by this library will have raw binary for the security descriptor.
if sddl, ok := hdr.PAXRecords[hdrSecurityDescriptor]; ok {
sd, err = winio.SddlToSecurityDescriptor(sddl)
if err != nil {
return nil, err
}
}
if sdraw, ok := hdr.PAXRecords[hdrRawSecurityDescriptor]; ok {
sd, err = base64.StdEncoding.DecodeString(sdraw)
if err != nil {
return nil, err
}
}
if len(sd) != 0 {
bhdr := winio.BackupHeader{
Id: winio.BackupSecurity,
Size: int64(len(sd)),
}
err := bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = bw.Write(sd)
if err != nil {
return nil, err
}
}
var eas []winio.ExtendedAttribute
for k, v := range hdr.PAXRecords {
if !strings.HasPrefix(k, hdrEaPrefix) {
continue
}
data, err := base64.StdEncoding.DecodeString(v)
if err != nil {
return nil, err
}
eas = append(eas, winio.ExtendedAttribute{
Name: k[len(hdrEaPrefix):],
Value: data,
})
}
if len(eas) != 0 {
eadata, err := winio.EncodeExtendedAttributes(eas)
if err != nil {
return nil, err
}
bhdr := winio.BackupHeader{
Id: winio.BackupEaData,
Size: int64(len(eadata)),
}
err = bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = bw.Write(eadata)
if err != nil {
return nil, err
}
}
if hdr.Typeflag == tar.TypeSymlink {
_, isMountPoint := hdr.PAXRecords[hdrMountPoint]
rp := winio.ReparsePoint{
Target: filepath.FromSlash(hdr.Linkname),
IsMountPoint: isMountPoint,
}
reparse := winio.EncodeReparsePoint(&rp)
bhdr := winio.BackupHeader{
Id: winio.BackupReparseData,
Size: int64(len(reparse)),
}
err := bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = bw.Write(reparse)
if err != nil {
return nil, err
}
}
if hdr.Typeflag == tar.TypeReg || hdr.Typeflag == tar.TypeRegA {
bhdr := winio.BackupHeader{
Id: winio.BackupData,
Size: hdr.Size,
}
err := bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = io.Copy(bw, t)
if err != nil {
return nil, err
}
}
// Copy all the alternate data streams and return the next non-ADS header.
for {
ahdr, err := t.Next()
if err != nil {
return nil, err
}
if ahdr.Typeflag != tar.TypeReg || !strings.HasPrefix(ahdr.Name, hdr.Name+":") {
return ahdr, nil
}
bhdr := winio.BackupHeader{
Id: winio.BackupAlternateData,
Size: ahdr.Size,
Name: ahdr.Name[len(hdr.Name):] + ":$DATA",
}
err = bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = io.Copy(bw, t)
if err != nil {
return nil, err
}
}
}

View File

@ -34,7 +34,7 @@ github.com/containerd/continuity cf279e6ac893682272b4479d4c67fd3abf878b4e
golang.org/x/sync 450f422ab23cf9881c94e2db30cac0eb1b7cf80c
github.com/BurntSushi/toml v0.2.0-21-g9906417
github.com/grpc-ecosystem/go-grpc-prometheus 6b7015e65d366bf3f19b2b2a000a831940f0f7e0
github.com/Microsoft/go-winio v0.4.4
github.com/Microsoft/go-winio v0.4.5
github.com/Microsoft/hcsshim v0.6.7
github.com/boltdb/bolt e9cf4fae01b5a8ff89d0ec6b32f0d9c9f79aefdd
google.golang.org/genproto d80a6e20e776b0b17a324d0ba1ab50a39c8e8944

View File

@ -68,10 +68,20 @@ func NewBackupStreamReader(r io.Reader) *BackupStreamReader {
return &BackupStreamReader{r, 0}
}
// Next returns the next backup stream and prepares for calls to Write(). It skips the remainder of the current stream if
// Next returns the next backup stream and prepares for calls to Read(). It skips the remainder of the current stream if
// it was not completely read.
func (r *BackupStreamReader) Next() (*BackupHeader, error) {
if r.bytesLeft > 0 {
if s, ok := r.r.(io.Seeker); ok {
// Make sure Seek on io.SeekCurrent sometimes succeeds
// before trying the actual seek.
if _, err := s.Seek(0, io.SeekCurrent); err == nil {
if _, err = s.Seek(r.bytesLeft, io.SeekCurrent); err != nil {
return nil, err
}
r.bytesLeft = 0
}
}
if _, err := io.Copy(ioutil.Discard, r); err != nil {
return nil, err
}
@ -220,7 +230,7 @@ type BackupFileWriter struct {
ctx uintptr
}
// NewBackupFileWrtier returns a new BackupFileWriter from a file handle. If includeSecurity is true,
// NewBackupFileWriter returns a new BackupFileWriter from a file handle. If includeSecurity is true,
// Write() will attempt to restore the security descriptor from the stream.
func NewBackupFileWriter(f *os.File, includeSecurity bool) *BackupFileWriter {
w := &BackupFileWriter{f, includeSecurity, 0}

137
vendor/github.com/Microsoft/go-winio/ea.go generated vendored Normal file
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@ -0,0 +1,137 @@
package winio
import (
"bytes"
"encoding/binary"
"errors"
)
type fileFullEaInformation struct {
NextEntryOffset uint32
Flags uint8
NameLength uint8
ValueLength uint16
}
var (
fileFullEaInformationSize = binary.Size(&fileFullEaInformation{})
errInvalidEaBuffer = errors.New("invalid extended attribute buffer")
errEaNameTooLarge = errors.New("extended attribute name too large")
errEaValueTooLarge = errors.New("extended attribute value too large")
)
// ExtendedAttribute represents a single Windows EA.
type ExtendedAttribute struct {
Name string
Value []byte
Flags uint8
}
func parseEa(b []byte) (ea ExtendedAttribute, nb []byte, err error) {
var info fileFullEaInformation
err = binary.Read(bytes.NewReader(b), binary.LittleEndian, &info)
if err != nil {
err = errInvalidEaBuffer
return
}
nameOffset := fileFullEaInformationSize
nameLen := int(info.NameLength)
valueOffset := nameOffset + int(info.NameLength) + 1
valueLen := int(info.ValueLength)
nextOffset := int(info.NextEntryOffset)
if valueLen+valueOffset > len(b) || nextOffset < 0 || nextOffset > len(b) {
err = errInvalidEaBuffer
return
}
ea.Name = string(b[nameOffset : nameOffset+nameLen])
ea.Value = b[valueOffset : valueOffset+valueLen]
ea.Flags = info.Flags
if info.NextEntryOffset != 0 {
nb = b[info.NextEntryOffset:]
}
return
}
// DecodeExtendedAttributes decodes a list of EAs from a FILE_FULL_EA_INFORMATION
// buffer retrieved from BackupRead, ZwQueryEaFile, etc.
func DecodeExtendedAttributes(b []byte) (eas []ExtendedAttribute, err error) {
for len(b) != 0 {
ea, nb, err := parseEa(b)
if err != nil {
return nil, err
}
eas = append(eas, ea)
b = nb
}
return
}
func writeEa(buf *bytes.Buffer, ea *ExtendedAttribute, last bool) error {
if int(uint8(len(ea.Name))) != len(ea.Name) {
return errEaNameTooLarge
}
if int(uint16(len(ea.Value))) != len(ea.Value) {
return errEaValueTooLarge
}
entrySize := uint32(fileFullEaInformationSize + len(ea.Name) + 1 + len(ea.Value))
withPadding := (entrySize + 3) &^ 3
nextOffset := uint32(0)
if !last {
nextOffset = withPadding
}
info := fileFullEaInformation{
NextEntryOffset: nextOffset,
Flags: ea.Flags,
NameLength: uint8(len(ea.Name)),
ValueLength: uint16(len(ea.Value)),
}
err := binary.Write(buf, binary.LittleEndian, &info)
if err != nil {
return err
}
_, err = buf.Write([]byte(ea.Name))
if err != nil {
return err
}
err = buf.WriteByte(0)
if err != nil {
return err
}
_, err = buf.Write(ea.Value)
if err != nil {
return err
}
_, err = buf.Write([]byte{0, 0, 0}[0 : withPadding-entrySize])
if err != nil {
return err
}
return nil
}
// EncodeExtendedAttributes encodes a list of EAs into a FILE_FULL_EA_INFORMATION
// buffer for use with BackupWrite, ZwSetEaFile, etc.
func EncodeExtendedAttributes(eas []ExtendedAttribute) ([]byte, error) {
var buf bytes.Buffer
for i := range eas {
last := false
if i == len(eas)-1 {
last = true
}
err := writeEa(&buf, &eas[i], last)
if err != nil {
return nil, err
}
}
return buf.Bytes(), nil
}

View File

@ -78,6 +78,7 @@ func initIo() {
type win32File struct {
handle syscall.Handle
wg sync.WaitGroup
wgLock sync.RWMutex
closing atomicBool
readDeadline deadlineHandler
writeDeadline deadlineHandler
@ -114,14 +115,18 @@ func MakeOpenFile(h syscall.Handle) (io.ReadWriteCloser, error) {
// closeHandle closes the resources associated with a Win32 handle
func (f *win32File) closeHandle() {
f.wgLock.Lock()
// Atomically set that we are closing, releasing the resources only once.
if !f.closing.swap(true) {
f.wgLock.Unlock()
// cancel all IO and wait for it to complete
cancelIoEx(f.handle, nil)
f.wg.Wait()
// at this point, no new IO can start
syscall.Close(f.handle)
f.handle = 0
} else {
f.wgLock.Unlock()
}
}
@ -134,10 +139,13 @@ func (f *win32File) Close() error {
// prepareIo prepares for a new IO operation.
// The caller must call f.wg.Done() when the IO is finished, prior to Close() returning.
func (f *win32File) prepareIo() (*ioOperation, error) {
f.wgLock.RLock()
if f.closing.isSet() {
f.wgLock.RUnlock()
return nil, ErrFileClosed
}
f.wg.Add(1)
f.wgLock.RUnlock()
c := &ioOperation{}
c.ch = make(chan ioResult)
return c, nil

View File

@ -265,9 +265,9 @@ func (l *win32PipeListener) listenerRoutine() {
if err == nil {
// Wait for the client to connect.
ch := make(chan error)
go func() {
go func(p *win32File) {
ch <- connectPipe(p)
}()
}(p)
select {
case err = <-ch:
if err != nil {