Migrate to containerd 1.54

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

vendor/github.com/containerd/continuity/AUTHORS

@@ -1,16 +1,40 @@
 Aaron Lehmann <aaron.lehmann@docker.com>
 Akash Gupta <akagup@microsoft.com>
+Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
 Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
+Akihiro Suda <suda.kyoto@gmail.com>
 Andrew Pennebaker <apennebaker@datapipe.com>
 Brandon Philips <brandon.philips@coreos.com>
+Brian Goff <cpuguy83@gmail.com>
 Christopher Jones <tophj@linux.vnet.ibm.com>
 Daniel, Dao Quang Minh <dqminh89@gmail.com>
+Darren Stahl <darst@microsoft.com>
+Derek McGowan <derek@mcg.dev>
 Derek McGowan <derek@mcgstyle.net>
 Edward Pilatowicz <edward.pilatowicz@oracle.com>
 Ian Campbell <ijc@docker.com>
+Ivan Markin <sw@nogoegst.net>
 Justin Cormack <justin.cormack@docker.com>
 Justin Cummins <sul3n3t@gmail.com>
+Kasper Fabæch Brandt <poizan@poizan.dk>
+Kir Kolyshkin <kolyshkin@gmail.com>
+Michael Crosby <crosbymichael@gmail.com>
+Michael Crosby <michael@thepasture.io>
+Michael Wan <zirenwan@gmail.com>
+Mike Brown <brownwm@us.ibm.com>
+Niels de Vos <ndevos@redhat.com>
 Phil Estes <estesp@gmail.com>
+Phil Estes <estesp@linux.vnet.ibm.com>
+Samuel Karp <me@samuelkarp.com>
+Sam Whited <sam@samwhited.com>
+Sebastiaan van Stijn <github@gone.nl>
+Shengjing Zhu <zhsj@debian.org>
 Stephen J Day <stephen.day@docker.com>
+Tibor Vass <tibor@docker.com>
 Tobias Klauser <tklauser@distanz.ch>
+Tom Faulhaber <tffaulha@amazon.com>
 Tonis Tiigi <tonistiigi@gmail.com>
+Trevor Porter <trkporter@ucdavis.edu>
+Wei Fu <fuweid89@gmail.com>
+Wilbert van de Ridder <wilbert.ridder@gmail.com>
+Xiaodong Ye <xiaodongy@vmware.com>

vendor/github.com/containerd/continuity/fs/copy.go

@@ -39,6 +39,8 @@ type XAttrErrorHandler func(dst, src, xattrKey string, err error) error
 
 type copyDirOpts struct {
 	xeh XAttrErrorHandler
+	// xex contains a set of xattrs to exclude when copying
+	xex map[string]struct{}
 }
 
 type CopyDirOpt func(*copyDirOpts) error
@@ -61,6 +63,19 @@ func WithAllowXAttrErrors() CopyDirOpt {
 	return WithXAttrErrorHandler(xeh)
 }
 
+// WithXAttrExclude allows for exclusion of specified xattr during CopyDir operation.
+func WithXAttrExclude(keys ...string) CopyDirOpt {
+	return func(o *copyDirOpts) error {
+		if o.xex == nil {
+			o.xex = make(map[string]struct{}, len(keys))
+		}
+		for _, key := range keys {
+			o.xex[key] = struct{}{}
+		}
+		return nil
+	}
+}
+
 // CopyDir copies the directory from src to dst.
 // Most efficient copy of files is attempted.
 func CopyDir(dst, src string, opts ...CopyDirOpt) error {
@@ -80,7 +95,7 @@ func copyDirectory(dst, src string, inodes map[uint64]string, o *copyDirOpts) er
 		return errors.Wrapf(err, "failed to stat %s", src)
 	}
 	if !stat.IsDir() {
-		return errors.Errorf("source is not directory")
+		return errors.Errorf("source %s is not directory", src)
 	}
 
 	if st, err := os.Stat(dst); err != nil {
@@ -104,6 +119,10 @@ func copyDirectory(dst, src string, inodes map[uint64]string, o *copyDirOpts) er
 		return errors.Wrapf(err, "failed to copy file info for %s", dst)
 	}
 
+	if err := copyXAttrs(dst, src, o.xex, o.xeh); err != nil {
+		return errors.Wrap(err, "failed to copy xattrs")
+	}
+
 	for _, fi := range fis {
 		source := filepath.Join(src, fi.Name())
 		target := filepath.Join(dst, fi.Name())
@@ -146,7 +165,7 @@ func copyDirectory(dst, src string, inodes map[uint64]string, o *copyDirOpts) er
 			return errors.Wrap(err, "failed to copy file info")
 		}
 
-		if err := copyXAttrs(target, source, o.xeh); err != nil {
+		if err := copyXAttrs(target, source, o.xex, o.xeh); err != nil {
 			return errors.Wrap(err, "failed to copy xattrs")
 		}
 	}

vendor/github.com/containerd/continuity/fs/copy_darwinopenbsdsolaris.go

@@ -1,4 +1,4 @@
-// +build !windows
+// +build darwin openbsd solaris
 
 /*
    Copyright The containerd Authors.
@@ -16,11 +16,25 @@
    limitations under the License.
 */
 
-package syscallx
+package fs
 
-import "syscall"
+import (
+	"os"
+	"syscall"
 
-// Readlink returns the destination of the named symbolic link.
-func Readlink(path string, buf []byte) (n int, err error) {
-	return syscall.Readlink(path, buf)
+	"github.com/pkg/errors"
+	"golang.org/x/sys/unix"
+)
+
+func copyDevice(dst string, fi os.FileInfo) error {
+	st, ok := fi.Sys().(*syscall.Stat_t)
+	if !ok {
+		return errors.New("unsupported stat type")
+	}
+	return unix.Mknod(dst, uint32(fi.Mode()), int(st.Rdev))
+}
+
+func utimesNano(name string, atime, mtime syscall.Timespec) error {
+	timespec := []syscall.Timespec{atime, mtime}
+	return syscall.UtimesNano(name, timespec)
 }

vendor/github.com/containerd/continuity/fs/copy_freebsd.go

@@ -0,0 +1,42 @@
+// +build freebsd
+
+/*
+   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.
+*/
+
+package fs
+
+import (
+	"os"
+	"syscall"
+
+	"github.com/pkg/errors"
+	"golang.org/x/sys/unix"
+)
+
+func copyDevice(dst string, fi os.FileInfo) error {
+	st, ok := fi.Sys().(*syscall.Stat_t)
+	if !ok {
+		return errors.New("unsupported stat type")
+	}
+	return unix.Mknod(dst, uint32(fi.Mode()), st.Rdev)
+}
+
+func utimesNano(name string, atime, mtime syscall.Timespec) error {
+	at := unix.NsecToTimespec(atime.Nano())
+	mt := unix.NsecToTimespec(mtime.Nano())
+	utimes := [2]unix.Timespec{at, mt}
+	return unix.UtimesNanoAt(unix.AT_FDCWD, name, utimes[0:], unix.AT_SYMLINK_NOFOLLOW)
+}

vendor/github.com/containerd/continuity/fs/copy_linux.go

@@ -51,7 +51,10 @@ func copyFileInfo(fi os.FileInfo, name string) error {
 		}
 	}
 
-	timespec := []unix.Timespec{unix.Timespec(StatAtime(st)), unix.Timespec(StatMtime(st))}
+	timespec := []unix.Timespec{
+		unix.NsecToTimespec(syscall.TimespecToNsec(StatAtime(st))),
+		unix.NsecToTimespec(syscall.TimespecToNsec(StatMtime(st))),
+	}
 	if err := unix.UtimesNanoAt(unix.AT_FDCWD, name, timespec, unix.AT_SYMLINK_NOFOLLOW); err != nil {
 		return errors.Wrapf(err, "failed to utime %s", name)
 	}
@@ -101,21 +104,24 @@ func copyFileContent(dst, src *os.File) error {
 	return nil
 }
 
-func copyXAttrs(dst, src string, xeh XAttrErrorHandler) error {
+func copyXAttrs(dst, src string, excludes map[string]struct{}, errorHandler XAttrErrorHandler) error {
 	xattrKeys, err := sysx.LListxattr(src)
 	if err != nil {
 		e := errors.Wrapf(err, "failed to list xattrs on %s", src)
-		if xeh != nil {
-			e = xeh(dst, src, "", e)
+		if errorHandler != nil {
+			e = errorHandler(dst, src, "", e)
 		}
 		return e
 	}
 	for _, xattr := range xattrKeys {
+		if _, exclude := excludes[xattr]; exclude {
+			continue
+		}
 		data, err := sysx.LGetxattr(src, xattr)
 		if err != nil {
 			e := errors.Wrapf(err, "failed to get xattr %q on %s", xattr, src)
-			if xeh != nil {
-				if e = xeh(dst, src, xattr, e); e == nil {
+			if errorHandler != nil {
+				if e = errorHandler(dst, src, xattr, e); e == nil {
 					continue
 				}
 			}
@@ -123,8 +129,8 @@ func copyXAttrs(dst, src string, xeh XAttrErrorHandler) error {
 		}
 		if err := sysx.LSetxattr(dst, xattr, data, 0); err != nil {
 			e := errors.Wrapf(err, "failed to set xattr %q on %s", xattr, dst)
-			if xeh != nil {
-				if e = xeh(dst, src, xattr, e); e == nil {
+			if errorHandler != nil {
+				if e = errorHandler(dst, src, xattr, e); e == nil {
 					continue
 				}
 			}

vendor/github.com/containerd/continuity/fs/copy_unix.go

@@ -1,4 +1,4 @@
-// +build solaris darwin freebsd
+// +build darwin freebsd openbsd solaris
 
 /*
    Copyright The containerd Authors.
@@ -25,7 +25,6 @@ import (
 
 	"github.com/containerd/continuity/sysx"
 	"github.com/pkg/errors"
-	"golang.org/x/sys/unix"
 )
 
 func copyFileInfo(fi os.FileInfo, name string) error {
@@ -53,8 +52,7 @@ func copyFileInfo(fi os.FileInfo, name string) error {
 		}
 	}
 
-	timespec := []syscall.Timespec{StatAtime(st), StatMtime(st)}
-	if err := syscall.UtimesNano(name, timespec); err != nil {
+	if err := utimesNano(name, StatAtime(st), StatMtime(st)); err != nil {
 		return errors.Wrapf(err, "failed to utime %s", name)
 	}
 
@@ -69,21 +67,24 @@ func copyFileContent(dst, src *os.File) error {
 	return err
 }
 
-func copyXAttrs(dst, src string, xeh XAttrErrorHandler) error {
+func copyXAttrs(dst, src string, excludes map[string]struct{}, errorHandler XAttrErrorHandler) error {
 	xattrKeys, err := sysx.LListxattr(src)
 	if err != nil {
 		e := errors.Wrapf(err, "failed to list xattrs on %s", src)
-		if xeh != nil {
-			e = xeh(dst, src, "", e)
+		if errorHandler != nil {
+			e = errorHandler(dst, src, "", e)
 		}
 		return e
 	}
 	for _, xattr := range xattrKeys {
+		if _, exclude := excludes[xattr]; exclude {
+			continue
+		}
 		data, err := sysx.LGetxattr(src, xattr)
 		if err != nil {
 			e := errors.Wrapf(err, "failed to get xattr %q on %s", xattr, src)
-			if xeh != nil {
-				if e = xeh(dst, src, xattr, e); e == nil {
+			if errorHandler != nil {
+				if e = errorHandler(dst, src, xattr, e); e == nil {
 					continue
 				}
 			}
@@ -91,8 +92,8 @@ func copyXAttrs(dst, src string, xeh XAttrErrorHandler) error {
 		}
 		if err := sysx.LSetxattr(dst, xattr, data, 0); err != nil {
 			e := errors.Wrapf(err, "failed to set xattr %q on %s", xattr, dst)
-			if xeh != nil {
-				if e = xeh(dst, src, xattr, e); e == nil {
+			if errorHandler != nil {
+				if e = errorHandler(dst, src, xattr, e); e == nil {
 					continue
 				}
 			}
@@ -102,11 +103,3 @@ func copyXAttrs(dst, src string, xeh XAttrErrorHandler) error {
 
 	return nil
 }
-
-func copyDevice(dst string, fi os.FileInfo) error {
-	st, ok := fi.Sys().(*syscall.Stat_t)
-	if !ok {
-		return errors.New("unsupported stat type")
-	}
-	return unix.Mknod(dst, uint32(fi.Mode()), int(st.Rdev))
-}

vendor/github.com/containerd/continuity/fs/copy_windows.go

@@ -40,7 +40,7 @@ func copyFileContent(dst, src *os.File) error {
 	return err
 }
 
-func copyXAttrs(dst, src string, xeh XAttrErrorHandler) error {
+func copyXAttrs(dst, src string, excludes map[string]struct{}, errorHandler XAttrErrorHandler) error {
 	return nil
 }
 

vendor/github.com/containerd/continuity/fs/du_unix.go

@@ -25,6 +25,14 @@ import (
 	"syscall"
 )
 
+// blocksUnitSize is the unit used by `st_blocks` in `stat` in bytes.
+// See https://man7.org/linux/man-pages/man2/stat.2.html
+//   st_blocks
+//     This field indicates the number of blocks allocated to the
+//     file, in 512-byte units.  (This may be smaller than
+//     st_size/512 when the file has holes.)
+const blocksUnitSize = 512
+
 type inode struct {
 	// TODO(stevvooe): Can probably reduce memory usage by not tracking
 	// device, but we can leave this right for now.
@@ -33,9 +41,9 @@ type inode struct {
 
 func newInode(stat *syscall.Stat_t) inode {
 	return inode{
-		// Dev is uint32 on darwin/bsd, uint64 on linux/solaris
+		// Dev is uint32 on darwin/bsd, uint64 on linux/solaris/freebsd
 		dev: uint64(stat.Dev), // nolint: unconvert
-		// Ino is uint32 on bsd, uint64 on darwin/linux/solaris
+		// Ino is uint32 on bsd, uint64 on darwin/linux/solaris/freebsd
 		ino: uint64(stat.Ino), // nolint: unconvert
 	}
 }
@@ -59,10 +67,11 @@ func diskUsage(ctx context.Context, roots ...string) (Usage, error) {
 			default:
 			}
 
-			inoKey := newInode(fi.Sys().(*syscall.Stat_t))
+			stat := fi.Sys().(*syscall.Stat_t)
+			inoKey := newInode(stat)
 			if _, ok := inodes[inoKey]; !ok {
 				inodes[inoKey] = struct{}{}
-				size += fi.Size()
+				size += stat.Blocks * blocksUnitSize
 			}
 
 			return nil
@@ -89,10 +98,11 @@ func diffUsage(ctx context.Context, a, b string) (Usage, error) {
 		}
 
 		if kind == ChangeKindAdd || kind == ChangeKindModify {
-			inoKey := newInode(fi.Sys().(*syscall.Stat_t))
+			stat := fi.Sys().(*syscall.Stat_t)
+			inoKey := newInode(stat)
 			if _, ok := inodes[inoKey]; !ok {
 				inodes[inoKey] = struct{}{}
-				size += fi.Size()
+				size += stat.Blocks * blocksUnitSize
 			}
 
 			return nil

vendor/github.com/containerd/continuity/fs/path.go

@@ -117,15 +117,13 @@ func sameFile(f1, f2 *currentPath) (bool, error) {
 		// If the timestamp may have been truncated in both of the
 		// files, check content of file to determine difference
 		if t1.Nanosecond() == 0 && t2.Nanosecond() == 0 {
-			var eq bool
 			if (f1.f.Mode() & os.ModeSymlink) == os.ModeSymlink {
-				eq, err = compareSymlinkTarget(f1.fullPath, f2.fullPath)
-			} else if f1.f.Size() > 0 {
-				eq, err = compareFileContent(f1.fullPath, f2.fullPath)
+				return compareSymlinkTarget(f1.fullPath, f2.fullPath)
 			}
-			if err != nil || !eq {
-				return eq, err
+			if f1.f.Size() == 0 { // if file sizes are zero length, the files are the same by definition
+				return true, nil
 			}
+			return compareFileContent(f1.fullPath, f2.fullPath)
 		} else if t1.Nanosecond() != t2.Nanosecond() {
 			return false, nil
 		}

vendor/github.com/containerd/continuity/fs/stat_linuxopenbsd.go

@@ -1,3 +1,5 @@
+// +build linux openbsd
+
 /*
    Copyright The containerd Authors.
 

vendor/github.com/containerd/continuity/syscallx/syscall_windows.go

@@ -1,112 +0,0 @@
-/*
-   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.
-*/
-
-package syscallx
-
-import (
-	"syscall"
-	"unsafe"
-)
-
-type reparseDataBuffer struct {
-	ReparseTag        uint32
-	ReparseDataLength uint16
-	Reserved          uint16
-
-	// GenericReparseBuffer
-	reparseBuffer byte
-}
-
-type mountPointReparseBuffer struct {
-	SubstituteNameOffset uint16
-	SubstituteNameLength uint16
-	PrintNameOffset      uint16
-	PrintNameLength      uint16
-	PathBuffer           [1]uint16
-}
-
-type symbolicLinkReparseBuffer struct {
-	SubstituteNameOffset uint16
-	SubstituteNameLength uint16
-	PrintNameOffset      uint16
-	PrintNameLength      uint16
-	Flags                uint32
-	PathBuffer           [1]uint16
-}
-
-const (
-	_IO_REPARSE_TAG_MOUNT_POINT = 0xA0000003
-	_SYMLINK_FLAG_RELATIVE      = 1
-)
-
-// Readlink returns the destination of the named symbolic link.
-func Readlink(path string, buf []byte) (n int, err error) {
-	fd, err := syscall.CreateFile(syscall.StringToUTF16Ptr(path), syscall.GENERIC_READ, 0, nil, syscall.OPEN_EXISTING,
-		syscall.FILE_FLAG_OPEN_REPARSE_POINT|syscall.FILE_FLAG_BACKUP_SEMANTICS, 0)
-	if err != nil {
-		return -1, err
-	}
-	defer syscall.CloseHandle(fd)
-
-	rdbbuf := make([]byte, syscall.MAXIMUM_REPARSE_DATA_BUFFER_SIZE)
-	var bytesReturned uint32
-	err = syscall.DeviceIoControl(fd, syscall.FSCTL_GET_REPARSE_POINT, nil, 0, &rdbbuf[0], uint32(len(rdbbuf)), &bytesReturned, nil)
-	if err != nil {
-		return -1, err
-	}
-
-	rdb := (*reparseDataBuffer)(unsafe.Pointer(&rdbbuf[0]))
-	var s string
-	switch rdb.ReparseTag {
-	case syscall.IO_REPARSE_TAG_SYMLINK:
-		data := (*symbolicLinkReparseBuffer)(unsafe.Pointer(&rdb.reparseBuffer))
-		p := (*[0xffff]uint16)(unsafe.Pointer(&data.PathBuffer[0]))
-		s = syscall.UTF16ToString(p[data.SubstituteNameOffset/2 : (data.SubstituteNameOffset+data.SubstituteNameLength)/2])
-		if data.Flags&_SYMLINK_FLAG_RELATIVE == 0 {
-			if len(s) >= 4 && s[:4] == `\??\` {
-				s = s[4:]
-				switch {
-				case len(s) >= 2 && s[1] == ':': // \??\C:\foo\bar
-					// do nothing
-				case len(s) >= 4 && s[:4] == `UNC\`: // \??\UNC\foo\bar
-					s = `\\` + s[4:]
-				default:
-					// unexpected; do nothing
-				}
-			} else {
-				// unexpected; do nothing
-			}
-		}
-	case _IO_REPARSE_TAG_MOUNT_POINT:
-		data := (*mountPointReparseBuffer)(unsafe.Pointer(&rdb.reparseBuffer))
-		p := (*[0xffff]uint16)(unsafe.Pointer(&data.PathBuffer[0]))
-		s = syscall.UTF16ToString(p[data.SubstituteNameOffset/2 : (data.SubstituteNameOffset+data.SubstituteNameLength)/2])
-		if len(s) >= 4 && s[:4] == `\??\` { // \??\C:\foo\bar
-			if len(s) < 48 || s[:11] != `\??\Volume{` {
-				s = s[4:]
-			}
-		} else {
-			// unexpected; do nothing
-		}
-	default:
-		// the path is not a symlink or junction but another type of reparse
-		// point
-		return -1, syscall.ENOENT
-	}
-	n = copy(buf, []byte(s))
-
-	return n, nil
-}

vendor/github.com/containerd/continuity/sysx/file_posix.go

@@ -1,128 +0,0 @@
-/*
-   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.
-*/
-
-package sysx
-
-import (
-	"os"
-	"path/filepath"
-
-	"github.com/containerd/continuity/syscallx"
-)
-
-// Readlink returns the destination of the named symbolic link.
-// If there is an error, it will be of type *PathError.
-func Readlink(name string) (string, error) {
-	for len := 128; ; len *= 2 {
-		b := make([]byte, len)
-		n, e := fixCount(syscallx.Readlink(fixLongPath(name), b))
-		if e != nil {
-			return "", &os.PathError{Op: "readlink", Path: name, Err: e}
-		}
-		if n < len {
-			return string(b[0:n]), nil
-		}
-	}
-}
-
-// Many functions in package syscall return a count of -1 instead of 0.
-// Using fixCount(call()) instead of call() corrects the count.
-func fixCount(n int, err error) (int, error) {
-	if n < 0 {
-		n = 0
-	}
-	return n, err
-}
-
-// fixLongPath returns the extended-length (\\?\-prefixed) form of
-// path when needed, in order to avoid the default 260 character file
-// path limit imposed by Windows. If path is not easily converted to
-// the extended-length form (for example, if path is a relative path
-// or contains .. elements), or is short enough, fixLongPath returns
-// path unmodified.
-//
-// See https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx#maxpath
-func fixLongPath(path string) string {
-	// Do nothing (and don't allocate) if the path is "short".
-	// Empirically (at least on the Windows Server 2013 builder),
-	// the kernel is arbitrarily okay with < 248 bytes. That
-	// matches what the docs above say:
-	// "When using an API to create a directory, the specified
-	// path cannot be so long that you cannot append an 8.3 file
-	// name (that is, the directory name cannot exceed MAX_PATH
-	// minus 12)." Since MAX_PATH is 260, 260 - 12 = 248.
-	//
-	// The MSDN docs appear to say that a normal path that is 248 bytes long
-	// will work; empirically the path must be less then 248 bytes long.
-	if len(path) < 248 {
-		// Don't fix. (This is how Go 1.7 and earlier worked,
-		// not automatically generating the \\?\ form)
-		return path
-	}
-
-	// The extended form begins with \\?\, as in
-	// \\?\c:\windows\foo.txt or \\?\UNC\server\share\foo.txt.
-	// The extended form disables evaluation of . and .. path
-	// elements and disables the interpretation of / as equivalent
-	// to \. The conversion here rewrites / to \ and elides
-	// . elements as well as trailing or duplicate separators. For
-	// simplicity it avoids the conversion entirely for relative
-	// paths or paths containing .. elements. For now,
-	// \\server\share paths are not converted to
-	// \\?\UNC\server\share paths because the rules for doing so
-	// are less well-specified.
-	if len(path) >= 2 && path[:2] == `\\` {
-		// Don't canonicalize UNC paths.
-		return path
-	}
-	if !filepath.IsAbs(path) {
-		// Relative path
-		return path
-	}
-
-	const prefix = `\\?`
-
-	pathbuf := make([]byte, len(prefix)+len(path)+len(`\`))
-	copy(pathbuf, prefix)
-	n := len(path)
-	r, w := 0, len(prefix)
-	for r < n {
-		switch {
-		case os.IsPathSeparator(path[r]):
-			// empty block
-			r++
-		case path[r] == '.' && (r+1 == n || os.IsPathSeparator(path[r+1])):
-			// /./
-			r++
-		case r+1 < n && path[r] == '.' && path[r+1] == '.' && (r+2 == n || os.IsPathSeparator(path[r+2])):
-			// /../ is currently unhandled
-			return path
-		default:
-			pathbuf[w] = '\\'
-			w++
-			for ; r < n && !os.IsPathSeparator(path[r]); r++ {
-				pathbuf[w] = path[r]
-				w++
-			}
-		}
-	}
-	// A drive's root directory needs a trailing \
-	if w == len(`\\?\c:`) {
-		pathbuf[w] = '\\'
-		w++
-	}
-	return string(pathbuf[:w])
-}

vendor/github.com/containerd/continuity/sysx/nodata_unix.go

@@ -1,4 +1,4 @@
-// +build darwin freebsd
+// +build darwin freebsd openbsd
 
 /*
    Copyright The containerd Authors.

vendor/github.com/containerd/continuity/sysx/xattr.go

@@ -20,7 +20,6 @@ package sysx
 
 import (
 	"bytes"
-	"syscall"
 
 	"golang.org/x/sys/unix"
 )
@@ -66,60 +65,53 @@ func LGetxattr(path, attr string) ([]byte, error) {
 	return getxattrAll(path, attr, unix.Lgetxattr)
 }
 
-const defaultXattrBufferSize = 5
+const defaultXattrBufferSize = 128
 
 type listxattrFunc func(path string, dest []byte) (int, error)
 
 func listxattrAll(path string, listFunc listxattrFunc) ([]string, error) {
-	var p []byte // nil on first execution
-
-	for {
-		n, err := listFunc(path, p) // first call gets buffer size.
+	buf := make([]byte, defaultXattrBufferSize)
+	n, err := listFunc(path, buf)
+	for err == unix.ERANGE {
+		// Buffer too small, use zero-sized buffer to get the actual size
+		n, err = listFunc(path, []byte{})
 		if err != nil {
 			return nil, err
 		}
-
-		if n > len(p) {
-			p = make([]byte, n)
-			continue
-		}
-
-		p = p[:n]
-
-		ps := bytes.Split(bytes.TrimSuffix(p, []byte{0}), []byte{0})
-		var entries []string
-		for _, p := range ps {
-			s := string(p)
-			if s != "" {
-				entries = append(entries, s)
-			}
-		}
-
-		return entries, nil
+		buf = make([]byte, n)
+		n, err = listFunc(path, buf)
 	}
+	if err != nil {
+		return nil, err
+	}
+
+	ps := bytes.Split(bytes.TrimSuffix(buf[:n], []byte{0}), []byte{0})
+	var entries []string
+	for _, p := range ps {
+		if len(p) > 0 {
+			entries = append(entries, string(p))
+		}
+	}
+
+	return entries, nil
 }
 
 type getxattrFunc func(string, string, []byte) (int, error)
 
 func getxattrAll(path, attr string, getFunc getxattrFunc) ([]byte, error) {
-	p := make([]byte, defaultXattrBufferSize)
-	for {
-		n, err := getFunc(path, attr, p)
+	buf := make([]byte, defaultXattrBufferSize)
+	n, err := getFunc(path, attr, buf)
+	for err == unix.ERANGE {
+		// Buffer too small, use zero-sized buffer to get the actual size
+		n, err = getFunc(path, attr, []byte{})
 		if err != nil {
-			if errno, ok := err.(syscall.Errno); ok && errno == syscall.ERANGE {
-				p = make([]byte, len(p)*2) // this can't be ideal.
-				continue                   // try again!
-			}
-
 			return nil, err
 		}
-
-		// realloc to correct size and repeat
-		if n > len(p) {
-			p = make([]byte, n)
-			continue
-		}
-
-		return p[:n], nil
+		buf = make([]byte, n)
+		n, err = getFunc(path, attr, buf)
 	}
+	if err != nil {
+		return nil, err
+	}
+	return buf[:n], nil
 }

vendor/github.com/containerd/continuity/sysx/xattr_unsupported.go

@@ -23,7 +23,7 @@ import (
 	"runtime"
 )
 
-var unsupported = errors.New("extended attributes unsupported on " + runtime.GOOS)
+var errUnsupported = errors.New("extended attributes unsupported on " + runtime.GOOS)
 
 // Listxattr calls syscall listxattr and reads all content
 // and returns a string array
@@ -33,17 +33,17 @@ func Listxattr(path string) ([]string, error) {
 
 // Removexattr calls syscall removexattr
 func Removexattr(path string, attr string) (err error) {
-	return unsupported
+	return errUnsupported
 }
 
 // Setxattr calls syscall setxattr
 func Setxattr(path string, attr string, data []byte, flags int) (err error) {
-	return unsupported
+	return errUnsupported
 }
 
 // Getxattr calls syscall getxattr
 func Getxattr(path, attr string) ([]byte, error) {
-	return []byte{}, unsupported
+	return []byte{}, errUnsupported
 }
 
 // LListxattr lists xattrs, not following symlinks
@@ -53,12 +53,12 @@ func LListxattr(path string) ([]string, error) {
 
 // LRemovexattr removes an xattr, not following symlinks
 func LRemovexattr(path string, attr string) (err error) {
-	return unsupported
+	return errUnsupported
 }
 
 // LSetxattr sets an xattr, not following symlinks
 func LSetxattr(path string, attr string, data []byte, flags int) (err error) {
-	return unsupported
+	return errUnsupported
 }
 
 // LGetxattr gets an xattr, not following symlinks