vendor: update containerd/continuity efbc4488d8fe1bdc16bde3b2d2990d9b3a899165

full diff: https://github.com/containerd/continuity/compare/26c1120b8d4107d2471b93ad78ef7ce1fc84c4c4...efbc4488d8fe1bdc16bde3b2d2990d9b3a899165

Relevant changes:

- sysx/xattr: fix and improve
    - fix getxattrAll: change initial buffer size to 128 to prevent unneeded
      iterations and change the logic to get the real size in case we get ERANGE
      rather than doubling the buffer)
    - improve listxattrAll; refactor for readability, prevent calling `listxattr()`
      twice. Handle condition when attributes size is changed in between the two
      calls to listxattr().
- Remove Windows' Readlink fork
    - Drops support for Go 1.12 and under
- Fix sameFile() to recognize empty files as the same
    - fixes "Empty files can diff as "modified" even when they're not"

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

vendor.conf

@@ -124,7 +124,7 @@ google.golang.org/genproto                          3f1135a288c9a07e340ae8ba4cc6
 # containerd
 github.com/containerd/containerd                    c80284d4b5291a351bb471bcdabb5c1d95e7a583 # master / v1.4.0-dev
 github.com/containerd/fifo                          ff969a566b00877c63489baf6e8c35d60af6142c
-github.com/containerd/continuity                    26c1120b8d4107d2471b93ad78ef7ce1fc84c4c4
+github.com/containerd/continuity                    efbc4488d8fe1bdc16bde3b2d2990d9b3a899165
 github.com/containerd/cgroups                       44306b6a1d46985d916b48b4199f93a378af314f
 github.com/containerd/console                       8375c3424e4d7b114e8a90a4a40c8e1b40d1d4e6 # v1.0.0
 github.com/containerd/go-runc                       7016d3ce2328dd2cb1192b2076ebd565c4e8df0c

vendor/github.com/containerd/continuity/devices/devices_unix.go

@@ -32,6 +32,7 @@ func DeviceInfo(fi os.FileInfo) (uint64, uint64, error) {
 		return 0, 0, fmt.Errorf("cannot extract device from os.FileInfo")
 	}
 
+	//nolint:unconvert
 	dev := uint64(sys.Rdev)
 	return uint64(unix.Major(dev)), uint64(unix.Minor(dev)), nil
 }

vendor/github.com/containerd/continuity/driver/driver.go

@@ -138,6 +138,10 @@ func (d *driver) Lstat(p string) (os.FileInfo, error) {
 	return os.Lstat(p)
 }
 
+func (d *driver) Readlink(p string) (string, error) {
+	return os.Readlink(p)
+}
+
 func (d *driver) Mkdir(p string, mode os.FileMode) error {
 	return os.Mkdir(p, mode)
 }

vendor/github.com/containerd/continuity/driver/driver_unix.go

@@ -131,8 +131,3 @@ func (d *driver) LSetxattr(path string, attrMap map[string][]byte) error {
 func (d *driver) DeviceInfo(fi os.FileInfo) (maj uint64, min uint64, err error) {
 	return devices.DeviceInfo(fi)
 }
-
-// Readlink was forked on Windows to fix a Golang bug, use the "os" package here
-func (d *driver) Readlink(p string) (string, error) {
-	return os.Readlink(p)
-}

vendor/github.com/containerd/continuity/driver/driver_windows.go

@@ -1,3 +1,5 @@
+// +build go1.13
+
 /*
    Copyright The containerd Authors.
 
@@ -14,12 +16,14 @@
    limitations under the License.
 */
 
+// Go 1.13 is the minimally supported version for Windows.
+// Earlier golang releases have bug in os.Readlink
+// (see https://github.com/golang/go/issues/30463).
+
 package driver
 
 import (
 	"os"
-
-	"github.com/containerd/continuity/sysx"
 )
 
 func (d *driver) Mknod(path string, mode os.FileMode, major, minor int) error {
@@ -35,9 +39,3 @@ func (d *driver) Lchmod(path string, mode os.FileMode) (err error) {
 	// TODO: Use Window's equivalent
 	return os.Chmod(path, mode)
 }
-
-// Readlink is forked in order to support Volume paths which are used
-// in container layers.
-func (d *driver) Readlink(p string) (string, error) {
-	return sysx.Readlink(p)
-}

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/go.mod

@@ -1,6 +1,6 @@
 module github.com/containerd/continuity
 
-go 1.11
+go 1.13
 
 require (
 	bazil.org/fuse v0.0.0-20160811212531-371fbbdaa898

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

@@ -1,26 +0,0 @@
-// +build !windows
-
-/*
-   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"
-
-// Readlink returns the destination of the named symbolic link.
-func Readlink(path string, buf []byte) (n int, err error) {
-	return syscall.Readlink(path, buf)
-}

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/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
 		}
+		buf = make([]byte, n)
+		n, err = listFunc(path, buf)
+	}
+	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)
-			}
+	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
 	}
+
+	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