1 files changed, 125 insertions, 0 deletions
diff --git a/vendor/github.com/containerd/continuity/sysx/xattr.go b/vendor/github.com/containerd/continuity/sysx/xattr.go
new file mode 100644
index 000000000..9e4326dcf
--- /dev/null
+++ b/vendor/github.com/containerd/continuity/sysx/xattr.go
@@ -0,0 +1,125 @@
+// +build linux darwin
+
+/*
+   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 (
+	"bytes"
+	"syscall"
+
+	"golang.org/x/sys/unix"
+)
+
+// Listxattr calls syscall listxattr and reads all content
+// and returns a string array
+func Listxattr(path string) ([]string, error) {
+	return listxattrAll(path, unix.Listxattr)
+}
+
+// Removexattr calls syscall removexattr
+func Removexattr(path string, attr string) (err error) {
+	return unix.Removexattr(path, attr)
+}
+
+// Setxattr calls syscall setxattr
+func Setxattr(path string, attr string, data []byte, flags int) (err error) {
+	return unix.Setxattr(path, attr, data, flags)
+}
+
+// Getxattr calls syscall getxattr
+func Getxattr(path, attr string) ([]byte, error) {
+	return getxattrAll(path, attr, unix.Getxattr)
+}
+
+// LListxattr lists xattrs, not following symlinks
+func LListxattr(path string) ([]string, error) {
+	return listxattrAll(path, unix.Llistxattr)
+}
+
+// LRemovexattr removes an xattr, not following symlinks
+func LRemovexattr(path string, attr string) (err error) {
+	return unix.Lremovexattr(path, attr)
+}
+
+// LSetxattr sets an xattr, not following symlinks
+func LSetxattr(path string, attr string, data []byte, flags int) (err error) {
+	return unix.Lsetxattr(path, attr, data, flags)
+}
+
+// LGetxattr gets an xattr, not following symlinks
+func LGetxattr(path, attr string) ([]byte, error) {
+	return getxattrAll(path, attr, unix.Lgetxattr)
+}
+
+const defaultXattrBufferSize = 5
+
+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.
+		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
+	}
+}
+
+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)
+		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
+	}
+}