vendor: update sources

```shell
dep ensure -update
```

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

vendor/golang.org/x/sys/unix/xattr_bsd.go

@@ -0,0 +1,240 @@
+// Copyright 2018 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.
+
+// +build freebsd netbsd
+
+package unix
+
+import (
+	"strings"
+	"unsafe"
+)
+
+// Derive extattr namespace and attribute name
+
+func xattrnamespace(fullattr string) (ns int, attr string, err error) {
+	s := strings.IndexByte(fullattr, '.')
+	if s == -1 {
+		return -1, "", ENOATTR
+	}
+
+	namespace := fullattr[0:s]
+	attr = fullattr[s+1:]
+
+	switch namespace {
+	case "user":
+		return EXTATTR_NAMESPACE_USER, attr, nil
+	case "system":
+		return EXTATTR_NAMESPACE_SYSTEM, attr, nil
+	default:
+		return -1, "", ENOATTR
+	}
+}
+
+func initxattrdest(dest []byte, idx int) (d unsafe.Pointer) {
+	if len(dest) > idx {
+		return unsafe.Pointer(&dest[idx])
+	} else {
+		return unsafe.Pointer(_zero)
+	}
+}
+
+// FreeBSD and NetBSD implement their own syscalls to handle extended attributes
+
+func Getxattr(file string, attr string, dest []byte) (sz int, err error) {
+	d := initxattrdest(dest, 0)
+	destsize := len(dest)
+
+	nsid, a, err := xattrnamespace(attr)
+	if err != nil {
+		return -1, err
+	}
+
+	return ExtattrGetFile(file, nsid, a, uintptr(d), destsize)
+}
+
+func Fgetxattr(fd int, attr string, dest []byte) (sz int, err error) {
+	d := initxattrdest(dest, 0)
+	destsize := len(dest)
+
+	nsid, a, err := xattrnamespace(attr)
+	if err != nil {
+		return -1, err
+	}
+
+	return ExtattrGetFd(fd, nsid, a, uintptr(d), destsize)
+}
+
+func Lgetxattr(link string, attr string, dest []byte) (sz int, err error) {
+	d := initxattrdest(dest, 0)
+	destsize := len(dest)
+
+	nsid, a, err := xattrnamespace(attr)
+	if err != nil {
+		return -1, err
+	}
+
+	return ExtattrGetLink(link, nsid, a, uintptr(d), destsize)
+}
+
+// flags are unused on FreeBSD
+
+func Fsetxattr(fd int, attr string, data []byte, flags int) (err error) {
+	var d unsafe.Pointer
+	if len(data) > 0 {
+		d = unsafe.Pointer(&data[0])
+	}
+	datasiz := len(data)
+
+	nsid, a, err := xattrnamespace(attr)
+	if err != nil {
+		return
+	}
+
+	_, err = ExtattrSetFd(fd, nsid, a, uintptr(d), datasiz)
+	return
+}
+
+func Setxattr(file string, attr string, data []byte, flags int) (err error) {
+	var d unsafe.Pointer
+	if len(data) > 0 {
+		d = unsafe.Pointer(&data[0])
+	}
+	datasiz := len(data)
+
+	nsid, a, err := xattrnamespace(attr)
+	if err != nil {
+		return
+	}
+
+	_, err = ExtattrSetFile(file, nsid, a, uintptr(d), datasiz)
+	return
+}
+
+func Lsetxattr(link string, attr string, data []byte, flags int) (err error) {
+	var d unsafe.Pointer
+	if len(data) > 0 {
+		d = unsafe.Pointer(&data[0])
+	}
+	datasiz := len(data)
+
+	nsid, a, err := xattrnamespace(attr)
+	if err != nil {
+		return
+	}
+
+	_, err = ExtattrSetLink(link, nsid, a, uintptr(d), datasiz)
+	return
+}
+
+func Removexattr(file string, attr string) (err error) {
+	nsid, a, err := xattrnamespace(attr)
+	if err != nil {
+		return
+	}
+
+	err = ExtattrDeleteFile(file, nsid, a)
+	return
+}
+
+func Fremovexattr(fd int, attr string) (err error) {
+	nsid, a, err := xattrnamespace(attr)
+	if err != nil {
+		return
+	}
+
+	err = ExtattrDeleteFd(fd, nsid, a)
+	return
+}
+
+func Lremovexattr(link string, attr string) (err error) {
+	nsid, a, err := xattrnamespace(attr)
+	if err != nil {
+		return
+	}
+
+	err = ExtattrDeleteLink(link, nsid, a)
+	return
+}
+
+func Listxattr(file string, dest []byte) (sz int, err error) {
+	d := initxattrdest(dest, 0)
+	destsiz := len(dest)
+
+	// FreeBSD won't allow you to list xattrs from multiple namespaces
+	s := 0
+	for _, nsid := range [...]int{EXTATTR_NAMESPACE_USER, EXTATTR_NAMESPACE_SYSTEM} {
+		stmp, e := ExtattrListFile(file, nsid, uintptr(d), destsiz)
+
+		/* Errors accessing system attrs are ignored so that
+		 * we can implement the Linux-like behavior of omitting errors that
+		 * we don't have read permissions on
+		 *
+		 * Linux will still error if we ask for user attributes on a file that
+		 * we don't have read permissions on, so don't ignore those errors
+		 */
+		if e != nil && e == EPERM && nsid != EXTATTR_NAMESPACE_USER {
+			continue
+		} else if e != nil {
+			return s, e
+		}
+
+		s += stmp
+		destsiz -= s
+		if destsiz < 0 {
+			destsiz = 0
+		}
+		d = initxattrdest(dest, s)
+	}
+
+	return s, nil
+}
+
+func Flistxattr(fd int, dest []byte) (sz int, err error) {
+	d := initxattrdest(dest, 0)
+	destsiz := len(dest)
+
+	s := 0
+	for _, nsid := range [...]int{EXTATTR_NAMESPACE_USER, EXTATTR_NAMESPACE_SYSTEM} {
+		stmp, e := ExtattrListFd(fd, nsid, uintptr(d), destsiz)
+		if e != nil && e == EPERM && nsid != EXTATTR_NAMESPACE_USER {
+			continue
+		} else if e != nil {
+			return s, e
+		}
+
+		s += stmp
+		destsiz -= s
+		if destsiz < 0 {
+			destsiz = 0
+		}
+		d = initxattrdest(dest, s)
+	}
+
+	return s, nil
+}
+
+func Llistxattr(link string, dest []byte) (sz int, err error) {
+	d := initxattrdest(dest, 0)
+	destsiz := len(dest)
+
+	s := 0
+	for _, nsid := range [...]int{EXTATTR_NAMESPACE_USER, EXTATTR_NAMESPACE_SYSTEM} {
+		stmp, e := ExtattrListLink(link, nsid, uintptr(d), destsiz)
+		if e != nil && e == EPERM && nsid != EXTATTR_NAMESPACE_USER {
+			continue
+		} else if e != nil {
+			return s, e
+		}
+
+		s += stmp
+		destsiz -= s
+		if destsiz < 0 {
+			destsiz = 0
+		}
+		d = initxattrdest(dest, s)
+	}
+
+	return s, nil
+}