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

241 lines
5.0 KiB
Go

// 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
}