unix: add namespaced versions of Listxattr/Flistxattr/Llistxattr on *BSD
Current extended attributes API mixes together attributes from different
namespaces without a way to separate them. Add versions of *listxattr
functions that return attributes only from the specified namespace.
For golang/go#54357
Change-Id: I605d677dd2f2a17541bc02f3146a7509c69269c9
Reviewed-on: https://go-review.googlesource.com/c/sys/+/430215
Reviewed-by: Yuval Pavel Zholkover <paulzhol@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Dmitri Goutnik <dgoutnik@gmail.com>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Jenny Rakoczy <jenny@golang.org>
Reviewed-by: Jenny Rakoczy <jenny@golang.org>
diff --git a/unix/xattr_bsd.go b/unix/xattr_bsd.go
index 25df1e3..663b377 100644
--- a/unix/xattr_bsd.go
+++ b/unix/xattr_bsd.go
@@ -160,13 +160,12 @@
}
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
+ s, pos := 0, 0
for _, nsid := range [...]int{EXTATTR_NAMESPACE_USER, EXTATTR_NAMESPACE_SYSTEM} {
- stmp, e := ExtattrListFile(file, nsid, uintptr(d), destsiz)
+ stmp, e := ListxattrNS(file, nsid, dest[pos:])
/* Errors accessing system attrs are ignored so that
* we can implement the Linux-like behavior of omitting errors that
@@ -175,66 +174,102 @@
* 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 {
+ if e != nil {
+ if e == EPERM && nsid != EXTATTR_NAMESPACE_USER {
+ continue
+ }
return s, e
}
s += stmp
- destsiz -= s
- if destsiz < 0 {
- destsiz = 0
+ pos = s
+ if pos > destsiz {
+ pos = destsiz
}
- d = initxattrdest(dest, s)
+ }
+
+ return s, nil
+}
+
+func ListxattrNS(file string, nsid int, dest []byte) (sz int, err error) {
+ d := initxattrdest(dest, 0)
+ destsiz := len(dest)
+
+ s, e := ExtattrListFile(file, nsid, uintptr(d), destsiz)
+ if e != nil {
+ return 0, err
}
return s, nil
}
func Flistxattr(fd int, dest []byte) (sz int, err error) {
- d := initxattrdest(dest, 0)
destsiz := len(dest)
- s := 0
+ s, pos := 0, 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 {
+ stmp, e := FlistxattrNS(fd, nsid, dest[pos:])
+
+ if e != nil {
+ if e == EPERM && nsid != EXTATTR_NAMESPACE_USER {
+ continue
+ }
return s, e
}
s += stmp
- destsiz -= s
- if destsiz < 0 {
- destsiz = 0
+ pos = s
+ if pos > destsiz {
+ pos = destsiz
}
- d = initxattrdest(dest, s)
+ }
+
+ return s, nil
+}
+
+func FlistxattrNS(fd int, nsid int, dest []byte) (sz int, err error) {
+ d := initxattrdest(dest, 0)
+ destsiz := len(dest)
+
+ s, e := ExtattrListFd(fd, nsid, uintptr(d), destsiz)
+ if e != nil {
+ return 0, err
}
return s, nil
}
func Llistxattr(link string, dest []byte) (sz int, err error) {
- d := initxattrdest(dest, 0)
destsiz := len(dest)
- s := 0
+ s, pos := 0, 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 {
+ stmp, e := LlistxattrNS(link, nsid, dest[pos:])
+
+ if e != nil {
+ if e == EPERM && nsid != EXTATTR_NAMESPACE_USER {
+ continue
+ }
return s, e
}
s += stmp
- destsiz -= s
- if destsiz < 0 {
- destsiz = 0
+ pos = s
+ if pos > destsiz {
+ pos = destsiz
}
- d = initxattrdest(dest, s)
+ }
+
+ return s, nil
+}
+
+func LlistxattrNS(link string, nsid int, dest []byte) (sz int, err error) {
+ d := initxattrdest(dest, 0)
+ destsiz := len(dest)
+
+ s, e := ExtattrListLink(link, nsid, uintptr(d), destsiz)
+ if e != nil {
+ return 0, err
}
return s, nil
