fs: add file ext attr support for Darwin and FreeBSD and fix loopback fs

test

Change-Id: Idcb3ee99c1afdde410e41e3a67c29c3143f602c3

fs/constants_darwin.go

-// Copyright 2019 the Go-FUSE Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package fs
-
-import "syscall"
-
-// ENOATTR indicates that an extended attribute was not present.
-var ENOATTR = syscall.ENOATTR

fs/constants_linux.go

@@ -4,7 +4,7 @@
 
 package fs
 
-import "syscall"
+import "golang.org/x/sys/unix"
 
 // ENOATTR indicates that an extended attribute was not present.
-var ENOATTR = syscall.ENODATA
+const ENOATTR = unix.ENODATA

fs/constants_unix.go

+//go:build !linux
+
+package fs
+
+import "golang.org/x/sys/unix"
+
+const ENOATTR = unix.ENOATTR

fs/loopback.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/hanwen/go-fuse/v2/fuse"
 	"github.com/hanwen/go-fuse/v2/internal/renameat"
+	"golang.org/x/sys/unix"
 )
 
 // LoopbackRoot holds the parameters for creating a new loopback
@@ -441,6 +442,46 @@ func (n *LoopbackNode) Setattr(ctx context.Context, f FileHandle, in *fuse.SetAt
 	return OK
 }
 
+var _ = (NodeGetxattrer)((*LoopbackNode)(nil))
+
+func (n *LoopbackNode) Getxattr(ctx context.Context, attr string, dest []byte) (uint32, syscall.Errno) {
+	sz, err := unix.Lgetxattr(n.path(), attr, dest)
+	return uint32(sz), ToErrno(err)
+}
+
+var _ = (NodeSetxattrer)((*LoopbackNode)(nil))
+
+func (n *LoopbackNode) Setxattr(ctx context.Context, attr string, data []byte, flags uint32) syscall.Errno {
+	err := unix.Lsetxattr(n.path(), attr, data, int(flags))
+	return ToErrno(err)
+}
+
+var _ = (NodeRemovexattrer)((*LoopbackNode)(nil))
+
+func (n *LoopbackNode) Removexattr(ctx context.Context, attr string) syscall.Errno {
+	err := unix.Lremovexattr(n.path(), attr)
+	return ToErrno(err)
+}
+
+var _ = (NodeCopyFileRanger)((*LoopbackNode)(nil))
+
+func (n *LoopbackNode) CopyFileRange(ctx context.Context, fhIn FileHandle,
+	offIn uint64, out *Inode, fhOut FileHandle, offOut uint64,
+	len uint64, flags uint64) (uint32, syscall.Errno) {
+	lfIn, ok := fhIn.(*loopbackFile)
+	if !ok {
+		return 0, unix.ENOTSUP
+	}
+	lfOut, ok := fhOut.(*loopbackFile)
+	if !ok {
+		return 0, unix.ENOTSUP
+	}
+	signedOffIn := int64(offIn)
+	signedOffOut := int64(offOut)
+	doCopyFileRange(lfIn.fd, signedOffIn, lfOut.fd, signedOffOut, int(len), int(flags))
+	return 0, syscall.ENOSYS
+}
+
 // NewLoopbackRoot returns a root node for a loopback file system whose
 // root is at the given root. This node implements all NodeXxxxer
 // operations available.

fs/loopback_darwin.go

@@ -8,35 +8,10 @@
 package fs
 
 import (
-	"context"
 	"syscall"
 	"time"
 )
 
-var _ = (NodeGetxattrer)((*LoopbackNode)(nil))
-
-func (n *LoopbackNode) Getxattr(ctx context.Context, attr string, dest []byte) (uint32, syscall.Errno) {
-	return 0, syscall.ENOSYS
-}
-
-var _ = (NodeSetxattrer)((*LoopbackNode)(nil))
-
-func (n *LoopbackNode) Setxattr(ctx context.Context, attr string, data []byte, flags uint32) syscall.Errno {
-	return syscall.ENOSYS
-}
-
-var _ = (NodeRemovexattrer)((*LoopbackNode)(nil))
-
-func (n *LoopbackNode) Removexattr(ctx context.Context, attr string) syscall.Errno {
-	return syscall.ENOSYS
-}
-
-var _ = (NodeListxattrer)((*LoopbackNode)(nil))
-
-func (n *LoopbackNode) Listxattr(ctx context.Context, dest []byte) (uint32, syscall.Errno) {
-	return 0, syscall.ENOSYS
-}
-
 // timeToTimeval - Convert time.Time to syscall.Timeval
 //
 // Note: This does not use syscall.NsecToTimespec because
@@ -49,11 +24,8 @@ func timeToTimeval(t *time.Time) syscall.Timeval {
 	return tv
 }
 
-var _ = (NodeCopyFileRanger)((*LoopbackNode)(nil))
-
-func (n *LoopbackNode) CopyFileRange(ctx context.Context, fhIn FileHandle,
-	offIn uint64, out *Inode, fhOut FileHandle, offOut uint64,
-	len uint64, flags uint64) (uint32, syscall.Errno) {
+func doCopyFileRange(fdIn int, offIn int64, fdOut int, offOut int64,
+	len int, flags int) (uint32, syscall.Errno) {
 	return 0, syscall.ENOSYS
 }
 

fs/loopback_freebsd.go

@@ -3,40 +3,86 @@ package fs
 import (
 	"context"
 	"syscall"
+
+	"golang.org/x/sys/unix"
 )
 
-var _ = (NodeGetxattrer)((*LoopbackNode)(nil))
+// FreeBSD has added copy_file_range(2) since FreeBSD 12. However,
+// golang.org/x/sys/unix hasn't add corresponding syscall constant or
+// wrap function. Here we define the syscall constant until sys/unix
+// provides.
+const sys_COPY_FILE_RANGE = 569
 
-func (n *LoopbackNode) Getxattr(ctx context.Context, attr string, dest []byte) (uint32, syscall.Errno) {
-	return 0, syscall.ENOSYS
+// TODO: replace the manual syscall when sys/unix provides CopyFileRange
+// for FreeBSD
+func doCopyFileRange(fdIn int, offIn int64, fdOut int, offOut int64,
+	len int, flags int) (uint32, syscall.Errno) {
+	count, _, errno := unix.Syscall6(sys_COPY_FILE_RANGE,
+		uintptr(fdIn), uintptr(offIn), uintptr(fdOut), uintptr(offOut),
+		uintptr(len), uintptr(flags),
+	)
+	return uint32(count), errno
 }
 
-var _ = (NodeSetxattrer)((*LoopbackNode)(nil))
-
-func (n *LoopbackNode) Setxattr(ctx context.Context, attr string, data []byte, flags uint32) syscall.Errno {
-	return syscall.ENOSYS
+func intDev(dev uint32) uint64 {
+	return uint64(dev)
 }
 
-var _ = (NodeRemovexattrer)((*LoopbackNode)(nil))
+// BSDs syscall use different convention of data buf retrieved
+// through syscall `unix.Listxattr`.
+// Ref: extattr_list_file(2)
+func retrieveAttrName(buf []byte) [][]byte {
+	var attrList [][]byte
+	for p := 0; p < len(buf); {
+		attrNameLen := int(buf[p])
+		p++
+		attrName := buf[p : p+attrNameLen]
+		attrList = append(attrList, attrName)
+		p += attrNameLen
+	}
+	return attrList
+}
 
-func (n *LoopbackNode) Removexattr(ctx context.Context, attr string) syscall.Errno {
-	return syscall.ENOSYS
+// Since FUSE on FreeBSD expect Linux flavor data format of
+// listxattr, we should reconstruct it with data returned by
+// FreeBSD's syscall. And here we have added a "user." prefix
+// to put them under "user" namespace, which is readable and
+// writable for normal user, for a userspace implemented FS.
+func rebuildAttrBuf(attrList [][]byte) []byte {
+	ret := make([]byte, 0)
+	for _, attrName := range attrList {
+		nsAttrName := append([]byte("user."), attrName...)
+		ret = append(ret, nsAttrName...)
+		ret = append(ret, 0x0)
+	}
+	return ret
 }
 
 var _ = (NodeListxattrer)((*LoopbackNode)(nil))
 
 func (n *LoopbackNode) Listxattr(ctx context.Context, dest []byte) (uint32, syscall.Errno) {
-	return 0, syscall.ENOSYS
-}
-
-var _ = (NodeCopyFileRanger)((*LoopbackNode)(nil))
-
-func (n *LoopbackNode) CopyFileRange(ctx context.Context, fhIn FileHandle,
-	offIn uint64, out *Inode, fhOut FileHandle, offOut uint64,
-	len uint64, flags uint64) (uint32, syscall.Errno) {
-	return 0, syscall.ENOSYS
-}
-
-func intDev(dev uint32) uint64 {
-	return uint64(dev)
+	// In order to simulate same data format as Linux does,
+	// and the size of returned buf is required to match, we must
+	// call unix.Llistxattr twice.
+	sz, err := unix.Llistxattr(n.path(), nil)
+	if err != nil {
+		return uint32(sz), ToErrno(err)
+	}
+	rawBuf := make([]byte, sz)
+	sz, err = unix.Llistxattr(n.path(), rawBuf)
+	if err != nil {
+		return uint32(sz), ToErrno(err)
+	}
+	attrList := retrieveAttrName(rawBuf)
+	rebuiltBuf := rebuildAttrBuf(attrList)
+	sz = len(rebuiltBuf)
+	if len(dest) != 0 {
+		// When len(dest) is 0, which means that caller wants to get
+		// the size. If len(dest) is less than len(rebuiltBuf), but greater
+		// than 0 dest will be also filled with data from rebuiltBuf,
+		// but truncated to len(dest). copy() function will do the same.
+		// And this behaviour is same as FreeBSD's syscall extattr_list_file(2).
+		sz = copy(dest, rebuiltBuf)
+	}
+	return uint32(sz), ToErrno(err)
 }

fs/loopback_linux.go

@@ -8,57 +8,14 @@
 package fs
 
 import (
-	"context"
 	"syscall"
 
 	"golang.org/x/sys/unix"
 )
 
-var _ = (NodeGetxattrer)((*LoopbackNode)(nil))
-
-func (n *LoopbackNode) Getxattr(ctx context.Context, attr string, dest []byte) (uint32, syscall.Errno) {
-	sz, err := unix.Lgetxattr(n.path(), attr, dest)
-	return uint32(sz), ToErrno(err)
-}
-
-var _ = (NodeSetxattrer)((*LoopbackNode)(nil))
-
-func (n *LoopbackNode) Setxattr(ctx context.Context, attr string, data []byte, flags uint32) syscall.Errno {
-	err := unix.Lsetxattr(n.path(), attr, data, int(flags))
-	return ToErrno(err)
-}
-
-var _ = (NodeRemovexattrer)((*LoopbackNode)(nil))
-
-func (n *LoopbackNode) Removexattr(ctx context.Context, attr string) syscall.Errno {
-	err := unix.Lremovexattr(n.path(), attr)
-	return ToErrno(err)
-}
-
-var _ = (NodeListxattrer)((*LoopbackNode)(nil))
-
-func (n *LoopbackNode) Listxattr(ctx context.Context, dest []byte) (uint32, syscall.Errno) {
-	sz, err := unix.Llistxattr(n.path(), dest)
-	return uint32(sz), ToErrno(err)
-}
-
-var _ = (NodeCopyFileRanger)((*LoopbackNode)(nil))
-
-func (n *LoopbackNode) CopyFileRange(ctx context.Context, fhIn FileHandle,
-	offIn uint64, out *Inode, fhOut FileHandle, offOut uint64,
-	len uint64, flags uint64) (uint32, syscall.Errno) {
-	lfIn, ok := fhIn.(*loopbackFile)
-	if !ok {
-		return 0, syscall.ENOTSUP
-	}
-	lfOut, ok := fhOut.(*loopbackFile)
-	if !ok {
-		return 0, syscall.ENOTSUP
-	}
-
-	signedOffIn := int64(offIn)
-	signedOffOut := int64(offOut)
-	count, err := unix.CopyFileRange(lfIn.fd, &signedOffIn, lfOut.fd, &signedOffOut, int(len), int(flags))
+func doCopyFileRange(fdIn int, offIn int64, fdOut int, offOut int64,
+	len int, flags int) (uint32, syscall.Errno) {
+	count, err := unix.CopyFileRange(fdIn, &offIn, fdOut, &offOut, len, flags)
 	return uint32(count), ToErrno(err)
 }
 

fs/loopback_linux_test.go

@@ -45,63 +45,6 @@ func TestRenameNoOverwrite(t *testing.T) {
 	}
 }
 
-func TestXAttr(t *testing.T) {
-	tc := newTestCase(t, &testOptions{attrCache: true, entryCache: true})
-
-	tc.writeOrig("file", "", 0644)
-
-	buf := make([]byte, 1024)
-	attr := "user.xattrtest"
-	if _, err := syscall.Getxattr(tc.mntDir+"/file", attr, buf); err == syscall.ENOTSUP {
-		t.Skip("$TMP does not support xattrs. Rerun this test with a $TMPDIR override")
-	}
-
-	if _, err := syscall.Getxattr(tc.mntDir+"/file", attr, buf); err != syscall.ENODATA {
-		t.Fatalf("got %v want ENOATTR", err)
-	}
-	value := []byte("value")
-	if err := syscall.Setxattr(tc.mntDir+"/file", attr, value, 0); err != nil {
-		t.Fatalf("Setxattr: %v", err)
-	}
-
-	sz, err := syscall.Listxattr(tc.mntDir+"/file", nil)
-	if err != nil {
-		t.Fatalf("Listxattr: %v", err)
-	}
-	buf = make([]byte, sz)
-	if _, err := syscall.Listxattr(tc.mntDir+"/file", buf); err != nil {
-		t.Fatalf("Listxattr: %v", err)
-	} else {
-		attributes := bytes.Split(buf[:sz], []byte{0})
-		found := false
-		for _, a := range attributes {
-			if string(a) == attr {
-				found = true
-				break
-			}
-		}
-
-		if !found {
-			t.Fatalf("Listxattr: %q (not found: %q", buf[:sz], attr)
-		}
-	}
-
-	sz, err = syscall.Getxattr(tc.mntDir+"/file", attr, buf)
-	if err != nil {
-		t.Fatalf("Getxattr: %v", err)
-	}
-	if bytes.Compare(buf[:sz], value) != 0 {
-		t.Fatalf("Getxattr got %q want %q", buf[:sz], value)
-	}
-	if err := syscall.Removexattr(tc.mntDir+"/file", attr); err != nil {
-		t.Fatalf("Removexattr: %v", err)
-	}
-
-	if _, err := syscall.Getxattr(tc.mntDir+"/file", attr, buf); err != syscall.ENODATA {
-		t.Fatalf("got %v want ENOATTR", err)
-	}
-}
-
 // TestXAttrSymlink verifies that we did not forget to use Lgetxattr instead
 // of Getxattr. This test is Linux-specific because it depends on the behavoir
 // of the `security` namespace.

fs/loopback_test.go

 package fs
 
 import (
+	"bytes"
+	"fmt"
 	"os"
 	"reflect"
 	"syscall"
@@ -40,7 +42,11 @@ func TestRenameExchange(t *testing.T) {
 	}
 
 	if err := renameat.Renameat(f1, "file", f2, "file", renameat.RENAME_EXCHANGE); err != nil {
-		t.Errorf("rename EXCHANGE: %v", err)
+		if err == unix.ENOSYS {
+			t.Skip("rename EXCHANGE not support on current system")
+		} else {
+			t.Errorf("rename EXCHANGE: %v", err)
+		}
 	}
 
 	var after1, after2 unix.Stat_t
@@ -82,3 +88,62 @@ func TestRenameExchange(t *testing.T) {
 		t.Errorf("got inode %d for %q want %d", ino2.StableAttr().Ino, "dir/file", after2.Ino)
 	}
 }
+
+func TestXAttr(t *testing.T) {
+	tc := newTestCase(t, &testOptions{attrCache: true, entryCache: true})
+
+	tc.writeOrig("file", "", 0644)
+
+	buf := make([]byte, 1024)
+	attrNameSpace := "user"
+	attrName := "xattrtest"
+	attr := fmt.Sprintf("%s.%s", attrNameSpace, attrName)
+	if _, err := unix.Getxattr(tc.mntDir+"/file", attr, buf); err == unix.ENOTSUP {
+		t.Skip("$TMP does not support xattrs. Rerun this test with a $TMPDIR override")
+	}
+
+	if _, err := unix.Getxattr(tc.mntDir+"/file", attr, buf); err != ENOATTR {
+		t.Fatalf("got %v want ENOATTR", err)
+	}
+	value := []byte("value")
+	if err := unix.Setxattr(tc.mntDir+"/file", attr, value, 0); err != nil {
+		t.Fatalf("Setxattr: %v", err)
+	}
+
+	sz, err := unix.Listxattr(tc.mntDir+"/file", nil)
+	if err != nil {
+		t.Fatalf("Listxattr: %v", err)
+	}
+	buf = make([]byte, sz)
+	if _, err := unix.Listxattr(tc.mntDir+"/file", buf); err != nil {
+		t.Fatalf("Listxattr: %v", err)
+	} else {
+		attributes := retrieveAttrName(buf[:sz])
+		found := false
+		for _, a := range attributes {
+			if string(a) == attr || attrNameSpace+string(a) == attr {
+				found = true
+				break
+			}
+		}
+
+		if !found {
+			t.Fatalf("Listxattr: %q (not found: %q", attributes, attr)
+		}
+	}
+
+	sz, err = unix.Getxattr(tc.mntDir+"/file", attr, buf)
+	if err != nil {
+		t.Fatalf("Getxattr: %v", err)
+	}
+	if bytes.Compare(buf[:sz], value) != 0 {
+		t.Fatalf("Getxattr got %q want %q", buf[:sz], value)
+	}
+	if err := unix.Removexattr(tc.mntDir+"/file", attr); err != nil {
+		t.Fatalf("Removexattr: %v", err)
+	}
+
+	if _, err := unix.Getxattr(tc.mntDir+"/file", attr, buf); err != ENOATTR {
+		t.Fatalf("got %v want ENOATTR", err)
+	}
+}

fs/loopback_unix.go

+//go:build !freebsd
+
+package fs
+
+import (
+	"bytes"
+	"context"
+	"syscall"
+
+	"golang.org/x/sys/unix"
+)
+
+func retrieveAttrName(buf []byte) [][]byte {
+	attributes := bytes.Split(buf, []byte{0})
+	return attributes
+}
+
+var _ = (NodeListxattrer)((*LoopbackNode)(nil))
+
+func (n *LoopbackNode) Listxattr(ctx context.Context, dest []byte) (uint32, syscall.Errno) {
+	sz, err := unix.Llistxattr(n.path(), dest)
+	return uint32(sz), ToErrno(err)
+}