Current definition of ENOATTR isn't helpful on Solaris (#75)

Author: andy-js

xattr_solaris.go

@@ -4,8 +4,8 @@
 package xattr
 
 import (
+	"errors"
 	"os"
-	"syscall"
 
 	"golang.org/x/sys/unix"
 )
@@ -17,10 +17,11 @@ const (
 	XATTR_CREATE  = 0x1
 	XATTR_REPLACE = 0x2
 
-	// ENOATTR is not exported by the syscall package on Linux, because it is
-	// an alias for ENODATA. We export it here so it is available on all
-	// our supported platforms.
-	ENOATTR = syscall.ENODATA
+	// ENOATTR is not defined on Solaris. When attempting to open an
+	// extended attribute that doesn't exist, we'll get ENOENT. For
+	// compatibility with other platforms, we make ENOATTR available as
+	// an alias of unix.ENOENT.
+	ENOATTR = unix.ENOENT
 )
 
 func getxattr(path string, name string, data []byte) (int, error) {
@@ -132,7 +133,13 @@ func llistxattr(path string, data []byte) (int, error) {
 func flistxattr(f *os.File, data []byte) (int, error) {
 	fd, err := unix.Openat(int(f.Fd()), ".", unix.O_RDONLY|unix.O_XATTR, 0)
 	if err != nil {
-		return 0, unix.ENOTSUP
+		// When attempting to list extended attributes on a filesystem
+		// that doesn't support them (like as UFS and tmpfs), we'll get
+		// EINVAL. Translate this error to the more conventional ENOTSUP.
+		if errors.Is(err, unix.EINVAL) {
+			return 0, unix.ENOTSUP
+		}
+		return 0, err
 	}
 	xf := os.NewFile(uintptr(fd), f.Name())
 	defer func() {