1 files changed, 23 insertions, 4 deletions
diff --git a/libgo/go/os/file.go b/libgo/go/os/file.go
index c13babe5f7f..7995de79bfc 100644
--- a/libgo/go/os/file.go
+++ b/libgo/go/os/file.go
@@ -228,6 +228,9 @@ func (f *File) WriteString(s string) (n int, err error) {
 // bits (before umask).
 // If there is an error, it will be of type *PathError.
 func Mkdir(name string, perm FileMode) error {
+	if runtime.GOOS == "windows" && isWindowsNulName(name) {
+		return &PathError{"mkdir", name, syscall.ENOTDIR}
+	}
 	e := syscall.Mkdir(fixLongPath(name), syscallMode(perm))
 
 	if e != nil {
@@ -247,7 +250,7 @@ func Mkdir(name string, perm FileMode) error {
 	return nil
 }
 
-// setStickyBit adds ModeSticky to the permision bits of path, non atomic.
+// setStickyBit adds ModeSticky to the permission bits of path, non atomic.
 func setStickyBit(name string) error {
 	fi, err := Stat(name)
 	if err != nil {
@@ -408,7 +411,7 @@ func UserCacheDir() (string, error) {
 // subdirectory within this one and use that.
 //
 // On Unix systems, it returns $XDG_CONFIG_HOME as specified by
-// https://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html if
+// https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html if
 // non-empty, else $HOME/.config.
 // On Darwin, it returns $HOME/Library/Application Support.
 // On Windows, it returns %AppData%.
@@ -472,8 +475,6 @@ func UserHomeDir() (string, error) {
 	}
 	// On some geese the home directory is not always defined.
 	switch runtime.GOOS {
-	case "nacl":
-		return "/", nil
 	case "android":
 		return "/sdcard", nil
 	case "darwin":
@@ -560,3 +561,21 @@ func (f *File) SyscallConn() (syscall.RawConn, error) {
 	}
 	return newRawConn(f)
 }
+
+// isWindowsNulName reports whether name is os.DevNull ('NUL') on Windows.
+// True is returned if name is 'NUL' whatever the case.
+func isWindowsNulName(name string) bool {
+	if len(name) != 3 {
+		return false
+	}
+	if name[0] != 'n' && name[0] != 'N' {
+		return false
+	}
+	if name[1] != 'u' && name[1] != 'U' {
+		return false
+	}
+	if name[2] != 'l' && name[2] != 'L' {
+		return false
+	}
+	return true
+}