syscall: fix windows SetFileAttributes

R=golang-dev, rsc, hector
CC=golang-dev, mattn
https://golang.org/cl/4180052

src/pkg/syscall/syscall_windows.go

@@ -154,7 +154,7 @@ func NewCallback(fn interface{}) uintptr
 //sys	SetEnvironmentVariable(name *uint16, value *uint16) (errno int) = kernel32.SetEnvironmentVariableW
 //sys	SetFileTime(handle int32, ctime *Filetime, atime *Filetime, wtime *Filetime) (errno int)
 //sys	GetFileAttributes(name *uint16) (attrs uint32, errno int) [failretval==INVALID_FILE_ATTRIBUTES] = kernel32.GetFileAttributesW
-//sys	SetFileAttributes(name *uint16, attrs uint32) (errno int) [failretval==INVALID_FILE_ATTRIBUTES] = kernel32.SetFileAttributesW
+//sys	SetFileAttributes(name *uint16, attrs uint32) (errno int) = kernel32.SetFileAttributesW
 //sys	GetCommandLine() (cmd *uint16) = kernel32.GetCommandLineW
 //sys	CommandLineToArgv(cmd *uint16, argc *int32) (argv *[8192]*[8192]uint16, errno int) [failretval==nil] = shell32.CommandLineToArgvW
 //sys	LocalFree(hmem uint32) (handle uint32, errno int) [failretval!=0]
@@ -471,6 +471,23 @@ func Fsync(fd int) (errno int) {
 	return FlushFileBuffers(int32(fd))
 }
 
+func Chmod(path string, mode uint32) (errno int) {
+	if mode == 0 {
+		return EINVAL
+	}
+	p := StringToUTF16Ptr(path)
+	attrs, e := GetFileAttributes(p)
+	if e != 0 {
+		return e
+	}
+	if mode&S_IWRITE != 0 {
+		attrs &^= FILE_ATTRIBUTE_READONLY
+	} else {
+		attrs |= FILE_ATTRIBUTE_READONLY
+	}
+	return SetFileAttributes(p, attrs)
+}
+
 // net api calls
 
 //sys	WSAStartup(verreq uint32, data *WSAData) (sockerrno int) = wsock32.WSAStartup
@@ -731,26 +748,6 @@ func Link(oldpath, newpath string) (errno int)            { return EWINDOWS }
 func Symlink(path, link string) (errno int)               { return EWINDOWS }
 func Readlink(path string, buf []byte) (n int, errno int) { return 0, EWINDOWS }
 
-func Chmod(path string, mode uint32) (errno int) {
-	attrs, errno := GetFileAttributes(StringToUTF16Ptr(path))
-	if errno != 0 {
-		return
-	}
-
-	if mode == 0 {
-		return EINVAL
-	}
-
-	if mode&S_IWRITE != 0 {
-		attrs &^= FILE_ATTRIBUTE_READONLY
-	} else if attrs&FILE_ATTRIBUTE_READONLY == 0 {
-		attrs |= FILE_ATTRIBUTE_READONLY
-	}
-
-	errno = SetFileAttributes(StringToUTF16Ptr(path), attrs)
-	return
-}
-
 func Fchmod(fd int, mode uint32) (errno int)           { return EWINDOWS }
 func Chown(path string, uid int, gid int) (errno int)  { return EWINDOWS }
 func Lchown(path string, uid int, gid int) (errno int) { return EWINDOWS }

src/pkg/syscall/zsyscall_windows_386.go

@@ -808,8 +808,8 @@ func GetFileAttributes(name *uint16) (attrs uint32, errno int) {
 }
 
 func SetFileAttributes(name *uint16, attrs uint32) (errno int) {
-	r0, _, e1 := Syscall(procSetFileAttributesW, 2, uintptr(unsafe.Pointer(name)), uintptr(attrs), 0)
-	if int(r0) == 0 {
+	r1, _, e1 := Syscall(procSetFileAttributesW, 2, uintptr(unsafe.Pointer(name)), uintptr(attrs), 0)
+	if int(r1) == 0 {
 		if e1 != 0 {
 			errno = int(e1)
 		} else {