Fix memory leak

Pass Go a pointer to the CGOBitmap, otherwise Rust assumes ownership
is passing through the FFI and will not free the memory when we're
finished with it.

lib/srv/desktop/rdp/rdpclient/client.go

@@ -382,11 +382,11 @@ func (c *Client) start() {
 }
 
 //export handle_bitmap
-func handle_bitmap(handle C.uintptr_t, cb C.CGOBitmap) C.CGOError {
+func handle_bitmap(handle C.uintptr_t, cb *C.CGOBitmap) C.CGOError {
 	return cgo.Handle(handle).Value().(*Client).handleBitmap(cb)
 }
 
-func (c *Client) handleBitmap(cb C.CGOBitmap) C.CGOError {
+func (c *Client) handleBitmap(cb *C.CGOBitmap) C.CGOError {
 	// Notify the input forwarding goroutine that we're ready for input.
 	// Input can only be sent after connection was established, which we infer
 	// from the fact that a bitmap was sent.

lib/srv/desktop/rdp/rdpclient/librdprs.h

@@ -178,6 +178,6 @@ void free_rust_string(char *s);
 
 extern void free_go_string(char *s);
 
-extern CGOError handle_bitmap(uintptr_t client_ref, struct CGOBitmap b);
+extern CGOError handle_bitmap(uintptr_t client_ref, struct CGOBitmap *b);
 
 extern CGOError handle_remote_copy(uintptr_t client_ref, uint8_t *data, uint32_t len);

lib/srv/desktop/rdp/rdpclient/src/lib.rs

@@ -458,7 +458,7 @@ fn read_rdp_output_inner(client: &Client) -> Option<String> {
             .unwrap()
             .read(|rdp_event| match rdp_event {
                 RdpEvent::Bitmap(bitmap) => {
-                    let cbitmap = match CGOBitmap::try_from(bitmap) {
+                    let mut cbitmap = match CGOBitmap::try_from(bitmap) {
                         Ok(cb) => cb,
                         Err(e) => {
                             error!(
@@ -469,7 +469,7 @@ fn read_rdp_output_inner(client: &Client) -> Option<String> {
                         }
                     };
                     unsafe {
-                        err = handle_bitmap(client_ref, cbitmap) as CGOError;
+                        err = handle_bitmap(client_ref, &mut cbitmap) as CGOError;
                     };
                 }
                 // These should never really be sent by the server to us.
@@ -696,8 +696,7 @@ unsafe fn from_cgo_error(e: CGOError) -> String {
 // comments.
 extern "C" {
     fn free_go_string(s: *mut c_char);
-    fn handle_bitmap(client_ref: usize, b: CGOBitmap) -> CGOError;
-
+    fn handle_bitmap(client_ref: usize, b: *mut CGOBitmap) -> CGOError;
     fn handle_remote_copy(client_ref: usize, data: *mut u8, len: u32) -> CGOError;
 }