vnc: remove a memory leak in zlib

Makes sure we free all ressources used in zlib encoding (zlib stream
and buffer).
Signed-off-by: NCorentin Chary <corentincj@iksaif.net>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

vnc-encoding-zlib.c

@@ -140,3 +140,11 @@ void vnc_zlib_send_framebuffer_update(VncState *vs, int x, int y, int w, int h)
     vnc_write_u32(vs, bytes_written);
     vs->output.offset = new_offset;
 }
+
+void vnc_zlib_clear(VncState *vs)
+{
+    if (vs->zlib_stream.opaque) {
+        deflateEnd(&vs->zlib_stream);
+    }
+    buffer_free(&vs->zlib);
+}

vnc.c

@@ -974,6 +974,8 @@ static void vnc_disconnect_finish(VncState *vs)
 
     qobject_decref(vs->info);
 
+    vnc_zlib_clear(vs);
+
 #ifdef CONFIG_VNC_TLS
     vnc_tls_client_cleanup(vs);
 #endif /* CONFIG_VNC_TLS */

vnc.h

@@ -405,5 +405,6 @@ void vnc_hextile_send_framebuffer_update(VncState *vs, int x,
 void vnc_hextile_set_pixel_conversion(VncState *vs, int generic);
 
 void vnc_zlib_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
+void vnc_zlib_clear(VncState *vs);
 
 #endif /* __QEMU_VNC_H */