notify in case of permissions problem on the hidraw device

app/solaar.py

@@ -83,7 +83,11 @@ if __name__ == '__main__':
 		global listener, notify_missing
 
 		if listener is None:
+			try:
 				listener = ReceiverListener.open(status_changed)
+			except OSError:
+				ui.show_permissions_warning(window)
+
 			if listener is None:
 				pairing.state = None
 				if notify_missing:

app/ui/__init__.py

@@ -26,6 +26,16 @@ def icon_file(name):
 	return None
 
 
+def show_permissions_warning(window):
+	text = ('Found a possible Unifying Receiver device,\n'
+			'but did not have permission to open it.')
+
+	m = Gtk.MessageDialog(window, Gtk.DialogFlags.MODAL, Gtk.MessageType.ERROR, Gtk.ButtonsType.CLOSE, text)
+	m.set_title('Permissions error')
+	m.run()
+	m.destroy()
+
+
 def find_children(container, *child_names):
 	assert container is not None
 

lib/hidapi/udev.py

@@ -120,10 +120,7 @@ def open_path(device_path):
 
 	:returns: an opaque device handle, or ``None``.
 	"""
-	try:
 	return _os.open(device_path, _os.O_RDWR | _os.O_SYNC)
-	except:
-		pass
 
 
 def close(device_handle):

lib/logitech/unifying_receiver/api.py

@@ -4,6 +4,7 @@
 
 from struct import pack as _pack
 from struct import unpack as _unpack
+import errno as _errno
 
 
 from . import base as _base
@@ -164,10 +165,22 @@ class Receiver(object):
 
 		:returns: An open file handle for the found receiver, or ``None``.
 		"""
+		exception = None
+
 		for rawdevice in _base.list_receiver_devices():
+			exception = None
+			try:
 				handle = _base.try_open(rawdevice.path)
 				if handle:
 					return Receiver(handle, rawdevice.path)
+			except OSError as e:
+				_log.exception("open %s", rawdevice.path)
+				if e.errno == _errno.EACCES:
+					exception = e
+
+		if exception:
+			# only keep the last exception
+			raise exception
 
 #
 #