device: let devices call stage1 again after being ready to proceed

I am about to change the when stage1 gets postponed, then the way to
proceed it is to schedule stage1 again (instead of scheduling stage2).

The reason is that stage1 handling should be reentrant and we should
keep entering it until there is no more reason to postpone it. If
a subclass postpones stage1 and then later progresses it by directly
scheduling stage2, then only the subclass is in control over postponing
stage 2.

Instead, anybody should be able to delay stage2 independently. That can
only work if everybody signals readyness to proceed by scheduling stage1
again.

1 files changed, 37 insertions, 15 deletions

diff --git a/src/devices/wwan/nm-device-modem.c b/src/devices/wwan/nm-device-modem.c
index be0993916d..7ba664394a 100644
--- a/src/devices/wwan/nm-device-modem.c
+++ b/src/devices/wwan/nm-device-modem.c
@@ -48,10 +48,11 @@ typedef struct {
 	NMModem *modem;
 	NMDeviceModemCapabilities caps;
 	NMDeviceModemCapabilities current_caps;
-	gboolean rf_enabled;
 	char *device_id;
 	char *operator_code;
 	char *apn;
+	bool rf_enabled:1;
+	NMDeviceStageState stage1_state:3;
 } NMDeviceModemPrivate;
 
 struct _NMDeviceModem {
@@ -119,16 +120,17 @@ modem_prepare_result (NMModem *modem,
                       gpointer user_data)
 {
 	NMDeviceModem *self = NM_DEVICE_MODEM (user_data);
+	NMDeviceModemPrivate *priv = NM_DEVICE_MODEM_GET_PRIVATE (self);
 	NMDevice *device = NM_DEVICE (self);
-	NMDeviceState state;
 	NMDeviceStateReason reason = i_reason;
 
-	state = nm_device_get_state (device);
-	g_return_if_fail (state == NM_DEVICE_STATE_PREPARE);
+	if (   nm_device_get_state (device) != NM_DEVICE_STATE_PREPARE
+	    || priv->stage1_state != NM_DEVICE_STAGE_STATE_PENDING) {
+		nm_assert_not_reached ();
+		success = FALSE;
+	}
 
-	if (success)
-		nm_device_activate_schedule_stage2_device_config (device);
-	else {
+	if (!success) {
 		/* There are several reasons to block autoconnection at device level:
 		 *
 		 *  - Wrong SIM-PIN: The device won't autoconnect because it doesn't make sense
@@ -164,7 +166,11 @@ modem_prepare_result (NMModem *modem,
 			break;
 		}
 		nm_device_state_changed (device, NM_DEVICE_STATE_FAILED, reason);
+		return;
 	}
+
+	priv->stage1_state = NM_DEVICE_STAGE_STATE_COMPLETED;
+	nm_device_activate_schedule_stage1_device_prepare (device);
 }
 
 static void
@@ -187,16 +193,19 @@ static void
 modem_auth_result (NMModem *modem, GError *error, gpointer user_data)
 {
 	NMDevice *device = NM_DEVICE (user_data);
+	NMDeviceModemPrivate *priv = NM_DEVICE_MODEM_GET_PRIVATE (device);
+
+	g_return_if_fail (nm_device_get_state (device) == NM_DEVICE_STATE_NEED_AUTH);
 
 	if (error) {
 		nm_device_state_changed (device,
 		                         NM_DEVICE_STATE_FAILED,
 		                         NM_DEVICE_STATE_REASON_NO_SECRETS);
-	} else {
-		/* Otherwise, on success for modem secrets we need to schedule stage1 again */
-		g_return_if_fail (nm_device_get_state (device) == NM_DEVICE_STATE_NEED_AUTH);
-		nm_device_activate_schedule_stage1_device_prepare (device);
+		return;
 	}
+
+	priv->stage1_state = NM_DEVICE_STAGE_STATE_INIT;
+	nm_device_activate_schedule_stage1_device_prepare (device);
 }
 
 static void
@@ -542,7 +551,10 @@ complete_connection (NMDevice *device,
 static void
 deactivate (NMDevice *device)
 {
-	nm_modem_deactivate (NM_DEVICE_MODEM_GET_PRIVATE (device)->modem, device);
+	NMDeviceModemPrivate *priv = NM_DEVICE_MODEM_GET_PRIVATE (device);
+
+	nm_modem_deactivate (priv->modem, device);
+	priv->stage1_state = NM_DEVICE_STAGE_STATE_INIT;
 }
 
 /*****************************************************************************/
@@ -583,14 +595,24 @@ deactivate_async (NMDevice *self,
 static NMActStageReturn
 act_stage1_prepare (NMDevice *device, NMDeviceStateReason *out_failure_reason)
 {
+	NMDeviceModemPrivate *priv = NM_DEVICE_MODEM_GET_PRIVATE (device);
 	NMActRequest *req;
 
 	req = nm_device_get_act_request (device);
 	g_return_val_if_fail (req, NM_ACT_STAGE_RETURN_FAILURE);
 
-	return nm_modem_act_stage1_prepare (NM_DEVICE_MODEM_GET_PRIVATE (device)->modem,
-	                                    req,
-	                                    out_failure_reason);
+	if (priv->stage1_state == NM_DEVICE_STAGE_STATE_INIT) {
+		priv->stage1_state = NM_DEVICE_STAGE_STATE_PENDING;
+		return nm_modem_act_stage1_prepare (NM_DEVICE_MODEM_GET_PRIVATE (device)->modem,
+		                                    req,
+		                                    out_failure_reason);
+	}
+
+	if (priv->stage1_state == NM_DEVICE_STAGE_STATE_PENDING)
+		return NM_ACT_STAGE_RETURN_POSTPONE;
+
+	nm_assert (priv->stage1_state == NM_DEVICE_STAGE_STATE_COMPLETED);
+	return NM_ACT_STAGE_RETURN_SUCCESS;
 }
 
 static NMActStageReturn