commander: do not reboot on USB disconnect when armed

Signed-off-by: Andrei Korigodski <akorigod@gmail.com>

src/modules/commander/Commander.cpp

@@ -197,6 +197,8 @@ void print_reject_arm(const char *msg);
 
 void print_status();
 
+bool shutdown_if_allowed();
+
 transition_result_t arm_disarm(bool arm, orb_advert_t *mavlink_log_pub, const char *armedBy);
 
 /**
@@ -521,6 +523,13 @@ void print_status()
 	PX4_INFO("arming: %s", arming_state_names[status.arming_state]);
 }
 
+bool shutdown_if_allowed()
+{
+	return TRANSITION_DENIED != arming_state_transition(&status, safety, vehicle_status_s::ARMING_STATE_REBOOT,
+			&armed, false /* fRunPreArmChecks */, &mavlink_log_pub, &status_flags, arm_requirements,
+			hrt_elapsed_time(&commander_boot_timestamp));
+}
+
 transition_result_t arm_disarm(bool arm, orb_advert_t *mavlink_log_pub_local, const char *armedBy)
 {
 	transition_result_t arming_res = TRANSITION_NOT_CHANGED;
@@ -1511,7 +1520,7 @@ Commander::run()
 				}
 
 				/* if the USB hardware connection went away, reboot */
-				if (status_flags.usb_connected && !system_power.usb_connected) {
+				if (status_flags.usb_connected && !system_power.usb_connected && shutdown_if_allowed()) {
 					/*
 					 * apparently the USB cable went away but we are still powered,
 					 * so lets reset to a classic non-usb state.