Ensure port still exists when trying to gain elevated access

src/main/c/Posix/PosixHelperFunctions.c

@@ -1640,10 +1640,13 @@ int verifyAndSetUserPortGroup(const char *portFile)
 	// Attempt to acquire access if not available
 	if (!userCanAccess)
 	{
-		// Check if the user is part of the group that owns the port
+		// Ensure that the port still exists
 		struct stat fileStats;
+		if (stat(portFile, &fileStats) == 0)
+		{
+			// Check if the user is part of the group that owns the port
 			gid_t *userGroups = (gid_t*)malloc(numGroups * sizeof(gid_t));
-		if ((stat(portFile, &fileStats) == 0) && (getgroups(numGroups, userGroups) >= 0))
+			if (getgroups(numGroups, userGroups) >= 0)
 				for (int i = 0; i < numGroups; ++i)
 					if (userGroups[i] == fileStats.st_gid)
 					{
@@ -1672,6 +1675,7 @@ int verifyAndSetUserPortGroup(const char *portFile)
 			free(addUserToGroupCmd);
 			free(userGroups);
 		}
+	}
 
 	// Return whether the user can currently access the serial port
 	return userCanAccess;

src/test/java/com/fazecast/jSerialComm/SerialPortTest.java

@@ -268,18 +268,22 @@ public class SerialPortTest
 		ubxPort.addDataListener(new SerialPortDataListener() {
 			@Override
 			public int getListeningEvents() { return SerialPort.LISTENING_EVENT_PARITY_ERROR | SerialPort.LISTENING_EVENT_DATA_WRITTEN | SerialPort.LISTENING_EVENT_BREAK_INTERRUPT |
-					SerialPort.LISTENING_EVENT_CARRIER_DETECT | SerialPort.LISTENING_EVENT_CTS | SerialPort.LISTENING_EVENT_DSR | SerialPort.LISTENING_EVENT_RING_INDICATOR | 
+					SerialPort.LISTENING_EVENT_CARRIER_DETECT | SerialPort.LISTENING_EVENT_CTS | SerialPort.LISTENING_EVENT_DSR | SerialPort.LISTENING_EVENT_RING_INDICATOR | SerialPort.LISTENING_EVENT_PORT_DISCONNECTED |
 					SerialPort.LISTENING_EVENT_FRAMING_ERROR | SerialPort.LISTENING_EVENT_FIRMWARE_OVERRUN_ERROR | SerialPort.LISTENING_EVENT_SOFTWARE_OVERRUN_ERROR | SerialPort.LISTENING_EVENT_DATA_AVAILABLE; }
 			@Override
 			public void serialEvent(SerialPortEvent event)
 			{
-				System.out.println("Received event type: " + event.getEventType());
 				if (event.getEventType() == SerialPort.LISTENING_EVENT_DATA_AVAILABLE)
 				{
+					System.out.println("Received event type: LISTENING_EVENT_DATA_AVAILABLE");
 					byte[] buffer = new byte[event.getSerialPort().bytesAvailable()];
 					event.getSerialPort().readBytes(buffer, buffer.length);
 					System.out.println("   Reading " + buffer.length + " bytes");
 				}
+				else if (event.getEventType() == SerialPort.LISTENING_EVENT_PORT_DISCONNECTED)
+					System.out.println("Received event type: LISTENING_EVENT_PORT_DISCONNECTED");
+				else
+					System.out.println("Received event type: " + event.getEventType());
 			}
 		});
 		try { Thread.sleep(5000); } catch (Exception e) {}
@@ -311,29 +315,6 @@ public class SerialPortTest
 		ubxPort.removeDataListener();
 		System.out.println("\nClosing " + ubxPort.getDescriptivePortName() + ": " + ubxPort.closePort());
 
-		/*System.out.println("\nPhysically unplug device within the next 10 seconds to see if the disconnect event fires...");
-		ubxPort.addDataListener(new SerialPortDataListener() {
-			@Override
-			public int getListeningEvents() { return SerialPort.LISTENING_EVENT_PORT_DISCONNECTED | SerialPort.LISTENING_EVENT_DATA_AVAILABLE; }
-			@Override
-			public void serialEvent(SerialPortEvent event)
-			{
-				if (event.getEventType() == SerialPort.LISTENING_EVENT_DATA_AVAILABLE)
-				{
-					System.out.println("Received event type: LISTENING_EVENT_DATA_AVAILABLE");
-					byte[] buffer = new byte[event.getSerialPort().bytesAvailable()];
-					event.getSerialPort().readBytes(buffer, buffer.length);
-					System.out.println("   Reading " + buffer.length + " bytes");
-				}
-				else
-				{
-					System.out.println("Received event type: LISTENING_EVENT_PORT_DISCONNECTED");
-				}
-			}
-		});
-		try { Thread.sleep(10000); } catch (Exception e) {}
-		ubxPort.closePort();*/
-
 		/*System.out.println("\n\nAttempting to read from two serial ports simultaneously\n");
 		System.out.println("\nAvailable Ports:\n");
 		for (int i = 0; i < ports.length; ++i)