Only globally synchronize open/close port methods on the native function call

src/main/c/Posix/jni/Android.mk

@@ -5,8 +5,8 @@ include $(CLEAR_VARS)
 LOCAL_MODULE := jSerialComm
 TARGET_OUT := ../../resources/Android/$(TARGET_ARCH_ABI)
 LOCAL_SRC_FILES := ../SerialPort_Posix.c ../PosixHelperFunctions.c
+LOCAL_CFLAGS := -fsigned-char -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0
 LOCAL_LDLIBS := -llog
-LOCAL_CFLAGS := -fsigned-char
 
 include $(BUILD_SHARED_LIBRARY)
 

src/main/c/Posix/jni/Application.mk

@@ -1,3 +1,4 @@
 APP_ABI := all
 APP_PLATFORM := android-21
 APP_MODULES := jSerialComm
+APP_CFLAGS += -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0

src/main/java/com/fazecast/jSerialComm/SerialPort.java

@@ -501,7 +501,9 @@ public final class SerialPort
 		serialPort.friendlyName = "User-Specified Port";
 		serialPort.portDescription = "User-Specified Port";
 		serialPort.portLocation = "0-0";
+		synchronized (SerialPort.class) {
 			serialPort.retrievePortDetails();
+		}
 		return serialPort;
 	}
 
@@ -583,9 +585,6 @@ public final class SerialPort
 	 * @return Whether the port was successfully opened with a valid configuration.
 	 */
 	public final synchronized boolean openPort(int safetySleepTime, int deviceSendQueueSize, int deviceReceiveQueueSize)
-	{
-		// Synchronize this method to the class scope as well
-        synchronized (SerialPort.class)
 	{
 		// Set the send/receive internal buffer sizes, and return true if already opened
 		safetySleepTimeMS = safetySleepTime;
@@ -630,15 +629,17 @@ public final class SerialPort
 			}
 		}
 
-			// Open the serial port and start an event-based listener if registered
+		// Natively open the serial port, and synchronize to the class scope since port enumeration methods are class-based,
-			if ((portHandle = openPortNative()) != 0)
+		//   and this method may alter or read a global class structure in native code
-			{
+		synchronized (SerialPort.class) {
-				if (serialEventListener != null)
+			portHandle = openPortNative();
+		}
+
+		// Start an event-based listener if registered and the port is open
+		if ((portHandle != 0) && (serialEventListener != null))
 			serialEventListener.startListening();
-			}
 		return (portHandle != 0);
 	}
-	}
 
 	/**
 	 * Opens this serial port for reading and writing with an optional delay time.
@@ -684,16 +685,20 @@ public final class SerialPort
 	 */
 	public final synchronized boolean closePort()
 	{
-		// Synchronize this method to the class scope as well
+		// Stop a registered event listener
-        synchronized (SerialPort.class)
-        {
 		if (serialEventListener != null)
 			serialEventListener.stopListening();
+
+		// Natively close the port, and synchronize to the class scope since port enumeration methods are class-based,
+		//   and this method may alter or read a global class structure in native code
 		if (portHandle != 0)
+		{
+			synchronized (SerialPort.class) {
 				portHandle = closePortNative(portHandle);
-			return (portHandle == 0);
 			}
 		}
+		return (portHandle == 0);
+	}
 
 	/**
 	 * Returns whether the port is currently open and available for communication.