Add ability to retrieve DCD line status

build.gradle

@@ -5,7 +5,7 @@ apply plugin: 'osgi'
 
 group = 'com.fazecast'
 archivesBaseName = 'jSerialComm'
-version = '2.4.1'
+version = '2.4.2'
 ext.moduleName = 'com.fazecast.jSerialComm'
 
 assert hasProperty('java6Home'): "Set the property 'java6Home' in your gradle.properties file pointing to a Java 6 JDK installation"

src/main/c/Android/jni/SerialPort_Android.c

@@ -2,7 +2,7 @@
  * SerialPort_Android.c
  *
  *       Created on:  Mar 13, 2015
- *  Last Updated on:  Feb 11, 2019
+ *  Last Updated on:  Mar 07, 2019
  *           Author:  Will Hedgecock
  *
  * Copyright (C) 2012-2019 Fazecast, Inc.
@@ -671,4 +671,12 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getDSR(JNIEn
 	return (ioctl(serialPortFD, TIOCMGET, &modemBits) == 0) && (modemBits & TIOCM_LE);
 }
 
+JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getDCD(JNIEnv *env, jobject obj, jlong serialPortFD)
+{
+	if (serialPortFD <= 0)
+		return JNI_FALSE;
+	int modemBits = 0;
+	return (ioctl(serialPortFD, TIOCMGET, &modemBits) == 0) && (modemBits & TIOCM_CAR);
+}
+
 #endif

src/main/c/Android/jni/com_fazecast_jSerialComm_SerialPort.h

@@ -253,6 +253,14 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getCTS
 JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getDSR
   (JNIEnv *, jobject, jlong);
 
+/*
+ * Class:     com_fazecast_jSerialComm_SerialPort
+ * Method:    getDCD
+ * Signature: (J)Z
+ */
+JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getDCD
+  (JNIEnv *, jobject, jlong);
+
 #ifdef __cplusplus
 }
 #endif

src/main/c/Posix/SerialPort_Posix.c

@@ -2,10 +2,10 @@
  * SerialPort_Posix.c
  *
  *       Created on:  Feb 25, 2012
- *  Last Updated on:  Dec 07, 2018
+ *  Last Updated on:  Mar 07, 2019
  *           Author:  Will Hedgecock
  *
- * Copyright (C) 2012-2018 Fazecast, Inc.
+ * Copyright (C) 2012-2019 Fazecast, Inc.
  *
  * This file is part of jSerialComm.
  *
@@ -28,6 +28,7 @@
 #include <poll.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/file.h>
 #include <sys/ioctl.h>
 #include <sys/time.h>
 #include <termios.h>
@@ -247,35 +248,44 @@ JNIEXPORT jlong JNICALL Java_com_fazecast_jSerialComm_SerialPort_openPortNative(
 	int serialPortFD = -1;
 	if ((serialPortFD = open(portName, O_RDWR | O_NOCTTY | O_NONBLOCK)) > 0)
 	{
-		// Clear any serial port flags and set up raw, non-canonical port parameters
-		struct termios options = { 0 };
-		fcntl(serialPortFD, F_SETFL, 0);
-		tcgetattr(serialPortFD, &options);
-#if defined(__sun__)
-		options.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
-		options.c_oflag &= ~OPOST;
-		options.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
-		options.c_cflag &= ~(CSIZE | PARENB);
-		options.c_cflag |= CS8;
-#else
-		cfmakeraw(&options);
-#endif
-		if (!isDtrEnabled || !isRtsEnabled)
-			options.c_cflag &= ~HUPCL;
-		options.c_iflag |= BRKINT;
-		tcsetattr(serialPortFD, TCSANOW, &options);
-
-		// Configure the port parameters and timeouts
-		if (Java_com_fazecast_jSerialComm_SerialPort_configPort(env, obj, serialPortFD))
-			(*env)->SetBooleanField(env, obj, isOpenedField, JNI_TRUE);
-		else
+		// Ensure that multiple root users cannot access the device simultaneously
+		if (flock(serialPortFD, LOCK_EX | LOCK_NB) == -1)
 		{
-			// Close the port if there was a problem setting the parameters
-			ioctl(serialPortFD, TIOCNXCL);
-			tcdrain(serialPortFD);
 			while ((close(serialPortFD) == -1) && (errno != EBADF));
 			serialPortFD = -1;
-			(*env)->SetBooleanField(env, obj, isOpenedField, JNI_FALSE);
+		}
+		else
+		{
+			// Clear any serial port flags and set up raw, non-canonical port parameters
+			struct termios options = { 0 };
+			fcntl(serialPortFD, F_SETFL, 0);
+			tcgetattr(serialPortFD, &options);
+#if defined(__sun__)
+			options.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
+			options.c_oflag &= ~OPOST;
+			options.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
+			options.c_cflag &= ~(CSIZE | PARENB);
+			options.c_cflag |= CS8;
+#else
+			cfmakeraw(&options);
+#endif
+			if (!isDtrEnabled || !isRtsEnabled)
+				options.c_cflag &= ~HUPCL;
+			options.c_iflag |= BRKINT;
+			tcsetattr(serialPortFD, TCSANOW, &options);
+
+			// Configure the port parameters and timeouts
+			if (Java_com_fazecast_jSerialComm_SerialPort_configPort(env, obj, serialPortFD))
+				(*env)->SetBooleanField(env, obj, isOpenedField, JNI_TRUE);
+			else
+			{
+				// Close the port if there was a problem setting the parameters
+				ioctl(serialPortFD, TIOCNXCL);
+				tcdrain(serialPortFD);
+				while ((close(serialPortFD) == -1) && (errno != EBADF));
+				serialPortFD = -1;
+				(*env)->SetBooleanField(env, obj, isOpenedField, JNI_FALSE);
+			}
 		}
 	}
 
@@ -482,6 +492,7 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_closePortNat
 	tcsetattr(serialPortFD, TCSANOW, &options);
 
 	// Close the port
+	flock(serialPortFD, LOCK_UN);
 	while ((close(serialPortFD) == -1) && (errno != EBADF));
 	(*env)->SetLongField(env, obj, serialPortFdField, -1l);
 	return JNI_TRUE;
@@ -782,3 +793,11 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getDSR(JNIEn
 	int modemBits = 0;
 	return (ioctl(serialPortFD, TIOCMGET, &modemBits) == 0) && (modemBits & TIOCM_LE);
 }
+
+JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getDCD(JNIEnv *env, jobject obj, jlong serialPortFD)
+{
+	if (serialPortFD <= 0)
+		return JNI_FALSE;
+	int modemBits = 0;
+	return (ioctl(serialPortFD, TIOCMGET, &modemBits) == 0) && (modemBits & TIOCM_CAR);
+}

src/main/c/Windows/Makefile

@@ -3,7 +3,7 @@ COMPILE			= cl
 LINK			= link
 CFLAGS			= /c /O2 /GF /GL /MT /EHsc /fp:precise /J /nologo /TP
 LDFLAGS			= /DLL /LTCG /NOASSEMBLY /NOLOGO
-INCLUDES		= /I"$(JDK_HOME)/include" /I"$(JDK_HOME)/include/win32"
+INCLUDES		= /I"$(JDK_HOME)\include" /I"$(JDK_HOME)\include\win32"
 LIBRARIES		= Advapi32.lib SetupAPI.lib
 DELETE			= @del /q /f
 RMDIR			= @rd /q /s

src/main/c/Windows/SerialPort_Windows.c

@@ -2,10 +2,10 @@
  * SerialPort_Windows.c
  *
  *       Created on:  Feb 25, 2012
- *  Last Updated on:  Oct 31, 2018
+ *  Last Updated on:  Mar 07, 2019
  *           Author:  Will Hedgecock
  *
- * Copyright (C) 2012-2018 Fazecast, Inc.
+ * Copyright (C) 2012-2019 Fazecast, Inc.
  *
  * This file is part of jSerialComm.
  *
@@ -895,4 +895,13 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getDSR(JNIEn
 	return GetCommModemStatus(serialPortHandle, &modemStatus) && (modemStatus & MS_DSR_ON);
 }
 
+JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getDCD(JNIEnv *env, jobject obj, jlong serialPortFD)
+{
+	HANDLE serialPortHandle = (HANDLE)serialPortFD;
+	if (serialPortHandle == INVALID_HANDLE_VALUE)
+		return JNI_FALSE;
+	DWORD modemStatus = 0;
+	return GetCommModemStatus(serialPortHandle, &modemStatus) && (modemStatus & MS_RLSD_ON);
+}
+
 #endif

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

@@ -2,7 +2,7 @@
  * SerialPort.java
  *
  *       Created on:  Feb 25, 2012
- *  Last Updated on:  Feb 11, 2019
+ *  Last Updated on:  Mar 07, 2019
  *           Author:  Will Hedgecock
  *
  * Copyright (C) 2012-2019 Fazecast, Inc.
@@ -42,7 +42,7 @@ import java.util.Date;
  * This class provides native access to serial ports and devices without requiring external libraries or tools.
  *
  * @author Will Hedgecock <will.hedgecock@fazecast.com>
- * @version 2.4.1
+ * @version 2.4.2
  * @see java.io.InputStream
  * @see java.io.OutputStream
  */
@@ -520,6 +520,7 @@ public final class SerialPort
 	private final native boolean preclearDTR();							// Clear DTR line to 0 prior to opening
 	private final native boolean getCTS(long portHandle);				// Returns whether the CTS signal is 1
 	private final native boolean getDSR(long portHandle);				// Returns whether the DSR signal is 1
+	private final native boolean getDCD(long portHandle);				// Returns whether the DCD signal is 1
 
 	/**
 	 * Returns the number of bytes available without blocking if {@link #readBytes(byte[], long)} were to be called immediately
@@ -663,6 +664,12 @@ public final class SerialPort
 	 * @return Whether or not the DSR line is asserted.
 	 */
 	public final boolean getDSR() { return getDSR(portHandle); }
+	
+	/**
+	 * Returns whether the DCD line is currently asserted.
+	 * @return Whether or not the DCD line is asserted.
+	 */
+	public final boolean getDCD() { return getDCD(portHandle); }
 
 	// Default Constructor
 	private SerialPort() {}

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

@@ -31,7 +31,7 @@ import java.util.EventListener;
  * This interface must be implemented to enable simple event-based serial port I/O.
  * 
  * @author Will Hedgecock <will.hedgecock@fazecast.com>
- * @version 2.4.1
+ * @version 2.4.2
  * @see java.util.EventListener
  */
 public interface SerialPortDataListener extends EventListener

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

@@ -31,7 +31,7 @@ import java.util.EventObject;
  * This class describes an asynchronous serial port event.
  * 
  * @author Will Hedgecock <will.hedgecock@fazecast.com>
- * @version 2.4.1
+ * @version 2.4.2
  * @see java.util.EventObject
  */
 public final class SerialPortEvent extends EventObject

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

@@ -31,7 +31,7 @@ import java.io.IOException;
  * This class describes a serial port IO exception.
  * 
  * @author Will Hedgecock <will.hedgecock@fazecast.com>
- * @version 2.4.1
+ * @version 2.4.2
  * @see java.io.IOException
  */
 public final class SerialPortIOException extends IOException

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

@@ -31,7 +31,7 @@ package com.fazecast.jSerialComm;
  * <i>Note</i>: Using this interface will negate any serial port read timeout settings since they make no sense in an asynchronous context.
  * 
  * @author Will Hedgecock &lt;will.hedgecock@fazecast.com&gt;
- * @version 2.4.1
+ * @version 2.4.2
  * @see com.fazecast.jSerialComm.SerialPortDataListener
  * @see java.util.EventListener
  */

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

@@ -31,7 +31,7 @@ import java.io.InterruptedIOException;
  * This class describes a serial port timeout exception.
  * 
  * @author Will Hedgecock <will.hedgecock@fazecast.com>
- * @version 2.4.1
+ * @version 2.4.2
  * @see java.io.InterruptedIOException
  */
 public final class SerialPortTimeoutException extends InterruptedIOException