From 427d6a7dca4e9960ddd3e53b5c9879aa17ced6b4 Mon Sep 17 00:00:00 2001
From: john30 <ebusd@ebusd.eu>
Date: Sun, 22 Nov 2015 13:54:18 +0100
Subject: [PATCH] exclusively lock serial device to prevent simultaneous
 access, fix for closing serial device that is no tty

---
 src/lib/ebus/device.cpp | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/lib/ebus/device.cpp b/src/lib/ebus/device.cpp
index f7cd7d8c..b34a316b 100644
--- a/src/lib/ebus/device.cpp
+++ b/src/lib/ebus/device.cpp
@@ -28,6 +28,7 @@
 #include <fcntl.h>
 #include <fstream>
 #include <sys/ioctl.h>
+#include <sys/file.h>
 #include <errno.h>
 
 #ifdef HAVE_PPOLL
@@ -214,8 +215,17 @@ result_t SerialDevice::open()
 	// open file descriptor
 	m_fd = ::open(m_name, O_RDWR | O_NOCTTY);
 
-	if (m_fd < 0 || isatty(m_fd) == 0)
+	if (m_fd < 0)
 		return RESULT_ERR_NOTFOUND;
+	if (isatty(m_fd) == 0) {
+		close();
+		return RESULT_ERR_NOTFOUND;
+	}
+
+	if (flock(m_fd, LOCK_EX|LOCK_NB)) {
+		close();
+		return RESULT_ERR_DEVICE;
+	}
 
 	// save current settings
 	tcgetattr(m_fd, &m_oldSettings);