From 4cb16b105f5dbd7c2a0cbc703aab3e64359c99c8 Mon Sep 17 00:00:00 2001
From: Phil Taylor <phil@m0vse.uk>
Date: Wed, 22 Sep 2021 10:59:03 +0100
Subject: [PATCH] Add keepalive for linux/mac pty

---
 pttyhandler.cpp | 7 +++++++
 pttyhandler.h   | 1 +
 2 files changed, 8 insertions(+)

diff --git a/pttyhandler.cpp b/pttyhandler.cpp
index 6b4350d..36a5204 100644
--- a/pttyhandler.cpp
+++ b/pttyhandler.cpp
@@ -73,6 +73,9 @@ void pttyHandler::openPort()
         // we're good!
         qInfo(logSerial()) << "Opened pseudoterminal, slave name :" << ptsname(ptfd);
 
+        // Open the slave device to keep alive.
+        ptKeepAlive = open(ptsnamd(ptfd), O_RDONLY);
+
         ptReader = new QSocketNotifier(ptfd, QSocketNotifier::Read, this);
         connect(ptReader, &QSocketNotifier::activated,
                 this, &pttyHandler::receiveDataIn);
@@ -283,6 +286,10 @@ void pttyHandler::closePort()
     {
         QFile::remove(portName);
     }
+
+    if (ptKeepAlive > 0) {
+        close(ptKeepAlive);
+    }
 #endif
     isConnected = false;
 }
diff --git a/pttyhandler.h b/pttyhandler.h
index 14c9bfc..73aa80e 100644
--- a/pttyhandler.h
+++ b/pttyhandler.h
@@ -62,6 +62,7 @@ private:
     bool rolledBack;
 
     int ptfd; // pseudo-terminal file desc.
+    int ptKeepAlive=0; // Used to keep the pty alive after client disconects.
     bool havePt;
     QString ptDevSlave;