From 0c2d95b08f1310533aa14604f7745be8681d10ec Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Thu, 28 Mar 2013 23:32:02 +0100
Subject: [PATCH] vtl: fix possible race condition when terminating external
 program

---
 gtk2_ardour/system_exec.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gtk2_ardour/system_exec.cc b/gtk2_ardour/system_exec.cc
index 889b1565ad..44fed48c12 100644
--- a/gtk2_ardour/system_exec.cc
+++ b/gtk2_ardour/system_exec.cc
@@ -409,6 +409,7 @@ SystemExec::make_argp(std::string args) {
 void
 SystemExec::terminate ()
 {
+	::pthread_mutex_lock(&write_lock);
 	close_stdin();
 	if (pid) {
 		::usleep(100000);
@@ -428,6 +429,8 @@ SystemExec::terminate ()
 
 	wait();
 	if (thread_active) pthread_join(thread_id_tt, NULL);
+	thread_active = false;
+	::pthread_mutex_unlock(&write_lock);
 }
 
 int
@@ -626,6 +629,7 @@ SystemExec::close_stdin()
 	::close(pin[1]);
 	::close(pout[0]);
 	::close(pout[1]);
+	pin[1] = - 1; // mark as closed
 }
 
 int