From 94e084162590da9f61653224362e9da4ce8e3e13 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Fri, 11 Jul 2014 09:58:45 -0400
Subject: [PATCH] catch null vfork_exec_wrapper before it is too late

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

diff --git a/libs/pbd/system_exec.cc b/libs/pbd/system_exec.cc
index 811bd43d39..01c46aa9eb 100644
--- a/libs/pbd/system_exec.cc
+++ b/libs/pbd/system_exec.cc
@@ -805,6 +805,10 @@ SystemExec::start (int stderr_mode, const char *vfork_exec_wrapper)
 #else
 	signal(SIGPIPE, SIG_DFL);
 #endif
+	if (!vfork_exec_wrapper) {
+		error << _("Cannot start external process, no vfork wrapper") << endmsg;
+		return -1;
+	}
 
 	int good_fds[2] = { pok[1],  -1 };
 	close_allv(good_fds);