* #18668: daemon: only join threads that have been created

If you try and join a NULL thread, you will segfault.

daemon/src/eventthread.cpp

@@ -31,12 +31,13 @@
 #include "eventthread.h"
 #include "voiplink.h"
 
-EventThread::EventThread(VoIPLink *link) : link_(link)
+EventThread::EventThread(VoIPLink *link) : link_(link), thread_(0)
 {}
 
 EventThread::~EventThread()
 {
-    pthread_join(thread_, NULL);
+    if (thread_)
+        pthread_join(thread_, NULL);
 }
 
 void EventThread::start()

daemon/src/video/video_receive_thread.cpp

@@ -223,7 +223,7 @@ VideoReceiveThread::VideoReceiveThread(const std::string &id, const std::map<str
     avioContext_(avio_alloc_context(sdpBuffer_.get(), SDP_BUFFER_SIZE, 0,
                                     reinterpret_cast<void*>(static_cast<std::istream*>(&stream_)),
                                     &readFunction, 0, 0), &av_free),
-    thread_()
+    thread_(0)
 {
     interruptCb_.callback = interruptCb;
     interruptCb_.opaque = this;
@@ -347,7 +347,8 @@ VideoReceiveThread::~VideoReceiveThread()
     set_false_atomic(&threadRunning_);
     Manager::instance().getVideoControls()->stoppedDecoding(id_, sink_.openedName());
     // waits for the run() method (in separate thread) to return
-    pthread_join(thread_, NULL);
+    if (thread_)
+        pthread_join(thread_, NULL);
 }
 
 void VideoReceiveThread::setRequestKeyFrameCallback(void (*cb)(const std::string &))

daemon/src/video/video_send_thread.cpp

@@ -347,7 +347,7 @@ VideoSendThread::VideoSendThread(const std::string &id, const std::map<string, s
     interruptCb_(),
     threadRunning_(false),
     forceKeyFrame_(0),
-    thread_(),
+    thread_(0),
     frameNumber_(0)
 {
     interruptCb_.callback = interruptCb;
@@ -562,7 +562,8 @@ VideoSendThread::~VideoSendThread()
 {
     set_false_atomic(&threadRunning_);
     Manager::instance().getVideoControls()->stoppedDecoding(id_, sink_.openedName());
-    pthread_join(thread_, NULL);
+    if (thread_)
+        pthread_join(thread_, NULL);
 }
 
 void VideoSendThread::forceKeyFrame()

daemon/src/video/video_v4l2_list.cpp

@@ -67,7 +67,7 @@ static int is_v4l2(struct udev_device *dev)
 }
 
 VideoV4l2ListThread::VideoV4l2ListThread() : devices_(),
-    thread_(), mutex_(), udev_(0),
+    thread_(0), mutex_(), udev_(0),
     udev_mon_(0), probing_(false)
 {
     pthread_mutex_init(&mutex_, NULL);
@@ -214,7 +214,8 @@ start:
 VideoV4l2ListThread::~VideoV4l2ListThread()
 {
     probing_ = false;
-    pthread_join(thread_, NULL);
+    if (thread_)
+        pthread_join(thread_, NULL);
     if (udev_mon_)
         udev_monitor_unref(udev_mon_);
     if (udev_)