multi-arfcn, trx: allocate threads on heap and fix thread release

The underlying pthread of the Thread object isn't created until
Thread::start(). If the Thread object is contructed, but not
started, then the destructor will fail with a variety of
unpredictable errors such as the following or double free() in
certain cases.

Program received signal SIGSEGV, Segmentation fault.
__GI___libc_free (mem=0x3811abed3e946178) at malloc.c:2972
2972      if (chunk_is_mmapped(p))

If the Thread object is stack allocated, but start() isn't called,
destructor is guaranteed to run and will fail. The previous
approach was to dynamically allocate threads, but not free them,
thus avoiding memory errors, but creating memory leaks.

To get around this limitation, dynamically allocate Thread objects
and initialize with NULL. Then allocate immediately prior to start
such that pthread allocation is tied to the Thread object
constructor. Deallocation can check that the Thread pointer is
valid through NULL or other tracking methods.

Signed-off-by: Thomas Tsou <ttsou@vt.edu>

1 files changed, 5 insertions, 2 deletions

diff --git a/Transceiver52M/DriveLoop.cpp b/Transceiver52M/DriveLoop.cpp
index c080c12..7e250f8 100644
--- a/Transceiver52M/DriveLoop.cpp
+++ b/Transceiver52M/DriveLoop.cpp
@@ -29,8 +29,7 @@ DriveLoop::DriveLoop(int wSamplesPerSymbol,
                      GSM::Time wTransmitLatency,
                      RadioInterface *wRadioInterface)
 {
-  mRadioDriveLoopThread = new Thread(32768);
-
+  mRadioDriveLoopThread = NULL;
   mSamplesPerSymbol = wSamplesPerSymbol;
   mRadioInterface = wRadioInterface;
 
@@ -70,6 +69,9 @@ DriveLoop::DriveLoop(int wSamplesPerSymbol,
 
 DriveLoop::~DriveLoop()
 {
+  if (mRadioDriveLoopThread)
+    delete mRadioDriveLoopThread;
+
   delete gsmPulse;
   sigProcLibDestroy();
 }
@@ -77,6 +79,7 @@ DriveLoop::~DriveLoop()
 void DriveLoop::start()
 {
   mOn = true;
+  mRadioDriveLoopThread = new Thread(32768);
   mRadioDriveLoopThread->start((void * (*)(void*))RadioDriveLoopAdapter, (void*) this);
 }