From c742c292b6617c08695367fbd1de9f21e942ffd4 Mon Sep 17 00:00:00 2001
From: Stephen Birarda <commit@birarda.com>
Date: Mon, 6 May 2013 15:29:21 -0700
Subject: [PATCH] have the audio mixer output a stacktrace when it crashes

---
 audio-mixer/src/main.cpp            | 13 ++++++++-----
 libraries/shared/src/Stacktrace.cpp | 27 +++++++++++++++++++++++++++
 libraries/shared/src/Stacktrace.h   | 16 ++++++++++++++++
 3 files changed, 51 insertions(+), 5 deletions(-)
 create mode 100644 libraries/shared/src/Stacktrace.cpp
 create mode 100644 libraries/shared/src/Stacktrace.h

diff --git a/audio-mixer/src/main.cpp b/audio-mixer/src/main.cpp
index 5ab7f621df..06c2300315 100644
--- a/audio-mixer/src/main.cpp
+++ b/audio-mixer/src/main.cpp
@@ -16,10 +16,13 @@
 #include <errno.h>
 #include <fstream>
 #include <limits>
+
 #include <AgentList.h>
 #include <AgentTypes.h>
 #include <SharedUtil.h>
 #include <StdDev.h>
+#include <Stacktrace.h>
+
 #include "AudioRingBuffer.h"
 #include "PacketHeaders.h"
 
@@ -71,8 +74,7 @@ void plateauAdditionOfSamples(int16_t &mixSample, int16_t sampleToAdd) {
     mixSample = normalizedSample;    
 }
 
-void *sendBuffer(void *args)
-{
+void *sendBuffer(void *args) {
     int sentBytes;
     int nextFrame = 0;
     timeval startTime;
@@ -255,11 +257,12 @@ void attachNewBufferToAgent(Agent *newAgent) {
     }
 }
 
-int main(int argc, const char * argv[])
-{
-    AgentList* agentList = AgentList::createInstance(AGENT_TYPE_AUDIO_MIXER, MIXER_LISTEN_PORT);
+int main(int argc, const char* argv[]) {
+    signal(SIGSEGV, printStacktrace);
     setvbuf(stdout, NULL, _IOLBF, 0);
     
+    AgentList* agentList = AgentList::createInstance(AGENT_TYPE_AUDIO_MIXER, MIXER_LISTEN_PORT);
+    
     ssize_t receivedBytes = 0;
     
     agentList->linkedDataCreateCallback = attachNewBufferToAgent;
diff --git a/libraries/shared/src/Stacktrace.cpp b/libraries/shared/src/Stacktrace.cpp
new file mode 100644
index 0000000000..d53fc016ec
--- /dev/null
+++ b/libraries/shared/src/Stacktrace.cpp
@@ -0,0 +1,27 @@
+//
+//  Stacktrace.cpp
+//  hifi
+//
+//  Created by Stephen Birarda on 5/6/13.
+//
+//
+
+#include <signal.h>
+#include <stdio.h>
+#include <execinfo.h>
+
+#include "Stacktrace.h"
+
+const int NUMBER_OF_STACK_ENTRIES = 20;
+
+void printStacktrace(int signal) {
+    void* array[NUMBER_OF_STACK_ENTRIES];
+    
+    // get void*'s for all entries on the stack
+    size_t size = backtrace(array, NUMBER_OF_STACK_ENTRIES);
+    
+    // print out all the frames to stderr
+    fprintf(stderr, "Error: signal %d:\n", signal);
+    backtrace_symbols_fd(array, size, 2);
+    exit(1);
+}
\ No newline at end of file
diff --git a/libraries/shared/src/Stacktrace.h b/libraries/shared/src/Stacktrace.h
new file mode 100644
index 0000000000..c58422ea0c
--- /dev/null
+++ b/libraries/shared/src/Stacktrace.h
@@ -0,0 +1,16 @@
+//
+//  Stacktrace.h
+//  hifi
+//
+//  Created by Stephen Birarda on 5/6/13.
+//
+//
+
+#ifndef __hifi__Stacktrace__
+#define __hifi__Stacktrace__
+
+#include <iostream>
+
+void printStacktrace(int signal);
+
+#endif /* defined(__hifi__Stacktrace__) */