From 55a79fbe96a87183fa4e11049eb161943636b1dd Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 22 Sep 2007 10:59:03 +0000
Subject: [PATCH] Use dladdr instead of backtrace_symbols in Backtrace::create
 (both are GNU-specific anyway) Fix an error handling bug in demangle Output
 backtrace for uncaught exceptions if one exists

---
 Build                       |  6 ++++++
 source/core/application.cpp | 16 ++++++++++++++++
 source/debug/backtrace.cpp  | 25 ++++++++++++++++++++-----
 source/debug/backtrace.h    |  3 ++-
 source/debug/demangle.cpp   |  9 ++++++++-
 5 files changed, 52 insertions(+), 7 deletions(-)

diff --git a/Build b/Build
index 03dc8d2..d7dfac8 100644
--- a/Build
+++ b/Build
@@ -1,3 +1,5 @@
+/* $Id$ */
+
 package "mspcore"
 {
 	version "0.1";
@@ -7,6 +9,10 @@ package "mspcore"
 	if "arch!=win32"
 	{
 		require "pthread";
+		build_info
+		{
+			library "dl";
+		};
 	};
 
 	feature "exception_backtrace" "Generate a backtrace when an exception is thrown.";
diff --git a/source/core/application.cpp b/source/core/application.cpp
index a498023..3a663db 100644
--- a/source/core/application.cpp
+++ b/source/core/application.cpp
@@ -6,6 +6,7 @@ Distributed under the LGPL
 */
 #include <signal.h>
 #include <iostream>
+#include "../debug/backtrace.h"
 #include "../debug/demangle.h"
 #include "../time/units.h"
 #include "../time/utils.h"
@@ -60,6 +61,21 @@ int Application::run(int argc, char **argv)
 		cerr<<"An uncaught exception occurred.\n";
 		cerr<<"  type:   "<<Debug::demangle(typeid(e).name())<<'\n';
 		cerr<<"  what(): "<<e.what()<<'\n';
+
+		const Exception *exc=dynamic_cast<const Exception *>(&e);
+		if(exc && !exc->get_backtrace().get_frames().empty())
+		{
+			cerr<<"  backtrace:\n";
+			const Debug::Backtrace::FrameSeq &frames=exc->get_backtrace().get_frames();
+			for(Debug::Backtrace::FrameSeq::const_iterator i=frames.begin(); i!=frames.end(); ++i)
+			{
+				cerr<<"    "<<i->address;
+				if(!i->symbol.empty())
+					cerr<<" in "<<i->symbol;
+				cerr<<" from "<<i->file<<'\n';
+			}
+		}
+
 		delete app_;
 		return 124;
 	}
diff --git a/source/debug/backtrace.cpp b/source/debug/backtrace.cpp
index c0bfd9d..643fdf2 100644
--- a/source/debug/backtrace.cpp
+++ b/source/debug/backtrace.cpp
@@ -5,9 +5,11 @@ Copyright © 2007 Mikko Rasa, Mikkosoft Productions
 Distributed under the LGPL
 */
 #ifndef WIN32
+#include <dlfcn.h>
 #include <execinfo.h>
 #endif
 #include "backtrace.h"
+#include "demangle.h"
 
 using namespace std;
 
@@ -20,13 +22,26 @@ Backtrace Backtrace::create()
 	void *addresses[50];
 	int count=::backtrace(addresses, 50);
 
-	char **symbols=backtrace_symbols(addresses, count);
+	//char **symbols=backtrace_symbols(addresses, count);
 
 	Backtrace bt;
+	Dl_info dli;
 	for(int i=0; i<count; ++i)
-		bt.frames.push_back(StackFrame(addresses[i], symbols[i]));
-
-	free(symbols);
+	{
+		StackFrame frame;
+		frame.address=addresses[i];
+		if(dladdr(addresses[i], &dli))
+		{
+			frame.file=dli.dli_fname;
+			if(dli.dli_sname)
+				frame.symbol=demangle(dli.dli_sname);
+		}
+		else
+			frame.file="<unknown>";
+		bt.frames.push_back(frame);
+	}
+
+	//free(symbols);
 
 	return bt;
 #else
@@ -38,7 +53,7 @@ ostream &operator<<(ostream &out, const Backtrace &bt)
 {
 	const Backtrace::FrameSeq &frames=bt.get_frames();
 	for(Backtrace::FrameSeq::const_iterator i=frames.begin(); i!=frames.end(); ++i)
-		out<<i->address<<" in "<<i->symbol<<'\n';
+		out<<i->address<<" in "<<i->symbol<<" from "<<i->file<<'\n';
 
 	return out;
 }
diff --git a/source/debug/backtrace.h b/source/debug/backtrace.h
index c570ce5..9715df0 100644
--- a/source/debug/backtrace.h
+++ b/source/debug/backtrace.h
@@ -20,9 +20,10 @@ public:
 	struct StackFrame
 	{
 		void *address;
+		std::string file;
 		std::string symbol;
 
-		StackFrame(void *a, const std::string &s): address(a), symbol(s) { }
+		//StackFrame(void *a, const std::string &s): address(a), symbol(s) { }
 	};
 	typedef std::list<StackFrame> FrameSeq;
 
diff --git a/source/debug/demangle.cpp b/source/debug/demangle.cpp
index 460410e..9ed6e95 100644
--- a/source/debug/demangle.cpp
+++ b/source/debug/demangle.cpp
@@ -18,8 +18,15 @@ string demangle(const string &sym)
 #ifdef __GNUC__
 	int status;
 	char *dm=abi::__cxa_demangle(sym.c_str(), 0, 0, &status);
-	string result(dm);
+	
+	string result;
+	if(status==0)
+		result=dm;
+	else
+		result=sym;
+	
 	free(dm);
+
 	return result;
 #else
 	return sym;
-- 
2.43.0