Use backtrace_symbols() when printing stack traces on FreeBSD

Unfortunately, the symbol resolution of boost::stacktrace is broken on
FreeBSD, therefore fall back to using backtrace_symbols() to print the
stack trace saved by Boost.

Additionally, -D_GNU_SOURCE is required on FreeBSD for the
_Unwind_Backtrace function used by boost::stacktrace.

CMakeLists.txt

@@ -367,6 +367,15 @@ if(HAVE_LIBEXECINFO)
   set(HAVE_BACKTRACE_SYMBOLS TRUE)
 endif()
 
+if(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
+  set(ICINGA2_STACKTRACE_USE_BACKTRACE_SYMBOLS TRUE)
+  add_definitions(-D_GNU_SOURCE)
+endif()
+
+if(ICINGA2_STACKTRACE_USE_BACKTRACE_SYMBOLS AND NOT HAVE_BACKTRACE_SYMBOLS)
+  message(FATAL_ERROR "ICINGA2_STACKTRACE_USE_BACKTRACE_SYMBOLS is set but backtrace_symbols() was not found")
+endif()
+
 if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   exec_program(${CMAKE_CXX_COMPILER}
     ARGS -dumpversion

config.h.cmake

@@ -12,6 +12,7 @@
 #cmakedefine HAVE_SYSTEMD
 
 #cmakedefine ICINGA2_UNITY_BUILD
+#cmakedefine ICINGA2_STACKTRACE_USE_BACKTRACE_SYMBOLS
 
 #define ICINGA_CONFIGDIR "${ICINGA2_FULL_CONFIGDIR}"
 #define ICINGA_DATADIR "${ICINGA2_FULL_DATADIR}"

lib/base/CMakeLists.txt

@@ -64,6 +64,7 @@ set(base_SOURCES
   shared-object.hpp
   singleton.hpp
   socket.cpp socket.hpp
+  stacktrace.cpp stacktrace.hpp
   statsfunction.hpp
   stdiostream.cpp stdiostream.hpp
   stream.cpp stream.hpp

lib/base/application.cpp

@@ -2,6 +2,7 @@
 
 #include "base/application.hpp"
 #include "base/application-ti.cpp"
+#include "base/stacktrace.hpp"
 #include "base/timer.hpp"
 #include "base/logger.hpp"
 #include "base/exception.hpp"
@@ -763,7 +764,7 @@ void Application::SigAbrtHandler(int)
 
 		DisplayInfoMessage(ofs);
 
-		ofs << "\nStacktrace:\n" << boost::stacktrace::stacktrace() << "\n";
+		ofs << "\nStacktrace:\n" << StackTraceFormatter(boost::stacktrace::stacktrace()) << "\n";
 
 		DisplayBugMessage(ofs);
 
@@ -954,7 +955,7 @@ LONG CALLBACK Application::SEHUnhandledExceptionFilter(PEXCEPTION_POINTERS exi)
 		<< "  Flags: "   << exi->ExceptionRecord->ExceptionFlags   << "\n";
 	ofs.flags(savedflags);
 
-	ofs << "\nStacktrace:\n" << boost::stacktrace::stacktrace() << "\n";
+	ofs << "\nStacktrace:\n" << StackTraceFormatter(boost::stacktrace::stacktrace()) << "\n";
 
 	DisplayBugMessage(ofs);
 

lib/base/exception.cpp

@@ -1,6 +1,7 @@
 /* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
 
 #include "base/exception.hpp"
+#include "base/stacktrace.hpp"
 #include <boost/thread/tss.hpp>
 #include <utility>
 
@@ -248,7 +249,7 @@ String icinga::DiagnosticInformation(const std::exception& ex, bool verbose, boo
 		}
 
 		if (st && !st->empty()) {
-			result << "\nStacktrace:\n" << *st;
+			result << "\nStacktrace:\n" << StackTraceFormatter(*st);
 		}
 	}
 

lib/base/stacktrace.cpp

@@ -0,0 +1,36 @@
+/* Icinga 2 | (c) 2020 Icinga GmbH | GPLv2+ */
+
+#include <base/i2-base.hpp>
+#include "base/stacktrace.hpp"
+#include <iostream>
+#include <iomanip>
+#include <vector>
+
+#ifdef HAVE_BACKTRACE_SYMBOLS
+#	include <execinfo.h>
+#endif /* HAVE_BACKTRACE_SYMBOLS */
+
+using namespace icinga;
+
+std::ostream &icinga::operator<<(std::ostream &os, const StackTraceFormatter &f)
+{
+	const boost::stacktrace::stacktrace &stack = f.m_Stack;
+
+#ifdef ICINGA2_STACKTRACE_USE_BACKTRACE_SYMBOLS
+	std::vector<void *> addrs;
+	addrs.reserve(stack.size());
+	std::transform(stack.begin(), stack.end(), std::back_inserter(addrs), [](const boost::stacktrace::frame &f) {
+		return const_cast<void *>(f.address());
+	});
+
+	char **symbols = backtrace_symbols(addrs.data(), addrs.size());
+	for (size_t i = 0; i < addrs.size(); i++) {
+		os << std::setw(2) << i << "# " << symbols[i] << std::endl;
+	}
+	std::free(symbols);
+#else /* ICINGA2_STACKTRACE_USE_BACKTRACE_SYMBOLS */
+	os << stack;
+#endif /* ICINGA2_STACKTRACE_USE_BACKTRACE_SYMBOLS */
+
+	return os;
+}

lib/base/stacktrace.hpp

@@ -0,0 +1,25 @@
+/* Icinga 2 | (c) 2020 Icinga GmbH | GPLv2+ */
+
+#ifndef STACKTRACE_H
+#define STACKTRACE_H
+
+#include <boost/stacktrace.hpp>
+
+namespace icinga
+{
+
+class StackTraceFormatter {
+public:
+	StackTraceFormatter(const boost::stacktrace::stacktrace &stack) : m_Stack(stack) {}
+
+private:
+	const boost::stacktrace::stacktrace &m_Stack;
+
+	friend std::ostream &operator<<(std::ostream &os, const StackTraceFormatter &f);
+};
+
+std::ostream& operator<<(std::ostream& os, const StackTraceFormatter &f);
+
+}
+
+#endif /* STACKTRACE_H */