android native stack backtrace

BackTraceUtils.cpp

#ifndef BACKTRACE_UTILS_h
#define BACKTRACE_UTILS_h

// ref: http://stackoverflow.com/questions/8115192/android-ndk-getting-the-backtrace

#include <cstdio>
#include <ostream>
#include <sstream>

size_t captureBacktrace(void** buffer, size_t max);
void dumpBacktrace(std::ostream& os, void** buffer, size_t count);
/** usage:
  std::ostringstream oss;
  getBacktrace(oss, 30);
  __android_log_print(ANDROID_LOG_INFO, "app_name", "%s", oss.str().c_str());
*/
void getBacktrace(std::ostringstream& os, const size_t max=30);

#endif


#include <iomanip>
#include <unwind.h>
#include <dlfcn.h>
#include "BacktraceUtils.h"

struct BacktraceState {
  void** current;
	void** end;
};

static _Unwind_Reason_Code unwindCallback(struct _Unwind_Context* context, void* arg)
{
	BacktraceState* state = static_cast<BacktraceState*>(arg);
	uintptr_t pc = _Unwind_GetIP(context);
	if(pc) {
		if(state->current == state->end) {
			return _URC_END_OF_STACK;
		} else {
			*state->current++ = reinterpret_cast<void*>(pc);
		}
	}
	return _URC_NO_REASON;
}

size_t captureBacktrace(void** buffer, size_t max)
{
	BacktraceState state = {buffer, buffer+max};
	_Unwind_Backtrace(unwindCallback, &state);
	return state.current - buffer;
}

void dumpBacktrace(std::ostream& os, void** buffer, size_t count)
{
	for(size_t idx=0; idx < count; ++idx) {
		const void* addr = buffer[idx];
		const char* symbol = "";

		Dl_info info;
		if(dladdr(addr, &info) && info.dli_sname) {
			symbol = info.dli_sname;
		}
		os << " #" << std::setw(2) << idx << ": " << addr << " " << symbol << "\n";
	}
}

void getBacktrace(std::ostringstream& oss, const size_t max)
{
	void* buffer[max];
	dumpBacktrace(oss, buffer, captureBacktrace(buffer, max));
}