/*************************************************************************/
/*  crash_handler_x11.cpp                                                */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/*************************************************************************/
/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
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/* "Software"), to deal in the Software without restriction, including   */
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/* distribute, sublicense, and/or sell copies of the Software, and to    */
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/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
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/*************************************************************************/

#ifdef DEBUG_ENABLED
#define CRASH_HANDLER_ENABLED 1
#endif

#include "crash_handler_x11.h"
#include "main/main.h"
#include "os/os.h"
#include "project_settings.h"

#ifdef CRASH_HANDLER_ENABLED
#include <cxxabi.h>
#include <dlfcn.h>
#include <execinfo.h>
#include <signal.h>
#include <stdlib.h>

static void handle_crash(int sig) {
	if (OS::get_singleton() == NULL)
		return;

	void *bt_buffer[256];
	size_t size = backtrace(bt_buffer, 256);
	String _execpath = OS::get_singleton()->get_executable_path();
	String msg = GLOBAL_GET("debug/settings/crash_handler/message");

	// Dump the backtrace to stderr with a message to the user
	fprintf(stderr, "%s: Program crashed with signal %d\n", __FUNCTION__, sig);
	fprintf(stderr, "Dumping the backtrace. %ls\n", msg.c_str());
	char **strings = backtrace_symbols(bt_buffer, size);
	if (strings) {
		for (size_t i = 1; i < size; i++) {
			char fname[1024];
			Dl_info info;

			snprintf(fname, 1024, "%s", strings[i]);

			// Try to demangle the function name to provide a more readable one
			if (dladdr(bt_buffer[i], &info) && info.dli_sname) {
				if (info.dli_sname[0] == '_') {
					int status;
					char *demangled = abi::__cxa_demangle(info.dli_sname, NULL, 0, &status);

					if (status == 0 && demangled) {
						snprintf(fname, 1024, "%s", demangled);
					}

					if (demangled)
						free(demangled);
				}
			}

			List<String> args;

			char str[1024];
			snprintf(str, 1024, "%p", bt_buffer[i]);
			args.push_back(str);
			args.push_back("-e");
			args.push_back(_execpath);

			String output = "";

			// Try to get the file/line number using addr2line
			if (OS::get_singleton()) {
				int ret;
				Error err = OS::get_singleton()->execute(String("addr2line"), args, true, NULL, &output, &ret);
				if (err == OK) {
					output.erase(output.length() - 1, 1);
				}
			}

			fprintf(stderr, "[%ld] %s (%ls)\n", i, fname, output.c_str());
		}

		free(strings);
	}
	fprintf(stderr, "-- END OF BACKTRACE --\n");

	// Abort to pass the error to the OS
	abort();
}
#endif

CrashHandler::CrashHandler() {
	disabled = false;
}

CrashHandler::~CrashHandler() {
}

void CrashHandler::disable() {
	if (disabled)
		return;

#ifdef CRASH_HANDLER_ENABLED
	signal(SIGSEGV, NULL);
	signal(SIGFPE, NULL);
	signal(SIGILL, NULL);
#endif

	disabled = true;
}

void CrashHandler::initialize() {
#ifdef CRASH_HANDLER_ENABLED
	signal(SIGSEGV, handle_crash);
	signal(SIGFPE, handle_crash);
	signal(SIGILL, handle_crash);
#endif
}