/*************************************************************************/
/*  crash_handler_osx.mm                                                 */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
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/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/*************************************************************************/

#include "crash_handler_osx.h"

#include "core/config/project_settings.h"
#include "core/os/os.h"
#include "main/main.h"

#include <string.h>
#include <unistd.h>

#if defined(DEBUG_ENABLED)
#define CRASH_HANDLER_ENABLED 1
#endif

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

#include <mach-o/dyld.h>
#include <mach-o/getsect.h>

static uint64_t load_address() {
	const struct segment_command_64 *cmd = getsegbyname("__TEXT");
	char full_path[1024];
	uint32_t size = sizeof(full_path);

	if (cmd && !_NSGetExecutablePath(full_path, &size)) {
		uint32_t dyld_count = _dyld_image_count();
		for (uint32_t i = 0; i < dyld_count; i++) {
			const char *image_name = _dyld_get_image_name(i);
			if (image_name && strncmp(image_name, full_path, 1024) == 0) {
				return cmd->vmaddr + _dyld_get_image_vmaddr_slide(i);
			}
		}
	}

	return 0;
}

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

	void *bt_buffer[256];
	size_t size = backtrace(bt_buffer, 256);
	String _execpath = OS::get_singleton()->get_executable_path();

	String msg;
	const ProjectSettings *proj_settings = ProjectSettings::get_singleton();
	if (proj_settings) {
		msg = proj_settings->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);

	if (OS::get_singleton()->get_main_loop())
		OS::get_singleton()->get_main_loop()->notification(MainLoop::NOTIFICATION_CRASH);

	fprintf(stderr, "Dumping the backtrace. %s\n", msg.utf8().get_data());
	char **strings = backtrace_symbols(bt_buffer, size);
	if (strings) {
		void *load_addr = (void *)load_address();

		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);
				}
			}

			String output = fname;

			// Try to get the file/line number using atos
			if (bt_buffer[i] > (void *)0x0 && OS::get_singleton()) {
				List<String> args;
				char str[1024];

				args.push_back("-o");
				args.push_back(_execpath);
				args.push_back("-arch");
				args.push_back("x86_64");
				args.push_back("-l");
				snprintf(str, 1024, "%p", load_addr);
				args.push_back(str);
				snprintf(str, 1024, "%p", bt_buffer[i]);
				args.push_back(str);

				int ret;
				String out = "";
				Error err = OS::get_singleton()->execute(String("atos"), args, &out, &ret);
				if (err == OK && out.substr(0, 2) != "0x") {
					out.erase(out.length() - 1, 1);
					output = out;
				}
			}

			fprintf(stderr, "[%zu] %s\n", i, output.utf8().get_data());
		}

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

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

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

CrashHandler::~CrashHandler() {
	disable();
}

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
}