/*************************************************************************/
/*  crash_handler_x11.cpp                                                */
/*************************************************************************/
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#include "crash_handler_linux.h"

#ifdef 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 <unistd.h>
#include <sys/wait.h>
#include <cstring>

#include "core/string.h"
#include "core/containers/vector.h"

#include "core/os/platform.h"
#include "core/error_macros.h"

static void handle_crash(int sig) {
	void *bt_buffer[256];
	size_t size = backtrace(bt_buffer, 256);
	String _execpath = Platform::get_singleton()->get_executable_path();

	// Dump the backtrace to stderr with a message to the user
	fprintf(stderr, "\n================================================================\n");
	fprintf(stderr, "%s: Program crashed with signal %d\n", __FUNCTION__, sig);

	fprintf(stderr, "Dumping the backtrace.\n");
	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, nullptr, nullptr, &status);

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

					if (demangled) {
						free(demangled);
					}
				}
			}

			Vector<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
			int ret;
			int err = Platform::get_singleton()->execute(String("addr2line"), args, true, nullptr, &output, &ret);

			if (err == 0) {
				output.erase(output.size() - 1, 1);
			}

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

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

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

CrashHandlerLinux::CrashHandlerLinux() : CrashHandler() {
}

CrashHandlerLinux::~CrashHandlerLinux() {
}

void CrashHandlerLinux::disable() {
	if (!enabled) {
		return;
	}

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

	enabled = false;
}

void CrashHandlerLinux::enable() {
	if (enabled) {
		return;
	}

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

	enabled = true;
}