/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file crashlog_osx.cpp OS X crash log handler */

#include "../../stdafx.h"
#include "../../crashlog.h"
#include "../../string_func.h"
#include "../../gamelog.h"
#include "macos.h"

#include <errno.h>
#include <signal.h>
#include <mach-o/arch.h>
#include <dlfcn.h>
#include <cxxabi.h>


/* Macro testing a stack address for valid alignment. */
#if defined(__i386__)
#define IS_ALIGNED(addr) (((uintptr_t)(addr) & 0xf) == 8)
#else
#define IS_ALIGNED(addr) (((uintptr_t)(addr) & 0xf) == 0)
#endif

/* printf format specification for 32/64-bit addresses. */
#if __LP64__
#define PRINTF_PTR "0x%016lx"
#else
#define PRINTF_PTR "0x%08lx"
#endif

#define MAX_STACK_FRAMES 64

/**
 * OSX implementation for the crash logger.
 */
class CrashLogOSX : public CrashLog {
	/** Signal that has been thrown. */
	int signum;

	char filename_save[MAX_PATH];  ///< Path of crash.sav
	char filename_log[MAX_PATH];   ///< Path of crash.log

	/* virtual */ char *LogOSVersion(char *buffer, const char *last) const
	{
		int ver_maj, ver_min, ver_bug;
		GetMacOSVersion(&ver_maj, &ver_min, &ver_bug);

		const NXArchInfo *arch = NXGetLocalArchInfo();

		return buffer + seprintf(buffer, last,
				"Operating system:\n"
				" Name:    Mac OS X\n"
				" Release: %d.%d.%d\n"
				" Machine: %s\n"
				" Min Ver: %d\n\n",
				ver_maj, ver_min, ver_bug,
				arch != NULL ? arch->description : "unknown",
				MAC_OS_X_VERSION_MIN_REQUIRED
		);
	}

	/* virtual */ char *LogError(char *buffer, const char *last, const char *message) const
	{
		return buffer + seprintf(buffer, last,
				"Crash reason:\n"
				" Signal:  %s (%d)\n"
				" Message: %s\n\n",
				strsignal(this->signum),
				this->signum,
				message == NULL ? "<none>" : message
		);
	}

	/* virtual */ char *LogStacktrace(char *buffer, const char *last) const
	{
		/* As backtrace() is only implemented in 10.5 or later,
		 * we're rolling our own here. Mostly based on
		 * http://stackoverflow.com/questions/289820/getting-the-current-stack-trace-on-mac-os-x
		 * and some details looked up in the Darwin sources. */
		buffer += seprintf(buffer, last, "\nStacktrace:\n");

		void **frame;
#if defined(__ppc__) || defined(__ppc64__)
		/* Apple says __builtin_frame_address can be broken on PPC. */
		__asm__ volatile("mr %0, r1" : "=r" (frame));
#else
		frame = (void **)__builtin_frame_address(0);
#endif

		for (int i = 0; frame != NULL && i < MAX_STACK_FRAMES; i++) {
			/* Get IP for current stack frame. */
#if defined(__ppc__) || defined(__ppc64__)
			void *ip = frame[2];
#else
			void *ip = frame[1];
#endif
			if (ip == NULL) break;

			/* Print running index. */
			buffer += seprintf(buffer, last, " [%02d]", i);

			Dl_info dli;
			bool dl_valid = dladdr(ip, &dli) != 0;

			const char *fname = "???";
			if (dl_valid && dli.dli_fname) {
				/* Valid image name? Extract filename from the complete path. */
				const char *s = strrchr(dli.dli_fname, '/');
				if (s != NULL) {
					fname = s + 1;
				} else {
					fname = dli.dli_fname;
				}
			}
			/* Print image name and IP. */
			buffer += seprintf(buffer, last, " %-20s " PRINTF_PTR, fname, (uintptr_t)ip);

			/* Print function offset if information is available. */
			if (dl_valid && dli.dli_sname != NULL && dli.dli_saddr != NULL) {
				/* Try to demangle a possible C++ symbol. */
				int status = -1;
				char *func_name = abi::__cxa_demangle(dli.dli_sname, NULL, 0, &status);

				ptrdiff_t offset = (intptr_t)ip - (intptr_t)dli.dli_saddr;
				buffer += seprintf(buffer, last, " (%s + %d)", func_name != NULL ? func_name : dli.dli_sname, offset);

				free(func_name);
			}
			buffer += seprintf(buffer, last, "\n");

			/* Get address of next stack frame. */
			void **next = (void **)frame[0];
			/* Frame address not increasing or not aligned? Broken stack, exit! */
			if (next <= frame || !IS_ALIGNED(next)) break;
			frame = next;
		}

		return buffer + seprintf(buffer, last, "\n");
	}

public:
	/**
	 * A crash log is always generated by signal.
	 * @param signum the signal that was caused by the crash.
	 */
	CrashLogOSX(int signum) : signum(signum)
	{
		filename_log[0] = '\0';
		filename_save[0] = '\0';
	}

	/** Generate the crash log. */
	bool MakeCrashLog()
	{
		char buffer[65536];
		bool ret = true;

		printf("Crash encountered, generating crash log...\n");
		this->FillCrashLog(buffer, lastof(buffer));
		printf("%s\n", buffer);
		printf("Crash log generated.\n\n");

		printf("Writing crash log to disk...\n");
		if (!this->WriteCrashLog(buffer, filename_log, lastof(filename_log))) {
			filename_log[0] = '\0';
			ret = false;
		}

		printf("Writing crash savegame...\n");
		if (!this->WriteSavegame(filename_save, lastof(filename_save))) {
			filename_save[0] = '\0';
			ret = false;
		}

		return ret;
	}

	/** Show a dialog with the crash information. */
	void DisplayCrashDialog() const
	{
		static const char crash_title[] =
			"A serious fault condition occured in the game. The game will shut down.";
		static const char crash_info[] =
			"Please send the generated crash information and the last (auto)save to the developers. "
			"This will greatly help debugging. The correct place to do this is http://bugs.openttd.org.\n\n"
			"Generated file(s):\n%s\n%s";

		char message[1024];
		seprintf(message, lastof(message), crash_info, this->filename_log, this->filename_save);

		ShowMacDialog(crash_title, message, "Quit");
	}
};

/** The signals we want our crash handler to handle. */
static const int _signals_to_handle[] = { SIGSEGV, SIGABRT, SIGFPE, SIGBUS, SIGILL, SIGSYS };

/**
 * Entry point for the crash handler.
 * @note Not static so it shows up in the backtrace.
 * @param signum the signal that caused us to crash.
 */
void CDECL HandleCrash(int signum)
{
	/* Disable all handling of signals by us, so we don't go into infinite loops. */
	for (const int *i = _signals_to_handle; i != endof(_signals_to_handle); i++) {
		signal(*i, SIG_DFL);
	}

	if (GamelogTestEmergency()) {
		ShowMacDialog("A serious fault condition occured in the game. The game will shut down.",
				"As you loaded an emergency savegame no crash information will be generated.\n",
				"Quit");
		abort();
	}

	CrashLogOSX log(signum);
	log.MakeCrashLog();
	log.DisplayCrashDialog();

	CrashLog::AfterCrashLogCleanup();
	abort();
}

/* static */ void CrashLog::InitialiseCrashLog()
{
	for (const int *i = _signals_to_handle; i != endof(_signals_to_handle); i++) {
		signal(*i, HandleCrash);
	}
}