/*****************************************************************************
The Dark Mod GPL Source Code

This file is part of the The Dark Mod Source Code, originally based
on the Doom 3 GPL Source Code as published in 2011.

The Dark Mod Source Code 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, either version 3 of the License,
or (at your option) any later version. For details, see LICENSE.TXT.

Project: The Dark Mod (http://www.thedarkmod.com/)

******************************************************************************/
#include "../../idlib/precompiled.h"
#include "posix_public.h"

#include <string.h>
#include <errno.h>

const int siglist[] = {
	SIGHUP,
	SIGQUIT,
	SIGILL,
	SIGTRAP,
	SIGIOT,
	SIGBUS,
	SIGFPE,
	SIGSEGV,
	SIGPIPE,
	SIGABRT,
	//	SIGTTIN,
	//	SIGTTOU,
	-1
	};

const char *signames[] = {
	"SIGHUP",
	"SIGQUIT",
	"SIGILL",
	"SIGTRAP",
	"SIGIOT",
	"SIGBUS",
	"SIGFPE",
	"SIGSEGV",
	"SIGPIPE",
	"SIGABRT",
	//	"SIGTTIN",
	//	"SIGTTOUT"
};

static char fatalError[ 1024 ];

/*
================
Posix_ClearSigs
================
*/
void Posix_ClearSigs( ) {
	struct sigaction action;
	int i;
	
	/* Set up the structure */
	action.sa_handler = SIG_DFL;
	sigemptyset( &action.sa_mask );
	action.sa_flags = 0;

	i = 0;
	while ( siglist[ i ] != -1 ) {
		if ( sigaction( siglist[ i ], &action, NULL ) != 0 ) {
			Sys_Printf( "Failed to reset %s handler: %s\n", signames[ i ], strerror( errno ) );
		}
		i++;
	}
}

/*
================
sig_handler
================
*/
static void sig_handler( int signum, siginfo_t *info, void *context ) {
	static bool double_fault = false;
	
	if ( double_fault ) {
		Sys_Printf( "double fault %s, bailing out\n", strsignal( signum ) );
		Posix_Exit( signum );
	}
	
	double_fault = true;
	
	// NOTE: see sigaction man page, could verbose the whole siginfo_t and print human readable si_code
	Sys_Printf( "signal caught: %s\nsi_code %d\n", strsignal( signum ), info->si_code );	
	
	if ( fatalError[ 0 ] ) {
		Sys_Printf( "Was in fatal error shutdown: %s\n", fatalError );
	}
	
	Sys_Printf( "Trying to exit gracefully..\n" );
	
	Posix_SetExit( signum );
	
	common->Quit();
}

/*
================
Posix_InitSigs
================
*/
void Posix_InitSigs( ) {
	struct sigaction action;
	int i;

	fatalError[0] = '\0';
	
	/* Set up the structure */
	action.sa_sigaction = sig_handler;
	sigemptyset( &action.sa_mask );
	action.sa_flags = SA_SIGINFO | SA_NODEFER;

	i = 0;
	while ( siglist[ i ] != -1 ) {
		if ( siglist[ i ] == SIGFPE ) {
			action.sa_sigaction = Sys_FPE_handler;
			if ( sigaction( siglist[ i ], &action, NULL ) != 0 ) {
				Sys_Printf( "Failed to set SIGFPE handler: %s\n", strerror( errno ) );
			}
			action.sa_sigaction = sig_handler;
		} else if ( sigaction( siglist[ i ], &action, NULL ) != 0 ) {
			Sys_Printf( "Failed to set %s handler: %s\n", signames[ i ], strerror( errno ) );
		}
		i++;
	}

	// if the process is backgrounded (running non interactively)
	// then SIGTTIN or SIGTOU could be emitted, if not caught, turns into a SIGSTP
	signal( SIGTTIN, SIG_IGN );
	signal( SIGTTOU, SIG_IGN );	
}

/*
==================
Sys_SetFatalError
==================
*/
void Sys_SetFatalError( const char *error ) {
	strncpy( fatalError, error, sizeof( fatalError ) );
}