/*
 * ngIRCd -- The Next Generation IRC Daemon
 * Copyright (c)2001-2005 by Alexander Barton (alex@barton.de)
 *
 * This program 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 2 of the License, or
 * (at your option) any later version.
 * Please read the file COPYING, README and AUTHORS for more information.
 *
 * Main program -- main()
 */


#include "portab.h"

static char UNUSED id[] = "$Id: ngircd.c,v 1.94 2005/02/11 13:52:37 alex Exp $";

#include "imp.h"
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <pwd.h>
#include <grp.h>

#include "defines.h"
#include "resolve.h"
#include "conn.h"
#include "client.h"
#include "channel.h"
#include "conf.h"
#include "cvs-version.h"
#include "lists.h"
#include "log.h"
#include "parse.h"
#include "irc.h"

#ifdef RENDEZVOUS
#include "rendezvous.h"
#endif

#include "exp.h"
#include "ngircd.h"


LOCAL VOID Initialize_Signal_Handler PARAMS(( VOID ));
LOCAL VOID Signal_Handler PARAMS(( INT Signal ));

LOCAL VOID Show_Version PARAMS(( VOID ));
LOCAL VOID Show_Help PARAMS(( VOID ));

LOCAL VOID Pidfile_Create PARAMS(( LONG ));
LOCAL VOID Pidfile_Delete PARAMS(( VOID ));

LOCAL VOID Fill_Version PARAMS(( VOID ));

LOCAL VOID Setup_FDStreams PARAMS(( VOID ));


GLOBAL int
main( int argc, const char *argv[] )
{
	struct passwd *pwd;
	struct group *grp;
	BOOLEAN ok, configtest = FALSE;
	LONG pid, n;
	INT i;

	umask( 0077 );

	NGIRCd_SignalQuit = NGIRCd_SignalRestart = NGIRCd_SignalRehash = FALSE;
	NGIRCd_NoDaemon = NGIRCd_Passive = FALSE;
#ifdef DEBUG
	NGIRCd_Debug = FALSE;
#endif
#ifdef SNIFFER
	NGIRCd_Sniffer = FALSE;
#endif
	strlcpy( NGIRCd_ConfFile, SYSCONFDIR, sizeof( NGIRCd_ConfFile ));
	strlcat( NGIRCd_ConfFile, CONFIG_FILE, sizeof( NGIRCd_ConfFile ));

	Fill_Version( );

	/* Kommandozeile parsen */
	for( i = 1; i < argc; i++ )
	{
		ok = FALSE;
		if(( argv[i][0] == '-' ) && ( argv[i][1] == '-' ))
		{
			/* Lange Option */

			if( strcmp( argv[i], "--config" ) == 0 )
			{
				if( i + 1 < argc )
				{
					/* Ok, there's an parameter left */
					strlcpy( NGIRCd_ConfFile, argv[i + 1], sizeof( NGIRCd_ConfFile ));

					/* next parameter */
					i++; ok = TRUE;
				}
			}
			if( strcmp( argv[i], "--configtest" ) == 0 )
			{
				configtest = TRUE;
				ok = TRUE;
			}
#ifdef DEBUG
			if( strcmp( argv[i], "--debug" ) == 0 )
			{
				NGIRCd_Debug = TRUE;
				ok = TRUE;
			}
#endif
			if( strcmp( argv[i], "--help" ) == 0 )
			{
				Show_Version( );
				puts( "" ); Show_Help( ); puts( "" );
				exit( 1 );
			}
			if( strcmp( argv[i], "--nodaemon" ) == 0 )
			{
				NGIRCd_NoDaemon = TRUE;
				ok = TRUE;
			}
			if( strcmp( argv[i], "--passive" ) == 0 )
			{
				NGIRCd_Passive = TRUE;
				ok = TRUE;
			}
#ifdef SNIFFER
			if( strcmp( argv[i], "--sniffer" ) == 0 )
			{
				NGIRCd_Sniffer = TRUE;
				ok = TRUE;
			}
#endif
			if( strcmp( argv[i], "--version" ) == 0 )
			{
				Show_Version( );
				exit( 1 );
			}
		}
		else if(( argv[i][0] == '-' ) && ( argv[i][1] != '-' ))
		{
			/* Kurze Option */
			
			for( n = 1; n < (LONG)strlen( argv[i] ); n++ )
			{
				ok = FALSE;
#ifdef DEBUG
				if( argv[i][n] == 'd' )
				{
					NGIRCd_Debug = TRUE;
					ok = TRUE;
				}
#endif
				if( argv[i][n] == 'f' )
				{
					if(( ! argv[i][n + 1] ) && ( i + 1 < argc ))
					{
						/* Ok, next character is a blank */
						strlcpy( NGIRCd_ConfFile, argv[i + 1], sizeof( NGIRCd_ConfFile ));

						/* go to the following parameter */
						i++; n = (LONG)strlen( argv[i] );
						ok = TRUE;
					}
				}
				if( argv[i][n] == 'n' )
				{
					NGIRCd_NoDaemon = TRUE;
					ok = TRUE;
				}
				if( argv[i][n] == 'p' )
				{
					NGIRCd_Passive = TRUE;
					ok = TRUE;
				}
#ifdef SNIFFER
				if( argv[i][n] == 's' )
				{
					NGIRCd_Sniffer = TRUE;
					ok = TRUE;
				}
#endif
				if( argv[i][n] == 't' )
				{
					configtest = TRUE;
					ok = TRUE;
				}

				if( ! ok )
				{
					printf( "%s: invalid option \"-%c\"!\n", PACKAGE_NAME, argv[i][n] );
					printf( "Try \"%s --help\" for more information.\n", PACKAGE_NAME );
					exit( 1 );
				}
			}

		}
		if( ! ok )
		{
			printf( "%s: invalid option \"%s\"!\n", PACKAGE_NAME, argv[i] );
			printf( "Try \"%s --help\" for more information.\n", PACKAGE_NAME );
			exit( 1 );
		}
	}

	/* Debug-Level (fuer IRC-Befehl "VERSION") ermitteln */
	NGIRCd_DebugLevel[0] = '\0';
#ifdef DEBUG
	if( NGIRCd_Debug ) strcpy( NGIRCd_DebugLevel, "1" );
#endif
#ifdef SNIFFER
	if( NGIRCd_Sniffer )
	{
		NGIRCd_Debug = TRUE;
		strcpy( NGIRCd_DebugLevel, "2" );
	}
#endif

	/* Soll nur die Konfigurations ueberprueft und ausgegeben werden? */
	if( configtest )
	{
		Show_Version( ); puts( "" );
		exit( Conf_Test( ));
	}
	
	while( ! NGIRCd_SignalQuit )
	{
		/* Initialize global variables */
		NGIRCd_Start = time( NULL );
		(VOID)strftime( NGIRCd_StartStr, 64, "%a %b %d %Y at %H:%M:%S (%Z)", localtime( &NGIRCd_Start ));

		NGIRCd_SignalRehash = FALSE;
		NGIRCd_SignalRestart = FALSE;
		NGIRCd_SignalQuit = FALSE;

		/* Initialize modules, part I */
		Log_Init( );
		Conf_Init( );

		if( Conf_Chroot[0] )
		{
			/* Chroot */
			if( chdir( Conf_Chroot ) != 0 ) Log( LOG_ERR, "Can't chdir() in ChrootDir (%s): %s", Conf_Chroot, strerror( errno ));

			if( chroot( Conf_Chroot ) != 0 ) Log( LOG_ERR, "Can't change root directory to \"%s\": %s", Conf_Chroot, strerror( errno ));
			else Log( LOG_INFO, "Changed root and working directory to \"%s\".", Conf_Chroot );
		}

		if( Conf_GID != 0 )
		{
			/* Set new group ID */
			if( setgid( Conf_GID ) != 0 ) Log( LOG_ERR, "Can't change group ID to %u: %s", Conf_GID, strerror( errno ));
		}
		if( Conf_UID != 0 )
		{
			/* Set new user ID */
			if( setuid( Conf_UID ) != 0 ) Log( LOG_ERR, "Can't change user ID to %u: %s", Conf_UID, strerror( errno ));
		}

		/* Normally a child process is forked which isn't any longer
		 * connected to ther controlling terminal. Use "--nodaemon"
		 * to disable this "daemon mode" (useful for debugging). */
		if( ! NGIRCd_NoDaemon )
		{
			/* fork child process */
			pid = (LONG)fork( );
			if( pid > 0 )
			{
				/* "Old" process: exit. */
				exit( 0 );
			}
			if( pid < 0 )
			{
				/* Error!? */
				fprintf( stderr, "%s: Can't fork: %s!\nFatal error, exiting now ...\n", PACKAGE_NAME, strerror( errno ));
				exit( 1 );
			}

			/* New child process */
			(VOID)setsid( );
			chdir( "/" );

			/* Detach stdin, stdout and stderr */
			(VOID)Setup_FDStreams( );
		}

		/* Create PID file */
		pid = (LONG) getpid( );
		Pidfile_Create( pid );

		/* Show user, group, and PID of the running daemon */
		pwd = getpwuid( getuid( )); grp = getgrgid( getgid( ));
		Log( LOG_INFO, "Running as user %s(%ld), group %s(%ld), with PID %ld.", pwd ? pwd->pw_name : "unknown", (LONG)getuid( ), grp ? grp->gr_name : "unknown", (LONG)getgid( ), pid);

		/* Change working directory to home directory of the user
		 * we are running as (when not running chroot()'ed!) */
		if( Conf_UID != 0 && ! Conf_Chroot[0] )
		{
			struct passwd *pwd;

			pwd = getpwuid( Conf_UID );
			if( pwd != NULL )
			{
				if( chdir( pwd->pw_dir ) == 0 ) Log( LOG_DEBUG, "Changed working directory to \"%s\" ...", pwd->pw_dir );
				else Log( LOG_ERR, "Can't change working directory to \"%s\": %s", pwd->pw_dir, strerror( errno ));
			}
			else Log( LOG_ERR, "Can't get user informaton for UID %d!?", Conf_UID );
		}

		/* Initialize modules, part II: these functions are eventually
		 * called with already dropped privileges ... */
		Resolve_Init( );
		Lists_Init( );
		Channel_Init( );
		Client_Init( );
#ifdef RENDEZVOUS
		Rendezvous_Init( );
#endif
		Conn_Init( );

#ifdef DEBUG
		/* Redirect stderr handle to "error file" for debugging
		 * when not running in "no daemon" mode: */
		if( ! NGIRCd_NoDaemon ) Log_InitErrorfile( );
#endif

		/* Signal-Handler initialisieren */
		Initialize_Signal_Handler( );

		/* Protokoll- und Server-Identifikation erzeugen. Die vom ngIRCd
		 * beim PASS-Befehl verwendete Syntax sowie die erweiterten Flags
		 * sind in doc/Protocol.txt beschrieben. */
#ifdef IRCPLUS
		sprintf( NGIRCd_ProtoID, "%s%s %s|%s:%s", PROTOVER, PROTOIRCPLUS, PACKAGE_NAME, PACKAGE_VERSION, IRCPLUSFLAGS );
#ifdef ZLIB
		strcat( NGIRCd_ProtoID, "Z" );
#endif
		if( Conf_OperCanMode ) strcat( NGIRCd_ProtoID, "o" );
#else
		sprintf( NGIRCd_ProtoID, "%s%s %s|%s", PROTOVER, PROTOIRC, PACKAGE_NAME, PACKAGE_VERSION );
#endif
		strcat( NGIRCd_ProtoID, " P" );
#ifdef ZLIB
		strcat( NGIRCd_ProtoID, "Z" );
#endif
		Log( LOG_DEBUG, "Protocol and server ID is \"%s\".", NGIRCd_ProtoID );

		/* Vordefinierte Channels anlegen */
		Channel_InitPredefined( );

		/* Listen-Ports initialisieren */
		if( Conn_InitListeners( ) < 1 )
		{
			Log( LOG_ALERT, "Server isn't listening on a single port!" );
			Log( LOG_ALERT, "%s exiting due to fatal errors!", PACKAGE_NAME );
			Pidfile_Delete( );
			exit( 1 );
		}
		
		/* Hauptschleife */
		Conn_Handler( );

		/* Alles abmelden */
		Conn_Exit( );
#ifdef RENDEZVOUS
		Rendezvous_Exit( );
#endif
		Client_Exit( );
		Channel_Exit( );
		Lists_Exit( );
		Log_Exit( );

		Pidfile_Delete( );
	}

	return 0;
} /* main */


LOCAL VOID
Fill_Version( VOID )
{
	NGIRCd_VersionAddition[0] = '\0';

#ifdef SYSLOG
	strcpy( NGIRCd_VersionAddition, "SYSLOG" );
#endif
#ifdef ZLIB
	if( NGIRCd_VersionAddition[0] ) strcat( NGIRCd_VersionAddition, "+" );
	strcat( NGIRCd_VersionAddition, "ZLIB" );
#endif
#ifdef TCPWRAP
	if( NGIRCd_VersionAddition[0] ) strcat( NGIRCd_VersionAddition, "+" );
	strcat( NGIRCd_VersionAddition, "TCPWRAP" );
#endif
#ifdef RENDEZVOUS
	if( NGIRCd_VersionAddition[0] ) strcat( NGIRCd_VersionAddition, "+" );
	strcat( NGIRCd_VersionAddition, "RENDEZVOUS" );
#endif
#ifdef IDENTAUTH
	if( NGIRCd_VersionAddition[0] ) strcat( NGIRCd_VersionAddition, "+" );
	strcat( NGIRCd_VersionAddition, "IDENT" );
#endif
#ifdef DEBUG
	if( NGIRCd_VersionAddition[0] ) strcat( NGIRCd_VersionAddition, "+" );
	strcat( NGIRCd_VersionAddition, "DEBUG" );
#endif
#ifdef SNIFFER
	if( NGIRCd_VersionAddition[0] ) strcat( NGIRCd_VersionAddition, "+" );
	strcat( NGIRCd_VersionAddition, "SNIFFER" );
#endif
#ifdef STRICT_RFC
	if( NGIRCd_VersionAddition[0] ) strcat( NGIRCd_VersionAddition, "+" );
	strcat( NGIRCd_VersionAddition, "RFC" );
#endif
#ifdef IRCPLUS
	if( NGIRCd_VersionAddition[0] ) strcat( NGIRCd_VersionAddition, "+" );
	strcat( NGIRCd_VersionAddition, "IRCPLUS" );
#endif

	if( NGIRCd_VersionAddition[0] ) strlcat( NGIRCd_VersionAddition, "-", sizeof( NGIRCd_VersionAddition ));
	strlcat( NGIRCd_VersionAddition, TARGET_CPU, sizeof( NGIRCd_VersionAddition ));
	strlcat( NGIRCd_VersionAddition, "/", sizeof( NGIRCd_VersionAddition ));
	strlcat( NGIRCd_VersionAddition, TARGET_VENDOR, sizeof( NGIRCd_VersionAddition ));
	strlcat( NGIRCd_VersionAddition, "/", sizeof( NGIRCd_VersionAddition ));
	strlcat( NGIRCd_VersionAddition, TARGET_OS, sizeof( NGIRCd_VersionAddition ));

#ifdef CVSDATE
	snprintf( NGIRCd_Version, sizeof NGIRCd_Version,"%s %s(%s)-%s", PACKAGE_NAME, PACKAGE_VERSION, CVSDATE, NGIRCd_VersionAddition);
#else
	snprintf( NGIRCd_Version, sizeof NGIRCd_Version, "%s %s-%s", PACKAGE_NAME, PACKAGE_VERSION, NGIRCd_VersionAddition);
#endif
} /* Fill_Version */


GLOBAL VOID
NGIRCd_Rehash( VOID )
{
	CHAR old_name[CLIENT_ID_LEN];

	Log( LOG_NOTICE|LOG_snotice, "Re-reading configuration NOW!" );
	NGIRCd_SignalRehash = FALSE;

	/* Close down all listening sockets */
	Conn_ExitListeners( );

	/* Remember old server name */
	strcpy( old_name, Conf_ServerName );

	/* Re-read configuration ... */
	Conf_Rehash( );

	/* Recover old server name: it can't be changed during run-time */
	if( strcmp( old_name, Conf_ServerName ) != 0 )
	{
		strcpy( Conf_ServerName, old_name );
		Log( LOG_ERR, "Can't change \"ServerName\" on runtime! Ignored new name." );
	}

	/* Create new pre-defined channels */
	Channel_InitPredefined( );
	
	/* Start listening on sockets */
	Conn_InitListeners( );

	/* Sync configuration with established connections */
	Conn_SyncServerStruct( );

	Log( LOG_NOTICE|LOG_snotice, "Re-reading of configuration done." );
} /* NGIRCd_Rehash */


LOCAL VOID
Initialize_Signal_Handler( VOID )
{
	/* Signal-Handler initialisieren: einige Signale
	 * werden ignoriert, andere speziell behandelt. */

#ifdef HAVE_SIGACTION
	/* sigaction() ist vorhanden */

	struct sigaction saction;

	/* Signal-Struktur initialisieren */
	memset( &saction, 0, sizeof( saction ));
	saction.sa_handler = Signal_Handler;
#ifdef SA_RESTART
	saction.sa_flags |= SA_RESTART;
#endif
#ifdef SA_NOCLDWAIT
	saction.sa_flags |= SA_NOCLDWAIT;
#endif

	/* Signal-Handler einhaengen */
	sigaction( SIGINT, &saction, NULL );
	sigaction( SIGQUIT, &saction, NULL );
	sigaction( SIGTERM, &saction, NULL);
	sigaction( SIGHUP, &saction, NULL);
	sigaction( SIGCHLD, &saction, NULL);

	/* einige Signale ignorieren */
	saction.sa_handler = SIG_IGN;
	sigaction( SIGPIPE, &saction, NULL );
#else
	/* kein sigaction() vorhanden */

	/* Signal-Handler einhaengen */
	signal( SIGINT, Signal_Handler );
	signal( SIGQUIT, Signal_Handler );
	signal( SIGTERM, Signal_Handler );
	signal( SIGHUP, Signal_Handler );
	signal( SIGCHLD, Signal_Handler );

	/* einige Signale ignorieren */
	signal( SIGPIPE, SIG_IGN );
#endif
} /* Initialize_Signal_Handler */


LOCAL VOID
Signal_Handler( INT Signal )
{
	/* Signal-Handler. Dieser wird aufgerufen, wenn eines der Signale eintrifft,
	 * fuer das wir uns registriert haben (vgl. Initialize_Signal_Handler). Die
	 * Nummer des eingetroffenen Signals wird der Funktion uebergeben. */

	switch( Signal )
	{
		case SIGTERM:
		case SIGINT:
		case SIGQUIT:
			/* wir soll(t)en uns wohl beenden ... */
			NGIRCd_SignalQuit = TRUE;
			break;
		case SIGHUP:
			/* Konfiguration neu einlesen: */
			NGIRCd_SignalRehash = TRUE;
			break;
		case SIGCHLD:
			/* Child-Prozess wurde beendet. Zombies vermeiden: */
			while( waitpid( -1, NULL, WNOHANG ) > 0);
			break;
#ifdef DEBUG
		default:
			/* unbekanntes bzw. unbehandeltes Signal */
			Log( LOG_DEBUG, "Got signal %d! Ignored.", Signal );
#endif
	}
} /* Signal_Handler */


LOCAL VOID
Show_Version( VOID )
{
	puts( NGIRCd_Version );
	puts( "Copyright (c)2001-2005 by Alexander Barton (<alex@barton.de>)." );
	puts( "Homepage: <http://arthur.ath.cx/~alex/ngircd/>\n" );
	puts( "This is free software; see the source for copying conditions. There is NO" );
	puts( "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE." );
} /* Show_Version */


LOCAL VOID
Show_Help( VOID )
{
#ifdef DEBUG
	puts( "  -d, --debug        log extra debug messages" );
#endif
	puts( "  -f, --config <f>   use file <f> as configuration file" );
	puts( "  -n, --nodaemon     don't fork and don't detach from controlling terminal" );
	puts( "  -p, --passive      disable automatic connections to other servers" );
#ifdef SNIFFER
	puts( "  -s, --sniffer      enable network sniffer and display all IRC traffic" );
#endif
	puts( "  -t, --configtest   read, validate and display configuration; then exit" );
 	puts( "      --version      output version information and exit" );
	puts( "      --help         display this help and exit" );
} /* Show_Help */


LOCAL VOID
Pidfile_Delete( VOID )
{
	/* Pidfile configured? */
	if( ! Conf_PidFile[0] ) return;

#ifdef DEBUG
	Log( LOG_DEBUG, "Removing PID file (%s) ...", Conf_PidFile );
#endif

	if( unlink( Conf_PidFile ))
		Log( LOG_ERR, "Error unlinking PID file (%s): %s", Conf_PidFile, strerror( errno ));
} /* Pidfile_Delete */


LOCAL VOID
Pidfile_Create( LONG pid )
{
	FILE *pidf;

	/* Pidfile configured? */
	if( ! Conf_PidFile[0] ) return;

#ifdef DEBUG
	Log( LOG_DEBUG, "Creating PID file (%s) ...", Conf_PidFile );
#endif

	pidf = fopen( Conf_PidFile, "w" );

	if( ! pidf )
	{
		Log( LOG_ERR, "Error writing PID file (%s): %s", Conf_PidFile, strerror( errno ));
		return;
	}

	if( fprintf( pidf, "%ld\n", pid ) < 0 )
		Log( LOG_ERR, "Can't write PID file (%s): %s", Conf_PidFile, strerror( errno ));

	if( fclose(pidf) != 0 )
		Log( LOG_ERR, "Error closing PID file (%s): %s", Conf_PidFile, strerror( errno ));
} /* Pidfile_Create */


LOCAL VOID
Setup_FDStreams( VOID )
{
	INT fd;

	/* Test if we can open /dev/null for reading and writing. If not
	 * we are most probably chrooted already and the server has been
	 * restarted. So we simply don't try to redirect stdXXX ... */
	fd = open( "/dev/null", O_RDWR );
	if ( fd < 0 ) return;

	/* Close "old" stdin/out/err descriptors */
	close( 0 ); close( 1 ); close( 2 );

	/* Create new stdin(0), stdout(1) and stderr(2) descriptors */
	dup2( fd, 0 ); dup2( fd, 1 ); dup2( fd, 2 );

	/* Close newly opened file descriptor if not stdin/out/err */
	if( fd > 2 ) close( fd );
} /* Setup_FDStreams */


/* -eof- */