/*
 *  Copyright (C) 2002-2010  The DOSBox Team
 *
 *  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.
 *
 *  This program 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 this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/* $Id: shell.cpp,v 1.100 2009-07-08 20:05:41 c2woody Exp $ */

#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include "dosbox.h"
#include "regs.h"
#include "control.h"
#include "shell.h"
#include "callback.h"
#include "support.h"


Bitu call_shellstop;
/* Larger scope so shell_del autoexec can use it to
 * remove things from the environment */
Program * first_shell = 0; 

static Bitu shellstop_handler(void) {
	return CBRET_STOP;
}

static void SHELL_ProgramStart(Program * * make) {
	*make = new DOS_Shell;
}

#define AUTOEXEC_SIZE 4096
static char autoexec_data[AUTOEXEC_SIZE] = { 0 };
static std::list<std::string> autoexec_strings;
typedef std::list<std::string>::iterator auto_it;

void VFILE_Remove(const char *name);

void AutoexecObject::Install(const std::string &in) {
	if(GCC_UNLIKELY(installed)) E_Exit("autoexec: allready created %s",buf.c_str());
	installed = true;
	buf = in;
	autoexec_strings.push_back(buf);
	this->CreateAutoexec();

	//autoexec.bat is normally created AUTOEXEC_Init.
	//But if we are allready running (first_shell)
	//we have to update the envirionment to display changes

	if(first_shell)	{
		//create a copy as the string will be modified
		std::string::size_type n = buf.size();
		char* buf2 = new char[n + 1];
		safe_strncpy(buf2, buf.c_str(), n + 1);
		if((strncasecmp(buf2,"set ",4) == 0) && (strlen(buf2) > 4)){
			char* after_set = buf2 + 4;//move to variable that is being set
			char* test = strpbrk(after_set,"=");
			if(!test) {first_shell->SetEnv(after_set,"");return;}
			*test++ = 0;
			//If the shell is running/exists update the environment
			first_shell->SetEnv(after_set,test);
		}
		delete [] buf2;
	}
}

void AutoexecObject::InstallBefore(const std::string &in) {
	if(GCC_UNLIKELY(installed)) E_Exit("autoexec: allready created %s",buf.c_str());
	installed = true;
	buf = in;
	autoexec_strings.push_front(buf);
	this->CreateAutoexec();
}

void AutoexecObject::CreateAutoexec(void) {
	/* Remove old autoexec.bat if the shell exists */
	if(first_shell)	VFILE_Remove("AUTOEXEC.BAT");

	//Create a new autoexec.bat
	autoexec_data[0] = 0;
	size_t auto_len;
	for(auto_it it=  autoexec_strings.begin(); it != autoexec_strings.end(); it++) {
		auto_len = strlen(autoexec_data);
		if ((auto_len+(*it).length()+3)>AUTOEXEC_SIZE) {
			E_Exit("SYSTEM:Autoexec.bat file overflow");
		}
		sprintf((autoexec_data+auto_len),"%s\r\n",(*it).c_str());
	}
	if(first_shell) VFILE_Register("AUTOEXEC.BAT",(Bit8u *)autoexec_data,(Bit32u)strlen(autoexec_data));
}

AutoexecObject::~AutoexecObject(){
	if(!installed) return;

	// Remove the line from the autoexecbuffer and update environment
	for(auto_it it = autoexec_strings.begin(); it != autoexec_strings.end(); ) {
		if((*it) == buf) {
			it = autoexec_strings.erase(it);
			std::string::size_type n = buf.size();
			char* buf2 = new char[n + 1];
			safe_strncpy(buf2, buf.c_str(), n + 1);
			// If it's a environment variable remove it from there as well
			if((strncasecmp(buf2,"set ",4) == 0) && (strlen(buf2) > 4)){
				char* after_set = buf2 + 4;//move to variable that is being set
				char* test = strpbrk(after_set,"=");
				if(!test) continue;
				*test = 0;
				//If the shell is running/exists update the environment
				if(first_shell) first_shell->SetEnv(after_set,"");
			}
			delete [] buf2;
		} else it++;
	}
	this->CreateAutoexec();
}

DOS_Shell::DOS_Shell():Program(){
	input_handle=STDIN;
	echo=true;
	exit=false;
	bf=0;
	call=false;
	completion_start = NULL;
}

Bitu DOS_Shell::GetRedirection(char *s, char **ifn, char **ofn,bool * append) {

	char * lr=s;
	char * lw=s;
	char ch;
	Bitu num=0;
	bool quote = false;
	char* t;

	while ( (ch=*lr++) ) {
		if(quote && ch != '"') { /* don't parse redirection within quotes. Not perfect yet. Escaped quotes will mess the count up */
			*lw++ = ch;
			continue;
		}

		switch (ch) {
		case '"':
			quote = !quote;
			break;
		case '>':
			*append=((*lr)=='>');
			if (*append) lr++;
			lr=ltrim(lr);
			if (*ofn) free(*ofn);
			*ofn=lr;
			while (*lr && *lr!=' ' && *lr!='<' && *lr!='|') lr++;
			//if it ends on a : => remove it.
			if((*ofn != lr) && (lr[-1] == ':')) lr[-1] = 0;
//			if(*lr && *(lr+1)) 
//				*lr++=0; 
//			else 
//				*lr=0;
			t = (char*)malloc(lr-*ofn+1);
			safe_strncpy(t,*ofn,lr-*ofn+1);
			*ofn=t;
			continue;
		case '<':
			if (*ifn) free(*ifn);
			lr=ltrim(lr);
			*ifn=lr;
			while (*lr && *lr!=' ' && *lr!='>' && *lr != '|') lr++;
			if((*ifn != lr) && (lr[-1] == ':')) lr[-1] = 0;
//			if(*lr && *(lr+1)) 
//				*lr++=0; 
//			else 
//				*lr=0;
			t = (char*)malloc(lr-*ifn+1);
			safe_strncpy(t,*ifn,lr-*ifn+1);
			*ifn=t;
			continue;
		case '|':
			ch=0;
			num++;
		}
		*lw++=ch;
	}
	*lw=0;
	return num;
}	

void DOS_Shell::ParseLine(char * line) {
	LOG(LOG_EXEC,LOG_ERROR)("Parsing command line: %s",line);
	/* Check for a leading @ */
 	if (line[0] == '@') line[0] = ' ';
	line = trim(line);

	/* Do redirection and pipe checks */
	
	char * in  = 0;
	char * out = 0;

	Bit16u dummy,dummy2;
	Bit32u bigdummy = 0;
	Bitu num = 0;		/* Number of commands in this line */
	bool append;
	bool normalstdin  = false;	/* wether stdin/out are open on start. */
	bool normalstdout = false;	/* Bug: Assumed is they are "con"      */
	
	num = GetRedirection(line,&in, &out,&append);
	if (num>1) LOG_MSG("SHELL:Multiple command on 1 line not supported");
	if (in || out) {
		normalstdin  = (psp->GetFileHandle(0) != 0xff); 
		normalstdout = (psp->GetFileHandle(1) != 0xff); 
	}
	if (in) {
		if(DOS_OpenFile(in,OPEN_READ,&dummy)) {	//Test if file exists
			DOS_CloseFile(dummy);
			LOG_MSG("SHELL:Redirect input from %s",in);
			if(normalstdin) DOS_CloseFile(0);	//Close stdin
			DOS_OpenFile(in,OPEN_READ,&dummy);	//Open new stdin
		}
	}
	if (out){
		LOG_MSG("SHELL:Redirect output to %s",out);
		if(normalstdout) DOS_CloseFile(1);
		if(!normalstdin && !in) DOS_OpenFile("con",OPEN_READWRITE,&dummy);
		bool status = true;
		/* Create if not exist. Open if exist. Both in read/write mode */
		if(append) {
			if( (status = DOS_OpenFile(out,OPEN_READWRITE,&dummy)) ) {
				 DOS_SeekFile(1,&bigdummy,DOS_SEEK_END);
			} else {
				status = DOS_CreateFile(out,DOS_ATTR_ARCHIVE,&dummy);	//Create if not exists.
			}
		} else {
			status = DOS_OpenFileExtended(out,OPEN_READWRITE,DOS_ATTR_ARCHIVE,0x12,&dummy,&dummy2);
		}
		
		if(!status && normalstdout) DOS_OpenFile("con",OPEN_READWRITE,&dummy); //Read only file, open con again
		if(!normalstdin && !in) DOS_CloseFile(0);
	}
	/* Run the actual command */
	DoCommand(line);
	/* Restore handles */
	if(in) {
		DOS_CloseFile(0);
		if(normalstdin) DOS_OpenFile("con",OPEN_READWRITE,&dummy);
		free(in);
	}
	if(out) {
		DOS_CloseFile(1);
		if(!normalstdin) DOS_OpenFile("con",OPEN_READWRITE,&dummy);
		if(normalstdout) DOS_OpenFile("con",OPEN_READWRITE,&dummy);
		if(!normalstdin) DOS_CloseFile(0);
		free(out);
	}
}



void DOS_Shell::RunInternal(void)
{
	char input_line[CMD_MAXLINE] = {0};
	while(bf && bf->ReadLine(input_line)) 
	{
		if (echo) {
				if (input_line[0] != '@') {
					ShowPrompt();
					WriteOut_NoParsing(input_line);
					WriteOut_NoParsing("\n");
				};
			};
		ParseLine(input_line);
	}
	return;
}

void DOS_Shell::Run(void) {
	char input_line[CMD_MAXLINE] = {0};
	std::string line;
	if (cmd->FindStringRemain("/C",line)) {
		strcpy(input_line,line.c_str());
		char* sep = strpbrk(input_line,"\r\n"); //GTA installer
		if (sep) *sep = 0;
		DOS_Shell temp;
		temp.echo = echo;
		temp.ParseLine(input_line);		//for *.exe *.com  |*.bat creates the bf needed by runinternal;
		temp.RunInternal();				// exits when no bf is found.
		return;
	}
	/* Start a normal shell and check for a first command init */
	WriteOut(MSG_Get("SHELL_STARTUP_BEGIN"),VERSION);
#if C_DEBUG
	WriteOut(MSG_Get("SHELL_STARTUP_DEBUG"));
#endif
	if (machine == MCH_CGA) WriteOut(MSG_Get("SHELL_STARTUP_CGA"));
	if (machine == MCH_HERC) WriteOut(MSG_Get("SHELL_STARTUP_HERC"));
	WriteOut(MSG_Get("SHELL_STARTUP_END"));

	if (cmd->FindString("/INIT",line,true)) {
		strcpy(input_line,line.c_str());
		line.erase();
		ParseLine(input_line);
	}
	do {
		if (bf){
			if(bf->ReadLine(input_line)) {
				if (echo) {
					if (input_line[0]!='@') {
						ShowPrompt();
						WriteOut_NoParsing(input_line);
						WriteOut_NoParsing("\n");
					};
				};
				ParseLine(input_line);
				if (echo) WriteOut("\n");
			}
		} else {
			if (echo) ShowPrompt();
			InputCommand(input_line);
			ParseLine(input_line);
			if (echo && !bf) WriteOut_NoParsing("\n");
		}
	} while (!exit);
}

void DOS_Shell::SyntaxError(void) {
	WriteOut(MSG_Get("SHELL_SYNTAXERROR"));
}

class AUTOEXEC:public Module_base {
private:
	AutoexecObject autoexec[17];
	AutoexecObject autoexec_echo;
public:
	AUTOEXEC(Section* configuration):Module_base(configuration) {
		/* Register a virtual AUOEXEC.BAT file */
		std::string line;
		Section_line * section=static_cast<Section_line *>(configuration);

		/* Check -securemode switch to disable mount/imgmount/boot after running autoexec.bat */
		bool secure = control->cmdline->FindExist("-securemode",true);

		/* add stuff from the configfile unless -noautexec or -securemode is specified. */
		char * extra = const_cast<char*>(section->data.c_str());
		if (extra && !secure && !control->cmdline->FindExist("-noautoexec",true)) {
			/* detect if "echo off" is the first line */
			bool echo_off  = !strncasecmp(extra,"echo off",8);
			if (!echo_off) echo_off = !strncasecmp(extra,"@echo off",9);

			/* if "echo off" add it to the front of autoexec.bat */
			if(echo_off) autoexec_echo.InstallBefore("@echo off");

			/* Install the stuff from the configfile */
			autoexec[0].Install(section->data);
		}

		/* Check to see for extra command line options to be added (before the command specified on commandline) */
		/* Maximum of extra commands: 10 */
		Bitu i = 1;
		while (control->cmdline->FindString("-c",line,true) && (i <= 11)) {
#if defined (WIN32) || defined (OS2)
			//replace single with double quotes so that mount commands can contain spaces
			for(Bitu temp = 0;temp < line.size();++temp) if(line[temp] == '\'') line[temp]='\"';
#endif //Linux users can simply use \" in their shell
			autoexec[i++].Install(line);
		}

		/* Check for the -exit switch which causes dosbox to when the command on the commandline has finished */
		bool addexit = control->cmdline->FindExist("-exit",true);

		/* Check for first command being a directory or file */
		char buffer[CROSS_LEN];
		char orig[CROSS_LEN];
		char cross_filesplit[2] = {CROSS_FILESPLIT , 0};
		/* Combining -securemode and no parameter leaves you with a lovely Z:\. */ 
		if ( !control->cmdline->FindCommand(1,line) ) { 
			if ( secure ) autoexec[12].Install("z:\\config.com -securemode");
		} else {
			struct stat test;
			strcpy(buffer,line.c_str());
			if (stat(buffer,&test)){
				getcwd(buffer,CROSS_LEN);
				strcat(buffer,cross_filesplit);
				strcat(buffer,line.c_str());
				if (stat(buffer,&test)) goto nomount;
			}
			if (test.st_mode & S_IFDIR) { 
				autoexec[12].Install(std::string("MOUNT C \"") + buffer + "\"");
				autoexec[13].Install("C:");
				if(secure) autoexec[14].Install("z:\\config.com -securemode");
			} else {
				char* name = strrchr(buffer,CROSS_FILESPLIT);
				if (!name) { //Only a filename 
					line = buffer;
					getcwd(buffer,CROSS_LEN);
					strcat(buffer,cross_filesplit);
					strcat(buffer,line.c_str());
					if(stat(buffer,&test)) goto nomount;
					name = strrchr(buffer,CROSS_FILESPLIT);
					if(!name) goto nomount;
				}
				*name++ = 0;
				if (access(buffer,F_OK)) goto nomount;
				autoexec[12].Install(std::string("MOUNT C \"") + buffer + "\"");
				autoexec[13].Install("C:");
				/* Save the non modified filename (so boot and imgmount can use it (long filenames, case sensivitive)*/
				strcpy(orig,name);
				upcase(name);
				if(strstr(name,".BAT") != 0) {
					if(secure) autoexec[14].Install("z:\\config.com -securemode");
					/* BATch files are called else exit will not work */
					autoexec[15].Install(std::string("CALL ") + name);
					if(addexit) autoexec[16].Install("exit");
				} else if((strstr(name,".IMG") != 0) || (strstr(name,".IMA") !=0 )) {
					//No secure mode here as boot is destructive and enabling securemode disables boot
					/* Boot image files */
					autoexec[15].Install(std::string("BOOT ") + orig);
				} else if((strstr(name,".ISO") != 0) || (strstr(name,".CUE") !=0 )) {
					if(secure) autoexec[14].Install("z:\\config.com -securemode");
					/* imgmount CD image files */
					autoexec[15].Install(std::string("IMGMOUNT D \"") + orig + std::string("\" -t iso"));
					//autoexec[16].Install("D:");
					/* Makes no sense to exit here */
				} else {
					if(secure) autoexec[14].Install("z:\\config.com -securemode");
					autoexec[15].Install(name);
					if(addexit) autoexec[16].Install("exit");
				}
			}
		}
nomount:
		VFILE_Register("AUTOEXEC.BAT",(Bit8u *)autoexec_data,(Bit32u)strlen(autoexec_data));
	}
};

static AUTOEXEC* test;

void AUTOEXEC_Init(Section * sec) {
	test = new AUTOEXEC(sec);
}

static char const * const path_string="PATH=Z:\\";
static char const * const comspec_string="COMSPEC=Z:\\COMMAND.COM";
static char const * const full_name="Z:\\COMMAND.COM";
static char const * const init_line="/INIT AUTOEXEC.BAT";

void SHELL_Init() {
	/* Add messages */
	MSG_Add("SHELL_ILLEGAL_PATH","Illegal Path.\n");
	MSG_Add("SHELL_CMD_HELP","If you want a list of all supported commands type \033[33;1mhelp /all\033[0m .\nA short list of the most often used commands:\n");
	MSG_Add("SHELL_CMD_ECHO_ON","ECHO is on.\n");
	MSG_Add("SHELL_CMD_ECHO_OFF","ECHO is off.\n");
	MSG_Add("SHELL_ILLEGAL_SWITCH","Illegal switch: %s.\n");
	MSG_Add("SHELL_MISSING_PARAMETER","Required parameter missing.\n");
	MSG_Add("SHELL_CMD_CHDIR_ERROR","Unable to change to: %s.\n");
	MSG_Add("SHELL_CMD_CHDIR_HINT","To change to different drive type \033[31m%c:\033[0m\n");
	MSG_Add("SHELL_CMD_CHDIR_HINT_2","directoryname is longer than 8 characters and/or contains spaces.\nTry \033[31mcd %s\033[0m\n");
	MSG_Add("SHELL_CMD_CHDIR_HINT_3","You are still on drive Z:, change to a mounted drive with \033[31mC:\033[0m.\n");
	MSG_Add("SHELL_CMD_MKDIR_ERROR","Unable to make: %s.\n");
	MSG_Add("SHELL_CMD_RMDIR_ERROR","Unable to remove: %s.\n");
	MSG_Add("SHELL_CMD_DEL_ERROR","Unable to delete: %s.\n");
	MSG_Add("SHELL_SYNTAXERROR","The syntax of the command is incorrect.\n");
	MSG_Add("SHELL_CMD_SET_NOT_SET","Environment variable %s not defined.\n");
	MSG_Add("SHELL_CMD_SET_OUT_OF_SPACE","Not enough environment space left.\n");
	MSG_Add("SHELL_CMD_IF_EXIST_MISSING_FILENAME","IF EXIST: Missing filename.\n");
	MSG_Add("SHELL_CMD_IF_ERRORLEVEL_MISSING_NUMBER","IF ERRORLEVEL: Missing number.\n");
	MSG_Add("SHELL_CMD_IF_ERRORLEVEL_INVALID_NUMBER","IF ERRORLEVEL: Invalid number.\n");
	MSG_Add("SHELL_CMD_GOTO_MISSING_LABEL","No label supplied to GOTO command.\n");
	MSG_Add("SHELL_CMD_GOTO_LABEL_NOT_FOUND","GOTO: Label %s not found.\n");
	MSG_Add("SHELL_CMD_FILE_NOT_FOUND","File %s not found.\n");
	MSG_Add("SHELL_CMD_FILE_EXISTS","File %s already exists.\n");
	MSG_Add("SHELL_CMD_DIR_INTRO","Directory of %s.\n");
	MSG_Add("SHELL_CMD_DIR_BYTES_USED","%5d File(s) %17s Bytes.\n");
	MSG_Add("SHELL_CMD_DIR_BYTES_FREE","%5d Dir(s)  %17s Bytes free.\n");
	MSG_Add("SHELL_EXECUTE_DRIVE_NOT_FOUND","Drive %c does not exist!\nYou must \033[31mmount\033[0m it first. Type \033[1;33mintro\033[0m or \033[1;33mintro mount\033[0m for more information.\n");
	MSG_Add("SHELL_EXECUTE_ILLEGAL_COMMAND","Illegal command: %s.\n");
	MSG_Add("SHELL_CMD_PAUSE","Press any key to continue.\n");
	MSG_Add("SHELL_CMD_PAUSE_HELP","Waits for 1 keystroke to continue.\n");
	MSG_Add("SHELL_CMD_COPY_FAILURE","Copy failure : %s.\n");
	MSG_Add("SHELL_CMD_COPY_SUCCESS","   %d File(s) copied.\n");
	MSG_Add("SHELL_CMD_SUBST_NO_REMOVE","Removing drive not supported. Doing nothing.\n");
	MSG_Add("SHELL_CMD_SUBST_FAILURE","SUBST failed. You either made an error in your commandline or the target drive is already used.\nIt's only possible to use SUBST on Local drives");

	MSG_Add("SHELL_STARTUP_BEGIN",
		"\033[44;1m\xC9\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD"
		"\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD"
		"\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xBB\n"
		"\xBA \033[32mWelcome to DOSBox v%-8s\033[37m                                        \xBA\n"
		"\xBA                                                                    \xBA\n"
//		"\xBA DOSBox runs real and protected mode games.                         \xBA\n"
		"\xBA For a short introduction for new users type: \033[33mINTRO\033[37m                 \xBA\n"
		"\xBA For supported shell commands type: \033[33mHELP\033[37m                            \xBA\n"
		"\xBA                                                                    \xBA\n"
		"\xBA To adjust the emulated CPU speed, use \033[31mctrl-F11\033[37m and \033[31mctrl-F12\033[37m.       \xBA\n"
		"\xBA To activate the keymapper \033[31mctrl-F1\033[37m.                                 \xBA\n"
		"\xBA For more information read the \033[36mREADME\033[37m file in the DOSBox directory. \xBA\n"
		"\xBA                                                                    \xBA\n"
	);
	MSG_Add("SHELL_STARTUP_CGA","\xBA DOSBox supports Composite CGA mode.                                \xBA\n"
	        "\xBA Use \033[31m(alt-)F11\033[37m to change the colours when in this mode.             \xBA\n"
	        "\xBA                                                                    \xBA\n"
	);
	MSG_Add("SHELL_STARTUP_HERC","\xBA Use \033[31mF11\033[37m to cycle through white, amber, and green monochrome color. \xBA\n"
	        "\xBA                                                                    \xBA\n"
	);
	MSG_Add("SHELL_STARTUP_DEBUG",
	        "\xBA Press \033[31malt-Pause\033[37m to enter the debugger or start the exe with \033[33mDEBUG\033[37m. \xBA\n"
	        "\xBA                                                                    \xBA\n"
	);
	MSG_Add("SHELL_STARTUP_END",
	        "\xBA \033[32mHAVE FUN!\033[37m                                                          \xBA\n"
	        "\xBA \033[32mThe DOSBox Team \033[33mhttp://www.dosbox.com\033[37m                              \xBA\n"
	        "\xC8\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD"
	        "\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD"
	        "\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xCD\xBC\033[0m\n"
	        //"\n" //Breaks the startup message if you type a mount and a drive change.
	);
	MSG_Add("SHELL_CMD_CHDIR_HELP","Displays/changes the current directory.\n");
	MSG_Add("SHELL_CMD_CHDIR_HELP_LONG","CHDIR [drive:][path]\n"
	        "CHDIR [..]\n"
	        "CD [drive:][path]\n"
	        "CD [..]\n\n"
	        "  ..   Specifies that you want to change to the parent directory.\n\n"
	        "Type CD drive: to display the current directory in the specified drive.\n"
	        "Type CD without parameters to display the current drive and directory.\n");
	MSG_Add("SHELL_CMD_CLS_HELP","Clear screen.\n");
	MSG_Add("SHELL_CMD_DIR_HELP","Directory View.\n");
	MSG_Add("SHELL_CMD_ECHO_HELP","Display messages and enable/disable command echoing.\n");
	MSG_Add("SHELL_CMD_EXIT_HELP","Exit from the shell.\n");
	MSG_Add("SHELL_CMD_HELP_HELP","Show help.\n");
	MSG_Add("SHELL_CMD_MKDIR_HELP","Make Directory.\n");
	MSG_Add("SHELL_CMD_MKDIR_HELP_LONG","MKDIR [drive:][path]\n"
	        "MD [drive:][path]\n");
	MSG_Add("SHELL_CMD_RMDIR_HELP","Remove Directory.\n");
	MSG_Add("SHELL_CMD_RMDIR_HELP_LONG","RMDIR [drive:][path]\n"
	        "RD [drive:][path]\n");
	MSG_Add("SHELL_CMD_SET_HELP","Change environment variables.\n");
	MSG_Add("SHELL_CMD_IF_HELP","Performs conditional processing in batch programs.\n");
	MSG_Add("SHELL_CMD_GOTO_HELP","Jump to a labeled line in a batch script.\n");
	MSG_Add("SHELL_CMD_SHIFT_HELP","Leftshift commandline parameters in a batch script.\n");
	MSG_Add("SHELL_CMD_TYPE_HELP","Display the contents of a text-file.\n");
	MSG_Add("SHELL_CMD_TYPE_HELP_LONG","TYPE [drive:][path][filename]\n");
	MSG_Add("SHELL_CMD_REM_HELP","Add comments in a batch file.\n");
	MSG_Add("SHELL_CMD_REM_HELP_LONG","REM [comment]\n");
	MSG_Add("SHELL_CMD_NO_WILD","This is a simple version of the command, no wildcards allowed!\n");
	MSG_Add("SHELL_CMD_RENAME_HELP","Renames one or more files.\n");
	MSG_Add("SHELL_CMD_RENAME_HELP_LONG","RENAME [drive:][path]filename1 filename2.\n"
	        "REN [drive:][path]filename1 filename2.\n\n"
	        "Note that you can not specify a new drive or path for your destination file.\n");
	MSG_Add("SHELL_CMD_DELETE_HELP","Removes one or more files.\n");
	MSG_Add("SHELL_CMD_COPY_HELP","Copy files.\n");
	MSG_Add("SHELL_CMD_CALL_HELP","Start a batch file from within another batch file.\n");
	MSG_Add("SHELL_CMD_SUBST_HELP","Assign an internal directory to a drive.\n");
	MSG_Add("SHELL_CMD_LOADHIGH_HELP","Loads a program into upper memory (requires xms=true,umb=true).\n");
	MSG_Add("SHELL_CMD_CHOICE_HELP","Waits for a keypress and sets ERRORLEVEL.\n");
	MSG_Add("SHELL_CMD_CHOICE_HELP_LONG","CHOICE [/C:choices] [/N] [/S] text\n"
	        "  /C[:]choices  -  Specifies allowable keys.  Default is: yn.\n"
	        "  /N  -  Do not display the choices at end of prompt.\n"
	        "  /S  -  Enables case-sensitive choices to be selected.\n"
	        "  text  -  The text to display as a prompt.\n");
	MSG_Add("SHELL_CMD_ATTRIB_HELP","Does nothing. Provided for compatibility.\n");
	MSG_Add("SHELL_CMD_PATH_HELP","Provided for compatibility.\n");
	MSG_Add("SHELL_CMD_VER_HELP","View and set the reported DOS version.\n");
	MSG_Add("SHELL_CMD_VER_VER","DOSBox version %s. Reported DOS version %d.%02d.\n");

	/* Regular startup */
	call_shellstop=CALLBACK_Allocate();
	/* Setup the startup CS:IP to kill the last running machine when exitted */
	RealPt newcsip=CALLBACK_RealPointer(call_shellstop);
	SegSet16(cs,RealSeg(newcsip));
	reg_ip=RealOff(newcsip);

	CALLBACK_Setup(call_shellstop,shellstop_handler,CB_IRET,"shell stop");
	PROGRAMS_MakeFile("COMMAND.COM",SHELL_ProgramStart);

	/* Now call up the shell for the first time */
	Bit16u psp_seg=DOS_FIRST_SHELL;
	Bit16u env_seg=DOS_FIRST_SHELL+19; //DOS_GetMemory(1+(4096/16))+1;
	Bit16u stack_seg=DOS_GetMemory(2048/16);
	SegSet16(ss,stack_seg);
	reg_sp=2046;

	/* Set up int 24 and psp (Telarium games) */
	real_writeb(psp_seg+16+1,0,0xea);		/* far jmp */
	real_writed(psp_seg+16+1,1,real_readd(0,0x24*4));
	real_writed(0,0x24*4,((Bit32u)psp_seg<<16) | ((16+1)<<4));

	/* Set up int 23 to "int 20" in the psp. Fixes what.exe */
	real_writed(0,0x23*4,((Bit32u)psp_seg<<16));

	/* Setup MCBs */
	DOS_MCB pspmcb((Bit16u)(psp_seg-1));
	pspmcb.SetPSPSeg(psp_seg);	// MCB of the command shell psp
	pspmcb.SetSize(0x10+2);
	pspmcb.SetType(0x4d);
	DOS_MCB envmcb((Bit16u)(env_seg-1));
	envmcb.SetPSPSeg(psp_seg);	// MCB of the command shell environment
	envmcb.SetSize(DOS_MEM_START-env_seg);
	envmcb.SetType(0x4d);
	
	/* Setup environment */
	PhysPt env_write=PhysMake(env_seg,0);
	MEM_BlockWrite(env_write,path_string,(Bitu)(strlen(path_string)+1));
	env_write += (PhysPt)(strlen(path_string)+1);
	MEM_BlockWrite(env_write,comspec_string,(Bitu)(strlen(comspec_string)+1));
	env_write += (PhysPt)(strlen(comspec_string)+1);
	mem_writeb(env_write++,0);
	mem_writew(env_write,1);
	env_write+=2;
	MEM_BlockWrite(env_write,full_name,(Bitu)(strlen(full_name)+1));

	DOS_PSP psp(psp_seg);
	psp.MakeNew(0);
	dos.psp(psp_seg);
   
	/* The start of the filetable in the psp must look like this:
	 * 01 01 01 00 02
	 * In order to achieve this: First open 2 files. Close the first and
	 * duplicate the second (so the entries get 01) */
	Bit16u dummy=0;
	DOS_OpenFile("CON",OPEN_READWRITE,&dummy);	/* STDIN  */
	DOS_OpenFile("CON",OPEN_READWRITE,&dummy);	/* STDOUT */
	DOS_CloseFile(0);							/* Close STDIN */
	DOS_ForceDuplicateEntry(1,0);				/* "new" STDIN */
	DOS_ForceDuplicateEntry(1,2);				/* STDERR */
	DOS_OpenFile("CON",OPEN_READWRITE,&dummy);	/* STDAUX */
	DOS_OpenFile("CON",OPEN_READWRITE,&dummy);	/* STDPRN */

	psp.SetParent(psp_seg);
	/* Set the environment */
	psp.SetEnvironment(env_seg);
	/* Set the command line for the shell start up */
	CommandTail tail;
	tail.count=(Bit8u)strlen(init_line);
	strcpy(tail.buffer,init_line);
	MEM_BlockWrite(PhysMake(psp_seg,128),&tail,128);
	
	/* Setup internal DOS Variables */
	dos.dta(RealMake(psp_seg,0x80));
	dos.psp(psp_seg);

	
	SHELL_ProgramStart(&first_shell);
	first_shell->Run();
	delete first_shell;
	first_shell = 0;//Make clear that it shouldn't be used anymore
}