Strengthening Password Server Security

rednet.open('top')
--This is a console

os.loadAPI('functions')
os.loadAPI('errors')

local function header()
	
	term.clear()
	term.setCursorPos(1,1)
	
	print('HimCo Industries\' Experimental OS')
	print()
	
end	

local function registerComputer()

	local msg=functions.ser({id=os.getComputerID(),action='registerComputer'})
	rednet.broadcast(msg)
	print('looking for valid router')
	local id=rednet.receive(5)
	if not id then
		print('Could not find valid router.')
		return false
	end
	local id,msg=functions.receiveMessage(5)
	if not id then
		print('No valid router found')
		return false
	end
	print(msg)
	textutils.tabulate(msg)
	local values=functions.unser(msg)
	
	if values['action']=='computerAdded' then
	
		print('saving router id #',values['id'],' as parent router')
		functions.saveToFile('parent_id',values['id'],'config')
		return true
		
	end

end

local function checkSession()
	
	if functions.loadFromFile('session')=='Guest' then
		return true
	end
	
	local msg=functions.ser({action='password_server',id=os.getComputerID(),value='session',username=functions.loadFromFile('session','config')})
	functions.sendMessage(parent_id,msg)
	
	local id,msg=functions.receiveMessage(3)
	
	if errors.noService(id,'error') then
		return 'error'
	end
	
	local values=functions.unser(msg)
	
	if values['user_id']==os.getComputerID() then
		functions.saveToFile('session',values['username'])
		return true
	else
		return values['value']
	end

end

local function login()
	header()
	
	write('Please give your username: ')
	local username=read()
	print()
	
	write('Please give your password: ')
	local password=read('*')
	
	local msg=functions.ser({action='password_server',id=os.getComputerID(),value='login',password=password, username=username})
	if functions.sendMessage(parent_id,msg) then
	
		local id,msg=functions.receiveMessage(5)
		
		if errors.noService(id) then
	
			print('Could not connect to server. Do you want to enter offline mode?')
			if functions.dichotomy('Go Offline','Quit') then
				functions.saveToFile('session','Guest')
			end
			
		end
			
		
		local values=functions.unser(msg)
		if values['session']~=os.getComputerID() then
		
			print('That profile is already open on computer #',values['session'],'. Please logout there, and try again.')
			sleep(2)
			os.reboot()
			
		elseif values['value'] and values['session']==os.getComputerID() then
		
			print('User ',username,' has been logged in.')
			functions.saveToFile('session',username)
			sleep(2)
			return true
			--os.reboot()
			
		else
			sleep(2)
			print('Username and password combination do not match')
			sleep(2)
			os.reboot()
			
		end	
	else
		print('Could not connect to server. Do you want to enter offline mode?')
		if functions.dichotomy('Go Offline','Quit') then
			functions.saveToFile('session','Guest')
		else
			os.reboot()
		end
	end
end

local function registerAccount()

	local password
	local username
	
	while true do
		
		header()
		write('Give a username: ')
		username=read()
		
		write('Give a password: ')
		password=read('*')
	
		write('Please confirm password: ')
		local tmp=read('*')
	
		if tmp==password then break end
		print('Passwords do not match, please try again')
		sleep(1.5)
	
	end

	local msg=functions.ser({action='password_server',id=os.getComputerID(),value='create',password=password,username=username})
	functions.sendMessage(parent_id,msg)

	local id,msg=functions.receiveMessage()

	local values=functions.unser(msg)
	
	if values['action']=='return' and values['value'] then
	
		print('Account created.')
		sleep(2)
		os.reboot()
	
	else
	
		print('Account already exists.')
		sleep(2)
		os.reboot()
		
	end
	
end
	

local function validate(parent_id)

	local choices={
		'Login',
		'Create Account',
		'Shutdown'
	}

	local choice=functions.multipleChoice(choices,1,2)
	if not choice then
		os.reboot()
	end
	
	if choice==1 then

		login()
	
	elseif choice==2 then
		
		registerAccount()
		
	elseif choice==3 then
	
		os.shutdown()
		
	end
end

functions.createFile('config')

if not functions.loadFromFile('parent_id','config') then

	registerComputer()
	
end

parent_id=functions.loadFromFile('parent_id')

local session=checkSession()

if not session then

	header()
	validate(parent_id)

elseif session=='error' then
	
	print('Could not connect to server. Do you want to enter offline mode?')
	if functions.dichotomy('Go Offline','Quit') then
		functions.saveToFile('session','Guest')
	else
		os.reboot()
	end
	
end
shell.setDir('files')
shell.run('menu')

os.loadAPI('functions')
rednet.open('top')
shell.run('clear')
local function header()
	functions.lineClear()
	functions.printCentered('This is the password server')
	functions.lineClear()
	print()
	functions.lineClear()
	print('Computer:  #',os.getComputerID())
	functions.lineClear()
	print('Parent Computer:  #',parent_id)
	functions.lineClear()
	print()
	functions.lineClear()
	print('===================================================')
	functions.lineClear()
	print()
end

local function getParentId()
	parent_id=functions.loadFromFile('parent_id','config')
	if not parent_id then
		while true do
			local parent_id=functions.numbersOnly('Please give the id of the parent router: ',3)
			local msg=functions.ser({action='registerSubServer',id=os.getComputerID(),value='password_server'})
			if functions.sendMessage(parent_id,msg) then
				functions.saveToFile('parent_id',parent_id,'config')
				break
			else
				print('The requested router could not be found. Please check its availability, or try another id.')
			end
			sleep(0.01)
		end
	end
	return parent_id
end

local function manager(msg)
	local values=functions.unser(msg)
	functions.lineClear()
	print('Received message from Computer #',values['id'])
	functions.lineClear()
	print('Value is ',values['value'])
	local verify=false
	-------------------------------------
	if values['value']=='create' then
	--[----------------------------------
		if not functions.loadFromFile(values['username'],'passwords') then
			functions.saveToFile(values['username'],values['password'],'passwords')
			functions.lineClear()
			print('Created account for ',values['username'])
			verify=true
		end
		
		local msg=functions.ser({action='return',id=values['id'],value=verify})
		functions.sendMessage(parent_id,msg)
	-------------------------------------]	
	elseif values['value']=='login' then
	--[-----------------------------------
		if not functions.loadFromFile(values['username'],'sessions') then
			if functions.loadFromFile(values['username'],'passwords')==values['password'] then
				functions.lineClear()
				print('Logging in ',values['username'])
				functions.saveToFile(values['username'],values['id'],'sessions')
				verify=true
			end
		elseif values['id']==functions.loadFromFile(values['username'],'sessions') then
			verify=true
		end
		local msg=functions.ser({action='return',id=values['id'],value=verify,session=functions.loadFromFile(values['username'],'sessions')})
		functions.sendMessage(parent_id,msg)
	-------------------------------------]
	elseif values['value']=='session' then
	--[-----------------------------------
		user_id=functions.loadFromFile(values['username'],'sessions')
		verify=user_id==values['id']
		local msg=functions.ser({action='return',id=values['id'],value=verify,session_id=user_id,username=values['username']})
		functions.sendMessage(parent_id,msg)
		functions.lineClear()
		print('Send Message to ',values['id'])
	--------------------------------------]
	elseif values['value']=='logout' then
	--[------------------------------------
		if functions.loadFromFile(values['username'],'sessions')==values['id'] then
			functions.lineClear()
			print('Logging out ',values['username'])
			functions.saveToFile(values['username'],nil,'sessions')
			verify=true
		end
		
		local msg=functions.ser({action='return',id=values['id'],value=verify})
		functions.sendMessage(parent_id,msg)
	end
end

parent_id=getParentId()
header()
functions.createFile('config')
functions.createFile('passwords')
functions.createFile('sessions')
functions.saveToFile('Guest',false,'sessions')
parent_id=getParentId()


while true do
	local id,msg=functions.receiveMessage()
	manager(msg)
	local x,y=term.getCursorPos()
	term.setCursorPos(1,1)
	header()
	term.setCursorPos(x,y)
end