auth_checker

--[[
    Auth_checker by Théophile Bastian
    Vérifie une identité auprès du serveur d'authentification.

    Dépendances
    - sha256
    - slot_sig
--]]

------------- PARAMETERS --------------
ID_READER_SIDE = 'left'
MODEM_SIDE='top'

function onAllowed()
    redstone.setOutput('bottom',true)
    sleep(3)
    redstone.setOutput('bottom',false)
end
------------- END PARAMS --------------

os.loadAPI('/lib/sha256')
os.loadAPI('/lib/slot_sig')

local allowed = { users = {}, groups = {}}
local server = -1
local nextTimer = nil

function getHash()
    path = '/'..disk.getMountPath(ID_READER_SIDE)..'/key'

    handle = fs.open(path,'r')
    if(handle == nil) then
        return ""
    end

    key = handle.readAll()
    handle.close()

    hash = sha256.sha256(key)
    return hash
end

function onRednet(data)
    sender = data[1]

    mess=nil
    if(type(data[2]) == 'string') then
        mess = textutils.unserialize(mess)
    else
        mess = data[2]
    end

    if(mess.type == 'authreply') then
        if(mess.user == nil) then
            return
        end

        if(allowed.users[mess.user]) then
            onAllowed()
            return
        end

        for gid=1,#(mess.groups) do
            if(allowed.groups[mess.groups[gid]]) then
                onAllowed()
                return
            end
        end
    end
end

function requestAuth(hash)
    if(server == nil) then -- server still not found
        onAllowed() -- Allow login, to allow anyone in
    end

    mess = {}
    mess['reqtype'] = 'auth'
    mess['hash'] = hash
    rednet.send(server, textutils.serialize(mess))
end

function onDiskInserted(data)
    side=data[1]
    if side == ID_READER_SIDE then
        hash = getHash()
        disk.eject(ID_READER_SIDE)
        requestAuth(hash)
    end
end

function onTimer(data)
    if(data[1] == nextTimer and server == nil) then
        server = rednet.lookup('auth','server')
        if(server == nil) then
            nextTimer = os.startTimer(5)
        end
    end
end

function main()
    rednet.open(MODEM_SIDE)
    server = rednet.lookup('auth','server')

    if(server == nil) then
        nextTimer = os.startTimer(5)
    end

    slot_sig.connectSlot('disk', onDiskInserted)
    slot_sig.connectSlot('rednet_message', onRednet)
    slot_sig.connectSlot('timer',onTimer)

    slot_sig.run()
end
main()