Sandbox Program

local args={...}
local sandboxed = args[1]
local privTable={}

--Debug:
--print(sandboxed)

--Check if loaded...
if fs.setReadOnly then error("Already loaded!!!",2) end

privTable["aliases"]=shell.aliases()

--Backup FS declaration...
local oFs={}
for k, v in pairs(fs) do
    oFs[k]=v
end

--Backup others declaration...
local oldDfile=dofile
local oldLfile=loadfile
local err = error



--Security declarations...
local oldsenv=setfenv

local rT={[1] = sandboxed}

local function check(filename)
    for k,v in pairs(rT) do
        if v==filename then return true end
    end
    return false
end

local function isAllowed()
    --stub function, change it to fit your OS'es needs.
    return false
end

local function errorout()
    err("Insufficient permissions.",3)
end

--Start with the declaring...

function fs.open(f,v)
    f=sandboxed..f or sandboxed
    if isAllowed() then return oFs.open(f,v) end
    if v ~= ("r" or "rb" or nil) then
        if check(f) then
            errorout()
        end
    end
    return oFs.open(f,v)
end

function fs.exists(f)
    f=sandboxed..f or sandboxed
    return oFs.exists(f)
end

function fs.isDir(f)
    f=sandboxed..f or sandboxed
    return oFs.isDir(f)
end

function fs.delete(f)
    f=sandboxed..f or sandboxed
    if isAllowed() then return oFs.delete(f) end
    if check(f) then
        errorout()
    end
    return oFs.delete(f)
end

function fs.copy(f,v)
    f=sandboxed..f or sandboxed
    v=sandboxed..v or sandboxed
    if isAllowed() then return oFs.copy(f,v) end
    if check(f) then
        errorout()
    end
    return oFs.copy(f,v)
end

function fs.move(f,v)
    f=sandboxed..f or sandboxed
    v=sandboxed..v or sandboxed
    if isAllowed() then return oFs.move(f,v) end
    if check(f) then
        errorout()
    end
    return oFs.move(f,v)
end

function fs.isReadOnly(f)
    f=sandboxed..f or sandboxed
    if check(f) then
        return true
    end
    return oFs.isReadOnly(f)
end

function fs.setReadOnly(file, bool)
    file=sandboxed..file or sandboxed
    if not isAllowed() then errorout() return nil end
    if not type(bool) == "boolean" then error("Boolean expected, got "..type(bool)..".") end
    if bool then
        if not check(file) then
            table.insert(rT, file)
        end
        return true
    else
        for k,v in pairs(rT) do
            if v == file then
                table.remove(rT, k)
                local derp = true
            end
        end
        if derp then return true end
        return false
    end
end

function fs.list(dir)
    if type(dir)=="string" then
        if string.sub(dir,#dir,#dir) == "/" then dir = string.sub(dir,1,#dir-1) end
    end
    dir=dir..sandboxed or sandboxed
    return oFs.list(dir)
end

function setfenv(...)
    return oldsenv(...)
end


function restore()
    if not isAllowed() then errorout() end
    fs={}
    for k,v in pairs(oFs) do
        fs[k]=v
    end
    dofile=oldDfile
    loadfile=oldLfile
    setfenv=oldsenv
    restore=nil
    for k,v in pairs(privTable.aliases) do
        shell.setAlias(k,v)
    end
end

--Clear aliases...
for k,v in pairs(privTable.aliases) do
    shell.clearAlias(k,v)
end