CCraft - chroot

--[[chroot]]--

local args = {...}
local cmd = args[1]

if chroot then
    if #args == 0 then
        error("chroot already ran",2)
    end
else
    local fs,Path,Protected = fs

    local oldfs = {}
    for k,v in pairs(fs) do
        oldfs[k] = v
    end

    local chroot = {}
    _G.chroot = setmetatable({},{
        __index = function(s,k)
            local v = chroot[k]
            if k == "Protected" then
                return not not Protected
            elseif type(v) == "function" then
                return function(...)
                    return v(...)
                end
            end return v
        end;
    })

    local function up(path,err)
        path = path:gsub("^/","")
        path = path:gsub("/$","")
        if not path:find("/") then
            if err then
                error("Invalid Path",0)
            end return path
        end return path:match("^(.*)/.-$")
    end
    local function cleanPath(path,err)
        local parts = {}
        for v in path:gmatch("[^/]+") do
            table.insert(parts,v)
        end
        local start = ""
        for i=1,#parts do
            local p = parts[i]
            if p == ".." then
                start = up(start,err)
            else
                start = start.."/"..p
            end
        end return (start:gsub("^/",""))
    end

    local function checkPath(path,err)
        local level = 0
        for v in path:gmatch("[^/]") do
            if v == ".." then
                level = level - 1
            else
                level = level + 1
            end
        end
        if err and level < 0 then
            error("Invalid Path",4)
        end return path
    end

    shareds = {"rom","chroot"}
    local function shared(p)
        for k,v in pairs(shareds) do
            if p:match("^(%w+)/") == v or p == v then
                return true
            end
        end
    end

    local function makePath(path,err)
        if not Path then return path end
        if type(path) ~= "string" then return path end
        path = cleanPath(path,err)
        if shared(path) then
            return path
        end return Path.."/"..checkPath(path,err):gsub("^/","")
    end

    local newfs = {
        getName = oldfs.getName;
        combine =  oldfs.combine;
        move = function(a,b)
            return oldfs.move(makePath(a,true),makePath(b,true))
        end;
        copy = function(a,b)
            return oldfs.copy(makePath(a,true),makePath(b,true))
        end;
        complete = function(a,b,...)
            local s,e = pcall(makePath,b,true)
            if not s then return {} end
            return oldfs.complete(a,makePath(b))
        end;
        list = function(p)
            if not Path then return oldfs.list(p) end
            p = makePath(cleanPath(p),true)
            local res = oldfs.list(p)
            if shared(p) then return res end
            for k,v in pairs(res) do
                if v == "rom" then
                    return res
                end
            end
            if p:sub(1,#Path) == Path then
                table.insert(res,1,"rom")
            end return res
        end;
        exists = function(p)
            local s,e = pcall(makePath,b,true)
            if not s then return false end
            return oldfs.exists(makePath(p))
        end;
        isDir = function(p)
            local s,e = pcall(makePath,b,true)
            if not s then return false end
            return oldfs.isDir(makePath(p))
        end;
    }

    for k,v in pairs(oldfs) do
        if newfs[k] then
            fs[k] = newfs[k]
        else
            fs[k] = function(p,...)
                return v(makePath(p,true),...)
            end;
        end
    end

    function chroot:exit()
        if Protected then
            error("No permission to chroot",0)
        end Path = nil
    end

    function chroot:activate(folder,prot)
        if Protected then
            error("No permission to chroot",0)
        elseif not fs.isDir(folder) then
            error("Folder Expected",2)
        end self:exit() Protected = prot
        Path = cleanPath(folder:gsub("/$",""))
    end
end

local usage = [[
Usage:
    chroot exit
        Stop the current chroot
    chroot <folder>
        Set the current chroot
]]

local function syntax()
    local col = term.getTextColor()
    if term.isColor() then
        term.setTextColor(colors.red)
    end print(usage)
    term.setTextColor(col)
end

if type(cmd) == "string" then
    if chroot.Protected then
        error("No permission to chroot",0)
    elseif #args == 1 and cmd:lower() == "exit" then
        chroot:exit()
    elseif #args > 0 and cmd ~= "help" and cmd ~= "?" then
        local prot = args[2]=="true"
        if not fs.isDir(cmd) then
            error("Folder Expected",0)
        end chroot:activate(cmd,prot)
        prot = prot and " (protected)
        print("Chroot set to ",cmd,prot)
    else
        syntax()
    end
end