cleanup RPC library, make it possible to detect the client hostname when running RPC requests

lib/rpc.lua

@@ -9,6 +9,8 @@ local function setacl(self, fname, host)
  self[fname] = self[fname] or {}
  self[fname][host] = true
 end
+-- function rpc.allow(fn, host) -- string string -- -- Enable the allow list for function *fname* and add *host* to it.
+-- function rpc.deny(fn, host) -- string string -- -- Enable the deny list for function *fname* and add *host* to it.
 rpc.allow = setmetatable({},{__call=setacl})
 rpc.deny = setmetatable({},{__call=setacl})
 
@@ -23,15 +25,15 @@ local function isPermitted(host,fn)
 end
 
 local function rpcexec(_, from, port, data)
+ if port ~= rpc.port then return false end
  os.spawn(function()
-  if port == rpc.port then
   local rpcrq = serial.unserialize(data) or {}
   if rpcf[rpcrq[1]] and isPermitted(from,rpcrq[1]) then
+   os.setenv("RPC_CLIENT",from)
    minitel.send(from,port,serial.serialize({rpcrq[2],pcall(rpcf[rpcrq[1]],table.unpack(rpcrq,3))}))
   elseif type(rpcrq[2]) == "string" then
    minitel.send(from,port,serial.serialize({rpcrq[2],false,"function unavailable"}))
  end
-  end
  end,"rpc worker for "..tostring(from))
 end
 function rpcf.list()
@@ -94,4 +96,10 @@ function rpc.register(name,fn) -- string function -- -- Registers a function to
  rpcf[name] = fn
 end
 
+function rpc.unregister(name) -- string -- -- Removes a function from the RPC function registry, clearing any ACL rules.
+ rpcf[name] = nil
+ rpc.allow[name] = nil
+ rpc.deny[name] = nil
+end
+
 return rpc