From a7708b9e47299c6c48742e446d7705a75d5a3603 Mon Sep 17 00:00:00 2001
From: XeonSquared <redtailedairways@gmail.com>
Date: Wed, 20 Sep 2023 00:01:21 +1000
Subject: [PATCH] address RPC loop issues as described in
 https://github.com/ShadowKatStudios/OC-Minitel/pull/40 plus implement ACLs
 like the OpenOS version of the RPC library

---
 lib/rpc.lua | 50 ++++++++++++++++++++++++++++++++++----------------
 1 file changed, 34 insertions(+), 16 deletions(-)

diff --git a/lib/rpc.lua b/lib/rpc.lua
index 23dac4c..ab92fa4 100644
--- a/lib/rpc.lua
+++ b/lib/rpc.lua
@@ -5,19 +5,34 @@ local rpc = {}
 _G.rpcf = {}
 rpc.port = 111
 
-local function rpcexec(_, from, port, data)
- if port == rpc.port then
-  local rpcrq = serial.unserialize(data)
-  local rpcn, rpcid = table.remove(rpcrq,1), table.remove(rpcrq,1)
-  if rpcf[rpcn] then
-   local rt = {pcall(rpcf[rpcn],table.unpack(rpcrq))}
-   if rt[1] == true then
-    table.remove(rt,1)
-   end
-   minitel.send(from,port,serial.serialize({rpcid,table.unpack(rt)}))
-  else
-  end
+local function setacl(self, fname, host)
+ self[fname] = self[fname] or {}
+ self[fname][host] = true
+end
+rpc.allow = setmetatable({},{__call=setacl})
+rpc.deny = setmetatable({},{__call=setacl})
+
+local function isPermitted(host,fn)
+ if rpc.allow[fn] then
+  return rpc.allow[fn][host] or false
  end
+ if rpc.deny[fn] and rpc.deny[fn][host] then
+  return false
+ end
+ return true
+end
+
+local function rpcexec(_, from, port, data)
+ os.spawn(function()
+  if port == rpc.port then
+   local rpcrq = serial.unserialize(data) or {}
+   if rpcf[rpcrq[1]] and isPermitted(from,rpcrq[1]) then
+    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()
  local rt = {}
@@ -39,10 +54,13 @@ function rpc.call(hostname,fn,...) -- string string -- boolean -- Calls exported
   local _, from, port, data = event.pull(30, "net_msg", hostname, rpc.port)
   rt = serial.unserialize(tostring(data)) or {}
  until (type(rt) == "table" and rt[1] == rv) or computer.uptime() > st + 30
- if table.remove(rt,1) == rv then
-  return table.unpack(rt)
+ if rt[1] == rv then
+  if rt[2] then
+   return table.unpack(rt,3)
+  end
+  error(rt[3])
  end
- return false
+ error("timed out")
 end
 function rpc.proxy(hostname,filter) -- string string -- table -- Returns a component.proxy()-like table from the functions on *hostname* with names matching *filter*.
  filter=(filter or "").."(.+)"
@@ -69,7 +87,7 @@ function rpc.register(name,fn) -- string function -- -- Registers a function to
  if not rpcrunning then
   os.spawn(function()
    while true do
-    rpcexec(event.pull("net_msg"))
+    pcall(rpcexec,event.pull("net_msg"))
    end
   end,"rpc daemon")
  end