Add telnet (kinda)

halyde/apps/telnet.lua

@@ -0,0 +1,60 @@
+-- Despite the name it's not telnet
+local component = require("component")
+if not component.isAvailable("internet") then
+  terminal.write("telnet: this program requires an internet card to run\n")
+  return
+end
+
+local internet = component.internet
+if not internet.isTcpEnabled() then
+  terminal.write("telnet: TCP disabled\n")
+  return
+end
+
+local arg = {...}
+local host = arg[1]
+local port = tonumber(arg[2])
+
+local sock = internet.connect(host, port)
+
+local connected = false
+local err
+for _ = 1, 5 do
+  local ok
+  ok, err = sock.finishConnect()
+  if ok then
+    connected = true
+    break
+  end
+  coroutine.yield()
+end
+if not connected then
+  print("telnet: " .. err)
+  return
+end
+
+print(("connected to %s:%d"):format(host, port))
+
+while true do
+  local fromSocket = sock.read(math.maxinteger or math.huge)
+  if fromSocket == nil then
+    print("telnet: connection closed")
+    sock.close()
+    return
+  end
+  terminal.write(fromSocket)
+  terminal.flush()
+  local fromTerminal = terminal.read()
+  if fromTerminal == "" then
+    sock.close()
+    return
+  end
+  while fromTerminal ~= "" do
+    local nbytes, err = sock.write(fromTerminal .. "\r\n")
+    if err then
+      print("telnet: " .. err)
+      return
+    end
+    fromTerminal = fromTerminal:sub(nbytes + 1)
+  end
+end