Generalize RPC client code, add basic RPC functionality to client

asink/rpc_server.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"asink"
+	"net"
+	"net/http"
+	"net/rpc"
+)
+
+type ClientStopper int
+
+func (c *ClientStopper) StopClient(code *int, result *int) error {
+	asink.Exit(*code)
+	*result = 0
+	return nil
+}
+
+func StartRPC(sock string, tornDown chan int) {
+	defer func() { tornDown <- 0 }() //the main thread waits for this to ensure the socket is closed
+
+	clientstop := new(ClientStopper)
+	rpc.Register(clientstop)
+
+	rpc.HandleHTTP()
+	l, err := net.Listen("unix", sock)
+	if err != nil {
+		panic(err)
+	}
+	defer l.Close()
+
+	go http.Serve(l, nil)
+
+	asink.WaitOnExit()
+}