XenStore protocol in OCaml

Layout of this project:

  core/        : protocol parser/printer, Lwt-based client
  core_test/   : unit tests for the protocol parser/printer
  unix/        : userspace 'transport' over sockets and xenbus mmap
  mirage/      : kernelspace 'transport' for Mirage
  xs/          : example userspace CLI

This code is all available under the standard Mirage license (ISC).

How to use the client

For Unix userspace, add the ocamlfind package 'xenstore.userspace' and create a 'Client':

#use "topfind";;
#require "lwt.syntax";;
#require "xenstore.userspace";;

open Lwt
module Client = Xenstore.Client.Make(Userspace)

To perform a single non-transactional read or wrote:

lwt my_domid = Client.(immediate (read_exn "domid"));;

To perform a transactional update:

Client.(transaction (
  let open M in
  write "a" "b" >>= fun () ->
  write "c" "d" >>= fun () ->
  return ()
))

To wait for a condition to be met:

Client.(wait (
  let open M in
  read "hotplug-status" >>= fun status ->
  read "hotplug-error" >>= fun error ->
  match status, error with
  | None, None -> return `Retry
  | _, Some error -> return (`Error error)
  | Some status, _ -> return (`Ok status)
))

Open issues

1. Xenstore.Client.Make is a nice name. Global 'Userspace' and 'Kernelspace' are a bit rude. Can these be made part of the Xenstore.* space somehow, even through they are optional?