Add Net.listening_addr.

lib_eio/mock/eio_mock.mli

@@ -132,8 +132,11 @@ module Net : sig
 
   val on_getnameinfo : t -> (string * string) Handler.actions -> unit
 
-  val listening_socket : string -> listening_socket
-  (** [listening_socket label] can be configured to provide mock connections. *)
+  val listening_socket :
+    ?listening_addr:Eio.Net.Sockaddr.stream -> string -> listening_socket
+  (** [listening_socket label] can be configured to provide mock connections.
+
+      If [listening_addr] is not provided, a dummy value will be reported. *)
 
   val on_accept :
     listening_socket ->

lib_eio/mock/net.ml

@@ -97,14 +97,16 @@ type listening_socket = listening_socket_ty r
 module Listening_socket = struct
   type t = {
     label : string;
+    listening_addr : Eio.Net.Sockaddr.stream;
     on_accept : (Flow.t * Eio.Net.Sockaddr.stream) Handler.t;
   }
 
   type tag = [`Generic]
 
-  let make label =
+  let make ?(listening_addr = `Tcp (Eio.Net.Ipaddr.V4.any, 0)) label =
     {
       label;
+      listening_addr;
       on_accept = Handler.make (`Raise (Failure "Mock accept handler not configured"))
     }
 
@@ -119,6 +121,8 @@ module Listening_socket = struct
   let close t =
     traceln "%s: closed" t.label
 
+  let listening_addr { listening_addr; _ } = listening_addr
+
   type (_, _, _) Eio.Resource.pi += Type : ('t, 't -> t, listening_socket_ty) Eio.Resource.pi
   let raw (Eio.Resource.T (t, ops)) = Eio.Resource.get ops Type t
 end
@@ -129,8 +133,8 @@ let listening_socket_handler =
     H (Listening_socket.Type, Fun.id);
   ]
 
-let listening_socket label : listening_socket =
-  Eio.Resource.T (Listening_socket.make label, listening_socket_handler)
+let listening_socket ?listening_addr label : listening_socket =
+  Eio.Resource.T (Listening_socket.make ?listening_addr label, listening_socket_handler)
 
 let on_accept l actions =
   let r = Listening_socket.raw l in

lib_eio/net.ml

@@ -218,6 +218,7 @@ module Pi = struct
 
     val accept : t -> sw:Switch.t -> tag stream_socket_ty r * Sockaddr.stream
     val close : t -> unit
+    val listening_addr : t -> Sockaddr.stream
   end
 
   type (_, _, _) Resource.pi +=
@@ -277,6 +278,10 @@ let accept_fork ~sw (t : [> 'a listening_socket_ty] r) ~on_error handle =
          )
     )
 
+let listening_addr (type tag) (Resource.T (t, ops) : [> tag listening_socket_ty] r) =
+  let module X = (val (Resource.get ops Pi.Listening_socket)) in
+  X.listening_addr t
+
 let send (Resource.T (t, ops)) ?dst bufs =
   let module X = (val (Resource.get ops Pi.Datagram_socket)) in
   X.send t ?dst bufs

lib_eio/net.mli

@@ -167,6 +167,8 @@ val listen :
 
     The new socket will be closed when [sw] finishes, unless closed manually first.
 
+    On platforms that support this, passing port [0] will bind to a random port.
+
     For (non-abstract) Unix domain sockets, the path will be removed afterwards.
 
     @param backlog The number of pending connections that can be queued up (see listen(2)).
@@ -205,6 +207,8 @@ val accept_fork :
                     [on_error] is not called for {!Cancel.Cancelled} exceptions,
                     which do not need to be reported. *)
 
+val listening_addr : [> 'tag listening_socket_ty] r -> Sockaddr.stream
+
 (** {2 Running Servers} *)
 
 val run_server :
@@ -327,6 +331,7 @@ module Pi : sig
 
     val accept : t -> sw:Switch.t -> tag stream_socket_ty r * Sockaddr.stream
     val close : t -> unit
+    val listening_addr : t -> Sockaddr.stream
   end
 
   val listening_socket :

lib_eio_linux/eio_linux.ml

@@ -235,6 +235,11 @@ module Listening_socket = struct
     in
     let flow = (flow client :> _ Eio.Net.stream_socket) in
     flow, client_addr
+
+  let listening_addr fd =
+    Eio_unix.Fd.use fd
+      (fun fd -> Eio_unix.Net.sockaddr_of_unix_stream (Unix.getsockname fd))
+      ~if_closed:(fun () -> failwith "listening_addr: socket is closed")
 end
 
 let listening_handler = Eio_unix.Pi.listening_socket_handler (module Listening_socket)

lib_eio_posix/net.ml

@@ -36,6 +36,11 @@ module Listening_socket = struct
     in
     let flow = (Flow.of_fd client :> _ Eio.Net.stream_socket) in
     flow, client_addr
+
+  let listening_addr { fd; _ } =
+    Eio_unix.Fd.use fd
+      (fun fd -> Eio_unix.Net.sockaddr_of_unix_stream (Unix.getsockname fd))
+      ~if_closed:(fun () -> failwith "listening_addr: socket is closed")
 end
 
 let listening_handler = Eio_unix.Pi.listening_socket_handler (module Listening_socket)

lib_eio_windows/net.ml

@@ -36,6 +36,11 @@ module Listening_socket = struct
     in
     let flow = (Flow.of_fd client :> _ Eio.Net.stream_socket) in
     flow, client_addr
+
+  let listening_addr fd =
+    Eio_unix.Fd.use fd
+      (fun fd -> Eio_unix.Net.sockaddr_of_unix_stream (Unix.getsockname fd))
+      ~if_closed:(fun () -> failwith "listening_addr: socket is closed")
 end
 
 let listening_handler = Eio_unix.Pi.listening_socket_handler (module Listening_socket)