use EIO process API

ocaml-multicore/eio#472

dune-project

@@ -1,26 +1 @@
 (lang dune 3.6)
-
-(name ocaml_exec_shell)
-
-(generate_opam_files true)
-
-(source
- (github username/reponame))
-
-(authors "Author Name")
-
-(maintainers "Maintainer Name")
-
-(license LICENSE)
-
-(documentation https://url/to/documentation)
-
-(package
- (name ocaml_exec_shell)
- (synopsis "A short synopsis")
- (description "A longer description")
- (depends (ocaml (>= 5.0.0)) dune eio_main)
- (tags
-  (topics "to describe" your project)))
-
-; See the complete stanza docs at https://dune.readthedocs.io/en/stable/dune-files.html#dune-project

flake.nix

@@ -2,7 +2,12 @@
   inputs = {
     opam-nix.url = "github:tweag/opam-nix";
     flake-utils.url = "github:numtide/flake-utils";
+    opam-repository = {
+      url = "github:ocaml/opam-repository";
+      flake = false;
+    };
     opam-nix.inputs.nixpkgs.follows = "nixpkgs";
+    opam-nix.inputs.opam-repository.follows = "opam-repository";
   };
   outputs = { self, nixpkgs, flake-utils, opam-nix, ... }@inputs:
     let package = "ocaml_exec_shell";
@@ -16,6 +21,7 @@
         };
         query = {
           ocaml-base-compiler = "*";
+          ocamlfind = "1.9.5";
         };
         overlay = final: prev: {
           "${package}" = prev.${package}.overrideAttrs (_: {

ocaml_exec_shell.opam

@@ -30,3 +30,11 @@ build: [
   ]
 ]
 dev-repo: "git+https://github.com/username/reponame.git"
+pin-depends: [
+  # https://github.com/ocaml-multicore/eio/pull/472
+  ["eio.dev" "git+https://github.com/ocaml-multicore/eio.git#dd66ff981e15c1a75cea48f736ccdea83497f8ee"]
+  ["eio_main.dev" "git+https://github.com/ocaml-multicore/eio.git#dd66ff981e15c1a75cea48f736ccdea83497f8ee"]
+  ["eio_linux.dev" "git+https://github.com/ocaml-multicore/eio.git#dd66ff981e15c1a75cea48f736ccdea83497f8ee"]
+  ["eio_posix.dev" "git+https://github.com/ocaml-multicore/eio.git#dd66ff981e15c1a75cea48f736ccdea83497f8ee"]
+  ["eio_luv.dev" "git+https://github.com/ocaml-multicore/eio.git#dd66ff981e15c1a75cea48f736ccdea83497f8ee"]
+]

src/dune

@@ -1,5 +1,5 @@
 (executable
  (public_name ocaml_exec_shell)
  (name main)
- (libraries unix eio_main)
+ (libraries unix eio_main eio_linux)
  (foreign_stubs (language c) (names pty)))

src/main.ml

@@ -1,85 +1,25 @@
 
-let client ~stdout ~stdin pty =
-  let savedTio = Unix.tcgetattr Unix.stdin in
-
-  (* set raw mode *)
-  let tio = {
-    savedTio with
-      (* input modes *)
-      c_ignpar = true;
-      c_istrip = false;
-      c_inlcr = false;
-      c_igncr = false;
-      c_ixon = false;
-      (* c_ixany = false; *)
-      (* c_iuclc = false; *)
-      c_ixoff = false;
-
-      (* output modes *)
-      c_opost = false;
-
-      (* control modes *)
-      c_isig = false;
-      c_icanon = false;
-      c_echo = false;
-      c_echoe = false;
-      c_echok = false;
-      c_echonl = false;
-      (* c_iexten = false; *)
-
-      (* special characters *)
-      c_vmin = 1;
-      c_vtime = 0;
-    };
-  in Unix.tcsetattr Unix.stdin TCSADRAIN tio;
-
-  let exception Sigchld in
-  let sigchld = Eio.Condition.create () in
-  let handle_sigchld (_signum : int) = Eio.Condition.broadcast sigchld in
-  ignore (Sys.signal Sys.sigchld (Signal_handle handle_sigchld));
-
-  try
-    (* don't close PTY file descriptors *)
-    let close_unix = false in
-    Eio.Fiber.all [
-      (fun () -> Eio.Switch.run @@ fun sw ->
-        let sink = Eio_unix.FD.as_socket ~sw ~close_unix pty.Pty.masterfd in
-        Eio.Flow.copy stdin sink);
-      (fun () -> Eio.Switch.run @@ fun sw ->
-        let source = Eio_unix.FD.as_socket ~sw ~close_unix pty.Pty.masterfd in
-        Eio.Flow.copy source stdout
-      );
-      (fun () -> Eio.Condition.await_no_mutex sigchld; raise Sigchld);
-    ]
-    with
-    | Sigchld -> ();
-  (* restore tio *)
-  Unix.tcsetattr Unix.stdin TCSADRAIN savedTio
-
-let server pty =
-  Unix.close pty.Pty.masterfd;
-  Pty.switch_controlling_pty pty;
-  (* TODO Pty.window_size pty pty_window; *)
-  Unix.dup2 pty.Pty.slavefd Unix.stdin;
-  Unix.dup2 pty.Pty.slavefd Unix.stdout;
-  Unix.dup2 pty.Pty.slavefd Unix.stderr;
-  Unix.close pty.Pty.slavefd;
-  (* TODO get default shell from /etc/passwd *)
-  try Unix.execve "/run/current-system/sw/bin/bash"
-    (* login shell *)
-    [| "-bash"; |]
-    (Unix.unsafe_environment ())
-    (* [| "PATH=" ^ Unix.getenv "PATH" |];; *)
-  with Unix.Unix_error (x,_s,y) ->
-    print_endline (Printf.sprintf "%s: %s" y (Unix.error_message x));
-  Pty.close_pty pty
+let client ~stdout ~stdin ~write ~read =
+  Eio.Fiber.both
+    (fun () -> Eio.Flow.copy stdin write)
+    (fun () -> Eio.Flow.copy read stdout)
 
 let () =
   Eio_main.run @@ fun env ->
-  let pty = Pty.open_pty () in
-  let pid = Unix.fork () in
-  (* if child *)
-  if pid == 0 then
-    server pty
-  else
-    client ~stdout:(Eio.Stdenv.stdout env) ~stdin:(Eio.Stdenv.stdin env) pty
+  Eio.Switch.run @@ fun sw ->
+  (* Could use Eio_unix.pipe with higher level Eio process lib
+     but need Eio_linux.FD for Eio_linux.Low_level.Process.spawn *)
+  let child =
+    let action = Eio_posix.Low_level.Process.Fork_action.execve
+      "/run/current-system/sw/bin/bash"
+      ~argv:[| "-bash" |]
+      ~env:[||] in
+    Eio_linux.Low_level.Process.spawn ~sw [ action ] in
+  let readInpipe, _writeInpipe = Eio_unix.pipe sw in
+  let _readOutpipe, writeOutpipe = Eio_unix.pipe sw in
+  client
+    ~stdout:(Eio.Stdenv.stdout env)
+    ~stdin:(Eio.Stdenv.stdin env)
+    ~write:writeOutpipe
+    ~read:readInpipe;
+  ignore @@ Eio.Promise.await (Eio_linux.Low_level.Process.exit_status child);;