ucs: properly remove the unix socket when a signal is received

When using a unix socket to serve µCS, the file would not be removed
when the server was shut down.  Teach µCS to catch sigints and sigterms,
and call unlink on the socket if it exists.

Signed-off-by: Alban Gruin <alban at pa1ch dot fr>

3 files changed, 14 insertions, 4 deletions

diff --git a/src/server.ml b/src/server.ml
index 2c1c4b9..d3cf00e 100644
--- a/src/server.ml
+++ b/src/server.ml
@@ -47,7 +47,7 @@ let respond ?(mime="text/html; charset=utf-8") ?(status=`OK) body =
   let headers = Header.init_with "Content-Type" mime in
   Server.respond_string ~status ~body ~headers ()
 
-let serve base_url celcat_url mode =
+let serve base_url celcat_url mode stop =
   let fetch = fetch celcat_url in
   let callback _conn req _body =
     let meth = Request.meth req and
@@ -75,4 +75,4 @@ let serve base_url celcat_url mode =
     | _ ->
        Server.respond_string
          ~status:`Method_not_allowed ~body:"Method not allowed\n" () in
-  Server.create ~mode (Server.make ~callback ())
+  Server.create ~stop ~mode (Server.make ~callback ())
diff --git a/src/server.mli b/src/server.mli
index af3f0e8..cf3bac2 100644
--- a/src/server.mli
+++ b/src/server.mli
@@ -15,4 +15,4 @@
  *    along with ucs.  If not, see <http://www.gnu.org/licenses/>.
  *)
 
-val serve : string -> Uri.t -> Conduit_lwt_unix.server -> unit Lwt.t
+val serve : string -> Uri.t -> Conduit_lwt_unix.server -> unit Lwt.t -> unit Lwt.t
diff --git a/src/ucs.ml b/src/ucs.ml
index 3b6027c..84d5988 100644
--- a/src/ucs.ml
+++ b/src/ucs.ml
@@ -49,7 +49,17 @@ let () =
         mode = match socket with
       | Some s -> `Unix_domain_socket (`File s)
       | None -> `TCP (`Port port) in
-    Lwt_main.run (Server.serve base_url celcat_uri mode) in
+    let stop, r = Lwt.wait () in
+    Lwt_unix.on_signal Sys.sigint
+      (fun _ -> Lwt.wakeup r ()) |> ignore;
+    Lwt_unix.on_signal Sys.sigterm
+      (fun _ -> Lwt.wakeup r ()) |> ignore;
+    Lwt_main.run (
+      Lwt.finalize
+        (fun () -> Server.serve base_url celcat_uri mode stop)
+        (fun () -> match socket with
+           | Some s -> Lwt_unix.unlink s
+           | None -> Lwt.return_unit)) in
   let cmd =
     let doc = "micro celcatsanitizer: convert celcat \
                calendar to ICS files, on the fly." and