xapi-storage-script: create directories tail-recursively

Avoid blowing up the stack when creating directories recursively

Signed-off-by: Pau Ruiz Safont <[email protected]>

ocaml/xapi-storage-script/main.ml

@@ -112,20 +112,24 @@ module Sys = struct
     List.filter (function "." | ".." -> false | _ -> true) listing
     |> Lwt.return
 
-  let rec mkdir_p ?(perm = 0o755) path =
-    file_kind ~follow_symlinks:false path >>= function
-    | Directory ->
-        Lwt.return_unit
-    | Regular | Other | Unknown ->
-        let msg =
-          Printf.sprintf
-            {|Could not create directory "%s": already exists and it's not a directory|}
-            path
-        in
-        Lwt.fail (Failure msg)
-    | Missing ->
-        let parent = Filename.dirname path in
-        mkdir_p ~perm parent >>= fun () -> Lwt_unix.mkdir path perm
+  let mkdir_p ?(perm = 0o755) path =
+    let rec loop acc path =
+      file_kind ~follow_symlinks:false path >>= function
+      | Directory ->
+          (* create directories, parents first *)
+          Lwt_list.iter_s (fun f -> f ()) acc
+      | Regular | Other | Unknown ->
+          let msg =
+            Printf.sprintf
+              {|Could not create directory "%s": already exists and it's not a directory|}
+              path
+          in
+          Lwt.fail (Failure msg)
+      | Missing ->
+          let parent = Filename.dirname path in
+          loop ((fun () -> Lwt_unix.mkdir path perm) :: acc) parent
+    in
+    loop [] path
 end
 
 module Signal = struct