Hello,
On 19-11-2010, Goswin von Brederlow <goswin-...@web.de> wrote:
> Sylvain Le Gall <sylv...@le-gall.net> writes:
>
>> On 18-11-2010, Goswin von Brederlow <goswin-...@web.de> wrote:
>>> Hi,
>>>
>>> I'm looking for stubs for
>>>
>>> ssize_t sendmsg(int sockfd, const struct msghdr *msg, int flags);
>>> ssize_t recvmsg(int sockfd, struct msghdr *msg, int flags);
>>>
>>> Specifically I need those to send (among normal messages) an
>>> Unix.file_descr over a Unix Domain Socket.
>>>
>>> Does anyone know of a module that has them?
>>>
>>
>> If you don't find one and plan to write it yourself, this would be a
>> good addition to extunix:
>> http://extunix.forge.ocamlcore.org
>>
>> Regards,
>> Sylvain Le Gall
>
> I'm thinking of changing Unix.file_descr from int to a custom block
> (containing the FD) with finalizer. Unix.close would set the FD to -1
> and the finalizer gives an error if FD != -1 and closes it.
>
> Actually I want that tunable with 3 possible behaviours:
>
> type fd_leak_mode = Silent | Complain | Fail
> val set_leak_mode : fd_leak_mode -> unit = <fun>
>
> Silent just closes the FD if it is still open, Complain (default)
> outputs to stderr and closes it and Fail aborts.
>
> That would change most of the Unix module and mean a complete fork of it.
Not that much, if you proceed in another way. I think what you are
looking for is a fd leak detector?
Here is a small modules that I have written for this purpose:
File UnixExt.ml:
(** Count open/close call *)
IFNDEF NDBUG THEN
let fd_opened =
Hashtbl.create 13
;;
let fd_once_opened =
Hashtbl.create 13
;;
let fd_open fd fn out =
dbug_print
(fun () ->
Printf.sprintf "%s '%s'"
(if out then "open-out" else "open-in")
fn);
Hashtbl.add fd_opened fd (fn, out)
;;
let fd_close fd =
try
let (fn, out) as data =
Hashtbl.find fd_opened fd
in
dbug_print
(fun () ->
Printf.sprintf "%s '%s'"
(if out then "close-out" else "close-in")
fn);
Hashtbl.add fd_once_opened fd data;
Hashtbl.remove fd_opened fd;
with Not_found ->
begin
dbug_print
(fun () ->
let fn =
try
fst (Hashtbl.find fd_once_opened fd)
with Not_found ->
"unknown"
in
Printf.sprintf "Trying to close %s again" fn)
end
;;
let () =
at_exit
(fun () ->
let exit_error =
ref false
in
Hashtbl.iter
(fun fd (fn, out) ->
if fd <> Unix.stdin && fd <> Unix.stdout && fd <> Unix.stderr then
begin
Printf.eprintf "Not closed '%s' (out: %b)\n" fn out;
exit_error := true
end)
fd_opened;
Hashtbl.clear fd_opened;
if !exit_error then
exit 3
)
;;
let opened_files () =
let lst =
ref []
in
Hashtbl.iter
(fun _ e -> lst := e :: !lst)
fd_opened;
List.sort compare !lst;
ELSE
let fd_open _ _ _ =
()
;;
let fd_close _ =
()
;;
let opened_files () =
[]
;;
ENDIF
(** See UnixExt.mli *)
let to_file_descr_in fd =
fd_open fd "<converted>" false;
fd
;;
(** See UnixExt.mli *)
let to_file_descr_out fd =
fd_open fd "<converted>" true;
fd
;;
(** See UnixExt.mli *)
let close_in fd =
Unix.close fd;
fd_close fd
;;
(** See UnixExt.mli *)
let stdout =
fd_open Unix.stdout "<stdout>" true;
Unix.stdout
;;
[...override other functions that open/close fd...]
Then in the modules using this features, you just have to open UnixExt
after Unix...
You can even probably design a library that will transparently hide Unix
with a custom Unix module providing this feature.
>
> Would that be something for extunix too?
>
I don't think so. At least, this is not currently the purpose of
extunix...
Regards,
Sylvain Le Gall
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