Mailing List Archive

[xen stable-4.17] tools/ocaml/evtchn: Extend the init() binding with a cloexec flag
commit c7cf603836e40de1b4a6ca7d1d52736eb4a10327
Author: Edwin Török <edvin.torok@citrix.com>
AuthorDate: Thu Nov 3 14:50:38 2022 +0000
Commit: Andrew Cooper <andrew.cooper3@citrix.com>
CommitDate: Tue Dec 20 13:13:40 2022 +0000

tools/ocaml/evtchn: Extend the init() binding with a cloexec flag

For live update, oxenstored wants to clear CLOEXEC on the evtchn handle, so it
survives the execve() into the new oxenstored.

Have the new interface match how cloexec works in other Ocaml standard
libraries.

Signed-off-by: Edwin Török <edvin.torok@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
(cherry picked from commit 9bafe4a53306e7aa2ce6ffc96f7477c6f329f7a7)
---
tools/ocaml/libs/eventchn/xeneventchn.ml | 5 ++++-
tools/ocaml/libs/eventchn/xeneventchn.mli | 9 ++++++---
tools/ocaml/libs/eventchn/xeneventchn_stubs.c | 10 +++++++---
3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/tools/ocaml/libs/eventchn/xeneventchn.ml b/tools/ocaml/libs/eventchn/xeneventchn.ml
index be4de82f46..c16fdd4674 100644
--- a/tools/ocaml/libs/eventchn/xeneventchn.ml
+++ b/tools/ocaml/libs/eventchn/xeneventchn.ml
@@ -16,7 +16,10 @@

type handle

-external init: unit -> handle = "stub_eventchn_init"
+external _init: bool -> handle = "stub_eventchn_init"
+
+let init ?(cloexec=true) () = _init cloexec
+
external fdopen: Unix.file_descr -> handle = "stub_eventchn_fdopen"
external fd: handle -> Unix.file_descr = "stub_eventchn_fd"

diff --git a/tools/ocaml/libs/eventchn/xeneventchn.mli b/tools/ocaml/libs/eventchn/xeneventchn.mli
index 98b3c86f37..870429b6b5 100644
--- a/tools/ocaml/libs/eventchn/xeneventchn.mli
+++ b/tools/ocaml/libs/eventchn/xeneventchn.mli
@@ -43,9 +43,12 @@ val to_int: t -> int

val of_int: int -> t

-val init: unit -> handle
-(** Return an initialised event channel interface. On error it
- will throw a Failure exception. *)
+val init: ?cloexec:bool -> unit -> handle
+(** [init ?cloexec ()]
+ Return an initialised event channel interface.
+ The default is to close the underlying file descriptor
+ on [execve], which can be overriden with [~cloexec:false].
+ On error it will throw a Failure exception. *)

val fdopen: Unix.file_descr -> handle
(** Return an initialised event channel interface, from an already open evtchn
diff --git a/tools/ocaml/libs/eventchn/xeneventchn_stubs.c b/tools/ocaml/libs/eventchn/xeneventchn_stubs.c
index 7bdf711bc1..aa8a69cc1e 100644
--- a/tools/ocaml/libs/eventchn/xeneventchn_stubs.c
+++ b/tools/ocaml/libs/eventchn/xeneventchn_stubs.c
@@ -50,14 +50,18 @@ static struct custom_operations xenevtchn_ops = {
.compare_ext = custom_compare_ext_default, /* Can't compare */
};

-CAMLprim value stub_eventchn_init(void)
+CAMLprim value stub_eventchn_init(value cloexec)
{
- CAMLparam0();
+ CAMLparam1(cloexec);
CAMLlocal1(result);
xenevtchn_handle *xce;
+ unsigned int flags = 0;
+
+ if ( !Bool_val(cloexec) )
+ flags |= XENEVTCHN_NO_CLOEXEC;

caml_enter_blocking_section();
- xce = xenevtchn_open(NULL, 0);
+ xce = xenevtchn_open(NULL, flags);
caml_leave_blocking_section();

if (xce == NULL)
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.17