[xen stable-4.16] tools/ocaml/evtchn: Extend the init() binding with a cloexec flag

[patchbot@xxxxxxx]

commit c96f51bc3e7c166ebdfd4d75fc8a1808fc699ac2
Author:     Edwin Török <edvin.torok@xxxxxxxxxx>
AuthorDate: Thu Nov 3 14:50:38 2022 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Mon Dec 12 11:04:12 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@xxxxxxxxxx>
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Christian Lindig <christian.lindig@xxxxxxxxxx>
    (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-4.16