|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] libxl: ocaml: event management
commit fd8c37da4e75e92eb2b38283ab0cab1018de2feb
Author: Rob Hoes <rob.hoes@xxxxxxxxxx>
AuthorDate: Tue Dec 10 16:48:27 2013 +0000
Commit: Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Wed Dec 11 13:17:38 2013 +0000
libxl: ocaml: event management
Having bindings to the low-level functions libxl_osevent_register_hooks and
related, allows to run an event loop in OCaml; either one we write
ourselves,
or one that is available elsewhere.
The Lwt cooperative threads library (http://ocsigen.org/lwt/), which is
quite
popular these days, has an event loop that can be easily extended to poll
any
additional fds that we get from libxl. Lwt provides a "lightweight"
threading
model, which does not let you run any other (POSIX) threads in your
application, and therefore excludes an event loop implemented in the C
bindings.
Signed-off-by: Rob Hoes <rob.hoes@xxxxxxxxxx>
Acked-by: David Scott <dave.scott@xxxxxxxxxxxxx>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
tools/ocaml/libs/xl/xenlight.ml.in | 37 ++++
tools/ocaml/libs/xl/xenlight.mli.in | 38 ++++
tools/ocaml/libs/xl/xenlight_stubs.c | 354 ++++++++++++++++++++++++++++++++++
3 files changed, 429 insertions(+), 0 deletions(-)
diff --git a/tools/ocaml/libs/xl/xenlight.ml.in
b/tools/ocaml/libs/xl/xenlight.ml.in
index a281425..46106b5 100644
--- a/tools/ocaml/libs/xl/xenlight.ml.in
+++ b/tools/ocaml/libs/xl/xenlight.ml.in
@@ -25,10 +25,47 @@ external ctx_alloc: Xentoollog.handle -> ctx =
"stub_libxl_ctx_alloc"
external test_raise_exception: unit -> unit = "stub_raise_exception"
+type event =
+ | POLLIN (* There is data to read *)
+ | POLLPRI (* There is urgent data to read *)
+ | POLLOUT (* Writing now will not block *)
+ | POLLERR (* Error condition (revents only) *)
+ | POLLHUP (* Device has been disconnected (revents only) *)
+ | POLLNVAL (* Invalid request: fd not open (revents only). *)
+
external send_trigger : ctx -> domid -> trigger -> int -> unit =
"stub_xl_send_trigger"
external send_sysrq : ctx -> domid -> char -> unit = "stub_xl_send_sysrq"
external send_debug_keys : ctx -> string -> unit = "stub_xl_send_debug_keys"
+module Async = struct
+ type for_libxl
+ type event_hooks
+ type osevent_hooks
+
+ external osevent_register_hooks' : ctx -> 'a -> osevent_hooks =
"stub_libxl_osevent_register_hooks"
+ external osevent_occurred_fd : ctx -> for_libxl -> Unix.file_descr ->
event list -> event list -> unit = "stub_libxl_osevent_occurred_fd"
+ external osevent_occurred_timeout : ctx -> for_libxl -> unit =
"stub_libxl_osevent_occurred_timeout"
+
+ let osevent_register_hooks ctx ~user ~fd_register ~fd_modify
~fd_deregister ~timeout_register ~timeout_modify =
+ Callback.register "libxl_fd_register" fd_register;
+ Callback.register "libxl_fd_modify" fd_modify;
+ Callback.register "libxl_fd_deregister" fd_deregister;
+ Callback.register "libxl_timeout_register" timeout_register;
+ Callback.register "libxl_timeout_modify" timeout_modify;
+ osevent_register_hooks' ctx user
+
+ let async_register_callback ~async_callback =
+ Callback.register "libxl_async_callback" async_callback
+
+ external evenable_domain_death : ctx -> domid -> int -> unit =
"stub_libxl_evenable_domain_death"
+ external event_register_callbacks' : ctx -> 'a -> event_hooks =
"stub_libxl_event_register_callbacks"
+
+ let event_register_callbacks ctx ~user ~event_occurs_callback
~event_disaster_callback =
+ Callback.register "libxl_event_occurs_callback"
event_occurs_callback;
+ Callback.register "libxl_event_disaster_callback"
event_disaster_callback;
+ event_register_callbacks' ctx user
+end
+
let register_exceptions () =
Callback.register_exception "Xenlight.Error" (Error(ERROR_FAIL, ""))
diff --git a/tools/ocaml/libs/xl/xenlight.mli.in
b/tools/ocaml/libs/xl/xenlight.mli.in
index d663196..170e0e0 100644
--- a/tools/ocaml/libs/xl/xenlight.mli.in
+++ b/tools/ocaml/libs/xl/xenlight.mli.in
@@ -27,7 +27,45 @@ external ctx_alloc: Xentoollog.handle -> ctx =
"stub_libxl_ctx_alloc"
external test_raise_exception: unit -> unit = "stub_raise_exception"
+type event =
+ | POLLIN (* There is data to read *)
+ | POLLPRI (* There is urgent data to read *)
+ | POLLOUT (* Writing now will not block *)
+ | POLLERR (* Error condition (revents only) *)
+ | POLLHUP (* Device has been disconnected (revents only) *)
+ | POLLNVAL (* Invalid request: fd not open (revents only). *)
+
external send_trigger : ctx -> domid -> trigger -> int -> unit =
"stub_xl_send_trigger"
external send_sysrq : ctx -> domid -> char -> unit = "stub_xl_send_sysrq"
external send_debug_keys : ctx -> string -> unit = "stub_xl_send_debug_keys"
+module Async : sig
+ type for_libxl
+ type event_hooks
+ type osevent_hooks
+
+ val osevent_register_hooks : ctx ->
+ user:'a ->
+ fd_register:('a -> Unix.file_descr -> event list -> for_libxl
-> unit) ->
+ fd_modify:('a -> Unix.file_descr -> event list -> unit) ->
+ fd_deregister:('a -> Unix.file_descr -> unit) ->
+ timeout_register:('a -> int -> int -> for_libxl -> unit) ->
+ timeout_modify:('a -> unit) ->
+ osevent_hooks
+
+ external osevent_occurred_fd : ctx -> for_libxl -> Unix.file_descr ->
event list -> event list -> unit = "stub_libxl_osevent_occurred_fd"
+ external osevent_occurred_timeout : ctx -> for_libxl -> unit =
"stub_libxl_osevent_occurred_timeout"
+
+ val async_register_callback :
+ async_callback:(result:error option -> user:'a -> unit) ->
+ unit
+
+ external evenable_domain_death : ctx -> domid -> int -> unit =
"stub_libxl_evenable_domain_death"
+
+ val event_register_callbacks : ctx ->
+ user:'a ->
+ event_occurs_callback:('a -> Event.t -> unit) ->
+ event_disaster_callback:('a -> event_type -> string -> int ->
unit) ->
+ event_hooks
+end
+
diff --git a/tools/ocaml/libs/xl/xenlight_stubs.c
b/tools/ocaml/libs/xl/xenlight_stubs.c
index 4ea2047..39a9632 100644
--- a/tools/ocaml/libs/xl/xenlight_stubs.c
+++ b/tools/ocaml/libs/xl/xenlight_stubs.c
@@ -30,6 +30,8 @@
#include <libxl.h>
#include <libxl_utils.h>
+#include <unistd.h>
+
#include "caml_xentoollog.h"
#define Ctx_val(x)(*((libxl_ctx **) Data_custom_val(x)))
@@ -370,6 +372,35 @@ static char *String_option_val(value v)
#include "_libxl_types.inc"
+void async_callback(libxl_ctx *ctx, int rc, void *for_callback)
+{
+ CAMLparam0();
+ CAMLlocal2(error, tmp);
+ static value *func = NULL;
+ value *p = (value *) for_callback;
+
+ if (func == NULL) {
+ /* First time around, lookup by name */
+ func = caml_named_value("libxl_async_callback");
+ }
+
+ if (rc == 0)
+ error = Val_none;
+ else {
+ tmp = Val_error(rc);
+ error = Val_some(tmp);
+ }
+
+ /* for_callback is a pointer to a "value" that was malloc'ed and
+ * registered with the OCaml GC. The value is handed back to OCaml
+ * in the following callback, after which the pointer is unregistered
+ * and freed. */
+ caml_callback2(*func, error, *p);
+
+ caml_remove_global_root(p);
+ free(p);
+}
+
#define _STRINGIFY(x) #x
#define STRINGIFY(x) _STRINGIFY(x)
@@ -703,6 +734,329 @@ value stub_xl_send_debug_keys(value ctx, value keys)
CAMLreturn(Val_unit);
}
+
+/* Event handling */
+
+short Poll_val(value event)
+{
+ CAMLparam1(event);
+ short res = -1;
+
+ switch (Int_val(event)) {
+ case 0: res = POLLIN; break;
+ case 1: res = POLLPRI; break;
+ case 2: res = POLLOUT; break;
+ case 3: res = POLLERR; break;
+ case 4: res = POLLHUP; break;
+ case 5: res = POLLNVAL; break;
+ }
+
+ CAMLreturn(res);
+}
+
+short Poll_events_val(value event_list)
+{
+ CAMLparam1(event_list);
+ short events = 0;
+
+ while (event_list != Val_emptylist) {
+ events |= Poll_val(Field(event_list, 0));
+ event_list = Field(event_list, 1);
+ }
+
+ CAMLreturn(events);
+}
+
+value Val_poll(short event)
+{
+ CAMLparam0();
+ CAMLlocal1(res);
+
+ switch (event) {
+ case POLLIN: res = Val_int(0); break;
+ case POLLPRI: res = Val_int(1); break;
+ case POLLOUT: res = Val_int(2); break;
+ case POLLERR: res = Val_int(3); break;
+ case POLLHUP: res = Val_int(4); break;
+ case POLLNVAL: res = Val_int(5); break;
+ default: failwith_xl(ERROR_FAIL, "cannot convert poll event
value"); break;
+ }
+
+ CAMLreturn(res);
+}
+
+value add_event(value event_list, short event)
+{
+ CAMLparam1(event_list);
+ CAMLlocal1(new_list);
+
+ new_list = caml_alloc(2, 0);
+ Store_field(new_list, 0, Val_poll(event));
+ Store_field(new_list, 1, event_list);
+
+ CAMLreturn(new_list);
+}
+
+value Val_poll_events(short events)
+{
+ CAMLparam0();
+ CAMLlocal1(event_list);
+
+ event_list = Val_emptylist;
+ if (events & POLLIN)
+ event_list = add_event(event_list, POLLIN);
+ if (events & POLLPRI)
+ event_list = add_event(event_list, POLLPRI);
+ if (events & POLLOUT)
+ event_list = add_event(event_list, POLLOUT);
+ if (events & POLLERR)
+ event_list = add_event(event_list, POLLERR);
+ if (events & POLLHUP)
+ event_list = add_event(event_list, POLLHUP);
+ if (events & POLLNVAL)
+ event_list = add_event(event_list, POLLNVAL);
+
+ CAMLreturn(event_list);
+}
+
+int fd_register(void *user, int fd, void **for_app_registration_out,
+ short events, void *for_libxl)
+{
+ CAMLparam0();
+ CAMLlocalN(args, 4);
+ static value *func = NULL;
+ value *p = (value *) user;
+
+ if (func == NULL) {
+ /* First time around, lookup by name */
+ func = caml_named_value("libxl_fd_register");
+ }
+
+ args[0] = *p;
+ args[1] = Val_int(fd);
+ args[2] = Val_poll_events(events);
+ args[3] = (value) for_libxl;
+
+ caml_callbackN(*func, 4, args);
+ CAMLreturn(0);
+}
+
+int fd_modify(void *user, int fd, void **for_app_registration_update,
+ short events)
+{
+ CAMLparam0();
+ CAMLlocalN(args, 3);
+ static value *func = NULL;
+ value *p = (value *) user;
+
+ if (func == NULL) {
+ /* First time around, lookup by name */
+ func = caml_named_value("libxl_fd_modify");
+ }
+
+ args[0] = *p;
+ args[1] = Val_int(fd);
+ args[2] = Val_poll_events(events);
+
+ caml_callbackN(*func, 3, args);
+ CAMLreturn(0);
+}
+
+void fd_deregister(void *user, int fd, void *for_app_registration)
+{
+ CAMLparam0();
+ CAMLlocalN(args, 2);
+ static value *func = NULL;
+ value *p = (value *) user;
+
+ if (func == NULL) {
+ /* First time around, lookup by name */
+ func = caml_named_value("libxl_fd_deregister");
+ }
+
+ args[0] = *p;
+ args[1] = Val_int(fd);
+
+ caml_callbackN(*func, 2, args);
+ CAMLreturn0;
+}
+
+int timeout_register(void *user, void **for_app_registration_out,
+ struct timeval abs, void *for_libxl)
+{
+ CAMLparam0();
+ CAMLlocalN(args, 4);
+ static value *func = NULL;
+ value *p = (value *) user;
+
+ if (func == NULL) {
+ /* First time around, lookup by name */
+ func = caml_named_value("libxl_timeout_register");
+ }
+
+ args[0] = *p;
+ args[1] = Val_int(abs.tv_sec);
+ args[2] = Val_int(abs.tv_usec);
+ args[3] = (value) for_libxl;
+
+ caml_callbackN(*func, 4, args);
+ CAMLreturn(0);
+}
+
+int timeout_modify(void *user, void **for_app_registration_update,
+ struct timeval abs)
+{
+ CAMLparam0();
+ static value *func = NULL;
+ value *p = (value *) user;
+
+ if (func == NULL) {
+ /* First time around, lookup by name */
+ func = caml_named_value("libxl_timeout_modify");
+ }
+
+ caml_callback(*func, *p);
+ CAMLreturn(0);
+}
+
+void timeout_deregister(void *user, void *for_app_registration)
+{
+ failwith_xl(ERROR_FAIL, "timeout_deregister not yet implemented");
+ return;
+}
+
+value stub_libxl_osevent_register_hooks(value ctx, value user)
+{
+ CAMLparam2(ctx, user);
+ CAMLlocal1(result);
+ libxl_osevent_hooks *hooks;
+ value *p;
+
+ hooks = malloc(sizeof(*hooks));
+ if (!hooks)
+ failwith_xl(ERROR_NOMEM, "cannot allocate osevent hooks");
+ hooks->fd_register = fd_register;
+ hooks->fd_modify = fd_modify;
+ hooks->fd_deregister = fd_deregister;
+ hooks->timeout_register = timeout_register;
+ hooks->timeout_modify = timeout_modify;
+ hooks->timeout_deregister = timeout_deregister;
+
+ p = malloc(sizeof(value));
+ if (!p)
+ failwith_xl(ERROR_NOMEM, "cannot allocate value");
+ *p = user;
+ caml_register_global_root(p);
+
+ libxl_osevent_register_hooks(CTX, hooks, (void *) p);
+
+ result = caml_alloc(1, Abstract_tag);
+ *((libxl_osevent_hooks **) result) = hooks;
+
+ CAMLreturn(result);
+}
+
+value stub_libxl_osevent_occurred_fd(value ctx, value for_libxl, value fd,
+ value events, value revents)
+{
+ CAMLparam5(ctx, for_libxl, fd, events, revents);
+ libxl_osevent_occurred_fd(CTX, (void *) for_libxl, Int_val(fd),
+ Poll_events_val(events), Poll_events_val(revents));
+ CAMLreturn(Val_unit);
+}
+
+value stub_libxl_osevent_occurred_timeout(value ctx, value for_libxl)
+{
+ CAMLparam2(ctx, for_libxl);
+ libxl_osevent_occurred_timeout(CTX, (void *) for_libxl);
+ CAMLreturn(Val_unit);
+}
+
+struct user_with_ctx {
+ libxl_ctx *ctx;
+ value user;
+};
+
+void event_occurs(void *user, libxl_event *event)
+{
+ CAMLparam0();
+ CAMLlocalN(args, 2);
+ struct user_with_ctx *c_user = (struct user_with_ctx *) user;
+ static value *func = NULL;
+
+ if (func == NULL) {
+ /* First time around, lookup by name */
+ func = caml_named_value("libxl_event_occurs_callback");
+ }
+
+ args[0] = c_user->user;
+ args[1] = Val_event(event);
+ libxl_event_free(c_user->ctx, event);
+
+ caml_callbackN(*func, 2, args);
+ CAMLreturn0;
+}
+
+void disaster(void *user, libxl_event_type type,
+ const char *msg, int errnoval)
+{
+ CAMLparam0();
+ CAMLlocalN(args, 4);
+ struct user_with_ctx *c_user = (struct user_with_ctx *) user;
+ static value *func = NULL;
+
+ if (func == NULL) {
+ /* First time around, lookup by name */
+ func = caml_named_value("libxl_event_disaster_callback");
+ }
+
+ args[0] = c_user->user;
+ args[1] = Val_event_type(type);
+ args[2] = caml_copy_string(msg);
+ args[3] = Val_int(errnoval);
+
+ caml_callbackN(*func, 4, args);
+ CAMLreturn0;
+}
+
+value stub_libxl_event_register_callbacks(value ctx, value user)
+{
+ CAMLparam2(ctx, user);
+ CAMLlocal1(result);
+ struct user_with_ctx *c_user = NULL;
+ libxl_event_hooks *hooks;
+
+ c_user = malloc(sizeof(*c_user));
+ if (!c_user)
+ failwith_xl(ERROR_NOMEM, "cannot allocate user value");
+ c_user->user = user;
+ c_user->ctx = CTX;
+ caml_register_global_root(&c_user->user);
+
+ hooks = malloc(sizeof(*hooks));
+ if (!hooks)
+ failwith_xl(ERROR_NOMEM, "cannot allocate event hooks");
+ hooks->event_occurs_mask = LIBXL_EVENTMASK_ALL;
+ hooks->event_occurs = event_occurs;
+ hooks->disaster = disaster;
+
+ libxl_event_register_callbacks(CTX, hooks, (void *) c_user);
+ result = caml_alloc(1, Abstract_tag);
+ *((libxl_event_hooks **) result) = hooks;
+
+ CAMLreturn(result);
+}
+
+value stub_libxl_evenable_domain_death(value ctx, value domid, value user)
+{
+ CAMLparam3(ctx, domid, user);
+ libxl_evgen_domain_death *evgen_out;
+
+ libxl_evenable_domain_death(CTX, Int_val(domid), Int_val(user),
&evgen_out);
+
+ CAMLreturn(Val_unit);
+}
+
/*
* Local variables:
* indent-tabs-mode: t
--
generated by git-patchbot for /home/xen/git/xen.git#master
_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |