search for: caml_enter_blocking_section

Since OCaml 4 the old and confusing caml_enter_blocking_section and caml_leave_blocking_section calls have been replaced with caml_release_runtime_system and caml_acquire_runtime_system (in that order). Use the new names. --- generator/OCaml.ml | 5 +++-- ocaml/guestfs-c.c | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/generator/OC...

...+ CAMLlocal2 (rv, v); + + caml_leave_blocking_section (); + + rv = caml_callback2_exn (list_exports_fn, Val_bool (readonly), + Val_bool (is_tls)); + if (Is_exception_result (rv)) { + nbdkit_error ("%s", caml_format_exception (Extract_exception (rv))); + caml_enter_blocking_section (); + CAMLreturnT (int, -1); + } + + /* Convert exports list into calls to nbdkit_add_export. */ + while (rv != Val_int (0)) { + const char *name, *desc; + + v = Field (rv, 0); /* export struct */ + name = String_val (Field (v, 0)); + desc = String_val (Field (v, 1)); +...

...+ CAMLlocal2 (rv, v); + + caml_leave_blocking_section (); + + rv = caml_callback2_exn (list_exports_fn, Val_bool (readonly), + Val_bool (is_tls)); + if (Is_exception_result (rv)) { + nbdkit_error ("%s", caml_format_exception (Extract_exception (rv))); + caml_enter_blocking_section (); + CAMLreturnT (int, -1); + } + + /* Convert exports list into calls to nbdkit_add_export. */ + while (rv != Val_emptylist) { + const char *name, *desc = NULL; + + v = Field (rv, 0); /* export struct */ + name = String_val (Field (v, 0)); + if (Is_block (Field (v, 1)))...

...t; + CAMLparam0 (); > + CAMLlocal1 (rv); > + > + caml_leave_blocking_section (); > + > + rv = caml_callback_exn (can_cache_fn, *(value *) h); > + if (Is_exception_result (rv)) { > + nbdkit_error ("%s", caml_format_exception (Extract_exception (rv))); > + caml_enter_blocking_section (); > + CAMLreturnT (int, -1); > + } > + > + caml_enter_blocking_section (); > + CAMLreturnT (int, Int_val (rv)); The not very obvious implicit assumption here is that the order of the Cache* flags in the OCaml code is the same as the numbering of the NBDKIT_CACHE_* flags in t...

...> +static int > +plugin_ocaml_errno_is_reliable (void *handle) > +{ > + return 0; > +} Actually OCaml is a real compiled language, and the call from C to OCaml code (via caml_callback_exn) is a short piece of asm which preserves errno. However you'll need to save errno around caml_enter_blocking_section since that unblocks and processes signals. IOW: static int pread_wrapper (void *h, void *buf, uint32_t count, uint64_t offset) { CAMLparam0 (); CAMLlocal3 (rv, strv, offsetv); + int saved_errno; ... rv = caml_callback3_exn (pread_fn, *(value *) h, strv, offsetv); + saved_err...

...static int +can_cache_wrapper (void *h) +{ + CAMLparam0 (); + CAMLlocal1 (rv); + + caml_leave_blocking_section (); + + rv = caml_callback_exn (can_cache_fn, *(value *) h); + if (Is_exception_result (rv)) { + nbdkit_error ("%s", caml_format_exception (Extract_exception (rv))); + caml_enter_blocking_section (); + CAMLreturnT (int, -1); + } + + caml_enter_blocking_section (); + CAMLreturnT (int, Int_val (rv)); +} + +static int +cache_wrapper (void *h, uint32_t count, uint64_t offset, uint32_t flags) +{ + CAMLparam0 (); + CAMLlocal4 (rv, countv, offsetv, flagsv); + + caml_leave_blocking_section...

...econnect_wrapper (int readonly) +{ + CAMLparam0 (); + CAMLlocal1 (rv); + + caml_leave_blocking_section (); + + rv = caml_callback_exn (preconnect_fn, Val_bool (readonly)); + if (Is_exception_result (rv)) { + nbdkit_error ("%s", caml_format_exception (Extract_exception (rv))); + caml_enter_blocking_section (); + CAMLreturnT (int, -1); + } + + caml_enter_blocking_section (); + CAMLreturnT (int, 1); +} + /*----------------------------------------------------------------------*/ /* set_* functions called from OCaml code at load time to initialize * fields in the plugin struct. @@ -815,6 +836,8...

This picks up python and ocaml. Some of our languages are lacking a number of bindings (for example, lua and perl lack .extents, so I didn't have anything to copy from), and I felt less comfortable with golang and rust. But for python and ocaml, I was able to test a working implementation. Eric Blake (2): python: Implement .list_exports and friends ocaml: Implement .list_exports and

No action required here as I have pushed this already, this is just for your information. Rich.

...ml_callback_exn) is a short piece of asm which > preserves errno. Which shows my lack of familiarity with OCaml; but I'm guessing that also means that OCaml comes with easy ways to directly set errno so that it will be visible from C. > > However you'll need to save errno around caml_enter_blocking_section > since that unblocks and processes signals. > > IOW: > > static int > pread_wrapper (void *h, void *buf, uint32_t count, uint64_t offset) > { > CAMLparam0 (); > CAMLlocal3 (rv, strv, offsetv); > + int saved_errno; > ... > rv = caml_callback...

...- caml_leave_blocking_section (); + bool in_blocking_section = (caml_state == NULL); + + if (in_blocking_section) + caml_leave_blocking_section (); event_callback_wrapper_locked (g, data, event, event_handle, flags, buf, buf_len, array, array_len); - caml_enter_blocking_section (); + if (in_blocking_section) + caml_enter_blocking_section (); } value -- 2.40.1

...455,7 +456,14 @@ pread_wrapper (void *h, void *buf, uint32_t count, uint64_t offset, CAMLreturnT (int, -1); } - memcpy (buf, String_val (strv), count); + len = caml_string_length (rv); + if (len < count) { + nbdkit_error ("buffer returned from pread is too small"); + caml_enter_blocking_section (); + CAMLreturnT (int, -1); + } + + memcpy (buf, String_val (rv), count); caml_enter_blocking_section (); CAMLreturnT (int, 0); diff --git a/plugins/ocaml/NBDKit.ml b/plugins/ocaml/NBDKit.ml index b03ff5a..14b9803 100644 --- a/plugins/ocaml/NBDKit.ml +++ b/plugins/ocaml/NBDKit.ml @@ -...

...desc = NULL; v = Field (rv, 0); /* export struct */ name = String_val (Field (v, 0)); - desc = String_val (Field (v, 1)); + if (Is_block (Field (v, 1))) + desc = String_val (Field (Field (v, 1), 0)); if (nbdkit_add_export (exports, name, desc) == -1) { caml_enter_blocking_section (); CAMLreturnT (int, -1); -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org

...atic int +thread_model_wrapper (void) +{ + CAMLparam0 (); + CAMLlocal1 (rv); + + caml_leave_blocking_section (); + + rv = caml_callback_exn (config_complete_fn, Val_unit); + if (Is_exception_result (rv)) { + nbdkit_error ("%s", caml_format_exception (Extract_exception (rv))); + caml_enter_blocking_section (); + CAMLreturnT (int, -1); + } + + caml_enter_blocking_section (); + CAMLreturnT (int, Int_val (rv)); +} + /*----------------------------------------------------------------------*/ /* set_* functions called from OCaml code at load time to initialize * fields in the plugin struct. */...

...| 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/generator/generator b/generator/generator index 92ce170..109fad6 100755 --- a/generator/generator +++ b/generator/generator @@ -5239,9 +5239,6 @@ let print_ocaml_binding (name, { args; optargs; ret }) = pr " caml_enter_blocking_section ();\n"; pr " }\n"; pr "\n"; - pr " if (valid_flag & LIBNBD_CALLBACK_FREE)\n"; - pr " free_root (NULL, user_data);\n"; - pr "\n"; pr " return ret;\n"; pr "}\n";...

...ld (rv, 0); /* export struct */ > name = String_val (Field (v, 0)); > - desc = String_val (Field (v, 1)); > + if (Is_block (Field (v, 1))) > + desc = String_val (Field (Field (v, 1), 0)); > if (nbdkit_add_export (exports, name, desc) == -1) { > caml_enter_blocking_section (); > CAMLreturnT (int, -1); Seems OK. I'm guessing this crashes? Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-builder quickly builds VMs from scratch http://libg...

Version 1 was here: https://www.redhat.com/archives/libguestfs/2019-April/msg00144.html Version 2 makes a couple of much larger changes: The OCaml patch changes the API of the pread method so it matches what other language bindings are already doing, ie. get the language plugin to return a newly allocated buffer, check it is long enough, copy out the data. The server patch implements a

...ort struct */ >> name = String_val (Field (v, 0)); >> - desc = String_val (Field (v, 1)); >> + if (Is_block (Field (v, 1))) >> + desc = String_val (Field (Field (v, 1), 0)); >> if (nbdkit_add_export (exports, name, desc) == -1) { >> caml_enter_blocking_section (); >> CAMLreturnT (int, -1); > > Seems OK. I'm guessing this crashes? Nope, it worked. So compared to your explanation above, my test for Some was Is_block, rather than Int_val(0). And I repeated Field(v,1) for getting to the 'Some "string"' rather...

...ernal_ocaml_buffer_to_bytes\" external of_bytes : bytes -> t = \"nbd_internal_ocaml_buffer_of_bytes\" external size : t -> int = \"nbd_internal_ocaml_buffer_size\" @@ -5244,10 +5239,8 @@ let print_ocaml_binding (name, { args; optargs; ret }) = pr " caml_enter_blocking_section ();\n"; pr " }\n"; pr "\n"; - pr " if (valid_flag & LIBNBD_CALLBACK_FREE) {\n"; - pr " caml_remove_generational_global_root ((value *)user_data);\n"; - pr " free (user_data);\n"; - pr "...

...tion ();\n"; let c_argnames = List.flatten (List.map name_of_arg args) in - pr " %s_%s_wrapper_locked (%s);\n" name cb_name + pr " ret = %s_%s_wrapper_locked (%s);\n" name cb_name (String.concat ", " c_argnames); pr " caml_enter_blocking_section ();\n"; + pr " return ret;\n"; pr "}\n" | _ -> () ) args; diff --git a/generator/states-reply-structured.c b/generator/states-reply-structured.c index e6c1a8a..c835713 100644 --- a/generator/states-reply-structured.c +++ b/generator/states-reply-st...