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Re: [Libguestfs] [Hivex] [PATCH] Correct 32-bit to 64-bit call



On Wed, Aug 10, 2011 at 09:26:27PM -0700, Alex‎ Nelson wrote:
> Hello all,

> I found the below call while looking for the distinction between the
> OCaml-bound return types for int64_t and uint64_t.  I noticed that
> uint64_t is not among the return types in generator.ml, and some of
> the error tests appear to rely on the value being signed.  How would
> you recommend getting around the signed requirement in order to add
> an unsigned return type?  Some of the time functions I'd like to use
> (which seems to entail exposing a public API) call for an unsigned
> return type.

In some sense, for the C API & ABI it doesn't matter.  The bits in
int64_t and uint64_t are the same, it's just how you cast them.

So either we can add RUint64 (and your implementation looks fine, but
please present it as a separate patch).  Or we could just return
int64_t and callers could cast, which is not very elegant.

I notice that Windows itself only guarantees FILETIME up to year
9999-12-31 (because of convertibility to .Net's DateTime).  This is
well within the signed number, and if we're still using Windows in the
year 10000 then I despair for the human race anyway :-)

Rich.

> --Alex
> 
> 
> ---
>  generator/generator.ml |   46 +++++++++++++++++++++++++++++++++++-----------
>  1 files changed, 35 insertions(+), 11 deletions(-)
> 
> diff --git a/generator/generator.ml b/generator/generator.ml
> index c142a85..a6cc582 100755
> --- a/generator/generator.ml
> +++ b/generator/generator.ml
> @@ -56,6 +56,7 @@ and ret =
>    | RLenTypeVal                         (* See hivex_value_value. *)
>    | RInt32                              (* Returns int32. *)
>    | RInt64                              (* Returns int64. *)
> +  | RUInt64                             (* Returns uint64. *)
>  
>  and args = argt list                    (* List of parameters. *)
>  
> @@ -170,11 +171,6 @@ only know the \"real\" name of the root node by knowing which registry
>  file this hive originally comes from, which is knowledge that is
>  outside the scope of this library.";
>  
> -  "node_mtime", (RString, [AHive; ANode "node"]),
> -    "return the last-modified time of the node",
> -    "\
> -Return the last-modified time of the node.  Output is in ISO 8601 format.";
> -
>    "node_children", (RNodeList, [AHive; ANode "node"]),
>      "return children of node",
>      "\
> @@ -777,7 +773,6 @@ struct hivex_visitor {
>    int (*value_none) (hive_h *, void *opaque, hive_node_h, hive_value_h, hive_type t, size_t len, const char *key, const char *value);
>    int (*value_other) (hive_h *, void *opaque, hive_node_h, hive_value_h, hive_type t, size_t len, const char *key, const char *value);
>    int (*value_any) (hive_h *, void *opaque, hive_node_h, hive_value_h, hive_type t, size_t len, const char *key, const char *value);
> -  int (*node_mtime) (hive_h *h, void *writer_v, hive_node_h node, const char *last_modified);
>  };
>  
>  #define HIVEX_VISIT_SKIP_BAD 1
> @@ -813,6 +808,7 @@ and generate_c_prototype ?(extern = false) name style =
>     | RLenTypeVal -> pr "char *"
>     | RInt32 -> pr "int32_t "
>     | RInt64 -> pr "int64_t "
> +   | RUInt64 -> pr "uint64_t "
>    );
>    pr "%s (" name;
>    let comma = ref false in
> @@ -1033,7 +1029,7 @@ On error this returns -1 and sets errno.\n\n"
>  The value is returned as an array of bytes (of length C<len>).
>  The value must be freed by the caller when it is no longer needed.
>  On error this returns NULL and sets errno.\n\n"
> -       | RInt32 | RInt64 -> ()
> +       | RInt32 | RInt64 | RUInt64 -> ()
>        );
>    ) functions;
>  
> @@ -1140,8 +1136,6 @@ all, set the function pointer to NULL.
>      */
>     int (*value_any) (hive_h *, void *opaque, hive_node_h, hive_value_h,
>           hive_type t, size_t len, const char *key, const char *value);
> -   int (*node_mtime) (hive_h *h, void *writer_v, hive_node_h node,
> -         const char *last_modified)
>   };
>  
>  =over 4
> @@ -1543,6 +1537,7 @@ and generate_ocaml_prototype ?(is_external = false) name style =
>     | RLenTypeVal -> pr "hive_type * string"
>     | RInt32 -> pr "int32"
>     | RInt64 -> pr "int64"
> +   | RUInt64 -> pr "uint64"
>    );
>    if is_external then
>      pr " = \"ocaml_hivex_%s\"" name;
> @@ -1708,6 +1703,10 @@ static void raise_closed (const char *) Noreturn;
>          | RInt64 ->
>              pr "  errno = 0;\n";
>              pr "  int64_t r;\n";
> +            "-1 && errno != 0"
> +        | RUInt64 ->
> +            pr "  errno = 0;\n";
> +            pr "  uint64_t r;\n";
>              "-1 && errno != 0" in
>  
>        (* The libguestfs OCaml bindings call enter_blocking_section
> @@ -1779,7 +1778,8 @@ static void raise_closed (const char *) Noreturn;
>             pr "  rv = copy_type_value (r, len, t);\n";
>             pr "  free (r);\n"
>         | RInt32 -> pr "  rv = caml_copy_int32 (r);\n"
> -       | RInt64 -> pr "  rv = caml_copy_int32 (r);\n"
> +       | RInt64 -> pr "  rv = caml_copy_int64 (r);\n"
> +       | RUInt64 -> pr "  rv = caml_copy_int64 (r);\n"
>        );
>  
>        pr "  CAMLreturn (rv);\n";
> @@ -2088,7 +2088,8 @@ sub open {
>  	 | RLenType
>  	 | RLenTypeVal
>  	 | RInt32
> -	 | RInt64 -> ()
> +	 | RInt64
> +	 | RUInt64 -> ()
>  	 | RNode ->
>  	     pr "\
>  This returns a node handle.\n\n"
> @@ -2159,6 +2160,7 @@ and generate_perl_prototype name style =
>     | RLenTypeVal -> pr "($type, $data) = "
>     | RInt32 -> pr "$int32 = "
>     | RInt64 -> pr "$int64 = "
> +   | RUInt64 -> pr "$uint64 = "
>    );
>  
>    let args = List.tl (snd style) in
> @@ -2381,6 +2383,7 @@ DESTROY (h)
>  	 | RLenTypeVal -> pr "void\n"
>  	 | RInt32 -> pr "SV *\n"
>  	 | RInt64 -> pr "SV *\n"
> +	 | RUInt64 -> pr "SV *\n"
>  	);
>  
>  	(* Call and arguments. *)
> @@ -2595,6 +2598,21 @@ DESTROY (h)
>               pr "      RETVAL = my_newSVll (r);\n";
>               pr " OUTPUT:\n";
>               pr "      RETVAL\n"
> +
> +	 | RUInt64 ->
> +             pr "PREINIT:\n";
> +             pr "      uint64_t r;\n";
> +             pr "   CODE:\n";
> +	     pr "      errno = 0;\n";
> +             pr "      r = hivex_%s (%s);\n"
> +	       name (String.concat ", " c_params);
> +	     free_args ();
> +             pr "      if (r == -1 && errno != 0)\n";
> +             pr "        croak (\"%%s: %%s\", \"%s\", strerror (errno));\n"
> +	       name;
> +             pr "      RETVAL = my_newSVll (r);\n";
> +             pr " OUTPUT:\n";
> +             pr "      RETVAL\n"
>  	);
>  	pr "\n"
>        )
> @@ -2837,6 +2855,10 @@ put_val_type (char *val, size_t len, hive_type t)
>          | RInt64 ->
>              pr "  errno = 0;\n";
>              pr "  int64_t r;\n";
> +            "-1 && errno != 0"
> +        | RUInt64 ->
> +            pr "  errno = 0;\n";
> +            pr "  uint64_t r;\n";
>              "-1 && errno != 0" in
>  
>        (* Call and arguments. *)
> @@ -2999,6 +3021,8 @@ put_val_type (char *val, size_t len, hive_type t)
>             pr "  py_r = PyInt_FromLong ((long) r);\n"
>         | RInt64 ->
>             pr "  py_r = PyLong_FromLongLong (r);\n"
> +       | RUInt64 ->
> +           pr "  py_r = PyLong_FromLongLong (r);\n"
>        );
>        pr "  return py_r;\n";
>        pr "}\n";
> -- 
> 1.7.6
> 
> 
> 
> 
> On Aug 10, 2011, at 20:56 , Alex‎ Nelson wrote:
> 
> > ---
> > generator/generator.ml |    2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> > 
> > diff --git a/generator/generator.ml b/generator/generator.ml
> > index 31478cd..de911f1 100755
> > --- a/generator/generator.ml
> > +++ b/generator/generator.ml
> > @@ -1771,7 +1771,7 @@ static void raise_closed (const char *) Noreturn;
> >            pr "  rv = copy_type_value (r, len, t);\n";
> >            pr "  free (r);\n"
> >        | RInt32 -> pr "  rv = caml_copy_int32 (r);\n"
> > -       | RInt64 -> pr "  rv = caml_copy_int32 (r);\n"
> > +       | RInt64 -> pr "  rv = caml_copy_int64 (r);\n"
> >       );
> > 
> >       pr "  CAMLreturn (rv);\n";
> > -- 
> > 1.7.3.1
> > 
> > 
> > _______________________________________________
> > Libguestfs mailing list
> > Libguestfs redhat com
> > https://www.redhat.com/mailman/listinfo/libguestfs
> 
> 
> _______________________________________________
> Libguestfs mailing list
> Libguestfs redhat com
> https://www.redhat.com/mailman/listinfo/libguestfs

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming blog: http://rwmj.wordpress.com
Fedora now supports 80 OCaml packages (the OPEN alternative to F#)
http://cocan.org/getting_started_with_ocaml_on_red_hat_and_fedora


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