Re: [Xen-devel] [PATCH 2 of 2] tools/ocaml: libxc bindings: Fix failwith_xc()

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2013-02-14 at 19:29 +0000, Andrew Cooper wrote:
> The static error_str[] buffer is not thread-safe, and 1024 bytes is
> unreasonably large.  Reduce to 256 bytes (which is still much larger than any
> current use), and move it to being a stack variable.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Looks plausible to me, but please could you cc xen-api@ for ocaml
changes so someone who knows ocaml can comment.

> 
> diff -r 1daa30509f1c -r 39ae53386eb2 tools/ocaml/libs/xc/xenctrl_stubs.c
> --- a/tools/ocaml/libs/xc/xenctrl_stubs.c
> +++ b/tools/ocaml/libs/xc/xenctrl_stubs.c
> @@ -51,21 +51,22 @@
>       i1 = (uint32_t) Int64_val(Field(input, 0)); \
>       i2 = ((Field(input, 1) == Val_none) ? 0xffffffff : (uint32_t) 
> Int64_val(Field(Field(input, 1), 0)));
>  
> -#define ERROR_STRLEN 1024
>  void failwith_xc(xc_interface *xch)
>  {
> -     static char error_str[ERROR_STRLEN];
> +     char error_str[256];
>       if (xch) {
>               const xc_error *error = xc_get_last_error(xch);
>               if (error->code == XC_ERROR_NONE)
> -                     snprintf(error_str, ERROR_STRLEN, "%d: %s", errno, 
> strerror(errno));
> +                     snprintf(error_str, sizeof(error_str),
> +                              "%d: %s", errno, strerror(errno));
>               else
> -                     snprintf(error_str, ERROR_STRLEN, "%d: %s: %s",
> -                              error->code,
> +                     snprintf(error_str, sizeof(error_str),
> +                              "%d: %s: %s", error->code,
>                                xc_error_code_to_desc(error->code),
>                                error->message);
>       } else {
> -             snprintf(error_str, ERROR_STRLEN, "Unable to open XC 
> interface");
> +             snprintf(error_str, sizeof(error_str),
> +                      "Unable to open XC interface");
>       }
>       caml_raise_with_string(*caml_named_value("xc.error"), error_str);
>  }



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel