Re: [PATCH] util: win32: Write hex value when can't get error message

[Markus Armbruster <armbru@redhat.com>]

Kostiantyn Kostiuk <kkostiuk@redhat.com> writes:

> g_win32_error_message - translate a Win32 error code
> (as returned by GetLastError()) into the corresponding message.
>
> In the same time, we call error_setg_win32_internal with
> error codes from different Windows componets like VSS or
> Performance monitor that provides different codes and
> can't be converted with g_win32_error_message.

Are these error codes from GetLastError()?

>                                                In this
> case, the empty suffix will be returned so error will be
> masked.
>
> QGA error example:
>  - before changes:
>   {"error": {"class": "GenericError", "desc": "failed to add D:\\ to snapshot set: "}}
>  - after changes:
>   {"error": {"class": "GenericError", "desc": "failed to add D:\\ to snapshot set: unknown Windows error 0x8004230e"}}

Exact reproducer?

> Signed-off-by: Kostiantyn Kostiuk <kkostiuk@redhat.com>
> ---
>  util/error.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/util/error.c b/util/error.c
> index daea2142f3..b1342558ae 100644
> --- a/util/error.c
> +++ b/util/error.c
> @@ -188,6 +188,11 @@ void error_setg_win32_internal(Error **errp,
>  
>      if (win32_err != 0) {
>          suffix = g_win32_error_message(win32_err);
> +        // g_win32_error_message() failed
> +        if (!suffix[0]) {
> +            g_free(suffix);
> +            suffix = g_strdup_printf("unknown Windows error 0x%x", win32_err);
> +        }
>      }
>  
>      va_start(ap, fmt);