Re: [Qemu-devel] [PATCH 1/2] qga: add windows implementation for guest-get-time

[mdroth <mdroth@linux.vnet.ibm.com>]

On Thu, Mar 14, 2013 at 11:05:52PM +0800, Lei Li wrote:
> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
> ---
>  qga/commands-win32.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/qga/commands-win32.c b/qga/commands-win32.c
> index 7e8ecb3..b395bd5 100644
> --- a/qga/commands-win32.c
> +++ b/qga/commands-win32.c
> @@ -22,6 +22,12 @@
>  #define SHTDN_REASON_FLAG_PLANNED 0x80000000
>  #endif
> 
> +/* multiple of 100 nanoseconds elapsed between windows baseline
> +   (1/1/1601) and Unix Epoch (1/1/1970), accounting for leap years */
> +#define W32_FT_OFFSET (10000000ULL * 60 * 60 * 24 * \
> +                       (365 * (1970 - 1601) +       \
> +                        (1970 - 1601) / 4 - 3))
> +
>  static void acquire_privilege(const char *name, Error **err)
>  {
>      HANDLE token;
> @@ -108,6 +114,29 @@ void qmp_guest_shutdown(bool has_mode, const char *mode, Error **err)
>      }
>  }
> 
> +int64_t qmp_guest_get_time(Error **errp)
> +{
> +    SYSTEMTIME ts = {0};
> +    int64_t time_ns;
> +    FILETIME tf;
> +
> +    GetSystemTime(&ts);
> +    if (ts.wYear < 1601 || ts.wYear > 30827) {
> +        error_setg(errp, "Failed to get time");
> +        return -1;
> +    }
> +
> +    if (!SystemTimeToFileTime(&ts, &tf)) {
> +        error_setg_errno(errp, errno, "Failed to convert system time");

I missed this is well, SystemTimeToFileTime() doesn't set errno, but if
this is the only change needed I can fix this up in my tree.

> +        return -1;
> +    }
> +
> +    time_ns = ((((int64_t)tf.dwHighDateTime << 32) | tf.dwLowDateTime)
> +                - W32_FT_OFFSET) * 100;
> +
> +    return time_ns;
> +}
> +
>  int64_t qmp_guest_file_open(const char *path, bool has_mode, const char *mode, Error **err)
>  {
>      error_set(err, QERR_UNSUPPORTED);
> -- 
> 1.7.11.7
>