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

[Eric Blake <eblake@redhat.com>]

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On 03/01/2013 02:32 AM, Lei Li wrote:
> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
> ---
>  qga/commands-posix.c | 16 ++++++++++++++++
>  qga/qapi-schema.json | 16 ++++++++++++++++
>  2 files changed, 32 insertions(+)
> 
> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
> index 0ad73f3..f159e25 100644
> --- a/qga/commands-posix.c
> +++ b/qga/commands-posix.c
> @@ -119,6 +119,22 @@ void qmp_guest_shutdown(bool has_mode, const char *mode, Error **err)
>      /* succeded */
>  }
>  
> +int64_t qmp_guest_get_time(Error **errp)
> +{
> +   int ret;
> +   qemu_timeval tq;
> +   int64_t time_ns;
> +
> +   ret = qemu_gettimeofday(&tq);
> +   if (ret < 0) {
> +       error_setg_errno(errp, errno, "Failed to get time");
> +       return -1;
> +   }
> +
> +   time_ns = tq.tv_sec * 1000000000LL + tq.tv_usec * 1000;

Is it worth a sanity check that the tv_sec scaling doesn't overflow?  Of
course, that won't happen until far into the future (well beyond the
2038 overflow of 32-bit seconds since Epoch), so it won't hit in OUR
lifetime, so I can look the other way.

>  
>  ##
> +# @guest-get-time:
> +#
> +# Get the information about guest time relative to the Epoch
> +# of 1970-01-01 in UTC/GMT.

UTC and GMT are not the same thing.  I'd drop the '/GMT'.
http://www.diffen.com/difference/GMT_vs_UTC

> +#
> +# This command try to get the guest's notion of the current
> +# time.

This sentence is redundant with the first one, and has grammar issues.
Drop it.

> +#
> +# Returns: Time in nanoseconds on success.
> +#
> +# Since 1.5
> +##
> +{ 'command': 'guest-get-time',
> +  'returns': 'int' }
> +
> +##
>  # @GuestAgentCommandInfo:
>  #
>  # Information about guest agent commands.
> 

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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