Patchwork [1/2] qga: add guest-get-time command

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Submitter Lei Li
Date March 1, 2013, 9:32 a.m.
Message ID <1362130380-1895-2-git-send-email-lilei@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/224263/
State New
Headers show

Comments

Lei Li - March 1, 2013, 9:32 a.m.
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(+)
Eric Blake - March 1, 2013, 5:02 p.m.
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.
>
Lei Li - March 4, 2013, 7:39 a.m.
On 03/02/2013 01:02 AM, Eric Blake wrote:
> 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

Oh, good to know! :)
Thanks.

>> +#
>> +# 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.

Sure.

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

Patch

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;
+   return time_ns; 
+}
+
 typedef struct GuestFileHandle {
     uint64_t id;
     FILE *fh;
diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
index d91d903..563600c 100644
--- a/qga/qapi-schema.json
+++ b/qga/qapi-schema.json
@@ -83,6 +83,22 @@ 
 { 'command': 'guest-ping' }
 
 ##
+# @guest-get-time:
+#
+# Get the information about guest time relative to the Epoch
+# of 1970-01-01 in UTC/GMT.
+#
+# This command try to get the guest's notion of the current
+# time.
+#
+# Returns: Time in nanoseconds on success.
+#
+# Since 1.5
+##
+{ 'command': 'guest-get-time',
+  'returns': 'int' }
+
+##
 # @GuestAgentCommandInfo:
 #
 # Information about guest agent commands.