Re: [Qemu-devel] [PATCH V10 12/17] hmp: add function hmp_info_snapshots()

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

于 2013-3-30 7:04, Eric Blake 写道:
> On 03/22/2013 08:19 AM, Wenchao Xia wrote:
>>    This function will simply call qmp interface qmp_query_snapshots()
>> added in last commit and then dump information in monitor console.
>>    To get snapshot info, Now qemu and qemu-img both call block layer
>> function bdrv_query_snapshot_info_list() in their calling path, and
>> then they just translate the qmp object got to strings in stdout or
>> monitor console.
>>
>> Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
>> ---
>>   hmp.c |   42 ++++++++++++++++++++++++++++++++++++++++++
>>   hmp.h |    1 +
>>   2 files changed, 43 insertions(+), 0 deletions(-)
>>
>> diff --git a/hmp.c b/hmp.c
>> index b0a861c..c475d65 100644
>> --- a/hmp.c
>> +++ b/hmp.c
>> @@ -651,6 +651,48 @@ void hmp_info_tpm(Monitor *mon, const QDict *qdict)
>>       qapi_free_TPMInfoList(info_list);
>>   }
>>
>> +/* assume list is valid */
>> +static void monitor_dump_snapshotinfolist(Monitor *mon, SnapshotInfoList *list)
>> +{
>> +    SnapshotInfoList *elem;
>> +    char buf[256];
>> +
>> +    monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL));
>
> Are you sure that won't ever be truncated?  I'm pretty sure that I could
> come up with a scenario where I cause bdrv_snapshot_dump() to want to
> output more than 256 bytes of details.
>
   I hope not use dynamic buff for strings, how about check it as
following:

char buf[254] = 0;
monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL));
if (buf[254]) {
      monitor_printf(mon, "'string truncated'");
}
-- 
Best Regards

Wenchao Xia