Re: [Qemu-devel] [PATCH 3/5] scripts: qmp-shell: allow single-quotes in JSON expressions

[John Snow <jsnow@redhat.com>]

On 04/22/2015 10:34 AM, Eric Blake wrote:
> On 04/21/2015 08:02 PM, John Snow wrote:
>> As a convenience for the user, replace any single quotes given
>> with double quotes so that the data will deserialize correctly
>> via json.loads().
>>
>> Signed-off-by: John Snow <jsnow@redhat.com>
>> ---
>>   scripts/qmp/qmp-shell | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/scripts/qmp/qmp-shell b/scripts/qmp/qmp-shell
>> index 5347f89..d7cb33d 100755
>> --- a/scripts/qmp/qmp-shell
>> +++ b/scripts/qmp/qmp-shell
>> @@ -129,7 +129,7 @@ class QMPShell(qmp.QEMUMonitorProtocol):
>>
>>               < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
>>           """
>> -        cmdargs = cmdline.split()
>> +        cmdargs = cmdline.replace("'", '"').split()
>
> This replaces ALL single quotes, even if they would otherwise be
> escaped.  That is, if I pass foo="a\'\"b", it will probably be corrupted.
>
> qmp-shell exists mainly as a convenience for testing, and I doubt
> testers are likely to want to use unbalanced quotes as contents of
> strings, so I can give a weak:
> Reviewed-by: Eric Blake <eblake@redhat.com>
>
> But it's still worth thinking about whether there is a more robust
> solution to be used.
>

Oh, hmm. I naively assumed that such quotes weren't permissable within 
the namespace for any valid QMP commands, but...

There's a lot of simplifying assumptions within qmp-shell already and I 
was really hoping to avoid re-architecting the parser where I just 
wanted to add a few "hit and run" improvements.

This patch could be dropped if it poses a serious problem; mostly I 
wanted to ensure that QMP commands could be entered as they are 
displayed (with single quotes!)

I'll look briefly to see if there's a quick win-button for converting 
the quotes in a "safe" way.

--js