Re: [Qemu-devel] [PATCH RFC v7 5/7] qemu-iotests: s390x: fix test 049

[tu bo <tubo@linux.vnet.ibm.com>]

Hello Max:

Xiao Guang Chen left IBM last week, and I took over this job. thanks for 
your comments :-)

On 04/24/2015 12:47 AM, Max Reitz wrote:
> On 23.04.2015 04:42, Xiao Guang Chen wrote:
>> From: Bo Tu <tubo@linux.vnet.ibm.com>
>
> Hm, why is Bo Tu the patch author, but doesn't have an S-o-b in the 
> commit message?
I created the patch, but faild to send out it via 'git send-email". So 
XiaoGuang sent the patch with his account on his machine. Perhaps that's 
the reason.
>> when creating an image qemu-img enable us specifying the size of the
>> image using -o size=xx options. But when we specify an invalid size
>> such as a negtive size then different platform gives different result.
>>
>> parse_option_size() function in util/qemu-option.c will be called to
>> parse the size, a cast was called in the function to cast the input
>> (saved as a double in the function) size to an unsigned int64 value,
>> when the input is a negtive value or exceeds the maximum of uint64, then
>> the result is undefined.
>>
>> Language spec 6.3.1.4 Real floating and integers:
>> the result of this assignment/cast is undefined if the float is not
>> in the open interval (-1, U<type>_MAX+1).
>
> Thank you for pointing to the specific section. I guess there are 
> always new things to discover in C...
>
>> Signed-off-by: Xiao Guang Chen <chenxg@linux.vnet.ibm.com>
>> ---
>>   tests/qemu-iotests/049.out | 10 ++++------
>>   util/qemu-option.c         |  5 +++++
>>   2 files changed, 9 insertions(+), 6 deletions(-)
>>
>> diff --git a/tests/qemu-iotests/049.out b/tests/qemu-iotests/049.out
>> index 9f93666..75d90b2 100644
>> --- a/tests/qemu-iotests/049.out
>> +++ b/tests/qemu-iotests/049.out
>> @@ -95,17 +95,15 @@ qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- -1024
>>   qemu-img: Image size must be less than 8 EiB!
>>     qemu-img create -f qcow2 -o size=-1024 TEST_DIR/t.qcow2
>> -qemu-img: qcow2 doesn't support shrinking images yet
>> -qemu-img: TEST_DIR/t.qcow2: Could not resize image: Operation not 
>> supported
>> -Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=-1024 encryption=off 
>> cluster_size=65536 lazy_refcounts=off refcount_bits=16
>> +qemu-img: Parameter 'size' expects a positive number and must not 
>> exceeds the maximum UINT64
>> +qemu-img: TEST_DIR/t.qcow2: Invalid options for file format 'qcow2'
>>     qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- -1k
>>   qemu-img: Image size must be less than 8 EiB!
>>     qemu-img create -f qcow2 -o size=-1k TEST_DIR/t.qcow2
>> -qemu-img: qcow2 doesn't support shrinking images yet
>> -qemu-img: TEST_DIR/t.qcow2: Could not resize image: Operation not 
>> supported
>> -Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=-1024 encryption=off 
>> cluster_size=65536 lazy_refcounts=off refcount_bits=16
>> +qemu-img: Parameter 'size' expects a positive number and must not 
>> exceeds the maximum UINT64
>> +qemu-img: TEST_DIR/t.qcow2: Invalid options for file format 'qcow2'
>>     qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- 1kilobyte
>>   qemu-img: Invalid image size specified! You may use k, M, G, T, P 
>> or E suffixes for
>> diff --git a/util/qemu-option.c b/util/qemu-option.c
>> index fda4e5f..1c50fa4 100644
>> --- a/util/qemu-option.c
>> +++ b/util/qemu-option.c
>> @@ -179,6 +179,11 @@ void parse_option_size(const char *name, const 
>> char *value,
>>         if (value != NULL) {
>>           sizef = strtod(value, &postfix);
>> +        if (sizef < 0 || sizef > UINT64_MAX) {
>> +            error_set(errp, QERR_INVALID_PARAMETER_VALUE, name, "a 
>> positive "
>> +                       "number and must not exceeds the maximum 
>> UINT64");
>
> I think Markus would like to see these error macros not getting used 
> anymore, so I think it should be dropped and the full string should be 
> given here. I'll let him do the arguing, though. :-)
>
> If you keep the macro, I'd propose "a non-negative number below 2^64" 
> (or actually give the decimal value of UINT64_MAX, using 'a 
> non-negative number not exceeding "%" PRIu64, UINT64_MAX'). Remember 
> that 0 is not positive, but still a valid choice.
Good suggestion. I'll change the error message like "a non-negative 
number not exceeding "%" PRIu64, UINT64_MAX')" in v8.
> If you drop the macro, I'd propose error_setg(errp, "'%s' must be a 
> non-negative number below 2^64", name) or, like it is now, 
> error_setg(errp, "Parameter '%s' expects a non-negative number below 
> 2^64", name).
>
> Max
>
>> +            return;
>> +        }
>>           switch (*postfix) {
>>           case 'T':
>>               sizef *= 1024;
>
>