Re: [Qemu-devel] [PATCH v2 1/2] blockdev: Error out on negative throttling option values

[Eric Blake]

On 01/13/2016 03:17 AM, Alberto Garcia wrote:
> On Wed 13 Jan 2016 01:52:29 AM CET, Fam Zheng wrote:
> 
>> The implicit casting from unsigned int to double changes negative values
>> into large positive numbers and accepts them.  We should instead print
>> an error.
>>
>> Check the number range so this case is catched and reported.

s/catched/caught/

> 
> I still don't know why qemu_opt_get_number() convert silently negative
> numbers into positive ones, shouldn't it just fail with an "invalid
> parameter" error?

Passing -1 as a synonym for ULLONG_MAX can be convenient.  But rejecting
it outright rather than doing wraparound wouldn't hurt libvirt too badly.

> 
>> +#define THROTTLE_VALUE_MAX 1000000000000000L
> 
> This is larger than LONG_MAX in 32-bit systems, I don't know if you need
> to use LL instead.

You do need LL, not for C99, but for older compilers (hello mingw).

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

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