Re: [Qemu-devel] [PATCH v10 2/3] quorum: implement bdrv_add_child() and bdrv_del_child()

[Changlong Xie <xiecl.fnst@cn.fujitsu.com>]

On 03/08/2016 12:02 AM, Max Reitz wrote:
> On 07.03.2016 17:02, Eric Blake wrote:
>> On 03/05/2016 11:13 AM, Max Reitz wrote:
>>
>>>> +    index = atoi(child->name + 9);
>>>
>>> Optional: Assert absence of an error:
>>>
>>
>> Indeed, atoi() is worthless, because it cannot do error detection.
>>
>>> unsigned long index;
>>> char *endptr;
>>>
>>> index = strtoul(child->name + 9, &endptr, 10);
>>> assert(index >= 0 && !*endptr);
>>
>> Still incorrect; you aren't handling errno properly for detecting all
>> errors.  Even better is to use qemu_strtoul(), which already handles
>> proper error detection.
>
> Yeah, I keep forgetting that it returns ULONG_MAX on range error...

Yes, we should limit the range to INT_MAX. How do you like the following 
codes, i just steal it from xen_host_pci_get_value().

int rc;
const char *endptr;
unsigned long value;

assert(!strncmp(child->name, "children.", 9));
rc = qemu_strtoul(child->name + 9, &endptr, 10, &value);
if (!rc) {
     assert(value <= INT_MAX);
     index = value;
} else {
     error_setg_errno(errp, -rc, "Failed to parse value '%s'",
                      child->name + 9);
     return;
}

Thanks
	-Xie

>
> Max
>