[dpdk-dev] [PATCH v3 5/8] examples/power: add json string handling
Hunt, David
david.hunt at intel.com
Tue Sep 25 17:15:43 CEST 2018
On 25/9/2018 3:15 PM, Burakov, Anatoly wrote:
> On 25-Sep-18 3:00 PM, Hunt, David wrote:
>>> Now you're removing those newlines you added in previous commit :)
>>>
>>
>> Fixed in previous patch in the next version.
>>
>>
>>>> if (pol->pkt.core_type == CORE_TYPE_VIRTUAL) {
>>>> /*
>>>> * If the cores in the policy are virtual, we need to map
>>>> them
>>>> @@ -295,8 +423,6 @@ apply_traffic_profile(struct policy *pol)
>>>> diff = get_pkt_diff(pol);
>>>> - RTE_LOG(INFO, CHANNEL_MONITOR, "Applying traffic profile\n");
>>>> -
>>>
>>> Here and in a few other places: these log message removals look to
>>> be unrelated to this commit. Also, in my experience, more logging is
>>> better than less logging, especially when something goes wrong -
>>> maybe instead of removing them, just switch the level to debug?
>>>
>>
>> Changed to Debug instead. Was causing quite a verbose output.
>
> Hopefully in a separate commit :)
>
Of Course. :)
>>
>>>> if (diff >= (pol->pkt.traffic_policy.max_max_packet_thresh)) {
>>>> for (count = 0; count < pol->pkt.num_vcpu; count++) {
>>>> if (pol->core_share[count].status != 1)
>>>> @@ -340,9 +466,6 @@ apply_time_profile(struct policy *pol)
>>>> if (pol->core_share[count].status != 1) {
>>>> power_manager_scale_core_max(
>>>> pol->core_share[count].pcpu);
>>>> - RTE_LOG(INFO, CHANNEL_MONITOR,
>>>
>>> <snip>
>>>
>>>> + int idx = 0;
>>>> + int indent = 0;
>>>> + do {
>>>> + n_bytes = read(chan_info->fd, &json_data[idx], 1);
>>>> + if (n_bytes == 0)
>>>> + break;
>>>> + if (json_data[idx] == '{')
>>>> + indent++;
>>>> + if (json_data[idx] == '}')
>>>> + indent--;
>>>
>>> What happens if someone sends a string with a "{" or "}" inside?
>>>
>>
>> If we get to the end of the buffer without a "}", it calls the
>> library to convert, will fail, and move on. No damage done (I hope).
>> Also, a short un-terminated (by "}") string will also exit when no
>> characters read.
>> So any invalid JSON string that's send to Jansson will fail to parse,
>> and the application will be ready for the next (hopefully valid) JSON
>> string.
>
> No, what i meant is something like this:
>
> { "json_value": "{"}
>
> According to JSON validator, this is a valid JSON string, but it will
> break your code :)
>
You are correct if this code was designed to be a general purpose JSON
string reader. However, it's only designed to take in strings for this
sample application, and they do not expect any brace characters embedded
within quotes. So I think it's OK for this use case. Patches welcome,
though! :)
Thanks,
Dave.
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