From: "lihuisong (C)" <lihuisong@huawei.com>
To: "Bruce Richardson" <bruce.richardson@intel.com>,
"Morten Brørup" <mb@smartsharesystems.com>
Cc: <dev@dpdk.org>, <andrew.rybchenko@oktetlabs.ru>,
<huangdaode@huawei.com>, <liudongdong3@huawei.com>,
<fengchengwen@huawei.com>
Subject: Re: [PATCH V6 6/8] telemetry: support adding integer value as hexadecimal
Date: Fri, 16 Dec 2022 09:15:43 +0800 [thread overview]
Message-ID: <f09b33a0-4e9e-3ce6-ede5-fff30b5f24b8@huawei.com> (raw)
In-Reply-To: <Y5scQq+SZoAw/D4d@bricha3-MOBL.ger.corp.intel.com>
在 2022/12/15 21:08, Bruce Richardson 写道:
> On Thu, Dec 15, 2022 at 01:52:02PM +0100, Morten Brørup wrote:
>>> From: lihuisong (C) [mailto:lihuisong@huawei.com]
>>> Sent: Thursday, 15 December 2022 13.46
>>>
>>> 在 2022/12/15 20:24, Morten Brørup 写道:
>>>>> From: Bruce Richardson [mailto:bruce.richardson@intel.com]
>>>>> Sent: Thursday, 15 December 2022 13.16
>>>>>
>>>>> On Thu, Dec 15, 2022 at 01:00:40PM +0100, Morten Brørup wrote:
>>>>>>> From: lihuisong (C) [mailto:lihuisong@huawei.com]
>>>>>>> Sent: Thursday, 15 December 2022 12.28
>>>>>>>
>>>>>>> 在 2022/12/15 18:46, Bruce Richardson 写道:
>>>>>>>> On Thu, Dec 15, 2022 at 06:31:44PM +0800, Huisong Li wrote:
>>>>>>>>> Sometimes displaying a unsigned integer value as hexadecimal
>>>>> encoded
>>>>>>> style
>>>>>>>>> is more expected for human consumption, such as, offload
>>>>> capability
>>>>>>> and
>>>>>>>>> device flag. This patch introduces two APIs to add unsigned
>>>>> integer
>>>>>>> value
>>>>>>>>> as hexadecimal encoded string to array or dictionary. And user
>>>>> can
>>>>>>> choose
>>>>>>>>> whether the stored value is padding to the specified width.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Huisong Li <lihuisong@huawei.com>
>>>>>>>>> Acked-by: Morten Brørup <mb@smartsharesystems.com>
>>>>>>>>> Acked-by: Chengwen Feng <fengchengwen@huawei.com>
>>>>>>>>> ---
>>>>>>>>> lib/telemetry/rte_telemetry.h | 47 ++++++++++++++++++++++
>>>>>>>>> lib/telemetry/telemetry_data.c | 72
>>>>>>> ++++++++++++++++++++++++++++++++++
>>>>>>>>> lib/telemetry/version.map | 9 +++++
>>>>>>>>> 3 files changed, 128 insertions(+)
>>>>>>>>>
>>>>>>>> <snip>
>>>>>>>>> +/* To suppress compiler warning about format string. */
>>>>>>>>> +#if defined(RTE_TOOLCHAIN_GCC)
>>>>>>>>> +#pragma GCC diagnostic push
>>>>>>>>> +#pragma GCC diagnostic ignored "-Wformat-nonliteral"
>>>>>>>>> +#elif defined(RTE_TOOLCHAIN_CLANG)
>>>>>>>>> +#pragma clang diagnostic push
>>>>>>>>> +#pragma clang diagnostic ignored "-Wformat-nonliteral"
>>>>>>>>> +#endif
>>>>>>>>> +
>>>>>>>>> +static int
>>>>>>>>> +rte_tel_uint_to_hex_encoded_str(char *buf, uint16_t len,
>>>>> uint64_t
>>>>>>> val,
>>>>>> The "len" parameter should be size_t or unsigned int, not uint16_t.
>>>>>>
>>>>>> And as a personal preference, I would name it "buf_len" instead of
>>>>> "len".
>>>>>>>>> + uint8_t display_bitwidth)
>>>>>>>>> +{
>>>>>>>>> +#define RTE_TEL_UINT_HEX_FORMAT_LEN 16
>>>>>>>>> +
>>>>>>>>> + uint8_t spec_hex_width = (display_bitwidth + 3) / 4;
>>>>>>>>> + char format[RTE_TEL_UINT_HEX_FORMAT_LEN];
>>>>>>>>> +
>>>>>>>>> + /* Buffer needs to have room to contain the prefix '0x' and
>>>>> '\0'.
>>>>>>> */
>>>>>>>>> + if (len < spec_hex_width + 3)
>>>>>>>>> + return -EINVAL;
>>>>>>>>> +
>>>>>>>> This check is not sufficient, as display_bitwidth could be 0 for
>>>>>>> example,
>>>>>>>> and the actual printed number have up to 16 characters.
>>>>>>> Yes, you are right. What do you think of the following check?
>>>>>>>
>>>>>>> max_hex_width = display_bitwidth == 0 ? (sizeof(uint64_t) * 2) :
>>>>>>> spec_hex_width;
>>>>>>> if (len < max_hex_width + 3)
>>>>>>> return -EINVAL;
>>>>>> LGTM.
>>>>> That would work, but actually I think we should drop this check
>>>>> completely
>>>>> - see comment below.
>>>>>
>>>>>>>>> + if (display_bitwidth != 0) {
>>>>>>>>> + sprintf(format, "0x%%0%u" PRIx64, spec_hex_width);
>>>>>>>>> + sprintf(buf, format, val);
>>>>>> snprintf(format, sizeof(format), "0x%%0%u" PRIx64, spec_hex_width);
>>>>>> snprintf(buf, len, format, val);
>>>>>>
>>>>>>>>> + } else {
>>>>>>>>> + sprintf(buf, "0x%" PRIx64, val);
>>>>>> snprintf(buf, len, "0x%" PRIx64, val);
>>>>>>
>>>>>>>>> + }
>>>>>>>>> +
>>>>>>>> snprintf should always be used when printing to the buffer so as
>>>>> to
>>>>>>> avoid
>>>>>>>> overflow. The return value after snprintf should always be
>>>>> checked
>>>>>>> too.
>>>>>>> If check for buffer is sufficient, can the return value of
>>> snprintf
>>>>> not
>>>>>>> be checked?
>>>>>>> There are also many places in telemetry lib that are not checked
>>>>> for
>>>>>>> this return value.
>>>>>>> Do you have any principles for this?
>>>>>> You already check the buffer size before printf() into it, so I
>>> think
>>>>> it suffices. However, to keep automated code checkers happy, you
>>> could
>>>>> easily use snprintf() instead of printf(). (Sorry about not doing it
>>> in
>>>>> my example.)
>>>>>> I somewhat disagree with Bruce's suggestion to check the return
>>> value
>>>>> from snprintf() after checking that the buffer is large enough. It
>>>>> would be effectively dead code, which might cause some confusion. On
>>>>> the other hand, it might keep some automated code checkers happy. In
>>>>> this specific case here, I don't have a strong preference.
>>>>> Sure, you don't need 2 checks - we can either check the length at
>>> the
>>>>> start, or else check the length by looking for the return value from
>>>>> snprintf, but we don't need to do both.
>>>>>
>>>>> Given the slight complexity in determining the correct length of the
>>>>> printf
>>>>> for the initial size check, I think I would go with the approach of
>>>>> *not*
>>>>> checking the buffer initially and just check the snprintf return
>>> value.
>>>>> That would remove any possibility of us doing an incorrect length
>>>>> check, as
>>>>> was the case originally with this patch.
>>>> That sounds reasonable to me. Please do that.
>>> I think above check is necessary. Because snprintf returns the total
>>> length of string
>>> formated instead of negative when buffer size isn't sufficient. what do
>>> you think?
>> I had the same concern, so I looked it up.
>>
>> snprintf() returns the length that the string would have, regardless if it was truncated or not.
>>
>> In other words:
>>
>> If the string is truncated, snprintf() returns a value greater than the buffer length parameter given to it.
>>
>> It can be checked like this:
>>
>> if (snprintf(buf, len, "0x%" PRIx64, val) > len)
>> return -EINVAL;
>>
>> In my opinion, checking for negative return values from snprintf() is not necessary.
>>
> +1
> One nit, because of the \0, we need to check for ">=" len since a return val
> equal to length means the last character was truncated to make room for the
> \0.
ok, do this in this way.
next prev parent reply other threads:[~2022-12-16 1:15 UTC|newest]
Thread overview: 122+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-08 8:05 [PATCH 0/8] fix possible data truncation and conversion error Huisong Li
2022-12-08 8:05 ` [PATCH 1/8] telemetry: move to header to controllable range Huisong Li
2022-12-08 8:05 ` [PATCH 2/8] telemetry: add u32 telemetry data type API Huisong Li
2022-12-08 8:05 ` [PATCH 3/8] test: add test cases for u32 telemetry data API Huisong Li
2022-12-08 8:05 ` [PATCH 4/8] ethdev: fix possible data truncation and conversion error Huisong Li
2022-12-08 8:05 ` [PATCH 5/8] mempool: " Huisong Li
2022-12-08 8:05 ` [PATCH 6/8] cryptodev: fix possible data " Huisong Li
2022-12-08 8:05 ` [PATCH 7/8] mem: possible data truncation and " Huisong Li
2022-12-08 8:05 ` [PATCH 8/8] ethdev: telemetry convert capability related variable to hex Huisong Li
2022-12-08 10:55 ` Morten Brørup
2022-12-08 11:20 ` Bruce Richardson
2022-12-09 3:07 ` lihuisong (C)
2022-12-09 11:04 ` [PATCH V2 00/11] telemetry: add u32 value type and hex integer string API Huisong Li
2022-12-09 11:04 ` [PATCH V2 01/11] telemetry: move to header to controllable range Huisong Li
2022-12-09 11:04 ` [PATCH V2 02/11] telemetry: add u32 value type Huisong Li
2022-12-09 11:04 ` [PATCH V2 03/11] test: add test cases for adding u32 value API Huisong Li
2022-12-09 11:04 ` [PATCH V2 04/11] ethdev: fix possible data truncation and conversion error Huisong Li
2022-12-09 11:04 ` [PATCH V2 05/11] mempool: " Huisong Li
2022-12-09 11:04 ` [PATCH V2 06/11] cryptodev: fix possible data " Huisong Li
2022-12-09 11:04 ` [PATCH V2 07/11] mem: possible data truncation and " Huisong Li
2022-12-09 11:04 ` [PATCH V2 08/11] telemetry: refactor mapping betwween value and array type Huisong Li
2022-12-09 11:04 ` [PATCH V2 09/11] telemetry: support adding integer value as hexadecimal Huisong Li
2022-12-09 11:04 ` [PATCH V2 10/11] test: add test cases for adding hex integer values API Huisong Li
2022-12-09 11:04 ` [PATCH V2 11/11] ethdev: display capability values in hexadecimal format Huisong Li
2022-12-09 18:24 ` [PATCH V2 00/11] telemetry: add u32 value type and hex integer string API Morten Brørup
2022-12-12 6:23 ` lihuisong (C)
2022-12-11 9:02 ` fengchengwen
2022-12-12 6:42 ` [PATCH V3 " Huisong Li
2022-12-12 6:42 ` [PATCH V3 01/11] telemetry: move to header to controllable range Huisong Li
2022-12-12 6:42 ` [PATCH V3 02/11] telemetry: add u32 value type Huisong Li
2022-12-12 6:42 ` [PATCH V3 03/11] test: add test cases for adding u32 value API Huisong Li
2022-12-12 6:42 ` [PATCH V3 04/11] ethdev: fix possible data truncation and conversion error Huisong Li
2022-12-12 6:43 ` [PATCH V3 05/11] mempool: " Huisong Li
2022-12-12 6:43 ` [PATCH V3 06/11] cryptodev: fix possible data " Huisong Li
2022-12-12 6:43 ` [PATCH V3 07/11] mem: possible data truncation and " Huisong Li
2022-12-12 6:43 ` [PATCH V3 08/11] telemetry: refactor mapping betwween value and array type Huisong Li
2022-12-12 6:43 ` [PATCH V3 09/11] telemetry: support adding integer value as hexadecimal Huisong Li
2022-12-12 6:43 ` [PATCH V3 10/11] test: add test cases for adding hex integer values API Huisong Li
2022-12-12 6:43 ` [PATCH V3 11/11] ethdev: display capability values in hexadecimal format Huisong Li
2022-12-12 10:31 ` [PATCH V3 00/11] telemetry: add u32 value type and hex integer string API Bruce Richardson
2022-12-12 11:02 ` Morten Brørup
2022-12-12 11:20 ` Bruce Richardson
2022-12-12 12:03 ` Morten Brørup
2022-12-12 12:16 ` Bruce Richardson
2022-12-13 11:00 ` Morten Brørup
2022-12-13 17:12 ` Bruce Richardson
2022-12-13 3:02 ` lihuisong (C)
2022-12-13 10:15 ` [PATCH V4 0/9] telemetry: fix data truncation and conversion error and add hex integer API Huisong Li
2022-12-13 10:15 ` [PATCH V4 1/9] telemetry: move to header to controllable range Huisong Li
2022-12-13 17:10 ` Bruce Richardson
2022-12-14 2:44 ` lihuisong (C)
2022-12-13 10:15 ` [PATCH V4 2/9] ethdev: fix possible data truncation and conversion error Huisong Li
2022-12-13 10:15 ` [PATCH V4 3/9] mempool: " Huisong Li
2022-12-13 10:15 ` [PATCH V4 4/9] cryptodev: fix possible data " Huisong Li
2022-12-13 10:15 ` [PATCH V4 5/9] mem: possible data truncation and " Huisong Li
2022-12-13 10:15 ` [PATCH V4 6/9] telemetry: refactor mapping between value and array type Huisong Li
2022-12-13 16:57 ` Bruce Richardson
2022-12-14 2:46 ` lihuisong (C)
2022-12-13 10:15 ` [PATCH V4 7/9] telemetry: support adding integer value as hexadecimal Huisong Li
2022-12-13 17:09 ` Bruce Richardson
2022-12-14 2:44 ` lihuisong (C)
2022-12-14 7:28 ` Morten Brørup
2022-12-14 12:17 ` lihuisong (C)
2022-12-13 10:15 ` [PATCH V4 8/9] test: add test cases for adding hex integer value API Huisong Li
2022-12-13 10:15 ` [PATCH V4 9/9] ethdev: display capability values in hexadecimal format Huisong Li
2022-12-14 12:32 ` [PATCH V5 0/8] telemetry: fix data truncation and conversion error and add hex integer API Huisong Li
2022-12-14 12:32 ` [PATCH V5 1/8] telemetry: move to header to controllable range Huisong Li
2022-12-14 12:32 ` [PATCH V5 2/8] ethdev: fix possible data truncation and conversion error Huisong Li
2022-12-14 12:32 ` [PATCH V5 3/8] mempool: " Huisong Li
2022-12-14 12:32 ` [PATCH V5 4/8] cryptodev: fix possible data " Huisong Li
2022-12-14 12:32 ` [PATCH V5 5/8] mem: possible data truncation and " Huisong Li
2022-12-14 13:00 ` Morten Brørup
2022-12-15 1:11 ` lihuisong (C)
2022-12-15 7:04 ` Morten Brørup
2022-12-15 7:56 ` lihuisong (C)
2022-12-14 12:32 ` [PATCH V5 6/8] telemetry: support adding integer value as hexadecimal Huisong Li
2022-12-14 15:38 ` Bruce Richardson
2022-12-15 1:32 ` lihuisong (C)
2022-12-14 12:32 ` [PATCH V5 7/8] test: add test cases for adding hex integer value API Huisong Li
2022-12-14 12:32 ` [PATCH V5 8/8] ethdev: display capability values in hexadecimal format Huisong Li
2022-12-15 10:31 ` [PATCH V6 0/8] telemetry: fix data truncation and conversion error and add hex integer API Huisong Li
2022-12-15 10:31 ` [PATCH V6 1/8] telemetry: move to header to controllable range Huisong Li
2022-12-15 10:31 ` [PATCH V6 2/8] ethdev: fix possible data truncation and conversion error Huisong Li
2022-12-15 10:31 ` [PATCH V6 3/8] mempool: " Huisong Li
2022-12-15 10:31 ` [PATCH V6 4/8] cryptodev: fix possible data " Huisong Li
2022-12-15 10:31 ` [PATCH V6 5/8] mem: possible data truncation and " Huisong Li
2022-12-15 10:31 ` [PATCH V6 6/8] telemetry: support adding integer value as hexadecimal Huisong Li
2022-12-15 10:46 ` Bruce Richardson
2022-12-15 11:27 ` lihuisong (C)
2022-12-15 12:00 ` Morten Brørup
2022-12-15 12:15 ` Bruce Richardson
2022-12-15 12:24 ` Morten Brørup
2022-12-15 12:45 ` lihuisong (C)
2022-12-15 12:52 ` Morten Brørup
2022-12-15 13:08 ` Bruce Richardson
2022-12-16 1:15 ` lihuisong (C) [this message]
2022-12-15 10:31 ` [PATCH V6 7/8] test: add test cases for adding hex integer value API Huisong Li
2022-12-15 10:31 ` [PATCH V6 8/8] ethdev: display capability values in hexadecimal format Huisong Li
2022-12-16 1:54 ` [PATCH V7 0/8] telemetry: fix data truncation and conversion error and add hex integer API Huisong Li
2022-12-16 1:54 ` [PATCH V7 1/8] telemetry: move to header to controllable range Huisong Li
2022-12-16 1:54 ` [PATCH V7 2/8] ethdev: fix possible data truncation and conversion error Huisong Li
2022-12-16 1:54 ` [PATCH V7 3/8] mempool: " Huisong Li
2022-12-16 1:54 ` [PATCH V7 4/8] cryptodev: fix possible data " Huisong Li
2022-12-16 1:54 ` [PATCH V7 5/8] mem: possible data truncation and " Huisong Li
2022-12-16 1:54 ` [PATCH V7 6/8] telemetry: support adding integer value as hexadecimal Huisong Li
2022-12-16 1:54 ` [PATCH V7 7/8] test: add test cases for adding hex integer value API Huisong Li
2022-12-16 9:31 ` Bruce Richardson
2022-12-19 7:04 ` lihuisong (C)
2022-12-16 1:54 ` [PATCH V7 8/8] ethdev: display capability values in hexadecimal format Huisong Li
2022-12-19 7:06 ` [PATCH V8 0/8] telemetry: fix data truncation and conversion error and add hex integer API Huisong Li
2022-12-19 7:06 ` [PATCH V8 1/8] telemetry: move to header to controllable range Huisong Li
2022-12-19 7:06 ` [PATCH V8 2/8] ethdev: fix possible data truncation and conversion error Huisong Li
2022-12-19 7:06 ` [PATCH V8 3/8] mempool: " Huisong Li
2022-12-19 7:06 ` [PATCH V8 4/8] cryptodev: fix possible data " Huisong Li
2022-12-19 7:06 ` [PATCH V8 5/8] mem: possible data truncation and " Huisong Li
2022-12-19 7:06 ` [PATCH V8 6/8] telemetry: support adding integer value as hexadecimal Huisong Li
2022-12-19 9:19 ` Bruce Richardson
2022-12-19 7:06 ` [PATCH V8 7/8] test: add test cases for adding hex integer value API Huisong Li
2022-12-19 7:06 ` [PATCH V8 8/8] ethdev: display capability values in hexadecimal format Huisong Li
2023-01-16 12:06 ` [PATCH V8 0/8] telemetry: fix data truncation and conversion error and add hex integer API lihuisong (C)
2023-01-30 10:39 ` lihuisong (C)
2023-02-05 20:43 ` Thomas Monjalon
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