[dpdk-dev] [PATCH v3 1/1] fbarray: get fbarrays from containerized secondary
Yasufumi Ogawa
yasufum.o at gmail.com
Fri Jul 12 04:22:37 CEST 2019
On 2019/07/11 22:14, Burakov, Anatoly wrote:
> On 11-Jul-19 12:57 PM, Yasufumi Ogawa wrote:
>> On 2019/07/11 19:53, Burakov, Anatoly wrote:
>>> On 11-Jul-19 11:31 AM, yasufum.o at gmail.com wrote:
>>>> From: Yasufumi Ogawa <ogawa.yasufumi at lab.ntt.co.jp>
>>>>
>>> <...>
>>>
>>>> + if (getpid() == 1) {
>>>> + FILE *hn_fp;
>>>> + hn_fp = fopen("/etc/hostname", "r");
>>>> + if (hn_fp == NULL) {
>>>> + RTE_LOG(ERR, EAL,
>>>> + "Cannot open '/etc/hostname' for secondary\n");
>>>> + return -1;
>>>> + }
>>>> +
>>>> + /* with docker, /etc/hostname just has one entry of
>>>> hostname */
>>>> + if (fscanf(hn_fp, "%s", proc_id) == EOF) {
>>>
>>> Apologies for not pointing this out earlier, but do i understand
>>> correctly that there's no bounds checking here, and fscanf() will
>>> write however many bytes it wants?
>> I understand "%s" is not appropriate. hostname is 12 bytes char and I
>> thought proc_id[16] is enough, but it is unsafe. In addition, hostname
>> can be defined by user with docker's option, so it should be enough
>> for user defined name.
>>
>> How do you think expecting max 32 chars of hostname and set boundary
>> "%32s" as following?
>>
>> proc_id[33]; /* define proc id from hostname less than 33 bytes. */
>> ...
>> if (fscanf(hn_fp, "%32s", proc_id) == EOF) {
>>
>
> As long as it takes NULL-termination into account as well, it should be
> OK. I can't recall off the top of my head if %32s includes NULL
> terminator (probably not?).
Do you agree if initialize with NULL chars to ensure proc_id is
NULL-terminated? As tested on my environment, "%Ns" sets next of Nth
char as NULL, but it seems more reliable.
proc_id[33] = { 0 };
Yasufumi
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