Re: [dpdk-dev] [PATCH] eal: fix strdup usages in internal config

[Kevin Traynor <ktraynor@redhat.com>]

On 01/31/2019 02:10 PM, Burakov, Anatoly wrote:
> On 31-Jan-19 11:21 AM, Kevin Traynor wrote:
>> On 01/10/2019 01:38 PM, Anatoly Burakov wrote:
>>> Currently, we use strdup in a few places to store command-line
>>> parameter values for certain internal config values. There are
>>> several issues with that.
>>>
>>> First of all, they're never freed, so memory ends up leaking
>>> either after EAL exit, or when these command-line options are
>>> supplied multiple times.
>>>
>>> Second of all, they're defined as `const char *`, so they
>>> *cannot* be freed even if we wanted to.
>>>
>>> Finally, strdup may return NULL, which will be stored in the
>>> config. For most fields, NULL is a valid value, but for the
>>> default prefix, the value is always expected to be valid.
>>>
>>> To fix all of this, three things are done. First, we change
>>> the definitions of these values to `char *` as opposed to
>>> `const char *`. This does not break the ABI, and previous
>>> code assumes constness (which is more restrictive), so it's
>>> safe to do so.
>>>
>>> Then, fix all usages of strdup to check return value, and add
>>> a cleanup function that will free the memory occupied by
>>> these strings, as well as freeing them before assigning a new
>>> value to prevent leaks when parameter is specified multiple
>>> times.
>>>
>>> And finally, add an internal API to query hugefile prefix, so
>>> that, absent of a valid value, a default value will be
>>> returned, and also fix up all usages of hugefile prefix to
>>> use this API instead of accessing hugefile prefix directly.
>>>
>>> Bugzilla ID: 108
>>>
>>
>> Hi Anatoly - this doesn't have stable or Fixes tags, but the bugzilla
>> was reported on 17.11. Is it for backport to stable branches?
>>
> 
> It can be. Whether it's worth the effort of backporting is not my call :)
> 

It's fine for 18.11 branch anyway, just needed a little help due to some
changed context. I will send diff to stable list as normal.