[tarantool-patches] Re: [PATCH] lua: pwd: fix passwd and group traversal

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

On 25/08/2019 13:07, Alexander Turenko wrote:
> On Fri, Aug 23, 2019 at 10:26:05PM +0200, Vladislav Shpilevoy wrote:
>> Hi! Thanks for the patch!
>>
>>> The primary reason of this commit is to overcome a startup hang on
>>> CentOS 6.
>>>
>>> https://github.com/tarantool/tarantool/issues/4428
>>> https://github.com/tarantool/tarantool/issues/4447
>>> https://github.com/tarantool/tarantool/issues/4271
>>> https://github.com/tarantool/tarantool/tree/Totktonada/gh-4447-fix-centos-6-startup-fail-full-ci
>>>
>>> Waiting for CI:
>>> https://gitlab.com/tarantool/tarantool/pipelines/77906160
>>>
>>> I manually verified that tarantool starts on CentOS 6 after the change.
>>> Also verified that the module can be used now on FreeBSD 12.0.
>>>
>>> I understood that the commit formally changes a behaviour that can be
>>> visible for a user: it allows to pass cdata<struct passwd> to
>>> pwd.getgr() and to pass cdata<struct group> to pwd.getgr(). It is
>>> unlikely that one will want to use it or will find this ability by an
>>> occasion. Maybe only with pwd.getpw(1LL) or so, but luajit will report
>>> an error in the case. My intention was to keep the commit short and
>>> avoid refactoring of the module code.
>>
>> But this module is not a rocket science, even its whole rewrite would
>> not be hard. Here the refactoring is quite simple, please, consider
>> my proposal on the branch and below. You can squash it or keep - anyway
>> LGTM. Note, I didn't test my 'fixes', so perhaps they are totally wrong.
>>
>> =========================================================================
> 
>> +local function pwtotable(pw)
>> +    return {
>>          name    = ffi.string(pw.pw_name),
>>          id      = tonumber(pw.pw_uid),
>>          group   = getgr(pw.pw_gid),
> 
> I did the exactly same, but then observed that getgr() call should not
> be part of pwtotable() function.

Why? It does not affect pw iterators.