Patch for memory leak in vfs_defaults.c

[Timur I. Bakeyev]

On 6 April 2018 at 22:55, Jeremy Allison via samba-technical <
samba-technical at lists.samba.org> wrote:

> On Fri, Apr 06, 2018 at 04:40:44PM -0400, Andrew Walker via
> samba-technical wrote:
> > Hi all,
> > I encountered an issue where several FreeNAS users on samba 4.7 were
> > experiencing memory leak resulting in single smbd process consuming all
> > available RAM and swap space. Disabling the getwd cache significantly
> > increased rate of leak, and enabling widelinks / disabling unix
> extensions
> > made the leak apparently stop. Investigation indicated that the leak was
> in
> > vfswrap_getwd().
> >
> > The attached patch resolved the issue.
>
> Oh god that's *embarassing*. Looks like my fault too, sorry.
>
> Thanks very much for finding that.
>
> Can you try the attached patch instead and confirm it fixes it,
> it's a smaller and simpler change.
>

I asked Andrew to change it this way, as it then fully mimics
`vfswrap_realpath()` function, which in a lot of aspects behaves the
same(and allocates malloc()ed buffer as well). Of course it's a matter of
taste,
but my idea was that we'd try to keep the style of the similar functions
also similar, which ease the reading of code.

With best regards,
Timur Bakeyev.