[PATCH] Fix the FreeBSD build

[Jeremy Allison]

On Thu, Jun 08, 2017 at 07:47:49AM +1200, Andrew Bartlett wrote:
> On Wed, 2017-06-07 at 10:17 -0700, Jeremy Allison wrote:
> > On Wed, Jun 07, 2017 at 10:09:50PM +1200, Andrew Bartlett via samba-technical wrote:
> > >  }
> > > +#elif (!defined(STRERROR_R_XSI_NOT_GNU))
> > > +#undef strerror_r
> > > +int rep_strerror_r(int errnum, char *buf, size_t buflen)
> > > +{
> > > +	char *s = strerror_r(errnum, buf, buflen);
> > > +	if (s == NULL) {
> > > +		/* Shouldn't happen, should always get a string */
> > > +		return EINVAL;
> > > +	} else if (s != buf) {
> > > +		strlcpy(buf, s, buflen);
> > > +		if (strlen(s) > buflen - 1) {
> > > +			return ERANGE;
> > > +		}
> > 
> > Minor nit - the ERANGE check should be *before*
> > the strlcpy, that way we don't touch *buf if we're
> > returning an error.
> 
> It was deliberate, but I've not checked the actual behaviour of the
> official call and the manpage is unclear which has precedence.  

Yeah I'm pretty sure that behavior (writing into *buf on ERANGE)
is wrong though. "Thou shalt never mess with args on error" is
pretty baked into POSIX :-).

> Could you do that, as sadly this is becoming a massive time sink at
> this point, and Volker's 'just give up and go back to strerror()' patch
> is already in?
> 
> The untested idea was that it would always write something, as error
> checking by callers of strerror_r seems unlikely, and not initialising
> the buffer seems even less expected. 

I'll take a look.