[ping2][PATCH][BZ #16077] Get canonical name in getaddrinfo from hosts file for AF_INET

[Siddhesh Poyarekar <siddhesh at redhat dot com>]

Ping!

On Tue, Nov 19, 2013 at 07:02:58PM +0530, Siddhesh Poyarekar wrote:
> Ping!
> 
> On Wed, Oct 23, 2013 at 03:34:31PM +0530, Siddhesh Poyarekar wrote:
> > Hi,
> > 
> > AF_INET lookup in hosts file uses _nss_files_gethostbyname2_r, which
> > is not capable of returning a canonical name if it has found one.
> > This change adds _nss_files_gethostbyname3_r, which wraps around
> > _nss_files_gethostbyname2_r and then returns result.h_name as the
> > canonical name.
> > 
> > The bug report has a test case that helps verify this patch.  Tested
> > on x86_64 and also verified that it doesn't break any current tests.
> > OK to commit?
> > 
> > Siddhesh
> > 
> > 	[BZ #16077]
> > 	* nss/Versions (libnss_files): Add
> > 	_nss_files_gethostbyname3_r.
> > 	* nss/nss_files/files-hosts.c (_nss_files_gethostbyname3_r):
> > 	New function.
> > 
> > diff --git a/nss/Versions b/nss/Versions
> > index d13d570..f8ababc 100644
> > --- a/nss/Versions
> > +++ b/nss/Versions
> > @@ -40,6 +40,7 @@ libnss_files {
> >      _nss_files_endhostent;
> >      _nss_files_gethostbyaddr_r;
> >      _nss_files_gethostbyname2_r;
> > +    _nss_files_gethostbyname3_r;
> >      _nss_files_gethostbyname4_r;
> >      _nss_files_gethostbyname_r;
> >      _nss_files_gethostent_r;
> > diff --git a/nss/nss_files/files-hosts.c b/nss/nss_files/files-hosts.c
> > index 6db2535..23d8fa2 100644
> > --- a/nss/nss_files/files-hosts.c
> > +++ b/nss/nss_files/files-hosts.c
> > @@ -365,6 +365,23 @@ DB_LOOKUP (hostbyaddr, ,,,
> >  	   }, const void *addr, socklen_t len, int af)
> >  #undef EXTRA_ARGS_VALUE
> >  
> > +enum nss_status
> > +_nss_files_gethostbyname3_r (const char *name, int af, struct hostent *result,
> > +			     char *buffer, size_t buflen, int *errnop,
> > +			     int *herrnop, int32_t *ttlp, char **canonp)
> > +{
> > +  enum nss_status status = _nss_files_gethostbyname2_r (name, af, result,
> > +							buffer, buflen,
> > +							errnop, herrnop);
> > +
> > +  /* For a successful lookup, the first name in /etc/hosts is the canonical
> > +     host name.  */
> > +  if (result && status == NSS_STATUS_SUCCESS)
> > +    *canonp = result->h_name;
> > +
> > +  return status;
> > +}
> > +
> >  
> >  enum nss_status
> >  _nss_files_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat,