[glibc] inet: Remove strdupa from nrl_domainname()

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b3c68b10afddf160c09c6862341b7fcfcaac901c

commit b3c68b10afddf160c09c6862341b7fcfcaac901c
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Wed Nov 10 15:26:52 2021 -0300

    inet: Remove strdupa from nrl_domainname()
    
    We can use the already in place scratch_buffer.
    
    Checked on x86_64-linux-gnu.
    
    Reviewed-by: DJ Delorie <dj@redhat.com>

Diff:
---
 inet/getnameinfo.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/inet/getnameinfo.c b/inet/getnameinfo.c
index 5965912c9e..d3387dd16a 100644
--- a/inet/getnameinfo.c
+++ b/inet/getnameinfo.c
@@ -118,15 +118,15 @@ nrl_domainname_core (struct scratch_buffer *tmpbuf)
       else
 	{
 	  /* We need to preserve the hostname.  */
-	  const char *hstname = strdupa (tmpbuf->data);
-	  while (__gethostbyname_r (hstname, &th,
-				    tmpbuf->data,
-				    tmpbuf->length,
+	  size_t hstnamelen = strlen (tmpbuf->data) + 1;
+	  while (__gethostbyname_r (tmpbuf->data, &th,
+				    tmpbuf->data + hstnamelen,
+				    tmpbuf->length - hstnamelen,
 				    &h, &herror))
 	    {
 	      if (herror == NETDB_INTERNAL && errno == ERANGE)
 		{
-		  if (!scratch_buffer_grow (tmpbuf))
+		  if (!scratch_buffer_grow_preserve (tmpbuf))
 		    return;
 		}
 	      else