sunrpc: Always obtain AF_INET addresses from NSS [BZ #20964]

The new __libc_rpc_gethostbyname function calls gethostbyname2_r
with an AF_INET argument and is therefore not affected by the
RES_USE_INET6 flag.

Validated with the following test program, with and without
RES_OPTIONS=inet6, against a NFS server.  (Link with -lrpcsvc.)

#include <rpc/clnt.h>
#include <rpcsvc/mount.h>
#include <stdio.h>
#include <string.h>

static void
usage (char **argv)
{
  printf ("usage:\n"
          "  %1$s HOST getrpcport\n"
          "  %1$s HOST callrpc\n"
          "  %1$s HOST clnt_create\n",
          argv[0]);
}

static void
dump_exports (struct exportnode *exports)
{
  while (exports != NULL)
    {
      printf ("%s\n", exports->ex_dir);
      exports = exports->ex_next;
    }
}

int
main (int argc, char **argv)
{
  if (argc != 3)
    {
      usage (argv);
      return 1;
    }

  const char *host = argv[1];
  const char *command = argv[2];

  if (strcmp (command, "getrpcport") == 0)
    {
      int port = getrpcport (host, MOUNTPROG, MOUNTVERS, IPPROTO_UDP);
      printf ("getrpcport: %d\n", port);
    }
  else if (strcmp (command, "callrpc") == 0)
    {
      struct exportnode *exports = NULL;
      int ret = callrpc (host, MOUNTPROG, MOUNTVERS, MOUNTPROC_EXPORT,
                         (xdrproc_t) xdr_void, NULL,
                         (xdrproc_t) xdr_exports, (char *)&exports);
      if (ret != 0)
        {
          clnt_perrno (ret);
          puts ("");
          return 1;
        }
      dump_exports (exports);
    }
  else if (strcmp (command, "clnt_create") == 0)
    {
      CLIENT *client = clnt_create
        (host, MOUNTPROG, MOUNTVERS, "udp");
      if (client == NULL)
        {
          printf ("error: clnt_create failed\n");
          return 1;
        }
      struct exportnode *exports = NULL;
      int ret = CLNT_CALL (client, MOUNTPROC_EXPORT,
                           (xdrproc_t) xdr_void, NULL,
                           (xdrproc_t) xdr_exports, (char *)&exports,
                           ((struct timeval) {15, 0}));
      if (ret != 0)
        {
          clnt_perrno (ret);
          puts ("");
          return 1;
        }
      dump_exports (exports);
    }
  else
    {
      usage (argv);
      return 1;
    }

  return 0;
}

1 files changed, 20 insertions, 20 deletions

diff --git a/sunrpc/getrpcport.c b/sunrpc/getrpcport.c
index 07ee8c05cd..8fde0a9610 100644
--- a/sunrpc/getrpcport.c
+++ b/sunrpc/getrpcport.c
@@ -1,3 +1,21 @@
+/* Obtain the RPC port number for an RPC service on a host.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
 /*
  * Copyright (c) 2010, Oracle America, Inc.
  *
@@ -43,26 +61,8 @@ int
 getrpcport (const char *host, u_long prognum, u_long versnum, u_int proto)
 {
   struct sockaddr_in addr;
-  struct hostent hostbuf, *hp;
-  size_t buflen;
-  char *buffer;
-  int herr;
-
-  buflen = 1024;
-  buffer = __alloca (buflen);
-  while (__gethostbyname_r (host, &hostbuf, buffer, buflen, &hp, &herr) != 0
-	 || hp == NULL)
-    if (herr != NETDB_INTERNAL || errno != ERANGE)
-      return 0;
-    else
-      {
-	/* Enlarge the buffer.  */
-	buflen *= 2;
-	buffer = __alloca (buflen);
-      }
 
-  memcpy ((char *) &addr.sin_addr, hp->h_addr, hp->h_length);
-  addr.sin_family = AF_INET;
-  addr.sin_port = 0;
+  if (__libc_rpc_gethostbyname (host, &addr) != 0)
+    return 0;
   return pmap_getport (&addr, prognum, versnum, proto);
 }