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, 2 insertions, 21 deletions

diff --git a/sunrpc/clnt_simp.c b/sunrpc/clnt_simp.c
index d612df09a0..0ecb64ca7b 100644
--- a/sunrpc/clnt_simp.c
+++ b/sunrpc/clnt_simp.c
@@ -61,7 +61,6 @@ callrpc (const char *host, u_long prognum, u_long versnum, u_long procnum,
   struct callrpc_private_s *crp = callrpc_private;
   struct sockaddr_in server_addr;
   enum clnt_stat clnt_stat;
-  struct hostent hostbuf, *hp;
   struct timeval timeout, tottimeout;
 
   if (crp == 0)
@@ -84,10 +83,6 @@ callrpc (const char *host, u_long prognum, u_long versnum, u_long procnum,
     }
   else
     {
-      size_t buflen;
-      char *buffer;
-      int herr;
-
       crp->valid = 0;
       if (crp->socket != RPC_ANYSOCK)
 	{
@@ -100,25 +95,11 @@ callrpc (const char *host, u_long prognum, u_long versnum, u_long procnum,
 	  crp->client = NULL;
 	}
 
-      buflen = 1024;
-      buffer = __alloca (buflen);
-      while (__gethostbyname_r (host, &hostbuf, buffer, buflen,
-				&hp, &herr) != 0
-	     || hp == NULL)
-	if (herr != NETDB_INTERNAL || errno != ERANGE)
-	  return (int) RPC_UNKNOWNHOST;
-	else
-	  {
-	    /* Enlarge the buffer.  */
-	    buflen *= 2;
-	    buffer = __alloca (buflen);
-	  }
+      if (__libc_rpc_gethostbyname (host, &server_addr) != 0)
+	return (int) get_rpc_createerr().cf_stat;
 
       timeout.tv_usec = 0;
       timeout.tv_sec = 5;
-      memcpy ((char *) &server_addr.sin_addr, hp->h_addr, hp->h_length);
-      server_addr.sin_family = AF_INET;
-      server_addr.sin_port = 0;
       if ((crp->client = clntudp_create (&server_addr, (u_long) prognum,
 			  (u_long) versnum, timeout, &crp->socket)) == NULL)
 	return (int) get_rpc_createerr().cf_stat;