/* Copyright (C) 1997-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Thorsten Kukuk <kukuk@uni-paderborn.de>, 1997.

   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; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <string.h>

#include <rpcsvc/nis.h>

#include "nis_xdr.h"

#include "nis_intern.h"

#include <libnsl.h>

#include <shlib-compat.h>

nis_result *

nis_lookup (const_nis_name name, const unsigned int flags)

{

  nis_result *res = calloc (1, sizeof (nis_result));

  struct ns_request req;

  nis_name *names;

  nis_error status;

  int link_first_try = 0;

  int count_links = 0;	 /* We will follow only 16 links in the deep */

  int done = 0;

  int name_nr = 0;

  nis_name namebuf[2] = {NULL, NULL};

  if (res == NULL)

    return NULL;

  if ((flags & EXPAND_NAME) && (name[strlen (name) - 1] != '.'))

    {

      names = nis_getnames (name);

      if (names == NULL)

	{

	  NIS_RES_STATUS (res) = NIS_NAMEUNREACHABLE;

	  return res;

	}

    }

  else

    {

      names = namebuf;

      names[0] = (nis_name)name;

    }

  req.ns_name = names[0];

  while (!done)

    {

      dir_binding bptr;

      directory_obj *dir = NULL;

      req.ns_object.ns_object_len = 0;

      req.ns_object.ns_object_val = NULL;

      status = __prepare_niscall (req.ns_name, &dir, &bptr, flags);

      if (__glibc_unlikely (status != NIS_SUCCESS))

	{

	  NIS_RES_STATUS (res) = status;

	  goto out;

	}

      do

	{

	  static const struct timeval RPCTIMEOUT = {10, 0};

	  enum clnt_stat result;

	again:

	  result = clnt_call (bptr.clnt, NIS_LOOKUP,

			      (xdrproc_t) _xdr_ns_request,

			      (caddr_t) &req, (xdrproc_t) _xdr_nis_result,

			      (caddr_t) res, RPCTIMEOUT);

	  if (result != RPC_SUCCESS)

	    status = NIS_RPCERROR;

	  else

	    {

	      status = NIS_SUCCESS;

	      if (NIS_RES_STATUS (res) == NIS_SUCCESS)

		{

		    if (__type_of (NIS_RES_OBJECT (res)) == NIS_LINK_OBJ

			&& (flags & FOLLOW_LINKS)) /* We are following links */

		      {

			/* if we hit the link limit, bail */

			if (count_links > NIS_MAXLINKS)

			  {

			    NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;

			    break;

			  }

			++count_links;

			req.ns_name =

			  strdupa (NIS_RES_OBJECT (res)->LI_data.li_name);

			/* The following is a non-obvious optimization.  A

			   nis_freeresult call would call xdr_free as the

			   following code.  But it also would unnecessarily

			   free the result structure.  We avoid this here

			   along with the necessary tests.  */

			xdr_free ((xdrproc_t) _xdr_nis_result, (char *) res);

			memset (res, '\0', sizeof (*res));

			link_first_try = 1; /* Try at first the old binding */

			goto again;

		      }

		}

	      else

		if (NIS_RES_STATUS (res) == NIS_SYSTEMERROR

		    || NIS_RES_STATUS (res) == NIS_NOSUCHNAME

		    || NIS_RES_STATUS (res) == NIS_NOT_ME)

		  {

		    if (link_first_try)

		      {

			__nisbind_destroy (&bptr);

			nis_free_directory (dir);

			/* Otherwise __nisfind_server will not do anything.  */

			dir = NULL;

			if (__nisfind_server (req.ns_name, 1, &dir, &bptr,

					      flags & ~MASTER_ONLY)

			    != NIS_SUCCESS)

			  goto out;

		      }

		    else

		      if (__nisbind_next (&bptr) != NIS_SUCCESS)

			{

			  /* No more servers to search.  Try parent.  */

			  const char *ndomain = __nis_domain_of (req.ns_name);

			  req.ns_name = strdupa (ndomain);

			  if (strcmp (req.ns_name, ".") == 0)

			    {

			      NIS_RES_STATUS (res) = NIS_NAMEUNREACHABLE;

			      goto out;

			    }

			  __nisbind_destroy (&bptr);

			  nis_free_directory (dir);

			  dir = NULL;

			  status = __prepare_niscall (req.ns_name, &dir,

						      &bptr, flags);

			  if (__glibc_unlikely (status != NIS_SUCCESS))

			    {

			      NIS_RES_STATUS (res) = status;

			      goto out;

			    }

			  goto again;

			}

		    while (__nisbind_connect (&bptr) != NIS_SUCCESS)

		      {

			if (__nisbind_next (&bptr) != NIS_SUCCESS)

			  {

			    nis_free_directory (dir);

			    goto out;

			  }

		      }

		    goto again;

		  }

	      break;

	    }

	  link_first_try = 0; /* Set it back */

	}

      while ((flags & HARD_LOOKUP) && status == NIS_RPCERROR);

      __nisbind_destroy (&bptr);

      nis_free_directory (dir);

      if (status != NIS_SUCCESS)

	{

	  NIS_RES_STATUS (res) = status;

	  goto out;

	}

      switch (NIS_RES_STATUS (res))

	{

	case NIS_PARTIAL:

	case NIS_SUCCESS:

	case NIS_S_SUCCESS:

	case NIS_LINKNAMEERROR: /* We follow to max links */

	case NIS_UNAVAIL: /* NIS+ is not installed, or all servers are down */

	  ++done;

	  break;

	default:

	  /* Try the next domainname if we don't follow a link */

	  if (count_links)

	    {

	      free (req.ns_name);

	      NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;

	      ++done;

	      break;

	    }

	  ++name_nr;

	  if (names[name_nr] == NULL)

	    {

	      ++done;

	      break;

	    }

	  req.ns_name = names[name_nr];

	  break;

	}

    }

 out:

  if (names != namebuf)

    nis_freenames (names);

  return res;

}

libnsl_hidden_nolink_def (nis_lookup, GLIBC_2_1)