nis/nis_lookup.c

   1 /* Copyright (C) 1997-1999, 2004, 2005, 2006 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@uni-paderborn.de>, 1997.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <string.h>
  21 #include <rpcsvc/nis.h>
  22 #include "nis_xdr.h"
  23 #include "nis_intern.h"
  24 #include <libnsl.h>
  25
  26
  27 nis_result *
  28 nis_lookup (const_nis_name name, const unsigned int flags)
  29 {
  30   nis_result *res = calloc (1, sizeof (nis_result));
  31   struct ns_request req;
  32   nis_name *names;
  33   nis_error status;
  34   int link_first_try = 0;
  35   int count_links = 0;   /* We will follow only 16 links in the deep */
  36   int done = 0;
  37   int name_nr = 0;
  38   nis_name namebuf[2] = {NULL, NULL};
  39
  40   if (res == NULL)
  41     return NULL;
  42
  43   if ((flags & EXPAND_NAME) && (name[strlen (name) - 1] != '.'))
  44     {
  45       names = nis_getnames (name);
  46       if (names == NULL)
  47         {
  48           NIS_RES_STATUS (res) = NIS_NAMEUNREACHABLE;
  49           return res;
  50         }
  51     }
  52   else
  53     {
  54       names = namebuf;
  55       names[0] = (nis_name)name;
  56     }
  57
  58   req.ns_name = names[0];
  59   while (!done)
  60     {
  61       dir_binding bptr;
  62       directory_obj *dir = NULL;
  63       req.ns_object.ns_object_len = 0;
  64       req.ns_object.ns_object_val = NULL;
  65
  66       status = __prepare_niscall (req.ns_name, &dir, &bptr, flags);
  67       if (__builtin_expect (status != NIS_SUCCESS, 0))
  68         {
  69           NIS_RES_STATUS (res) = status;
  70           goto out;
  71         }
  72
  73       do
  74         {
  75           static const struct timeval RPCTIMEOUT = {10, 0};
  76           enum clnt_stat result;
  77           char ndomain[strlen (req.ns_name) + 1];
  78
  79         again:
  80           result = clnt_call (bptr.clnt, NIS_LOOKUP,
  81                               (xdrproc_t) _xdr_ns_request,
  82                               (caddr_t) &req, (xdrproc_t) _xdr_nis_result,
  83                               (caddr_t) res, RPCTIMEOUT);
  84
  85           if (result != RPC_SUCCESS)
  86             status = NIS_RPCERROR;
  87           else
  88             {
  89               status = NIS_SUCCESS;
  90
  91               if (NIS_RES_STATUS (res) == NIS_SUCCESS)
  92                 {
  93                     if (__type_of (NIS_RES_OBJECT (res)) == NIS_LINK_OBJ
  94                         && (flags & FOLLOW_LINKS)) /* We are following links */
  95                       {
  96                         /* if we hit the link limit, bail */
  97                         if (count_links > NIS_MAXLINKS)
  98                           {
  99                             NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;
 100                             break;
 101                           }
 102                         ++count_links;
 103                         req.ns_name =
 104                           strdupa (NIS_RES_OBJECT (res)->LI_data.li_name);
 105
 106                         /* The following is a non-obvious optimization.  A
 107                            nis_freeresult call would call xdr_free as the
 108                            following code.  But it also would unnecessarily
 109                            free the result structure.  We avoid this here
 110                            along with the necessary tests.  */
 111                         xdr_free ((xdrproc_t) _xdr_nis_result, (char *) res);
 112                         memset (res, '\0', sizeof (*res));
 113
 114                         link_first_try = 1; /* Try at first the old binding */
 115                         goto again;
 116                       }
 117                 }
 118               else
 119                 if (NIS_RES_STATUS (res) == NIS_SYSTEMERROR
 120                     || NIS_RES_STATUS (res) == NIS_NOSUCHNAME
 121                     || NIS_RES_STATUS (res) == NIS_NOT_ME)
 122                   {
 123                     if (link_first_try)
 124                       {
 125                         __nisbind_destroy (&bptr);
 126                         nis_free_directory (dir);
 127                         /* Otherwise __nisfind_server will not do anything.  */
 128                         dir = NULL;
 129
 130                         if (__nisfind_server (req.ns_name, 1, &dir)
 131                             != NIS_SUCCESS)
 132                           goto out;
 133
 134                         if (__nisbind_create (&bptr,
 135                                               dir->do_servers.do_servers_val,
 136                                               dir->do_servers.do_servers_len,
 137                                               flags) != NIS_SUCCESS)
 138                           {
 139                             nis_free_directory (dir);
 140                             goto out;
 141                           }
 142                       }
 143                     else
 144                       if (__nisbind_next (&bptr) != NIS_SUCCESS)
 145                         {
 146                           /* No more servers to search.  Try parent.  */
 147                           nis_domain_of_r (req.ns_name, ndomain,
 148                                            sizeof (ndomain));
 149                           req.ns_name = strdupa (ndomain);
 150                           if (strcmp (ndomain, ".") == 0)
 151                             {
 152                               NIS_RES_STATUS (res) = NIS_NAMEUNREACHABLE;
 153                               goto out;
 154                             }
 155
 156                           __nisbind_destroy (&bptr);
 157                           nis_free_directory (dir);
 158                           dir = NULL;
 159                           status = __prepare_niscall (req.ns_name, &dir,
 160                                                       &bptr, flags);
 161                           if (__builtin_expect (status != NIS_SUCCESS, 0))
 162                             {
 163                               NIS_RES_STATUS (res) = status;
 164                               goto out;
 165                             }
 166                           goto again;
 167                         }
 168
 169                     while (__nisbind_connect (&bptr) != NIS_SUCCESS)
 170                       {
 171                         if (__nisbind_next (&bptr) != NIS_SUCCESS)
 172                           {
 173                             nis_free_directory (dir);
 174                             goto out;
 175                           }
 176                       }
 177                     goto again;
 178                   }
 179               break;
 180             }
 181           link_first_try = 0; /* Set it back */
 182         }
 183       while ((flags & HARD_LOOKUP) && status == NIS_RPCERROR);
 184
 185       __nisbind_destroy (&bptr);
 186       nis_free_directory (dir);
 187
 188       if (status != NIS_SUCCESS)
 189         {
 190           NIS_RES_STATUS (res) = status;
 191           goto out;
 192         }
 193
 194       switch (NIS_RES_STATUS (res))
 195         {
 196         case NIS_PARTIAL:
 197         case NIS_SUCCESS:
 198         case NIS_S_SUCCESS:
 199         case NIS_LINKNAMEERROR: /* We follow to max links */
 200         case NIS_UNAVAIL: /* NIS+ is not installed, or all servers are down */
 201           ++done;
 202           break;
 203         default:
 204           /* Try the next domainname if we don't follow a link */
 205           if (count_links)
 206             {
 207               free (req.ns_name);
 208               NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;
 209               ++done;
 210               break;
 211             }
 212           ++name_nr;
 213           if (names[name_nr] == NULL)
 214             {
 215               ++done;
 216               break;
 217             }
 218           req.ns_name = names[name_nr];
 219           break;
 220         }
 221     }
 222
 223  out:
 224   if (names != namebuf)
 225     nis_freenames (names);
 226
 227   return res;
 228 }
 229 libnsl_hidden_def (nis_lookup)