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
  25 nis_result *
  26 nis_lookup (const_nis_name name, const unsigned int flags)
  27 {
  28   nis_result *res = calloc (1, sizeof (nis_result));
  29   struct ns_request req;
  30   nis_name *names;
  31   nis_error status;
  32   int link_first_try = 0;
  33   int count_links = 0;   /* We will follow only 16 links in the deep */
  34   int done = 0;
  35   int name_nr = 0;
  36   nis_name namebuf[2] = {NULL, NULL};
  37
  38   if (res == NULL)
  39     return NULL;
  40
  41   if ((flags & EXPAND_NAME) && (name[strlen (name) - 1] != '.'))
  42     {
  43       names = nis_getnames (name);
  44       if (names == NULL)
  45         {
  46           NIS_RES_STATUS (res) = NIS_NAMEUNREACHABLE;
  47           return res;
  48         }
  49     }
  50   else
  51     {
  52       names = namebuf;
  53       names[0] = (nis_name)name;
  54     }
  55
  56   req.ns_name = names[0];
  57   while (!done)
  58     {
  59       dir_binding bptr;
  60       directory_obj *dir = NULL;
  61       req.ns_object.ns_object_len = 0;
  62       req.ns_object.ns_object_val = NULL;
  63
  64       status = __nisfind_server (req.ns_name, &dir);
  65       if (status != NIS_SUCCESS)
  66         {
  67           NIS_RES_STATUS (res) = status;
  68           goto out;
  69         }
  70
  71       status = __nisbind_create (&bptr, dir->do_servers.do_servers_val,
  72                                  dir->do_servers.do_servers_len, flags);
  73       if (status != NIS_SUCCESS)
  74         {
  75           NIS_RES_STATUS (res) = status;
  76           nis_free_directory (dir);
  77           goto out;;
  78         }
  79
  80       while (__nisbind_connect (&bptr) != NIS_SUCCESS)
  81         {
  82           if (__nisbind_next (&bptr) != NIS_SUCCESS)
  83             {
  84               nis_free_directory (dir);
  85               NIS_RES_STATUS (res) = NIS_NAMEUNREACHABLE;
  86               goto out;
  87             }
  88         }
  89
  90       do
  91         {
  92           static const struct timeval RPCTIMEOUT = {10, 0};
  93           enum clnt_stat result;
  94
  95         again:
  96           result = clnt_call (bptr.clnt, NIS_LOOKUP,
  97                               (xdrproc_t) _xdr_ns_request,
  98                               (caddr_t) &req, (xdrproc_t) _xdr_nis_result,
  99                               (caddr_t) res, RPCTIMEOUT);
 100
 101           if (result != RPC_SUCCESS)
 102             status = NIS_RPCERROR;
 103           else
 104             {
 105               status = NIS_SUCCESS;
 106
 107               if (NIS_RES_STATUS (res) == NIS_SUCCESS)
 108                 {
 109                     if (__type_of(NIS_RES_OBJECT (res)) == NIS_LINK_OBJ
 110                         && (flags & FOLLOW_LINKS)) /* We are following links */
 111                       {
 112                         if (count_links)
 113                           free (req.ns_name);
 114                         /* if we hit the link limit, bail */
 115                         if (count_links > NIS_MAXLINKS)
 116                           {
 117                             NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;
 118                             break;
 119                           }
 120                         ++count_links;
 121                         req.ns_name =
 122                           strdup (NIS_RES_OBJECT (res)->LI_data.li_name);
 123                         if (req.ns_name == NULL)
 124                           {
 125                             nis_free_directory (dir);
 126                             res = NULL;
 127                             goto out;
 128                           }
 129
 130                         /* The following is a non-obvious optimization.  A
 131                            nis_freeresult call would call xdr_free as the
 132                            following code.  But it also would unnecessarily
 133                            free the result structure.  We avoid this here
 134                            along with the necessary tests.  */
 135 #if 1
 136                         xdr_free ((xdrproc_t) _xdr_nis_result, (char *) res);
 137                         memset (res, '\0', sizeof (*res));
 138 #else
 139                         nis_freeresult (res);
 140                         res = calloc (1, sizeof (nis_result));
 141                         if (res == NULL)
 142                           {
 143                             __nisbind_destroy (&bptr);
 144                             return NULL;
 145                           }
 146 #endif
 147
 148                         link_first_try = 1; /* Try at first the old binding */
 149                         goto again;
 150                       }
 151                 }
 152               else
 153                 if (NIS_RES_STATUS (res) == NIS_SYSTEMERROR
 154                     || NIS_RES_STATUS (res) == NIS_NOSUCHNAME
 155                     || NIS_RES_STATUS (res) == NIS_NOT_ME)
 156                   {
 157                     if (link_first_try)
 158                       {
 159                         __nisbind_destroy (&bptr);
 160                         nis_free_directory (dir);
 161                         /* Otherwise __nisfind_server will not do anything.  */
 162                         dir = NULL;
 163
 164                         if (__nisfind_server (req.ns_name, &dir)
 165                             != NIS_SUCCESS)
 166                           goto out;
 167
 168                         if (__nisbind_create (&bptr,
 169                                               dir->do_servers.do_servers_val,
 170                                               dir->do_servers.do_servers_len,
 171                                               flags) != NIS_SUCCESS)
 172                           {
 173                             nis_free_directory (dir);
 174                             goto out;
 175                           }
 176                       }
 177                     else
 178                       if (__nisbind_next (&bptr) != NIS_SUCCESS)
 179                         break; /* No more servers to search */
 180
 181                     while (__nisbind_connect (&bptr) != NIS_SUCCESS)
 182                       {
 183                         if (__nisbind_next (&bptr) != NIS_SUCCESS)
 184                           {
 185                             nis_free_directory (dir);
 186                             goto out;
 187                           }
 188                       }
 189                     goto again;
 190                   }
 191               break;
 192             }
 193           link_first_try = 0; /* Set it back */
 194         }
 195       while ((flags & HARD_LOOKUP) && status == NIS_RPCERROR);
 196
 197       __nisbind_destroy (&bptr);
 198       nis_free_directory (dir);
 199
 200       if (status != NIS_SUCCESS)
 201         {
 202           NIS_RES_STATUS (res) = status;
 203           goto out;
 204         }
 205
 206       switch (NIS_RES_STATUS (res))
 207         {
 208         case NIS_PARTIAL:
 209         case NIS_SUCCESS:
 210         case NIS_S_SUCCESS:
 211         case NIS_LINKNAMEERROR: /* We follow to max links */
 212         case NIS_UNAVAIL: /* NIS+ is not installed, or all servers are down */
 213           ++done;
 214           break;
 215         default:
 216           /* Try the next domainname if we don't follow a link */
 217           if (count_links)
 218             {
 219               free (req.ns_name);
 220               NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;
 221               ++done;
 222               break;
 223             }
 224           ++name_nr;
 225           if (names[name_nr] == NULL)
 226             {
 227               ++done;
 228               break;
 229             }
 230           req.ns_name = names[name_nr];
 231           break;
 232         }
 233     }
 234
 235  out:
 236   if (names != namebuf)
 237     nis_freenames (names);
 238
 239   return res;
 240 }
 241 libnsl_hidden_def (nis_lookup)