nis/nis_lookup.c

   1 /* Copyright (C) 1997-1999, 2004, 2005, 2006, 2007
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Thorsten Kukuk <kukuk@uni-paderborn.de>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <string.h>
  22 #include <rpcsvc/nis.h>
  23 #include "nis_xdr.h"
  24 #include "nis_intern.h"
  25 #include <libnsl.h>
  26
  27
  28 nis_result *
  29 nis_lookup (const_nis_name name, const unsigned int flags)
  30 {
  31   nis_result *res = calloc (1, sizeof (nis_result));
  32   struct ns_request req;
  33   nis_name *names;
  34   nis_error status;
  35   int link_first_try = 0;
  36   int count_links = 0;   /* We will follow only 16 links in the deep */
  37   int done = 0;
  38   int name_nr = 0;
  39   nis_name namebuf[2] = {NULL, NULL};
  40
  41   if (res == NULL)
  42     return NULL;
  43
  44   if ((flags & EXPAND_NAME) && (name[strlen (name) - 1] != '.'))
  45     {
  46       names = nis_getnames (name);
  47       if (names == NULL)
  48         {
  49           NIS_RES_STATUS (res) = NIS_NAMEUNREACHABLE;
  50           return res;
  51         }
  52     }
  53   else
  54     {
  55       names = namebuf;
  56       names[0] = (nis_name)name;
  57     }
  58
  59   req.ns_name = names[0];
  60   while (!done)
  61     {
  62       dir_binding bptr;
  63       directory_obj *dir = NULL;
  64       req.ns_object.ns_object_len = 0;
  65       req.ns_object.ns_object_val = NULL;
  66
  67       status = __prepare_niscall (req.ns_name, &dir, &bptr, flags);
  68       if (__builtin_expect (status != NIS_SUCCESS, 0))
  69         {
  70           NIS_RES_STATUS (res) = status;
  71           goto out;
  72         }
  73
  74       do
  75         {
  76           static const struct timeval RPCTIMEOUT = {10, 0};
  77           enum clnt_stat result;
  78           char ndomain[strlen (req.ns_name) + 1];
  79
  80         again:
  81           result = clnt_call (bptr.clnt, NIS_LOOKUP,
  82                               (xdrproc_t) _xdr_ns_request,
  83                               (caddr_t) &req, (xdrproc_t) _xdr_nis_result,
  84                               (caddr_t) res, RPCTIMEOUT);
  85
  86           if (result != RPC_SUCCESS)
  87             status = NIS_RPCERROR;
  88           else
  89             {
  90               status = NIS_SUCCESS;
  91
  92               if (NIS_RES_STATUS (res) == NIS_SUCCESS)
  93                 {
  94                     if (__type_of (NIS_RES_OBJECT (res)) == NIS_LINK_OBJ
  95                         && (flags & FOLLOW_LINKS)) /* We are following links */
  96                       {
  97                         /* if we hit the link limit, bail */
  98                         if (count_links > NIS_MAXLINKS)
  99                           {
 100                             NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;
 101                             break;
 102                           }
 103                         ++count_links;
 104                         req.ns_name =
 105                           strdupa (NIS_RES_OBJECT (res)->LI_data.li_name);
 106
 107                         /* The following is a non-obvious optimization.  A
 108                            nis_freeresult call would call xdr_free as the
 109                            following code.  But it also would unnecessarily
 110                            free the result structure.  We avoid this here
 111                            along with the necessary tests.  */
 112                         xdr_free ((xdrproc_t) _xdr_nis_result, (char *) res);
 113                         memset (res, '\0', sizeof (*res));
 114
 115                         link_first_try = 1; /* Try at first the old binding */
 116                         goto again;
 117                       }
 118                 }
 119               else
 120                 if (NIS_RES_STATUS (res) == NIS_SYSTEMERROR
 121                     || NIS_RES_STATUS (res) == NIS_NOSUCHNAME
 122                     || NIS_RES_STATUS (res) == NIS_NOT_ME)
 123                   {
 124                     if (link_first_try)
 125                       {
 126                         __nisbind_destroy (&bptr);
 127                         nis_free_directory (dir);
 128                         /* Otherwise __nisfind_server will not do anything.  */
 129                         dir = NULL;
 130
 131                         if (__nisfind_server (req.ns_name, 1, &dir, &bptr,
 132                                               flags & ~MASTER_ONLY)
 133                             != NIS_SUCCESS)
 134                           goto out;
 135                       }
 136                     else
 137                       if (__nisbind_next (&bptr) != NIS_SUCCESS)
 138                         {
 139                           /* No more servers to search.  Try parent.  */
 140                           nis_domain_of_r (req.ns_name, ndomain,
 141                                            sizeof (ndomain));
 142                           req.ns_name = strdupa (ndomain);
 143                           if (strcmp (ndomain, ".") == 0)
 144                             {
 145                               NIS_RES_STATUS (res) = NIS_NAMEUNREACHABLE;
 146                               goto out;
 147                             }
 148
 149                           __nisbind_destroy (&bptr);
 150                           nis_free_directory (dir);
 151                           dir = NULL;
 152                           status = __prepare_niscall (req.ns_name, &dir,
 153                                                       &bptr, flags);
 154                           if (__builtin_expect (status != NIS_SUCCESS, 0))
 155                             {
 156                               NIS_RES_STATUS (res) = status;
 157                               goto out;
 158                             }
 159                           goto again;
 160                         }
 161
 162                     while (__nisbind_connect (&bptr) != NIS_SUCCESS)
 163                       {
 164                         if (__nisbind_next (&bptr) != NIS_SUCCESS)
 165                           {
 166                             nis_free_directory (dir);
 167                             goto out;
 168                           }
 169                       }
 170                     goto again;
 171                   }
 172               break;
 173             }
 174           link_first_try = 0; /* Set it back */
 175         }
 176       while ((flags & HARD_LOOKUP) && status == NIS_RPCERROR);
 177
 178       __nisbind_destroy (&bptr);
 179       nis_free_directory (dir);
 180
 181       if (status != NIS_SUCCESS)
 182         {
 183           NIS_RES_STATUS (res) = status;
 184           goto out;
 185         }
 186
 187       switch (NIS_RES_STATUS (res))
 188         {
 189         case NIS_PARTIAL:
 190         case NIS_SUCCESS:
 191         case NIS_S_SUCCESS:
 192         case NIS_LINKNAMEERROR: /* We follow to max links */
 193         case NIS_UNAVAIL: /* NIS+ is not installed, or all servers are down */
 194           ++done;
 195           break;
 196         default:
 197           /* Try the next domainname if we don't follow a link */
 198           if (count_links)
 199             {
 200               free (req.ns_name);
 201               NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;
 202               ++done;
 203               break;
 204             }
 205           ++name_nr;
 206           if (names[name_nr] == NULL)
 207             {
 208               ++done;
 209               break;
 210             }
 211           req.ns_name = names[name_nr];
 212           break;
 213         }
 214     }
 215
 216  out:
 217   if (names != namebuf)
 218     nis_freenames (names);
 219
 220   return res;
 221 }
 222 libnsl_hidden_def (nis_lookup)