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
  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, &bptr,
 131                                               flags & ~MASTER_ONLY)
 132                             != NIS_SUCCESS)
 133                           goto out;
 134                       }
 135                     else
 136                       if (__nisbind_next (&bptr) != NIS_SUCCESS)
 137                         {
 138                           /* No more servers to search.  Try parent.  */
 139                           const char *ndomain = __nis_domain_of (req.ns_name);
 140                           req.ns_name = strdupa (ndomain);
 141                           if (strcmp (req.ns_name, ".") == 0)
 142                             {
 143                               NIS_RES_STATUS (res) = NIS_NAMEUNREACHABLE;
 144                               goto out;
 145                             }
 146
 147                           __nisbind_destroy (&bptr);
 148                           nis_free_directory (dir);
 149                           dir = NULL;
 150                           status = __prepare_niscall (req.ns_name, &dir,
 151                                                       &bptr, flags);
 152                           if (__builtin_expect (status != NIS_SUCCESS, 0))
 153                             {
 154                               NIS_RES_STATUS (res) = status;
 155                               goto out;
 156                             }
 157                           goto again;
 158                         }
 159
 160                     while (__nisbind_connect (&bptr) != NIS_SUCCESS)
 161                       {
 162                         if (__nisbind_next (&bptr) != NIS_SUCCESS)
 163                           {
 164                             nis_free_directory (dir);
 165                             goto out;
 166                           }
 167                       }
 168                     goto again;
 169                   }
 170               break;
 171             }
 172           link_first_try = 0; /* Set it back */
 173         }
 174       while ((flags & HARD_LOOKUP) && status == NIS_RPCERROR);
 175
 176       __nisbind_destroy (&bptr);
 177       nis_free_directory (dir);
 178
 179       if (status != NIS_SUCCESS)
 180         {
 181           NIS_RES_STATUS (res) = status;
 182           goto out;
 183         }
 184
 185       switch (NIS_RES_STATUS (res))
 186         {
 187         case NIS_PARTIAL:
 188         case NIS_SUCCESS:
 189         case NIS_S_SUCCESS:
 190         case NIS_LINKNAMEERROR: /* We follow to max links */
 191         case NIS_UNAVAIL: /* NIS+ is not installed, or all servers are down */
 192           ++done;
 193           break;
 194         default:
 195           /* Try the next domainname if we don't follow a link */
 196           if (count_links)
 197             {
 198               free (req.ns_name);
 199               NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;
 200               ++done;
 201               break;
 202             }
 203           ++name_nr;
 204           if (names[name_nr] == NULL)
 205             {
 206               ++done;
 207               break;
 208             }
 209           req.ns_name = names[name_nr];
 210           break;
 211         }
 212     }
 213
 214  out:
 215   if (names != namebuf)
 216     nis_freenames (names);
 217
 218   return res;
 219 }
 220 libnsl_hidden_def (nis_lookup)