aboutsummaryrefslogtreecommitdiff
path: root/nis/nis_lookup.c
blob: 7f8226c9e7069315f72bb1540b9156f2a90c1a71 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
/* Copyright (C) 1997-2019 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
   <https://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)