1/* Copyright (C) 1997-2021 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, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <string.h>
20#include <rpcsvc/nis.h>
21#include "nis_xdr.h"
22#include "nis_intern.h"
23#include <libnsl.h>
24#include <shlib-compat.h>
25
26
27nis_result *
28nis_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 (__glibc_unlikely (status != NIS_SUCCESS))
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
78 again:
79 result = clnt_call (bptr.clnt, NIS_LOOKUP,
80 (xdrproc_t) _xdr_ns_request,
81 (caddr_t) &req, (xdrproc_t) _xdr_nis_result,
82 (caddr_t) res, RPCTIMEOUT);
83
84 if (result != RPC_SUCCESS)
85 status = NIS_RPCERROR;
86 else
87 {
88 status = NIS_SUCCESS;
89
90 if (NIS_RES_STATUS (res) == NIS_SUCCESS)
91 {
92 if (__type_of (NIS_RES_OBJECT (res)) == NIS_LINK_OBJ
93 && (flags & FOLLOW_LINKS)) /* We are following links */
94 {
95 /* if we hit the link limit, bail */
96 if (count_links > NIS_MAXLINKS)
97 {
98 NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;
99 break;
100 }
101 ++count_links;
102 req.ns_name =
103 strdupa (NIS_RES_OBJECT (res)->LI_data.li_name);
104
105 /* The following is a non-obvious optimization. A
106 nis_freeresult call would call xdr_free as the
107 following code. But it also would unnecessarily
108 free the result structure. We avoid this here
109 along with the necessary tests. */
110 xdr_free ((xdrproc_t) _xdr_nis_result, (char *) res);
111 memset (res, '\0', sizeof (*res));
112
113 link_first_try = 1; /* Try at first the old binding */
114 goto again;
115 }
116 }
117 else
118 if (NIS_RES_STATUS (res) == NIS_SYSTEMERROR
119 || NIS_RES_STATUS (res) == NIS_NOSUCHNAME
120 || NIS_RES_STATUS (res) == NIS_NOT_ME)
121 {
122 if (link_first_try)
123 {
124 __nisbind_destroy (&bptr);
125 nis_free_directory (dir);
126 /* Otherwise __nisfind_server will not do anything. */
127 dir = NULL;
128
129 if (__nisfind_server (req.ns_name, 1, &dir, &bptr,
130 flags & ~MASTER_ONLY)
131 != NIS_SUCCESS)
132 goto out;
133 }
134 else
135 if (__nisbind_next (&bptr) != NIS_SUCCESS)
136 {
137 /* No more servers to search. Try parent. */
138 const char *ndomain = __nis_domain_of (req.ns_name);
139 req.ns_name = strdupa (ndomain);
140 if (strcmp (req.ns_name, ".") == 0)
141 {
142 NIS_RES_STATUS (res) = NIS_NAMEUNREACHABLE;
143 goto out;
144 }
145
146 __nisbind_destroy (&bptr);
147 nis_free_directory (dir);
148 dir = NULL;
149 status = __prepare_niscall (req.ns_name, &dir,
150 &bptr, flags);
151 if (__glibc_unlikely (status != NIS_SUCCESS))
152 {
153 NIS_RES_STATUS (res) = status;
154 goto out;
155 }
156 goto again;
157 }
158
159 while (__nisbind_connect (&bptr) != NIS_SUCCESS)
160 {
161 if (__nisbind_next (&bptr) != NIS_SUCCESS)
162 {
163 nis_free_directory (dir);
164 goto out;
165 }
166 }
167 goto again;
168 }
169 break;
170 }
171 link_first_try = 0; /* Set it back */
172 }
173 while ((flags & HARD_LOOKUP) && status == NIS_RPCERROR);
174
175 __nisbind_destroy (&bptr);
176 nis_free_directory (dir);
177
178 if (status != NIS_SUCCESS)
179 {
180 NIS_RES_STATUS (res) = status;
181 goto out;
182 }
183
184 switch (NIS_RES_STATUS (res))
185 {
186 case NIS_PARTIAL:
187 case NIS_SUCCESS:
188 case NIS_S_SUCCESS:
189 case NIS_LINKNAMEERROR: /* We follow to max links */
190 case NIS_UNAVAIL: /* NIS+ is not installed, or all servers are down */
191 ++done;
192 break;
193 default:
194 /* Try the next domainname if we don't follow a link */
195 if (count_links)
196 {
197 free (req.ns_name);
198 NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;
199 ++done;
200 break;
201 }
202 ++name_nr;
203 if (names[name_nr] == NULL)
204 {
205 ++done;
206 break;
207 }
208 req.ns_name = names[name_nr];
209 break;
210 }
211 }
212
213 out:
214 if (names != namebuf)
215 nis_freenames (names);
216
217 return res;
218}
219libnsl_hidden_nolink_def (nis_lookup, GLIBC_2_1)
220