1 /* Copyright (C) 1997-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18 #include <string.h>
19 #include <rpcsvc/nis.h>
20 #include "nis_xdr.h"
21 #include "nis_intern.h"
22 #include <libnsl.h>
23 #include <shlib-compat.h>
24
25
26 nis_result *
27 nis_lookup (const_nis_name name, const unsigned int flags)
28 {
29 nis_result *res = calloc (1, sizeof (nis_result));
30 struct ns_request req;
31 nis_name *names;
32 nis_error status;
33 int link_first_try = 0;
34 int count_links = 0; /* We will follow only 16 links in the deep */
35 int done = 0;
36 int name_nr = 0;
37 nis_name namebuf[2] = {NULL, NULL};
38
39 if (res == NULL)
40 return NULL;
41
42 if ((flags & EXPAND_NAME) && (name[strlen (name) - 1] != '.'))
43 {
44 names = nis_getnames (name);
45 if (names == NULL)
46 {
47 NIS_RES_STATUS (res) = NIS_NAMEUNREACHABLE;
48 return res;
49 }
50 }
51 else
52 {
53 names = namebuf;
54 names[0] = (nis_name)name;
55 }
56
57 req.ns_name = names[0];
58 while (!done)
59 {
60 dir_binding bptr;
61 directory_obj *dir = NULL;
62 req.ns_object.ns_object_len = 0;
63 req.ns_object.ns_object_val = NULL;
64
65 status = __prepare_niscall (req.ns_name, &dir, &bptr, flags);
66 if (__glibc_unlikely (status != NIS_SUCCESS))
67 {
68 NIS_RES_STATUS (res) = status;
69 goto out;
70 }
71
72 do
73 {
74 static const struct timeval RPCTIMEOUT = {10, 0};
75 enum clnt_stat result;
76
77 again:
78 result = clnt_call (bptr.clnt, NIS_LOOKUP,
79 (xdrproc_t) _xdr_ns_request,
80 (caddr_t) &req, (xdrproc_t) _xdr_nis_result,
81 (caddr_t) res, RPCTIMEOUT);
82
83 if (result != RPC_SUCCESS)
84 status = NIS_RPCERROR;
85 else
86 {
87 status = NIS_SUCCESS;
88
89 if (NIS_RES_STATUS (res) == NIS_SUCCESS)
90 {
91 if (__type_of (NIS_RES_OBJECT (res)) == NIS_LINK_OBJ
92 && (flags & FOLLOW_LINKS)) /* We are following links */
93 {
94 /* if we hit the link limit, bail */
95 if (count_links > NIS_MAXLINKS)
96 {
97 NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;
98 break;
99 }
100 ++count_links;
101 req.ns_name =
102 strdupa (NIS_RES_OBJECT (res)->LI_data.li_name);
103
104 /* The following is a non-obvious optimization. A
105 nis_freeresult call would call xdr_free as the
106 following code. But it also would unnecessarily
107 free the result structure. We avoid this here
108 along with the necessary tests. */
109 xdr_free ((xdrproc_t) _xdr_nis_result, (char *) res);
110 memset (res, '\0', sizeof (*res));
111
112 link_first_try = 1; /* Try at first the old binding */
113 goto again;
114 }
115 }
116 else
117 if (NIS_RES_STATUS (res) == NIS_SYSTEMERROR
118 || NIS_RES_STATUS (res) == NIS_NOSUCHNAME
119 || NIS_RES_STATUS (res) == NIS_NOT_ME)
120 {
121 if (link_first_try)
122 {
123 __nisbind_destroy (&bptr);
124 nis_free_directory (dir);
125 /* Otherwise __nisfind_server will not do anything. */
126 dir = NULL;
127
128 if (__nisfind_server (req.ns_name, 1, &dir, &bptr,
129 flags & ~MASTER_ONLY)
130 != NIS_SUCCESS)
131 goto out;
132 }
133 else
134 if (__nisbind_next (&bptr) != NIS_SUCCESS)
135 {
136 /* No more servers to search. Try parent. */
137 const char *ndomain = __nis_domain_of (req.ns_name);
138 req.ns_name = strdupa (ndomain);
139 if (strcmp (req.ns_name, ".") == 0)
140 {
141 NIS_RES_STATUS (res) = NIS_NAMEUNREACHABLE;
142 goto out;
143 }
144
145 __nisbind_destroy (&bptr);
146 nis_free_directory (dir);
147 dir = NULL;
148 status = __prepare_niscall (req.ns_name, &dir,
149 &bptr, flags);
150 if (__glibc_unlikely (status != NIS_SUCCESS))
151 {
152 NIS_RES_STATUS (res) = status;
153 goto out;
154 }
155 goto again;
156 }
157
158 while (__nisbind_connect (&bptr) != NIS_SUCCESS)
159 {
160 if (__nisbind_next (&bptr) != NIS_SUCCESS)
161 {
162 nis_free_directory (dir);
163 goto out;
164 }
165 }
166 goto again;
167 }
168 break;
169 }
170 link_first_try = 0; /* Set it back */
171 }
172 while ((flags & HARD_LOOKUP) && status == NIS_RPCERROR);
173
174 __nisbind_destroy (&bptr);
175 nis_free_directory (dir);
176
177 if (status != NIS_SUCCESS)
178 {
179 NIS_RES_STATUS (res) = status;
180 goto out;
181 }
182
183 switch (NIS_RES_STATUS (res))
184 {
185 case NIS_PARTIAL:
186 case NIS_SUCCESS:
187 case NIS_S_SUCCESS:
188 case NIS_LINKNAMEERROR: /* We follow to max links */
189 case NIS_UNAVAIL: /* NIS+ is not installed, or all servers are down */
190 ++done;
191 break;
192 default:
193 /* Try the next domainname if we don't follow a link */
194 if (count_links)
195 {
196 free (req.ns_name);
197 NIS_RES_STATUS (res) = NIS_LINKNAMEERROR;
198 ++done;
199 break;
200 }
201 ++name_nr;
202 if (names[name_nr] == NULL)
203 {
204 ++done;
205 break;
206 }
207 req.ns_name = names[name_nr];
208 break;
209 }
210 }
211
212 out:
213 if (names != namebuf)
214 nis_freenames (names);
215
216 return res;
217 }
218 libnsl_hidden_nolink_def (nis_lookup, GLIBC_2_1)