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bfff8b1b | 1 | /* Copyright (C) 2004-2017 Free Software Foundation, Inc. |
d19687d6 UD |
2 | This file is part of the GNU C Library. |
3 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2004. | |
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 | |
59ba27a6 PE |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
d19687d6 UD |
18 | |
19 | #include <assert.h> | |
20 | #include <errno.h> | |
21 | #include <netdb.h> | |
22 | #include <stdlib.h> | |
23 | #include <string.h> | |
24 | #include <unistd.h> | |
d19687d6 UD |
25 | #include <not-cancel.h> |
26 | ||
27 | #include "nscd-client.h" | |
62417d7e | 28 | #include "nscd_proto.h" |
d19687d6 UD |
29 | |
30 | ||
31 | /* Define in nscd_gethst_r.c. */ | |
32 | extern int __nss_not_use_nscd_hosts; | |
33 | ||
34 | ||
ed2ced8a | 35 | /* We use the mapping from nscd_gethst. */ |
6f8a7dff | 36 | libc_locked_map_ptr (extern, __hst_map_handle) attribute_hidden; |
d19687d6 | 37 | |
50e481ce UD |
38 | /* Defined in nscd_gethst_r.c. */ |
39 | extern int __nss_have_localdomain attribute_hidden; | |
40 | ||
d19687d6 UD |
41 | |
42 | int | |
43 | __nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop) | |
44 | { | |
a1ffb40e | 45 | if (__glibc_unlikely (__nss_have_localdomain >= 0)) |
50e481ce UD |
46 | { |
47 | if (__nss_have_localdomain == 0) | |
48 | __nss_have_localdomain = getenv ("LOCALDOMAIN") != NULL ? 1 : -1; | |
49 | if (__nss_have_localdomain > 0) | |
50 | { | |
51 | __nss_not_use_nscd_hosts = 1; | |
52 | return -1; | |
53 | } | |
54 | } | |
55 | ||
d19687d6 | 56 | size_t keylen = strlen (key) + 1; |
0891f970 | 57 | int gc_cycle; |
1a77d37f | 58 | int nretries = 0; |
0891f970 UD |
59 | |
60 | /* If the mapping is available, try to search there instead of | |
61 | communicating with the nscd. */ | |
62 | struct mapped_database *mapped; | |
ed2ced8a UD |
63 | mapped = __nscd_get_map_ref (GETFDHST, "hosts", &__hst_map_handle, |
64 | &gc_cycle); | |
0891f970 UD |
65 | |
66 | retry:; | |
d19687d6 UD |
67 | struct nscd_ai_result *resultbuf = NULL; |
68 | const char *recend = (const char *) ~UINTMAX_C (0); | |
69 | char *respdata = NULL; | |
70 | int retval = -1; | |
71 | int sock = -1; | |
1a77d37f | 72 | ai_response_header ai_resp; |
d19687d6 | 73 | |
81177191 | 74 | if (mapped != NO_MAPPING) |
d19687d6 | 75 | { |
1a77d37f | 76 | struct datahead *found = __nscd_cache_search (GETAI, key, keylen, |
cfe1fc10 | 77 | mapped, sizeof ai_resp); |
d19687d6 UD |
78 | if (found != NULL) |
79 | { | |
1a77d37f JJ |
80 | respdata = (char *) (&found->data[0].aidata + 1); |
81 | ai_resp = found->data[0].aidata; | |
d19687d6 | 82 | recend = (const char *) found->data + found->recsize; |
1a77d37f JJ |
83 | /* Now check if we can trust ai_resp fields. If GC is |
84 | in progress, it can contain anything. */ | |
85 | if (mapped->head->gc_cycle != gc_cycle) | |
86 | { | |
87 | retval = -2; | |
88 | goto out; | |
89 | } | |
d19687d6 UD |
90 | } |
91 | } | |
92 | ||
93 | /* If we do not have the cache mapped, try to get the data over the | |
94 | socket. */ | |
1a77d37f | 95 | if (respdata == NULL) |
d19687d6 | 96 | { |
1a77d37f JJ |
97 | sock = __nscd_open_socket (key, keylen, GETAI, &ai_resp, |
98 | sizeof (ai_resp)); | |
d19687d6 UD |
99 | if (sock == -1) |
100 | { | |
6aa10807 | 101 | /* nscd not running or wrong version. */ |
d19687d6 | 102 | __nss_not_use_nscd_hosts = 1; |
81177191 | 103 | goto out; |
d19687d6 | 104 | } |
d19687d6 UD |
105 | } |
106 | ||
1a77d37f | 107 | if (ai_resp.found == 1) |
d19687d6 | 108 | { |
1a77d37f | 109 | size_t datalen = ai_resp.naddrs + ai_resp.addrslen + ai_resp.canonlen; |
d19687d6 | 110 | |
1a77d37f | 111 | /* This check really only affects the case where the data |
d19687d6 | 112 | comes from the mapped cache. */ |
1a77d37f | 113 | if (respdata + datalen > recend) |
d19687d6 UD |
114 | { |
115 | assert (sock == -1); | |
116 | goto out; | |
117 | } | |
118 | ||
119 | /* Create result. */ | |
120 | resultbuf = (struct nscd_ai_result *) malloc (sizeof (*resultbuf) | |
121 | + datalen); | |
122 | if (resultbuf == NULL) | |
123 | { | |
124 | *h_errnop = NETDB_INTERNAL; | |
8dd71997 | 125 | goto out_close; |
d19687d6 UD |
126 | } |
127 | ||
128 | /* Set up the data structure, including pointers. */ | |
1a77d37f | 129 | resultbuf->naddrs = ai_resp.naddrs; |
d19687d6 | 130 | resultbuf->addrs = (char *) (resultbuf + 1); |
1a77d37f JJ |
131 | resultbuf->family = (uint8_t *) (resultbuf->addrs + ai_resp.addrslen); |
132 | if (ai_resp.canonlen != 0) | |
d19687d6 UD |
133 | resultbuf->canon = (char *) (resultbuf->family + resultbuf->naddrs); |
134 | else | |
135 | resultbuf->canon = NULL; | |
136 | ||
137 | if (respdata == NULL) | |
138 | { | |
139 | /* Read the data from the socket. */ | |
d2dc7d84 | 140 | if ((size_t) __readall (sock, resultbuf + 1, datalen) == datalen) |
d19687d6 UD |
141 | { |
142 | retval = 0; | |
143 | *result = resultbuf; | |
144 | } | |
0891f970 UD |
145 | else |
146 | { | |
147 | free (resultbuf); | |
148 | *h_errnop = NETDB_INTERNAL; | |
149 | } | |
d19687d6 UD |
150 | } |
151 | else | |
152 | { | |
153 | /* Copy the data in the block. */ | |
154 | memcpy (resultbuf + 1, respdata, datalen); | |
155 | ||
5429ff76 UD |
156 | /* Try to detect corrupt databases. */ |
157 | if (resultbuf->canon != NULL | |
1a77d37f | 158 | && resultbuf->canon[ai_resp.canonlen - 1] != '\0') |
5429ff76 | 159 | /* We cannot use the database. */ |
8dd71997 | 160 | { |
1a77d37f JJ |
161 | if (mapped->head->gc_cycle != gc_cycle) |
162 | retval = -2; | |
163 | else | |
164 | free (resultbuf); | |
8dd71997 UD |
165 | goto out_close; |
166 | } | |
5429ff76 | 167 | |
d19687d6 UD |
168 | retval = 0; |
169 | *result = resultbuf; | |
170 | } | |
171 | } | |
172 | else | |
173 | { | |
a1ffb40e | 174 | if (__glibc_unlikely (ai_resp.found == -1)) |
6aa10807 UD |
175 | { |
176 | /* The daemon does not cache this database. */ | |
177 | __nss_not_use_nscd_hosts = 1; | |
178 | goto out_close; | |
179 | } | |
180 | ||
d19687d6 | 181 | /* Store the error number. */ |
1a77d37f | 182 | *h_errnop = ai_resp.error; |
d19687d6 | 183 | |
cfca0aa3 UD |
184 | /* Set errno to 0 to indicate no error, just no found record. */ |
185 | __set_errno (0); | |
d19687d6 UD |
186 | /* Even though we have not found anything, the result is zero. */ |
187 | retval = 0; | |
188 | } | |
189 | ||
5429ff76 | 190 | out_close: |
d19687d6 UD |
191 | if (sock != -1) |
192 | close_not_cancel_no_status (sock); | |
193 | out: | |
1a77d37f | 194 | if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0) |
0891f970 UD |
195 | { |
196 | /* When we come here this means there has been a GC cycle while we | |
197 | were looking for the data. This means the data might have been | |
198 | inconsistent. Retry if possible. */ | |
1a77d37f | 199 | if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1) |
0891f970 UD |
200 | { |
201 | /* nscd is just running gc now. Disable using the mapping. */ | |
1a77d37f JJ |
202 | if (atomic_decrement_val (&mapped->counter) == 0) |
203 | __nscd_unmap (mapped); | |
0891f970 UD |
204 | mapped = NO_MAPPING; |
205 | } | |
206 | ||
1a77d37f JJ |
207 | if (retval != -1) |
208 | { | |
209 | *result = NULL; | |
210 | free (resultbuf); | |
211 | goto retry; | |
212 | } | |
0891f970 | 213 | } |
d19687d6 UD |
214 | |
215 | return retval; | |
216 | } |