1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28 #include <sys/cdefs.h>
29 #include <sys/types.h>
30 #include <arpa/inet.h>
31 #include "arpa_nameser.h"
32 #include <netdb.h>
33 #include "resolv_private.h"
34 #include "resolv_cache.h"
35 #include <pthread.h>
36 #include <stdlib.h>
37
38 #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
39 #include <sys/_system_properties.h>
40
41 static pthread_key_t _res_key;
42 static pthread_once_t _res_once;
43
44 typedef struct {
45 int _h_errno;
46 struct __res_state _nres[1];
47 unsigned _serial;
48 struct prop_info* _pi;
49 struct res_static _rstatic[1];
50 } _res_thread;
51
52 static _res_thread*
_res_thread_alloc(void)53 _res_thread_alloc(void)
54 {
55 _res_thread* rt = malloc(sizeof(*rt));
56
57 if (rt) {
58 rt->_h_errno = 0;
59 /* Special system property which tracks any changes to 'net.*'. */
60 rt->_serial = 0;
61 rt->_pi = (struct prop_info*) __system_property_find("net.change");
62 if (rt->_pi) {
63 rt->_serial = rt->_pi->serial;
64 }
65 if ( res_ninit( rt->_nres ) < 0 ) {
66 free(rt);
67 rt = NULL;
68 } else {
69 memset(rt->_rstatic, 0, sizeof rt->_rstatic);
70 }
71 }
72 return rt;
73 }
74
75 static void
_res_static_done(res_static rs)76 _res_static_done( res_static rs )
77 {
78 /* fortunately, there is nothing to do here, since the
79 * points in h_addr_ptrs and host_aliases should all
80 * point to 'hostbuf'
81 */
82 if (rs->hostf) { /* should not happen in theory, but just be safe */
83 fclose(rs->hostf);
84 rs->hostf = NULL;
85 }
86 free(rs->servent.s_aliases);
87 }
88
89 static void
_res_thread_free(void * _rt)90 _res_thread_free( void* _rt )
91 {
92 _res_thread* rt = _rt;
93
94 _res_static_done(rt->_rstatic);
95 res_ndestroy(rt->_nres);
96 free(rt);
97 }
98
99 static void
_res_init_key(void)100 _res_init_key( void )
101 {
102 pthread_key_create( &_res_key, _res_thread_free );
103 }
104
105 static _res_thread*
_res_thread_get(void)106 _res_thread_get(void)
107 {
108 _res_thread* rt;
109 pthread_once( &_res_once, _res_init_key );
110 rt = pthread_getspecific( _res_key );
111 if (rt == NULL) {
112 if ((rt = _res_thread_alloc()) == NULL) {
113 return NULL;
114 }
115 rt->_h_errno = 0;
116 rt->_serial = 0;
117 pthread_setspecific( _res_key, rt );
118 }
119 /* Check the serial value for any chanes to net.* properties. */
120 if (rt->_pi == NULL) {
121 rt->_pi = (struct prop_info*) __system_property_find("net.change");
122 }
123 if (rt->_pi == NULL || rt->_serial == rt->_pi->serial) {
124 return rt;
125 }
126 rt->_serial = rt->_pi->serial;
127 /* Reload from system properties. */
128 if ( res_ninit( rt->_nres ) < 0 ) {
129 free(rt);
130 rt = NULL;
131 pthread_setspecific( _res_key, rt );
132 }
133 _resolv_cache_reset(rt->_serial);
134 return rt;
135 }
136
137 struct __res_state _nres;
138
139 #if 0
140 struct resolv_cache*
141 __get_res_cache(void)
142 {
143 _res_thread* rt = _res_thread_get();
144
145 if (!rt)
146 return NULL;
147
148 if (!rt->_cache) {
149 rt->_cache = _resolv_cache_create();
150 }
151 return rt->_cache;
152 }
153 #endif
154
155 int*
__get_h_errno(void)156 __get_h_errno(void)
157 {
158 _res_thread* rt = _res_thread_get();
159 static int panic = NETDB_INTERNAL;
160
161 return rt ? &rt->_h_errno : &panic;
162 }
163
164 res_state
__res_get_state(void)165 __res_get_state(void)
166 {
167 _res_thread* rt = _res_thread_get();
168
169 return rt ? rt->_nres : NULL;
170 }
171
172 void
__res_put_state(res_state res)173 __res_put_state(res_state res)
174 {
175 /* nothing to do */
176 res=res;
177 }
178
179 res_static
__res_get_static(void)180 __res_get_static(void)
181 {
182 _res_thread* rt = _res_thread_get();
183
184 return rt ? rt->_rstatic : NULL;
185 }
186