1
2 /* Copyright 1998 by the Massachusetts Institute of Technology.
3 * Copyright (C) 2004-2009 by Daniel Stenberg
4 *
5 * Permission to use, copy, modify, and distribute this
6 * software and its documentation for any purpose and without
7 * fee is hereby granted, provided that the above copyright
8 * notice appear in all copies and that both that copyright
9 * notice and this permission notice appear in supporting
10 * documentation, and that the name of M.I.T. not be used in
11 * advertising or publicity pertaining to distribution of the
12 * software without specific, written prior permission.
13 * M.I.T. makes no representations about the suitability of
14 * this software for any purpose. It is provided "as is"
15 * without express or implied warranty.
16 */
17
18 #include "ares_setup.h"
19
20 #include "ares.h"
21 #include "ares_library_init.h"
22 #include "ares_private.h"
23
24 /* library-private global and unique instance vars */
25
26 #ifdef USE_WINSOCK
27 fpGetNetworkParams_t ares_fpGetNetworkParams = ZERO_NULL;
28 fpSystemFunction036_t ares_fpSystemFunction036 = ZERO_NULL;
29 fpGetAdaptersAddresses_t ares_fpGetAdaptersAddresses = ZERO_NULL;
30 fpGetBestRoute2_t ares_fpGetBestRoute2 = ZERO_NULL;
31 #endif
32
33 #if defined(ANDROID) || defined(__ANDROID__)
34 #include "ares_android.h"
35 #endif
36
37 /* library-private global vars with source visibility restricted to this file */
38
39 static unsigned int ares_initialized;
40 static int ares_init_flags;
41
42 /* library-private global vars with visibility across the whole library */
43
44 /* Some systems may return either NULL or a valid pointer on malloc(0). c-ares should
45 * never call malloc(0) so lets return NULL so we're more likely to find an issue if it
46 * were to occur. */
47
default_malloc(size_t size)48 static void *default_malloc(size_t size) { if (size == 0) { return NULL; } return malloc(size); }
49
50 #if defined(WIN32)
51 /* We need indirections to handle Windows DLL rules. */
default_realloc(void * p,size_t size)52 static void *default_realloc(void *p, size_t size) { return realloc(p, size); }
default_free(void * p)53 static void default_free(void *p) { free(p); }
54 #else
55 # define default_realloc realloc
56 # define default_free free
57 #endif
58 void *(*ares_malloc)(size_t size) = default_malloc;
59 void *(*ares_realloc)(void *ptr, size_t size) = default_realloc;
60 void (*ares_free)(void *ptr) = default_free;
61
62 #ifdef USE_WINSOCK
63 static HMODULE hnd_iphlpapi;
64 static HMODULE hnd_advapi32;
65 #endif
66
67
ares_win32_init(void)68 static int ares_win32_init(void)
69 {
70 #ifdef USE_WINSOCK
71
72 hnd_iphlpapi = 0;
73 hnd_iphlpapi = LoadLibraryW(L"iphlpapi.dll");
74 if (!hnd_iphlpapi)
75 return ARES_ELOADIPHLPAPI;
76
77 ares_fpGetNetworkParams = (fpGetNetworkParams_t)
78 GetProcAddress(hnd_iphlpapi, "GetNetworkParams");
79 if (!ares_fpGetNetworkParams)
80 {
81 FreeLibrary(hnd_iphlpapi);
82 return ARES_EADDRGETNETWORKPARAMS;
83 }
84
85 ares_fpGetAdaptersAddresses = (fpGetAdaptersAddresses_t)
86 GetProcAddress(hnd_iphlpapi, "GetAdaptersAddresses");
87 if (!ares_fpGetAdaptersAddresses)
88 {
89 /* This can happen on clients before WinXP, I don't
90 think it should be an error, unless we don't want to
91 support Windows 2000 anymore */
92 }
93
94 ares_fpGetBestRoute2 = (fpGetBestRoute2_t)
95 GetProcAddress(hnd_iphlpapi, "GetBestRoute2");
96 if (!ares_fpGetBestRoute2)
97 {
98 /* This can happen on clients before Vista, I don't
99 think it should be an error, unless we don't want to
100 support Windows XP anymore */
101 }
102
103 /*
104 * When advapi32.dll is unavailable or advapi32.dll has no SystemFunction036,
105 * also known as RtlGenRandom, which is the case for Windows versions prior
106 * to WinXP then c-ares uses portable rand() function. Then don't error here.
107 */
108
109 hnd_advapi32 = 0;
110 hnd_advapi32 = LoadLibraryW(L"advapi32.dll");
111 if (hnd_advapi32)
112 {
113 ares_fpSystemFunction036 = (fpSystemFunction036_t)
114 GetProcAddress(hnd_advapi32, "SystemFunction036");
115 }
116
117 #endif
118 return ARES_SUCCESS;
119 }
120
121
ares_win32_cleanup(void)122 static void ares_win32_cleanup(void)
123 {
124 #ifdef USE_WINSOCK
125 if (hnd_advapi32)
126 FreeLibrary(hnd_advapi32);
127 if (hnd_iphlpapi)
128 FreeLibrary(hnd_iphlpapi);
129 #endif
130 }
131
132
ares_library_init(int flags)133 int ares_library_init(int flags)
134 {
135 int res;
136
137 if (ares_initialized)
138 {
139 ares_initialized++;
140 return ARES_SUCCESS;
141 }
142 ares_initialized++;
143
144 if (flags & ARES_LIB_INIT_WIN32)
145 {
146 res = ares_win32_init();
147 if (res != ARES_SUCCESS)
148 return res; /* LCOV_EXCL_LINE: can't test Win32 init failure */
149 }
150
151 ares_init_flags = flags;
152
153 return ARES_SUCCESS;
154 }
155
ares_library_init_mem(int flags,void * (* amalloc)(size_t size),void (* afree)(void * ptr),void * (* arealloc)(void * ptr,size_t size))156 int ares_library_init_mem(int flags,
157 void *(*amalloc)(size_t size),
158 void (*afree)(void *ptr),
159 void *(*arealloc)(void *ptr, size_t size))
160 {
161 if (amalloc)
162 ares_malloc = amalloc;
163 if (arealloc)
164 ares_realloc = arealloc;
165 if (afree)
166 ares_free = afree;
167 return ares_library_init(flags);
168 }
169
170
ares_library_cleanup(void)171 void ares_library_cleanup(void)
172 {
173 if (!ares_initialized)
174 return;
175 ares_initialized--;
176 if (ares_initialized)
177 return;
178
179 if (ares_init_flags & ARES_LIB_INIT_WIN32)
180 ares_win32_cleanup();
181
182 #if defined(ANDROID) || defined(__ANDROID__)
183 ares_library_cleanup_android();
184 #endif
185
186 ares_init_flags = ARES_LIB_INIT_NONE;
187 ares_malloc = malloc;
188 ares_realloc = realloc;
189 ares_free = free;
190 }
191
192
ares_library_initialized(void)193 int ares_library_initialized(void)
194 {
195 #ifdef USE_WINSOCK
196 if (!ares_initialized)
197 return ARES_ENOTINITIALIZED;
198 #endif
199 return ARES_SUCCESS;
200 }
201