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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 #endif
31 
32 /* library-private global vars with source visibility restricted to this file */
33 
34 static unsigned int ares_initialized;
35 static int          ares_init_flags;
36 
37 #ifdef USE_WINSOCK
38 static HMODULE hnd_iphlpapi;
39 static HMODULE hnd_advapi32;
40 #endif
41 
42 
ares_win32_init(void)43 static int ares_win32_init(void)
44 {
45 #ifdef USE_WINSOCK
46 
47   hnd_iphlpapi = 0;
48   hnd_iphlpapi = LoadLibrary("iphlpapi.dll");
49   if (!hnd_iphlpapi)
50     return ARES_ELOADIPHLPAPI;
51 
52   ares_fpGetNetworkParams = (fpGetNetworkParams_t)
53     GetProcAddress(hnd_iphlpapi, "GetNetworkParams");
54   if (!ares_fpGetNetworkParams)
55     {
56       FreeLibrary(hnd_iphlpapi);
57       return ARES_EADDRGETNETWORKPARAMS;
58     }
59 
60   ares_fpGetAdaptersAddresses = (fpGetAdaptersAddresses_t)
61     GetProcAddress(hnd_iphlpapi, "GetAdaptersAddresses");
62   if (!ares_fpGetAdaptersAddresses)
63     {
64       /* This can happen on clients before WinXP, I don't
65          think it should be an error, unless we don't want to
66          support Windows 2000 anymore */
67     }
68 
69   /*
70    * When advapi32.dll is unavailable or advapi32.dll has no SystemFunction036,
71    * also known as RtlGenRandom, which is the case for Windows versions prior
72    * to WinXP then c-ares uses portable rand() function. Then don't error here.
73    */
74 
75   hnd_advapi32 = 0;
76   hnd_advapi32 = LoadLibrary("advapi32.dll");
77   if (hnd_advapi32)
78     {
79       ares_fpSystemFunction036 = (fpSystemFunction036_t)
80         GetProcAddress(hnd_advapi32, "SystemFunction036");
81     }
82 
83 #endif
84   return ARES_SUCCESS;
85 }
86 
87 
ares_win32_cleanup(void)88 static void ares_win32_cleanup(void)
89 {
90 #ifdef USE_WINSOCK
91   if (hnd_advapi32)
92     FreeLibrary(hnd_advapi32);
93   if (hnd_iphlpapi)
94     FreeLibrary(hnd_iphlpapi);
95 #endif
96 }
97 
98 
ares_library_init(int flags)99 int ares_library_init(int flags)
100 {
101   int res;
102 
103   if (ares_initialized)
104     return ARES_SUCCESS;
105   ares_initialized++;
106 
107   if (flags & ARES_LIB_INIT_WIN32)
108     {
109       res = ares_win32_init();
110       if (res != ARES_SUCCESS)
111         return res;
112     }
113 
114   ares_init_flags = flags;
115 
116   return ARES_SUCCESS;
117 }
118 
119 
ares_library_cleanup(void)120 void ares_library_cleanup(void)
121 {
122   if (!ares_initialized)
123     return;
124   ares_initialized--;
125 
126   if (ares_init_flags & ARES_LIB_INIT_WIN32)
127     ares_win32_cleanup();
128 
129   ares_init_flags = ARES_LIB_INIT_NONE;
130 }
131 
132 
ares_library_initialized(void)133 int ares_library_initialized(void)
134 {
135 #ifdef USE_WINSOCK
136   if (!ares_initialized)
137     return ARES_ENOTINITIALIZED;
138 #endif
139   return ARES_SUCCESS;
140 }
141 
142 
143