1 /* 2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "iphlp_interface.hpp" 26 #include "runtime/os.hpp" 27 28 // IPHLP API 29 typedef DWORD(WINAPI *GetIfTable2_Fn)(PMIB_IF_TABLE2*); 30 typedef DWORD(WINAPI *FreeMibTable_Fn)(PVOID); 31 32 // IPHLP statics 33 GetIfTable2_Fn IphlpDll::_GetIfTable2 = NULL; 34 FreeMibTable_Fn IphlpDll::_FreeMibTable = NULL; 35 36 LONG IphlpDll::_critical_section = 0; 37 LONG IphlpDll::_initialized = 0; 38 LONG IphlpDll::_iphlp_reference_count = 0; 39 HMODULE IphlpDll::_hModule = NULL; 40 41 void IphlpDll::initialize(void) { 42 _hModule = os::win32::load_Windows_dll("iphlpapi.dll", NULL, 0); 43 44 if (NULL == _hModule) { 45 return; 46 } 47 48 // The 'A' at the end means the ANSI (not the UNICODE) vesions of the methods 49 _GetIfTable2 = (GetIfTable2_Fn)::GetProcAddress(_hModule, "GetIfTable2"); 50 _FreeMibTable = (FreeMibTable_Fn)::GetProcAddress(_hModule, "FreeMibTable"); 51 52 // interlock is used for fencing 53 InterlockedExchange(&_initialized, 1); 54 } 55 56 bool IphlpDll::IphlpDetach(void) { 57 LONG prev_ref_count = InterlockedExchangeAdd(&_iphlp_reference_count, -1); 58 BOOL ret = false; 59 60 if (1 == prev_ref_count) { 61 if (_initialized && _hModule != NULL) { 62 ret = FreeLibrary(_hModule); 63 if (ret) { 64 _hModule = NULL; 65 _GetIfTable2 = NULL; 66 _FreeMibTable = NULL; 67 InterlockedExchange(&_initialized, 0); 68 } 69 } 70 } 71 return ret != 0; 72 } 73 74 bool IphlpDll::IphlpAttach(void) { 75 InterlockedExchangeAdd(&_iphlp_reference_count, 1); 76 77 if (1 == _initialized) { 78 return true; 79 } 80 81 while (InterlockedCompareExchange(&_critical_section, 1, 0) == 1); 82 83 if (0 == _initialized) { 84 initialize(); 85 } 86 87 while (InterlockedCompareExchange(&_critical_section, 0, 1) == 0); 88 89 return (_GetIfTable2 != NULL && _FreeMibTable != NULL); 90 } 91 92 DWORD IphlpDll::GetIfTable2(PMIB_IF_TABLE2* Table) { 93 assert(_initialized && _GetIfTable2 != NULL, 94 "IphlpAttach() not yet called"); 95 96 return _GetIfTable2(Table); 97 } 98 99 DWORD IphlpDll::FreeMibTable(PVOID Memory) { 100 assert(_initialized && _FreeMibTable != NULL, 101 "IphlpAttach() not yet called"); 102 103 return _FreeMibTable(Memory); 104 }