1 /* 2 * QEMU Guest Agent VSS utility functions 3 * 4 * Copyright Hitachi Data Systems Corp. 2013 5 * 6 * Authors: 7 * Tomoki Sekiyama <tomoki.sekiyama@hds.com> 8 * 9 * This work is licensed under the terms of the GNU GPL, version 2 or later. 10 * See the COPYING file in the top-level directory. 11 */ 12 13 #include <stdio.h> 14 #include <windows.h> 15 #include "qga/guest-agent-core.h" 16 #include "qga/vss-win32.h" 17 #include "qga/vss-win32/requester.h" 18 19 #define QGA_VSS_DLL "qga-vss.dll" 20 21 static HMODULE provider_lib; 22 23 /* Call a function in qga-vss.dll with the specified name */ 24 static HRESULT call_vss_provider_func(const char *func_name) 25 { 26 FARPROC WINAPI func; 27 28 g_assert(provider_lib); 29 30 func = GetProcAddress(provider_lib, func_name); 31 if (!func) { 32 char *msg; 33 FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | 34 FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(), 35 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 36 (char *)&msg, 0, NULL); 37 fprintf(stderr, "failed to load %s from %s: %s", 38 func_name, QGA_VSS_DLL, msg); 39 LocalFree(msg); 40 return E_FAIL; 41 } 42 43 return func(); 44 } 45 46 /* Check whether this OS version supports VSS providers */ 47 static bool vss_check_os_version(void) 48 { 49 OSVERSIONINFO OSver; 50 51 OSver.dwOSVersionInfoSize = sizeof(OSVERSIONINFO); 52 GetVersionEx(&OSver); 53 if ((OSver.dwMajorVersion == 5 && OSver.dwMinorVersion >= 2) || 54 OSver.dwMajorVersion > 5) { 55 BOOL wow64 = false; 56 #ifndef _WIN64 57 /* Provider doesn't work under WOW64 (32bit agent on 64bit OS) */ 58 if (!IsWow64Process(GetCurrentProcess(), &wow64)) { 59 fprintf(stderr, "failed to IsWow64Process (Error: %lx\n)\n", 60 GetLastError()); 61 return false; 62 } 63 if (wow64) { 64 fprintf(stderr, "Warning: Running under WOW64\n"); 65 } 66 #endif 67 return !wow64; 68 } 69 return false; 70 } 71 72 /* Load qga-vss.dll */ 73 bool vss_init(bool init_requester) 74 { 75 if (!vss_check_os_version()) { 76 /* Do nothing if OS doesn't support providers. */ 77 fprintf(stderr, "VSS provider is not supported in this OS version: " 78 "fsfreeze is disabled.\n"); 79 return false; 80 } 81 82 provider_lib = LoadLibraryA(QGA_VSS_DLL); 83 if (!provider_lib) { 84 char *msg; 85 FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | 86 FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(), 87 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 88 (char *)&msg, 0, NULL); 89 fprintf(stderr, "failed to load %s: %sfsfreeze is disabled\n", 90 QGA_VSS_DLL, msg); 91 LocalFree(msg); 92 return false; 93 } 94 95 if (init_requester) { 96 HRESULT hr = call_vss_provider_func("requester_init"); 97 if (FAILED(hr)) { 98 fprintf(stderr, "fsfreeze is disabled.\n"); 99 vss_deinit(false); 100 return false; 101 } 102 } 103 104 return true; 105 } 106 107 /* Unload qga-provider.dll */ 108 void vss_deinit(bool deinit_requester) 109 { 110 if (deinit_requester) { 111 call_vss_provider_func("requester_deinit"); 112 } 113 FreeLibrary(provider_lib); 114 provider_lib = NULL; 115 } 116 117 bool vss_initialized(void) 118 { 119 return !!provider_lib; 120 } 121 122 int ga_install_vss_provider(void) 123 { 124 HRESULT hr; 125 126 if (!vss_init(false)) { 127 fprintf(stderr, "Installation of VSS provider is skipped. " 128 "fsfreeze will be disabled.\n"); 129 return 0; 130 } 131 hr = call_vss_provider_func("COMRegister"); 132 vss_deinit(false); 133 134 return SUCCEEDED(hr) ? 0 : EXIT_FAILURE; 135 } 136 137 void ga_uninstall_vss_provider(void) 138 { 139 if (!vss_init(false)) { 140 fprintf(stderr, "Removal of VSS provider is skipped.\n"); 141 return; 142 } 143 call_vss_provider_func("COMUnregister"); 144 vss_deinit(false); 145 } 146 147 /* Call VSS requester and freeze/thaw filesystems and applications */ 148 void qga_vss_fsfreeze(int *nr_volume, Error **err, bool freeze) 149 { 150 const char *func_name = freeze ? "requester_freeze" : "requester_thaw"; 151 QGAVSSRequesterFunc func; 152 ErrorSet errset = { 153 .error_set = (ErrorSetFunc)error_set_win32, 154 .errp = (void **)err, 155 .err_class = ERROR_CLASS_GENERIC_ERROR 156 }; 157 158 func = (QGAVSSRequesterFunc)GetProcAddress(provider_lib, func_name); 159 if (!func) { 160 error_setg_win32(err, GetLastError(), "failed to load %s from %s", 161 func_name, QGA_VSS_DLL); 162 return; 163 } 164 165 func(nr_volume, &errset); 166 } 167