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 "qemu/osdep.h" 14 #include <windows.h> 15 #include "qemu/error-report.h" 16 #include "qga/guest-agent-core.h" 17 #include "qga/vss-win32.h" 18 #include "qga/vss-win32/requester.h" 19 20 #define QGA_VSS_DLL "qga-vss.dll" 21 22 static HMODULE provider_lib; 23 24 /* Call a function in qga-vss.dll with the specified name */ 25 static HRESULT call_vss_provider_func(const char *func_name) 26 { 27 FARPROC WINAPI func; 28 29 g_assert(provider_lib); 30 31 func = GetProcAddress(provider_lib, func_name); 32 if (!func) { 33 char *msg; 34 FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | 35 FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(), 36 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 37 (char *)&msg, 0, NULL); 38 fprintf(stderr, "failed to load %s from %s: %s", 39 func_name, QGA_VSS_DLL, msg); 40 LocalFree(msg); 41 return E_FAIL; 42 } 43 44 return func(); 45 } 46 47 /* Check whether this OS version supports VSS providers */ 48 static bool vss_check_os_version(void) 49 { 50 OSVERSIONINFO OSver; 51 52 OSver.dwOSVersionInfoSize = sizeof(OSVERSIONINFO); 53 GetVersionEx(&OSver); 54 if ((OSver.dwMajorVersion == 5 && OSver.dwMinorVersion >= 2) || 55 OSver.dwMajorVersion > 5) { 56 BOOL wow64 = false; 57 #ifndef _WIN64 58 /* Provider doesn't work under WOW64 (32bit agent on 64bit OS) */ 59 if (!IsWow64Process(GetCurrentProcess(), &wow64)) { 60 fprintf(stderr, "failed to IsWow64Process (Error: %lx\n)\n", 61 GetLastError()); 62 return false; 63 } 64 if (wow64) { 65 warn_report("Running under WOW64"); 66 } 67 #endif 68 return !wow64; 69 } 70 return false; 71 } 72 73 /* Load qga-vss.dll */ 74 bool vss_init(bool init_requester) 75 { 76 if (!vss_check_os_version()) { 77 /* Do nothing if OS doesn't support providers. */ 78 fprintf(stderr, "VSS provider is not supported in this OS version: " 79 "fsfreeze is disabled.\n"); 80 return false; 81 } 82 83 provider_lib = LoadLibraryA(QGA_VSS_DLL); 84 if (!provider_lib) { 85 char *msg; 86 FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | 87 FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(), 88 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 89 (char *)&msg, 0, NULL); 90 fprintf(stderr, "failed to load %s: %sfsfreeze is disabled\n", 91 QGA_VSS_DLL, msg); 92 LocalFree(msg); 93 return false; 94 } 95 96 if (init_requester) { 97 HRESULT hr = call_vss_provider_func("requester_init"); 98 if (FAILED(hr)) { 99 fprintf(stderr, "fsfreeze is disabled.\n"); 100 vss_deinit(false); 101 return false; 102 } 103 } 104 105 return true; 106 } 107 108 /* Unload qga-provider.dll */ 109 void vss_deinit(bool deinit_requester) 110 { 111 if (deinit_requester) { 112 call_vss_provider_func("requester_deinit"); 113 } 114 FreeLibrary(provider_lib); 115 provider_lib = NULL; 116 } 117 118 bool vss_initialized(void) 119 { 120 return !!provider_lib; 121 } 122 123 int ga_install_vss_provider(void) 124 { 125 HRESULT hr; 126 127 if (!vss_init(false)) { 128 fprintf(stderr, "Installation of VSS provider is skipped. " 129 "fsfreeze will be disabled.\n"); 130 return 0; 131 } 132 hr = call_vss_provider_func("COMRegister"); 133 vss_deinit(false); 134 135 return SUCCEEDED(hr) ? 0 : EXIT_FAILURE; 136 } 137 138 void ga_uninstall_vss_provider(void) 139 { 140 if (!vss_init(false)) { 141 fprintf(stderr, "Removal of VSS provider is skipped.\n"); 142 return; 143 } 144 call_vss_provider_func("COMUnregister"); 145 vss_deinit(false); 146 } 147 148 /* Call VSS requester and freeze/thaw filesystems and applications */ 149 void qga_vss_fsfreeze(int *nr_volume, bool freeze, Error **errp) 150 { 151 const char *func_name = freeze ? "requester_freeze" : "requester_thaw"; 152 QGAVSSRequesterFunc func; 153 ErrorSet errset = { 154 .error_setg_win32_wrapper = error_setg_win32_internal, 155 .errp = errp, 156 }; 157 158 g_assert(errp); /* requester.cpp requires it */ 159 func = (QGAVSSRequesterFunc)GetProcAddress(provider_lib, func_name); 160 if (!func) { 161 error_setg_win32(errp, GetLastError(), "failed to load %s from %s", 162 func_name, QGA_VSS_DLL); 163 return; 164 } 165 166 func(nr_volume, &errset); 167 } 168