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 "qapi/error.h" 16 #include "qemu/error-report.h" 17 #include "guest-agent-core.h" 18 #include "vss-win32.h" 19 #include "vss-win32/requester.h" 20 21 #define QGA_VSS_DLL "qga-vss.dll" 22 23 static HMODULE provider_lib; 24 25 /* Call a function in qga-vss.dll with the specified name */ 26 static HRESULT call_vss_provider_func(const char *func_name) 27 { 28 FARPROC WINAPI func; 29 30 g_assert(provider_lib); 31 32 func = GetProcAddress(provider_lib, func_name); 33 if (!func) { 34 char *msg; 35 FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | 36 FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(), 37 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 38 (char *)&msg, 0, NULL); 39 fprintf(stderr, "failed to load %s from %s: %s", 40 func_name, QGA_VSS_DLL, msg); 41 LocalFree(msg); 42 return E_FAIL; 43 } 44 45 return func(); 46 } 47 48 /* Check whether this OS version supports VSS providers */ 49 static bool vss_check_os_version(void) 50 { 51 OSVERSIONINFO OSver; 52 53 OSver.dwOSVersionInfoSize = sizeof(OSVERSIONINFO); 54 GetVersionEx(&OSver); 55 if ((OSver.dwMajorVersion == 5 && OSver.dwMinorVersion >= 2) || 56 OSver.dwMajorVersion > 5) { 57 BOOL wow64 = false; 58 #ifndef _WIN64 59 /* Provider doesn't work under WOW64 (32bit agent on 64bit OS) */ 60 if (!IsWow64Process(GetCurrentProcess(), &wow64)) { 61 fprintf(stderr, "failed to IsWow64Process (Error: %lx\n)\n", 62 GetLastError()); 63 return false; 64 } 65 if (wow64) { 66 warn_report("Running under WOW64"); 67 } 68 #endif 69 return !wow64; 70 } 71 return false; 72 } 73 74 /* Load qga-vss.dll */ 75 bool vss_init(bool init_requester) 76 { 77 if (!vss_check_os_version()) { 78 /* Do nothing if OS doesn't support providers. */ 79 fprintf(stderr, "VSS provider is not supported in this OS version: " 80 "fsfreeze is disabled.\n"); 81 return false; 82 } 83 84 provider_lib = LoadLibraryA(QGA_VSS_DLL); 85 if (!provider_lib) { 86 char *msg; 87 FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | 88 FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(), 89 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 90 (char *)&msg, 0, NULL); 91 fprintf(stderr, "failed to load %s: %sfsfreeze is disabled\n", 92 QGA_VSS_DLL, msg); 93 LocalFree(msg); 94 return false; 95 } 96 97 if (init_requester) { 98 HRESULT hr = call_vss_provider_func("requester_init"); 99 if (FAILED(hr)) { 100 fprintf(stderr, "fsfreeze is disabled.\n"); 101 vss_deinit(false); 102 return false; 103 } 104 } 105 106 return true; 107 } 108 109 /* Unload qga-provider.dll */ 110 void vss_deinit(bool deinit_requester) 111 { 112 if (deinit_requester) { 113 call_vss_provider_func("requester_deinit"); 114 } 115 FreeLibrary(provider_lib); 116 provider_lib = NULL; 117 } 118 119 bool vss_initialized(void) 120 { 121 return !!provider_lib; 122 } 123 124 int ga_install_vss_provider(void) 125 { 126 HRESULT hr; 127 128 if (!vss_init(false)) { 129 fprintf(stderr, "Installation of VSS provider is skipped. " 130 "fsfreeze will be disabled.\n"); 131 return 0; 132 } 133 hr = call_vss_provider_func("COMRegister"); 134 vss_deinit(false); 135 136 return SUCCEEDED(hr) ? 0 : EXIT_FAILURE; 137 } 138 139 void ga_uninstall_vss_provider(void) 140 { 141 if (!vss_init(false)) { 142 fprintf(stderr, "Removal of VSS provider is skipped.\n"); 143 return; 144 } 145 call_vss_provider_func("COMUnregister"); 146 vss_deinit(false); 147 } 148 149 /* Call VSS requester and freeze/thaw filesystems and applications */ 150 void qga_vss_fsfreeze(int *nr_volume, bool freeze, 151 strList *mountpoints, Error **errp) 152 { 153 const char *func_name = freeze ? "requester_freeze" : "requester_thaw"; 154 QGAVSSRequesterFunc func; 155 ErrorSet errset = { 156 .error_setg_win32_wrapper = error_setg_win32_internal, 157 .errp = errp, 158 }; 159 160 g_assert(errp); /* requester.cpp requires it */ 161 func = (QGAVSSRequesterFunc)GetProcAddress(provider_lib, func_name); 162 if (!func) { 163 error_setg_win32(errp, GetLastError(), "failed to load %s from %s", 164 func_name, QGA_VSS_DLL); 165 return; 166 } 167 168 func(nr_volume, mountpoints, &errset); 169 } 170