qemu

FORK: QEMU emulator
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vss-win32.c (4648B)

      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 }