Cppcheck report - LibreOffice 2020-06-13 19:58:00 41c465b5ee443ec04441077b5eb80f263336ea8a, CppCheck 2020-06-13 18:19:47 6d5d12f283cf568d2dfe09aa77cb41f34b322d62: setup_native/source/win32/customactions/inst_msu/inst_msu.cxx

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

#include <memory>
#include <string>
#include <sstream>
#include <iomanip>

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <Shlobj.h>
#include <Wuerror.h>
#include <msiquery.h>

namespace
{
template <typename IntType> std::string Num2Hex(IntType n)
{
    std::stringstream sMsg;
    sMsg << "0x" << std::uppercase << std::setfill('0') << std::setw(sizeof(n) * 2) << std::hex
         << n;
    return sMsg.str();
}

template <typename IntType> std::string Num2Dec(IntType n)
{
    std::stringstream sMsg;
    sMsg << n;
    return sMsg.str();
}

std::string Win32ErrorMessage(const char* sFunc, DWORD nWin32Error)
{
    std::stringstream sMsg;
    sMsg << sFunc << " failed with Win32 error code " << Num2Hex(nWin32Error) << "!";

    return sMsg.str();
}

void ThrowHResult(const char* sFunc, HRESULT hr)
{
    std::stringstream sMsg;
    sMsg << sFunc << " failed (HRESULT = " << Num2Hex(hr) << ")!";

    throw std::exception(sMsg.str().c_str());
}

void CheckHResult(const char* sFunc, HRESULT hr)
{
    if (FAILED(hr))
        ThrowHResult(sFunc, hr);
}

void ThrowWin32Error(const char* sFunc, DWORD nWin32Error)
{
    throw std::exception(Win32ErrorMessage(sFunc, nWin32Error).c_str());
}

void ThrowLastError(const char* sFunc) { ThrowWin32Error(sFunc, GetLastError()); }

void CheckWin32Error(const char* sFunc, DWORD nWin32Error)
{
    if (nWin32Error != ERROR_SUCCESS)
        ThrowWin32Error(sFunc, nWin32Error);
}

std::wstring GetKnownFolder(const KNOWNFOLDERID& rfid)
{
    PWSTR sPath = nullptr;
    HRESULT hr = SHGetKnownFolderPath(rfid, KF_FLAG_DEFAULT, nullptr, &sPath);
    CheckHResult("SHGetKnownFolderPath", hr);
    std::wstring sResult(sPath);
    CoTaskMemFree(sPath);
    return sResult;
}

void WriteLogElem(MSIHANDLE hInst, MSIHANDLE hRecord, std::ostringstream& sTmpl, UINT)
{
    MsiRecordSetStringA(hRecord, 0, sTmpl.str().c_str());
    MsiProcessMessage(hInst, INSTALLMESSAGE_INFO, hRecord);
}

void RecSetString(MSIHANDLE hRec, UINT nField, LPCSTR sVal)
{
    MsiRecordSetStringA(hRec, nField, sVal);
}

void RecSetString(MSIHANDLE hRec, UINT nField, LPCWSTR sVal)
{
    MsiRecordSetStringW(hRec, nField, sVal);
}

template <class Ch, class... SOther>
void WriteLogElem(MSIHANDLE hInst, MSIHANDLE hRec, std::ostringstream& sTmpl, UINT nField,
                  const Ch* elem, const SOther&... others)
{
    sTmpl << " [" << nField << "]";
    RecSetString(hRec, nField, elem);
    WriteLogElem(hInst, hRec, sTmpl, nField + 1, others...);
}

template <class S1, class... SOther>
void WriteLogElem(MSIHANDLE hInst, MSIHANDLE hRec, std::ostringstream& sTmpl, UINT nField,
                  const S1& elem, const SOther&... others)
{
    WriteLogElem(hInst, hRec, sTmpl, nField, elem.c_str(), others...);
}

static std::string sLogPrefix;

template <class... StrType> void WriteLog(MSIHANDLE hInst, const StrType&... elements)
{
    PMSIHANDLE hRec = MsiCreateRecord(sizeof...(elements));
    if (!hRec)
        return;

    std::ostringstream sTemplate;
    sTemplate << sLogPrefix;
    WriteLogElem(hInst, hRec, sTemplate, 1, elements...);
}

// Show a warning message box. This will be automatically suppressed in unattended installation.
void ShowWarning(MSIHANDLE hInst, const std::wstring& sKBNo, const char* sMessage)
{
    // Error table's message #25000: "Installing a pre-requisite [2] failed.
    // You might need to manually install it from Microsoft site to be able to run the product.[3]"
    PMSIHANDLE hRec = MsiCreateRecord(3);
    // To show a message from Error table, record's Field 0 must be null
    MsiRecordSetInteger(hRec, 1, 25000);
    MsiRecordSetStringW(hRec, 2, sKBNo.c_str());
    std::string s("\n");
    s += sMessage;
    MsiRecordSetStringA(hRec, 3, s.c_str());
    MsiProcessMessage(hInst, INSTALLMESSAGE_WARNING, hRec);
}

// Set custom action description visible in progress dialog
void SetStatusText(MSIHANDLE hInst, const std::wstring& actName, const std::wstring& actDesc)
{
    PMSIHANDLE hRec = MsiCreateRecord(3);
    // For INSTALLMESSAGE_ACTIONSTART, record's Field 0 must be null
    // Field 1: Action name - must be non-null
    MsiRecordSetStringW(hRec, 1, actName.c_str());
    // Field 2: Action description - displayed in dialog
    MsiRecordSetStringW(hRec, 2, actDesc.c_str());
    // Let Field 3 stay null - no action template
    MsiProcessMessage(hInst, INSTALLMESSAGE_ACTIONSTART, hRec);
}

typedef std::unique_ptr<void, decltype(&CloseHandle)> CloseHandleGuard;
CloseHandleGuard Guard(HANDLE h) { return CloseHandleGuard(h, CloseHandle); }

typedef std::unique_ptr<const wchar_t, decltype(&DeleteFileW)> DeleteFileGuard;
DeleteFileGuard Guard(const wchar_t* sFileName) { return DeleteFileGuard(sFileName, DeleteFileW); }

typedef std::unique_ptr<SC_HANDLE__, decltype(&CloseServiceHandle)> CloseServiceHandleGuard;
CloseServiceHandleGuard Guard(SC_HANDLE h)
{
    return CloseServiceHandleGuard(h, CloseServiceHandle);
}

std::wstring GetTempFile()
{
    wchar_t sPath[MAX_PATH + 1];
    DWORD nResult = GetTempPathW(sizeof(sPath) / sizeof(*sPath), sPath);
    if (!nResult)
        ThrowLastError("GetTempPathW");

    wchar_t sFile[MAX_PATH + 1];
    nResult = GetTempFileNameW(sPath, L"TMP", 0, sFile);
    if (!nResult)
        ThrowLastError("GetTempFileNameW");
    return sFile;
}

bool IsWow64Process()
{
#if !defined _WIN64
    BOOL bResult = FALSE;
    typedef BOOL(WINAPI * LPFN_ISWOW64PROCESS)(HANDLE, PBOOL);
    LPFN_ISWOW64PROCESS fnIsWow64Process = reinterpret_cast<LPFN_ISWOW64PROCESS>(
        GetProcAddress(GetModuleHandleW(L"kernel32"), "IsWow64Process"));

    if (fnIsWow64Process)
    {
        if (!fnIsWow64Process(GetCurrentProcess(), &bResult))
            ThrowLastError("IsWow64Process");
    }

    return bResult;
#else
    return false;
#endif
}

// This class uses MsiProcessMessage to check for user input: it returns IDCANCEL when user cancels
// installation. It throws a special exception, to be intercepted in main action function to return
// corresponding exit code.
class UserInputChecker
{
public:
    class eUserCancelled
    {
    };

    UserInputChecker(MSIHANDLE hInstall)
<--- Class 'UserInputChecker' has a constructor with 1 argument that is not explicit. [+]
Class 'UserInputChecker' has a constructor with 1 argument that is not explicit. Such constructors should in general be explicit for type safety reasons. Using the explicit keyword in the constructor means some mistakes when using the class can be avoided.
        : m_hInstall(hInstall)
        , m_hProgressRec(MsiCreateRecord(3))
    {
        // Use explicit progress messages
        MsiRecordSetInteger(m_hProgressRec, 1, 1);
        MsiRecordSetInteger(m_hProgressRec, 2, 1);
        MsiRecordSetInteger(m_hProgressRec, 3, 0);
        int nResult = MsiProcessMessage(m_hInstall, INSTALLMESSAGE_PROGRESS, m_hProgressRec);
        if (nResult == IDCANCEL)
            throw eUserCancelled();
        // Prepare the record to following progress update calls
        MsiRecordSetInteger(m_hProgressRec, 1, 2);
        MsiRecordSetInteger(m_hProgressRec, 2, 0); // step by 0 - don't move progress
        MsiRecordSetInteger(m_hProgressRec, 3, 0);
    }

    void ThrowIfUserCancelled()
    {
        // Check if user has cancelled
        int nResult = MsiProcessMessage(m_hInstall, INSTALLMESSAGE_PROGRESS, m_hProgressRec);
        if (nResult == IDCANCEL)
            throw eUserCancelled();
    }

private:
    MSIHANDLE m_hInstall;
    PMSIHANDLE m_hProgressRec;
};

// Checks if Windows Update service is disabled, and if it is, enables it temporarily.
// Also stops the service if it's currently running, because it seems that wusa.exe
// does not freeze when it starts the service itself.
class WUServiceEnabler
{
public:
    WUServiceEnabler(MSIHANDLE hInstall)
<--- Class 'WUServiceEnabler' has a constructor with 1 argument that is not explicit. [+]
Class 'WUServiceEnabler' has a constructor with 1 argument that is not explicit. Such constructors should in general be explicit for type safety reasons. Using the explicit keyword in the constructor means some mistakes when using the class can be avoided.
        : mhInstall(hInstall)
        , mhService(EnableWUService(hInstall))
    {
    }

    ~WUServiceEnabler()
    {
        try
        {
            if (mhService)
            {
                EnsureServiceEnabled(mhInstall, mhService.get(), false);
                StopService(mhInstall, mhService.get(), false);
            }
        }
        catch (std::exception& e)
        {
            WriteLog(mhInstall, e.what());
        }
    }

private:
    static CloseServiceHandleGuard EnableWUService(MSIHANDLE hInstall)
    {
        auto hSCM = Guard(OpenSCManagerW(nullptr, nullptr, SC_MANAGER_ALL_ACCESS));
        if (!hSCM)
            ThrowLastError("OpenSCManagerW");
        WriteLog(hInstall, "Opened service control manager");

        auto hService = Guard(OpenServiceW(hSCM.get(), L"wuauserv",
                                           SERVICE_QUERY_CONFIG | SERVICE_CHANGE_CONFIG
                                               | SERVICE_QUERY_STATUS | SERVICE_STOP));
        if (!hService)
            ThrowLastError("OpenServiceW");
        WriteLog(hInstall, "Obtained WU service handle");

        const DWORD nCurrentStatus = ServiceStatus(hInstall, hService.get());
        // Stop currently running service to prevent wusa.exe from hanging trying to detect if the
        // update is applicable (sometimes this freezes it ~indefinitely; it seems that it doesn't
        // happen if wusa.exe starts the service itself: https://superuser.com/questions/1044528/).
        // tdf#124794: Wait for service to stop.
        if (nCurrentStatus == SERVICE_RUNNING)
            StopService(hInstall, hService.get(), true);

        if (nCurrentStatus == SERVICE_RUNNING
            || !EnsureServiceEnabled(hInstall, hService.get(), true))
        {
            // No need to restore anything back, since we didn't change config
            hService.reset();
            WriteLog(hInstall, "Service configuration is unchanged");
        }

        return hService;
    }

    // Returns if the service configuration was actually changed
    static bool EnsureServiceEnabled(MSIHANDLE hInstall, SC_HANDLE hService, bool bEnabled)
    {
        bool bConfigChanged = false;

        DWORD nCbRequired = 0;
        if (!QueryServiceConfigW(hService, nullptr, 0, &nCbRequired))
        {
            if (DWORD nError = GetLastError(); nError != ERROR_INSUFFICIENT_BUFFER)
                ThrowWin32Error("QueryServiceConfigW", nError);
        }
        std::unique_ptr<char[]> pBuf(new char[nCbRequired]);
        LPQUERY_SERVICE_CONFIGW pConfig = reinterpret_cast<LPQUERY_SERVICE_CONFIGW>(pBuf.get());
        if (!QueryServiceConfigW(hService, pConfig, nCbRequired, &nCbRequired))
            ThrowLastError("QueryServiceConfigW");
        WriteLog(hInstall, "Obtained service config");

        DWORD eNewStartType = 0;
        if (bEnabled && pConfig->dwStartType == SERVICE_DISABLED)
        {
            bConfigChanged = true;
            eNewStartType = SERVICE_DEMAND_START;
            WriteLog(hInstall, "Service is disabled, and requested to enable");
        }
        else if (!bEnabled && pConfig->dwStartType != SERVICE_DISABLED)
        {
            bConfigChanged = true;
            eNewStartType = SERVICE_DISABLED;
            WriteLog(hInstall, "Service is enabled, and requested to disable");
        }

        if (bConfigChanged)
        {
            if (!ChangeServiceConfigW(hService, SERVICE_NO_CHANGE, eNewStartType, SERVICE_NO_CHANGE,
                                      nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                                      nullptr))
                ThrowLastError("ChangeServiceConfigW");
            WriteLog(hInstall, "WU service config successfully changed");
        }
        else
            WriteLog(hInstall, "No need to modify service config");

        return bConfigChanged;
    }

    static DWORD ServiceStatus(MSIHANDLE hInstall, SC_HANDLE hService)
    {
        SERVICE_STATUS aServiceStatus{};
        if (!QueryServiceStatus(hService, &aServiceStatus))
            ThrowLastError("QueryServiceStatus");

        std::string sStatus;
        switch (aServiceStatus.dwCurrentState)
        {
            case SERVICE_STOPPED:
                sStatus = "SERVICE_STOPPED";
                break;
            case SERVICE_START_PENDING:
                sStatus = "SERVICE_START_PENDING";
                break;
            case SERVICE_STOP_PENDING:
                sStatus = "SERVICE_STOP_PENDING";
                break;
            case SERVICE_RUNNING:
                sStatus = "SERVICE_RUNNING";
                break;
            case SERVICE_CONTINUE_PENDING:
                sStatus = "SERVICE_CONTINUE_PENDING";
                break;
            case SERVICE_PAUSE_PENDING:
                sStatus = "SERVICE_PAUSE_PENDING";
                break;
            case SERVICE_PAUSED:
                sStatus = "SERVICE_PAUSED";
                break;
            default:
                sStatus = Num2Hex(aServiceStatus.dwCurrentState);
        }
        WriteLog(hInstall, "Service status is", sStatus);

        return aServiceStatus.dwCurrentState;
    }

    static void StopService(MSIHANDLE hInstall, SC_HANDLE hService, bool bWait)
    {
        try
        {
            if (ServiceStatus(hInstall, hService) != SERVICE_STOPPED)
            {
                SERVICE_STATUS aServiceStatus{};
                if (!ControlService(hService, SERVICE_CONTROL_STOP, &aServiceStatus))
                    ThrowLastError("ControlService");
                WriteLog(hInstall,
                         "Successfully sent SERVICE_CONTROL_STOP code to Windows Update service");
                if (aServiceStatus.dwCurrentState != SERVICE_STOPPED && bWait)
                {
                    // Let user cancel too long wait
                    UserInputChecker aInputChecker(hInstall);
                    // aServiceStatus.dwWaitHint is unreasonably high for Windows Update (30000),
                    // so don't use it, but simply poll service status each second
                    for (int nWait = 0; nWait < 30; ++nWait) // arbitrary limit of 30 s
                    {
                        for (int i = 0; i < 2; ++i) // check user input twice a second
                        {
                            Sleep(500);
                            aInputChecker.ThrowIfUserCancelled();
                        }

                        if (!QueryServiceStatus(hService, &aServiceStatus))
                            ThrowLastError("QueryServiceStatus");

                        if (aServiceStatus.dwCurrentState == SERVICE_STOPPED)
                            break;
                    }
                }
                if (aServiceStatus.dwCurrentState == SERVICE_STOPPED)
                    WriteLog(hInstall, "Successfully stopped Windows Update service");
                else if (bWait)
                    WriteLog(hInstall, "Wait for Windows Update stop timed out - proceeding");
            }
            else
                WriteLog(hInstall, "Windows Update service is not running");
        }
        catch (std::exception& e)
        {
            WriteLog(hInstall, e.what());
        }
    }

    MSIHANDLE mhInstall;
    CloseServiceHandleGuard mhService;
};
}

// Immediate action "unpack_msu" that has access to installation database and properties; checks
// "InstMSUBinary" property and unpacks the binary with that name to a temporary file; sets
// "cleanup_msu" and "inst_msu" properties to the full name of the extracted temporary file. These
// properties will become "CustomActionData" property inside relevant deferred actions.
extern "C" __declspec(dllexport) UINT __stdcall UnpackMSUForInstall(MSIHANDLE hInstall)<--- The function 'UnpackMSUForInstall' is never used.
{
    try
    {
        sLogPrefix = "UnpackMSUForInstall:";
        WriteLog(hInstall, "started");

        WriteLog(hInstall, "Checking value of InstMSUBinary");
        wchar_t sInstMSUBinary[MAX_PATH + 10];
        DWORD nCCh = sizeof(sInstMSUBinary) / sizeof(*sInstMSUBinary);
        CheckWin32Error("MsiGetPropertyW",
                        MsiGetPropertyW(hInstall, L"InstMSUBinary", sInstMSUBinary, &nCCh));
        WriteLog(hInstall, "Got InstMSUBinary value:",
                 sInstMSUBinary); // KB2999226|Windows61-KB2999226-x64msu
        const wchar_t* sBinaryName = wcschr(sInstMSUBinary, L'|');
        if (!sBinaryName)
            throw std::exception("No KB number in InstMSUBinary!");
        // "KB2999226"
        const std::wstring sKBNo(sInstMSUBinary, sBinaryName - sInstMSUBinary);
        ++sBinaryName;

        PMSIHANDLE hDatabase = MsiGetActiveDatabase(hInstall);
        if (!hDatabase)
            ThrowLastError("MsiGetActiveDatabase");
        WriteLog(hInstall, "MsiGetActiveDatabase succeeded");

        std::wstringstream sQuery;
        sQuery << "SELECT `Data` FROM `Binary` WHERE `Name`='" << sBinaryName << "'";

        PMSIHANDLE hBinaryView;
        CheckWin32Error("MsiDatabaseOpenViewW",
                        MsiDatabaseOpenViewW(hDatabase, sQuery.str().c_str(), &hBinaryView));
        WriteLog(hInstall, "MsiDatabaseOpenViewW succeeded");

        CheckWin32Error("MsiViewExecute", MsiViewExecute(hBinaryView, 0));
        WriteLog(hInstall, "MsiViewExecute succeeded");

        PMSIHANDLE hBinaryRecord;
        CheckWin32Error("MsiViewFetch", MsiViewFetch(hBinaryView, &hBinaryRecord));
        WriteLog(hInstall, "MsiViewFetch succeeded");

        const std::wstring sBinary = GetTempFile();
        auto aDeleteFileGuard(Guard(sBinary.c_str()));
        WriteLog(hInstall, "Temp file path:", sBinary.c_str());

        CheckWin32Error("MsiSetPropertyW",
                        MsiSetPropertyW(hInstall, L"cleanup_msu", sBinary.c_str()));

        {
            HANDLE hFile = CreateFileW(sBinary.c_str(), GENERIC_WRITE, 0, nullptr, CREATE_ALWAYS,
                                       FILE_ATTRIBUTE_NORMAL, nullptr);
            if (hFile == INVALID_HANDLE_VALUE)
                ThrowLastError("CreateFileW");
            auto aFileHandleGuard(Guard(hFile));

            const DWORD nBufSize = 1024 * 1024;
            std::unique_ptr<char[]> buf(new char[nBufSize]);
            DWORD nTotal = 0;
            DWORD nRead;
            do
            {
                nRead = nBufSize;
                CheckWin32Error("MsiRecordReadStream",
                                MsiRecordReadStream(hBinaryRecord, 1, buf.get(), &nRead));

                if (nRead > 0)
                {
                    DWORD nWritten;
                    if (!WriteFile(hFile, buf.get(), nRead, &nWritten, nullptr))
                        ThrowLastError("WriteFile");
                    nTotal += nWritten;
                }
            } while (nRead == nBufSize);

            WriteLog(hInstall, "Successfully wrote", Num2Dec(nTotal), "bytes");
        }
        const std::wstring s_inst_msu = sKBNo + L"|" + sBinary;
        CheckWin32Error("MsiSetPropertyW",
                        MsiSetPropertyW(hInstall, L"inst_msu", s_inst_msu.c_str()));

        // Don't delete the file: it will be done by following actions (inst_msu or cleanup_msu)
        (void)aDeleteFileGuard.release();
        return ERROR_SUCCESS;
    }
    catch (std::exception& e)
    {
        WriteLog(hInstall, e.what());
    }
    return ERROR_INSTALL_FAILURE;
}

// Deferred action "inst_msu" that must be run from system account. Receives the tempfile name from
// "CustomActionData" property, and runs wusa.exe to install it. Waits for it and checks exit code.
extern "C" __declspec(dllexport) UINT __stdcall InstallMSU(MSIHANDLE hInstall)<--- The function 'InstallMSU' is never used.
{
    std::wstring sKBNo; // "KB2999226"
    try
    {
        sLogPrefix = "InstallMSU:";
        WriteLog(hInstall, "started");

        WriteLog(hInstall, "Checking value of CustomActionData");
        wchar_t sCustomActionData[MAX_PATH + 10]; // "KB2999226|C:\Temp\binary.tmp"
        DWORD nCCh = sizeof(sCustomActionData) / sizeof(*sCustomActionData);
        CheckWin32Error("MsiGetPropertyW",
                        MsiGetPropertyW(hInstall, L"CustomActionData", sCustomActionData, &nCCh));
        WriteLog(hInstall, "Got CustomActionData value:", sCustomActionData);
        const wchar_t* sBinaryName = wcschr(sCustomActionData, L'|');
        if (!sBinaryName)
            throw std::exception("No KB number in CustomActionData!");
        sKBNo = std::wstring(sCustomActionData, sBinaryName - sCustomActionData);
        ++sBinaryName;
        auto aDeleteFileGuard(Guard(sBinaryName));

        SetStatusText(hInstall, L"WU service state check",
                      L"Checking Windows Update service state");

        // In case the Windows Update service is disabled, we temporarily enable it here. We also
        // stop running WU service, to avoid wusa.exe freeze (see comment in EnableWUService).
        WUServiceEnabler aWUServiceEnabler(hInstall);

        SetStatusText(hInstall, sKBNo + L" installation", L"Installing " + sKBNo);

        const bool bWow64Process = IsWow64Process();
        WriteLog(hInstall, "Is Wow64 Process:", bWow64Process ? "YES" : "NO");
        std::wstring sWUSAPath = bWow64Process ? GetKnownFolder(FOLDERID_Windows) + L"\\SysNative"
                                               : GetKnownFolder(FOLDERID_System);
        sWUSAPath += L"\\wusa.exe";
        WriteLog(hInstall, "Prepared wusa path:", sWUSAPath);

        std::wstring sWUSACmd
            = L"\"" + sWUSAPath + L"\" \"" + sBinaryName + L"\" /quiet /norestart";
        WriteLog(hInstall, "Prepared wusa command:", sWUSACmd);

        STARTUPINFOW si{};
        si.cb = sizeof(si);
        PROCESS_INFORMATION pi{};
        if (!CreateProcessW(sWUSAPath.c_str(), const_cast<LPWSTR>(sWUSACmd.c_str()), nullptr,
                            nullptr, FALSE, CREATE_NO_WINDOW, nullptr, nullptr, &si, &pi))
            ThrowLastError("CreateProcessW");
        CloseHandle(pi.hThread);
        auto aCloseProcHandleGuard(Guard(pi.hProcess));
        WriteLog(hInstall, "CreateProcessW succeeded");

        {
            // This block waits when the started wusa.exe process finishes. Since it's possible
            // for wusa.exe in some circumstances to wait really long (indefinitely?), we check
            // for user input here.
            UserInputChecker aInputChecker(hInstall);
            for (;;)
            {
                DWORD nWaitResult = WaitForSingleObject(pi.hProcess, 500);
                if (nWaitResult == WAIT_OBJECT_0)
                    break; // wusa.exe finished
                else if (nWaitResult == WAIT_TIMEOUT)
                    aInputChecker.ThrowIfUserCancelled();
                else
                    ThrowWin32Error("WaitForSingleObject", nWaitResult);
            }
        }

        DWORD nExitCode = 0;
        if (!GetExitCodeProcess(pi.hProcess, &nExitCode))
            ThrowLastError("GetExitCodeProcess");

        HRESULT hr = static_cast<HRESULT>(nExitCode);

        // HRESULT_FROM_WIN32 is defined as an inline function in SDK 8.1 without the constexpr
        // And it won't work to place it inside the switch statement.
        if (HRESULT_FROM_WIN32(ERROR_SUCCESS_REBOOT_REQUIRED) == hr)
        {
            hr = ERROR_SUCCESS_REBOOT_REQUIRED;
        }

        switch (hr)
        {
            case S_OK:
            case WU_S_ALREADY_INSTALLED:
            case WU_E_NOT_APPLICABLE: // Windows could lie us about its version, etc.
            case ERROR_SUCCESS_REBOOT_REQUIRED:
            case WU_S_REBOOT_REQUIRED:
                WriteLog(hInstall, "wusa.exe succeeded with exit code", Num2Hex(nExitCode));
                return ERROR_SUCCESS;

            default:
                ThrowHResult("Execution of wusa.exe", hr);
        }
    }
    catch (const UserInputChecker::eUserCancelled&)
    {
        return ERROR_INSTALL_USEREXIT;
    }
    catch (std::exception& e)
    {
        WriteLog(hInstall, e.what());
        ShowWarning(hInstall, sKBNo, e.what());
    }
    return ERROR_SUCCESS; // Do not break on MSU installation errors
}

// Rollback deferred action "cleanup_msu" that is executed on error or cancel.
// It removes the temporary file created by UnpackMSUForInstall action.
// MUST be placed IMMEDIATELY AFTER "unpack_msu" in execute sequence.
extern "C" __declspec(dllexport) UINT __stdcall CleanupMSU(MSIHANDLE hInstall)<--- The function 'CleanupMSU' is never used.
{
    try
    {
        sLogPrefix = "CleanupMSU:";
        WriteLog(hInstall, "started");

        WriteLog(hInstall, "Checking value of CustomActionData");
        wchar_t sBinaryName[MAX_PATH + 1];
        DWORD nCCh = sizeof(sBinaryName) / sizeof(*sBinaryName);
        CheckWin32Error("MsiGetPropertyW",
                        MsiGetPropertyW(hInstall, L"CustomActionData", sBinaryName, &nCCh));
        WriteLog(hInstall, "Got CustomActionData value:", sBinaryName);

        if (!DeleteFileW(sBinaryName))
        {
            if (DWORD nError = GetLastError(); nError != ERROR_FILE_NOT_FOUND)
                ThrowWin32Error("DeleteFileW", nError);
        }
        WriteLog(hInstall, "File successfully removed");
    }
    catch (std::exception& e)
    {
        WriteLog(hInstall, e.what());
    }
    // Always return success - we don't want rollback to fail.
    return ERROR_SUCCESS;
}

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