nextcloud-desktop/admin/win/tools/NCMsiHelper/LogResult.cpp

/*
 * Copyright (C) by Michael Schuster <michael.schuster@nextcloud.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 * 
 * Parts of this file are based on:
 * https://www.codeproject.com/articles/570751/devmsi-an-example-cplusplus-msi-wix-deferred-custo
 * 
 * Licensed under the The Code Project Open License (CPOL):
 * https://www.codeproject.com/info/cpol10.aspx
 * 
 */

#include "NCTools.h"
#include "NCMsiHelper.h"

//
// This code modified from MSDN article 256348
// "How to obtain error message descriptions using the FormatMessage API"
// Currently found at http://support.microsoft.com/kb/256348/en-us

#define ERRMSGBUFFERSIZE 256

/**
 * Use FormatMessage() to look an error code and log the error text.
 *
 * @param dwErrorMsgId The error code to be investigated.
 */
void LogError(DWORD dwErrorMsgId)
{
    HLOCAL pBuffer = nullptr;   // Buffer to hold the textual error description.
    DWORD ret = 0;              // Temp space to hold a return value.
    HINSTANCE hInst = nullptr;  // Instance handle for DLL.
    bool doLookup = true;
    DWORD dwMessageId = dwErrorMsgId;
    LPCSTR pMessage = "Error %d";
    DWORD flags = FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS;

    if (HRESULT_FACILITY(dwErrorMsgId) == FACILITY_MSMQ) {
        hInst = LoadLibrary(TEXT("MQUTIL.DLL"));
        flags |= FORMAT_MESSAGE_FROM_HMODULE;
        doLookup = (nullptr != hInst);
    } else if (dwErrorMsgId >= NERR_BASE && dwErrorMsgId <= MAX_NERR) {
        hInst = LoadLibrary(TEXT("NETMSG.DLL"));
        flags |= FORMAT_MESSAGE_FROM_HMODULE;
        doLookup = (nullptr != hInst);
    } else if (HRESULT_FACILITY(dwErrorMsgId) == FACILITY_WIN32) {
        // A "GetLastError" error, drop the HRESULT_FACILITY
        dwMessageId &= 0x0000FFFF;
        flags |= FORMAT_MESSAGE_FROM_SYSTEM;
    }

    if (doLookup) {
        ret = FormatMessageA( 
            flags,
            hInst, // Handle to the DLL.
            dwMessageId, // Message identifier.
            MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language.
            (LPSTR)&pBuffer, // Buffer that will hold the text string.
            ERRMSGBUFFERSIZE, // Allocate at least this many chars for pBuffer.
            nullptr // No insert values.
        );
    }

    if (0 < ret && nullptr != pBuffer) {
        pMessage = (LPSTR)pBuffer;
    }

    // Display the string.
    if (WcaIsInitialized()) {
        WcaLogError(dwErrorMsgId, pMessage, dwMessageId);
    } else { 
        // Log to stdout/stderr
        fprintf_s(stderr, pMessage, dwMessageId);
        if ('\n' != pMessage[strlen(pMessage) - 1]) {
            fprintf_s(stderr, "\n");
        }
    }

    // Free the buffer.
    LocalFree(pBuffer);
}

void LogResult(
    __in HRESULT hr,
    __in_z __format_string PCSTR fmt, ...
    )
{
    // This code taken from MSDN vsprintf example found currently at
    // http://msdn.microsoft.com/en-us/library/28d5ce15(v=vs.71).aspx
    // ...and then modified... because it doesn't seem to work!
    va_list args;

    va_start(args, fmt);
#pragma warning(push)
#pragma warning(disable : 4996)
    auto len = _vsnprintf(nullptr, 0, fmt, args) + 1;
#pragma warning(pop)
    auto buffer = (char*)malloc(len * sizeof(char));

#ifdef _DEBUG
    ::ZeroMemory(buffer, len);
#endif // _DEBUG
    _vsnprintf_s(buffer, len, len-1, fmt, args);

    // (MSDN code complete)

    // Now that the buffer holds the formatted string, send it to
    // the appropriate output.
    if (WcaIsInitialized())
    {
        if (FAILED(hr)) {
            WcaLogError(hr, buffer);
            LogError(hr);
        } else {
            WcaLog(LOGMSG_STANDARD, buffer);
        }
    } else { // Log to stdout/stderr
        if (FAILED(hr))
        {
            fprintf_s(stderr, "%s\n", buffer);
            LogError(hr);
        } else {
            fprintf_s(stdout, "%s\n", buffer);
        }
    }

    free(buffer);
}