WriteMinidumpForException

WriteMinidumpForException.cpp

#include <Windows.h>
#include <stdio.h>

// fullDump enables MiniDumpWithFullMemory, and results in dmp files to be over 100MB in size (as opposed to default which is only 100KB).
// With fullDump Visual Studio is able to display proper backtrace for unhandled c++ exception. Without fullDump WinDBG has to be used.
static int WriteMinidumpForException(EXCEPTION_POINTERS* e, bool fullDump)
{
    HMODULE dbghelp = LoadLibraryA("DbgHelp.dll"); // Note: no matching FreeLibrary
    if (!dbghelp)
        return EXCEPTION_CONTINUE_SEARCH;

    typedef	BOOL(WINAPI * MiniDumpWriteDump_func)(HANDLE hProcess, DWORD ProcessId, HANDLE hFile,
        DWORD DumpType, PVOID ExceptionParam, PVOID UserStreamParam, PVOID CallbackParam);

    MiniDumpWriteDump_func writeDump = (MiniDumpWriteDump_func)GetProcAddress(dbghelp, "MiniDumpWriteDump");
    if (!writeDump)
        return EXCEPTION_CONTINUE_SEARCH;

    char dmpSuffix[128];
    GetDateFormatA(LOCALE_NEUTRAL, 0, 0, "'.'MMM'_'dd'_'", dmpSuffix, sizeof(dmpSuffix) - 1);
    GetTimeFormatA(LOCALE_NEUTRAL, 0, 0, "HH'h'mm'm'ss's'", dmpSuffix + strlen(dmpSuffix), sizeof(dmpSuffix) - 1 - strlen(dmpSuffix));
    LARGE_INTEGER li;
    QueryPerformanceCounter(&li);
    sprintf(dmpSuffix + strlen(dmpSuffix), "_rnd%u", li.LowPart % 100000);
    strcat(dmpSuffix, ".dmp");

    WCHAR outfile[MAX_PATH + 128];
    GetModuleFileNameW(NULL, outfile, MAX_PATH); // use __ImageBase for dlls?
    for (int i = 0, plen = wcslen(outfile), dlen = 1 + strlen(dmpSuffix); i < dlen && i + plen < sizeof(outfile) / sizeof(outfile[0]); ++i)
        outfile[plen + i] = dmpSuffix[i];

    HANDLE fl = ::CreateFileW(outfile, GENERIC_READ | GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
    if (fl == INVALID_HANDLE_VALUE)
        return EXCEPTION_CONTINUE_SEARCH;

    struct MINIDUMP_EXCEPTION_INFORMATION
    {
        DWORD ThreadId;
        PEXCEPTION_POINTERS ExceptionPointers;
        BOOL ClientPointers;
    };
    MINIDUMP_EXCEPTION_INFORMATION excInfo;
    excInfo.ThreadId = GetCurrentThreadId();
    excInfo.ExceptionPointers = e;
    excInfo.ClientPointers = TRUE;
    DWORD dumpType = fullDump ? 2/*MiniDumpWithFullMemory*/ : 0/*MiniDumpNormal*/;
    if (!writeDump(GetCurrentProcess(), GetCurrentProcessId(), fl, dumpType, &excInfo, NULL, NULL))
        return EXCEPTION_CONTINUE_SEARCH;
    return EXCEPTION_EXECUTE_HANDLER;
}