[C++知识库]etw监控文件操作开发示例

微软官方文档

Event Tracing - Win32 apps | Microsoft Docs

etw相关工具(目前主要用到logman查询providers)

Event Tracing Tools - Win32 apps | Microsoft Docs

简述：

windows事件跟踪也就是windows event trace(etw)。主要分为三个模块：事件提供者(provider)、事件控制器(controller)、事件订阅者(consumer)。普通程序员一般用系统提供的事件用来监听诸如文件操作，注册表操作。所以我们一般写的代码是consumer。但是事件提供者不会直接给订阅者发送消息，所以我们还要写一个控制器controller用来打开事件，让consumer接收事件。

所以我们要自己实现一个controller和一个consumer，可以在同一个程序里面实现，也可以在两个程序里面实现。

controller的实现

commonDef.h

#pragma once

// 这个名字就是控制器的名字
#define LOGSESSION_NAME L"My Event Trace Session 5"//KERNEL_LOGGER_NAMEW//

// 控制器的guid，唯一标识，重复打开会报错183
#define SESSION_GUID { 0xae44cb98, 0xbd11, 0x4069, { 0x80, 0x93, 0x77, 0xe, 0xc9, 0x25, 0x8a, 0x14 } }

#define ARR_SIZE(arr) (sizeof(arr)/sizeof(arr[0]))

// 下面两个guid，经过测试，发现微软官方文档里面mof class中的guid不能实现事件监听，consumer中的回调从来没有被调用过，logman查询当前系统中存在的provider，然后复制对应的guid是可以监听到事件的


 https://docs.microsoft.com/en-us/windows/win32/etw/fileio
 mof class fileio 
 {90cbdc39-4a3e-11d1-84f4-0000f80464e3}
//DEFINE_GUID(
//    FILE_IO_PROVIDER_GUID,
//    0x90cbdc39, 0x4a3e, 0x11d1, 0x84, 0xf4, 0x00, 0x00, 0xf8, 0x04, 0x64, 0xe3
//);

// logman query providers | findstr -i file
// EDD08927-9CC4-4E65-B970-C2560FB5C289
DEFINE_GUID(
    FILE_IO_PROVIDER_GUID,
    0xEDD08927, 0x9CC4, 0x4E65, 0xB9, 0x70, 0xC2, 0x56, 0x0F, 0xB5, 0xC2, 0x89
);

**********

微软官方文档里面mof class中的guid不能实现事件监听，consumer中的回调从来没有被调用过，logman查询当前系统中存在的provider，然后复制对应的guid是可以监听到事件的

***********

main.c

#include <stdio.h>

#include "commonDef.h"

int testController();

void testConsumer();

int main()
{
    testController();
    //testConsumer();

    return 0;
}

testController.cpp

#include <windows.h>
#include <stdio.h>
#include <conio.h>
#include <strsafe.h>
#include <wmistr.h>
#include <evntrace.h>

#include "commonDef.h"

// tracerpt.exe c:\aetw.etl -o c:\aetw.xml -of XML
// 把etl格式文件转为可读的xml文件

const GUID SessionGuid = SESSION_GUID;

const GUID FileIoProviderGuid = FILE_IO_PROVIDER_GUID;

int testController()
{
    ULONG status = ERROR_SUCCESS;
    TRACEHANDLE SessionHandle = 0;
    EVENT_TRACE_PROPERTIES* pSessionProperties = NULL;
    ULONG BufferSize = 0;
    BOOL TraceOn = TRUE;

    // Allocate memory for the session properties. The memory must
    // be large enough to include the log file name and session name,
    // which get appended to the end of the session properties structure.

    BufferSize = sizeof(EVENT_TRACE_PROPERTIES) + 2*MAX_PATH*sizeof(WCHAR);
    pSessionProperties = (EVENT_TRACE_PROPERTIES*)malloc(BufferSize);
    if (NULL == pSessionProperties)
    {
        wprintf(L"Unable to allocate %d bytes for properties structure.\n", BufferSize);
        goto cleanup;
    }

    // Set the session properties. You only append the log file name
    // to the properties structure; the StartTrace function appends
    // the session name for you.

    ZeroMemory(pSessionProperties, BufferSize);
    pSessionProperties->Wnode.BufferSize = BufferSize;
    pSessionProperties->Wnode.Flags = WNODE_FLAG_TRACED_GUID;
    pSessionProperties->Wnode.ClientContext = 1; //1:QPC clock resolution,
    pSessionProperties->Wnode.Guid = SessionGuid;
    // https://stackoverflow.com/questions/68646731/etw-realtime-consuming-of-event-trace
    pSessionProperties->LogFileMode = EVENT_TRACE_REAL_TIME_MODE;// | EVENT_TRACE_SYSTEM_LOGGER_MODE; // 
    pSessionProperties->MaximumFileSize = 1024;  // 1 MB
    pSessionProperties->FlushTimer = 1;
    // https://docs.microsoft.com/en-us/windows/win32/etw/fileio
    //pSessionProperties->EnableFlags = EVENT_TRACE_FLAG_PROCESS | EVENT_TRACE_FLAG_PROCESS_COUNTERS | EVENT_TRACE_FLAG_DISK_FILE_IO | EVENT_TRACE_FLAG_DISK_IO | EVENT_TRACE_FLAG_DISK_IO_INIT | EVENT_TRACE_FLAG_FILE_IO | EVENT_TRACE_FLAG_FILE_IO_INIT;
    pSessionProperties->LoggerNameOffset = sizeof(EVENT_TRACE_PROPERTIES);
    //pSessionProperties->LogFileNameOffset = sizeof(EVENT_TRACE_PROPERTIES) + sizeof(WCHAR)*MAX_PATH;
    wcscpy_s((WCHAR*)((char*)pSessionProperties + pSessionProperties->LoggerNameOffset), ARR_SIZE(LOGSESSION_NAME), LOGSESSION_NAME);
    //StringCbCopy((LPWSTR)((char*)pSessionProperties + pSessionProperties->LogFileNameOffset), sizeof(LOGFILE_PATH), LOGFILE_PATH);

    // Create the trace session.

    status = StartTrace(&SessionHandle, LOGSESSION_NAME, pSessionProperties);
    if (ERROR_SUCCESS != status)
    {
        wprintf(L"StartTrace() failed with %lu\n", status);
        if (status == ERROR_ALREADY_EXISTS) {
            status = ::ControlTrace(
                (TRACEHANDLE)NULL,
                LOGSESSION_NAME,
                pSessionProperties,
                EVENT_TRACE_CONTROL_STOP);

            wprintf(L"stop trace return : %d\n", status);

            if (SUCCEEDED(status)) {
                status = ::StartTrace(
                    (PTRACEHANDLE)&SessionHandle,
                    LOGSESSION_NAME,
                    pSessionProperties);
                wprintf(L"again starttrace return : %d\n", status);
            }
        }
    }

    if (ERROR_SUCCESS != status) {
        goto cleanup;
    }

    wprintf(L"StartTrace get session handle:%p\n", SessionHandle);
    // Enable the providers that you want to log events to your session.

    status = EnableTraceEx2(
        SessionHandle,
        (LPCGUID)&FileIoProviderGuid,
        EVENT_CONTROL_CODE_ENABLE_PROVIDER,
        TRACE_LEVEL_INFORMATION,
        0,
        0,
        0,
        NULL
    );

    if (ERROR_SUCCESS != status)
    {
        wprintf(L"EnableTrace() failed with %lu\n", status);
        TraceOn = FALSE;
        goto cleanup;
    }

    wprintf(L"Run the provider application. Then hit any key to stop the session.\n");
    _getch();

cleanup:

    if (SessionHandle)
    {
        if (TraceOn)
        {
            status = EnableTraceEx2(
                SessionHandle,
                (LPCGUID)&FileIoProviderGuid,
                EVENT_CONTROL_CODE_DISABLE_PROVIDER,
                TRACE_LEVEL_INFORMATION,
                0,
                0,
                0,
                NULL
            );
        }

        status = ControlTrace(SessionHandle, LOGSESSION_NAME, pSessionProperties, EVENT_TRACE_CONTROL_STOP);

        if (ERROR_SUCCESS != status)
        {
            wprintf(L"ControlTrace(stop) failed with %lu\n", status);
        }
    }

    if (pSessionProperties)
    {
        free(pSessionProperties);
        pSessionProperties = NULL;
    }

    return 0;
}

pSessionProperties->LogFileMode设置位EVENT_TRACE_REAL_TIME_MODE表示实时监听，而不是存储为文件

如上代码编译出来的程序重命名位controller.exe

consumer的实现

main.c

#include <windows.h>
#include <stdio.h>

#include "commonDef.h"

int testController();

void testConsumer();

int main()
{
    //testController();
    testConsumer();

    return 0;
}

testConsumer.cpp

#include <windows.h>
#include <stdio.h>
#include <conio.h>
#include <comutil.h>
#include <wbemidl.h>
#include <wmistr.h>
#include <evntrace.h>
#include <tdh.h>
#include <in6addr.h>

#include "commonDef.h"

#pragma comment(lib, "tdh.lib")

// Used to calculate CPU usage

ULONG g_TimerResolution = 0;

// Used to determine if the session is a private session or kernel session.
// You need to know this when accessing some members of the EVENT_TRACE.Header
// member (for example, KernelTime or UserTime).

BOOL g_bUserMode = FALSE;

// Handle to the trace file that you opened.

TRACEHANDLE g_hTrace = 0;


// Callback that receives the events. 

VOID WINAPI ProcessEvent(PEVENT_RECORD pEvent)
{
    wprintf(L"ProcessEvent:processID:%d\n", pEvent->EventHeader.ProcessId);
}

void testConsumer()
{
    TDHSTATUS status = ERROR_SUCCESS;
    EVENT_TRACE_LOGFILE trace;
    HRESULT hr = S_OK;
    TRACE_LOGFILE_HEADER* pHeader = &trace.LogfileHeader;

    // Identify the log file from which you want to consume events
    // and the callbacks used to process the events and buffers.

    ZeroMemory(&trace, sizeof(EVENT_TRACE_LOGFILE));
    trace.LogFileName = NULL;
    trace.LoggerName = (LPWSTR)LOGSESSION_NAME;
    trace.EventRecordCallback = ProcessEvent;
    trace.ProcessTraceMode = PROCESS_TRACE_MODE_EVENT_RECORD | PROCESS_TRACE_MODE_REAL_TIME;

    g_hTrace = OpenTrace(&trace);
    if (INVALID_PROCESSTRACE_HANDLE == g_hTrace)
    {
        wprintf(L"OpenTrace failed with %lu\n", GetLastError());
        goto cleanup;
    }

    //g_bUserMode = pHeader->LogFileMode & EVENT_TRACE_PRIVATE_LOGGER_MODE;

    if (pHeader->TimerResolution > 0)
    {
        g_TimerResolution = pHeader->TimerResolution / 10000;
    }

    wprintf(L"OpenTrace return:  %p\n", g_hTrace);
    wprintf(L"Number of events lost:  %lu\n", pHeader->EventsLost);

    // Use pHeader to access all fields prior to LoggerName.
    // Adjust pHeader based on the pointer size to access
    // all fields after LogFileName. This is required only if
    // you are consuming events on an architecture that is 
    // different from architecture used to write the events.

    if (pHeader->PointerSize != sizeof(PVOID))
    {
        pHeader = (PTRACE_LOGFILE_HEADER)((PUCHAR)pHeader +
            2 * (pHeader->PointerSize - sizeof(PVOID)));
    }

    wprintf(L"Number of buffers lost: %lu\n\n", pHeader->BuffersLost);

    // https://docs.microsoft.com/en-us/windows/win32/api/evntrace/nf-evntrace-processtrace
    // This function blocks until processing ends
    status = ProcessTrace(&g_hTrace, 1, 0, 0);
    if (status != ERROR_SUCCESS && status != ERROR_CANCELLED)
    {
        wprintf(L"ProcessTrace failed with %lu\n", status);
        goto cleanup;
    }

    wprintf(L"ProcessTrace return: %lu, press any key to quit\n\n", status);
    _getch();

cleanup:

    if (INVALID_PROCESSTRACE_HANDLE != g_hTrace)
    {
        status = CloseTrace(g_hTrace);
    }
}

一个程序实现controller和consumer，但是编译后重命名程序位controller.exe和consumer.exe，先运行controller.exe打开控制器，然后运行consumer.exe订阅事件

注意事项

1. pSessionProperties->LogFileMode = EVENT_TRACE_REAL_TIME_MODE;表示实时监控，如果不是实时监控，需要设置LogFileNameOffset，并且将文件路径复制到Offset对应的位置
2. pSessionProperties->Wnode.Guid = SessionGuid;表示自己的控制器对应的guid，如果重复打开会报错183
3. StartTrace的第二个参数是session的名字，consumer会根据这个loggerName打开Trace，如上图中的名字
4. consumer中的trace.LoggerName = (LPWSTR)LOGSESSION_NAME;要和controller总设置的一样
5. trace.ProcessTraceMode = PROCESS_TRACE_MODE_EVENT_RECORD | PROCESS_TRACE_MODE_REAL_TIME;表示实时记录，要与controller中一样
6. 执行ProcessTrace之后，如果成功，该线程会阻塞，知道controller结束或者BufferCallback返回false
7. 微软官方提供的etw文档里面又mof class的guid，但是如果controller中直接使用该guid，consumer中调用ProcessTrace后就只是卡住，没有ProcessEvent的任何打印。通过logman查询到provider对应的guid是有ProcessEvent的打印的

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