c++ - windows EnumProcesses 一些进程名称为

Question

你好我有this运行示例代码，它使用 x 打印所有当前正在运行的进程的进程名称和 PIDS。不过，其中只有一些显示真实名称，其他显示为(如下面的输出图像所示)

我想知道这是否是预期的行为，并且并非所有进程都有名称(我可以看到这是最小后台进程的情况)，或者我是否错误地使用了 EnumProcesses 函数。

我的代码是:

#include <windows.h>
#include <stdio.h>
#include <tchar.h>
#include <psapi.h>
#include <tlhelp32.h>
#include <tchar.h>


//https://learn.microsoft.com/en-us/windows/desktop/psapi/enumerating-all-processes
void PrintProcessNameAndID( DWORD processID ){
    TCHAR szProcessName[MAX_PATH] = TEXT("<unknown>");
    // Get a handle to the process.
    HANDLE hProcess = OpenProcess( PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, processID );
    // Get the process name.
    if (NULL != hProcess ){
        HMODULE hMod;
        DWORD cbNeeded;
        if ( EnumProcessModules( hProcess, &hMod, sizeof(hMod), &cbNeeded) ){
            GetModuleBaseName( hProcess, hMod, szProcessName, sizeof(szProcessName)/sizeof(TCHAR) );
        }
    }
    // Print the process name and identifier.
    _tprintf( TEXT("%s  (PID: %u)\n"), szProcessName, processID );
    // Release the handle to the process.
    CloseHandle( hProcess );
}

//https://learn.microsoft.com/en-us/windows/desktop/psapi/enumerating-all-processes
int main( void ){
    // Get the list of process identifiers.
    DWORD aProcesses[1024], cbNeeded, cProcesses;
    unsigned int i;
    if ( !EnumProcesses( aProcesses, sizeof(aProcesses), &cbNeeded ) ){
        return 1;
    }
    // Calculate how many process identifiers were returned.
    cProcesses = cbNeeded / sizeof(DWORD);
    // Print the name and process identifier for each process.
    //for ( i = 0; i < cProcesses; i++ ){
    for ( i = 0; i < 3; i++ ){
        if( aProcesses[i] != 0 )        {
            _tprintf( TEXT("aProcesses[%u] = %u (process ID)\n"), i, aProcesses[i] );
            PrintProcessNameAndID( aProcesses[i] );
            ListProcessThreads( aProcesses[i] );
        }
    }
    return 0;
}

Answer 1

如 documentation 中所述, OpenProcess 对空闲和 CSRSS 进程失败。

If the specified process is the Idle process or one of the CSRSS processes, this function fails and the last error code is ERROR_ACCESS_DENIED because their access restrictions prevent user-level code from opening them.

您必须启用 SeDebugPrivilege(并且还要以管理员权限运行您的应用程序)。此外，如果您的应用程序编译为 32 位，则它无法使用 OpenProcess

访问 64 位进程

如果您只想要一个正在运行的进程列表，请使用 CreateToolhelp32Snapshot 列出正在运行的进程。

#define UNICODE
#include <Windows.h>
#include <stdio.h>
#include <psapi.h>
#include <tlhelp32.h>

int main()
{
    wprintf(L"Start:\n");
    HANDLE hndl = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS | TH32CS_SNAPMODULE, 0);
    if(hndl)
    {
        PROCESSENTRY32  process = { sizeof(PROCESSENTRY32) };
        Process32First(hndl, &process);
        do
        {
            wprintf(L"%8u, %s\n", process.th32ProcessID, process.szExeFile);
        } while(Process32Next(hndl, &process));

        CloseHandle(hndl);
    }
}

旁注，建议将程序编译为 Unicode。避免 _txxx 宏，例如 _tprintf 等