"创建一个不是创建进程子进程的新进程"

Question

I am developing an application in which a number of instances of a process, A, depend on a single instance of a process, B. The idea is that one of the instances of process A starts process B so that all the instances of A can use it. The instances of A are hosted in a 3rd party process and can be torn down (by killing the process tree) at unpredictable points in time. It is therefore vital that process B is not a child of any instance of process A.

[DllImport("kernel32.dll")]
private static extern bool CreateProcess(string lpApplicationName, string lpCommandLine, IntPtr lpProcessAttributes, IntPtr lpThreadAttributes, bool bInheritHandles, uint dwCreationFlags, IntPtr lpEnvironment, string lpCurrentDirectory, [In] ref StartupInfo lpStartupInfo, out ProcessInformation lpProcessInformation);


public Process LaunchProcess(Path executablePath, string args)
{
    StartupInfo sInfo = new StartupInfo();

    const uint creationFlags = (uint)(CreationFlags.CreateNoWindow | CreationFlags.DetachedProcess);

    ProcessInformation pInfo;
    bool success = CreateProcess(executablePath.ToString(), args, IntPtr.Zero, IntPtr.Zero, false, creationFlags, IntPtr.Zero, executablePath.GetFolderPath().ToString(), ref sInfo, out pInfo);

    if (!success)
    {
        throw new Win32Exception();
    }

    return Process.GetProcessById(pInfo.dwProcessId);
}

Answer 1

You can try to use the ManagementClass to launch a process and pass some CreateFlags , more specifically, the DETACHED_PROCESS flag. (You'll need to reference System.Management .)

private static void Main()
{
    using (var managementClass = new ManagementClass("Win32_Process"))
    {
        var processInfo = new ManagementClass("Win32_ProcessStartup");
        processInfo.Properties["CreateFlags"].Value = 0x00000008;

        var inParameters = managementClass.GetMethodParameters("Create");
        inParameters["CommandLine"] = "notepad.exe";
        inParameters["ProcessStartupInformation"] = processInfo;

        var result = managementClass.InvokeMethod("Create", inParameters, null);
        if ((result != null) && ((uint)result.Properties["ReturnValue"].Value != 0))
        {
            Console.WriteLine("Process ID: {0}", result.Properties["ProcessId"].Value);
        }
    }

    Console.ReadKey();
}

At least on my machine notepad is not considered a child process of my console test application.

Answer 2

You can specify a different parent by using a process attribute. Here is a function that does just that.

bool CreateProcessWithParent(DWORD parentId, PWSTR commandline) {
    auto hProcess = ::OpenProcess(PROCESS_CREATE_PROCESS, FALSE, parentId);
    if (!hProcess)
        return false;
 
    SIZE_T size;
    //
    // call InitializeProcThreadAttributeList twice
    // first, get required size
    //
    ::InitializeProcThreadAttributeList(nullptr, 1, 0, &size);
 
    //
    // now allocate a buffer with the required size and call again
    //
    auto buffer = std::make_unique<BYTE[]>(size);
    auto attributes = reinterpret_cast<PPROC_THREAD_ATTRIBUTE_LIST>(buffer.get());
    ::InitializeProcThreadAttributeList(attributes, 1, 0, &size);
 
    //
    // add the parent attribute
    //
    ::UpdateProcThreadAttribute(attributes, 0, 
        PROC_THREAD_ATTRIBUTE_PARENT_PROCESS, 
        &hProcess, sizeof(hProcess), nullptr, nullptr);
 
    STARTUPINFOEX si = { sizeof(si) };
    //
    // set the attribute list
    //
    si.lpAttributeList = attributes;
    PROCESS_INFORMATION pi;
 
    //
    // create the process
    //
    BOOL created = ::CreateProcess(nullptr, commandline, nullptr, nullptr, 
        FALSE, EXTENDED_STARTUPINFO_PRESENT, nullptr, nullptr, 
        (STARTUPINFO*)&si, &pi);
 
    //
    // cleanup
    //
    ::CloseHandle(hProcess);
    ::DeleteProcThreadAttributeList(attributes);
 
    return created;
}