c# - PInvoke NetLocalGroupGetMembers 遇到 FatalExecutionEngineError

Question

我需要在 C# 中使用 win32 NetLocalGroupGetMembers。我找到并测试了三种解决方案。这三个都因 FatalExecutionEngineError 而失败。框架是.net 4.0

这是一个完整的例子:

API 引用:

static class NetworkAPI
{
    [DllImport("Netapi32.dll")]
    public extern static int NetLocalGroupGetMembers([MarshalAs(UnmanagedType.LPWStr)] string servername, [MarshalAs(UnmanagedType.LPWStr)] string localgroupname, int level, out IntPtr bufptr, int prefmaxlen, out int entriesread, out int totalentries, out int resumehandle);

    [DllImport("Netapi32.dll")]
    public extern static int NetApiBufferFree(IntPtr Buffer);

    // LOCALGROUP_MEMBERS_INFO_1 - Structure for holding members details
    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
    public struct LOCALGROUP_MEMBERS_INFO_1
    {
        public int lgrmi1_sid;
        public int lgrmi1_sidusage;
        public string lgrmi1_name;
    }
}

调用函数:

static void Main(string[] args)
{
    int EntriesRead;
    int TotalEntries;
    int Resume;
    IntPtr bufPtr;

    string groupName = "Administrators";

    NetworkAPI.NetLocalGroupGetMembers(null, groupName, 1, out bufPtr, -1, out EntriesRead, out TotalEntries, out Resume);

    if (EntriesRead > 0)
    {
        NetworkAPI.LOCALGROUP_MEMBERS_INFO_1[] Members = new NetworkAPI.LOCALGROUP_MEMBERS_INFO_1[EntriesRead];
        IntPtr iter = bufPtr;

        // EntriesRead has the correct quantity of members of the group, so the group is found
        for (int i = 0; i < EntriesRead; i++)
        {
            // --------------------------------------------------
            // ==> here the FatalExecutionEngineError happens:
            Members[i] = (NetworkAPI.LOCALGROUP_MEMBERS_INFO_1)Marshal.PtrToStructure(iter, typeof(NetworkAPI.LOCALGROUP_MEMBERS_INFO_1));
            //
            // --------------------------------------------------

            iter = (IntPtr)((int)iter + Marshal.SizeOf(typeof(NetworkAPI.LOCALGROUP_MEMBERS_INFO_1)));
            Console.WriteLine(Members[i].lgrmi1_name);
        }
        NetworkAPI.NetApiBufferFree(bufPtr);
    }
}

Answer 1

我看到以下错误:

1. 恢复句柄是一个指针。对该参数使用 ref IntPtr resumehandle，并在第一次调用时传递 IntPtr.Zero。或者，如果您不需要使用恢复句柄，则将参数声明为 IntPtr resumehandle 并传递 IntPtr.Zero。有关完整详细信息，请参阅 MSDN 上的功能文档。
2. 结构的lgrmi1_sid 成员是一个指针。声明如下:public IntPtr lgrmi1_sid。
3. 将 IntPtr 转换为 int 将导致指针在 64 位上被截断。直接在 IntPtr 上使用算术，或者对于旧的 C# 版本转换为 long。前者更好，如下所示:iter += Marshal.SizeOf(typeof(NetworkAPI.LOCALGROUP_MEMBERS_INFO_1));。
4. 您不检查返回值是否有错误。

修复这些错误，您的程序将正确运行。