c# - 将字符串从 c# 传递到 c dll 时的错误行为

Question

我对我的问题进行了很多研究，发现了许多与[如何从c#传递字符串]相关的问题。至c dll]:

• Passing strings from C# to C++ DLL and back -- minimal example

• https://www.codeproject.com/Articles/1189085/%2FArticles%2F1189085%2FPassing-strings-between-managed-and-unmanaged-code

但是他们都帮不了我。我喜欢以任何方式提出问题:

<小时/>

简要说明:
我的c功能在 c# 中正常工作就在我交换GetProcessIntegrityLevel时参数(在 c dll 和 c# import-dll 中)来自:

1. BOOL GetProcessIntegrityLevel(DWORD dwPID, LPSTR szIntegrityLevel);

对于这个:

BOOL GetProcessIntegrityLevel(LPSTR szIntegrityLevel, DWORD dwPID);

在第一种状态下，我的程序正常工作并更改了 LPSTR szIntegrityLevel但在第二，它不起作用并且 LPSTR szIntegrityLevel对于任何 pid 都始终为空。

<小时/>

我创建了一个 c我在其中声明了以下内容 c获取 Integrity Level 的函数 通过 pid 的进程:

#define         MAX_INTEGRITY_LEVEL_LENGTH                  30
extern "C"
{
    __declspec(dllexport) BOOL GetProcessIntegrityLevel(DWORD dwPID, LPSTR szIntegrityLevel);
}

C 函数实现:

BOOL GetProcessIntegrityLevel(DWORD dwPID, LPSTR szIntegrityLevel)
{
    BOOL    bFlag = FALSE;                      // Return flag
    HANDLE  hToken = INVALID_HANDLE_VALUE;      // Token handle
    HANDLE  hProcess = NULL;                    // Process handle
    BOOL    bProcToken = FALSE;                 // OpenProcessToken() result
    BOOL    bTokenInfo = FALSE;                 // GetTokenInformation() result
    DWORD   dwLengthNeeded = 0;                 // Token information length
    DWORD   dwError = ERROR_SUCCESS;            // GetTokenInformation() last error
    DWORD   dwIntegrityLevel = 0;               // Integrity level

    PTOKEN_MANDATORY_LABEL pTIL = NULL;         // Use as token information

    // Open the process
    hProcess = OpenProcess(MAXIMUM_ALLOWED | PROCESS_QUERY_LIMITED_INFORMATION,
        FALSE, dwPID);
    if (hProcess != NULL)
    {
        // Open process token
        bProcToken = OpenProcessToken(hProcess, TOKEN_QUERY, &hToken);
        if (bProcToken == TRUE)
        {
            // Get token information
            bTokenInfo = GetTokenInformation(hToken, TokenIntegrityLevel,
                NULL, 0, &dwLengthNeeded);
            if (bTokenInfo == FALSE)
            {
                dwError = GetLastError();
                if (dwError == ERROR_INSUFFICIENT_BUFFER)
                {
                    pTIL = (PTOKEN_MANDATORY_LABEL)LocalAlloc(0, dwLengthNeeded);
                    if (pTIL != NULL)
                    {
                        // Get token information
                        bTokenInfo = GetTokenInformation(hToken, TokenIntegrityLevel,
                            pTIL, dwLengthNeeded, &dwLengthNeeded);
                        if (bTokenInfo == TRUE)
                        {
                            // Get integrity level
                            dwIntegrityLevel = *GetSidSubAuthority(pTIL->Label.Sid,
                                (DWORD)(UCHAR)(*GetSidSubAuthorityCount(pTIL->Label.Sid) - 1));

                            if (dwIntegrityLevel <= SECURITY_MANDATORY_LOW_RID)
                            {
                                // Low Integrity
                                StrCpyA(szIntegrityLevel, "Low");
                            }
                            else if ((dwIntegrityLevel >= SECURITY_MANDATORY_MEDIUM_RID) &&
                                (dwIntegrityLevel < SECURITY_MANDATORY_HIGH_RID))
                            {
                                // Medium Integrity
                                StrCpyA(szIntegrityLevel, "Medium");
                            }
                            else if ((dwIntegrityLevel >= SECURITY_MANDATORY_HIGH_RID) &&
                                (dwIntegrityLevel < SECURITY_MANDATORY_SYSTEM_RID))
                            {
                                // High Integrity
                                StrCpyA(szIntegrityLevel, "High");
                            }
                            else if (dwIntegrityLevel >= SECURITY_MANDATORY_SYSTEM_RID)
                            {
                                // System Integrity
                                StrCpyA(szIntegrityLevel, "System");
                            }
                            else if (dwIntegrityLevel == SECURITY_MANDATORY_UNTRUSTED_RID)
                            {
                                // Untrusted integrity
                                StrCpyA(szIntegrityLevel, "Untrusted");
                            }
                            else
                            {
                                StrCpyA(szIntegrityLevel, "UnKnown");
                            }

                            bFlag = TRUE;
                        }

                        LocalFree(pTIL);
                    }
                }
            }

            // Close token handle
            CloseHandle(hToken);
        }

        // Close the process handle
        CloseHandle(hProcess);
    }

    return bFlag;
}

所以，我导入 GetProcessIntegrityLevel()来 self 的c dll 在 c#如下:

// Define function pointers for using of c dll functions
[DllImport("ProcessesPropDll.dll",CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]
[return: MarshalAs(UnmanagedType.Bool)]
// Get integrity level
static extern bool GetProcessIntegrityLevel(ulong dwPID, StringBuilder szIntegrityLevel);

并调用c#中的函数像这样:

// Integrity level
StringBuilder integrityLevel = new StringBuilder(200);

if(GetProcessIntegrityLevel(11684, integrityLevel) == true)
{
      MessageBox.Show(integrityLevel.ToString());
}

在这种状态下，当我运行程序时，GetProcessIntegrityLevel()返回true但是integrityLevel对于任何pid，消息框中始终为空!!!

‌令人惊讶的是，当我交换 c 中的参数时函数，也在c#中，它确实有效:

__declspec(dllexport) BOOL GetProcessIntegrityLevel(LPSTR szIntegrityLevel, DWORD dwPID);

这对我来说很奇怪。我还尝试过 MarshalAs(UnmanagedType.LPStr)]但给我相同的结果。

Answer 1

在 C# 中，ulong 是 64 位类型。 PID 参数是 DWORD，它是一个 32 位参数。

将 C# 参数声明从 ulong 更改为 uint 以解决问题。