用于加密/解密的Firebird数据库UDF未释放内存 我在FielBoe3数据库中测试一个UDF外部函数，我使用一个给定的键，对一个给定的字符串执行了一个简单的XOR C++。

代码如下：

#include <windows.h>
#include <iostream>
#include <string>
#include <stdio.h>
#include <vector>
#include <math.h>

#include "../FirebirdLib/src/include/ibase.h"
#include "ib_util.h"


using namespace std;

//------------------------------------------------------------------------------------
typedef void (__stdcall * FCallback)(const char * message);
FCallback g_messageCallback = 0;
FCallback g_errorCallback = 0;
//------------------------------------------------------------------------------------
#define ON_MESSAGE(mess) { if(g_messageCallback) g_messageCallback(mess); }
#define ON_ERROR(mess) { if(g_errorCallback) g_errorCallback(mess); }
//------------------------------------------------------------------------------------
extern "C" __declspec(dllexport) void RegisterCallbacks(FCallback messageCallback, FCallback errorCallback)
{
    g_messageCallback = messageCallback;
    g_errorCallback = errorCallback;
}
//------------------------------------------------------------------------------------
class EncryptionUDF
{
public:
    EncryptionUDF()
    {

        //ON_MESSAGE("--EncryptionUDF created--")
    }
    ~EncryptionUDF()
    {
        //ON_MESSAGE("--EncryptionUDF destroyed--")
    }

    char* XORCipher(const char* data, const char* key, int dataLen, int keyLen) {
        char* output = (char*)ib_util_malloc(2000 + 1L);
        output[dataLen] = '\0';
        for (int i = 0; i < dataLen; ++i) {
            if (data[i] != key[i % keyLen])
                output[i] = data[i] ^ key[i % keyLen];
            else 
                output[i] = data[i];
        }       

        return output;
    }

    char * Encrypt(const char * str, const char * key) {
        int dataLen = strlen(str);
        int keyLen = strlen(key);
        char* output = (char*)ib_util_malloc(2000 + 1L);
        output[dataLen] = '\0';

        try {
            if ((str == NULL) || (str[0] == '\0')) {
                return NULL;
            }
            else {
                try {
                    if ((key != NULL) && (key[0] == '\0')) {
                        strncpy(output, str, dataLen);
                    }
                    else if (key != NULL) {
                        output = XORCipher(str, key, dataLen, keyLen);
                    }
                    else strncpy(output, str, dataLen);
                }
                catch (...) { strncpy(output, str, dataLen); }

                return output;
            }
        }
        catch (...) { strncpy(output, str, dataLen); }

        return output;
    }

    char * Decrypt(const char * str, const char * key) {
        int dataLen = strlen(str);
        int keyLen = strlen(key);
        char* output = (char*)ib_util_malloc(2000 + 1L);
        output[dataLen] = '\0';

        try {
            if ((str == NULL) || (str[0] == '\0')) {
                return NULL;
            }
            else {
                try {
                    if ((key != NULL) && (key[0] == '\0')) {
                        strncpy(output, str, dataLen);
                    }
                    else if (key != NULL) {
                        output = XORCipher(str, key, dataLen, keyLen);
                    }
                    else strncpy(output, str, dataLen);
                }
                catch (...) { strncpy(output, str, dataLen); }

                return output;
            }
        }
        catch (...) { strncpy(output, str, dataLen); }

        return output;
    }
};
//------------------------------------------------------------------------------------
extern "C" __declspec(dllexport) char * EncryptUDF_DesEncrypt(const char *str, const char *key)
{
    try
    {
        EncryptionUDF self = EncryptionUDF();
        return self.Encrypt(str, key);
    }
    catch (std::exception & ex)
    {
        ON_ERROR(ex.what());
    }
    catch (...)
    {
        ON_ERROR("Unknown error");
    }
    return 0;
}
//------------------------------------------------------------------------------------
extern "C" __declspec(dllexport) char * EncryptUDF_DesDecrypt(const char *str, const char *key)
{
    try
    {
        EncryptionUDF self = EncryptionUDF();
        return self.Decrypt(str, key);
    }
    catch (std::exception & ex)
    {
        ON_ERROR(ex.what());
    }
    catch (...)
    {
        ON_ERROR("Unknown error");
    }
    return 0;
}
//------------------------------------------------------------------------------------
BOOL APIENTRY DllMain( HMODULE hModule,
                      DWORD  ul_reason_for_call,
                      LPVOID lpReserved
                      )
{
    return TRUE;
}
//------------------------------------------------------------------------------------

在SQL select命令中使用此UDF时，firebird server使用的ram会不断增加。当使用嵌入式系统时，RAM会快速上升，当处于服务器模式时，RAM会逐渐增加，但速度较慢，而且更容易控制

---

请帮助理解错误所在。

经过一些调查，我决定使用以下方法更改代码中复制字符串的部分：

strncpy(output, str, dataLen);

与：

在这一更改之后，内存一直处于正常水平，无论是嵌入式firebird还是服务器模式

这似乎是释放或管理这些字符串副本时的内存泄漏

strncpy(output, str, dataLen);

strncpy_s(output, dataLen, str, dataLen);