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Windows 9x/2000 跨平台創建共享目錄：動態加載 NetShareAdd 實現

編輯：VC 教學

背景：API 依賴差異導致的兼容性難題

創建共享目錄需調用 NetShareAdd，但其所在 DLL 不同：

Windows 2000/NT：Netapi32.dll
Windows 9x：Svrapi.dll

靜態鏈接對應 .lib 會導致在另一平台啟動失敗（缺少 DLL/導出函數）。解決方案：運行時動態加載 DLL，獲取函數指針調用。

完整跨平台實現代碼

1. 類型定義與常量

// 函數指針類型
typedef DWORD (WINAPI *NETSHAREADD2K)(LPWSTR, DWORD, LPBYTE, LPDWORD); // NT/2K: Unicode, Level 2
typedef DWORD (WINAPI *NETSHAREADD9X)(const char FAR*, short, const char FAR*, unsigned short); // 9x: ANSI, Level 50

NETSHAREADD2K pNetShareAdd2k = NULL;
NETSHAREADD9X pNetShareAdd9x = NULL;
bool bWinNT = false;
HINSTANCE hDll = NULL;

// 常量
#define NNLEN 80
#define LM20_NNLEN 12
#define SHPWLEN 8
#define STYPE_DISKTREE 0
#define SHI50F_FULL 0x0002
#define NERR_Success 0
#define NERR_BASE 2100
#define NERR_DuplicateShare (NERR_BASE + 18)
#define NERR_RedirectedPath (NERR_BASE + 17)
#define NERR_UnknownDevDir (NERR_BASE + 16)

// 9x 結構 (Level 50)
struct share_info_50 {
    char shi50_netname[LM20_NNLEN + 1];
    unsigned char shi50_type;
    unsigned short shi50_flags;
    char FAR *shi50_remark;
    char FAR *shi50_path;
    char shi50_rw_password[SHPWLEN + 1];
    char shi50_ro_password[SHPWLEN + 1];
};

// 2K 結構 (Level 2)
struct SHARE_INFO_2 {
    LPWSTR shi2_netname;
    DWORD shi2_type;
    LPWSTR shi2_remark;
    DWORD shi2_permissions;
    DWORD shi2_max_uses;
    DWORD shi2_current_uses;
    LPWSTR shi2_path;
    LPWSTR shi2_passwd;
};

2. 初始化：檢測系統並加載對應 DLL

bool __fastcall InitApi() {
    OSVERSIONINFO info = { sizeof(info) };
    GetVersionEx(&info);
    bWinNT = (info.dwPlatformId == VER_PLATFORM_WIN32_NT);

    if (bWinNT) {
        hDll = LoadLibrary("Netapi32.dll");
        if (hDll) pNetShareAdd2k = (NETSHAREADD2K)GetProcAddress(hDll, "NetShareAdd");
    } else {
        hDll = LoadLibrary("Svrapi.dll");
        if (hDll) pNetShareAdd9x = (NETSHAREADD9X)GetProcAddress(hDll, "NetShareAdd");
    }
    return (bWinNT ? pNetShareAdd2k : pNetShareAdd9x) != NULL;
}

3. 統一調用接口：MyPathToNetShare

String __fastcall MyPathToNetShare(String strPath, String strNetName,
    String strPassword, String strRemark) {

    if (!InitApi()) return "函數獲取錯誤!";

    if (!bWinNT) { // Windows 9x
        share_info_50 *pBuf = (share_info_50*)malloc(sizeof(share_info_50));
        if (!pBuf) return "內存分配失敗!";

        strcpy(pBuf->shi50_netname, strNetName.c_str());
        pBuf->shi50_type = STYPE_DISKTREE;
        pBuf->shi50_flags = SHI50F_FULL;
        pBuf->shi50_remark = strRemark.c_str();
        pBuf->shi50_path = strPath.c_str();
        strcpy(pBuf->shi50_rw_password, strPassword.c_str());
        strcpy(pBuf->shi50_ro_password, strPassword.c_str());

        DWORD nStatus = pNetShareAdd9x(NULL, 50, (char FAR*)pBuf, sizeof(share_info_50));
        free(pBuf);
        FreeLibrary(hDll);

        return (nStatus == NERR_Success) ? "添加成功!" : "錯誤碼: " + String(nStatus);
    }
    else { // Windows 2000/NT
        // 提升權限（需要 SE_SECURITY_PRIVILEGE 或管理員）
        HANDLE hToken;
        TOKEN_PRIVILEGES tk;
        OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &hToken);
        LookupPrivilegeValue(NULL, SE_SECURITY_NAME, &tk.Privileges[0].Luid); // 注意：原代碼用 SE_SHUTDOWN_NAME 可能不夠
        tk.PrivilegeCount = 1;
        tk.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
        AdjustTokenPrivileges(hToken, FALSE, &tk, 0, NULL, 0);

        SHARE_INFO_2 si2 = {0};
        si2.shi2_path = StringToOleStr(strPath);
        si2.shi2_remark = StringToOleStr(strRemark);
        si2.shi2_netname = StringToOleStr(strNetName);
        si2.shi2_passwd = StringToOleStr(strPassword);
        si2.shi2_type = STYPE_DISKTREE;
        si2.shi2_permissions = 0; // ACCESS_READ | ACCESS_WRITE...
        si2.shi2_max_uses = -1;
        si2.shi2_current_uses = 0;

        DWORD dwParamErr;
        DWORD nas = pNetShareAdd2k(NULL, 2, (LPBYTE)&si2, &dwParamErr);
        FreeLibrary(hDll);

        switch (nas) {
            case NERR_Success: return "設置成功!";
            case ERROR_ACCESS_DENIED: return "拒絕訪問! (需管理員權限)";
            case NERR_DuplicateShare: return "共享名已存在!";
            case NERR_UnknownDevDir: return "路徑不存在!";
            default: return "未知錯誤: " + String(nas);
        }
    }
}

4. 調用示例

void __fastcall TForm1::Button1Click(TObject *Sender) {
    ShowMessage(MyPathToNetShare("C:\\ShareDir", "MyShare", "", "共享說明"));
}

關鍵技術點總結

動態加載：LoadLibrary + GetProcAddress 解決平台差異，核心技巧。
字符集處理：9x 用 ANSI (char*)，2K 用 Unicode (LPWSTR)，StringToOleStr (SysAllocString) 轉換 BSTR，用完需 SysFreeString（此處簡化未釋放，生產代碼必須釋放）。
結構體對齊：#pragma pack(push, 1) 確保與系統定義一致，防止參數錯位。
權限提升：NT 系列創建共享需管理員權限，代碼演示了 Token 權限調整（建議使用清單 requireAdministrator 或檢查權限）。
錯誤碼映射：將系統錯誤碼轉為友好提示，提升用戶體驗。