访问被拒绝修改现有的符号链接目标

Question

简而言之，我尝试使用Visual C ++以编程方式修改现有的NTFS符号链接目标。在此代码段中，我实际上并未对链接执行任何操作。为简单起见，我只是将结构读入缓冲区，然后将该缓冲区写回自身。我在第二次ERROR_ACCESS_DENIED来电时收到DeviceIoControl。在我看来，手柄正在打开具有完全权限的链接，所以我很困惑，一定有别的东西我做错了吗？

#include "stdafx.h"
#include <stdio.h>
#include <ole2.h>

typedef struct _REPARSE_DATA_BUFFER {
    ULONG  ReparseTag;
    USHORT  ReparseDataLength;
    USHORT  Reserved;
    union {
        struct {
            USHORT SubstituteNameOffset;
            USHORT SubstituteNameLength;
            USHORT PrintNameOffset;
            USHORT PrintNameLength;
            ULONG Flags;
            WCHAR PathBuffer[1];
        } SymbolicLinkReparseBuffer;
        struct {
            USHORT SubstituteNameOffset;
            USHORT SubstituteNameLength;
            USHORT PrintNameOffset;
            USHORT PrintNameLength;
            WCHAR PathBuffer[1];
        } MountPointReparseBuffer;
        struct {
            UCHAR DataBuffer[1];
        } GenericReparseBuffer;
    };
} REPARSE_DATA_BUFFER;

#define REPARSE_MOUNTPOINT_HEADER_SIZE   8

int _tmain(int argc, _TCHAR* argv[])
{
    HANDLE hFile;
    LPCTSTR szMyFile = _T("C:\\Users\\Weston\\Desktop\\New folder\\SymbolicLink of test.txt");

    hFile = CreateFile(szMyFile, GENERIC_ALL, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, NULL);
    if (hFile == INVALID_HANDLE_VALUE)
    {
        _tprintf(_T("Could not open dir '%s'; error: %d\n"), szMyFile, GetLastError());
        CloseHandle(hFile);
        return 1;
    }

    REPARSE_DATA_BUFFER* rdata = (REPARSE_DATA_BUFFER*)malloc(MAXIMUM_REPARSE_DATA_BUFFER_SIZE);

    DWORD dwRetLen = 0;
    BOOL bRet = DeviceIoControl(hFile, FSCTL_GET_REPARSE_POINT, NULL, 0, rdata, MAXIMUM_REPARSE_DATA_BUFFER_SIZE, &dwRetLen, NULL);
    if (bRet == FALSE)
    {
        _tprintf(_T("DeviceIoControl1 failed with error: %d\n"), GetLastError());

        CloseHandle(hFile);
        return 1;
    }

    DWORD ioctl_return = 0xdeadbeef;
    if (!DeviceIoControl(hFile,
        FSCTL_SET_REPARSE_POINT,
        rdata,
        REPARSE_MOUNTPOINT_HEADER_SIZE + rdata->ReparseDataLength,
        NULL,
        0,
        &ioctl_return,
        NULL)) {
        _tprintf(_T("DeviceIoControl2 failed with error: %d\n"), GetLastError());
        CloseHandle(hFile);
        return 1;
    }

    CloseHandle(hFile);
    return 0;
}