DeviceIoControl Неверный доступ к ячейке памяти

Я получаю неверный доступ к памяти, когда я запускаю следующий код

WIN32_FIND_DATAW FD;
WCHAR cPath[MAX_PATH], cFindPath[MAX_PATH];

if (!GetCurrentDirectoryW(MAX_PATH, cPath))
ErrorExit("GetCurrentDirectory");
else
printf("Current Path: %s\n", cPath);

StringCchCopyW(cFindPath, MAX_PATH, cPath);
StringCchCatW(cFindPath, MAX_PATH, L"\\*");

BOOL bsuccess;

HANDLE hFind = FindFirstFileW(cFindPath, &FD);

if (INVALID_HANDLE_VALUE != hFind)
{
vector<wstring> links;
do
{
WCHAR  fullFileName[MAX_PATH];
StringCchPrintfW(fullFileName, MAX_PATH, L"\\\\?\\%s\\%s", cPath, FD.cFileName);

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

DWORD bytesReturned;
HANDLE hFile = CreateFileW(fullFileName, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL, OPEN_EXISTING, FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS, NULL);
if (INVALID_HANDLE_VALUE != hFile)
{
if (DeviceIoControl(hFile, FSCTL_GET_REPARSE_POINT, NULL, 0, &rdata, dwBufSize, &bytesReturned, NULL))
{
if (IsReparseTagMicrosoft(rdata->ReparseTag))
{

if (rdata->ReparseTag == IO_REPARSE_TAG_SYMLINK)
{
printf("Symbolic-Link\n");
size_t slen = rdata->SymbolicLinkReparseBuffer.SubstituteNameLength / sizeof(WCHAR);
WCHAR *szSubName = new WCHAR[slen + 1];
wcsncpy_s(szSubName, slen + 1, &rdata->SymbolicLinkReparseBuffer.PathBuffer[rdata->SymbolicLinkReparseBuffer.SubstituteNameOffset / sizeof(WCHAR)], slen);
szSubName[slen] = 0;
printf("SubstitutionName (len: %d): '%S'\n", rdata->SymbolicLinkReparseBuffer.SubstituteNameLength, szSubName);
delete[] szSubName;

size_t plen = rdata->SymbolicLinkReparseBuffer.PrintNameLength / sizeof(WCHAR);
WCHAR *szPrintName = new WCHAR[plen + 1];
wcsncpy_s(szPrintName, plen + 1, &rdata->SymbolicLinkReparseBuffer.PathBuffer[rdata->SymbolicLinkReparseBuffer.PrintNameOffset / sizeof(WCHAR)], plen);
szPrintName[plen] = 0;
printf("PrintName (len: %d): '%S'\n", rdata->SymbolicLinkReparseBuffer.PrintNameLength, szPrintName);
delete[] szPrintName;
}
else if (rdata->ReparseTag == IO_REPARSE_TAG_MOUNT_POINT)
{
printf("Mount-Point\n");
size_t slen = rdata->MountPointReparseBuffer.SubstituteNameLength / sizeof(WCHAR);
WCHAR *szSubName = new WCHAR[slen + 1];
wcsncpy_s(szSubName, slen + 1, &rdata->MountPointReparseBuffer.PathBuffer[rdata->MountPointReparseBuffer.SubstituteNameOffset / sizeof(WCHAR)], slen);
szSubName[slen] = 0;
printf("SubstitutionName (len: %d): '%S'\n", rdata->MountPointReparseBuffer.SubstituteNameLength, szSubName);
delete[] szSubName;

size_t plen = rdata->MountPointReparseBuffer.PrintNameLength / sizeof(WCHAR);
WCHAR *szPrintName = new WCHAR[plen + 1];
wcsncpy_s(szPrintName, plen + 1, &rdata->MountPointReparseBuffer.PathBuffer[rdata->MountPointReparseBuffer.PrintNameOffset / sizeof(WCHAR)], plen);
szPrintName[plen] = 0;
printf("PrintName (len: %d): '%S'\n", rdata->MountPointReparseBuffer.PrintNameLength, szPrintName);
delete[] szPrintName;
}
else
{
printf("No Mount-Point or Symblic-Link...\n");
}
}
else
{
printf("Not a Microsoft-reparse point - could not query data!\n");
}
free(rdata);
}
else
ErrorExit("DeviceIoControl");
}

CloseHandle(hFile);} while (FindNextFileW(hFind, &FD));
}
else
ErrorExit("FindFirstFile");

но следующий код работает нормально.

HANDLE hFile;
LPCTSTR szMyFile = ("C:\\Documents and Settings");  // Mount-Point (JUNCTION)
//LPCTSTR szMyFile = _T("C:\\Users\\All Users");  // Symbolic-Link (SYMLINKD)

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

// Allocate the reparse data structure
DWORD dwBufSize = MAXIMUM_REPARSE_DATA_BUFFER_SIZE;
REPARSE_DATA_BUFFER* rdata;
rdata = (REPARSE_DATA_BUFFER*)malloc(dwBufSize);

// Query the reparse data
DWORD dwRetLen;
BOOL bRet = DeviceIoControl(hFile, FSCTL_GET_REPARSE_POINT, NULL, 0, rdata, dwBufSize, &dwRetLen, NULL);
if (bRet == FALSE)
{
printf(("DeviceIoControl failed with error: %d\n"), GetLastError());
CloseHandle(hFile);
return;
}
CloseHandle(hFile);

if (IsReparseTagMicrosoft(rdata->ReparseTag))
{
if (rdata->ReparseTag == IO_REPARSE_TAG_SYMLINK)
{
printf("Symbolic-Link\n");
size_t slen = rdata->SymbolicLinkReparseBuffer.SubstituteNameLength / sizeof(WCHAR);
WCHAR *szSubName = new WCHAR[slen + 1];
wcsncpy_s(szSubName, slen + 1, &rdata->SymbolicLinkReparseBuffer.PathBuffer[rdata->SymbolicLinkReparseBuffer.SubstituteNameOffset / sizeof(WCHAR)], slen);
szSubName[slen] = 0;
printf("SubstitutionName (len: %d): '%S'\n", rdata->SymbolicLinkReparseBuffer.SubstituteNameLength, szSubName);
delete[] szSubName;

size_t plen = rdata->SymbolicLinkReparseBuffer.PrintNameLength / sizeof(WCHAR);
WCHAR *szPrintName = new WCHAR[plen + 1];
wcsncpy_s(szPrintName, plen + 1, &rdata->SymbolicLinkReparseBuffer.PathBuffer[rdata->SymbolicLinkReparseBuffer.PrintNameOffset / sizeof(WCHAR)], plen);
szPrintName[plen] = 0;
printf("PrintName (len: %d): '%S'\n", rdata->SymbolicLinkReparseBuffer.PrintNameLength, szPrintName);
delete[] szPrintName;
}
else if (rdata->ReparseTag == IO_REPARSE_TAG_MOUNT_POINT)
{
printf("Mount-Point\n");
size_t slen = rdata->MountPointReparseBuffer.SubstituteNameLength / sizeof(WCHAR);
WCHAR *szSubName = new WCHAR[slen + 1];
wcsncpy_s(szSubName, slen + 1, &rdata->MountPointReparseBuffer.PathBuffer[rdata->MountPointReparseBuffer.SubstituteNameOffset / sizeof(WCHAR)], slen);
szSubName[slen] = 0;
printf("SubstitutionName (len: %d): '%S'\n", rdata->MountPointReparseBuffer.SubstituteNameLength, szSubName);
delete[] szSubName;

size_t plen = rdata->MountPointReparseBuffer.PrintNameLength / sizeof(WCHAR);
WCHAR *szPrintName = new WCHAR[plen + 1];
wcsncpy_s(szPrintName, plen + 1, &rdata->MountPointReparseBuffer.PathBuffer[rdata->MountPointReparseBuffer.PrintNameOffset / sizeof(WCHAR)], plen);
szPrintName[plen] = 0;
printf("PrintName (len: %d): '%S'\n", rdata->MountPointReparseBuffer.PrintNameLength, szPrintName);
delete[] szPrintName;
}
else
{
printf("No Mount-Point or Symblic-Link...\n");
}
}
else
{
printf(("Not a Microsoft-reparse point - could not query data!\n"));
}
free(rdata);

Я пытаюсь получить данные повторного анализа для файлов в заданной папке. Это мое REPARSE_DATA_BUFFER

typedef struct _REPARSE_DATA_BUFFER {
ULONG  ReparseTag;
USHORT  ReparseDataLength;
USHORT  Reserved;
union {
struct {
USHORT  SubstituteNameOffset;
USHORT  SubstituteNameLength;
USHORT  PrintNameOffset;
USHORT  PrintNameLength;
ULONG   Flags; // it seems that the docu is missing this entry (at least 2008-03-07)
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, *PREPARSE_DATA_BUFFER;

Я не знаю, где я ошибся. Пожалуйста, помогите мне исправить мой первый код.

1

Решение

ваш код, содержащий 2 ошибки, как минимум

Вы безоговорочно звоните FSCTL_GET_REPARSE_POINT для всех файлов, но вы должны сделать это только

if (FD.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {..}

в противном случае вы получили ERROR_NOT_A_REPARSE_POINT в DeviceIoControl а потом ErrorExit("DeviceIoControl"); казнены.

и вторая ошибка в этой строке:

DeviceIoControl(hFile, FSCTL_GET_REPARSE_POINT, NULL, 0, &rdata, dwBufSize, &bytesReturned, NULL)

&rdata — !!

когда должно быть

DeviceIoControl(hFile, FSCTL_GET_REPARSE_POINT, NULL, 0, rdata, dwBufSize, &bytesReturned, NULL)
5

Другие решения

Других решений пока нет …

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