create.c

winNT技术操作系统,国外开放的原代码和LIUX一样

   /* perform the call */
   Status = NtCreateFile (&FileHandle,
			  dwDesiredAccess,
			  &ObjectAttributes,
			  &IoStatusBlock,
			  NULL,
			  FileAttributes,
			  dwShareMode,
			  dwCreationDisposition,
			  Flags,
			  EaBuffer,
			  EaLength);

   RtlFreeHeap(RtlGetProcessHeap(),
               0,
               NtPathU.Buffer);

   /* free the extended attributes buffer if allocated */
   if (EaBuffer != NULL)
   {
      RtlFreeHeap(RtlGetProcessHeap(),
                  0,
                  EaBuffer);
   }

   /* error */
   if (!NT_SUCCESS(Status))
   {
      /* In the case file creation was rejected due to CREATE_NEW flag
       * was specified and file with that name already exists, correct
       * last error is ERROR_FILE_EXISTS and not ERROR_ALREADY_EXISTS.
       * Note: RtlNtStatusToDosError is not the subject to blame here.
       */
      if (Status == STATUS_OBJECT_NAME_COLLISION &&
          dwCreationDisposition == FILE_CREATE)
      {
         SetLastError( ERROR_FILE_EXISTS );
      }
      else
      {
         SetLastErrorByStatus (Status);
      }

      return INVALID_HANDLE_VALUE;
   }

  /*
  create with OPEN_ALWAYS (FILE_OPEN_IF) returns info = FILE_OPENED or FILE_CREATED
  create with CREATE_ALWAYS (FILE_OVERWRITE_IF) returns info = FILE_OVERWRITTEN or FILE_CREATED
  */
  if (dwCreationDisposition == FILE_OPEN_IF)
  {
    SetLastError(IoStatusBlock.Information == FILE_OPENED ? ERROR_ALREADY_EXISTS : 0);
  }
  else if (dwCreationDisposition == FILE_OVERWRITE_IF)
  {
    SetLastError(IoStatusBlock.Information == FILE_OVERWRITTEN ? ERROR_ALREADY_EXISTS : 0);
  }

  return FileHandle;
}


/*
 * @implemented
 */
BOOLEAN
STDCALL
CreateSymbolicLinkW(IN LPCWSTR lpSymlinkFileName,
                    IN LPCWSTR lpTargetFileName,
                    IN DWORD dwFlags)
{
    IO_STATUS_BLOCK IoStatusBlock;
    OBJECT_ATTRIBUTES ObjectAttributes;
    HANDLE hSymlink = NULL;
    UNICODE_STRING SymlinkFileName = { 0, 0, NULL };
    UNICODE_STRING TargetFileName = { 0, 0, NULL };
    BOOLEAN bAllocatedTarget = FALSE, bRelativePath = FALSE;
    LPWSTR lpTargetFullFileName = NULL;
    SIZE_T cbPrintName;
    SIZE_T cbReparseData;
    PREPARSE_DATA_BUFFER pReparseData = NULL;
    PBYTE pBufTail;
    NTSTATUS Status;
    ULONG dwCreateOptions;
    DWORD dwErr;

    if(!lpSymlinkFileName || !lpTargetFileName || (dwFlags | SYMLINK_FLAG_DIRECTORY) != SYMLINK_FLAG_DIRECTORY)
    {
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;
    }

    if(dwFlags & SYMLINK_FLAG_DIRECTORY)
        dwCreateOptions = FILE_DIRECTORY_FILE;
    else
        dwCreateOptions = FILE_NON_DIRECTORY_FILE;

    switch(RtlDetermineDosPathNameType_U(lpTargetFileName))
    {
    case RtlPathTypeUnknown:
    case RtlPathTypeRooted:
    case RtlPathTypeRelative:
        bRelativePath = TRUE;
        RtlInitUnicodeString(&TargetFileName, lpTargetFileName);
        break;

    case RtlPathTypeDriveRelative:
        {
            LPWSTR FilePart;
            SIZE_T cchTargetFullFileName;

            cchTargetFullFileName = GetFullPathNameW(lpTargetFileName, 0, NULL, &FilePart);

            if(cchTargetFullFileName == 0)
            {
                dwErr = GetLastError();
                goto Cleanup;
            }

            lpTargetFullFileName = RtlAllocateHeap(RtlGetProcessHeap(), 0, cchTargetFullFileName * sizeof(WCHAR));

            if(lpTargetFullFileName == NULL)
            {
                dwErr = ERROR_NOT_ENOUGH_MEMORY;
                goto Cleanup;
            }

            if(GetFullPathNameW(lpTargetFileName, cchTargetFullFileName, lpTargetFullFileName, &FilePart) == 0)
            {
                dwErr = GetLastError();
                goto Cleanup;
            }
        }

        lpTargetFileName = lpTargetFullFileName;

        // fallthrough

    case RtlPathTypeUncAbsolute:
    case RtlPathTypeDriveAbsolute:
    case RtlPathTypeLocalDevice:
    case RtlPathTypeRootLocalDevice:
    default:
        if(!RtlDosPathNameToNtPathName_U(lpTargetFileName, &TargetFileName, NULL, NULL))
        {
            bAllocatedTarget = TRUE;
            dwErr = ERROR_INVALID_PARAMETER;
            goto Cleanup;
        }
    }

    cbPrintName = wcslen(lpTargetFileName) * sizeof(WCHAR);
    cbReparseData = FIELD_OFFSET(REPARSE_DATA_BUFFER, SymbolicLinkReparseBuffer.PathBuffer) + TargetFileName.Length + cbPrintName;
    pReparseData = RtlAllocateHeap(RtlGetProcessHeap(), 0, cbReparseData);

    if(pReparseData == NULL)
    {
        dwErr = ERROR_NOT_ENOUGH_MEMORY;
        goto Cleanup;
    }

    pBufTail = (PBYTE)(pReparseData->SymbolicLinkReparseBuffer.PathBuffer);

    pReparseData->ReparseTag = IO_REPARSE_TAG_SYMLINK;
    pReparseData->ReparseDataLength = cbReparseData - REPARSE_DATA_BUFFER_HEADER_SIZE;
    pReparseData->Reserved = 0;

    pReparseData->SymbolicLinkReparseBuffer.SubstituteNameOffset = 0;
    pReparseData->SymbolicLinkReparseBuffer.SubstituteNameLength = TargetFileName.Length;
    pBufTail += pReparseData->SymbolicLinkReparseBuffer.SubstituteNameOffset;
    RtlCopyMemory(pBufTail, TargetFileName.Buffer, TargetFileName.Length);

    pReparseData->SymbolicLinkReparseBuffer.PrintNameOffset = pReparseData->SymbolicLinkReparseBuffer.SubstituteNameLength;
    pReparseData->SymbolicLinkReparseBuffer.PrintNameLength = cbPrintName;
    pBufTail += pReparseData->SymbolicLinkReparseBuffer.PrintNameOffset;
    RtlCopyMemory(pBufTail, lpTargetFileName, cbPrintName);

    pReparseData->SymbolicLinkReparseBuffer.Flags = 0;

    if(bRelativePath)
        pReparseData->SymbolicLinkReparseBuffer.Flags |= 1; // TODO! give this lone flag a name

    if(!RtlDosPathNameToNtPathName_U(lpSymlinkFileName, &SymlinkFileName, NULL, NULL))
    {
        dwErr = ERROR_PATH_NOT_FOUND;
        goto Cleanup;
    }

    InitializeObjectAttributes(&ObjectAttributes, &SymlinkFileName, OBJ_CASE_INSENSITIVE, NULL, NULL);

    Status = NtCreateFile
    (
        &hSymlink,
        FILE_WRITE_ATTRIBUTES | DELETE | SYNCHRONIZE,
        &ObjectAttributes,
        &IoStatusBlock,
        NULL,
        FILE_ATTRIBUTE_NORMAL,
        0,
        FILE_CREATE,
        FILE_SYNCHRONOUS_IO_NONALERT | FILE_OPEN_REPARSE_POINT | dwCreateOptions,
        NULL,
        0
    );

    if(!NT_SUCCESS(Status))
    {
        dwErr = RtlNtStatusToDosError(Status);
        goto Cleanup;
    }

    Status = NtFsControlFile
    (
        hSymlink,
        NULL,
        NULL,
        NULL,
        &IoStatusBlock,
        FSCTL_SET_REPARSE_POINT,
        pReparseData,
        cbReparseData,
        NULL,
        0
    );

    if(!NT_SUCCESS(Status))
    {
        FILE_DISPOSITION_INFORMATION DispInfo;
        DispInfo.DeleteFile = TRUE;
        NtSetInformationFile(hSymlink, &IoStatusBlock, &DispInfo, sizeof(DispInfo), FileDispositionInformation);

        dwErr = RtlNtStatusToDosError(Status);
        goto Cleanup;
    }

    dwErr = NO_ERROR;

Cleanup:
    if(hSymlink)
        NtClose(hSymlink);

    RtlFreeUnicodeString(&SymlinkFileName);
    if (bAllocatedTarget)
    {
        RtlFreeHeap(RtlGetProcessHeap(),
                    0,
                    TargetFileName.Buffer);
    }

    if(lpTargetFullFileName)
        RtlFreeHeap(RtlGetProcessHeap(), 0, lpTargetFullFileName);

    if(pReparseData)
        RtlFreeHeap(RtlGetProcessHeap(), 0, pReparseData);

    if(dwErr)
    {
        SetLastError(dwErr);
        return FALSE;
    }

    return TRUE;
}


/*
 * @implemented
 */
BOOLEAN
STDCALL
CreateSymbolicLinkA(IN LPCSTR lpSymlinkFileName,
                    IN LPCSTR lpTargetFileName,
                    IN DWORD dwFlags)
{
    PWCHAR SymlinkW, TargetW;
    BOOL Ret;

    if(!lpSymlinkFileName || !lpTargetFileName)
    {
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;
    }

    if (!(SymlinkW = FilenameA2W(lpSymlinkFileName, FALSE)))
        return FALSE;

    if (!(TargetW = FilenameA2W(lpTargetFileName, TRUE)))
        return FALSE;

    Ret = CreateSymbolicLinkW(SymlinkW,
                              TargetW,
                              dwFlags);

    RtlFreeHeap(RtlGetProcessHeap(), 0, SymlinkW);
    RtlFreeHeap(RtlGetProcessHeap(), 0, TargetW);

    return Ret;
}


/* EOF */