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DA_GET_NFS_ATTRIBUTES control code

The DA_GET_NFS_ATTRIBUTES control code queries additional information about an NFS share.

To perform this operation, call the DeviceIoControl function with the following parameters.


BOOL 
   WINAPI 
   DeviceIoControl( (HANDLE)       hDevice,               // handle to device
                    (DWORD)        DA_GET_NFS_ATTRIBUTES, // dwIoControlCode
                                   NULL,                  // lpInBuffer
                                   0,                     // nInBufferSize
                    (LPDWORD)      lpOutBuffer,           // output buffer
                    (DWORD)        nOutBufferSize,        // size of output buffer
                    (LPDWORD)      lpBytesReturned,       // number of bytes returned
                    (LPOVERLAPPED) lpOverlapped );        // OVERLAPPED structure

Parameters

hDevice [in]

A handle to a file on the NFS share. To obtain this handle, call the CreateFile function.

dwIoControlCode [in]

The control code for the operation. Use DA_GET_NFS_ATTRIBUTES for this operation.

lpInBuffer

Not used with this operation; set to NULL.

nInBufferSize [in]

Not used with this operation; set to zero.

lpOutBuffer [out]

A pointer to the output buffer, which contains an NFS_FILE_ATTRIBUTES structure. For more information, see the Remarks section.

nOutBufferSize [in]

The size of the output buffer, in bytes.

lpBytesReturned [out]

A pointer to a variable that receives the size of the data stored in the output buffer, in bytes.

If the output buffer is too small, the call fails, GetLastError returns ERROR_INSUFFICIENT_BUFFER, and lpBytesReturned is zero.

If lpOverlapped is NULL, lpBytesReturned cannot be NULL. Even when an operation returns no output data and lpOutBuffer is NULL, DeviceIoControl makes use of lpBytesReturned. After such an operation, the value of lpBytesReturned is meaningless.

If lpOverlapped is not NULL, lpBytesReturned can be NULL. If this parameter is not NULL and the operation returns data, lpBytesReturned is meaningless until the overlapped operation has completed. To retrieve the number of bytes returned, call GetOverlappedResult. If the hDevice parameter is associated with an I/O completion port, you can retrieve the number of bytes returned by calling GetQueuedCompletionStatus.

lpOverlapped [in]

A pointer to an OVERLAPPED structure.

If hDevice was opened without specifying FILE_FLAG_OVERLAPPED, lpOverlapped is ignored.

If hDevice was opened with the FILE_FLAG_OVERLAPPED flag, the operation is performed as an overlapped (asynchronous) operation. In this case, lpOverlapped must point to a valid OVERLAPPED structure that contains a handle to an event object. Otherwise, the function fails in unpredictable ways.

For overlapped operations, DeviceIoControl returns immediately, and the event object is signaled when the operation has been completed. Otherwise, the function does not return until the operation has been completed or an error occurs.

Return value

If the operation completes successfully, DeviceIoControl returns a nonzero value.

If the operation fails or is pending, DeviceIoControl returns zero. To get extended error information, call GetLastError.

Remarks

This control code has no associated header file. You must define the control code and data structures as follows.

#define DEVICE_DA_RDR 0x80000  
 
#define DA_GET_NFS_ATTRIBUTES CTL_CODE(DEVICE_DA_RDR, 0x804, METHOD_BUFFERED, FILE_ANY_ACCESS)

typedef struct _NFS_SPEC_DATA {  
    ULONG               SpecData1;
    ULONG               SpecData2;
} NFS_SPEC_DATA, *PNFS_SPEC_DATA;

typedef struct _NFS_TIME {
    ULONG        Seconds;
    ULONG        nSeconds;
} NFS_TIME, *PNFS_TIME;

#define NFS_TYPE_REG         1
#define NFS_TYPE_DIR         2
#define NFS_TYPE_BLK         3
#define NFS_TYPE_CHR         4
#define NFS_TYPE_LNK         5
#define NFS_TYPE_SOCK        6
#define NFS_TYPE_FIFO        7

typedef struct _NFS_FILE_ATTRIBUTES {  
    ULONG               FileType;  
    ULONG               Mode;  
    ULONG               NLink;  
    ULONG               Uid;  
    ULONG               Gid;  
    ULONGLONG           Size;  
    ULONGLONG           Used;
    NFS_SPEC_DATA       Rdev;
    ULONGLONG           Fsid;  
    ULONGLONG           FileId;  
    NFS_TIME            AccessTime;  
    NFS_TIME            ModifyTime;  
    NFS_TIME            ChangeTime;  
} NFS_FILE_ATTRIBUTES, *PNFS_FILE_ATTRIBUTES;

typedef struct _DA_FILE_ATTRIBUTES {  
    NFS_FILE_ATTRIBUTES FileAttributes;  
    ULONG               Version;  
} DA_FILE_ATTRIBUTES, *PDA_FILE_ATTRIBUTES;

The structure members can be described as follows.

SpecData1

An opaque value that is used for special file types such as block-special, character-special and FIFO files.

SpecData2

An opaque value that is used for special file types such as block-special, character-special and FIFO files.

Seconds

A 64-bit value representing the seconds since January 1, 1970 (UTC).

nSeconds

The number of nanoseconds to be added to the Seconds member.

FileType

The NFS file type of the share.

NFS File TypeDescription

NFS_TYPE_REG

A regular file.

NFS_TYPE_DIR

A directory.

NFS_TYPE_BLK

A block-special file.

NFS_TYPE_CHR

A character-special file.

NFS_TYPE_LNK

A symbolic link.

NFS_TYPE_SOCK

A Windows socket.

NFS_TYPE_FIFO

A FIFO file.

 

Mode

The file mode.

NLink

The number of links to the share.

Uid

The UNIX user identifier (UID).

Gid

The UNIX group identifier (GID).

Size

The file size, in bytes.

Used

The file size used, in bytes. This is the same as the file size.

Rdev

The device identifier.

Fsid

The file system identifier.

FileId

The file identifier.

AccessTime

The last access time.

ModifyTime

The last modification time.

ChangeTime

The last change time.

FileAttributes

An NFS_FILE_ATTRIBUTES structure.

Note  For more detailed descriptions of the members of this structure, see the fattr3 structure in the NFS Version 3 Protocol Specification (as defined in RFC 1813).

Version

Specifies whether the connection on which the handle to the NFS share was created is over NFS Version 2 or NFS Version 3 protocol.

ValueDescription

2

NFS Version 2

3

NFS Version 3

 

Requirements

Minimum supported client

None supported

Minimum supported server

Windows Server 2008

End of client support

None supported

End of server support

Windows Server 2008 R2

See also

DeviceIoControl

 

 

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