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RxPrepareToReparseSymbolicLink function (rxprocs.h)

  • Artikel

RxPrepareToReparseSymbolicLink sets up the file object name to facilitate a reparse. This routine is used by the network mini-redirectors to traverse symbolic links.

Syntax

NTSTATUS RxPrepareToReparseSymbolicLink(
  PRX_CONTEXT     RxContext,
  BOOLEAN         SymbolicLinkEmbeddedInOldPath,
  PUNICODE_STRING NewPath,
  BOOLEAN         NewPathIsAbsolute,
  PBOOLEAN        ReparseRequired
);

Parameters

RxContext

A pointer to the RX_CONTEXT structure.

SymbolicLinkEmbeddedInOldPath

A Boolean value that indicates that a symbolic link was encountered. If the value is TRUE, a symbolic link was encountered as part of the traversal of the old path.

NewPath

A pointer to a Unicode string that contains the new path name to be traversed.

NewPathIsAbsolute

A Boolean value that indicates if the new path is absolute. If this value is FALSE, \Device\Mup should be prepended to NewPath. If this value is TRUE, the NewPath parameter is the full path to reparse. In this case, the buffer that contains NewPath is used directly, rather than allocating a new buffer.

ReparseRequired

A pointer to a Boolean value that indicates whether a reparse is required. If this value is TRUE, a reparse is required.

Return value

RxPrepareToReparseSymbolicLink returns STATUS_SUCCESS on success or one of the following error values on failure:

Return code Description
STATUS_ACCESS_DENIED
 A request to delete failed.
STATUS_INSUFFICIENT_RESOURCES
 There were insufficient resources available.
STATUS_INVALID_PARAMETER
 An invalid parameter was passed to the routine. This error will be returned if the MajorFunction member of RxContext is not IRP_MJ_CREATE.

Remarks

The RxPrepareToReparseSymbolicLink routine would only be used by a network mini-redirector that supports symbolic links and uses reparse points to implement symbolic links. The RxPrepareToReparseSymbolicLink routine would normally be called by a network mini-redirector from its MrxCreate callback routine.

The SymbolicLinkEmbeddedInOldPath parameter passed to this routine is very important. To preserve the correct semantics, it should be carefully used. For example, consider the old path \A\B\C\D where C happens to be a symbolic link. In this case, the symbolic link is embedded in the path and SymbolicLinkEmbeddedInOldPath should be set to TRUE. In contrast, this is very different from the case when D happens to be a symbolic link. In the former case, the reparse constitutes an intermediate step. In the second example, the reparse constitutes the final step of the name resolution and SymbolicLinkEmbeddedInOldPath should be set to FALSE.

If DELETE access is specified, the open or create operation is denied for all cases in which the symbolic link is not embedded. It is possible that if DELETE access were the only one specified, then the open attempt must succeed without reparse. This conforms UNIX symbolic link semantics.

As part of this routine, RxContext is also tagged appropriately. This ensures that the return value can be crosschecked with the invocation of this routine. Once RxPrepareToReparseSymbolicLink is invoked, the network mini redirector has to return STATUS_REPARSE.

The value of the ReparseRequired parameter assumes significance only if STATUS_SUCCESS is returned from this routine. If ReparseRequired is FALSE, this implies that no reparse attempt is required and the symbolic link file itself should be manipulated as opposed to the target of the link. If ReparseRequired is TRUE, this implies that a reparse attempt was successfully setup. In such cases, it is imperative that the network mini redirector returns STATUS_REPARSE for the associated MRxCreate call. RDBSS will initiate a check for this condition.

Requirements

Requirement Value
Target Platform Desktop
Header rxprocs.h (include Rxprocs.h)
IRQL <= APC_LEVEL

See also

MRxCreate