ECP_OPEN_PARAMETERS structure (ntifs.h)

The ECP_OPEN_PARAMETERS structure contains the extra create parameters (ECP) context that allows a caller to specify the purpose of opening of a file without interfering with existing handles and/or opportunistic locks (oplocks) on the file.

Syntax

typedef struct _ECP_OPEN_PARAMETERS {
  USHORT Size;
  USHORT Reserved;
  ULONG  Flags;
} ECP_OPEN_PARAMETERS, *PECP_OPEN_PARAMETERS;

Members

Size

Specifies the size of this context structure, in bytes.

Reserved

Reserved for future use. This must be initialized to 0.

Flags

Flags that specify the parameters or purpose for opening a file. Flags can be any combination of the following values:

Remarks

The ECP_OPEN_PARAMETERS_FLAG_OPEN_FOR_READ and ECP_OPEN_PARAMETERS_FLAG_OPEN_FOR_WRITE flags allow read/write access to encrypted files without having to actually open such files for read/write access. These ECP flags allow a kernel-mode component to open for metadata-only access, thus not interfering with other access while still getting the encryption context setup in order to do read/writes. A filter can set these flags to avoid conflicts with locking. Setting up the encryption state for read/write operations is expensive and are not typically done when files aren't opened for read/write access.

The system-defined GUID_ECP_OPEN_PARAMETERS value is used with this ECP context structure when calling ECP-related support routines such as FltAllocateExtraCreateParameter and FsRtlRemoveExtraCreateParameter.

See Introduction to extra create parameters for more information.

Requirements

See also

FltAllocateExtraCreateParameterList

FltCreateFileEx2