IoCheckLinkShareAccess function (wdm.h)

Article
02/25/2022

The IoCheckLinkShareAccess routine is called by file system drivers (FSDs) or other highest-level drivers to check whether link shared access to a file object is permitted.

Syntax

NTSTATUS IoCheckLinkShareAccess(
  [in]                ACCESS_MASK        DesiredAccess,
  [in]                ULONG              DesiredShareAccess,
  [in, out, optional] PFILE_OBJECT       FileObject,
  [in, out, optional] PSHARE_ACCESS      ShareAccess,
  [in, out, optional] PLINK_SHARE_ACCESS LinkShareAccess,
  [in]                ULONG              IoShareAccessFlags
);

Parameters

[in] DesiredAccess

Specifies an ACCESS_MASK value that indicates the desired type of access to the given file object.

[in] DesiredShareAccess

Specifies the desired type of shared access to the file object for the current open request. The value of this parameter is usually the same as the ShareAccess parameter that is passed to the file system or highest-level driver by the I/O manager when the open request was made. This value can be zero, or any combination of the following:

FILE_SHARE_READ

FILE_SHARE_WRITE

FILE_SHARE_DELETE

[in, out, optional] FileObject

A pointer to the file object for which to check access for the current open request.

[in, out, optional] ShareAccess

A pointer to the common share-access data structure that is associated with FileObject. Drivers should treat this structure as opaque.

[in, out, optional] LinkShareAccess

A pointer to the common link share-access data structure (LINK_SHARE_ACCESS) that is associated with FileObject. Drivers should treat this structure as opaque.

[in] IoShareAccessFlags

A bitmask of these flags:

IO_SHARE_ACCESS_NO_WRITE_PERMISSION (0x80000000) specifies that the user has no write permission for the file. This flag is used to prevent opening a file for exclusive read access when the user does not have appropriate permissions.

IO_SHARE_ACCESS_NON_PRIMARY_STREAM (0x00000080) specifies that the stream is neither the primary data stream nor a directory stream.

IO_CHECK_SHARE_ACCESS_UPDATE_SHARE_ACCESS (0x00000001) indicates whether the SHARE_ACCESS structure is updated.

IO_CHECK_SHARE_ACCESS_DONT_UPDATE_FILE_OBJECT (0x00000002) indicates to not update FILE_OBJECT structure.

IO_CHECK_SHARE_ACCESS_DONT_CHECK_READ (0x00000004) indicates to not check read share access.

IO_CHECK_SHARE_ACCESS_DONT_CHECK_WRITE (0x00000008) indicates to not check write share access.

IO_CHECK_SHARE_ACCESS_DONT_CHECK_DELETE (0x00000010) indicates to not check delete share access.

IO_CHECK_SHARE_ACCESS_FORCE_CHECK (0x00000020) indicate to force check share access even if the request is not read/write/delete access.

IO_CHECK_SHARE_ACCESS_FORCE_USING_SCB (0x00000040) indicates to force check delete share access using ShareAccess regardless of whether LinkShareAccess is present or not.

Return value

The IoCheckLinkShareAccess routine returns STATUS_SUCCESS if the requester's access to the file object is compatible with the way in which it is currently open. If the request is denied because of a sharing violation, then STATUS_SHARING_VIOLATION is returned.

Remarks

The ShareAccess parameter must be locked against other accesses from other threads while this routine is executing. Otherwise the counts can be synchronization.

Requirements

Requirement	Value
Minimum supported client	Windows 10, version 1709
Minimum supported server	Windows Server 2016
Target Platform	Universal
Header	wdm.h
Library	Ntoskrnl.lib