#ifndef _NTIOAPI_H

#define IOCTL_MOUNTDEV_QUERY_DEVICE_NAME            CTL_CODE(MOUNTDEVCONTROLTYPE, 2, METHOD_BUFFERED, FILE_ANY_ACCESS)

#endif
View code on GitHub

// mountmgr.h

// CTL_CODE(0x004d, 0x002, METHOD_BUFFERED, FILE_ANY_ACCESS)
#define IOCTL_MOUNTDEV_QUERY_DEVICE_NAME 0x004D0008
View the official Windows Driver Kit DDI reference

NtDoc

This IOCTL is documented in Windows Driver Kit.

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Windows Driver Kit DDI reference (ni-mountmgr-ioctl_mountdev_query_device_name)

Description

Upon receiving this IOCTL a client driver must provide the (nonpersistent) device (or target) name for the volume. The mount manager uses the device name returned by the client as the target of a symbolic link. An example of a device name would be "\Device\HarddiskVolume1".

Support for this IOCTL by the mount manager clients is mandatory.

Parameters

Major code

IRP_MJ_DEVICE_CONTROL

Input buffer

None.

Input buffer length

None.

Output buffer

The mount manager client returns a variable-length structure of type MOUNTDEV_NAME at the beginning of the buffer at Irp->AssociatedIrp.SystemBuffer. The device name must be inserted at the address pointed to by the Name member of this structure.

Output buffer length

Parameters.DeviceIoControl.OutputBufferLength in the I/O stack location of the IRP indicates the size, in bytes, of the output buffer, which must be greater than or equal to sizeof(MOUNTDEV_NAME).

Input/output buffer

Input/output buffer length

Status block

The Information field is set to FIELD_OFFSET(MOUNTDEV_NAME, Name) + output->NameLength, or alternatively, output->NameLength + sizeof(USHORT), where output points to the buffer at Irp->AssociatedIrp.SystemBuffer.

If the operation is successful, the mount manager client must set the Information field to the length of the NULL-terminated string containing the device name and the Status field to STATUS_SUCCESS.

If the output buffer is too small to hold the device name, the mount manager client must set the Information field to sizeof(MOUNTDEV_NAME) and the Status field to STATUS_BUFFER_OVERFLOW. In addition, the mount manager client fills in the NameLength member of the MOUNTDEV_NAME structure.

Remarks

As a best practice, the implementer must not thread-synchronize and must not make blocking and/or Interprocess Communication (IPC) function calls.

For more information, see Supporting Mount Manager Requests in a Storage Class Driver.

IOCTL_MOUNTDEV_QUERY_DEVICE_NAME - NtDoc