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From: vampire@cross.garlic ((vampire))
Newsgroups: comp.os.ms-windows.programmer.nt.kernel-mode
Subject: Re: Retrieve name of a device object
Date: Sun, 02 Nov 1997 07:17:41 GMT
Organization: Unspecified Organization
Lines: 36
Message-ID: <345c285a.237690721@news.ibm.net.il>
References: <345a3eb4.11883787@news.iaehv.nl> <345AC565.7A71@ftp.com>
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>OBJECT_NAME_INFORMATION is (accidentally?) defined in NTDDK.H 
>and is actually a UNICODE_STRING:
>
>typedef struct _OBJECT_NAME_INFORMATION {
>    UNICODE_STRING Name;
>} OBJECT_NAME_INFORMATION, *POBJECT_NAME_INFORMATION;
>
>Given a device object, this function seems to return its
>original device name (even though the device may be opened 
>through a symbolic link). At least I was able to translate 
>a COM port device object into \Device\SerialX name. The code 
>looked like this:
>
>char Buffer[256];
>NTSTATUS ObStatus;
>ULONG ReturnLength = 0;
>OBJECT_NAME_INFORMATION * Info = (OBJECT_NAME_INFORMATION *)Buffer;
>RtlZeroMemory(Info, sizeof(OBJECT_NAME_INFORMATION));
>ObStatus = ObQueryNameString( Port->FileObject->DeviceObject,
>                              Info, sizeof(Buffer),
>                              &ReturnLength);
>if ( NT_SUCCESS(ObStatus) && ReturnLength )
>    if ( Info->Name.Length && Info->Name.Buffer )
>    {
>        TRACE1("Device: %wZ\n",&Info->Name);
>        ..........
>    }
>
>Regards,
>-Slava

Watch out here. From my exprecience, you absolutely do not pass a
PUNICODE as a parameter, but rather a pointer to a large buffer. The
header of the buffer will be initialized (by the function) to a
unicode string, with unicode.buffer pointing to the rest of the
buffer.