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/*++
Copyright (c) 1989 Microsoft Corporation
Module Name:
deviosup.c
Abstract:
This module implements the memory locking routines for the netware
redirector.
Author:
Manny Weiser (mannyw) 10-Mar-1993
Revision History:
--*/
#include "procs.h"
//
// Local debug trace level
//
#define Dbg (DEBUG_TRACE_DEVIOSUP)
#ifdef ALLOC_PRAGMA
#pragma alloc_text( PAGE, NwMapUserBuffer )
#pragma alloc_text( PAGE, NwLockUserBuffer )
#endif
VOID
NwMapUserBuffer (
IN OUT PIRP Irp,
IN KPROCESSOR_MODE AccessMode,
OUT PVOID *UserBuffer
)
/*++
Routine Description:
This routine obtains a usable virtual address for the user buffer
for the current I/O request in the specified mode.
Arguments:
Irp - Pointer to the Irp for the request.
AccessMode - UserMode or KernelMode.
UserBuffer - Returns pointer to mapped user buffer.
Return Value:
None.
--*/
{
PAGED_CODE();
AccessMode;
//
// If there is no Mdl, then we must be in the Fsd, and we can simply
// return the UserBuffer field from the Irp.
//
if (Irp->MdlAddress == NULL) {
*UserBuffer = Irp->UserBuffer;
return;
}
//
// Get a system virtual address for the buffer.
//
*UserBuffer = MmGetSystemAddressForMdl( Irp->MdlAddress );
return;
}
VOID
NwLockUserBuffer (
IN OUT PIRP Irp,
IN LOCK_OPERATION Operation,
IN ULONG BufferLength
)
/*++
Routine Description:
This routine locks the specified buffer for the specified type of
access. The file system requires this routine since it does not
ask the I/O system to lock its buffers for direct I/O. This routine
may only be called from the FSD while still in the user context.
Arguments:
Irp - Pointer to the IRP for which the buffer is to be locked.
Operation - IoWriteAccess for read operations, or IoReadAccess for
write operations.
BufferLength - Length of user buffer.
Return Value:
None
--*/
{
PMDL mdl;
PAGED_CODE();
if (Irp->MdlAddress == NULL) {
//
// This read is bound for the current process. Perform the
// same functions as above, only do not switch processes.
//
mdl = IoAllocateMdl( Irp->UserBuffer, BufferLength, FALSE, TRUE, Irp );
if (mdl == NULL) {
ExRaiseStatus( STATUS_INSUFFICIENT_RESOURCES );
}
try {
MmProbeAndLockPages( mdl,
Irp->RequestorMode,
Operation );
} except(EXCEPTION_EXECUTE_HANDLER) {
IoFreeMdl( mdl );
Irp->MdlAddress = NULL;
ExRaiseStatus( FsRtlNormalizeNtstatus( GetExceptionCode(),
STATUS_INVALID_USER_BUFFER ));
}
}
}
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