354 lines
11 KiB
C
354 lines
11 KiB
C
/*++
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Copyright (c) 1991 Microsoft Corporation
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Module Name:
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unc.c
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Abstract:
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This file contains functions to support multiple UNC providers on a single NT machine.
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Author:
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Manny Weiser [MannyW] 20-Dec-1991
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Revision History:
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Isaac Heizer [IsaacHe] 16-Nov-1994 Defer loading the MUP
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Rewrite
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Milan Shah [MilanS] 7-Mar-1996 Check for Dfs client status
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before loading the MUP
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--*/
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#include "fsrtlp.h"
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#include <zwapi.h>
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#include <ntddmup.h>
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#include <ntddnull.h>
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static WCHAR MupRegKey[] = L"\\Registry\\Machine\\System\\CurrentControlSet\\Services\\Mup";
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static WCHAR UNCSymbolicLink[] = L"\\DosDevices\\UNC";
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static WCHAR DevNull[] = L"\\Device\\Null";
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static WCHAR DevMup[] = DD_MUP_DEVICE_NAME;
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// Define a tag for general pool allocations from this module
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#undef MODULE_POOL_TAG
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#define MODULE_POOL_TAG ('nuSF')
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// Local prototypes
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NTSTATUS FsRtlpRegisterProviderWithMUP (IN HANDLE mupHandle, IN PUNICODE_STRING RedirDevName, IN BOOLEAN MailslotsSupported);
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NTSTATUS FsRtlpOpenDev(IN OUT PHANDLE Handle, IN LPWSTR DevNameStr);
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VOID FsRtlpSetSymbolicLink(IN PUNICODE_STRING DevName OPTIONAL);
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BOOLEAN FsRtlpIsDfsEnabled();
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text(PAGE, FsRtlpRegisterProviderWithMUP)
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#pragma alloc_text(PAGE, FsRtlpOpenDev)
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#pragma alloc_text(PAGE, FsRtlpSetSymbolicLink)
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#pragma alloc_text(PAGE, FsRtlDeregisterUncProvider)
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#pragma alloc_text(PAGE, FsRtlRegisterUncProvider)
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#endif
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// We defer calling the MUP with the registration data until
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// the second redir loads and Dfs is disabled.
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// This structure holds the data necessary to make that call.
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struct {
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HANDLE MupHandle;
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HANDLE ReturnedHandle;
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UNICODE_STRING RedirDevName;
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BOOLEAN MailslotsSupported;
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} FsRtlpDRD = {0};
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KSEMAPHORE FsRtlpUncSemaphore;// Resource protection
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ULONG FsRtlpRedirs = 0;// Number of times we've loaded redirs.
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NTSTATUS FsRtlpRegisterProviderWithMUP(IN HANDLE mupHandle, IN PUNICODE_STRING RedirDevName, IN BOOLEAN MailslotsSupported)
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/*++
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Routine Description:
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This private routine does the FSCTL to the MUP to tell it about a new redir
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Arguments:
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mupHandle - Handle to the MUP
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RedirDevName - The device name of the redir.
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MailslotsSupported - If TRUE, this redir supports mailslots.
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Return Value:
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NTSTATUS - The status of the operation.
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--*/
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{
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NTSTATUS status;
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IO_STATUS_BLOCK ioStatusBlock;
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ULONG paramLength;
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PREDIRECTOR_REGISTRATION params;
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PAGED_CODE();
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paramLength = sizeof( REDIRECTOR_REGISTRATION ) + RedirDevName->Length;
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params = ExAllocatePoolWithTag( NonPagedPool, paramLength, MODULE_POOL_TAG );
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if( params == NULL )
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return STATUS_INSUFFICIENT_RESOURCES;
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params->DeviceNameOffset = sizeof( REDIRECTOR_REGISTRATION );
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params->DeviceNameLength = RedirDevName->Length;
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params->MailslotsSupported = MailslotsSupported;
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RtlMoveMemory((PCHAR)params + params->DeviceNameOffset, RedirDevName->Buffer, RedirDevName->Length);
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status = NtFsControlFile(mupHandle, 0, NULL, NULL, &ioStatusBlock, FSCTL_MUP_REGISTER_UNC_PROVIDER, params, paramLength, NULL, 0);
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if ( status == STATUS_PENDING ) {
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status = NtWaitForSingleObject( mupHandle, TRUE, NULL );
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}
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if ( NT_SUCCESS( status ) ) {
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status = ioStatusBlock.Status;
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}
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ASSERT( NT_SUCCESS( status ) );
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ExFreePool( params );
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return status;
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}
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NTSTATUS FsRtlpOpenDev(IN OUT PHANDLE Handle, IN LPWSTR DevNameStr)
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{
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NTSTATUS status;
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UNICODE_STRING DevName;
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OBJECT_ATTRIBUTES objectAttributes;
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IO_STATUS_BLOCK ioStatusBlock;
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PAGED_CODE();
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RtlInitUnicodeString( &DevName, DevNameStr );
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InitializeObjectAttributes(&objectAttributes, &DevName, 0, 0, NULL);
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status = ZwCreateFile(Handle, GENERIC_WRITE, &objectAttributes, &ioStatusBlock, NULL, FILE_ATTRIBUTE_NORMAL, FILE_SHARE_READ | FILE_SHARE_WRITE, FILE_OPEN, 0, NULL, 0);
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if ( NT_SUCCESS( status ) ) {
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status = ioStatusBlock.Status;
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}
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if( !NT_SUCCESS( status ) ) {
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*Handle = (HANDLE)-1;
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}
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return status;
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}
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VOID FsRtlpSetSymbolicLink( IN PUNICODE_STRING DevName OPTIONAL )
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{
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NTSTATUS status;
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UNICODE_STRING UncSymbolicName;
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PAGED_CODE();
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RtlInitUnicodeString( &UncSymbolicName, UNCSymbolicLink );
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(VOID)IoDeleteSymbolicLink( &UncSymbolicName );
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if( ARGUMENT_PRESENT( DevName ) ) {
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status = IoCreateSymbolicLink( &UncSymbolicName, DevName );
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ASSERT( NT_SUCCESS( status ) );
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}
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}
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NTSTATUS FsRtlRegisterUncProvider(IN OUT PHANDLE MupHandle, IN PUNICODE_STRING RedirDevName, IN BOOLEAN MailslotsSupported)
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/*++
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Routine Description:
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This routine registers a redir as a UNC provider.
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Arguments:
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Handle - Pointer to a handle. The handle is returned by the routine to be used when calling FsRtlDeregisterUncProvider.
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It is valid only if the routines returns STATUS_SUCCESS.
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RedirDevName - The device name of the redir.
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MailslotsSupported - If TRUE, this redir supports mailslots.
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Return Value:
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NTSTATUS - The status of the operation.
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--*/
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{
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NTSTATUS status;
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HANDLE mupHandle = (HANDLE)-1;
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UNICODE_STRING mupDriverName;
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BOOLEAN dfsEnabled;
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PAGED_CODE();
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KeWaitForSingleObject(&FsRtlpUncSemaphore, Executive, KernelMode, FALSE, NULL );
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if (FsRtlpRedirs == 0) {
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dfsEnabled = FsRtlpIsDfsEnabled();
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if (dfsEnabled) {
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FsRtlpRedirs = 1;
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RtlZeroMemory((PVOID) &FsRtlpDRD, sizeof(FsRtlpDRD));
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}
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}
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switch( FsRtlpRedirs ) {
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case 0:
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// Ok, the MUP isn't there and we don't need to use the MUP for the first redir.
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// We need to return a handle, but we're not really using the MUP yet.
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// And we may never use it (if there's only 1 redir).
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// Return a handle to the NULL device object, since we're committed to returning a handle to our caller.
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// Our caller isn't supposed to do anything with the handle except to call FsRtlDeregisterUncProvider() with it.
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status = FsRtlpOpenDev( &mupHandle, DevNull );
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if( !NT_SUCCESS( status ) )
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break;
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// Save up enough state to allow us to call the MUP later with this registration info if necessary.
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FsRtlpDRD.RedirDevName.Buffer = ExAllocatePoolWithTag( NonPagedPool, RedirDevName->MaximumLength, MODULE_POOL_TAG );
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if( FsRtlpDRD.RedirDevName.Buffer == NULL ) {
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status = STATUS_INSUFFICIENT_RESOURCES;
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break;
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}
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FsRtlpDRD.RedirDevName.Length = RedirDevName->Length;
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FsRtlpDRD.RedirDevName.MaximumLength = RedirDevName->MaximumLength;
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RtlMoveMemory((PCHAR)FsRtlpDRD.RedirDevName.Buffer, RedirDevName->Buffer, RedirDevName->MaximumLength);
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FsRtlpDRD.MailslotsSupported = MailslotsSupported;
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FsRtlpDRD.ReturnedHandle = mupHandle;
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FsRtlpDRD.MupHandle = (HANDLE)-1;
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FsRtlpSetSymbolicLink( RedirDevName );// Set the UNC symbolic link to point to the redir we just loaded
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break;
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default:
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// This is the second or later redir load -- MUST use the MUP
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status = FsRtlpOpenDev( &mupHandle, DevMup );
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if( !NT_SUCCESS( status ) ) {
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RtlInitUnicodeString( &mupDriverName, MupRegKey );
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(VOID)ZwLoadDriver( &mupDriverName );
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status = FsRtlpOpenDev( &mupHandle, DevMup );
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if( !NT_SUCCESS( status ) )
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break;
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}
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// See if we need to tell the MUP about the first redir that registered
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if( FsRtlpDRD.RedirDevName.Buffer ) {
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status = FsRtlpRegisterProviderWithMUP( mupHandle, &FsRtlpDRD.RedirDevName, FsRtlpDRD.MailslotsSupported );
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if( !NT_SUCCESS( status ) )
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break;
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FsRtlpDRD.MupHandle = mupHandle;
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ExFreePool( FsRtlpDRD.RedirDevName.Buffer );
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FsRtlpDRD.RedirDevName.Buffer = NULL;
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// Set the UNC symbolic link to point to the MUP
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RtlInitUnicodeString( &mupDriverName, DevMup );
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FsRtlpSetSymbolicLink( &mupDriverName );
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status = FsRtlpOpenDev( &mupHandle, DevMup );
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if( !NT_SUCCESS( status ) )
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break;
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}
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// Pass the request to the MUP for this redir
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status = FsRtlpRegisterProviderWithMUP( mupHandle, RedirDevName, MailslotsSupported );
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break;
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}
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if( NT_SUCCESS( status ) ) {
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FsRtlpRedirs++;
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*MupHandle = mupHandle;
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} else {
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if( mupHandle != (HANDLE)-1 && mupHandle != NULL ) {
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ZwClose( mupHandle );
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}
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*MupHandle = (HANDLE)-1;
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}
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KeReleaseSemaphore(&FsRtlpUncSemaphore, 0, 1, FALSE );
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return status;
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}
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VOID FsRtlDeregisterUncProvider(IN HANDLE Handle)
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/*++
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Routine Description:
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This routine deregisters a redir as a UNC provider.
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Arguments:
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Handle - A handle to the Multiple UNC router, returned by the registration call.
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--*/
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{
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NTSTATUS status;
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PAGED_CODE();
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if( Handle == (HANDLE)-1 || Handle == NULL )
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return;
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status = ZwClose( Handle );
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if( !NT_SUCCESS( status ) ) {
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return;
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}
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KeWaitForSingleObject(&FsRtlpUncSemaphore, Executive, KernelMode, FALSE, NULL );
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ASSERT( FsRtlpRedirs > 0 );
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if( Handle == FsRtlpDRD.ReturnedHandle ) {
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// The first redir in the system is closing. Release the state we saved for it, and pass the close on to the MUP if necessary
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if( FsRtlpDRD.RedirDevName.Buffer != NULL ) {
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ExFreePool( FsRtlpDRD.RedirDevName.Buffer );
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FsRtlpDRD.RedirDevName.Buffer = NULL;
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}
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if( FsRtlpDRD.MupHandle != (HANDLE)-1 ) {
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ZwClose( FsRtlpDRD.MupHandle );
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FsRtlpDRD.MupHandle = (HANDLE)-1;
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}
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FsRtlpDRD.ReturnedHandle = (HANDLE)-1;
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}
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if( --FsRtlpRedirs == 0 ) {
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FsRtlpSetSymbolicLink( (PUNICODE_STRING)NULL );
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}
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KeReleaseSemaphore(&FsRtlpUncSemaphore, 0, 1, FALSE );
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}
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BOOLEAN FsRtlpIsDfsEnabled()
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/*++
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Routine Description:
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This routine checks a registry key to see if the Dfs client is enabled.
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The client is assumed to be enabled by default, and disabled only if there is a registry value indicating that it should be disabled.
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Return Value:
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TRUE if Dfs client is enabled, FALSE otherwise.
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--*/
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{
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NTSTATUS status;
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HANDLE mupRegHandle;
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OBJECT_ATTRIBUTES objectAttributes;
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ULONG valueSize;
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BOOLEAN dfsEnabled = TRUE;
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UNICODE_STRING mupRegKey = {
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sizeof(MupRegKey) - sizeof(WCHAR),
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sizeof(MupRegKey),
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MupRegKey};
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#define DISABLE_DFS_VALUE_NAME L"DisableDfs"
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UNICODE_STRING disableDfs = {
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sizeof(DISABLE_DFS_VALUE_NAME) - sizeof(WCHAR),
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sizeof(DISABLE_DFS_VALUE_NAME),
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DISABLE_DFS_VALUE_NAME};
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struct {
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KEY_VALUE_PARTIAL_INFORMATION Info;
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ULONG Buffer;
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} disableDfsValue;
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InitializeObjectAttributes(&objectAttributes, &mupRegKey, OBJ_CASE_INSENSITIVE, 0, NULL);
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status = ZwOpenKey(&mupRegHandle, KEY_READ, &objectAttributes);
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if (NT_SUCCESS(status)) {
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status = ZwQueryValueKey(mupRegHandle, &disableDfs, KeyValuePartialInformation, (PVOID) &disableDfsValue, sizeof(disableDfsValue), &valueSize);
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if (NT_SUCCESS(status) && disableDfsValue.Info.Type == REG_DWORD) {
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if ( (*((PULONG) disableDfsValue.Info.Data)) == 1 )
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dfsEnabled = FALSE;
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}
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ZwClose( mupRegHandle );
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}
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return( dfsEnabled );
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} |