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810 lines
17 KiB
810 lines
17 KiB
/*++
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Copyright (c) 1989-2000 Microsoft Corporation
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Module Name:
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PrefxSup.c
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Abstract:
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This module implements the Udfs Prefix support routines
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// @@BEGIN_DDKSPLIT
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Author:
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Dan Lovinger [DanLo] 8-Oct-1996
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Revision History:
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// @@END_DDKSPLIT
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--*/
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#include "UdfProcs.h"
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//
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// The Bug check file id for this module
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//
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#define BugCheckFileId (UDFS_BUG_CHECK_PREFXSUP)
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//
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// The local debug trace level
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//
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#define Dbg (UDFS_DEBUG_LEVEL_READ)
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//
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// Local support routines.
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//
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PLCB
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UdfFindNameLink (
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IN PIRP_CONTEXT IrpContext,
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IN PRTL_SPLAY_LINKS *RootNode,
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IN PUNICODE_STRING Name
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);
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BOOLEAN
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UdfInsertNameLink (
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IN PIRP_CONTEXT IrpContext,
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IN PRTL_SPLAY_LINKS *RootNode,
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IN PLCB NameLink
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);
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text(PAGE, UdfFindNameLink)
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#pragma alloc_text(PAGE, UdfFindPrefix)
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#pragma alloc_text(PAGE, UdfInitializeLcbFromDirContext)
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#pragma alloc_text(PAGE, UdfInsertNameLink)
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#pragma alloc_text(PAGE, UdfInsertPrefix)
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#pragma alloc_text(PAGE, UdfRemovePrefix)
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#endif
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PLCB
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UdfInsertPrefix (
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IN PIRP_CONTEXT IrpContext,
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IN PFCB Fcb,
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IN PUNICODE_STRING Name,
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IN BOOLEAN ShortNameMatch,
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IN BOOLEAN IgnoreCase,
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IN PFCB ParentFcb
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)
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/*++
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Routine Description:
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This routine inserts an Lcb linking the two Fcbs together.
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Arguments:
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Fcb - This is the Fcb whose name is being inserted into the tree.
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Name - This is the name for the component.
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ShortNameMatch - Indicates whether this name was found on an explicit 8.3 search
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IgnoreCase - Indicates if we should insert into the case-insensitive tree.
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ParentFcb - This is the ParentFcb. The prefix tree is attached to this.
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Return Value:
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PLCB - the Lcb inserted.
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--*/
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{
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PLCB Lcb;
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PRTL_SPLAY_LINKS *TreeRoot;
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PLIST_ENTRY ListLinks;
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ULONG Flags;
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PWCHAR NameBuffer;
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PAGED_CODE();
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//
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// Check inputs.
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//
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ASSERT_IRP_CONTEXT( IrpContext );
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ASSERT_FCB( Fcb );
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ASSERT_EXCLUSIVE_FCB( Fcb );
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ASSERT_EXCLUSIVE_FCB( ParentFcb );
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ASSERT_FCB_INDEX( ParentFcb );
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//
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// It must be the case that an index Fcb is only referenced by a single index. Now
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// we walk the child's Lcb queue to insure that if any prefixes have already been
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// inserted, they all refer to the index Fcb we are linking to. This is the only way
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// we can detect directory cross-linkage.
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//
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if (SafeNodeType( Fcb ) == UDFS_NTC_FCB_INDEX) {
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for (ListLinks = Fcb->ParentLcbQueue.Flink;
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ListLinks != &Fcb->ParentLcbQueue;
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ListLinks = ListLinks->Flink) {
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Lcb = CONTAINING_RECORD( ListLinks, LCB, ChildFcbLinks );
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if (Lcb->ParentFcb != ParentFcb) {
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UdfRaiseStatus( IrpContext, STATUS_DISK_CORRUPT_ERROR );
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}
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}
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}
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//
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// Capture the separate cases.
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//
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if (IgnoreCase) {
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TreeRoot = &ParentFcb->IgnoreCaseRoot;
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Flags = LCB_FLAG_IGNORE_CASE;
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} else {
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TreeRoot = &ParentFcb->ExactCaseRoot;
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Flags = 0;
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}
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if (ShortNameMatch) {
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SetFlag( Flags, LCB_FLAG_SHORT_NAME );
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}
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//
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// Allocate space for the Lcb.
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//
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if ( sizeof( LCB ) + Name->Length > SIZEOF_LOOKASIDE_LCB ) {
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Lcb = FsRtlAllocatePoolWithTag( UdfPagedPool,
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sizeof( LCB ) + Name->Length,
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TAG_LCB );
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SetFlag( Flags, LCB_FLAG_POOL_ALLOCATED );
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} else {
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Lcb = ExAllocateFromPagedLookasideList( &UdfLcbLookasideList );
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}
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//
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// Set the type and size.
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//
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Lcb->NodeTypeCode = UDFS_NTC_LCB;
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Lcb->NodeByteSize = sizeof( LCB ) + Name->Length;
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//
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// Initialize the name-based file attributes.
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//
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Lcb->FileAttributes = 0;
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//
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// Set up the filename in the Lcb.
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//
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Lcb->FileName.Length =
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Lcb->FileName.MaximumLength = Name->Length;
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Lcb->FileName.Buffer = Add2Ptr( Lcb, sizeof( LCB ), PWCHAR );
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RtlCopyMemory( Lcb->FileName.Buffer,
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Name->Buffer,
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Name->Length );
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//
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// Insert the Lcb into the prefix tree.
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//
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Lcb->Flags = Flags;
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if (!UdfInsertNameLink( IrpContext,
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TreeRoot,
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Lcb )) {
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//
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// This will very rarely occur.
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//
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UdfFreePool( &Lcb );
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Lcb = UdfFindNameLink( IrpContext,
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TreeRoot,
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Name );
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if (Lcb == NULL) {
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//
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// Even worse.
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//
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UdfRaiseStatus( IrpContext, STATUS_DRIVER_INTERNAL_ERROR );
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}
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return Lcb;
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}
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//
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// Link the Fcbs together through the Lcb.
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//
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Lcb->ParentFcb = ParentFcb;
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Lcb->ChildFcb = Fcb;
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InsertHeadList( &ParentFcb->ChildLcbQueue, &Lcb->ParentFcbLinks );
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InsertHeadList( &Fcb->ParentLcbQueue, &Lcb->ChildFcbLinks );
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//
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// Initialize the reference count.
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//
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Lcb->Reference = 0;
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return Lcb;
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}
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VOID
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UdfRemovePrefix (
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IN PIRP_CONTEXT IrpContext,
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IN PLCB Lcb
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)
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/*++
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Routine Description:
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This routine is called to remove a given prefix of an Fcb.
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Arguments:
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Lcb - the prefix being removed.
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Return Value:
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None
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--*/
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{
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PAGED_CODE();
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//
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// Check inputs.
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//
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ASSERT_IRP_CONTEXT( IrpContext );
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ASSERT_LCB( Lcb );
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//
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// Check the acquisition of the two Fcbs.
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//
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ASSERT_EXCLUSIVE_FCB_OR_VCB( Lcb->ParentFcb );
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ASSERT_EXCLUSIVE_FCB_OR_VCB( Lcb->ChildFcb );
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//
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// Now remove the linkage and delete the Lcb.
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//
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RemoveEntryList( &Lcb->ParentFcbLinks );
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RemoveEntryList( &Lcb->ChildFcbLinks );
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if (FlagOn( Lcb->Flags, LCB_FLAG_IGNORE_CASE )) {
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Lcb->ParentFcb->IgnoreCaseRoot = RtlDelete( &Lcb->Links );
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} else {
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Lcb->ParentFcb->ExactCaseRoot = RtlDelete( &Lcb->Links );
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}
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if (FlagOn( Lcb->Flags, LCB_FLAG_POOL_ALLOCATED )) {
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ExFreePool( Lcb );
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} else {
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ExFreeToPagedLookasideList( &UdfLcbLookasideList, Lcb );
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}
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return;
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}
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PLCB
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UdfFindPrefix (
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IN PIRP_CONTEXT IrpContext,
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IN OUT PFCB *CurrentFcb,
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IN OUT PUNICODE_STRING RemainingName,
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IN BOOLEAN IgnoreCase
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)
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/*++
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Routine Description:
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This routine begins from the given CurrentFcb and walks through all of
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components of the name looking for the longest match in the prefix
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splay trees. The search is relative to the starting Fcb so the
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full name may not begin with a '\'. On return this routine will
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update Current Fcb with the lowest point it has travelled in the
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tree. It will also hold only that resource on return and it must
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hold that resource.
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Arguments:
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CurrentFcb - Address to store the lowest Fcb we find on this search.
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On return we will have acquired this Fcb. On entry this is the
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Fcb to examine.
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RemainingName - Supplies a buffer to store the exact case of the name being
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searched for. Initially will contain the upcase name based on the
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IgnoreCase flag.
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IgnoreCase - Indicates if we are doing a case-insensitive compare.
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Return Value:
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The Lcb used to find the current Fcb, NULL if we didn't find any prefix
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Fcbs.
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--*/
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{
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UNICODE_STRING LocalRemainingName;
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UNICODE_STRING FinalName;
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PLCB NameLink;
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PLCB CurrentLcb = NULL;
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PAGED_CODE();
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//
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// Check inputs.
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//
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ASSERT_IRP_CONTEXT( IrpContext );
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ASSERT_FCB( *CurrentFcb );
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ASSERT_EXCLUSIVE_FCB( *CurrentFcb );
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//
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// Make a local copy of the input strings.
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//
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LocalRemainingName = *RemainingName;
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//
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// Loop until we find the longest matching prefix.
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//
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while (TRUE) {
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//
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// If there are no characters left or we are not at an IndexFcb then
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// return immediately.
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//
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if ((LocalRemainingName.Length == 0) ||
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(SafeNodeType( *CurrentFcb ) != UDFS_NTC_FCB_INDEX)) {
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return CurrentLcb;
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}
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//
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// Split off the next component from the name.
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//
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UdfDissectName( IrpContext,
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&LocalRemainingName,
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&FinalName );
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//
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// Check if this name is in the splay tree for this Scb.
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//
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if (IgnoreCase) {
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NameLink = UdfFindNameLink( IrpContext,
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&(*CurrentFcb)->IgnoreCaseRoot,
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&FinalName );
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} else {
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NameLink = UdfFindNameLink( IrpContext,
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&(*CurrentFcb)->ExactCaseRoot,
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&FinalName );
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}
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//
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// If we didn't find a match then exit.
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//
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if (NameLink == NULL) {
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break;
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}
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CurrentLcb = NameLink;
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//
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// If this is a case-insensitive match then copy the exact case of the name into
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// the input buffer.
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//
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if (IgnoreCase) {
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RtlCopyMemory( FinalName.Buffer,
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NameLink->FileName.Buffer,
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NameLink->FileName.Length );
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}
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//
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// Update the caller's remaining name string to reflect the fact that we found
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// a match.
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//
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*RemainingName = LocalRemainingName;
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//
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// Move down to the next component in the tree. Acquire without waiting.
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// If this fails then lock the Fcb to reference this Fcb and then drop
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// the parent and acquire the child.
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//
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ASSERT( NameLink->ParentFcb == *CurrentFcb );
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if (!UdfAcquireFcbExclusive( IrpContext, NameLink->ChildFcb, TRUE )) {
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//
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// If we can't wait then raise CANT_WAIT.
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//
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if (!FlagOn( IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT )) {
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UdfRaiseStatus( IrpContext, STATUS_CANT_WAIT );
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}
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UdfLockVcb( IrpContext, IrpContext->Vcb );
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NameLink->ChildFcb->FcbReference += 1;
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NameLink->Reference += 1;
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UdfUnlockVcb( IrpContext, IrpContext->Vcb );
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UdfReleaseFcb( IrpContext, *CurrentFcb );
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UdfAcquireFcbExclusive( IrpContext, NameLink->ChildFcb, FALSE );
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UdfLockVcb( IrpContext, IrpContext->Vcb );
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NameLink->ChildFcb->FcbReference -= 1;
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NameLink->Reference -= 1;
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UdfUnlockVcb( IrpContext, IrpContext->Vcb );
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} else {
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UdfReleaseFcb( IrpContext, *CurrentFcb );
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}
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*CurrentFcb = NameLink->ChildFcb;
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}
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return CurrentLcb;
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}
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VOID
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UdfInitializeLcbFromDirContext (
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IN PIRP_CONTEXT IrpContext,
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IN PLCB Lcb,
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IN PDIR_ENUM_CONTEXT DirContext
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)
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/*++
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Routine Description:
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This routine performs common initialization of Lcbs from found directory
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entries.
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Arguments:
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Lcb - the Lcb to initialize.
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DirContext - the directory enumeration context, enumerated to the FID associated
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with this Lcb.
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Return Value:
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None.
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--*/
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{
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PAGED_CODE();
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//
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// Check inputs.
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//
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ASSERT_IRP_CONTEXT( IrpContext );
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ASSERT_LCB( Lcb );
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ASSERT( DirContext->Fid != NULL );
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//
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// This is falling down trivial now. Simply update the hidden flag in the Lcb.
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//
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if (FlagOn( DirContext->Fid->Flags, NSR_FID_F_HIDDEN )) {
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SetFlag( Lcb->FileAttributes, FILE_ATTRIBUTE_HIDDEN );
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}
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}
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//
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// Local support routine
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//
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PLCB
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UdfFindNameLink (
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IN PIRP_CONTEXT IrpContext,
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IN PRTL_SPLAY_LINKS *RootNode,
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IN PUNICODE_STRING Name
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)
|
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/*++
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Routine Description:
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This routine searches through a splay link tree looking for a match for the
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input name. If we find the corresponding name we will rebalance the
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tree.
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Arguments:
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RootNode - Supplies the parent to search.
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Name - This is the name to search for. Note if we are doing a case
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insensitive search the name would have been upcased already.
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Return Value:
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PLCB - The name link found or NULL if there is no match.
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--*/
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{
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FSRTL_COMPARISON_RESULT Comparison;
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PLCB Node;
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PRTL_SPLAY_LINKS Links;
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PAGED_CODE();
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Links = *RootNode;
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while (Links != NULL) {
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Node = CONTAINING_RECORD( Links, LCB, Links );
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//
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// Compare the prefix in the tree with the full name
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//
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Comparison = UdfFullCompareNames( IrpContext, &Node->FileName, Name );
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//
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// See if they don't match
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//
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if (Comparison == GreaterThan) {
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//
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// The prefix is greater than the full name
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// so we go down the left child
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//
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Links = RtlLeftChild( Links );
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//
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// And continue searching down this tree
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//
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} else if (Comparison == LessThan) {
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//
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// The prefix is less than the full name
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// so we go down the right child
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//
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Links = RtlRightChild( Links );
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//
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// And continue searching down this tree
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//
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} else {
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//
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// We found it.
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//
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// Splay the tree and save the new root.
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//
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*RootNode = RtlSplay( Links );
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return Node;
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}
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}
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//
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// We didn't find the Link.
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//
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return NULL;
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}
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//
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// Local support routine
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//
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BOOLEAN
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UdfInsertNameLink (
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IN PIRP_CONTEXT IrpContext,
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IN PRTL_SPLAY_LINKS *RootNode,
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IN PLCB NameLink
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)
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/*++
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Routine Description:
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This routine will insert a name in the splay tree pointed to
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by RootNode.
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Arguments:
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RootNode - Supplies a pointer to the table.
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NameLink - Contains the new link to enter.
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Return Value:
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BOOLEAN - TRUE if the name is inserted, FALSE otherwise.
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--*/
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{
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FSRTL_COMPARISON_RESULT Comparison;
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PLCB Node;
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PAGED_CODE();
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//
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// Check inputs.
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//
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ASSERT_IRP_CONTEXT( IrpContext );
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RtlInitializeSplayLinks( &NameLink->Links );
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//
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// If we are the first entry in the tree, just become the root.
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//
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if (*RootNode == NULL) {
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*RootNode = &NameLink->Links;
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return TRUE;
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}
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Node = CONTAINING_RECORD( *RootNode, LCB, Links );
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while (TRUE) {
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//
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// Compare the prefix in the tree with the prefix we want
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// to insert.
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//
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Comparison = UdfFullCompareNames( IrpContext, &Node->FileName, &NameLink->FileName );
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//
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// If we found the entry, return immediately.
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//
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if (Comparison == EqualTo) { return FALSE; }
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//
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// If the tree prefix is greater than the new prefix then
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// we go down the left subtree
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//
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if (Comparison == GreaterThan) {
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//
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// We want to go down the left subtree, first check to see
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// if we have a left subtree
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//
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if (RtlLeftChild( &Node->Links ) == NULL) {
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//
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// there isn't a left child so we insert ourselves as the
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// new left child
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//
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RtlInsertAsLeftChild( &Node->Links, &NameLink->Links );
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//
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// and exit the while loop
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//
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break;
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} else {
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//
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// there is a left child so simply go down that path, and
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// go back to the top of the loop
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//
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Node = CONTAINING_RECORD( RtlLeftChild( &Node->Links ),
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LCB,
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Links );
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}
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} else {
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//
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// The tree prefix is either less than or a proper prefix
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// of the new string. We treat both cases as less than when
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// we do insert. So we want to go down the right subtree,
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// first check to see if we have a right subtree
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//
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if (RtlRightChild( &Node->Links ) == NULL) {
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//
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// These isn't a right child so we insert ourselves as the
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// new right child
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//
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RtlInsertAsRightChild( &Node->Links, &NameLink->Links );
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//
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// and exit the while loop
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//
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break;
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} else {
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//
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// there is a right child so simply go down that path, and
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// go back to the top of the loop
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//
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Node = CONTAINING_RECORD( RtlRightChild( &Node->Links ),
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LCB,
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Links );
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}
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}
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}
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return TRUE;
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}
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