1069 lines
26 KiB
C
1069 lines
26 KiB
C
/*++
|
||
|
||
Copyright (c) 1991 Microsoft Corporation
|
||
|
||
Module Name:
|
||
|
||
PrefxSup.c
|
||
|
||
Abstract:
|
||
|
||
This module implements the Ntfs Prefix support routines
|
||
|
||
Author:
|
||
|
||
Gary Kimura [GaryKi] 21-May-1991
|
||
|
||
Revision History:
|
||
|
||
--*/
|
||
|
||
#include "NtfsProc.h"
|
||
|
||
//
|
||
// The Bug check file id for this module
|
||
//
|
||
|
||
#define BugCheckFileId (NTFS_BUG_CHECK_PREFXSUP)
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|
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//
|
||
// The debug trace level for this module
|
||
//
|
||
|
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#define Dbg (DEBUG_TRACE_PREFXSUP)
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||
|
||
//
|
||
// Local procedures
|
||
//
|
||
|
||
#ifdef NTFS_CHECK_SPLAY
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||
VOID
|
||
NtfsCheckSplay (
|
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IN PRTL_SPLAY_LINKS Root
|
||
);
|
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#endif
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#ifdef ALLOC_PRAGMA
|
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#pragma alloc_text(PAGE, NtfsFindPrefix)
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#pragma alloc_text(PAGE, NtfsFindNameLink)
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#pragma alloc_text(PAGE, NtfsInsertNameLink)
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#pragma alloc_text(PAGE, NtfsInsertPrefix)
|
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#pragma alloc_text(PAGE, NtfsRemovePrefix)
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|
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#ifdef NTFS_CHECK_SPLAY
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||
#pragma alloc_text(PAGE, NtfsCheckSplay)
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#endif
|
||
#endif
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||
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|
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VOID
|
||
NtfsInsertPrefix (
|
||
IN PLCB Lcb,
|
||
IN ULONG CreateFlags
|
||
)
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||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine inserts the names in the given Lcb into the links for the
|
||
parent.
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||
|
||
Arguments:
|
||
|
||
Lcb - This is the link to insert.
|
||
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||
CreateFlags - Indicates if we should insert the case-insensitive name.
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||
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Return Value:
|
||
|
||
None.
|
||
|
||
--*/
|
||
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||
{
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||
PAGED_CODE();
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ASSERT( (Lcb->Scb == NULL) ||
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NtfsIsExclusiveScb( Lcb->Scb ) );
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//
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// Attempt to insert the case-insensitive name. It is possible that
|
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// we can't enter this name.
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||
//
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||
|
||
if (FlagOn( CreateFlags, CREATE_FLAG_IGNORE_CASE )) {
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if (!FlagOn( Lcb->LcbState, LCB_STATE_IGNORE_CASE_IN_TREE ) &&
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NtfsInsertNameLink( &Lcb->Scb->ScbType.Index.IgnoreCaseNode,
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&Lcb->IgnoreCaseLink )) {
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SetFlag( Lcb->LcbState, LCB_STATE_IGNORE_CASE_IN_TREE );
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}
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} else if (!FlagOn( Lcb->LcbState, LCB_STATE_EXACT_CASE_IN_TREE )) {
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if (!NtfsInsertNameLink( &Lcb->Scb->ScbType.Index.ExactCaseNode,
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&Lcb->ExactCaseLink )) {
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NtfsBugCheck( 0, 0, 0 );
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}
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SetFlag( Lcb->LcbState, LCB_STATE_EXACT_CASE_IN_TREE );
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}
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return;
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}
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VOID
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NtfsRemovePrefix (
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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 deletes all of the Prefix entries that exist for the input
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Lcb.
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Arguments:
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Lcb - Supplies the Lcb whose prefixes are to be removed
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Return Value:
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||
None.
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||
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--*/
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{
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PAGED_CODE();
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||
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//
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// Remove the case-insensitive link.
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//
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if (FlagOn( Lcb->LcbState, LCB_STATE_IGNORE_CASE_IN_TREE )) {
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NtfsRemoveNameLink( &Lcb->Scb->ScbType.Index.IgnoreCaseNode,
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&Lcb->IgnoreCaseLink );
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ClearFlag( Lcb->LcbState, LCB_STATE_IGNORE_CASE_IN_TREE );
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}
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//
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// Now do the same for the exact case name.
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//
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if (FlagOn( Lcb->LcbState, LCB_STATE_EXACT_CASE_IN_TREE )) {
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NtfsRemoveNameLink( &Lcb->Scb->ScbType.Index.ExactCaseNode,
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&Lcb->ExactCaseLink );
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ClearFlag( Lcb->LcbState, LCB_STATE_EXACT_CASE_IN_TREE );
|
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}
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return;
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}
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PLCB
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NtfsFindPrefix (
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||
IN PIRP_CONTEXT IrpContext,
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IN PSCB StartingScb,
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OUT PFCB *CurrentFcb,
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OUT PLCB *LcbForTeardown,
|
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IN OUT UNICODE_STRING FullFileName,
|
||
IN OUT PULONG CreateFlags,
|
||
OUT PUNICODE_STRING RemainingName
|
||
)
|
||
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/*++
|
||
|
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Routine Description:
|
||
|
||
This routine begins from the given Scb 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 Scb 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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||
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Arguments:
|
||
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||
StartingScb - Supplies the Scb to start the search from.
|
||
|
||
CurrentFcb - Address to store the lowest Fcb we find on this search.
|
||
On return we will have acquired this Fcb.
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||
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LcbForTeardown - If we encounter an Lcb we must teardown on error we
|
||
store it here.
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||
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FullFileName - Supplies the input string to search for. After the search the
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buffer for this string will be modified so that for the characters that did
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match will be the exact case of what we found.
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CreateFlags - Flags for the create option - we are interested in whether
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this is a case-insensitive compare and we also will set the dos only component flag
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RemainingName - Returns the string when the prefix no longer matches.
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For example, if the input string is "alpha\beta" only matches the
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root directory then the remaining string is "alpha\beta". If the
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same string matches an LCB for "alpha" then the remaining string is
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"beta".
|
||
|
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Return Value:
|
||
|
||
PLCB - Returns a pointer to the Lcb corresponding to the longest match
|
||
in the splay tree. NULL if we didn't even find one entry.
|
||
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--*/
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{
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||
PSCB LastScb = NULL;
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PLCB LastLcb = NULL;
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PLCB ThisLcb;
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PNAME_LINK NameLink;
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UNICODE_STRING NextComponent;
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UNICODE_STRING Tail;
|
||
BOOLEAN DroppedParent;
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||
BOOLEAN NeedSnapShot = FALSE;
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||
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PAGED_CODE();
|
||
|
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//
|
||
// Start by setting the remaining name to the full name to be parsed.
|
||
//
|
||
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||
*RemainingName = FullFileName;
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//
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// If there are no characters left or the starting Scb is not an index
|
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// or the name begins with a ':' or the Fcb denotes a reparse point
|
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// then return without looking up the name.
|
||
//
|
||
|
||
if (RemainingName->Length == 0 ||
|
||
StartingScb->AttributeTypeCode != $INDEX_ALLOCATION ||
|
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RemainingName->Buffer[0] == L':' ||
|
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FlagOn( (StartingScb->Fcb)->Info.FileAttributes, FILE_ATTRIBUTE_REPARSE_POINT )) {
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return NULL;
|
||
}
|
||
|
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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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ASSERT( NtfsIsExclusiveScb( StartingScb ) );
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||
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//
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// Get the next component off of the list.
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||
//
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NtfsDissectName( *RemainingName,
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&NextComponent,
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||
&Tail );
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||
|
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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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||
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if (FlagOn( *CreateFlags, CREATE_FLAG_IGNORE_CASE )) {
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NameLink = NtfsFindNameLink( &StartingScb->ScbType.Index.IgnoreCaseNode,
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&NextComponent );
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ThisLcb = CONTAINING_RECORD( NameLink, LCB, IgnoreCaseLink );
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} else {
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NameLink = NtfsFindNameLink( &StartingScb->ScbType.Index.ExactCaseNode,
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&NextComponent );
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ThisLcb = CONTAINING_RECORD( NameLink, LCB, ExactCaseLink );
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||
}
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||
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//
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||
// If we didn't find a match then return the Fcb for the current Scb.
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||
//
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||
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||
if (NameLink == NULL) {
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||
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if (NeedSnapShot) {
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||
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//
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// NtfsCreateScb was not called on the StartingScb so take a
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||
// snapshot now.
|
||
//
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||
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||
NtfsSnapshotScb( IrpContext, StartingScb );
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||
}
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||
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return LastLcb;
|
||
}
|
||
|
||
//
|
||
// 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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||
|
||
if (FlagOn( *CreateFlags, CREATE_FLAG_IGNORE_CASE )) {
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||
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RtlCopyMemory( NextComponent.Buffer,
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ThisLcb->ExactCaseLink.LinkName.Buffer,
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NextComponent.Length );
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}
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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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||
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*RemainingName = Tail;
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||
|
||
//
|
||
// Before we give up the previous Lcb check if the name was a DOS-ONLY
|
||
// name and set the return boolean if so.
|
||
//
|
||
|
||
if (LastLcb != NULL &&
|
||
LastLcb->FileNameAttr->Flags == FILE_NAME_DOS) {
|
||
|
||
SetFlag( *CreateFlags, CREATE_FLAG_DOS_ONLY_COMPONENT );
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}
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||
|
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//
|
||
// Update the pointers to the Lcb.
|
||
//
|
||
|
||
LastLcb = ThisLcb;
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DroppedParent = FALSE;
|
||
|
||
//
|
||
// We want to acquire the next Fcb and release the one we currently
|
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// have. Try to do a fast acquire.
|
||
//
|
||
|
||
if (!NtfsAcquireFcbWithPaging( IrpContext, ThisLcb->Fcb, ACQUIRE_DONT_WAIT )) {
|
||
|
||
//
|
||
// Reference the link and Fcb so they don't go away.
|
||
//
|
||
|
||
ThisLcb->ReferenceCount += 1;
|
||
|
||
NtfsAcquireFcbTable( IrpContext, StartingScb->Vcb );
|
||
ThisLcb->Fcb->ReferenceCount += 1;
|
||
NtfsReleaseFcbTable( IrpContext, StartingScb->Vcb );
|
||
|
||
//
|
||
// Set the IrpContext to acquire paging io resources if our target
|
||
// has one. This will lock the MappedPageWriter out of this file.
|
||
//
|
||
|
||
if (ThisLcb->Fcb->PagingIoResource != NULL) {
|
||
|
||
SetFlag( IrpContext->Flags, IRP_CONTEXT_FLAG_ACQUIRE_PAGING );
|
||
}
|
||
|
||
NtfsReleaseScbWithPaging( IrpContext, StartingScb );
|
||
|
||
NtfsAcquireFcbWithPaging( IrpContext, ThisLcb->Fcb, 0 );
|
||
|
||
NtfsAcquireExclusiveScb( IrpContext, StartingScb );
|
||
ThisLcb->ReferenceCount -= 1;
|
||
NtfsReleaseScb( IrpContext, StartingScb );
|
||
|
||
NtfsAcquireFcbTable( IrpContext, StartingScb->Vcb );
|
||
ThisLcb->Fcb->ReferenceCount -= 1;
|
||
NtfsReleaseFcbTable( IrpContext, StartingScb->Vcb );
|
||
|
||
DroppedParent = TRUE;
|
||
|
||
} else {
|
||
|
||
//
|
||
// Don't forget to release the starting Scb.
|
||
//
|
||
|
||
NtfsReleaseScbWithPaging( IrpContext, StartingScb );
|
||
}
|
||
|
||
*LcbForTeardown = ThisLcb;
|
||
*CurrentFcb = ThisLcb->Fcb;
|
||
|
||
//
|
||
// It is possible that the Lcb we just found could have been removed
|
||
// from the prefix table in the window where we dropped the parent Scb.
|
||
// In that case we need to check that it is still in the prefix
|
||
// table. If not then raise CANT_WAIT to force a rescan through the
|
||
// prefix table.
|
||
//
|
||
|
||
if (DroppedParent &&
|
||
!FlagOn( ThisLcb->LcbState,
|
||
LCB_STATE_IGNORE_CASE_IN_TREE | LCB_STATE_EXACT_CASE_IN_TREE )) {
|
||
|
||
NtfsRaiseStatus( IrpContext, STATUS_CANT_WAIT, NULL, NULL );
|
||
}
|
||
|
||
//
|
||
// If we found a match but the Fcb is uninitialized or is not a directory
|
||
// then we are done. Also finished if the remaining name length is 0.
|
||
//
|
||
|
||
if (!FlagOn( ThisLcb->Fcb->FcbState, FCB_STATE_DUP_INITIALIZED ) ||
|
||
!IsDirectory( &ThisLcb->Fcb->Info ) ||
|
||
RemainingName->Length == 0) {
|
||
|
||
return LastLcb;
|
||
}
|
||
|
||
//
|
||
// Get the Scb for the $INDEX_ALLOCATION for this Fcb.
|
||
//
|
||
|
||
LastScb = StartingScb;
|
||
|
||
// Since the SCB is usually track on the end of the SCB look
|
||
// for it in the FCB first.
|
||
|
||
if (FlagOn( ThisLcb->Fcb->FcbState, FCB_STATE_COMPOUND_INDEX ) &&
|
||
(SafeNodeType( &((PFCB_INDEX) ThisLcb->Fcb)->Scb ) == NTFS_NTC_SCB_INDEX)) {
|
||
|
||
NeedSnapShot = TRUE;
|
||
|
||
StartingScb = (PSCB) &((PFCB_INDEX) ThisLcb->Fcb)->Scb;
|
||
|
||
ASSERT(!FlagOn( StartingScb->ScbState, SCB_STATE_ATTRIBUTE_DELETED) &&
|
||
(StartingScb->AttributeTypeCode == $INDEX_ALLOCATION) &&
|
||
NtfsAreNamesEqual( IrpContext->Vcb->UpcaseTable, &StartingScb->AttributeName, &NtfsFileNameIndex, FALSE ));
|
||
|
||
} else {
|
||
|
||
NeedSnapShot = FALSE;
|
||
|
||
StartingScb = NtfsCreateScb( IrpContext,
|
||
ThisLcb->Fcb,
|
||
$INDEX_ALLOCATION,
|
||
&NtfsFileNameIndex,
|
||
FALSE,
|
||
NULL );
|
||
}
|
||
|
||
//
|
||
// If there is no normalized name in this Scb, find it now.
|
||
//
|
||
|
||
if ((StartingScb->ScbType.Index.NormalizedName.Length == 0) &&
|
||
(LastScb->ScbType.Index.NormalizedName.Length != 0)) {
|
||
|
||
NtfsUpdateNormalizedName( IrpContext, LastScb, StartingScb, NULL, FALSE );
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
BOOLEAN
|
||
NtfsInsertNameLink (
|
||
IN PRTL_SPLAY_LINKS *RootNode,
|
||
IN PNAME_LINK NameLink
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine will insert a name in the splay tree pointed to
|
||
by RootNode.
|
||
|
||
The name could already exist in this tree for a case-insensitive tree.
|
||
In that case we simply return FALSE and do nothing.
|
||
|
||
Arguments:
|
||
|
||
RootNode - Supplies a pointer to the table.
|
||
|
||
NameLink - Contains the new link to enter.
|
||
|
||
Return Value:
|
||
|
||
BOOLEAN - TRUE if the name is inserted, FALSE otherwise.
|
||
|
||
--*/
|
||
|
||
{
|
||
FSRTL_COMPARISON_RESULT Comparison;
|
||
PNAME_LINK Node;
|
||
|
||
ULONG i;
|
||
ULONG MinLength;
|
||
|
||
PAGED_CODE();
|
||
|
||
RtlInitializeSplayLinks( &NameLink->Links );
|
||
|
||
//
|
||
// If we are the first entry in the tree, just become the root.
|
||
//
|
||
|
||
if (*RootNode == NULL) {
|
||
|
||
*RootNode = &NameLink->Links;
|
||
|
||
return TRUE;
|
||
}
|
||
|
||
#ifdef NTFS_CHECK_SPLAY
|
||
NtfsCheckSplay( *RootNode );
|
||
#endif
|
||
|
||
Node = CONTAINING_RECORD( *RootNode, NAME_LINK, Links );
|
||
|
||
while (TRUE) {
|
||
|
||
//
|
||
// Lets assume that we are appending to a directory and are greater than
|
||
// all entries.
|
||
//
|
||
|
||
Comparison = LessThan;
|
||
|
||
//
|
||
// If the first characters match then we need to do a full string compare.
|
||
//
|
||
|
||
if (Node->LinkName.Buffer[0] == NameLink->LinkName.Buffer[0]) {
|
||
|
||
//
|
||
// Figure out the minimum of the two lengths
|
||
//
|
||
|
||
if (Node->LinkName.Length < NameLink->LinkName.Length) {
|
||
|
||
MinLength = Node->LinkName.Length;
|
||
|
||
} else {
|
||
|
||
MinLength = NameLink->LinkName.Length;
|
||
}
|
||
|
||
//
|
||
// Loop through looking at all of the characters in both strings
|
||
// testing for equalilty, less than, and greater than
|
||
//
|
||
|
||
i = (ULONG) RtlCompareMemory( Node->LinkName.Buffer, NameLink->LinkName.Buffer, MinLength );
|
||
|
||
//
|
||
// Check if we didn't match up to the length of the shorter name.
|
||
//
|
||
|
||
if (i < MinLength) {
|
||
|
||
if (Node->LinkName.Buffer[i / sizeof( WCHAR )] > NameLink->LinkName.Buffer[i / sizeof( WCHAR )]) {
|
||
|
||
Comparison = GreaterThan;
|
||
}
|
||
|
||
//
|
||
// We match up to the length of the shorter string. If the lengths are different
|
||
// then move down the splay tree.
|
||
//
|
||
|
||
} else if (Node->LinkName.Length > NameLink->LinkName.Length) {
|
||
|
||
Comparison = GreaterThan;
|
||
|
||
//
|
||
// Exit if the strings are the same length.
|
||
//
|
||
|
||
} else if (Node->LinkName.Length == NameLink->LinkName.Length) {
|
||
|
||
return FALSE;
|
||
}
|
||
|
||
//
|
||
// Compare the first characters to figure out the comparison value.
|
||
//
|
||
|
||
} else if (Node->LinkName.Buffer[0] > NameLink->LinkName.Buffer[0]) {
|
||
|
||
Comparison = GreaterThan;
|
||
}
|
||
|
||
//
|
||
// If the tree prefix is greater than the new prefix then
|
||
// we go down the left subtree
|
||
//
|
||
|
||
if (Comparison == GreaterThan) {
|
||
|
||
//
|
||
// We want to go down the left subtree, first check to see
|
||
// if we have a left subtree
|
||
//
|
||
|
||
if (RtlLeftChild( &Node->Links ) == NULL) {
|
||
|
||
//
|
||
// there isn't a left child so we insert ourselves as the
|
||
// new left child
|
||
//
|
||
|
||
RtlInsertAsLeftChild( &Node->Links, &NameLink->Links );
|
||
|
||
//
|
||
// and exit the while loop
|
||
//
|
||
|
||
*RootNode = RtlSplay( &NameLink->Links );
|
||
|
||
break;
|
||
|
||
} else {
|
||
|
||
//
|
||
// there is a left child so simply go down that path, and
|
||
// go back to the top of the loop
|
||
//
|
||
|
||
Node = CONTAINING_RECORD( RtlLeftChild( &Node->Links ),
|
||
NAME_LINK,
|
||
Links );
|
||
}
|
||
|
||
} else {
|
||
|
||
//
|
||
// The tree prefix is either less than or a proper prefix
|
||
// of the new string. We treat both cases as less than when
|
||
// we do insert. So we want to go down the right subtree,
|
||
// first check to see if we have a right subtree
|
||
//
|
||
|
||
if (RtlRightChild( &Node->Links ) == NULL) {
|
||
|
||
//
|
||
// These isn't a right child so we insert ourselves as the
|
||
// new right child
|
||
//
|
||
|
||
RtlInsertAsRightChild( &Node->Links, &NameLink->Links );
|
||
|
||
//
|
||
// and exit the while loop
|
||
//
|
||
|
||
*RootNode = RtlSplay( &NameLink->Links );
|
||
|
||
break;
|
||
|
||
} else {
|
||
|
||
//
|
||
// there is a right child so simply go down that path, and
|
||
// go back to the top of the loop
|
||
//
|
||
|
||
Node = CONTAINING_RECORD( RtlRightChild( &Node->Links ),
|
||
NAME_LINK,
|
||
Links );
|
||
}
|
||
}
|
||
}
|
||
|
||
#ifdef NTFS_CHECK_SPLAY
|
||
NtfsCheckSplay( *RootNode );
|
||
#endif
|
||
return TRUE;
|
||
}
|
||
|
||
|
||
PNAME_LINK
|
||
NtfsFindNameLink (
|
||
IN PRTL_SPLAY_LINKS *RootNode,
|
||
IN PUNICODE_STRING Name
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This routine searches through a splay link tree looking for a match for the
|
||
input name. If we find the corresponding name we will rebalance the
|
||
tree.
|
||
|
||
Arguments:
|
||
|
||
RootNode - Supplies the parent to search.
|
||
|
||
Name - This is the name to search for. Note if we are doing a case
|
||
insensitive search the name would have been upcased already.
|
||
|
||
Return Value:
|
||
|
||
PNAME_LINK - The name link found or NULL if there is no match.
|
||
|
||
--*/
|
||
|
||
{
|
||
PNAME_LINK Node;
|
||
PRTL_SPLAY_LINKS Links;
|
||
|
||
ULONG i;
|
||
ULONG MinLength;
|
||
|
||
PAGED_CODE();
|
||
|
||
Links = *RootNode;
|
||
|
||
#ifdef NTFS_CHECK_SPLAY
|
||
if (Links != NULL) {
|
||
|
||
NtfsCheckSplay( Links );
|
||
}
|
||
#endif
|
||
|
||
while (Links != NULL) {
|
||
|
||
Node = CONTAINING_RECORD( Links, NAME_LINK, Links );
|
||
|
||
//
|
||
// If the first characters are equal then compare the full strings.
|
||
//
|
||
|
||
if (Node->LinkName.Buffer[0] == Name->Buffer[0]) {
|
||
|
||
//
|
||
// Figure out the minimum of the two lengths
|
||
//
|
||
|
||
if (Node->LinkName.Length < Name->Length) {
|
||
|
||
MinLength = Node->LinkName.Length;
|
||
|
||
} else {
|
||
|
||
MinLength = Name->Length;
|
||
}
|
||
|
||
//
|
||
// Loop through looking at all of the characters in both strings
|
||
// testing for equalilty, less than, and greater than
|
||
//
|
||
|
||
i = (ULONG) RtlCompareMemory( Node->LinkName.Buffer, Name->Buffer, MinLength );
|
||
|
||
//
|
||
// Check if we didn't match up to the length of the shorter name.
|
||
//
|
||
|
||
if (i < MinLength) {
|
||
|
||
if (Node->LinkName.Buffer[i / sizeof( WCHAR )] < Name->Buffer[i / sizeof( WCHAR )]) {
|
||
|
||
//
|
||
// The prefix is less than the full name
|
||
// so we go down the right child
|
||
//
|
||
|
||
Links = RtlRightChild( Links );
|
||
|
||
} else {
|
||
|
||
//
|
||
// The prefix is greater than the full name
|
||
// so we go down the left child
|
||
//
|
||
|
||
Links = RtlLeftChild( Links );
|
||
}
|
||
|
||
//
|
||
// We match up to the length of the shorter string. If the lengths are different
|
||
// then move down the splay tree.
|
||
//
|
||
|
||
} else if (Node->LinkName.Length < Name->Length) {
|
||
|
||
//
|
||
// The prefix is less than the full name
|
||
// so we go down the right child
|
||
//
|
||
|
||
Links = RtlRightChild( Links );
|
||
|
||
} else if (Node->LinkName.Length > Name->Length) {
|
||
|
||
//
|
||
// The prefix is greater than the full name
|
||
// so we go down the left child
|
||
//
|
||
|
||
Links = RtlLeftChild( Links );
|
||
|
||
//
|
||
// The strings are of equal lengths.
|
||
//
|
||
|
||
} else {
|
||
|
||
*RootNode = RtlSplay( Links );
|
||
|
||
#ifdef NTFS_CHECK_SPLAY
|
||
NtfsCheckSplay( *RootNode );
|
||
#endif
|
||
return Node;
|
||
}
|
||
|
||
//
|
||
// The first characters are different. Use them as a key for which
|
||
// way to branch.
|
||
//
|
||
|
||
} else if (Node->LinkName.Buffer[0] < Name->Buffer[0]) {
|
||
|
||
//
|
||
// The prefix is less than the full name
|
||
// so we go down the right child
|
||
//
|
||
|
||
Links = RtlRightChild( Links );
|
||
|
||
} else {
|
||
|
||
//
|
||
// The prefix is greater than the full name
|
||
// so we go down the left child
|
||
//
|
||
|
||
Links = RtlLeftChild( Links );
|
||
}
|
||
}
|
||
|
||
//
|
||
// We didn't find the Link.
|
||
//
|
||
|
||
return NULL;
|
||
}
|
||
|
||
|
||
|
||
//
|
||
// Local support routine
|
||
//
|
||
|
||
FSRTL_COMPARISON_RESULT
|
||
NtfsFullCompareNames (
|
||
IN PUNICODE_STRING NameA,
|
||
IN PUNICODE_STRING NameB
|
||
)
|
||
|
||
/*++
|
||
|
||
Routine Description:
|
||
|
||
This function compares two names as fast as possible. Note that since
|
||
this comparison is case sensitive we can do a direct memory comparison.
|
||
|
||
Arguments:
|
||
|
||
NameA & NameB - The names to compare.
|
||
|
||
Return Value:
|
||
|
||
COMPARISON - returns
|
||
|
||
LessThan if NameA < NameB lexicalgraphically,
|
||
GreaterThan if NameA > NameB lexicalgraphically,
|
||
EqualTo if NameA is equal to NameB
|
||
|
||
--*/
|
||
|
||
{
|
||
ULONG i;
|
||
ULONG MinLength;
|
||
|
||
PAGED_CODE();
|
||
|
||
//
|
||
// Figure out the minimum of the two lengths
|
||
//
|
||
|
||
if (NameA->Length < NameB->Length) {
|
||
|
||
MinLength = NameA->Length;
|
||
|
||
} else {
|
||
|
||
MinLength = NameB->Length;
|
||
}
|
||
|
||
//
|
||
// Loop through looking at all of the characters in both strings
|
||
// testing for equalilty, less than, and greater than
|
||
//
|
||
|
||
i = (ULONG) RtlCompareMemory( NameA->Buffer, NameB->Buffer, MinLength );
|
||
|
||
|
||
if (i < MinLength) {
|
||
|
||
return (NameA->Buffer[i / sizeof( WCHAR )] < NameB->Buffer[i / sizeof( WCHAR )] ?
|
||
LessThan :
|
||
GreaterThan);
|
||
}
|
||
|
||
if (NameA->Length < NameB->Length) {
|
||
|
||
return LessThan;
|
||
}
|
||
|
||
if (NameA->Length > NameB->Length) {
|
||
|
||
return GreaterThan;
|
||
}
|
||
|
||
return EqualTo;
|
||
}
|
||
|
||
#ifdef NTFS_CHECK_SPLAY
|
||
|
||
VOID
|
||
NtfsCheckSplay (
|
||
IN PRTL_SPLAY_LINKS Root
|
||
)
|
||
|
||
{
|
||
PRTL_SPLAY_LINKS Current;
|
||
|
||
PAGED_CODE();
|
||
|
||
Current = Root;
|
||
|
||
//
|
||
// Root must point to itself.
|
||
//
|
||
|
||
if (Current->Parent != Current) {
|
||
|
||
KdPrint(("NTFS: Bad splay root\n", 0));
|
||
DbgBreakPoint();
|
||
}
|
||
|
||
goto LeftChild;
|
||
while (TRUE) {
|
||
|
||
LeftChild:
|
||
|
||
//
|
||
// If there is a left child then verify it.
|
||
//
|
||
|
||
if (Current->LeftChild != NULL) {
|
||
|
||
//
|
||
// The child can't point to itself and
|
||
// the current node must be the parent of the
|
||
// child.
|
||
//
|
||
|
||
if ((Current->LeftChild == Current) ||
|
||
(Current->LeftChild->Parent != Current)) {
|
||
|
||
KdPrint(("NTFS: Bad left child\n", 0));
|
||
DbgBreakPoint();
|
||
}
|
||
|
||
//
|
||
// Go to the left child and verify it.
|
||
//
|
||
|
||
Current = Current->LeftChild;
|
||
goto LeftChild;
|
||
}
|
||
|
||
//
|
||
// If there is no left child then check for a right child.
|
||
//
|
||
|
||
goto RightChild;
|
||
|
||
RightChild:
|
||
|
||
//
|
||
// If there is a right child then verify it.
|
||
//
|
||
|
||
if (Current->RightChild != NULL) {
|
||
|
||
//
|
||
// The child can't point to itself and
|
||
// the current node must be the parent of the
|
||
// child.
|
||
//
|
||
|
||
if ((Current->RightChild == Current) ||
|
||
(Current->RightChild->Parent != Current)) {
|
||
|
||
KdPrint(("NTFS: Bad Right child\n", 0));
|
||
DbgBreakPoint();
|
||
}
|
||
|
||
//
|
||
// Go to the right child and verify it. We always
|
||
// start in the left child of a new node.
|
||
//
|
||
|
||
Current = Current->RightChild;
|
||
goto LeftChild;
|
||
}
|
||
|
||
//
|
||
// There is no right child. If we are a right child then move up to
|
||
// the parent and keep going until we reach the root or reach a left child.
|
||
//
|
||
|
||
goto Parent;
|
||
|
||
Parent:
|
||
|
||
//
|
||
// We may be in the root now.
|
||
//
|
||
|
||
if (Current == Root) {
|
||
|
||
return;
|
||
}
|
||
|
||
//
|
||
// If we are a left child then go to the parent and look for a right child.
|
||
//
|
||
|
||
if (Current == Current->Parent->LeftChild) {
|
||
|
||
Current = Current->Parent;
|
||
goto RightChild;
|
||
}
|
||
|
||
//
|
||
// We are a right child. Go to the parent and check again.
|
||
//
|
||
|
||
Current = Current->Parent;
|
||
goto Parent;
|
||
}
|
||
}
|
||
#endif
|
||
|