/*++
Copyright (c) 1996-2000 Microsoft Corporation
Module Name:
DirSup.c
Abstract:
This module implements the support for walking across on-disk directory
structures.
// @@BEGIN_DDKSPLIT
Author:
Dan Lovinger [DanLo] 11-Jun-1996
Revision History:
// @@END_DDKSPLIT
--*/
#include "UdfProcs.h"
//
// The Bug check file id for this module
//
#define BugCheckFileId (UDFS_BUG_CHECK_DIRSUP)
//
// The local debug trace level
//
#define Dbg (UDFS_DEBUG_LEVEL_DIRSUP)
//
// Local support routines.
//
BOOLEAN
UdfLookupDirEntryPostProcessing (
IN PIRP_CONTEXT IrpContext,
IN PFCB Fcb,
IN PDIR_ENUM_CONTEXT DirContext,
IN BOOLEAN ReturnError
);
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, UdfCleanupDirContext)
#pragma alloc_text(PAGE, UdfFindDirEntry)
#pragma alloc_text(PAGE, UdfInitializeDirContext)
#pragma alloc_text(PAGE, UdfLookupDirEntryPostProcessing)
#pragma alloc_text(PAGE, UdfLookupInitialDirEntry)
#pragma alloc_text(PAGE, UdfLookupNextDirEntry)
#pragma alloc_text(PAGE, UdfUpdateDirNames)
#endif
VOID
UdfInitializeDirContext (
IN PIRP_CONTEXT IrpContext,
IN PDIR_ENUM_CONTEXT DirContext
)
/*++
Routine Description:
This routine initializes a directory enumeartion context.
Call this exactly once in the lifetime of a context.
Arguments:
DirContext - a context to initialize
Return Value:
None.
--*/
{
//
// Check inputs.
//
ASSERT_IRP_CONTEXT( IrpContext );
//
// Provide defaults for fields, nothing too special.
//
RtlZeroMemory( DirContext, sizeof(DIR_ENUM_CONTEXT) );
}
VOID
UdfCleanupDirContext (
IN PIRP_CONTEXT IrpContext,
IN PDIR_ENUM_CONTEXT DirContext
)
/*++
Routine Description:
This routine cleans up a directory enumeration context for reuse.
Arguments:
DirContext - a context to clean.
Return Value:
None.
--*/
{
PAGED_CODE();
//
// Check input.
//
ASSERT_IRP_CONTEXT( IrpContext );
//
// Dump the allocation we store the triple of names in.
//
UdfFreePool( &DirContext->NameBuffer );
//
// And the short name.
//
UdfFreePool( &DirContext->ShortObjectName.Buffer );
//
// Unpin the view.
//
UdfUnpinData( IrpContext, &DirContext->Bcb );
//
// Free a buffered Fid that may remain.
//
if (FlagOn( DirContext->Flags, DIR_CONTEXT_FLAG_FID_BUFFERED )) {
UdfFreePool( &DirContext->Fid );
}
//
// Zero everything else out.
//
RtlZeroMemory( DirContext, sizeof( DIR_ENUM_CONTEXT ) );
}
BOOLEAN
UdfLookupInitialDirEntry (
IN PIRP_CONTEXT IrpContext,
IN PFCB Fcb,
IN PDIR_ENUM_CONTEXT DirContext,
IN PLONGLONG InitialOffset OPTIONAL
)
/*++
Routine Description:
This routine begins the enumeration of a directory by setting the context
at the first avaliable directory entry.
Arguments:
Fcb - the directory being enumerated.
DirContext - a corresponding context for the enumeration.
InitialOffset - an optional starting byte offset to base the enumeration.
Return Value:
If InitialOffset is unspecified, TRUE will always be returned. Failure will result
in a raised status indicating corruption.
If InitialOffset is specified, TRUE will be returned if a valid entry is found at this
offset, FALSE otherwise.
--*/
{
BOOLEAN Result;
PAGED_CODE();
//
// Check inputs.
//
ASSERT_IRP_CONTEXT( IrpContext );
ASSERT_FCB_INDEX( Fcb );
//
// Create the internal stream if it isn't already in place.
//
if (Fcb->FileObject == NULL) {
UdfCreateInternalStream( IrpContext, Fcb->Vcb, Fcb );
}
//
// Reset the flags.
//
DirContext->Flags = 0;
if (InitialOffset) {
//
// If we are beginning in the middle of the stream, adjust the sanity check flags.
//
if (*InitialOffset != 0) {
DirContext->Flags = DIR_CONTEXT_FLAG_SEEN_NONCONSTANT | DIR_CONTEXT_FLAG_SEEN_PARENT;
}
//
// Now set up the range we will map. This is constrained by the size of a cache view.
//
DirContext->BaseOffset.QuadPart = GenericTruncate( *InitialOffset, VACB_MAPPING_GRANULARITY );
DirContext->ViewOffset = (ULONG) GenericOffset( *InitialOffset, VACB_MAPPING_GRANULARITY );
} else {
//
// Map at the beginning.
//
DirContext->BaseOffset.QuadPart = 0;
DirContext->ViewOffset = 0;
}
//
// Contain the view length by the size of the stream and map.
//
DirContext->ViewLength = VACB_MAPPING_GRANULARITY;
if (DirContext->BaseOffset.QuadPart + DirContext->ViewLength > Fcb->FileSize.QuadPart) {
DirContext->ViewLength = (ULONG) (Fcb->FileSize.QuadPart - DirContext->BaseOffset.QuadPart);
}
UdfUnpinData( IrpContext, &DirContext->Bcb );
CcMapData( Fcb->FileObject,
&DirContext->BaseOffset,
DirContext->ViewLength,
TRUE,
&DirContext->Bcb,
&DirContext->View );
DirContext->Fid = Add2Ptr( DirContext->View, DirContext->ViewOffset, PNSR_FID );
//
// The state of the context is now valid. Tail off into our common post-processor
// to finish the work.
//
return UdfLookupDirEntryPostProcessing( IrpContext,
Fcb,
DirContext,
(BOOLEAN) (InitialOffset != NULL));
}
BOOLEAN
UdfLookupNextDirEntry (
IN PIRP_CONTEXT IrpContext,
IN PFCB Fcb,
IN PDIR_ENUM_CONTEXT DirContext
)
/*++
Routine Description:
This routine advances the enumeration of a directory by one entry.
Arguments:
Fcb - the directory being enumerated.
DirContext - a corresponding context for the enumeration.
Return Value:
BOOLEAN True if another Fid is avaliable, False if we are at the end.
--*/
{
PAGED_CODE();
//
// Check inputs.
//
ASSERT_IRP_CONTEXT( IrpContext );
ASSERT_FCB_INDEX( Fcb );
//
// If we have reached the end, stop.
//
if (DirContext->BaseOffset.QuadPart + DirContext->NextFidOffset == Fcb->FileSize.QuadPart) {
return FALSE;
}
//
// If the previous Fid was buffered, dismantle it now.
//
if (FlagOn( DirContext->Flags, DIR_CONTEXT_FLAG_FID_BUFFERED )) {
ClearFlag( DirContext->Flags, DIR_CONTEXT_FLAG_FID_BUFFERED );
UdfFreePool( &DirContext->Fid );
}
//
// Move the pointers based on the knowledge generated in the previous iteration.
//
DirContext->ViewOffset = DirContext->NextFidOffset;
DirContext->Fid = Add2Ptr( DirContext->View, DirContext->ViewOffset, PNSR_FID );
//
// The state of the context is now valid. Tail off into our common post-processor
// to finish the work.
//
return UdfLookupDirEntryPostProcessing( IrpContext,
Fcb,
DirContext,
FALSE );
}
VOID
UdfUpdateDirNames (
IN PIRP_CONTEXT IrpContext,
IN PDIR_ENUM_CONTEXT DirContext,
IN BOOLEAN IgnoreCase
)
/*++
Routine Description:
This routine fills in the non-short names of a directory enumeration context
for the Fid currently referenced.
Arguments:
DirContext - a corresponding context to fill in.
IgnoreCase - whether the caller wants to be insensitive to case.
Return Value:
None.
--*/
{
PUCHAR NameDstring;
BOOLEAN ContainsIllegal;
USHORT NameLength;
USHORT RequiredBufferLength;
USHORT PresentLength;
PAGED_CODE();
//
// Check input.
//
ASSERT_IRP_CONTEXT( IrpContext );
DebugTrace(( +1, Dbg, "UdfUpdateDirNames\n" ));
//
// Handle the case of the self directory entry.
//
if (DirContext->Fid == NULL) {
//
// Simply synthesize
//
//
// It doesn't hurt to be pedantic about initialization, so do it all.
//
DirContext->PureObjectName.Length =
DirContext->CaseObjectName.Length =
DirContext->ObjectName.Length = UdfUnicodeDirectoryNames[SELF_ENTRY].Length;
DirContext->PureObjectName.MaximumLength =
DirContext->CaseObjectName.MaximumLength =
DirContext->ObjectName.MaximumLength = UdfUnicodeDirectoryNames[SELF_ENTRY].MaximumLength;
DirContext->PureObjectName.Buffer =
DirContext->CaseObjectName.Buffer =
DirContext->ObjectName.Buffer = UdfUnicodeDirectoryNames[SELF_ENTRY].Buffer;
//
// All done.
//
DebugTrace(( 0, Dbg, "Self Entry case\n" ));
DebugTrace(( -1, Dbg, "UdfUpdateDirNames -> VOID\n" ));
return;
}
//
// Handle the case of the parent directory entry.
//
if (FlagOn( DirContext->Fid->Flags, NSR_FID_F_PARENT )) {
//
// Parent entries must occur at the front of the directory and
// have a fid length of zero (13346 4/14.4.4).
//
if (FlagOn( DirContext->Flags, DIR_CONTEXT_FLAG_SEEN_NONCONSTANT ) ||
DirContext->Fid->FileIDLen != 0) {
UdfRaiseStatus( IrpContext, STATUS_FILE_CORRUPT_ERROR );
}
//
// Note that we have seen the parent entry.
//
SetFlag( DirContext->Flags, DIR_CONTEXT_FLAG_SEEN_PARENT );
//
// It doesn't hurt to be pedantic about initialization, so do it all.
//
DirContext->PureObjectName.Length =
DirContext->CaseObjectName.Length =
DirContext->ObjectName.Length = UdfUnicodeDirectoryNames[PARENT_ENTRY].Length;
DirContext->PureObjectName.MaximumLength =
DirContext->CaseObjectName.MaximumLength =
DirContext->ObjectName.MaximumLength = UdfUnicodeDirectoryNames[PARENT_ENTRY].MaximumLength;
DirContext->PureObjectName.Buffer =
DirContext->CaseObjectName.Buffer =
DirContext->ObjectName.Buffer = UdfUnicodeDirectoryNames[PARENT_ENTRY].Buffer;
//
// All done.
//
DebugTrace(( 0, Dbg, "Parent Entry case\n" ));
DebugTrace(( -1, Dbg, "UdfUpdateDirNames -> VOID\n" ));
return;
}
//
// We now know that we will need to convert the name in a real FID, so figure out where
// it sits in the descriptor.
//
NameDstring = Add2Ptr( DirContext->Fid, ISONsrFidConstantSize + DirContext->Fid->ImpUseLen, PUCHAR );
//
// Every directory must record a parent entry.
//
if (!FlagOn( DirContext->Flags, DIR_CONTEXT_FLAG_SEEN_PARENT)) {
UdfRaiseStatus( IrpContext, STATUS_FILE_CORRUPT_ERROR );
}
//
// Note that we are proceeding into the non-constant portion of a directory.
//
SetFlag( DirContext->Flags, DIR_CONTEXT_FLAG_SEEN_NONCONSTANT );
//
// Make sure the dstring is good CS0
//
UdfCheckLegalCS0Dstring( IrpContext,
NameDstring,
DirContext->Fid->FileIDLen,
0,
FALSE );
//
// Don't bother allocating tiny buffers - always make sure we get enough for an 8.3 name.
//
RequiredBufferLength =
NameLength = Max( BYTE_COUNT_8_DOT_3, UdfCS0DstringUnicodeSize( IrpContext,
NameDstring,
DirContext->Fid->FileIDLen) );
//
// Illegality is both actual illegal characters and too many characters.
//
ContainsIllegal = (!UdfCS0DstringIsLegalFileName( NameDstring, DirContext->Fid->FileIDLen ) ||
(NameLength / sizeof( WCHAR )) > MAX_LEN);
//
// If we're illegal, we will need more characters to hold the uniqifying stamp.
//
if (ContainsIllegal) {
RequiredBufferLength = (NameLength += (CRC_LEN * sizeof(WCHAR)));
}
//
// If we need to build a case insensitive name, need more space.
//
if (IgnoreCase) {
RequiredBufferLength += NameLength;
}
//
// If we need to render the names due to illegal characters, more space again.
//
if (ContainsIllegal) {
RequiredBufferLength += NameLength;
} else {
//
// Make sure the names aren't seperated. If more illegal names are found we can
// resplit the buffer but until then avoid the expense of having to copy bytes
// ... odds are that illegal characters are going to be a rarish occurance.
//
DirContext->PureObjectName.Buffer = DirContext->ObjectName.Buffer;
}
//
// We expect the name lengths and hence buffer size to be multiple of WCHAR
//
ASSERT( 0 == (RequiredBufferLength & 1));
DebugTrace(( 0, Dbg,
"Ob %s%sneeds %d bytes (%d byte chunks), have %d\n",
(IgnoreCase? "Ic " : ""),
(ContainsIllegal? "Ci " : ""),
RequiredBufferLength,
NameLength,
DirContext->AllocLength ));
//
// Check if we need more space for the names. We will need more if the name size is greater
// than the maximum we can currently store, or if we have stumbled across illegal characters
// and the current Pure name is not seperated from the exposed Object name.
//
// Note that IgnoreCase remains constant across usage of a context so we don't have to wonder
// if it has been seperated from the ObjectName - it'll always be correct.
//
if ((NameLength > DirContext->ObjectName.MaximumLength) ||
(ContainsIllegal && (DirContext->ObjectName.Buffer == DirContext->PureObjectName.Buffer))) {
USHORT DividedBufferLength = 0;
DebugTrace(( 0, Dbg, "Resizing buffers\n" ));
//
// Figure out if we can break up the current allocation in a different way before falling
// back to a new allocation. Ensure we use even byte size chunks, or else we can land
// up with alignment faults on IA64.
//
if (DirContext->AllocLength >= RequiredBufferLength) {
DividedBufferLength = (DirContext->AllocLength / (1 +
(IgnoreCase? 1 : 0) +
(ContainsIllegal? 1 : 0))) & ~(USHORT)1;
}
if (DividedBufferLength >= NameLength) {
//
// So we can still use the current allocation, re-divided.
//
DirContext->PureObjectName.MaximumLength =
DirContext->CaseObjectName.MaximumLength =
DirContext->ObjectName.MaximumLength = DividedBufferLength;
DebugTrace(( 0, Dbg,
"... by resplit into %d byte chunks\n",
DirContext->ObjectName.MaximumLength ));
//
// Set the buffer pointers up. Required adjustment will occur below.
//
DirContext->PureObjectName.Buffer =
DirContext->CaseObjectName.Buffer =
DirContext->ObjectName.Buffer = DirContext->NameBuffer;
} else {
DebugTrace(( 0, Dbg, "... by allocating new pool\n" ));
//
// Oh well, no choice but to fall back into the pool. Drop our previous hunk.
//
UdfFreePool( &DirContext->NameBuffer );
DirContext->AllocLength = 0;
//
// The names share an allocation for efficiency.
//
DirContext->PureObjectName.MaximumLength =
DirContext->CaseObjectName.MaximumLength =
DirContext->ObjectName.MaximumLength = NameLength;
DirContext->NameBuffer =
DirContext->PureObjectName.Buffer =
DirContext->CaseObjectName.Buffer =
DirContext->ObjectName.Buffer = FsRtlAllocatePoolWithTag( UdfPagedPool,
RequiredBufferLength,
TAG_FILE_NAME );
DirContext->AllocLength = RequiredBufferLength;
}
//
// In the presence of the "as appropriate" names, adjust the buffer locations. Note
// that ObjectName.Buffer is always the base of the allocated space.
//
if (IgnoreCase) {
DirContext->CaseObjectName.Buffer = Add2Ptr( DirContext->ObjectName.Buffer,
DirContext->ObjectName.MaximumLength,
PWCHAR );
}
if (ContainsIllegal) {
DirContext->PureObjectName.Buffer = Add2Ptr( DirContext->CaseObjectName.Buffer,
DirContext->CaseObjectName.MaximumLength,
PWCHAR );
}
}
ASSERT( RequiredBufferLength <= DirContext->AllocLength );
//
// Convert the dstring.
//
UdfConvertCS0DstringToUnicode( IrpContext,
NameDstring,
DirContext->Fid->FileIDLen,
0,
&DirContext->PureObjectName );
//
// If illegal characters were present, run the name through the UDF transmogrifier.
//
if (ContainsIllegal) {
UdfRenderNameToLegalUnicode( IrpContext,
&DirContext->PureObjectName,
&DirContext->ObjectName );
//
// The ObjectName is the same as the PureObjectName.
//
} else {
DirContext->ObjectName.Length = DirContext->PureObjectName.Length;
}
//
// Upcase the result if required.
//
if (IgnoreCase) {
UdfUpcaseName( IrpContext,
&DirContext->ObjectName,
&DirContext->CaseObjectName );
}
DebugTrace(( -1, Dbg, "UdfUpdateDirNames -> VOID\n" ));
return;
}
BOOLEAN
UdfFindDirEntry (
IN PIRP_CONTEXT IrpContext,
IN PFCB Fcb,
IN PUNICODE_STRING Name,
IN BOOLEAN IgnoreCase,
IN BOOLEAN ShortName,
IN PDIR_ENUM_CONTEXT DirContext
)
/*++
Routine Description:
This routine walks the directory specified for an entry which matches the input
criteria.
Arguments:
Fcb - the directory to search
Name - name to search for
IgnoreCase - whether this search should be case-insensitive (Name will already
be upcased)
ShortName - whether the name should be searched for according to short name rules
DirContext - context structure to use and return results in
Return Value:
BOOLEAN True if a matching directory entry is being returned, False otherwise.
--*/
{
PUNICODE_STRING MatchName;
PAGED_CODE();
//
// Check inputs.
//
ASSERT_IRP_CONTEXT( IrpContext );
ASSERT_FCB_INDEX( Fcb );
DebugTrace(( +1, Dbg,
"UdfFindDirEntry, Fcb=%08x Name=\"%wZ\" Ignore=%u Short=%u, DC=%08x\n",
Fcb,
Name,
IgnoreCase,
ShortName,
DirContext ));
//
// Depending on the kind of search we are performing a different flavor of the found name
// wil be used in the comparison.
//
if (ShortName) {
MatchName = &DirContext->ShortObjectName;
} else {
MatchName = &DirContext->CaseObjectName;
}
//
// Go get the first entry.
//
UdfLookupInitialDirEntry( IrpContext,
Fcb,
DirContext,
NULL );
//
// Now loop looking for a good match.
//
do {
//
// If it is deleted, we obviously aren't interested in it.
//
if (FlagOn( DirContext->Fid->Flags, NSR_FID_F_DELETED )) {
continue;
}
UdfUpdateDirNames( IrpContext,
DirContext,
IgnoreCase );
//
// If this is a constant entry, just keep going.
//
if (!FlagOn( DirContext->Flags, DIR_CONTEXT_FLAG_SEEN_NONCONSTANT )) {
continue;
}
DebugTrace(( 0, Dbg,
"\"%wZ\" (pure \"%wZ\") @ +%08x\n",
&DirContext->ObjectName,
&DirContext->PureObjectName,
DirContext->ViewOffset ));
//
// If we are searching for generated shortnames, a small subset of the names
// in the directory are actually candidates for a match. Go get the name.
//
if (ShortName) {
//
// Now, only if this Fid's name is non 8.3 is it neccesary to work with it.
//
if (!UdfIs8dot3Name( IrpContext, DirContext->ObjectName )) {
//
// Allocate the shortname if it isn't already done.
//
if (DirContext->ShortObjectName.Buffer == NULL) {
DirContext->ShortObjectName.Buffer = FsRtlAllocatePoolWithTag( UdfPagedPool,
BYTE_COUNT_8_DOT_3,
TAG_SHORT_FILE_NAME );
DirContext->ShortObjectName.MaximumLength = BYTE_COUNT_8_DOT_3;
}
UdfGenerate8dot3Name( IrpContext,
&DirContext->PureObjectName,
&DirContext->ShortObjectName );
DebugTrace(( 0, Dbg,
"built shortname \"%wZ\"\n", &DirContext->ShortObjectName ));
} else {
//
// As an 8.3 name already, this name will not have caused us to have to generate
// a short name, so it can't be the case that the caller is looking for it.
//
continue;
}
}
if (UdfFullCompareNames( IrpContext,
MatchName,
Name ) == EqualTo) {
//
// Got a match, so give it up.
//
DebugTrace(( 0, Dbg, "HIT\n" ));
DebugTrace(( -1, Dbg, "UdfFindDirEntry -> TRUE\n" ));
return TRUE;
}
} while ( UdfLookupNextDirEntry( IrpContext,
Fcb,
DirContext ));
//
// No match was found.
//
DebugTrace(( -1, Dbg, "UdfFindDirEntry -> FALSE\n" ));
return FALSE;
}
//
// Local support routine
//
BOOLEAN
UdfLookupDirEntryPostProcessing (
IN PIRP_CONTEXT IrpContext,
IN PFCB Fcb,
IN PDIR_ENUM_CONTEXT DirContext,
IN BOOLEAN ReturnError
)
/*++
Routine Description:
This routine is the core engine of directory stream enumeration. It receives
a context which has been advanced and does the integrity checks and final
extraction of the Fid with respect to file cache granularity restrictions.
NOTE: we assume that a Fid cannot span a cache view. The maximum size of a
Fid is just over 32k, so this is a good and likely permanent assumption.
Arguments:
Fcb - the directory being enumerated.
DirContext - a corresponding context for the enumeration.
ReturnError - whether errors should be returned (or raised)
Return Value:
BOOLEAN according to the successful extraction of the Fid. If ReturnError is
FALSE, then failure will result in a raised status.
--*/
{
BOOLEAN Result = TRUE;
PNSR_FID FidBufferC = NULL;
PNSR_FID FidBuffer = NULL;
PNSR_FID FidC;
PNSR_FID Fid;
ULONG FidSize;
ULONG FidBytesInPreviousView = 0;
PAGED_CODE();
//
// Check inputs.
//
ASSERT_IRP_CONTEXT( IrpContext );
ASSERT_FCB_INDEX( Fcb );
try {
//
// First check that the stream can contain another FID.
//
if (DirContext->BaseOffset.QuadPart +
DirContext->ViewOffset +
ISONsrFidConstantSize > Fcb->FileSize.QuadPart) {
DebugTrace(( 0, Dbg,
"UdfLookupDirEntryPostProcessing: DC %p, constant header overlaps end of dir\n",
DirContext ));
try_leave( Result = FALSE );
}
//
// We now build up the constant portion of the FID for use. It may be the case that
// this spans a view boundary and must be buffered, or is entirely in the next view
// and we simply need to advance.
//
if (GenericTruncatePtr( Add2Ptr( DirContext->Fid, ISONsrFidConstantSize - 1, PUCHAR ), VACB_MAPPING_GRANULARITY ) !=
DirContext->View) {
FidBytesInPreviousView = GenericRemainderPtr( DirContext->Fid, VACB_MAPPING_GRANULARITY );
//
// Only buffer if there are really bytes in the previous view.
//
if (FidBytesInPreviousView) {
FidC =
FidBufferC = FsRtlAllocatePoolWithTag( UdfPagedPool,
ISONsrFidConstantSize,
TAG_FID_BUFFER );
RtlCopyMemory( FidBufferC,
DirContext->Fid,
FidBytesInPreviousView );
}
//
// Now advance into the next view to pick up the rest.
//
DirContext->BaseOffset.QuadPart += VACB_MAPPING_GRANULARITY;
DirContext->ViewOffset = 0;
//
// Contain the view length by the size of the stream and map.
//
DirContext->ViewLength = VACB_MAPPING_GRANULARITY;
if (DirContext->BaseOffset.QuadPart + DirContext->ViewLength > Fcb->FileSize.QuadPart) {
DirContext->ViewLength = (ULONG) (Fcb->FileSize.QuadPart - DirContext->BaseOffset.QuadPart);
}
UdfUnpinData( IrpContext, &DirContext->Bcb );
CcMapData( Fcb->FileObject,
&DirContext->BaseOffset,
DirContext->ViewLength,
TRUE,
&DirContext->Bcb,
&DirContext->View );
//
// We are guaranteed that this much lies in the stream. Build the rest of the
// constant header.
//
if (FidBytesInPreviousView) {
RtlCopyMemory( Add2Ptr( FidBufferC, FidBytesInPreviousView, PUCHAR ),
DirContext->View,
ISONsrFidConstantSize - FidBytesInPreviousView );
//
// In fact, this FID is perfectly aligned to the front of this view. No buffering
// is required, and we just set the FID pointer.
//
} else {
DirContext->Fid = DirContext->View;
}
}
//
// If no buffering was required, we can use the cache directly.
//
if (!FidBytesInPreviousView) {
FidC = DirContext->Fid;
}
//
// Now we can check that the Fid data lies within the stream bounds and is sized
// within a logical block (per UDF). This will complete the size-wise integrity
// verification.
//
if (((DirContext->BaseOffset.QuadPart +
DirContext->ViewOffset -
FidBytesInPreviousView +
ISONsrFidSize( FidC ) > Fcb->FileSize.QuadPart) &&
DebugTrace(( 0, Dbg,
"UdfLookupDirEntryPostProcessing: DC %p, FID (FidC %p, FBIPV %u) overlaps end of dir\n",
DirContext,
FidC,
FidBytesInPreviousView )))
||
(ISONsrFidSize( FidC ) > BlockSize( Fcb->Vcb ) &&
DebugTrace(( 0, Dbg,
"UdfLookupDirEntryPostProcessing: DC %p, FID (FidC %p) larger than a logical block\n",
DirContext,
FidC )))) {
try_leave( Result = FALSE );
}
//
// Final Fid rollup.
//
//
// The Fid may span a view boundary and should be buffered. If we already buffered, we know
// we have to do this.
//
if (FidBytesInPreviousView ||
GenericTruncatePtr( Add2Ptr( DirContext->Fid, ISONsrFidSize( FidC ) - 1, PUCHAR ), VACB_MAPPING_GRANULARITY ) !=
DirContext->View) {
Fid =
FidBuffer = FsRtlAllocatePoolWithTag( UdfPagedPool,
ISONsrFidSize( FidC ),
TAG_FID_BUFFER );
//
// Pull the fidsize out now in case we're still pointing to the cache (ie. no
// buffering was required for fixed portion) but are about to change the mapping
// below (need to buffer for variable portion).
//
FidSize = ISONsrFidSize( FidC);
//
// If we already buffered and advanced for the header, just prefill
// the final Fid buffer with the bytes that are now unavaliable.
//
if (FidBytesInPreviousView) {
RtlCopyMemory( FidBuffer,
FidBufferC,
FidBytesInPreviousView );
} else {
//
// Buffer and advance the view.
//
FidBytesInPreviousView = GenericRemainderPtr( DirContext->Fid, VACB_MAPPING_GRANULARITY );
RtlCopyMemory( FidBuffer,
DirContext->Fid,
FidBytesInPreviousView );
//
// Now advance into the next view to pick up the rest.
//
DirContext->BaseOffset.QuadPart += VACB_MAPPING_GRANULARITY;
DirContext->ViewOffset = 0;
//
// Contain the view length by the size of the stream and map.
//
DirContext->ViewLength = VACB_MAPPING_GRANULARITY;
if (DirContext->BaseOffset.QuadPart + DirContext->ViewLength > Fcb->FileSize.QuadPart) {
DirContext->ViewLength = (ULONG) (Fcb->FileSize.QuadPart - DirContext->BaseOffset.QuadPart);
}
UdfUnpinData( IrpContext, &DirContext->Bcb );
CcMapData( Fcb->FileObject,
&DirContext->BaseOffset,
DirContext->ViewLength,
TRUE,
&DirContext->Bcb,
&DirContext->View );
}
//
// We are guaranteed that this much lies in the stream.
//
RtlCopyMemory( Add2Ptr( FidBuffer, FidBytesInPreviousView, PUCHAR ),
DirContext->View,
FidSize - FidBytesInPreviousView );
} else {
Fid = DirContext->Fid;
}
//
// We finally have the whole Fid safely extracted from the cache, so the
// integrity check is now the last step before success. For simplicity's
// sake we trust the Lbn field.
//
Result = UdfVerifyDescriptor( IrpContext,
&Fid->Destag,
DESTAG_ID_NSR_FID,
ISONsrFidSize( Fid ),
Fid->Destag.Lbn,
ReturnError );
//
// Prepare to return a buffered Fid.
//
if (FidBuffer && Result) {
SetFlag( DirContext->Flags, DIR_CONTEXT_FLAG_FID_BUFFERED );
DirContext->Fid = FidBuffer;
FidBuffer = NULL;
}
} finally {
UdfFreePool( &FidBuffer );
UdfFreePool( &FidBufferC );
}
if (!ReturnError && !Result) {
UdfRaiseStatus( IrpContext, STATUS_FILE_CORRUPT_ERROR );
}
//
// On success update the next Fid information in the context.
// Note that we must drop in a hint as to where the next Fid
// will be found so that the next advance will know how much
// of a buffered Fid isn't in this view.
//
if (Result) {
DirContext->NextFidOffset = DirContext->ViewOffset +
ISONsrFidSize( Fid );
if (FidBytesInPreviousView) {
DirContext->NextFidOffset -= FidBytesInPreviousView;
}
}
return Result;
}