242 lines
4.6 KiB
C
242 lines
4.6 KiB
C
/*++
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Copyright (c) 1989 Microsoft Corporation
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Module Name:
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FilObSup.c
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Abstract:
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This module implements the Udfs File object support routines.
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Author:
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Dan Lovinger [DanLo] 23-Sep-1996
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Revision History:
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--*/
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#include "UdfProcs.h"
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// The Bug check file id for this module
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#define BugCheckFileId (UDFS_BUG_CHECK_FILOBSUP)
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// The local debug trace level
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#define Dbg (UDFS_DEBUG_LEVEL_FILOBSUP)
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// Local constants.
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#define TYPE_OF_OPEN_MASK (0x00000007)
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text(PAGE, UdfDecodeFileObject)
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#pragma alloc_text(PAGE, UdfFastDecodeFileObject)
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#pragma alloc_text(PAGE, UdfSetFileObject)
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#endif
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VOID
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UdfSetFileObject (
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IN PIRP_CONTEXT IrpContext,
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IN PFILE_OBJECT FileObject,
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IN TYPE_OF_OPEN TypeOfOpen,
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IN PFCB Fcb OPTIONAL,
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IN PCCB Ccb OPTIONAL
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)
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/*++
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Routine Description:
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This routine will initialize the FileObject context fields based on the
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input type and data structures.
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Arguments:
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FileObject - Supplies the file object pointer being initialized.
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TypeOfOpen - Sets the type of open.
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Fcb - Fcb for this file object. Ignored for UnopenedFileObject.
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Ccb - Ccb for the handle corresponding to this file object. Will not
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be present for stream file objects.
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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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// We only have values 0 to 7 available so make sure we didn't
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// inadvertantly add a new type.
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ASSERTMSG( "FileObject types exceed available bits\n", BeyondValidType <= 8 );
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// Setting a file object to type UnopenedFileObject means just
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// clearing all of the context fields. All the other input
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if (TypeOfOpen == UnopenedFileObject) {
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FileObject->FsContext =
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FileObject->FsContext2 = NULL;
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return;
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}
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// Check that the 3 low-order bits of the Ccb are clear.
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ASSERTMSG( "Ccb is not quad-aligned\n", !FlagOn( ((ULONG_PTR) Ccb), TYPE_OF_OPEN_MASK ));
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// We will or the type of open into the low order bits of FsContext2
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// along with the Ccb value.
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// The Fcb is stored into the FsContext field.
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FileObject->FsContext = Fcb;
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FileObject->FsContext2 = Ccb;
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SetFlag( ((ULONG_PTR) FileObject->FsContext2), TypeOfOpen );
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// Set the Vpb field in the file object.
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FileObject->Vpb = Fcb->Vcb->Vpb;
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return;
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}
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TYPE_OF_OPEN
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UdfDecodeFileObject (
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IN PFILE_OBJECT FileObject,
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OUT PFCB *Fcb,
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OUT PCCB *Ccb
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)
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/*++
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Routine Description:
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This routine takes a file object and extracts the Fcb and Ccb (possibly NULL)
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and returns the type of open.
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Arguments:
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FileObject - Supplies the file object pointer being initialized.
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Fcb - Address to store the Fcb contained in the file object.
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Ccb - Address to store the Ccb contained in the file object.
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Return Value:
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TYPE_OF_OPEN - Indicates the type of file object.
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--*/
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{
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TYPE_OF_OPEN TypeOfOpen;
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PAGED_CODE();
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// If this is an unopened file object then return NULL for the
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// Fcb/Ccb. Don't trust any other values in the file object.
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TypeOfOpen = (TYPE_OF_OPEN) FlagOn( (ULONG_PTR) FileObject->FsContext2,
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TYPE_OF_OPEN_MASK );
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if (TypeOfOpen == UnopenedFileObject) {
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*Fcb = NULL;
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*Ccb = NULL;
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} else {
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// The Fcb is pointed to by the FsContext field. The Ccb is in
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// FsContext2 (after clearing the low three bits). The low three
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// bits are the file object type.
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*Fcb = FileObject->FsContext;
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*Ccb = FileObject->FsContext2;
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ClearFlag( (ULONG_PTR) *Ccb, TYPE_OF_OPEN_MASK );
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}
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// Now return the type of open.
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return TypeOfOpen;
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}
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TYPE_OF_OPEN
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UdfFastDecodeFileObject (
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IN PFILE_OBJECT FileObject,
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OUT PFCB *Fcb
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)
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/*++
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Routine Description:
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This procedure takes a pointer to a file object, that has already been
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opened by Udfs and does a quick decode operation. It will only return
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a non null value if the file object is a user file open
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Arguments:
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FileObject - Supplies the file object pointer being interrogated
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Fcb - Address to store Fcb if this is a user file object. NULL
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otherwise.
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Return Value:
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TYPE_OF_OPEN - type of open of this file object.
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--*/
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{
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PAGED_CODE();
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ASSERT_FILE_OBJECT( FileObject );
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// The Fcb is in the FsContext field. The type of open is in the low
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// bits of the Ccb.
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*Fcb = FileObject->FsContext;
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return (TYPE_OF_OPEN) FlagOn( (ULONG_PTR) FileObject->FsContext2, TYPE_OF_OPEN_MASK );
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}
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