/*++ Copyright (c) 1992 Microsoft Corporation Module Name: udfs_rec.c Abstract: This module contains the mini-file system recognizer for UDFS. Author: Dan Lovinger (danlo) 13-Feb-1997 Environment: Kernel mode, local to I/O system Revision History: --*/ #include "fs_rec.h" #include "udfs_rec.h" // // The local debug trace level // #define Dbg (FSREC_DEBUG_LEVEL_UDFS) // // Tables of tokens we have to parse up from mount-time on-disk structures // PARSE_KEYVALUE VsdIdentParseTable[] = { { VSD_IDENT_BEA01, VsdIdentBEA01 }, { VSD_IDENT_TEA01, VsdIdentTEA01 }, { VSD_IDENT_CDROM, VsdIdentCDROM }, { VSD_IDENT_CD001, VsdIdentCD001 }, { VSD_IDENT_CDW01, VsdIdentCDW01 }, { VSD_IDENT_CDW02, VsdIdentCDW02 }, { VSD_IDENT_NSR01, VsdIdentNSR01 }, { VSD_IDENT_NSR02, VsdIdentNSR02 }, { VSD_IDENT_BOOT2, VsdIdentBOOT2 }, { VSD_IDENT_NSR03, VsdIdentNSR03 }, { NULL, VsdIdentBad } }; NTSTATUS UdfsRecGetLastSessionStart( IN PDEVICE_OBJECT DeviceObject, OUT PULONG Psn ); #ifdef ALLOC_PRAGMA #pragma alloc_text(PAGE,IsUdfsVolume) #pragma alloc_text(PAGE,UdfsFindInParseTable) #pragma alloc_text(PAGE,UdfsRecFsControl) #pragma alloc_text(PAGE,UdfsRecGetLastSessionStart) #endif // ALLOC_PRAGMA // // This macro copies an unaligned src longword to a dst longword, // performing an little/big endian swap. // #define SwapCopyUchar4(Dst,Src) { \ *((UNALIGNED UCHAR *)(Dst)) = *((UNALIGNED UCHAR *)(Src) + 3); \ *((UNALIGNED UCHAR *)(Dst) + 1) = *((UNALIGNED UCHAR *)(Src) + 2); \ *((UNALIGNED UCHAR *)(Dst) + 2) = *((UNALIGNED UCHAR *)(Src) + 1); \ *((UNALIGNED UCHAR *)(Dst) + 3) = *((UNALIGNED UCHAR *)(Src)); \ } #define Max(a,b) (((a) > (b)) ? (a) : (b)) NTSTATUS UdfsRecGetLastSessionStart( IN PDEVICE_OBJECT DeviceObject, OUT PULONG Psn ) /*++ Routine Description: This function queries the underlying device for the address of the first track in the last session. Does nothing for DISK devices. Arguments: DeviceObject - Pointer to this driver's device object. Psn - receives physical sector number of first block in last session, 0 for disk devices Return Value: The function value is the final status of the operation. -*/ { KEVENT Event; NTSTATUS Status; IO_STATUS_BLOCK ioStatus; CDROM_TOC_SESSION_DATA SessionData; PIRP Irp; *Psn = 0; if (DeviceObject->DeviceType != FILE_DEVICE_CD_ROM) { return STATUS_SUCCESS; } KeInitializeEvent( &Event, SynchronizationEvent, FALSE ); Irp = IoBuildDeviceIoControlRequest( IOCTL_CDROM_GET_LAST_SESSION, DeviceObject, (PVOID) NULL, 0, &SessionData, sizeof( SessionData ), FALSE, &Event, &ioStatus ); if (!Irp) { return STATUS_INSUFFICIENT_RESOURCES; } // // Override verify logic - we don't care. The fact we're in the picture means // someone is trying to mount new/changed media in the first place. // SetFlag( IoGetNextIrpStackLocation( Irp )->Flags, SL_OVERRIDE_VERIFY_VOLUME ); Status = IoCallDriver( DeviceObject, Irp ); if (Status == STATUS_PENDING) { (VOID) KeWaitForSingleObject( &Event, Executive, KernelMode, FALSE, (PLARGE_INTEGER) NULL ); Status = ioStatus.Status; } if (!NT_SUCCESS( Status )) { return Status; } if (SessionData.FirstCompleteSession != SessionData.LastCompleteSession) { SwapCopyUchar4( Psn, &SessionData.TrackData[0].Address ); } return STATUS_SUCCESS; } NTSTATUS UdfsRecFsControl( IN PDEVICE_OBJECT DeviceObject, IN PIRP Irp ) /*++ Routine Description: This function performs the mount and driver reload functions for this mini- file system recognizer driver. Arguments: DeviceObject - Pointer to this driver's device object. Irp - Pointer to the I/O Request Packet (IRP) representing the function to be performed. Return Value: The function value is the final status of the operation. -*/ { NTSTATUS status; PIO_STACK_LOCATION irpSp; PDEVICE_EXTENSION deviceExtension; UNICODE_STRING driverName; ULONG bytesPerSector; PDEVICE_OBJECT targetDevice; PAGED_CODE(); // // Begin by determining what function that is to be performed. // deviceExtension = (PDEVICE_EXTENSION) DeviceObject->DeviceExtension; irpSp = IoGetCurrentIrpStackLocation( Irp ); switch ( irpSp->MinorFunction ) { case IRP_MN_MOUNT_VOLUME: // // Attempt to mount a volume: There are two different cases here: // // 1) The device is being opened for DASD access, that is, no // file system is required, thus it is OK to allow RAW to // to open it. // // 2) We need to rummage the media to see if this is a UDF volume. // status = STATUS_UNRECOGNIZED_VOLUME; targetDevice = irpSp->Parameters.MountVolume.DeviceObject; if (FsRecGetDeviceSectorSize( targetDevice, &bytesPerSector )) { if (IsUdfsVolume( targetDevice, bytesPerSector )) { status = STATUS_FS_DRIVER_REQUIRED; } } break; case IRP_MN_LOAD_FILE_SYSTEM: status = FsRecLoadFileSystem( DeviceObject, L"\\Registry\\Machine\\System\\CurrentControlSet\\Services\\Udfs" ); break; default: status = STATUS_INVALID_DEVICE_REQUEST; } // // Finally, complete the request and return the same status code to the // caller. // Irp->IoStatus.Status = status; IoCompleteRequest( Irp, IO_NO_INCREMENT ); return status; } BOOLEAN IsUdfsVolume ( IN PDEVICE_OBJECT DeviceObject, IN ULONG SectorSize ) /*++ Routine Description: This routine walks the Volume Recognition Sequence to determine whether this volume contains an NSR02 (ISO 13346 Section 4) image. Note: this routine is pretty much diked out of UdfsRecognizeVolume in the real filesystem, modulo fitting it into the fs recognizer. Arguments: DeviceObject - device we are checking SectorSize - size of a physical sector on this device Return Value: Boolean TRUE if we found NSR02, FALSE otherwise. --*/ { BOOLEAN FoundNSR; BOOLEAN FoundBEA; BOOLEAN Resolved; ULONG LastSessionStartPsn; ULONG AssumedDescriptorSize = sizeof(VSD_GENERIC); PVSD_GENERIC VolumeStructureDescriptor = NULL; PVOID Buffer = NULL; ULONGLONG Offset; ULONGLONG StartOffset; PAGED_CODE(); DebugTrace(( +1, Dbg, "IsUdfsVolume, DevObj %08x SectorSize %08x\n", DeviceObject, SectorSize )); // // Find the start of the last session // if (!NT_SUCCESS( UdfsRecGetLastSessionStart( DeviceObject, &LastSessionStartPsn))) { return FALSE; } Retry: DebugTrace(( 0, Dbg, "IsUdfsVolume, Looking at session starting Psn == 0x%x\n", LastSessionStartPsn)); StartOffset = Offset = (SectorSize * LastSessionStartPsn) + SectorAlignN( SectorSize, VRA_BOUNDARY_LOCATION ); FoundNSR = FoundBEA = Resolved = FALSE; while (!Resolved) { // // The VRS descriptors are 2kb, and there's a lot of media out there where // people have interpreted this as meaning the descriptors should be aligned // on 2k boundries even on >2k sector size media. So we need to look at // both 2k and sector offsets on such media. (ECMA 2/8.4 specifies that these // descriptors shall all be aligned to the start of a sector). // if (0 == (Offset & (SectorSize - 1))) { if (!FsRecReadBlock( DeviceObject, (PLARGE_INTEGER)&Offset, sizeof(VSD_GENERIC), SectorSize, &Buffer, NULL )) { break; } VolumeStructureDescriptor = Buffer; } // // Now check the type of the descriptor. All ISO 13346 VSDs are // of Type 0, 9660 PVDs are Type 1, 9660 SVDs are Type 2, and 9660 // terminating descriptors are Type 255. // if (VolumeStructureDescriptor->Type == 0) { // // In order to properly recognize the volume, we must know all of the // Structure identifiers in ISO 13346 so that we can terminate if a // badly formatted (or, shockingly, non 13346) volume is presented to us. // switch (UdfsFindInParseTable( VsdIdentParseTable, VolumeStructureDescriptor->Ident, VSD_LENGTH_IDENT )) { case VsdIdentBEA01: // // Only one BEA may exist and its version must be 1 (2/9.2.3) // DebugTrace(( 0, Dbg, "IsUdfsVolume, got a BEA01\n" )); if ((FoundBEA && DebugTrace(( 0, Dbg, "IsUdfsVolume, ... but it is a duplicate!\n" ))) || (VolumeStructureDescriptor->Version != 1 && DebugTrace(( 0, Dbg, "IsUdfsVolume, ... but it has a wacky version number %02x != 1!\n", VolumeStructureDescriptor->Version )))) { Resolved = TRUE; break; } FoundBEA = TRUE; break; case VsdIdentTEA01: // // If we reach the TEA it must be the case that we don't recognize // DebugTrace(( 0, Dbg, "IsUdfsVolume, got a TEA01\n" )); Resolved = TRUE; break; case VsdIdentNSR02: case VsdIdentNSR03: // // We recognize NSR02 version 1 embedded after a BEA (3/9.1.3). For // simplicity we will not bother being a complete nitpick and check // for a bounding TEA, although we will be optimistic in the case where // we fail to match the version. // DebugTrace(( 0, Dbg, "IsUdfsVolume, got an NSR02/3\n" )); if ((FoundBEA || !DebugTrace(( 0, Dbg, "IsUdfsVolume, ... but we haven't seen a BEA01 yet!\n" ))) && (VolumeStructureDescriptor->Version == 1 || !DebugTrace(( 0, Dbg, "IsUdfsVolume, ... but it has a wacky version number %02x != 1\n", VolumeStructureDescriptor->Version )))) { FoundNSR = Resolved = TRUE; break; } break; case VsdIdentCD001: case VsdIdentCDW01: case VsdIdentNSR01: case VsdIdentCDW02: case VsdIdentBOOT2: DebugTrace(( 0, Dbg, "IsUdfsVolume, got a valid but uninteresting 13346 descriptor\n" )); // // Valid but uninteresting (to us) descriptors // break; default: DebugTrace(( 0, Dbg, "IsUdfsVolume, got an invalid 13346 descriptor\n" )); // // This probably was a false alert, but in any case there is nothing // on this volume for us. Exception is if this media sector size // is >= 4k, and this was the second descriptor. We'll allow // a failure here, and switch to reading in whole sector increments. // if ((Offset == (StartOffset + sizeof(VSD_GENERIC))) && (SectorSize > sizeof( VSD_GENERIC))) { Offset -= AssumedDescriptorSize; AssumedDescriptorSize = SectorSize; } else { Resolved = TRUE; } break; } } else if (!FoundBEA && (VolumeStructureDescriptor->Type < 3 || VolumeStructureDescriptor->Type == 255)) { DebugTrace(( 0, Dbg, "IsUdfsVolume, got a 9660 descriptor\n" )); // // Only HSG (CDROM) and 9660 (CD001) are possible, and they are only legal // before the ISO 13346 BEA/TEA extent. By design, an ISO 13346 VSD precisely // overlaps a 9660 PVD/SVD in the appropriate fields. // // Note that we aren't being strict about the structure of the 9660 descriptors // since that really isn't very interesting. We care more about the 13346. // // switch (UdfsFindInParseTable( VsdIdentParseTable, VolumeStructureDescriptor->Ident, VSD_LENGTH_IDENT )) { case VsdIdentCDROM: case VsdIdentCD001: DebugTrace(( 0, Dbg, "IsUdfsVolume, ... seems we have 9660 here\n" )); // // Note to our caller that we seem to have ISO 9660 here // break; default: DebugTrace(( 0, Dbg, "IsUdfsVolume, ... but it looks wacky\n" )); // // This probably was a false alert, but in any case there is nothing // on this volume for us. Exception is if this media sector size // is >= 4k, and this was the second descriptor. We'll allow // a failure here, and switch to reading in whole sector increments. // if ((Offset == (StartOffset + sizeof(VSD_GENERIC))) && (SectorSize > sizeof( VSD_GENERIC))) { Offset -= AssumedDescriptorSize; AssumedDescriptorSize = SectorSize; } else { Resolved = TRUE; } break; } } else { // // Something else must be recorded on this volume. // DebugTrace(( 0, Dbg, "IsUdfsVolume, got an unrecognizeable descriptor, probably not 13346/9660\n" )); break; } Offset += AssumedDescriptorSize; VolumeStructureDescriptor = (PVSD_GENERIC)(((PUCHAR)VolumeStructureDescriptor) + sizeof( VSD_GENERIC)); } // // If we were looking in the last session, and failed to find anything, then // go back and try the first. // if (!FoundNSR && (0 != LastSessionStartPsn)) { LastSessionStartPsn = 0; goto Retry; } DebugTrace(( -1, Dbg, "IsUdfsVolume -> %c\n", ( FoundNSR ? 'T' : 'F' ))); // // Free up our temporary buffer // if (Buffer) { ExFreePool( Buffer ); } return FoundNSR; } ULONG UdfsFindInParseTable ( IN PPARSE_KEYVALUE ParseTable, IN PCHAR Id, IN ULONG MaxIdLen ) /*++ Routine Description: This routine walks a table of string key/value information for a match of the input Id. MaxIdLen can be set to get a prefix match. Arguments: Table - This is the table being searched. Id - Key value. MaxIdLen - Maximum possible length of Id. Return Value: Value of matching entry, or the terminating (NULL) entry's value. --*/ { PAGED_CODE(); while (ParseTable->Key != NULL) { if (RtlEqualMemory(ParseTable->Key, Id, MaxIdLen)) { break; } ParseTable++; } return ParseTable->Value; }