dev2dos.c File Reference

#include <ntrtlp.h>
#include <mountdev.h>

Go to the source code of this file.

Classes
struct	_DEVICE_NAME_ENTRY
Typedefs
typedef _DEVICE_NAME_ENTRY	DEVICE_NAME_ENTRY
typedef _DEVICE_NAME_ENTRY *	PDEVICE_NAME_ENTRY
Functions
NTSTATUS	QuerySymbolicLink (IN PUNICODE_STRING SymbolicLinkName, OUT PUNICODE_STRING LinkTarget)
NTSTATUS	QueryDeviceNameForPath (IN PUNICODE_STRING Path, OUT PUNICODE_STRING DeviceName)
NTSTATUS	OpenDeviceReparseIndex (IN PUNICODE_STRING DeviceName, OUT PHANDLE Handle)
BOOLEAN	IsVolumeName (IN PUNICODE_STRING Name)
NTSTATUS	GetNextReparseVolumePath (IN HANDLE Handle, OUT PUNICODE_STRING Path)
NTSTATUS	FindPathForDevice (IN PUNICODE_STRING StartingPath, IN PUNICODE_STRING DeviceName, IN OUT PLIST_ENTRY DevicesInPath, OUT PUNICODE_STRING FinalPath)
NTSTATUS	RtlVolumeDeviceToDosName (IN PVOID VolumeDeviceObject, OUT PUNICODE_STRING DosName)

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Typedef Documentation

typedef struct _DEVICE_NAME_ENTRY DEVICE_NAME_ENTRY

typedef struct _DEVICE_NAME_ENTRY * PDEVICE_NAME_ENTRY

Referenced by FindPathForDevice().

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Function Documentation

NTSTATUS FindPathForDevice (  IN PUNICODE_STRING  StartingPath, IN PUNICODE_STRING  DeviceName, IN OUT PLIST_ENTRY  DevicesInPath, OUT PUNICODE_STRING  FinalPath )

Definition at line 454 of file dev2dos.c. References _DEVICE_NAME_ENTRY::DeviceName, ExAllocatePool, ExFreePool(), GetNextReparseVolumePath(), _DEVICE_NAME_ENTRY::ListEntry, NT_SUCCESS, NTSTATUS(), OpenDeviceReparseIndex(), PagedPool, path, PDEVICE_NAME_ENTRY, QueryDeviceNameForPath(), RtlEqualUnicodeString(), and TRUE. Referenced by RtlVolumeDeviceToDosName(). : This routine finds a path (if any) to the given device that begins with the given starting path. The final path returned includes the starting path. Arguments: StartingPath - Supplies the path to begin the search on. DeviceName - Supplies the device name whose path we are searching for. DevicesInPath - Supplies a list of the devices in all proper prefixes of the path. FinalPath - Returns the final path to the given device. Return Value: NTSTATUS --*/ { NTSTATUS status; UNICODE_STRING startingDeviceName; PLIST_ENTRY l; PDEVICE_NAME_ENTRY entry; HANDLE h; UNICODE_STRING path, newStart; status = QueryDeviceNameForPath(StartingPath, &startingDeviceName); if (!NT_SUCCESS(status)) { return status; } if (RtlEqualUnicodeString(DeviceName, &startingDeviceName, TRUE)) { ExFreePool(startingDeviceName.Buffer); FinalPath->Length = StartingPath->Length; FinalPath->MaximumLength = FinalPath->Length + sizeof(WCHAR); FinalPath->Buffer = ExAllocatePool(PagedPool, FinalPath->MaximumLength); if (!FinalPath->Buffer) { return STATUS_INSUFFICIENT_RESOURCES; } RtlCopyMemory(FinalPath->Buffer, StartingPath->Buffer, FinalPath->Length); FinalPath->Buffer[FinalPath->Length/sizeof(WCHAR)] = 0; return STATUS_SUCCESS; } for (l = DevicesInPath->Flink; l != DevicesInPath; l = l->Flink) { entry = CONTAINING_RECORD(l, DEVICE_NAME_ENTRY, ListEntry); if (RtlEqualUnicodeString(&entry->DeviceName, &startingDeviceName, TRUE)) { ExFreePool(startingDeviceName.Buffer); return STATUS_UNSUCCESSFUL; } } status = OpenDeviceReparseIndex(&startingDeviceName, &h); if (!NT_SUCCESS(status)) { ExFreePool(startingDeviceName.Buffer); return status; } entry = ExAllocatePool(PagedPool, sizeof(DEVICE_NAME_ENTRY)); if (!entry) { ZwClose(h); ExFreePool(startingDeviceName.Buffer); return STATUS_INSUFFICIENT_RESOURCES; } entry->DeviceName = startingDeviceName; InsertTailList(DevicesInPath, &entry->ListEntry); for (;;) { status = GetNextReparseVolumePath(h, &path); if (!NT_SUCCESS(status)) { break; } newStart.Length = StartingPath->Length + path.Length; newStart.MaximumLength = newStart.Length + sizeof(WCHAR); newStart.Buffer = ExAllocatePool(PagedPool, newStart.MaximumLength); if (!newStart.Buffer) { ExFreePool(path.Buffer); status = STATUS_INSUFFICIENT_RESOURCES; break; } RtlCopyMemory(newStart.Buffer, StartingPath->Buffer, StartingPath->Length); RtlCopyMemory((PCHAR) newStart.Buffer + StartingPath->Length, path.Buffer, path.Length); newStart.Buffer[newStart.Length/sizeof(WCHAR)] = 0; ExFreePool(path.Buffer); status = FindPathForDevice(&newStart, DeviceName, DevicesInPath, FinalPath); ExFreePool(newStart.Buffer); if (NT_SUCCESS(status)) { break; } } RemoveEntryList(&entry->ListEntry); ExFreePool(entry); ZwClose(h); ExFreePool(startingDeviceName.Buffer); return status; }

NTSTATUS GetNextReparseVolumePath (  IN HANDLE  Handle, OUT PUNICODE_STRING  Path )

Definition at line 326 of file dev2dos.c. References ExAllocatePool, ExFreePool(), FALSE, Handle, IsVolumeName(), NT_SUCCESS, NTSTATUS(), NULL, PagedPool, TRUE, USHORT, and ZwOpenFile(). Referenced by FindPathForDevice(). : This routine queries the reparse index for the next volume mount point. Arguments: Handle - Supplies the handle. Path - Returns the path. Return Value: NTSTATUS --*/ { NTSTATUS status; IO_STATUS_BLOCK ioStatus; FILE_REPARSE_POINT_INFORMATION reparseInfo; UNICODE_STRING fileId; OBJECT_ATTRIBUTES oa; HANDLE h; PREPARSE_DATA_BUFFER reparse; UNICODE_STRING volumeName; ULONG nameInfoSize; PFILE_NAME_INFORMATION nameInfo; for (;;) { status = ZwQueryDirectoryFile(Handle, NULL, NULL, NULL, &ioStatus, &reparseInfo, sizeof(reparseInfo), FileReparsePointInformation, TRUE, NULL, FALSE); if (!NT_SUCCESS(status)) { return status; } if (reparseInfo.Tag != IO_REPARSE_TAG_MOUNT_POINT) { continue; } fileId.Length = sizeof(reparseInfo.FileReference); fileId.MaximumLength = fileId.Length; fileId.Buffer = (PWSTR) &reparseInfo.FileReference; InitializeObjectAttributes(&oa, &fileId, 0, Handle, NULL); status = ZwOpenFile(&h, SYNCHRONIZE | FILE_GENERIC_READ, &oa, &ioStatus, FILE_SHARE_READ | FILE_SHARE_WRITE, FILE_OPEN_BY_FILE_ID | FILE_OPEN_REPARSE_POINT | FILE_SYNCHRONOUS_IO_ALERT); if (!NT_SUCCESS(status)) { continue; } reparse = ExAllocatePool(PagedPool, MAXIMUM_REPARSE_DATA_BUFFER_SIZE); if (!reparse) { ZwClose(h); return STATUS_INSUFFICIENT_RESOURCES; } status = ZwFsControlFile(h, NULL, NULL, NULL, &ioStatus, FSCTL_GET_REPARSE_POINT, NULL, 0, reparse, MAXIMUM_REPARSE_DATA_BUFFER_SIZE); if (!NT_SUCCESS(status)) { ExFreePool(reparse); ZwClose(h); continue; } volumeName.Length = reparse->MountPointReparseBuffer.SubstituteNameLength - sizeof(WCHAR); volumeName.MaximumLength = volumeName.Length + sizeof(WCHAR); volumeName.Buffer = (PWCHAR) ((PCHAR) reparse->MountPointReparseBuffer.PathBuffer + reparse->MountPointReparseBuffer.SubstituteNameOffset); volumeName.Buffer[volumeName.Length/sizeof(WCHAR)] = 0; if (!IsVolumeName(&volumeName)) { ExFreePool(reparse); ZwClose(h); continue; } ExFreePool(reparse); nameInfoSize = 1024; nameInfo = ExAllocatePool(PagedPool, nameInfoSize); if (!nameInfo) { ZwClose(h); continue; } status = ZwQueryInformationFile(h, &ioStatus, nameInfo, nameInfoSize, FileNameInformation); ZwClose(h); if (!NT_SUCCESS(status)) { continue; } Path->Length = (USHORT) nameInfo->FileNameLength; Path->MaximumLength = Path->Length + sizeof(WCHAR); Path->Buffer = ExAllocatePool(PagedPool, Path->MaximumLength); if (!Path->Buffer) { ExFreePool(nameInfo); continue; } RtlCopyMemory(Path->Buffer, nameInfo->FileName, Path->Length); Path->Buffer[Path->Length/sizeof(WCHAR)] = 0; ExFreePool(nameInfo); break; } return status; }

BOOLEAN IsVolumeName (  IN PUNICODE_STRING  Name  )

Definition at line 296 of file dev2dos.c. References FALSE, Name, and TRUE. Referenced by GetNextReparseVolumePath(). { if (Name->Length == 96 && Name->Buffer[0] == '\\' && Name->Buffer[1] == '?' && Name->Buffer[2] == '?' && Name->Buffer[3] == '\\' && Name->Buffer[4] == 'V' && Name->Buffer[5] == 'o' && Name->Buffer[6] == 'l' && Name->Buffer[7] == 'u' && Name->Buffer[8] == 'm' && Name->Buffer[9] == 'e' && Name->Buffer[10] == '{' && Name->Buffer[19] == '-' && Name->Buffer[24] == '-' && Name->Buffer[29] == '-' && Name->Buffer[34] == '-' && Name->Buffer[47] == '}') { return TRUE; } return FALSE; }

NTSTATUS OpenDeviceReparseIndex (  IN PUNICODE_STRING  DeviceName, OUT PHANDLE  Handle )

Definition at line 225 of file dev2dos.c. References _FILE_OBJECT::DeviceObject, ExAllocatePool, ExFreePool(), _VPB::Flags, Handle, IoGetDeviceObjectPointer(), L, NT_SUCCESS, NTSTATUS(), ObDereferenceObject, PagedPool, RtlInitUnicodeString(), _DEVICE_OBJECT::Vpb, VPB_MOUNTED, and ZwOpenFile(). Referenced by FindPathForDevice(). : This routine opens the reparse index on the given device. Arguments: DeviceName - Supplies the device name. Handle - Returns the handle. Return Value: NTSTATUS --*/ { NTSTATUS status; PFILE_OBJECT fileObject; PDEVICE_OBJECT deviceObject; UNICODE_STRING reparseSuffix, reparseName; OBJECT_ATTRIBUTES oa; IO_STATUS_BLOCK ioStatus; status = IoGetDeviceObjectPointer(DeviceName, FILE_READ_ATTRIBUTES, &fileObject, &deviceObject); if (!NT_SUCCESS(status)) { return status; } deviceObject = fileObject->DeviceObject; if (!deviceObject->Vpb || !(deviceObject->Vpb->Flags&VPB_MOUNTED)) { ObDereferenceObject(fileObject); return STATUS_UNSUCCESSFUL; } ObDereferenceObject(fileObject); RtlInitUnicodeString(&reparseSuffix, L"\\$Extend\\$Reparse:$R:$INDEX_ALLOCATION"); reparseName.Length = DeviceName->Length + reparseSuffix.Length; reparseName.MaximumLength = reparseName.Length + sizeof(WCHAR); reparseName.Buffer = ExAllocatePool(PagedPool, reparseName.MaximumLength); if (!reparseName.Buffer) { return STATUS_INSUFFICIENT_RESOURCES; } RtlCopyMemory(reparseName.Buffer, DeviceName->Buffer, DeviceName->Length); RtlCopyMemory((PCHAR) reparseName.Buffer + DeviceName->Length, reparseSuffix.Buffer, reparseSuffix.Length); reparseName.Buffer[reparseName.Length/sizeof(WCHAR)] = 0; InitializeObjectAttributes(&oa, &reparseName, OBJ_CASE_INSENSITIVE, 0, 0); status = ZwOpenFile(Handle, SYNCHRONIZE | FILE_LIST_DIRECTORY, &oa, &ioStatus, FILE_SHARE_READ | FILE_SHARE_WRITE, FILE_DIRECTORY_FILE | FILE_SYNCHRONOUS_IO_ALERT | FILE_OPEN_FOR_BACKUP_INTENT); ExFreePool(reparseName.Buffer); return status; }

NTSTATUS QueryDeviceNameForPath (  IN PUNICODE_STRING  Path, OUT PUNICODE_STRING  DeviceName )

Definition at line 149 of file dev2dos.c. References ExAllocatePool, ExFreePool(), NT_SUCCESS, NTSTATUS(), NULL, PagedPool, QuerySymbolicLink(), and ZwOpenFile(). Referenced by FindPathForDevice(). : This routine returns the device name for the given path. It first checks to see if the path is a symbolic link and then checks to see if it is a volume reparse point. Arguments: Path - Supplies the path. DeviceName - Returns the device name. Return Value: NTSTATUS --*/ { NTSTATUS status; OBJECT_ATTRIBUTES oa; HANDLE h; IO_STATUS_BLOCK ioStatus; PREPARSE_DATA_BUFFER reparse; UNICODE_STRING volumeName; status = QuerySymbolicLink(Path, DeviceName); if (NT_SUCCESS(status)) { return status; } InitializeObjectAttributes(&oa, Path, OBJ_CASE_INSENSITIVE, 0, 0); status = ZwOpenFile(&h, SYNCHRONIZE | FILE_GENERIC_READ, &oa, &ioStatus, FILE_SHARE_READ | FILE_SHARE_WRITE, FILE_OPEN_REPARSE_POINT | FILE_SYNCHRONOUS_IO_ALERT); if (!NT_SUCCESS(status)) { return status; } reparse = ExAllocatePool(PagedPool, MAXIMUM_REPARSE_DATA_BUFFER_SIZE); if (!reparse) { ZwClose(h); return STATUS_INSUFFICIENT_RESOURCES; } status = ZwFsControlFile(h, NULL, NULL, NULL, &ioStatus, FSCTL_GET_REPARSE_POINT, NULL, 0, reparse, MAXIMUM_REPARSE_DATA_BUFFER_SIZE); ZwClose(h); if (!NT_SUCCESS(status)) { ExFreePool(reparse); return status; } volumeName.Length = reparse->MountPointReparseBuffer.SubstituteNameLength - sizeof(WCHAR); volumeName.MaximumLength = volumeName.Length + sizeof(WCHAR); volumeName.Buffer = (PWCHAR) ((PCHAR) reparse->MountPointReparseBuffer.PathBuffer + reparse->MountPointReparseBuffer.SubstituteNameOffset); volumeName.Buffer[volumeName.Length/sizeof(WCHAR)] = 0; status = QuerySymbolicLink(&volumeName, DeviceName); ExFreePool(reparse); return status; }

NTSTATUS QuerySymbolicLink (  IN PUNICODE_STRING  SymbolicLinkName, OUT PUNICODE_STRING  LinkTarget )

Definition at line 94 of file dev2dos.c. References ExAllocatePool, ExFreePool(), NT_SUCCESS, NTSTATUS(), NULL, and PagedPool. Referenced by QueryDeviceNameForPath(), and RtlVolumeDeviceToDosName(). : This routine returns the target of the symbolic link name. Arguments: SymbolicLinkName - Supplies the symbolic link name. LinkTarget - Returns the link target. Return Value: NTSTATUS --*/ { OBJECT_ATTRIBUTES oa; NTSTATUS status; HANDLE h; InitializeObjectAttributes(&oa, SymbolicLinkName, OBJ_CASE_INSENSITIVE, 0, 0); status = ZwOpenSymbolicLinkObject(&h, GENERIC_READ, &oa); if (!NT_SUCCESS(status)) { return status; } LinkTarget->MaximumLength = 200*sizeof(WCHAR); LinkTarget->Length = 0; LinkTarget->Buffer = ExAllocatePool(PagedPool, LinkTarget->MaximumLength); if (!LinkTarget->Buffer) { ZwClose(h); return STATUS_INSUFFICIENT_RESOURCES; } status = ZwQuerySymbolicLinkObject(h, LinkTarget, NULL); ZwClose(h); if (!NT_SUCCESS(status)) { ExFreePool(LinkTarget->Buffer); } return status; }

NTSTATUS RtlVolumeDeviceToDosName (  IN PVOID  VolumeDeviceObject, OUT PUNICODE_STRING  DosName )

Definition at line 580 of file dev2dos.c. References c, CHAR, ExAllocatePool, Executive, ExFreePool(), FALSE, FindPathForDevice(), IoBuildDeviceIoControlRequest(), IoCallDriver, KeInitializeEvent, KernelMode, KeWaitForSingleObject(), L, NT_SUCCESS, NTSTATUS(), NULL, PagedPool, QuerySymbolicLink(), RtlEqualUnicodeString(), RtlInitUnicodeString(), and TRUE. 00587 : 00588 00589 This routine returns a valid DOS path for the given device object. 00590 This caller of this routine must call ExFreePool on DosName->Buffer 00591 when it is no longer needed. 00592 00593 Arguments: 00594 00595 VolumeDeviceObject - Supplies the volume device object. 00596 00597 DosName - Returns the DOS name for the volume 00598 00599 Return Value: 00600 00601 NTSTATUS 00602 00603 --*/ 00604 00605 { 00606 PDEVICE_OBJECT volumeDeviceObject = VolumeDeviceObject; 00607 PMOUNTDEV_NAME name; 00608 CHAR output[512]; 00609 KEVENT event; 00610 PIRP irp; 00611 IO_STATUS_BLOCK ioStatus; 00612 NTSTATUS status; 00613 UNICODE_STRING deviceName; 00614 WCHAR buffer[30]; 00615 UNICODE_STRING driveLetterName; 00616 WCHAR c; 00617 UNICODE_STRING linkTarget; 00618 LIST_ENTRY devicesInPath; 00619 00620 name = (PMOUNTDEV_NAME) output; 00621 KeInitializeEvent(&event, NotificationEvent, FALSE); 00622 irp = IoBuildDeviceIoControlRequest(IOCTL_MOUNTDEV_QUERY_DEVICE_NAME, 00623 volumeDeviceObject, NULL, 0, name, 512, 00624 FALSE, &event, &ioStatus); 00625 if (!irp) { 00626 return STATUS_INSUFFICIENT_RESOURCES; 00627 } 00628 00629 status = IoCallDriver(volumeDeviceObject, irp); 00630 if (status == STATUS_PENDING) { 00631 KeWaitForSingleObject(&event, Executive, KernelMode, FALSE, NULL); 00632 status = ioStatus.Status; 00633 } 00634 00635 if (!NT_SUCCESS(status)) { 00636 return status; 00637 } 00638 00639 deviceName.MaximumLength = deviceName.Length = name->NameLength; 00640 deviceName.Buffer = name->Name; 00641 00642 swprintf(buffer, L"\\??\\C:"); 00643 RtlInitUnicodeString(&driveLetterName, buffer); 00644 00645 for (c = 'A'; c <= 'Z'; c++) { 00646 driveLetterName.Buffer[4] = c; 00647 00648 status = QuerySymbolicLink(&driveLetterName, &linkTarget); 00649 if (!NT_SUCCESS(status)) { 00650 continue; 00651 } 00652 00653 if (RtlEqualUnicodeString(&linkTarget, &deviceName, TRUE)) { 00654 ExFreePool(linkTarget.Buffer); 00655 break; 00656 } 00657 00658 ExFreePool(linkTarget.Buffer); 00659 } 00660 00661 if (c <= 'Z') { 00662 DosName->Buffer = ExAllocatePool(PagedPool, 3*sizeof(WCHAR)); 00663 if (!DosName->Buffer) { 00664 return STATUS_INSUFFICIENT_RESOURCES; 00665 } 00666 DosName->MaximumLength = 6; 00667 DosName->Length = 4; 00668 DosName->Buffer[0] = c; 00669 DosName->Buffer[1] = ':'; 00670 DosName->Buffer[2] = 0; 00671 return STATUS_SUCCESS; 00672 } 00673 00674 for (c = 'A'; c <= 'Z'; c++) { 00675 driveLetterName.Buffer[4] = c; 00676 InitializeListHead(&devicesInPath); 00677 status = FindPathForDevice(&driveLetterName, &deviceName, 00678 &devicesInPath, DosName); 00679 00680 if (NT_SUCCESS(status)) { 00681 DosName->Length -= 4*sizeof(WCHAR); 00682 RtlMoveMemory(DosName->Buffer, &DosName->Buffer[4], 00683 DosName->Length); 00684 DosName->Buffer[DosName->Length/sizeof(WCHAR)] = 0; 00685 return status; 00686 } 00687 } 00688 00689 return status; 00690 } }

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