winfsp/src/sys/fsext.c
2019-06-18 20:28:59 -07:00

118 lines
3.4 KiB
C

/**
* @file sys/fsext.c
*
* @copyright 2015-2019 Bill Zissimopoulos
*/
/*
* This file is part of WinFsp.
*
* You can redistribute it and/or modify it under the terms of the GNU
* General Public License version 3 as published by the Free Software
* Foundation.
*
* Licensees holding a valid commercial license may use this software
* in accordance with the commercial license agreement provided in
* conjunction with the software. The terms and conditions of any such
* commercial license agreement shall govern, supersede, and render
* ineffective any application of the GPLv3 license to this software,
* notwithstanding of any reference thereto in the software or
* associated repository.
*/
#include <sys/driver.h>
#include <winfsp/fsext.h>
static KSPIN_LOCK FsextSpinLock = 0;
FSP_FSEXT_PROVIDER *FsextProvider;
FSP_FSEXT_PROVIDER *FspFsextProvider(UINT32 ControlCode, PNTSTATUS PLoadResult)
{
FSP_FSEXT_PROVIDER *Provider;
KIRQL Irql;
KeAcquireSpinLock(&FsextSpinLock, &Irql);
Provider = FsextProvider;
KeReleaseSpinLock(&FsextSpinLock, Irql);
if (0 != PLoadResult)
{
if (0 == Provider)
{
WCHAR Buf[64 + 256];
UNICODE_STRING Path;
UNICODE_STRING Name;
union
{
KEY_VALUE_PARTIAL_INFORMATION V;
UINT8 B[FIELD_OFFSET(KEY_VALUE_PARTIAL_INFORMATION, Data) + 256];
} Value;
ULONG Length;
NTSTATUS Result;
RtlInitUnicodeString(&Path, L"" FSP_REGKEY "\\Fsext");
RtlInitEmptyUnicodeString(&Name, Buf, sizeof Buf);
Result = RtlUnicodeStringPrintf(&Name, L"%08x", ControlCode);
ASSERT(NT_SUCCESS(Result));
Length = sizeof Value;
Result = FspRegistryGetValue(&Path, &Name, &Value.V, &Length);
if (STATUS_SUCCESS != Result/*!NT_SUCCESS*/)
{
if (STATUS_BUFFER_OVERFLOW == Result)
Result = STATUS_BUFFER_TOO_SMALL;
*PLoadResult = Result;
return 0;
}
if (REG_SZ != Value.V.Type)
{
*PLoadResult = STATUS_OBJECT_NAME_NOT_FOUND;
return 0;
}
RtlInitEmptyUnicodeString(&Path, Buf, sizeof Buf);
Result = RtlUnicodeStringPrintf(&Path,
L"\\Registry\\Machine\\System\\CurrentControlSet\\Services\\%s", Value.V.Data);
ASSERT(NT_SUCCESS(Result));
Result = ZwLoadDriver(&Path);
if (!NT_SUCCESS(Result) && STATUS_IMAGE_ALREADY_LOADED != Result)
{
*PLoadResult = Result;
return 0;
}
KeAcquireSpinLock(&FsextSpinLock, &Irql);
Provider = FsextProvider;
KeReleaseSpinLock(&FsextSpinLock, Irql);
}
*PLoadResult = 0 != Provider ? STATUS_SUCCESS : STATUS_OBJECT_NAME_NOT_FOUND;
}
return Provider;
}
NTSTATUS FspFsextProviderRegister(FSP_FSEXT_PROVIDER *Provider)
{
NTSTATUS Result;
KIRQL Irql;
KeAcquireSpinLock(&FsextSpinLock, &Irql);
if (0 != FsextProvider)
{
Result = STATUS_TOO_LATE;
goto exit;
}
Provider->DeviceExtensionOffset = FIELD_OFFSET(FSP_FSVOL_DEVICE_EXTENSION, FsextData);
FsextProvider = Provider;
Result = STATUS_SUCCESS;
exit:
KeReleaseSpinLock(&FsextSpinLock, Irql);
return Result;
}