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sys: fsext: allow multiple providers (up to 4)

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Bill Zissimopoulos 2019-10-18 16:00:31 -07:00
parent 3c391ca711
commit 29fd9bf779
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GPG Key ID: 3D4F95D52C7B3EA3
1 changed files with 48 additions and 18 deletions
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66
src/sys/fsext.c
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@ -22,8 +22,41 @@
#include <sys/driver.h>
#include <winfsp/fsext.h>
/*
* Maximum number of allowed fsext providers. This must be kept small,
* because we do a linear search to find the provider. If this changes
* the data structure used to store providers (currently 2 parallel
* arrays) must be revisited.
*/
#define FSP_FSEXT_PROVIDER_COUNTMAX 4
static KSPIN_LOCK FsextSpinLock = 0;
FSP_FSEXT_PROVIDER *FsextProvider;
static UINT32 FsextControlCodes[FSP_FSEXT_PROVIDER_COUNTMAX];
static FSP_FSEXT_PROVIDER *FsextProviders[FSP_FSEXT_PROVIDER_COUNTMAX];
static inline
FSP_FSEXT_PROVIDER *FspFsextProviderGet(UINT32 FsextControlCode)
{
#if 0
for (ULONG I = 0; FSP_FSEXT_PROVIDER_COUNTMAX > I; I++)
if (FsextControlCode == FsextControlCodes[I])
return FsextProviders[I];
#else
/* unroll by hand */
FSP_FSCTL_STATIC_ASSERT(4 == FSP_FSEXT_PROVIDER_COUNTMAX,
"unrolled loop expects FsextProviders to have 4 elements");
if (FsextControlCode == FsextControlCodes[0])
return FsextProviders[0];
if (FsextControlCode == FsextControlCodes[1])
return FsextProviders[1];
if (FsextControlCode == FsextControlCodes[2])
return FsextProviders[2];
if (FsextControlCode == FsextControlCodes[3])
return FsextProviders[3];
#endif
return 0;
}
FSP_FSEXT_PROVIDER *FspFsextProvider(UINT32 FsextControlCode, PNTSTATUS PLoadResult)
{
@ -31,10 +64,9 @@ FSP_FSEXT_PROVIDER *FspFsextProvider(UINT32 FsextControlCode, PNTSTATUS PLoadRes
KIRQL Irql;
KeAcquireSpinLock(&FsextSpinLock, &Irql);
Provider = FsextProvider;
Provider = FspFsextProviderGet(FsextControlCode);
KeReleaseSpinLock(&FsextSpinLock, Irql);
if (0 != Provider && FsextControlCode != Provider->DeviceTransactCode)
Provider = 0;
ASSERT(0 == Provider || FsextControlCode == Provider->DeviceTransactCode);
if (0 != PLoadResult)
{
@ -81,10 +113,9 @@ FSP_FSEXT_PROVIDER *FspFsextProvider(UINT32 FsextControlCode, PNTSTATUS PLoadRes
}
KeAcquireSpinLock(&FsextSpinLock, &Irql);
Provider = FsextProvider;
Provider = FspFsextProviderGet(FsextControlCode);
KeReleaseSpinLock(&FsextSpinLock, Irql);
if (0 != Provider && FsextControlCode != Provider->DeviceTransactCode)
Provider = 0;
ASSERT(0 == Provider || FsextControlCode == Provider->DeviceTransactCode);
}
*PLoadResult = 0 != Provider ? STATUS_SUCCESS : STATUS_OBJECT_NAME_NOT_FOUND;
@ -100,18 +131,17 @@ NTSTATUS FspFsextProviderRegister(FSP_FSEXT_PROVIDER *Provider)
KeAcquireSpinLock(&FsextSpinLock, &Irql);
if (0 != FsextProvider)
{
Result = STATUS_TOO_LATE;
goto exit;
}
Result = STATUS_TOO_LATE;
for (ULONG I = 0; FSP_FSEXT_PROVIDER_COUNTMAX > I; I++)
if (0 == FsextControlCodes[I])
{
Provider->DeviceExtensionOffset = FIELD_OFFSET(FSP_FSVOL_DEVICE_EXTENSION, FsextData);
FsextControlCodes[I] = Provider->DeviceTransactCode;
FsextProviders[I] = Provider;
Result = STATUS_SUCCESS;
break;
}
Provider->DeviceExtensionOffset = FIELD_OFFSET(FSP_FSVOL_DEVICE_EXTENSION, FsextData);
FsextProvider = Provider;
Result = STATUS_SUCCESS;
exit:
KeReleaseSpinLock(&FsextSpinLock, Irql);
return Result;