sys: FspIopDispatchPrepare

src/sys/create.c

@@ -13,6 +13,7 @@ static NTSTATUS FspFsvrtCreate(
 static NTSTATUS FspFsvolCreate(
     PDEVICE_OBJECT DeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp);
 FSP_DRIVER_DISPATCH FspCreate;
+FSP_IOPREP_DISPATCH FspCreatePrepare;
 FSP_IOCMPL_DISPATCH FspCreateComplete;
 
 #ifdef ALLOC_PRAGMA
@@ -20,6 +21,7 @@ FSP_IOCMPL_DISPATCH FspCreateComplete;
 #pragma alloc_text(PAGE, FspFsvrtCreate)
 #pragma alloc_text(PAGE, FspFsvolCreate)
 #pragma alloc_text(PAGE, FspCreate)
+#pragma alloc_text(PAGE, FspCreatePrepare)
 #pragma alloc_text(PAGE, FspCreateComplete)
 #endif
 
@@ -347,6 +349,14 @@ NTSTATUS FspCreate(
         Irp->AssociatedIrp.SystemBuffer, IrpSp->Parameters.Create.EaLength);
 }
 
+NTSTATUS FspCreatePrepare(
+    PIRP Irp, FSP_FSCTL_TRANSACT_REQ *Request)
+{
+    PAGED_CODE();
+
+    return STATUS_SUCCESS;
+}
+
 VOID FspCreateComplete(
     PIRP Irp, const FSP_FSCTL_TRANSACT_RSP *Response)
 {

src/sys/driver.c

@@ -62,6 +62,9 @@ NTSTATUS DriverEntry(
     DriverObject->MajorFunction[IRP_MJ_QUERY_SECURITY] = FspQuerySecurity;
     DriverObject->MajorFunction[IRP_MJ_SET_SECURITY] = FspSetSecurity;
 
+    /* setup the I/O preparation functions */
+    FspIopPrepareFunction[IRP_MJ_CREATE] = FspCreatePrepare;
+
     /* setup the I/O completion functions */
     FspIopCompleteFunction[IRP_MJ_CREATE] = FspCreateComplete;
     FspIopCompleteFunction[IRP_MJ_CLOSE] = FspCloseComplete;

src/sys/driver.h

@@ -197,8 +197,13 @@ _Dispatch_type_(IRP_MJ_WRITE)           FSP_DRIVER_DISPATCH FspWrite;
 /* I/O processing functions */
 _IRQL_requires_max_(APC_LEVEL)
 _IRQL_requires_same_
+typedef NTSTATUS FSP_IOPREP_DISPATCH(
+    _Inout_ PIRP Irp, _Inout_ FSP_FSCTL_TRANSACT_REQ *Request);
+_IRQL_requires_max_(APC_LEVEL)
+_IRQL_requires_same_
 typedef VOID FSP_IOCMPL_DISPATCH(
     _Inout_ PIRP Irp, _In_ const FSP_FSCTL_TRANSACT_RSP *Response);
+FSP_IOPREP_DISPATCH FspCreatePrepare;
 FSP_IOCMPL_DISPATCH FspCleanupComplete;
 FSP_IOCMPL_DISPATCH FspCloseComplete;
 FSP_IOCMPL_DISPATCH FspCreateComplete;
@@ -255,6 +260,7 @@ static inline VOID FspIopCompleteRequest(PIRP Irp, NTSTATUS Result)
 {
     FspIopCompleteRequestEx(Irp, Result, TRUE);
 }
+NTSTATUS FspIopDispatchPrepare(PIRP Irp, FSP_FSCTL_TRANSACT_REQ *Request);
 VOID FspIopDispatchComplete(PIRP Irp, const FSP_FSCTL_TRANSACT_RSP *Response);
 
 /* device management */
@@ -371,6 +377,7 @@ const char *IoctlCodeSym(ULONG ControlCode);
 extern PDRIVER_OBJECT FspDriverObject;
 extern PDEVICE_OBJECT FspFsctlDiskDeviceObject;
 extern PDEVICE_OBJECT FspFsctlNetDeviceObject;
+extern FSP_IOPREP_DISPATCH *FspIopPrepareFunction[];
 extern FSP_IOCMPL_DISPATCH *FspIopCompleteFunction[];
 
 #endif

src/sys/fsctl.c

@@ -378,6 +378,7 @@ static NTSTATUS FspFsvrtTransact(
     }
 
     /* wait for an IRP to arrive */
+retry:
     while (0 == (PendingIrp = FspIoqNextPendingIrp(&FsvrtDeviceExtension->Ioq, (ULONG)-1L)))
     {
         if (FspIoqStopped(&FsvrtDeviceExtension->Ioq))
@@ -392,6 +393,11 @@ static NTSTATUS FspFsvrtTransact(
     {
         PendingIrpRequest = PendingIrp->Tail.Overlay.DriverContext[0];
 
+        Result = FspIopDispatchPrepare(PendingIrp, PendingIrpRequest);
+        if (!NT_SUCCESS(Result))
+            FspIopCompleteRequest(PendingIrp, Result);
+        else
+        {
             NextRequest = FspFsctlTransactProduceRequest(
                 Request, PendingIrpRequest->Size, SystemBufferEnd);
                 /* this should not fail as we have already checked that we have enough space */
@@ -416,12 +422,17 @@ static NTSTATUS FspFsvrtTransact(
             /* check that we have enough space before pulling the next pending IRP off the queue */
             if ((PUINT8)Request + FSP_FSCTL_TRANSACT_REQ_SIZEMAX > SystemBufferEnd)
                 break;
+        }
 
         PendingIrp = FspIoqNextPendingIrp(&FsvrtDeviceExtension->Ioq, 0);
         if (0 == PendingIrp)
             break;
 
     }
+
+    if (Request == SystemBuffer)
+        goto retry;
+
     RtlZeroMemory(Request, SystemBufferEnd - (PUINT8)Request);
     Irp->IoStatus.Information = (PUINT8)Request - (PUINT8)SystemBuffer;
 

src/sys/iop.c

@@ -8,10 +8,12 @@
 
 NTSTATUS FspIopCreateRequest(
     PIRP Irp, PUNICODE_STRING FileName, ULONG ExtraSize, FSP_FSCTL_TRANSACT_REQ **PRequest);
+NTSTATUS FspIopDispatchPrepare(PIRP Irp, FSP_FSCTL_TRANSACT_REQ *Request);
 VOID FspIopDispatchComplete(PIRP Irp, const FSP_FSCTL_TRANSACT_RSP *Response);
 
 #ifdef ALLOC_PRAGMA
 #pragma alloc_text(PAGE, FspIopCreateRequest)
+#pragma alloc_text(PAGE, FspIopDispatchPrepare)
 #pragma alloc_text(PAGE, FspIopDispatchComplete)
 #endif
 
@@ -74,6 +76,19 @@ VOID FspIopCompleteRequestEx(PIRP Irp, NTSTATUS Result, BOOLEAN DeviceRelease)
         FspDeviceRelease(DeviceObject);
 }
 
+NTSTATUS FspIopDispatchPrepare(PIRP Irp, FSP_FSCTL_TRANSACT_REQ *Request)
+{
+    PAGED_CODE();
+
+    PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);
+
+    ASSERT(IRP_MJ_MAXIMUM_FUNCTION >= IrpSp->MajorFunction);
+    if (0 != FspIopPrepareFunction[IrpSp->MajorFunction])
+        return FspIopPrepareFunction[IrpSp->MajorFunction](Irp, Request);
+    else
+        return STATUS_SUCCESS;
+}
+
 VOID FspIopDispatchComplete(PIRP Irp, const FSP_FSCTL_TRANSACT_RSP *Response)
 {
     PAGED_CODE();
@@ -86,4 +101,5 @@ VOID FspIopDispatchComplete(PIRP Irp, const FSP_FSCTL_TRANSACT_RSP *Response)
     FspIopCompleteFunction[IrpSp->MajorFunction](Irp, Response);
 }
 
+FSP_IOPREP_DISPATCH *FspIopPrepareFunction[IRP_MJ_MAXIMUM_FUNCTION + 1];
 FSP_IOCMPL_DISPATCH *FspIopCompleteFunction[IRP_MJ_MAXIMUM_FUNCTION + 1];