- Fix KeAttackProcess, KeStackAttachProcess, KeUnstackDetachProcess and KeDetachProce...
[reactos.git] / reactos / ntoskrnl / ke / process.c
index 15486ec..70ced19 100644 (file)
-/* $Id$
- *
+/*
  * COPYRIGHT:       See COPYING in the top level directory
- * PROJECT:         ReactOS kernel
+ * PROJECT:         ReactOS Kernel
  * FILE:            ntoskrnl/ke/process.c
- * PURPOSE:         Microkernel process management
- * 
- * PROGRAMMERS:     David Welch (welch@cwcom.net)
+ * PURPOSE:         Kernel Process Management and System Call Tables
+ * PROGRAMMERS:     Alex Ionescu
+ *                  Gregor Anich
  */
 
 /* INCLUDES *****************************************************************/
 
 #include <ntoskrnl.h>
+#include <internal/napi.h>
 #define NDEBUG
 #include <internal/debug.h>
 
+/* GLOBALS   *****************************************************************/
+
+KSERVICE_TABLE_DESCRIPTOR
+__declspec(dllexport)
+KeServiceDescriptorTable[SSDT_MAX_ENTRIES] =
+{
+    { MainSSDT, NULL, NUMBER_OF_SYSCALLS, MainSSPT },
+    { NULL,     NULL,   0,   NULL   },
+    { NULL,     NULL,   0,   NULL   },
+    { NULL,     NULL,   0,   NULL   }
+};
+
+KSERVICE_TABLE_DESCRIPTOR
+KeServiceDescriptorTableShadow[SSDT_MAX_ENTRIES] =
+{
+    { MainSSDT, NULL, NUMBER_OF_SYSCALLS, MainSSPT },
+    { NULL,     NULL,   0,   NULL   },
+    { NULL,     NULL,   0,   NULL   },
+    { NULL,     NULL,   0,   NULL   }
+};
+
 /* FUNCTIONS *****************************************************************/
 
-static inline void
-UpdatePageDirs(PKTHREAD Thread, PKPROCESS Process)
+PKPROCESS
+STDCALL
+KeGetCurrentProcess(VOID)
 {
-   /* The stack and the thread structure of the current process may be 
-      located in a page which is not present in the page directory of 
-      the process we're attaching to. That would lead to a page fault 
-      when this function returns. However, since the processor can't 
-      call the page fault handler 'cause it can't push EIP on the stack, 
-      this will show up as a stack fault which will crash the entire system.
-      To prevent this, make sure the page directory of the process we're
-      attaching to is up-to-date. */
-   MmUpdatePageDir((PEPROCESS)Process, (PVOID)Thread->StackLimit, MM_STACK_SIZE);
-   MmUpdatePageDir((PEPROCESS)Process, (PVOID)Thread, sizeof(ETHREAD));
+    return(&(PsGetCurrentProcess()->Pcb));
 }
 
-/*
- * @implemented
- */
-VOID 
-STDCALL
-KeAttachProcess(PKPROCESS Process)
+static __inline
+VOID
+NTAPI
+UpdatePageDirs(IN PKTHREAD Thread,
+               IN PKPROCESS Process)
 {
-       KIRQL OldIrql;
-       PKTHREAD Thread = KeGetCurrentThread();
-       
-       DPRINT("KeAttachProcess: %x\n", Process);
-
-       UpdatePageDirs(Thread, Process);
-
-       /* Lock Dispatcher */
-       OldIrql = KeAcquireDispatcherDatabaseLock();
-       
-       /* Crash system if DPC is being executed! */
-       if (KeIsExecutingDpc()) {
-               DPRINT1("Invalid attach (Thread is executing a DPC!)\n");
-               KEBUGCHECK(INVALID_PROCESS_ATTACH_ATTEMPT);
-       }
-       
-       /* Check if the Target Process is already attached */
-       if (Thread->ApcState.Process == Process || Thread->ApcStateIndex != OriginalApcEnvironment) {
-               DPRINT("Process already Attached. Exitting\n");
-               KeReleaseDispatcherDatabaseLock(OldIrql);
-       } else { 
-               KiAttachProcess(Thread, Process, OldIrql, &Thread->SavedApcState);
-       }
+    /*
+     * The stack and the thread structure of the current process may be
+     * located in a page which is not present in the page directory of
+     * the process we're attaching to. That would lead to a page fault
+     * when this function returns. However, since the processor can't
+     * call the page fault handler 'cause it can't push EIP on the stack,
+     * this will show up as a stack fault which will crash the entire system.
+     * To prevent this, make sure the page directory of the process we're
+     * attaching to is up-to-date.
+     */
+    MmUpdatePageDir((PEPROCESS)Process, (PVOID)Thread->StackLimit, MM_STACK_SIZE);
+    MmUpdatePageDir((PEPROCESS)Process, (PVOID)Thread, sizeof(ETHREAD));
 }
 
 VOID
-STDCALL
-KiAttachProcess(PKTHREAD Thread, PKPROCESS Process, KIRQL ApcLock, PRKAPC_STATE SavedApcState)
+NTAPI
+KiAttachProcess(PKTHREAD Thread,
+                PKPROCESS Process,
+                KIRQL OldIrql,
+                PRKAPC_STATE SavedApcState)
 {
-  
-       DPRINT("KiAttachProcess(Thread: %x, Process: %x, SavedApcState: %x\n", Thread, Process, SavedApcState);
-   
-       /* Increase Stack Count */
-       Process->StackCount++;
-       
-       /* Swap the APC Environment */
-       KiMoveApcState(&Thread->ApcState, SavedApcState);
-       
-       /* Reinitialize Apc State */
-       InitializeListHead(&Thread->ApcState.ApcListHead[KernelMode]);
-       InitializeListHead(&Thread->ApcState.ApcListHead[UserMode]);
-       Thread->ApcState.Process = Process;
-       Thread->ApcState.KernelApcInProgress = FALSE;
-       Thread->ApcState.KernelApcPending = FALSE;
-       Thread->ApcState.UserApcPending = FALSE;
-    
-       /* Update Environment Pointers if needed*/
-       if (SavedApcState == &Thread->SavedApcState) {
-               Thread->ApcStatePointer[OriginalApcEnvironment] = &Thread->SavedApcState;
-               Thread->ApcStatePointer[AttachedApcEnvironment] = &Thread->ApcState;
-               Thread->ApcStateIndex = AttachedApcEnvironment;
-       }
-       
-       /* Swap the Processes */
-       KiSwapProcess(Process, SavedApcState->Process);
-       
-       /* Return to old IRQL*/
-       KeReleaseDispatcherDatabaseLock(ApcLock);
-       
-       DPRINT("KiAttachProcess Completed Sucesfully\n");
+    ASSERT(Process != Thread->ApcState.Process);
+    DPRINT("KiAttachProcess(Thread: %x, Process: %x, SavedApcState: %x\n",
+            Thread, Process, SavedApcState);
+
+    /* Increase Stack Count */
+    Process->StackCount++;
+
+    /* Swap the APC Environment */
+    KiMoveApcState(&Thread->ApcState, SavedApcState);
+
+    /* Reinitialize Apc State */
+    InitializeListHead(&Thread->ApcState.ApcListHead[KernelMode]);
+    InitializeListHead(&Thread->ApcState.ApcListHead[UserMode]);
+    Thread->ApcState.Process = Process;
+    Thread->ApcState.KernelApcInProgress = FALSE;
+    Thread->ApcState.KernelApcPending = FALSE;
+    Thread->ApcState.UserApcPending = FALSE;
+
+    /* Update Environment Pointers if needed*/
+    if (SavedApcState == &Thread->SavedApcState)
+    {
+        Thread->ApcStatePointer[OriginalApcEnvironment] = &Thread->SavedApcState;
+        Thread->ApcStatePointer[AttachedApcEnvironment] = &Thread->ApcState;
+        Thread->ApcStateIndex = AttachedApcEnvironment;
+    }
+
+    /* Check if the process is paged in */
+    if (Process->State == ProcessInMemory)
+    {
+        /* FIXME: Scan the Ready Thread List once new scheduler is in */
+
+        /* Swap the Processes */
+        KiSwapProcess(Process, SavedApcState->Process);
+
+        /* Return to old IRQL*/
+        KeReleaseDispatcherDatabaseLock(OldIrql);
+    }
+    else
+    {
+        DPRINT1("Errr. ReactOS doesn't support paging out processes yet...\n");
+        DbgBreakPoint();
+    }
 }
 
 VOID
-STDCALL
-KiSwapProcess(PKPROCESS NewProcess, PKPROCESS OldProcess) 
+NTAPI
+KeInitializeProcess(PKPROCESS Process,
+                    KPRIORITY Priority,
+                    KAFFINITY Affinity,
+                    LARGE_INTEGER DirectoryTableBase)
+{
+    DPRINT("KeInitializeProcess. Process: %x, DirectoryTableBase: %x\n",
+            Process, DirectoryTableBase);
+
+    /* Initialize the Dispatcher Header */
+    KeInitializeDispatcherHeader(&Process->Header,
+                                 ProcessObject,
+                                 sizeof(KPROCESS),
+                                 FALSE);
+
+    /* Initialize Scheduler Data, Disable Alignment Faults and Set the PDE */
+    Process->Affinity = Affinity;
+    Process->BasePriority = Priority;
+    Process->QuantumReset = 6;
+    Process->DirectoryTableBase = DirectoryTableBase;
+    Process->AutoAlignment = TRUE;
+    Process->IopmOffset = 0xFFFF;
+    Process->State = ProcessInMemory;
+
+    /* Initialize the Thread List */
+    InitializeListHead(&Process->ThreadListHead);
+    KeInitializeSpinLock(&Process->ProcessLock);
+    DPRINT("The Process has now been initalized with the Kernel\n");
+}
+
+ULONG
+NTAPI
+KeSetProcess(PKPROCESS Process,
+             KPRIORITY Increment)
+{
+    KIRQL OldIrql;
+    ULONG OldState;
+
+    /* Lock Dispatcher */
+    OldIrql = KeAcquireDispatcherDatabaseLock();
+
+    /* Get Old State */
+    OldState = Process->Header.SignalState;
+
+    /* Signal the Process */
+    Process->Header.SignalState = TRUE;
+    if ((OldState == 0) && IsListEmpty(&Process->Header.WaitListHead) != TRUE)
+    {
+        /* Satisfy waits */
+        KiWaitTest((PVOID)Process, Increment);
+    }
+
+    /* Release Dispatcher Database */
+    KeReleaseDispatcherDatabaseLock(OldIrql);
+
+    /* Return the previous State */
+    return OldState;
+}
+
+VOID
+NTAPI
+KiSwapProcess(PKPROCESS NewProcess,
+              PKPROCESS OldProcess)
 {
-       //PKPCR Pcr = KeGetCurrentKpcr();
-
-       /* Do they have an LDT? */
-       if ((NewProcess->LdtDescriptor) || (OldProcess->LdtDescriptor)) {
-               /* FIXME : SWitch GDT/IDT */
-       }
-       DPRINT("Switching CR3 to: %x\n", NewProcess->DirectoryTableBase.u.LowPart);
-       Ke386SetPageTableDirectory(NewProcess->DirectoryTableBase.u.LowPart);
-       
-       /* FIXME: Set IopmOffset in TSS */
+    DPRINT("Switching CR3 to: %x\n", NewProcess->DirectoryTableBase.u.LowPart);
+    Ke386SetPageTableDirectory(NewProcess->DirectoryTableBase.u.LowPart);
 }
 
 /*
  * @implemented
  */
-BOOLEAN
-STDCALL
-KeIsAttachedProcess(
-       VOID
-       )
+VOID
+NTAPI
+KeAttachProcess(PKPROCESS Process)
 {
-       return KeGetCurrentThread()->ApcStateIndex;
+    KIRQL OldIrql;
+    PKTHREAD Thread;
+    ASSERT_IRQL_LESS_OR_EQUAL(DISPATCH_LEVEL);
+    DPRINT("KeAttachProcess: %x\n", Process);
+
+    /* Make sure that we are in the right page directory */
+    Thread = KeGetCurrentThread();
+    UpdatePageDirs(Thread, Process);
+
+    /* Lock Dispatcher */
+    OldIrql = KeAcquireDispatcherDatabaseLock();
+
+    /* Check if we're already in that process */
+    if (Thread->ApcState.Process == Process)
+    {
+        /* Unlock the dispatcher, nothing to do */
+        KeReleaseDispatcherDatabaseLock(OldIrql);
+    }
+    else if ((Thread->ApcStateIndex != OriginalApcEnvironment) ||
+             (KeIsExecutingDpc()))
+    {
+        /* Executing a DPC or already attached, crash! */
+        KEBUGCHECKEX(INVALID_PROCESS_ATTACH_ATTEMPT,
+                     (ULONG_PTR)Process,
+                     (ULONG_PTR)Thread->ApcState.Process,
+                     Thread->ApcStateIndex,
+                     KeIsExecutingDpc());
+    }
+    else
+    {
+        /* Legit attach attempt: do it! */
+        KiAttachProcess(Thread, Process, OldIrql, &Thread->SavedApcState);
+    }
 }
 
 /*
  * @implemented
  */
 VOID
-STDCALL
-KeStackAttachProcess (
-    IN PKPROCESS Process,
-    OUT PRKAPC_STATE ApcState
-    )
+NTAPI
+KeDetachProcess (VOID)
 {
-       KIRQL OldIrql;
-       PKTHREAD Thread = KeGetCurrentThread();
-
-       UpdatePageDirs(Thread, Process);
-
-       OldIrql = KeAcquireDispatcherDatabaseLock();
-       
-       /* Crash system if DPC is being executed! */
-       if (KeIsExecutingDpc()) {
-               DPRINT1("Invalid attach (Thread is executing a DPC!)\n");
-               KEBUGCHECK(INVALID_PROCESS_ATTACH_ATTEMPT);
-       }
-       
-       /* Check if the Target Process is already attached */
-       if (Thread->ApcState.Process == Process) {
-               ApcState->Process = (PKPROCESS)1;  /* Meaning already attached to the same Process */
-       } else { 
-               /* Check if the Current Thread is already attached and call the Internal Function*/
-               if (Thread->ApcStateIndex != OriginalApcEnvironment) {
-                       KiAttachProcess(Thread, Process, OldIrql, ApcState);
-               } else {
-                       KiAttachProcess(Thread, Process, OldIrql, &Thread->SavedApcState);
-                       ApcState->Process = NULL; 
-               }
-       }
+    PKTHREAD Thread;
+    KIRQL OldIrql;
+    ASSERT_IRQL_LESS_OR_EQUAL(DISPATCH_LEVEL);
+    DPRINT("KeDetachProcess()\n");
+
+    /* Get Current Thread and lock the dispatcher */
+    Thread = KeGetCurrentThread();
+    OldIrql = KeAcquireDispatcherDatabaseLock();
+
+    /* Check if it's attached */
+    if (Thread->ApcStateIndex != OriginalApcEnvironment)
+    {
+        /* It is, decrease Stack Count */
+        if(!(--Thread->ApcState.Process->StackCount))
+        {
+            /* FIXME: Swap the process out */
+        }
+
+        /* Restore the APC State */
+        KiMoveApcState(&Thread->SavedApcState, &Thread->ApcState);
+        Thread->SavedApcState.Process = NULL;
+        Thread->ApcStatePointer[OriginalApcEnvironment] = &Thread->ApcState;
+        Thread->ApcStatePointer[AttachedApcEnvironment] = &Thread->SavedApcState;
+        Thread->ApcStateIndex = OriginalApcEnvironment;
+
+        /* Check if we have pending APCs */
+        if (IsListEmpty(&Thread->ApcState.ApcListHead[KernelMode]))
+        {
+            /* What do you know, we do! Request them to be delivered */
+            Thread->ApcState.KernelApcPending = TRUE;
+            HalRequestSoftwareInterrupt(APC_LEVEL);
+        }
+
+        /* Swap Processes */
+        KiSwapProcess(Thread->ApcState.Process, Thread->ApcState.Process);
+    }
+
+    /* Unlock Dispatcher */
+    KeReleaseDispatcherDatabaseLock(OldIrql);
 }
 
 /*
  * @implemented
  */
-VOID STDCALL
-KeDetachProcess (VOID)
+BOOLEAN
+NTAPI
+KeIsAttachedProcess(VOID)
 {
-       PKTHREAD Thread;
-       KIRQL OldIrql;
-   
-       DPRINT("KeDetachProcess()\n");
-   
-       /* Get Current Thread and Lock */
-       Thread = KeGetCurrentThread();
-       OldIrql = KeAcquireDispatcherDatabaseLock();
-       
-       /* Check if it's attached */
-       DPRINT("Current ApcStateIndex: %x\n", Thread->ApcStateIndex);
-       
-       if (Thread->ApcStateIndex == OriginalApcEnvironment) {
-               DPRINT1("Invalid detach (thread was not attached)\n");
-               KEBUGCHECK(INVALID_PROCESS_DETACH_ATTEMPT);
-       }
-   
-       /* Decrease Stack Count */
-       Thread->ApcState.Process->StackCount--;
-       
-       /* Restore the APC State */
-       KiMoveApcState(&Thread->SavedApcState, &Thread->ApcState);
-       Thread->SavedApcState.Process = NULL;
-       Thread->ApcStatePointer[OriginalApcEnvironment] = &Thread->ApcState;
-       Thread->ApcStatePointer[AttachedApcEnvironment] = &Thread->SavedApcState;
-       Thread->ApcStateIndex = OriginalApcEnvironment;
-       
-       /* Swap Processes */
-       KiSwapProcess(Thread->ApcState.Process, Thread->ApcState.Process);
-
-       /* Unlock Dispatcher */
-       KeReleaseDispatcherDatabaseLock(OldIrql);
+    /* Return the APC State */
+    return KeGetCurrentThread()->ApcStateIndex;
 }
 
 /*
  * @implemented
  */
 VOID
-STDCALL
-KeUnstackDetachProcess (
-    IN PRKAPC_STATE ApcState
-    )
+NTAPI
+KeStackAttachProcess(IN PKPROCESS Process,
+                     OUT PRKAPC_STATE ApcState)
 {
-       KIRQL OldIrql;
-       PKTHREAD Thread;
-
-       /* If the special "We tried to attach to the process already being attached to" flag is there, don't do anything */
-       if (ApcState->Process == (PKPROCESS)1) return;
-       
-       Thread = KeGetCurrentThread();
-       OldIrql = KeAcquireDispatcherDatabaseLock();
-       
-       /* Sorry Buddy, can't help you if you've got APCs or just aren't attached */
-       if ((Thread->ApcStateIndex == OriginalApcEnvironment) || (Thread->ApcState.KernelApcInProgress)) {
-               DPRINT1("Invalid detach (Thread not Attached, or Kernel APC in Progress!)\n");
-               KEBUGCHECK(INVALID_PROCESS_DETACH_ATTEMPT);
-       }
-       
-       /* Restore the Old APC State if a Process was present */
-       if (ApcState->Process) {
-               KiMoveApcState(ApcState, &Thread->ApcState);
-       } else {
-               /* The ApcState parameter is useless, so use the saved data and reset it */
-               KiMoveApcState(&Thread->SavedApcState, &Thread->ApcState);
-               Thread->SavedApcState.Process = NULL;
-               Thread->ApcStateIndex = OriginalApcEnvironment;
-               Thread->ApcStatePointer[OriginalApcEnvironment] = &Thread->ApcState;
-               Thread->ApcStatePointer[AttachedApcEnvironment] = &Thread->SavedApcState;
-       }
-
-       /* Swap Processes */
-       KiSwapProcess(Thread->ApcState.Process, Thread->ApcState.Process);
-
-       /* Return to old IRQL*/
-       KeReleaseDispatcherDatabaseLock(OldIrql);
+    KIRQL OldIrql;
+    PKTHREAD Thread;
+    ASSERT_IRQL_LESS_OR_EQUAL(DISPATCH_LEVEL);
+
+    /* Make sure that we are in the right page directory */
+    Thread = KeGetCurrentThread();
+    UpdatePageDirs(Thread, Process);
+
+    /* Acquire the dispatcher lock */
+    OldIrql = KeAcquireDispatcherDatabaseLock();
+
+    /* Crash system if DPC is being executed! */
+    if (KeIsExecutingDpc())
+    {
+        /* Executing a DPC, crash! */
+        KEBUGCHECKEX(INVALID_PROCESS_ATTACH_ATTEMPT,
+                     (ULONG_PTR)Process,
+                     (ULONG_PTR)Thread->ApcState.Process,
+                     Thread->ApcStateIndex,
+                     KeIsExecutingDpc());
+    }
+
+    /* Check if we are already in the target process */
+    if (Thread->ApcState.Process == Process)
+    {
+        /* Unlock the dispatcher database */
+        KeReleaseDispatcherDatabaseLock(OldIrql);
+
+        /* Set magic value so we don't crash later when detaching */
+        ApcState->Process = (PKPROCESS)1;
+    }
+    else
+    {
+        /* Check if the Current Thread is already attached */
+        if (Thread->ApcStateIndex != OriginalApcEnvironment)
+        {
+            /* We're already attached, so save the APC State into what we got */
+            KiAttachProcess(Thread, Process, OldIrql, ApcState);
+        }
+        else
+        {
+            /* We're not attached, so save the APC State into SavedApcState */
+            KiAttachProcess(Thread, Process, OldIrql, &Thread->SavedApcState);
+            ApcState->Process = NULL;
+        }
+    }
 }
 
-/* This function should be used by win32k.sys to add its own user32/gdi32 services
- * TableIndex is 0 based
- * ServiceCountTable its not used at the moment
+/*
+ * @implemented
  */
+VOID
+NTAPI
+KeUnstackDetachProcess(IN PRKAPC_STATE ApcState)
+{
+    KIRQL OldIrql;
+    PKTHREAD Thread;
+    ASSERT_IRQL_LESS_OR_EQUAL(DISPATCH_LEVEL);
+
+    /* Get the current thread and acquire the dispatcher lock */
+    Thread = KeGetCurrentThread();
+    OldIrql = KeAcquireDispatcherDatabaseLock();
+
+    /* Check for magic value meaning we were already in the same process */
+    if (ApcState->Process != (PKPROCESS)1)
+    {
+        /*
+         * Check if the process isn't attacked, or has a Kernel APC in progress
+         * or has pending APC of any kind.
+         */
+        if ((Thread->ApcStateIndex == OriginalApcEnvironment) ||
+            (Thread->ApcState.KernelApcInProgress) ||
+            (!IsListEmpty(&Thread->ApcState.ApcListHead[KernelMode])) ||
+            (!IsListEmpty(&Thread->ApcState.ApcListHead[UserMode])))
+        {
+            KEBUGCHECK(INVALID_PROCESS_DETACH_ATTEMPT);
+        }
+
+        /* Decrease Stack Count */
+        if(!(--Thread->ApcState.Process->StackCount))
+        {
+            /* FIXME: Swap the process out */
+        }
+
+        if (ApcState->Process != NULL)
+        {
+            /* Restore the APC State */
+            KiMoveApcState(ApcState, &Thread->ApcState);
+        }
+        else
+        {
+            /* The ApcState parameter is useless, so use the saved data and reset it */
+            KiMoveApcState(&Thread->SavedApcState, &Thread->ApcState);
+            Thread->SavedApcState.Process = NULL;
+            Thread->ApcStateIndex = OriginalApcEnvironment;
+            Thread->ApcStatePointer[OriginalApcEnvironment] = &Thread->ApcState;
+            Thread->ApcStatePointer[AttachedApcEnvironment] = &Thread->SavedApcState;
+        }
+
+        /* Check if we have pending APCs */
+        if (IsListEmpty(&Thread->ApcState.ApcListHead[KernelMode]))
+        {
+            /* What do you know, we do! Request them to be delivered */
+            Thread->ApcState.KernelApcPending = TRUE;
+            HalRequestSoftwareInterrupt(APC_LEVEL);
+        }
+
+        /* Swap Processes */
+        KiSwapProcess(Thread->ApcState.Process, Thread->ApcState.Process);
+    }
+
+    /* Return to old IRQL*/
+    KeReleaseDispatcherDatabaseLock(OldIrql);
+}
+
 /*
  * @implemented
  */
-BOOLEAN STDCALL
-KeAddSystemServiceTable (
-       PSSDT   SSDT,
-       PULONG  ServiceCounterTable,
-       ULONG   NumberOfServices,
-       PSSPT   SSPT,
-       ULONG   TableIndex
-       )
+BOOLEAN
+NTAPI
+KeAddSystemServiceTable(PULONG_PTR Base,
+                        PULONG Count OPTIONAL,
+                        ULONG Limit,
+                        PUCHAR Number,
+                        ULONG Index)
 {
-    /* check if descriptor table entry is free */
-    if ((TableIndex > SSDT_MAX_ENTRIES - 1) ||    
-        (KeServiceDescriptorTable[TableIndex].SSDT != NULL) ||
-        (KeServiceDescriptorTableShadow[TableIndex].SSDT != NULL))
+    /* Check if descriptor table entry is free */
+    if ((Index > SSDT_MAX_ENTRIES - 1) ||
+        (KeServiceDescriptorTable[Index].Base) ||
+        (KeServiceDescriptorTableShadow[Index].Base))
+    {
         return FALSE;
+    }
+
+    /* Initialize the shadow service descriptor table */
+    KeServiceDescriptorTableShadow[Index].Base = Base;
+    KeServiceDescriptorTableShadow[Index].Limit = Limit;
+    KeServiceDescriptorTableShadow[Index].Number = Number;
+    KeServiceDescriptorTableShadow[Index].Count = Count;
 
-    /* initialize the shadow service descriptor table */
-    KeServiceDescriptorTableShadow[TableIndex].SSDT = SSDT;
-    KeServiceDescriptorTableShadow[TableIndex].SSPT = SSPT;
-    KeServiceDescriptorTableShadow[TableIndex].NumberOfServices = NumberOfServices;
-    KeServiceDescriptorTableShadow[TableIndex].ServiceCounterTable = ServiceCounterTable;
-    
     return TRUE;
 }
 
 /*
- * @unimplemented
+ * @implemented
  */
 BOOLEAN
-STDCALL
-KeRemoveSystemServiceTable(
-    IN PUCHAR Number
-)
+NTAPI
+KeRemoveSystemServiceTable(IN ULONG Index)
 {
-       UNIMPLEMENTED;
-       return FALSE;
+    /* Make sure the Index is valid */
+    if (Index > SSDT_MAX_ENTRIES - 1) return FALSE;
+
+    /* Is there a Normal Descriptor Table? */
+    if (!KeServiceDescriptorTable[Index].Base)
+    {
+        /* Not with the index, is there a shadow at least? */
+        if (!KeServiceDescriptorTableShadow[Index].Base) return FALSE;
+    }
+
+    /* Now clear from the Shadow Table. */
+    KeServiceDescriptorTableShadow[Index].Base = NULL;
+    KeServiceDescriptorTableShadow[Index].Number = NULL;
+    KeServiceDescriptorTableShadow[Index].Limit = 0;
+    KeServiceDescriptorTableShadow[Index].Count = NULL;
+
+    /* Check if we should clean from the Master one too */
+    if (Index == 1)
+    {
+        KeServiceDescriptorTable[Index].Base = NULL;
+        KeServiceDescriptorTable[Index].Number = NULL;
+        KeServiceDescriptorTable[Index].Limit = 0;
+        KeServiceDescriptorTable[Index].Count = NULL;
+    }
+
+    return TRUE;
 }
 /* EOF */