/*++

Copyright (c) 1989  Microsoft Corporation

Module Name:

    procobj.c

Abstract:

    This module implements the machine independent functions to manipulate
    the kernel process object. Functions are provided to initilaize, attach,
    detach, exclude, include, and set the base priority of process objects.

Author:

    David N. Cutler (davec) 7-Mar-1989

Environment:

    Kernel mode only.

Revision History:

--*/

#include "ki.h"

#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, KeInitializeProcess)
#endif


//
// Define forward referenced function prototypes.
//

VOID
KiAttachProcess (
    IN PKPROCESS Process,
    IN KIRQL OldIrql
    );

VOID
KiMoveApcState (
    IN PKAPC_STATE Source,
    OUT PKAPC_STATE Destination
    );

//
// The following assert macro is used to check that an input process is
// really a kprocess and not something else, like deallocated pool.
//

#define ASSERT_PROCESS(E) {             \
    ASSERT((E)->Header.Type == ProcessObject); \
}


VOID
KeInitializeProcess (
    IN PRKPROCESS Process,
    IN KPRIORITY BasePriority,
    IN KAFFINITY Affinity,
    IN ULONG DirectoryTableBase[2],
    IN BOOLEAN Enable
    )

/*++

Routine Description:

    This function initializes a kernel process object. The base priority,
    affinity, and page frame numbers for the process page table directory
    and hyper space are stored in the process object.

    N.B. It is assumed that the process object is zeroed.

Arguments:

    Process - Supplies a pointer to a dispatcher object of type process.

    BasePriority - Supplies the base priority of the process.

    Affinity - Supplies the set of processors on which children threads
        of the process can execute.

    DirectoryTableBase - Supplies a pointer to an array whose fist element
        is the value that is to be loaded into the Directory Table Base
        register when a child thread is dispatched for execution and whose
        second element contains the page table entry that maps hyper space.

    Enable - Supplies a boolean value that determines the default
        handling of data alignment exceptions for child threads. A value
        of TRUE causes all data alignment exceptions to be automatically
        handled by the kernel. A value of FALSE causes all data alignment
        exceptions to be actually raised as exceptions.

Return Value:

    None.

--*/

{

    //
    // Initialize the standard dispatcher object header and set the initial
    // signal state of the process object.
    //

    Process->Header.Type = ProcessObject;
    Process->Header.Size = sizeof(KPROCESS) / sizeof(LONG);
    InitializeListHead(&Process->Header.WaitListHead);

    //
    // Initialize the base priority, affinity, directory table base values,
    // autoalignment, and stack count.
    //
    // N.B. The distinguished value MAXSHORT is used to signify that no
    //      threads have been created for the process.
    //

    Process->BasePriority = (SCHAR)BasePriority;
    Process->Affinity = Affinity;
    Process->AutoAlignment = Enable;
    Process->DirectoryTableBase[0] = DirectoryTableBase[0];
    Process->DirectoryTableBase[1] = DirectoryTableBase[1];
    Process->StackCount = MAXSHORT;

    //
    // Initialize the stack count, profile listhead, ready queue list head,
    // accumulated runtime, process quantum, thread quantum, and thread list
    // head.
    //

    InitializeListHead(&Process->ProfileListHead);
    InitializeListHead(&Process->ReadyListHead);
    InitializeListHead(&Process->ThreadListHead);
    Process->ThreadQuantum = THREAD_QUANTUM;

    //
    // Initialize the process state and set the thread processor selection
    // seed.
    //

    Process->State = ProcessInMemory;
    Process->ThreadSeed = (UCHAR)KiQueryLowTickCount();

    //
    // Initialize Ldt descriptor for this process (i386 only)
    //

#ifdef i386

    //
    // Initialize IopmBase and Iopl flag for this process (i386 only)
    //

    Process->IopmOffset = KiComputeIopmOffset(IO_ACCESS_MAP_NONE);

#endif

    return;
}

VOID
KeAttachProcess (
    IN PRKPROCESS Process
    )

/*++

Routine Description:

    This function attaches a thread to a target process' address space.

Arguments:

    Process - Supplies a pointer to a dispatcher object of type process.

Return Value:

    None.

--*/

{

    KIRQL OldIrql;

    ASSERT_PROCESS(Process);
    ASSERT(KeGetCurrentIrql() <= DISPATCH_LEVEL);

    //
    // Raise IRQL to dispatcher level and lock dispatcher database.
    //

    KiLockDispatcherDatabase(&OldIrql);

    //
    // Attach target process.
    //

    KiAttachProcess(Process, OldIrql);
    return;
}

BOOLEAN
KeTryToAttachProcess (
    IN PRKPROCESS Process
    )

/*++

Routine Description:

    This function tries to attach a thread to a target process' address
    space. If the target process is in memory or out of memory, then the
    target process is attached. Otherwise, it is not attached.

    N.B. If the target process state is out of memory, then the caller
        must have all pages for the process in memory. This function is
        intended for use by the memory management system.

Arguments:

    Process - Supplies a pointer to a dispatcher object of type process.

Return Value:

    If the target process state is not in transistion, then the target
    process is atached and a value of TRUE is returned. Otherwise, a
    value of FALSE is returned.

--*/

{

    KIRQL OldIrql;

    ASSERT_PROCESS(Process);
    ASSERT(KeGetCurrentIrql() <= DISPATCH_LEVEL);

    //
    // Raise IRQL to dispatcher level and lock dispatcher database.
    //

    KiLockDispatcherDatabase(&OldIrql);

    //
    // If the target process state is not in transition, then set the
    // target process state to in memory, attach the process, and return
    // a value of TRUE. Otherwise, unlock the dispatcher database and
    // return a value of FALSE.
    //

    if (Process->State != ProcessInTransition) {
        Process->State = ProcessInMemory;
        KiAttachProcess(Process, OldIrql);
        return TRUE;

    } else {
        KiUnlockDispatcherDatabase(OldIrql);
        return FALSE;
    }
}

VOID
KeDetachProcess (
    VOID
    )

/*++

Routine Description:

    This function detaches a thread from another process' address space.

Arguments:

    None.

Return Value:

    None.

--*/

{

    KIRQL OldIrql;
    PKPROCESS Process;
    PKTHREAD Thread;

    ASSERT(KeGetCurrentIrql() <= DISPATCH_LEVEL);

    //
    // Raise IRQL to dispatcher level and lock dispatcher database.
    //

    Thread = KeGetCurrentThread();
    KiLockDispatcherDatabase(&OldIrql);

    //
    // If the current thread is attached to another address, then detach
    // it.
    //

    if (Thread->ApcStateIndex != 0) {

        //
        // Check if a kernel APC is in progress, the kernel APC queue is
        // not empty, or the user APC queue is not empty. If any of these
        // conditions are true, then call bug check.
        //

#if DBG

        if ((Thread->ApcState.KernelApcInProgress) ||
            (IsListEmpty(&Thread->ApcState.ApcListHead[KernelMode]) == FALSE) ||
            (IsListEmpty(&Thread->ApcState.ApcListHead[UserMode]) == FALSE)) {
            KeBugCheck(INVALID_PROCESS_DETACH_ATTEMPT);
        }

#endif

        //
        // Unbias current process stack count and check if the process should
        // be swapped out of memory.
        //

        Process = Thread->ApcState.Process;
        Process->StackCount -= 1;
        if (Process->StackCount == 0) {
            Process->State = ProcessInTransition;
            InsertTailList(&KiProcessOutSwapListHead, &Process->SwapListEntry);
            KiSwapEvent.Header.SignalState = 1;
            if (IsListEmpty(&KiSwapEvent.Header.WaitListHead) == FALSE) {
                KiWaitTest(&KiSwapEvent, BALANCE_INCREMENT);
            }
        }

        //
        // Restore APC state and check whether the kernel APC queue contains
        // an entry. If the kernel APC queue contains an entry then set kernel
        // APC pending and request a software interrupt at APC_LEVEL.
        //

        KiMoveApcState(&Thread->SavedApcState, &Thread->ApcState);
        Thread->SavedApcState.Process = (PKPROCESS)NULL;
        Thread->ApcStatePointer[0] = &Thread->ApcState;
        Thread->ApcStatePointer[1] = &Thread->SavedApcState;
        Thread->ApcStateIndex = 0;
        if (IsListEmpty(&Thread->ApcState.ApcListHead[KernelMode]) == FALSE) {
            Thread->ApcState.KernelApcPending = TRUE;
            KiRequestSoftwareInterrupt(APC_LEVEL);
        }

        //
        // Swap the address space back to the parent process.
        //

        KiSwapProcess(Thread->ApcState.Process, Process);

    }

    //
    // Lower IRQL to its previous value and return.
    //

    KiUnlockDispatcherDatabase(OldIrql);
    return;
}

LONG
KeReadStateProcess (
    IN PRKPROCESS Process
    )

/*++

Routine Description:

    This function reads the current signal state of a process object.

Arguments:

    Process - Supplies a pointer to a dispatcher object of type process.

Return Value:

    The current signal state of the process object.

--*/

{

    ASSERT_PROCESS(Process);

    //
    // Return current signal state of process object.
    //

    return Process->Header.SignalState;
}

LONG
KeSetProcess (
    IN PRKPROCESS Process,
    IN KPRIORITY Increment,
    IN BOOLEAN Wait
    )

/*++

Routine Description:

    This function sets the signal state of a proces object to Signaled
    and attempts to satisfy as many Waits as possible. The previous
    signal state of the process object is returned as the function value.

Arguments:

    Process - Supplies a pointer to a dispatcher object of type process.

    Increment - Supplies the priority increment that is to be applied
       if setting the process causes a Wait to be satisfied.

    Wait - Supplies a boolean value that signifies whether the call to
       KeSetProcess will be immediately followed by a call to one of the
       kernel Wait functions.

Return Value:

    The previous signal state of the process object.

--*/

{

    KIRQL OldIrql;
    LONG OldState;
    PRKTHREAD Thread;

    ASSERT_PROCESS(Process);
    ASSERT(KeGetCurrentIrql() <= DISPATCH_LEVEL);

    //
    // Raise IRQL to dispatcher level and lock dispatcher database.
    //

    KiLockDispatcherDatabase(&OldIrql);

    //
    // If the previous state of the process object is Not-Signaled and
    // the wait queue is not empty, then satisfy as many Waits as
    // possible.
    //

    OldState = Process->Header.SignalState;
    Process->Header.SignalState = 1;
    if ((OldState == 0) && (!IsListEmpty(&Process->Header.WaitListHead))) {
        KiWaitTest(Process, Increment);
    }

    //
    // If the value of the Wait argument is TRUE, then return to the
    // caller with IRQL raised and the dispatcher database locked. Else
    // release the dispatcher database lock and lower IRQL to its
    // previous value.
    //

    if (Wait) {
        Thread = KeGetCurrentThread();
        Thread->WaitNext = Wait;
        Thread->WaitIrql = OldIrql;

    } else {
        KiUnlockDispatcherDatabase(OldIrql);
    }

    //
    // Return previous signal state of process object.
    //

    return OldState;
}

KPRIORITY
KeSetPriorityProcess (
    IN PKPROCESS Process,
    IN KPRIORITY NewBase
    )

/*++

Routine Description:

    This function set the base priority of a process to a new value
    and adjusts the priority and base priority of all child threads
    as appropriate.

Arguments:

    Process - Supplies a pointer to a dispatcher object of type process.

    NewBase - Supplies the new base priority of the process.

Return Value:

    The previous base priority of the process.

--*/

{

    KPRIORITY Adjustment;
    PLIST_ENTRY NextEntry;
    KPRIORITY NewPriority;
    KIRQL OldIrql;
    KPRIORITY OldBase;
    PKTHREAD Thread;

    ASSERT_PROCESS(Process);
    ASSERT(KeGetCurrentIrql() <= DISPATCH_LEVEL);

    //
    // Raise IRQL to dispatcher level and lock dispatcher database.
    //

    KiLockDispatcherDatabase(&OldIrql);

    //
    // Save the current process base priority, set the new process base
    // priority, compute the adjustment value, and adjust the priority
    // and base priority of all child threads as appropriate.
    //

    OldBase = Process->BasePriority;
    Process->BasePriority = (SCHAR)NewBase;
    Adjustment = NewBase - OldBase;
    NextEntry = Process->ThreadListHead.Flink;
    if (NewBase >= LOW_REALTIME_PRIORITY) {
        while (NextEntry != &Process->ThreadListHead) {
            Thread = CONTAINING_RECORD(NextEntry, KTHREAD, ThreadListEntry);

            //
            // Compute the new base priority of the thread.
            //

            NewPriority = Thread->BasePriority + Adjustment;

            //
            // If the new base priority is outside the realtime class,
            // then limit the change to the realtime class.
            //

            if (NewPriority < LOW_REALTIME_PRIORITY) {
                NewPriority = LOW_REALTIME_PRIORITY;

            } else if (NewPriority > HIGH_PRIORITY) {
                NewPriority = HIGH_PRIORITY;
            }

            //
            // Set the base priority and the current priority of the
            // thread to the computed value and reset the thread quantum.
            //
            // N.B. If priority saturation occured the last time the thread
            //      base priority was set and the new process base priority
            //      is not crossing from variable to realtime, then the thread
            //      priority is not changed.
            //

            if ((Thread->Saturation == FALSE) || (OldBase < LOW_REALTIME_PRIORITY)) {
                Thread->BasePriority = (SCHAR)NewPriority;
                Thread->Quantum = Process->ThreadQuantum;
                Thread->DecrementCount = 0;
                Thread->PriorityDecrement = 0;
                Thread->Saturation = FALSE;
                KiSetPriorityThread(Thread, NewPriority);
            }

            NextEntry = NextEntry->Flink;
        }

    } else {
        while (NextEntry != &Process->ThreadListHead) {
            Thread = CONTAINING_RECORD(NextEntry, KTHREAD, ThreadListEntry);

            //
            // Compute the new base priority of the thread.
            //

            NewPriority = Thread->BasePriority + Adjustment;

            //
            // If the new base priority is outside the variable class,
            // then limit the change to the variable class.
            //

            if (NewPriority >= LOW_REALTIME_PRIORITY) {
                NewPriority = LOW_REALTIME_PRIORITY - 1;

            } else if (NewPriority <= LOW_PRIORITY) {
                NewPriority = 1;
            }

            //
            // Set the base priority and the current priority of the
            // thread to the computed value and reset the thread quantum.
            //
            // N.B. If priority saturation occured the last time the thread
            //      base priority was set and the new process base priority
            //      is not crossing from realtime to variable, then the thread
            //      priority is not changed.
            //

            if ((Thread->Saturation == FALSE) || (OldBase >= LOW_REALTIME_PRIORITY)) {
                Thread->BasePriority = (SCHAR)NewPriority;
                Thread->Quantum = Process->ThreadQuantum;
                Thread->DecrementCount = 0;
                Thread->PriorityDecrement = 0;
                Thread->Saturation = FALSE;
                KiSetPriorityThread(Thread, NewPriority);
            }

            NextEntry = NextEntry->Flink;
        }
    }

    //
    // Unlock dispatcher database and lower IRQL to its previous
    // value.
    //

    KiUnlockDispatcherDatabase(OldIrql);

    //
    // Return previous process base priority
    //

    return OldBase;
}

VOID
KiAttachProcess (
    IN PKPROCESS Process,
    IN KIRQL OldIrql
    )

/*++

Routine Description:

    This function attaches a thread to a target process' address space.

    N.B. The dispatcher database lock must be held when this routine is
        called.

Arguments:

    Process - Supplies a pointer to a dispatcher object of type process.

    Thread - Supplies a pointer to a dispatcher object of type thread.

    OldIrql - Supplies the previous IRQL.

Return Value:

    None.

--*/

{

    PRKTHREAD Thread;
    KAFFINITY Processor;

    //
    // Get the address of the current thread object.
    //

    Thread = KeGetCurrentThread();

    //
    // Check whether there is already a process address space attached or
    // the thread is executing a DPC. If either condition is true, then call
    // bug check.
    //

    if (Process != Thread->ApcState.Process) {
        if ((Thread->ApcStateIndex != 0) ||
            (KeIsExecutingDpc() != FALSE)) {
            KeBugCheckEx(
                INVALID_PROCESS_ATTACH_ATTEMPT,
                (ULONG)Process,
                (ULONG)Thread->ApcState.Process,
                (ULONG)Thread->ApcStateIndex,
                (ULONG)KeIsExecutingDpc()
                );
        }
    }

    //
    // If the target process is the same as the current process, then
    // there is no need to attach the address space. Otherwise, attach
    // the current thread to the target thread address space.
    //

    if (Process == Thread->ApcState.Process) {
        KiUnlockDispatcherDatabase(OldIrql);

    } else {

        //
        // Bias the stack count of the target process to signify that a
        // thread exists in that process with a stack that is resident.
        //

        Process->StackCount += 1;

        //
        // Save current APC state and initialize A new APC state.
        //

        KiMoveApcState(&Thread->ApcState, &Thread->SavedApcState);
        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;
        Thread->ApcStatePointer[0] = &Thread->SavedApcState;
        Thread->ApcStatePointer[1] = &Thread->ApcState;
        Thread->ApcStateIndex = 1;

        //
        // If the target process is in memory, then immediately enter the
        // new address space by loading a new Directory Table Base. Otherwise,
        // insert the current thread in the target process ready list, inswap
        // the target process if necessary, select a new thread to run on the
        // the current processor and context switch to the new thread.
        //

        if (Process->State == ProcessInMemory) {
            KiSwapProcess(Process, Thread->SavedApcState.Process);
            KiUnlockDispatcherDatabase(OldIrql);

        } else {
            Thread->State = Ready;
            Thread->ProcessReadyQueue = TRUE;
            InsertTailList(&Process->ReadyListHead, &Thread->WaitListEntry);
            if (Process->State == ProcessOutOfMemory) {
                Process->State = ProcessInTransition;
                InsertTailList(&KiProcessInSwapListHead, &Process->SwapListEntry);
                KiSwapEvent.Header.SignalState = 1;
                if (IsListEmpty(&KiSwapEvent.Header.WaitListHead) == FALSE) {
                    KiWaitTest(&KiSwapEvent, BALANCE_INCREMENT);
                }
            }

            //
            // Clear the active processor bit in the previous process and
            // set active processor bit in the process being attached to.
            //

#if !defined(NT_UP)

            Processor = KeGetCurrentPrcb()->SetMember;
            Thread->SavedApcState.Process->ActiveProcessors &= ~Processor;
            Process->ActiveProcessors |= Processor;

#endif

            Thread->WaitIrql = OldIrql;

            KiSwapThread();

        }
    }

    return;
}

VOID
KiMoveApcState (
    IN PKAPC_STATE Source,
    OUT PKAPC_STATE Destination
    )

/*++

Routine Description:

    This function moves the APC state from the source structure to the
    destination structure and reinitializes list headers as appropriate.

Arguments:

    Source - Supplies a pointer to the source APC state structure.

    Destination - Supplies a pointer to the destination APC state structure.


Return Value:

    None.

--*/

{

    PLIST_ENTRY First;
    PLIST_ENTRY Last;

    //
    // Copy the APC state from the source to the destination.
    //

#if defined(_M_PPC) && (_MSC_VER >= 1000)
    KIRQL OldIrql;
    KeRaiseIrql(HIGH_LEVEL, &OldIrql);
#endif

    *Destination = *Source;

#if defined(_M_PPC) && (_MSC_VER >= 1000)
    KeLowerIrql(OldIrql);
#endif

    if (IsListEmpty(&Source->ApcListHead[KernelMode]) != FALSE) {
        InitializeListHead(&Destination->ApcListHead[KernelMode]);

    } else {
        First = Source->ApcListHead[KernelMode].Flink;
        Last = Source->ApcListHead[KernelMode].Blink;
        Destination->ApcListHead[KernelMode].Flink = First;
        Destination->ApcListHead[KernelMode].Blink = Last;
        First->Blink = &Destination->ApcListHead[KernelMode];
        Last->Flink = &Destination->ApcListHead[KernelMode];
    }

    if (IsListEmpty(&Source->ApcListHead[UserMode]) != FALSE) {
        InitializeListHead(&Destination->ApcListHead[UserMode]);

    } else {
        First = Source->ApcListHead[UserMode].Flink;
        Last = Source->ApcListHead[UserMode].Blink;
        Destination->ApcListHead[UserMode].Flink = First;
        Destination->ApcListHead[UserMode].Blink = Last;
        First->Blink = &Destination->ApcListHead[UserMode];
        Last->Flink = &Destination->ApcListHead[UserMode];
    }

    return;
}